Telomere Length Important for Health
Elizabeth Blackburn (who won the Nobel Prize for medicine in 2009) gave a spectacular plenary lecture at the 2013 meeting of the American Psychiatric Association, in which she described the role of telomeres in psychiatric and other medical disorders. Telomeres are the strands of DNA at the end of each chromosome that protect the integrity of the DNA each time the cell replicates. The end is capped to prevent damage, degeneration, and genetic instability. A minimum length must be maintained for the protection of the cells.
Telomeres shorten with aging and with each cell replication. They also shorten as a function of childhood adversity, stressors in adulthood, and number of episodes of depression. When a cell’s telomeres get too short, the cell enters a period of senescence, meaning it no longer replicates. Senescence is associated with a variety of adverse events, including the possibility of apoptosis (cell death), pro-inflammatory effects, and pro-tumor effects. The cell can begin to resemble a rotten apple that spreads its ill effects to others nearby. These effects can predispose a person to diseases such as diabetes, depression, attention deficit hyperactivity disorder (ADHD), anxiety disorders, pulmonary fibrosis, aplastic anemia, cardiovascular disorders (stroke and heart attack), osteoarthritis, immune abnormalities, dementia (in women), and premature aging.
Certain lifestyle alterations can increase telomere length, such as mindfulness/yoga training, exercise, sleep, omega-3 fatty acids, and having a positive purpose or meaning in life. Telomeres can also be lengthened by a synthetic enzyme called telomerase.
Other lifestyle factors can shorten telomeres or make telomerase less effective. Chronic stress can decrease the activity of telomerase by 50%. For people serving as the caregiver of a loved one, the longer the duration of this stress, the shorter the length of telomeres. High levels of what Blackburn described as cynical hostility also decrease telomere length.
Editor’s Note: Here we have more evidence that stress can affect our genes. We have written before about epigenetics, the study of the process by which environmental events such as stress can leave behind methyl and acetyl groups on DNA and histones that affect how easily DNA is turned on or off. Now it seems that stress can also have profound effects on the telomeres that cap each strand of DNA and keep it stable. An overly high proportion of short chromosomes is associated with a range of psychiatric and medical illnesses. This type of non-hereditary influence on genes could mediate some of the long-term effects of the environment on health. The good news for patients with bipolar disorder is that M. Schalling et al. found that treatment with lithium lengthened telomeres. Perhaps the bottom line of this whole collection of fascinating data is: Take good care of your telomeres, and they will take care of you.
