From around age forty we start to lose muscle mass due to various aging processes, one of these processes is the accumulation of senescent cells. Senescent cells are simply cells that have become damaged or have reached their maximum number of divisions. Normally these cells are shut down by a kind of self destruct program inside the cell, ready to be disposed of by the immune system.
However as the immune system ages, it stops clearing house properly, leaving many of these senescent cells in place. This would not be such a big deal, but senescent cells actually send out toxic inflammatory signals that block tissue regeneration. This includes the compromised formation and repair of muscle tissue[1-2]. Some researchers suggest that removing senescent cells could potentially lead to better performance and extending peak, allowing you to enjoy sports and remain competitive for longer.
There have been some interesting results on cardiovascular health and performance seen in pre-clinical studies so far. In tests aged mice had significantly improved vascular health when treated, compared to control mice left to age normally[3-4]. Perhaps even more exciting is the discovery that this therapy can also make an impact on heart disease. So reducing senescent cells could be a route to better cardiovascular health and improved fitness as we get older[5].
So isn’t this like steroids?
Steroids are drugs that mimic certain natural hormones in the body that regulate and control how the body works and develops. Anabolic steroids are often used for sports, mainly because they are similar to the male hormone testosterone and they can improve endurance and performance, and stimulate muscle growth. Some people take anabolic steroids to help build muscles or to improve how they perform at sports, such as running and cycling. However using steroids is known to carry a variety of health risks.
Removing senescent cells from the body is nothing like this. It is really just helping the body to clear out the junk it struggles with as we age, and optimise its natural repair functions. Your body is designed to maintain a delicate balance known as homeostasis, but as you age that balance is gradually lost, what science is trying to do is help you to keep that balance and peak performance for longer.
The clues are already in nature
You have likely heard the phrase “An apple a day keeps the doctor away”, but there could be more truth to this saying than you might think.
Quercetin, one of the compounds that some studies suggest can remove senescent cells, is naturally found in apples and other fruits and vegetables [6-7]. An apple contains around 4.4 milligrams of quercetin for every 100 grams of apple. With a medium-sized apple being typically around 150 grams, it could contain up to 10 milligrams of quercetin. However to get a similar dose used in these studies for health purposes you would need to eat fifty apples a day!
Obviously unless you really like apples a lot this is completely impractical. This is why researchers have extracted pure quercetin from these foods, and it can be obtained cheaply as a dietary supplement with an effective and safe dosage.
So really, there could be some truth in the old saying about apples, after all.
Improving your body’s natural balance to maintain health
That said, there is always room for improvement. What science is doing now is investigating why these natural substances help your body maintain balance, and finding ways to improve upon this. The hope is that the longer your body can maintain homeostasis the longer you can enjoy your favorite sports, hobbies and benefit from an independent and active life.
As is the case in science there are of course no certainties, more studies need to be made before we can be sure these results will translate. However some will be entering human clinical trials in the near future so answers should not be too far behind. Companies like Unity Biotech, Oisin Biotechnology and Cellage are busy developing improved versions of these first pass therapies to make them even more effective and safe.
Hopefully we can all look forward to a healthier life thanks to progress like this, only time will tell.
Literature
[1] Baker, D. J., Wijshake, T., Tchkonia, T., LeBrasseur, N. K., Childs, B. G., Van De Sluis, B., … & van Deursen, J. M. (2011). Clearance of p16Ink4a-positive senescent cells delays ageing-associated disorders. Nature, 479(7372), 232-236.
[2] Sousa-Victor, P., Gutarra, S., García-Prat, L., Rodriguez-Ubreva, J., Ortet, L., Ruiz-Bonilla, V., … & Perdiguero, E. (2014). Geriatric muscle stem cells switch reversible quiescence into senescence. Nature, 506(7488), 316-321.
[3] Zhu, Y., Tchkonia, T., Pirtskhalava, T., Gower, A. C., Ding, H., Giorgadze, N., … & O’Hara, S. P. (2015). The Achilles’ heel of senescent cells: from transcriptome to senolytic drugs. Aging cell, 14(4), 644-658.
[4] Roos, C. M., Zhang, B., Palmer, A. K., Ogrodnik, M. B., Pirtskhalava, T., Thalji, N. M., … & Zhu, Y. (2016). Chronic senolytic treatment alleviates established vasomotor dysfunction in aged or atherosclerotic mice. Aging Cell, 15(5), 973-977.
[5] Childs, B. G., Baker, D. J., Wijshake, T., Conover, C. A., Campisi, J., & van Deursen, J. M. (2016). Senescent intimal foam cells are deleterious at all stages of atherosclerosis. Science, 354(6311), 472-477.
[6] Zhu, Y., Tchkonia, T., Pirtskhalava, T., Gower, A. C., Ding, H., Giorgadze, N., … & O’Hara, S. P. (2015). The Achilles’ heel of senescent cells: from transcriptome to senolytic drugs. Aging cell, 14(4), 644-658.
[7] Hollman, P. C., van Trijp, J. M., Buysman, M. N., Mengelers, M. J., de Vries, J. H., & Katan, M. B. (1997). Relative bioavailability of the antioxidant flavonoid quercetin from various foods in man. FEBS letters, 418(1-2), 152-156.
