title: Endothelin and vasopressin influence splanchnic blood flow distribution during and after cardiopulmonary bypass.
abstract: OBJECTIVE
  Gastrointestinal blood flow can be compromised during and after cardiopulmonary bypass. Endothelin has been shown to be involved in the intestinal microcirculatory disturbance of sepsis. The aim of the present study was to analyze the involvement of the endothelin system on intestinal blood flow regulation during cardiopulmonary bypass and the effect of vasopressin given during cardiopulmonary bypass.
  
  
  METHODS
  A total of 24 pigs were studied in 4 groups (n = 6): group I, sham; group II, ischemia/reperfusion with 1 hour of superior mesenteric artery occlusion; group III, cardiopulmonary bypass for 1 hour; and group IV, 1 hour of cardiopulmonary bypass plus vasopressin administration, maintaining the baseline arterial pressure. All the pigs were reperfused for 90 minutes. During the experiment, the hemodynamics and jejunal microcirculation were measured continuously. The jejunal mucosal expression of endothelin-1 and its receptor subtypes A and B were determined using polymerase chain reaction.
  
  
  RESULTS
  During cardiopulmonary bypass, superior mesenteric artery flow was preserved but marked jejunal microvascular impairment occurred compared with baseline (mucosal capillary density, 192.2 ± 5.4 vs 150.8 ± 5.1 cm/cm(2); P = .005; tissue blood flow, 501.7 ± 39.3 vs 332.3 ± 27.9 AU; P = .025). The expression of endothelin-1 after cardiopulmonary bypass (3.2 ± 0.4 vs 12.2 ± 0.8 RQ, P = .006) and endothelin subtype A (0.7 ± 0.2 vs 2.4 ± 0.6 RQ; P = .01) was significantly increased compared to the sham group. Vasopressin administration during cardiopulmonary bypass led to normal capillary density (189.9 ± 3.9 vs 178.0 ± 6.3; P = .1) and tissue blood flow (501.7 ± 39.3 vs 494.7 ± 44.4 AU; P = .4) compared with baseline. The expression of endothelin-1 (3.2 ± 0.4 vs 1.8 ± 0.3 RQ; P = .3) and endothelin subtype A (0.7 ± 0.2 vs 0.9 ± 0.2 RQ; P = .5) was not different from the sham group.
  
  
  CONCLUSIONS
  Cardiopulmonary bypass leads to microvascular impairment of jejunal microcirculation, which is associated with the upregulation of endothelin-1 and endothelin subtype A. The administration of vasopressin minimizes these cardiopulmonary bypass-associated alterations.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, University Hospital of Saarland, Homburg/Saar, Germany.
authors.forename: Hagen
authors.initials: H
authors.lastname: Bomberg
authors.forename: Benjamin
authors.initials: B
authors.lastname: Bierbach
authors.forename: Stephan
authors.initials: S
authors.lastname: Flache
authors.forename: Isabell
authors.initials: I
authors.lastname: Wagner
authors.forename: Lena
authors.initials: L
authors.lastname: Gläser
authors.forename: Heinrich V
authors.initials: HV
authors.lastname: Groesdonk
authors.forename: Michael D
authors.initials: MD
authors.lastname: Menger
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Schäfers
mesh_terms: D000818:Animals; D001706:Biopsy; D001783:Blood Flow Velocity / Q000187:drug effects; D002196:Capillaries / Q000187:drug effects* / Q000378:metabolism; D002315:Cardiopulmonary Bypass / Q000009:adverse effects; D019332:Endothelin-1 / Q000235:genetics / Q000378:metabolism*; D007511:Ischemia / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control; D007583:Jejunum / Q000098:blood supply*; D017538:Mesenteric Artery, Superior / Q000187:drug effects* / Q000378:metabolism; D065666:Mesenteric Ischemia; D008833:Microcirculation / Q000187:drug effects*; D023421:Models, Animal; D012333:RNA, Messenger / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D044022:Receptor, Endothelin A / Q000235:genetics / Q000378:metabolism; D044023:Receptor, Endothelin B / Q000235:genetics / Q000378:metabolism; D012039:Regional Blood Flow / Q000187:drug effects; D013152:Splanchnic Circulation / Q000187:drug effects*; D034421:Sus scrofa; D013997:Time Factors; D014652:Vascular Diseases / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control; D014667:Vasopressins / Q000494:pharmacology*
chemical_list: D019332:Endothelin-1; D012333:RNA, Messenger; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D014667:Vasopressins