FIBROBLAST RESPONSES TO CYTOKINES ARE MAINTAINED DURING AGING

Impaired wound healing in older individuals may result from a global d eficit of fibroblast activity or a decreased response of aged fibrobla sts to stimulation by inflammatory cytokines. Twenty-eight fibroblast cell strains were developed from normal human skin aged 3 days to 84 y ears. Mitogenic response to cytokines, epidermal growth factor, tumor necrosis factor-alpha, platelet-derived growth factor or fetal bovine serum was determined using a 4-hour H-3-thymidine incorporation assay. Synthesis of collagen and noncollagen proteins was determined basally and in response to transforming growth factor-beta using a 6-hour H-3 -proline incorporation assay. Neither the mitogenic response to cytoki ne stimulation (p > 0.3) nor the synthesis of collagen and noncollagen protein after transforming growth factor-beta stimulation (p > 0.4) v aried with the age of the cell donor. Individual cell lines' response to cytokine stimulation varied widely, reflecting differences commonly seen in patients' wound-healing abilities. Cellular responses to woun d-healing cytokines are preserved as people age. Abnormalities in woun d healing in older patients may be the result of altered immune initia tion of healing or the cumulative result of concomitant disease.