Thank you, in that old paper that I had read in details things are actually not so clear:
— there is a huge death following surgery, which in fact leads to a lack of precision when trying to mathematically rectify for such death in lifespan estimations
— the following is sufficient to explain(*) the results: parabiosis with a dead or almost dead animal has a negative influence on the other partner
So the design in itself had that limit to not being able to demonstrate a life extension unless it is a very strong life extension. With injections, that are minimally harmful and are one-way transfers, we could have demonstrated a life extension if there was a small-or-medium one, but that’s not what the results showed at least in our conditions. So, if I am not mistaken, it looks like twice a neutral result. But based on the numerous short term positive effects that were published, we can still hope in humans at least for Alzheimer’s.
By the way I have various indications in mice and rats (yes… would need to take the time to list articles) that IGF-1 inhibition/rapamycin/everolimus enhances neurogeneration in conditions of neurodegenerescence: I wouldn’t be surprised if everolimus could act against Alzheimer’s. Since Novartis is testing it to boost the response to flu vaccines, it looks like testing on Alzheimer’s could be quite feasible (?).
a) heterochronic young partners did not live long…possibly simply because their aged partner were dying. Indeed I had done some copy and paste of portions of the lifespan curves under paintbrush and it is (sadly) sufficient to explain the young survival curves
b) vice & versa, aged rats with young partners lived longer than aged rats with aged partners, because in the second case the partners were often dying. Again with some copy-paste in the picture (and based on the 280 days decay of the two cohorts of rats, and a little math) it is (sadly) sufficient to explain the aged curves.
De : J Pedro Magalhaes À : Edouard Debonneuil ; Gerontology Research Group Envoyé le : Samedi 24 janvier 2015 13h55Objet : Re: [GRG] Dr Dhahbi’s Parabiosis article
I too am not convinced yet that parabiosis is affecting aging, even
if young blood may improve tissue regeneration. As you say, it could
be like growth hormone in having short-term benefits but long-term
that said, there is an old paper suggesting parabiosis extends
lifespan in rats:http://ift.tt/1D3crNz