The researchers began with a dose-response experiment in wild-type nematodes continuously exposed to 100, 200 or 250 nanomolar LSD from young adulthood. Each concentration was associated with longer survival than the vehicle control, with reported lifespan increases of 12.4%, 13.2% and 17.6%, respectively. The researchers selected 250 nanomolar for most subsequent experiments. Survival was analyzed with Kaplan–Meier curves and log-rank tests, with repeated independent experiments and at least approximately 120 to 180 animals per condition in the principal assays. The percentages describe survival in this laboratory model; they are not estimates of a human effect or clinical benefit.

Because longer survival does not necessarily mean that age-related deterioration has slowed, the team also measured lipofuscin, a fluorescent pigment that accumulates when cellular components are incompletely degraded. At day 10, treated animals had lipofuscin levels close to controls, but by day 15 the treated group showed a marked reduction. Fluorescence in the LSD group was 49.8% of the corresponding control value, with a reported p<0.0001. The observation is consistent with the authors’ interpretation that LSD delayed at least one age-associated accumulation in worms, although the study did not evaluate a complete set of healthspan measures or test whether the response would occur in mammals.

Genetic experiments indicated that serotonin-receptor pathways were associated with the different survival responses. LSD failed to extend lifespan in animals lacking the serotonin GPCRs SER-1 or SER-5. In contrast, it shortened lifespan in ser-4 mutants by 7.7% and in ser-7 mutants by 3.3%. These outcomes show that disruption of individual receptors can abolish or reverse the measured benefit. In tph-1 animals, which lack tryptophan hydroxylase and are therefore deficient in serotonin synthesis, LSD still extended lifespan by 9.3%, although the effect was smaller than in wild type. Thus, endogenous serotonin production was not strictly required in the tested animals, while the integrity of multiple serotonin receptors influenced the response.

Several traits measured in LSD-treated worms resembled phenotypes associated with caloric restriction. Treated animals laid fewer eggs during the reproductive period, were shorter than controls on both day 1 and day 10, and showed delayed vulval development. At the end of the L4 larval stage, 31.7% of treated animals had fully developed vulvas, compared with 68.3% of controls. The developmental result is consistent with altered timing of growth, and the body-size and reproductive changes overlap with features reported for caloric restriction in C. elegans. However, the experiments did not demonstrate that LSD directly reduced TORC1 activity or that TORC1 was the mediator of the lifespan effect.

Nutritional context was decisive. In the eat-2 mutant strain, a genetic model of dietary restriction used in C. elegans, LSD produced no difference in survival compared with controls. When the researchers reduced bacterial food availability by diluting the standard bacterial suspension tenfold, LSD not only failed to extend lifespan relative to the restricted control group but shortened it by 9.2%. The lifespan benefit was therefore absent in both tested forms of dietary restriction, and became detrimental under the diluted-food condition. These findings show that the response observed in well-fed wild-type animals cannot be generalized to all nutritional or genetic contexts.

The results also did not appear to arise from a simple reduction in feeding. Pharyngeal pumping was not reduced on day 1; by day 5, treated worms pumped more frequently than controls, reaching 209.2 contractions per minute compared with 159.4 in the untreated group. Direct food-consumption assays, which quantified bacterial biomass remaining on plates, found no significant difference between treated and control groups on day 1 or day 5. The authors interpret the higher day-5 pumping rate as compatible with preservation of feeding capacity during aging rather than reduced appetite, because the treated value remained close to the day-1 level measured in control animals. The assays support that interpretation under the conditions tested but do not exclude changes in feeding behavior at other times.

Molecular and metabolic readouts changed over time rather than remaining fixed. PHA-4::GFP fluorescence, a reporter for a transcription factor downstream of TOR signaling, was elevated on day 1, reduced on day 5 and similar to control by day 10. Lipid staining followed a comparable trajectory: total lipid content increased to 125.7% of the day-1 control value, fell to 70.2% of the corresponding control on day 5 and was near baseline on day 10. Nuclear localization of HLH-30, a transcription factor associated with reduced TOR activity, increased from 21% in controls to 53% in treated animals on day 10. In raga-1 mutants, which lack a Rag GTPase needed for TORC1 activation, LSD shortened lifespan by 11.6% instead of extending it. Together, these observations are consistent with time-dependent remodeling involving nutrient-sensing processes, but they do not resolve the precise molecular mechanism.

