Scientific Quest For Lasting Youth

The human body has an enormous tendency to regenerate itself from any external or internal injury. You may have heard of the regeneration of damaged liver, regeneration of lungs and improved breathing after chronic smoking, healing of internal ulcers and external wounds. Nowadays, we may also hear the news of people and celebrities taking stem cell therapy for their joint injury or for their wrinkled skin. Stem cells are special cells present in all stages of human life that possess the ability to self-renew and differentiate into multiple cell lineages. It is classified as Totipotent, Pluripotent and Multipotent stem cells based on its potency. 

Totipotent cells are stem cells that can form the whole organism. Embryonic stem cells are totipotent stem cells. Pluripotent stem cells can form all types of cells, while multipotent cells can form many of the specific cell lineages. Embryonic stem cells are present in the 5-6 day blastocyst (a phase in the development of the zygote), so their usage comes with ethical concerns. Japanese Researcher Shinya Yamanaka devised induced pluripotent stem cells (iPSCs) by reprogramming somatic cells like skin cells with transcriptional proteins Oct3/4, Sox2, Klf4, and c-Myc, which are exclusively found in embryonic stem cells. 

Ageing 

Ageing is the inevitable physiological decline of the human body. Our cells also undergo a rapid aging process along with the replenishment of new cells. In a single day, we lose and replace 50-70 billion cells. I know who I “was” when I got up this morning, but I think I must have changed several times since then. Stem cells are the basis of the regeneration of the human body. The regenerative potential of stem cells declines after we reach a certain age. 

Anti-ageing simply means putting more healthy years into your existing life rather than increasing your age. Modern science is expending all its resources to retain the regenerative potential of stem cells even in old age.  The search for the “fountain of youth” started from the very beginning. We have heard stories about the mythical spring, which restores vigour when bathed in or drunk water from it. It was not only mentioned in the writings of Herodotus, in the romance of Alexander, in the stories of Prester John, but also in the Hindu mythology. The famous “samundra manthan” for “amrit”. 

In addition, “chiranjeevi bhawa”, a common blessing from the elders, signifies the evidence and possibility of living healthily for more years. I remember my dad complaining about his grey hair and his not-so-wrinkly face whenever he used to shave in front of the mirror. This clearly indicates his quest for youth. There are several theories of ageing, including the theory of weakness of the five viscera, the theory of weakness of the kidneys, the theory of weakness of the spleen and stomach, the theory of imbalance of yin and yang, the theory of liver depression, and the theory of phlegm and blood stasis. In eastern philosophy, the Five Element Theory defines the balance of fire, earth, metal, wood, and water for health and aging.

Stem cells contribute to the anti-ageing process through three primary mechanisms. They facilitate tissue repair by undergoing division and differentiation to regenerate damaged or aged tissues. Similarly, they modulate the body’s metabolic activities by secreting growth factors that can influence cellular function and vitality. They assist in regulating the inflammatory response, which is crucial for maintaining immune system balance and preventing age-related inflammation. 

Clinical trials have just started employing the transplantation of brain cells isolated from human foetuses into Parkinson-diagnosed patients to assess the procedure’s efficacy while minimising the possible side effects. One of the research projects used human-foetus-derived dopaminergic neurons and transplanted them into Parkinson patients' depleted striata. Research has demonstrated functional recovery after successfully transplanting dopaminergic neurons from monkey embryonic stem cells into the patients' brains. 

It has also been evident that mesenchymal stem cells could produce neurotrophic factors to stimulate endogenous neurogenesis, angiogenesis, and neuronal defence systems. In addition, research has indicated that MSCs could alleviate memory impairments and reduce the amount of A in Alzheimer’s disease mouse models by upregulating interleukin-10 and vascular endothelial growth factor while modulating microglial activation in the brain. The limitation is that it only balances the degenerative process occurring in the Alzheimer's brain but does not treat the underlying pathology. 

Stem cells in amalgamation with tissue engineering have been prolific interventions in repairing external and internal tissue injury. There is a successful transplantation of the head of the third metacarpal construct into the middle finger of the patient, with the existing bone connected to the metacarpal bone construct using a titanium plate. Similarly, medical science has successfully treated microtia with reconstructed ears after three months of surgery. 

One of the present-day examples of anti-aging is Bryan Johnson, a tech millionaire. He performed the world’s first multi-generational plasma exchange with his 17-year-old son in 2023. Young Plasma, which is collected from 18-25-year-olds, has been proven to repair skeletal, vascular, muscular, major organ, and cognitive deterioration associated with ageing. It has shown to delay or reverse the aging process, boost energy levels, speed up recovery from injuries, and reduce adrenal fatigue in patients with autoimmune disorders.

Immune cells 

Embryonic stem cells are primarily made from the cells found in a human blastula, one of the earliest stages of human life. A fertilised egg grows into a blastula (made of 100 cells), which can only survive for a short time before it must be implanted in a womb. The pro-life group believes that life is conceived at or after conception. Another ethical dilemma with stem cells is tumorigenicity and immune rejection. The high dose of stem cells will probably cause tumour formation. The regulatory mechanisms of how stem cells interact with immune cells in vivo remain largely unexplored, limiting their widespread clinical application. Future research should focus on elucidating the immunomodulatory roles of stem cells to establish a foundation for developing improved stem cell-based therapies for chronic systemic disease and regeneration.

(The author is doing his master's in Pharmaceutical Sciences at the University of the Eastern Shore, USA.)