Normal metabolism of apolipoprotein B100-containing lipoproteins despite qualitative abnormalities in type 1 diabetic men.

AIMS/HYPOTHESIS: Type 1 diabetic subjects are at increased risk of cardiovascular disease and exhibit multiple qualitative abnormalities of apolipoprotein (apo) B100-containing lipoproteins. This stable isotope kinetic experiment was designed to study whether these abnormalities are associated with changes in the synthesis and fractional catabolic rates of VLDL-, IDL- and LDL-apoB100. METHODS: Using a bolus followed by a 16-h constant infusion of 13C-leucine, we performed a kinetic study in eight men with type 1 diabetes treated with a continuous subcutaneous insulin infusion administered by an external pump and in seven healthy men, in the fed state. RESULTS: The mean HbA1c level in the type 1 diabetic patients was 8.00+/-1.48%. Plasma triglyceride, and total, LDL and HDL cholesterol levels were similar in patients and control subjects. VLDL were less triglyceride rich in type 1 diabetic patients than in control subjects (VLDL triglyceride : apoB 6.91+/-0.81 vs 8.29+/-1.24 mmol/g, p=0.05). Conversely, the IDL and LDL of the type 1 diabetic patients contained relatively higher levels of triglycerides (IDL triglycerides : apoB 2.16+/-0.36 vs 1.57+/-0.30 mmol/g, p<0.01; LDL triglycerides : apoB 0.27+/-0.06 vs 0.16+/-0.04 mmol/g, p<0.05). The apoB100 pool size, production and fractional catabolic rates in the two groups of subjects were similar for all lipoprotein fractions. CONCLUSIONS/INTERPRETATION: Despite qualitative abnormalities, especially abnormalities of triglyceride content, the metabolism of apoB100-containing lipoproteins is not altered in type 1 diabetic men with fair glycaemic control with continuous subcutaneous insulin infusion. The high risk of atherosclerosis in these patients cannot be explained by kinetic abnormalities of apoB100-containing lipoproteins.

Intravenous methylprednisolone pulse therapy in the treatment of Graves' ophthalmopathy.

Graves' ophthalmopathy (GO) is a specific immune-mediated disorder, whose treatment is sometimes difficult. In order to investigate the efficacy of intravenous methylprednisolone (MP) pulse therapy in GO, we studied eight patients with GO, followed up for at least 6 months by clinical patient self-assessment, ophthalmological examination and orbital computed tomography (OCT). A 12.5 mg/kg dose of MP was administered intravenously over a 10 hour period, once every month. Three to six MP pulse administrations were performed in each patient. All patients were outpatients. A 0.5 mg/kg/day oral prednisone dose was given to each patient as interpulse therapy. Clinical assessment of MP pulse therapy showed a good response in 87.5% and no response in 12.5% of patients. The treatment was rapidly efficient, mostly on patient self-assessment, soft tissue inflammation, ophthalmoplegia, corneal involvement, visual acuity and extraocular muscle enlargement on OCT. Post-treatment ophthalmic index was significantly improved (6.75 +/- 3.06 vs. 2.5 +/- 1.41: p < 0.05). MP pulse therapy had less effect on proptosis (22.94 +/- 2.32 mm vs. 21.56 +/- 2.22 mm: p < 0.05). No adverse effects were noted with MP pulse therapy. Patients showed no relapse of eye involvement during a mean follow up of 31.8 months (2-77 months). In conclusion, our results suggest that intravenous MP pulse therapy is a good immunosuppressive therapy for GO. Moreover, in comparison with the previous studies, the MP dose used in our present study appears to be optimal with high efficacy. MP pulse therapy represents a safe and efficient treatment in GO, which can easily be performed in outpatients.