Beneficial effect of hydroxyfasudil, a specific Rho-kinase inhibitor, on ischemia/reperfusion injury in canine coronary microcirculation in vivo.
OBJECTIVE
We examined whether hydroxyfasudil, a specific Rho-kinase inhibitor, exerts cardioprotective effect on coronary ischemia/reperfusion (I/R) injury and, if so, whether nitric oxide (NO) is involved.


BACKGROUND
Recent studies have demonstrated that Rho-kinase is substantially involved in the pathogenesis of cardiovascular diseases; however, it remains to be examined whether it is also involved in ischemia/reperfusion (I/R) injury.


METHODS
Canine subepicardial small arteries (SA, >or=100 microm) and arterioles (A, <100 microm) were observed by a charge-coupled device intravital microscope during I/R. Coronary vascular responses to endothelium-dependent (acetylcholine, intracoronary [IC]) and -independent (papaverine, IC) vasodilators were examined after I/R under the following four conditions: control (n = 7), NO synthase inhibitor alone (N(G)-monomethl-L-arginine [L-NMMA], IC, n = 4), hydroxyfasudil alone (IC, n = 7), and hydroxyfasudil plus L-NMMA (n = 7).


RESULTS
Hydroxyfasudil significantly attenuated serotonin (IC)-induced vasoconstriction of SA (-7 +/- 1% vs. 2 +/- 1%, p < 0.01). Coronary I/R significantly impaired coronary vasodilation to acetylcholine after I/R (SA, p < 0.05; and A, p < 0.01 vs. before I/R) and L-NMMA further reduced the vasodilation, whereas hydroxyfasudil completely preserved the responses. The vasoconstriction by L-NMMA after I/R was significantly improved by hydroxyfasudil in both-sized arteries (both p < 0.01). Expression of endothelial nitric oxide synthase (eNOS) protein in the ischemic endocardium of left anterior descending coronary artery area (as determined by Western blotting) significantly decreased (79 +/- 4%) compared with the nonischemic endocardium of LCX area (100 +/- 7%), which was improved by hydroxyfasudil (105 +/- 6%, p < 0.01). Hydroxyfasudil significantly reduced myocardial infarct size, and hydroxyfasudil with L-NMMA also reduced the infarct size compared with L-NMMA alone.


CONCLUSIONS
Hydroxyfasudil exerts cardioprotective effects on coronary I/R injury in vivo, in which NO-mediated mechanism may be involved through preservation of eNOS expression.
Yada
Toyotaka
T
Department of Medical Engineering and Systems Cardiology, Kawasaki Medical School, Kurashiki, Okayama, Japan. yada@me.kawasaki-m.ac.jp
Shimokawa
Hiroaki
H
Hiramatsu
Osamu
O
Kajita
Tatsuya
T
Shigeto
Fumiyuki
F
Tanaka
Etsuro
E
Shinozaki
Yoshiro
Y
Mori
Hidezo
H
Kiyooka
Takahiko
T
Katsura
Masashi
M
Ohkuma
Seitaro
S
Goto
Masami
M
Ogasawara
Yasuo
Y
Kajiya
Fumihiko
F
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D000818:Animals; D003326:Coronary Circulation / Q000187:drug effects*; D004285:Dogs; D005260:Female; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D008833:Microcirculation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors*; D015427:Reperfusion Injury / Q000188:drug therapy*; D014664:Vasodilation / Q000187:drug effects; D054460:rho-Associated Kinases
D047908:Intracellular Signaling Peptides and Proteins; C431085:hydroxyfasudil; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases