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The effect of indomethacin on alveolar bone loss in periodontitis
Abstract
This study was undertaken to determine if prostaglandins play a role in the events leading to loss of bone in the ligature model of periodontitis. Periodontitis was induced by placement of the ligatures around mandibular teeth on one side of the jaw of squirrel monkeys (Saimiri sciureus). From one day prior to ligature placement, half the animals were administered indomethacin (5 mg/kg/day), a potent inhibitor of prostaglandin synthesis. Animals were sacrificed after one and two weeks of experimental periodontitis. It was found that indomethacin treatment abolished the significant losses of alveolar bone height and bone mass seen in non-indomethacin-treated (NIT) animals following ligature placement. Indomethacin also depressed the large increase in osteoclast density measured at one week in the NIT animals. The results support the hypothesis that prostaglandins are an important mediator of bone loss in the ligature model of periodontitis. Evidence is also presented for the coupling of bone resorption with osteoblastic neo-osteogenesis on both periodontal ligament and endosteal bone surfaces.
... Non-steroidal antiinflammatory drugs (NSAIDs) have been proposed as an adjunct to periodontal treatment repeatedly, for obvious reasons [43]. Being cyclooxygenase inhibitors, they have been shown to reduce periodontal inflammation substantially [44,45]. However, adjunctive effects of reasonable dosing schemes on periodontal therapy were not confirmed by clinical studies [46]. ...
The regenerative capacity of well-preserved blood clots may be enhanced by biologics like enamel matrix derivative (EMD). This retrospective analysis compares outcomes reported by three centers using different heterografts. Center 1 (C1) treated intrabony defects combining cross-linked high-molecular-weight hyaluronic acid (xHyA) with a xenograft; center 2 (C2) used EMD with an allograft combination to graft a residual pocket. Center 3 (C3) combined xHyA with the placement of a resorbable polymer membrane for defect cover. Clinical parameters, BoP reduction, and radiographically observed defect fill at 12-month examination are reported. The 12-month evaluation yielded significant improvements in PPD and CAL at each center (p < 0.001, respectively). Analyses of Covariance revealed significant improvements in all parameters, and a significantly greater CAL gain was revealed for C2 vs. C1 (p = 0.006). Radiographic defect fill presented significantly higher scores for C2 and C3 vs. C1 (p = 0.003 and = 0.014; C2 vs. C3 p = 1.00). Gingival recession increased in C1 and C3 (p = 1.00), while C2 reported no GR after 12 months (C2:C1 p = 0.002; C2:C3 p = 0.005). BoP tendency and pocket closure rate shared similar rates. Within the limitations of the study, a data comparison indicated that xHyA showed a similar capacity to enhance the regenerative response, as known for EMD. Radiographic follow-up underlined xHyA’s unique role in new attachment formation.
... The first drug tested was indomethacin [85]. Its therapeutic effects have been demonstrated in dogs, rodents, and primates [85,86]. Indomethacin reduced bone recession and resulted in reduction in the incidence of this disease following its use. ...
Periodontal disease in ruminants is common and occurs in farmed and wild animals. Periodontal lesions can result from the secretion of endotoxins by pathogenic bacteria and as consequences of immune system activity. Three main types of periodontitis have been described. The first is chronic inflammation involving mainly premolars and molars—periodontitis (PD). The second type is an acute inflammatory reaction occurring with calcification of the periosteum of the jawbone and swelling of the surrounding soft tissues (Cara inchada, CI—“swollen face”). Finally, a third type, similar to the first but located in the incisor area, is called “broken mouth” (BM). Etiological variation between the different types of periodontitis is indicated. This particularly manifests in the composition of the microbiome, which is characteristic of the different forms of periodontitis. The widespread detection of lesions has drawn attention to the current nature of the problem.
... The results demonstrated that indomethacin delayed the initiation and reduced the severity of ligature-induced periodontitis and suppressed bone resorption. The findings were further verified by another study in squirrel monkeys [61]. ...
Periodontitis is the sixth most prevalent chronic disease globally and places significant burdens on societies and economies worldwide. Behavioral modification, risk factor control, coupled with cause-related therapy have been the “gold standard” treatment for managing periodontitis. Given that host inflammatory and immunological responses play critical roles in the pathogenesis of periodontitis and impact treatment responses, several adjunctive strategies aimed at modulating host responses and improving the results of periodontal therapy and maintenance have been proposed. Of the many pharmacological host modulators, we focused on non-steroidal anti-inflammatory drugs (NSAIDs), due to their long history and extensive use in relieving inflammation and pain and reducing platelet aggregation. NSAIDs have been routinely indicated for treating rheumatic fever and osteoarthritis and utilized for the prevention of cardiovascular events. Although several efforts have been made to incorporate NSAIDs into the treatment of periodontitis, their effects on periodontal health remain poorly characterized, and concerns over the risk–benefit ratio were also raised. Moreover, there is emerging evidence highlighting the potential of NSAIDs, especially aspirin, for use in periodontal regeneration. This review summarizes and discusses the use of NSAIDs in various aspects of periodontal therapy and regeneration, demonstrating that the benefits of NSAIDs as adjuncts to conventional periodontal therapy remain controversial. More recent evidence suggests a promising role for NSAIDs in periodontal tissue engineering and regeneration.
... Although it is difficult to extrapolate the results of animal studies to humans, it is equally unwise to ignore the many similarities that scientists have demonstrated in these models 13 . Many animal models using NSAIDs of experimental periodontal disease have been proposed throughout the years, such as ligature induced periodontitis 4,14 and periodontitis induced by diet consistence modification [5][6][7]15 . These are the most effective methods to accumulate plaque and induce periodontal disease (Table 1). ...
Periodontal diseases are infecto-inflammatory diseases. Literature, has tried to elucidate the infections component of gingivitis and periodontitis, for several years. In recent years, much has been discussed about the role of the host response modulators to periodontal therapeutic procedures. The aim of the present literature review was to evaluate the effect of host response modulating agents (anti-inflammatories) on the pathogenesis of gingivitis and periodontitis. A search in the main databases was performed and human and animal studies were selected. The majority of studies was performed in humans and non-steroidal anti-inflammatory drugs in different dosages were used. The results have shown a potential benefit of the non-steroidal anti-inflammatory drugs concerning the microbial challenge. However, this benefit seems not to occur in the long term, thus not supporting it as a periodontal therapeutic approach. Few studies evaluated the effect of steroidal anti-inflammatory drugs on the pathogenesis of periodontal diseases. Moreover, the results in humans and animals are controversial, pointing to a possible deleterious effect of steroidal anti-inflammatory drugs on periodontal structures.
... Recently, Dybvig also validated that prostaglandins are an important mediator of bone loss in periodontitis. [26] Non-steroidal anti-inflammatory (NSAIDs) drugs block the activity of both cyclooxygenase isozymes (COX-1 and -2) and many authors have demonstrated the role of NSAIDs like flurbiprofen, [27] indomethacin, [28] and naproxen, [29] in inhibiting gingivitis and progression of periodontitis. Lipoxins (LX) which are generated endogenously late in inflammation via cell-cell interaction when a second lipoxygenase (e.g. ...
Traditionally, only antimicrobials have been used as the chemotherapeutic modality for the treatment of periodontitis. Though bacteria are the primary etiologic factors of periodontal diseases, yet the extent and severity of tissue destruction seen in periodontitis is determined by the host immuno-inflammatory response to these bacteria. This increasing awareness and knowledge of the host-microbial interaction in periodontal pathogenesis has presented the opportunity for exploring new therapeutic strategies for periodontitis by means of targeting host response via host-modulating agents. This has lead to the emergence of the field of "Perioceutics" i.e. the use of parmacotherapeutic agents including antimicrobial therapy as well as host modulatory therapy for the management of periodontitis. These host-modulating agents used as an adjunct tip the balance between periodontal health and disease progression in the direction of a healing response. In this article the host-modulating role of various systemically and locally delivered perioceutic agents will be reviewed.
... Elevated PGE^ levels have been associated with periodontal bone resorption. Administration of NSAIDs such as indomethacin and fiurbiprofen which directly inhibit cyclooxygenase and therefore, the biosynthesis of prostaglandins, have been extensively studied as a means of decreasing attachment loss and alveolar bone resorption (Nyman et al. 1979, Weaks-Dybvig et al. 1982. Williams et al. 1989). ...
Abstract Increased levels of cytokines and prostanoids have been detected in inflamed gingival tissue and may play an important role in periodontal pathogenesis. Recent studies suggest that monocytic products, such as interleukin (IL)-1β, could stimulate IL-6 production by human gingival fibroblasts (HGF). In this context, the production of local cytokines and inflammatory mediators could regulate the secretory capacity of resident gingival fibroblasts. Therefore, the purpose of this study was to determine if PGE2 induced by IL-1β could potentiate the IL-6 response by HGF. Utilizing an ELISA, it was determined that maximal IL-6 occurred when HGF were stimulated with 0.10–10 nM IL-1β. These concentrations of IL-1β also induced a small, but significant increase in PGE2 production by HGF. Interestingly, the combination of ILγβ and PGE2 induced a synergistic rise in IL-6 production by HGF. Moreover, inclusion of indomethacin caused a 20% reduction in IL-6 production and totally eliminated PGE2 production. These findings provide additional rationale for the clinical use of NSAIDs in the management of periodontal disease due to their ability to attenuate production of both PGE2, and IL-6. These results suggest the endogenous PGE2 induced by IL-1β plays an important regulatory role in IL 6 production by HGF. Moreover, they support the concept that elevated PGE2 induced during inflammation can regulate HGF secretory function.
... Then, various researchers such as Offenbacher et al, (1987) corroborated the effect of different systemic or topical NSAIDs and showed reduction in alveolar bone loss in preclinical periodontal disease models. With the success in animal models, the researchers logically looked for the effect of NSAIDs in inhibition of bone loss associated with human periodontal disease (Nyman 1979, Weaks-Dybvig 1982, Williams 1987). The principal mechanism of action of NSAIDs is inhibition of cyclooxygenase. ...
