AQP-3 in the Epidermis of Haemodialysis Patients with CKD-Associated Pruritus is Overexpressed

Abstract

Background: Xerosis is considered to be one of the causes of chronic kidney disease-associated pruritus (CKD-aP). In the present study, the relationship between CKD-aP and aquaporin-3 (AQP-3), the water channel in the skin was examined in light of xerosis. Methods: AQP-3 expression in the epidermis and patients characteristics included stratum corneum hydration (SCHy) were compared in haemodialysis patients (HD-pts) without pruritus (n = 23), HD-pts with slight to mild pruritus (n = 12), and HD-pts with moderate to severe pruritus (n = 7). Results: In HD-pts, there was association between CKD-aP and both range and intensity of epidermal AQP-3 expression. The range and intensity of AQP-3 expression in the skin was significantly greater in HD-pts with severe CKD-aP than in HD-pts without CKD-aP, as shown by anti- AQP-3 staining that was both more intense and extended to more superficial layers of the skin. Conclusions: CKD-aP was shown to be associated with epidermal AQP-3 expression but not with xerosis, which was quantified in this study using SC-Hy. In addition, there was no association between xerosis and epidermal AQP-3 expression. These results indicate that xerosis, which has been considered to be a cause of CKD-aP, is not a necessary and sufficient condition for CKD-aP, and that the mechanism of the onset of xerosis may not involve epidermal AQP-3 in HD-pts.