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Effect of normovolemic hemodilution on blood pH-value (A), pO 2 (B), pCO 2 (C), glucose (D) and lactate (E). During hemodilution (grey background), animals were diluted using 5% HSA (control) or 12 vol% capsules (treatment) to a hematocrit of 5%. The plots show the mean ± SEM of n = 8 animals per group. Asterisk indicates significance with p < 0.05 compared to the controls.
Source publication
Artificial blood for clinical use is not yet available therefore, we previously developed artificial oxygen carriers (capsules) and showed their functionality in vitro and biocompatibility in vivo. Herein, we assessed the functionality of the capsules in vivo in a normovolemic hemodilution rat-model. We stepwise exchanged the blood of male Wistar-r...
Contexts in source publication
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... base status and metabolic parameters. The data on acid base status and metabolic parameters revealed significant differences during the hemodilution period (Fig. ...
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... blood pH of the animals in both groups remained stable at a similar level from the beginning of the experiment until the end of the dilution period ( Fig. 2A). Within this experimental period, the pH of the control animals varied between pH 7.23 and pH 7.28 and the pH of the capsule-treated animals between pH 7.21 to pH 7.30. Post-dilution pH in the animals of the control group, dropped to a final acidotic value of pH 7.14 ± 0.1 (minute 230) while the pH value of the treatment group remained ...
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... the whole experiment, the arterial pO 2 of the animals in the control group was below the pO 2 level of the capsule-treated animals. At several time points the difference reached significant levels (Fig. 2B). Immediately after the start of the dilution a clear difference of 81 mmHg between the two groups was noticed (minute 18: control: 396.1 ± 31 mmHg, treatment: 477.6 ± 15 mmHg). This difference increased throughout the dilution period and reached significance in minute 126, 144 and 162. At minute 162, the maximum difference between the ...
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... arterial pCO 2 from animals of the control group was consistently higher than the pCO 2 of treatment group (Fig. 2C). In addition, a difference of 10 mmHg between both groups was noticed immediately after the start of the dilution (minute 18) (control: 61.8 ± 3 mmHg, treatment: 51.6 ± 3 mmHg). This difference remained until the end of the dilution period with significantly different values at minute 90. At the end of the post-dilution period (minute ...
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... glucose concentration (Fig. 2D) were similar for both groups at the beginning of the experiment (control: 176.1 ± 10 mg/dl, treatment: 165.6 ± 10 mg/dl). In animals of both groups, blood glucose concentration moderately increased until minute 108 (control: 213.2 ± 12 mg/dl, treatment: 203.1 ± 11 mg/dl). Subsequently, blood glucose concentration of the control animals ...
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... lactate concentration of the animals (Fig. 2E) was around 2 mmol/l in both groups until minute 160, significant differences occurred between the two groups in minute 90, 108 and 126. From minute 180, the blood lactate values of the control animals strongly increased to 6.8 ± 1.5 mmol/l in minute 230. In comparison, blood lactate levels of capsule-treated animals only marginally ...
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... line with Gellhorn's results the animals of the control group showed a lower pO 2 (Fig. 2B) and a higher pCO 2 (Fig. 2C), compared to the animals of the treatment group. Presumable, the loss of body core temperature, as characterized by Gellhorn et al., is attributable to the deficient oxygen supply and the simultaneous increase of pCO 2 in the control animals. In contrast, the treatment animals showed a higher pO 2 and ...
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... line with Gellhorn's results the animals of the control group showed a lower pO 2 (Fig. 2B) and a higher pCO 2 (Fig. 2C), compared to the animals of the treatment group. Presumable, the loss of body core temperature, as characterized by Gellhorn et al., is attributable to the deficient oxygen supply and the simultaneous increase of pCO 2 in the control animals. In contrast, the treatment animals showed a higher pO 2 and lower pCO 2 and could thereby ...
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... by Gellhorn et al., is attributable to the deficient oxygen supply and the simultaneous increase of pCO 2 in the control animals. In contrast, the treatment animals showed a higher pO 2 and lower pCO 2 and could thereby maintain their body core temperature. During hemodilution the animals of the treatment group sustained a stable pH ( Fig. 2A), which allows to conclude a positive influence on the acid base status by the capsules. Nevertheless, animals of the treatment group showed a decrease in plasma glucose concentration although the solution used for hemodilution contained physiological plasma glucose concentrations (10 mM) of the rat (Fig. 2D). To exclude a hormonal ...
