The amniotic membrane (AM) has a long history of use in the treatment of various diseases of the ocular surface. It contains pluripotent cells, highly organized collagen, anti-fibrotic and ...anti-inflammatory cytokines, immune-modulators, growth factors, and matrix proteins. It is used to promote corneal healing in severely damaged eyes. Recently, AM extract and AM extract eye drops have been successfully used in clinical applications, including dry eye and chemical burns. We provide an overview on the recent progress in the preparation, mechanisms of action, and use of AM extract/AM extract eye drops for corneal and external eye diseases.
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.
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.
The human amniotic membrane (HAM) collagen matrix derived from human placenta can be decellularized (dHAM) to form a natural biocompatible material. dHAM has different bioactive substances and has ...been used widely in human tissue engineering research. However, dHAM has some disadvantages, e.g., poor mechanical properties, easy degradation and inconvenient operation and use, so it is not conducive to large-area or full-thickness skin defect healing. To overcome these limitations, for the first time, dHAM was grafted with methacrylic anhydride (MA) to form photocrosslinked dHAM methacrylate (dHAMMA); dHAMMA was then blended with methacrylated gelatin (GelMA), followed by the addition of a photosensitizer for photocrosslinking to obtain the fast-forming GelMA-dHAMMA composite hydrogel. Further, GelMA-dHAMMA was found to have the porous structure of a bicomponent polymer network and good physical and chemical properties. In vitro experiments, GelMA-dHAMMA was found to promote fibroblast proliferation and α-smooth muscle actin (α-SMA) expression. In vivo investigations also demonstrated that GelMA-dHAMMA promotes wound collagen deposition and angiogenesis, and accelerates tissue healing. GelMA-dHAMMA inherits the good mechanical properties of GelMA and maintains the biological activity of the amniotic membrane, promoting the reconstruction and regeneration of skin wounds. Thus, GelMA-dHAMMA can serve as a promising biomaterial in skin tissue engineering. STATEMENT OF SIGNIFICANCE: Since the early 20th century, the human amniotic membrane (HAM) has been successfully used for trauma treatment and reconstruction purposes. dHAM has different bioactive substances and has been used widely in human tissue-engineering research. In this work, the dHAM and gelatin were grafted and modified by using methacrylic anhydride (MA) to form photocrosslinked dHAMMA and methacrylated gelatin (GelMA). Then, the dHAMMA and GelMA were blended with a photosensitizer to form the GelMA-dHAMMA composite hydrogel derived from gelatin-dHAM. GelMA-dHAMMA exhibits a bicomponent-network (BCN) interpenetrating structure. dHAM dydrogel has advantages, e.g., good mechanical properties, slow degradation and convenient operation, so it is conducive to large-area or full-thickness skin defect healing.
Background: Biological materials derived from decellularized tissues could be a good basis for progress in regenerative medicine while maintaining the main components of the extracellular matrix. A ...promising scaffold for tissue-engineered is the human amniotic membrane. It is one of the oldest biomaterials used for scaffolds. Material and methods: 3 placentas were obtained through Human Tissue Bank. Under sterile condition human amniotic membrane was collected. The human amniotic membrane was treated with 0.5% of sodium dodecyl sulphate (SDS), 1% Triton for 24 and 5 hours. Amniotic membrane decellularization was also carried out in combination with ultrasound bath for 20 minutes 3 times. For morphological and structure evaluation of human amniotic membrane the scanning electron microscopy of native amniotic membrane and histology of decellularized and native amniotic membrane were performed. Results: The human amniotic membrane decellularization process with 0.5% SDS solution and 1% Triton solution showed that decellularization for 24 hours is too aggressive for human amniotic membrane structure. The decellularization for 5h with 1% Triton solution was incomplete. Conclusions: The method of decellularization with 0.5% SDS solution is more suitable for amniotic membrane decellularization and can be performed in only 5 hours. The use of ultrasound bath did not have a significant effect on the obtained results.
Human amniotic membrane (hAM) has been employed as scaffolding material in a wide range of tissue engineering applications, especially as a skin dressing and as a graft for corneal treatment, due to ...the structure of the extracellular matrix and excellent biological properties that enhance both wound healing and tissue regeneration. This review highlights recent work and current knowledge on the application of native hAM, and/or production of hAM‐based tissue‐engineered products to create scaffolds mimicking the structure of the native membrane to enhance the hAM performance. Moreover, an overview is presented on the available (cryo) preservation techniques for storage of native hAM and tissue‐engineered products that are necessary to maintain biological functions such as angiogenesis, anti‐inflammation, antifibrotic and antibacterial activity.
