Navigating the complex role of senescence in liver disease

Cellular senescence, an irreversible state of cell cycle arrest characterized by phenotypic changes and a specific secretory profile, plays a dual role in liver health and disease. Under physiological conditions, senescence aids organ repair and regeneration, but its accumulation due to aging or pathological stress significantly contributes to chronic liver diseases, including alcoholic liver disease, metabolic dysfunction-associated steatohepatitis, liver fibrosis, and hepatocellular carcinoma. Senescence is identified by a range of cellular and molecular changes, such as morphological alterations, expression of cell cycle inhibitors, senescence-associated β-galactosidase activity, and nuclear membrane changes. The onset of senescence in organ cells can affect the entire organism, primarily through the senescence-associated secretory phenotype, which has autocrine, paracrine, and endocrine effects on tissue microenvironments. The objective of this review is to offer a contemporary overview of the pathophysiological events involving hepatic senescent cells and to elucidate their role in the onset and progression of liver diseases, particularly through mechanisms like telomere shortening, genomic and mitochondrial DNA damage, and inflammation. Additionally, this review discusses the emerging senolytic therapies aimed at targeting senescent cells to delay or mitigate liver disease progression. The therapeutic potential of these interventions, alongside their safety and effectiveness, highlights the need for further research to refine these approaches and address unresolved problems in the field of hepatic cellular senescence.