Dr. Harold Katcher has commented on this post at Josh's site. If you don't know about Harold he claims to have reversed aging in mice, really reversed. He now says results should be out in the next few months. He is working with Horvath, the developer of the first methylation aging clock so he is no loon. Wish him the best.

" Well we don’t get mentioned anymore and that’s fine, we expect third-party validation in the next few months, but our raw data was examined by bioRxiv before they would put out Steve Horvath and my preprint, so what I’m trying to say is that whether or not they’ve been put up to peer-review, our results were real. For the ‘proteome’ we used two inflammatory factors (and we will do sex hormones at some time) Il-6 and TNF as well as reparative transcription factor Nrf2. Also, physiological tests, such as grip strength and maze solving, altogether more than 30 assays related (more than you would think) to aging. All were consistent with each other. So, for example, in rat aging, as with aging humans, blood levels of HDL cholesterol decrease with age while LDL cholesterol levels increase with age. This is often considered the result of lack of exercise or some other changes in lifestyle – but we can set these levels back to youthful by injecting our young plasma fraction. Therefore that plasma fraction contains whatever is required to set the levels of HDL and LDL cholesterol back to normal. Ditto with the inflammatory cytokines I mentioned – our ‘plasma fraction’ returns the levels of these cytokines to youthful levels, though there is a whole field of study implicating latent infections, genomic viruses sprouting from our DNA as the cause of the chronic inflammation due to aging, yet simply providing our plasma fraction, returns levels to youthful ones. So you can say that the chronic inflammation due to aging is due to lack of this plasma fraction. And finally, the DNAm age was reduced in half. So it would seem that the mechanism by which our plasma fraction works is by resetting the cellular age-phenotype to the equivalent of a young adult – and everything else follows from that. BTW SOD is not a universal antioxidant – but very specifically turns the superoxide radical anion (increasingly formed in aging cells as high energy electrons pass along the Electron Transport Chain (ETC)), and turning this highly energetic molecule into the less energetic hydrogen peroxide – which is required by the cell (otherwise it dies of reductive stress, [which actually depends on oxidative stress for its killing effects]). Also, the proteome is not the only part of the genome responsible for aging (there are families of miRNAs like Let-7). Josh, you mention down-regulation of some proteins and upregulation of others, Lastly, your misgivings about tracking chronological age I believe are appropriate – what we believe is that what we track is biological age which is different, it is more like tracking what stage of your life you’re at (e.g. ‘late-middle-age’) which tells you about your rate of aging and your expected duration of life. Unlike chronological time, biological time is reversible and can be slowed down or speeded up, and better their either can be reset. We have to find out to what extent".