Fibroblast Lineage Switching as the Developmental Origin of Scarring and Target for Regenerative Healing

The document examines fibroblast lineage switching as a key factor in scarring versus regenerative healing, highlighting differences between fetal and adult wound healing. Fetal wounds heal without scarring due to pro-regenerative fibroblasts (ENFs) and minimal inflammation, while adult wounds involve pro-fibrotic fibroblasts (EPFs), leading to scarring. The study emphasizes the role of the extracellular matrix (ECM) and cytokine profiles in these processes, with fetal ECM rich in collagen types III and V and higher levels of anti-inflammatory cytokines. It also explores the integrin–focal adhesion kinase (FAK) pathway's impact on fibrotic outcomes and fibroblast heterogeneity, noting that papillary fibroblasts promote regeneration, whereas reticular fibroblasts lead to scarring. The research suggests that mimicking fetal wound environments and targeting fibroblast behavior could enable regenerative healing in adults, offering new therapeutic strategies for scarless tissue repair.