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Pandit PS, Smith WA, Finno CJ, Aleman M, Conrad PA, Packham A, Plancarte M, Woolard K, Marsh A, Pusterla N. A fresh look at the SarcoFluor antibody test for the detection of specific antibodies to Sarcocystis neurona for the diagnosis of equine protozoal myeloencephalitis. Vet Parasitol 2024; 330:110219. [PMID: 38897057 DOI: 10.1016/j.vetpar.2024.110219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 05/31/2024] [Accepted: 06/01/2024] [Indexed: 06/21/2024]
Abstract
Equine protozoal myeloencephalitis (EPM) is a challenging disease to diagnose in horses with neurological signs. To optimize contemporary diagnostic testing, including the use of serum:CSF antibody ratios, the SarcoFluor antibody test for Sarcocystis neurona requires revalidation. The SarcoFluor, a previously validated immunofluorescent antibody test (IFAT) for the detection of antibodies specific to S. neurona in serum and cerebrospinal fluid (CSF) of naturally infected horses was analyzed using recent data and considering a serum:CSF antibody ratio threshold. Utilization of serum and CSF phosphorylated neurofilament heavy protein (pNfH) concentrations in support of an EPM diagnosis was also evaluated. 172 horses were divided into three groups: EPM-positive horses (EPM+, n=42), neurological non-EPM horses (n=74) confirmed with non-EPM neurological diseases (cervical vertebral compressive myelopathy, equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy), and control horses (control, n=56) without neurological signs and neurological abnormalities on histology. Logistic regression was used to compare EPM diagnostic regimens. Specifically, EPM+ horses were compared with neurological non-EPM horses showing neurological signs. To consider diagnostic utility, post-test probabilities were calculated by titer. When differentiating between EPM and other neurological diseases, the combination of serum and CSF SarcoFluor testing added more information to the model accuracy than either test alone. Using serum and CSF for pNfH in support of an EPM diagnosis did not identify cutoffs with statistically significant odds ratios but increased the overall model accuracy when used with the IFAT. Utilization of IFAT titers against S. neurona in serum and CSF result in a high post-test probability of detecting EPM+ horses in a clinical setting.
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Affiliation(s)
- Pranav S Pandit
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California Davis, One Shields Avenue, Davis, CA 95616, USA.
| | - Woutrina A Smith
- One Health Institute, School of Veterinary Medicine, University of California, 1089 Veterinary Medicine Drive, VM3B, Davis, CA 95616, USA
| | - Carrie J Finno
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Monica Aleman
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California Davis, Tupper Hall 2108, One Shields Avenue, Davis, CA 95616, USA
| | - Patricia A Conrad
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, 1 Shields Avenue, Davis, CA, 95616, USA
| | - Andrea Packham
- One Health Institute, School of Veterinary Medicine, University of California, 1089 Veterinary Medicine Drive, VM3B, Davis, CA 95616, USA
| | - Magdalena Plancarte
- One Health Institute, School of Veterinary Medicine, University of California, 1089 Veterinary Medicine Drive, VM3B, Davis, CA 95616, USA
| | - Kevin Woolard
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, 1 Shields Avenue, Davis, CA, 95616, USA
| | - Antoinette Marsh
- Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University, 1920 Coffey Road, Columbus, OH, USA
| | - Nicola Pusterla
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California Davis, Tupper Hall 2108, One Shields Avenue, Davis, CA 95616, USA
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Young AE, Finno CJ. Current insights into equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy. Vet J 2024; 305:106129. [PMID: 38734404 DOI: 10.1016/j.tvjl.2024.106129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 05/06/2024] [Accepted: 05/07/2024] [Indexed: 05/13/2024]
Abstract
Equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy (eNAD/EDM) is an inherited neurodegenerative disease associated with vitamin E deficiency in the first year of life. It is the second most common cause of spinal ataxia in horses euthanized for neurologic disease. Equine NAD/EDM is characterized by neurologic signs including a symmetric proprioceptive ataxia (> grade 2/5) and a wide-base stance at rest. There are currently no antemortem tests for eNAD/EDM in any breed. Conclusive diagnosis requires postmortem histologic evaluation of the brainstem and spinal cord at necropsy. Research studies on antemortem biomarkers and genetic testing are ongoing. The development of a genetic test for eNAD/EDM would have widespread impact, even if it were breed specific. Currently, the best approach to eNAD/EDM is to focus on preventing cases by providing pregnant mares and foals with access to pasture. Alternatively, dams' diets can be supplemented with high doses of water-soluble RRR-α-tocopherol during the last trimester of gestation, with continued supplementation of foals through the first two years of life. It is important to measure horses' baseline serum vitamin E levels prior to supplementing. While considered generally safe, oversupplementation of vitamin E is possible and can lead to coagulopathies.
