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

Document Type

Article

Date of Original Version

1-1-2015

Abstract

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-1β monoclonal antibody and shown that this antibody has very high sensitivity and specificity for interleukin-1β protein. This antibody also neutralizes the effects of interleukin-1β protein in vitro. In the current study, we hypothesized that the neutralizing anti-interleukin-1β 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-1β antibody- (n. =. 7), and sham-control antibody- (n. =. 2) treated animals. Systemic infusions of placebo (0.154. M NaCl) or anti-interleukin-1β 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-1β protein and anti-interleukin-1β 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 (. Ki) with α-aminoisobutyric acid in multiple brain regions. Interleukin-1β protein was also measured in parietal cerebral cortices and tight junction proteins in multiple brain regions by Western immunoblot. Cerebral cortical interleukin-1β protein increased (. P<. 0.001) after ischemia-reperfusion. After anti-interleukin-1β monoclonal antibody infusions, plasma anti-interleukin-1β monoclonal antibody was elevated (. P<. 0.001), brain anti-interleukin-1β monoclonal antibody levels were higher (. P<. 0.03), and interleukin-1β 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-reperfusion-related increases in Ki across the brain regions (. P<. 0.04), and Ki showed an inverse linear correlation (r. = -. 0.65, P<. 0.02) with anti-interleukin-1β monoclonal antibody concentrations in the parietal cortex, but had little effect on tight junction protein expression. We conclude that systemic anti-interleukin-1β monoclonal antibody infusions after ischemia result in brain anti-interleukin-1β antibody uptake, and attenuate ischemia-reperfusion-related interleukin-1β protein up-regulation and increases in blood-brain barrier permeability across brain regions in the fetus. The pro-inflammatory cytokine, interleukin-1β, contributes to impaired blood-brain barrier function after ischemia in the fetus.

Publication Title, e.g., Journal

Neurobiology of Disease

Volume

73

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