Abstract
Neutrophil gelatinase-associated lipocalin (NGAL) is upregulated systemically and by renal tubular cells in response to inflammation and ischemia. Recent interests in NGAL have focused on its ability to predict worsening renal function. However, as an iron-regulatory glycoprotein, the relationship between systemic NGAL levels and indices of anemia has not been examined. In 130 patients with chronic systolic heart failure, the authors examined the relationship between plasma NGAL levels and indices of anemia independent of underlying renal function and systemic markers of inflammation and oxidant stress. Plasma NGAL levels were significantly elevated in patients with anemia vs without anemia (121 [interquartile range, 98-197] vs 72 [interquartile range, 57-98] ng/mL, P<.001). Plasma NGAL levels were inversely correlated with indices of anemia including red blood cell count (r=-0.38, P<.0001), hemoglobin (r=-0.41, P<.0001), and red cell distribution width (r=0.25, P=.007), even in patients with relatively preserved renal function (estimated glomerular filtration rate ≥60 mL/min/1.73 m(2) ; n=83, P<.05 for all). Higher plasma NGAL levels were associated with presence of anemia independent of estimated glomerular filtration rate, plasma high-sensitivity C-reactive protein, and myeloperoxidase levels (odds ratio, 2.38; 95% confidence interval, 1.02-6.20; P=.045). Hence, systemic NGAL levels are independently associated with indices of anemia.