Amniotic Membrane Patch Research Articles

Focal lesion keratectomy combined with cryotherapy and biological amnion covering in the management of fungal corneal ulcer

Objective To examine the efficacy of focal lesion keratectomy combined with cryotherapy and biological amnion covering in the management of fungal corneal ulcer. Methods Seventeen patients (17 eyes) with fungal corneal ulcer were treated with focal lesion keratectomy combined with cryotherapy and biological amnion covering between January 2009 and October 2009. The course of diseases was 20 days to 3 months (36.1±16.3 days), There was a a 5 mm corneal ulcer in the 14 cases. 9 cases(9 eyes)of 17 patients had hypopyon. We investigated the healing of corneal ulcer and covering of amniotic membrane with slit lamp microscope, complications and ulcer recurrences were analysed. Results All the cases were followed up for 3 to 12 months after operation of them, Fungal infection were controlled and corneal ulcer healed within 3-4 weeks postoperatively in 11 patients, 6 cases were carried out penetrative keratoplasty because of the uncontrolled keratomycosis. Superficial amniotic membrane patches dissolved or shed on postoperative 7-10 days. No complication occurred. Conclusion Focal lesion keratectomy combined with cryotherapy and amniotic membrane covering is an effective method in the a part of patients with fungal corneal ulcer . Key words: corneal ulcer,fungal; local lesion resection; cryotherapy; amniotic membrane

Use of Amniotic Membrane Graft in Glaucoma Shunt Surgery

To determine the safety and efficacy of amniotic membrane graft in glaucoma drainage device surgery. Institutional retrospective case series of 44 patients undergoing glaucoma drainage device implantation with use of 300-μm thick amniotic membrane as a patch graft. Endpoints assessed were tube exposure, graft thinning, graft clarity, graft-related infection, and inflammation. A total of 41 (93%) eyes had an uneventful course over a mean follow-up of 22 ± 3 months (range: 17 to 28 months). Tube exposure and hypotony each occurred in one eye and were successfully treated with a tube revision using double pericardial and amniotic membrane patch graft. The translucency of amniotic membrane graft enabled good visualization of the occluding suture when performing laser suture lysis in 16 eyes. Sequential anterior segment optical coherence tomography showed stable amniotic membrane graft thickness with a change from low to moderate reflectivity in the subconjunctival-graft bilayer. Amniotic membrane graft offers good tectonic support and allows direct visualization of the underlying tube.

Amniotic Membrane Application Reduces Liver Fibrosis in a Bile Duct Ligation Rat Model

Biliary fibrosis and resultant cirrhosis are among the most common outcomes of chronic liver diseases. Currently, liver transplantation remains the only effective treatment. In seeking alternative therapeutic approaches, we focused on the potential use of the human amniotic membrane (AM). Indeed, AM has gained increasing importance for its antiscarring, anti-inflammatory, and wound-healing properties, as well as for the multipotent differentiation ability and immunomodulatory features of AM-derived cells. Intriguingly, we have recently demonstrated that placenta-derived cells reduce lung fibrosis in bleomycin-treated mice, and that AM patches reduce postischemic cardiac injury in rats. Hence, we have now investigated the effects of human AM on biliary fibrosis induced in rats through the bile duct ligation (BDL) procedure. A fragment of human AM was applied onto the liver surface after BDL and the effects on fibrosis establishment and progression were evaluated at different time points in comparison with fibrosis progression in control BDL rats. The degree of liver fibrosis was first assessed by the semiquantitative Knodell scoring system and, thereafter, by digital image morphometric analysis to quantify the area occupied by ductular reaction, activated myofibroblasts, and collagen deposition. We demonstrated a significant reduction in the severity of BDL-induced fibrosis in AM-treated rats. Indeed, while fibrosis progressed rapidly in control BDL rats, leading to cirrhosis within 6 weeks, AM-treated rats showed confined fibrosis at the portal/periportal area with no signs of cirrhosis, and a reduction in collagen deposition to about 50% of levels observed in control BDL rats. In addition, the AM was able to significantly slow the gradual progression of the ductular reaction and reduce, at all time points, the area occupied by activated myofibroblasts. These findings suggest that human AM, when applied as a patch onto the liver surface, might inhibit fibrosis progression in BDL-injured livers, and could protect against hepatic damage associated with fibrotic degeneration.

