Caspase inhibition reduces cardiac myocyte dyshomeostasis and improves cardiac contractile function after major burn injury.
In the heart, thermal injury activates a group of intracellular cysteine proteases known as caspases, which have been suggested to contribute to myocyte inflammation and dyshomeostasis. In this study, Sprague-Dawley rats were given either a third-degree burn over 40% total body surface area plus conventional fluid resuscitation or sham burn injury. Experimental groups included 1) sham burn given vehicle, 400 microl DMSO; 2) sham burn given Q-VD-OPh (6 mg/kg), a highly specific and stable caspase inhibitor, 24 and 1 h prior to sham burn; 3) burn given vehicle, DMSO as above; 4) burn given Q-VD-OPh (6 mg/kg) 24 and 1 h prior to burn. Twenty-four hours postburn, hearts were harvested and studied with regard to myocardial intracellular sodium concentration, intracellular pH, ATP, and phosphocreatine (23Na/31P nuclear magnetic resonance); myocardial caspase-1, -3,and -8 expression; myocyte Na+ (fluorescent indicator, sodium-binding benzofurzan isophthalate); myocyte secretion of TNF-alpha, IL-1beta, IL-6, and IL-10; and myocardial performance (Langendorff). Burn injury treated with vehicle alone produced increased myocardial expression of caspase-1, -3, and -8, myocyte Na+ loading, cytokine secretion, and myocardial contractile depression; cellular pH, ATP, and phosphocreatine were stable. Q-VD-OPh treatment in burned rats attenuated myocardial caspase expression, prevented burn-related myocardial Na+ loading, attenuated myocyte cytokine responses, and improved myocardial contraction and relaxation. The present data suggest that signaling through myocardial caspases plays a pivotal role in burn-related myocyte sodium dyshomeostasis and myocyte inflammation, perhaps contributing to burn-related contractile dysfunction.
Carlson
Deborah L
DL
Department of Surgery, University of Texas Southwestern Medical Center, Dallas, TX 75390-9160, USA.
Maass
David L
DL
White
Jean
J
Sikes
Patricia
P
Horton
Jureta W
JW
D000255:Adenosine Triphosphate / Q000378:metabolism; D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology* / Q000627:therapeutic use; D000818:Animals; D002056:Burns / Q000150:complications* / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology; D002118:Calcium / Q000378:metabolism; D020170:Caspase 1 / Q000378:metabolism; D053148:Caspase 3 / Q000378:metabolism; D053181:Caspase 8 / Q000378:metabolism; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D004195:Disease Models, Animal; D006331:Heart Diseases / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control*; D006706:Homeostasis; D006863:Hydrogen-Ion Concentration; D016753:Interleukin-10 / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D010725:Phosphocreatine / Q000378:metabolism; D011804:Quinolines / Q000494:pharmacology* / Q000627:therapeutic use; D051381:Rats; D017207:Rats, Sprague-Dawley; D012720:Severity of Illness Index; D015398:Signal Transduction / Q000187:drug effects*; D012964:Sodium / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D017725:Ventricular Pressure / Q000187:drug effects
D000590:Amino Acid Chloromethyl Ketones; D061945:Caspase Inhibitors; D015853:Cysteine Proteinase Inhibitors; D053583:Interleukin-1beta; D015850:Interleukin-6; D011804:Quinolines; D014409:Tumor Necrosis Factor-alpha; C468548:quinoline-val-asp(OMe)-CH2-OPH; D010725:Phosphocreatine; D016753:Interleukin-10; D000255:Adenosine Triphosphate; D012964:Sodium; C505530:CASP8 protein, human; D053148:Caspase 3; D053181:Caspase 8; D020169:Caspases; D020170:Caspase 1; D002118:Calcium