Serum Neutrophil Gelatinase-Associated Lipocalin Levels in Patients with Non-Dipper Hypertension

Abstract

Purpose: Neutrophil gelatinase-associated lipocalin (NGAL) is a protein belonging to the lipocalin superfamily and plays a role in atherosclerosis, renal injury and inflammation. The present study aimed to investigate serum NGAL concentrations in groups of patients with dipper and non-dipper hypertension (HT) and to characterize the relationship between NGAL concentration and circadian blood pressure in hypertensive patients. Methods: A total of 41 (22 male, 19 female, mean age: 56.1 +/- 8.9 years) non-dipper HT patients, 40 (19 male, 21 female, mean age: 54.0 +/- 10.0 years) dipper HT patients and 42 age-and gender-matched healthy individuals were enrolled in the study. Dipper and non-dipper HT were diagnosed via ambulatory blood pressure monitoring. Serum NGAL concentrations were measured by enzyme-linked immunosorbent assay from blood samples obtained from patients. Results: Serum NGAL concentrations were found to be significantly higher in the non-dipper and dipper HT patient groups in comparison with the control group (84.9 +/- 23.0 ng/ml and 62.1 +/- 17.8 vs. 46.6 +/- 13.7 ng/ml, p < 0.017, respectively). Moreover, serum NGAL concentrations were significantly higher in the non-dipper HT group in comparison with the dipper HT group (p<0.017). Serum NGAL concentration showed significant correlation with overall ambulatory BP levels both in non-dipper and dipper HP groups. Conclusion: Serum NGAL concentrations increased significantly in non-dipper HT patients in comparison with dipper HT patients and normotensive patients and show significant correlation with ambulatory BP levels. Serum NGAL concentration might be a useful marker in identifying HT patients with higher risk for cardiovascular mortality.