This is an interesting paper. I would be almost inclined to think that the life extension effect has to do with the link between telomerase and mitochondrial damage, but that's very speculative at this point. For all we know, the treatment of mice might have led to accidental calorie restriction and extended life span by that method: "Telomeres become shorter after each cell division, which is one of the mechanisms of gradual ageing. Telomerase is the reverse transcriptase responsible for the extension of telomere length. It is well known that activation of telomerase in the most types of organism's cells is not enough for telomere length stabilization. The reason may be in the telomere 'caps', which cover telomere ends from telomerase action. This experiment shows that telomeres were elongated by the combination of hypoxia activated telomerase and a newly developed pharmacological method removing the telomere cap ... Rats from the control group died at the age 1 year 7 month - 1 year 8 month, which is typical for the Wistar rats from our sub-line. Rats from the experimental group died at the age 2 year 4 month."

Link: http://www.ncbi.nlm.nih.gov/pubmed/19145831