Human Amniotic Membrane for the Treatment of Cryptoglandular Anal Fistulas

Background: Implantation of the amniotic membrane and their derivatives can have a beneficial effect on tissue repair and regeneration. We report for the first time the implant of an amniotic membrane in a patient affected by cryptoglandular anal fistula. Methods: A patch of human amniotic membrane was implanted in a female patient affected by an anterior transphincteric fistula. Following an accurate curettage of the anal fistula, the cryopreserved amniotic membrane was thawed and then washed in the operating room; one side of the membrane was transfixed with a resorbable suture thus creating an implantable fusiform patch. The membrane was subsequently implanted into the fistula tract from the external to the internal opening. The inner and outer parts of the membrane were then sutured to the internal and external fistula openings. Results: No intraoperative or postoperative complications occurred. The patient was discharged one day after the procedure after an uneventful hospitalization. At the 1-week, 1- and 3-month follow-up visits no pain (VAS 0) was referred by the patient and no inflammation was evident at the level of the previous external fistula opening. Conclusions: The implant of human amniotic membrane in a patient affected by cryptoglandular anal fistula was safely and easily performed. Moreover, future studies to assess the efficacy in the long-term follow-up are needed.

Human amniotic mesenchymal stromal cells support the ex vivo expansion of cord blood hematopoietic stem cells

Currently, more than 30 000 allogeneic hematopoietic stem cell (HSC) transplantations have been performed for the treatment of hematological and nonhematological diseases using HSC from umbilical cord blood (CB). However, the wide utilization of CB as a source of HSC is limited by the low number of cells recovered. One strategy to expand ex vivo CB‐HSC is represented by the use of bone marrow mesenchymal stromal cells (BM‐MSCs) as a feeder to enhance HSC proliferation while maintaining HSC stemness. Indeed, BM‐MSCs have been recognized as one of the most relevant players in the HSC niche. Thus, it has been hypothesized that they can support the ex vivo expansion of HSC by mimicking the physiological microenvironment present in the hematopoietic niche. Due to the role of placenta in supporting fetal hematopoiesis, MSC derived from the amniotic membrane (hAMSC) of human term placenta could represent an interesting alternative to BM‐MSC as a feeder layer to enhance the proliferation and maintain HSC stemness. Therefore, in this study we investigated if hAMSC could support the ex vivo expansion of HSC and progenitor cells. The capacity of hAMSCs to support the ex vivo expansion of CB‐HSC was evaluated in comparison to the control condition represented by the CB‐CD34⁺ cells without a feeder layer. The coculture was performed at two different CD34⁺:MSC ratios (1:2 and 1:8) in both cell‐to‐cell contact and transwell setting. After 7 days, the cells were collected and analyzed for phenotype and functionality. Our results suggest that hAMSCs represent a valuable alternative to BM‐MSC to support: (a) the ex vivo expansion of CB‐HSC in both contact and transwell systems, (b) the colony forming unit ability, and (c) long‐term culture initiating cells ability. Overall, these findings may contribute to address the unmet need of high HSC content in CB units available for transplantation.