title: ACE2 deficiency modifies renoprotection afforded by ACE inhibition in experimental diabetes.
abstract: OBJECTIVE
  The degradation of angiotensin (Ang) II by ACE2, leading to the formation of Ang 1-7, is an important step in the renin-angiotensin system (RAS) and one that is significantly altered in the diabetic kidney. This study examines the role of ACE2 in early renal changes associated with diabetes and the influence of ACE2 deficiency on ACE inhibitor-mediated renoprotection.
  
  
  METHODS
  Diabetes was induced by streptozotocin in male c57bl6 mice and ACE2 knockout (KO) mice. After 5 weeks of study, animals were randomized to receive the ACE inhibitor perindopril (2 mg x kg(-1) x day(-1)). Wild-type mice were further randomized to receive the selective ACE2 inhibitor MLN-4760 (10 mg x kg(-1) x day(-1)) and followed for an additional 5 weeks. Markers of renal function and injury were then assessed.
  
  
  RESULTS
  Induction of diabetes in wild-type mice was associated with a reduction in renal ACE2 expression and decreased Ang 1-7. In diabetic mice receiving MLN-4760 and in ACE2 KO mice, diabetes-associated albuminuria was enhanced, associated with an increase in blood pressure. However, renal hypertrophy and fibrogenesis were reduced in diabetic mice with ACE2 deficiency, and hyperfiltration was attenuated. Diabetic wild-type mice treated with an ACE inhibitor experienced a reduction in albuminuria and blood pressure. These responses were attenuated in both diabetic ACE2 KO mice and diabetic mice receiving MLN-4760. However, other renoprotective and antifibrotic actions of ACE inhibition in diabetes were preserved in ACE2-deficient mice.
  
  
  CONCLUSIONS
  The expression of ACE2 is significantly modified by diabetes, which impacts both pathogenesis of kidney disease and responsiveness to RAS blockade. These data indicate that ACE2 is a complex and site-specific modulator of diabetic kidney disease.
authors.affiliation: Danielle Alberti Memorial Centre for Diabetes Complications, Baker Medical Research Institute, Melbourne, Australia.
authors.forename: Chris
authors.initials: C
authors.lastname: Tikellis
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Bialkowski
authors.forename: Josepha
authors.initials: J
authors.lastname: Pete
authors.forename: Karen
authors.initials: K
authors.lastname: Sheehy
authors.forename: Qui
authors.initials: Q
authors.lastname: Su
authors.forename: Colin
authors.initials: C
authors.lastname: Johnston
authors.forename: Mark E
authors.initials: ME
authors.lastname: Cooper
authors.forename: Merlin C
authors.initials: MC
authors.lastname: Thomas
mesh_terms: D000085962:Angiotensin-Converting Enzyme 2; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D003922:Diabetes Mellitus, Type 1 / Q000503:physiopathology*; D003930:Diabetic Retinopathy / Q000517:prevention & control*; D007668:Kidney / Q000187:drug effects / Q000201:enzymology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D007703:Peptidyl-Dipeptidase A / Q000172:deficiency / Q000378:metabolism*; D020913:Perindopril / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D007703:Peptidyl-Dipeptidase A; C000705328:Ace2 protein, mouse; D000085962:Angiotensin-Converting Enzyme 2; D020913:Perindopril