Association of Postprandial Hyperglycemia with in Vitro LDL Oxidation in Non-Smoking Patients with Type 1 Diabetes – a Cross-Sectional Study

Abstract

BACKGROUND: Cardiovascular disease is the main cause of death in patients with type 1 diabetes. Since oxidized low density lipoprotein (LDL) is considered to be a critical factor in the atherosclerotic process, the aim of our study was to assess the influence of different parameters of glycemic control on susceptibility to oxidative stress from low density lipoprotein (LDL) in patients with type 1 diabetes without microvascular or macrovascular complications. METHODS: Forty patients and 33 non-diabetic individuals matched for gender, age and body mass index (BMI) were evaluated. The two groups underwent determination of lipid profile, fasting and postprandial glucose control and measurement of glycated hemoglobin (HbA1c). Spectrophotometric analysis of the LDL oxidation index was performed before and 1, 3, 6 and 24 h after the addition of copper sulfate to purified LDL fractions. RESULTS: The oxidation coefficient for LDL presented similar basal values in the two groups; however, at 3 h, LDL showed a higher degree of oxidation in patients with type 1 diabetes. Correlations with the metabolic control variables were significant only for postprandial glycemia. Stepwise multiple regression showed that postprandial glycemia and sex were the significant independent variables. CONCLUSION: LDL from patients with type 1 diabetes showed high susceptibility to oxidative stress and this susceptibility was markedly related to the postprandial glucose levels. The influence of our findings on the development of chronic complications in patients with type 1 diabetes must be addressed in prospective studies.

Contagem de carboidratos, estado nutricional e perfil metabólico em adolescentes com diabetes mellitus tipo 1

“…A hiperglicemia crônica propicia maior oxidação de partículas de LDL-c, que se acumulam em partículas densas mais aterogênicas. 41 Foi documentado por Queiroz et al 42 que variáveis inseridas no hábito de vida de crianças e adolescentes, como o consumo da merenda oferecida na escola ou o lanche adquirido nesse estabelecimento, tendem a afetar negativamente o controle glicêmico. Ao aprender sobre contagem de carboidratos, o paciente deve compreender que, apesar de diferentes alimentos conterem quantidades equivalentes de carboidratos, isso não significa que eles são igualmente saudáveis.…”

Progression to microalbuminuria in patients with type 1 diabetes: a seven-year prospective study

“…Patients with T1D can be more susceptible to LDL oxidation in vitro [33] and have higher levels of acute-phase proteins compared to non-diabetic subjects [34]. …”

The Protective Effects of Taurine against Early Renal Injury in STZ-Induced Diabetic Rats, Correlated with Inhibition of Renal LOX-1-Mediated ICAM-1 Expression

“…[22] A major risk factor of atherosclerosis, diabetes exerts the atherogenic actions mainly due to the high susceptibility of LDL to oxidative modification in diabetes, and this susceptibility is related to oxidative stress commonly present in diabetes. [23] As a major receptor of oxLDL, endothelial LOX-1 supports the adhesion of monocytes and is upregulated by glycoxidative modifications of lipoproteins in the aortic endothelium of diabetic rats, supporting an important role of LOX-1 in diabetic vasculopathy. [24] LOX-1 induced the activation of the transcription factor NF-k B, which was considered to be one of the major factors involved in ICAM-1 transcription, [6] and such cascade reactions were also present in the renal injury of diabetes.…”