Uromodulin and severity of tubulointerstitial lesions in patients with nephropathies

AIM OF THE STUDY. It is traditionally believed that uromodulin (Umo) may participate in urinary stone formation. However, there is evidence that Umo can be operated in other mechanisms, especially damaging tubulointerstitial renal compartment and promotional arterial hypertension. In this regard, we attempt to compare the levels of the Umo in urine and blood serum with the morphological characteristics of kidney lesions and some clinical functional parameters in patients with various nephropathies. PATIENTS AND METHODS. Twenty eight patients (Pts; M: F 11: 17) with various nephropathies, aged 28 - 74 years were examined. Everybody was performed renal biopsy with semi-quantitative assessment of renal injury severity using light-optic analysis. There were measured UMO, creatinine and urea levels in blood serum, UMO and protein concentration in urine, was estimated glomerular filtration rate (eGFR; CKD-EPI). In twenty Pts 24-hour blood pressure monitoring was performed. RESULTS. Urinary Umo concentration significantly inverse correlated (Spearmen rank correlation coefficient) with degree of tubular atrophy (TA; Rs=-0.39; P=0.038), mononuclear infiltration of interstitium (Rs=-0,37; P=0,05) and mean systolic BP at the day time (mSBPday; Rs=-0.49; P=0.028). Serum Umo concentration was directly associated with eGFR (Rs=0.53; P=0.007) and inverse - with tubular atrophy (Rs=-0.39; P=0.038), degree of perivascular stromal fibrosis (Rs=-0.44; P=0.019), Scr (Rs=-0.64; P<0.001) and serum creatinine and urea concentration (Rs=-0.60; P<0.002). TA directly correlated with mSBPday (Rs=-0.50; P<0.001). There were no associations between serum Umo concentration or urine Umo concentration and glomerular lesions or proteinuria. Serum and urine Umo concentrations didn’t correlate between each other. In the case of hyaline casts in the tubular lumen serum Umo level was significantly lower than in Pts with no casts. CONCLUSION. Umo concentrations in urine and serum are associated with the severity of tubulointerstitial lesions in patients with different nephropathies. Reduction of the urinary and serum Umo levels may reflect a decrease of nephron mass and more local tubulointerstitial lesions.

uromodulin, nephropathies, tubulointerstitial lesions

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