Myocardial protection by N,N,N-trimethylsphingosine in ischemia reperfusion injury is mediated by inhibition of P-selectin.
Polymorphonuclear leukocytes (PMNs) play an important role in myocardial ischemia/reperfusion (MI/R) injury. We examined the cardioprotective effects of N,N,N-trimethylsphingosine (TMS) in a murine model of MI (20 min) and R (24 h) injury in vivo, focusing on leukocyte-endothelial interactions. TMS is a synthetic N-methylated sphingosine derivative that has protein kinase C inhibitory activity and has been shown to prevent leukocyte activation. TMS (18 microgram/kg), administered intravenously 1 min prior to reperfusion, significantly attenuated myocardial necrotic injury assessed by myocardial creatine kinase loss compared with MI/R rats receiving only vehicle (P<0.001). Cardiac myeloperoxidase activity, an index of PMN accumulation in the ischemic myocardium, was also significantly attenuated by TMS compared with rats receiving vehicle (P<0.001). We further examined whether TMS can attenuate leukocyte-endothelial interaction by intravital microscopy. TMS significantly attenuated NG-nitro-L-arginine-methyl ester (L-NAME)-stimulated PMN rolling and adherence to the rat microvascular endothelium. This action of TMS appears to be mediated by reduction of P-selectin expression because immunohistochemical analysis demonstrated that TMS significantly attenuated endothelial P-selectin expression in the L-NAME-superfused rat mesenteric microvasculature. Similarly, TMS markedly attenuated rapid P-selectin expression in rat platelets stimulated with either thrombin or L-NAME assessed by flow cytometry. In conclusion, TMS seems to be an effective cardioprotective agent by inhibiting early leukocyte-endothelial interaction, thus preventing leukocyte accumulation in the ischemic reperfused myocardium.
Scalia
R
R
Department of Physiology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA, USA.
Murohara
T
T
Delyani
J A
JA
Nossuli
T O
TO
Lefer
A M
AM
D000818:Animals; D001792:Blood Platelets / Q000378:metabolism; D003402:Creatine Kinase / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology; D008297:Male; D008833:Microcirculation / Q000166:cytology; D009203:Myocardial Infarction / Q000188:drug therapy*; D009206:Myocardium / Q000201:enzymology; D009504:Neutrophils / Q000201:enzymology; D019007:P-Selectin / Q000378:metabolism*; D009195:Peroxidase / Q000378:metabolism; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000517:prevention & control*; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use
D019007:P-Selectin; D010975:Platelet Aggregation Inhibitors; C071600:N,N,N-trimethylsphingosine; D009195:Peroxidase; D003402:Creatine Kinase; D013110:Sphingosine