Simultaneous Amniotic Membrane Patch in High-risk Keratoplasty

To analyze the short- and intermediate-term results of simultaneous transplantation of amniotic membrane with high-risk keratoplasty. Between January 2002 and February 2004, a simultaneous amniotic membrane patch was transplanted with penetrating keratoplasty in 16 eyes of 16 patients. In 13 eyes, a soft contact lens was applied afterward. Corneal perforation was present in 10 of 14 eyes with emergency keratoplasty. Five patients received systemic immunosuppressive medication for 4-6 months after penetrating keratoplasty. The amniotic membrane patch fell off after 8 ± 3 (range: 4-14) days without residual tissue except in 1 case. In 15 of 16 eyes, the epithelium was completely closed after 10 ± 8 (range: 4-30) days. In 3 eyes, recurrence of the epithelial defect occurred after 3-6 months. During a follow-up period of 18 ± 6 months, 13 of 16 corneal grafts were clear. Simultaneous amniotic membrane transplantation and penetrating keratoplasty may improve the prognosis of corneal graft in eyes with risk of epithelial healing problems.

In Vivo Analysis of Stromal Integration of Multilayer Amniotic Membrane Transplantation in Corneal Ulcers

To evaluate integration of amniotic membrane into the corneal stroma using laser scanning in vivo confocal microscopy and anterior segment optical coherence tomography (AS-OCT). Prospective noncomparative interventional case series. Twenty-two eyes of 22 consecutive patients (mean age 53.9 ± 9.2 years) presenting with noninfectious corneal ulcers and stromal thinning unresponsive to medical treatment were enrolled. Multiple layers of amniotic membrane were applied over the ulcer bed to fill the ulcer crater and held in place with an overlying amniotic membrane patch, which was anchored to the surrounding cornea with 10-0 nylon interrupted sutures. Outcome measures were healing of the corneal ulcers, corneal morphology and stromal thickness changes at the ulcer site as measured by AS-OCT and surface epithelialization, stromal repopulation, and structural modifications of the amniotic membrane grafts as evaluated by confocal microscopy. Follow-up extended to 12 months. Successful result was observed in 20 of 22 eyes (90.9%). AS-OCT showed that the mean residual stromal thickness at the ulcer bed was 222 ± 70 μm before surgery. The mean thickness of amniotic membrane layers at the same site was 394 ± 80 μm while the mean total corneal thickness was 623 ± 51 μm at day 1 post surgery. Thereafter a progressive reduction in thickness to 420 ± 61 μm at 6 months occurred, after which the thickness stabilized. Confocal microscopy showed that integration of the amniotic membrane tissues with corneal stroma was preceded by epithelialization over the amniotic membrane covering the ulcer. This occurred 15 ± 5 days post surgery in the successful cases. Confocal microscopy also showed that the amniotic membrane patch was degraded during the first few weeks after surgery, while the integrated amniotic tissues underwent progressive modifications characterized by early loss of amniotic epithelial cells, changes in fibrillar structure, and migration into the amniotic stroma by corneal stroma-derived cells. Multiple layers of amniotic membrane can integrate into the corneal stroma with resulting increase in corneal thickness. This appears to be related to re-epithelialization of the transplanted membrane. Integrated amnion within the stromal defect undergoes progressive changes including contraction of tissue and repopulation by corneal stroma-derived cells.

