title: Endothelial arginine resynthesis contributes to the maintenance of vasomotor function in male diabetic mice.
abstract: OBJECTIVE
  Argininosuccinate synthetase (ASS) is essential for recycling L-citrulline, the by-product of NO synthase (NOS), to the NOS substrate L-arginine. Here, we assessed whether disturbed arginine resynthesis modulates endothelium-dependent vasodilatation in normal and diabetic male mice.
  
  
  RESULTS
  Endothelium-selective Ass-deficient mice (Assfl/fl/Tie2Cretg/- = Ass-KOTie2) were generated by crossing Assfl/fl mice ( = control) with Tie2Cre mice. Gene ablation in endothelial cells was confirmed by immunohistochemistry. Blood pressure (MAP) was recorded in 34-week-old male mice. Vasomotor responses were studied in isolated saphenous arteries of 12- and 34-week-old Ass-KOTie2 and control animals. At the age of 10 weeks, diabetes was induced in control and Ass-KOTie2 mice by streptozotocin injections. Vasomotor responses of diabetic animals were studied 10 weeks later. MAP was similar in control and Ass-KOTie2 mice. Depletion of circulating L-arginine by arginase 1 infusion or inhibition of NOS activity with L-NAME resulted in an increased MAP (10 and 30 mmHg, respectively) in control and Ass-KOTie2 mice. Optimal arterial diameter, contractile responses to phenylephrine, and relaxing responses to acetylcholine and sodium nitroprusside were similar in healthy control and Ass-KOTie2 mice. However, in diabetic Ass-KOTie2 mice, relaxation responses to acetylcholine and endothelium-derived NO (EDNO) were significantly reduced when compared to diabetic control mice.
  
  
  CONCLUSIONS
  Absence of endothelial citrulline recycling to arginine did not affect blood pressure and systemic arterial vasomotor responses in healthy mice. EDNO-mediated vasodilatation was significantly more impaired in diabetic Ass-KOTie2 than in control mice demonstrating that endothelial arginine recycling becomes a limiting endothelial function in diabetes.
authors.affiliation: Department of Anatomy & Embryology, Maastricht University, Maastricht, the Netherlands; Department of Pharmacology, Maastricht University, Maastricht, the Netherlands; Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, the Netherlands; Nutrition, Metabolism and Toxicology (NUTRIM) of Maastricht University, Maastricht, the Netherlands.
authors.forename: Ramesh
authors.initials: R
authors.lastname: Chennupati
authors.affiliation: Department of Pharmacology, Maastricht University, Maastricht, the Netherlands; Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland.
authors.forename: Merlijn J P M T
authors.initials: MJ
authors.lastname: Meens
authors.affiliation: Department of Anatomy & Embryology, Maastricht University, Maastricht, the Netherlands; Nutrition, Metabolism and Toxicology (NUTRIM) of Maastricht University, Maastricht, the Netherlands; Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland.
authors.forename: Vincent
authors.initials: V
authors.lastname: Marion
authors.affiliation: Department of Pharmacology, Maastricht University, Maastricht, the Netherlands; Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, the Netherlands.
authors.forename: Ben J
authors.initials: BJ
authors.lastname: Janssen
authors.affiliation: Department of Anatomy & Embryology, Maastricht University, Maastricht, the Netherlands; Nutrition, Metabolism and Toxicology (NUTRIM) of Maastricht University, Maastricht, the Netherlands.
authors.forename: Wouter H
authors.initials: WH
authors.lastname: Lamers
authors.affiliation: Department of Pharmacology, Maastricht University, Maastricht, the Netherlands; Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, the Netherlands; Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark; Department of Cardiovascular and Thoracic Surgery, Odense University Hospital, Odense, Denmark.
authors.forename: Jo G R
authors.initials: JG
authors.lastname: De Mey
authors.affiliation: Department of Anatomy & Embryology, Maastricht University, Maastricht, the Netherlands; Nutrition, Metabolism and Toxicology (NUTRIM) of Maastricht University, Maastricht, the Netherlands.
authors.forename: S Eleonore
authors.initials: SE
authors.lastname: Köhler
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001119:Arginase / Q000378:metabolism; D001120:Arginine / Q000096:biosynthesis* / Q000097:blood; D001124:Argininosuccinate Synthase / Q000235:genetics*; D001794:Blood Pressure / Q000235:genetics / Q000502:physiology*; D002956:Citrulline / Q000097:blood / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000235:genetics / Q000378:metabolism*; D042783:Endothelial Cells / Q000166:cytology / Q000201:enzymology; D004727:Endothelium / Q000166:cytology / Q000201:enzymology / Q000378:metabolism; D005260:Female; D006339:Heart Rate / Q000235:genetics / Q000502:physiology*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009131:Muscle, Smooth, Vascular / Q000502:physiology; D019331:NG-Nitroarginine Methyl Ester; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D009599:Nitroprusside / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000235:genetics / Q000502:physiology; D014665:Vasodilator Agents / Q000494:pharmacology; D014666:Vasomotor System / Q000378:metabolism
chemical_list: D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D009599:Nitroprusside; D010656:Phenylephrine; D002956:Citrulline; D001120:Arginine; D019001:Nitric Oxide Synthase; C544448:Arg1 protein, mouse; D001119:Arginase; D001124:Argininosuccinate Synthase; D000109:Acetylcholine; D019331:NG-Nitroarginine Methyl Ester