It’s no surprise that the number of senior citizens in the U.S. is on the rise. In fact, it’s estimated that in the next fifteen years the percent of U.S. residents 65+ will nearly double.1 So the focus on aging and its far-reaching effects – including how to treat, and even prevent, age-related diseases – has become more important than ever.
Is there a way to slow down the aging process?
It might not be just a pipe dream. Scientists think one key to longer life spans may be linked to the body’s ability to replenish its stem cells. Stem cells play a vital role in regenerating and repairing fundamental tissues and cells in the body (like joints and blood vessels) that keep us alive and kicking. One researcher, Henne Holstage, says “It’s estimated that we’re born with around 20,000 blood stem cells, and at any one time, around 1000 are simultaneously active to replenish blood.2” So, once these cells begin to expire, so does the body’s ability to produce new blood and immune cells.3
Enter the mighty telomere!
Each time a stem cell divides to create new cells, telomeres, the protective tips found on the ends of the cell’s chromosomes, get shorter. Once they get too short, a cell can no longer divide and becomes inactive or dies off. This shortening has been associated with aging, cancer, type 2 diabetes, Alzheimer’s disease and a higher risk of death.4,5, 6, 7
Holstage sees a day when scientists may be able to slow down or even reverse some age related effects by replenishing the body’s blood stem cell stock using younger cells saved from birth or early life2 from sources, such as cord blood, that contain longer telomeres.
Studies have found that compounds in the blood of young mice awaken stem cells and rejuvenate aging tissue in the heart, muscles and brains of old mice.8,9,10 Scientists are now moving on to studies on people to see if the human equivalent in younger blood will have a similar effect on older adults. One of the first studies, evaluating the safety of plasma from young donors to treat symptoms of Alzheimer’s disease, is currently underway at the Stanford School of Medicine.11
References:
- Ortman, Jennifer M., Victoria A. Velkoff, and Howard Hogan. An Aging Nation: The Older Population in the United States, Current Population Reports, P25-1140. U.S. Census Bureau, Washington, DC. 2014.
- Coghlan, Andy. Blood of world’s oldest woman hints at limits of life. New Scientist, April 23, 2014.
- Holstege H et al., Somatic mutations found in the healthy blood compartment of a 115-yr-old woman demonstrate oligoclonal hematopoiesis. Genome Res. 2014;24(5):733-42
- Risques, R.A., et al. (2008). Ulcerative colitis is a disease of accelerated colon aging: evidence from telomere attrition and DNA damage. Gastroenterology 135, 410–418
- Townsley, D.M., et al. (2014). Bone marrow failure and the telomeropathies. Blood 124, 2775–2783; Wang, J., Sun, Q., Morita, Y., Jiang, H., Gross, A., Lechel, A., Hildner, K., Guachalla, L.M., Gompf, A., Hartmann, D., et al. (2012). A differentiation checkpoint limits hematopoietic stem cell self-renewal in response to DNA damage. Cell 148, 1001–1014
- Begus-Nahrmann, Y., et al. (2009). p53 deletion impairs clearance of chromosomal-instable stem cellsin aging telomere-dysfunctional mice. Nat. Genet. 41, 1138–1143.
- Sharpless, N. E., et al. (2007). How stem cells age and why this makes us grow old. Nature Reviews Molecular Cell Biology. 8(9):703-713.
- Loffredo, Francesco S. et al. (2013). Growth Differentiation Factor 11 Is a Circulating Factor that Reverses Age-Related Cardiac Hypertrophy. Cell. 153(4):828-839.
- Sinha M, et al. (2014). Restoring systemic GDF11 levels reverses age-related dysfunction in mouse skeletal muscle. Science . 344(6184):649-652.
- Saul A Villeda,, et al. (2014). Young blood reverses age-related impairments in cognitive function and synaptic plasticity in mice. Nature Medicine 20 (6):659-63.
- ClinicalTrials.gov NLM Identifier: NCT02256306. Accessed 10/20/15