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Thromboxane biosynthesis in platelets of diabetic and coronary artery diseased patients
Insights
Platelets from diabetic patients, with or without coronary artery disease (CAD), produce more thromboxane A2 (TXA2). This increased TXA2 synthesis suggests heightened platelet aggregation sensitivity in these individuals.
Area of Science:
- Cardiovascular Medicine
- Endocrinology
- Hematology
Background:
- Diabetic patients with coronary artery disease (CAD) exhibit elevated thromboxane A2 (TXA2) production.
- Platelet hyperactivity is a known concern in diabetes and cardiovascular conditions.
Purpose of the Study:
- To investigate TXA2 biosynthesis in platelets of diabetic patients without exogenous substrate.
- To compare TXA2 production in diabetic patients without CAD versus normal subjects.
- To compare platelet TXA2 biosynthesis in diabetic patients with CAD versus non-diabetic patients with CAD.
Main Methods:
- Radioimmunoassay (RIA) was used to measure TXB2, the stable metabolite of TXA2.
- Platelet aggregation was stimulated using both endogenous and exogenous substrates.
- Subjects included diabetic patients (with/without complications), CAD patients (with/without diabetes), and healthy controls.
Main Results:
- All studied patient groups showed higher TXA2 synthesis compared to normal subjects.
- Diabetic patients had higher plasma triglyceride levels.
- Platelet phospholipid fatty acid distributions were similar across all groups.
Conclusions:
- Platelets from diabetic patients, with or without CAD, demonstrate increased TXA2 synthesis.
- Elevated TXA2 may contribute to increased platelet aggregation sensitivity in diabetic and CAD patients.
- An enhanced thromboxane synthetase system is a potential underlying mechanism.
Abstract:
We have shown that platelets of diabetic patients (D) with coronary artery disease (CAD) produce more thromboxane A2 (TXA2) compared to normal subjects (N), when induced to aggregate with arachidonic acid. The purpose of this investigation was to determine: 1) whether TXA2 biosynthesis in platelets of D without exogenous substrate is increased, 2) whether platelets of D without CAD produce more TXA2 than N and 3) to compare platelet TXA2 biosynthesis in D with those angiographically diagnosed as having CAD but without D. TXB2 (stable metabolite of TXA2) was measured by RIA in platelets of 100 volunteer subjects: 24 D without other clinical complications, 10 D with retinopathy or nephropathy, 7 D with CAD, 30 CAD without D and 11 had D and hypertension. Eighteen subjects had no D, CAD or hypertension. TXA2 synthesis in platelets, stimulated to aggregate with both endogenous and exogenous substrate was higher in all patient classes studied as compared to normal subjects. Plasma triglyceride concentration was higher in diabetics as compared to controls while total cholesterol as well as platelet phospholipid fatty acid distributions were similar in all groups of subjects indicating a similar substrate concentration for TXA2 biosynthesis. It is concluded that platelets of D and CAD with or without D have greater sensitivity to aggregation which might be due to the increased thromboxane synthetase system at one or more sites.