But as we age, the immune system becomes less effective. The process even has its own name - immunosenescence.
The good news is that scientists believe they've found an answer to this decline -- a development that could help us live a lot longer.
Thymic Involution
Weighing in at roughly an ounce, the thymus is a tiny gland located between the top of the lungs – but it packs a powerful immune punch.It produces progenitor cells that mature into T-cells (meaning thymus-derived cells) that defend the body from pathogens and more. Trouble is, it starts to shrink by the time we’re twelve months old and continues to do so until - in our 70s - it hardly functions at all, having turned into fatty tissue.
This is not happy news. . .
The process is called thymic involution and is believed to be linked to an increased susceptibility to infections, cancer and autoimmune disease.
Many scientists see the reversal of thymic involution as a key strategy for sustaining good health in old age and adding years to our lives. Several research groups are looking for ways to do that.
A Key Growth Factor
One method that looks promising is by boosting a hormone called fibroblast growth factor (FGF) 21.When levels of FGF21 are elevated in old mice, the thymus is protected from fatty degeneration and the gland is able to produce new T cells.
Even more interesting was the effect on lifespan. It was extended by an astounding 40%. Vishwa Deep Dixit, Ph.D., professor of comparative medicine and immunobiology at Yale School of Medicine, led the research. He speculates that "If the average lifespan is 80 years in humans, and if FGF21's effects from mice translate into humans, FGF21 may add approximately 30 years to life."
More than likely, nothing that dramatic will happen soon just because of this one factor, but smaller gains seem realistic.
Master Regulator FOXN1
Five years ago. scientists at the University of Edinburgh, Scotland, regenerated the thymus in old mice. This was the first time a living thymus had been rebuilt. The structure of the gland was similar to that of young mice, with increased numbers of T cells.The scientists achieved this by targeting and boosting FOXN1, a protein that's considered the master regulator of thymic growth and which decreases rapidly with aging.
A consortium of nine research teams from seven countries has been put together to develop this work in a project called ThymiStem.
The Growth Hormone Approach
Rodent and human studies have shown human growth hormone (HGH) is capable of inducing thymus regeneration, so the research of Intervene Immune, a biotech company, is focused on this. They also use the adrenal hormone DHEA.The company’s founder, Dr. Greg Fahy, a prominent scientist, first proved the therapy on himself with both a rise in T cells and thymus regrowth.
Dr. Fahy then led a human trial that involved top scientific collaborators from UCLA and Stanford. It included nine men aged 50 to 65 who were given hormone therapy for a year.
The trial has not yet been published, but preliminary results suggest it is safe. Side effects of using hormones can include raised insulin levels, an increased cancer risk and the promotion of systemic inflammation. None of these effects were apparent. In fact, the participants saw biomarkers of cancer risk and inflammation go down.
They also experienced structural and functional regeneration of the thymus.
Anecdotal reports among the participants included broad systemic benefits: greater strength, better mood, improved cognition -- even hair going from gray to dark.
I could dig it. I hope this exciting therapy is soon available to all.
