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

Neurobiol Dis. 2015 Jan;73:118-29. doi: 10.1016/j.nbd.2014.09.007. Epub 2014 Sep 26.

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 24h 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 (0.154M 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 4h 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.

Keywords: Blood–brain barrier; Brain; Cytokines; Interleukin-1β; Ischemia–reperfusion; Monoclonal antibody; Ovine fetus; Sheep.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Neutralizing / pharmacology
  • Antibodies, Neutralizing / therapeutic use*
  • Blood Pressure / drug effects
  • Blood-Brain Barrier / drug effects*
  • Blood-Brain Barrier / physiopathology
  • Brain / embryology
  • Brain / metabolism
  • Capillary Permeability / drug effects
  • Carotid Stenosis / complications
  • Cytokines / metabolism
  • Disease Models, Animal
  • Embryo, Mammalian
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Fetal Hypoxia / drug therapy*
  • Fetal Hypoxia / etiology
  • Fetal Hypoxia / pathology*
  • Heart Rate, Fetal / drug effects
  • Interleukin-1beta / immunology*
  • Interleukin-1beta / metabolism
  • Mice
  • Pregnancy
  • Regional Blood Flow / drug effects
  • Sheep
  • Tight Junction Proteins / metabolism

Substances

  • Antibodies, Neutralizing
  • Cytokines
  • Interleukin-1beta
  • Tight Junction Proteins