Researchers have traced how the molecular byproducts of active DNA demethylation change across the human lifespan, comparing measurements in urine with measurements in DNA extracted from leukocytes. The study, published as a research article in Biological Research, analyzed samples from healthy volunteers aged between 1.5 and 71 years.
Because DNA methylation changes are recognized as a key hallmark of biological aging, the team set out to determine whether the products of this demethylation pathway shift measurably with age in both cellular DNA and urine.
The results showed a consistent pattern: in urine, the levels of the analyzed modifications declined with age. The researchers reported statistically significant inverse correlations between age and urinary levels of 5-hydroxymethyluracil, 5-hydroxymethylcytosine, 5-(hydroxymethyl)-2′-deoxycytidine, 5-methyl-2′-deoxycytidine, 5-carboxycytosine, and 5-formylcytosine.
Among these, the strongest association was observed for 5-hydroxymethyluracil, which showed a correlation coefficient of r = −0.66 with age. Among the analyzed urinary modifications, 5-hydroxymethyluracil showed the strongest inverse association with age in this cohort, making it the most age-correlated of the measured demethylation products.
In DNA isolated from leukocytes, the age-related pattern was narrower. Statistically significant inverse correlations with age were found for only two of the analyzed modifications, 5-(hydroxymethyl)-2′-deoxycytidine and 5-methyl-2′-deoxycytidine, both decreasing with age.
The authors concluded that changes in these epigenetic modifications with age are more pronounced in urine than in cellular DNA. This contrast suggests that urine may capture a broader, body-wide signal of demethylation activity, whereas measurements from leukocyte DNA reflect changes confined to a single cell type.
The study itself frames this difference as an important limitation and advantage at once: DNA modifications detected in blood are limited to one tissue, leukocytes, whereas modifications excreted into urine reflect processes occurring at the level of the entire organism. In other words, urinary measurements may integrate demethylation activity from many tissues, while leukocyte DNA offers only a window into blood immune cells.
Because the article was shared early as a peer-reviewed, accepted manuscript, the published version notes that it is subject to further edits before the final Version of Record appears.
The strongest single signal, 5-hydroxymethyluracil in urine, suggests that specific demethylation byproducts could serve as indicators of systemic epigenetic change with age, though the reported correlations describe associations between age and measured levels rather than changes tracked over time within the same people.
Subject of Research: Age-related changes in active DNA demethylation pathway products measured in urine and leukocyte DNA
Article Title: Age-related changes in the levels of active DNA demethylation pathway products in urine and in DNA isolated from leukocytes
Article References: Lesniewski, F., Skalska-Bugala, A., Starczak, M., Guz, J., Zarakowska, E., Wasilow, A., Mijewski, P., Siomek-Gorecka, A., Koltan, A., Linowiecka, K., Banaszkiewicz, Z., Gackowski, D., Olinski, R., & Rozalski, R. (2026). Age-related changes in the levels of active DNA demethylation pathway products in urine and in DNA isolated from leukocytes. Biological Research. https://doi.org/10.1186/s40659-026-00733-7
Image Credits: AI Generated
DOI: 10.1186/s40659-026-00733-7
Keywords: DNA demethylation, epigenetics, aging, 5-hydroxymethyluracil, urine biomarkers, leukocytes, DNA methylation, 5-methyl-2'-deoxycytidine, biological aging, biomarkers, Age-related, changes
News Source: Beatrice Stafford. (October 28, 2026). Urine may reveal aging-related DNA demethylation changes better than leukocytes. Scienmag.
