1). The amount of claudin-1 was higher in liver samples from patients with severe hepatitis C recurrence (particularly 12 months after LT) compared to those with mild recurrence, but the differences did not reach statistical significance (Supporting Table 1). Interestingly, in the subgroup of patients with severe cholestatic hepatitis

(n = 12) the amount of claudin-1 12 months after LT was significantly higher compared to the remaining patients (P = 0.005) (Fig. 5). Claudin-1 levels did not correlate with any of the PD-0332991 datasheet biochemical markers of cholestasis (gamma glutamyl transpeptidase, alkaline phosphatase, bilirubin) or HCV-RNA concentration obtained at the same timepoints. With regard to mRNA quantification, we found no correlation between mRNA and protein abundance levels (as quantified by confocal microscopy) either for claudin-1 (r = 0.2, not significant [ns]) or for occludin (r = 0.1, ns). Indeed, claudin-1 mRNA levels remained stable over time in HCV-infected patients; occludin mRNA

levels increased, although the difference did not reach statistical significance (Supporting Fig. 1). Similarly, we did not detect significant differences in the mRNA levels of these two proteins in individuals with mild or severe disease recurrence. HCV entry is a complex process involving several receptors. It is believed that HCV particles are consecutively bound by a complex formed by SR-B1 and CD81. Virus associated with CD81 would AZD5363 in vitro then be transferred into tight junctions, where HCV would interact with claudin-1 Glutathione peroxidase and occludin to enter the cell by clathrin-dependent endocytosis.4-10 Another hypothesis suggests that

internalization of HCV is not limited to tight junctions and that the virus might use claudin-CD81 complexes in the basolateral surface of hepatocytes to enter into the cell.20 Tight junctions are multiprotein complexes that seal the space between adjacent cells. In fact, hepatocyte plasma membranes are separated by tight junctions into sinusoidal-basolateral and apical domains.21 These two domains are very important for hepatocytes to perform diverse functions, such as canalicular bile secretion and simultaneous sinusoidal secretion of serum proteins into blood. Because the tight-junction proteins claudin-1 and occludin are thought to be a relevant part of HCV entry into hepatocytes, our goal was to characterize (1) the expression pattern of these proteins in liver tissue of patients undergoing LT, (2) their influence on early HCV kinetics following recurrent hepatitis C and their potential changes following HCV infection of the graft.