Key result
In experimental diabetes, selective COX-2 gene inactivation protected mice against sympathetic denervation and left ventricular dysfunction compared to wild-type mice.
Why the study?
Does COX-2 gene inactivation prevent left ventricular dysfunction and sympathetic denervation in experimental diabetes?
Does COX-2 gene inactivation prevent left ventricular dysfunction and sympathetic denervation in experimental diabetes?
In experimental diabetes, selective COX-2 inactivation protects against sympathetic denervation and LV dysfunction by reducing intramyocardial oxidative stress, inflammation, and myocardial fibrosis.
No immediate clinical implications for COX-2 targeting in diabetes; leaves open translation from mouse models.
Glucose-mediated oxidative stress and the upregulation of cyclooxygenase (COX)-2 pathway activity have been implicated in the pathogenesis of several vascular complications of diabetes including diabetic neuropathy. However, in nondiabetic subjects, the cardiovascular safety of selective COX-2 inhibition is controversial. The aim of this study was to explore the links between hyperglycemia, oxidative stress, activation of the COX-2 pathway, cardiac sympathetic integrity, and the development of left ventricular (LV) dysfunction in experimental diabetes. R wave-to-R wave interval (R-R interval) and parameters of LV function measured by echocardiography using 1% isoflurane, LV sympathetic nerve fiber density, LV collagen content, and markers of myocardial oxidative stress, inflammation, and PG content were assessed after 6 mo in control and diabetic COX-2-deficient (COX-2(-/-)) and littermate, wild-type (COX-2(+/+)) mice. There were no differences in blood glucose, LV echocardiographic measures, collagen content, sympathetic nerve fiber density, and markers of oxidative stress and inflammation between nondiabetic (ND) COX-2(+/+) and COX-2(-/-) mice at baseline and thereafter. After 6 mo, diabetic COX-2(+/+) mice developed significant deteriorations in the R-R interval and signs of LV dysfunction. These were associated with a loss of LV sympathetic nerve fiber density, increased LV collagen content, and a significant increase in myocardial oxidative stress and inflammation compared with those of ND mice. Diabetic COX-2(-/-) mice were protected against all these biochemical, structural, and functional deficits. These data suggest that in experimental diabetes, selective COX-2 inactivation confers protection against sympathetic denervation and LV dysfunction by reducing intramyocardial oxidative stress, inflammation, and myocardial fibrosis.
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Kellogg et al. (2008) studied Experimental diabetes. COX-2 gene inactivation vs. Wild-type (COX-2(+/+)) mice was evaluated on R-R interval, left ventricular function, sympathetic nerve fiber density, collagen content, oxidative stress, and inflammation. In experimental diabetes, selective COX-2 gene inactivation protected mice against sympathetic denervation and left ventricular dysfunction compared to wild-type mice.
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