The reference used by the manufacturer of the astragaloside IV dietary supplement to substantiate its use does not even mention astragaloside IV, it only mentions that telomere dysfunction is involved in DNA damage.
It is true that telomeres shorten in most tissues during aging. But there is question as to whether this is a cause or an effect. The citation itself admits telomere therapy is “under debate.” The experiment in the study was a test-tube study, not a study to proven longevity in mammals or humans. Telomere shortening is described as a marker, not a promoter of longevity per se. [Proceedings National Academy Sciences August 12, 2008 vol. 105 no. 32 11299-11304]
There is no published evidence, so far, to show that astragaloside IV activates or inhibits telomerase. The discussion concerning astragaloside IV and telomerase apparently has arisen from a recently filed patent application, but patents are sometimes approved with virtually no evidence of their viability.
For awhile there was hope that the use of telomerase, an enzyme that can regenerate the tips of chromosomes as they are shortened with aging, would become a longevity treatment. But all cancer cells activate telomerase and become immortal, so this approach is still in question. [Science 1994; 266: 2011-15] Studies also reveal that telomerase deficient mice do not age prematurely. [Cell 1997; 91: 25-34]
Resveratrol has been demonstrated to prevent the senescence of cells by increasing telomerase activity in healthy cells. [Br J Pharmacol. 2008 Jun 30] However, resveratrol inhibits telomerase activity in tumor cells. [Int J Oncology 2006 Mar;28(3):641-8] This is desirable since high levels of telomerase activity are a hallmark of cancer. [Current Stem Cell Research There 2007 Jan; 2(1):31-8]
As researchers have clearly stated, “telomere shortening apparently has a dual role in tumor development and progression. One the one hand, it induces chromosomal instability and the initiation of cancer; on the other hand, tumor progression requires stabilization of telomeres.” [Hepatology. 2004 Aug; 40(2):276-83] What telomerase apparently does is induce cells to die off before they become cancerous.
It is true that telomere length at advanced age is a biomarker that predicts survival. Twins with the shortest telomeres have a three times greater risk of death compared to their co-twin with longer telomere measurement. [Aging Cell. 2007 Dec; 6(6):769-74]
But it is also true that mammals with the longest telomeres (mice) have the shortest lifespan. A decrease in mean telomere length might result in, on the one hand, an increased life span and, on the other, a higher risk of cancer. [Med Hypotheses 2006; 67(1):157-60]
Telomere stabilization may end up immortalizing cells, which is the precise state of a cancer cell – it never matures, ages and dies off. It is immortal. [J Am Geriatr Soc. 2005 Sep; 53(9 Suppl):S292-4]
Fortunately, even though the advertised dosage of astragaloside IV is a hefty 33 milligrams in the aforementioned dietary supplement, it is very poorly absorbed due to its large molecular size and difficulty obtaining passage through the intestine. [Eur J Drug Metab Pharmacokinet. 2006 Jan-Mar; 31(1):5-10] Bioavailability studies show that only about 2.2% to 3.6% of astragaloside IV is bio-available in rodents. [Basic Clin Pharmacol Toxicol 2004 Dec;95(6):295-8; Eur J Drug Metab Pharmacokinet 2005 Oct-Dec;30(4):269-73] So this supplement may exert little if any biological activity. This is an unknown.
It is interesting to note that another small molecule, generally considered as an estrogen-like molecule, genistein from soy, enhances telomerase activity, which results in the proliferation of cancer cells in mice. Researchers claim genistein “could be detrimental” to prostate cancer patients. [Carcinogenesis. 2007 Nov; 28(11):2282-90] What does that say about astragaloside IV?
There is an association between longer telomeres and better health in centenarians. [J Gerontol A Biol Sci Med Sci. 2008 Aug; 63(8):809-12] But again, does this mean the longer telomeres promoted health, or were a consequence of other healthy practices?
The suggested use of astragaloside IV appears to be scientifically premature at the very least, and possibly imprudent given issues over its role in the proliferation of cancer.
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