In 1996, cryobiologist Gregory Fahey visited a doctor’s office to discuss administering a month’s worth of growth hormone. His optimism was bolstered by a pivotal study on rats1. These injections aimed to facilitate the regeneration of the thymus gland, an essential immune organ that diminishes significantly with age. Fahey hypothesized that thymus regrowth could correlate with longer, healthier lives.
Tech giants are hacking their bodies to live longer. Is there science behind their method?
According to MRI scans, Fahey observed a significant increase in his functional thymus mass, nearly doubling in size2. Yet, the subjective benefits of this regrowth were less tangible. At just 46 years old and in good health, he remarked that subsequent tissue regeneration left him feeling “energized and invincible.”
What began as an informal experiment transformed into a series of small clinical trials conducted by Interven Immune, a biopharmaceutical firm in Torrance, California, where Fahey serves as Chief Scientific Officer.
Interest in thymus research has surged over the past three years, fueled by new literature suggesting that thymus health could be a significant indicator of overall well-being. Excitement peaked when recent studies revealed a correlation between decreased thymus health and a heightened risk of mortality3,4.
Investor interest is palpable. In January, TECregen, a biotechnology company based in Basel, Switzerland, raised 10 million Swiss francs (approximately US$12.4 million) to create a thymus-regenerating treatment aimed at slowing the aging process and preventing cancer. The specifics of their drug candidates remain undisclosed. Last October, Zag Bio, another thymus-focused biotech company in Cambridge, Massachusetts, launched with $80 million in funding. Venture capitalists and pharmaceutical firms are actively engaging with Fahey and his peers to initiate their own research programs. “There’s significant interest in this field right now,” states Marcel van den Brink, attending physician and director at City of Hope, a cancer hospital in Duarte, California. He notes a paradigm shift, expressing that there is now a “huge awareness” of the importance of thymus research.
Understanding the Thymus: A Neglected Organ
For many years, the thymus was regarded as a remnant with limited significance. Georg Hollander, co-founder of TECregen and immunologist at the University of Oxford, remarked that it has been “forgotten” and “neglected.” In the 1920s, some researchers even speculated that the organ’s role was minimal in mammals, while Nobel laureate Peter Medawar dismissed it as “an evolutionary accident of little importance.”
How the brain controls aging — and why zombie cells are the key
However, this perception was misguided. The thymus’s crucial function went unnoticed for decades, partly due to observations that mammals without thymuses appeared healthy. This changed in the 1960s when immunologist Jack Miller discovered the organ’s vital role after conducting experiments on newborn mice5. Puppies lacking thymus glands often succumbed to infections due to sparse immune cell presence.
Miller elucidated that the thymus gland produces T cells, which are essential components of the immune system responsible for attacking cancer cells and combating infections. In humans, the thymus shrinks considerably with age, transitioning mostly to non-functional fatty tissue after puberty. At age 40, thymus production of T cells plummets to just a quarter of what it produces at age 8, dwindling to a mere 10% by age 656.
Rethinking T Cell Production in Older Adults
As a result, many researchers assumed older adults no longer required fresh T cells. “People often think T cell production is only vital when you’re young,” comments Jennifer Cowan, an immunologist at University College London. “This notion is clearly wrong.”
Three pivotal discoveries have reshaped this understanding. A 2023 study revealed that individuals who underwent thymus removal faced nearly three times the risk of death and double the chance of developing cancer five years post-surgery compared to those without such procedures7. Cowan noted its shocking implications, stating, “After reading that paper, you would think twice before having your thymus removed.”
In another marching tandem of studies, data from over 31,000 individuals indicated that a smaller thymus gland is linked to increased risks of mortality and cardiovascular diseases, such as cancer and heart failure3. Furthermore, a smaller thymus negatively impacted survival rates following cancer immunotherapy4.
While some experts caution that these studies illustrate correlation rather than causation, interest in thymus research continues to intensify. Yosuke Takahama, a developmental biologist at the National Cancer Institute in Bethesda, Maryland, stated, “Regrowth of the thymus could represent a transformative opportunity to restart our immune system, akin to rebooting a computer.”
Source: www.nature.com