Robust Mouse Rejuvenation — the first large-scale attempt to combine damage-repair interventions for additive lifespan extension. RMR1 complete (1,000 mice); RMR2 in design (2,000 mice, 8 interventions).
Why single interventions hit a ceiling — and how damage repair changes the calculus
For decades, longevity research focused on slowing metabolism — caloric restriction, rapamycin, metformin. These approaches delay damage accumulation but don't repair what's already there. When started in old age, the window of benefit narrows dramatically.
The LEV Foundation's Robust Mouse Rejuvenation (RMR) program takes a radically different approach: repair the damage itself. By combining interventions that each target a distinct category of age-related damage, the hypothesis is that additive (or synergistic) lifespan gains will break through the ceiling that no single therapy has ever breached.
Don't try to retune the impossibly complex metabolic network. Instead, repair the structural damage that accumulates as a side effect of normal metabolism.
Fixing one type of damage while ignoring others yields marginal gains. The neglected damage types still prove fatal on similar timelines.
Treatments begin at 18+ months (human equivalent ~60 years). This tests true rejuvenation, not just prevention — the most clinically relevant scenario.
1,000 C57BL/6J mice • 10 treatment groups × 2 sexes • Ichor Life Sciences, Syracuse NY • Feb 2023 – Feb 2025
The all-four combination outperformed rapamycin alone across most of the survival curve. Damage-repair interventions that appeared weak in isolation showed their value when combined with rapamycin.
Rapamycin appears to provide metabolic stability that lets mice tolerate and benefit from aggressive damage-repair therapies.
Synergy Confirmed
Rapamycin alone nearly matched the all-four combination, strongly driving mean lifespan extension. The damage-repair-only group (no rapamycin) initially tracked with top performers but then survival dropped precipitously to match controls.
This "drop-off" effect suggests single-dose damage repair has a limited window — damage re-accumulates. Future protocols require repeated dosing.
Rapamycin Dominated Key Lesson: Repeat Dosing
| Group | Rapamycin | Senolytic | mTERT | HSCT | N (per sex) | Control Type |
|---|---|---|---|---|---|---|
| Naive Control | — | — | — | — | 25 | No treatment |
| Mock Control | — | — | — | — | 25 | Sham procedures |
| Rapamycin Only | ✅ | — | — | — | 50 | Half mock / half naive |
| Senolytic Only | — | ✅ | — | — | 50 | Half mock / half naive |
| mTERT Only | — | — | ✅ | — | 50 | Half mock / half naive |
| HSCT Only | — | — | — | ✅ | 50 | Half mock / half naive |
| All Except Rapamycin | — | ✅ | ✅ | ✅ | 50 | — |
| All Except Senolytic | ✅ | — | ✅ | ✅ | 50 | — |
| All Except mTERT | ✅ | ✅ | — | ✅ | 50 | — |
| All Except HSCT | ✅ | ✅ | ✅ | — | 50 | — |
| All Four | ✅ | ✅ | ✅ | ✅ | 50 | — |
Injectable Gal-Nav vehicle proved unstable and toxic (peritonitis in pilot tests). Switched to oral gavage — but galactose conjugation likely degraded in gut, reducing efficacy.
Mobilization procedure (G-CSF + AMD3100) was physically stressful and difficult to scale. RMR2 switches to MSCs for easier repeat dosing.
Single-dose damage repair works temporarily — the female "drop-off" proves damage re-accumulates. RMR2 will use cyclic repeat dosing for all interventions.
Four interventions chosen for minimal mechanistic overlap and demonstrated mid-life efficacy
Mechanism: Inhibits mTOR signaling, mimicking caloric restriction. Delays cancer onset, improves immune function, enhances autophagy.
Delivery: 42ppm Eudragit S100 enteric-coated in chow (Purina 5LG6), continuous. Same encapsulation as ITP studies.
Prior evidence: Multiple ITP studies show 9–14% lifespan extension in males, 18–26% in females when started mid-life.
RMR1 result: Strongest single intervention — dominated female outcomes, provided metabolic stability for male combos.
Mechanism: Bcl-xL inhibitor conjugated with galactose moiety — activated by lysosomal β-galactosidase elevated in senescent cells. Clears SnCs while sparing normal cells.
Delivery: Originally injectable, switched to oral gavage after vehicle toxicity. Single administration.
Prior evidence: Navitoclax shown to clear SnCs in multiple tissue types. Galactose conjugation reduces platelet toxicity.
RMR1 result: Delivery compromised — galactose conjugation likely degraded in gut. No significant solo benefit, but may contribute to combo.
Mechanism: AAV vector delivers mouse telomerase reverse transcriptase gene. Extends telomeres, improves tissue function without increasing cancer risk.
Delivery: Intranasal AAV, monthly from 18 months. Less invasive than IV, shown equally effective by Church & Parrish (2022).
Prior evidence: Blasco lab: 41.4% lifespan increase in aged mice (AAV-mTERT, resumed at 32 months). Multiple replications.
RMR1 result: Contributed to combo — solo effect modest, but synergized with rapamycin in males.
Mechanism: Lineage-depleted bone marrow from young donors repopulates aged hematopoietic system. Restores immune function, reduces immunosenescence.
Delivery: Chemical mobilization (G-CSF + AMD3100) followed by young donor HSC infusion. Single administration.
Prior evidence: Young blood/stem cell studies show rejuvenation of multiple tissues. Immune reconstitution extends healthspan.
RMR1 result: Logistically challenging — mobilization stressful, donor scaling difficult. Replaced with MSCs in RMR2.
