Fight Aging!

The more severe later stages of Alzheimer's disease are characterized by altered forms of tau protein aggregating inside neurons to cause dysfunction, inflammation, and cell death. Researchers here show that tau can spread between neurons via extracellular vesicles, and identify the protein arc as necessary to this process. Once a mechanism involved in the spread of pathological proteins is developed, it is potentially a target for future therapies that might slow the progression of disease.

Neurodegenerative diseases are characterized by protein aggregation in specific brain regions that spread across the brain as the disease progresses. A major histopathological hallmark of Alzheimer's disease (AD) and tauopathies, such as frontotemporal dementia (FTD) and chronic traumatic encephalopathy, is intracellular neurofibrillary tangles that consist of misfolded tau protein. During aging, tau becomes hyperphosphorylated, resulting in misfolding and a decreased affinity for microtubules. Tau pathology is transmitted cell to cell, and the spread and levels of pathological tau strongly correlate with the degree of cognitive decline in AD patients.

We find that the neuronal gene Arc is critical for the release of tau in neuronal extracellular vesicles (EVs) via a direct protein-protein interaction. Brain extracellular vesicles (EVs) purified from transgenic rTg4510 mutant tau mice (rTgWT) crossed with Arc knockout mice (rTgArc KO) contain less tau and reduced tau seeding potential. Both Arc and tau are co-packaged in mouse and human brain-derived EVs. Moreover, Arc levels in brain-derived EVs isolated from human Alzheimer's disease (AD) brains show a strong positive correlation with phosphorylated EV-tau levels. rTgArc KO mice have increased accumulation of intracellular tau and a modest increase in cell toxicity early in disease progression. Strikingly, intercellular tau transmission is almost absent in Arc KO mice. These results show that Arc is critical for the packaging of tau in EVs, which plays a significant role in intercellular tau transmission.

Link: https://doi.org/10.1016/j.cell.2026.06.008

The gut microbiome generates a vast range of metabolites, some beneficial or even necessary to health, and some actively harmful, provoking chronic inflammation or other dysfunction. With age the balance of microbial populations making up the gut microbiome changes for the worse. Researchers have observed declines in the generation of some beneficial metabolites and increases in the generation of some harmful metabolites. Among the harmful metabolites, the neurotoxic imidazole propionate has been shown to accelerate atherosclerosis, and evidence suggests a contribution to a range of other age-related conditions. Here, researchers report on evidence in mice and humans for imidazole propionate to accelerate the pace of neurodegeneration leading to Alzheimer's disease.

The gut microbiome modulates metabolic and neurovascular processes implicated in Alzheimer's disease and related dementias (ADRD), but the underlying mechanisms remain unclear. Here, we identify the bacterial metabolite imidazole propionate (ImP) as a modifier of ADRD pathology.

In a cohort of 1,196 cognitively unimpaired adults, higher plasma ImP levels were associated with lower preclinical cognitive scores and biomarkers of ADRD, both cross-sectionally and longitudinally. Fecal metagenomic analysis linked putative ImP producers to ADRD phenotypes. Genome-wide integrative analysis revealed a locus on chromosome 12 associated with both plasma ImP levels and AD risk in humans, supporting a host genetic contribution to ImP regulation and a causal role of this metabolite in AD.

In mice, chronic ImP administration exacerbated AD-like pathology. ImP impaired brain endothelial barrier and promoted tau hyperphosphorylation in primary neurons, an effect blocked by glycogen synthase kinase-3β inhibition. Together, this study links ImP to hallmarks of neurodegeneration and suggests that targeting ImP may represent a potential strategy to modify ADRD risk.

Link: https://doi.org/10.1038/s41467-026-74744-z

The retina is considered a part of the central nervous system. As is the case for the brain, a barrier of specialized cells surrounding the blood vessels supplying retinal tissue controls the passage of molecules between blood and tissues. This barrier becomes dysfunctional with age and age-related conditions, and leaks inappropriate molecules into retinal tissue to cause further damage and dysfunction. Again, this is very analogous to barrier dysfunction in the brain, and is thought to be a major contributing factor in age-related neurodegeneration and consequent degenerative conditions.

One of the approaches under development for the treatment of damaged retinal tissue, such as in the context of macular degeneration or diabetic retinopathy, is to produce new cells that can replace dead or dysfunctional cells, or otherwise help to improve function via a health profile of secretions. In today's open access paper, researchers report on generation of endothelial cells of the retinal barrier from induced pluripotent stem cells. When introduced into a damaged mouse retina, these cells help to repair tissue and restore a functional vasculature.

