title: Serum HSP27 is associated with medullary perfusion in kidney allografts.
abstract: BACKGROUND
  Heat shock protein 27 (HSP27) is a small HSP up-regulated in response to stress in the kidney. The relationship between HSP27 and intrarenal oxygenation in patients with native and transplant kidney disease is unknown.
  
  
  METHODS
  We compared HSP27 levels, intrarenal oxygenation measured by blood oxygen-level dependent (BOLD) imaging using R(2)* values, and perfusion determined by arterial spin labeling (ASL) magnetic resonance imaging (MRI), between patients with native and transplant kidney disease (n=28).
  
  
  RESULTS
  There were no statistical differences in mean age (53.9 vs. 47.1 years), kidney function (63.6 vs. 50.7 ml/min per 1.73 m(2)), mean arterial blood pressure (91.6 vs. 91.1 mm Hg), hematocrit (40.6% vs. 39.3%), diuretic or angiotensin-converting enzyme inhibitor use, serum or urine levels of hydrogen peroxide, nitric oxide, F(2) isoprostanes and HSP27 between native and transplant kidneys. BOLD-MRI studies demonstrated comparable patterns in intrarenal oxygen bioavailability (medullary R(2)* 18.1 vs. 18.3/s and cortical R(2)* 12 vs. 11.7/s, respectively). However, medullary perfusion was significantly lower in transplant kidneys (36.4 vs. 78.7 ml/100 g per minute, p=0.0002). There was a linear relationship between serum HSP27 concentrations and medullary perfusion in kidney allografts (HSP27 concentration [ng/mL] = 0.78 + 0.09 medullary perfusion, R(2)=0.43, p=0.01).
  
  
  CONCLUSIONS
  Our study demonstrates that medullary perfusion is significantly lower in kidney allografts compared with native kidneys with comparable renal function. We further noted a direct association between serum HSP27 levels and medullary perfusion after transplantation. Additional studies are needed to examine the role of HSP27 as a biomarker of kidney disease progression.
authors.affiliation: Nephrology Department, Hospital Del Mar, Barcelona, Spain.
authors.forename: Eva
authors.initials: E
authors.lastname: Marquez
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Sadowski
authors.forename: Shannon
authors.initials: S
authors.lastname: Reese
authors.forename: Aparna
authors.initials: A
authors.lastname: Vidyasagar
authors.forename: Nathan
authors.initials: N
authors.lastname: Artz
authors.forename: Sean
authors.initials: S
authors.lastname: Fain
authors.forename: Lynn
authors.initials: L
authors.lastname: Jacobson
authors.forename: William
authors.initials: W
authors.lastname: Swain
authors.forename: Arjang
authors.initials: A
authors.lastname: Djamali
mesh_terms: D000328:Adult; D000368:Aged; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use; D062186:Arterial Pressure; D015415:Biomarkers / Q000097:blood / Q000652:urine; D016009:Chi-Square Distribution; D003404:Creatinine / Q000097:blood; D018450:Disease Progression; D004232:Diuretics / Q000627:therapeutic use; D028441:F2-Isoprostanes / Q000652:urine; D005260:Female; D005919:Glomerular Filtration Rate; D055551:HSP27 Heat-Shock Proteins / Q000097:blood* / Q000652:urine; D006360:Heat-Shock Proteins; D006400:Hematocrit; D006801:Humans; D006861:Hydrogen Peroxide / Q000097:blood / Q000652:urine; D007679:Kidney Medulla / Q000098:blood supply*; D016030:Kidney Transplantation / Q000009:adverse effects*; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D018832:Molecular Chaperones; D009569:Nitric Oxide / Q000097:blood / Q000652:urine; D018384:Oxidative Stress; D010100:Oxygen / Q000097:blood; D055420:Perfusion Imaging / Q000379:methods; D011237:Predictive Value of Tests; D012079:Renal Circulation; D051436:Renal Insufficiency, Chronic / Q000097:blood* / Q000209:etiology / Q000503:physiopathology* / Q000652:urine; D013113:Spin Labels
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D015415:Biomarkers; D004232:Diuretics; D028441:F2-Isoprostanes; D055551:HSP27 Heat-Shock Proteins; C057725:HSPB1 protein, human; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D013113:Spin Labels; D009569:Nitric Oxide; D003404:Creatinine; D006861:Hydrogen Peroxide; D010100:Oxygen