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... treatment group sustained a stable pH ( Fig. 2A), which allows to conclude a positive influence on the acid base status by the capsules. Nevertheless, animals of the treatment group showed a decrease in plasma glucose concentration although the solution used for hemodilution contained physiological plasma glucose concentrations (10 mM) of the rat (Fig. 2D). To exclude a hormonal influence on blood glucose-level due to dysregulated pancreatic function, we analysed pancreatic hormones (Fig. 7). The animals of the control group showed an increase in both hormones, which indicates a dysregulation of the pancreas in the control group and not as expected in the capsule group. This loss of ...
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... to stabilize their metabolism via both glycogenolysis and gluconeogenesis. In contrast, control animals seemed to be insufficient to mobilize their metabolic reserves for surviving, which might be due to a hypoxic status and could be the reason for dying. In any case, in the control animals the progression of plasma glucose level is more clear (Fig. 2D). During the hemodilution period, when more and more organs reach their critical hematocrit, animals showed a typical stress reaction (increase in plasma glucose). With progressive oxygen shortage (during the post-hemodilution phase), remaining glucose was used for anaerobic glycolysis, reflected in increasing lactate levels (Fig. 2E). ...
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... more clear (Fig. 2D). During the hemodilution period, when more and more organs reach their critical hematocrit, animals showed a typical stress reaction (increase in plasma glucose). With progressive oxygen shortage (during the post-hemodilution phase), remaining glucose was used for anaerobic glycolysis, reflected in increasing lactate levels (Fig. 2E). The fact that plasma lactate did not increase in capsule-diluted animals supports the hypothesis of sufficient oxygenation of those ...
Citations
... Furthermore, in a hypoxic-hypoxia situation, elevated blood glucose levels were previously shown to be an adaptive response to stress (Wrobeln et al., 2020). Despite this, we found that hypoxic-stressed control animals and the hypoxic-stressed hypothyroid animals had higher fasting blood glucose levels, which we attributed to stress. ...
A double‐hit biological alteration involving exposure to oxygen deprivation in hypothyroid condition may exacerbate cellular oxidative and inflammatory disturbances comparative to a one‐hit biological exposure. This study investigated the therapeutic effect of Ginkgo biloba as cardioprotective against aortic oxido‐inflammatory disturbances following oxygen deprivation in hypothyroid mice. Male Swiss mice were partitioned into 5 groups (n = 6) for hypothyroidism (Carbimazole 1.2 mg/kg) and hypoxia induction. Group 1 (normal control), group 2 (hypoxic stress control), group 3 (hypoxic and hypothyroid stress), group 4 (hypoxic and hypothyroid stress and Ginkgo biloba 20 mg/kg; p.o) and group 5 (hypoxic and hypothyroid stress and Levothyroxine 10 μg/kg; p.o) for 14 days. Thereafter, serum and aorta was collected for biochemical evaluation. GBS did not up‐regulate the serum thyroid hormone imbalances (tri‐iodothyronine (T3), thyroxin (T4)) but maintains the TSH levels. The blood glucose level was reduced with decrease oxidative stress and inflammatory mediators in the serum/aorta indicated by inhibited redox status following treatment with GBS. Moreover, endothelin‐1/nitric oxide signaling pathways were markedly regulated in the aorta. Conclusively, GBS acts as a therapeutic agent and may be consider as a potential vasodilator candidate in the management and control of hypoxic stress in hypothyroid condition.
Practical applications
Treatment with Gingko biloba supplement abated endothelial abnormalities via elevation of nitric oxide release and suppression of endothelin activity in hypothyroid mice exposed to hypoxic hypoxia.
The activity of myeloperoxidase enzyme and redo‐inflammatory status was downregulated following treatment with Gingko biloba supplement in hypothyroid mice exposed to hypoxic hypoxia.
Treatment with Gingko biloba supplement modulates hypothalamic–pituitary–adrenal (HPA) axis by inhibiting corticosterone release in hypothyroid mice exposed to hypoxic hypoxia.
