Hypertension still remains one of the leading causes of end-stage renal disease and early detection of kidney injury may have a dramatic impact on treatment strategy and patient's prognosis. The aim of the present study was to assess whether novel biomarkers may facilitate early detection of kidney injury in patients with different severity of hypertension.Design and method:
Urine levels of neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), liver fatty-acid binding protein (L-FABP) and serum levels of Cystatin C and creatinine were measured by quantitative enzyme immunoassay in 92 hypertensive patients, divided into four age and sex-matched groups according to severity of hypertension: 1 grade (n = 24), 2 grade (n = 26), 3 grade (n = 17) and resistant hypertension (n = 25). Glomerular filtration rate (GFR) was estimated by MDRD and CKD-EPI formulas. Instrumental examination was performed after 5 days of discontinuation of antihypertensive medications and included ambulatory blood pressure monitoring (ABPM, SpaceLabs 90207).Results:
There were no differences in NGAL, KIM-1, creatinine levels, and eGFR between groups. Patients with 1, 2, 3 grades of hypertension had no differences in Cystatin C (0.86 +/- 0.1; 0.85 +/- 0.14; 0.86 +/- 0.06 pg/ml respectively; p > 0.05) and L-FABP (1997.8 +/- 1657.2; 2412.5 +/- 1487.1; 1756.7 +/- 1949.8 pg/ml respectively; p > 0.05) levels. While patients with resistant hypertension are predisposed to advanced organ damage were characterized by higher Cystatin C (0.97 +/- 0.18 pg/ml; p = 0.01) and L-FABP (9270.2 +/- 30394.5 pg/ml; p = 0.05) levels, associated with mean 24-hours systolic blood pressure (BP) level (r = 0.246, p = 0.03 and r = 0.339, p = 0.006 respectively).Conclusions:
Cystatin C and L-FABP seem to be potentially more sensitive biomarkers of kidney injury, and their levels increase with the severity of hypertension.