CTSB and metabolic dysfunction-associated steatohepatitis: While most of the studies mentioned above regarding cathepsins and metabolism are descriptive, mechanistic studies have demonstrated that the amelioration of NASH-related symptoms upon CTSB inhibition might be linked to the restoration of the levels of the master metabolic regulator sirtuin-1 (SIRT1) [62,63,64], which plays an essential (beneficial) role in the metabolic regulation of lipids, glucose, and insulin [65].