Comparison of continuous long-term heparin and oral anticoagulant therapy in patients with severe angina pectoris

Glucosamine may retard atherogenesis by promoting endothelial production of heparan sulfate proteoglycans

Heparan sulfate proteoglycans produced by vascular endothelium may function physiologically to restrain the migration, multiplication, and phenotypic transition of vascular smooth-muscle cells, and to maintain an anticoagulant luminal surface by bonding and activating antithrombin III. Thus, ample production of heparan sulfate proteoglycans may act to prevent atherosclerosis and its thrombotic complications. The ability of exogenous heparin to stimulate synthesis of heparan sulfate proteoglycans by vascular endothelium may be largely responsible for the positive outcomes of most controlled evaluations of low-dose heparin as a long-term therapy for coronary disease. Glucosamine, a biosynthetic precursor of mucopolysaccharides, can substantially enhance mucopolysaccharide production when added to cultured fibroblasts or chondrocytes; the clinical utility of oral glucosamine in osteoarthritis may reflect increased synthesis of cartilage proteoglycans. It is reasonable to speculate that exogenous glucosamine will likewise enhance heparan sulfate proteoglycans production by vascular endothelial cells, and, when administered orally in regimens comparable to those effective in osteoarthritis, will thereby act to retard atherogenesis.

Heparin as a therapy for atherosclerosis: preliminary observations on the intrapulmonary administration of low-dose heparin in the morning versus evening gauged by its effect on blood variables

Reports on clinical trials with subcutaneous and intrapulmonary administration of low-dose heparin suggest that it may be an attractive therapeutic modality for the treatment of coronary artery disease because of unprecedented reduction in mortality of treated subjects. As a preliminary to a clinical trial with low-dose intrapulmonary heparin, a pilot study was conducted on three subjects. It compares overall circadian responses of 37 blood variables following intrapulmonary administration of heparin (10,500-18,800 U) in the morning (0800 h) and in the evening (2000 h). After each of these times, blood samples, mostly at 3 h intervals for the ensuing 27 h, were analyzed for heparin, APTT, TT, functional fibrinogen, CBC, enzymes, lipids, electrolytes, and hormones. Each time series was analyzed for circadian rhythm by the least-squares fit of a 24 h cosine and circadian mesors were compared by the Bingham test of rhythm parameters. Following heparin in the evening, but not in the morning, a statistically significant increase in circulating heparin levels, as well as directional increases in APTT and TT and decreases in fibrinogen, were observed in all three subjects. Same direction changes in several other variables were also observed. It is concluded that inhalation of heparin in low-dose levels results in variable circadian effects on blood parameters measured, ranging from no changes in their levels to minimal within normal range changes, and that these effects are dependent upon the timing of dose administration. It is suggested that the timed self-administration of low-dose heparin by inhalation be seriously considered for long-term clinical trials in the treatment and prevention of atherosclerosis.

Heparin and atherosclerosis. A review of old and recent findings

This article reviews the experimental and clinical evidence regarding heparin therapy in the prophylaxis of coronary heart disease. The actions of heparin take place at the vascular endothelium where injected heparin concentrates, and within the bloodstream. At the endothelium heparin acts to prevent endothelial injury, prevent thrombin generation, prevent platelet adhesion to endothelium, and to decrease uptake of serum lipoproteins. Within the bloodstream heparin increases lipoprotein lipase activity and reduces the concentration of atherogenic very low-density lipoproteins. The reduction in lipemia enhances oxygen transfer from blood to the tissues, and decreases thrombin or ADP-induced platelet aggregation. Heparin increases the concentration of high-density lipoproteins. It decreases hypercoagulability and inhibits overactivation of serum complement. Heparin reduced atherosclerosis in most studies in cholesterol-fed animals. In human subjects who had a myocardial infarct at least one year before the onset of treatment, long-term intermittent heparin therapy significantly decreased cardiovascular deaths as compared to control groups.