Vascular calcification is associated with Wnt-signaling pathway and blood pressure variability in chronic kidney disease rats.

Abstract

Vascular calcification (VC) is a common complication in chronic kidney disease (CKD) and has been shown to be associated with increased cardiovascular events and mortality. This study was to explore the role of Wnt-signaling pathway in CKD VC, and the association between VC and blood pressure variability (BPV) which is a risk factor of cardiovascular events. Adult male Sprague-Dawley rats were divided into adenine-induced CKD group (n = 5), 5/6 nephrectomy CKD group (n = 5), sham group (n = 5) and control group (n = 5). Low-calcium-high-phosphate diets were introduced to induce vascular calcification. Both daytime (hour-to-hour during the day) and mid-term (day-to-day for 9 days) blood pressure (BP) were collected and analyzed for BPV metrics. At sacrifice, kidney, heart and aorta samples were taken for histological analyses. Calcium deposition in aorta was identified with Alizarin Red stain and graded. Immunohistochemistry stain and western blot were performed for Wnt3a, Wnt5a, β-catenin, sclerostin, osteopontin, and α-SMA. Compared with control rats, CKD rats suffered from markedly severer VC (Grade 2.6 ± 0.2 and 1.8 ± 0.8 vs 0.0 ± 0.0 and 0.2 ± 0.4, P = .0010). VC was positively correlated with vascular Wnt3a and β-catenin expression (P = .0032 and .0000), but not significantly associated with Wnta5a or sclerostin. Besides, CKD rats showed increased BPV (P < .001), which was also positively correlated with VC. We confirmed that CKD rats had enhanced Wnt-signaling in vascular tissue and severer aorta calcification together with increased BPV. Wnt pathway may be a potential target in future VC and BPV management in CKD.