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Suppression of rat carotid lesion development by the calcium channel blocker PN 200-110
Abstract:
Balloon catheter damage of the rat carotid artery endothelium results in an extensive and reproducible neointimal lesion composed of smooth muscle cells and connective matrix. The authors have examined two calcium channel blockers, PN 200-110 and PY 108-068, for their ability to inhibit neointimal lesion development in the rat carotid model. When given subcutaneously (1.0 mg/kg day) both compounds produced rapidly acting and long-lasting hypotension, reducing blood pressure 25-29%. At this dose given daily, PN 200-110 reduced lesion cross-sectional area by 44%, compared with only 25% seen by PY 108-068, which suggests that the antiatherosclerotic effect may not be related to lowering of blood pressure. Furthermore, PN 200-110 did not reduce the extent of platelet deposition (compared with controls) occurring at the denuded vessel surface 1 hour or 24 hours after balloon catheterization, which indicates that the inhibition of lesion development may not reflect an antiplatelet mechanism. The observed inhibition by PN 200-110 may relate to mitogen responses of the smooth muscle cell in the vessel wall (migration and proliferation) involved in lesion progression after endothelial damage.
Insights
The calcium channel blocker PN 200-110 effectively inhibited neointimal lesion development in a rat carotid artery model. This antiatherosclerotic effect may stem from inhibiting smooth muscle cell proliferation rather than lowering blood pressure.
Area of Science:
- Vascular Biology
- Pharmacology
- Cardiovascular Research
Background:
- Balloon catheterization of rat carotid arteries induces reproducible neointimal lesions.
- These lesions comprise smooth muscle cells and extracellular matrix, mimicking aspects of atherosclerosis.
Purpose of the Study:
- To evaluate the efficacy of two calcium channel blockers, PN 200-110 and PY 108-068, in preventing neointimal lesion formation.
- To investigate the potential mechanisms underlying the antiatherosclerotic effects, differentiating between blood pressure reduction, antiplatelet activity, and effects on smooth muscle cell proliferation.
Main Methods:
- Rats underwent balloon catheterization of the carotid artery to induce endothelial damage.
- Animals were treated daily with subcutaneous injections of PN 200-110 or PY 108-068 (1.0 mg/kg).
- Blood pressure, neointimal lesion area, and platelet deposition were assessed post-treatment.
Main Results:
- Both PN 200-110 and PY 108-068 caused significant hypotension (25-29%).
- PN 200-110 reduced lesion area by 44%, significantly more than PY 108-068 (25%).
- PN 200-110 did not alter platelet deposition, suggesting its effect is not antiplatelet-mediated.
Conclusions:
- PN 200-110 demonstrates potent inhibition of neointimal lesion development in this model.
- The antiatherosclerotic effect of PN 200-110 is likely independent of its blood pressure-lowering or antiplatelet properties.
- PN 200-110 may exert its beneficial effects by modulating smooth muscle cell migration and proliferation following endothelial injury.