Rapamycin and Nicotinamide Reverse Aging in Stem Cells From Elderly Donors
A short-term drug combo rejuvenates aged mesenchymal stem cells, boosting proliferation and reducing inflammatory markers in vitro.
Summary
As people age, their stem cells become senescent — they stop dividing, accumulate damage, and release inflammatory signals that undermine healing. This makes autologous cell therapies far less effective in older patients. Researchers at Shiraz University tested whether a brief treatment combining rapamycin (an mTOR inhibitor) and nicotinamide (a form of vitamin B3) could refresh aged mesenchymal stromal cells isolated from elderly donors. The combination improved cell proliferation, reduced markers of senescence like beta-galactosidase and the cell-cycle inhibitors p16 and p21, lowered reactive oxygen species, and reduced pro-inflammatory cytokines IL-1β and IL-6. The cells also showed improved ability to differentiate into bone tissue. These effects were linked to restored autophagy via the AMPK-mTOR pathway, suggesting the treatment clears cellular debris and resets aging programs in these cells.
Detailed Summary
One of the central challenges in regenerative medicine is that the patients who need cell therapies most — older adults — also have the least functional stem cells. Aging drives mesenchymal stromal cells (MSCs) into senescence, reducing their numbers, proliferative capacity, and therapeutic potency. Finding ways to rejuvenate these cells before transplantation could dramatically improve outcomes for elderly patients.
Researchers at Shiraz University of Medical Sciences cultured aged MSCs isolated from elderly donors in media supplemented with rapamycin (10 nM) and nicotinamide (5 mM) for one culture passage — a deliberately short, clinically translatable treatment window. They then assessed a comprehensive panel of senescence markers, inflammatory signals, differentiation potential, and key autophagy-related pathway activity.
The results were striking. Treated cells showed increased replicative capacity alongside reduced expression of the senescence markers p16 and p21. Beta-galactosidase activity — a hallmark of senescent cells — decreased, as did dysfunctional lysosomes and total cellular reactive oxygen species. Critically, the cells secreted lower levels of pro-inflammatory cytokines IL-1β and IL-6, indicating attenuation of the senescence-associated secretory phenotype (SASP) that drives chronic inflammation. Osteogenic differentiation capacity also improved. These effects were mechanistically tied to altered AMPK, mTORC1, and mTORC2 activity and enhanced autophagy — the cellular recycling process that clears damaged components and is frequently dysregulated in aged cells.
The implications are significant. If aged MSCs can be pharmacologically primed before autologous transplantation, elderly patients could receive higher-quality, more functional cells derived from their own bodies — avoiding immune rejection while improving therapeutic outcomes.
However, this is an in vitro study only, and the long-term stability of these rejuvenation effects has not been evaluated. Preclinical animal studies are needed before any clinical translation can be considered.
Key Findings
- Rapamycin + nicotinamide increased proliferation and reduced p16/p21 senescence markers in aged MSCs.
- The combination lowered pro-inflammatory cytokines IL-1β and IL-6, reducing the senescence-associated inflammatory secretome.
- Reactive oxygen species and dysfunctional lysosomes decreased, indicating improved cellular health.
- Osteogenic differentiation capacity was restored, suggesting broader functional rejuvenation.
- Effects were mechanistically linked to restored autophagy via AMPK-mTORC1/mTORC2 pathway modulation.
Methodology
Aged MSCs were isolated from elderly human donors and treated with rapamycin (10 nM) and nicotinamide (5 mM) for one culture passage. Researchers measured proliferation, senescence markers (p16, p21, β-galactosidase), ROS, SASP cytokines (IL-1β, IL-6), osteogenic differentiation, and AMPK-mTOR-autophagy pathway activity. This is an in vitro study with no animal or human trial component.
Study Limitations
This summary is based on the abstract only, as the full paper was not accessible. The study is purely in vitro, so findings may not translate directly to in vivo or clinical settings. Long-term stability of the observed senescence reversal was not assessed, and the study did not include functional transplantation experiments to confirm improved therapeutic outcomes.
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