Laboratory Research
Placental tissues have been utilized to treat a variety of wounds. Various processing methods have been used, including cryopreservation, dehydration, lyophilization, and hypothermic storage. Processing methods have been shown to impact tissue characteristics, including extracellular matrix (ECM) structure, graft thickness, and degradation characteristics. In this study, we evaluated the impact of a fresh hypothermic storage process (AlloFresh™) on both an amnion product (HSAMº) and a chorion product (HSCM†) and compared them to unprocessed and dehydrated placental tissues. We evaluated qualitative structural differences, quantified tissue thickness, and measured degradation characteristics using an in vitro wound model utilizing stimulated wound fluid (SWF).
Methods:
Placental tissue from at least two donors were prepared as 1) unprocessed placental membranes, 2) processed into HSAM or HSCM, or 3) processed into dehydrated membranes. Of note, HSCM processing includes a debridement step, which removes portion of the trophoblast membrane. Qualitative structural assessments for membranes were made using hematoxylin and eosin and Masson’s trichrome staining. To quantify differences in graft thickness, multiple areas were sampled and quantified using ImageJ. In vitro degradation characteristics were measured following membrane exposure to SWF for up to 7 days at 37°C. Evaluation included measuring collagen in solution and taking dry weights of samples.
Results:
HSAM maintained intact epithelial and stromal layers, while HSCM retained intact reticular, basement membrane, and partial trophoblast layers. Quantification showed native amnion grafts and HSAM resulted in comparable graft thickness. As expected, HSCM tissue thickness was reduced compared to native chorion, but all retained layers were comparable. Fresh and HSAM/HSCM membranes were substantially thicker than dehydrated membranes. In vitro, HSAM and HSCM both degraded in SWF; however, both grafts remained present after 7 days. Additionally, the increased thickness of HSCM compared to HSAM resulted in approximately 4x greater product remaining after 7 days, highlighting the increased durability of HSCM.
Discussion:
These results demonstrate that HSAM and HSCM both retain native tissue characteristics, including architectural structure and thickness, found in fresh, unprocessed amnion and chorion membranes. These results highlight the durability of HSAM and HSCM observed in an in vitro model with SWF.
Trademarked Items: º Affinity®, Organogenesis, Canton, MA
† Novachor®, Organogenesis, Canton, MA
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