Periodontal disease is a multifactorial pathogenic condition involving microbial infection, inflammation, and various systemic complications. Here, a systematic and comprehensive review discussing key-points such as the pros and cons of conventional methods, new advancements, challenges, patents and products, and future prospects is presented. A systematic review process was adopted here by using the following keywords: periodontal diseases, pathogenesis, models, patents, challenges, recent developments, and 3-D printing scaffolds. Search engines used were “google scholar”, “web of science”, “scopus”, and “pubmed”, along with textbooks published over the last few decades. A thorough study of the published data rendered an accurate and deep understanding of periodontal diseases, the gap of research so far, and future opportunities. Formulation scientists and doctors need to be interconnected for a better understanding of the disease to prescribe a quality product. Moreover, prime challenges (such as a lack of a vital testing model, scarcity of clinical and preclinical data, products allowing for high drug access to deeper tissue regions for prolonged residence, lack of an international monitoring body, lack of 4D or time controlled scaffolds, and lack of successful AI based tools) exist that must be addressed for designing new quality products. Generally, several products have been commercialized to treat periodontal diseases with certain limitations. Various strategic approaches have been attempted to target certain delivery regions, maximize residence time, improve efficacy, and reduce toxicity. Conclusively, the current review summarizes valuable information for researchers and healthcare professional to treat a wide range of periodontal diseases.
The term periodontal refers to any of the bony and soft tissues that support the teeth. Diseases of these supporting tissues affect the majority of the adult population throughout the world and are the major cause of loss of teeth in adults. The most common form of periodontal disease and the major consideration of this chapter is chronic adult periodontitis (CAP). The pathologic process(es) involved in CAP are initiated and sustained by bacteria in the dental plaque adherent to the teeth. In the absence of these bacteria, the disease can neither begin nor progress, but the destructive process of CAP does not appear to require the presence of organisms within the periodontal tissues. Thus, seman-tically, CAP is more properly classified as an infestation than an infection. As with other pathological infestations, bacterial products initiate the host response in the tissues; this response is the major source of destruction. Two of the most interesting aspects of the study of this disease concern the nature of the écologie development of the initiating mixed bacterial flora and the mechanisms involved in the breakdown of supporting tissues by the host response. Indeed, much of the knowledge gained by researchers interested in the immunopathology of CAP is applicable to the mechanisms of tissue destruction in other chronic inflammatory diseases such as rheumatoid arthritis (Snyderman and McCarty, 1982; Decker et al., 1984).
Periodontal diseases are the major cause of tooth mortality in many industrialized countries and most developing nations. The significance of microorganisms in the development of virtually all types of periodontal disease is indisputable. This book is an encyclopedic collection of data from scientific papers and textbooks that form a sound basis for a thorough understanding of the antibiotics and antiseptics used in periodontal therapy. The prophylactic, systemic, and topical uses of antibiotics are discussed in detail, identifying the indications, advantages, disadvantages, and efficacy of each approach and regimen. The use of antiseptics is also carefully examined, with particular attention to the merits of different delivery methods and oral hygiene agents. The closing chapter addresses the role of non-steroidal anti-inflammatory drugs. This book will be of value to undergraduate and postgraduate dental students, dental hygienists, dental practitioners, and other associated professionals.
Though bacteria are the primary etiologic factor of periodontal diseases, yet the extent and severity of tissue destruction seen in periodontal diseases is determined by the host immuno-inflammatory response to these bacteria. This increasing awareness and knowledge of the host-microbial interaction in periodontal pathogenesis has presented the opportunity for exploiting new therapeutic strategies for periodontitis by means of targeting host response via host modulating agents. Host modulation means supplementing the natural inherent defense mechanisms of the host by modifying or modulating destructive or damaging aspects of the inflammatory host response that develops in the periodontal tissues as a result of the chronic challenge presented by the subgingival bacterial. This chapter discusses the host-modulating role of various systemically delivered (Tetracycline analogues, NSAIDs, lipoxins, resolvins, protectins, maresin, anti-cytokines, bisphosphonates, probiotics, periodontal vaccine and certain nutrients) and locally delivered agents (Enamel matrix proteins, bone morphogenetic protein, platelet derived growth factor, hypochlorous acid and taurine-N-monochloramine and cimetidine). These host-modulating agents are potentially non-invasive, have fewer side effects, do not require complicated application method and tip the balance between periodontal health and disease progression in the direction of a healing response, when combined with conventional treatments aimed at reducing the bacterial burden.
Periodontal disease is caused by inflammatory processes initiated by the presence of a biofilm. The management of this disease process is largely achieved by disrupting the biofilm to allow regression of inflammation and healing. As our patients are living for longer they are likely to have been exposed to systemic medications that aim to reduce inflammation. These drugs have been shown to decrease inflammation within the periodontal tissues despite not being a primary function of their use. This paper aims to review the relative effects of common systemic medications on the periodontal tissues by analyzing their modes of action and discussing current research and the implications for periodontal treatment.
A double-blind, placebo-controlled trial was conducted to determine the effects of the nonsteroidal anti-inflammatory drug Naprosyn® (naproxen) on gingival inflammation. The enrollment of 114 patients provided 102 patients valid for efficacy evaluation, each having a mean gingival index (GI) score of 1.5 or greater at test-teeth sites. Patients were given oral Naprosyn 500 mg b.i.d. or placebo for 30 days. At 28 d, full-mouth prophylaxis was performed. Gingival index, modified sulcular bleeding index (SBI), and plaque index (PI) scores were taken at baseline, at 28 d, and at 30 d. When the 28-d index measurements were compared to baseline, the drug had no significant effect on plaque index scores or gingival inflammation. Statistically, Naprosyn enhanced the resolution of gingival inflammation following removal of microbial plaque. Thus, although this drug does not suppress the inflammation-inducing properties of plaque, Naprosyn may enhance recovery following plaque removal.
Prostaglandin E2 (PGE2), thromboxane A2 (TXA2), and prostacyclin (PGI2) are naturally occurring metabolites of arachidonic acid which have been associated with inflammation. To assess the relative importance of these mediators in periodontal diseases, the levels of all three were measured by radioimmunoassay in human tissues removed during surgery. TXA2 and PGI2 were determined as their stable hydrolysis products thromboxane B2 (TXB2) and 6-keto-prostaglandin F1α (6-K-PGF1α), respectively. Tissues from periodontal pockets were separated into superficial (n = 8) and deep (n = 22) samples. Noninflamed gingival samples (n = 3) were taken from distal wedges with no clinical evidence of periodontal disease. Most of the samples taken from deep sites (73%) had measurable PGE2 with a mean level of 122 pg/mg. Half of these samples also had measurable TXB2 which correlated positively with levels of PGE2. Half of the superficial gingival samples had detectable levels of PGE2, and none had detectable TXB2. 6-K-PGF1α was found in virtually all samples but at somewhat lower levels in noninflamed tissue. Neither PGE2 nor TXB2 were detected in noninflamed samples.
Abstract – This study compared the periodontal health of patients with SLE with that of healthy controls. Patients with systemic lupus erythematosus had significantly lower periodontal probing depths compared with healthy controls. It is possible that systemic drugs such as corticosteroids and NSAIDS may be responsible for these reduced probing depths but this study did not reveal a statistically significant effect of drugs. There is thus no evidence for a predisposition to increased periodontal disease in SLE.
Non-steroidal anti-inflammatory drugs reduce the acute inflammatory reaction and alveolar bone loss of experimental periodontitis in dogs by mechanisms thought to be associated with the inhibition of prostaglandin synthesis. 25 healthy volunteers abstained from tooth cleaning for 21 days. Experimental gingivitis developed in all subjects. On day 21, the subjects were divided into 3 treatment groups; oral flurbiprofen (100 mg/day) + toothbrushing (A), placebo + toothbrushing (B) and oral flurbiprofen (100 mg/day) only (C). Treatment continued for 6 days. Plaque indices (PI), gingival indices (GI) and probing pocket depths (PPD) were recorded at 6 points on each of 6 maxillary teeth on days 1, 22, 23, 24 and 27. Crevicular fluid flow (CFF) was quantified with a Periotron on days 1. 22 and 27 in groups A and B, and on days 1 and 27 in group C. There were no changes in PPD throughout the study. A reduction of GI occurred between days 22 and 27 for all treatment groups. CFF was also reduced between days 22 and 27 in groups A and B. The differences between the 3 treatments were very small. It is concluded that systemic flurbiprofen (100 mg/day) can reduce the signs of an experimental gingivitis over 6 days. This effect may be seen when the drug is used alone and as an adjunct to toothbrushing.
The present study was designed to examine whether systemic administration of a bisphosphonate, risedronate, could prevent alveolar bone resorption in rats with experimental periodontitis. On Day 1, an elastic ring was placed around the neck of the right mandibular 1st molar to induce inflammatory periodontitis. The animals were given daily injections of either 0.9% NaCl (control group), or 0.8, 1.6 or 3.2 Öoles/kg (s.c.) of risedronate (experimental groups) from Days 1 to 7, and were killed on Day 8. Histological examinations and determination of bone mineral density in the interdental area between the 1st and 2nd molars with an image analyzer revealed that the presence of the elastic ring induced a loss of attachment and bone resorption in the control group. Vigorous bone resorption, with appearance of a large number of osteoclasts, was observed in the interdental and bifurcation areas. In the experimental groups, however, the resorption of alveolar bone and the loss of bone mineral content in these areas were prevented in a dose-dependent fashion, especially at doses of 1.6 and 3.2 Ömoles/kg. Many osteoclasts were detached from the surface of the alveolar bone and had degenerated appearances, such as rounded shapes, loss of polarity and pyknosis. These results suggest that administration of risedronate is effective in preventing bone resorption in periodontitis.
The inhibitory effect of some non-steroidal anti-inflammatory drugs (NSAIDs) on bone resorption is well documented. To explore the effect of NSAIDs on bone formation, we investigated the time course and dose/response characteristics of treatment with various non-steroidal anti-inflammatory drugs (NSAIDs) on ectopic bone formation induced by demineralized bone matrix (DBM) in the rat model. Using biochemical assays, both inhibitory and stimulatory effects on bone formation were found in rats treated with NSAIDs prior to DBM implantation depending on the type and amount of drug administered. There appears to be an enhancement of bone formation for acetaminophen (50 mg/kg), acetylsalicylic acid (50 mg/kg), and ibuprofen (50 mg/kg). Indomethacin (4 mg/kg) and piroxicam (4 mg/kg) had inhibitory effects. Flurbiprofen, on the other hand, did not appear to affect bone formation significantly. In contrast, there was no effect of NSAIDs on bone formation in rats treated with the drugs after implantation of the DBM. It appears that the time course of the drug administration is critical, suggesting that early events in bone formation may be modulated by arachidonic acid metabolites.