Derivation of functional retinal endothelial cells from human pluripotent stem cells for therapeutics and modelling

Retinal tissue has the highest energy and oxygen usage in the body due to the retina's intense and continuous neuronal activity. This demand leads to a crucial reliance on the inner blood-retina barrier (iBRB) to maintain ocular homeostasis. The iBRB is a specialized anatomical unit composing the vasculature located within the internal retinal layers of the central nervous system. Retinal endothelial cells (RECs) in the iBRB are continuous endothelial cells (ECs) that form tight junctions to regulate the diffusion of small molecules, such as ions and water, across their cell-cell interface.

Dysfunction and vascular leakage of the iBRB have been identified as a hallmark of numerous retinal microvascular diseases, including diabetic retinopathy (DR), the leading cause of blindness and a common pathology found in patients with diabetes mellitus. The breakdown of the iBRB occurs due to prolonged hyperglycaemia exposure, leading to increased permeability of the endothelial barrier and reduced oxygen delivery to the retina, causing ischaemia. As DR progresses, it can eventually lead to bleeding, retinal detachment and irreversible blindness.

In this study we harnessed Wnt-β-catenin signalling to derive RECs from human induced pluripotent stem cells (iRECs) that can generate a continuous endothelial barrier with a characteristic retinal phenotype and genotype as well as iBRB functionality. We established the therapeutic potential of the iRECs for the ischaemic eye using an oxygen-induced retinopathy (OIR) mouse model. When injected into oxygen-induced retinopathy mice, iRECs integrated into the host vascular network and revascularized the ischaemic eye, rescuing the tissue.

The growth in number of senescent cells with age is an important mechanism of degenerative aging. Many studies in mice have demonstrated rapid rejuvenation and reversal of many different aspects of aging and age-related conditions via selective destruction of senescent cells in aged tissues. Here, researchers review what is known of the way in which the age-related expansion of the senescent state in cell populations impedes stem cell function in older individuals. Stem cells support tissues by generating a supply of daughter somatic cells to replace losses, as well as via signaling that is important to regenerative capacity. As stem cell activity declines so too does tissue function and health.

Several cellular settings have been identified where senescence induction seems to exclude stem cell activity, thereby suggesting a functional competition between the two processes. One such example are mesenchymal stem cells (MSCs) used in therapy. Many of the potentially beneficial MSC properties are attributed to their ability to grow as high-density monolayers known as MSC sheets, which however can rapidly acquire senescence features under sustained high-density conditions. Another case of functional competition between senescence and stemness relates to bone marrow mesenchymal stem cells (BMSCs) which constitute a lifelong reservoir for somatic cell generation, and are shown to be significantly useful in bone regenerative medicine. It has, however, been observed that BMSC osteogenic differentiation is inhibited by senescence, thereby limiting the BMSC regenerative potential.

A considerable body of evidence where documented antagonism between senescence and stemness is pivotal for physiological homeostasis refers to muscle tissue. Muscle tissue regeneration relies heavily on satellite cells, a quiescent adult stem cell population whose regenerative capacity declines upon aging. Stellite cells from geriatric populations fail to retain their quiescent state under normal conditions, which extensively impacts their self-renewal and regenerative properties. Resting satellite cells in geriatric mice switch to a pre-senescence state thereby losing quiescence, a process driven by p16INK4A derepression. Thus maintenance of quiescence in adults, in fact, relies on repression of senescence.

Given that senescence is intrinsically characterized by proliferation arrest, while stemness refers to an inherent self-renewal capacity and production of differentiated progeny, the two cellular states are often perceived as mutually exclusive. Indeed, in this review we present an accumulation of evidence where the establishment of senescence may impose a barrier to stemness during natural processes such as aging, and upon reversing this functional competition (e.g. via genetic or pharmacological interventions) cell fate may change, as shown in multiple cell types and tissues such as MSCs, muscle satellite cells, dental pulp stem cells, or pancreatic β-cells.

Interestingly extensive functional synergy between the two states is widely observed in cancer, because the "dark side of senescence" may promote tumorigenic traits through senescent cell paracrine activity or even escape from the senescent state itself. Such activity was found to occur at least in B-cell lymphomas, liver, colon, and lung cancer.

Link: https://doi.org/10.18632/aging.206387

Accelerated aging conditions are not really accelerated aging conditions; each is a dysfunction in which one specific mechanism runs amok, generating damage and dysfunction that superficially resembles the damage and dysfunction of aging. Most of the known accelerated aging conditions are strongly connected to malfunctions in DNA repair, and dysfunction arises at least in part due to an accumulation of mutational damage in critical cell populations. Here, researchers describe an accelerated aging condition in which the underlying dysfunction is an increase in DNA methylation, distorting the epigenetic regulation of nuclear DNA structure and gene expression, again in ways that are superficially similar to the epigenetic changes of aging. Just as DNA repair disorders provide some insight into normal aging, with caveats, so too we might expect an epigenetic disorder to shed some light. The fine details still matter, however. Dysfunction is not equivalent to accelerated aging, even if it has the appearance of accelerated aging.

