Researchers from Stanford University School of Medicine have found that giving blood plasma infusions taken from young donors to people with mild-to-moderate Alzheimer’s disease is not only safe and feasible, but may improve recipients’ functional ability and capacity to perform daily tasks.
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The findings come from an early-phase clinical trial called the PLASMA trial – short for Plasma for Alzheimer's Symptom Amelioration, which was designed to test a hypothesis put forward by Tony Wyss-Coray, a professor of neurology from Stanford. Wyss-Coray had conducted research showing that factors in the blood of young mice could rejuvenate the brain tissue of old mice and enhance their cognitive performance.
The trial’s principal investigator, Sharon Sha, says it was not surprising to find that administering blood-plasma infusions was safe, given that this is has already been in widespread use for a long time for other indications. However, she was surprised to find signs that the recipients had improved functional ability, which is the capacity to perform basic day-to-day tasks such as taking medication, paying bills or preparing meals. Sha also notes that the study only involved 18 participants; further studies involving larger cohorts would be needed before any conclusions about efficacy could be drawn.
This current, smaller trial involved two stages. During the first stage, nine people with mild-to-moderate Alzheimer’s were given four-week infusions of either blood plasma taken from people aged 18 to 30 or saline solution, which served as a placebo.
Neither the recipients or those giving the infusions were aware of which of the two infusions the recipients were being given. Following a six-week “washout” period, the regimens were swapped and those who had previously received the blood plasma, were given four-week infusions of placebo and vice versa.
Before and after both four-week infusion periods, participants and care-givers completed tests and questionnaires designed to ascertain cognition, mood and functional ability amongst the participants.
The second stage involved nine further participants who all received the plasma from young donors, with both the participants and the caregivers being aware of this. These individuals were given the same tests and questionnaires to complete as the first group.
Once all participants had been treated, the test results were analysed. The researchers found no significant changes in the participants’ mood or cognitive ability, as determined by the ability to remember items in a list or recall recent events, for example. However, two of three tests of functional ability, showed significant improvement amongst those from the first stage of the study.
Sha says she was surprised to find this as the trials was not powered to demonstrate efficacy: "Our enthusiasm concerning these findings needs to be tempered by the fact that this was a small trial. But these results certainly warrant further study."