Abstract Prostaglandins are believed to be important mediators of periodontal inflammation and bone resorption. The purpose of the present blind study was to quantify clinically and histologically the effects of a topically applied non-steroidal prostaglandin synthetase inhibitor, namely a substituted oxazolopyridine derivative (SOPD), on ligature-induced periodontal disease in the squirrel monkey. For a period of 14 days, one group of ligated animals received 2 daily topical applications of the SOPD. A group receiving systemically administered indomethacin served as a positive control while a group receiving only topically applied vehicle served as a negative control. Results indicate that throughout the 14-day period of the study, the SOPD significantly inhibited gingival inflammation and loss of attachment as compared to either the placebo or indomethacin groups. Both indomethacin and the SOPD significantly inhibited bone resorption.
A consistent observation in osteoporosis is bone volume reduction accompanied by increased marrow adipose tissue. No single
cause linking the two phenomena has yet been identified. In a human progenitor cell clone (hOP 7) derived from bone marrow,
however, we have demonstrated that rabbit serum can direct differentiation away from an osteoblast lineage to one of adipocytes.
We now report on whether human serum has a similar effect. Serum was collected from 10 pre- and 10 postmenopausal women and
from the 10 postmenopausal women before and following 6-week hormone replacement therapy (HRT). hOP 7 cells were cultured
with the various sera, and after 7-14 days adipocytogenesis was determined by oil red O staining and lipoprotein lipase (LPL)
and glycerol 3-phosphate dehydrogenase (G3PDH) expression. Incubation with 10% premenopausal serum led to labeling of 10.9%
of cells (P<0.05) with oil red O, whereas application of 10% postmenopausal serum led to a much larger effect, 43.5% labeling (P<0.001 with respect to premenopausal serum). Oil red O positivity was accompanied by loss of type I collagen expression
and increased LPL and G3PDH expression. HRT did not reverse the adipocytogenic effect of postmenopausal serum. In conclusion,
serum from postmenopausal women contains factors that steer hOP 7 bone progenitor cells toward an adipocytic phenotype, irrespective
of HRT. The study suggests a role for serum factors in the development of fatty marrow in postmenopausal osteoporosis.
Lumiracoxib is a selective inhibitor of cyclooxygenase-2 (COX-2) approved for the relief of symptoms of chronic inflammatory conditions. The aim of this study was to evaluate the effects of this specific inhibitor of COX-2 as adjunctive treatment on induced periodontitis in rats. Periodontal disease was induced at the first mandibular molar of 60 rats. After 7 days, the ligature was removed and all animals were submitted to scaling and root planing (SRP) along with local irrigation with saline solution and were divided into 2 groups: SRP (n = 30)-received subcutaneous injections of 1 mg/kg of body weight/day of saline solution for 3 days and; SRP + L (n = 30)-received subcutaneous injections of 1 mg/kg of body weight/day of Lumiracoxib for 3 days. Ten animals in each group were killed at 7, 15, and 30 days. The histological description was performed and the histometric values were statistically analyzed. In Group SRP + L, the histometric analysis (0.58 ± 0.08, 0.64 ± 0.06, and 0.56 ± 0.10 mm(2)) showed less bone loss (p < 0.05) than Group SRP (1.52 ± 0.08, 1.55 ± 0.09, and 1.49 ± 0.24 mm(2)) at 7, 15, and 30 days, respectively. Within the limits of this study it can be concluded that subcutaneous application of specific inhibitor of COX-2 was a beneficial adjunctive treatment for periodontal diseases induced in rats.
Flurbiprofen, a nonsteroidal anti-inflammatory drug (NSAID), reduces bone resorption in periodontal disease. This therapeutic effect has been attributed to inhibition of prostaglandin synthesis. In view of the importance of carbonic anhydrase (CA) in bone resorption, we examined the CA-inhibitory properties of flurbiprofen using bovine and human CA II and compared them with those of acetazolamide and two other NSAIDs, ibuprofen and indomethacin. Flurbiprofen inhibited both human and bovine erythrocyte CA II but to a much lesser degree than acetazolamide. Ibuprofen and indomethacin were much less active in inhibiting CA II than flurbiprofen.
The effect of prostaglandin E2 (PGE2) on alveolar bone resorption was examined in 8-week old Wistar rats by histometric analysis. One mg/ml PGE2 topically applied to gingival sulcus induced a marked increase in osteoclasts. The number of osteoclasts increased progressively and reached a maximum at 12 hours. Ultrastructurally, these osteoclasts were in active form with well developed ruffled borders and clear zones. The changes in numbers of osteoclasts after application of various concentrations of PGE2 were dose-dependent (0.001 to 1.0 mg/ml), but higher concentrations of PGE2 (2 mg/ml) were less effective. In addition, the number of osteoclasts in groups treated with both PGE2 and endotoxin was higher than those that received PGE2 only. These results indicate that bone resorption caused by PGE2 depends on activation and increase of osteoclasts, and suggests that endogenous PGE2 production by host cells stimulated by plaque-associated bacterial endotoxin may be an important pathogenetic factor in periodontal disease.
The effect of dietary n-3 fatty acids on prostaglandin E2 (PGE2) and leukotriene C4 (LTC4) levels in rat salivary glands and gingiva was examined in two separate nutritional studies. In the first set of experiments, two groups of male weanling Sprague-Dawley rats were fed semipurified diets containing 10% corn oil (control group) or 10% menhaden oil (experimental group). Rats were killed after 8 wk on the diets; the fatty acid composition of total phospholipids and the concentrations of PGE2 and its precursor, arachidonic acid, were measured in gingiva and submandibular salivary glands (SMSG). Dietary n-3 fatty acids were incorporated into the tissue phospholipids. Arachidonic acid levels were reduced by 56% in gingiva and SMSG of rats fed menhaden oil compared with the control rats fed the diet containing corn oil. The concentrations of PGE2 in SMSG and gingiva of rats fed the diet containing menhaden oil were reduced by 74% and 83%, respectively. In a subsequent nutritional study, we tested whether the diet-induced reduction in tissue arachidonic acid levels would also result in a corresponding decrease in LTC4 production. Three groups of rats were fed diets containing 5% corn oil (group 1), 4% ethyl ester concentrate of n-3 fatty acids plus 1% corn oil (group 2), or 5% ethyl ester concentrate of n-3 fatty acids (group 3). After 6 wk of feeding, gingiva and SMSG were analyzed for arachidonic acid content and in vitro production of LTC4.(ABSTRACT TRUNCATED AT 250 WORDS)
A single-blind investigation was designed to study the effects of piroxicam in preventing gingival inflammation and plaque formation in beagle dogs. Twelve 1-year-old beagles were brought to optimum oral hygiene and gingival health. Thereafter, they were fed a moist plaque-promoting diet and were divided into three groups. The first group received daily administration of 1.0 ml placebo gel (methylcellulose) painted on the teeth. The second group received 1.0 ml of gel containing 2 mg/ml piroxicam and the third group received 1.0 ml liquid containing 2 mg/ml of piroxicam. Placebo and test solutions were applied daily, and dogs were examined biweekly for evaluation of plaque accumulation, gingival inflammation, bleeding upon gentle probing and tooth staining. Data were analyzed using the Krushkal-Wallis test. Over the treatment period, plaque accumulation was substantial in all three groups and was not significantly different between the three groups. By week 2, the gingival index in the piroxicam-treated dogs was significantly lower than that of the placebo-treated group and remained so throughout the study, with the exception of wk 6 and 12 in the topical gel-treated group. Mean percent bleeding sites were also significantly less in the piroxicam-treated groups than in the control dogs. Staining of the teeth increased for all groups over the 16-wk treatment period. These data indicate that piroxicam can significantly inhibit the development of gingival inflammation in beagle dogs.
Lipopolysaccharide (Y4 LPS) isolated from Actinobacillus actinomycetemcomitans strain Y4 induced bone resorption in BALB/c mouse calvaria organ culture. The calcium release from LPS-low responsive C3H/HeJ mouse calvaria by Y4 LPS was very low. Indomethacin almost completely inhibited prostaglandin E2 (PGE2) production by Y4 LPS-stimulated BALB/c mouse calvaria, but did not suppress interleukin-1 (IL-1) release from the calvaria, and partially suppressed the bone resorption. Dexamethasone strongly inhibited the PGE2 and IL-1 production by Y4 LPS-stimulated BALB/c mouse calvaria, as well as Y4 LPS-induced bone resorption. Dexamethasone inhibited expression of membrane IL-1 on osteoblastic cells stimulated with Y4 LPS, but indomethacin did not. Furthermore, anti-IL-1 serum partially suppressed the calcium release from Y4 LPS-stimulated BALB/c mouse calvaria. These results suggest that both PGE2 and IL-1 participate in Y4 LPS-induced bone resorption in vitro.
The non-steroidal anti-inflammatory drug(NSAID) naproxen was studied in 11 beagle dogs over a 13-month period to determine its effect on the progression of periodontitis. Following a 6-month pretreatment period, 5 dogs received naproxen daily at a dosage of 2.0 mg/kg for 1 month, then 0.2 mg/kg for 6 months. Six control dogs received a gelatin capsule daily as placebo. Standardized radiographs were used to measure the rate of bone loss during the pretreatment and treatment periods. In the control dogs, the rate of bone loss was seen to increase during the treatment period although the increase was not statistically significant. In dogs treated daily with naproxen, the rate of bone loss in the treatment period was significantly less at 4 months of treatment; however, at 7 months the difference, though lower than pretreatment rate, was not significant. When the percent change in rate of bone loss during the overall 7-month treatment period was compared with pretreatment rate, the control dogs demonstrated a 38% increase in rate of bone loss during the treatment period contrasting with a 61% decrease in bone loss rate in naproxen-treated dogs. The data indicate that the non-steroidal anti-inflammatory drug naproxen can significantly inhibit alveolar bone loss in beagles. At 4 months of treatment the rate of bone loss in the naproxen-treated dogs was significantly less than pretreatment, but at 7 months of treatment the rate was no longer statistically significantly less than baseline. This probably reflects a dose response to naproxen treatment for, after 30 days of the treatment period, the naproxen dosage was reduced 10-fold due to tolerance by the beagle.
