Early-Aging Disease Offers Clues to Normal Aging

Progeria is a disease that causes children to experience symptoms normally connected with advanced old age, such as hardening of the arteries, joint stiffness, hair loss, and skeletal deformities. Children with the condition typically die in their teens, usually from cardiovascular problems. While this accelerated-aging disease is extremely rare, scientists have recently discovered a connection between the protein mutation that causes progeria and the mechanisms of the normal aging process in most of us.

Healthy people have a protein in their cells called lamin A. Children with progeria have a mutated version of lamin A called progerin. This toxic protein is responsible for the rapid aging and inevitable early death of progeria patients. But new research conducted at the National Institutes of Health reveals that normal people also produce small amounts of progerin.

In most people, the aging process is reflected in the telomeres, small DNA "caps" that are found on each end of a chromosome. They've been likened to aglets, the little plastic tips on the ends of shoelaces. Each time a cell divides, its telomeres are shortened and progerin is produced, damaging the cell. The shorter the telomeres become, the more progerin is created. Eventually, the cell can no longer divide and it dies. This is the process by which most of us age. In fact, scientists have found that the shorter the telomeres, the greater the likelihood of dying. Conversely, someone with long telomeres has a good chance of having a long life.

Scientists do not know exactly what "flips the switch" and causes telomeres to release progerin. However, that shouldn't stop anyone from trying to keep his or her telomeres as long as possible. There is evidence that diet, exercise, and body composition may play a part in telomere length. One study found a modest connection between longer telomeres in women and a high-fiber diet. It also found that women with smaller waists had longer telomeres. Another study showed that even brief periods of vigorous physical exercise prevent telomere shortening.

We may not be able to stop our aging. But with the right lifestyle choices, we might be able to slow down the process and keep progerin levels as low as possible.



National Institutes of Health, http://www.nih.gov
National Center for Biotechnology Information, http://www.ncbi.nlm.nih.gov/
University of California, San Francisco, http://www. ucsf.edu
University of Utah, http;//learn.genetics.utah.edu