The cerebral biomarkers, neurofilament light chain (NfL), amyloid-β, tau, and neuron specific enolase (NSE) reflect a wide spectrum of neurological damage in the brain and spinal cord. With this study, we aimed to assess whether these biomarkers hold any potential diagnostic value for the three most common canine neurological diseases. Canines suffering from meningoencephalitis of unknown origin (MUO), brain tumors, and selected non-infectious myelopathies were included. For each diagnosis, we analyzed these biomarkers in the cerebrospinal fluid collected via cranial puncture from the cisterna magna. Elevated levels of CSF tau, NfL, and NSE were observed in MUO, with all three biomarkers being intercorrelated. Tau and NSE were increased while amyloid-β was decreased in dogs suffering from tumors. In contrast, no biomarker changes were observed in dogs with myelopathies. Covariates such as age, sex, or castration had minimal impact. CSF biomarkers may reflect molecular changes related to MUO and tumors, but not to non-infectious myelopathies. The combination of NfL, tau, and NSE may represent useful biomarkers for MUO as they reflect the same pathology and are not influenced by age.

Axon Neuroscience R and D Services SE Dvořakovo Nabrezie 10 Bratislava Slovak Republic

Institute of Mathematics and Statistics Masaryk University Kotlářská 267 2 611 37 Brno Czech Republic

Institute of Neuroimmunology Slovak Academy of Sciences Dúbravská Cesta 9 Bratislava Slovak Republic

Neuroimmunology Institute n p o Dvořákovo nábrežie 7527 10 811 02 Bratislava Slovak Republic

Neurovet Referral Center for Veterinary Neurology Bratislavska 2196 32 Trencin Slovak Republic

Small Animal Referral Centre Sibra Na Vrátkach 13 Bratislava Slovak Republic

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Sisó, S. et al. Neurodegenerative diseases in domestic animals: A comparative review. Vet. J.171(1), 20–38 (2006). PubMed

Noble, W. & Burns, M. Challenges in neurodegeneration research. Front. Psychiatry10.3389/fpsyt.2010.00007 (2010). PubMed PMC

Prpar Mihevc, S. & Majdič, G. Canine cognitive dysfunction and Alzheimer’s disease—Two facets of the same disease?. Front. Neurosci.10.3389/fnins.2019.00604 (2019). PubMed PMC

Lombardi, G. et al. Structural magnetic resonance imaging for the early diagnosis of dementia due to Alzheimer’s disease in people with mild cognitive impairment. Cochrane Database Syst. Rev.3(3), CD009628 (2020). PubMed PMC

Cullen, N. C. et al. Efficacy assessment of an active tau immunotherapy in Alzheimer’s disease patients with amyloid and tau pathology: A post hoc analysis of the “ADAMANT” randomised, placebo-controlled, double-blind, multi-centre, phase 2 clinical trial. EBioMedicine99, 104923 (2024). PubMed PMC

Salloway, S. et al. Two phase 3 trials of bapineuzumab in mild-to-moderate Alzheimer’s disease. N. Engl. J. Med.370(4), 322–333 (2014). PubMed PMC

Janelidze, S. et al. Head-to-head comparison of 10 plasma phospho-tau assays in prodromal Alzheimer’s disease. Brain146(4), 1592–1601 (2023). PubMed PMC

Lowrie, M., Smith, P. M. & Garosi, L. Meningoencephalitis of unknown origin: Investigation of prognostic factors and outcome using a standard treatment protocol. Vet. Rec.172(20), 527 (2013). PubMed

Cornelis, I. et al. Clinical presentation, diagnostic findings, prognostic factors, treatment and outcome in dogs with meningoencephalomyelitis of unknown origin: A review. Vet. J.244, 37–44 (2019). PubMed

Lowrie, M. et al. Effect of a constant rate infusion of cytosine arabinoside on mortality in dogs with meningoencephalitis of unknown origin. Vet. J.213, 1–5 (2016). PubMed

