Search

The amniotic membrane (AM) is the innermost part of the fetal placenta, which surrounds and protects the fetus. Due to its structural components (stem cells, growth factors, and proteins), AMs display unique biological properties and are a widely available and cost-effective tissue. As a result, AMs have been used for a century as a natural biocompatible dressing for healing corneal and skin wounds. To further increase its properties and expand its applications, advanced hybrid materials based on AMs have recently been developed. One existing approach is to combine the AM with a secondary material to create composite membranes. This review highlights the increasing development of new multilayer composite-based AMs in recent years and focuses on the benefits of additive manufacturing technologies and electrospinning, the most commonly used strategy, in expanding their use for tissue engineering and clinical applications. The use of AMs and multilayer composite-based AMs in the context of nerve regeneration is particularly emphasized and other tissue engineering applications are also discussed. This review highlights that these electrospun multilayered composite membranes were mainly created using decellularized or de-epithelialized AMs, with both synthetic and natural polymers used as secondary materials. Finally, some suggestions are provided to further enhance the biological and mechanical properties of these composite membranes.

The article reviews the main properties of the cornea and the mechanisms of its physiological regeneration and repair in response to damage and describes the most promising methods of treatment aimed at stimulating limbal stem cells and based on the use of native tissues of perinatal origin, umbilical cord mesenchymal stromal cells, and cell-free therapeutic products.

Amniotic membrane transplantation is an established therapeutic and biological adjunct for several clinical situations, including treatment of diabetic foot ulcers and ocular surface disease. However, poorly standardized and validated clinical preparation and storage procedures can render the final product highly variable and an unpredictable biomaterial. We have therefore developed a novel, standardized method for processing and dry-preserving amniotic membrane, minimizing biochemical, compositional, and structure damage to produce a potentially superior membrane suitable for clinical use. The intellectual property associated with this methodology was patented by the University of Nottingham and licensed to NuVision ® Biotherapies which formed the basis of the Tereo ® manufacturing process which is used to manufacture Omnigen ® .

Purpose: To describe a modified non-traumatic amniotic membrane transplantation (AMT) technique and evaluating its efficiency for the ocular surface injury after chemical burn were aimed., Methods: Twenty eyes of 20 patients (F: 6, M: 14) with acute chemical burn for whom modified non-traumatic AMT was utilized were evaluated retrospectively. In this technique, amniotic membrane (AM) was fixated onto a symblepharon ring with continuous suturing. The healing time of the corneal epithelial defect due to ocular surface chemical injury and melting duration of AM were evaluated. Development of infection or symblepharon, recurrence or persistence of epithelial defect, corneal perforation and the ring falling out with AM were evaluated as complications., Results: Mean age of the patients was 24.7 ± 11.7 years old (14 months-40 years). Mean duration of applying the non-traumatic AMT after contact with the chemical agent was 8.4 ± 6.2 days (2-21 days). The mean duration of the epithelial defect healing was 27.8 ± 8.8 days (11-40 days) in the grade II, III, and IV (n = 12) cases, while in the grade V and VI (n = 8) cases, a persistent epithelial defect developed, and the mean duration of the epithelial defect healing was 83 ± 23.1 days (42-120 days) (p = 0.0002). The mean melting duration of the AM was 22.7 ± 10 days (10-42 days)., Conclusion: By using this modified AMT technique, AM can be utilized efficiently, easily, and non-traumatically in every center for the treatment of the ocular surface injury due to chemical burn.

Purpose: To assess amniotic membrane retention after amniotic membrane transplant in bullous keratopathy patients and whether there were any corneal structural changes that may hinder further penetrating keratoplasty Methods: A retrospective study including 22 patients who have undergone amniotic membrane transplant from 1 Jan 1998 till 30 Jun 2016. Confocal microscopy and anterior segment optical coherence tomography (ASOCT) were performed to assess the retention of amniotic membrane and to detect any corneal structural changes. The comparison was made with 5 controls who had bullous keratopathy awaiting endothelial keratoplasty., Results: Patients had a mean follow-up of 61 ± 33.7 months. Pain reduction was significant ( p < .001) although it did not significantly correlate with the regularity of the superficial, intermediate or basal epithelial layers, nor with the retention of the amniotic membrane. No long-term structural changes that may hinder future penetrating keratoplasty were detected., Conclusion: This procedure is a safe and effective long-term treatment for symptomatic bullous keratopathy patients.

Purpose: Treatment of neuropathic corneal pain (NCP) remains intricate, and involves a long-term combined multistep approach. The self-retained cryopreserved amniotic membrane (PROKERA ® , Bio-Tissue, Miami,FL) has been utilized for multiple ocular surface disorders. We evaluate the efficacy, safety, and tolerability of ProKera ® Slim [PKS] and ProKera ® Clear [PKC] in the treatment of NCP., Methods: Retrospective case series of 9 patients who received PKS/PKC for the acute treatment of NCP. Patient demographics, prior therapies, clinical examination, duration of PKS/PKC retention, changes in pain severity, corneal subbasal nerve density and morphology by in vivo confocal microscopy (IVCM; HRT3/RCM, Heidelberg Engineering, Heidelberg, Germany), and adverse events were recorded., Results: PKS/PKC were placed in 10 eyes of 9 patients. Pain severity improved by 72.5 ± 8.4% (from 6.3 ± 0.8 to 1.9 ± 0.6, scale 1-10, p = 0.0003) after retention for 6.4 ± 1.1 days. Despite shorter retention for 4.0 ± 0.7 days in patients with ring dysesthesia (4 eyes) or premature implant disengagement (2 eyes), pain severity still improved by 63.1 ± 12.5% (from 6.8 ± 1.0 to 2.4 ± 0.9, p = 0.009). During a follow-up of 9.3 ± 0.8 months, two patients reported recurrence of pain after 2.3 and 9.6 months respectively, treated effectively with additional PKS/PKC. IVCM showed a 36.6 ± 17.6% increase in total nerve density, from 17,700.9 ± 1315.7 to 21,891.3 ± 2040.5 μm/mm 2 (p = 0.047), while the fellow PKS/PKC-untreated eyes did not show a significant interval change. Main nerve trunk and branch nerve densities were not statistically different. Dendritiform cell density decreased from 46.0 ± 8.2 to 32.0 ± 6.0 cells/mm 2 (p = 0.01)., Conclusions: PKS/PKC provide a safe and effective treatment approach to achieve sustained pain control in patients with NCP., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Objective Animal Studied Procedures Results Conclusions The application of canine amniotic membrane (cAM) for corneal reconstruction is widely used in the veterinary field. However, the information on biological properties and alternative forms of cAM for corneal wound healing is limited. This study aimed to investigate the proteomic profiles and corneal wound healing properties of cAM, cAM extract (cAME), and lyophilized cAM extract (cAMX).A total number of 14 cAMs were sterilely harvested from healthy full‐term puppies and randomly divided into three different forms: cAM (n = 14), cAME (n = 14), and cAMX (n = 14).Each form of cAMs was subjected to proteomic analysis using label‐free liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS), followed by bioinformatic analysis. The proteins were classified into properties by comparing them with the literature search on human amniotic membrane (hAM) properties and the effect on corneal wound healing when given topically.The analyses identified 8136 proteins in cAM, 8211 proteins in cAME, and 7093 proteins in cAMX. A total number of 100 proteins were matched with proteins in hAM properties and were classified into anti‐inflammatory, anti‐fibrotic, anti‐microbial, anti‐angiogenic, promotion of epithelialization, analgesic, and support cell adhesion and growth properties. Furthermore, proteins with corneal wound healing effects were identified in cAME and cAMX.cAM and its extracts contain numerous proteins, including proteins related to corneal wound healing properties. Additionally, cAME and cAMX showed proteins involved in corneal wound healing and their potential benefits for topical use in ophthalmology. [ABSTRACT FROM AUTHOR]

