Human Amniotic Membrane Graft Research Articles

Staining and Sizing Technique for Human Amniotic Membrane Graft in Refractory Macular Holes.

Purpose: To describe the triple S technique for aiding the visualization (staining), preparation (sizing), and placement (sliding) of human amniotic membrane grafts in cases of refractory macular holes (MHs). Methods: Brilliant blue-green dye was used to stain the graft before insertion for improved visualization and to aid in its orientation. Preoperative optical coherence tomography-based sizing of the graft was performed, and a dermal trephine was used to fashion the graft according to size. Once placed in the eye, the graft was positioned by bimanually sliding it into the MH using a nitinol loop and a Tano brush. Results: Seven eyes of 7 patients had repair of a refractory MH. Anatomic closure was successful in all patients with no postoperative displacement or dislodgement of the graft. The mean logMAR (±SD) visual acuity was 1.80 ± 0.4 preoperatively and 1.27 ± 0.6 at the final follow-up. Conclusions: The triple S technique provided adequate visualization, sizing, and placement of amniotic membrane grafts in cases of refractory MHs. This modification may help reduce the learning curve associated with this technique.

Management of Corneal Ulcers using Autologous Serum, Platelet Rich Plasma and Processed Human Amniotic Membrane in Dogs

Background: In dogs the corneal ulcers are one of the major ophthalmic emergencies and can cure with routine medications, but in delay presentation will become challenge for veterinarians. In such cases advanced therapeutic management such as serum, platelet reach plasma and corneal grafts are needed for favorable outcome. Methods: The present study was conducted on 24 dogs (29 eyes) with corneal ulcer categorized as a superficial (Group-I, n=15), deep corneal ulcers (Group-II, n=8) and descemetocele (Group-III, n=6) which were treated with autologous serum, Platelet Rich Plasma and Processed decellularized human amniotic membrane grafting, respectively. All the affected eyes were given routine topical medications with eye drops Moxifloxacin, Flurbiprofen q.i.d till healing, 1% Atropine sulphate b.i.d for 5 days and Oral Doxycycline was given @ 5 mg/kg b.i.d for 10 days. Result: The group-I (n=11, 15 eyes) treated with autologous serum eight to ten times-a-day as per severity with routine medication. Two dogs with entropion which was corrected first. The eyes gained vision within 10th-15th days. Developed complications managed medicinally till complete recovery. The group-II (n=7, 8 eyes) treated with platelet rich plasma drops five to seven times-a-day with routine medication. 75% eyes recovered up to 45th day. Developed complication were managed medicinally till complete recovery. The group-III (n=5, 6 eyes) treated with Decellularized Processed Human Amniotic Membrane Graft. 4 eyes gained complete transparency on 28th day of therapy while in 2 eyes developed complication were managed medicinally.

Combined Amniotic Membrane Graft and Autologous Retinal Transplant for Repair of Refractory Chronic Myopic Macular Holes

Purpose: To report a technique for reconstruction of large, persistent, chronic, myopic macular holes using a combined human amniotic membrane graft and autologous retinal transplant (AMN-ART). Methods: Three patients with large, myopic macular holes that failed prior surgical attempts and underwent subretinal amniotic membrane graft with overlying autologous retinal transplant and short-term perfluorocarbon tamponade. Pre- and postoperative visual acuity (VA) and images were analyzed at 3, 6, and 9 months. Results: All 3 myopic macular holes remained closed at 9 months with resolution of central scotoma. The first case, a 69-year-old female, presented with a persistent macular hole whose minimum linear diameter was 1085 μm. Her pre-op VA of 20/200 improved by 9 months to 20/100. Secondly, a 72-year-old male with history of recurrent retinal detachment repair with silicone oil and persistent macular hole of 1134 μm presented with pre-op VA of 20/200, which was unchanged at 9 months. Lastly, a 76-year-old female with a persistent macular hole of 935 μm with preop VA of 20/80 improved by 9 months post-op to 20/50. No complications were encountered related to the grafts. Conclusion: Combined AMN-ART may provide a surgical option for repair of refractory, large, chronic myopic macular holes with underlying atrophy.

