according to the paper summary (https://www.cell.com/cell/abstract/S0092-8674(25)00571-9) it slows, not reverse aging marker:

Aging is characterized by a deterioration of stem cell function, but the feasibility of replenishing these cells to counteract aging remains poorly defined. Our study addresses this gap by developing senescence (seno)-resistant human mesenchymal progenitor cells (SRCs), genetically fortified to enhance cellular resilience. In a 44-week trial, we intravenously delivered SRCs to aged macaques, noting a systemic reduction in aging indicators, such as cellular senescence, chronic inflammation, and tissue degeneration, without any detected adverse effects. Notably, SRC treatment enhanced brain architecture and cognitive function and alleviated the reproductive system decline. The restorative effects of SRCs are partly attributed to their exosomes, which combat cellular senescence. This study provides initial evidence that genetically modified human mesenchymal progenitors can slow primate aging, highlighting the therapeutic potential of regenerative approaches in combating age-related health decline.