Hemodynamic, biochemical and morphological changes induced by aminoguanidine in normal and septic sheep.
OBJECTIVE
To define the acute hemodynamic, metabolic, and morphological changes induced by aminoguanidine, a selective iNOS inhibitor, in septic sheep.


METHODS
Prospective, nonrandomized animal study.


METHODS
Animal research facility in a University Hospital.


METHODS
Adult sheep, sedated and mechanically ventilated, were monitored with a pulmonary arterial catheter and an ultrasonic blood flow probe in the mesenteric artery, to measure the systemic (Q(TOT)I) and the mesenteric (Q(MES)I) blood flow indices, and an ileal tonometer. Four groups of sheep were studied: nonseptic, septic, nonseptic treated with aminoguanidine, and septic treated with aminoguanidine (100 mg kg(-1) h(-1)) (n = 6 for each group). Sepsis was induced by the intravenous administration of E. coli. Hemodynamic and biochemical parameters were measured during 300 min. Histological changes in the liver and small intestinal mucosa were analyzed at the end of the experiment.


RESULTS
In nonseptic animals, aminoguanidine slightly increased mean systemic arterial pressure (MAP), decreased Q(TOT)I, and increased vascular resistance index (SVRI) and pulmonary vascular resistance index. Q(MEs)I did not change and Q(MES)I/Q(ToT)I increased. Aminoguanidine also induced intestinal intramucosal hypercarbia, hyperlactatemia, acidemia, hypoglycemia, and morphological signs indicative of tissue ischemia in the small intestinal mucosa. In septic sheep, aminoguanidine increased SVRI and MAP only at 4 h after the septic challenge and thereafter, and worsened gas exchange.


CONCLUSIONS
In this model, exogenous administration of aminoguanidine induces beneficial hemodynamic effects 4 h after the septic challenge. In normal animals, however, aminoguanidine was associated with hypoglycemia, acidosis, hyperlactatemia, and intestinal mucosal ischemia.
Lorente
J A
JA
Servicio de Cuidados Intensivos, Hospital Universitario de Getafe, Madrid, Spain. j.a.lorente@teleline.es
Tejedor
C
C
Delgado
M A
MA
Fernández-Segoviano
P
P
Jara
N
N
Tobalina
R
R
Rodríguez-Corcos
A
A
Moscoso
A
A
Esteban
A
A
D000138:Acidosis / Q000139:chemically induced; D000704:Analysis of Variance; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D016022:Case-Control Studies; D004791:Enzyme Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D006146:Guanidines / Q000494:pharmacology* / Q000627:therapeutic use; D006439:Hemodynamics / Q000187:drug effects*; D007003:Hypoglycemia / Q000139:chemically induced; D007413:Intestinal Mucosa / Q000098:blood supply / Q000187:drug effects; D007511:Ischemia / Q000139:chemically induced; D007785:Lactose / Q000097:blood; D009102:Multiple Organ Failure / Q000517:prevention & control; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D011446:Prospective Studies; D018805:Sepsis / Q000188:drug therapy*; D012756:Sheep; D013997:Time Factors; D014655:Vascular Resistance / Q000187:drug effects; D014661:Vasoconstriction / Q000187:drug effects
D004791:Enzyme Inhibitors; D006146:Guanidines; D019001:Nitric Oxide Synthase; D007785:Lactose; C004479:pimagedine