There were also some signs suggesting improvements in participants' conditions.

Above – Sharon Sha presented findings Nov. 4 from a small clinical trial that found administering blood plasma from young donors to people with mild to moderate Alzheimer's disease was safe. Paul Sakuma

Finding of safety wasn't surprising, given that blood-plasma infusions have long been in widespread use for other indications and are considered extremely safe. More surprising, she said, were hints of recipients' improvement on tests of functional ability: the capacity to perform basic tasks essential to independent daily life, such as remembering to take medications and being able to pay bills and prepare one's own meals.

The PLASMA trial was designed to test a hypothesis advanced by Tony Wyss-Coray, PhD, Stanford professor of neurology and neurological sciences and a senior research career scientist at the Veterans Affairs Palo Alto Health Care System, whose research has shown that factors in the blood of young mice can rejuvenate the brain tissue and improve cognitive performance in old mice.