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Handling of cryopreserved amniotic membrane. AmnioGraft ® obtained from Bio-Tissue, Inc., is stored in a foil package in a frozen state. After thawing at room temperature, it can be retrieved aseptically from the inner clear plastic pouch and the membrane is attached to one side of nitrocellulose paper (A and B). Once transferred to the operating field, the membrane can easily be peeled away by two forceps grabbing the two corners while the nurse peels the paper away (C). In general, AmnioGraft is placed with the stromal side on the recipient bed; the side can be discerned by touching it with the tip of a dry MicroSponge™ (Alcon Surgical, TX, USA). The stromal side, but not epithelial side, sticks to the MicroSponge (D).
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Transplantation of cryopreserved amniotic membrane (AM) is a widely accepted surgical procedure to promote epithelial healing and to reduce inflammation, scarring and emerging neovascularization on the ocular surface. Clinical uses of AM for ocular surface reconstruction can be categorized either as a permanent graft or as a biological bandage. Per...
Similar publications
Aim: To evaluate the clinical effect and to determine the correlation between the initial pathology and postoperative outcome in patients with anterior surface dysfunction treated by amniotic membrane transplantation (AMT).
Material and Methods: 174 AMT of cryopreserved amniotic membrane (AM) performed on 128 patients over a period of two years (01...
This study aimed to evaluate the outcomes and described the recovery process of cryopreserved limbal lamellar keratoplasty (CLLK) for peripheral corneal and limbal diseases. Thirteen eyes of 12 patients with a mean age of 41±23.9y were included. The average follow-up was 12.1±5.6mo. Stable ocular surface was achieved in all eyes at last follow-up....
Citations
... AM grafts can be more mobile and lost earlier with suture-free fixation methods, possibly necessitating repeated AMT. 6 Moreover, this can be a disadvantage for PEDs because stable, firm, and long-lasting fixation of AM grafts on the ocular surface seem to facilitate epithelial regeneration in PED patients. To overcome these mentioned drawbacks, we describe a new and easily applicable continuous suturing technique for the stable and firm fixation of AM grafts in PEDs after chemical burns. ...
This case report aims to describe a modified continuous suturing technique for firm fixation of a human amniotic membrane graft in a patient with persistent epithelial defect (PED) after a chemical eye injury. As a result of this technique, the amniotic membrane (AM) was firmly fixed to the corneal surface with eight continuous and locked episcleral sutures that resembled an octagon graft. This technique was performed in a 14-year-old patient with PED after a chemical corneal burn. Three weeks after the surgery, the PED was completely healed. This simple continuous suturing technique can allow firm and stable fixation of AM grafts on the ocular surface in cases of PED after chemical burn. It may prevent early loss of the graft and facilitate corneal epithelial wound healing.
... In recent years, many carriers have been used to culture LECs; however, the majority of previous studies have used HAM as a choice of carrier due to its low-cost procurement, easy availability, and ability to maintain stemness of the culture, promote epithelialization, and reduce inflammation and scarring [11][12][13][28][29][30][31][32][33]. Nonetheless, due to its biologic origin, HAM carries inherent risks such as disease transmission and infection that cannot be totally avoided [14,15]. ...
The aim of this study was to develop a synthetic stromal substrate for limbal epithelial cell (LEC) expansion that can serve as a potential alternative substrate to replace human amniotic membrane (HAM).
Nanofibers were fabricated using 10% poly-ε-caprolactone (PCL) solution dissolved in trifluoroethanol (TFE) via an electrospinning process. Nanofibers were characterized for surface morphology, wetting ability, pore size, mechanical strength, and optical transparency using scanning electron microscopy (SEM), contact angle measurement, microtensile tester, and UV-Vis spectrophotometer, respectively. The human corneal epithelial (HCE-T) cell line was used to evaluate the biocompatibility of nanofibers based on their phenotypic profile, viability, proliferation, and attachment ability. Subsequently, human LECs were cultivated on biocompatible nanofibers for two weeks and their proliferation capability analyzed using MTT ((3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, a yellow tetrazole)) proliferation assay. Immunofluorescent (IF) staining and reverse transcriptase polymerase chain reaction (RT-PCR) were performed to check the molecular marker expression; SEM was used to study the morphology.
