Distribution of amniotic stem cells in human term amnion membrane

Amnion membrane studies related to miscarriage have been conducted in the field of obstetrics and gynecology. However, the distribution of stem cells within the amnion and the differences in the properties of each type of stem cells are still not well understood. We address this gap in knowledge in the present study where we morphologically classified the amnion membrane, and we clarified the distribution of stem cells here to identify functionally different amniotic membrane–derived stem cells. The amnion can be divided into a site that is continuous with the umbilical cord (region A), a site that adheres to the placenta (region B), and a site that is located opposite the placenta (region C). We found that human amnion epithelial stem cells (HAECs) that strongly express stem cell markers were abundant in area A. HAEC not only expressesed stem cell-specific surface markers TRA-1-60, Tra-1-81, SSEA4, SSEA3, but was also OCT-3/4 positive and had alkaline phosphatase activity. Human amniotic mesenchymal stem cells expressed KLF-A, OCTA, Oct3/4, c-MYC and Sox2 which is transcription factor. Especially, in regions A and B they have expressed CD73, and the higher expression of BCRP which is drug excretion transporter protein than the other parts. These data suggest that different types of stem cells may have existed in different area. The understanding the relation with characteristics of the stem cells in each area and function would allow for the efficient harvest of suitable HAE and HAM stem cells as using tool for regenerative medicine.

A Combination of Coconut Fiber Suture and Tamarind Seed Gel with Dehydrated Human Amnion Membrane for Wound Surgery in Rats

Today, there are over 2,000 different biomaterials used for various medical applications, but none of these biomaterials are 100% compatible with all human beings. Coconut fiber is widely available but has not been tested as a safe natural alternative for sutures. Immature coconut fiber is nonabsorbable and is effective for cuts and open wounds when used in combination with dehydrated human amnion membrane (dHAM). Immature coconut fiber, tamarind seed polysaccharide (TSP), and dHAM were prepared to test their combinational effect on wound healing in rats. TSP enhanced cell viability, proliferation, and migration in human skin cells and cured wounds both individually and in combination with dHAM. An antibiotic-free combination of the human amniotic membrane with intact epithelium, tamarind seed polysaccharide, and immature coconut fiber provided faster wound healing. Significantly higher wound healing was seen on the 11th day based on an initial 10 mm biopsy punch surgery in Wistar rats compared to control groups. Histological studies revealed thickened dermis edges with more neutrophil infiltration. Collagen deposition in the dermis was homogeneous across the excised skin tissue in the test group, again attesting to the utility of this procedure. This research signifies the use of TSP gel together with the amnion membrane representing a “smart patch” with wound healing potential, which would encourage further research on the smart patch made using a combination of plant and animal biological materials.

Anterior Segment Surgeries Performed During the Lockdown Period of the COVID-19 Pandemic

Purpose: This study aimed to evaluate the anterior segment surgeries performed in the coronavirus (COVID-19) lockdown period when prevention is at the forefront, in terms of etiology, referral region, demographic characteristics, and surgeries performed.Methods: A total of 144 cases who underwent anterior segment surgeries between 19 March 2020 and1 June 2020 were retrospectively reviewed from archive files. The demographic data and ophthalmological examinations of the patients, the region they were referred from, and the surgeries performed were noted.Results: A total of 144 patients, 49 women (34%) and 95 men (66%), were included in this study. The mean age of the patients was 31.30±25.88 (1-86) years. The presenting complaint was in the right eye in 43.7% of the cases, in the left eye in 52.8%, and in both eyes in 3.5% of the cases. While 94.4% of all cases applied from Istanbul, the remaining 5.6% applied from outside the province. Whereas 43.7% of the cases consisted of patients we had followed up previously, 56.3% presented to our hospital for the first time. Our hospital was the first referenced center in only 39.6% of the cases. When evaluated in terms of etiology, corneal perforation (18.1%) was the most common, followed by keratitis (13.2%). The most common surgical intervention was amnion membrane transplantation (19.4%), followed by perforation repair (16.7%).Conclusion: Ophthalmologic surgeries are continuing during the ongoing COVID-19 intervention process. Special algorithms are required to reduce the risk of transmission in terms of COVID-19 and to ensure continuity of health care for ophthalmology patients.

The Influence of the Preservation Method and Gamma Irradiation Sterilization on TGF-β and bFGF Levels in Freeze-Dried Amnion Membrane (FD-AM) and Amnion Sponge

Background. Amnion grafts can be preserved as freeze-dried amnion membrane (FD-AM) and amnion sponge. Preserved grafts require to be sterilized by gamma irradiation. However, each step of the process could affect its biological properties. Even so, there are only a few studies that report the influence of the preservation method and gamma irradiation on growth factor levels in preserved amniotic grafts. Methods. This was an in vitro experimental study with a pretest-posttest group design using a consecutive sampling technique in one batch of amnion donors at a particular time. The amnion was made into FD-AM and amnion sponge preparations, and they were sterilized with gamma irradiation (15 kGy and 25 kGy). Nonirradiated specimens served as controls, and 20 mg of each specimen was pulverized to evaluate the growth factors levels using ELISA. Results. There were significant decreases in amnion sponge compared to the FD-AM, both in transforming growth factor beta (TGF-β) and basic fibroblast growth factor (bFGF) levels and in the preirradiated and 25 kGy postirradiated preparations ( p ≤ 0.05 ). The growth factor levels in the preirradiated and postirradiated FD-AM (both 15 kGy and 25 kGy) showed significant differences ( p ≤ 0.05 ). Likewise, the preirradiated amnion sponge group’s growth factor levels compared with the postirradiated amnion sponge group also showed a significant decrease ( p ≤ 0.05 ). Conclusion. TGF-β and bFGF levels were lower in amnion sponge than FD-AM. The FD-AM and amnion sponge preparations’ growth factors levels were reduced following gamma irradiation sterilization. Although the decrease in growth factor levels is significant, the number of growth factor levels is still sufficient for tissue healing.