Telomeres are likely to impact on your life (indeed, most likely are already doing so), so for those who aren't familiar with them, telomeres are repeated segments of nucleotides found at the ends of chromosomes, and are described by Carol Greider, a professor here at Johns Hopkins and Nobel prize winner for her work on telomerase, the enzyme that helps form them, in this way: they're like the plastic ends of shoelaces, designed to protect the shoelace itself from unraveling. In the case of telomeres the assumption is they protect the actual chromosomal DNA during the process of replication, and as a cell replicates over its lifetime they get shorter and shorter. Turns out that how long these ends are is important in an increasing range of diseases, and in this week's PodMed, Rick and I discuss the impact of telomere length on susceptibility to an experimental model of the common cold, as published in JAMA.
Before describing the study, first of all let me say how much I admire these hearty souls who volunteer for such studies! While I have stepped forward for a range of studies here at Hopkins, I'm not sure what would induce me to voluntarily expose myself to a cold virus or other infectious disease. So to those 152 study subjects, thank you. All of the subjects lived in the Pittsburgh area and were 18 to 55 years of age, were in good health and took no regular medications outside of birth control pills, and had no chronic health problems.
All subjects had blood drawn for multitude of assessments, one of which was telomere length as seen in their leukocyte or white blood cell population, as these are the cells known to be involved in fighting off many infectious agents. Subjects were quarantined and administered nasal drops containing a common cold virus, and then monitored for 5 days to determine whether infection occurred. The study found that shorter telomere length was associated with greater susceptibility to infection, and advancing age was also associated with shorter telomeres, so older age and shorter telomere length conferred the greatest risk of infection.
Rick points out in the podcast that when researchers corrected for age, it turns out that shorter telomeres were independently associated with greater infection risk. This observation fits with other studies showing that short telomeres are also associated with some types of cancer and development of chronic illness. These conditions, of course, also increase in incidence as people age so clearly the question of the independent contribution short telomeres make to illness and disease susceptibility will remain under investigation. I predict in the podcast that telomere length assessment may some day soon be part of routine clinical testing to develop a composite picture of overall health, and perhaps may be a target for intervention at some point. You heard it here first, folks.
Other topics this week include a comparison of robotic hysterectomy with standard laparoscopic surgery in JAMA, and a new device for the treatment of GERD and volume resuscitation with starch in NEJM. Until next week, y'all live well.
Telomere Length and Health,5 Comments