Considerable evidence has demonstrated the importance of PGE2 synthesis in the pathogenesis of periodontal disease. Although various cyclooxygenase inhibitors have been known to block periodontal PGE2 synthesis and prevent disease progression in animal models, there are few reports comparing relative efficacies of various inhibitors of arachidonic acid (ARA) metabolism. We have developed a sensitive in vitro assay to measure PGE2 synthesis in periodontal tissues. The apparent IC50 values (i.e. the concentration of drug which causes 50% inhibition of maximum PGE2 synthesis) have been determined for a series of arachidonic acid analogues as well as competitive and non-competitive cyclooxygenase inhibitors. Periodontal tissue homogenates were incubated in the presence of 3H-arachidonic acid for 45 min at 37 degrees C. Inhibitors were tested at 10(-10)-10(-4) M and at zero concentration to measure conversion of 3H-arachidonate to 3H-PGE2. Log or half log dilutions of inhibitors were tested in triplicate for each assay. Radiolabeled PGE2 was extracted from homogenates, purified by reverse phase chromatography and quantitated by double antibody capture. RIA was performed on each homogenate to determine the amount of endogenous unlabeled PGE2 present in the sample to correct for antibody capture recovery. The apparent IC50 values were determined for each drug by averaging two or more replicate assays. Specific total enzymatic activity of periodontal tissue homogenates was typically 5-11 pg PGE2/min/mg tissue.(ABSTRACT TRUNCATED AT 250 WORDS)
The purpose of these experiments was to assess the role of the lipoxygenation products of arachidonic acid in hamster periodontitis. Phenidone and ketoconazole were used as inhibitors of leukotriene synthesis. In an established periodontitis, both drugs administered for 30 days induced a statistically significant decrease in PMNLs in the infiltrated connective tissue and around bacterial plaque within periodontal pockets. These changes were associated with a significant decrease in osteoclastic bone resorption. The results suggest that leukotrienes, and particularly leukotriene B4, are involved during hamster periodontitis and are responsible for PMNL infiltration of the periodontal pocket. The effects on bone are probably the consequence of the reduced inflammation resulting from the decrease in PMNL chemotaxis.
Bradykinin stimulated production of prostaglandin E2 (PGE2) and the release of 3H-arachidonic acid by gingival fibroblasts in a time- and dose-dependent manner. The effect on PGE2 biosynthesis was seen already after 15 seconds and was maximal after 5 minutes. Several structurally unrelated inhibitors of arachidonic acid metabolism via the cyclooxygenase pathway totally abolished the PGE2 response to bradykinin. The stimulation of PGE2 formation was seen at and above 10 nmol/l of bradykinin. Des-Arg9-bradykinin was 100-fold less potent compared to bradykinin. Des-Arg9-Leu8-bradykinin did not antagonize bradykinin-induced PGE2 formation. Met-Lys-bradykinin and Lys-bradykinin also enhanced PGE2 formation in gingival fibroblasts. The stimulatory action of bradykinin on 3H-arachidonic acid release was observed after 30 s and progressively increased for at least 15 min. The stimulatory effect on 3H-arachidonic acid release by bradykinin was seen at and above 10 nmol/l, whereas des-Arg9-bradykinin was without effect up to a concentration of 1 mumol/l. Indomethacin did not affect bradykinin-induced 3H-arachidonic acid release. These data show that bradykinin, via a B2-receptor-mediated pathway, can stimulate arachidonic acid release and subsequent prostanoid formation in gingival fibroblasts. Consequently, gingival fibroblasts may contribute, by a bradykinin-regulated reaction, to the enhanced amounts of prostanoids found in gingival tissues and crevicular fluids in patients with periodontal diseases.
The present study was undertaken to compare the periodontal status of a group of 50 patients on long-term non-steroidal anti-inflammatory drug (NSAID) therapy with that of an age and sex-matched group of 42 controls. The mean duration of drug therapy in the study group was 9 years (range 2-30 years). The clinical parameters investigated were plaque index (PI), gingival index (GI), pocket probing depth (PPD), loss of attachment (LOA), gingival recession (GR) and gingival fluid flow (GFF). Long cone periapical radiographs were also taken to score the amount of alveolar bone resorption. Examinations were carried out on 6 Ramfjord teeth in each subject. The results showed that there were no significant differences between the groups for PI, GI, PPD, LOA, GR or alveolar bone resorption. However, a highly significant difference was seen between the gingival fluid flow in the study (16.74 +/- 10.61) and control (37.72 +/- 28.63) groups (p less than 0.001). It is suggested that this may be associated with the specific effects of NSAIDs in reducing the vascularity and permeability of small blood vessels.
The four principal metabolites of cyclooxygenase (CO) were examined during the progression of experimental periodontitis in the rhesus monkey Macaca mulatta. Thirty-two monkeys were divided in four disease-matched groups. Three groups were treated with flurbiprofen, a potent CO inhibitor, at either 0.027, 0.27 or 7.1 mg/kg/day delivered systemically by a subcutaneously-implanted osmotic mini-pump. We have previously described the findings indicating that flurbiprofen treatment significantly retarded clinical attachment loss (ALOSS), redness and radiographic bone loss (BLOSS). This investigation focuses on the changes in CO metabolites which occur during disease progression of ligature-induced periodontitis and on the dose-response relationship of flurbiprofen, as it relates to disease inhibition and the suppression of ARA metabolites within the crevicular fluid (CF). In untreated animals there was a statistically significant 3-fold increase in CF levels of prostaglandin E2 (PGE2) and thromboxane B2 (TxB2) at 3 months, as compared to baseline, which positively correlated with increases in redness, bleeding, ALOSS and BLOSS. CF-PGE2 and TxB2 levels reached a 6-fold peak at 6 months and returned to baseline by 12 months. Flurbiprofen (Fb) prevented the 3-month rise in TxB2, but did not affect the increase in PGE2. At 6 months, Fb administration caused a dose-dependent inhibition of both PGE2 and TxB2. Probit analysis of the dose-response data revealed that the concentration of Fb which caused a 50% inhibition of CF-TxB2 level (the IC50 value for TxB2 synthesis) was approximately two logs lower than the IC50 value for PGE2 synthesis, i.e. TxA2-IC50 = 0.013 vs. PGE2-IC50 = 1.35 mg flurbiprofen/kg/d. The slopes of the PGE2 and TxB2 inhibition curves were identical, consistent with a similar mechanism or singular enzyme for the site of action of Fb inhibition of CO activity. However, the kinetics and sensitivity of Fb inhibition were significantly different for the CO activity responsible for TxB2 and PGE2 synthesis, perhaps due to different compartmentalization of CO within different cell types.
Thrombin and bradykinin stimulate production of prostaglandin E2 (PGE2), and 6-keto-prostaglandin F1 alpha (the stable breakdown product of prostacyclin) in isolated human peripheral blood monocytes in a dose- and time-dependent manner. Since PGE2 and prostacyclin can affect the activity of immunocompetent cells and bone resorbing osteoclasts, our finding indicates that thrombin and bradykinin, both of which are formed in inflammatory processes as a consequence of activation of the Hageman factor (coagulation factor XII), may have important roles in the modulation of the inflammatory response and the loss of alveolar bone in periodontitis.
The treatment of human periodontal diseases relies on mechanical and antimicrobial suppression of the etiologic bacteria. The ability to alter the progression of periodontitis by additionally blocking host pathways involved in the destructive process is an area of current research. Prostaglandins and other metabolites of arachidonic acid are believed to be important host mediators of the bone resorption of diseases such as periodontitis. We have previously examined the effect of inhibitors of prostaglandin production, non-steroidal anti-inflammatory drugs (NSAIDs), on inhibiting alveolar bone loss in beagles. The present study was designed to examine the effect of the NSAID, flurbiprofen, on slowing the radiographic loss of alveolar bone in the human. Fifty-six individuals with radiographic evidence of alveolar bone loss were recruited for study. Forty-four patients remained in the study for the data analysis of loss of alveolar bone. Following a 6 month baseline pretreatment period to measure the radiographic progression of bone loss, half of the patients were administered flurbiprofen, 50 mg. b.i.d., while half were administered a placebo. All patients received a subgingival scaling and pumice by a hygienist every 6 months. The rate of alveolar bone loss in a 2 year treatment period was compared to the baseline 6 month pretreatment period within and between patient groups. Throughout the study, teeth exhibiting obvious loss of bone were exited from study and treated with conventional mechanical therapy. At the end of the pretreatment period both patient groups had a similar mean rate of alveolar bone loss.(ABSTRACT TRUNCATED AT 250 WORDS)
24 healthy volunteers abstained from tooth-cleaning for 17 days. Parameters of gingival health were recorded on days 1 and 17. On days 4, 6, 8, 11, 13 and 15, each volunteer randomly received, on a double-blind basis, 100 ml of 10 mM flurbiprofen solution in buffered preservative to one upper quadrant of the mouth. The contralateral quadrant received preservative only. Applications were made using a pulsed jet irrigating system. Gingivitis developed in all patients and there were no significant differences between the treatments for gingival index or pocket probing depths. When gingival health was re-established, 4 volunteers had a further 3 irrigations of flurbiprofen at intervals of 2 days. Plasma levels of flurbiprofen were determined after the 1st and 3rd irrigations. Assays showed that the drug was present in the plasma of all 4 subjects (range 0.2-0.7 micrograms/ml). Gingival health was re-established in 6 further volunteers from the original study. They then abstained from toothbrushing for 17 days, during which one maxillary quadrant was irrigated with the buffered preservative solution. The irrigations were made on the same basis as in the original study. Gingivitis again developed in these quadrants, although when the results were compared to the equivalent data from the first investigation, significantly greater median values for probing pocket depths and gingival indices were found in the latter study. Therefore, it appears that systemic absorption of flurbiprofen may have reduced the severity of the developing inflammatory lesions.
Periodontal conditions among an adult population of 161 dentate patients with rheumatoid arthritis (RA) were compared with those of an age and sex-matched random sample of non-rheumatic subjects. The number of teeth and prevalence of dental plaque, calculus, gingivitis, and deepened periodontal pockets were recorded. Alveolar bone breakdown and the distribution of subjects according to severity of periodontal disease were also registered. There was a tendency towards better periodontal conditions among RA-patients, severe periodontal breakdown occurring less frequently among RA-patients (12%) than among the controls (16%). The RA-patients had less plaque and calculus than the control group, a finding which could indicate a difference in periodontal care.