Declining tissue function and regenerative capacity underlie many chronic diseases. Experimentally establishing the mechanistic basis for such tissue aging presents substantial challenges, given decades-long timescales and multifactorial origins. Epigenetic alterations have been proposed to have a key etiological role, but whether they are correlative or causal remains a key unanswered question, as does their contribution to specific age-related pathologies.

Here we describe an epigenetically driven accelerated aging syndrome. We demonstrate that DNMT3A gain-of-function mutations in Heyn-Sproul-Jackson syndrome recapitulate age-related gains in DNA methylation (DNAme), cause multilineage stem cell dysfunction, and phenocopy aspects of aging in humans and mice. We also show that region-specific DNA hypermethylation at lineage-specific genes can explain reduced stem cell output and lineage skewing. Hence, starting from a Mendelian disorder, we implicate DNAme-mediated stem cell dysfunction in the etiology of medically important age-related hematological, bone and metabolic pathologies, which might be targetable by future therapies.

Link: https://doi.org/10.1038/s41588-026-02633-8

In recent years, researchers have noted that one variant of the BPIFB4 gene is associated with human longevity. This was discovered in the usual way, by noting that older populations tend to have a higher proportion of individuals carrying the variant than is the case for younger populations. In other words, individuals without the protective variant have an incrementally higher mortality rate. The longevity-associated variant of BPIFB4 appears to reduce cardiovascular dysfunction and mortality, and also reduces the chronic inflammatory signaling characteristic of aging. That slowed cardiovascular aging may or may not be entirely a consequence of the reduced inflammation; that remains to be determined.

Studies in mice have shown similar outcomes, and, interestingly, the BPIFB4 protein is robust enough to deliver orally and still produce benefits. Meanwhile, investigations of the underlying biochemistry of BPIFB4 and its role in the body continues, seeking a better understanding of how exactly it works.

Today's open access paper reports on new findings regarding the way in which BPIFB4 interacts with the immune system, which appears to be mediated via the activities of platelets. Platelets are cell fragments manufactured by megakaryocyte cells; they might be thought of as mini-cells that exhibit the surface features and some of the contents of their megakaryocyte progenitors. The primary purpose of platelets is to produce clotting when needed, but even when that is not happening, platelets are active participants in the complex dance of interactions between cells. Researchers suggest that effects hinge on the degree to which CD47 appears on platelet surface membranes, which offers a possible path to developing a drug to mimic BPIFB4 benefits.

The LAV-BPIFB4-Platelet-CD47 Axis: A Novel Mechanism Associated With Immune Resilience in Longevity

Long-living individuals (LLIs) possess remarkable genetic resilience, characterized by protective variants that confer immune robustness and resistance to age-related diseases. The longevity-associated variant of BPIFB4 (LAV-BPIFB4), enriched in centenarians, demonstrated pleiotropic benefits including reduced inflammation, cardiovascular protection, and immune system rejuvenation. However, the molecular mechanisms underlying these protective effects remain incompletely understood.

Here, we revealed that LAV-BPIFB4 fundamentally reshaped the immune features of platelets to establish enhanced immunomodulatory capacity through CD47 upregulation. Of note, centenarians displayed an elevated percentage of circulating CD47+ reticulated platelets (RPs), a condition mimicked by LAV-BPIFB4 carriers which exhibited significantly elevated CD47 levels both on RPs and mature platelets' surface. In agreement with an early acquirement of CD47 overexpression, MEG-01 megakaryoblastic cells overexpressing LAV-BPIFB4 produced CD47-high platelet-sized particles.

Functionally, platelets from LAV carriers suppressed monocyte activation and inflammatory cytokine production through CD47-dependent mechanisms, selectively reducing p38 MAPK activation while leaving NF-κB signaling largely unaffected in response to lipopolysaccharide. Recombinant LAV-BPIFB4 administration in vivo increased CD47 on murine platelets and reduced, ex vivo, LPS-induced monocyte activation, validating cross-species therapeutic potential. Critically, recombinant LAV-BPIFB4 protein phenocopies genetic effects, rapidly increasing CD47 expression on wild-type platelets through cytoskeleton-dependent trafficking mechanisms and conferring enhanced anti-inflammatory capacity. This might represent a translatable strategy to replicate some of the biological features associated with a longevity-associated variant beyond genetic carriers.

