MPO and metabolic dysfunction-associated steatohepatitis: To further examine the role of MPO in NASH, we took advantage of the fact that MPO is exclusively expressed in the hematopoietic system [22], and performed bone marrow transplantation experiments that resulted in the generation of combined MPO-deficient, LDL-R-deficient mice (LDLR−/−/MPO−/−tp) mice.