Insulin resistance is associated with the circulating free fatty acid (FFA) level and intracellular lipid content in muscle and liver. We investigated the effect of 2-wk diet and exercise therapy on total adiposity, circulating FFA, intracellular lipid content in muscle and liver, and peripheral insulin sensitivity. Type 2 diabetic patients were divided into a diet group (n = 7) and a diet plus exercise group (n = 7). We performed a hyperinsulinemic-euglycemic clamp study before and after treatment. Intramyocellular lipid (IMCL) in the tibialis anterior muscle and intrahepatic lipid (IHL) were evaluated by (1)H-magnetic resonance spectroscopy. Fasting FFA were not altered, and total body fat showed a slight, but significant, decrease in both groups after treatment. IMCL was decreased by 19%, and the glucose infusion rate was increased by 57% in the diet plus exercise group, whereas neither IMCL nor glucose infusion rate was significantly altered in the diet group. However, IHL showed a significant decrease in both groups. In summary, we found that 2 wk of diet and exercise decreased IMCL and increased muscle insulin-mediated glucose uptake, whereas diet with or without exercise decreased IHL. These effects were evident despite a small decrease in body fat and were observed independently of fasting FFA levels.
Our results suggest that moderate weight reduction in obese subjects decreased IHL and augmented splanchnic glucose uptake. This mechanism is at least in part involved in improvement of glucose metabolism by moderate weight reduction in obese subjects.
In a retrospective brain magnetic resonance imaging study, we evaluated the prevalence and severity of signal hyperintensities in 30 elderly depressed patients and 30 controls matched for age, sex and cerebrovascular risk factors. A semiquantitative scoring method was used to grade findings in T2-weighted and proton density images. The elderly depressed patients had more extended periventricular hyperintensities, especially in the frontal region (depressed vs. control, 87 vs. 57%, p < 0.05), pons (33 vs. 7%, p < 0.05) as well as hyperintensities in the putamen and globus pallidus (57 vs. 27%, p < 0.05). The third ventricle was more dilated in depressed patients than controls after adjustment for age and cerebrovascular risk factors. The global index for ventricular enlargement was correlated significantly (r = 0.36, p < 0.05) with the severity of the hyperintensity in depressed patients. Our results indicate that these hyperintensities, especially in the frontal region, pons and lenticular nuclei, and the dilatation of the third ventricle play an important role, through the frontal-subcortical circuits, in mood regulation of elderly depressed patients.
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