BIOMARKERS OF KIDNEY DAMAGE IN PATIENTS WITH ARTERIAL HYPERTENSION

Involving of renal tubulointerstitial tissue (TIT) with fibrosis development plays an important role in the persistent renal dysfunction. This circumstance gave rise to the attempts of neutrophil gelatinase–associated lipocalin (NGAL), interleukin–18 (IL–18) use to estimate kidney TIT lesion in chronic glomerulonephritis (CGN) and essential hypertension (EH). Aim. To study the relationship between the biomarkers and clinical, morphological parameters reflecting renal TIT damage in CGN and EH patients. Materials and methods. We examined 44 hypertensive patients and 49 patients with CGN and hypertension. We used data of the kidney morphological study for the analysis of renal TIT lesion in CGN patients. Levels of blood and urine NGAL and IL–18 were determined using immunoassay kits. Results. All patients had preserved renal function. In hypertensive patients microalbuminuria (MAU) was detected in 32%. Patients with CGN had average daily proteinuria 0,5 (0,1:1,2) g/day. Morphologically tubular epithelium dystrophy was observed in 98% ofpatients with CGN. Interstitial fibrosis (IF) was seen in all patients with CGN, and 45% had focal character, while 55% – diffuse. Necrotic changes in the tubular epithelium were observed in 69% of cases, thickening of tubular basement membrane – 61% of patients. Correlation analysis found an association between the level of serum NGAL and IF(r=0,35, p=0,05), tubular basement membrane thickening (r=0,42, p=0,05); urinary NGAL levels and tubular epithelium dystrophy (r=0,29, p=0,05). Serum IL–18 was correlated with tubular epithelium dystrophy (r=0,69, p=0,05); tubular epithelium necrosis (r=0,37, p=0,05), IF (r=0,31, p=0,05). Despite normal renal function and absence of MAU (in 64% of cases), the indicators of renal TIT damage in hypertensive patients are increased. Conclusions. Serum, urine NGAL and serum IL–18 can be used as markers of renal TIT lesion in CGN and EH patients. Serum NGAL reflects most accurately IF and tubular basement membrane changes; urine NGAL – tubular epithelium dystrophy. Serum IL–18 is an indicator of tubular epithelium necrosis, IF.