Hall, S. et al. CSF biomarkers and clinical progression of Parkinson disease. Neurology84(1), 57–63 (2015). PubMed PMC

Blennow, K. & Zetterberg, H. Chapter one—Fluid biomarker-based molecular phenotyping of Alzheimer’s disease patients in research and clinical settings. In Progress in Molecular Biology and Translational Science (ed. Teplow, D. B.) 3–23 (Academic Press, 2019). PubMed

Blennow, K. & Zetterberg, H. Biomarkers for Alzheimer’s disease: Current status and prospects for the future. J. Intern. Med.284(6), 643–663 (2018). PubMed

Jack, C. R. Jr. et al. NIA-AA research framework: Toward a biological definition of Alzheimer’s disease. Alzheimers Dement.14(4), 535–562 (2018). PubMed PMC

Lleó, A. et al. Longitudinal cerebrospinal fluid biomarker trajectories along the Alzheimer’s disease continuum in the BIOMARKAPD study. Alzheimers Dement.15(6), 742–753 (2019). PubMed

Bittner, S. et al. The potential of serum neurofilament as biomarker for multiple sclerosis. Brain144(10), 2954–2963 (2021). PubMed PMC

Olby, N. J. et al. Prognostic factors in canine acute intervertebral disc disease. Front. Vet. Sci.7, 596059 (2020). PubMed PMC

Roerig, A. et al. Cerebrospinal fluid tau protein as a biomarker for severity of spinal cord injury in dogs with intervertebral disc herniation. Vet. J.197(2), 253–258 (2013). PubMed

Toda, Y. et al. Glial fibrillary acidic protein (gfap) and anti-gfap autoantibody in canine necrotising meningoencephalitis. Vet. Record161(8), 261–264 (2007). PubMed

Toedebusch, C. M. et al. Cerebrospinal fluid levels of phosphorylated neurofilament heavy as a diagnostic marker of canine degenerative myelopathy. J. Vet. Intern. Med.31(2), 513–520 (2017). PubMed PMC

Panek, W. K. et al. Plasma neurofilament light chain as a translational biomarker of aging and neurodegeneration in dogs. Mol. Neurobiol.57(7), 3143–3149 (2020). PubMed PMC

Yun, T. et al. Neurofilament light chain as a biomarker of meningoencephalitis of unknown etiology in dogs. J. Vet. Intern. Med.35(4), 1865–1872 (2021). PubMed PMC

Zhang, L. et al. Cerebrospinal fluid and blood biomarkers in the diagnostic assays of Alzheimer’s disease. J. Innov. Opt. Health Sci.15(01), 2230001 (2022).

Olby, N. J. et al. Time course and prognostic value of serum GFAP, pNFH, and S100beta concentrations in dogs with complete spinal cord injury because of intervertebral disc extrusion. J. Vet. Intern. Med.33(2), 726–734 (2019). PubMed PMC

Vikartovska, Z. et al. Novel diagnostic tools for identifying cognitive impairment in dogs: Behavior, biomarkers, and pathology. Front. Vet. Sci.7, 551895 (2020). PubMed PMC

Samanci, Y. et al. Neuron-specific enolase levels as a marker for possible neuronal damage in idiopathic intracranial hypertension. Acta Neurol. Belg.117(3), 707–711 (2017). PubMed

Granger, N., Smith, P. M. & Jeffery, N. D. Clinical findings and treatment of non-infectious meningoencephalomyelitis in dogs: A systematic review of 457 published cases from 1962 to 2008. Vet. J.184(3), 290–297 (2010). PubMed

Hecht, S. & Adams, W. H. MRI of brain disease in veterinary patients part 2: Acquired brain disorders. Vet. Clin. North Am. Small Anim. Pract.40(1), 39–63 (2010). PubMed

Wisner, E. R., Dickinson, P. J. & Higgins, R. J. Magnetic resonance imaging features of canine intracranial neoplasia. Vet. Radiol. Ultrasound52(1 Suppl 1), S52-61 (2011). PubMed

