Anti aging guide

Age-related cellular changes



Various changes have been described in aging cells, such as a variation in the number of chromosomes (aneuploidy) and the accumulation of inert waste material or ‘clinker’ in the form of a `wear and tear’ pigment called lipofuscin in nerve, kidney, liver, and muscle cells where it interferes with energy release and affects function.

Animal tissue transplantation experiments have shown that some tissues can be transplanted time and again and so outlive not only the original donor but also a series of recipients. In vitro studies have yielded even more striking and informative results. Certain human cell lines can be cultured in perpetuity, but only if they are abnormal (cancerous). In the 1960s and 1970s, Hayflick, worked with normal human embryonic fibroblasts, the relatively simple cells that produce the fibrous skeleton of our connective tissue. He showed that there seemed to be a fixed limit to the number of divisions that these cells were capable of, although there was a fair amount of individual variation. The upper limit was 50, give or take ten either way, but if the cells were taken from mature subjects the capacity for reduplication was reduced, although to an extent correlating poorly with the age of the donor. Cells frozen in liquid nitrogen for over 20 years apparently retain a ‘memory’ of the number of divisions they are still due to undergo following reconstitution. Towards the limit of their potential span, these fibroblasts acquire certain attributes shared by aging and malignant cells, such as aneuploidy. Hayflick’s work points convincingly towards the existence of a biological clock which ticks by at a certain pre-ordained rate.

Posted by Carol Hudgens - April 19, 2012 at 4:18 pm