One thing to bear in mind is that most of the relevant studies are carried out in mice, and mouse telomere dynamics are significantly different from those of hu

One thing to bear in mind is that most of the relevant studies are carried out in mice, and mouse telomere dynamics are significantly different from those of humans. Telomerase gene therapies clearly slow aging and extend life in mice to some degree, but the actual mechanism involved is up for debate. We can argue that it has more to do with stem cell activity and influence on mitochondrial function for example than keeping cells out of senescence. My comfort level for telomerase therapies would be increased by running them in dogs or another longer lived mammal with telomere dynamics that are closer to those of humans and observing the results there. Of course this might well be beaten out by actually running them in humans if the BioViva / Sierra Sciences collaboration gets their medical center running in Fiji to offer the gene therapy at a reasonable cost some time in the next year or two.