Posted on 10 December 2021
Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.
Why is this research important: We have already succeeded in slowing down the ageing process – at least, in mice. We have known for many years now that blood transfusions from young mice reduce age-related deterioration in old mice. It is thought that blood plasma (blood, minus the blood cells) from young animals contains rejuvenating factors, while plasma from older animals contains signalling molecules associated with ageing. The theory is that by injecting an old mouse with young plasma, you introduce rejuvenating factors while simultaneously ‘diluting’ the factors that promote ageing (see this article for more the anti-ageing effects of plasma). Among other benefits, studies have found that young plasma infusions can improve memory performance in aged mice. Could young plasma infusions be used to reduce memory decline in ageing humans, perhaps slowing the progression of diseases such as Alzheimer’s?
As with any new treatment, the first stage after animal studies is to demonstrate safety in phase 1 clinical trials, which pave the way for larger trials focussing on disease outcomes.
What did the researchers do: In this study, researchers randomised nine 50-90 year-olds with mild to moderate Alzheimer’s disease to receive infusions of either blood plasma from young donors or an injection of saline solution. The plasma came from donors aged 18-30, and infusions occurred once a week for 4 weeks. The study was double-blind (meaning neither the people giving the infusions nor the recipients knew who received real plasma and who received saline solution). There was then a 6-week ‘washout’ period, after which the control group and the group receiving real plasma were swapped over. A separate group of 9 patients received only blood plasma once a week for 4 weeks. This part of the study was open-label, meaning that the patients knew that they were receiving real plasma.
Key takeaway(s) from this research: The primary aim of this study was to examine the safety of the treatment, and in that regard the results were encouraging. No one experienced serious side effects from the infusions, and there was no significant difference in side effects between the control group and the group that received the real treatment.
The study’s secondary aim was to investigate whether the treatment had any effect on the course of disease. This included conducting cognitive tests, questionnaires and brain scans at different stages of the study. Most of these tests did not show a significant improvement in the treatment groups, although caregivers did report significant improvements in one questionnaire.
Small studies such as this are not designed to prove whether or not a treatment is beneficial, nor do they detect uncommon side effects. Their main purpose is to pick up any severe adverse reactions before proceeding to larger trials, several of which are now underway.
One such trial (which began in September 2021) is looking specifically at the effects of blood transfusions from young donors who undertake exercise training, since exercise causes changes in blood composition and is known to protect against Alzheimer’s disease. This study will follow 60 participants who will receive 12 transfusions over the course of the first study year, and will be followed up after 2 years and 5 years.
Safety, Tolerability, and Feasibility of Young Plasma Infusion in the Plasma for Alzheimer Symptom Amelioration Study: http://jamanetwork.com/article.aspx?doi=10.1001/jamaneurol.2018.3288
Safety and Efficacy of Plasma Transfusion From Exercise-trained Donors in Patients With Early Alzheimer's Disease (ExPlas) (NCT05068830): https://clinicaltrials.gov/ct2/show/NCT05068830