TNF and Huntington disease: Therefore cholesterol homeostasis is important for microglia phagocytosis functions, and in vitro treatment of microglia with simvastatin, a cholesterol lowering drug, alters microglia phagocytosis, BDNF and inflammatory factors (IL1-β, TNFα) release (Churchward and Todd, 2014), described to be downregulated in HD (Björkqvist et al., 2008).