Sakura Nakada

Background: Hypoxic-ischemic (HI) brain injury is a leading cause of long-term neurodevelopmental morbidities in neonates. Human plasma-derived Inter-Alpha Inhibitor Proteins (hIAIPs) are neuroprotective after HI brain injury in neonatal rats. The light chain (bikunin) of hIAIPs inhibits proteases involved in the coagulation of blood. Newborns exposed to HI can be at risk for significant bleeding in the brain and other organs. Objective: The objectives of the present study were to assess the pharmacokinetics (PK) and the duration of bleeding after intraperitoneal (IP) administration of hIAIPs in HI-exposed male and female neonatal rats. Methods: HI was induced with the Rice-Vannucci method in postnatal (P) day-7 rats. After the right common carotid artery ligation, rats were exposed to 90 min of 8% oxygen. hIAIPs (30 mg/kg, IP) were given immediately after Sham or HI exposure in the PK study and serum was collected 1, 6, 12, 24, or 36 h after the injections. Serum hIAIP concentrations were measured with a competitive ELISA. ADAPT5 software was used to fit the pooled PK data considering first-order absorption and disposition. hIAIPs (60 mg/kg, IP) were given in the bleeding time studies at 0, 24 and 48 h after HI with tail bleeding times measured 72 h after HI. Results: IP administration yielded significant systemic exposure to hIAIPs with PK being affected markedly including primarily faster absorption and reduced elimination as a result of HI and modestly of sex-related differences. hIAIP administration did not affect bleeding times after HI. Conclusion: These results will help to inform hIAIP dosing regimen schedules in studies of neuroprotection in neonates exposed to HI.

Neuroinflammation contributes to hypoxic-ischemic (HI) brain injury. Inter-alpha inhibitor proteins (IAIPs) have important immunomodulatory properties. Human (h) plasma-derived IAIPs reduce brain injury and improve neurobehavioral outcomes after HI. However, the effects of hIAIPs on neuroinflammatory biomarkers after HI have not been examined. We determined whether hIAIPs attenuated HI-related neuroinflammation. Postnatal day-7 rats exposed to sham-placebo, or right carotid ligation and 8% oxygen for 90 minutes with placebo, and hIAIP treatment were studied. hIAIPs (30 mg/kg) or PL was injected intraperitoneally immediately, 24, and 48 hours after HI. Rat complete blood counts and sex were determined. Brain tissue and peripheral blood were prepared for analysis 72 hours after HI. The effects of hIAIPs on HI-induced neuroinflammation were quantified by image analysis of positively stained astrocytic (glial fibrillary acid protein [GFAP]), microglial (ionized calcium binding adaptor molecule-1 [Iba-1]), neutrophilic (myeloperoxidase [MPO]), matrix metalloproteinase-9 (MMP9), and MMP9-MPO cellular markers in brain regions. hIAIPs reduced quantities of cortical GFAP, hippocampal Iba-1-positive microglia, corpus callosum MPO, and cortical MMP9-MPO cells and the percent of neutrophils in peripheral blood after HI in male, but not female rats. hIAIPs modulate neuroinflammatory biomarkers in the neonatal brain after HI and may exhibit sex-related differential effects.