Vesnarinone restores contractility and calcium handling in early endotoxemia.
BACKGROUND
Endotoxin (lipopolysaccharide, LPS) is a trigger of the systemic inflammatory response. We have previously found that vesnarinone and amrinone, when given before LPS, prevented cytokine production and LPS-related cardiac dysfunction. We tested the hypothesis that vesnarinone would improve intracellular Ca(2+) handling and calcium-activated contractile force after the onset of endotoxemia.


RESULTS
Adult rabbits received a bolus injection of LPS or vehicle. Vesnarinone (3 mg/kg) was given intravenously 90 minutes later. Two hours after LPS administration, hearts were perfused in the isolated Langendorff mode. Peak left ventricular developed pressure, +/-dp/dt, oxygen consumption (MVO(2)), and ratexpressure product were evaluated in conjunction with fluorescent spectroscopic determinations of intracellular calcium concentrations (Ca(i)) and the rate of Ca(i) transient decline during diastole (tauCa). Peak left ventricular developed pressure and +/-dp/dt were significantly lower in the LPS group. These were completely restored by vesnarinone. There was significantly slower diastolic calcium removal (increased tauCa) in LPS hearts that was also corrected by vesnarinone; however, the cytosolic calcium overload characteristic of LPS hearts was only partially improved. Reduced mechanical inefficiency (the ratio of rate-pressure product to MVO(2)) and myofilament sensitivity to Ca(i) were also significantly improved by vesnarinone.


CONCLUSIONS
Acute endotoxemia caused contractile protein calcium insensitivity, oxygen wastage, and abnormal calcium cycling. Vesnarinone, given in the rescue mode, normalized LPS-induced myocardial dysfunction and partially restored abnormal calcium cycling. Although the mechanisms responsible for these effects require further clarification, it appears that agents such as vesnarinone may be useful to treat inflammatory-induced myocardial dysfunction.
Takeuchi
K
K
Departments of Anesthesiology and Cardiac Surgery and the Anesthesia/Critical Care Medicine Laboratory, Children's Hospital and Harvard Medical School, Boston, MA 02115, USA.
del Nido
P J
PJ
Poutias
D N
DN
Cowan
D B
DB
Munakata
M
M
McGowan
F X
FX
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002304:Cardiac Pacing, Artificial; D002316:Cardiotonic Agents / Q000008:administration & dosage*; D004195:Disease Models, Animal; D019446:Endotoxemia / Q000139:chemically induced / Q000188:drug therapy*; D005456:Fluorescent Dyes; D006575:Heterocyclic Compounds, 3-Ring; D066298:In Vitro Techniques; D007262:Infusions, Intravenous; D007424:Intracellular Fluid / Q000378:metabolism; D008070:Lipopolysaccharides; D009200:Myocardial Contraction / Q000187:drug effects*; D010101:Oxygen Consumption; D011719:Pyrazines; D011804:Quinolines / Q000008:administration & dosage*; D011817:Rabbits; D016277:Ventricular Function, Left / Q000187:drug effects
D002316:Cardiotonic Agents; D005456:Fluorescent Dyes; D006575:Heterocyclic Compounds, 3-Ring; D008070:Lipopolysaccharides; D011719:Pyrazines; D011804:Quinolines; C068483:rhod-2; C041667:vesnarinone; D002118:Calcium