Calcium Kidney Stones are Associated with Increased Risk of Carotid Atherosclerosis: The Link between Urinary Stone Risks, Carotid Intima-Media Thickness, and Oxidative Stress Markers

Abstract

Previous studies have suggested that kidney stone formers are associated with a higher risk of cardiovascular events. To our knowledge, there have been no previous examinations of the relationship between carotid intima-media thickness (IMT) and urinary stone risk factors. This study was aimed toward an investigation of the association between dyslipidemia, IMT, and 24-hour urinalysis in patients with calcium oxalate (CaOx) or calcium phosphate (CaP) stones. We prospectively enrolled 114 patients with kidney stones and 33 controls between January 2016 and August 2016. All patients were divided into four groups, according to the stone compositions-CaOx ≥ 50% group, CaP group, struvite group, and uric acid stones group. Carotid IMT and the carotid score (CS) were evaluated using extracranial carotid artery doppler ultrasonography. The results of a multivariate analysis indicated that a higher serum total cholesterol (TC) and low-density lipoprotein (LDL) were all associated with lower urinary citrate and higher CS in both the CaOx ≥ 50% and CaP groups. Higher serum TC and LDL were also associated with increased serum 8-OHdG levels in both groups. The levels of carotid IMT and CS in the CaOx ≥ 50% and CaP groups were all significantly higher than in the controls. These findings suggest a strong link between dyslipidemia, carotid atherosclerosis, and calcium kidney stone disease.

Keywords: atherosclerosis; carotid intima-media thickness; hypercholesteremia; hyperlipidemia; kidney stone; oxidative stress.

Figure 1

Carotid score and intima-media thickness (IMT) of carotid artery ultrasonographic scans in the different stone groups. *: p < 0.05 carotid score was significantly different when compared with the control. #: p < 0.05 IMT was significantly different when compared with the control. Abbreviation: CaOx, Calcium oxalate; CaP, Calcium phosphate.

Figure 2

Serum markers of inflammation and oxidative stress compared to the controls in stone patients with CaOx and CaP, respectively. (The Nitro Tyrosine data was reduced 100X; IL-6 was magnified 10X, and neutrophil gelatinase associated lipocalin (NGAL) was reduced 100X from the original values in Figure 2A–C. (A), TC > 200, (B), HDL ≤ 40, (C) LDL ≥ 100. (D). Correlation between serum 8-OHDG and VCAM1; (E). Correlation between serum 8-OHdG and IL-6; (F). Correlation between urinary Oxalate level and serum NGAL level.