Assessment of urinary podocalyxin as a biomarker of early diagnosis of hypertensive nephropathy

Abstract

Chronically high blood pressure-related kidney injury is known as hypertensive nephropathy (HN). Podocyte damage in the pathogenesis of this disease can result in the release of the sialoglycoprotein podocalyxin into the urine, so podocalyxin may be useful in the early diagnosis of HN. The purpose of the study was to examine the relationships between urine podocalyxin level and clinical and biochemical parameters in individuals with HN and to assess the diagnostic utility of urinary podocalyxin as an early marker of HN. Participants (114 individuals) were enrolled in this cross-sectional study, including 30 healthy controls and 84 patients with clinically proven chronic hypertension (CH). Biochemical tests were performed on the blood samples. Urinary microalbumin and creatinine levels were measured using immunoturbidimetric and spectrophotometric methods, respectively; urinary podocalyxin level was estimated with ELISA. All CH patients were classified into subgroups according to urine microalbumin/creatinine ratio (UM/CR) and the stage of chronic kidney disease (CKD). The results obtained showed that urinary podocalyxin level was significantly increased in both UM/CR and CKD staging subgroups compared with the healthy control group. A gradual increase in urinary podocalyxin level with CKD stage, especially in IV and V stages, and the higher sensitivi­ty of urinary podocalyxin as compared to UM/CR ratio in early detection of HN was demonstrated. It was concluded that urinary podocalyxin may be an important and highly sensitive marker for early diagnosis of hypertensive nephropathy in patients with chronic hypertension. Keywords: creatinine, diagnostic marker, hypertensive nephropathy, microalbumin, podocalyxin, urine