Bone marrow–derived mesenchymal stem cells (BMSCs) have been used for allogeneic application in tissue engineering but have certain drawbacks. Therefore, stem cells (SC)s derived from other adult tissue sources have been considered as an alternative. However, there is only limited knowledge on their immunomodulatory properties. The aim of our study was to compare the immunomodulatory potential of human amniotic mesenchymal and human amniotic epithelial cells with that of human adipose-derived SCs under identical experimental conditions. We have demonstrated a dose-dependent inhibition of peripheral blood mononuclear cell (PBMC) immune responses in mixed lymphocyte reactions (up to 66–93% inhibition) and phytohemagglutinin activation assays (up to 67–96% inhibition). The lowest SC-to-PBMC ratio able to inhibit PBMC proliferation significantly was 1:8. Subcultivation (passage 2–6) did not alter immunoinhibitory properties, whereas cryopreservation significantly reduced the immunomodulatory potential. Using ...

Dose-dependent immunomodulatory effect of human stem cells from amniotic membrane: a comparison with human mesenchymal stem cells from adipose tissue.

Treatment of large bone defects represents a great challenge in orthopedic and craniomaxillofacial surgery. Although there are several methods for bone reconstruction, they all have specific indications and limitations. The concept of using barrier membranes for restoration of bone defects has been developed in an effort to simplify their treatment by offering a sinlge-staged procedure. Research on this field of bone regeneration is ongoing, with evidence being mainly attained from preclinical studies. The purpose of this review is to summarize the current experimental and clinical evidence on the use of barrier membranes for restoration of bone defects in maxillofacial and orthopedic surgery. Although there are a few promising preliminary human studies, before clinical applications can be recommended, future research should aim to establish the 'ideal' barrier membrane and delineate the need for additional bone grafting materials aiming to 'mimic' or even accelerate the normal process of bone formation. Reproducible results and long-term observations with barrier membranes in animal studies, and particularly in large animal models, are required as well as well-designed clinical studies to evaluate their safety, efficacy and cost-effectiveness.

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The role of barrier membranes for guided bone regeneration and restoration of large bone defects: current experimental and clinical evidence

Cultured epithelial autograft (CEA) in burn treatment: Three decades later

https://shadyhayek.com/wp-content/uploads/2012/02/New-technologies-for-burn-wound-closure-and-healing%E2%80%94Review-of-the-literature.pdf

New technologies for burn wound closure and healing--review of the literature.

The use of amniotic membrane in ophthalmic surgery and other surgical procedures in the fields of dermatology, plastic surgery, genitourinary medicine and otolaryngology is on the increase. Furthermore, amniotic membrane and its epithelial and mesenchymal cells have broad use in regenerative medicine and hold great promise in anticancer treatment. Amniotic membrane is a rich source of biologically active factors and as such, promotes healing and acts as an effective material for wound dressing. Amniotic membrane supports epithelialization and exhibits anti-fibrotic, anti-inflammatory, anti-angiogenic and anti-microbial features. Placentas utilised in the preparation of amniotic membrane are retrieved from donors undergoing elective caesarean section. Maternal blood must undergo serological screening at the time of donation and, in the absence of advanced diagnostic testing techniques, 6 months postpartum in order to cover the time window for the potential transmission of communicable diseases. Amniotic membrane is prepared by blunt dissection under strict aseptic conditions, then is typically transferred onto a nitrocellulose paper carrier, usually with the epithelial side up, and cut into multiple pieces of different dimensions. Amniotic membrane can be stored under various conditions, most often cryopreserved in glycerol or dimethyl sulfoxide or their mixture with culture medium or buffers. Other preservation methods include lyophilisation and air-drying. In ophthalmology, amniotic membrane is increasingly used for ocular surface reconstruction, including the treatment of persistent epithelial defects and non-healing corneal ulcers, corneal perforations and descemetoceles, bullous keratopathy, as well as corneal disorders with associated limbal stem cell deficiency, pterygium, conjunctival reconstruction, corneoscleral melts and perforations, and glaucoma surgeries.

Amniotic membrane in ophthalmology: properties, preparation, storage and indications for grafting-a review.