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Affiliation(s)
- Amy E Young
- Center for Equine Health, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Carrie J Finno
- Center for Equine Health, School of Veterinary Medicine, University of California, Davis, CA, USA; Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, CA, USA.
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Palmisano M, Kulp J, Bender S, Stefanovski D, Robinson M, Johnson A. Measurement of 8-hydroxy-2'-deoxyguanosine in serum and cerebrospinal fluid of horses with neuroaxonal degeneration and other causes of proprioceptive ataxia. J Vet Intern Med 2024; 38:1207-1213. [PMID: 38205913 PMCID: PMC10937501 DOI: 10.1111/jvim.16988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Accepted: 12/20/2023] [Indexed: 01/12/2024] Open
Abstract
BACKGROUND Eight-hydroxy-2'-deoxyguanosine (8-OHdG), a biomarker of oxidative damage evaluated in human neurodegenerative disease, has potential to correlate with postmortem diagnosis of neuroaxonal dystrophy/degenerative myeloencephalopathy (NAD/DM) in horses. HYPOTHESIS We hypothesized that 8-OHdG will be higher in CSF and serum from NAD/DM horses compared with horses with other neurologic diseases (CVSM, EPM) and a control group of neurologically normal horses. We also hypothesized that 8-OHdG will be higher in CSF compared with serum from NAD/DM horses. ANIMALS Fifty client-owned horses with postmortem diagnoses: 20 NAD/DM, 10 CVSM, 10 EPM, and 10 control horses. Serum and CSF samples were obtained between November 2010 and March 2022. METHODS Case-control study using biobanked samples was performed and commercial competitive ELISA kit (Highly Sensitive 8-OHdG Check ELISA) utilized. Concentration of 8-OHdG was quantitated in both CSF and serum and compared between groups. RESULTS No correlation was established between the measures of 8-OHdG in serum and CSF and group. CSF median [8-OHdG] for NAD/DM was 169.9 pg/mL (IQR25-75 : 67.18-210.6), CVSM 157.1 pg/mL (IQR25-75 : 132.1-229.1), EPM 131.4 pg/mL (IQR25-75 : 102.1-193.2), and control 149.8 pg/mL (IQR25-75 : 113.3-196.4). Serum median [8-OHdG] for NAD/DM was 130 pg/mL (IQR25-75 : 51.73-157.2), CVSM 125.8 pg/mL (IQR25-75 : 62.8-170.8), EPM 120.6 pg/mL (IQR25-75 : 87.23-229.7), and control 157.6 pg/mL (IQR25-75 : 97.15-245.6). Poisson regression analysis showed no difference established once confounding variables were considered. CONCLUSIONS Eight-OHdG did not aid in antemortem diagnosis of NAD/DM in this cohort of horses. At the time of diagnosis horses with NAD/DM do not have ongoing oxidative stress.