ObjectivesThis study aimed to define the antimicrobial peptide (AMP) expression pattern of the equine ocular surface and amniotic membrane using a targeted qPCR approach and 3'Tag-sequencing. It will serve as a reference for future studies of ocular surface innate immunity and amniotic membrane therapies.ProceduresA targeted qPCR approach was used to investigate the presence of orthologs for three of the most highly expressed beta-defensins (DEFB1, DEFB4B, and DEFB103A) of the human ocular surface and amniotic membrane in equine corneal epithelium, conjunctiva, and amniotic membrane. 3'Tag-sequencing was performed on RNA from one sample of corneal epithelium, conjunctiva, and amniotic membrane to further characterize their AMP expression.ResultsEquine corneal epithelium, conjunctiva, and amniotic membrane expressed DEFB1, DEFB4B, and DEFB103A. DEFB103A was expressed at the highest amounts in corneal epithelium, while DEFB4B was most highly expressed in conjunctiva and amniotic membrane. 3'Tag-sequencing from all three tissues confirmed these findings and identified expression of five additional beta-defensins, 11 alpha-defensins and two cathelicidins, with the alpha-defensins showing higher normalized read counts than the beta-defensins.ConclusionsThis study identified AMP expression in the equine cornea and conjunctiva, suggesting that they play a key role in the protection of the equine eye, similar to the human ocular surface. We also determined that equine amniotic membrane expresses a substantial number of AMPs suggesting it could potentiate an antimicrobial effect as a corneal graft material. Future studies will focus on defining the antimicrobial activity of these AMPs and determining their role in microbial keratitis.

The amniotic membrane (AM), the inner layer of the placenta, is a semitransparent, avascular, and thin tissue that is useful due to its structure. Amniotic membrane transplantation (AMT) avoids the need for keratoplasty to prevent corneal perforating. The purpose of the study was to evaluate the visual (gain of or no change in visual acuity) and corneal outcomes (closure of the ulcer or corneal healing) of AMT in patients with ocular surface diseases. This was a retrospective case control study (success or failure of the surgery). It was undertaken at a single academic center. The study cohort consisted of subjects with ocular surface diseases. Patients were treated with AMT for refractory ocular surface diseases. They were divided into five subgroups according to the preoperative diagnosis. The technique of AMT used was the onlay method with two layers of AM. Primary outcome measures included best corrected visual acuity (BCVA), the number of AMTs, and reepithelization of the corneal epithelium at the end of the treatment. Two weeks to six months were given to consider epithelial closure. Treatment success was defined as corneal healing within 6 months. A total of the 66 eyes of 66 patients (39 male/27 female) with a mean age of 44 ± 23 years (range 1–88 years) were included in the study. A single AMT procedure achieved epithelial closure in 74.2% (n = 49) of the eyes (53% in <15 days, 19.6% in 15–30 days, and 1.5% in 1–6 months). The fastest reepithelization occurred in neurotrophic keratopathy, 76.9% of which cases occurred within 15 days after the AMT procedure. Treatment failure was observed in five patients (7.5%), four with keratitis and one with neurotrophic keratopathy. The highest closure rates were found in persistent epithelial defects, graft-versus-host disease (GvHD), and bullous keratopathy, although there was no statistically significant difference in BCVA. Pairwise comparisons were made of neurotropic keratoplasty versus bullous keratopathy (P = 0.025), neurotrophic keratopathy versus keratitis (P = 0.004), GVHD versus keratitis (P = 0.003), and lastly, GvHD versus bullous keratopathy (P = 0.023). AMT is a safe, valuable, and fast treatment technique to treat corneal epithelial defects stemming from different etiologies that are refractory to conventional treatment. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effectiveness of cryopreserved human amniotic membrane transplantation (hAMT) in patients with infectious ulcerative keratitis. Methods: A retrospective cohort study based on medical records of patients who underwent hAMT procedure over a 2-year period (2020–2021) was conducted at Ege University Hospital, Turkey. Cryopreserved hAM was used. Best corrected visual acuity (BCVA) was measured with the Snellen chart. Detailed ophthalmological examination was performed at all visits. Treatment success was defined as complete healing including disappearance of corneal infiltrates, epithelial defect closure, reduction in anterior segment reaction. Results: A total of 13 eyes of 12 patients were diagnosed with ulcerative keratitis between 2020 and 2021. hAMT was performed in severe keratitis patients in which corneal infiltrates extending to middle to deep stromal and patients with neurotrophic component, in other words, having trouble for wound healing. The mean age was 60.9 ± 18.7 years, and 66.6% of the patients were male. Average ulcer horizontal diameter was 9.7 ± 2.8 mm. A single-layer human amniotic membrane (hAM) was transplanted 92.3% of eyes. Overlay technique was used in all patients for hAMT. The mean residence time of the amniotic membrane on the ocular surface was 14.1 ± 10.2 days. The mean time from the first presentation to the hAM transplantation was 9.7 ± 6.8 days. The average hospitalization time of all patients was 15 ± 12.1 days, pre-hAMT was 10.2 ± 7.3 days and post-hAMT was 4.8 ± 9.1 days. The mean follow-up time was 3 months. Recovery response was positive in 76.9%. Average healing time was 32.1 ± 14.04 days. Conclusions: hAMT was effective in the treatment of infectious ulcerative keratitis by accelerating and supporting wound healing. Performing hAM transplantation at the early stages of the disease and prolonged residence of membrane on the ocular surface increase the success of the treatment and moreover shortens hospitalization time. [ABSTRACT FROM AUTHOR]

Neurotrophic keratitis is a complex condition with a variety of aetiologies involving damage to the sensory nerves that innervate the cornea, resulting in potentially devastating ocular surface disease. Aetiologies include diabetes, prior herpesvirus keratitis, stroke or compressive damage to the trigeminal nerve, chronic ocular surface disease or contact lens overuse, among others. Management is multidisciplinary; of course, the underlying condition must be addressed and treated. The ocular surface must be stabilized, and depending on the severity, treatment options include artificial tears and lubrication, protective barriers (scleral lens, tarsorrhaphy), and growth factors that promote healing (serum tears, amniotic membrane). Finally, treatment can target restoration of corneal sensory innervation (cenegermin, corneal neurotization). Early recognition and treatment are important factors in reducing vision loss and long-term complications from neurotrophic keratitis. [ABSTRACT FROM AUTHOR]

