Dysmetabolic markers predict outcomes in autosomal dominant polycystic kidney disease.

BACKGROUND: Overweight and obesity were recently associated with a poor prognosis in patients with autosomal dominant polycystic kidney disease (ADPKD). Whether the metabolic consequences of obesity as defined by the metabolic syndrome (MS) are also linked with disease progression remains untested. METHODS: Eligible ADPKD patients with different stages of CKD (n = 105) and 105 non-diabetic controls matched for CKD stage were enrolled in the study. Groups were evaluated at baseline for presence of MS, blood markers of metabolism, homeostasis model assessment of insulin resistance (HOMA-IR) score, and biochemical markers of inflammation (hs-CRP, IL-1ß, IL-6, TNF-α and PON-1). MS was defined according to the National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATP III). Patients were followed for 12 months and progression defined as a decrease in baseline eGFR > 10%. RESULTS: MS and hypertension were more prevalent amongst ADPKD patients than in the control group. Meanwhile, markers of inflammation such as hs-CRP (3.63 [3.45-5.17] vs. 4.2 [3.45-8.99] mg/dL; p = 0.014), IL-6 (21.65 [14.1-27.49] vs. 24.9 [16.23-39.4] pg/mL; p = 0.004) and IL-1ß (21.33 [15.8-26.4] vs. 26.78 [18.22-35] pg/mL; p < 0.001) levels were all more elevated in ADPKD patients than in non-diabetic CKD subjects. In multivariate analysis having a truncating PKD1 mutation predicted (OR 1.25 [1.09-1.43]; p = 0.002) fulfilling the MS criteria. Finally, ADPKD patients fulfilling MS criteria had a significantly more rapid progression during 12 months of follow-up than did those that did not (OR 3.28 [1.09-9.87]; p = 0.035). CONCLUSIONS: Our data supports the notion that dysmetabolisms part of the ADPKD phenotype and associated with a poor outcome, especially in patients with a truncating PKD1 mutation.

The association of endothelin-1 levels with renal survival in polycystic kidney disease patients.

BACKGROUND: The prominent features of autosomal dominant polycystic kidney disease (ADPKD) are early development of hypertension, chronic kidney disease and cardiovascular problems. Thus, we aimed to investigate the role of endothelin, a vascular biomarker, in the clinical course of ADPKD, including renal and cardiovascular survival. METHODS: In 138 patients with ADPKD and 28 healthy controls, we measured serum endothelin-1 (ET-1) levels by enzyme-linked immunosorbent assay (ELISA). Endothelium-dependent vasodilatation (flow-mediated dilatation, FMD) and endothelium-independent vasodilatation (nitroglycerin-mediated dilatation, NMD) of the brachial artery were assessed non-invasively with high-resolution ultrasound. Magnetic resonance imaging (MRI) was performed with a 1.5-T system, and total kidney volumes were calculated using mid-slice technique. To determine PKD1 and PKD2 genotype, we performed molecular and genetic tests involving the following steps: DNA isolation, next-generation sequencing (NGS) and data analysis. RESULTS: Endothelin levels and height-adjusted total kidney volumes (hTKV) significantly increased while the estimated glomerular filtration rate (eGFR) decreased across CKD stages 1-4. Hypertension was more frequent in ADPKD patients with high serum endothelin. At multivariate Cox analysis, endothelin level, PKD1 truncating mutation, hTKV, high-sensitive C reactive protein (hs-CRP) level and the presence of diabetes mellitus were associated with the risk of overall survival. Moreover, endothelin level, PKD1 truncating mutation, hTKV, age and presence of hypertension were associated with the risk of renal survival. Additionally, body mass index (BMI), FMD, PKD1 truncating mutation, endothelin and triglyceride levels were independently associated with hypertension. CONCLUSIONS: Increased serum endothelin levels independently predict hypertension in ADPKD. Serum endothelin levels are also associated with both renal and overall survival in patients with ADPKD.