Rosa Ferreira dos Santos

Differential regulation of PGC-1α expression in rat liver and skeletal muscle in response to voluntary running

BackgroundThe beneficial actions of exercise training on lipid, glucose and energy metabolism and insulin sensitivity appear to be in part mediated by PGC-1α. Previous studies have shown that spontaneously exercised rats show at rest enhanced responsiveness to exogenous insulin, lower plasma insulin levels and increased skeletal muscle insulin sensitivity. This study was initiated to examine the functional interaction between exercise-induced modulation of skeletal muscle and liver PGC-1α protein expression, whole body insulin sensitivity, and circulating FFA levels as a measure of whole body fatty acid (lipid) metabolism.MethodsTwo groups of male Wistar rats (2 Mo of age, 188.82 ± 2.77 g BW) were used in this study. One group consisted of control rats placed in standard laboratory cages. Exercising rats were housed individually in cages equipped with running wheels and allowed to run at their own pace for 5 weeks. At the end of exercise training, insulin sensitivity was evaluated by comparing steady-state plasma glucose (SSPG) concentrations at constant plasma insulin levels attained during the continuous infusion of glucose and insulin to each experimental group. Subsequently, soleus and plantaris muscle and liver samples were collected and quantified for PGC-1α protein expression by Western blotting. Collected blood samples were analyzed for glucose, insulin and FFA concentrations.ResultsRats housed in the exercise wheel cages demonstrated almost linear increases in running activity with advancing time reaching to maximum value around 4 weeks. On an average, the rats ran a mean (Mean ± SE) of 4.102 ± 0.747 km/day and consumed significantly more food as compared to sedentary controls (P < 0.001) in order to meet their increased caloric requirement. Mean plasma insulin (P < 0.001) and FFA (P < 0.006) concentrations were lower in the exercise-trained rats as compared to sedentary controls. Mean steady state plasma insulin (SSPI) and glucose (SSPG) concentrations were not significantly different in sedentary control rats as compared to exercise-trained animals. Plantaris PGC-1α protein expression increased significantly from a 1.11 ± 0.12 in the sedentary rats to 1.74 ± 0.09 in exercising rats (P < 0.001). However, exercise had no effect on PGC-1α protein content in either soleus muscle or liver tissue. These results indicate that exercise training selectively up regulates the PGC-1α protein expression in high-oxidative fast skeletal muscle type such as plantaris muscle.ConclusionThese data suggest that PGC-1α most likely plays a restricted role in exercise-mediated improvements in insulin resistance (sensitivity) and lowering of circulating FFA levels.

Cardiovascular, metabolic and hormonal responses to the progressive exercise performed to exhaustion in patients with type 2 diabetes treated with metformin or glyburide.

Objectives:  To evaluate the effects of Metformin and Glyburide on cardiovascular, metabolic and hormonal parameters during progressive exercise performed to exhaustion in the post‐prandial state in women with type 2 diabetes (T2DM).

Metformin, but not glimepiride, improves carotid artery diameter and blood flow in patients with type 2 diabetes mellitus

OBJECTIVE: To compare the effects of glimepiride and metformin on vascular reactivity, hemostatic factors and glucose and lipid profiles in patients with type 2 diabetes. METHODS: A prospective study was performed in 16 uncontrolled patients with diabetes previously treated with dietary intervention. The participants were randomized into metformin or glimepiride therapy groups. After four months, the patients were crossed over with no washout period to the alternative treatment for an additional four-month period on similar dosage schedules. The following variables were assessed before and after four months of each treatment: 1) fasting glycemia, insulin, catecholamines, lipid profiles and HbA1 levels; 2) t-PA and PAI-1 (antigen and activity), platelet aggregation and fibrinogen and plasminogen levels; and 3) the flow indices of the carotid and brachial arteries. In addition, at the end of each period, a 12-hour metabolic profile was obtained after fasting and every 2 hours thereafter. RESULTS: Both therapies resulted in similar decreases in fasting glucose, triglyceride and norepinephrine levels, and they increased the fibrinolytic factor plasminogen but decreased t-PA activity. Metformin caused lower insulin and pro-insulin levels and higher glucagon levels and increased systolic carotid diameter and blood flow. Neither metformin nor glimepiride affected endothelial-dependent or endothelial-independent vasodilation of the brachial artery. CONCLUSIONS: Glimepiride and metformin were effective in improving glucose and lipid profiles and norepinephrine levels. Metformin afforded more protection against macrovascular diabetes complications, increased systolic carotid artery diameter and total and systolic blood flow, and decreased insulin levels. As both therapies increased plasminogen levels but reduced t-PA activity, a coagulation process was likely still ongoing.

