Related Experiment Videos
Urate production by human heart
T Huizer1, J W de Jong, J A Nelson
1Thoraxcenter, Erasmus University Rotterdam, The Netherlands.
Insights
Xanthine oxidoreductase activity in the human heart is debated. This study suggests its presence, showing increased urate production during myocardial ischemia in patients with heart disease.
Area of Science:
- Cardiology
- Biochemistry
Background:
- The presence and role of xanthine oxidoreductase (XOR) in the human heart remain uncertain, with reported levels varying significantly.
- XOR catalyzes the production of urate, a key indicator of its activity.
Purpose of the Study:
- To investigate the presence and activity of xanthine oxidoreductase in the human heart.
- To determine if XOR contributes to urate production during transient myocardial ischemia.
Main Methods:
- Studied arterial-venous urate differences across the heart in patients undergoing cardiac catheterization and percutaneous transluminal coronary angioplasty.
- Measured plasma urate and coronary sinus hypoxanthine levels before and after angioplasty, especially during induced ischemia.
Main Results:
- A significant increase in plasma urate levels was observed in the great cardiac vein compared to arterial levels before angioplasty (26 +/- 10 nmol/ml, P = 0.028).
- Urate production peaked immediately after coronary occlusions (23 +/- 8 nmol/ml, P = 0.018), coinciding with elevated hypoxanthine levels in the coronary sinus.
Conclusions:
- Xanthine oxidoreductase is likely present in the human heart, particularly in patients with ischemic heart disease.
- The enzyme appears to be responsible for increased urate production during episodes of transient myocardial ischemia.
Abstract:
Xanthine oxidoreductase has been demonstrated in the heart of various species. However, its presence in human heart is still debated. In the literature, high to undetectable levels have been reported. We studied the arterial-venous urate difference across the heart of patients undergoing both routine cardiac catheterization and percutaneous transluminal coronary angioplasty. Urate is the end product of the reaction catalysed by xanthine oxidoreductase. In 10 patients, studied before angioplasty, the plasma urate level in the great cardiac vein exceeded the arterial one by 26 +/- 10 nmol/ml (P = 0.028). In a further 13 patients, urate production was maximal immediately after the last of four consecutive occlusions (23 +/- 8 nmol/ml, P = 0.018) and concomitant with increased coronary sinus hypoxanthine levels. We conclude that xanthine oxidoreductase is probably present in the heart of patients, suffering from ischemic heart disease, and responsible for the increase in urate production during transient myocardial ischemia.