Write a 4 page essay on Evaluate the proposition that the research findings from the use of animal models has led to new approaches to reduce the effects of ageing in wound healing.
This might help to identify the targets for novel and effective drug therapy. Normal wound healing is innate host immune response for tissue regeneration and repair involving coagulation, inflammation, epithelialization, formation of granulation tissue and tissue remodeling (Ashcroft et al. 2002). In response to injury stages of wound healing are depicted in figure 1 (Gosain and DiPietro 2004).
The number of polypeptide growth factors and cytokines like epidermal growth factor (EGF), basic fibroblast growth factor (?-FGF), platelet derived growth factor (PDGF) A & B isoforms, the transforming growth factor (TGF-?), vascular endothelial growth factor (VEGF) plays an important role in wound healing process.
It is demonstrated that delayed wound healing in both elderly animal and human individuals is due to decreased inflammatory and proliferative responses, delayed angiogenesis, delayed remodeling and slower reepithelialization (Strigini and Ryan, 1996). Morphology of skin changes with aging process. It involves flattening of the dermo-epidermal junction, disorganized microcirculation, decrease in number of cells as well as dermal cell constituents like fibroblasts, mast cells, macrophages. Also, the morphology, properties and quantity of dermal extracellular matrix content such as collagen, elastin, glucosaminoglycans changes with aging. These variations lead to delayed cellular proliferation, migration, modified binding of growth factor to matrix, alteration in adhesion molecule synthesis and changes in molecular signaling (Ashcroft et al. 2002). These changes affect functional cell response to all the stimuli. The age-related changes in the individual phases of healing are summarized in Table 1 (Goain and DiPietro 2004).
The animal models which are used to study the impact of aging on wound healing are not suitably characterized. Therefore the reported evidences itself are contradictory (Ashcroft et al., 1995). Only well