8 interventions • 2,000 mice • 20 treatment groups • Cyclic dosing • Rapamycin + running wheels as baseline
Target: Lipid peroxidation
Deuterated polyunsaturated fatty acids replace vulnerable membrane lipids with ROS-resistant versions. Oral delivery in chow. Safety established in human clinical trials.
NEW in RMR2 Oral Delivery
Target: Redox homeostasis + plasma dilution
Virgin albumin in saline restores ROS scavenging capacity (Cys34 thiol) and provides plasma dilution effects. Repeat dosing feasible.
NEW in RMR2
Target: Stem cell exhaustion
Mesenchymal stem cells replace RMR1's HSCs. MSCs give rise to bone, fat, muscle, cartilage, neurons, and more. Easier to expand ex vivo and repeat-dose.
UPGRADED from RMR1
Target: Epigenetic age
Temporary activation of Yamanaka factors (OSKM) erases age-associated epigenetic marks without altering cell identity. Cutting-edge delivery methods (mRNA/liposome/chemical).
NEW in RMR2 Highest Risk/Reward
Target: Fibrosis + inflammaging
IL-11 inhibition prevents/reverses cardiac, hepatic, and adipose fibrosis. Blocks ERK/MAPK and STAT3 pathways. Systemic anti-inflammatory effect. Recent mouse lifespan extension data.
NEW in RMR2
Target: Stem cell polarity / immunosenescence
Inhibits age-elevated Cdc42 activity in HSCs and other stem cells. Restores regenerative capacity, reduces systemic inflammation at its cellular root.
NEW in RMR2
Target: Senescent cells (via lipid metabolism)
Exploits SnC lipid vulnerabilities — elevated lysophosphatidylcholine and free arachidonic acid. LC-FACS blockade triggers selective senescent cell death via membrane disruption.
NEW in RMR2 Novel Senolytic Mechanism
Target: Multi-organ regeneration
The "bonding hormone" activates muscle satellite cells, promotes liver and bone regeneration, enhances neurogenesis, reduces neuroinflammation. Subcutaneous delivery, 0.5–2 mg/kg/day.
NEW in RMR2
| Feature | RMR1 | RMR2 | Rationale |
|---|---|---|---|
| Interventions | 4 | 8 | Target more damage categories simultaneously |
| Total mice | 1,000 | 2,000 | 20 treatment groups × 50/sex × 2 sexes |
| Rapamycin | 1 of 4 interventions | Universal baseline | Proven benefit; test new interventions on top |
| Exercise | None (sedentary) | Running wheels | No intervention maximally effective in obese mice |
| Dosing | Single administration | Cyclic repeat dosing | Single-dose window too narrow (female drop-off) |
| Stem cells | HSC transplant | MSC transplant | Broader tissue coverage, easier to scale/repeat |
| Senolytics | Gal-Navitoclax | LC-FACS inhibitor | New mechanism avoiding delivery issues |
| Monitoring | Manual | Smart cages | Continuous behavioral monitoring |
| Strain | C57BL/6J | C57BL/6J (or HET3) | HET3 better human model, used in ITP |
| Cost | ~$2.5M | ~$5M | Double scale + new interventions |
Explore hypothetical combination effects based on RMR1 data and published intervention studies
Adjust sliders to model hypothetical combination benefits. Based on published individual intervention data and RMR1 interaction effects. Illustrative model — not predictive.
Head-to-head comparison of all 12 interventions across RMR1 + RMR2
| Intervention | Study | Category | Delivery | Solo Evidence | Repeat Dose | Human Data | Risk |
|---|---|---|---|---|---|---|---|
| Rapamycin | RMR1+2 | mTOR | Oral (chow) | ⭐⭐⭐⭐⭐ | Continuous | Extensive | Low |
| Gal-Navitoclax | RMR1 | Senolytic | Oral gavage | ⭐⭐⭐ | Periodic | Phase I/II | Medium |
| AAV-mTERT | RMR1 | Telomerase | Intranasal | ⭐⭐⭐⭐ | Monthly | Preclinical | Medium |
| HSC Transplant | RMR1 | Stem Cell | IV + mobilization | ⭐⭐⭐ | Difficult | Clinical | High |
| D-PUFAs | RMR2 | Lipid protection | Oral (chow) | ⭐⭐⭐ | Continuous | Clinical trials | Low |
| Serum Albumin | RMR2 | Redox / Plasma | IV injection | ⭐⭐⭐ | Periodic | FDA-approved | Low |
| MSC Transplant | RMR2 | Stem Cell | IV injection | ⭐⭐⭐ | Yes (scalable) | Clinical trials | Low |
| Partial Reprogramming | RMR2 | Epigenetic | Various | ⭐⭐⭐ | Cyclic | Preclinical | High |
| Anti-IL-11 | RMR2 | Anti-inflammatory | Antibody / small mol | ⭐⭐⭐⭐ | Periodic | Preclinical | Medium |
| CASIN (Cdc42i) | RMR2 | Stem cell polarity | Injection | ⭐⭐⭐ | Periodic | Preclinical | Medium |
| LC-FACS Inhibitor | RMR2 | Senolytic (lipid) | TBD | ⭐⭐ | Periodic | Preclinical | Medium |
| Oxytocin | RMR2 | Regeneration | Subcutaneous | ⭐⭐⭐ | Daily | FDA-approved | Low |
From conception to combinatorial rejuvenation — and what comes next
Key publications, data sources, and further reading