The nature of medical regulation makes it extremely expensive to develop a new drug, and considerably less expensive to find a new use for an existing approved drug. Thus repurposing drugs receives more attention than it perhaps should, and the typical outcome is a new marginal use rather than something impressive. This will happen for treatments for aging as well, no doubt. People will find that many existing approved drugs have some small effect on aging and life span in animal studies, and some of those will be marketed and used, and none of that will make any great difference to the world. What are the odds of discovering that an existing drug has an effect size similar to that of rapamycin? Which is to say ~20% life extension in mice and maybe a few years in humans, though that remains to be seen. That is an interesting question; it may be possible for effects on the order of a few additional years of life expectancy to hide in the existing human data because no-one looked that hard. Much more than that seems unlikely, though.

Despite the thousands of genes implicated in age-related phenotypes, effective interventions for aging remain elusive, due to the multifactorial nature of longevity and the interconnectedness of molecular components involved. Here we introduce a network medicine framework to map 2,358 longevity-associated genes onto the human interactome to identify drug-repurposing candidates capable of modulating specific hallmarks of aging. We find that genes associated with each hallmark form a connected subgraph, or hallmark module, allowing us to measure the network proximity of 6,442 compounds to each hallmark.

We then introduce a transcription-based metric, pAGE, which evaluates whether drug-induced expression shifts reinforce or counteract known age-related expression changes within each hallmark module. By integrating network proximity and pAGE, we identify drug-repurposing candidates targeting specific hallmarks and provide a falsifiable framework to leverage genomic discoveries for accelerating drug repurposing in longevity. Our findings are interpretable, revealing molecular mechanisms through which drugs modulate hallmarks.

Link: https://doi.org/10.1038/s43587-026-01161-8

Aging clocks cannot be trusted to produce useful data for any novel intervention in aging. They are produced via machine learning approaches applied to biological data from a large study population, and there is very little understanding of how underlying mechanisms of aging connect to the data used to build the clock. Thus effects on aging produced by way to change mitochondrial function or clear senescent cells may or may not be accurately reflected by any given clock - the only way to find out is to run a lengthy, expensive life span study, which defeats the point of having a quick and simple measure. The only practical way forward to make clocks more trustworthy in the near term, or at least to understand which clocks are most consistent, is to gather as much data as possible on their responses to interventions known to at least modestly impact aspects of aging, and that is exactly what is happening.

Aging-related chronic diseases are driven by multiple mechanisms, motivating efforts to develop feasible interventions that can attenuate biological aging. DNA methylation-based epigenetic clocks, particularly measures of the pace of aging such as DunedinPACE, are sensitive to relatively short-term changes in aging processes. However, evidence from randomized controlled trials remains limited. We conducted a randomized controlled trial to test a 12-week multimodal lifestyle intervention comprising exercise and dietary guidance involving daily consumption of yogurt containing Bifidobacterium longum BB536 on DNA methylation-based aging measures in overweight men aged ≥50 years.

The intervention group exhibited a significant deceleration in DunedinPACE, corresponding to an estimated 2.2% slower pace of aging, whereas no meaningful change was observed in the control group. Exploratory analyses further identified a significant reduction in DNAmCystatinC, a renal-related GrimAge surrogate marker, while no clock within the biological age remained significant after false discovery rate correction. These findings suggest that a feasible, multimodal lifestyle intervention-including exercise and dietary guidance with daily consumption of yogurt containing Bifidobacterium longum BB536-may be associated with short-term changes in selected DNA methylation-based aging measures. Larger and longer-term studies are warranted to confirm the durability and clinical relevance.

Link: https://doi.org/10.18632/aging.206386

Ethicists seem a little stuck on the idea that treatments to slow and potentially reverse aspects of aging are only available to the wealthy, or will only be available to the wealthy. Today's open access complaint about making the world a better place at least manages to also touch on what I think is the more pertinent issue, which is knowledge. One can't try interventions that seem plausibly likely to produce benefits in the matter of degenerative aging without knowing that the option is there. One can't make an assessment of the odds of benefit versus harm without knowing a fair amount about biology, mechanisms of action, and the state of the field. One can't accumulate that knowledge without understanding which of the many sources of information are lying through their teeth in order to make money. One can't substitute wealth for knowledge and pay middlemen to point in the right direction without knowing which of those middlemen are corrupt and selling a bill of goods. It's a knowledge problem all the way down.

The most plausible, well-studied initial approaches to treat aging are also readily available at generic drug prices. Rapamycin. Senolytic compounds like the dasatinib and quercetin combination. Or they are free if we're also counting exercise and calorie restriction. The next step up, exosome therapies and stem cell therapies, can be obtained for a few thousand dollars per treatment given a lot of legwork and cost comparison on the part of the patient. The futuristic approaches like partial epigenetic reprogramming? At some point there will be versions that cost little. Just wait.