The effect of two non-steroidal anti-inflammatory drugs, indomethacin and flurbiprofen, on the progression of periodontal disease was studied in 16 beagle dogs over a 12-month period. Standardized radiographs were used to measure the rate of bone loss. Following a 6-month pretreatment baseline period, 5 dogs were dosed daily with 1.0 mg/kg indomethacin, 5 dogs were dosed daily with 0.02 mg/kg flurbiprofen, and 6 dogs were dosed with empty gelatin capsules for a 6-month period. In the untreated control dogs, the rate of bone loss in the treatment period significantly increased from baseline. In contrast, the rate of bone loss significantly decreased from baseline in the flurbiprofen-treated dogs. In the indomethacin-treated dogs, rate of bone loss in the treatment period was not significantly different from baseline. The data indicate that both flurbiprofen and indomethacin inhibit alveolar bone loss in beagles compared to untreated controls. The data also indicate that with the dosages employed flurbiprofen is overall more effective.
The effect of the nonsteroidal anti-inflammatory drug flurbiprofen has been studied in the ligature-induced and spontaneous periodontitis model in the rhesus monkey, Macaca mulatta. Twenty-four adult monkeys with incipient periodontitis were divided into three disease-matched groups. Two groups received flurbiprofen at dosages of either 0.27 mg/kg/d or 7.1 mg/kg/d delivered systemically via osmotic minipump. A split-mouth approach was used, placing ligatures on one side and monitoring the progression of periodontitis at regular intervals for 6 months. Clinical measurements included standardized radiographs, Ramfjord attachment level determinations and assessments of redness, edema and bleeding on probing. There was a statistically significant inhibition of attachment loss (p < 0.05), gingival redness (p < 0.05) and bleeding on probing (p < 0.05) in ligatureinduced and spontaneous periodontitis in the flurbiprofen-treated animals at 6 months. Eight of 8 ligated control monkeys lost significant attachment (mean loss of 1.06 mm/site). Only 3 of 15 flurbiprofen-treated ligated monkeys lost any significant attachment, with an overall mean loss of 0.34 mm/site, which was significantly less than the control loss of 1.06 mm/site at p = 4.46 times 10-3. The odds of a control ligated monkey undergoing significant attachment loss in 6 months are elevated 29.3-fold, as compared to the flurbiprofen-treated, cohort monkey group. Flurbiprofen treatment also significantly inhibited spontaneous attachment loss for 6 months as compared to control monkeys, at p < 0.05. These data provide further evidence for the central role of cyclooxygenase products in the progression of periodontal disease. The ability of flurbiprofen to inhibit periodontal attachment loss, even in the presence of gross plaque accumulation, has significant implications for the potential use of flurbiprofen as an adjunctive periodontal therapeutic modality.
Paravascular distribution of fibroblastlike cells was determined, under conditions of arrested osteogenesis (resorbing or resting bone surface), in periodontal ligament (PDL) of maxillary first molars from 89-day-old male rats. As identified by nuclear volume, less differentiated precursor cells (A) and committed osteoprogenitor cells (A') were predominantly localized within 20 μm of the nearest major blood vessel (NMBV). G1 stage preosteoblasts (C cells) and G2 stage preosteoblasts (D cells) tended to be more numerous away from NMBV. Since the osteoblast (Ob) histogenesis sequence is A → A' → C → D → Ob, the present data were consistent with an osteogenic differentiation gradient radiating from blood vessels. It was concluded that preosteoblast formation (A' → C) occurs in a relatively low cell density (4–5 cells/1000 mm2) area ≥20 μm from NMBV. More than 30 μm from the vessel wall, C cells enter DNA synthesis and become D cells, which divide and migrate toward the bone surface, forming 2 osteoblasts each. This is the first integrated description of the cell proliferation differentiation and migration process associated with osteoblast histogenesis.
The effect of two non-steroidal anti-inflammatory drugs, indomethacin and flurbiprofen, on the progression of alveolar bone loss and on the crevicular fluid (CF) levels of four arachidonic acid metabolites was compared in 16 beagle dogs over a 12-month period. Standardized radiographs were used to measure the rate of bone loss. Radioimmunoassay was used to measure CF levels of PGE2, PGF2α, TxB2 and 6K-PGF1α. Following a 6-month pretreatment baseline period, 5 dogs were dosed daily with 1.0 mg/kg indomethacin, 5 dogs were dosed daily with 0.02 mg/kg flurbiprofen, and 6 dogs were dosed with empty gelatin capsules for a 6-month period. With the administration of either indomethacin or flurbiprofen. the CF levels of PGE2, PGF2α, and TxB2 were similarly significantly decreased; 6K-PGF1α levels were not altered. Indomethacin and flurbiprofen did not have a similar effect on reducing the rate of alveolar bone loss. Flurbiprofen significantly decreased rate of bone loss from baseline whereas indomethacin did not. The data indicate that indomethacin and flurbiprofen inhibit CF arachidonic acid metabolite levels in a similar manner, but not rate of bone loss. The data suggest that flurbiprofen's striking effect on inhibiting rate of bone loss cannot be solely attributed to simple cyclooxygenase inhibition with a reduction in CF prostaglandin levels.
The effect of the non-steroidal anti-inflammatory drug flurbiprofen, topically applied, on the progression of periodontal disease was studied in 12 beagle dogs over a 13-month period. Standardized radiographs were used to measure the rate of bone loss. Following a 6-month pretreatment baseline period, 6 dogs were treated daily with 0.3 mg flurbiprofen gently applied to the gingival margin in 1 ml of gel vehicle. Six untreated dogs served as controls. In the untreated control dogs the rate of bone loss in the treatment period did not change significantly from baseline, although the rate was elevated by 38%. In contrast, the rate of bone loss significantly decreased by 71% from baseline in the flurbiprofen-treated dogs. The untreated control dogs lost 10 teeth during the treatment period whereas the topical flurbiprofen-treated dogs lost only 1 tooth. The data indicate that topical application of flurbiprofen in a gel vehicle significantly inhibits alveolar bone loss in beagles over a 7-month treatment period. The data also indicate that topical flurbiprofen is associated with the loss of considerably less teeth than in untreated control dogs over the 7-month treatment period.
The effect of the non-steroidal anti-inflammatory drug, ibuprofen, on the progression of periodontal disease was studied in 22 beagle dogs over a 13-month period. Standardized radiographs were used to measure the rate of bone loss. Following a 6-month pretreatment baseline period. 6 dogs were treated daily with 4 mg/kg ibuprofen, 5 dogs were treated with 4 mg/kg ibuprofen in a sustained release preparation, 5 dogs were treated with 0.4 mg/kg ibuprofen and 6 untreated dogs served as controls. In the untreated control dogs the rate of bone loss in the treatment period did not change significantly from baseline, although the rate was increased. In both the 4.0 mg/kg and sustained release 4.0 mg/kg ibuprofen-treated dogs the rate of bone loss in the treatment period was significantly less than the pretreatment period rate. In the 0.4 mg/kg ibuprofen-treated dogs the rate of bone loss, although reduced, was not significantly less than the pretreatment rate. When the rate of bone loss in the control dogs was compared with the rate of bone loss in the ibuprofen-treated dogs, all three ibuprofen-treated groups of dogs had significantly less bone loss than the control dogs. The untreated control dogs lost 10 teeth during the treatment period, whereas the 4.0 mg/kg and 0.4 mg/kg ibuprofen-treated dogs lost 6 teeth and the sustained release 4.0 mg/kg ibuprofen-treated dogs lost 2 teeth during the treatment period. The data indicate that a propionic acid derivative, the non-steroidal anti-inflammatory drug, ibuprofen, can significantly inhibit alveolar bone loss in beagles. Sustained release ibuprofen. which gave consistently greater blood levels over 24 h, was overall more effective.
Periodontitis constitutes a major cause of tooth loss, particularly in older age-groups. The aetiology and pathogenesis of the disease are relatively well established, and the timehonoured treatment methods are time consuming, both for the profession and their patients.This article reviews some current views on the mediators of periodontal disease, especially the role of prostaglandins and other eicosanoids. It then provides evidence that non-steroidal anti-inflammatory drugs may have an important application in controlling the progression of the disease, both in experimental animal models and humans.
The periodontium and periodontal disease activity can be affected by systemic drug therapy. Many drugs can have an adverse effect on the periodontium, i.e., gingival hyperplasia. Alternatively, some drugs can modify the inflammatory and immunological responses of the periodontal tissues to bacterial plaque. The aim of this review is to evaluate the effects of drug therapy on the periodontium and periodontal disease activity, and where possible, to relate such changes to the pharmacodynamics of the drugs considered. Drugs which have been reported to affect the periodontium can be categorised as follows: anti-epileptics, immunosuppressants, corticosteroids, non-steroidal anti-inflammatory drugs and hormones. Those drugs whose pharmacodynamics are clearly established and which affect the rate of periodontal disease activity, may provide information on the mechanisms of periodontal destruction. Finally, the mechanisms of drug-induced gingival hyperplasia (overgrowth) are discussed in relationship to the drugs' pharmacodynamics and pharmacokinetics.
Prostaglandins are believed to be important mediators of periodontal inflammation and bone resorption. The purpose of the present blind study was to quantify clinically and histologically the effects of a topically applied nonsteroidal prostaglandin synthetase inhibitor, namely a substituted oxazolopyridine derivative (SOPD), on ligature-induced periodontal disease in the squirrel monkey. For a period of 14 days, one group of ligated animals received 2 daily topical applications of the SOPD. A group receiving systemically administered indomethacin served as a positive control while a group receiving only topically applied vehicle served as a negative control. Results indicate that throughout the 14-day period of the study, the SOPD significantly inhibited gingival inflammation and loss of attachment as compared to either the placebo or indomethacin groups. Both indomethacin and the SOPD significantly inhibited bone resorption.
The osteoclast may play an important rŏle in the variable rate of osseous destruction seen in periodontitis. Current understanding of various aspects of the osteoclast may help explain this fact. This review paper will first look at two theories of cell origin of the osteoclast: the multipotential osteoprogenitor cell theory and the hemopoietic stem cell theory. Next, ultrastructural features characteristic to the cell such as the ruffled border, clear zone, and lysosomal system, will be discussed. Thirdly, current and proposed theories on the actual mechanism of bone degradation are considered. This includes the one-cell theory and the two-cell theory. Finally, elements which activate the osteoclast are enumerated and their delicate interplay is outlined. In the context of this information, pathways found in the periodontal lesion (microbial agents, inflammatory cells and their products) which attract and activate elements of the osteoclastic system are discussed.
