The Relationship between Kidney Shear Wave Speed Measured Using the Elastpq Technique and Different Biomarkers of Chronic Kidney Disease

Abstract

The present study aims to find a relationship between kidney shear wave speed (KSWS) measured using Elastography Point Quantification (ElastPQ) and different biomarkers of chronic kidney disease (CKD): a tubular injury marker- kidney injury molecule-1 (KIM-1), a marker of interstitial inflammation- urinary monocyte chemoattractive protein 1 (MCP1), markers of fibrogenesis- connective tissue growth factor (CTGF), and soluble Klotho, that inhibits fibrogenesis, as a pleiotropic effect. Our study included 38 patients (mean age 56.5+/-16.12 years; 19 female, 19 male) with diabetic kidney disease. In all patients KSWS was measured using ElastPQ (Philips Affinity) and median values of 5 valid KSWS measurements were calculated and expressed in meters/second (m/s). In all patients we assessed renal function- glomerular filtration rate (eGFR), and using an ELISA method, serum levels of: KIM-1, CTGF, klotho, and urinary levels of MCP1. We obtained a mean KSWS of 0.98+/-0.40 m/s (right kidney) and 0.90+/-0.37 m/s (left kidney). KSWS was significantly lower in male vs. female subjects (0.77 vs. 1.02 m/s, p=0.05), and in patients with eGFR < 60ml/min (0.8 vs. 1.1 m/s, p=0.05). KSWS showed also a decrease with age (r=-0.53, p=0.0009). We found a statistically significant correlation of KSWS with urinary MCP1 (r=0.34, p=0.05), and with the level of sKlotho (r=0.56, p=0.03), but no correlation with CTGF and KIM-1. Our study shows that KSWS is decreased in advanced stages of CKD, and this decreased levels are associated to reduced interstitial infiltration (urinary MCP1) and probably to increased interstitial fibrosis (low soluble Klotho).