Rusbridge, C., Greitz, D. & Iskandar, B. J. Syringomyelia: Current concepts in pathogenesis, diagnosis, and treatment. J. Vet. Intern. Med.20(3), 469–479 (2006). PubMed

Hechler, A. C. & Moore, S. A. Understanding and treating chiari-like malformation and syringomyelia in dogs. Top. Companion Anim. Med.33(1), 1–11 (2018). PubMed

Mariani, C. L. et al. Cerebrospinal fluid lactate in dogs with inflammatory central nervous system disorders. J. Vet. Intern. Med.33(6), 2701–2708 (2019). PubMed PMC

De Risio, L. et al. International veterinary epilepsy task force consensus proposal: Diagnostic approach to epilepsy in dogs. BMC Vet. Res.11, 148 (2015). PubMed PMC

Di Terlizzi, R. & Platt, S. R. The function, composition and analysis of cerebrospinal fluid in companion animals: Part II—Analysis. Vet. J.180(1), 15–32 (2009). PubMed

MacNeill, A. L. et al. The effects of iatrogenic blood contamination on total nucleated cell counts and protein concentrations in canine cerebrospinal fluid. Vet. Clin. Pathol.47(3), 464–470 (2018). PubMed

Nagendran, A. et al. Risk factors for blood-contaminated cerebrospinal fluid collection in dogs. Vet. Rec.186(16), e8 (2020). PubMed

Hurtt, A. E. & Smith, M. O. Effects of iatrogenic blood contamination on results of cerebrospinal fluid analysis in clinically normal dogs and dogs with neurologic disease. J. Am. Vet. Med. Assoc.211(7), 866–867 (1997). PubMed

Chrisman, C. L. Cerebrospinal fluid analysis. Vet. Clin. North Am. Small Anim. Pract.22(4), 781–810 (1992). PubMed

Hugo, T. B., Heading, K. L. & Labuc, R. H. Canine cerebrospinal fluid total nucleated cell counts and cytology associations with the prevalence of magnetic resonance imaging abnormalities. Vet. Med. (Auckl)5, 75–84 (2014). PubMed PMC

R_Core_Team. R: A language and environment for statistical computing (R Foundation for Statistical Computing, 2022).

Welch, B. L. The generalization of `student’s’ problem when several different population variances are involved. Biometrika34(1/2), 28–35 (1947). PubMed

Searle, S. R., Speed, F. M. & Milliken, G. A. Population marginal means in the linear model: An alternative to least squares means. Am. Stat.34(4), 216–221 (1980).

Winterbottom, A. A note on the derivation of fisher’s transformation of the correlation coefficient. Am. Stat.33(3), 142–143 (1979).

Pepe, M. S. The Statistical Evaluation of Medical Tests for Classification and Prediction (Oxford University Press, 2004).

Stylianaki, I. et al. Amyloid-beta plasma and cerebrospinal fluid biomarkers in aged dogs with cognitive dysfunction syndrome. J. Vet. Intern. Med.34(4), 1532–1540 (2020). PubMed PMC

Smolek, T. et al. Tau hyperphosphorylation in synaptosomes and neuroinflammation are associated with canine cognitive impairment. J. Compar. Neurol.524(4), 874–895 (2016). PubMed

National Center for Biotechnology Information Database (NCBI).

Blomme, E. A. G. & Waring, J. F. Cerebrospinal fluid biomarkers: Exploiting advances in humans to improve veterinary care. Vet. J.197(2), 113–114 (2013). PubMed

Isgrò, M. A., Bottoni, P. & Scatena, R. Neuron-specific enolase as a biomarker: Biochemical and clinical aspects. In Advances in Cancer Biomarkers: From biochemistry to clinic for a critical revision (ed. Scatena, R.) 125–143 (Springer, 2015). PubMed

Bandyopadhyay, S. et al. Serum neuron-specific enolase as a predictor of short-term outcome in children with closed traumatic brain injury. Acad. Emerg. Med.12(8), 732–738 (2005). PubMed

Selakovic, V., Raicevic, R. & Radenovic, L. The increase of neuron-specific enolase in cerebrospinal fluid and plasma as a marker of neuronal damage in patients with acute brain infarction. J. Clin. Neurosci.12(5), 542–547 (2005). PubMed

El-Maraghi, S. et al. The prognostic value of neuron specific enolase in head injury. Egypt. J. Crit. Care Med.1(1), 25–32 (2013).

