Association between Serum Dickkopf-1 (DKK-1) Glycoprotein and Calcific Deposits on Cardiac Valves and Carotid Intimal-Medial Thickness in Hemodialysis Patients

Abstract

Background: Cardiac valve calcification (CVC) is common in hemodialysis (HD) patients, and associated with cardiovascular and all-cause mortality. Once believed to be a passive process, it is now understood that the Wnt signaling pathway has a major role. The aim of the current study was to assess the relationship between circulating DKK-1, a negative regulator of the Wnt signaling pathway, and CVC, as well as carotid intimal-medial thickness (CIMT) in HD patients. Methods: We enrolled 74 consecutive adults on maintenance HD. Echocardiographic calcification of the mitral valve (MV) and aortic valve (AV) were detected according to Wilkins score (range 0–4), and the study of Tenenbaum et al. [Int J Cardiol. 2004 Mar;94(1):7–13] (range 0–4), respectively. CVC severity was calculated by a supposed score (range 0–8) that represents the sum of calcification grade of MV and AV. CVC severity was classified into absent (CVC score = 0), mild (CVC score = 1–2), moderate (CVC score = 3–4), and severe (CVC score ≥5). Demographic and biochemical data were collected in addition to serum DKK-1 levels and CIMT. Results: CVC was present in 67 patients (91.0%). There was a highly significant negative correlation between serum DKK-1 level and CVC score (r = –0.492; p ≤ 0.001), as well as CIMT (r = –0.611; p ≤ 0.001). Age and CIMT were independent determinants of CVC. Conclusions: CVC is almost present in all HD patients. DKK-1 seems to have a direct relation with CVC and CIMT in HD patients. Age is the strongest independent determinant of CVC.