Endothelin gene expression during ischemia and reperfusion.
Endothelin-1 (ET-1) probably plays an important role in myocardial damage in acute ischemia. Coronary sinus ET-1 and its precursor big endothelin-1 (big ET-1) levels and also tissue levels of preproendothelin-1 mRNA (ET-1 mRNA) were investigated in an in vivo canine ischemia-reperfusion model in nine consecutive mongrel dogs, surviving 30-minute ligation of the left descending coronary artery followed by a 90-minute reperfusion period. Samples were collected before and at the end of ischemia and during reperfusion. ET-1 and big ET-1 were obtained by immunoprecipitation and detected by western blotting. The ET-1 mRNA level was assessed by reverse transcription-polymerase chain reaction. During ischemia the plasma ET-1 levels and big ET-1 levels did not change significantly, while the myocardial ET-1 mRNA level decreased to 57.8%. During reperfusion an increase of the coronary sinus ET-1 and big ET-1 levels was observed (control versus reperfusion, 90 minutes; ET-1, 15.2 +/- 4.18 fmol/mL versus 23.2 +/- 5.23 fmol/mL, P < 0.01; big ET-1, 14.7 +/- 5.9 fmol/mL versus 27.2 +/- 7.1 fmol/mL, P < 0.001). Simultaneously, the ET-1 mRNA level increased by 322% relative to the ischemic and by 214% relative to the baseline level. The decrease of ET-1 mRNA during ischemia may be due to degradation and decreased metabolism in the hypoxic cells locally. The elevation of the ET-1 mRNA level during reperfusion indicates rapid big ET-1 synthesis. This was confirmed by the increases in big ET-1 and ET-1 plasma levels. This latter can be associated with the generation of reperfusion arrhythmias or other complications of acute myocardial infarction.
Keltai
Katalin
K
3rd Department of Medicine, Semmelweis University, Budapest, Hungary. keltaikati@freemail.hu
Vágó
Hajnalka
H
Zsáry
András
A
Karádi
István
I
Kékesi
Violetta
V
Juhász-Nagy
Alexander
A
Merkely
Béla
B
D000818:Animals; D015153:Blotting, Western; D004195:Disease Models, Animal; D004285:Dogs; D019332:Endothelin-1 / Q000235:genetics* / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation; D047468:Immunoprecipitation; D008297:Male; D017202:Myocardial Ischemia / Q000235:genetics* / Q000378:metabolism; D015425:Myocardial Reperfusion; D009206:Myocardium / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
D019332:Endothelin-1; D012333:RNA, Messenger