Neutralizing anti-interleuldn-1β antibodies modulate fetal blood-brain barrier function after ischemia

We have previously shown that increases in blood-brain barrier permeability represent an important component of ischemia-reperfusion related brain injury in the fetus. Pro-inflammatory cytokines could contribute to these abnormalities in blood-brain barrier function. We have generated pharmacological quantities of mouse anti-ovine interleukin-1 beta monoclonal antibody and shown that this antibody has very high sensitivity and specificity for interleukin-1 beta protein. This antibody also neutralizes the effects of interleukin-1 beta protein in vitro. In the current study, we hypothesized that the neutralizing anti-interleukin-1 beta monoclonal antibody attenuates ischemia-reperfusion related fetal blood-brain barrier dysfunction. Instrumented ovine fetuses at 127 days of gestation were studied after 30 min of carotid occlusion and 24 h of reperfusion. Groups were sham operated placebo-control-(n = 5), ischemia-placebo-(n = 6), ischemia-anti-IL-1 beta antibody-(n = 7), and sham-control antibody-(n = 2) treated animals. Systemic infusions of placebo (0.154 M NaCI) or antiinterleukin-1 beta monoclonal antibody (5.1 +/- 0.6 mg/kg) were given intravenously to the same sham or ischemic group of fetuses at 15 min and 4 h after ischemia. Concentrations of interleukin-1 beta protein and anti-interleukin1 beta monoclonal antibody were measured by ELISA in fetal plasma, cerebrospinal fluid, and parietal cerebral cortex. Blood-brain barrier permeability was quantified using the blood-to-brain transfer constant (K-i) with ct-aminoisobutyric acid in multiple brain regions. Interleukin-1 beta protein was also measured in parietal cerebral cortices and tight junction proteins in multiple brain regions by Western immunoblot Cerebral cortical interleukin-1 beta protein increased (P < 0.001) after ischemia-reperfusion. After anti-interleukin-1 beta monoclonal antibody infusions, plasma anti-interleukin-1 beta monoclonal antibody was elevated (P <0.001), brain antiinterleukin-1 beta monoclonal antibody levels were higher (P< 0.03), and interleukin-1 beta protein concentrations (P < 0.03) and protein expressions (P < 0.001) were lower in the monoclonal antibody-treated group than in placebo-treated-ischemia-reperfusion group. Monoclonal antibody infusions attenuated ischemia-reperfusionrelated increases in Ki across the brain regions (P < 0.04), and K-i showed an inverse linear correlation (r = 0.65, P< 0.02) with anti-interleukin-1 beta monoclonal antibody concentrations in the parietal cortex, but had little effect on tight junction protein expression. We conclude that systemic anti-interleuldn-1 beta monoclonal antibody infusions after ischemia result in brain anti-interleukin-1 beta antibody uptake, and attenuate ischemia-reperfusion-related interleukin-1 beta protein up-regulation and increases in blood-brain barrier permeability across brain regions in the fetus. The pro-inflammatory cytokine, interleuldn-1 beta, contributes to impaired bloodbrain barrier function after ischemia in the fetus. (C) 2015 Elsevier Inc All rights reserved.