Issue #55September 21, 20267 studies

A vascular enzyme quietly drains NAD+ from your whole body as you age

Aging research had a big week — and the throughline is surprisingly consistent: cells stop cleaning up after themselves, and the consequences ripple outward.

From heart tissue to blood vessels to the brain, the same themes kept surfacing: NAD+ depletion, senescent cells accumulating where they shouldn't, and the body's quality-control systems quietly failing.

The enzyme in your blood vessels that's aging your whole body 🩸

Researchers identified a pathway in aging vascular endothelial cells — the cells lining blood vessels — where a protein called AEP cleaves NAMPT, the enzyme your body needs to make NAD+. Less NAMPT means less NAD+, system-wide.
In mice engineered to overexpress this pathway specifically in endothelial cells, vascular aging accelerated and lifespan shortened. Blocking AEP genetically — or making NAMPT resistant to cleavage — reversed those effects and extended lifespan.
Pharmacologically, an AEP inhibitor called CP#11A outperformed NMN supplementation at slowing vascular decline in aging mice. The implication: fixing the enzyme that destroys NAD+ precursors may matter more than just adding more precursors.

Why it matters: This reframes vascular aging not as passive wear-and-tear but as an active, enzyme-driven process — one with a specific molecular target.

🥈 Top 2% journal 🔗 Science advances Journal Article 🗓️ Sep 16

Key Findings

Sex-specific aging clocks reveal what pooled models miss 🧬

Researchers built 38 biological aging clocks trained separately on female and male data across 15 organ systems, then tested them in longitudinal survival analyses and a preclinical Alzheimer's trial.
Female and male clocks showed distinct genetic associations, different organ-level aging patterns, and divergent links to cardiometabolic and cognitive outcomes — differences that sex-pooled models obscured.

💡 Aging is not sex-neutral; clocks trained that way may be missing the point.

🔗 Nature medicine Journal Article 🗓️ Sep 16

Clearing senescent cells eases ALS symptoms in mice 🧠

In mice carrying a TDP-43 mutation linked to ALS, senescence markers appeared in the motor cortex and spinal cord early — before significant functional decline.
Treatment with dasatinib and quercetin (a senolytic drug combination) improved motor behavior, reduced axonal damage measured by a blood biomarker, and preserved neuron counts in the motor cortex. Microglia showed reduced TDP-43 burden after treatment.

💡 Senescent cells may be an early and targetable feature of ALS, not just a bystander.

🔗 Neurobiology of disease Journal Article 🗓️ Sep 18

GLP-1 drugs may slow epigenetic aging — not just weight 💊

A review synthesizing recent trial data notes that semaglutide reduced all-cause mortality by 19% in people with obesity but without diabetes in the SELECT trial — an effect larger than weight loss alone would predict.
A 2025 randomized study reported significant deceleration of three validated DNA methylation aging clocks over 32 weeks of semaglutide therapy, raising the possibility that GLP-1 drugs act on aging biology directly.

💡 GLP-1 drugs' mortality benefits may partly reflect geroprotection, not just metabolic control.

🔗 Experimental gerontology Review 🗓️ Sep 14

Senescent heart cells drive age-related cardiac stiffening 🫀

In mice aged 12 to 18 months, clearing p16-positive (senescent) cells reduced left ventricular wall thickening and normalized diastolic dysfunction — both hallmarks of age-related cardiac remodeling.
Flow cytometry and imaging pointed to senescent fibroblasts as the primary cleared population. Exposing healthy cardiomyocytes to secretions from senescent fibroblasts triggered hypertrophy markers, suggesting the damage spreads through chemical signaling.

💡 Senescent fibroblasts appear to drive cardiac aging partly by signaling to neighboring muscle cells.

🔗 Experimental physiology Journal Article 🗓️ Sep 14

A brain-to-spleen signal makes women more cognitively vulnerable at midlife 🔬

In female mice and human brain and spleen tissue, senescence-associated features rose preferentially in middle age. An X-linked protein called RBMX drove increased production of a small RNA (miR-10a-5p) in the spleen, which then appeared to influence the brain.
Blocking this small RNA in mouse models improved mitochondrial function, reduced cellular senescence, and enhanced memory. In neurons derived from Alzheimer's patients, inhibiting the same RNA reduced disease-associated changes.

💡 A peripheral-to-brain signaling axis may help explain women's heightened midlife cognitive vulnerability.

🔗 Neuron Journal Article 🗓️ Sep 18

Lower NAD+ in blood is linked to frailty in older adults 📊

Among 529 community-dwelling adults aged 65 and older in Japan, those with frailty had measurably lower whole-blood NAD+ concentrations than those without.
Each one-unit increase in NAD+ concentration was associated with 13% lower odds of frailty after adjusting for age, sex, and fasting time. The association weakened after adjusting for red blood cell volume, suggesting blood cell composition partly explains the link.

💡 Lower circulating NAD+ is associated with frailty, though causation remains unestablished.

🎖️ Top 10% journal 🔗 GeroScience Journal Article 🗓️ Sep 16

Implications

The week's papers converge on a single uncomfortable question: if senescence, NAD+ depletion, and failed cellular cleanup are driving aging across organs simultaneously, does treating any one pathway actually move the needle — or does meaningful intervention require hitting several at once?

Studies in this issue

Primary sources used for this newsletter.

A blood vessel cell pathway linked to blood vessel decline and overall aging
main storyScience advances2026-09-16PMID 42748238
Early signs of cell aging and treatment targets in a mouse model of ALS with TDP-43 mutation
key findingNeurobiology of disease2026-09-18PMID 42759848
A molecular pathway linking body signals to thinking problems in women during midlife
key findingNeuron2026-09-18PMID 42759510
Biological aging clocks differ by sex across organs and molecular data
key findingNature medicine2026-09-16PMID 42749890
Removing aging heart cells improves age-related heart changes in mice
key findingExperimental physiology2026-09-14PMID 42734482
GLP-1 receptor drugs, aging-related gene changes, and possible lifespan extension with medicine
key findingExperimental gerontology2026-09-14PMID 42735804
Blood levels of NAD+ linked to frailty in older adults living in the community
key findingGeroScience2026-09-16PMID 42744962