Although negligible senescence in humans might be only a dream, the idea drives many efforts in anti-aging research. A multi-billion dollar cosmetics industry takes advantage of this field to quickly exploit any potential elixirs that have proven effective in laboratory conditions. Among the many so-called 'elixirs of youth' scrutinized by science, young blood might be the one that comes closest to deserve the label.
Researchers have been carrying out ambitious experiments on mice to observe if and how blood affects the process of aging. The findings seem quite interesting.
In a number of experiments carried out since the 1950s, elderly mice and young ones undergo a parabiotic procedure: their bodies are surgically joined by the skin to cause the blood of one animal to circulate through the body of the other. After the 'siamese' period, the mice are separated for the scientists to analyze the body effects caused by the experiment. It has been found that the organs of the older animal rejuvenate with the younger blood. The observed changes include improvements in brain blood flow, healing, smell, generation of new neurons, muscle strength, physical endurance, cognition and memory. Researchers have isolated a protein called GDF11 — located in blood plasma — as the likely ‘culprit’ of the impressive rejuvenating effects of young blood in mice.
More recently, Sakura Minami, a researcher at Alkahest — a company that develops blood-based therapies to improve health in old patients — questioned whether the plasma of young humans would do the same for old mice. She and her team injected samples of blood from human teenagers (18-year-old) into 12-month mice (rough equivalent to 50-year-old humans) twice a week over the course of three weeks. The Alkahest researchers found that young human blood also rejuvenated the old mice, with noticeable improvements to physical health and memory. The team also found evidence that the human blood promoted neurogenesis in the treated mice.
Since ancient times, it has been speculated that young blood might hold the key to increase longevity or slow down the signs of aging. However, not all researchers agree on whether young blood can actually help the elderly. It is known that gene expression of the GDF11 protein decreases with age, but more information is necessary to draw further conclusions. The company Alkahest has already started young blood tests in people with Alzheimer's. The results of this trial should shed light on whether the technique works for humans and whether we're much closer to a major breakthrough in anti-aging science than we thought.