The average fiber diameter of PCL was 132±42 nm. Pore size varied from 0.2 to 4 microns with a porosity of 85%. The tensile strength of the PCL membrane was 1.74±0.18 MPa (Mega Pascal); strain was 30.08±2.66%. The water contact angle was 90°. Biocompatibility results indicated that the polymer surface was highly biocompatible, as HCE-T cells could favorably attach and proliferate on the polymer surface. SEM figures showed that the corneal epithelium was firmly anchored to the polymer surface via a continuous cell sheet and was able to retain a normal corneal phenotype. MTT assay confirmed that cells were metabolically active on nanofibers (p<0.05) and gradually increased in their number for up to two weeks. IF and RT-PCR results revealed no change in the expression profile of LECs grown on nanofibers when compared to those grown on glass coverslips and human amniotic membrane (HAM). Confocal microscopy illustrated that cells infiltrated the nanofibers and successfully formed a three-dimensional (3D) corneal epithelium, which was viable for two weeks.
Electrospun nanofibers provide not only a milieu supporting LEC expansion, but also serve as a useful alternative carrier for ocular surface tissue engineering and could be used as an alternative substrate to HAM.
... The fibrin bioadhesive biodegrades within 2 weeks, whereas the amniotic membrane persists for at least 12 weeks, providing sufficient time for epithelialization (Sekiyama et al., 2007). Sutureless transplantation with fibrin glue or ProKera™ is reportedly a safe and easy method that avoids complications related to sutures and shortens the time of surgery (Kheirkhah et al., 2006). ...
... Growth of polarized lacrimal acinar cells on PLLA, which demonstrated the ability to maintain normal monolayer acinar cell morphology, secretory function, and EGF-dependent proliferation, suggests that PLLA may be a good candidate for the development of a tear secretory device. A dead-end tube construct using polyethersulfone has been reported (Li et al., 2006;). After seeding the tube with cultured rat lacrimal acinar epithelial cells, the authors observed that a polyethersulfone dead-end tube may be suitable for attachment and proliferation of these cells, allowing its potential application as an artificial lacrimal gland. ...
Human amniotic membrane has been widely used in ophthalmology for decades, particularly in ocular surface reconstruction. This article reviews its mechanism of action, surgical principles and clinical applications. The fate of transplanted amniotic membrane in the eye and its limitations will also be addressed.
Intricate homeostasis maintains the rich complexity and functionality of the ocular surface. Severe ocular surface diseases cause significant morbidities, including blindness. Ocular surface reconstruction strategies restore this homeostasis. Patients with limbal deficiency may benefit from limbal stem cell transplantation to alleviate persistent epithelial defects, maintain conjunctivalization regression and corneal avascularity, and restore vision. Amniotic membrane and other substrates function as tissue surrogates and substrates for expansion of stem cells. Maximum graft survivability necessitates aggressive and comprehensive preoperative management of inflammation, infection, microtrauma, dry eye conditions and HLA compatibility. Restoration of lacrimal gland function is important, as is implementation of aggressive immunosuppression. Future advancements in stem cell biology, tissue engineering, bioartificial microsystems or regenerative medicine will supplement the therapeutic armamentarium. The next decade will be an exciting time for corneal surgeons.
To evaluate the efficacy of amniotic membrane transplantation (AMT) to improve the outcomes of acute Pseudomonas keratitis as compared with a control group.
Prospective interventional case series with retrospective controls.
We studied 14 eyes with Pseudomonas keratitis as the AMT group and 11 eyes with Pseudomonas keratitis as the control group.
Eyes in the AMT group were treated with antibiotic therapy followed by single-layer AMT at 2 to 3 days. Eyes in the control group received only antibiotic therapy. Patients were followed for 11.1 ± 2.4 months.
In the AMT group, pain significantly decreased from a mean score of 2.4 ± 0.5 preoperatively to 1.1 ± 0.9 at day 2 postoperatively (p < 0.001). Corneal epithelial defects healed completely within 13.2 ± 2.6 days in the AMT group compared with 15.5 ± 3.4 days in the control group (p = 0.07). At final follow-up visits, the sizes of corneal opacity and deep neovascularization were not different between the 2 groups. However, the mean score for density of the corneal opacity was significantly less in the AMT group compared with the control group (2.1 ± 0.4 vs 2.5 ± 0.7, respectively, p = 0.04). Although the best corrected visual acuity using hard contact lenses was not different between the 2 groups, uncorrected visual acuity was better in the AMT group (0.45 ± 0.22 logMAR) than in the control group (0.71 ± 0.32 logMAR, p = 0.03). No patient in either group developed significant corneal thinning or perforation.
AMT in acute Pseudomonas keratitis was associated with immediate pain relief, less density of the final corneal opacity, and better uncorrected visual acuity at the final follow-up visit.
