For centuries, people have yearned for an elixir capable of restoring youth to their aging bodies and minds. It sounds like pure fantasy, but, in recent years, researchers have shown that the blood of young mice can exert a regenerative effect when transfused into older animals. Now, one of the NIH-funded teams that brought us those exciting findings has taken an early step toward extending them to humans.
In their latest work published in Nature, the researchers showed that blood plasma collected from the umbilical cords of newborn infants possesses some impressive rejuvenating effects . When the human plasma was infused into the bloodstream of old mice, it produced marked improvements in learning and memory. Additional experiments traced many of those cognitive benefits to a specific protein called TIMP2—an unexpected discovery that could pave the way for the development of brain-boosting drugs to slow the effects of aging.
Caption: Scanning electron microscopy image of T. mu in the mouse colon. Credit: Aleksey Chudnovskiy and Miriam Merad, Icahn School of Medicine at Mount Sinai
Recently, we humans have started to pay a lot more attention to the legions of bacteria that live on and in our bodies because of research that’s shown us the many important roles they play in everything from how we efficiently metabolize food to how well we fend off disease. And, as it turns out, bacteria may not be the only interior bugs with the power to influence our biology positively—a new study suggests that an entirely different kingdom of primarily single-celled microbes, called protists, may be in on the act.
In a study published in the journal Cell, an NIH-funded research team reports that it has identified a new protozoan, called Tritrichomonas musculis (T. mu), living inside the gut of laboratory mice. That sounds bad—but actually this little wriggler was potentially providing a positive benefit to the mice. Not only did T. mu appear to boost the animals’ immune systems, it spared them from the severe intestinal infection that typically occurs after eating food contaminated with toxic Salmonella bacteria. While it’s not yet clear if protists exist that can produce similar beneficial effects in humans, there is evidence that a close relative of T. mu frequently resides in the intestines of people around the world.
We all know that exercise is important for a strong and healthy body. Less appreciated is that exercise seems also to be important for a strong and healthy mind, boosting memory and learning, while possibly delaying age-related cognitive decline . How is this so? Researchers have assembled a growing body of evidence that suggests skeletal muscle cells secrete proteins and other factors into the blood during exercise that have a regenerative effect on the brain.
Now, an NIH-supported study has identified a new biochemical candidate to help explore the muscle-brain connection: a protein secreted by skeletal muscle cells called cathepsin B. The study found that levels of this protein rise in the blood of people who exercise regularly, in this case running on a treadmill. In mice, brain cells treated with the protein also exhibited molecular changes associated with the production of new neurons. Interestingly, the researchers found that the memory boost normally provided by exercise is diminished in mice unable to produce cathepsin B.
Tony Wyss-Coray / Credit: Stanford School of Medicine
Basic scientists have long studied aging by looking inside of cells. While this research has produced many important leads, they are now starting to look outside the cell for the wealth of biochemical clues contained in the bloodstream.
To introduce you to this exciting frontier in aging research, this blog highlighted a while back the work of Tony Wyss-Coray at Stanford School of Medicine, Palo Alto, CA. He and a colleague had just received a 2013 NIH Director’s Transformative Research Award to explore the effects of exercise on the brains of mice. Their work, in fact, produced one of Science Magazine’s Breakthrough Discoveries of 2014. Their team showed that by fusing the circulatory systems of old and young mice to create a shared blood supply, the young blood triggered new muscle and neural connections in the older mice, while also improving their memories.
As fascinating as this theoretical Fountain of Youth was, Wyss-Coray recognized a critical limitation. He had no way of knowing how factors secreted by the young mouse could actually cross the blood-brain barrier and rejuvenate neurons. To solve this unknown, Wyss-Coray recently received a 2015 NIH Director’s Pioneer Award to build a potentially game-changing tool to track the aging process in mice.
The average life expectancy in the United States currently is about 79 . And, unsurprisingly, more than two-thirds of Americans say they’d like to live another 10 to 20 years longer .
One possible route to a longer life is to cut calories drastically. Not much fun perhaps, but there’s evidence it works in yeast, worms, and mice—but probably not in monkeys . The potential life-extending strategy that I’d like to tell you about today focuses on the drug rapamycin, which blocks the activity of a protein called “target of rapamycin,” or TOR. Recently, a team here at NIH discovered that—at least in mice—reducing production of this protein through genetic engineering can add about 20% to the lifespan . Continue reading →