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Affiliation(s)
- Megan Palmisano
- Department of Clinical Studies, New Bolton CenterUniversity of Pennsylvania School of Veterinary MedicineKennett SquarePennsylvaniaUSA
| | - Jeaneen Kulp
- Department of Clinical Studies, New Bolton CenterUniversity of Pennsylvania School of Veterinary MedicineKennett SquarePennsylvaniaUSA
| | - Susan Bender
- Department of Pathobiology, New Bolton CenterUniversity of Pennsylvania School of Veterinary MedicineKennett SquarePennsylvaniaUSA
| | - Darko Stefanovski
- Department of Clinical Studies, New Bolton CenterUniversity of Pennsylvania School of Veterinary MedicineKennett SquarePennsylvaniaUSA
| | - Mary Robinson
- Department of Clinical Studies, New Bolton CenterUniversity of Pennsylvania School of Veterinary MedicineKennett SquarePennsylvaniaUSA
| | - Amy Johnson
- Department of Clinical Studies, New Bolton CenterUniversity of Pennsylvania School of Veterinary MedicineKennett SquarePennsylvaniaUSA
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Brown KA, Bender SJ, Johnson AL. Clinical and histopathological features in horses with neuroaxonal degeneration: 100 cases (2017-2021). J Vet Intern Med 2024; 38:431-439. [PMID: 38095342 PMCID: PMC10800219 DOI: 10.1111/jvim.16969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 12/01/2023] [Indexed: 01/23/2024] Open
Abstract
BACKGROUND Adult horses with proprioceptive ataxia and behavior changes that have histologic lesions consistent with neurodegenerative disease have been increasingly recognized. HYPOTHESIS/OBJECTIVES Describe the history, clinical findings and histopathologic features of horses presented to a referral institution with neuroaxonal degeneration. ANIMALS One hundred horses with a necropsy diagnosis of neuroaxonal degeneration compatible with neuroaxonal dystrophy/degenerative myeloencephalopathy (eNAD/EDM). METHODS Retrospective study of horses presented to the University of Pennsylvania, New Bolton Center, between 2017 and 2021 with a necropsy diagnosis of eNAD/EDM. RESULTS Affected horses had a median age of 8 years (range, 1-22), and the majority were Warmbloods (72). Sixty-eight horses had behavioral changes, and all 100 had proprioceptive ataxia (median grade, 2/5). Fifty-seven horses had abnormal findings on cervical vertebral radiographs, and 14 had myelographic findings consistent with compressive myelopathy. No antemortem diagnostic test results were consistently associated with necropsy diagnosis of neurodegenerative disease. All 100 horses had degenerative lesions characteristic of eNAD in the brainstem gray matter, and 24 had concurrent degenerative features of EDM in the spinal cord white matter. CONCLUSIONS AND CLINICAL IMPORTANCE Clinical and histopathologic findings in this large group of horses with neurodegenerative disease were most consistent with eNAD/EDM, but with a different signalment and clinical presentation from earlier descriptions. The increasing occurrence of neurodegenerative disease in horses and the safety risk posed emphasize the importance of focused research in affected horses.
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Affiliation(s)
- Kara A. Brown
- Department of Clinical Studies—New Bolton CenterUniversity of Pennsylvania School of Veterinary MedicineKennett SquarePennsylvaniaUSA
| | - Susan J. Bender
- Department of PathobiologyUniversity of Pennsylvania School of Veterinary MedicinePhiladelphiaPennsylvaniaUSA
| | - Amy L. Johnson
- Department of Clinical Studies—New Bolton CenterUniversity of Pennsylvania School of Veterinary MedicineKennett SquarePennsylvaniaUSA
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Ma Y, Peng S, Donnelly CG, Ghosh S, Miller AD, Woolard K, Finno CJ. Genetic polymorphisms in vitamin E transport genes as determinants for risk of equine neuroaxonal dystrophy. J Vet Intern Med 2024; 38:417-423. [PMID: 37937700 PMCID: PMC10800183 DOI: 10.1111/jvim.16924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 10/17/2023] [Indexed: 11/09/2023] Open
Abstract
BACKGROUND Equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy (eNAD/EDM) is an inherited neurodegenerative disorder associated with vitamin E deficiency. In humans, polymorphisms in genes involved in vitamin E uptake and distribution determines individual vitamin E requirements. HYPOTHESIS/OBJECTIVES Genetic polymorphisms in genes involved in vitamin E metabolism would be associated with an increased risk of eNAD/EDM in Quarter Horses (QHs). ANIMALS Whole-genome sequencing: eNAD/EDM affected (n = 9, postmortem [PM]-confirmed) and control (n = 32) QHs. VALIDATION eNAD/EDM affected (n = 39, 23-PM confirmed) and control (n = 68, 7-PM confirmed) QHs. Allele frequency (AF): Publicly available data from 504 horses across 47 breeds. METHODS Retrospective, case control study. Whole-genome sequencing was performed and genetic variants identified within 28 vitamin E candidate genes. These variants were subsequently genotyped in the validation cohort. RESULTS Thirty-nine confirmed variants in 15 vitamin E candidate genes were significantly associated with eNAD/EDM (P < .01). In the validation cohort, 2 intronic CD36 variants (chr4:726485 and chr4:731082) were significantly associated with eNAD/EDM in clinical (P = 2.78 × 10-4 and P = 4 × 10-4 , respectively) and PM-confirmed cases (P = 6.32 × 10-6 and 1.04 × 10-5 , respectively). Despite the significant association, variant AFs were low in the postmortem-confirmed eNAD/EDM cases (0.22-0.26). In publicly available equine genomes, AFs ranged from 0.06 to 0.1. CONCLUSIONS AND CLINICAL IMPORTANCE Many PM-confirmed cases of eNAD/EDM were wild-type for the 2 intronic CD36 SNPs, suggesting either a false positive association or genetic heterogeneity of eNAD/EDM within the QH breed.