I suspect that ethicists and journalists and others who like to grind axes on the activities of the wealthy are deceiving themselves. They look at a few exceptional and vocal wealthy people who are spending a great deal on personal health as a hobby and see that as broader reality, rather than a tiny minority engaged in doing unusual things with their time and funding. The reality is that most wealthy people do little that is out of the ordinary when it comes to their health, and have little to no knowledge regarding potential advances in the treatment of aging. Meanwhile, a relatively small number of interested non-wealthy people quietly put in the time to learn the bounds of the possible and undertake self-experiments by trying rapamyin or senolytics, or saving up for exosome treatments. The mainstream pays very little attention to that contingent, and perhaps justifiably so - as for the vocal wealthy self-experimenters, they are a tiny minority of the population.

Meanwhile, most people have no idea. Medicine and biology are not in their wheelhouse, why would they have any idea as to what is in process and speculative and potentially useful? The knowledge problem is the hard problem here, not the finance. Given something that may be useful, and costs little, how does one cut through the background noise of nonsense and self-interest to produce and present clinical proof and induce widespread use? It is a collective action puzzle, and our species does not have a good track record when it comes to solving those.

The Ethics of Extending Life: Longevity Medicine and Health Inequity

In one survey, nearly 80% of 1000 US respondents said they'd like to live to be 120 years old, but only if they remained mentally and physically healthy. Without that hypothetical guarantee, far fewer people wished to live such a long life. We not only want to live longer, we want to live longer and better. From stem cell therapy to biomarker tracking, from genomics to AI algorithms that support early disease detection, medicine has entered a new era in which some view aging as a condition that can be managed and mitigated, provided the right tools are used.

Due to limited accessibility and high costs, those in economically and socially privileged positions have been the first to benefit from these advancements. As life-lengthening medical interventions continue to develop, health span extension may become stratified along socioeconomic lines, concentrating its benefits among the already privileged. Without intentional policy and ethical frameworks, these innovations may deepen population health inequities.

There is another, more subtle accessibility challenge facing longevity medicine: "Even if you made every longevity medicine intervention free, you still need to interpret all that information." That requires the consumer to possess a high degree of health literacy, which is typically higher in well-educated, high-income individuals. "Wealthy patients walking into longevity clinics aren't just buying the intervention, they're buying someone to do that cognitive work and navigation for them, to be the quarterback of their health, or the CEO of their health, which is a service that's almost completely absent from primary care for most other people." Without someone to provide context and guidance, the large amount of data that longevity medicine testing reveals may simply be disregarded, or worse, widen disparities.

Longevity medicine offers fantastic potential for increasing health span - a hope that many of us dream of - but the future of longevity medicine will be defined by not just how long we can live, but by who gets the opportunity to do so.

Pulmonary fibrosis is an age-related condition. Good evidence connects it to the burden of senescent cells in the aging lung, but its causes are otherwise relatively poorly understood. Therapeutic options remain poor, and the prognosis for patients is quite ugly. Fibrosis is nanoscale scarring, an inappropriate buildup of excess extracellular matrix that is disruptive to tissue function. Researchers here explore a loss of the capacity of fibroblast cells to degrade extracellular matrix structures in aged tissue, and identify a regulatory gene that can be overexpressed to produce a greater defense against fibrosis in aged mice.

Idiopathic pulmonary fibrosis (IPF) is a progressive and often fatal interstitial lung disease whose incidence and severity increase markedly with age, indicating that aging is a primary risk factor for IPF. A study in murine models demonstrated that while bleomycin-induced pulmonary fibrosis (PF) can resolve spontaneously in young mice, this reparative capacity is significantly impaired in older animals, potentially causing persistent fibrosis.

A key mechanism underlying extracellular matrix (ECM) degradation involves the phagocytosis of collagen fibrils by fibroblasts and macrophages and their subsequent lysosomal degradation. Aging has been shown to impair the capacity of lung fibroblasts to degrade collagen independently of matrix metalloproteinase activity. Therefore, we hypothesized that an age-associated decline in collagen phagocytosis by fibroblasts is linked to lysosomal dysfunction. However, the upstream regulators governing this process remain poorly defined.

In vivo, aged mice showed impaired fibrosis resolution and reduced lung fPRDM16 levels. Fibroblasts from aged mice exhibited reduced collagen I phagocytosis, elevated lysosomal pH, and increased mitochondrial reactive oxygen species (mitoROS). Enhancing lysosomal function with rapamycin or scavenging mitoROS with mitoquinone restored phagocytosis. fPRDM16 expression was downregulated with age and upon transforming growth factor-β (TGF-β) stimulation. Its overexpression rescued phagocytic defects, improved lysosomal acidification, and reduced mitoROS, thereby disrupting a pathogenic mitochondria-lysosome feedback loop.

