Growing older is bittersweet. On the one hand it usually transmits a happier countenance, in part fueled by the resilience that wisdom and self-knowledge can bring. On the other, living longer — while a goal for most of us — inflicts age-related diseases such as arthritis and cardiac illness and spinal narrowing, as well as more laugh lines on one’s face. Getting older is often described as “being better than the alternative,” a term that I have heard anecdotally over the years from friends, patients and colleagues. Our source of happiness comes primarily by the relationships we have. As we age, we begin to lose our support system, and when this happens we become lonelier and more depressed.

We are living now at a time in aging research when it might indeed be possible to slow and even reverse human aging. Mouse experiments have demonstrated that a geriatric mouse with accompanying blindness can regain sight and return to a more vibrant age when youth-promoting genes are injected into it. This is an enormous breakthrough that might change human life expectancy. A Google search noted that life expectancy in our country “has risen from 39.4 years in 1860 to 78.9 years in 2020.” Medical advances, and access to medical information online, helped to increase human longevity. Many scientists believe that, as human society evolves and as medical knowledge increases, life duration will continually improve.

Distinct from the impact that medical knowledge and advances might have in lengthening our timelines, aging reversal is a potentially human intervention that supersedes the benefits of exercise and eating well. It occurs in mice when injected with genetic material that causes a return to biological youthfulness. While safety issues need to be explored in humans, the preponderance of the evidence leads to the conclusion that it is just a matter of time for age reversal to be available to human beings.

Since youth is a defense against many age-related diseases, this process will decrease the proclivity to develop geriatric illnesses as part of the aging process. Living much longer lives in a much healthier manner can significantly impact human happiness, fulfillment and gratification.

However, what consequences will occur as a result of a dramatically lengthened timeline? The Earth has finite space available for a growing population. Populating other planets will become an integral part of adapting to the increase in the sheer numbers of people on Earth. The number and types of jobs will also evolve as people live longer; however, the exponentially advancing computer world will make many jobs obsolete. Artificial intelligence shows promise for reading X-rays more accurately than human radiologists can. Generative computing will be able to write books and poems and songs without having any humans involved in the process. As our lifespan increases with genetic interventions, and as software programs crescendo into making life much easier for people on Earth, existing in the future will likely be a much more user-friendly process than it is in 2023.

At the same time that we are researching and understanding aging, scientific research has revealed some interesting facts about the aging process on a cellular and microscopic level. The body is populated with tissue cells that are differentiated and specific to various organs in our body. For example, the liver is composed of a network of cells that is unique and distinct from the cells that we find in blood, kidney, lung, brain and heart.

The earliest cell, however, is the stem cell. It is a nave cell and has not yet differentiated into a specific and unique cell type that can choose to become literally anything cellular that is needed in the body. This cell is like a baseball player who can succeed playing any role on the team, from pitching to batting to running. However, even if there is a multi-potential baseball player, to play each of these positions requires specific knowledge. Hitting a home run requires a different skill set than being a pitcher or covering left field. Like a stem cell, the multi-potential baseball player can move to any place on the field and develop into what specific skill set is most needed. This hypothetical stem cell can produce more stem cells or, alternatively, grow into specific healthy cells, such as blood cells, that can function effectively while starving out, as an example, the cancer cells in the blood.

The stem cell, like a multi-potential baseball athlete, can specialize in a specific organ and turn into the cells that manage that organ. Thus a stem cell can turn into any cell for a specific part of the body. What is unique about stem cells is that they can actually replicate individually and specialize in whatever organ system needs a more healthy and functional cellular framework.

Dr. Shiri Gur-Cohen, a stem cell biologist and researcher at the University of California San Diego, provides a taped lecture on the University of California television system to discuss research results. This link, https://signerlab.com/news, brings the viewer to the SignerLab at UCSD, where aging and stem cell research is being evaluated. The lecture by Dr. Gu-Cohen can be watched from this link: https://www.youtube.com/watch?v=eFMfZvYvE9I. The lab she runs can be reached with this link, https://gurcohenlab.com/people.

It is notable in this video that billions of cells are lost and replaced each day. Skin cells in infants can be rejuvenated within only two weeks, whereas in adults this decreases to every 50 days. As an analogy, we are very different people molecularly from one day to another as our bodies constantly regenerate. The analogy can been applied also to Air Force One, which is constantly “regenerating” by replacing all parts before any of them age and become dysfunctional. A documentary video hosted years ago by journalist Sam Donaldson discussed the longevity of the president’s jet. Donaldson noted that eventually every part of Air Force One is replaced by new parts and materials. It doesn’t age in the same natural way that our bodies do; however, with indigenous stem cells and with stem cell treatments, the body, like Air Force One, constantly regenerates and replaces diseased cells.

The UCSD lab is a trailblazer in aging research. Dr. Gur-Cohen discusses what occurs when a stem cell is transported from a young mouse to an old one. One might think that since it is from a healthy and young mouse that when it is transported into an aging mouse it helps to stop aging or reverse it. In fact the opposite occurs and the young stem cell loses its ability to create more stem cells, and it becomes corrupted by an “old” environment and ceases to behave as it had when it was in a younger and healthier mouse. However, if a stem cell is taken from an old mouse, where it has lost the ability to replicate, and transported into a young mouse, the stem cell behaves just like a stem cell in a young and vibrant mouse. This proves the importance of the environment on cell function. Therefore, at least in this experiment, the cellular microenvironment is the more powerful context for stem cell function and its impact on the body.

Although this seems very promising, it is also a concern that stem cells may be responsible for fueling a cancer. The stem cell life is much longer than other cells, and a risk associated with cellular longevity is that it provides more time for a genetic mutation to occur. Such a mutation could spur a potentially invasive carcinoma. It is not necessary that there be a large number of genetic mutations. Even a few mutations may have the impact of causing a stem cell to lose complete autonomy over regeneration into more stem cells. Once this regenerative capacity is destroyed, the cancerous stem cells have no self-regulation and continue to grow and cause cell death.

As research technology evolves, there is much hope that stem cells could repair organs and reverse aging in human beings. In addition to the science, it is necessary to develop a new domain of ethical medicine that can provide a forum for discussion. If people, for example, can be transported genetically to an earlier time of life, it will be mandatory to look at the economic impact of this on work, employment, romantic relationships and career choice. Discovering the Fountain of Youth will likely bring both good and bad. The scientific miracle of preventing diseases, restoring longevity and improving health via stem cell research cannot be devoid of some negative consequences.

These issues could demand that humans inhabit another planet due to lack of space available on our planet. If everyone who wishes to could be rejuvenated to an earlier age, then the Earth, with its limitations, wouldn’t be able to physically hold this burgeoning population. It is interesting that the human species is moving simultaneously into age reversal and space exploration, finding a way to live longer biologically and begin the process of inhabiting other places in the universe.