Continuous exposure was not required for the measured survival benefit. Researchers treated young adults with 250 nanomolar LSD for 24, 48, 72, 96 or 120 hours and then removed the compound for the remainder of their lives. Every exposure interval was associated with a benefit, with reported lifespan increases ranging from 5.6% to 12.1%. The finding indicates that exposure during early adulthood was sufficient to produce a lasting survival effect in this model. The authors also noted that direct clearance controls would be needed to exclude residual exposure, and that the benefit was detectable across multiple portions of the survival curve rather than being restricted to late survival alone.

Several limitations constrain what can be concluded. Most longevity assays used 5-fluorouracil to prevent eggs from hatching and reduce the influence of progeny on lifespan measurements. Although it was applied identically to treated and control groups, pharmacological suppression of reproduction can introduce confounding effects, including possible interactions with LSD treatment or the reduced-food condition. The authors said confirming the findings without 5-fluorouracil, with progeny controlled manually, would be an important next step. The experiments also involved one species, laboratory growth conditions and outcomes that depended on genotype and food availability. Within those limits, the study identifies LSD as a useful experimental probe for examining how serotonin-receptor signaling and nutrient-sensing readouts may relate to lifespan and age-associated traits in C. elegans, not as evidence of a human anti-aging treatment or a reason for self-experimentation.

Subject of Research: Experimental effects of LSD on lifespan and age-associated traits in Caenorhabditis elegans.

Article Title: Lysergic acid diethylamide extends lifespan in Caenorhabditis elegans

Article References: S. Carrilho, B., Teixeira Duarte Silva, A., Martins, I., Moura, A., Vilas, M., C. Ventura, M. A. V., Moll, F., Aguilaniu, H., Domith, I., & Rehen, S. (2026). Lysergic acid diethylamide extends lifespan in Caenorhabditis elegans. Biogerontology, 27(6), Article 184. https://doi.org/10.1007/s10522-026-10521-1

Image Credits: AI Generated

DOI: 10.1007/s10522-026-10521-1

Keywords: LSD, Caenorhabditis elegans, longevity, serotonin receptors, lipofuscin, caloric restriction, nutrient sensing, metabolic remodeling, TOR signaling, Lysergic, acid, diethylamide

The research, published in Frontiers in Aging, analyzed autophagy flux in primary skin fibroblasts from apparently healthy male donors aged 20, 38, 74, and 96 years. Fibroblasts are a widely adopted aging cell system because they retain the cellular and molecular signatures of their donors: the skin is directly exposed to ultraviolet radiation, pollutants, and genotoxic agents over a lifetime, so fibroblasts from older individuals carry the in vivo wear of their chronological age into a controlled culture dish. By comparing cells across this age range, the team could trace how each phase of autophagy changes as human cells grow old.

Autophagy is a multi-step assembly line. Under starvation signaling, inhibition of mTOR activates the ULK1/2 kinase complex, which nucleates a phagophore. Two ubiquitin-like conjugation systems, ATG12/ATG5/ATG16L and LC3, elongate and seal the membrane into an autophagosome. The SNARE protein syntaxin 17 is then recruited to mature autophagosomes, licensing their fusion with lysosomes to form autolysosomes, where hydrolases degrade the luminal content. Because each step can fail independently, measuring flux across the whole pathway is essential for designing therapies that reactivate the specific phase that is actually broken.

The master switch of this pathway is transcription factor EB, or TFEB, which controls the expression of autophagy and lysosomal genes. Under nutrient-rich conditions, phosphorylated TFEB sits inert in the cytoplasm; during stress, calcineurin-mediated dephosphorylation drives it into the nucleus. When the researchers examined fibroblasts by confocal microscopy, TFEB activation looked surprisingly intact, even enhanced, in aging. Starvation pushed TFEB into the nuclei of cells from all donors, and the 96-year-old fibroblasts showed the strongest nuclear signal, even accumulating TFEB in the nucleus under normal, non-starved conditions.

