Elevated glucose in vivo and in vitro adversely alters prostaglandin generation in rat aortas and platelets

An imbalance in prostacyclin (PGI₂) and thromboxane (TXA₂) generation from arachidonic acid (AA) may contribute to the marked increase in susceptibility to cardiovascular disease seen in diabetics. Rats made diabetic with streptozocin, and subsequently treated with saline or insulin, yielded aortic rings that synthesized decreasing amounts of PGI₂ and platelets that generated increasing amounts of TXA₂ in proportion to the degree of hyperglycemia. These alterations in AA metabolism were mimicked by incubating aortic rings or platelets from normal rats in buffer containing elevated glucose concentrations. Platelets incubated in elevated glucose displayed shorter times to maximal aggregation and- higher percent maximal aggregation. Incubation of tissue in a buffer made hyperosmotic with mannitol had no effect on PGI₂ or TXA₂ formation, or platelet aggregation. These data suggest that hyperglycemia is involved in the PGI₂/TXA₂ imbalance and platelet abnormalities seen in diabetes, and reinforces the importance of rigid control of blood glucose as an approach to minimizing the incidence of diabetic cardiovascular complications.