We conclude that fPRDM16 downregulation in aging impairs fibroblast-mediated collagen clearance via a mitochondria-lysosome dysfunction loop. Targeting fPRDM16 may represent a novel therapeutic strategy to promote fibrosis resolution.

Link: https://doi.org/10.1016/j.cmp.2026.02.002

If used sensibly, models of aging can offer some insight into the bounds of the possible with regard to which classes of biological mechanism are more or less important in determining pace of aging, onset of disease, and life span. Researchers here use a specific type of model, the saturating removal model of damage accumulation, and tinker with the parameters to see which of the processes represented by those parameters best predict the observed range of life spans across species. Perhaps the most interesting outcome is that mice and humans end up in different broad buckets in terms of categorizing how mechanisms of aging interact; this is far from the only study to suggest that this is the case.

The saturating removal (SR) model was defined and calibrated based on longitudinal damage measurements in mice (senescent cells) and Escherichia coli (membrane damage). The model is based on the simplifying hypothesis that the damage that causes aging can be summarized by a scalar x and that life cannot persist above a certain level of x. The biochemical nature of x can be different in each species. The SR model describes the dynamics of damage by a stochastic differential equation that includes production, removal, and noise. Production rises linearly with age, whereas removal saturates at high damage. Death occurs when damage exceeds a threshold. The SR model explains many quantitative patterns of aging including Gompertz and Weibull hazard curves, distributions of human frailty index, disease incidence curves, and heritability of lifespan.

Different species age in similar ways but their lifespans differ by orders of magnitude. It is not clear how these similarities and differences arise from the accumulation of damage that underlies aging. Does long lifespan arise from reduced damage production, increased removal, or enhanced robustness to damage? Here we apply the saturating removal model and fit it to survival data from well-studied species. Several parameters have near-universal values including ratios of removal rate, noise amplitude, and death threshold. The model parameter that best predicts lifespan is the damage production rate, which spans seven orders of magnitude.

We identify two distinct aging regimes: ballistic aging where damage production outpaces removal, characterizing yeast, nematodes, flies, and mice, and quasi-steady-state aging, where damage tracks a moving set point of balanced production and removal, characterizing humans, dogs, guinea pigs, and cats. These results provide a mechanistic model-based basis of comparative aging that awaits experimental validation.

Link: https://doi.org/10.1038/s43587-026-01138-7

Intermittent mild hypoxia has been shown to slow aging and improve health in animal studies, and is used in medicine in some contexts. It is a form of stress and encourages a hormetic response from cells that on balance improves health. Long term hypoxia or severe hypoxia tips over into outright harm, overwhelming any beneficial mechanisms that attempt to compensate. Human data suggests that high altitude living, at the point where mild hypoxia is induced by the lower oxygen content of the air, results in accelerated aging. For example, researchers have shown that these populations exhibit accelerated immune aging. These populations are not yet large enough or well studied enough to go much beyond this sort of investigation of a few aspects of their physiology. Epidemiology for more solid evidence of accelerated aging is lacking, for example, and much of the existing data on mortality and age-related disease could be explained by comparative poverty rather than any sort of comprehensive acceleration of aging.

Recall that epigenetic age is usually assessed from a blood sample, and the only cells in a blood sample with nuclei and nuclear DNA are immune cells. Thus epigenetic age assays are really a measure of immune aging rather than systemic aging. To the degree that those two correlate, this is fine. But they are not the same thing, and the immune system is subject to pressures and mechanisms not relevant to other cell types in other tissues. Thus epigenetic age in those other cell types and tissues is more interesting in a research context.

Today's open access paper provides more evidence for intermittent hypoxia to accelerate epigenetic age, though the question remains as to whether aging is a good description for is actually occurring inside cells, meaning a shift in nuclear DNA structure in response to low oxygen levels. In mice, the researchers looked at a few different tissues, and found that epigenetic age acceleration only occurred in old mice, and went away when hypoxia treatment was halted. The researchers also note human data from the AltitudeOmics study, which involved blood samples rather than tissue samples, and so measured immune aging rather than tissue aging.

Intermittent hypoxia induces reversible epigenetic age acceleration in old mice

Epigenetic mechanisms are considered adaptive regulators of gene expression, yet mechanisms driving aging-associated DNA methylation remain unclear. Prior work hinted that epigenetic aging might reflect a response to oxygen availability, with age-differential methylation in immune cells enriched near binding sites for hypoxia-responsive factors ARNT and REST. To test this hypothesis, we exposed adult (11 months) and old (23 months) mice to 1 month of intermittent hypoxia (IH) followed by normoxic recovery.

IH induced epigenetic age acceleration in lungs, spleen, and heart in old mice only. This acceleration reversed upon return to normoxia. Reversible shifts were enriched at bivalent domains and PRC2 targets, indicating oxygen-sensitive chromatin remodeling.