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Affiliation(s)
- Yunzhuo Ma
- Department of Population Health and ReproductionSchool of Veterinary Medicine, University of California‐DavisDavis, California 95616USA
| | - Sichong Peng
- Department of Population Health and ReproductionSchool of Veterinary Medicine, University of California‐DavisDavis, California 95616USA
- Present address:
EclipsebioSan Diego, California 92121USA
| | - Callum G. Donnelly
- Department of Population Health and ReproductionSchool of Veterinary Medicine, University of California‐DavisDavis, California 95616USA
- Present address:
Cornell University College of Veterinary MedicineIthaca, New York 14853USA
| | - Sharmila Ghosh
- Department of Population Health and ReproductionSchool of Veterinary Medicine, University of California‐DavisDavis, California 95616USA
| | - Andrew D. Miller
- Department of Biomedical Sciences, Section of Anatomic PathologyCornell University College of Veterinary MedicineIthaca, New York 14853USA
| | - Kevin Woolard
- Department of Pathology and ImmunologySchool of Veterinary Medicine, University of California‐DavisDavis, California 95616USA
| | - Carrie J. Finno
- Department of Population Health and ReproductionSchool of Veterinary Medicine, University of California‐DavisDavis, California 95616USA
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Donnelly CG, Finno CJ. Vitamin E depletion is associated with subclinical axonal degeneration in juvenile horses. Equine Vet J 2023; 55:884-890. [PMID: 36516303 PMCID: PMC10264549 DOI: 10.1111/evj.13907] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 12/01/2022] [Indexed: 12/15/2022]
Abstract
BACKGROUND Phosphorylated neurofilament heavy, a marker of neuroaxonal damage, is increased in horses with equine neuroaxonal dystrophy. However, the temporal dynamics of this biomarker during the post-natal risk period are not understood. OBJECTIVE To measure serum and cerebrospinal fluid phosphorylated neurofilament heavy concentrations in juvenile foals across the post-natal window of susceptibility for equine neuroaxonal dystrophy. STUDY DESIGN Case-control in vivo experimental study. METHODS Concentrations of phosphorylated neurofilament heavy were measured using frozen serum and cerebrospinal fluid collected from 13 foals raised in a vitamin E deficient environment from 1 to 6 months of age. Four of these foals were produced by equine neuroaxonal dystrophy-affected dams, developed clinical signs consistent with equine neuroaxonal dystrophy and had a diagnosis confirmed by histopathology. The remaining nine foals, produced by healthy mares, were vitamin E depleted and remained clinically healthy. An additional cohort of foals, produced by healthy mares, were supplemented with vitamin E (α-tocopherol; α-TOH) from birth and sampled similarly. RESULTS Serum α-TOH concentrations were significantly higher in vitamin E supplemented healthy foals. Serum phosphorylated neurofilament heavy concentrations did not differ significantly between groups at any time point. Cerebrospinal fluid phosphorylated neurofilament heavy concentrations increased with age in healthy vitamin E depleted foals (p < 0.001); an effect that was not observed in healthy vitamin E supplemented foals. MAIN LIMITATIONS A genetically susceptible cohort supplemented with vitamin E was not available for comparison. CONCLUSION We demonstrate that vitamin E depletion may elevate cerebrospinal fluid phosphorylated neurofilament heavy in otherwise healthy juvenile foals by 6 months of age. We highlight an important cofactor to consider when interpreting cerebrospinal fluid phosphorylated neurofilament heavy concentrations in juvenile horses.
