Biomarkers for neural injury and infection in small animals

Serum phosphorylated neurofilament heavy chain as a diagnostic biomarker for progressive myelomalacia in dogs with thoracolumbar intervertebral disc herniation

Background

Serum phosphorylated neurofilament‐heavy chain (pNF‐H) has not been longitudinally evaluated in dogs that develop progressive myelomalacia (PMM) after Type I intervertebral disc herniation (IVDH).

Objectives

To determine if serum pNF‐H concentrations would predict outcome of neuroligical disease in dogs with acute, severe thoracolumbar myelopathy secondary to Type I IVDH.

Animals

Thirty‐nine client‐owned dogs with thoracolumbar myelopathy secondary to IVDH.

Methods

Prospective controlled cohort study. Serum was collected from dogs undergoing hemilaminectomy at multiple timepoints. Final neurological status was established at 12 months and groups were stratified accordingly. Comparisons between outcome and pNF‐H concentration at each timepoint was examined using Kruskal‐Wallis analysis of variance on ranks and receiver operator characteristics curve analysis.

Results

Median serum pNF‐H concentrations were not significantly different between deep pain negative dogs that did or did not recover at any timepoint (baseline: 0.37 ng/mL [0‐0.9 ng/mL] vs 0 ng/mL [0‐0.9 ng/mL], P > 1; 24 hours: 1.25 ng/mL [0.35‐7.23 ng/mL] vs 1.53 ng/mL [0‐11.94 ng/mL], P > 1; 48 hours: 1.22 ng/mL [0.63‐6.62 ng/mL] vs 2.12 ng/mL [0‐20.72 ng/mL], P >  1; 72 hours: 2.77 ng/mL [1.33‐6.62 ng/mL] vs 16.69 ng/mL [4.02‐40.12 ng/mL], P >  1). Dogs that developed PMM had significantly higher serum pNF‐H concentrations after surgery compared to all other cohorts at 24 hours: 39.88 ng/mL (25.74‐50.68 ng/mL); P < .05 and 72 hours: 223.9 ng/mL (155.4‐263.7 ng/mL); P < .05. A serum pNF‐H concentration ≥31.39 ng/mL was 83.33% sensitive and 100% specific for identifying PMM in this cohort.

Conclusions and Clinical Importance

Serum pNF‐H is a promising biomarker for antemortem diagnosis of PMM in dogs with acute, severe thoracolumbar myelopathy secondary to Type I IVDH.

Time course and prognostic value of serum GFAP, pNFH, and S100β concentrations in dogs with complete spinal cord injury because of intervertebral disc extrusion

BACKGROUND

A noninvasive biomarker is needed to predict recovery from severe spinal cord injury (SCI) because of thoracolumbar intervertebral disc extrusion (TL-IVDE). Proteins released from neural and glial cells can be detected in the blood and show promise as prognostic tools, but their concentration is influenced by time after injury.

HYPOTHESIS/OBJECTIVES

Serum concentrations of glial fibrillary acidic protein (GFAP), phosphorylated neurofilament heavy chain (pNFH), and S100β will follow different time courses; measurement of combinations of these proteins will predict outcome.

ANIMALS

Thirty-one dogs with TL-IVDE causing paralysis with no pain perception.

METHODS

Prospective study. Serum samples were taken at presentation and intervals over 56 days and banked at -80°C. Glial fibrillary acidic protein, pNFH, and S100β concentrations were measured using ELISA tests and plotted against time from onset of nonambulatory status. Outcome was established at 6 months. The association between biomarker concentration and outcome was examined using logistic regression, receiver operator characteristics curve analysis, and model development.

RESULTS

Thirty-one dogs participated, 3/31 (10%) developed progressive myelomalacia and 19/31 (62%) recovered ambulation. Glial fibrillary acidic protein and S100β concentrations rose for the first 1 to 3 days, and were undetectable by 14 and 28 days, respectively. Phosphorylated neurofilament heavy chain concentrations peaked at 14 days and were detectable at 56 days. Glial fibrillary acidic protein concentrations in the first 72 hours after onset of nonambulatory status predicted recovery with an accuracy of 76.7%-89% depending on sample timing.

CONCLUSIONS AND CLINICAL IMPORTANCE

Serum GFAP concentrations can be used to predict outcome in clinically complete SCI. A rapid inexpensive bedside test is needed.

Neuron-specific enolase as biomarker for possible neuronal damage in dogs with distemper vírus

ABSTRACT: Neuron-specific enolase (NSE) is a biomarker of neuronal cell lysis, which demonstrates stability in extracellular fluids such as blood and cerebrospinal fluid. To the authors knowledge there is no research information comparing the use of NSE in dogs with and without encephalitis, putting in evidence the importance of that biomarker to detect neuronal damage in dogs. The objective was to compare the serum NSE levels in dogs with and without encephalitis, and to determine the serum NSE levels in normal dogs. Thirty eight dogs were evaluated, 19 dogs with encephalitis (EG Group) and 19 dogs without encephalitis (CG Group). The criteria for inclusion in the EG Group were presence of neurological signs in more than one part of the CNS (multifocal syndrome) and positive molecular diagnosis for canine distemper virus; for the CG Group were an age between 1 to 7 years and be clinically normal; NSE were measured in serum using an ELISA assay, and the results were compared. In the EG Group the NSE values were higher with significant difference (P=0.0053) when compared with the CG Group. NSE is a biomarker that can be measured in serum samples of dogs to monitor neuronal lesions in encephalitis.

Biomarkers in Veterinary Medicine

This article summarizes the relevant definitions related to biomarkers; reviews the general processes related to biomarker discovery and ultimate acceptance and use; and finally summarizes and reviews, to the extent possible, examples of the types of biomarkers used in animal species within veterinary clinical practice and human and veterinary drug development. We highlight opportunities for collaboration and coordination of research within the veterinary community and leveraging of resources from human medicine to support biomarker discovery and validation efforts for veterinary medicine.

Recovery of stepping and coordination in dogs following acute thoracolumbar intervertebral disc herniations

Prospective data on the recovery of coordination in dogs suffering acute thoracolumbar intervertebral disc herniations (TL-IVDH) are limited. The purpose of this study was to use treadmill based and open field scores (OFS) to quantify recovery of stepping ability and forelimb, hindlimb coordination in the 6 weeks following surgical decompression of dogs with TL-IVDH. Sixty-three dogs were grouped at presentation as grades 3 (non-ambulatory paraparetic), 4 (paraplegic) or 5 (paraplegic without pain sensation) and were evaluated 2, 4, and 6 weeks post-operatively. Stepping scores and Regularity Index (RI), a measure of coordination, were calculated from treadmill walking, and an OFS incorporating supported and unsupported walking was assigned. Outcomes for the three measures were compared between groups and correlation between scoring methods was assessed. Grade 3 and 4 dogs recovered ambulation by 2 weeks, reaching median stepping scores of 96 and 90% by 6 weeks, respectively. Recovery of coordination differed between groups 3 and 4 with median RI scores of 93.9% and 63%, respectively, by 6 weeks. Eight grade 5 dogs failed to recover independent ambulation by 6 weeks. Nine dogs recovered with scores that were significantly worse than the grade 3 and 4 dogs at 6 weeks for stepping score (P < 0.001) and RI (P < 0.001). OFS correlated closely with stepping and RI scores and each group was significantly different using this ordinal scale. In conclusion, recovery of coordination was incomplete in dogs that showed good recovery of stepping. The data generated could be used for clinical trial design.