Ups and downs of aging studies in vitro: the crooked path of science

Different approaches using cell culture techniques to study the biology of aging are critically described. Most of the studies concerned the relationship between cell division potential and aging. The growth potential of cells is fundamental for aging of the organism, since it relates to phenomena such as the regeneration of tissues, wound healing, the immune response, and stem cell renewal. Unfortunately many experiments were misinterpreted disregarding the physiology of the mammalian organism. The terminal postmitotic cell, on which most research has been concentrated, seems irrelevant for aging of the organism. Nevertheless, some experiments yielded important contributions to the understanding of the biology of cell division. Future research should ascertain such interesting suggestions as the terminal differentiation hypothesis of the human fibroblast life cycle. It is important to elucidate the significance of the increased number of postmitotic cells in pathological processes. A neglected area should be further explored: the relationships between structural modifications of the cell, decreased probability of activating energy barriers, and decline of the division potential.