Spotlight on liver macrophages for halting injury and progression in nonalcoholic fatty liver disease

Introduction Nonalcoholic fatty liver disease (NAFLD) is considered the hepatic manifestation of the metabolic syndrome and is rapidly emerging as the leading cause of liver-related morbidity and mortality. Macrophages play an essential role in the development and progression of NAFLD. Areas covered In this review, we provide an update on recent studies of drugs, which directly or indirectly affect macrophages in NAFLD, and discuss the implication of macrophage biomarkers to monitor the disease stage and progression/regression. Expert opinion There is an unmet need for a better understanding of disease pathogenesis from hepatic fat accumulation to disease progression with inflammation and fibrosis. We expect that future research will uncover additional objects/pathways as treatment targets. We speculate that this will involve better characterization of the gut microbiome, damage-associated molecular patterns (DAMPS) or molecules and pathways involved in the development of DAMPS, and advanced molecular biology studies including single-cell sequencing of macrophage subpopulations. In addition, we speculate that studies focusing on pharmaceuticals that improve insulin resistance, diminish the metabolic syndrome, and reduce fibrosis will prevail.