Peripheral ulcerative keratitis (PUK) is an inflammatory, necrotic condition in the peripheral cornea which may end in corneal perforation and visual morbidity if not treated adequately. PUK can occur due to infectious or non-infectious causes. Early cases need medical therapy, both locally and systemically (for some cases). However, advanced PUK may necessitate surgical removal of inciting cause of the pathology and maintaining tectonic stability. Such surgical treatment, including corneal transplantations, may be used in an emergency setting or for visual rehabilitation following preliminary stabilization of the affected cornea. The outcome of these surgeries need to be analyzed to understand the long-term visual prognosis of such eyes. This is an attempt to analyze surgical modalities in the management of PUK and their outcomes. [ABSTRACT FROM AUTHOR]

Descemet's membrane endothelial keratoplasty (DMEK) may provide fast visual rehabilitation in the therapy of corneal endothelial disorders. However, due to shortage of donated corneas, how to construct a corneal endothelial substitute with powerful functions that can be used for DMEK is still unsolved. Herein, we introduced the method of corneal crosslinking (CXL) and conjugated the components of native Descemet's membrane (DM) to improve the mechanical properties and the biocompatibility of denuded amniotic membrane (dAM), further assessed their effects on cell adhesion, proliferation, YAP translocation, and metabolic activity in human corneal endothelial (HCE) cells. Using modified crosslinked dAM (mcdAM) and non-transfected HCE cells, we constructed a tissue-engineered HCE (TE-HCE) and evaluated its functions in cat and monkey models as well. Our results showed that the mechanical properties of mcdAM were improved effectively by CXL, and the adhesion, proliferation, and YAP translocation of HCE cells were dose-dependently improved after ECM modification. The combination of 0.01 mg/mL laminin with 0.1 mg/mL fibronectin showed the highest efficacy. Then, the TE-HCE was constructed in vitro , with a high density of 3612 ± 243 cells/mm2. Results of DMEK in animal models showed that corneal transparency was maintained, accompanied with normal morphology and histological structure of the regenerated corneal endothelium. Therefore, CXL combined with DM-mimic-coating methods could effectively improve the mechanical properties of dAM and enhance the biocompatibility with HCE cells. The constructed TE-HCE had normal histological structure and functioned well in animal models via DMEK, which could be used as a promising powerful equivalent of HCE. Using high-quality corneal endothelium and an appropriate endothelial keratoplasty is the most effective way for the treatment of corneal endotheliopathy. Descemet's membrane endothelial keratoplasty (DMEK) which can provide better visual acuity, lower immunological rejection rates, and improved graft survival is an ideal surgery at present. However, due to the shortage of donated corneas, it is urgent to find an equivalent substitute of corneal endothelial donor which is suitable for the DMEK surgery to solve the problem of corneal endothelial regeneration. Herein, we introduced the clinical cornea-crosslinking and Descemet's membrane-mimic-coating methods to build the modified crosslinked denuded amniotic membrane scaffold and further constructed a high-quality corneal endothelial functional substitute that can be used in DMEK surgery. [Display omitted] [ABSTRACT FROM AUTHOR]

The usage of canine amniotic membrane (cAM) is mainly of interest in veterinary ophthalmology. Topical formulations of cAM could deliver the beneficial properties of cAM without the need for surgical intervention. The present study aimed to investigate biological compositions of cAM and its extracts, including their corneal wound healing efficacy. In this study, canine amniotic membrane extract (cAME) and lyophilized canine amniotic membrane extract (cAMX) were developed. Bioactive molecules related to corneal wound healing, including hepatocyte growth factor, tissue inhibitor of metalloproteinase-1 and -2, Thrombospondin-1 and Interleukin-1 receptor antagonist were studied at both gene and protein expression levels. Cell viability and wound healing assays were investigated for the possibility of cAME and cAMX as topical applications. The results demonstrated that all of the relevant genes and proteins were detected in cAM, cAME and cAMX. Both cAME and cAMX showed wound healing properties in vitro and cAME at 1.0 mg/mL concentration appeared to have the best healing efficacy. In conclusion, cAME and cAMX generated for topical use provided promising results in the healing of corneal defects. [ABSTRACT FROM AUTHOR]

Introduction: The aim of this study was to evaluate the efficacy of sutureless amniotic membrane transplantation (SAMT) in patients with corneal perforation secondary to ocular surface inflammatory diseases. Methods: Twelve eyes of eleven patients with corneal perforation associated with Sjögren's syndrome and ocular cicatricial pemphigoid were included. Surgical procedure consisted in the application of two layers of amniotic membrane covering the corneal perforation and a therapeutic contact lens placed above the two layers, followed by sutureless tarsorrhaphy with Steri-strip applied for 15 days to immobilize the eyelids. All patients underwent slit-lamp examination, fluorescein corneal staining, and anterior segment optical coherence tomography (AS-OCT), preoperatively and post-surgery, weekly for one month, and then every two weeks for three months. Results: All 12 eyes had complete resolution of corneal perforation. Pachymetry measurements improved in all eyes, and complete healing of the corneal ulcer was obtained following treatment and maintained up to 3 months follow-up in all patients. Conclusions: SAMT was proven to be a safe and effective option for the management of inflammatory corneal perforation. The procedure is non-traumatic and easy to perform since the surgical technique is sutureless and does not require topical therapy because it takes advantage of the intrinsic properties of the membrane itself. [ABSTRACT FROM AUTHOR]

Objective: To investigate the therapeutic effects of topical equine amniotic membrane (eAM) suspension following corneal wounding in a controlled experimental setting. Procedures: Equine amniotic membrane was collected, gamma irradiated, homogenized for topical suspension preparation, and cryopreserved. Corneoscleral rims harvested from fresh rabbit globes were wounded via keratectomy and were maintained in an air‐liquid interface ex vivo corneal culture model. Treatment groups included topical gamma irradiated eAM suspension (n = 20) and a control group (n = 20). Re‐epithelialization of the wound was assessed with daily photographic evaluation of area of fluorescein uptake (mm2). Corneal wound haze after a 21‐day period was assessed by photographic analysis of haze area (mm2) and pixel intensity (0–255). Histologic processing of corneal tissue was performed, and protein identification of eAM suspension using Liquid chromatography‐mass spectrometry (LC‐MS). Results: The average day of complete corneal re‐epithelialization in controls (5.5 ± 1.1) and topically treated (5.5 ± 0.6) corneas, and rates of reduction in area of fluorescein uptake over time did not significantly differ (p =.44). The corneal wound haze was significantly reduced in mean area by approximately 52% and intensity by 57% in corneas treated with topical eAM suspension (p <.05), compared to controls 21 days following wounding. Protein analysis identified numerous proteins, specifically decorin, dermatopontin, and lumican, which have previously been documented in eAM. Conclusions: Area and intensity of corneal wound haze were significantly reduced in corneas treated with gamma irradiated eAM suspension, which may be due to previously identified therapeutic proteins which promote corneal clarity. [ABSTRACT FROM AUTHOR]