That nuclear buildup translated into transcription. Quantitative RT-PCR showed that the TFEB target genes LAMP1, SQSTM1, and MAP1LC3B responded to starvation in cells from all ages, with SQSTM1 and MAP1LC3B transcripts rising markedly higher in the 96-year-old fibroblasts than in the 20-year-old controls. The authors interpret this premature nuclear accumulation of TFEB in old cells as a compensatory alarm: a signaling mechanism mobilized to counteract the impaired flux and lysosomal dysfunction discovered downstream. Alternative explanations, such as altered mTORC1- or ERK-mediated phosphorylation trapping TFEB in the nucleus, or an age-dependent decline in CRM1-mediated nuclear export, remain to be tested.

Autophagosome formation also held up. Treating cells with chloroquine, which blocks autophagosome-lysosome fusion, revealed LC3-positive puncta in fibroblasts from all donors, and Western blotting of the LC3-I to LC3-II conversion showed that autophagosomes formed with similar efficiency across the age spectrum. Flow cytometry with Cyto-ID dye even found a greater accumulation of autophagic vacuoles in the older cultures, implying that the early machinery operates at least as vigorously in old cells, likely as an active coping mechanism against age-related cellular stress.

The picture changed when the team probed the end of the line. The selective autophagy receptor p62, which is itself degraded in autolysosomes, normally accumulates when flux is blocked. Yet when fibroblasts were starved and treated with the lysosomal inhibitors E64D and pepstatin A, young and middle-aged cells accumulated LC3-II and p62 robustly, while cells from the 74- and 96-year-old donors showed no significant accumulation at all. The lysosome-dependent turnover of the canonical autophagy markers had decayed with age, a result the authors confirmed with bafilomycin A1, an inhibitor of the V-ATPase pump that arrests autophagosome-lysosome fusion.

Confocal colocalization assays pinpointed where the assembly line jams. In young fibroblasts, starvation significantly increased the overlap between LC3 and syntaxin 17, indicating enhanced autophagosome maturation, with Pearson correlation coefficients rising from 0.35 to 0.63. In old fibroblasts, starvation produced no such increase, with coefficients of 0.42 versus 0.39. Similarly, the colocalization of LC3 with the lysosomal membrane protein LAMP1, an indicator of autophagosome-lysosome fusion, rose sharply in young cells under starvation but only marginally in aged cells. The final two steps of autophagy, maturation and fusion, had quietly failed.

The culprit appears to be the lysosome itself. LysoBrite staining revealed that fibroblasts from the oldest donor carried a significantly increased abundance of lysosomes, and starvation enlarged lysosomes in all cultures, with the most expanded organelles in the 74- and 96-year-old cells. These enlarged lysosomes were unresponsive to autophagy induction: the 96-year-old fibroblasts showed the greatest basal lysosomal activity but failed to activate it further under starvation, unlike cells from younger donors. Consistent with overloaded, dysfunctional organelles, lipofuscin, the non-degradable autofluorescent pigment formed by incomplete lysosomal digestion, accumulated heavily in the oldest fibroblasts, and starvation could clear it in young cells but not in old ones.

The findings carry a clear therapeutic message. Rather than simply switching autophagy on, interventions in aging may need to target the final steps of the pathway: TFEB activators to stimulate lysosomal biogenesis through the CLEAR gene network, mTOR inhibitors such as rapamycin to restore flux, and lysosomal acidification enhancers, from small molecules to acidic nanoparticles, to boost enzymatic activity. The authors acknowledge that a single donor per age group limits generalizability, and future studies with additional donors will be needed to confirm whether late-stage autophagy impairment is a universal hallmark of fibroblast aging. But the core conclusion stands: in old human cells, the recycling plant’s opening hours are fine; it is the crusher at the end of the line that has broken down.

