Young blood transfusion

Experiments beginning in the 1950s in the Cornell University lab of Clive McCay on pairs of old and young rodents placed into parabiosis provided some evidence, albeit limited and "largely anecdotal", that the circulation of blood from young mice increased both the longevity and the tissue function of old mice.[4] After decades in which relatively little work on parabiosis in aging was done, the work was revived by researchers at Stanford University and the University of California at Berkeley.[4][5] Parabiosis experiments are difficult to generalize, as the circulatory systems of the mice are fully joined and it is unclear whether the benefits come from the sharing of blood or the older mouse's access to the younger mouse's organs.[1] A study conducted at UC Berkeley found that when delivered alone, blood from older mice was more inhibitory to the regenerative capacities of younger mice than blood from younger mice was beneficial to older ones, and that the benefit of young blood in older mice was less than had been observed when older mice were subjected to parabiosis.[6][7]

In experiments like this, researchers found that some of the parabiosed died quickly (11 out of 69 in one experiment) for reasons the scientists could not explain, but described as possibly some form of immune rejection;[4][1] most such cases were the young parabiont.[4] Amy Wagers, a researcher who coauthored several mouse studies on young blood transfusion, has said that her papers do not provide a scientific basis for some of the existing human trials.[2]

A review of studies on donor age for whole blood transfusions reported that blood from donors under the age of 20 years, when compared to donors aged 20–60 years, resulted in a modestly higher risk of death in the recipients.[8] However, other studies have found no effect of age.[9][10] 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.[11]

In February 2019 the FDA warned about companies offering young blood transfusions stating:

"simply put, we’re concerned that some patients are being preyed upon by unscrupulous actors touting treatments of plasma from young donors as cures and remedies. Such treatments have no proven clinical benefits for the uses for which these clinics are advertising them and are potentially harmful. There are reports of bad actors charging thousands of dollars for infusions that are unproven and not guided by evidence from adequate and well-controlled trials. The promotion of plasma for these unproven purposes could also discourage patients suffering from serious or intractable illnesses from receiving safe and effective treatments that may be available to them."[3][12]

• Makin, Simon (21 April 2017). "Fountain of Youth? Young Blood Infusions "Rejuvenate" Old Mice". Scientific American. Retrieved 5 May 2018.