Changes Of Urine Liver Fatty Acid-binding Protein(uL-FABP) And Neutrophil Gelatinase-associated Lipocalin(uNGAL) In Elderly Patients With Primary Hypertension And Their Clinical Significance

Objective: To explore the diagnostic value of urine liver-type fatty acid binding protein(u LFABP) and urinary neutrophil gelatinase-associated lipocalin(u NGAL) in early renal impairment of elderly hypertension.Moreover,investigate the relationship between them and hypertensive nephropathy.Methods: 42 cases of elderly patients with primary hypertension, from October 2014 to June2015, in Geriatrics of the First Affiliated Hospital of Medical College of Shihezi University,were recruited and divided into normal albuminuria group(NA, n = 21) and microalbuminuria group(MA, n=21) in this study.Meanwhile, 21 healthy elderly persons were enrolled as normal control(NC) group. Urinary microalbumin(Um Alb), urine creatinine(Ucr), serum creatinine(Scr) and blood urea nitrogen(BUN) were detected in our Laboratory, calculated the value of urinary albumin-to-creatinine ratio(UACR).u L-FABP and u NGAL were measured using ELISA and divided by Ucr as the final result, in order to redress the effects of urine concentration. The differences of u L-FABP and u NGAL among three groups were compared.The relationship of u L-FABP and u NGAL with UACR and estimated glomerular filtration rate(e GFR) were also analyzed. The receiver operating characteristic(ROC) curve was used to confirm the critical points and diagnostic value,which were u L-FABP and u NGAL levels in diagnosis of early renal damage in elderly patients with essential hypertension.Results:1. The uL-FABP and uNGAL levels in MA group were significantly higher than those in NA group and control group(all P<0.05).There were statistical difference in the levels of u L-FABP and u NGAL between NA group and control group(all P<0.05). 2.In elderly patients with essential hypertension, u L-FABP and u NGAL were all negatively correlated with e GFR(all P <0.05) and were positive correlated with UACR, Scr and BUN(all P <0.05). 3.According to the ROC curve using UACR as a reference and 18mg/g as the cutoff point, the best u L-FABP cut-off value of diagnosing patients with primary hypertension and early renal impairment was 25.06ug/g ? Cr,sensitivity was 81% and specificity was 76.2%, and the area under the ROC curve was 0.838(P <0.05);the best u NGAL cut-off value was 49.79ug/g?Cr,sensitivity was 85.7% and specificity was 42.9%, and the area under the ROC curve was 0.683(P <0.05).Conclusion: 1.uL-FABP and uNGAL appear earlier than microalbuminuria in elderly patients with essential hypertension, they may be markers for early renal damage in elderly hypertensive patients. 2.Performance of u L-FABP is much stronger than that of u NGAL in diagnosis of elderly hypertensive patients with early renal damage. 3. u L-FABP and u NGAL had an upward trend with the progression of hypertensive renal damage, they are helpful for monitoring the progression of renal damage in elderly hypertensive patients.