In 78 mouse blood and liver samples, youthful circulation lined up with a reversal of age-related methylation

What the research found

A reanalysis was published on 12 November 2026. Igor Kovalchuk and Olga Kovalchuk used processed reduced-representation bisulfite sequencing from a published prolonged heterochronic parabiosis experiment. The set was 78 blood and liver samples from old mice. This is a mouse methylation study, with no human age or sex split in the abstract, so the tags are all and all ages. Across 1,008,133 CpG sites with at least 10-fold coverage in every sample, methylation changes after pairing with a young circulation ran opposite to normal aging in blood and liver. At a 10 percentage point threshold, 22,424 blood CpGs and 22,286 liver CpGs were reversed right after the pairing, and 1,792 were the same loci. After two months, 25,867 blood CpGs and 15,437 liver CpGs were reversed, with 1,387 shared loci. A 64-CpG cross-tissue core persisted at both times. Reversed sites were scarce in promoters and CpG islands and more common in gene bodies. After shared sites were removed, nearest-gene convergence was 4,716 observed versus 4,215 expected (empirical P near 0.001). Stricter models did not support promoter or Gene Ontology convergence. A reanalysis of an existing mouse experiment, not a human trial. DOI 10.1093/gerona/glag258. Not medical advice.

Evidence level: Animal study. Results in animals or cells often don't carry over to people.

Read the original at The Journals of Gerontology, Series A