Clinical Evaluation of an Off-the-Shelf Allogeneic Adipose Matrix for Soft Tissue Reconstruction

Autologous fat grafting is an established technique for addressing volume and contour abnormalities in plastic surgery, with substantial utility in both aesthetic and reconstructive procedures.1–7 However, fat grafting may not always be possible when lack of donor site precludes adipose harvest or when the volume of material required does not balance associated costs of an additional outpatient surgical procedure. Further, complications of fat grafting, including poor adipocyte survival under hypoxia, cell lysis, oil accumulation, and formation of oil cysts and calcifications, can limit efficacy. There is a significant clinical interest in developing an alternative, off-the-shelf product that eliminates the need for tissue harvesting and graft processing, overcomes fat grafting associated complications, and can be delivered outside of an operating room setting. Extracellular matrix (ECM) scaffolds are commercially available for a wide variety of clinical applications and are useful for tissue regeneration and wound healing. Adipose tissue is an abundant source of cell-adhesive matrix proteins such as collagens, fibronectin, and laminin and when extracted, yield a biomaterial with favorable tissue regenerative properties. Preclinical studies by Kokai et al and Giatsidis et al have evaluated the safety and efficacy of allograft adipose matrix (AAM) processed by MTF Biologics (Edison, NJ), demonstrating the ability of the material to form new adipose tissue in immunocompromised and immunocompetent mouse models, respectively.8,9 Clinically, AAM safety has been assessed following implantation into the dorsum of the nondominant wrist in healthy human subjects and histologic analysis supported previous results in animal studies for matrix reorganization and adipose generation.8 Herein, we report the results of a randomized prospective clinical study conducted at the University of Pittsburgh where AAM (Renuva; MTF Biologics) was grafted into the pannus of presurgical abdominoplasty patients with longitudinal biopsies obtained to assess the cellular response. Renuva is regulated by the Food and Drug Administration and classified as a human cellular and tissue-based product. The primary objective of the study was to evaluate local tissue reaction, tissue architecture, and AAM remodeling after injecting into the subcutaneous tissues of the abdominal wall in subjects undergoing elective abdominoplasty surgery. The secondary objective was to assess the rate of complications of the AAM in human subjects undergoing elective abdominoplasty. This is the first such clinical study showing that AAM promotes soft tissue regeneration in an allograft setting and is a promising scaffold for regenerating adipose tissue.