The effects of metformin and glibenclamide on glucose metabolism, counter-regulatory hormones and cardiovascular responses in women with Type 2 diabetes during exercise of moderate intensity.

Aims  To compare the effects of metformin and glibenclamide on cardiovascular, metabolic and hormonal parameters during exercise of moderate intensity performed in the postprandial state, in women with Type 2 diabetes.

Erythrocyte insulin receptor tyrosine kinase activity is increased in glyburide-treated patients with type 2 diabetes in good glycaemic control

Aim: The goal of this study was to test the hypothesis that insulin receptor tyrosine kinase activity of isolated erythrocytes would be greater in glyburide‐treated patients with type 2 diabetes in good glycaemic control (n = 13) than in untreated patients (n = 12) with significant fasting hyperglycaemia.

CD226 rs763361 Is Associated with the Susceptibility to Type 1 Diabetes and Greater Frequency of GAD65 Autoantibody in a Brazilian Cohort

CD226 rs763361 variant increases susceptibility to type 1 diabetes (T1D) in Caucasians. There is no data about CD226 variants in the very heterogeneous Brazilian population bearing a wide degree of admixture. We investigated its association with T1D susceptibility, clinical phenotypes, and autoimmune manifestations (islet and extrapancreatic autoantibodies). Casuistry. 532 T1D patients and 594 controls in a case-control study. Initially, CD226 coding regions and boundaries were sequenced in a subset of 106 T1D patients and 102 controls. In a second step, two CD226 variants, rs763361 (exon 7) and rs727088 (3′ UTR region), involved with CD226 regulation, were genotyped in the entire cohort. C-peptide and autoantibody levels were determined. No new polymorphic variant was found. The variants rs763361 and rs727088 were in strong linkage disequilibrium. The TT genotype of rs763361 was associated with TID risk (OR = 1.503;  95%  CI = 1.135–1.991; P = 0.0044), mainly in females (P = 0.0012), greater frequency of anti-GAD autoantibody (31.9% × 24.5%; OR = 1.57; CI = 1.136–2.194; P = 0.0081), and lower C-peptide levels when compared to those with TC + CC genotypes (0.41 ± 0.30 ng/dL versus 0.70 ± 0.53 ng/dL P = 0.0218). Conclusions. The rs763361 variant of CD226 gene (TT genotype) was associated with susceptibility to T1D and with the degree of aggressiveness of the disease in T1D patients from Brazil. Ancestry had no effect.

Redução da mobilidade funcional e da capacidade cognitiva no diabetes melito tipo 2

OBJECTIVES The aim of the present study was to evaluate the functional mobility and its relationship to cognitive ability in patients with type 2 diabetes (T2DM), age between 50 and 65 years and under 10 years of diagnosis. MATERIALS AND METHODS An observational, analytical and cross-sectional study, involving no diabetic and type 2 diabetic individuals with inadequate glycemic control, selected by convenience sampling. In both groups, were administered structured questionnaire and cognitive assessment with Mini-Mental State Examination (MMSE) and the clock drawing test (CDT), besides assessment of functional mobility by the Timed Up & Go (TUG). RESULTS In TUG, DM2 patients presented a mean time of 11.27 seconds versus 9.52 seconds (p = 0.013). The association between cognitive decline and decrease of mobility was positive in individuals with T2DM (p = 0.037). In the subgroup that showed decrease of mobility and associated cognitive decline, 18% were patients with DM2 and 1.6% were individuals without T2DM (p < 0.01). CONCLUSIONS Patients with T2DM presented worse functional mobility and cognitive performance, supporting the hypothesis that DM2 influence functional mobility and cognitive ability, regardless of neuropathic or vascular complications. These data suggest that hyperglycemia is an aggravating factor in the performance of activities requiring mental functions such as attention, working memory and orientation.Objectives: The aim of the present study was to evaluate the functional mobility and its relationship to cognitive ability in patients with type 2 diabetes (T2DM), age between 50 and 65 years and under 10 years of diagnosis. Materials and methods: An observational, analytical and cross-sectional study, involving no diabetic and type 2 diabetic individuals with inadequate glycemic control, selected by convenience sampling. In both groups, were administered structured questionnaire and cognitive assessment with Mini-Mental State Examination (MMSE) and the clock drawing test (CDT), besides assessment of functional mobility by the Timed Up & Go (TUG). Results: In TUG, DM2 patients presented a mean time of 11.27 seconds versus 9.52 seconds (p = 0.013). The association between cognitive decline and decrease of mobility was positive in individuals with T2DM (p = 0.037). In the subgroup that showed decrease of mobility and associated cognitive decline, 18% were patients with DM2 and 1.6% were individuals without T2DM (p < 0.01). Conclusions: Patients with T2DM presented worse functional mobility and cognitive performance, supporting the hypothesis that DM2 influence functional mobility and cognitive ability, regardless of neuropathic or vascular complications. These data suggest that hyperglycemia is an aggravating factor in the performance of activities requiring mental functions such as attention, working memory and orientation.

