(looks as though stored blood cannot be used--must be the chemical(s) used for preservation reduces/changes factors?)

https://student.societyforscience.or...d-elixir-youth

A neuroscientist at the Stanford University School of Medicine in Palo Alto, Calif, Wyss-Coray worked on one of the new blood studies. His team published its findings May 4 in Nature Medicine.

Two others studies published that same day, but in the journal Science, report similar results. All found that old mice get better at learning and remembering when they have young blood circulating in their brains.

The Science studies linked those mental and health benefits to one particular ingredient found in the blood of young mice.

Young blood confers benefits to the heart, liver and pancreas, earlier studies showed. The new ones found that an elderly mouse brain also can improve and become sharper through this simple treatment. That suggests the mental problems that many people experience when they grow older may be preventable, Lee Rubin told Science News. He's a neuroscientist at Harvard University in Cambridge, Mass. He also worked on one of the studies just reported in Science.

How young blood may help
The experiments carried out by Wyss-Coray and his colleagues were simple. They connected blood vessels from old mice to young mice and let the blood mix. The blended blood flowed through both animals. In 2011, these researchers reported that this mixing harmed the brains of young mice getting the geezer’s blood. But the researchers now find that the same is not when the treatment is reversed. Old animals benefitted from mixing young blood into their veins.

For a mouse, “elderly” means 18 months old. That’s equivalent to a person between 55 and 70 years old. The young mice were only three months old, which corresponds to a human that’s 20 to 30 years old.

The function of nerve cells, or neurons, also improved in the old mice receiving the mixed blood. Neurons are brain cells that communicate with each other. The neurons of old mice pumping young blood appeared to grow new places where they could connect with other neurons. This growth of new connection spots is something that typically occurs in young brains. More connections should help a brain work better.