... The most commonly used PFCs for oxygen carrier emulsions are perfluorodecalin (0.403 mL O2 /mL PFC ), perfluorooctylbromid (0.527 mL O2 /mL PFC ), and dodecafluoropentane (0.029 mL O2 / mL PFC ). 2 This study investigated a perfluorodecalin-based emulsion, which proved to be highly potent in concentrations of 4−6% to maintain the oxygen supply in a model of ex vivo perfusion of a rat kidney and in a severe hemodilution model of the rat. 7,21 To test the maximal capability to transfer the oxygen, this DOT was determined using human blood of three volunteers in which preoxygenated emulsion with a volume fraction of 17% was injected in gas-tight syringes. The theoretical amount of O 2 in 50 μL of the emulsion is 3.34 μL. ...
This work aimed at the development of a stable albumin-perfluorocarbon (o/w) emulsion as an artificial oxygen carrier suitable for clinical application. So far, albumin-perfluorocarbon-(o/w) emulsions have been successfully applied in preclinical trials. Cross-linking a variety of different physical and chemical methods for the characterization of an albumin-perfluorocarbon (PFC)-(o/w) emulsion was necessary to gain a deep understanding of its specific emulsification processes during high-pressure homogenization. High-pressure homogenization is simple but incorporates complex physical reactions, with many factors influencing the formation of PFC droplets and their coating. This work describes and interprets the impact of albumin concentration, homogenization pressure, and repeated microfluidizer passages on PFC-droplet formation; its influence on storage stability; and the overcoming of obstacles in preparing stable nanoemulsions. The applied methods comprise dynamic light scattering, static light scattering, cryo- and non-cryo-scanning and transmission electron microscopies, nuclear magnetic resonance spectroscopy, light microscopy, amperometric oxygen measurements, and biochemical methods. The use of this wide range of methods provided a sufficiently comprehensive picture of this polydisperse emulsion. Optimization of PFC-droplet formation by means of temperature and pressure gradients results in an emulsion with improved storage stability (tested up to 5 months) that possibly qualifies for clinical applications. Adaptations in the manufacturing process strikingly changed the physical properties of the emulsion but did not affect its oxygen capacity.
... In addition, A-AOC displayed stable body temperature, pH, higher partial pressure of oxygen, and lower partial pressure of CO 2 , which was better for improved oxygenation. It can Lambert and Janjic (2021) impede hypoxic tissue damage, although it shows higher arterial blood pressure and lower blood glucose levels in treated rats (Wrobeln et al. 2020). Moreover, it significantly decreased decompression sickness (DCS) lesions and mortality rates in a rat model (Mayer et al. 2020). ...
... Newly developed albumin-derived PFC-based nanoparticles act as novel AOCs and exhibit higher oxygen transportation capacity without many undesirable effects in rat animal models (Wrobeln et al. 2017a). In addition, these nanoparticles can also protect tissues from hypoxic damage; however, they have not yet been tested in clinical trials (Wrobeln et al. 2020). The study of PFOCs was successful in non-cardiac surgery without major safety concerns, and reduced the need for allogeneic RBC transfusion (Spahn 2018). ...
Background:
Several circumstances such as accidents, surgery, traumatic hemorrhagic shock, and other causalities cause major blood loss. Allogenic blood transfusion can be resuscitative for such conditions; however, it has numerous ambivalent effects, including supply shortage, needs for more time, cost for blood grouping, the possibility of spreading an infection, and short shelf-life. Hypoxia or ischemia causes heart failure, neurological problems, and organ damage in many patients. To address this emergent medical need for resuscitation and to treat hypoxic conditions as well as to enhance oxygen transportation, researchers aspire to achieve a robust technology aimed to develop safe and feasible red blood cell substitutes for effective oxygen transport.
Area covered:
This review article provides an overview of the formulation, storage, shelf-life, clinical application, side effects, and current perspectives of artificial oxygen carriers (AOCs) as red blood cell substitutes. Moreover, the pre-clinical (in vitro and in vivo) assessments for the evaluation of the efficacy and safety of oxygen transport through AOCs are key considerations in this study. With the most significant technologies, hemoglobin- and perfluorocarbon-based oxygen carriers as well as other modern technologies, such as synthetically produced porphyrin-based AOCs and oxygen-carrying micro/nanobubbles, have also been elucidated.
