Association of fat mass and obesity-associated (FTO) gene rs9939609 with obesity-related traits and glucose intolerance in an indigenous population, the Xavante.

BACKGROUND AND AIMS: Common variants in fat mass and obesity-associated (FTO) gene have been implicated as a susceptibility locus for obesity and type 2 diabetes in different populations. Here, in an indigenous population-based study, we examined whether FTO rs9939609 has a role in susceptibility to glucose intolerance and obesity. METHODS: The study population comprised 949 full Xavante indigenous people (465 men) aged 18-99 years. The participants were submitted to clinical examination, anthropometrical measures and basal and 2-h post 75g oral glucose load capillary glucose measurements. FTO rs9939609 was genotyped and logistic regression was carried out to test the additive effect of the risk allele. RESULTS: The frequency of the minor allele of the FTO rs9939609 (0.06) was lower in Xavante than observed in some populations. A significant association between the variant and overweight was observed (OR = 1.56 (95% CI:1.06-2.29, p = 0.02), using an additive model of inheritance, adjusted by age and gender and considering the family structure. We found no associations with obesity or glucose intolerance. CONCLUSIONS: The FTO rs9939609 is associated with overweight, but not with obesity or glucose intolerance. The low frequency of the A allele suggests that it is not an important risk determinant for these conditions in Xavante indigenous people.

Global Deletion of the Prolactin Receptor Aggravates Streptozotocin-Induced Diabetes in Mice.

Prolactin (PRL) levels are reduced in the circulation of rats with diabetes or obesity, and lower circulating levels of PRL correlate with increased prevalence of diabetes and a higher risk of metabolic alterations in the clinic. Furthermore, PRL stimulates ß-cell proliferation, survival, and insulin production and pregnant mice lacking PRL receptors in ß-cells develop gestational diabetes. To investigate the protective effect of endogenous PRL against diabetes outside pregnancy, we compared the number of cases and severity of streptozotocin (STZ)-induced hyperglycemia between C57BL/6 mice null for the PRL receptor gene (Prlr-/- ) and wild-type mice (Prlr+/+ ). STZ-treated diabetic Prlr-/- mice showed a higher number of cases and later recovery from hyperglycemia, exacerbated glucose levels, and glucose intolerance compared to the Prlr+/+ mice counterparts. Consistent with the worsening of hyperglycemia, pancreatic islet density, ß-cell number, proliferation, and survival, as well as circulating insulin levels were reduced, whereas α-cell number and pancreatic inflammation were increased in the absence of PRL signaling. Deletion of the PRL receptor did not alter the metabolic parameters in vehicle-treated animals. We conclude that PRL protects whole body glucose homeostasis by reducing ß-cell loss and pancreatic inflammation in STZ-induced diabetes. Medications elevating PRL circulating levels may prove to be beneficial in diabetes.

Nlrp1b1 negatively modulates obesity-induced inflammation by promoting IL-18 production.

Obesity-induced inflammation, triggered by lipid-mediated activation of the Nlrp3 inflammasome, results in glucose metabolism alterations and type 2 diabetes. This knowledge has been generated using animals deficient for any of the different components of this inflammasome (Caspase-1, Asc or Nlrp3) in the C57BL/6 background. Unlike C57BL/6 mice, which carry allele 2 of the Nlrp1b gene (Nlrp1b2), Balb/c mice that carry allele 1 (Nlrp1b1) are less prone to develop alterations in the glucose metabolism when fed with a high fat diet. However, the molecular bases for these metabolic differences are unknown. Here we show that the Nlrp1b1 allele down regulates the adipose tissue inflammatory response attenuating glucose intolerance and insulin resistance in obese C57BL/mice. Our results indicate that the positive effects of the Nlrp1b1 inflammasome on glucose tolerance and insulin sensitivity involve IL-18-mediated effects on lipolysis, pointing out that differential expression of allelic variants of genes coding for inflammasome components might control susceptibility or resistance to develop diabetes in obese individuals.

Central growth hormone action regulates metabolism during pregnancy.

The maternal organism undergoes numerous metabolic adaptations to become prepared for the demands associated with the coming offspring. These metabolic adaptations involve changes induced by several hormones that act at multiple levels, ultimately influencing energy and glucose homeostasis during pregnancy and lactation. Previous studies have shown that central growth hormone (GH) action modulates glucose and energy homeostasis. However, whether central GH action regulates metabolism during pregnancy and lactation is still unknown. In the present study, we generated mice carrying ablation of GH receptor (GHR) in agouti-related protein (AgRP)-expressing neurons, in leptin receptor (LepR)-expressing cells or in the entire brain to investigate the role played by central GH action during pregnancy and lactation. AgRP-specific GHR ablation led to minor metabolic changes during pregnancy and lactation. However, while brain-specific GHR ablation reduced food intake and body adiposity during gestation, LepR GHR knockout (KO) mice exhibited increased leptin responsiveness in the ventromedial nucleus of the hypothalamus during late pregnancy, although their offspring showed reduced growth rate. Additionally, both Brain GHR KO and LepR GHR KO mice had lower glucose tolerance and glucose-stimulated insulin secretion during pregnancy, despite presenting increased insulin sensitivity, compared with control pregnant animals. Our findings revealed that during pregnancy central GH action regulates food intake, fat retention, as well as the sensitivity to insulin and leptin in a cell-specific manner. Together, the results suggest that GH acts in concert with other "gestational hormones" to prepare the maternal organism for the metabolic demands of the offspring.

Microbiota determines insulin sensitivity in TLR2-KO mice.

