Blood biomarker study points to new aging tool across species

Researchers at the German Center for Neurodegenerative Diseases and the Hertie Institute for Clinical Brain Research reported that neurofilament light chain, or NfL, a blood marker already used in human neurodegeneration research, may also help track aging across species. In a PLOS Biology study published in February 2026, the team analyzed blood samples from 862 animals across 57 species and found that NfL increased with age in mice, cats, dogs, and horses, with trajectories that resembled those seen in humans. In a longitudinal mouse cohort, faster increases in NfL were also linked to shorter remaining lifespan. The researchers say the marker could eventually help assess biological age and mortality risk in animals. (eurekalert.org)

Why it matters: For veterinary professionals, the finding adds to a growing body of evidence that blood-based neurologic biomarkers may have practical value beyond research settings. Prior canine studies have already linked circulating NfL to neurodegeneration and cognitive dysfunction, and recent veterinary literature has suggested these biomarkers could complement clinical assessment and imaging, even though they remain only marginally used in practice today. The new cross-species data broadens that conversation, especially for senior pet care, comparative medicine, and future monitoring of aging interventions, but the authors also note an important limitation: many samples came from diagnostic labs, so undetected illness could have influenced NfL values. (pmc.ncbi.nlm.nih.gov)

What to watch: Watch for follow-up work that establishes species-specific reference ranges, validates the marker in healthier prospective cohorts, and clarifies whether NfL can move from a promising research tool into routine veterinary use. (pmc.ncbi.nlm.nih.gov)