Subject of Research: Impaired autophagy flux and lysosome dysfunction in aged human fibroblasts

Article Title: Impaired autophagy and lysosome function in human fibroblast aging

Article References: Unzueta-Mendoza, J. J., García-Aguirre, I., Königsberg, M., Arrieta-Cruz, I., Lizcano-Meneses, S., Magaña, J. J., Alarcón-Aguilar, A., & Cisneros, B. (2026). Impaired autophagy and lysosome function in human fibroblast aging. Frontiers in Aging, 7, Article 1971981. https://doi.org/10.3389/fragi.2026.1971981

Image Credits: AI Generated

DOI: 10.3389/fragi.2026.1971981

Keywords: autophagy, lysosomes, TFEB, fibroblast aging, lipofuscin, autophagosome-lysosome fusion, LC3, p62, cellular recycling, aging biology, Impaired, lysosome

The experiment was carefully constructed to separate two questions that are often tangled together: does too much food harm the ovary, or does the wrong kind of food? Three-month-old C57BL/6 mice, the laboratory equivalent of young adulthood, were divided into four groups of twelve. One group received a standard control diet. A second received a low-calorie version of a Western diet, engineered to carry the same saturated fats, refined sugars, and high-glycemic carbohydrates as a typical Western diet but at a lower energy density. A third ate a full Western diet, and a fourth a conventional high-fat diet. All animals ate freely for seventeen weeks, roughly the span from three to seven months of age, while researchers tracked body mass, food intake, metabolic health, reproductive cycling, and ovarian architecture.

The metabolic results followed a predictable gradient. Mice on the full Western diet and the high-fat diet gained progressively more weight than controls, with significant divergence appearing by week three in the high-fat group and week seven in the Western diet group. Intra-abdominal fat mass rose sharply in both groups, and total caloric intake was higher than in the control and low-calorie Western diet groups. Insulin and glucose tolerance tests told a consistent story: high-fat diet mice showed the blunted glucose clearance and reduced insulin responsiveness, with Western diet animals falling in between. Liver histology revealed mild steatotic changes, and serum cholesterol climbed in both high-calorie groups. Yet the most striking metabolic surprise came from the low-calorie Western diet mice, who ate no more calories than controls but still developed elevated fasting glucose, higher liver weights, and worse histological liver scores.

That surprise became central when the researchers turned to the ovary. Using Picrosirius Red staining to visualize collagen, they found that mice on the Western and high-fat diets had significantly increased collagen deposition in the ovarian stroma compared with controls. The low-calorie Western diet group landed squarely in between, statistically indistinguishable from both the controls and the high-calorie groups. Because these animals consumed no more energy than the control mice, the result implies that dietary composition, the saturated fats, refined sugars, and high-glycemic carbohydrates themselves, can drive fibrotic remodeling of the ovary even without caloric excess. The authors caution that this intermediate finding needs confirmation with larger cohorts, but its implications are difficult to ignore.

Why does stromal collagen matter? The ovarian stroma is not passive packing material. It houses the blood vessels, immune cells, and signaling networks that nourish follicles and mediate the constant crosstalk between oocytes, granulosa cells, and the vasculature. As collagen accumulates, the tissue stiffens, disrupting the paracrine signals that folliculogenesis depends on. Previous work has shown that age-associated collagen buildup and fibroblast senescence impair this communication, and, crucially, that interventions which remove fibrotic collagen from the mouse ovary can restore ovulation and extend reproductive lifespan. Fibrosis, in other words, may not simply be a scar left behind by ovarian aging; it may be an upstream driver of it.

The new study adds a dietary dimension to that framework. Alongside collagen, the researchers measured lipofuscin, the indigestible sludge of oxidized proteins and lipids that accumulates in senescent cells and is increasingly recognized as an early marker of ovarian aging. Western diet mice showed significantly more lipofuscin than controls, with the other dietary groups falling in between. Macrophage infiltration, assessed by CD68 immunofluorescence, trended upward in the dietary intervention groups but did not reach statistical significance, leaving the inflammatory component of the remodeling an open question for future work with larger samples.

