PREADIPOCYTE FUNCTION AND AGING - LINKS BETWEEN AGE-RELATED-CHANGES IN CELL-DYNAMICS AND ALTERED FAT TISSUE FUNCTION

OBJECTIVE: To review recent findings about changes with age in the rep lication and differentiation of preadipocytes, the progenitor cells in fat tissue that are capable of differentiating into fat cells, and to examine possible links between these alterations and age-related chan ges in fat tissue function. DESIGN: A survey and analysis of recent li terature concerning changes in preadipocyte and fat cell function with age. CONCLUSIONS: Intrinsic aging changes in fat cells and preadipocy tes as well as in factors extrinsic to fat tissue (such as food intake and absorption and hormonal status) contribute to age-related alterat ions in fat tissue function and cellularity. Changes with age in pread ipocyte number, replicative potential, and capacity for differentiatio n, which may be linked to aging changes in fat cell size, number, and function, have been identified. The decline in preadipocyte capacity f or differentiation and the associated decline in fat cell lipogenic ca pacity may be particularly important in contributing to the decrease i n fat mass and alterations in fat tissue function that occur between m iddle- and old age. These declines result from blunting of the changes in gene expression that occur during preadipocyte differentiation and map, in turn, be related to altered regulation of particular transcri ption factors that control the preadipocyte differentiation program an d maintenance of fat cell function.