Expert opinion:
Both hemoglobin- and perfluorocarbon-based oxygen carriers are significant, despite having the latter acting as safeguards; they are cost-effective, facile formulations which penetrate small blood vessels and remove arterial blockages due to their nano-size. They also show better biocompatibility and longer half-life circulation than other similar technologies.
... The biocompatibility and safe application of non-lyophilized perfluorodecalin-filled albumin-based nanocapsules has already been successfully demonstrated in in vivo studies [13,15]. Corresponding properties are also essential for the freeze-dried nanocapsules. ...
... Perfluorodecalin-filled albumin-based nanocapsules are promising artificial oxygen carriers and their biocompatibility and functionality have already been demonstrated [14,15]. However, in the present study, the nanocapsules proved to be unstable while stored in form of an aqueous suspension. ...
Every day, thousands of patients receive erythrocyte concentrates (ECs). They are indispensable for modern medicine, despite their limited resource. Artificial oxygen carriers (AOCs) represent a promising approach to reduce the need for ECs. One form of AOCs is perfluorodecalin-filled albumin-based nanocapsules. However, these AOCs are not storable and need to be applied directly after production. In this condition, they are not suitable as a medicinal product for practical use yet. Lyophilization (freeze drying) could provide the possibility of durable and applicable nanocapsules. In the present study, a suitable lyophilization process for perfluorodecalin-filled nanocapsules was developed. The nanocapsules were physicochemically characterized regarding capsule size, polydispersity, and oxygen capacity. Even though the perfluorodecalin-filled albumin-based nanocapsules showed a loss in oxygen capacity directly after lyophilization, they still provided a remarkable residual capacity. This capacity did not decline further for over two months of storage. Furthermore, the nanocapsule size remained unaltered for over one year. Therefore, the AOCs were still applicable and functional after long-term storage due to the successful lyophilization.
... Furthermore, PFOCs stay rather close to the endothelia and shorten the diffusion distance between RBCs and the endothelium whilst acting as stepping-stones for O 2 (Fig. 3C) [20,37,78]. This facilitated diffusion is helpful in cases of blood loss caused by extensive bleeding or haemodilution, e. g. during operations assisted by heartlung machines [103]. ...
Developing biocompatible, synthetic oxygen carriers is a consistently challenging task that researchers have been pursuing for decades. Perfluorocarbons (PFC) are fascinating compounds with a huge capacity to dissolve gases, where the respiratory gases are of special interest for current investigations. Although largely chemically and biologically inert, pure PFCs are not suitable for injection into the vascular system. Extensive research created stable PFC nano-emulsions that avoid (i) fast clearance from the blood and (ii) long organ retention time, which leads to undesired transient side effects. PFC-based oxygen carriers (PFOCs) show a variety of application fields, which are worthwhile to investigate. To understand the difficulties that challenge researchers in creating formulations for clinical applications, this review provides the physical background of PFCs’ properties and then illuminates the reasons for instabilities of PFC emulsions. By linking the unique properties of PFCs and PFOCs to physiology, it elaborates on the response, processing and dysregulation, which the body experiences through intravascular PFOCs. Thereby the reader will receive a scientific and easily comprehensible overview why PFOCs are precious tools for so many diverse application areas from cancer therapeutics to blood substitutes up to organ preservation and diving disease.
Sonodynamic therapy (SDT) has emerged as a highly effective modality for the treatment of malignant tumors owing to its powerful penetration ability, noninvasiveness, site‐confined irradiation, and excellent therapeutic efficacy. However, the traditional SDT, which relies on oxygen availability, often fails to generate a satisfactory level of reactive oxygen species because of the widespread issue of hypoxia in the tumor microenvironment of solid tumors. To address this challenge, various approaches are developed to alleviate hypoxia and improve the efficiency of SDT. These strategies aim to either increase oxygen supply or prevent hypoxia exacerbation, thereby enhancing the effectiveness of SDT. In view of this, the current review provides an overview of these strategies and their underlying principles, focusing on the circulation of oxygen from consumption to external supply. The detailed research examples conducted using these strategies in combination with SDT are also discussed. Additionally, this review highlights the future prospects and challenges of the hypoxia‐alleviated SDT, along with the key considerations for future clinical applications. These considerations include the development of efficient oxygen delivery systems, the accurate methods for hypoxia detection, and the exploration of combination therapies to optimize SDT outcomes.
