The protein known as neurofilament light chain (NfL) has long been studied in humans as a biomarker closely linked to neurodegenerative diseases and the aging process. Recent findings from leading researchers at the German Center for Neurodegenerative Diseases (DZNE) and the Hertie Institute for Clinical Brain Research (HIH) at the University of Tübingen demonstrate that NfL is not exclusive to humans. Intriguingly, it is detectable in the bloodstream of a wide array of animal species, and its levels increase progressively with age in mice, cats, dogs, and horses. This discovery suggests a promising avenue for assessing biological aging and estimating life expectancy across species, with profound implications for veterinary medicine and comparative neurobiology.
Neurofilament light chain serves as a critical structural component of neurons, forming part of the cytoskeletal network within axons. Under conditions of neuronal stress, damage, or degeneration—common in various neurological disorders and aging—NfL is released into the extracellular space and eventually enters the bloodstream. The detection of NfL in plasma or serum has emerged as a sensitive technique for evaluating neuronal integrity and neurodegeneration. In the context of human health, elevated NfL levels appear in diseases such as Alzheimer’s disease and amyotrophic lateral sclerosis (ALS), while gradually rising baseline levels correspond to the normal aging process.
Exploring this phenomenon beyond human subjects, Prof. Mathias Jucker, a research group leader at DZNE and HIH, and his team have documented that NfL plasma concentrations exhibit a remarkably similar pattern in various animal species, including commonly domesticated and laboratory animals. By examining aged cohorts of mice, cats, dogs, and horses, they established consistent age-associated increases in blood NfL levels. These findings raise the possibility that NfL functions as a universal biomarker of neurological aging, conserved across mammalian species despite differences in life spans and physiology.
Further deepening the significance of NfL’s utility, the team carried out longitudinal observations in a cohort of 44 elderly mice, monitoring their blood NfL levels systematically over a four-month period. Strikingly, individuals exhibiting a slower rate of increase in NfL concentrations tended to enjoy longer lifespans, whereas those with rapid elevations faced diminished survival. This correlation between NfL dynamics and mortality risk mirrors similar epidemiological data reported in aging human populations, where NfL levels predict all-cause mortality, suggesting that the trajectory of neurofilament accumulation is not merely a biomarker but holds predictive power over biological aging and viability.
The study extended its scale by sampling 53 diverse animal species, ranging from other mammals such as rabbits, lions, and monkeys to reptiles and birds, in collaboration with institutions such as the Stuttgart Zoo and the Vetsuisse Faculty at the University of Zurich. While NfL protein was consistently detectable in the blood of all mammals studied, it appeared less frequently in non-mammalian species. For example, some reptiles and birds like crocodiles and parrots showed detectable NfL, although differences in the protein’s amino acid sequence across taxa may reduce assay sensitivity, necessitating customized detection methods in future research.
These cross-species insights reveal the translational potential of NfL measurement, originally developed in dementia and neurological disease research, into the realm of veterinary diagnostics. Neurologically driven aging and health decline likely share conserved pathological mechanisms reflected by NfL release, making this biomarker an invaluable tool for assessing neurological health status, biological age, and potential lifespan in animals. This could revolutionize animal care, enabling early identification of neurodegenerative conditions and improving life expectancy predictions across a vast taxonomic spectrum.
The technical backbone of this research hinges on the use of highly sensitive immunoassays capable of quantifying minute concentrations of NfL in blood samples. These assays detect epitopes on the protein’s structure, which, given evolutionary variations, may sometimes limit detection in certain species. Overcoming these limitations may involve developing species-specific antibodies or employing mass spectrometry-based methods to broaden the spectrum of identifiable NfL variants. The meticulous analytical rigor in this research ensures reliable quantification, essential for establishing meaningful correlations between NfL levels and physiological aging metrics.
Neurodegenerative diseases like Alzheimer’s and ALS remain global health challenges, their pathological mechanisms intricately tied to neurofilament disruption. Biomedical research into biomarkers such as NfL provides insights not only for human clinical purposes but also offers blueprints for comparative aging studies. The demonstration that similar neurodegenerative biomarkers apply to animals closes gaps between human medicine and veterinary science, fostering integrative approaches to aging and neurological disease management.
Experts underscore that understanding the neurobiological aging process at the molecular and cellular level contributes to broader strategies for healthy aging interventions. Biomarkers like NfL enable objective measurement of neuronal damage over time, a critical step in monitoring disease progression or the effectiveness of therapeutic interventions. The identification of blood-based biomarkers that function consistently across species introduces potent new tools for research and applied veterinary medicine, with implications for enhancing animal welfare and extending healthy life spans.
In addition, the ability to estimate life expectancy noninvasively through blood NfL measurement offers valuable applications in conservation biology and zoological management. For endangered species or animals in captivity, such accurate biomarkers facilitate longitudinal health monitoring, guiding care decisions and breeding programs. This innovation also responds to a pressing need within veterinary diagnostics for objective, easily accessible indicators of aging and neurodegeneration beyond symptomatic observation.
Moving forward, integrating NfL assessments into routine veterinary practice could dramatically alter paradigms of animal healthcare. Regular blood tests measuring NfL could become standard wellness checks, enabling preemptive interventions before the emergence of overt neurological symptoms. Alongside other clinical markers and imaging studies, NfL quantification builds a comprehensive picture of neurological health status, empowering veterinarians and animal caretakers with precise evaluative tools.
This pioneering research heralds a new era of cross-disciplinary collaboration, where methodologies from human dementia research inform and enrich animal health sciences. The DZNE and HIH teams exemplify this translational research ethos, advancing understanding of aging as a shared biological phenomenon. As the scientific community continues to decode the complexities of neurodegeneration and biological timekeeping, biomarkers like neurofilament light chain will likely become cornerstones of both human and veterinary medicine.
Ultimately, the recognition that neurofilament light chain is a conserved, measurable biomarker presenting consistent age-related changes across mammals ushers in transformative prospects. From basic research on neuronal integrity to practical applications in veterinary health and lifespan prediction, NfL holds the promise to bridge species divides, illuminating shared biological aging pathways and fostering innovations that benefit patients and animals alike.
Subject of Research: Animals
Article Title: Neurofilament light chain may serve as a cross-species blood biomarker to assess aging and predict mortality
News Publication Date: 19-Feb-2026
Web References: http://dx.doi.org/10.1371/journal.pbio.3003606
Keywords: Biomarkers, Neuroscience, Neurodegenerative diseases, Life expectancy, Veterinary medicine
Tags: biological age estimation methodsblood biomarkers for agingcomparative neurobiology researchcross-species aging indicatorsneurodegeneration in petsneurodegenerative disease markersneurofilament light chain biomarkerneuronal damage detectionplasma NfL levels in mammalsprotein biomarkers in agingtracking aging in animalsveterinary neurodegenerative diagnostics
