Scar Tissue (Fibrosis)
Dense, fibrous tissue that replaces normal tissue after injury. Scar tissue is primarily composed of type I collagen arranged in a disorganised pattern, making it less functional than the original tissue. Reducing scar formation and promoting regenerative healing is a goal of tissue repair research.
Technical Context
Scar tissue differs from normal tissue in: collagen organisation (parallel, densely packed fibres rather than basket-weave pattern of normal skin), collagen composition (initially type III, transitioning to type I but with different crosslinking patterns), absence of skin appendages (no hair follicles, sweat glands, or sebaceous glands in mature scar), reduced elasticity (less elastin), altered vascularity (initial hypervascularisation followed by regression), and reduced tensile strength (70-80% of normal maximum). Pathological scarring: hypertrophic scars (raised, red, confined to wound boundaries — regress over 1-2 years) and keloids (raised, extending beyond wound boundaries, do not spontaneously regress — genetically predisposed, more common in darker skin types). Anti-fibrotic/anti-scarring peptide research aims to modulate TGF-β signalling, MMP/TIMP balance, or myofibroblast apoptosis to promote regenerative rather than fibrotic healing.