Burns, non-healing wounds and pressure sores cause extensive damage to the skin leading to infection and loss of precious body fluids. Despite advances in burn management the mortality rate continues to be high and the search for an economical and easily available dressing to control burn wound infection continues. Autologous skin has limited availability and is associated with additional scarring. Conventional dressings require frequent changes which can be painful and may even require anaesthesia.

Evaluation of lyophilised, gamma-irradiated amnion as a biological dressing.

The purpose of the present study was to clinically and radiographically evaluate and compare the efficacy of demineralized freeze dried bone allograft (DFDBA) and bovine derived xenogenic bone graft (BDX) [Bio-Oss] with amniotic membrane (AM) as guided tissue regeneration (GTR) in the treatment of human periodontal Grade II buccal furcation defects. Ten patients suffering from chronic periodontitis, displaying bilateral Grade II buccal furcation defect, were randomly treated using DFDBA with AM (Experimental site A) or using bovine derived xenograft (BDX) with AM (Experimental site B). The clinical and radiographic parameters were recorded at baseline, 6 and 9 months. Healing was uneventful in all patients except one site which was treated with BDX + AM. At 9 months after therapy, soft tissue measurements for the DFDBA + AM group showed pocket depth (PD) reduction of 4.7 mm ± 0.58, and relative attachment level gain of 4.8 mm + 0.32, while the BDX + AM group showed a PD reduction of 4.4 mm ± 0.27, and AL gain of 5.1 mm ± 0.09. Osseous measurements showed bone fill of 2.1 mm ± 0.36 for the DFDBA + AM group and 2.43 mm ± 0.38 for the BDX + AM group. Percentage gain in bone was 76.3% for the DFDBA + AM group and 79.6% for the BDX + AM group. Statistical analysis revealed there was no statistical difference between the two materials in all measurements. Within the limits of the present study, it can be concluded that: (1) at 9 months after surgery both therapies resulted in significant PD reductions and CAL gains and (2) significant improvement was seen in bone fill and percentage gain with both the material, however, there was no significant difference between both.

A clinical and radiological evaluation of DFDBA with amniotic membrane versus bovine derived xenograft with amniotic membrane in human periodontal grade II furcation defects

The availability of safe and reliable, banked tissues in India has enabled the use of human bone allografts as a viable alternative to autografts in reconstructive surgery. Lyophilised, irradiated bone grafts were used in 2 cases of rhinoplasty, a case of hemifacial atrophy, and as a chin implant. In the patient with revision rhinoplasty the rib graft was resorbed. The patient with hemifacial atrophy developed seroma and infection in the zygomatic and infraorbital area and the rib graft had to be removed. The graft from the same rib that was placed over the mandible was retained well and incorporated completely. The iliac crest cortico-cancellous grafts did well in the second case of augmentation rhinoplasty and in the augmentation of chin. The primary objective of reconstructive surgery in the treatment of burns, non-healing wounds and pressure sores is to remove the dead tissue and restore the continuity of the skin without delay. Lyophilised, irradiated, human amnion is a temporary biological dressing conveniently available off-the-shelf. It was used in twenty four patients with burns, eight patients with bedsores and six patients with non-healing ulcers mainly on the foot. The total surface areas of burns sustained were from 2% to 40%. The burns ranged from second degree to deep third degree burns. Amnion was not used in patients with infected third degree burns. The amnion provided good biological cover in all the patients. It was easy to handle and apply, and provided pain relief. The duration of healing varied depending on the extent and depth of the wound and the amount of exudate. The superficial bedsores healed with a single application of amnion. Reduced exudate, healthy granulation tissue and enhanced epithelisation were observed following application of amnion.

Use of banked tissue in plastic surgery.

In India, the procurement of tissues for transplantation is governed by the Transplantation of Human Organs Act, 1994. However, although this law exists, it is primarily applied to organ transplantation and rules and regulations that are specific to tissue banking have yet to be developed.

Astrid Lobo Gajiwala

Papers

Evaluation of lyophilised, gamma-irradiated amnion as a biological dressing.

A clinical and radiological evaluation of DFDBA with amniotic membrane versus bovine derived xenograft with amniotic membrane in human periodontal grade II furcation defects

Use of banked tissue in plastic surgery.

Setting up a Tissue Bank in India: The Tata Memorial Hospital Experience.

Cross-correlative 3D micro-structural investigation of human bone processed into bone allografts.