Development and Evaluation of a Device for Sutureless and Repeated Application of Amniotic Membrane Overlays

To develop a prototype device for sutureless and repeated ocular surface treatments with overlay amniotic membranes and to describe the main results of various prototype modifications. In this experimental, descriptive study, various modifications of a ring-like device were designed and manufactured. The different variants were tested for comfort, local stability, and corneal contact. The final prototype was photographed during different ocular deviations and investigated at a slit lamp for the fit of the device within the fornices and the integrity of the membrane on the ocular surface. Ultrasound was performed with the final prototype to document the distance between the corneal surface and the amniotic membrane that was sutured to the device. The main outcome measures were feasibility of the device setting into the regular fornices, corneal contact of the device during different ocular deviations, comfort, and local stability during 7 days of continuous wearing. One prototype with five modifications was manufactured and tested. An amniotic membrane patch was sutured onto the final prototype and laid into the fornices of a human eyeball during 7 days of continuous wearing. On slit-lamp examination, the amniotic membrane always appeared attached to the complete human cornea and limbal region without macroscopically visible wrinkling. No side effects were observed. The final ellipsoid device enables sutureless and repeated treatment with amniotic membrane overlays and was comfortable in one patient during 7 days of continuous wearing. Limitations of the device such as in cicatriceal foreshortening and possible therapeutic effects need to be determined in future studies.

The use of amniotic membrane in the repair of duodenal wounds in Wistar rats

In the search of a new material to repair duodenal wounds, a trial was conducted to assess the behavior of human amniotic membrane in the repair of the duodenal wall in rats. Fifty Wistar rats weighing between 250 and 350g, male, were submitted to duodenotomy and randomly distributed into two groups. Group A (n=8) had no treatment and was used as the control group. In Group B (n=42) the duodenal wound was treated with a patch of human amniotic membrane. All animals in Group A died. In Group B no changes were observed with regards to death or the formation of duodenal fistula. All animals presented peritoneal adherences in the region on the duodenal wall repair and intestinal obstruction was observed in two animals. Healing of the duodenal wall in the region of the patch took place progressively as the post-operatory period increased, with regeneration of the mucosa and of the smooth muscle layer. From the clinical standpoint, the amniotic membrane proved to be a biological tissue which served as a temporary seal and allowed the wound to heal by second-intention, with re-establishment of the duodenal wall structure.

The change of cytokines in tear and blood after different pterygium operation

Pterygium is an invasion of altered ocular tissue into the cornea. Bone marrow-derived stem cells have been reported to be involved in wound healing under chemotactic factors after pterygium removal and pain may act as a trigger signal. We evaluated the change of systemic and local chemotactic factors that could affect the mobilization and migration of BMSCs to the wound bed after conventional bare sclera pterygium excision. We also applied temporary amniotic membrane patch after pterygium removal, and compared the changes of cytokines with those of conventional bare sclera excision group. Substance-P (SP), vascular endothelial growth factor (VEGF), and stem cell factor (SCF) were measured in plasma and tear using ELISA and migrating CD34 + cells by flow cytometry. The results showed that post-operative pain was much reduced ( p < 0.05), and SP, VEGF and SCF kept consistently lower levels in plasma after temporary amniotic membrane application. Circulating CD34 + cells increased slightly in the temporary amniotic membrane patch group compared with marked increase in the bare sclera group. Thus, the application of a temporary amniotic membrane after pterygium removal might be an effective therapeutic means by controlling pain and excessive infiltration of bone marrow-derived stem cells.

Effects of sutureless amniotic membrane patching with 2-Octyl cyanoacrylate (Dermabond) on experimental corneal alkali burn in dogs

This study was performed to evaluate the surgical technique required and the clinical usefulness of tissue adhesive (2-Octyl cyanoacrylate) combined with amniotic membrane (AM) patching in the treatment of experimental corneal burn in dogs. Alkali wounds were inflicted on the central corneas of dogs by applying a round filter paper, 6.0 mm in diameter, soaked in 1 M NaOH for 60 s. Only one eye in each dog was used. A total of 15 dogs were divided into three groups of five animals each: (1) uncovered—control, (2) covered by AM with the amnion cell side down and secured with 10–0 nylon sutures to the cornea around the wound area—AM + suture, and (3) covered by sutureless AM patching secured with 2-Octyl cyanoacrylate (Dermabond)—AM + glue. The operating time was compared between both treatment groups. Clinical outcome was monitored by evaluation of epithelial defects, corneal opacity, duration of blepharospasm, time of AM persistence, corneal vascularisation, and duration of ocular discharge. The mean surgery time in AM + suture group was significantly longer than AM + glue group. AM persistence in AM + glue group was significantly greater than AM + suture group. The duration of ocular discharge and corneal vascularisation in AM + glue group was significantly lower in comparison with control group. Epithelial healing was faster in the AM + glue group than in controls. In conclusion, sutureless AM patching with 2-Octyl cyanoacrylate (Dermabond) as a dressing on a corneal alkali burn, used for the first time in this research, may induce rapid epithelial healing with less vascularisation and be a much faster and useful technique in dogs.