The influence of acetylsalicylic acid (ASA) (150 mg/kg/12 h) and naproxen (20 mg/kg/12 h) on bone metabolism in young male rats has been studied. The doses were chosen to provide serum concentrations comparable with ordinary anti-inflammatory steady-state levels in humans. After the rats had been prelabeled with collagen- and mineral-tracing radioisotopes the rats received the drugs by gavage twice a day for 9 and 18 days. Bone resorption was measured as loss of carbon-labeled hydroxyproline (collagen) and strontium-85 (minerals). At 9 days ASA had retarded both collagen and mineral resorption in the femur by about 10% compared with controls. The resorption of both collagen and minerals was inhibited. After 18 days' treatment there were no differences regarding bone resorption, but bone formation had decreased by about 10% in the ASA-treated animals, as measured by net increases of collagen and calcium in the femur. Naproxen did not influence bone resorption or formation significantly. The results indicate an inhibitory effect of ASA on bone resorption and formation in growing rats, whereas the effect of naproxen seems negligible.
A transplantable mouse fibrosarcoma, HSDM1, produces a potent bone resorption-stimulating factor. The factor can be extracted from the tumor tissue and harvested from the medium of clonal strains of HSDM1 tumor cells growing in monolayer culture. It has several chemical and biological properties of a prostaglandin. Using radioimmunoassay techniques, we have shown that HSDM1 cells synthesize and secrete large quantities of prostaglandin E2 (PGE2). The specific bone resorption-stimulating activity of the HSDM1 factor extracted from the tumor is high and approximately equal to that of PGE2 as measured in a bone tissue culture system in vitro. Indomethacin, a potent inhibitor of PGE2 synthesis in HSDM1 cells, also inhibits production by the cells of the bone resorption-stimulating factor, and has no detectable nonspecific effects on the bone culture assay system. Mice bearing the HSDM1 tumor have higher levels of both calcium and PGE2 in serum than control mice. We conclude that PGE2 is the bone resorption-stimulating factor produced by HSDM1 tumor cells, and that secretion of PGE2 by the tumor in vivo accounts for the relative hypercalcemia observed in tumor-bearing animals. The HSDM1 tumor cell system constitutes a new model for studying the pathogenesis of hypercalcemia associated with certain malignant tumors.
Periodontal diseases are multifactorial, caused by polymicrobial subgingival pathogens, including Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia. Chronic periodontal infection results in inflammation, destruction of connective tissues, periodontal ligament, and alveolar bone resorption, and ultimately tooth loss. Enoxacin and a bisphosphonate derivative of enoxacin (bis-enoxacin) inhibit osteoclast formation and bone resorption and also contain antibiotic properties. Our study proposes that enoxacin and/or bis-enoxacin may be useful in reducing alveolar bone resorption and possibly bacterial colonization. Rats were infected with 109 cells of polymicrobial inoculum consisting of P. gingivalis, T. denticola, and T. forsythia, as an oral lavage every other week for twelve weeks. Daily subcutaneous injections of enoxacin (5 mg/kg/day), bis-enoxacin (5, 25 mg/kg/day), alendronate (1, 10 mg/kg/day), or doxycycline (5 mg/day) were administered after 6 weeks of polymicrobial infection. Periodontal disease parameters, including bacterial colonization/infection, immune response, inflammation, alveolar bone resorption, and systemic spread, were assessed post-euthanasia. All three periodontal pathogens colonized the rat oral cavity during polymicrobial infection. Polymicrobial infection induced an increase in total alveolar bone resorption, intrabony defects, and gingival inflammation. Treatment with bis-enoxacin significantly decreased alveolar bone resorption more effectively than either alendronate or doxycycline. Histologic examination revealed that treatment with bis-enoxacin and enoxacin reduced gingival inflammation and decreased apical migration of junctional epithelium. These data support the hypothesis that bis-enoxacin and enoxacin may be useful for the treatment of periodontal disease.
Osteoclast-activating factor (OAF), a powerful stimulator of osteoclastic bone resorption, is released by peripheral blood mononuclear cells on exposure to phytohemagglutinin (PHA) or a specific antigen to which the leukocytes have been previously exposed. Both lymphocytes and monocytes are required in the leukocyte population for OAF release to occur. In this study we examined the relationship between the lymphocyte and monocyte in OAF production. Biological activity, as a result of OAF, was assessed by a bioassay based on the release of previously incorporated 45Ca from fetal rodent long bones in organ culture. We found that an enriched lymphocyte population depleted of monocytes by serial adherence does not release OAF after stimulation with PHA, although the cells are activated as assessed by [3H]thymidine and 3H-amino acid incorporation. When conditioned media harvested from adherent cells which did not contain OAF was added to the enriched lymphocytes, OAF release occurred. Media harvested from adherent cells which were cultured with indomethacin (10 microM), an inhibitor of prostaglandin synthesis, did not permit OAF release by activated lymphocytes. When PGE1 and PGE2 (0.1 microM) were added exogenously to the enriched lymphocyte population, OAF release occurred after stimulation with PHA. These results indicate that, (a) the activated lymphocyte is the cell or origin of OAF, (b) prostaglandins produced by monocytes are necessary for OAF production by activated lymphocytes, and (c) monocyte prostaglandins can influence bone resorption indirectly by regulating OAF production as well as directly by osteoclast activation. The interactions of OAF and prostaglandins at bone resorbing sites may be important in inflammatory and neoplastic diseases associated with bone destruction.
Purified populations of both human peripheral blood monocytes and murine peritoneal macrophages synthesize and release Prostaglandin E in vitro. In contrast, prostaglandin E was detected in neither the supernate fluids from cultures of highly enriched human lymphocytes and granulocytes, nor in nonadherent murine peritoneal cells. Macrophage prostaglandin E production was markedly enhanced by endotoxin, and completely suppressed by indomethacin. All neoplastic monocyte-macrophage cell lines examined elaborated prostaglandin E in vitro, either constitutively or after induction with endotoxin. In contrast, prostaglandin E production could not be detected from either a T- or B-cell lymphoma, whether or not they were treated with endotoxin. These findings thus indicate that the blood monocyte and tissue macrophage represent an important source of prostaglandin E, a function shared by both normal and neoplastic mononuclear phagocytes.
In the use of anti-inflammatory compounds, sustained serum levels are thought to be related to drug efficacy. This study shows that frequent clinical administration of indomethacin can result in sustained serum levels of the drug and that food and antacid may have important modifying effects on serum indomethacin concentrations. After oral ingestion by fasting subjects, indomethacin rapidly appeared in the serum, usually reaching peak concentrations in 30 to 90 minutes. Food delayed and decreased the mean peak level; antacid delayed the peak and slightly enhanced subsequent concentrations. With multiple dose schedules plateau levels were reached after 24 hours. When a total daily dose of 150 mg was given as 25 mg every 4 hours peak concentrations were the same but fluctuations were smaller and average concentrations were higher than with a dosage of 50 mg every 8 hours.
A transplantable mouse fibrosarcoma, HSDM(1), produces a potent bone resorption-stimulating factor. The factor can be extracted from the tumor tissue and harvested from the medium of clonal strains of HSDM(1) tumor cells growing in monolayer culture. It has several chemical and biological properties of a prostaglandin. Using radioimmunoassay techniques, we have shown that HSDM(1) cells synthesize and secrete large quantities of prostaglandin E(2) (PGE(2)). The specific bone resorption-stimulating activity of the HSDM(1) factor extracted from the tumor is high and approximately equal to that of PGE(2) as measured in a bone tissue culture system in vitro. Indomethacin, a potent inhibitor of PGE(2) synthesis in HSDM(1) cells, also inhibits production by the cells of the bone resorption-stimulating factor, and has no detectable nonspecific effects on the bone culture assay system. Mice bearing the HSDM(1) tumor have higher levels of both calcium and PGE(2) in serum than control mice. We conclude that PGE(2) is the bone resorption-stimulating factor produced by HSDM(1) tumor cells, and that secretion of PGE(2) by the tumor in vivo accounts for the relative hypercalcemia observed in tumor-bearing animals. The HSDM(1) tumor cell system constitutes a new model for studying the pathogenesis of hypercalcemia associated with certain malignant tumors.
A Clinical Trial in Hodgkin's Disease Relapse-free Survival Curves A Significance Test for Censored Data Comments Summary of Statistical Concepts Supplementary Problems
WHEN macrophages encounter inflammatory stimuli either in vivo or in vitro, they respond by releasing a number of products which may account for the central role that this cell has in chronic inflammatory diseases1. These products include hydrolytic enzymes active at neutral2 or acidic pH (ref. 1), components of both the classical3 and alternate pathway4 of complement, factors modulating responses of lymphocytes to antigens and mitogens5, and factor(s) influencing the proliferation6 and synthesis of collagen7 by fibroblasts. We now show that macrophages whose phospholipid components were labelled with 3H-arachidonic acid also synthesise and release 3H-prostaglandins (PGs) in response to inflammatory stimuli. These observations are consistent with the findings that human macrophages on intrauterine devices8 and guinea pig macrophages responding to lymphokines9 release PGs.
A study was designed to enumerate cell populations before, during and after experimentally induced periodontitis in squirrel monkeys. The clinically healthy gingival connective tissue adjacent to the sulcus contained populations of macrophages, plasma cells, lymphoid cells, and granulocytes, indicating that immune responses were probably in operation. Although these cell populations have been associated with tissue destruction, it is possible that they may serve to confine the antigens to the tissue adjacent to the sulcus, and reduce their spread apically. Active periodontitis was associated with the presence of granulocytes and macrophages in the transseptal fiber region. These cells are capable of causing the localized collagen degradation and bone resorption that occur during the destructive phase of the disease. Eight weeks after etiologic agents were removed, the cell populations in the transseptal fiber area returned to a level comparable with those in the pre-experimental, clinically healthy. This indicates that active periodontitis within the transseptal fiber region had ceased and repair had occurred.
A simple and inexpensive instrument called a longitudimeter for measuring distances in microscopy was constructed from a precision map-measuring device and an electric lamp positioned eccentrically on a stand. A precision better than 1% was readily obtained in measurements of the perimeters of trabecular surfaces in cancellous bone.
