Young blood is indeed the source of youth
Last year, Saul Villeda from Stanford University and his colleagues demonstrated that transfusion of blood from young mice stimulates the growth of new cells in the brains of old animals. The results of this work were published in September 2011 in the journal Nature in the article The aging systemic milieu negatively regulates neurogenesis and cognitive function (a popular retelling can be read in the note "The blood of old people ages young brains, and young ones rejuvenate senile ones").
In order to study this phenomenon in more detail, the researchers analyzed its effect on gene expression in brain cells. To do this, they combined the circulatory systems of old and young animals, as in their previous work, and after their blood was well mixed, they analyzed samples of hippocampal tissue from old mice. Expression was changed by 200-300 genes, especially those whose proteins are involved in ensuring the plasticity of synapses underlying the mechanisms of learning and memory. Changes in the amount of a number of proteins involved in the process of nerve growth were also detected.
The infusion of young blood also increased the number and strength of interneuronal contacts in areas of the brain that are normally not capable of forming new cells. This did not happen when old animals were transfused with blood from animals of the same age.
To find out the effect of the demonstrated changes on cognitive function, scientists injected 12 old mice with 8 plasma injections of a young or old mouse within a month. Plasma was injected in order to exclude any influence of blood cells.
After that, the animals passed the standard memorization test, which consists in finding a platform hidden under water. Old mice that had previously been transfused with young plasma remembered the location of the platform much faster than animals that received infusions of old plasma.
To identify areas of the brain involved in the restoration of cognitive function, the researchers tested for the production of fear. Mice injected with young plasma were better able to remember the fear associated with tasks that activate the hippocampus. This indicates that young plasma has a special effect on this region of the brain.
However, the mechanism of this phenomenon remains a mystery. The authors failed to identify any factor responsible for the rejuvenating effects of young plasma. They are currently trying to identify possible candidates for this role, such as lipids and hormones.
The results of the work are presented at the annual congress of the Society of Neuroscience, held on October 12-17 in New Orleans, Louisiana.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru according to New Scientist: Young blood really is the key to youth.
18.10.2012