Serum neutrophil gelatinase-associated lipocalin as a marker of renal function in hypertensive and normotensive patients with coronary artery disease.

Aim: Hypertension is one of the risk factors for cardiovascular diseases. The kidneys could be a victim and/or culprit of hypertension. Recently, the value of neutrophil gelatinase-associated lipocalin (NGAL) was highlighted as a novel marker for early detection of acute renal damage. Therefore, the aim of the study was to assess whether hypertension could affect NGAL and cystatin C levels in patients with normal serum creatinine (lower than 1.5 mg/dL in males and 1.2 mg/dL in females) and stable coronary artery disease.
Methods: Serum, urinary NGAL, cystatin C and estimated glomerular filtration rate (eGFR; Modification of Diet in Renal Disease study (MDRD) and Cockcroft-Gault formulas) were evaluated in hypertensive, normotensive patients with stable coronary heart disease and healthy volunteers.
Results: Normotensives had significantly lower NGAL than hypertensives. Serum cystatin C was significantly lower in normotensives than in hypertensives. Urinary NGAL did not differ significantly between these groups. Despite similar serum creatinine levels, eGFR (MDRD and Cockcroft-Gault formulas) was significantly higher in normotensives than in hypertensives. Serum NGAL was related, in univariate analysis, to serum creatinine, urea, urinary NGAL, haemoglobin, haematocrit, duration of hypertension, age, eGFR by MDRD and Cockcroft-Gault, and cystatin C.
Conclusion: Hypertension is associated with kidney injury as reflected by elevated serum NGAL and cystatin C. It is noteworthy that despite normal serum creatinine, eGFR is relatively low suggesting impaired renal function. Therefore, NGAL needs to be investigated as a potential early marker for impaired kidney function/kidney injury, especially in patients with another risk factor for kidney damage, namely coronary artery disease.