Nakamura, K. et al. Proteome analysis of cerebrospinal fluid in healthy beagles and canine encephalitis. J. Vet. Med. Sci.74(6), 751–756 (2012). PubMed

Satoh, H. et al. Cerebrospinal fluid biomarkers showing neurodegeneration in dogs with GM1 gangliosidosis: Possible use for assessment of a therapeutic regimen. Brain Res.1133, 200–208 (2007). PubMed

Elias, B. C., Alfieri, A. F., Navarro, I. T. & Gomes, L. A. Neuron-specific enolase as biomarker for possible neuronal damage in dogs with distemper vírus. Pesquisa Veterinária Brasileira39(01), 47–51 (2019).

Gaetani, L. et al. Neurofilament light chain as a biomarker in neurological disorders. J. Neurol. Neurosurg. Psychiatry90(8), 870–881 (2019). PubMed

Head, E. et al. Amyloid-β peptide and oligomers in the brain and cerebrospinal fluid of aged canines. J. Alzheimer’s Dis.20, 637–646 (2010). PubMed PMC

Urfer, S. R. et al. Canine Cognitive Dysfunction (CCD) scores correlate with amyloid beta 42 levels in dog brain tissue. GeroScience43(5), 2379–2386 (2021). PubMed PMC

Schmidt, F. et al. Detection and quantification of β-amyloid, pyroglutamyl Aβ, and tau in aged canines. J. Neuropathol. Exp. Neurol.74(9), 912–923 (2015). PubMed

Rusbridge, C. et al. An aged canid with behavioral deficits exhibits blood and cerebrospinal fluid amyloid beta oligomers. Front. Aging Neurosci.10.3389/fnagi.2018.00007 (2018). PubMed PMC

Borghys, H. et al. Young to middle-aged dogs with high amyloid-β levels in cerebrospinal fluid are impaired on learning in standard cognition tests. J. Alzheimer’s Dis.56(2), 763–774 (2017). PubMed PMC

Priester, W. A. & Mantel, N. Occurrence of tumors in domestic animals. Data from 12 United States and Canadian colleges of veterinary medicine. J. Natl. Cancer Inst.47(6), 1333–44 (1971). PubMed

Song, R. B. et al. Postmortem evaluation of 435 cases of intracranial neoplasia in dogs and relationship of neoplasm with breed, age, and body weight. J. Vet. Intern. Med.27(5), 1143–1152 (2013). PubMed

Snyder, J. M. et al. Canine intracranial primary neoplasia: 173 cases (1986–2003). J. Vet. Intern. Med.20(3), 669–675 (2006). PubMed

Westworth, D. et al. Choroid plexus tumors in 56 dogs (1985–2007). J. Vet. Intern. Med.22(5), 1157–1165 (2008). PubMed

Sturges, B. et al. Magnetic resonance imaging and histological classification of intracranial meningiomas in 112 dogs. J. Vet. Intern. Med.22(3), 586–595 (2008). PubMed

Miller, A. D., Miller, C. R. & Rossmeisl, J. H. Canine primary intracranial cancer: A clinicopathologic and comparative review of glioma, meningioma, and choroid plexus tumors. Front. Oncol.10.3389/fonc.2019.01151 (2019). PubMed PMC

Wolff, C. A. et al. Magnetic resonance imaging for the differentiation of neoplastic, inflammatory, and cerebrovascular brain disease in dogs. J. Vet. Intern. Med.26(3), 589–597 (2012). PubMed

