User:Violetriga/ongoing/Young blood transfusion

Young blood transfusion refers to transfusing blood specifically from a young animal into an older recipient with the intention of creating a medicinal benefit. While some studies declare that benefits have been observed in mice the lack of evidence and truly rigorous test environments means that the scientific community remains highly skeptical. Furthermore, contradictory evidence has been presented which suggests that young blood may have a reduced impact compared to other sources. The practice is seen as being a "current trend" in regenerative medicine and life extension while news reports relate it to various tales of immortality.

Trials on mice
Neuroscientist Tony Wyss-Coray leads a team of researchers at Stanford University investigating the use of young blood transfusions in mice. A study published by them in 2014 detailed the results of several tests including parabiosis in mice; as part of their investigations they sutured two mice of different ages together, with both animals sharing a circulatory system. The study concluded that the blood from the younger mouse contributed to improved synaptic plasticity in the older mouse and this consequently led to a perceived improvement in learning and memory. They also demonstrated that a transferral of a young mouse's blood plasma into an older mouse allowed the latter to significantly improve in certain tasks related to learning and memory. In 2017 a further study by Wyss-Coray and his team was published in Nature. This showed that older mice could benefit from blood transfused from human umbilical cords. They claim that this appears to "rejuvenate an old brain and make it work more like a younger one". In a 2017 article published in The Economist the effects in mice were labelled "spectacular" but the author made the point that the reason why this happened was not clear.

In 2018 a study by Dr. Saul Villeda, an assistant professor at the University of California, published new findings in journal Cell Reports. Villeda suggests that old brains may have "dormant plasticity" which can be utilised. "Young blood" has the ability to stimulate significant changes in DNA as regulated by the TET2 enzyme. Older brains have lower levels of TET2 with the hippocampus, the area of the brain associated with memory and learning, being particularly deficient. Villeda believes that DNA manipulation might in the future allow scientists to "make an organism younger again".

Human tests
A startup company named Ambrosia has been selling "young blood transfusions" for $8,000 since 2017 under the guise of running a clinical trial, to see if such transfusions lead to changes in the blood of recipients. Other, more advanced human trials are reported to be underway in China and Korea.

Evidence from two large studies in 2017 showed that the transfusion of blood from younger donors to older people was either no different from, or led to worse outcomes than, blood from older donors. Research on blood transfusion outcomes has been complicated by the lack of careful characterization of the transfusion products that have been used in clinical trials; studies had focused on how storage methods and duration might affect blood, but not on the differences among lots of blood themselves. Due to the current lack of evidence and the contradictory findings the scientific community currently views the practice as little more than snake oil.

A company, Alkahest, was spun out of Stanford based on that work, and as of 2017 was collaborating with European pharmaceutical company Grifols to create a blood plasma-based experimental biologic drug, which they propose to test on people with Alzheimer's.

Amy Maxmen writing for the MIT Technology Review warned of the dangers of such trials, noting that transfusions are generally considered safe but can have side effects including deadly infections.

Reporting
Young blood transfusions have been called a "current trend" in regenerative medicine, with significant Silicon Valley investment in "life extension". Jeff Bercovici wrote for Inc. that it is "a popular obsession" and that there are rumours of wealthy technology bosses "spending tens of thousands of dollars for the procedures and young-person-blood". The practice was referenced in a 2017 episode of comedy series Silicon Valley in which the boss of a technology company uses transfusions from a "blood boy" in an attempt to stay young and live longer.

News media have widely reported such practices using far-fetched analogies, likening the procedure to the Fountain of Youth and the elixir of life. Others have related it to stories of vampires.