A Hyperdry Amniotic Membrane Patch Using a Tissue Adhesive for Corneal Perforations and Bleb Leaks

To evaluate the efficacy of hyperdry amniotic membrane (AM) patching attached using a tissue adhesive for corneal perforations and glaucoma filtering bleb leaks. Prospective, noncomparative, interventional case series. Five eyes of 5 patients (glaucoma bleb leaks, 2 eyes; corneal perforations, 3 eyes) were treated with a single-layer patch of dried AM using a biological tissue adhesive. The dried AM was prepared with consecutive far-infrared rays and microwaves (hyperdry method) and was sterilized by gamma-ray irradiation. The dried AM was cut to the desired size and shape, and the tissue adhesive was applied to the amniotic epithelial side of the dried membrane. After applying the tissue adhesive, the dried membrane with glue applied then was positioned to cover the conjunctival bleb leak site or corneal perforation lesion using forceps. A therapeutic hydrogel contact lens then was installed as a bandage. Bleb leaks or corneal perforations were repaired successfully within 21 days in all 5 cases. There were no remarkable adverse effects, and there was no recurrence of bleb leak or corneal perforation. The hyperdry AM is a useful substrate, and this surgical procedure is a promising method to treat glaucoma filtering bleb leak or corneal perforation, which may result in serious vision-threatening ocular complications.

Application of amniotic membrane as xenograft for urethroplasty in rabbit

Uroepithelium repair has always been the subject of discussion in urology surgeries. Using human amniotic membrane allograft has already proved to be useful in other fields. In this study, we use amniotic membrane to repair uroepithelium injuries in rabbits. Twenty healthy rabbits underwent surgery to induce a 10-mm incision, 10 mm from the meatus on ventral part of the urethra. Then a 5 x 10 mm patch of amniotic membrane was sutured to the incised urethra. All of the rabbits were catheterized for a week and then the patches were removed. The rabbits were studied for a month for any signs of infection and fistula formation. All samples revealed complete re-epithelialization of reconstructed urethra by transitional epithelium. There was one case of infection and following fistula (5%). There were two cases of urethral strictures (10%). The result from this study suggests that amniotic membrane is an inexpensive, easy, and biodegradable graft with very little antigen effect which seems to be the ideal solution for urethroplasty.

Use of tissue adhesives in ophthalmology

Use of tissue adhesives in ophthalmology

Microsurgicai techniques in amniotic membrane patching for mild to moderate ocular surface burns

Objective To evaluate the use of amniotic membrane patches for mild or moderate eye burns at the stage of acute burns and the involved microsurgical techniques.Methods Thirty-four eyes with corneal burns of Ⅱ to Ⅲ degree in which may have partial limbal necrosis were accepted amniotic membrane patching (21 eyes) or pharmaceutical treatment (13 eyes).Four amniotic patches were procured and examined by transmitting electronic microscope when the exposed corneal surface became re-epithelialization after amniotic membrane inching.Results Amniotic patches became partially melting or prolapsed 5-10 (11± 2) days after surgery.The uncovered corneal surface showed quickly re-epithehalized.There were a few thin fibrovascular membrane invaded onto corneal surface in the patients with more than a half limbal necrosis.Postoperative visual acuity increased 1 to 6 (3.3 ± 1.2) lines.The electronic findings showed that most of the infiltrated polymorphonuclear neutrophils in the anmiotic patches became apoptosis.Corneal melting presented in four of 13 eyes who received only drug treatment and lamellar keratoplasty was then performed.The other eyes manifested pseudo-pterygium or symblepharon at different extent.Conclusion Amniotic,patches may reduce the inflammation of burned cornea and corneal neovascularization,accelerate re-epithelialization of corneal surface,even improve the rehabilitation of burned limbal stem cells. Key words: Amniotic membrane patching; Ocular surface reconstruction; Eye burns; Microsurgical technique

