Gene expression of antioxidative enzymes in the human heart: increased expression of catalase in the end-stage...

Area of Science:

• Cardiology
• Molecular Biology
• Biochemistry

Background:

• Oxidative stress is implicated in heart failure pathogenesis.
• Gene expression of reactive oxygen metabolite-metabolizing enzymes in the human heart is not well understood.

Purpose of the Study:

• To investigate the gene expression of key antioxidant enzymes in human end-stage heart failure.
• To determine if oxidative stress leads to specific changes in antioxidant enzyme expression.

Main Methods:

• Analyzed mRNA and protein levels of MnSOD, CuZnSOD, GPX, and catalase in myocardial tissue from nonfailing and failing human hearts (dilated and ischemic cardiomyopathy).
• Utilized Northern blot, Western blot, and ELISA techniques.
• Assessed enzyme activities for MnSOD, CuZnSOD, GPX, and catalase.

Main Results:

• Catalase mRNA and protein levels were significantly upregulated in both dilated cardiomyopathy (DCM) and ischemic cardiomyopathy (ICM) hearts compared to controls.
• Increased catalase enzyme activity was observed in failing hearts, correlating with elevated mRNA and protein levels.
• mRNA and protein levels, as well as enzyme activities, of MnSOD, CuZnSOD, and GPX were not significantly different between failing and nonfailing hearts.

Conclusions:

• Human end-stage heart failure exhibits specific upregulation of catalase gene expression.
• This catalase upregulation may serve as a compensatory mechanism against increased oxidative stress.
• Gene expression of SOD and GPX remains unaffected in failing human hearts.