Ischemia or hypoxia can lead to pathological changes in the metabolism and function of tissues and then lead to various diseases. Timely and effective blood resuscitation or improvement of hypoxia is very important for the treatment of diseases. However, there is a need to develop stable, nontoxic, and immunologically inert oxygen carriers due to limitations such as blood shortages, different blood types, and the risk of transmitting infections. With the development of various technologies, oxygen carriers based on hemoglobin and perfluorocarbon have been widely studied in recent years. This paper reviews the development and application of hemoglobin and perfluorocarbon oxygen carriers. The design of oxygen carriers was analyzed, and their application as blood substitutes or oxygen carriers in various hypoxic diseases was discussed. Finally, the characteristics and future research of ideal oxygen carriers were prospected to provide reference for follow-up research.
The issues of practicality in using perfluorocarbon gas transport emulsions (or pure perfluorocarbons) in severe virus-associated pneumonia treatment were considered, including those caused by coronavirus infection. Perfluorocarbons are fully fluorinated carbon compounds, on the basis of which artificial blood substitutes have been developed gas transport perfluorocarbon emulsions for medical purposes. Perfluorocarbon emulsions were widely used in the treatment of patients in critical conditions of various genesis at the end of the lastthe beginning of this century, accompanied by hypoxia, disorders of rheological properties and microcirculation of blood, perfusion of organs and tissues, intoxication, and inflammation. Large-scale clinical trials have shown a domestic plasma substitute advantage based on perfluorocarbons (perfluoroan) over foreign analogues. It is quite obvious that the inclusion of perfluorocarbon emulsions in the treatment regimens of severe virus-associated pneumonia can significantly improve this categorys treatment results after analyzing the accumulated experience. A potentially useful area of therapy for acute respiratory distress syndrome is partial fluid ventilation with the use of perfluorocarbons as respiratory fluids as shown in the result of many studies on animal models and existing clinical experience. There is no gas-liquid boundary in the alveoli, as a result of which, there is an improvement in gas exchange in the lungs and a decrease in pressure in the respiratory tract when using this technique, due to the unique physicochemical properties of liquid perfluorocarbons. A promising strategy for improving liquid ventilation effectiveness using perfluorocarbon compounds is a combination with other therapeutic methods, particularly with moderate hypothermia. Antibiotics, anesthetics, vasoactive substances, or exogenous surfactant can be delivered to the lungs during liquid ventilation with perfluorocarbons, including to the affected areas, which will enhance the drugs accumulation in the lung tissues and minimize their systemic effects. However, the indications and the optimal technique for conducting liquid ventilation of the lungs in patients with acute respiratory distress syndrome have not been determined currently. Further research is needed to clarify the indications, select devices, and determine the optimal dosage regimens for perfluorocarbons, as well as search for new technical solutions for this technique.
Artificial oxygen ca obtain a stable mixture. Perfluorocarbons rriers are classified into two broad categories: hemoglobin-based and perfluorocarbon-based. Both provide oxygen transport to tissues. For several decades, perfluorocarbons have been explored as oxygen carriers in a variety of biological applications. Perfluorocarbons are chemically and physiologically inert, have excellent temperature and storage stability, represent little to no infectious danger, are commercially available, and have well-established gas transport qualities. Perfluorocarbons are compounds that have high solubility for many gases, but they are not suitable for direct injection into the vascular system and require emulsification to obtain a stable mixture. Perfluorocarbons may be classified into five categories based on the primary perfluorocarbon backbone utilized in the product: (1) perfluorodecalin, (2) perfluorooctyll bromide, (3) tertbutylperfluorocyclohexane, (4) dodecafluoropentane, and (5) perftoran. When combined with other blood-saving strategies, the use of perfluorocarbon-based oxygen carriers enables the performance of surgical procedures with increased blood loss while eliminating or lowering the need for allogeneic transfusion. Other applications have been described and are under investigation.
