Exploring the Role of Thy-1 and Its Soluble Form Regarding Fibrosis Severity in Primary Biliary Cholangitis and Metabolic Dysfunction-Associated Fatty Liver Disease.

Background and Aim: Portal myofibroblasts (PMF) are known to be critical in bile duct injury, but their role in liver fibrogenesis remains underexplored. Thy-1, an adhesion molecule detected as soluble Thy-1 (sThy-1) in serum, is primarily expressed by portal myofibroblasts (PMF) and, to a lesser extent, hepatic stellate cells (HSC), serving as a marker for myofibroblast activity in liver pathology. This study aimed to elucidate the correlation between Thy-1 expression in liver histology and sThy-1 levels in serum with the degree of liver fibrosis in patients with primary biliary cholangitis (PBC) and metabolic dysfunction-associated steatotic liver disease (MASLD). Methods: Liver histology samples were stained for Thy-1, and sThy-1 was measured using an enzyme-linked immunosorbent assay (ELISA). Results: In patients with PBC and MASLD, an association between portal Thy-1 expression and the extent of fibrosis was observed. Notably, while sinusoidal Thy-1 expression aligned with fibrosis severity in PBC ( Conclusions: Thy-1 expression levels were associated with the severity of fibrosis, which could support its role in monitoring the presence and activity of myofibroblasts in liver diseases.