Porcine Acellular Dermal Matrix Increases Fat Survival Rate after Fat Grafting in Nude Mice

Autologous fat grafts have been widely in use for reconstruction, contour abnormalities, and cosmetic surgeries. However, the grafted fat one-year survival rate is unpredictable and always low (20%–80%). Standardizing the existing transplantation technology is difficult due to the limiting conditions. Scaffold materials or drugs are unsuitable to employ because of legal restrictions, complex production, and undetermined hazards. Therefore, a simpler and more effective approach to improve grafted fat survival rate is using commercial products as additives. Earlier studies proved that porcine acellular dermal matrix (PADM), a biomaterial clinically used for wound repair, could work as a scaffold for lipo-implantation. This study aimed at investigating the hitherto unclear effect of PADM on transplanted fat survival.

Thirty-two 8-week-old female nude mice were divided into two groups. Control mice received a 300 μl fat injection, while the PADM group mice were injected with a 300 μl PADM-fat mixture. After a 4-week treatment, fat weight and liquefaction ratio were assessed. Histological changes were quantified via hematoxylin & eosin (H&E) staining. Macrophage infiltration and vascular regeneration were revealed using an anti-CD34 antibody. Mouse and human mRNA expression levels were gauged via RNA-sequencing. On the third day post implantation, the mRNA expression levels of inflammatory genes Mcp-1 and Tnf-α were measured by qRT-PCR.

The weight of surviving grafted fat did not differ between the control and the PADM group. However, adding PADM significantly decreased fat liquefaction. H&E-stained sections showed that PADM decreased fat necrosis, increased fat tissue regeneration, and raised CD34 levels in the regenerated tissue. RNA-sequencing showed that, compared to controls, fats from PADM-added group expressed more mouse-related mRNA but less human-related mRNA. The following GO and KEGG analysis showed that added PADM increased extracellular matrix (ECM) genes expression levels. The qRT-PCR showed that adding PADM increased Mcp-1 and Tnf-α mRNA expression levels.

In summary, PADM addition increased fat survival rate by reducing fat liquefaction through an increased macrophage infiltration, ECM regeneration, and revascularization. Therefore, PADM addition is a workable application in autologous fat grafting.

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