Longevity & Aging Newsletter
Issue #33April 20, 20267 studies

Weekly rapamycin actually hurt exercise gains in older adults

This week brought surprising results from aging research: a longevity drug backfired, your mouth bacteria can predict how fast you're aging, and scientists mapped the cellular cleanup systems that keep us healthy.

πŸƒ Rapamycin Backfires: Weekly Doses Hurt Exercise Performance

  • 40 adults aged 65-85 took either rapamycin (6mg weekly) or placebo while doing home exercises for 13 weeks

  • The rapamycin group performed 2-3 fewer chair-stand repetitions than placebo group and had 99 adverse events vs 63 in placebo

  • One person in the rapamycin group developed pneumonia, possibly drug-related

Why it matters: Rapamycin is widely studied as an anti-aging drug, but this suggests weekly dosing may actually interfere with the muscle-building benefits of exercise in older adults. The "cycling hypothesis" that alternating mTOR activation and inhibition enhances exercise didn't pan out in humans.

πŸ₯ˆ Top 2% journal πŸ”— Journal of cachexia, sarcopenia and muscle Randomized Controlled Trial πŸ—“οΈ Apr 15

Key Findings

🦠 Your Mouth Microbes Predict Biological Age

  • Scientists analyzed oral bacteria from 4,675 people and built a machine learning model that predicts chronological age

  • People whose predicted age was higher than actual age had 5% higher mortality risk and 5% higher frailty risk

  • The "aging acceleration score" also correlated with kidney problems and improved cancer and heart attack risk prediction

πŸ’‘ A simple oral swab could become a non-invasive way to identify people at higher risk for age-related diseases.
πŸ₯ˆ Top 2% journal πŸ”— Nature communications Journal Article πŸ—“οΈ Apr 17

πŸ”‹ Exercise Rewires Cellular Cleanup for Anti-Aging

  • Different types of exercise (endurance, HIIT, resistance) each trigger specific pathways that maintain mitochondrial quality control

  • These pathways coordinate mitochondrial renewal, protein maintenance, and removal of damaged cellular components

  • The review shows exercise systematically remodels cellular recycling through AMPK, SIRT1, and p38 MAPK signaling

πŸ’‘ Exercise may work as an anti-aging intervention by activating the cell's quality control systems that naturally decline with age.
πŸŽ–οΈ Top 10% journal πŸ”— Frontiers in cell and developmental biology Review πŸ—“οΈ Apr 16

🧠 Protein Degrader Clears Alzheimer's Tau in Human Neurons

  • A engineered antibody-based molecule called 1D9-LIRΞ”TP53INP2 successfully cleared tau protein in neurons from frontotemporal dementia patients

  • The molecule works by recruiting cellular recycling machinery (autophagy) to degrade tau aggregates

  • In mice with tau mutations, the treatment crossed the blood-brain barrier and improved motor function

πŸ’‘ This autophagy-targeting approach could offer a new strategy for treating tau-related dementias where protein clumps damage brain cells.
πŸ₯‡ Top 1% journal πŸ”— Science translational medicine Journal Article πŸ—“οΈ Apr 15

⚑ Iron Overload Blocks Cellular Cleanup, Causing Bone Loss

  • Excess iron in bone marrow stem cells prevents mitophagy (removal of damaged mitochondria) by blocking PINK1 signaling

  • This leads to mitochondrial dysfunction, cellular aging, and impaired bone formation

  • Activating mitophagy either with drugs or genetic manipulation restored bone health and reduced cellular aging

πŸ’‘ Iron accumulation may contribute to age-related bone loss by disrupting the cellular systems that maintain healthy mitochondria.
πŸ₯ˆ Top 2% journal πŸ”— Redox biology Journal Article πŸ—“οΈ Apr 16

🍽️ Healthy Diet Slows Epigenetic Aging Over Decades

  • 1,039 people tracked for 17-32 years showed that better diet quality (Mediterranean, Baltic Sea, healthy eating indices) was linked to slower epigenetic aging

  • The effect was strongest in people with low physical activity - good diet seemed especially protective when exercise was lacking

  • All diet indices showed consistent associations with decelerated biological aging across multiple epigenetic clocks

πŸ’‘ Long-term healthy eating patterns may be particularly crucial for biological aging in people who don't exercise much.
πŸ”— The Journal of nutrition Journal Article πŸ—“οΈ Apr 17

πŸ”¬ Blocking Ghrelin Receptor Improves Muscle Function in Aging

  • Male mice lacking the ghrelin receptor (or treated with a blocking drug) showed improved muscle endurance and strength during aging without affecting lifespan

  • The treatment increased markers of mitochondrial health (PGC-1Ξ±) and cellular cleanup (mitophagy) in muscle

  • Pharmacological blocking also reduced body weight and fat mass beyond what genetic deletion achieved

πŸ’‘ The ghrelin receptor emerges as a potential drug target for age-related muscle weakness, working through mitochondrial pathways.
πŸ₯‰ Top 5% journal πŸ”— Aging cell Journal Article πŸ—“οΈ Apr 16

Implications

This week's research reveals the complexity of aging interventions - while rapamycin disappointed in exercise contexts, multiple studies point to cellular quality control systems (autophagy, mitophagy, mitochondrial maintenance) as key targets. The oral microbiome and dietary patterns emerge as practical biomarkers and interventions for biological aging.

Studies in this issue

Primary sources used for this newsletter.

  1. Exercise and Weekly Sirolimus (Rapamycin) Use in Older Adults: A Randomized, Double-Blind, Placebo-Controlled Trial
    main storyJournal of cachexia, sarcopenia and muscle2026-04-15PMID 41985884
  2. Mouth bacteria patterns linked to biological age and health
    key findingNature communications2026-04-17PMID 41997961
  3. How FTMT reduces cell cleanup to connect iron buildup with osteoporosis
    key findingRedox biology2026-04-16PMID 41990575
  4. How exercise-related changes in cell energy factories affect aging
    key findingFrontiers in cell and developmental biology2026-04-16PMID 41988385
  5. Blocking Ghrelin Receptors May Improve Muscle Function in Aging Male Mice
    key findingAging cell2026-04-16PMID 41986945
  6. How Diet and Exercise Are Linked to Biological Aging in Working-Age Finns
    key findingThe Journal of nutrition2026-04-17PMID 41997491
  7. A specialized antibody removes tau protein in patient neurons and improves movement in mice with tau disease
    key findingScience translational medicine2026-04-15PMID 41984931

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