Objective
To examine the safety and efficacy of hyperdry amniotic membrane (HDAM) for wound closure after palatoplasty in cleft palate patients.
Methods
HDAMs were prepared by washing and drying ...under infrared rays and microwaves at temperatures less than 60°C using a hyperdrying device. A total of 16 cleft palate patients (8 males, 8 females), aged 1 to 3 years (mean age 1 year 9 months), received one-stage pushback palatoplasty. The remaining raw wound after surgery was covered by an HDAM and a plastic cover plate. The cover plate was removed 1 week after surgery and parameters including temperature, feeding, allergic reactions, postoperative bleeding, re-epithelialization, wound dehiscence, and infection were monitored during the follow-up period of 31.2 months.
Results
All patients could adequately ingest at 5 days postoperation and after removal of the cover plate. None of the patients had a persistent fever or allergic reactions. Ingestion was feasible immediately in all patients, and no postoperative bleeding was observed during ingestion. No secondary hemorrhages were observed during follow-up. No postoperative wound dehiscence on the midline of the palate was observed. No infections were observed after the removal of the cover plate. No patients suffered from severe scar formation or contracture of the wound in the follow-up period. Hemorrhage, undue epithelialization, and scar contracture did not occur in any patient. The mean evaluation score was 7.75 points.
Conclusion
HDAM can be used safely and effectively for wound closure following palatoplasty in cleft palate infants. Future studies testing the safety of patient's own amnion for palatoplasty, are required.
Extracellular matrix‐based bio‐scaffolds are useful for tissue engineering as they retain the unique structural, mechanical, and physiological microenvironment of the tissue thus facilitating ...cellular attachment and matrix activities. However, considering its potential, a comprehensive understanding of the protein profile remains elusive. Herein, we evaluate the impact of decellularization on the human amniotic membrane (hAM) based on its proteome profile, physicochemical features, as well as the attachment, viability, and proliferation of umbilical cord‐derived mesenchymal stem cells (hUC‐MSC). Proteome profiles of decellularized hAM (D‐hAM) were compared with hAM, and gene ontology (GO) enrichment analysis was performed. Proteomic data revealed that D‐hAM retained a total of 249 proteins, predominantly comprised of extracellular matrix proteins including collagens (collagen I, collagen IV, collagen VI, collagen VII, and collagen XII), proteoglycans (biglycan, decorin, lumican, mimecan, and versican), glycoproteins (dermatopontin, fibrinogen, fibrillin, laminin, and vitronectin), and growth factors including transforming growth factor beta (TGF‐β) and fibroblast growth factor (FGF) while eliminated most of the intracellular proteins. Scanning electron microscopy was used to analyze the epithelial and basal surfaces of D‐hAM. The D‐hAM displayed variability in fibril morphology and porosity as compared with hAM, showing loosely packed collagen fibers and prominent large pore areas on the basal side of D‐hAM. Both sides of D‐hAM supported the growth and proliferation of hUC‐MSC. Comparative investigations, however, demonstrated that the basal side of D‐hAM displayed higher hUC‐MSC proliferation than the epithelial side. These findings highlight the importance of understanding the micro‐environmental differences between the two sides of D‐hAM while optimizing cell‐based therapeutic applications.
We report a case of severe burn injury in a 42-year-old pregnant patient referred to our hospital's burn unit after experiencing a scald burn injury that burned her neck, chest, trunk, abdomen and ...limbs. The patient had burn wounds distributed on her neck, all four extremities, the chest and abdomen, with a total burn area of 46.5%. The burn wounds were treated with surgical debridement and then covered with silver sulfadiazine and damp gauze. The patient's wounds were treated every three days. The patient delivered a healthy baby full-term through a spontaneous, vaginal delivery. After delivery, the amniotic membrane from the patient was used as an amniotic membrane graft and was planted on the patient's chest, right arm and right thigh. The amniotic membrane in this patient helped to accelerate the preparation of the wound bed for skin grafting. Split-thickness skin grafts were then used on the wounds and the patient was discharged from the hospital one week later. Patients that present with burn injuries during pregnancy require intense monitoring and careful management from a multidisciplinary team. A collaborative effort needs to be made in order to plan the best outcome for the mother and fetus. Precise and early resuscitation is the first step to treating such cases. The administration of fluids should be titered based on the patient's hemodynamic condition and urine output. Wound management can also be optimized using the amniotic membrane as a temporary dressing before skin grafting.
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