Conjunctival-corneal melt in association with carotid artery stenosis

To report a case of severe conjunctival-corneal melt in association with carotid artery stenosis. Observational case report. A 76-year-old man with a history of bilateral severe carotid artery occlusion and nonarteritic ischemic optic neuropathy developed a spontaneous bulbar conjunctival defect. Despite intensive lubrication, and attempts at surgical closure including an amniotic membrane patch graft, it progressed with subsequent adjacent corneal perforation. Thorough investigations revealed no underlying disease, except markedly delayed episcleral vessel filling on anterior segment fluorescein angiography. Neovascularisation is a known factor in the inhibition of ulceration. In light of the findings in this report, ocular ischemia should be considered as a cause or contributing factor in the differential diagnosis of conjunctival-corneal melt.

Temporary Sutureless Amniotic Membrane Patch for Acute Alkaline Burns

To evaluate the clinical outcome of a new sutureless approach for a temporary amniotic membrane patch (ProKera; Bio-Tissue, Inc, Miami, Florida) in eyes with acute burns. Retrospective review of 5 eyes of 5 patients with grades I to III acute alkaline burns, receiving ProKera insertion within 8 days of injury. These eyes had either total (2 cases) or extensive (60%-75%, 3 cases) corneal epithelial defects with limbal (120 degrees -360 degrees ) and conjunctival (30%-60%) epithelial defects. ProKera was inserted within a mean (SD) of 3.7 (3.1) days after burn and repeated 1 to 3 times for 3 cases. Conjunctival defects reepithelialized in 8.2 (5) days (range, 5-17 days), while limbal and corneal defects healed in 13.6 (8.3) days (range, 5-25 days). The latter was completed with circumferential closure of limbal defects followed by centripetal healing of corneal defects. In 3 eyes, early peripheral corneal neovascularization was followed by marked regression on completion of healing. During 16.8 (10.8) months of follow-up, all eyes retained a stable surface with improved corneal clarity, and without limbal deficiency or symblepharon. This sutureless application of an amniotic membrane patch allows for early delivery of its biologic actions, which may help preserve remaining limbal stem cells for rapid expansion and prevent late cicatricial complications in eyes with mild and moderate acute alkaline burns.

Ocular surface reconstruction with suspended limbal stem cells delivered by sutureless fixated amniotic membrane patch

Ocular surface reconstruction with suspended limbal stem cells delivered by sutureless fixated amniotic membrane patch

Sutureless Amniotic Membrane Transplantation for Partial Limbal Stem Cell Deficiency

To evaluate the results of sutureless amniotic membrane (AM) transplantation using fibrin glue for reconstructing corneal surfaces with partial limbal stem cell deficiency (LSCD). Retrospective noncomparative interventional case series. Eleven eyes of nine patients that had LSCD with 120 degrees to almost 360 degrees of limbal involvement underwent superficial keratectomy to remove the conjunctivalized pannus followed by AM transplantation using fibrin glue. Additional sutureless AM patch (ProKera; Bio-Tissue, Inc, Miami, Florida, USA) was used in seven patients, and mitomycin C was applied on the cornea in four eyes and during fornix reconstruction in seven eyes. The surgery was repeated in three eyes for residual pannus. During a mean follow-up of 14.2 +/- 7.7 months (range, six to 26 months), all eyes maintained a smooth and stable corneal epithelial surface without recurrent erosion or persistent epithelial defect, and showed less stromal cloudiness and vascularization. Best-corrected visual acuity improved in nine eyes (81.8%). Corneal epithelialization proceeded by epithelial growth over AM (n = 4), accompanied by dissolution of AM (n = 4) or a combination of both (n = 3). No complication was noted regarding initial or repeated uses of fibrin glue. AM transplantation using fibrin glue appears to be a safe and effective method of restoring a stable corneal epithelium for cases with partial LSCD. This approach avoids the need of transplanting limbal epithelial stem cells.

