Aging and its associated aches and pains are typically considered a rite of passage— unavoidable despite how well we care for ourselves. However, a new report published this month in Nature Communications challenges this thought.
Drs. Niedernhofer and Haurd believe aging represents a loss of cells to regenerate in responds to stress. For example, at younger ages, a fall might cause a few days of tenderness, but the same stress in your 70’s may result in more long term damage. They argue this happens because the body is no longer able to regenerate the damaged tissue.
In the current study, the authors isolated a pool of stem cells from muscle tissue, noting that as the cells aged they lost their ability to proliferate, differentiate and regenerate.
Interestingly, by using mice with accelerated aging, they were able to show that transplantation of young muscle stem cells could rescue the aging mouse and increase its lifespan. Typically, these mice lived for an average of 21 days, but when the researchers transplanted young muscle stem cells into their bodies, their lifespan more than doubled.
Interestingly, further experimentation revealed the beneficial effect was not due to the cells themselves reconstituting the aging tissue, but rather due to a compound secreted by the young stem cells that actually induced changes in the old stem cells. The old cells, when cultured with the young cells, began to act young again, with increased proliferation and differentiation.
The ability to divide and self-renew, as well as differentiate into a broad type of specialized cells, defines a stem cell. Two main types of stem cells exist: embryonic and adult. Embryonic stem cells have the capacity to develop into any of the hundreds of tissue types that comprise the human body. Given their capacity for self-renewal and plasticity, scientists have long proposed their use for regenerative medicine and tissue replacement.
Although promising, much controversy revolves around the scientific use of embryonic stem cells and thus has driven the research of adult stem cells. Adult stem cells are capable of renewal, similar to embryonic cells. However, adult stem cells are usually limited in their ability to differentiate into certain types of cells.
For more than 40 years, bone marrow stem cells have been used to treat a wide range of blood conditions, both cancers and chronic conditions, such as leukemia and sickle cell disease. Bone marrow stem cells have had success treating some disorders, but they are limited, thus promoting the research of other adult stem cell types.
The research presented in this study is still in its infancy, and the long-term effects of stem cell transplantation in to the human body are currently unknown. Despite this, clinics outside the United States have begun to offer patients promises of restored vitality. The unauthorized procedures claim to restore joints, tendons or ligaments and target patients who are desperate and willing to try therapies not yet approved by the FDA.
Regardless of the potential benefit of these new techniques, so many questions about safety and efficacy still remain.
The reality is the ability of these tissues to renew endlessly should make patients cautious, as this is a shared characteristic with a tumor. Studies need to be undertaken in order to better identify the exact compounds that restores cell function. Furthermore, the safety and long term impact of these cells need to examine thoroughly before we begin promising patients a “fountain of youth.”
Dr. David B. Samadi is the Vice Chairman of the Department of Urology and Chief of Robotics and Minimally Invasive Surgery at the Mount Sinai School of Medicine in New York City. He is a board-certified urologist, specializing in the diagnosis and treatment of urological disease, with a focus on robotic prostate cancer treatments. To learn more please visit his websites RoboticOncology.com and SMART-surgery.com. Find Dr. Samadi on Facebook.