Purpose: To determine the outcome of amniotic membrane transplant in patients with ocular surface disease. Study Design: Interventional Case series study. Place and Duration of Study: Layton Rahmatullah Benevolent Trust Eye Hospital, Korangi 2½, Karachi, from January, 2019 to July 2019. Methods: Patients with an age range of 20 - 45 years, either gender and who had persistent corneal epithelial defects as a consequence of keratitis, chemical injuries, bullous keratopathy and Mooren's ulcers were included. Informed consent was obtained. Preserved amniotic membrane was used in all patients and they were followed at 1 week, 1, 3 and finally at 6 months and results were evaluated in terms of stable, healed and pain-free cornea. Results: Mean age of the patients was 37.94 ± 6.78 years. Majority of the patients (60.0%) were less than 40 years of age. Out of 58 patients, 45 (77.6%) were males and 13 (22.4%) were females. Mean duration of injury was 7.67 ± 2.28 weeks with majority of patients i.e. 62% were with less than 8 weeks of duration. Most common cause of persistent corneal epithelial defect was bacterial keratitis (17.2%) followed by vegetative trauma (13.8%). Successful surgical outcome as healed cornea was observed in 53 (91.4%) patients. Conclusion: Amniotic membrane transplant is an effective treatment for persistent corneal epithelial defects unresponsive to standard medical treatment. This surgical technique is effective in terms of healing and resolving the inflammation and preserving the useful vision. [ABSTRACT FROM AUTHOR]

Previously, we reported a collagenase-based, animal product-free protocol for cultivated oral mucosal epithelial cell sheets for transplantation (COMET). Here, we reported the long-term outcomes of first 2 clinical cases. A 27-year-old man suffered from thermal burn, which resulted in symblepharon of lower fornix OD. COMET was performed, and the cornea remained clear with few peripheral NV and no more symblepharon 34 months postoperatively. Another 42-year-old man suffered from severe alkaline burn OD. He underwent COMET, followed by corneal transplantation half a year later. A biopsy taken two years after COMET showed stratified epithelium positive for keratin 4, 13, and 3 in the suprabasal layer. Staining for p63 and p75NTR was both positive in the basal layer. The graft remained clear up to post-OP 4 years. Our study confirmed the long-term survival of the transplanted OMECs, suggesting that collagenase-based spheroidal suspension culture is a promising technique for COMET. Trial registration ClinicalTrials.gov, ClinicalTrials.gov ID: NCT03943797 Registered 9 May 2019-Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT03943797. [ABSTRACT FROM AUTHOR]

Objective: To describe the surgical repair of traumatic complete spectaculectomy and keratomalacia in a snake. Animals: A 10.5‐year‐old, female, Boelen's python (Simalia boeleni) was presented with iatrogenic, near‐complete spectaculectomy associated with bacterial keratitis, keratomalacia, and hypopyon. Procedures: Corneal samples for cytological evaluation and bacterial culture were collected. Following medical stabilization of the bacterial keratitis, a double‐layered dry amniotic membrane graft was placed. The first amniotic membrane layer was placed over the cornea with the edges tucked under the peripheral remnants of the spectacle and secured in place with fibrin glue. The second amniotic membrane layer was placed over the entirety of the spectacle remnant and secured in place with a combination of fibrin glue and sutures. Topical and systemic antimicrobials, topical ophthalmic lubricants, and systemic non‐steroidal anti‐inflammatory therapy were administered postoperatively. Results: Heterophilic keratitis was identified by cytology and Enterobacter cloacae, Pseudomonas aeruginosa, and Staphylococcus sciuri were cultured from the corneal samples. The amniotic membrane grafts remained in place for several weeks. At 4 months postoperatively, the spectacle was completely regenerated, the subspectacular space restored, and the cornea was transparent. Spectacular vascularization and fibrosis then slowly cleared over the following 6 months. Conclusions and clinical relevance: Amniotic membrane grafting with fibrin glue is a relatively simple and effective surgical method to reconstruct extensive defects in the reptilian spectacle and to assist in the management of bacterial keratitis associated with spectacle avulsion. [ABSTRACT FROM AUTHOR]

[Display omitted] • An ultrathin bilayer membrane is fabricated from amniotic membrane and silicon. • Bilayer membrane reveals a decreased degradation and improved mechanical property. • Silicon layer makes bilayer membrane suturable with increased transparency. • Silicon/amniotic bilayer membrane improves rabbit corneal epithelial defects. Amniotic membrane (AM) is an effective and widely used dressing in ocular injuries to reconstruct the cornea. Due to its low mechanical strength, high biodegradation rate, and difficult handling, its usage in medical interventions remains challenging. In this study, decellularized AM was covered with an ultrathin layer of Polydimethylsiloxane (PDMS) through a spinning method, which in turn resulted in an ultrathin (less than 80 µm in thickness) bilayer corneal wound dressing membrane with improved mechanical behavior and transparency. The biomechanical, biological, and antibacterial properties of the bilayer membranes were measured both in vitro and in vivo. The optimized microsized membrane was applied on a corneal defect wound created in a rabbit model to evaluate the corneal healing. The results demonstrated a significant decrease in degradation rate, improved mechanical properties, and AM/PDMS transparency compared with AM. The corneal transparency improved until 21 days post-surgery in AM/PDMS group. Histological evaluations revealed that AM/PDMS had better epithelial delaminated cell morphology. The results of the RT-PCR showed a significant increase in MMP9, a significant decrease in Col1A1, TGF-β1, TNF-α and IL-6 in both AM and AM/PDMS compared with control wounds. This study suggessts AM/PDMS membrane as an excellent corneal wound dressing. [ABSTRACT FROM AUTHOR]

Investigation of the superiority of the usage of propolis extract, amniotic membrane transplantation, corticosteroid and antibiotic both separately and in different combinations was aimed. A total of 40 (20 male, 20 female) New Zealand breed rabbits weighing 2.5-3.0 kg were used in the study. The rabbits were divided into 5 groups on day 7 of alkali burn injury. Amniotic membrane transplantation was applied to 3 groups and each one of these 3 groups had different local medications as 1% water-based propolis extract (AMN+PRP), dexamethasone and tobramycin (AMN+AC) and only tobramycin (AMN+A). The other two groups, which were not performed amniotic membran transplantation, were either treated with propolis (PRP) or left as a control. The defect area results obtained from AMN+PRP group were lower than AMN+A group, and both AMN+PRP and control group at the day 9 and day 14, respectively (P≤0.05). In the measurements made after the second week, AMN+PRP group showed significantly better results in all weeks in terms of defect area (P≤0.05). Corneal thickness was found to be lower in all groups treated with amniotic membrane than in the other groups (P

The usage of canine amniotic membrane (cAM) is mainly of interest in veterinary ophthalmology. Topical formulations of cAM could deliver the beneficial properties of cAM without the need for surgical intervention. The present study aimed to investigate biological compositions of cAM and its extracts, including their corneal wound healing efficacy. In this study, canine amniotic membrane extract (cAME) and lyophilized canine amniotic membrane extract (cAMX) were developed. Bioactive molecules related to corneal wound healing, including hepatocyte growth factor, tissue inhibitor of metalloproteinase-1 and -2, Thrombospondin-1 and Interleukin-1 receptor antagonist were studied at both gene and protein expression levels. Cell viability and wound healing assays were investigated for the possibility of cAME and cAMX as topical applications. The results demonstrated that all of the relevant genes and proteins were detected in cAM, cAME and cAMX. Both cAME and cAMX showed wound healing properties in vitro and cAME at 1.0 mg/mL concentration appeared to have the best healing efficacy. In conclusion, cAME and cAMX generated for topical use provided promising results in the healing of corneal defects.

