title: Functional dilatation and medial remodeling of the renal artery in response to chronic increased blood flow.
abstract: OBJECTIVE
  Renal blood flow (RBF) is tightly regulated by several intrinsic pathways in maintaining optimal kidney blood supply. Using a rat model of aortocaval (AC) fistula, we investigated remodeling of the renal artery following prolonged increased blood flow.
  
  
  METHODS
  An AC fistula was created in the infrarenal aorta of anesthetized rats, and changes of blood flow in the renal artery were assessed using an ultrasonic flow probe. Morphological changes and expression of endothelial nitric oxide synthase and matrix metalloproteinase-2 in the remodeled renal artery were analyzed.
  
  
  RESULTS
  Blood flow in the renal artery increased immediately after creation of AC fistula, but normal RBF was restored 8 weeks later. The renal artery dilated significantly 8 weeks after operation. Expression of endothelial nitric oxide synthase and matrix metalloproteinase-2 was upregulated shortly after blood flow increase, and returned to baseline levels after 3 weeks. Histological sections showed luminal dilatation with medial thickening and endothelial cell-to-smooth muscle cell attachments in the remodeled renal artery.
  
  
  CONCLUSIONS
  Increased RBF was accommodated by functional dilatation and remodeling in the medial layer of the renal artery in order to restore normal blood flow. Our results provide important mechanistic insight into the intrinsic regulation of the renal artery in response to increased RBF.
authors.affiliation: Division of Cardiovascular Surgery, Department of Surgery, National Cheng Kung University College and Hospital, Tainan, Taiwan, ROC.
authors.forename: Jun-Neng
authors.initials: JN
authors.lastname: Roan
authors.forename: Chin-Yi
authors.initials: CY
authors.lastname: Yeh
authors.forename: Wen-Cheng
authors.initials: WC
authors.lastname: Chiu
authors.forename: Chou-Hwei
authors.initials: CH
authors.lastname: Lee
authors.forename: Shih-Wei
authors.initials: SW
authors.lastname: Chang
authors.forename: Ya-Fen
authors.initials: YF
authors.lastname: Jiangshieh
authors.forename: Yu-Chuan
authors.initials: YC
authors.lastname: Tsai
authors.forename: Chen-Fuh
authors.initials: CF
authors.lastname: Lam
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D002908:Chronic Disease; D006977:Hypertension, Renal / Q000473:pathology / Q000503:physiopathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012077:Renal Artery / Q000473:pathology* / Q000502:physiology*; D012079:Renal Circulation / Q000502:physiology*; D014664:Vasodilation / Q000502:physiology*