Human Amniotic Membrane and Amniotic Membrane–Derived Cells

Abstract

Human amniotic membrane (hAM) is the innermost layer of fetal membranes, which surrounds the developing fetus and forms the amniotic cavity. hAM and hAM-derived cells possess many properties that make them suitable for use in regenerative medicine, such as low immunogenicity, promotion of epithelization, anti-inflammatory properties, angiogenic and antiangiogenic properties, antifibrotic properties, antimicrobial properties, and anticancer properties. Many pathological conditions of the urinary tract lead to organ damage or complete loss of function. Consequently, the reconstruction or replacement of damaged organs is needed, which makes searching for new approaches in regenerative and reconstructive urology a necessity. The use of hAM for treating defects in kidneys, ureters, urinary bladder, and urethra was tested in vitro in cell cultures and in vivo in mice, rats, rabbits, cats, dogs, and also in humans. These studies confirmed the advantages and the potential of hAM for use in regenerative and reconstructive urology as stated above. However, they also pointed out a few concerns we have to take into consideration. These are (1) the lack of a standardized protocol in hAM preparation and storage, (2) the heterogeneity of hAM, and especially (3) low mechanical strength of hAM. Before any wider use of hAM for treating urological defects, the protocols for preparation and storage will need to be standardized, followed by more studies on larger animals and clinical trials, which will altogether extensively assess the potential of hAM use in urological patients.

Viable cryopreserved umbilical tissue (vCUT) reduces post-operative adhesions in a rabbit abdominal adhesion model

“…The low immunogenicity of placental tissues allows allogeneic use of placental grafts without matching between donors and recipients [ 46 , 47 ]. Cellular composition of placental membranes and umbilical tissue includes neonatal epithelial cells, fibroblasts and mesenchymal stem cells that are low immunogenic cells [ 14 , 48 ]. Lack of vasculature and nerves within placental membranes and umbilical tissue together with production of anti-inflammatory factors by endogenous placental cells contribute to placental membranes and umbilical tissue low immunogenicity [ 14 , 44 ].…”

Properties of viable lyopreserved amnion are equivalent to viable cryopreserved amnion with the convenience of ambient storage

“…In certain applications, when there are no reported differences in outcomes for viable and non-viable amnion the use of non-viable tissue conveniently stored at ambient temperatures is preferred. For example, previous studies have reported the use of non-viable cryopreserved or dehydrated amniotic membrane for ophthalmologic surgeries as well as for reconstructive urology procedures [ 50 , 51 ]. In addition, non-viable AM is used as a scaffold for cell culturing.…”

Human Amniotic Membrane Enriched with Urinary Bladder Fibroblasts Promote the Re-Epithelization of Urothelial Injury

“…Therefore, it is often used as a naturally derived biomaterial in tissue engineering and regenerative medicine. Its remarkable regenerative potential has also been demonstrated in the field of urology (reviewed in Ramuta and Kreft 7 ), where fresh or cryopreserved AMs were used as a graft for the reconstruction of the ureter 8 , bladder 9 , 10 , or urethra 11 . Although these studies showed the partially reconstructed urinary tract wall, they did not provide any data about the differentiation or functionality of the de novo established urothelia.…”