X-Message-Number: 13959 From: "Terry Grossman" <> References: <> Subject: Freezing today vs. telomerase/cloning tomorrow Date: Fri, 16 Jun 2000 07:11:24 -0600 Several questions have appeared in the past few days questioning why freezing a tissue sample right now is even necessary or desirable, since we might simply depend on telomerase technologies (see yesterday's posting #13950) and the prospects that cloning of cells may reverse the clock. Telomere length is mostly a counting mechanism our cells use as a determining factor for apoptosis (programmed cell death). The truth is, as we age, most cells in our bodies carry out apoptosis before reaching a state of diminished telomere length. It is scientifically apparent that aging, along with associated cell loss, is caused by progressive free-radical damage, point mutations and problems within the DNA repair/copying mechanisms during the course of our lives (1). Even stem cells showing no telomere shortening likewise die as they are not immune to DNA damage. Telomeres have no way of protecting or repairing DNA damage, they are just a simple counting device. One company states they have taken 'normal', mortal, terminally differentiated cells and made them 'young' by returning these cells to a embryonic state allowing all genes to be expressed. However, this implies that if the DNA in the cells used in the technique are degraded and mutated, they are only creating primordial cells with damaged, less viable, and dangerous DNA prone to mutations that make themselves known in higher rates of cancer and cell death(2). Once again this suggests that the collection and storage of one's cellular sample as early as possible may be a very sound idea. Even if the above reasons for cell storage prove to be unfounded, as we become more able to detect and repair mutations in human DNA, it is certain these techniques will be far from free. Cryogenically storing a cell sample as early in life as possible can afford economic benefit. It is likely far fewer DNA repairs will be required. Our DNA receives 10,000 to 100,000 oxidative lesions each and every day. Although DNA repair enzymes are constantly at work removing this damage, they cannot keep pace. E.g., persons >70 years of age may have more than 100,000 oxidative lesions in the DNA of each and every cell (3). Even a span a small as ten years may make a great difference in one's DNA 'youthfullness', especially for those aged 40 to 75. (4) Freezing a tissue sample now for future reference is an inexpensive insurance policy. (1) Danith H. Ly, David J. Lockhart, Richard A. Lerner, Peter G. Schultz . (1999) "Mitotic Misregulation and Human Aging" Science 287: 2486-92. (2) Jing Wang, Gregory J. Hannon & David H. Beach. (June 2000)." Cell biology : Risky immortalization by telomerase" Nature 405, 755-756. (3) Ames, B.N., Shigenaga, M.K., Hagen, T.M. (1993). "Oxidants, antioxidants, and the degenerative diseases of aging." Proc. Natl. Academy of Science USA 90; 7915-7922. (4) Michikawa, Y. et al. (1999) "Aging-Dependent Large Accumulation of Point Mutations in the Human mtDNA Control Region for Replication." Science 286: 774-9. Long life and best wishes, Terry Grossman, M.D. Medical Director, Frontier Medical Institute 2801 Youngfield St., SDuite 117 Denver CO 80401 (303) 233-4247 Toll-free (877) LIV4EVR Subscribe to our free e-newsletter at www.liv4evr.com Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=13959