Acellular human amniotic membrane: A safe and stable matrix for corneal stromal regeneration

Amniotic membrane (AM) transplantation is used as a safe and effective method to treat a variety of ocular complications. On the ocular surface, this membrane degrades within a few days. This study investigated the safety and long-term stability of human amniotic membrane (HAM) grafts in the corneal stroma. Three rabbits with healthy eyes underwent unilateral stromal pocketing with implantation of decellularized HAM (dHAM). Examinations of graft bio-integration were performed by corneal imaging using slit lamp and optical coherence tomography (OCT) at 1 week, 3 months, and 9 months. The thickness of the thickest part of the amniotic membrane was 187 μm at the first follow-up, 184 μm at 3 months, and 166 μm at 9 months. Histological evaluation was performed after the last follow-up. The results showed no clinical complications, such as opacity, neovascularization, infection, or rejection. The thickness of the grafts remained stable over time. Histopathological analyses showed the grafts were integrated into the corneal stroma without any inflammation. This study indicated that HAM was a naturally safe, stable, and compatible matrix in the corneal stroma and was considered a promising candidate for corneal stromal regeneration.

PRETREATED LYOPHILIZED HUMAN AMNIOTIC MEMBRANE GRAFT COVERING FOR RETINAL DETACHMENT WITH POSTERIOR RETINAL BREAKS ABOVE CHORIORETINAL ATROPHY IN PATHOLOGIC MYOPIA.

To compare the surgical results of vitrectomy with untreated or pretreated lyophilized human amniotic membrane grafts covering in treating retinal detachment related to posterior retinal breaks above chorioretinal atrophy in pathologic myopia. Nineteen patients with retinal detachment related to macular hole (MH) located above macular atrophy and/or posterior paravascular retinal breaks (PRBs) located above patchy chorioretinal atrophy in pathologic myopia were included. The eyes of these patients underwent vitrectomy with untreated lyophilized human amniotic membrane covering (n = 10) or perfluorocarbon liquid (PFCL)-assisted pretreated lyophilized human amniotic membrane covering (n = 9; grafts were pretreated in 0.125% indocyanine green and 50% hypertonic glucose solution for 15-20 minutes). The closure of the MH or PRBs, reattachment of the retina, and best-corrected visual acuity were measured postoperatively. Postoperatively, graft dislocation or shift was only found in two eyes (20%) in the untreated group. The closure rate of the MH or PRBs was 80% (8/10) and 100% (9/9) in the untreated group and the pretreated group, respectively. The occurrence rate of excessive gliosis was 40% and 11% in the untreated group and the pretreated group, respectively. In both groups, best-corrected visual acuity was improved and the retinal reattachment rate was 100% at the final visit. Perfluorocarbon liquid-assisted pretreated lyophilized human amniotic membrane graft covering was effective in treating retinal detachment related to MH and/or PRBs situated above macular atrophy or patchy chorioretinal atrophy in pathologic myopia. This technique appeared to reduce graft dislocation or shift, promote the closures of MHs/PRBs, and reduce the occurrence of gliosis.

Macular Hole Hydrodissection Technique with Human Amniotic Membrane for Repair of Large Macular Holes.

To describe a combined surgical technique utilizing the Macular Hole Hydrodissection (MHH) with human amniotic membrane (hAM) for repair of large macular holes. A step-by-step procedure and a surgical video using the combined MHH and hAM technique are presented. As the first step, the MHH separates the adhesions of the macular hole to the underlying retinal pigment epithelium (RPE) with a soft tipped cannula through proportional reflux followed by gentle passive aspiration. The hAM graft is marked to identify the non-sticky epithelial side and ensure that the stromal layer (sticky and non-shinny) is facing downward towards the RPE. The graft is then tucked into the space created with MHH between the macular hole edges and the RPE with closed forceps to decrease the likelihood of the graft from dislocating post-operatively. The MHH in combination with the hAM is a practical and effective technique for addressing challenging large macular holes.

