Repeated intermittent clearance of p21-highly-expressing cells extends lifespan and confers sustained benefits to health and physical function

A key challenge in aging research is to extend lifespan in tandem with slowing down functional decline so that the life with good health (healthspan) can be extended. Here, we show that clearance of a small number of cells, which highly express p21Cip1 (p21high), starting from 20 months improves cardiac and metabolic function, and extends both median and maximum lifespan in mice. Importantly, by assessing health and physical function of these mice monthly until death, we show that clearance of p21high cells improves physical function at all remaining stages of life, suggesting morbidity compression and healthspan extension. Mechanistically, p21high cells encompass several cell types, with a conserved pro-inflammatory signature. Clearance of p21high cells reduces inflammation, and rejuvenates transcriptomic signatures of various tissues to younger states. These findings demonstrate the feasibility of morbidity compression in mice, and indicate p21high cells as a therapeutic target for healthy aging. Overall design: p21-high cells were enriched by GFP using flow cytometry from stromal vascular fraction (SVF) of visceral fat from 5 25-30 months old p21-Cre transgenic mice. Cells from each donor were labelled with cell hashing antibodies (TotalSeq-A anti-mouse Hashtag, BioLegend) according to the manufacturer's protocol. Cells were then washed, and resuspended in 0.04% BSA/PBS. Labelled cells from each donor were pooled at equal proportions, then immediately sorted on a BD FACSAria Fusion cell sorter (BD Biosciences) for viable GFPhigh and non-GFPhigh cell populations. Cells from wildtype mice were used as GFP background for gating and sorting.