ABSTRACT
During wound healing, transition from inflammatory to granulation phase is mediated by a variety of growth factors and cytokines including PDGF, TGF-α , TGF-β , FGFs, IGF-1, CSF, ILs, and TNF-α (10) . These growth factors and cytokines are derived from macrophages, epidermal keratinocytes, and fibroblasts. Multiple metabolic pathways lead to the formation of new collagen and repair of extracellular matrix during the granulation phase. The final stage of wound healing after granulation and wound re-epithelialization or peeling of sunburned skin is the beginning of dermal tissue remodeling. During this stage, low strength, unorganized type 3 collagen and elastin structures produced during the ECM production phase are replaced by stronger type 1 collagen and structured elastin fibers to provide strength and resiliency to the dermis. This remodeling phase can last for several months and is the key to reversing the visible effects of skin aging (11) .
