title: Chronic renovascular hypertension is associated with elevated levels of neutrophil gelatinase-associated lipocalin.
abstract: BACKGROUND
  Renovascular hypertension (RVH) is characterized by chronic inflammation of the stenotic kidney and progressive renal dysfunction. Neutrophil gelatinase-associated lipocalin (NGAL), an acute phase protein induced in inflammatory conditions and ischemia, is a novel biomarker for acute kidney injury. We hypothesized that chronic RVH would be associated with increased renal and circulating NGAL levels.
  
  
  METHODS
  We prospectively measured renal vein and inferior vena cava (IVC) levels of NGAL and inflammatory cytokines in essential hypertensive (EH) and RVH patients, during constant sodium intake and anti-hypertensive regimens, and compared them with systemic levels in age-matched normotensive subjects (n = 22 each). In addition, we measured urinary NGAL and kidney injury molecule (KIM)-1 in all patients.
  
  
  RESULTS
  Blood pressure, serum creatinine, estimated glomerular filtration rate (eGFR), lipid panels and medications were similar in RVH and EH. Systemic, stenotic and contralateral renal vein levels of NGAL were all similarly elevated in RVH versus normal hypertension and EH (P < 0.05), as were renal vein levels of inflammatory markers like tumor necrosis factor-α. Furthermore, renal vein NGAL levels inversely correlated with eGFR, and directly with renal vein (but not systemic) levels of inflammatory markers. Urinary levels of NGAL and KIM-1 were elevated in both EH and RVH, as were systemic levels of C-reactive protein.
  
  
  CONCLUSIONS
  Chronic RVH is associated with elevated NGAL levels, likely due to ongoing kidney and systemic inflammation and ischemia. These findings may also imply the occurrence of the inflammation process in chronic RVH, which might contribute to the poorer outcomes of RVH compared with EH patients.
authors.affiliation: Division of Nephrology and Hypertension, Department of Internal Medicine, Mayo Clinic, Rochester, MN, USA.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Eirin
authors.forename: Monika L
authors.initials: ML
authors.lastname: Gloviczki
authors.forename: Hui
authors.initials: H
authors.lastname: Tang
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Rule
authors.forename: John R
authors.initials: JR
authors.lastname: Woollard
authors.forename: Amir
authors.initials: A
authors.lastname: Lerman
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Textor
authors.forename: Lilach O
authors.initials: LO
authors.lastname: Lerman
mesh_terms: D000209:Acute-Phase Proteins / Q000652:urine; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood* / Q000652:urine; D002097:C-Reactive Protein; D016207:Cytokines / Q000097:blood*; D005260:Female; D000072596:Hepatitis A Virus Cellular Receptor 1; D006801:Humans; D006978:Hypertension, Renovascular / Q000097:blood* / Q000503:physiopathology; D007668:Kidney / Q000098:blood supply* / Q000378:metabolism; D000071068:Lipocalin-2; D054834:Lipocalins / Q000097:blood* / Q000652:urine; D008297:Male; D008562:Membrane Glycoproteins / Q000652:urine*; D008875:Middle Aged; D011446:Prospective Studies; D011518:Proto-Oncogene Proteins / Q000097:blood* / Q000652:urine; D011991:Receptors, Virus; D012082:Renal Veins
chemical_list: D000209:Acute-Phase Proteins; D015415:Biomarkers; D016207:Cytokines; C491143:HAVCR1 protein, human; D000072596:Hepatitis A Virus Cellular Receptor 1; C489506:LCN2 protein, human; D000071068:Lipocalin-2; D054834:Lipocalins; D008562:Membrane Glycoproteins; D011518:Proto-Oncogene Proteins; D011991:Receptors, Virus; D002097:C-Reactive Protein