• Horse;
  • Phosphorylated axonal forms of neurofilament H;
  • Ubiquitin C-terminal hydrolase

Background: Neonatal hypoxic-ischemic encephalopathy (NHIE) is a disease affecting newborn foals for which there is no antemortem diagnostic test.

Hypothesis: Ubiquitin C-terminal hydrolase 1 (UCHL1) and the phosphorylated axonal forms of neurofilament H (pNF-H) are markers of brain injury in foals with NHIE.

Animals: Thirty-three foals with a clinical diagnosis consistent with NHIE and 17 healthy foals.

Methods: Retrospective study. Concentrations of UCHL1 and pNF-H in plasma were measured by ELISA. The performance of the assays for the diagnosis of NHIE was assessed by receiver operating characteristic curve analysis. Concentrations of UCHL1 and pNF-H were measured throughout the brains of 2 healthy foals.

Results: The diagnostic performance of UCHL1 (AUC = 0.86) was significantly higher (P= .001) than that of pNF-H (0.52) for the diagnosis of NHIE. Median concentrations of UCHL1 (6.57 ng/mL; 2.35–11.90 ng/mL) in foals with a clinical diagnosis of NHIE were significantly (P < .001) higher than those of healthy controls (2.52 ng/mL; 1.4–4.01 ng/mL). The right sided reference interval for UCHL1 concentrations in healthy foals was 0–4.01 ng/mL. The sensitivity and specificity of UCHL1 (>4.01 ng/mL) for diagnosis of NHIE were 70% (51–84%) and 94% (72–99%), respectively. UCHL1 concentrations were higher in gray than white matter, while pNF-H concentrations were higher in white than gray matter.

Conclusions and Clinical Importance: UCHL1 has potential as a marker of brain injury in foals with NHIE.