Mixed-image longitudimetry was devised for length measurements in cancellous bone, but the method seems suitable for a wider application in quantitative microscopy.
The placement of silk ligatures around the necks of teeth and into the gingival sulcus causes a rapid, acute inflammatory response leading to vigorous osteoclastic resorption of alveolar crestal bone. Associated with the large numbers of osteoclasts are mononuclear cells, predominantly fibroblast-like cells and macrophages. Some fibroblast-like cells contain intracellular collagen fibrils. It is suggested that in periodontal disease these mononuclear cells may compliment the action of osteoclasts by ingesting and degrading matrix molecules mobilized from bone but not ingested or degraded by osteoclasts.
Yersinia pestis plague murine toxin has been found to inhibit the mobilization of free fatty acids in mice in a manner similar to that of beta-adrenergic blocking agents. The blockage is detectable 75 min after injection of the toxin (1 to 2 mean lethal doses). The degree of inhibition was directly correlated with the toxicity of a given toxin preparation. Agents such as cholera toxin or glucagon, with apparently distinct receptors from beta-adrenergic receptors, stimulated adenylate cyclase and lipolysis and effectively modified toxicity. Likewise, cyclic adenosine 3',5'-monophosphate bypassed the toxin block and antagonized toxicity. Energy-rich compounds such as fatty acids, organic acids, and glucose effectively modified the intoxication process. The biological activity of plague toxin showed profound temperature sensitivity. Mice placed at 5 degrees C were highly susceptible to the effects of the toxin, whereas mice placed at 37 degrees C were totally resistant to intoxication. Results showed that plague toxin cannot block epinephrine-induced mobilization of free fatty acids in mice placed at 37 degrees C. These studies suggested that plague toxin acts at the receptor level in a manner similar to that of beta-adrenergic blocking agents. A complete, analogous activity was shown between toxin and known beta-adrenergic antagonists in their effect on beta-adrenergic agonist action in stimulating lipolysis. It is hypothesized that, since toxin shows no in vitro activity, it is in some way modified in animals.
1. The placement of cotton floss ligatures in a position apical to the gingival margin of premolars and molars in young dogs induced an acute inflammatory reaction in the periodontal tissues resulting in loss of connective tissue attachment and alveolar bone. 2. Bone resorption could be observed histologically within 7 days, and radiographically within 2 to 3 weeks after ligature placement. 3. Daily administration of indomethacin interfered with the periodontal tissue response to ligature placement. Indomethacin was shown to (i) delay the onset and to suppress the magnitude of the acute inflammatory reaction, and (ii) decrease the degree of alveolar bone resorption.
Prostaglandin synthesis by fetal rat bones was examined by thin-layer chromatography of culture media after preincubation with labeled arachidonic acid. Cultures in rabbit complement (non-heat inactivated serum) were compared with cultures in heat-inactivated serum or cultures treated with indomethacin. The major complement-dependent products were PGE2, PGF2 alpha and 6-keto-PGF1 alpha, the metabolite of prostacyclin (PGI2). Since PGI2 had not been previously identified in bone its ability to stimulate bone resorption was tested. Repeated addition of PGI2 stimulated release of previously incorporated 45Ca from fetal rat long bones in both short-term and long-term cultures at concentrations of 10(-5) to 10(-9)M. Because of the short half life of PGI2 in solution at neutral pH, we tested a sulfur analog, thiaprostacyclin (S-PGI2) which was found to be a stimulator of bone resorption at concentrations of 10(-5) to 10(-6)M. These studies suggest that endogenous PGI2 production may play a role in bone metabolism. Since vessels produce PGI2 it is possible that PGI2 release may be responsible for the frequent association between vascular invasion and resorption of bone or calcified cartilage in physiologic remodeling and pathologic osteolysis.
Cultured rabbit alveolar macrophages, prelabeled with 14C-arachidonic acid (AA), released into the medium a trace amount of labeled prostaglandins (PG) as well as their precursor, AA. Phagocytosis of zymosan, heat-killed Staphylococcus, or bacille Calmette-Guérin (BCG) increased the AA and PG release to 2--2.5 times control values. The released PGs consisted of PGE2, D2, F2 alpha, and 6-keto F1 alpha. Phagocytosis of latex particles had no effect on PG release. Indomethacin inhibited release of PGs but did not affect AA release at low doses. Analysis of the cellular lipids showed that zymosan decreased the radioactive label in phosphatidylcholine (PC), but not in other phospholipids or neutral lipids, suggesting that PC is the main source of AA for PG synthesis in pulmonary macrophages. Cytochalasin B (CB) at phagocytosis-inhibiting doses or below, markedly increased PG synthesis by zymosan-treated macrophages. These data suggest that PG release is not dependent on engulfment of the particles. Phagocytosis of zymosan (but not latex) also resulted in the release of two lysosomal enzymes, acid phosphatase and beta-glucuronidase, which appeared temporally associated with the release of PGs (but not to phagocytosis). Furthermore, CB augmented the zymosan-stimulated release of these enzymes at the same doses stimulating PG synthesis. However, indomethacin, at a dose completely inhibiting PG synthesis, failed to block lysosomal enzyme release. Thus, the coincidental release of PGs and lysosomal enzymes is not the result of a regulatory role of PGs in the release of lysosomal enzymes, but probably is the result of a common pathway of stimulation. (Am J Pathol 97:137--148, 1979).
Ultrastructural observations on macrophage-mediated resorption of calcified tissue of killed fetal long bones are described and correlated with increased 45Ca release into the medium. Macrophages disrupt calcified tissue extracellularly and appear to engulf large fragments of mineralized matrix. Ruffled borders, which are common features of osteoclasts at sites of resorption of bone, do not develop in macrophages. However, clear zones are seen in macrophages as well as osteoclasts. These findings provide additional evidence for non-osteoclast-mediated resorption of calcified tissue.
Osteoclastic bone resorption involves the solubilization of the mineral salts and the degradation of noncollagen bone matrix and collagen fibrils. As no recognizable collagen fibrils have ever been reported within cytoplasmic vacuoles in osteoclasts, it is generally assumed that the collagen fibrils are digested extracellularly in the resorption zone. The extent to which lysis occurs extracellularly and whether or not the osteoclasts phagocytose the degradation products remain to be established.
In the present communication, a hypothesis is presented suggesting the possibility that osteoclastic resorption of bone involves the participation of two different cell types. According to this hypothesis, osteoclastic bone resorption is initiated by osteoclasts that demineralize areas of bone and degrade noncollagen bone matrix. After the osteoclasts have moved away or become partially detached from the demineralized site, the exposed collagen fibrils are phagocytosed by mononuclear, fibroblast-like or monocyte-derived cells.
Chronic periodontitis, a common disease of microbial origin, is the major cause of tooth loss in adult humans. The disease serves as a convenient experimental model for analysis of many aspects of chronic inflammation. A consideration of currently available data has permitted the formulation of a new concept of the pathogenesis of this disease. The gingival tissues respond within 2 to 4 days to a beginning accumlation of microbial plaque with a classic acute exudative vasculitis which we have termed the initial lesion. This response, which includes loss of perivascular collagen, is comparable to that elicited in most other tissues subjected to acute injury and may be a consequence of the elaboration and release of chemotactic and antigenic substances by microbial plaque. Within 4 to 10 days, the early lesion develops. It is characterized by a dense infiltrate of lymphocytes and other mononuclear cells, pathologic alteration of fibroblasts, and continuing loss of the connective tissue substance. The structural features of the early lesion are consistent with those expected in some form of cellular hypersensitivity, and a mechanism of this kind may be important in the pathogenesis. The early lesion is followed by the established lesion which develops within 2 to 3 weeks and is distinguished by a predominance of plasma cells in the absence of significant bone loss. The established lesion, which is extremely widespread in humans and in animals, may remain stable for years or decades, or it may become converted into a progressive destructive lesion. Factors causing this conversion are not understood. In the advanced lesion, plasma cells continue to predominate although loss of the alveolar bone and periodontal ligament, and disruption of the tissue architecture with fibrosis are also important characteristics. The initial, early, and established lesions are sequential stages in gingivitis and they, rather than the advanced lesion which is manifest clinically as periodontitis, make up the major portion of inflammatory gingival and periodontal disease in humans.
When repetitive mechanical injury was produced in combination with marginal periodontitis a significant loss of connective tissue attachment did not occur as compared with specimens in which periodontitis alone was produced. It seems unlikely, therefore, that there is a "co-destructive" factor effect on the loss of connective tissue attachment. The amount of alveolar bone lost as a result of marginal periodontitis was increased by the addition of repeated mesiodistal jiggling of the teeth. This could represent an irreversible "co-destructive" effect or could merely be a functional adaptation of the periodontium.
Current concepts of the pathogenesis of periodontal disease, to a large degree, are based upon observations from light and electron microscopic preparations from normal and inflamed gingival tissues. It has been well documented that the established lesion of chronic gingivitis is distinguished by localized inflammatory infiltrates with plasma cells predominating. Chronic gingivitis always seems to be present, at least on the histologic level. However, it is not understood how such a localized gingival inflammation may be converted into a progressive, destructive periodontitis. Placement of silk ligatures in animal models at the gingival margins of teeth facilitates plaque accumulation and leads to marginal periodontitis, with loss of connective tissue attachment and loss of alveolar bone. Therefore, it was decided to study in 8 young adult squirrel monkeys, the cellular changes in the development and progression of this experimental marginal periodontitis. These experiments led to the following conclusions. Acute exacerbation of gingivitis can lead to destructive periodontitis. Such periods of acute inflammation may be associated with epithelial ulceration. Bone loss in periodontal disease may occur in bursts of osteoclastic activity triggered by cells or factors generated during an acute phase. Partial repair can follow an acute episode and a 'stable lesion' may become re-established.
In this study of monkeys histologic periodontal destruction was produced by a combination of inflammatory and traumatic factors. Trauma superimposed upon established marginal periodontitis resulted in greater alveolar bone loss compared with periodontitis alone. When the trauma was subsequently discontinued in this situation, the increased amount of bone loss was not reversible. This finding indicated that either the increased bone loss due to periodontitis plus trauma was not reversible or the presence of an existing marginal inflammation in the supracrestal connective tissue had an inhibitory effect upon any potential for bone regeneration. The purpose of this investigation was to resolve this question by studying alveolar bone behavior after removal of both the traumatic as well as the inflammatory factor. It appeared that after the inflammation was resolved and the trauma stopped, a significant amount of alveolar bone regeneration took place. The implications of these findings for the management of advanced periodontal disease are discussed.