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Affiliation(s)
- Callum G. Donnelly
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, California, USA
| | - Carrie J. Finno
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, California, USA
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Donnelly CG, Johnson AL, Reed S, Finno CJ. Cerebrospinal fluid and serum proteomic profiles accurately distinguish neuroaxonal dystrophy from cervical vertebral compressive myelopathy in horses. J Vet Intern Med 2023; 37:689-696. [PMID: 36929645 DOI: 10.1111/jvim.16660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 02/03/2023] [Indexed: 03/18/2023] Open
Abstract
BACKGROUND Cervical vertebral compressive myelopathy (CVCM) and equine neuroaxonal dystrophy/degenerative myeloencephalopathy (eNAD/EDM) are leading causes of spinal ataxia in horses. The conditions can be difficult to differentiate, and there is currently no diagnostic modality that offers a definitive antemortem diagnosis. OBJECTIVE Evaluate novel proteomic techniques and machine learning algorithms to predict biomarkers that can aid in the antemortem diagnosis of noninfectious spinal ataxia in horses. ANIMALS Banked serum and cerebrospinal fluid (CSF) samples from necropsy-confirmed adult eNAD/EDM (n = 47) and CVCM (n = 25) horses and neurologically normal adult horses (n = 45). METHODS . A subset of serum and CSF samples from eNAD/EDM (n = 5) and normal (n = 5) horses was used to evaluate the proximity extension assay (PEA). All samples were assayed by PEA for 368 neurologically relevant proteins. Data were analyzed using machine learning algorithms to define potential diagnostic biomarkers. RESULTS Of the 368 proteins, 84 were detected in CSF and 146 in serum. Eighteen of 84 proteins in CSF and 30/146 in serum were differentially abundant among the 3 groups, after correction for multiple testing. Modeling indicated that a 2-protein test using CSF had the highest accuracy for discriminating among all 3 groups. Cerebrospinal fluid R-spondin 1 (RSPO1) and neurofilament-light (NEFL), in parallel, predicted normal horses with an accuracy of 87.18%, CVCM with 84.62%, and eNAD/EDM with 73.5%. MAIN LIMITATIONS Cross-species platform. Uneven sample size. CONCLUSIONS AND CLINICAL IMPORTANCE Proximity extension assay technology allows for rapid screening of equine biologic matrices for potential protein biomarkers. Machine learning analysis allows for unbiased selection of highly accurate biomarkers from high-dimensional data.
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Affiliation(s)
- Callum G Donnelly
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, Davis, California, USA
| | - Amy L Johnson
- Department of Clinical Studies, New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, Pennsylvania, USA
| | - Steve Reed
- Rood and Riddle Equine Hospital, Lexington, Kentucky, USA
| | - Carrie J Finno
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, Davis, California, USA
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Finno CJ, Johnson AL. Equine Neuroaxonal Dystrophy and Degenerative Myeloencephalopathy. Vet Clin North Am Equine Pract 2022; 38:213-224. [PMID: 35811203 DOI: 10.1016/j.cveq.2022.04.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Neuroaxonal degenerative disease in the horse is termed equine neuroaxonal dystrophy (eNAD), when pathologic lesions are localized to the brainstem and equine degenerative myeloencephalopathy (EDM) and degenerative changes extend throughout the spinal cord. Both pathologic conditions result in identical clinical disease, most commonly characterized by the insidious onset of ataxia during early development. However, later onset of clinical signs and additional clinical features, such as behavior changes, is also observed. A definitive diagnosis of eNAD/EDM requires histologic evaluation of the caudal medulla and cervicothoracic spinal cord. Strong evidence has suggested that eNAD/EDM is an inherited disorder and there seems to be a role for vitamin E acting as an environmental modifier to determine the overall severity of the phenotype of horses affected with eNAD/EDM.
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Affiliation(s)
- Carrie J Finno
- Department of Veterinary Population Health and Reproduction, School of Veterinary Medicine, University of California Davis, Room 4206 Vet Med 3A One Shields Avenue, Davis, CA 95616, USA.
