Caffeine Citrate does not reduce brain injury following inflammation-amplified hypoxia ischaemia or hypoxia ischaemia in the Newborn Piglet Model.

Abstract

There is a need to develop alternative therapies for neonatal encephalopathy (NE) in term babies. Caffeine citrate exposure saw benefit in preclinical models of hypoxia-ischaemia (HI). We assessed the safety and cytoprotective efficacy of caffeine citrate in an inflammation-amplified (IA-HI) and HI newborn piglet model based on the probability of treatment superiority (Pr_(sup)) of magnetic resonance spectroscopy, amplitude integrated encephalography (aEEG/EEG) and immunohistochemistry outcomes. Eighteen newborn piglets were randomised to saline, 20/10/10 mg/kg or 60/30/30 mg/kg caffeine citrate following IA-HI. A further twenty piglets were randomised to saline or 40/10/10 mg/kg caffeine citrate following HI. Caffeine plasma concentrations were within range following a 20/10/10 mg/kg dosage but were lower than putative target levels following a 40/10/10 mg/kg dosage. Caffeine concentrations exceeded toxic levels following a 60/30/30 mg/kg dosage. Following IA-HI, 20/10/10 or 60/30/30 mg/kg caffeine citrate treatment failed to reduce white matter (WM) (Pr_(sup) 39.3 %, 52.5 %) and basal ganglia and thalamic (BGT) (Pr_(sup) 35.0 %, 50.3 %) lactate/N-acetylaspartate (Lac/NAA), preserve the phosphocreatine/exchange phosphate pool (PCr/Epp) ratio (Pr_(sup) 44.2 %, 62.0 %), or improve aEEG/EEG recovery (Pr_(sup) 22.4 %, 21.7 %). A 60/30/30 mg/kg dose demonstrated increased cell death, indicating toxicity. Following HI, 40/10/10 mg/kg caffeine citrate treatment failed to reduce WM (Pr_(sup) 58.3 %) and BGT (Pr_(sup) 48.0 %) Lac/NAA, preserve the PCr/Epp ratio (Pr_(sup) 72.8 %), or improve aEEG/EEG recovery (Pr_(sup) 48.0 %), with seizures more refractory. However, there was a modest benefit in male caffeine-treated piglets following HI. The lack of neuroprotection observed following caffeine citrate treatment after both IA-HI and HI suggests further preclinical studies are required before clinical translation for term babies with NE.