Oxidative Stress after a Carbohydrate Meal Contributes to the Deterioration of Diastolic Cardiac Function in Nonhypertensive Insulin-treated Patients with Moderately Well Controlled Type 2 Diabetes

Abstract

The prevalence and prognostic importance of diastolic dysfunction in type 2 diabetes has only recently been appreciated. We tested the hypothesis that in insulin treated type 2 diabetes (D), carbohydrate consumption induces oxidative stress resulting in further impairment of diastolic function beyond structural myocardial stiffness. The effects of a pure carbohydrate breakfast (48 g) on oxidative stress and cardiac function were studied in the fasting and postmeal states in subjects without hypertension or overt cardiac disease (moderately well controlled D, n=21 and controls without D, n=20). Studied variables included systolic and early diastolic (E') myocardial velocities, traditional metabolic and hemodynamic parameters, serum nitrotyrosine, and sVCAM-1. In D compared to control subjects, the postmeal increase (∆) in glucose (1.44±2.78 vs. 0.11±0.72 mmol/l, p=0.04) and ∆nitrotyrosine (0.34±0.37 vs. -0.23±0.47 nM/l, p<0.001) were significantly higher. sVCAM-1 was higher in fasting and postmeal (p=0.02). E' was significantly lower in postmeal (7.3±1.3 vs. 9.6±1.3 cm/s, p<0.001) and fasting (p<0.001) whereas the rate pressure product was significantly higher (9 420±1 118 vs. 7 705±1 871 mm Hg/min, p<0.001). Multivariable regression models of the pooled data demonstrated that independent predictors for postmeal E' were ∆nitrotyrosine and septal thickness (R² 0.466) and for fasting E' age, ∆nitrotyrosine, and septal thickness (R² 0.400). In insulin requiring type 2 diabetes, carbohydrate consumption may induce oxidative stress that is associated with worsening diastolic function, indicating that this metabolic factor is an important determinant of diastolic dysfunction in the diabetic heart beyond the increase in structural myocardial stiffness.

Fast food increases postprandial cardiac workload in type 2 diabetes independent of pre-exercise: A pilot study

“…The observed postprandial increase in diastolic workload in both type 2 diabetes and healthy overweight individuals is novel. Our data contrast the few previous studies that investigated the effects of lipid infusions or a carbohydrate rich meal on cardiac function [ 9 , 10 ]. Further study is needed to determine whether this is a result of the “combined meal” used here.…”

“…Although few studies have investigated the acute effects of fast food on cardiac function, it is observed that food-induced elevation of circulating glucose and oxidative stress reduce diastolic function in insulin-treated type 2 diabetes patients [ 9 ], and that acute elevations in circulating triglycerides yield compensatory increases in systolic function of the left ventricle in healthy individuals [ 10 ].…”

Plasma total oxidant and antioxidant status after oral glucose tolerance and mixed meal tests in patients with polycystic ovary syndrome

“…In another study performed with the same team [22], it was revealed that maltodextrin and dextrose given at the dose of 2.25 gr/kg had no effects on TAG, malondialdehyde, hydrogen peroxide, nitrate/nitrite and trolox-equalant antioxidant capacity measured at baseline, 1st, 2nd, 4th and 6th hours. However, in another study where the effects of 48 gr of glucose loading along with subcutaneous insulin on OS and cardiac functions were investigated in 21 diabetic patients and 20 controls nearly at the age of 60 years, Bibra et al [23] reported that when OS was measured with nitrothyrosine, OS levels were similar in diabetic patients to those found in controls, but nitrotyrosine levels became increased after loading glucose to patients with DM. In the same study, nitrotyrosine levels were shown to increase from 3.6 to 3.8 nMol/l in diabetics while decreasing from 3.4 to 3 nMol/l in controls, and we considered that the difference could arise from the decrease in controls rather than the increase seen in diabetics.…”

“…The reduction in OS by antioxidants may display favor effects on the development of CVDs [19]. In the literature, many studies with controversial results report that macronutrients, such as carbohydrates, triglyceride and protein have a developmental effect on OS in different populations of patients [20][21][22][23][24][25][26]. Oral glucose tolerance test is frequently used in daily practice for detecting DM or gestational DM.…”

Selenium Supplementation Affects Insulin Resistance and Serum hs-CRP in Patients with Type 2 Diabetes and Coronary Heart Disease

“…Endocrine Care overproduction of free radicals and reactive oxygen species (ROS), which in turn play an important role in precipitating diabetic vascular disease [6][7][8].…”