In vitro and ex vivo characterization of nanonized amniotic membrane particles: An untapped modality for ocular surface reconstruction

The pristine Human Amniotic Membrane (HAM) has portrayed outstanding potential as scaffold for ocular surface reconstruction and regeneration. However, in treatment procedures where the supporting membrane matrix of HAM is not obligatory and only the bioactive molecules are vital, the surgical practise of HAM grafting causes redundant trauma and economic burden to the patient. Hence, in our laboratory we have attempted to break down HAM to nanoscale particles and validate its potential as a competent ocular therapeutic agent; by conducting a comparative analysis between the fresh, lyophilized, micronized and Nanonized Amniotic Membrane (NAM) particles. Our results evidently showcased that the prepared NAM particles was <100 nm and the major biomolecules such as collagen and hyaluronic acid were well retained. Further, the NAM particles eluted significantly higher amounts of proteins and growth factors while maintaining its stability and isotonicity when stored at 4 °C. Its biostability was assayed in the presence of lysozyme enzyme. Its remarkable ability to promote cell proliferation in rabbit corneal cells and negative cytotoxicity is an added advantage for ocular application. The ocular biocompatibility of NAM, evaluated by the ex vivo assessment of corneal thickness, transparency, histopathology, immunohistochemistry and corneal permeability clearly indicated its suitability for ophthalmic applications.

THE LONG-TERM FOLLOW-UP OF AUTOLOGOUS BLOOD CLOT-ASSISTED LYOPHILIZED HUMAN AMNIOTIC MEMBRANE COVERING TREATMENT UNCLOSED MACULAR HOLE.

The objectives were to assess the long-term morphologic and functional outcome of eyes with unclosed macular hole (MH) in which the internal limiting membrane has been peeled in previous vitrectomy with autologous blood clot-assisted lyophilized human amniotic membrane (LhAM) graft covering. Twelve eyes with MH unclosed in previous surgery were selected and studied. Autologous blood clot-assisted LhAM graft was used to cover the MH in vitrectomy. The main clinical outcomes including best-corrected visual acuity, closure of MH, and the outcome of LhAM graft were recorded. The mean minimum diameter of the MH was 641.7 ± 245.9 µ m and the mean axial length was 27.3 ± 3.50 mm. The LhAM graft was maintained in the former position and all the MH closed in 10 eyes, whereas the graft slipped and the MH unclosed in two eyes. The MH closure rate was 83.3% and the mean best-corrected visual acuity improved significantly from 1.47 ± 0.58 logMAR (Snellen 20/590) preoperatively to 1.17 ± 0.60 logMAR (Snellen 20/296) postoperatively. During 18 to 36 months follow-up, LhAM grafts were attached to the retinal surface in nine eyes, detached from the retinal surface in one eye, dislocated from the fovea in one eye, and inserted into the retina in one eye; and macular atrophy occurred in one eye. Autologous blood clot-assisted LhAM graft covering provided a simple and effective treatment option for unclosed MH and reduce surgical trauma. Although the graft remained on the macular surface for a long time, it did not affect the recovery of MH and postoperative vision.

Surgical classification for large macular hole: based on different surgical techniques results: the CLOSE study group