| | - Amy L Johnson
- Department of Clinical Studies, University of Pennsylvania School of Veterinary Medicine- New Bolton Center, 382 West Street Road, Kennett Square, PA 19348, USA
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Rojas-Núñez I, Gomez AM, Palmer S, Mohammed HO. Serum Phosphorylated Neurofilament Heavy subunit levels and its association with the Risk for Catastrophic Injury in Thoroughbred Racehorses. J Equine Vet Sci 2022; 116:104057. [PMID: 35772595 DOI: 10.1016/j.jevs.2022.104057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 06/06/2022] [Accepted: 06/24/2022] [Indexed: 11/30/2022]
Abstract
Neurofilaments are structural proteins that are concentrated in the body and axons of neurons. Damage to the neurons or axons as a result of trauma or infectious diseases leads to the release of neurofilaments into blood and cerebrospinal fluid (CSF). This case-control study was carried out to compare serum levels of phosphorylated neurofilament heavy chain (pNF-H) between clinically healthy Thoroughbred (TB) horses and TB horses that suffered catastrophic musculoskeletal injuries (cMSI), and to investigate the correlation between putative risk factors and serum concentrations of pNF-H in injured horses. Blood samples were collected from clinically healthy horses and from horses that suffered cMSI. The concentration of pNF-H in serum samples was determined using the Phosphorylated Neurofilament H Sandwich enzyme-linked immunosorbent assay kit. A total of 343 horses were enrolled in the study (148 cases and 195 controls). The median serum concentration of pNF-H for controls was 0.0 ng/ml and for cases was 0.07 ng/ml. No significant difference was observed between the two groups in racing. The number of lifetime starts was correlated with serum pNF-H concentration in case horses. The serum concentration of pNF-H was higher in case horses that experienced cMSI while training than while racing. The number of lifetime starts is a proxy measure for several risk factors related to cumulative exercise load during the career of racehorses. Measurement of serum concentrations of pNF-H in TB racehorses does not support the hypothesis that subclinical neurologic injury or conditions are associated with catastrophic injury of TB racehorses.
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Affiliation(s)
- Irene Rojas-Núñez
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine Cornell University, Ithaca, NY
| | - Adriana Morales Gomez
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine Cornell University, Ithaca, NY
| | - Scott Palmer
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine Cornell University, Ithaca, NY
| | - Hussni O Mohammed
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine Cornell University, Ithaca, NY.
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Yuan A, Nixon RA. Neurofilament Proteins as Biomarkers to Monitor Neurological Diseases and the Efficacy of Therapies. Front Neurosci 2021; 15:689938. [PMID: 34646114 PMCID: PMC8503617 DOI: 10.3389/fnins.2021.689938] [Citation(s) in RCA: 100] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 09/02/2021] [Indexed: 01/01/2023] Open
Abstract
Biomarkers of neurodegeneration and neuronal injury have the potential to improve diagnostic accuracy, disease monitoring, prognosis, and measure treatment efficacy. Neurofilament proteins (NfPs) are well suited as biomarkers in these contexts because they are major neuron-specific components that maintain structural integrity and are sensitive to neurodegeneration and neuronal injury across a wide range of neurologic diseases. Low levels of NfPs are constantly released from neurons into the extracellular space and ultimately reach the cerebrospinal fluid (CSF) and blood under physiological conditions throughout normal brain development, maturation, and aging. NfP levels in CSF and blood rise above normal in response to neuronal injury and neurodegeneration independently of cause. NfPs in CSF measured by lumbar puncture are about 40-fold more concentrated than in blood in healthy individuals. New ultra-sensitive methods now allow minimally invasive measurement of these low levels of NfPs in serum or plasma to track disease onset and progression in neurological disorders or nervous system injury and assess responses to therapeutic interventions. Any of the five Nf subunits - neurofilament light chain (NfL), neurofilament medium chain (NfM), neurofilament heavy chain (NfH), alpha-internexin (INA) and peripherin (PRPH) may be altered in a given neuropathological condition. In familial and sporadic Alzheimer's disease (AD), plasma NfL levels may rise as early as 22 years before clinical onset in familial AD and 10 years before sporadic AD. The major determinants of elevated levels of NfPs and degradation fragments in CSF and blood are the magnitude of damaged or degenerating axons of fiber tracks, the affected axon caliber sizes and the rate of release of NfP and fragments at different stages of a given neurological disease or condition directly or indirectly affecting central nervous system (CNS) and/or peripheral nervous system (PNS). NfPs are rapidly emerging as transformative blood biomarkers in neurology providing novel insights into a wide range of neurological diseases and advancing clinical trials. Here we summarize the current understanding of intracellular NfP physiology, pathophysiology and extracellular kinetics of NfPs in biofluids and review the value and limitations of NfPs and degradation fragments as biomarkers of neurodegeneration and neuronal injury.
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Affiliation(s)
- Aidong Yuan
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY, United States
- Department of Psychiatry, NYU Neuroscience Institute, New York, NY, United States
| | - Ralph A. Nixon
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY, United States
- Department of Psychiatry, NYU Neuroscience Institute, New York, NY, United States
- Department of Cell Biology, New York University Grossman School of Medicine, (NYU), Neuroscience Institute, New York, NY, United States
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