Serum Glial Fibrillary Acidic Protein as a Diagnostic Biomarker in Dogs with Progressive Myelomalacia

Abstract

ABSTRACT. In humans, increased levels of GFAP in the CSF and blood have been reported with various neural diseases. However, there has been no study describing the usefulness of GFAP in the blood for disease of the spinal cord in dogs. The aim of this study was to describe the utility of GFAP in serum for a diagnosis of progressive myelomalacia. Fifty-six dogs with acute thoracolumbar IVDD diagnosed by computed tomography with myelography or MRI were included. Serum specimens were collected at initial presentation from all cases and at follow-up examinations from some cases. Serum samples were assayed for GFAP concentrations using a commercially available GFAP ELISA Kit. Progressive myelomalacia was the final diagnosis in 8/51 cases (15.6%). Eight dogs had clinical signs suggestive of progressive myelomalacia, of which 6 were positive and 2 were negative by GFAP. Seven dogs had a detectable level of serum GFAP, of which 6 had the onset of progressive myelomalacia. The sensitivity and specificity of the GFAP to progressive myelomalacia were 75% and 97.7%, respectively. The results suggest the utility of GFAP in serum in the diagnosis of progressive myelomalacia.

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

“…For biomarkers with a significant relationship with outcome, a receiver operator characteristic (ROC) curve analysis was performed and the sensitivity and specificity of serum biomarker concentrations for prediction of ambulatory status at 6 months was calculated. This allowed comparison with previously published data on these biomarkers in canine SCI . The accuracy of prediction of recovery using cutoffs established in the ROC curve analysis was calculated from the sum of true positive and true negative results divided by the total number of tests performed.…”

“…These include neuronal and glial (astrocyte and oligodendroglia) specific proteins for which canine‐compatible ELISA tests are now available . Indeed, the presence of glial fibrillary acidic protein (GFAP) in serum might detect progressive myelomalacia (PMM) . However, the ability to predict outcome in less extreme scenarios than PMM has proven more challenging, with sensitivity being sacrificed for specificity, perhaps in part because of dogs presenting at different times after injury, different release rates, and different half‐lives of biomarkers …”

Clinical Characteristics of Dogs with Progressive Myelomalacia Following Acute Intervertebral Disc Extrusion

“…The similarity of results in the whole case cohort and the subset with necropsy confirmation suggests our diagnostic criteria were adequate. An antemortem bedside diagnostic test for PMM has not yet been developed, although measurement of serum levels of glial fibrillary acid protein (GFAP), a major constituent protein of mature astrocytes, using an ELISA test is highly specific (97.7%), with lower sensitivity (75%) . This test is unfortunately not available as a rapid turnaround test.…”

“…9 While there are several published studies on the histopathologic lesions, risk factors for its development, diagnostic, and imaging characteristics of PMM, to date, there is no large-scale retrospective study describing its clinical characteristics. 4,[10][11][12][13][14][15] The goal of this study was to describe the clinical signs associated with PMM, including their time of onset and their rate of progression in a large case cohort.…”

Increase in oxidative stress biomarkers in dogs with ascending–descending myelomalacia following spinal cord injury

“…An increase in glial fibrillary acidic protein, a marker of astrocyte proliferation and secondary injury has been shown to be elevated in the cerebrospinal fluid of dogs with A-D myelomalacia [24].…”