Aging is a worldwide disaster leaving nothing behind in a youthful state forever, but in the future it could probably be delayed for some time using the latest scientific discoveries. These discoveries would introduce the latest technologies to control and reprogram the genes and stem cells involved in aging. Restoration of youthful gene expression would enable cells to grow younger. Restoring the youthful gene expression may help turn back the clock on aging and potentially extend the healthy lifespan. Responsible factors could be of a genetic, nongenetic, and environmental origin [2, 27]. On the genetic side, this could involve modulating the expression of Klotho, AMPK, cyclin A2, FGF21, FOXN1, GDF11, Oct4, PGC-1, TGF-β1, apolipoprotein A-1, and I am not dead yet (INDY), the genes responsible for life extension [38–40].
On the environmental side, foods, nutrients, vitamins, and medications make us healthier probably because they induce the expression of health-promoting genes and reduce the expression of disease-promoting genes [21, 24, 46]. Conversely, the consumption of toxic substances including chemicals, smoke, drugs, and alcohol do the reverse.
Regenerative therapies concentrate their focus on stem cells and other life-extending factors and seek attention to reverse aging. Nevertheless, the potential of stem cells to be used as therapeutic cargo has had a profound effect on the vision of the future of regenerative medicine. Aged tissues have a limited stem cell reservoir, decreased population, and low renewal efficiency [11, 30]. All of these are the contributing factors for cellular senescence, apoptosis, autophagy, and oxidative stress, which finally accumulate and lead to aging [27, 47, 48].
Anti-aging therapies are a new emerging era of science that seem to benefit society using the power of stem cells, cytokines, and growth, regenerative, and life-extending factors. Future scientific discoveries will unravel these puzzles of aging biology. Probably, such life-extending factors mobilize the endogenous stem cells or renew or increase their number and functions . Regenerative therapies and exogenous stem cell transplantation into damaged tissues will also improve the wear and tear of aging.
Lessons from cancer biology may be vital to quench the historical quest for immortality [29, 49]. It seems that both cancer and aging share antagonistic features, and inhibition of one can cause the activation of the other. Cellular senescence, apoptosis, telomere shortening, and other mechanisms that protect us from cancer might accelerate aging [49, 50]. Similarly, longevity requires indefinite cell proliferation which might trigger cancer . Nonetheless, aging and cancer are tightly interconnected and seem to share common biological features. Now it is clear that both cancer and aged cells show DNA damage, genomic instability, and mutations [29, 49]. How do cancer cells fuel aging or how does aging fuel cancer? Are both cancer and aging the victims or the culprit of stem cell deregulation? Answers may push one more step forward in understanding the aging biology. Application of stem cell therapeutics to delay the aging process by improving cures for disease is clearer, but extension of human life apparently seems more remote. While animal models are well studied for extension of life , such translation from animal into human is more challenging.
Aging is not just due to local wear and tear. It is a process (a cumulative process of damage), and the process may be controlled in a significant way. Stem cells are an excellent candidate for regenerative medicine; however, it is important to understand that these miraculous cells may indeed be the future of medicine for mainstream cellular therapies of aging. Aging science is in its infancy, but it is clearly leading to the time when scientists will develop genetic engineering and stem cell therapies that will enable us to reverse aging and help us to grow younger and healthier.