Introduction: The aim of this study was to evaluate the efficacy of sutureless amniotic membrane transplantation (SAMT) in patients with corneal perforation secondary to ocular surface inflammatory diseases. Methods: Twelve eyes of eleven patients with corneal perforation associated with Sjögren’s syndrome and ocular cicatricial pemphigoid were included. Surgical procedure consisted in the application of two layers of amniotic membrane covering the corneal perforation and a therapeutic contact lens placed above the two layers, followed by sutureless tarsorrhaphy with Steri-strip applied for 15 days to immobilize the eyelids. All patients underwent slit-lamp examination, fluorescein corneal staining, and anterior segment optical coherence tomography (AS-OCT), preoperatively and post-surgery, weekly for one month, and then every two weeks for three months. Results: All 12 eyes had complete resolution of corneal perforation. Pachymetry measurements improved in all eyes, and complete healing of the corneal ulcer was obtained following treatment and maintained up to 3 months follow-up in all patients. Conclusions: SAMT was proven to be a safe and effective option for the management of inflammatory corneal perforation. The procedure is non-traumatic and easy to perform since the surgical technique is sutureless and does not require topical therapy because it takes advantage of the intrinsic properties of the membrane itself.

Amniotic membrane (AM) has been shown to enhance corneal wound healing due to the abundance of growth factors, cytokines, and extracellular matrix (ECM) proteins inherent to the tissue. As such, AM has garnered widespread clinical utility as a biological dressing for a number of ophthalmic and soft tissue applications. The preparation, sterilization, and storage procedures used to manufacture AM grafts are extremely important for the conservation of inherent biological components within the membrane. Current processing techniques use harsh chemicals and sterilization agents that can compromise the fundamental wound healing properties of AM. Furthermore, commercially available cryopreserved AM products require specific storage conditions (e.g., ultra-low freezers) thereby limiting their clinical availability in austere environments. Supercritical carbon dioxide (SCCO2) technology allows for the sterilization of biological tissues without the resulting degradation of integral ECM proteins and other factors often seen with current tissue sterilization processes. With this study we demonstrate that lyophilized AM, sterilized using SCCO2, maintains similar biochemical properties and biocompatibility as that of commercially available AM products requiring specialized cold storage conditions. [ABSTRACT FROM AUTHOR]

Objectives: This paper aims to examine the efficacy, safety, and long term outcomes of amniotic membrane transplantation for corneal surface reconstruction, in cases of limbal stem cell deficiency. Material and methods: A systematic literature search was performed on PubMed, for papers published up to February 2020, using the following combined search terms: "limbal stem cell deficiency", "amniotic membrane", "limbal transplant". Only clinical trials with human subjects were selected for analysis. We collected the data on amniotic membrane properties and mechanisms of action, processing, preservation and transplantation techniques, and clinical outcomes of different treatment methods. Results: The surgical approach for treating limbal stem cell deficiency depends on the extent of the disease. Isolated amniotic membrane transplantation appears to have a limited beneficial effect on limbal stem cells, whereas amniotic membrane transplantation, combined with certain types of limbal stem cell transplantation, provides long-term biological and mechanical support for the donor tissue explants. Combined with simple limbal epithelial transplantation, the amniotic membrane has shown excellent results in the surgical management of limbal stem cell deficiency. Conclusions: Preliminary results of amniotic membrane use in limbal transplantation show quite satisfactory data, but the lack of high-level randomized controlled studies makes it difficult to assess the comparative efficacy of amniotic membrane transplantation in limbal stem cell deficiency surgical management.

Background: Surgical treatment of pterygium can result in corneal topographic changes. It is not clear that those changes are universal or technique dependent. Objectives: Evaluation of corneal topographic changes following pterygium surgery using sutured conjunctival autografting versus sutured amniotic membrane grafting. Patients and methods: In this prospective randomized study, patients suffering from primary pterygia that extend between two and four millimeters over the cornea were included. Patients were separated into group I; underwent pterygium excision with sutured conjunctival autograft, and group II underwent pterygium excision with sutured amniotic membrane graft after a comprehensive ophthalmic examination. The following topographic parameters were noted: the axial curvature map, elevation posterior map, and corneal thickness map. Results: Significant improvement of the mean visual acuity measured using the logMAR test was found in both groups postoperatively. The improvement included UCVA and BCVA as well as anterior keratmetric and cylindrical power of the cornea without significant dissimilarity between study groups. No statistically considerable changes in the posterior corneal surface or the corneal thickness were found. Conclusions: Pterygium excision can cause changes in the keratmetric and cylindrical power of the cornea without the affection of the posterior corneal surface or the corneal thickness. The corneal topographic changes caused by the pterygium were not varied with the type of surgical technique used. [ABSTRACT FROM AUTHOR]

Aim: The aim of this paper is to provide a succinct literature review of the different clinical applications for AMT usage in an ophthalmic setting, ranging from commonly used applications to less mainstream approaches. The hope is that this review enables the reader to have a better understanding of the biological properties of amnion as well as the indications and scenarios in which AMT can be used, whilst presenting relevant evidence from within the literature which may be of interest. We also provide an update on the methods of preservation of amniotic membrane and the application methodologies. Methods: Literature search. A PubMed search was performed using the search terms "amniotic membrane transplant", "amnion AND cornea", amnion AND ophthalmology", "amnion AND ocular surface" and "Amnion AND eye". A full review of the literature using the PubMed database was conducted up until 01/05/20. The articles used were written in English, with all articles accessed in full. Both review articles and original articles were used for this review. All full publications related to ophthalmology were considered. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this study was to describe the short-term results of allogenic transplantation of limbal stem cells expanded on amniotic membrane for the ocular surface reconstruction. Methods: Prospective nonrandomized, nonmasked study in a single ophthalmological center. Ten patients with bilateral total limbal stem cell deficiency (LSCD) were included. Expression and presence of ABCB5 and Δp63α in amniotic membrane-cultured limbal epithelial stem cells were analyzed, in relationship with clinical changes after allogenic transplantation. An objective evaluation was performed to determine corneal transparency and superficial vascularization. Results: In a median follow-up time of 11.6 months, 7 patients (70%) were considered as failure compared with the preoperative status. ABCB5 and Δp63α are expressed in similar amount in the limbal epithelial cells expanded in vitro and transplanted in patients with bilateral LSCD. Conclusions: Transplantation of allogenic epithelial limbal cells expanded in amniotic membrane could be considered in patients with LSCD due to burns or congenital etiologies such as aniridia, but its benefit is limited for patients with immunologic diseases. [ABSTRACT FROM AUTHOR]