BackgroundThe CLOSE study group proposes an updated surgical classification for large macular holes based on a systematic review of new treatments. Recently, many new techniques have been introduced to treat large full-thickness macular holes (FTMH); although the indications are not clear. An updated surgical classification is needed to help surgical decision-making.MethodsWe gathered published series by the CLOSE Study Group members and from literature search until June 2021. Techniques included: internal limiting membrane peeling (ILM peeling), ILM flaps, macular hydrodissection (macular hydro), human amniotic membrane graft (hAM), and autologous retinal transplantation (ART). Within each technique, chi-square test assessed association between the minimal linear diameter (MLD) (in µm) and closure rate; the postoperative best-corrected visual acuity (BCVA) gains were compared among groups.ResultsData extraction included 31 published articles: total of 1135 eyes. Eyes were divided into the following groups: ILM peel (n: 683), ILM Flap (n: 233), macular hydrodissection (n: 64), hAM (n: 59), and ART (n: 96). The initial BCVA and size were heterogenous between the groups. ILM peel showed the best results in large FTMH ≤ 535 µm (closure rate 96.8%); adjusted mean BCVA: 0.49 (LogMAR) with a statistical difference among groups. Large FTMH between 535 and 799 µm: ILM flap technique showed better results (closure rate 99.0%); adjusted mean BCVA: 0.67(LogMAR); also with a statistical difference. For large FTMH ≥ 800 µm more invasive techniques are required. Use of hAM, macular hydrodissection and ART showed higher closure rates for this category (100%, 83.3% and 90.5% respectively), and adjusted mean BCVA varied from 0.76 to 0.89. Although there was no statistical difference between those techniques for this group due to the smaller number of cases.ConclusionsThe CLOSE study group demonstrated the potential usefulness of a new surgical classification for large FTMHs and propose OCT biomarkers for use in clinical practice and future research. This new classification demonstrated that Large (400–550 µm) and X-Large (550–800 µm) holes can be treated highly successfully with ILM peel and ILM flap techniques, respectively. Further studies are necessary for the larger FTMHs (XX-Large and Giant), using the CLOSE classification, in order to determine which technique is better suited for each hole size and characteristics.

Keratin films for ocular surface reconstruction: Wound healing in an in-vivo model

The most commonly used tissue substitute for ocular surface reconstruction is human amniotic membrane (AM). Because of its low biomechanical strength and intransparency there is a need to search for alternatives of consistent quality. This study, further explored the biocompatibility of Keratin Film (KF) and its ability to sustain corneal epithelial wound healing.In three equal groups of 5 New Zeeland white rabbits a 4 mm superficial keratectomy was created in the right eye. Five eyes received a KF, five a human AM graft and the remaining five no implant. All eyes were treated with ofloxacin and dexamethasone eye drops and followed up for 10 days. Corneal fluorescein staining, vascularization, and transparency were assessed using slit lamp biomicroscopy according to a standardized grading score during and at the end of follow-up. The corneal-scleral-button was excised and processed for histology.After 10 days all eyes which had received a KF showed complete epithelial healing and no signs of neovascularization. In the AM group 1 eye showed a persistent epithelial defect at day 10 and 2 eyes showed neovascularization at day 7 resolving at day 10. Transparency improved progressively both in the KF group as well as in the AM group towards the end of the follow. Histology showed a multilayer epithelium firmly adherent to the KF with no evidence of keratocyte migration or inflammatory reaction in the corneal stroma.In this study on rabbit eyes KF better supported corneal epithelial wound healing than amniotic membrane.

Human amniotic membrane as a dural substitute in neurosurgery: A systematic review

Several studies have highlighted the use of human amniotic membrane (HAM) in neurosurgical procedures as an effective dural substitute. HAM has inherent antifibrotic and anti-inflammatory properties and exhibits immunomodulatory effect that makes it an ideal dural substitute. Other advantages including easy availability, low cost of procurement, and storage also render it a promising dural substitute especially in low- and middle-income countries. A systematic literature search was performed using PubMed, Scopus, and Google Scholar databases, using the search terms "human amniotic membrane," "dural repair," and "neurosurgery." To be eligible for inclusion in our review, papers had to report primary data, be published in English language and report dural repair on humans with human amniotic membrane. Eligibility assessment was conducted by two independent reviewers with qualitative analysis on the basis of surgical utility, postoperative complications, and histological analysis. Eight articles met the predefined inclusion criteria, including three randomized control trials and five cohort studies. We evaluated the use of HAM grafts in dural repair for elective cranial surgery (four studies), trauma surgery (three studies), and elective spine surgery (one study). Cases with postoperative cerebrospinal fluid (CSF) leak were reported by two studies. Other postoperative complications including meningitis, hydrocephalus, pseudomeningocele, CSF collection in subdural space, and subacute subdural hematoma were reported by one study each. Postsurgical histological analysis was reported by three studies highlighting the antiadhesive and integrative properties of HAM. The current review of evidence suggests that in terms of postsurgical outcomes, HAM is comparable with commercially available dural substitutes.