Human translational validation from the AltitudeOmics project in which 19 young adults underwent baseline testing near sea level then again after rapid ascent to 5260m confirmed rapid, conserved epigenetic aging. Our findings establish oxygen availability as a primary, conserved modulator of epigenetic aging across tissues and species, showing that oxygen fluctuations are a potent, reversible driver of epigenetic aging.

Sadly, we live in an age in which the media likes to generate conflict, and in which the role of personal responsibility in most aspects of life (and certainly in the matter of medicine) is denigrated. It is a culture that rejects risks, costs, and benefits that cannot be quantified easily, and demands a centralized, legalistic approach as to who is and is not permitted to take those risks. On the other side of the fence, those taking the risk of trying new therapies that are not fully understood are in all too many cases doing it without sufficient forethought and planning. Too many people take wishful thinking and popularist rhetoric as fact. They don't want to understand the details, and look for quick, certain answers where quick, certain answers doesn't exist. This is not a great environment in which to try to promote a responsible attitude to medical self-experimentation and risk, such that self-experimentation is encouraged as a way to make progress towards a better world in which people are healthier than would otherwise be the case. But what is the alternative? Age to death on the normal schedule and not rock the boat? Sometimes the boat needs to be rocked.

Bryan Johnson often tinkers with his daily regimen of drugs, peptides in the form of both supplements and injections and other medical interventions in pursuit of a longer life. He's part of a growing crowd of tech entrepreneurs who are seeking extra years by hacking their own bodies - and sharing their exploits widely through social media and other channels. Wealthy longevity evangelists are often seen as translators of early-stage science to the public, who turn preliminary or anecdotal findings into so-called stacks that combine supplements, other compounds, protocols and therapies, long before FDA approval.

But there is a danger to this growing phenomenon: researchers who study ageing and longevity warn that these biohacks have not been clinically tested, meaning that it's unclear whether they work or might harm people. There is no medical intervention that is proven to extend human life by targeting ageing itself, says Andrew Steele: "There probably are things on our radars that might work, but nothing has ever been tried in humans." Nir Barzilai is torn about the impacts that the biohackers have. Take Johnson's tinkering with various supplements and drugs, which is usually based on some kind of evidence: "If you're asking, 'Is he taking something that doesn't make sense?' I would say, no, these things are based on biology but not on clinical evidence."

Neither Steele nor Barzilai are cynics. Both say that some of the protocols being tested and touted by Silicon Valley elites could have a meaningful impact on lifespan and healthspan - the time during which people are not affected by chronic disease and disabilities related to ageing. But the evidence isn't there yet. Matt Kaeberlein calls it "a signal-to-noise problem". In the limited available data about these interventions, he says, "there's signal there, but there's a whole lot of noise". That makes it hard for the public to separate the two.

Link: https://www.scientificamerican.com/article/silicon-valleys-longevity-biohackers-are-engaged-in-a-dangerous-experiment/

Hematopoietic cell populations reside in the bone marrow. A tree of ever more specialized progenitor cell populations descends from the root hematopoietic stem cell population, responsible for ultimately producing red blood cells and white blood cells. Hematopoietic stem cell populations are known to become damaged and dysfunction with age, and this is one of the contributions to immune system dysfunction in later life. It also produces effects such as platelets that are more prone to causing inappropriate clotting and thrombosis. Here, researchers provide evidence to suggest that the intermediate hematopoietic progenitor cell populations are much less impacted by aging than is the case for hematopoietic stem cells, and might be buffering the loss of stem cell function to allow for maintained hematopoietic function. It is a little early to understand what this might mean for approaches to therapy, and what the implications are for the importance of hematopoietic stem cell function in aging. It is certainly interesting, however.

Aging of the hematopoietic system has profound consequences for organismal health and longevity, attributed to the well-characterized functional aging of hematopoietic stem cells (HSCs). Here, we tested whether progenitor cells may demonstrate age resistance to enable hematopoietic homeostasis throughout life despite the functional decline of upstream HSCs. Strikingly, our results revealed unwavering reconstitution capacity by young and old progenitors, demonstrating that intermediate progenitors are functionally unaffected by aging and placing Flk2+ multipotent progenitors (MPPFs) as a potential source of age resilience.

This unique finding was emphasized by unchanged transcriptomic, proliferation, and mitochondrial capacity of young and old MPPFs, revealing remarkable similarities upon aging. Considering that HSCs functionally decline with age, yet intermediate progenitors remain unperturbed and "age resilient", we posit that MPPFs may play an essential role in protecting downstream progenitors from inheriting age-related properties from HSCs. We propose three potential mechanisms for how MPPFs maintain hematopoietic integrity and homeostasis with age.