Investigation of the superiority of the usage of propolis extract, amniotic membrane transplantation, corticosteroid and antibiotic both separately and in different combinations was aimed. A total of 40 (20 male, 20 female) New Zealand breed rabbits weighing 2.5-3.0 kg were used in the study. The rabbits were divided into 5 groups on day 7 of alkali burn injury. Amniotic membrane transplantation was applied to 3 groups and each one of these 3 groups had different local medications as 1% water-based propolis extract (AMN+PRP), dexamethasone and tobramycin (AMN+AC) and only tobramycin (AMN+A). The other two groups, which were not performed amniotic membran transplantation, were either treated with propolis (PRP) or left as a control. The defect area results obtained from AMN+PRP group were lower than AMN+A group, and both AMN+PRP and control group at the day 9 and day 14, respectively (P=0.05). In the measurements made after the second week, AMN+PRP group showed significantly better results in all weeks in terms of defect area (P=0.05). Corneal thickness was found to be lower in all groups treated with amniotic membrane than in the other groups (P<0.05). This study aimed to find treatment effectiveness of combining the amniotic membrane with propolis, especially as an anti-inflammatory agent comparing to corticosteroids, and it was decided the outcomes can be improved on the further studies. [ABSTRACT FROM AUTHOR]

Background: To evaluate new indicators in the efficacy of amniotic membrane transplantation (AMT) for non-healing corneal ulcers (NHCUs). Methods: Retrospective, multicenter study. In total, 223 AMTs for NHCU in 191 patients were assessed. The main outcomes studied were the success rate of AMT (complete re-epithelization), postoperative visual acuity (VA) gain, and number of AM layers transplanted. Results: The overall AMT success rate was 74.4%. In 92% of our patients VA stability or improvement. Postoperative VA was significantly higher than preoperative VA in the entire cohort (p < 0.001) and in all etiological groups of ulcers (post-bacterial, p ≤ 0.001; post-herpetic, p ≤ 0.0038; neurotrophic ulcers, p ≤ 0.014; non-rheumatic peripheral, p ≤ 0.001; and ulcers secondary to lagophthalmos and eyelid malposition or trauma, p ≤ 0.004). Most participants (56.5%) presented a preoperative VA equal to or less than counting fingers (≤0.01). Of these, 13.5% reached a postoperative VA equal to or better than legal blindness (≥0.05) after AMT. A higher success rate was observed in the monolayer than in the multilayer AMT (79.5% and 64.9%, respectively; p = 0.018). No statistically significant values were found between the number of layers transplanted and VA gain (p = 0.509). Conclusion: AMT is not only beneficial in achieving complete re-epithelialization in NHCUs but also in improving postoperative VA; these improvements are independent of etiologies of ulcers. Furthermore, the use of monolayer AMT seems to be a more appropriate option than multilayer AMT for NHCU since the multilayer AMT did not present better outcomes (success rate and VA gain) compared to monolayer AMT in the different types of ulcers studied.

In our experimental study we evaluated the efficacy of human freeze-dried amniotic membrane on healing of corneal wound defect in dogs. A corneal wound was performed by using corneal trephine 8.5 mm in diameter. A total of 14 dogs were divided into two groups of 7 dogs in each: (A) Control group; (B) AM group treated by transplantation of freezedried human amniotic membrane in conjunction with a third eyelid flap. Clinical outcome was monitored by evaluation of epiphora, ocular discharge, corneal vascularization, corneal opacity and corneal epithelization at the 7th, 11th, 15th and 30th days post-surgery. Fluorescein staining was used to estimate the closure of the corneal wounds. Histopathological examination was performed in two dogs of each group; the thickness of the newly generated cornea was measured by using Image j analysis software. The control group was complicated with severe neovascularization, ocular discharge and corneal opacity. There were excessive thickness in the stroma of control group as reflect of inflammatory reaction. The AM group showed mild degree vascularization which was completely absent by the end of experiment. Corneal epithelialization was completed within 15 days after the transplantation in the AM group. In conclusion, transplantation of human amniotic membrane improves canine corneal epithelial wound healing effectively. [ABSTRACT FROM AUTHOR]

Gelareh S Noureddin, Sonia N Yeung Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, BC, Canada Abstract: Pterygium is a fibrovascular growth of the bulbar conjunctiva that crosses the limbus and extends over the peripheral cornea, in some cases resulting in significant visual morbidity. When treatment is indicated, surgery is necessary, and several management options exist. These include excision, conjunctival autografting, and the use of adjuvant therapies. This paper reviews the incidence and prevalence of pterygia and also describes the various techniques currently used to treat this condition. These management options are compared to the use of dry amniotic membrane grafting (AMG), specifically with regard to recurrence rates, time to recurrence, safety and tolerability, as well as patient factors including cosmesis and quality of life. AMG has been used in the treatment of ocular surface disease due to a variety of benefits, including its anti-inflammatory properties, as well as its ability to promote epithelial growth and suppress transforming growth factor-β signaling and fibroblast proliferation. However, rates of recurrence for AMG following pterygium excision still surpass other commonly used techniques, including conjunctival and limbal autografting. Nevertheless, there are circumstances in which AMG may be most beneficial to the patient, such as when preexisting conjunctival scarring is present, when the conjunctiva must be spared for future glaucoma filtering surgery, or in cases of large or double-headed pterygia. Therefore, surgeons should be prepared to offer this procedure as an option to their patients for the treatment of pterygia. Keywords: cornea, pterygium, amniotic membrane, conjunctival autograft

Purpose. To evaluate long-term results of intrastromal amniotic membrane implantation in patients with induced endothelial epithelial dystrophy (EED) of cornea. Material and methods. The clinical study included 50 patients (50 eyes) with a diagnosis of secondary corneal EED of the far-advanced stage. All patients underwent the surgery of intrastromal implantation of amniotic membrane (IIAM) in the cornea.Results. The obtained data in the course of the study showed a slight, statistically significant increase of visual acuity in the operated patients. On admission of patients the visual acuity averaged 0.01±0.005, 24 months after the IIAM – 0.03±0.01 (p

Copyright of Der Ophthalmologe is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The objective of this research was to evaluate the clinical and microscopic effects in rabbits of lamellar keratoplasty using allogeneic omentum associated with canine amniotic membrane (AM). Rabbits were divided into two groups: one received the allogeneic free omental graft covered with the AM (OM-graft group), while the other received the AM graft containing omental mesenchymal cells (OM-cell group). Clinical signs were evaluated on different postoperative days. After the clinical assessments, the rabbits were euthanized and their corneas were obtained for histopathology and immunohistochemistry (Ki- 67, marker for proliferation). Both groups showed chemosis, blepharospasm, eye discharge, hyperemia, and corneal opacity/ edema. Neovascularization was observed in the OM-cell group. Histopathological evaluation revealed epithelial islands within the stroma of OM-cell samples. Thirty days after surgery, complete corneal re-epithelialization had occurred in both groups. The OMcell group showed more Ki-67 positive cells. The free omentum and its cells, combined with the AM, contributed to corneal repair, a process that was completed 30 days after lamellar keratoplasty. [ABSTRACT FROM AUTHOR]

