Preparation of human amniotic membrane for transplantation in different application areas

Abstract

The human amniotic membrane (hAM) is the inner layer of the placenta and plays protective and nutritional roles for the fetus during pregnancy. It contains multiple growth factors and proteins that mediate unique regenerative properties and enhance wound healing in tissue regeneration. Due to these characteristics hAM has been successfully utilized in ophthalmology for many decades. This material has also found application in a variety of additional therapeutic areas. Particularly noteworthy are the extraordinary effects in the healing of chronic wounds and in the treatment of burns. But hAM has also been used successfully in gynecology, oral medicine, and plastic surgery and as a scaffold for in vitro cell culture approaches. This review aims to summarize the different graft preparation, preservation and storage techniques that are used and to present advantages and disadvantages of these methods. It shows the characteristics of the hAM according to the processing and storage methods used. The paper provides an overview of the currently mainly used application areas and raises new application possibilities. In addition, further preparation types like extracts, homogenates, and the resulting treatment alternatives are described.

PURION® processed human amnion chorion membrane allografts retain material and biological properties supportive of soft tissue repair

“…However, it is also critical to understand the impact of processing techniques on the biomolecules embedded within the allografts. 20 A multiplex ELISA detected the proteins contained within LHACM and identified a variety of growth factors and cytokines that regulate vital processes in wound healing including cell migration, proliferation, inflammation, angiogenesis and ECM remodeling. 38 Similar factors have previously been identified in DHACM, a dehydrated amniotic membrane allograft.…”

“…In order to provide the most beneficial and safe amniotic membrane allograft for therapeutic purposes it is necessary to utilize the best methods for collection, processing and storage while preserving the native structure of the amniotic tissue. 20 Extensive analysis of PURION ® processed amniotic membrane allografts has demonstrated that this processing method retains well-known regulatory proteins and preserves the bioactivity to stimulate cellular activities supportive of wound healing. Indeed, increases in proliferation and migration of multiple cell types including stem cells, HDFs, tenocytes, and endothelial cells highlights the ability of amniotic membrane allografts to impact basic cellular functions.…”

“…15,18,19 The clinical success of amniotic membrane allografts is related to the processing techniques that preserve the membrane properties, including the biophysical structure and bioactivity, while making them safe and readily accessible for the provider. 9,20 This study looks to evaluate two unique PURION ® processed amniotic tissue allografts to characterize the material properties and the biological activities that are therapeutically relevant to wound healing. Lyophilized human amnion, intermediate layer, and chorion membrane (LHACM) is a freeze-dried tri-layer allograft; whereas, dehydrated human amnion, chorion membrane (DHACM) is an air-dried bi-layer allograft.…”

Dehydrated human amnion/chorion membrane allograft with spongy layer to significantly improve the outcome of chronic non‐healing wounds

“…Among these, dehydrated amnion/chorion membranes (dHACMs) are the most widely utilised for the promotion of wound healing. However, the specific structure and composition of dHACMs, including the presence of amnion or chorion only, or both, along with various matrix components, growth factors and cytokines, depend on the processing methods employed 16–22 . Generally, the amnion and chorion from donated human placentas are isolated through a cleansing proprietary process and either processed separately or laminated to form a two‐layer graft, before being dehydrated under controlled drying conditions 23 .…”

“…However, the specific structure and composition of dHACMs, including the presence of amnion or chorion only, or both, along with various matrix components, growth factors and cytokines, depend on the processing methods employed. [16][17][18][19][20][21][22] Generally, the amnion and chorion from donated human placentas are isolated through a cleansing proprietary process and either processed separately or laminated to form a two-layer graft, before being dehydrated under controlled drying conditions. 23 All of the dHACMs that have been utilised in clinical trials to date lack the spongy layer, which bridges the amnion and chorion sides and, thus, is also referred to as an intermediate layer.…”