Diabetes autoimune em adultos: características clínicas e autoanticorpos

The prevalence of anti-insulin (IAA), anti-glutamic acid decarboxylase 65 (anti-GAD) and anti-islet cell antibodies (ICA) and the clinical and metabolic findings of 66 patients with adult-onset diabetes mellitus (DM) manifested at 47.2±11.6 years with known duration of 14.3±8.4y were determined. RESULTS: ICA was positive in 10 cases (10 to 640 JDF U), 3 of them being also positive for anti-GAD (15.6 to 113.5 U/ml) and one for IAA (in those without previous insulin therapy). 15.2% of the patients had one or more autoantibodies, with greater prevalence for ICA. There were no differences between patients with and without autoantibodies for clinical DM presentation and prevalence of chronic complications. Only the cholesterol levels were lower in the antibody positive group (205.2±49.6 vs. 247.1±61.3mg/dl; p<0.05). CONCLUSION: 15.2% of the adult-onset DM had one or more autoantibodies, with greater prevalence for ICA. Autoantibodies determination is necessary for the diagnosis of autoimmune DM.

Short and Long Term Effects of a DPP-4 Inhibitor Versus Bedtime NPH Insulin as ADD-ON Therapy in Patients with Type 2 Diabetes

BACKGROUND We conducted a comparison between the dipeptidyl-peptidase-4(DPP-4) inhibitor sitagliptin versus NPH insulin as an add-on therapies in patients with type 2 diabetes mellitus (T2D) failing oral medications. The objective was to ascertain the better indication in long-duration diabetes. METHODS thirty-five T2D patients inadequately controlled with metformin plus glyburide were randomized to receive sitagliptin (n=18) or bedtime NPH insulin (n=17) for 12 months. HbA1c levels and a metabolic and hormonal profile at fasting and post-meal (every 30 minutes for 4 hours) were evaluated before and after 6 months (short-term) and 12 months (long-term) after adding sitagliptin or bedtime NPH insulin to their drug regime. RESULTS Sitagliptin and NPH insulin decreased HbA1c levels equally after 6 months (p<0.001) with no further improvement after 12 months: sitagliptin (8.1±0.7% vs. 7.3±0.8% vs. 7.4±1.9%) and insulin (8.1±0.6% vs. 7.3±0.7% vs. 7.2±1.0%). Fasting glucose, fasting and postprandial triglyceride and C-peptide levels were also reduced by NPH insulin whereas postprandial insulin was decreased by sitagliptin. Body weight and postchallenge free fatty acid levels increased with insulin treatment. The transitory suppression (at 6 months) of postprandial proinsulin levels with both therapies, and of glucagon with sitagliptin, was followed by values similar or worse to those at pre-treatment. CONCLUSION The use of either NPH insulin or a DPP-4 inhibitor as add-on treatments improves glucose control in patients with T2D failing on metformin plus glyburide therapy. The results were not attributed to a permanent improvement in alpha or beta cell function in patients with long-duration diabetes.

Comparative effects of a dipeptidyl peptidase-4 inhibitor and of NPH insulin on peripheral nerve conduction of patients with type 2 diabetes

Background Studies in animals have suggested that the glucagon-like peptide-1 hormone (GLP-1) has neurotrophic properties that were independent of those related to the improvement of glucose control. Dipeptidyl peptidase-4 (DPP-4) inhibitors increase GLP-1 levels and are effective in improving metabolic parameters in patients with type 2 diabetes mellitus (T2D) but little is known about its effects on neurological disorders, including peripheral diabetic neuropathy.