This seems like a Thiel hit piece. Calling him obsessed is a bit much. How about all the people who eat right, are active, don't smoke, etc? We're all interested in longevity and health on some level. We know guys like Brin are deeper in the longevity hole, to the point of talking about sci-fi nuttiness like brain uploads and such. We also know that many celebrities do things like HGH injections.<p>Then quoting Gawker as a reliable source for an outrageous rumor with zero proof just tops it off. Clearly, Gawker is not going gently into that good night.<p>A non-hyserical article about possible longevity solutions championed by the SV wealthy here:<p><a href="http://www.newsweek.com/2015/03/13/silicon-valley-trying-make-humans-immortal-and-finding-some-success-311402.html" rel="nofollow">http://www.newsweek.com/2015/03/13/silicon-valley-trying-mak...</a><p>The article also explains the blood issue:<p>She found that a protein called GDF11, common in the blood of young mice but sparse in the systems of the older rodents, caused much of the old mice’s "reverse aging." In the bloodstream, GDF11 is responsible for keeping stem cells active; when GDF11 levels drop, as they do with age, stem cells (which are responsible for tissue renewal) falter, injuries heal more slowly and aging begins to take hold. But even in very elderly bodies with very little GDF11 inside them, those stem cells never go away—they merely become dormant as GDF11 levels drop. Injecting young blood, with its high levels of GDF11, into old mice seemed to restart those dormant stem cells, causing the old mice to "age in reverse" as they produced the healthy, vital tissues associated with youth. The work is “incredibly promising,” says Collins.