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Age-dependent increase in xanthine oxidoreductase differs in various heart cell types
1Cardiochemical Laboratory, Thoraxcenter, Erasmus University Rotterdam, The Netherlands.
Circulation Research
|October 1, 1987
Summary
Myocardial xanthine oxidoreductase activity increases significantly with age in rat hearts, correlating with reperfusion injury. This enzyme activity is lower in myocytes than in nonmuscular cells.
Area of Science:
- Biochemistry
- Cardiology
- Cell Biology
Background:
- Myocardial xanthine oxidase contributes to reoxygenation injury via oxygen radicals.
- Ischemia-reperfusion damage in the heart intensifies with age.
- Higher xanthine oxidase levels are expected in adult compared to young hearts.
Purpose of the Study:
- To investigate the age-dependent changes in xanthine oxidoreductase activity in rat hearts.
- To determine the enzyme's localization within cultured rat heart cells.
Main Methods:
- Xanthine oxidase plus dehydrogenase activity was measured in heart homogenates and cultured cardiac cells (myocytes and nonmuscular cells).
- Enzyme activity was quantified across different ages in rats and at various time points in cell cultures.
Main Results:
- Rat heart xanthine oxidoreductase activity increased from 0.5 mU/g (newborn) to 25 mU/g (15 weeks).
- Activity in cultured rat myocytes rose from 4.2 mU/g to 17 mU/g over 4 days.
- Activity in nonmuscular cells showed a more substantial increase, from 10.1 mU/g to 117 mU/g.
Conclusions:
- The age-related rise in cardiac xanthine oxidoreductase activity supports its role in reperfusion injury.
- Myocytes exhibit lower xanthine oxidoreductase activity compared to nonmuscular cells, warranting further investigation into myocyte damage mechanisms.