Retraction Note: Human amniotic membrane grafts for retinal breaks in diabetic tractional retinal detachment and combined tractional and rhegmatogenous retinal detachment

Retraction Note: Human amniotic membrane grafts for retinal breaks in diabetic tractional retinal detachment and combined tractional and rhegmatogenous retinal detachment

The Potential Role of Human Derived Amniotic Membrane Graft in The Repair of Induced Tendon Tear in Adult Male Albino Rat: Histological Study

Abstract Introduction Achilles tendon tears cause severe impairment in patient mobility and productivity, causing significant reduction in the quality of life. Many complications are associated with the tendon healing process such as peritendinous adhesions and excessive fibrotic scars. Unsatisfactory results appeared with the existing medical and surgical treatments to regain full tendon structure and function. Amniotic membrane is avascular, and characterized by low immunogenicity, anti-inflammatory, antiscarring properties. These criteria render it as a natural biological substitute and a novel therapeutic alternative for tendon tears. Aim: The aim of the work was to study the effect of human amniotic membrane graft application on the repair of induced Achilles tendon tear. Material and methods Fresh human amniotic membrane (AM) grafts were prepared from harvested human full-term caesarian sections-delivered placentas. Thirty adult male albino rats were divided into 3 equal groups (n = 10); group I (control group), group II (tendon tear group) and group III (AM treated group). After anesthesia, a full thickness transverse incision was induced in the rat right Achilles tendons of group II and III. Human derived amniotic membrane graft measuring 1 cm2 was applied circumferentially on the tendon tear in group III. Rats were sacrificed after 28 days. Results After the tendon tear, the untreated group (II) showed gradual accumulation of fat cells replacing the collagen bundles in focal areas. Areas of mononuclear cellular infiltration were demonstrated. The AM-treated group showed many thick parallel regularly arranged collagen fibers with a significant increase in the collagen fibers area percentage. It also showed apparent increase in tenoblasts with regular organization and apparent decrease of mononuclear inflammatory cells. Conclusion This study demonstrated the potential therapeutic role of the application of human amniotic membrane grafts in the repair of Achilles tendon tears, suggesting a future alternative therapy for patients suffering from Achilles tendon tears.

Efficacy of Ipsilateral, Focal-Simple Limbal Epithelial Transplantation for Large Primary Nasal Pterygia Treatment

Purpose: The long-term success of pterygium surgery is subject to treatment of the limbal stem cell defect. The purpose of this study is to present an alternative method to conjunctival autografting in patients with large pterygia and consequently a large limbal stem cell defect. Methods: 38 Patients with primary nasal pterygium of more than 5 mm limbal involvement were selected for the procedure. Simple limbal epithelial transplantation with human amniotic membrane graft placement over the bare sclera after pterygium excision was done. Patients were followed-up for a period of 12 months. Results: From post-operative day 7, patients had significant improvement in complaints and ocular surface morphology. We reported only one case of graft failure which was a consequence of patient’s non-compliance with post-operative medications and follow-up. Conclusion: Focal-simple limbal epithelial transplantation is an effective alternative to conjunctival limbal autografting in patients with large pterygia where preservation of virgin conjunctiva is prudent for future ocular surgeries.

Human amniotic membrane for the treatment of large and refractory macular holes: a retrospective, multicentric, interventional study

