Ketogenic diet induces an inflammatory reactive astrocytes phenotype reducing glioma growth

The use of a ketogenic diet (KD) in glioma is currently tested as an adjuvant treatment in standard chemotherapy regimens. The metabolic shift induced by the KD leads to the generation of ketone bodies that can influence glioma cells and the surrounding microenvironment, but the mechanisms have not yet been fully elucidated. Here, we investigated the potential involvement of glial cells as mediators of the KD-induced effects on tumor growth and survival rate in glioma-bearing mice. Specifically, we describe that exposing glioma-bearing mice to a KD or to β-hydroxybutyrate (β-HB), one of the main KD metabolic products, reduced glioma growth in vivo, induced a pro-inflammatory phenotype in astrocytes and increased functional glutamate transporters. Moreover, we described increased intracellular basal Ca2+ levels in GL261 glioma cells treated with β-HB or co-cultured with astrocytes. These data suggest that pro-inflammatory astrocytes triggered by β-HB can be beneficial in counteracting glioma proliferation and neuronal excitotoxicity, thus protecting brain parenchyma.