Fibroblast responses to exogenous and autocrine growth factors relevant to tissue repair - The effect of aging

The aging process is often associated with impaired mound healing, but the cellular and molecular mechanisms implicated are not completely understood. Accordingly, we have investigated the response of human fibroblasts from donors of various ages to platelet derived and autocrine growth factors, in terms of mitogenicity as well as extracellular matrix synthesis and degradation. Our data indicate that fibroblast responses persist during aging, suggesting the involvement of systemic factors in the regulation of the healing process. In this context, we have found that neutral endopeptidase-24.11, a metalloproteinase controlling the action of neuroendocrine peptides and also of immunocyte chemotaxis, is overexpressed during aging. Finally, the connection between these data and those from in vitro aging studies is discussed.