Anti-Aging Strategy May Help HCV Liver Transplant Recipients
By evaluating one of the cellular components of senescence (the period of decline in health and function associated with aging), British researchers have identified a reason that liver transplant recipients are particularly susceptible to degenerating health. Since the Hepatitis C virus (HCV) is the most likely reason for a liver transplant in the United States, those with advanced HCV are more vulnerable to this characteristic of aging. Although the medical community is just beginning to unravel some of the biological factors involved in senescence, those with HCV who need a liver transplant can capitalize on the knowledge garnered thus far.
Three American scientists were awarded the 2009 Nobel Prize for Physiology and Medicine for their discovery about aging. Involving how chromosomes are copied during cellular division, these scientists identified telomere length as a predictor of health and longevity.
Crucial for cellular division, telomeres are protective DNA-protein complexes positioned at the tips of chromosomes:
- When cells divide, the exact sequence of DNA must be transcribed from the chromosomes of the parent cell to create chromosomes for the new cell.
- A piece of the telomere is clipped off and donated to the DNA sequence at the end of the chromosome so that the copying is complete and accurate.
- Most cells normally divide about 50-70 times, their telomeres getting progressively shorter until the cells lose their ability to divide, sustain genetic damage (which can cause cancer) or die.
Telomeres and Liver Transplant Recipients
On the heels of recognizing shortened telomere length as a hindrance to health and longevity, William Gelson from the University of Cambridge and colleagues investigated whether liver transplant recipients demonstrated this unwanted feature of senescence in immune cells.
As published in the May 2010 issue of Liver Transplantation, the British researchers found this marker of senescence to be accelerated in those with Hepatitis C who undergo liver transplants. Gelson and colleagues found that the telomeres of an important immune cell (lymphocytes) were significantly shorter in liver transplant recipients compared with control subjects. These findings suggest that besides immunosuppressive drugs used to prevent organ rejection, weakened immunity leading to complications (infections and cancers) in transplant patients may be attributable to senescence of the immune system – as identified by lymphocytes with shortened telomeres.
These findings suggest that liver transplant recipients may experience faster immune cell aging, which could help explain their increased rates of infections, cancer and other serious conditions.
Keeping Telomeres Long
While modern science is still a long time away from discovering the fountain of youth that prevents senescence, many experts believe that antioxidants represent the best defense against aging and illness.
As published in the July 2002 edition of the journal, Trends in Biochemical Sciences, researchers from the University of Newcastle found that oxidative damage is repaired less well in the DNA of the telomere than elsewhere in the chromosome. Additionally, it was determined that oxidative stress accelerates telomere loss, whereas antioxidants decelerate it.
For decades, increasing the dietary consumption of antioxidants has been considered to be a superior strategy for retaining one’s youth and healthfulness. However, our new understanding of telomere length in liver transplant recipients gives those with late stage HCV infection more incentive than ever to indulge in antioxidants. Because shortened telomeres are more abundant following a liver transplant – and they foretell of a shorter life span – strategies to preserve telomere length (such as antioxidant consumption) will emerge as paramount to delay senescence in HCV liver transplant recipients.
http://nobelprize.org/nobel_prizes/medicine/laureates/2009/press.html, The Nobel Prize in Physiology or Medicine 2009, Retrieved July 11, 2010, Nobel Web AB, 2010.
http://www.all-things-aging.com/2010/06/telomeres-aging-and-cancer.html, Telomeres, Aging and Cancer, Constance McCloy, PT, EdD, Retrieved July 11, 2010, All Things Aging, 2010.
http://longevity.about.com/od/whyweage/a/senescence.htm, Senescence, Healthy Aging and Longevity, Mark Stibich, PhD, Retrieved July 11, 2010, About.com, 2010.
http://www.hivandhepatitis.com/hep_c/news/2010/0709_2010_c.html, Immune Cells Show Signs of Senescence after Liver Transplantation, Liz Highleyman, Retrieved July 10, 2010 hivandhepatitis.com, 2010.
http://www.ncbi.nlm.nih.gov/pubmed/12114022, Oxidative stress shortens telomeres, von Zglinicki T, Retrieved July 11, 2010, Trends in Biochemical Sciences, July 2002.
http://www.ncbi.nlm.nih.gov/pubmed/20440767, Features of immune senescence in liver transplant recipients with established grafts, Gelson W., et al, Retrieved July 11, 2010, Liver Transplantation, May 2010.
http://www.springerlink.com/content/jw847g541l435103/, Cellular senescence, ageing and disease, D.G.A. Burton, Retrieved July 11, 2010, Age, March 2009.
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