BackgroundThe purpose of the current study is to report the anatomical and functional results of off-label human amniotic membrane graft as primary intervention to repair large to giant macular holes and in reoperations when wide internal limiting membrane peeling was unsuccessful.MethodsRetrospective chart review was carried out in five different centers to identify all cases that had undergone off-label human amniotic membrane graft for the treatment of large or failed macular holes (MH). Data collected included age, gender, other concomitant diagnosis, symptoms duration, lens status, number of previous surgeries, macular hole measurements (minimum and base linear diameters), mean post-operative follow-up (months), and pre- and post-operative best corrected visual acuity (BCVA). Main outcome measures were anatomical MH closure rates and final BCVA (in logMAR). Nonparametric Wilcoxon rank-sum test was used because the data was not normally distributed, a P values < 0.05 were considered statistically significant.ResultsNineteen eyes of 19 patients were identified and included in the study. Mean age was 66.21 ± 14.96 years and predominantly females (84%). All eyes had successfully closed MH with a single intervention with no recurrences during a mean of 9 ± 3.87 months follow-up. The median BCVA in logMAR preoperative was 1.30 ± 0.44 (0.80–2.0), approximately 20/400 on Snellen chart and the median BCVA in logMAR postoperative was 1.0 ± 0.72 (0.4–3.0) approximately 20/200 (p < 0.0001) with median of three lines of visual improvement.ConclusionThe use of human amniotic membrane graft seems to be a viable and effective alternative for the treatment of large and persistent macular holes. However, further larger prospective controlled studies are necessary to confirm our preliminary results of this new surgical technique.

RETRACTED ARTICLE: Human amniotic membrane grafts for retinal breaks in diabetic tractional retinal detachment and combined tractional and rhegmatogenous retinal detachment

To describe the surgical outcomes of using human amniotic membrane (hAM) grafts in the management of retinal breaks in diabetic tractional detachment (TRD) and combined tractional and rhegmatogenous retinal detachment (CTRRD). A retrospective case series of 10 eyes with TRD or CTRRD receiving pars plana vitrectomy with hAM grafts implantation, compared with 13 controls receiving the same surgery without hAM grafts. Best-corrected visual acuity (BCVA) and re-detachment rate were compared between two groups. Postoperatively, all eyes in the hAM group had retina attachment without recurrence, while 9 eyes in the control group had retina re-detachment and required additional surgery (0% vs 69.2%, p = 0.003). The BCVA significantly improved in the hAM group (from 1.96 ± 0.95 to 1.44 ± 0.77 in log MAR, p = 0.03), but not improved in control group (p = 0.20). Postoperative optical coherence tomography of the eyes receiving hAM grafts demonstrated glial tissue regeneration and restoration of ellipsoid zone. In diabetic TRD or CTRRD, hAM grafts could be an effective method, with promising outcome. Compared to standard surgery, it could result in higher retina reattachment rate and significant visual improvement. Moreover, it may offer the adjunctive benefit in tissue regeneration and fasten ellipsoid zone restoration.

Mesenchymal stem cells' seeded amniotic membrane as a tissue-engineered dressing for wound healing.

Different biomaterials have been used as biological dressing for wound regeneration. For many decades, human amniotic membrane graft (AM) has been widely applied for treating acute and chronic wounds. It has minimal toxicity and immunogenicity, supports mesenchymal cell in-growth, improves epidermal cell adherence and proliferation, and finally is inexpensive and readily available. Enrichment of tissue grafts with the stem cells is a new approach to improve their regenerative effects. This animal study aimed at investigating feasibility, safety, and efficacy of tissue-engineered dressings composed of AM and two different types of mesenchymal stem cells (MSCs) in the excisional wound model in rats. Human adipose-derived MSCs (ADMSCs) and placenta-derived MSCs (PLMSCs) were manufactured from the donated adipose and placenta tissues respectively. After cell characterization, MSCs were seeded on acellular AM (AAM) and cultivated for 5days. Excisional wound model was developed in 24 male Wistar rats that were randomly classified into four groups including control, AAM, ADMSCs + AAM, and PLMSCs + AAM (n = 6 in each group). Tissue-engineered constructs were applied, and photographs were taken on days 0, 7, and 14 for observing the wound healing rates. In days 7 and 14 post-treatment, three rats from each group were euthanized, and wound biopsies were harvested, and histopathologic studies were conducted. The results of wound closure rate, re-epithelialization, angiogenesis, and collagen remodeling demonstrated that in comparison with the control groups, the MSC-seeded AAMs had superior regenerative effects in excisional wound animal model. Between MSCs group, the PLMSCs showed better healing effect. Our data suggested that seeding of MSCs on AAM can boosts its regenerative effects in wound treatment. We also found that PLMSCs had superior regenerative effects to ADMSc in the rat model of excisional wound.

