Josh and all,
If you are referring to plasma exchanges as ‘transfusions’, I don’t think you are correct based on the evidence by two experimenters, Saul Villeda and Tony Wyss-Cory. That giving injections equivalent to 5% of total plasma volume in bi-weekly doses over the course of a month had significant rejuvenatory effect means that the factors causing rejuvenation, must have a half life long enough to allow an accumulation of factors in the blood sufficient to cause rejuvenation. (Other wise each injection causes a slight decrease in age phenotype which was cumulative – or else a single injection of 5% of total plasma volume should cause the total rejuvenation – and that isn’t likely). Add to that the observations by Michael Conboy that in vitro at least, the rejuvenation by young serum (and it was serum, so serum can substitute for plasma (as someone asked) occurred within twenty-four hours (and old stem cell exposed to ‘old’ plasma seemed to age immediately) So then, what constitutes the blood apart from the liver-supplied plasma proteins and the marrow supplied blood cells. Of course all the products that cells, tissues and organs secrete into the plasma. This defines the plasma and it appears from all studies, that these cell, tissue and organ-secreted products in the bloodstream ARE the age-determining molecules. So if a quorum of cells ‘converts’ to a younger age – those cells and the tissues and organs they are a part of secrete as would their younger versions, this would set up a newly stabilized age according to both quorum cellular age-phenotype and the age-determining molecules present in the plasma. My guess is that this will stably reset the body’s age-phenotype. In any case, the changes in brain age used to assess rejuvenation in the Villeda plasma injection experiments were assessed months after treatment so that treatment – way less than I propose to do with HPE – resulted in stable significant rejuvenation months after treatment. In that case how would HPE not work???