Intracellular metabolism in biopsies from the aorta in patients undergoing coronary bypass surgery

Abnormal glucose and lipid metabolism in striated muscles and arterial wall has been demonstrated in 3 species: the pig, the dog, and human Type 2 diabetic patients, sharing the common feature of peripheral hyperinsulinaemia. In this study eighteen consecutive patients undergoing coronary bypass surgery and eight control patients were examined. Prior to surgery an oral glucose tolerance test showed that eleven out of eighteen patients had impaired glucose tolerance and significantly elevated fasting immune reactive insulin (IRI) and C-peptide concentrations. There was a statistically significant correlation between the 2 hour blood glucose value and the fasting plasma insulin level (R = 0.55, p less than 0.05). During the operation, aortic and muscle biopsies were taken. The eighteen patients undergoing coronary bypass surgery showed disturbances in glucose metabolism, i.e. decreased activity of glycolytic enzymes (hexokinase 0.30 +/- 0.06 versus 0.40 +/- 0.06 U/g, p less than 0.001, and phosphofructokinase 0.48 +/- 0.09 versus 0.61 +/- 0.07 U/g, p less than 0.01). Malic enzyme activity was increased in all patients (0.17 +/- 0.03 versus 0.06 +/- 0.02 U/g, p less than 0.001). Glucose-6-phosphate dehydrogenase was increased in the eleven patients with impaired glucose tolerance (0.55 +/- 0.10 versus 0.30 +/- 0.07, p less than 0.01) parallel to a significant increase in triglyceride content in the aortic wall (16.1 +/- 4.8 versus 3.7 +/- 3.2 mumol/g, p less than 0.01) as well as in the striated muscles (374 +/- 44 versus 48 +/- 6 mumol/g, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)