Se realizó una revisión bibliográfica con el objetivo de conocer la utilidad de la membrana amniótica como alternativa de tratamiento en la superficie ocular. Son abordados tópicos como las diferentes formas de obtención, preparación y conservación de la misma, sus mecanismos de acción y aplicaciones. Se consultó una bibliografía que abarca un periodo de varios años para conocer los resultados publicados sobre el trasplante de membrana amniótica humana en la superficie ocular.A literature review was made to learn about the usefulness of the amniotic membrane as a therapeutic option for the ocular surface. The different ways for obtaining, preparing, and conserving this membrane, its mechanism of action and its applications were also addressed. Literature covering several years was reviewed in order to be acquainted with the published results of the human amniotic membrane transplantation on the ocular surface.

Realizou-se a ceratectomia superficial em 28 coelhos, distribuídos em dois grupos. No grupo tratado, composto por 14 animais, utilizou-se a membrana amniótica canina como bandagem, suturada com sua face epitelial voltada contra a superfície corneana. O grupo controle não recebeu tratamento. A avaliação clínica foi realizada 24 horas após a cirurgia, a cada dois dias durante uma semana e a cada quatro dias até 180 dias. Avaliaram-se os efeitos da membrana amniótica como bandagem, comparando-se o tempo de epitelização da córnea entre os grupos e verificando o período necessário para que a córnea apresentasse transparência completa. A opacidade corneana esteve presente em todos os animais durante o período observado. O tratamento instituído resultou clinicamente em neovascularização corneana, opacidade de córnea mais intensa no período inicial de reparação, retardou o processo de epitelização e causou mais dor e desconforto que nos animais do grupo-controle.Twenty-eight rabbits were submitted to superficial keratectomy. The treated group consisted of 14 animals received canine amniotic membrane as a bandage, sutured in a way that its epithelial surface was in contact with the corneal surface. The control group did not receive any treatment. The animals were submitted to clinical evaluations 24 hours after surgery, at each two-day interval during one week and at each four-day interval during 180 days. The amniotic membranes were evaluated as a bandage comparing the time needed for corneal epithelization in the treated and non-treated groups and determining the period necessary for the cornea to become completely transparent. The corneal opacity was present during the entire time of observation. The treated animals presented more opaque cornea in the early period of regeneration, with neovascularization and more pain and discomfort than the animals from control group, showing a delayed epithelization.

The objective of the study was to evaluate the topical effects of 0.2% Cyclosporine A (CsA) on corneal neovascularization of rats following surgical implantation of equine amniotic membrane into a corneal stroma micropocket. The implantation of xenologous amniotic membrane was performed bilaterally in 90 rats. In the same day of the surgery each right eye started receiving topical CsA twice a day. The left eye received no medication and served as a control. The evaluation of corneal neovascularization was performed by computerized image analysis and histopathological evaluation at 1, 3, 7, 15, 30 and 60 days postoperatively. For the image analysis 10 animals were used per time period, and for the histopathological examination, five animals were used per time period. Image analysis found that corneal neovascularization began on the 3rd postoperative day, reached its peak on the 7th day, and then progressively and rapidly decreased. Statistic analysis indicated that neovascularization of the CsA treated eye on the 7th day was significantly higher than that observed in untreated eyes. On the 30th day, however, this pattern was reversed with the neovascularization observed in the CsA treated eyes declining to the low levels observed on the 3rd day. The degree of neovascularization in the untreated eyes on the 30th day declined to the baseline levels found on day 3 at the 60th day. Histopathological analysis indicated that deposition of collagen in the implanted tissue was completed by the 15th day. Therefore, we concluded that (1) equine amniotic membrane in rat corneal stroma produced an intense neovascularization until the 15th day postoperatively and then regressed, (2) deposition of collagen of the implanted tissue was completed on the 15th day postoperatively, and (3) use of CsA was associated with increase in the corneal neovascularization initially, followed by a quick and intense regression.Este estudo teve como objetivo a avaliação dos efeitos tópicos da Ciclosporina a 0,2% (CsA) sobre a neovascularização corneana de ratos após implante cirúrgico de membrana amniótica eqüina em microbolsa do estroma corneana. O implante da membrana foi feito bilateralmente em 90 ratos. O tratamento com CsA iniciou-se no mesmo dia da cirurgia, nos olhos direitos dos animais, duas vezes ao dia. Os olhos esquerdos não receberam nenhum tratamento e serviram de controle. A avaliação da neovascularização corneana foi feita por análise de imagem computadorizada e por exame histopatológico aos dias 1, 3, 7, 15, 30 e 60 de pós-cirúrgico. Para a análise de imagem foram utilizados 10 animais por período, e para o exame histopatológico, 5 por período. A análise de imagem demonstrou que a neovascularização iniciou-se no 3° dia pós-cirúrgico, alcançou seu pico no 7° dia e então regrediu rápida e progressivamente até o 60° dia. A análise estatística indicou que a neovascularização no 7º dia nos olhos tratados com CsA foi significantemente mais acentuada do que aquela observada nos olhos não tratados. Entretanto, no 30º dia este fato se reverteu, e a neovascularização observada nos olhos tratados com CsA diminuíra a níveis baixos comparáveis àquela do 3º dia. Já nos olhos não tratados, o grau de neovascularização somente pôde ser comparado àquele nível básico encontrado no 3º dia aos 60 dias de pós-operatório. A análise histopatológica demonstrou que a deposição de colágeno no tecido implantado se completou no 15º dia. Desta maneira, foi possível concluir que (1) a membrana amniótica em estroma corneano de ratos produz intensa neovascularização até o 15º dia de pós-operatório com posterior regressão, (2) a deposição de colágeno do tecido implantado foi completa ao 15º dia de pós-operatório, e que (3) o uso de CsA esteve associado com aumento inicial da neovascularização corneana, seguido de rápida e intensa regressão.

