Remodelling Phase (Wound Healing)
The final wound healing phase (weeks to years) where new tissue matures and strengthens. Type III collagen is progressively replaced by type I collagen, and the tissue gradually approaches (but may never fully match) the strength of the original. Matrix metalloproteinases regulate this process.
Technical Context
Remodelling involves coordinated collagen synthesis, degradation, and reorganisation. Collagenases (MMP-1, MMP-8, MMP-13) cleave intact collagen, while gelatinases (MMP-2, MMP-9) degrade the resulting fragments. The MMP/TIMP balance determines net collagen turnover. Type III collagen (predominant in granulation tissue) is progressively replaced by type I collagen (organised along mechanical stress lines through mechano-transduction by fibroblasts). Wound tensile strength increases from approximately 3% of normal at 1 week to 20% at 3 weeks to maximum 70-80% at 12+ months — wounds never fully regain original tissue strength. Hypertrophic scars result from excessive collagen deposition (elevated TGF-β, reduced MMP activity), while keloids represent pathological scarring that extends beyond original wound boundaries. Understanding remodelling biology is relevant to evaluating peptides claimed to improve scar quality or accelerate tissue maturation.