The absence of basement membrane in overlapped acellular dermal matrix promotes tissue integration in implant-based breast reconstruction.

Abstract

In implant-based breast reconstruction (IBBR), acellular dermal matrix (ADM) is widely used for implant coverage and volume supplementation. Overlapping of ADMs often occurs, but the impact of the basement membrane (BM) on tissue integration in this context remains unclear. Therefore, this study aimed to histologically evaluate how BM presence affects long-term tissue integration in overlapped ADM constructs using a mouse model. Thirty-six rats were randomly assigned to three groups: single-layer ADM with BM facing the implant (G1), overlapped ADM with an intact BM between layers (G2), and overlapped ADM without BM between layers (G3). Silicone-ADM constructs were implanted subcutaneously, and histological analyses were performed at 3- and 6- months post-implantation to assess host cell infiltration, angiogenesis, immune response, and extracellular matrix (ECM) retention. At 6 months, G3 demonstrated significantly enhanced vessel formation and myofibroblast infiltration in both outer and inner ADM layers compared to G2. Immune cell infiltration (F4/80⁺ macrophages and CD3⁺ T cells) was also elevated in G3 at 3 months, but became comparable across groups by 6 months. ECM components, including collagen type I and elastin, were better preserved in the inner layer of G3, whereas G2 showed notable ECM degradation. In overlapped ADM constructs, removing the BM between layers enhances host cell infiltration and ECM retention, thereby supporting improved tissue integration. Although further clinical studies are warranted, these findings suggest that modifying BM involvement may help reduce complications and improve patient outcomes in IBBR. This study suggests that minimizing basement membrane involvement in overlapped ADM may enhance tissue integration, leading to improved long-term volume retention and patient satisfaction in implant-based breast reconstruction.