Parafoveal atrophy after human amniotic membrane graft for macular hole in patients with high myopia

PurposeTo report the surgical outcome and postoperative hypopigmented change around fovea among patients with high myopia who received human amniotic membrane (hAM) graft transplantation for macular hole (MH).MethodThis retrospective, interventional...

Comparison between Cryopreserved and Dehydrated Human Amniotic Membrane Graft in Treating Challenging Cases with Macular Hole and Macular Hole Retinal Detachment.

Purpose To evaluate the surgical outcomes of cryopreserved and dehydrated human amniotic membrane (hAM) graft transplantation for macular hole (MH) and macular hole retinal detachment (MHRD) repair. Materials and Methods This retrospective, interventional case series was conducted in two hospitals. Two types of hAM grafts, namely, the dehydrated form (AmnioGen, HCT Regenerative, Taiwan) and the cryopreserved form (AmnioGraft, Bio-Tissue, Miami, FL), were consecutively used in MH surgeries. Anatomical and functional outcomes between the 2 types of hAM grafts were compared. Results Seventeen patients (mean age: 62.1 ± 10.0 years, 9 (52.9%) males) were enrolled. Of them, 11 patients had persistent MH, 3 had MH without prior surgery, and 3 had MHRD. A cryopreserved hAM graft was used in 10 patients, and a dehydrated hAM graft was used in 8 patients. One patient used a cryopreserved hAM in the first MH surgery and a dehydrated hAM in the second surgery for extramacular hole with retinal detachment. After a 6-month follow-up, 13 (76.5%) patients had sealed MHs. The average visual acuity (VA) of cases with sealed MHs improved from 1.38 ± 0.62 to 1.12 ± 0.47 logMAR (p=0.03). In the other 4 cases with persistent MH, 3 had graft dislocation and 1 had a reopened MH with graft contraction. There were no significant differences in closure rate (80.00% vs. 71.43%, p=0.68) or VA improvement (0.19 ± 0.37 logMAR vs. 0.15 ± 0.41 logMAR, p=0.85) between the 2 kinds of hAM graft. Conclusion This preliminary case series showed that both cryopreserved hAM and dehydrated hAM are feasible alternative grafts for either persistent or recurrent MH. Both approaches have similar anatomical and functional outcomes.

Design of Experiment, Preparation, and in vitro Biological Assessment of Human Amniotic Membrane Extract Loaded Nanoparticles.

Human amniotic membrane grafting could be potentially useful in ocular surface complications due to tissue similarity and the presence of factors that reduce inflammation, vascularization, and scarring. However, considerations like donor-derived infectious risk and the requirement of an invasive surgery limit the clinical application of such treatments. Moreover, the quick depletion of bioactive factors after grafting reduces the efficacy of treatments. Therefore, in the current study, the possibility of nano delivery of the bioactive factors extracted from the human amniotic membrane to the ocular surface was investigated. Nanoparticles were prepared using polyelectrolyte complexation from chitosan and dextran sulfate. The effect of polymer ratio, pH, and the amount of extract on particle size and encapsulation efficacy were studied using Box-Behnken response surface methodology. The optimum condition was obtained as follows: 4.9:1 ratio of dextran sulfate to chitosan, 600 µL amniotic membrane extract, and pH of 6. The prepared nanoparticles had an average size of 213 nm with 77% encapsulation efficacy. In the release test, after 10 days, approximately 50% of entrapped bioactive proteins were released from the nanocarriers in a controlled manner. Biological activity assessment on endothelial cells revealed amniotic membrane extract loaded nanoparticles had a longer and significant increase in anti-angiogenic effect when compared to the control. Our data elucidate the ability of nanotechnology in ocular targeted nano delivery of bioactive compounds.