Recent findings on the ultrastructure of the osteoclast indicate that special attention should be given to the ruffled border, clear zone, and the vacuoles and vesicles of the cell and their significance for the mechanism of breakdown of bone matrix. The ruffled border is seen as an extensive area of cell surface where secretion of enzymes as well as uptake of matrix components takes place. The clear zone encircles the ruffled border completely and thus forms an integral part of the resorbing apparatus. Vacuoles and vesicles are thought to secret enzymes as well as take up extracellular material and possible digest or transport these products in the cell. The changes that occur in the ultrastructure of the osteoclast after exposure to parathyroid hormone and calcitonin indicate an important role of the ostioclast in bone metabolism. The cell can increase its activity very rapidly in response to parathyroid hormone, and decrease its activity in response to calcitonin.
Activation of C by immunoglobulins reactive with cell surface antigens stimulated synthesis of prostaglandin E and resultant release of 45Ca from organ cultures of fetal rat bones labeled in utero. Absorption of the C source (rabbit serum) with rat spleen cells or dilution of C abolished this activity which was, however, restored by addition of immunoglobulin preparations from sera of rabbits immunized with either rat erythrocytes or sonicated fetal rat bones. The active reconstitution factors were present in the 50% (NH4)2SO4 cut of the antisera and were eluted from Sephadex G-200 in both the 19S and 7S fractions and from DEAE cellulose in the IgG-containing fraction. The C-dependent resorption of bone by the F(ab')2 fragments of the IgG antibody implicated a role for the alternative C pathway in this event. Complete inhibition of this biologic effect by indomethacin and detection of enhanced levels of prostaglandin E in the media of cultures containing antibody and C demonstrated a role for prostaglandins as mediators in the destruction of bone initiated by immune activation of C.
Prostaglandin E 1 is chemotactic at concentrations down to 10 ng/ml for rabbit polymorphonuclear (PMN) leucocytes. Prostaglandins E 2 and F 2α have little or no chemotactic effect at concentrations up to 10 μg/ml.
Washed PMN leucocytes produce a chemotactic agent during phagocytosis, but not in the presence of indomethacin (28 μM).
Phagocytosing PMN leucocytes produce up to ten times as much prostaglandin as do resting cells. Some of this is prostaglandin E 1 as judged by thin layer chromatography and differential bioassay. This prostaglandin production by PMN leucocytes is abolished by indomethacin (28 μM).
Ultrasonicated suspensions of PMN leucocytes produce prostaglandin from arachidonic acid. This synthesis is inhibited by indomethacin.
Homogenates of PMN leucocytes which have been pre‐incubated with bacteria for 30 min show more prostaglandin synthetase activity than homogenates from PMN leucocytes which have not been exposed to bacteria.
It is concluded that in some forms of inflammation, prostaglandin E 1 may play a controlling role in cellular migration.
PMN leucocytes may contribute to the generation of prostaglandins found in some inflammatory lesions.
The ability of E, F, A and B prostaglandins to stimulate bone resorption was demonstrated in organ culture. All of the compounds tested were able to increase the release of previously incorporated 45Ca from fetal rat bone by 60 to 135 per cent at maximally effective doses, but prostaglandins of the E series were 10- to 100- fold more potent than F, A or B prostaglandins. Compounds with two double bonds in the side chain were usually more potent than those with one double bond. PGE2 stimulation of bone resorption increased linearly with the logarithm of the medium concentration over the range of 10(-9)M to 10(-5)M, then decreased at higher concentrations. PGE2 stimulated bone resorption more slowly than did parathyroid hormone but caused complete resorption after six days in the culture system. Equilibrium dialysis studies showed no significant binding of F, and 16-34% binding of E and A prostaglandins to bovine serum albumin, which was present in the medium at 1 mg/ml. These differences in albumin binding could not account for differences in potency.
Indomethacin increases the cellular levels of several lysosomal enzymes in cultures of mouse peritoneal macrophages exposed to the drug for periods of time ranging from one day to four weeks. This increase can be blocked by puromycin, an inhibitor of protein synthesis. Pretreatment of macrophages with indomethacin inhibits the selective release of lysosomal enzymes induced by a C-mucopolysaccharide peptidoglycan complex purified from the cell walls of Group A streptococci.
Within the conditions of the experimental design, this study has provided laboratory evidence that microorganisms were necessary for the occurrence of inflammatory periodontal disease. Furthermore, this investigation has shown that the presence of both local irritation and microorganisms was necessary to produce periodontal inflammation. However, neither factor alone was capable of producing the inflammation. The results of this study have shown that a type of dental calculus may be formed in the absence of microorganisms. However, the same results have demonstrated that the presence of microorganisms greatly facilitates the formation of calculus. The presence of polymorphonuclear leukocytes in the gingival crevices and tissues could not be explained on the basis of bacteria and/or irritation. It was postulated that these cells are a normal component of the gingival tissues of these animals and that their presence does not constitute a pathologic process. The findings of the present study were considered with those of other studies. From this comparison it was suggested that differences in animal species and strains should be considered when evaluations and extrapolations of experimental results are made.
Prostaglandin E2 (10−6 to 10−4 M) inhibited incorporation of labeled proline into collagenase digestible protein, but not noncollagen protein, in calvaria of 21-day fetal rats cultured in a chemically defined medium for 24 hours. This effect did not occur immediately, was not abolished by adding cold proline to the medium, and was not associated with increased loss of collagen from the bone. Prostaglandin E1 was less effective while F, A, and B prostaglandins were ineffective or caused nonspecific inhibition of both collagen and noncollagen protein synthesis.
In an effort to describe the mechanism of bone erosion in patients with multiple myeloma, supernatant fluids from the short term cultures of bone marrow aspirated from seven patients with myeloma were examined. Six contained a factor that stimulated osteoclastic bone resorption (calcium release greater than controls) in organ culture. This factor was biologically and chemically similar to osteoclast activating factor, a mediator produced by phytohemagglutinin activated normal peripheral blood leukocytes. Cultures of bone marrow cells obtained from seven other patients with a variety of hematologic disorders did not produce a stimulator of bone resorption. Morphologic examination of autopsy and biopsy samples of bone from 37 patients with myeloma showed osteoclasts on bone resorbing surfaces adjacent to areas of heavy myeloma cell infiltration. It is suggested that osteolytic bone lesions and hypercalcemia in myeloma are due to the secretion of a soluble factor by myeloma cells that in turn stimulates osteoclastic activity in adjacent bone.
Complement-sufficient heterologous serum induced prostaglandin synthesis and resultant resorption in cultures of fetal rat
long bones. Bone resorption was enhanced with unheated normal rabbit serum as compared to heated serum or serum from rabbits
lacking the sixth component of complement (C6). Addition of functionally purified C6 restored resorptive activity in C6-deficient
serum. Concentrations of prostaglandin E were increased in the culture media of bones incubated with complement-sufficient
serum. The resorptive effects of active serum as well as the appearance of prostaglandin E in the media were inhibited by
indomethacin.
A new soluble mediator was found in supernatant fluid from cultures of human peripheral blood leukocytes that were stimulated
by phytohemagglutinin, or by antigenic material present in human dental plaque deposits. This soluble Jactor produced bone
resorption in organ cultures of fetal rat bones as measured by increased release of calcium-45, and also increased the number
of active osteoclasts.
Experiments with guinea-pig lung suggest that some of the therapeutic effects of sodium salicylate and aspirin-like drugs are due to inhibition of the synthesis of prostaglandins.
Twenty-four beagle dogs were divided into three groups of eight dogs each. Periodontitis was induced in three of the denial quadrants of each dog using wire ligatures while one quadrant was not ligaled and was kept cleaned. One group of dogs received no additional treatment, one group received systemic metronidazole and the third group received systemic indomethacin. The in vitro bone resorbing activity of extracts from freeze dried gingiva from the groups was compared.
Extracts of gingiva from ligaled teeth produced significant bone resorption. Metronidazole treatment suppressed this ligature-induced bone resorbing activity while indomethacin had no effect. Extracts from gingiva from around clean non-ligated teeth had somewhat less activity than extracts from gingiva of ligaled teeth, although some significant resorption remained in all treatment groups. Bacterial cultures from melronidazoletreated groups showed a change from a predominantly Gram negative obligatory anerobic flora (B. assacharolyticus), to one predominated by Gram negative, facultative anaerobes (Capnocytophaga and Campylobacter). It was concluded that metronidazole suppressed bone resorbing activity by inducing a change in the flora of the gingival crevice.
Bone cultures exposed to prostaglandin E2 (PGE2) and revealed an increase in 45Ca release from bone to medium and an increase in osteoclast number compared to control bones. In addition, PGE2-treated osteoclasts contained a more extensive ruffled border region than control osteoclasts. These data suggest that PGE2 activates existing osteoclasts and causes proliferation and differentiation of osteoclast precursor cells. The existence of macrophages in resorbing fetal bone explants was documented. These macrophages contain numerous phagolysosomes and lipid vacuoles and are often located adjacent ot osteoclasts or closely apposed to calcified tissue surfaces. PGE2 caused an early increase in the number of macrophages. It is postulated that fetal bone macrophages are primarily engaged in phagocytosis and digestion of cellular debris, but also play a role in the process of bone resorption.
Histoiogicai aspects of bone remodeling, with special ref-erence to the effects of parathyroid hormone and vitamin D. In: Clinieal Aspects of Me-taboiie Bone Disease Amster-dam: Excerpta Medica
- P Bordier
- S Tunchot
- B W Brown
- Jr
- M Hollander
Bordier, P. & TunChot, S. 1973. Histoiogicai aspects of bone remodeling, with special ref-erence to the effects of parathyroid hormone and vitamin D. In: Clinieal Aspects of Me-taboiie Bone Disease, eds. Erame, B.. Parfitt, A. M. & Duncan, H. pp. 95-102. Amster-dam: Excerpta Medica. Brown, B. W. Jr. & Hollander, M. 1977. Sta-tistics: A Biomedical Introduction, pp. 85-108. New York: John Wiley & Sons.
Histopathological Technique and Practical Histochemisiry
- R D Lillie
- Mcgraw-Hill Book Co