What the diets did not do is equally informative. Follicle counts across primordial, transitional, secondary, and tertiary categories were largely preserved, and the total number of oocytes ovulated after hormonal superovulation was unchanged. Fluorescent staining of isolated oocytes for lipid content and mitochondrial activity showed no detectable differences across the groups. The only follicular exception was a reduced number of primary follicles in the high-fat diet mice, hinting at diminished follicle survival rather than a wholesale collapse of the reserve. Oocyte quality endpoints such as meiotic spindle integrity and embryo development were not assessed, so subtle damage cannot be ruled out, but on the measures taken, the germ cell compartment looked remarkably resilient while the tissue around it visibly changed.

Reproductive cycling told a more nuanced story. Mice on the full Western diet spent more time in metaestrus and had significantly shorter estrous cycles than controls, a pattern the authors interpret as possible dysregulation of the hypothalamic-pituitary-ovarian axis rather than heightened reproductive activity. The observation echoes human data: short-term high-fat feeding in normal-weight women suppresses luteinizing hormone secretion, and high-glycemic diets are associated with ovulatory disorders, while low-glycemic diets improve menstrual regularity in polycystic ovary syndrome. All three intervention groups in the mouse study also showed elevated fasting glucose, and chronic hyperglycemia is known to disrupt GnRH pulsatility and provoke ovarian inflammation. Because circulating reproductive hormones were not measured, direct endocrine proof is still missing, but the concordance between shortened cycles, elevated glucose, and stromal fibrosis in the Western diet group is suggestive.

The study’s limitations are acknowledged candidly by its authors. Seventeen weeks in young mice is a short window, there was no aged comparator group to separate diet effects from physiological aging, and the single-timepoint design cannot establish whether fibrotic remodeling precedes or follows the metabolic disturbances. Histology was not backed by molecular quantification of extracellular matrix genes or biochemical collagen assays. And because the mice were middle-aged rather than near the end of reproductive life, longer interventions might yet reveal follicular depletion that this experiment could not capture. These caveats temper but do not diminish the central message: the stromal compartment responds to dietary stress earlier and more visibly than the follicles it supports.

The translational horizon is where the findings become genuinely exciting. If ovarian fibrosis is an early and modifiable feature of reproductive decline, then metabolic interventions could plausibly protect fertility. GLP-1 receptor agonists such as semaglutide, already reshaping the treatment of obesity and metabolic disease, may mitigate the upstream conditions that drive ovarian remodeling, and early clinical studies are examining their effects on reproductive outcomes in women with obesity. On the tissue side, the anti-fibrotic drug pirfenidone has been shown in reproductively aged and obese mice to reduce ovarian collagen deposition and improve ovulatory function. The Brazilian team’s work strengthens the case that reproductive aging is not merely a countdown written in the genome but a metabolically responsive process, one in which the food environment writes the earliest chapters, and in which the stroma, not the egg, may hold the first editable draft.

Subject of Research: How dietary composition and metabolic stress reshape the aging ovarian microenvironment in mice

Article Title: Dietary composition and metabolic stress differentially affect the ovarian microenvironment in mice

Article References: da Cunha Pereira, G., Pereira, T. H. L., Prosczek, J. B., Magalhães, L. S., Pinzón-Osorio, C. A., Nogueira, Â. G. A., Hense, J. D., Zanini, B. M., Garcia, D. N., Mondadori, R. G., Vaucher, R. A., & Schneider, A. (2026). Dietary composition and metabolic stress differentially affect the ovarian microenvironment in mice. GeroScience. https://doi.org/10.1007/s11357-026-02530-2

Image Credits: AI Generated

DOI: 10.1007/s11357-026-02530-2

Keywords: ovarian aging, ovarian fibrosis, Western diet, high-fat diet, ovarian reserve, stromal collagen, lipofuscin, estrous cycle, insulin resistance, reproductive longevity, extracellular matrix, GeroScience