Calcium channel blocker-induced protection against cardiovascular damage

Comparative effects of azelnidipine and other Ca2+-channel blockers on the induction of inducible nitric oxide synthase in vascular smooth muscle cells

Overproduction of nitric oxide by inducible nitric oxide synthase contributes to the progression of cardiovascular disease. We investigated the effects of azelnidipine and other Ca2+-channel blockers on nitric oxide production by cultured aortic smooth muscle cells isolated from Wistar rats and human umbilical vein endothelial cells (HUVECs), using the Griess reaction and oxyhemoglobin method. Release of lactic dehydrogenase (LDH) was measured to evaluate cell damage, and immunohistochemistry was performed to examine the expression of inducible nitric oxide synthase and nitrotyrosine protein. Azelnidipine and other Ca2+-channel blockers inhibited the release of nitric oxide induced by lipopolysaccharide plus interferon-gamma. Azelnidipine inhibited it most potently among the Ca2+-channel blockers tested (azelnidipine, amlodipine, nifedipine, diltiazem, verapamil, and nicardipine) at a concentration of 10 microM. Longer stimulation with these agents induced the expression of inducible nitric oxide synthase and nitrotyrosine, with an increase of lactic dehydrogenase release, whereas azelnidipine suppressed these changes. In human umbilical vein endothelial cells, azelnidipine enhanced basal nitric oxide production by endothelial nitric oxide synthase. In conclusion, azelnidipine potently inhibited the induction of inducible nitric oxide synthase and then nitric oxide production in vascular smooth muscle cells, while enhancing constitutive nitric oxide production by endothelial cells. Azelnidipine may inhibit nitrotyrosine expression and cell damage caused by overproduction of nitric oxide, suggesting a mechanism for its cardiovascular protective effect.

A formidable challenge: the diagnosis and treatment of viral myocarditis in children

It is generally well accepted that one third of patients with viral myocarditis experience a complete recovery of normal cardiac function, one third improve clinically but show residual cardiac dysfunction, and one third experience chronic heart failure and die or require heart transplantation. It is hoped that a better understanding of the underlying cause and pathogenesis of this disease will increase the number of patients who experience a complete recovery. New advances in both the diagnosis and treatment of viral myocarditis continue to enter clinical practice at a rapid pace, and it is likely that a genomic approach to the diagnostic evaluation and treatment of this disease will become possible in the near future. Viral myocarditis, however, will remain a significant diagnosticand therapeutic challenge to both physicians and scientists alike.