OBJECTIVEAging increases the risk of developing impaired glucose tolerance (IGT) and type 2 diabetes. It has been proposed that increased reactive oxygen species (ROS) generation by dysfunctional mitochondria could play a role in the pathogenesis of these metabolic abnormalities. We examined whether aging per se (in subjects with normal glucose tolerance [NGT]) impairs mitochondrial function and how this relates to ROS generation, whether older subjects with IGT have a further worsening of mitochondrial function (lower ATP production and elevated ROS generation), and whether exercise reverses age-related changes in mitochondrial function.RESEARCH DESIGN AND METHODSMitochondrial ATP and ROS production were measured in muscle from younger individuals with NGT, older individuals with NGT, and older individuals with IGT. Measurements were performed before and after 16 weeks of aerobic exercise.RESULTSATP synthesis was lower in older subjects with NGT and older subjects with IGT versus younger subjects. Notably, mitochondria from older subjects (with NGT and IGT) displayed reduced ROS production versus the younger group. ATP and ROS production were similar between older groups. Exercise increased ATP synthesis in the three groups. Mitochondrial ROS production also increased after training. Proteomic analysis revealed downregulation of several electron transport chain proteins with aging, and this was reversed by exercise.CONCLUSIONSOld mitochondria from subjects with NGT and IGT display mitochondrial dysfunction as manifested by reduced ATP production but not with respect to increased ROS production. When adjusted to age, the development of IGT in elderly individuals does not involve changes in mitochondrial ATP and ROS production. Lastly, exercise reverses the mitochondrial phenotype (proteome and function) of old mitochondria.

Aging is associated with alterations in glucose metabolism and sarcopenia that jointly contribute to a higher risk of developing type 2 diabetes. Because aging is considered as a state of low-grade inflammation, in this study we examined whether older, healthy (lean, community-dwelling) participants have altered signaling flux through toll-like receptor 4 (TLR4), a key mediator of innate and adaptive immune responses. We also examined whether a 4-month aerobic exercise program would have an anti-inflammatory effect by reducing TLR4 expression and signaling. At baseline, muscle TLR4, nuclear factor κB p50 and nuclear factor κB p65 protein content, and c-Jun N-terminal kinase phosphorylation were significantly elevated in older versus young participants. The plasma concentration of the TLR4 agonist lipopolysaccharide and its binding protein also were significantly elevated in older participants, indicative of metabolic endotoxemia, which is a recently described phenomenon of increased plasma endotoxin level in metabolic disease. These alterations in older participants were accompanied by decreased insulin sensitivity, quadriceps muscle volume, and muscle strength. The exercise training program increased insulin sensitivity, without affecting quadriceps muscle volume or strength. Muscle TLR4, nuclear factor κB, and c-Jun N-terminal kinase, and plasma lipopolysaccharide and lipopolysaccharide binding protein were not changed by exercise. In conclusion, insulin resistance and sarcopenia of aging are associated with increased TLR4 expression/signaling, which may be secondary to metabolic endotoxemia.

IntroductionThe purpose of this study was to compare and validate the use of SenseWear Armband (SWA) placed on the arm (SWA ARM) and on the back (SWA BACK) in healthy humans during resting and a cycle-ergometer exercise and to evaluate the SWA to estimate Resting Energy Expenditure (REE) and Total Energy Expenditure (TEE) in healthy baboons.MethodsWe studied 26 (15F/11M) human subjects wearing SWA in two different anatomical sites (arm and back) during resting and a cycle-ergometer test and directly compared these results with indirect calorimetry evaluation (IC), performed at the same time. We then inserted the SWA in a metabolic jacket for baboons and evaluated the TEE and REE in free living condition for 6 days in 21 (8F/13M) non-human primates.ResultsIn humans we found a good correlation between SWA place on the ARM and on the BACK with IC during the resting experiment (1.1±0.3 SWAs, 1±0.2 IC kcal/min) and a slight underestimation in the SWAs data compared with IC during the cycle-ergometer exercise (5±1.9 SWA ARM, 4.5±1.5 SWA BACK and 5.4±2.1 IC kcal/min). In the non-human primate (baboons) experiment SWA estimated a TEE of 0.54±0.009 kcal/min during free living and a REE of 0.82±0.06 kcal/min.ConclusionSWA, an extremely simple and inexpensive apparatus, provides quite accurate measurements of energy expenditure in humans and in baboons. Energy expenditure data obtained with SWA are highly correlated with the data obtained with “gold standard”, IC, in humans.

This study aimed to investigate the clinical characteristics, glycemic control, and microvascular complications compared between young-onset type 1 (T1DM) and type 2 diabetes (T2DM) patients at Siriraj Hospital. Patients and Methods: We collected demographic, clinical, glycemic control, and microvascular complication data of young-onset (onset <30 years of age) T1DM and T2DM patients at our center using February 2019-December 2020 data from the Thai Type 1 Diabetes and Diabetes diagnosed Age before 30 years Registry, Care and Network (T1DDAR CN). Results: Of 396 patients, 76% had T1DM and 24% had T2DM. At diagnosis, T1DM were significantly younger (9.7±5.4 vs 16.9±6.4 years, p<0.001), had a lower body mass index (17.2±4.1 vs 30.8±7.9 kg/m 2 , p<0.001), higher prevalence of diabetic ketoacidosis (DKA) (66.1% vs 13.7%, p<0.001), and higher HbA 1c level (12.8±2.6% vs 10.9±3.1%, p=0.002) compared to T2DM. Regarding glycemic control, the mean HbA 1c at registry enrollment did not differ between groups (T1DM 8.3±1.8% vs T2DM 8.1±2.2%, p=0.303), but T1DM achieved HbA 1c <7% significantly less than T2DM (19.3% vs 47.8%, p<0.001). T1DM showed deterioration of glycemic control during 10-20 years of age, and gradually improved during 20-30 years of age, whereas patients with T2DM showed progressive worsening of glycemic control over time. Concerning microvascular complications, the prevalence of diabetic retinopathy (10.6% vs 9%, p=0.92) and diabetic neuropathy (3.4% vs 5.5%, p=0.514) between T1DM and T2DM was not significantly different. However, T2DM had a significantly higher prevalence of diabetic nephropathy (T1DM 10.1% vs T2DM 40.2%, p<0.001) that developed within a significantly shorter duration of diabetes (T1DM 11.0±6.8 vs T2DM 4.3±5.1 years, p<0.001) compared to T1DM. Conclusion: T1DM had a significantly high prevalence of DKA at presentation, and most T1DM did not achieve the glycemic target, especially during adolescence. T2DM had a significantly higher prevalence of diabetic nephropathy that developed within a shorter duration of diabetes compared to T1DM.