Telomeres and Ageing
Cell senescence is linked to telomere length. When telomeres are too short the cell dies. But could the process be reversed? Prevent telomere shortening or increase telomere length and you have an eternal cell, and hey presto! we get to live forever. Some scientists are giving serious thought to this, and a small handful believe it may one day be possible; either by gene therapy or by activating telomerase, the enzyme that maintains telomere length, and minimises the amount that is lost during cell division.
However, this has not been observed in humans, though the relationship between lengthy telomeres and longer life spans has been demonstrated in the roundworm C. elegans. A team of researchers writing in Nature Genetics in 2004 reported that worms with longer telomeres lived on average 20 per cent longer than normal worms.
But there could be a price to pay if we tinker with telomere length - cancer. Cancerous cells can continue to divide indefinitely by maintaining telomere length. The enzyme telomerase is not active in most differentiated cells, however, it is active in stem cells, germ cells, and tumour cells, and adds bases to telomeres. Lengthening these structures could promote tumour genesis and prevent malfunctioning cells from dying. Perhaps nature prefers us to shuffle off this mortal coil when we reach our natural sell-by date.
Although it seems highly unlikely that immortality will ever be achieved, telomeres could possibly be manipulated by drugs or gene therapy to minimise the effects of ageing and to increase lifespans by several years.