Elevated Adenosine Kinase and Decreased ENTPD1 mRNA Levels in Peripheral Blood Leukocytes of Patients with MASLD Differentiate Metabolic Dysfunction-Associated Steatohepatitis from Hepatic Steatosis

Abstract

Background: Adenosine kinase (ADK) and the ectonucleotidases CD39 and CD73 regulate adenosine metabolism and play important roles in the pathogenesis of liver diseases. Their involvement in metabolic dysfunction-associated steatotic liver disease (MASLD) remains insufficiently characterized, particularly in humans. This study aimed to comparatively analyze ADK levels, the mRNA levels of the long and short ADK isoforms and the ENTPD1, NT5E, and ADORA2A genes in peripheral blood leukocytes (PBLs), and the proportion of CD39- and CD73-expressing cells in the blood of healthy individuals and patients with different forms of MASLD (hepatic steatosis (HS) and metabolic dysfunction-associated steatohepatitis (MASH)). Methods: Blood samples were obtained from 42 healthy individuals and 98 patients with MASLD. ADK and cytokine levels were measured by ELISA. mRNA levels were determined by RT-PCR. The proportions of CD39- and CD73-expressing cells were determined by flow cytometry. Results: Patients with HS and MASH differed in ADK concentration and relative ENTPD1 gene expression in PBL. Compared with HS, MASH was characterized by higher ADK concentrations and lower ENTPD1 mRNA levels, both of which showed potential for distinguishing MASH from HS: ADK, AUC = 0.764 (95% CI, 0.637–0.892; p = 0.001); ENTPD1 mRNA, AUC = 0.649 (95% CI, 0.546–0.752; p = 0.007). Patients with MASLD, including those with HS and MASH, had lower proportions of CD39+ monocytes than controls, whereas the proportions of CD4+CD39+ T helper cells did not differ significantly between the groups. Conclusions: ADK levels in PBLs may be associated with the presence and activity of inflammation in MASLD. Compared with patients with HS and healthy controls, patients with MASH had elevated ADK levels and lower relative levels of ENTPD1 transcripts in PBLs. The latter finding may be related to the reduced proportion of CD39+ monocytes.