Bentley, R. T. Magnetic resonance imaging diagnosis of brain tumors in dogs. Vet. J.205(2), 204–216 (2015). PubMed

Braund, K. G. Granulomatous meningoencephalomyelitis. J. Am. Vet. Med. Assoc.186(2), 138–141 (1985). PubMed

Tipold, A. Diagnosis of inflammatory and infectious diseases of the central nervous system in dogs: A retrospective study. J. Vet. Intern. Med.9(5), 304–314 (1995). PubMed

Coates, J. R. & Jeffery, N. D. Perspectives on meningoencephalomyelitis of unknown origin. Vet. Clin. North Am. Small Anim. Pract.44(6), 1157–1185 (2014). PubMed

Talarico, L. R. & Schatzberg, S. J. Idiopathic granulomatous and necrotising inflammatory disorders of the canine central nervous system: A review and future perspectives. J. Small Anim. Pract.51(3), 138–149 (2010). PubMed

Nessler, J. N. et al. Canine meningoencephalitis of unknown origin-the search for infectious agents in the cerebrospinal fluid via deep sequencing. Front. Vet. Sci.8, 645517 (2021). PubMed PMC

Wijnrocx, K. et al. Twelve years of chiari-like malformation and syringomyelia scanning in Cavalier King Charles Spaniels in the Netherlands: Towards a more precise phenotype. PLoS One12(9), e0184893 (2017). PubMed PMC

Mitchell, T. J. et al. Syringomyelia: Determining risk and protective factors in the conformation of the Cavalier King Charles Spaniel dog. Canine Genet. Epidemiol.1(1), 9 (2014). PubMed PMC

Park, C. et al. Syringomyelia in three small breed dogs secondary to Chiari-like malformation: Clinical and diagnostic findings. J. Vet. Sci.10(4), 365–367 (2009). PubMed PMC

Wolfe, K. C. & Poma, R. Syringomyelia in the Cavalier King Charles spaniel (CKCS) dog. Can. Vet. J.51(1), 95–102 (2010). PubMed PMC

Rusbridge, C., McFadyen, A. K. & Knower, S. P. Behavioral and clinical signs of Chiari-like malformation-associated pain and syringomyelia in Cavalier King Charles spaniels. J. Vet. Intern. Med.33(5), 2138–2150 (2019). PubMed PMC

Knowler, S. P., Galea, G. L. & Rusbridge, C. Morphogenesis of Canine chiari malformation and secondary syringomyelia: Disorders of cerebrospinal fluid circulation. Front. Vet. Sci.5, 171 (2018). PubMed PMC

Rusbridge, C., Stringer, F. & Knowler, S. P. Clinical application of diagnostic imaging of Chiari-like malformation and syringomyelia. Front. Vet. Sci.5, 280 (2018). PubMed PMC

Rusbridge, C. & Knowler, S. P. Inheritance of occipital bone hypoplasia (Chiari type I malformation) in Cavalier King Charles Spaniels. J. Vet. Intern. Med.18(5), 673–678 (2004). PubMed

Lu, D. et al. Neurological signs and results of magnetic resonance imaging in 40 cavalier King Charles spaniels with Chiari type 1-like malformations. Vet. Record153(9), 260–263 (2003). PubMed

Griffin, J. F. et al. Meningomyelitis in dogs: A retrospective review of 28 cases (1999 to 2007). J. Small Anim. Pract.49(10), 509–517 (2008). PubMed

Tipold, A. & Stein, V. M. Inflammatory diseases of the spine in small animals. Vet. Clin. North Am. Small Anim. Pract.40(5), 871–879 (2010). PubMed

Wojdala, A. L. et al. Trajectories of CSF and plasma biomarkers across Alzheimer’s disease continuum: Disease staging by NF-L, p-tau181, and GFAP. Neurobiol. Dis.189, 106356 (2023). PubMed

Rostgaard, N. et al. Differential proteomic profile of lumbar and ventricular cerebrospinal fluid. Fluids Barriers CNS20(1), 6 (2023). PubMed PMC