Avaliaram-se as alterações relacionadas à deficiência das células límbicas precursoras do epitélio corneano de coelhos e o efeito da membrana amniótica sobre sua cicatrização. A lesão, induzida com n-heptanol associado à peritomia conjuntival em 360°, foi recoberta com membrana amniótica canina, suturada à episclera perilímbica, criopreservada em meio para congelação de embrião ou em meio próprio, ambos com glicerol a 50% e mantida a -80°C. O grupo-controle não foi tratado com a membrana. As avaliações histológicas foram realizadas ao sétimo, 15º e 30º dias. Todos desenvolveram deficiência de células germinativas do limbo, denominada conjuntivalização, com presença de neovascularização, inflamação e defeitos epiteliais recorrentes, caracterizada na histopatologia pela presença de neovasos, edema, leucócitos e células caliciformes. O transplante de membrana amniótica não foi eficiente para o tratamento desta deficiência, entretanto auxiliou o processo de cicatrização da córnea.Changes related to limbal stem cells deficiency in corneal epithelium in rabbits, as well as the results of amniotic membrane transplant on the cicatrisation were evaluated. The ulcer was induced with n-heptanol associated to 360° conjunctival peritomy; the corneal surface was covered with canine amniotic membrane, sutured to perilimbal episclera, cryopreserved in embryo solution or own medium, both with 50% glycerol and stored at -80°C. The control group was not treated with membrane. Histological evaluations were performed at seven, 15, and 30 days. All of them developed limbal stem cells deficiency, named conjunctivalization, with neovascularization, inflammation and recurrent epithelial defects, observed in histopathology by the occurrence of neovascularization, edema, leukocytes and goblet cells. Thus amniotic membrane transplantation was not efficient in the treatment of limbal stem cells deficiency, however it helped in the process of cicatrisation.

Avaliaram-se, por meio da análise clínica, histopatologia e imunoistoquímica, os efeitos da aplicação da membrana amniótica xenógena fresca e conservada em glicerina, sobre os mecanismos imunológicos da superfície ocular. Para tal, utilizaram-se 40 coelhos, distribuídos em dois grupos experimentais, os quais foram avaliados por 21 dias. A avaliação clínica revelou que a membrana amniótica xenógena conservada em glicerina estimulou uma resposta inflamatória aguda maior que a membrana aplicada fresca. A análise histopatológica indicou que ambas se comportaram de forma semelhante a partir da primeira semana de pós-operatório, apresentando as alterações clássicas da resposta inflamatória da córnea, com o predomínio de infiltrado do tipo polimorfonuclear. A análise imunoistoquímica indicou que, ainda aos 21 dias, a resposta imune local é inespecífica, permitindo concluir que a resposta imune específica na córnea é tardia e que a córnea é um sítio privilegiado para aplicação de enxertos com características imunológicas diferentes, visto que não houve o estímulo para o desenvolvimento de uma resposta mais específica nos grupos avaliados durante toda a execução do experimento.The dynamics of the inflammatory response and the mechanism involved in the healing process of cornea treated by keratoplasty, applying fresh and glycerin preserved xenogenous amniotic membranes as method to cover experimental ulcers were studied using 40 rabbits. The animals were allotted into two groups and evaluated during 21 days. The eyes were evaluated by histopathological study and immunohistochemical reaction. The clinical evaluation showed that the xenogenous amniotic membrane preserved in glycerin stimulated a greater acute inflammatory response than the one caused by fresh membrane. The histopathological analysis indicated that both membranes reacted in a very similar way from the first week post-surgery, presenting the classical alterations of the inflammatory response on the cornea. The immunohistochemical technique indicated that in no moment of the observation, the local immunologic response was specific. It was concluded that the specific immunologic response on the cornea took place later and that is a privileged site to use grafts with different immunological characteristics, once there was not a stimulus to the development of a more specific response in none of the evaluated groups throughout the experiment.

OUR PURPOSE IS TO REPORT TWO CASES OF ACUTE ALKALI EYE BURN TREATED WITH AMNIOTIC MEMBRANE PATCH. BECAUSE THE OCULAR BURNS WERE RECENT WE PATCHED THE EYE IN THE ACUTE PHASE WITH AMNIOTIC MEMBRANE. BY THIS APPROACH THE AMNIOTIC MEMBRANE SERVES AS GROWTH PROMOTING AND ANTI INFLAMMATORY AGENT. ALTHOUGH AT THE BEGINNING THE LIMBUS AND THE CORNEA OF BOTH PATIENTS WERE AFFECTED, AFTER THE INTEGRATION OF THE AMNIOTIC MEMBRANE, WITH PROPER TREATMENT, NO FURTHER SURGICAL TREATMENT WAS NEEDED, WITH 100% VISUAL ACUITY RECOVERY. THE AMNIOTIC MEMBRANE REPRESENTS A POSSIBLE TREATMENT IN OCULAR BURNS NOT ONLY IN THE CHRONIC PHASE, FOR BURNS GRADE 3 OR 4 WITH LIMBAL STEM CELL DEFICIENCY, BUT ALSO IN THE ACUTE PHASE. [ABSTRACT FROM AUTHOR]

The purpose of this study was to assess the long-term outcome of patients with symptomatic bullous keratopathy after amniotic membrane transplant. A retrospective cohort study includes that 20 patients with symptomatic bullous keratopathy, who have underwent amniotic membrane transplant at the Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Prince of Wales Hospital & Alice Ho Miu Ling Hospital, Hong Kong between 04/1998 and 06/2011, were invited back. Clinical examination was performed, including, pain score assessment (pain score out of 10), epithelial healing, and vision. A total of 21 eyes of 20 patients returned for our study. The majority of eyes experienced pain reduction (94 %), with a significant mean pain score difference of 6.8 ± 2.6, 2-tail p < 0.001 (99 % CI 4.9-8.7). The mean pre-operative and post-operative pain scores were 7.3 ± 2.9 and 0.5 ± 1.0, respectively. 16 eyes (76 %) were completely pain free, and 10 eyes (47 %) remained symptom free after a mean follow-up of 39.0 ± 36.3 months (range 5-171 months). The median epithelial healing time was 2 weeks (range 1-20 weeks). Amniotic membrane transplant may be considered as a longer-term treatment for bullous keratopathy patients, especially in patients with poorer visual prognosis, but it may also be used as an interim measure for patients awaiting corneal transplant. [ABSTRACT FROM AUTHOR]

OUR PURPOSE IS TO REPORT TWO CASES OF ACUTE ALKALI EYE BURN TREATED WITH AMNIOTIC MEMBRANE PATCH. BECAUSE THE OCULAR BURNS WERE RECENT WE PATCHED THE EYE IN THE ACUTE PHASE WITH AMNIOTIC MEMBRANE. BY THIS APPROACH THE AMNIOTIC MEMBRANE SERVES AS GROWTH PROMOTING AND ANTI INFLAMMATORY AGENT. ALTHOUGH AT THE BEGINNING THE LIMBUS AND THE CORNEA OF BOTH PATIENTS WERE AFFECTED, AFTER THE INTEGRATION OF THE AMNIOTIC MEMBRANE, WITH PROPER TREATMENT, NO FURTHER SURGICAL TREATMENT WAS NEEDED, WITH 100 % VISUAL ACUITY RECOVERY. THE AMNIOTIC MEMBRANE REPRESENTS A POSSIBLE TREATMENT IN OCULAR BURNS NOT ONLY IN THE CHRONIC PHASE, FOR BURNS GRADE 3 OR 4 WITH LIMBAL STEM CELL DEFICIENCY, BUT ALSO IN THE ACUTE PHASE. [ABSTRACT FROM AUTHOR]