A multiclinic double-blind trial of pyridinolcarbamate and inositol niacinate in ischemic ulcer due to chronic arterial occlusion

Cyclic nucleotides and atherosclerosis: studies in primary culture of human aortic cells

A primary culture of cells derived from uninvolved and atherosclerotic intima of human aorta was used to elucidate the role of cyclic nucleotides in atherogenesis. The cells cultured from fatty streaks and atherosclerotic plaques had a 2- to 8-fold lower cyclic AMP level and a 1.5- to 2-fold higher level of cyclic GMP compared with those of a grossly normal intima. Medial cells cultured from nonlesioned and atherosclerotic aortic segments showed no differences in the cyclic nucleotide concentrations. Reduction of the intracellular cyclic AMP with 2'-deoxyadenosine or a cyclic GMP elevation with its dibutyryl derivative, or liposomes containing cyclic GMP stimulated the uptake of [3H]thymidine and protein synthesis in the cells cultured from unaffected intima. On the contrary, a rise of the intracellular cyclic AMP caused by adenylate cyclase activators, a phosphodiesterase inhibitor, dibutyryl cyclic AMP, and liposomes containing cyclic AMP inhibited cell proliferation and protein synthesis. Elevation of the intracellular cyclic AMP stimulated the hydrolysis of lipids which led to reduction of lipid levels in the cells cultured from atherosclerotic lesions. The results of this study corroborate the existence of a relationship between the alterations of intracellular cyclic nucleotide levels and the metabolic disorders occurring in atherosclerosis.

Anti-proliferative effect of pyridinolcarbamate and of aspirin in the early stages of atherogenesis in swine

When young swine are fed a suitable hyperlipidemic (HL) diet the number of cells in intimal cell masses (ICM) of large and medium-sized arteries begins to increase in number; by 90 days on the diet the cell increase is several-fold compared to no significant increase in cell numbers in ICM of mash-fed controls. The objective of the current study was to see if the cell increase associated with the HL diet could be reduced by pyridinolcarbamate or aspirin. Arteries studied were the abdominal aorta and the coronaries; time on HL diet was 90 days. Both drugs resulted in significant reductions in the increases in cells in ICM associated with the HL diet in both of the arterial beds that were studied. The reduction was most prominent in the abdominal aorta where the increase in ICM cells in the untreated HL diet-fed swine was from an average of 242 +/- 50 cells per cross-section in the mash-fed controls to 1925 +/- 556; in the pyridinolcarbamate-treated swine the increase was only to 641 +/- 214 and in the aspirin-treated group to 770 +/- 146.

Therapeutic effect of ticlopidine, a new inhibitor of platelet aggregation, on chronic arterial occlusive diseases, a double-blind study versus placebo

The clinical efficacy of ticlopidine, a platelet aggregation inhibitor, was evaluated in a double-blind placebo-controlled study on 193 patients with ischemic ulcers due to chronic arterial occlusion. In the group treated with ticlopidine, significantly better efficacy was noted over the placebo group in terms of judgment on overall improvement by doctors in charge as well as by the committee assessing with color slide films. The drug was particularly effective for the treatment of patients with occlusion in the arteries on the distal side and for the ischemic ulcer with relatively small size. In the group with ticlopidine, granulation was significantly improved compared to the placebo group. Those patients who had pain due to arterial occlusion on the distal side were significantly improved by this agent. The mean diameters of ulcers were clearly reduced. Therefore, this agent could possibly be claimed as an effective remedy against the main symptoms of chronic arterial occlusion. The frequencies of side effects and abnormalities in laboratory tests were comparable in the group treated with ticlopidine to those of the group with placebo. It was, therefore, concluded that this agent has an outstanding clinical value as a conservative treatment in chronic arterial occlusion.

Prostaglandins and ischemic heart disease

There is an abundance of information suggesting that prostaglandins are involved in the development and clinical expression of atherosclerosis. Many studies demonstrate a relationship between prostaglandins and the risk factors for peripheral and coronary artery disease. Thus, part of the mechanism by which hyperlipidemia, diabetes mellitus, smoking, hypertension, sex hormones, age, heredity, emotional stress and diet contribute to the development and progression of atherosclerosis may be through an imbalance between thromboxane A2 and prostaglandin I2. Recent studies show a temporal relationship between acute ischemic events (specifically, unstable angina) and a transcardiac increase in thromboxane B2, while others demonstrate a salutary effect of disaggregatory and vasodilatory prostaglandins in such patients. If prostaglandins and thromboxane prove important in ischemic vascular disease, attention will be directed at the correction of their pathologic imbalance. This may be accomplished by dietary manipulation as well as by the development of prostaglandin receptor antagonists or inhibitors of specific prostaglandin pathways.