Hyperinsulinemia does not cause de novo capillary recruitment in rat skeletal muscle.

OBJECTIVE: The effect of insulin on blood flow distribution within muscle microvasculature has been suggested to be important for glucose metabolism. However, the "capillary recruitment" hypothesis is still controversial and relies on studies using indirect contrast-enhanced ultrasound (CEU) methods. METHODS: We studied how hyperinsulinemia effects capillary blood flow in rat extensor digitorum longus (EDL) muscle during euglycemic hyperinsulinemic clamp using intravital video microscopy (IVVM). Additionally, we modeled blood flow and microbubble distribution within the vascular tree under conditions observed during euglycemic hyperinsulinemic clamp experiments. RESULTS: Euglycemic hyperinsulinemia caused an increase in erythrocyte (80 ± 25%, P < .01) and plasma (53 ± 12%, P < .01) flow in rat EDL microvasculature. We found no evidence of de novo capillary recruitment within, or among, capillary networks supplied by different terminal arterioles; however, erythrocyte flow became slightly more homogenous. Our computational model predicts that a decrease in asymmetry at arteriolar bifurcations causes redistribution of microbubble flow among capillaries already perfused with erythrocytes and plasma, resulting in 25% more microbubbles flowing through capillaries. CONCLUSIONS: Our model suggests increase in CEU signal during hyperinsulinemia reflects a redistribution of arteriolar flow and not de novo capillary recruitment. IVVM experiments support this prediction showing increases in erythrocyte and plasma flow and not capillary recruitment.

High prevalence of disordered eating behavior in Danish children and adolescents with type 1 diabetes.

OBJECTIVE: A higher prevalence of disordered eating behavior (DEB) has been demonstrated in children and adolescents with type 1 diabetes (T1D) compared to healthy aged-matched peers. DEB is associated with higher HbA1c levels and increased risk of developing complications to T1D. The aim of this study was to determine the prevalence of DEB in a Danish cohort of children and adolescents with T1D aged 11 to 19 years and to characterize them regarding metabolic control and relevant clinical data. RESEARCH DESIGN AND METHODS: In a cross-sectional study, we determined the prevalence of DEB using the revised Diabetes Eating Problem Survey (DEPS-R) questionnaire. HbA1c and relevant clinical data were obtained at the time they filled in the questionnaire. RESULTS: Hundred and ninety-two children and adolescents (46% girls) aged 11 to 19 years with T1D were included from the pediatric diabetes outpatient clinic. A total of 40 participants (21%) had DEB. The prevalence was higher among girls compared with boys (34.1% vs 8.9%) and those who had DEB were older (16.7 vs 15.0 years, P < .001), had longer duration of T1D (7.5 vs 4.9 years, P < .001), higher BMI Z-scores (1.2 vs 0.3, P < .001), higher HbA1c (72.8 (8.8%) vs 62.0 (7.8%) mmol/mol, P < .001), higher total cholesterol (4.6 mmol/L vs 4.2 mmol/L, P = .0048), and LDL (2.7 vs 2.3, P = .001) compared with those with no signs of DEB. CONCLUSION: As in other countries, the prevalence of DEB is high in Danish adolescents with T1D. Early detection of DEB is essential to prevent short- and long-term complications to T1D.