Central Administration of Recombinant IGF1 Is Neuroprotective in a Rodent Model of Acute Liver Failure.

Abstract

Acute liver failure is often accompanied by neurological disturbances collectively referred to as hepatic encephalopathy (HE), characterized by neuroinflammation and subsequent cognitive decline. Insulin-like growth factor 1 (IGF1) is a neuroprotective peptide with anti-inflammatory properties in the brain. The role of IGF1 in cognitive deficits and neuroinflammation during HE remains largely unexplored. In C57Bl/6 mice, HE was established through an intraperitoneal injection of azoxymethane (AOM), and tissues were collected at defined time points during disease development. IGF1 expression in the cortex was downregulated following AOM administration. Central infusion of recombinant mouse IGF1 (rmIGF1) before AOM injection resulted in delayed neurological impairment, reduced microglial activation, and decreased proinflammatory cytokine and chemokine production in AOM mice. In vitro, rmIGF1 and conditioned media derived from rmIGF1-treated primary neurons attenuated phagocytic activity and C-C motif chemokine ligand 2 (CCL2) production in the microglial cell line EOC-20. Collectively, our results show that IGF1, whose levels decline during HE, alleviates neuroinflammation and improves the pathological state of AOM-treated mice through the suppression of microglial activation and the regulation of neuron-microglia paracrine communication.