I understand your concerns – sorry I went off in that direction – I don’t really care very much about nephrons. My belief is that the blood plasma’s contents are very relevant to aging itself. I believe (based on evidence) that is how a cell ‘knows’ it’s age-phenotype. I believe the emphasis on aging cells is wrong. I would very much like it if all organs had the potential for rejuvenation, but sufficiently many do to make HPE the best bet for life extension at present. If I didn’t think that, I wouldn’t be wasting our time.