Collagen synthesis: Collagens, which are synthesised by fibroblasts, provide strength and integrity for all tissues in the body and therefore play a particularly vital role in wound repair. Collagens are a key component of all phases of wound healing. Immediately after injury, exposed collagen comes into contact with blood, promoting platelet aggregation and activating chemotactic factors involved in the response to injury. Later collagen becomes the foundation of the wound ECM. Invading fibroblasts synthesise and secrete types I and III collagen to form the new matrix.
Angiogenesis: The process of forming new blood vessels occurs concurrently during all stages of the healing process. TGF-β and PDGF, secreted by the platelets during the haemostatic …show more content…
Each 'granule' contains a loop of capillaries and therefore bleeds easily if traumatised. Granulation tissue is made up mainly of proliferating fibroblasts, capillaries and tissue macrophages in a matrix of collagen, glycosaminoglycans (GAGs) including HA, and the glycoproteins fibronectin and tenascin [13], [14]. Granulation tissue formation is evident as early as 48 hours after wounding and by 96 hours fibroblasts become the predominant cell type in this tissue …show more content…
Wound remodelling occurs when the underlying contractile connective tissue shrinks in size to bring the wound margins closer together. Contraction occurs through the interactions between fibroblasts and the surrounding ECM. These interactions may be influenced by a number of extracellular factors including TGF-β, PDGF and FGF [10]. With time the density of macrophages and fibroblasts is reduced by apoptosis triggered by unknown sources [20]. However, it has been suggested that apoptosis may be signalled by the withdrawal of cytokines as the wound heals, although many other theories exist including myofibroblast differentiation itself signalling apoptosis and the release of certain factors following re-epithelialisation [21]. With continued remodelling the outgrowth of capillaries is halted, blood flow to the area is reduced and metabolic activity in the area declines. An acellular, avascular scar is the final result of an acute wound healing
Angiogenesis: The process of forming new blood vessels occurs concurrently during all stages of the healing process. TGF-β and PDGF, secreted by the platelets during the haemostatic …show more content…
Each 'granule' contains a loop of capillaries and therefore bleeds easily if traumatised. Granulation tissue is made up mainly of proliferating fibroblasts, capillaries and tissue macrophages in a matrix of collagen, glycosaminoglycans (GAGs) including HA, and the glycoproteins fibronectin and tenascin [13], [14]. Granulation tissue formation is evident as early as 48 hours after wounding and by 96 hours fibroblasts become the predominant cell type in this tissue …show more content…
Wound remodelling occurs when the underlying contractile connective tissue shrinks in size to bring the wound margins closer together. Contraction occurs through the interactions between fibroblasts and the surrounding ECM. These interactions may be influenced by a number of extracellular factors including TGF-β, PDGF and FGF [10]. With time the density of macrophages and fibroblasts is reduced by apoptosis triggered by unknown sources [20]. However, it has been suggested that apoptosis may be signalled by the withdrawal of cytokines as the wound heals, although many other theories exist including myofibroblast differentiation itself signalling apoptosis and the release of certain factors following re-epithelialisation [21]. With continued remodelling the outgrowth of capillaries is halted, blood flow to the area is reduced and metabolic activity in the area declines. An acellular, avascular scar is the final result of an acute wound healing