Link: https://doi.org/10.1016/j.stemcr.2026.102965

Genes produce proteins at a pace determined by epigenetic control over nuclear DNA structure. That epigenetic control changes with age for reasons that are incompletely understood. A promising possibility is that repeated activation of DNA repair processes depletes specific factors needed for maintenance of DNA structure, but that needs further confirmation. The pace of protein production changes in a characteristic way with age for countless different proteins. Of that large number, some are known to cause harm, and are associated with aspects of degenerative aging. These are potential targets for gene therapies; I listed a large number of them some years ago, and that set has only grown since then.

Gene therapy technology has existed for decades, but is not yet very broadly used. A narrow subset of such therapies are becoming increasingly used in the medical tourism industry as potential treatments for aging. Why aren't we swimming in dozens of commercially available gene therapy implementations to dial up expression of gene X or dial down expression of gene Y to improve late life health? The short answer is that gene therapy has a delivery problem. It is somewhere between very hard and impossible to deliver gene therapies safely and effectively to most tissues in the body, given the tools presently available. The therapeutic applications being explored most aggressively these days largely fall into a small set of categories, where local delivery of a relatively small amount of a well-explored gene therapy vector (such as plasmids or AAV) does the job. For example, to turn a small number of fat cells into factories to produce a beneficial signaling protein that will circulate throughout the body - such as klotho, follistatin, and so forth. Or where a delivery mode can hit desired tissues with high specificity, such as intranasal delivery of AAV to reach parts of the brain.

Gene therapies that can reliably and selectively produce expression in a small inner organ require direct injection, which developers largely reject as an option outside the context of severe disease. Intravenous injection of gene therapy vectors that produce sufficient expression in a target inner organ without overloading the liver or bearing an unacceptably high risk of an immune reaction is an unsolved problem for near all target organs. Further, systemic injection of high dose gene therapy vectors has caused deaths in recent years, and is thus not in favor for anything but the most severe disease conditions. Being able to change gene expression in cells throughout the body with a single intravenous treatment (again without overloading the liver or provoking the immune system) also remains a pipe dream; while a few programs offer hope for progress on this front, no established gene therapy vectors are capable of doing this.

Partial epigenetic reprogramming is thought to offer the potential to bypass targeting of individual genes by rejuvenating the control over DNA structure and gene expression. But this approach still suffers from all of the delivery issues of gene therapy, alongside the likely need for different dosage and duration in different tissues. At the end of the day, yes, the technological capability exists to change the behavior of aging cells for the better. It is trivial to do so in a cell in a dish. The delivery challenges are what prevents the research and development communities from bringing this capability into patients in the near term. For now the field is focused on only a few genes, approaches, and tissues that are a good fit for the limited delivery capabilities that exist.

Gene therapy for aging and longevity

Over 2000 genes have been linked to increased longevity in a variety of models, but the translation of these findings into clinical applications remains challenging. Gene therapy is a potential strategy for extending healthspan by targeting genes associated with longevity or age-related diseases. This approach involves transferring genetic material directly into target tissue using viral or nonviral vectors, thereby enabling the augmentation, suppression, or precise editing of genes. This review examines multiple gene therapy strategies and their respective technical challenges, with a particular focus on identifying the most promising genetic targets for future interventions.

Many different gene delivery vectors have been engineered in recent decades. They can broadly be divided into physical, chemical, and virus-based methods. All gene delivery vehicles must overcome the same set of issues: efficient delivery to target locations, evasion of host immune responses, sufficient packaging size, controlled expression levels, reversibility and stability, redosability, and cost-effectiveness. In other words, each vector represents a multidimensional optimization problem in which certain existing properties determine whether a vector is more suitable for some applications over others. In the context of longevity therapies, additional requirements include a broad distribution profile, very-long-acting and stable expression, and high safety standards, as such interventions must remain effective over extended periods and are also intended for use in individuals without overt disease.

The main obstacle longevity gene therapies need to overcome is the ability to deliver the genes of interest to many or all tissues in the body. Most of the genes known to extend longevity are expressed intracellularly and across numerous tissues in the body. In this review, we identified multiple gene candidates from animal and human studies as potential targets for longevity gene therapies. Based on its advantages in gene delivery, AAV-mediated gene therapy is currently the most suitable platform for longevity gene therapy, but technical challenges remain, such as whole-body delivery and biomechanical limitations.

To accelerate the longevity gene therapy field, several key technical advancements are desirable. These include new AAV serotypes or vehicles for broader delivery across the body; better systems for controlled expression in individual organs, compact, reversible, or controllable expression systems; improved immunosuppressors to prevent anti-vector or anti-transgene immunity; compact molecular tools for safe and controlled integration; and new (possibly automated) production and quality control pipelines to reduce manufacturing costs.