Direct evidence for increased hydroxyl radicals originating from superoxide in the failing myocardium

Tomomi Ide, Hiroyuki Tsutsui, Shintaro Kinugawa, Nobuhiro Suematsu, Shunji Hayashidani, Kazuhiro Ichikawa, Hideo Utsumi, Youji Machida, Kensuke Egashira, Akira Takeshita

Research output: Contribution to journalArticlepeer-review

356 Citations (Scopus)


Experimental and clinical studies have suggested an increased production of reactive oxygen species (ROS) in the failing myocardium. The present study aimed to obtain direct evidence for increased ROS and to determine the contribution of superoxide anion (·O2-), H2O2, and hydroxy radical (·OH) in failing myocardial tissue. Heart failure was produced in adult mongrel dogs by rapid ventricular pacing at 240 bpm for 4 weeks. To assess the production of ROS directly, freeze-clamped myocardial tissue homogenates were reacted with the nitroxide radical, 4-hydroxy-2,2,6,6,-tetramethyl- piperidine-N-oxyl, and its spin signals were detected by electron spin resonance spectroscopy. The rate of electron spin resonance signal decay, proportional to ·OH level, was significantly increased in heart failure, which was inhibited by the addition of dimethylthiourea (·OH scavenger) into the reaction mixture. Increased ·OH in the failing heart was abolished to the same extent in the presence of desferrioxamine (iron chelator), catalase (H2O2 scavenger), and 4,5-dihydroxy-1,3-benzene disulfonic acid (Tiron; LaMotte) (·O2- scavenger), indicating that ·OH originated from H2O2 and ·O2-. Further, ·O2- produced in normal myocardium in the presence of antimycin A (mitochondrial complex III inhibitor) could reproduce the increase of H2O2 and ·OH seen in the failing tissue. There was a significant positive relation between myocardial ROS level and left ventricular contractile dysfunction. In conclusion, in the failing myocardium, ·OH was produced as a reactive product of ·O2- and H2O2, which might play an important role in left ventricular failure.

Original languageEnglish
Pages (from-to)152-157
Number of pages6
JournalCirculation research
Issue number2
Publication statusPublished - 2000

All Science Journal Classification (ASJC) codes

  • Physiology
  • Cardiology and Cardiovascular Medicine


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