In the study, published April 19 in the journal Nature, researchers from Stanford University found that plasma from blood in human umbilical cords had a stimulatory effect on the brains of mice. But their performance perked right up after they got shots of plasma derived from human umbilical cord blood, obtained from consenting moms undergoing caesarian sections.
A new study hints that young blood may harbor clues to a "fountain of youth" for older brains. It's unclear, she says, whether a protein in plasma could actually make its way from a mouse's bloodstream into its brain, or that, once there, it could actually impact brain function.
Next, they injected more aging mice with human plasma and tested the animals' ability to remember things. He further said that this study suggests that a factor in human umbilical cord blood could enter the brain and fix some of the processes that are needed for generating new memories, according to The Telegraph.
Like in humans, cognitive function deterioration and hippocampus degeneration were observed in older mice at the beginning of the study.
"It's remarkable something in your blood can influence the way you think", said the study's senior author, Dr Tony Wyss-Coray, PhD, professor of neurology and neurological sciences at Stanford. As part of his work, he and fellow neuroscientist Joseph Castellano, also at Stanford, have started testing plasma collected from the umbilical cords of newborn babies.
The researchers suspected that these age-associated changes might have an effect on the hippocampus, the brain structure critical for "converting experiences into long-term memories" in both humans and mice.
For largely unknown reasons, the hippocampus is especially vulnerable to normal aging, said Wyss-Coray. With advancing age, it degenerates, loses nerve cells and shrinks. "They did not learn better".
When they removed TIMP2 from cord plasma and injected the plasma into mice, they didn't observe any improvement on the memory tests.
The team then analyzed protein changes in human umbilical cord, young adult, and elderly adult plasma, as well as in plasma from mice of different ages, identifying TIMP2 as a candidate plasticity-promoting factor.
The mice with umbilical cord blood performed the best, followed by those who got the blood from young people. Plasma from young adults had less of an impact.
Immune-deficient mice were used in the study to prevent the mice experiencing negative immune reactions from the repeated injections of human plasma. These mice were aged equivalent to 70 human years. And when they injected plasma containing TIMP2 into elderly mice, they again observed improvement in memory and learning tasks.
Decades ago in somewhat grisly experiments, researchers found that sewing together the circulatory systems of an old and young mouse so that they shared the same blood supply rejuvenated the old animals.
New born neurons in the transgenic mouse hippocampus (dentate gyrus) labeled with green fluorescent marker. This is a behavior that is usually forgotten in old age.
Older mice that were given umbilical cord plasma deprived of TIMP2 displayed no valuable change in learning and memory.
Following the TIMP2 administration, scientists discovered that the mice's performance in memory tasks was enhanced vis-à-vis their performance in the same tasks prior to getting the tissue inhibitor.
He goes on to say that the new study by Castellano and his colleagues is an excellent starting point.
"Although the treatments tested here boosted some aspects of learning and memory in mice, we don't know how relevant the findings might be to people", said David Reynolds, chief scientific officer at Alzheimer's Research UK. "A lot of individual factors in blood can improve function".