Sutureless Fixation of Amniotic Membrane Patch as a Therapeutic Contact Lens by Using a Polymethyl Methacrylate Ring and Fibrin Sealant in a Rabbit Model

To introduce and evaluate a sutureless technique by using a polymethyl methacrylate (PMMA) ring and fibrin sealant to fix an amniotic membrane (AM) patch on the ocular surface as a therapeutic contact lens in a rabbit model. PMMA rings were fabricated by duplicating an impression of a rabbit conjunctival fornix. The central cornea of the left eye in 16 rabbits was deepithelialized (diameter = 10 mm). A human AM patch was fixed to the ocular surface by using either a PMMA ring and fibrin sealant or interrupted 10-0 nylon sutures. The fibrin sealant was used to create the PMMA ring-AM complex but not to attach the AM/PMMA ring to the ocular surface. The rabbits were followed up with slit-lamp examination and fluorescein staining for 7 days. Reepithelialization and complications were recorded. The corneal epithelial defect was recovered in each rabbit of both groups after 5 days. In the sutureless group, all membranes remained in place and intact during the follow-up period. One eye was noted to have a partial conjunctival epithelial defect caused by exposure to the PMMA ring. In contrast, >50% of rabbits in the interrupted suture group exhibited complications including conjunctival edema, suture loosening, patch detachment, bleeding, and conjunctival epithelial defects. The sutureless technique that uses a PMMA ring and fibrin sealant for AM patch placement has a lower incidence of complications than the interrupted suture method. This sutureless technique may promote increased clinical use of AM patch by alleviating patients' pain and shortening surgical time.

Superficial Keratectomy and Amniotic Membrane Patch in the Treatment of Corneal Plaque of Vernal Keratoconjunctivitis

To report the importance of early surgical treatment of corneal ulcers associated with vernal keratoconjunctivitis (VKC) which may potentially produce severe lesions and permanent visual sequelae. The authors present the case of a child with corneal ulcer in plaque who did not respond to medical treatment and had a good response to surgical treatment. A superficial keratectomy with an amniotic membrane patch was performed. A rapid postoperative epithelialization with a final good visual acuity was achieved. Although amniotic membrane grafts following keratectomy have been described as a successful treatment in deep ulcers, in cases with slight stromal thinning, the amniotic membrane patch may be enough to achieve epithelialization. This procedure avoids the presence of the remains of membrane under the epithelium, which may affect postoperative corneal transparency.

Virologic and Immunologic Events in Hilar Lymph Nodes During Simian Immunodeficiency Virus Infection

To report the results of one 60 degrees conjunctival limbal autograft (CLAU) combined with amniotic membrane (AM) transplantation for an eye with total limbal stem cell deficiency (LSCD).One eye of a patient with chronic total LSCD and symblepharon caused by chemical burn was subjected to symblepharon lysis, removal of pannus from corneal surface, AM transplantation to cover the conjunctival and corneal surfaces as a permanent graft, one 60 degrees CLAU to the superior limbal area, and insertion of ProKera as a temporary AM patch to cover the CLAU.After surgery, corneal epithelialization over the AM was evident adjacent to the CLAU on day 6, progressed to pass the horizontal midline by day 11, and was completed by day 18. During a follow-up of 1 year, the corneal surface remained stable and smooth, and the stroma considerably regained clarity with regression of midstromal vascularization. The best-corrected visual acuity improved from 20/400 to 20/50. The conjunctival inflammation completely resolved, and the fornices were deep.One 60 degrees CLAU combined with AM transplantation as both a permanent graft and a temporary patch can restore the entire corneal surface in an eye with total LSCD caused by chemical burn.