Stromal Cells Associated with Soft Tissue Augmentation by a Volume-Stable Collagen Matrix (VCMX) Are Predominated by Anti-inflammatory/Reparative Macrophages

This article defines immunophenotypes of stromal inflammatory and endothelial cells and fibroblasts 3 months after augmentation of the peri-implant soft tissue using a porcine cross-linked collagen matrix (VCMX). Peri-implant soft tissue samples were obtained from 12 patients at the lining mucosa (LM)–masticatory mucosa (MM) junction before (1) and 3 months after (2) augmentation. Immunohistochemical stains were performed to identify inflammatory cells (T [CD3] and B [CD20] lymphocytes, plasma cells [CD138]), macrophages (CD68-proinflammatory, CD163-anti-inflammatory/ reparative), endothelial cells (CD31, CD34), and fibroblasts (CD90, TE-7). Differences in the mean positively stained cells pre- and postaugmentation were analyzed by Wilcoxon signed-rank test. CD31+ endothelial cells showed increased mean numbers in MM2 compared to MM1 (P = .025) and in LM2 compared to LM1 (P = .047). CD163+ anti-inflammatory macrophages showed higher mean numbers in MM2 than in MM1 (P = .021) and in LM2 than in LM1 (P = .012). All other cell phenotypes showed nonsignificant changes between pre- and postaugmentation. This molecular study provides novel insight on the frequency of stromal cell phenotypes in the wound healing process at 3 months postaugmentation with VCMX, with anti-inflammatory CD163+ macrophages being predominant. This should be further investigated to help find novel therapeutic approaches to modulate and promote the VCMX-related healing process.