title: alpha-Tocopherol levels in plasma in new-onset, insulin-dependent diabetes mellitus.
abstract: BACKGROUND: Diabetic complications have been related to increased oxidative stress. Plasma antioxidant levels may be affected by hyperglycemia-induced oxidative stress as well as by insulin therapy. We evaluated the immediate effect of insulin treatment and improved metabolic control on the important antioxidant alpha-tocopherol plasma (vitamin E) levels in new-onset, insulin-dependent diabetes mellitus. METHODS: The study was performed in 15 consecutive patients, aged 20-67 years, with new-onset diabetes mellitus requiring acute insulin treatment. Plasma alpha-tocopherol levels were measured before the start of intensive insulin treatment and monthly for 6 months thereafter. Simultaneously, we studied plasma malondialdehyde (MDA) as a reflection of lipid peroxidation. In addition, comparisons were made to a nondiabetic reference group. RESULTS: Baseline alpha-tocopherol levels did not differ from those in nondiabetic subjects. alpha-Tocopherol decreased significantly, from 33.5+/-12.1 mumol/l before treatment to 28.11+/-6.85 mumol/l (-16%) after 1 month of insulin therapy (p<0.04) to 26.6+/-7.03 mumol/l (-20%) after 3 months of insulin therapy (p<0.02). This trend did not change after adjusting for variations in cholesterol levels. After 6 months, alpha-tocopherol was no longer decreased compared to baseline levels (29.6+/-7.4 mumol/l). MDA concentrations at baseline were significantly higher in the diabetic patients (3.79+/-2.91 mumol/l) than in the nondiabetic subjects (1.57+/-0.21 mumol/l, p=0.006). MDA concentrations decreased significantly following the start of insulin treatment. CONCLUSIONS: Patients with new-onset, insulin-dependent diabetes mellitus have alpha-tocopherol levels that are similar to those in normal subjects. Insulin treatment and/or improved metabolic control cause a significant decrease in alpha-tocopherol levels during the first months.
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, D01.335, PO Box 85500, 3508 GA Utrecht, The Netherlands; Department of Internal Medicine, University Medical Center Utrecht, The Netherlands.
authors.forename: Marian J
authors.initials: MJ
authors.lastname: Muis
authors.forename: Ronald P
authors.initials: RP
authors.lastname: Stolk
authors.forename: Hans M G
authors.initials: HM
authors.lastname: Princen
authors.forename: P S
authors.initials: PS
authors.lastname: Van Dam
authors.forename: L D
authors.initials: LD
authors.lastname: Dikkeschei
authors.forename: Diederick E
authors.initials: DE
authors.lastname: Grobbee
authors.forename: Henk J G
authors.initials: HJ
authors.lastname: Bilo