INTRODUCTION: Environmental factors have a key role in the control of gut microbiota and obesity. TLR2 knockout (TLR2-/-) mice in some housing conditions are protected from diet-induced insulin resistance. However, in our housing conditions these animals are not protected from diet-induced insulin-resistance. AIM: The aim of the present study was to investigate the influence of our animal housing conditions on the gut microbiota, glucose tolerance and insulin sensitivity in TLR2-/- mice. MATERIAL AND METHODS: The microbiota was investigated by metagenomics, associated with hyperinsulinemic euglycemic clamp and GTT associated with insulin signaling through immunoblotting. RESULTS: The results showed that TLR2-/- mice in our housing conditions presented a phenotype of metabolic syndrome characterized by insulin resistance, glucose intolerance and increase in body weight. This phenotype was associated with differences in microbiota in TLR2-/- mice that showed a decrease in the Proteobacteria and Bacteroidetes phyla and an increase in the Firmicutesphylum, associated with and in increase in the Oscillospira and Ruminococcus genera. Furthermore there is also an increase in circulating LPS and subclinical inflammation in TLR2-/-. The molecular mechanism that account for insulin resistance was an activation of TLR4, associated with ER stress and JNK activation. The phenotype and metabolic behavior was reversed by antibiotic treatment and reproduced in WT mice by microbiota transplantation. CONCLUSIONS: Our data show, for the first time, that the intestinal microbiota can induce insulin resistance and obesity in an animal model that is genetically protected from these processes.

Fish Oil Protects Wild Type and Uncoupling Protein 1-Deficient Mice from Obesity and Glucose Intolerance by Increasing Energy Expenditure.

SCOPE: The mechanisms and involvement of uncoupling protein 1 (UCP1) in the protection from obesity and insulin resistance induced by intake of a high-fat diet rich in omega-3 (n-3) fatty acids are investigated. METHODS AND RESULTS: C57BL/6J mice are fed either a low-fat (control group) or one of two isocaloric high-fat diets containing either lard (HFD) or fish oil (HFN3) as fat source and evaluated for body weight, adiposity, energy expenditure, glucose homeostasis, and inguinal white and interscapular brown adipose tissue (iWAT and iBAT, respectively) gene expression, lipidome, and mitochondrial bioenergetics. HFN3 intake protected from obesity, glucose and insulin intolerances, and hyperinsulinemia. This is associated with increased energy expenditure, iWAT UCP1 expression, and incorporation of n-3 eicosapentaenoic and docosahexaenoic fatty acids in iWAT and iBAT triacylglycerol. Importantly, HFN3 is equally effective in reducing body weight gain, adiposity, and glucose intolerance and increasing energy expenditure in wild-type and UCP1-deficient mice without recruiting other thermogenic processes in iWAT and iBAT, such as mitochondrial uncoupling and SERCA-mediated calcium and creatine-driven substrate cyclings. CONCLUSION: Intake of a high-fat diet rich in omega-3 fatty acids protects both wild-type and UCP1-deficient mice from obesity and insulin resistance by increasing energy expenditure through unknown mechanisms.

Relationship of lactation, BMI, and rs12255372 TCF7L2 polymorphism on the conversion to type 2 diabetes mellitus in women with previous gestational diabetes.

Women with previous gestational diabetes mellitus (pGDM) have a high risk of developing postpartum type 2 diabetes mellitus (T2DM). This study aimed to analyze the relationship between lactation, BMI, and TCF7L2 polymorphisms in the conversion to T2DM in women with pGDM. One hundred and fifty-three women con pGDM were recruited from public hospitals of León Guanajuato México. Three groups: normal glucose tolerance (NGT), impaired glucose intolerance (IGT), and T2DM after the oral glucose tolerance test were formed. Metabolic and hormone variables were measured, and genotyping was made by PCR-RFLP. The questionnaire included data on lactation (yes/no), duration of lactation, and full lactation. After 35 (21-49) months from the last partum, 54% of women had an NGT, 30.7% IGT, and 15% T2DM. BMI and rs12255372 are associated with the risk of conversion to IGT and T2DM [OR = 1.07 (95% IC 1.0-1.14, p = .041; OR =2.14, 95% IC 1.01-4.55, p = .04 respectively), while the lactation shows a strong protective effects OR = 0.15 (95% IC 0.062-0.39, p = .00007), and an apparent interaction with rs12255372T decreasing the risk in carriers (OR =2.15; 95% IC 0.97-4.7, p = .05). BMI is an independent risk factor of IGT/T2DM development. The lactation shows a strong protective effect and a possible interaction with rs12255372 polymorphism.

Zinc and Insulin Resistance: Biochemical and Molecular Aspects.

Studies have shown the participation of minerals in mechanisms involved in the pathogenesis of insulin resistance. Zinc, in particular, seems to play an important role in the secretion and action of this hormone. Therefore, the aim of this review is to understand the role of zinc in increasing insulin sensitivity. We conducted a search of articles published in the PubMed and ScienceDirect database selected from March 2016 to February 2018, using the keywords "zinc," "insulin," "insulin resistance," "insulin sensitivity," and "supplementation." Following the eligibility criteria were selected 53 articles. The scientific evidences presented in this review show the importance of zinc and their carrier proteins in the synthesis and secretion of insulin, as well as in the signaling pathway of action of this hormone. Zinc deficiency is associated with glucose intolerance and insulin resistance; however, the effectiveness of the intervention with the zinc supplementation is still inconclusive.

PDX1 -MODY and dorsal pancreatic agenesis: New phenotype of a rare disease.

Maturity-Onset Diabetes of the Young (MODY) type 4 or PDX1 -MODY is a rare form of monogenic diabetes caused by heterozygous variants in PDX1 . Pancreatic developmental anomalies related to PDX1 are reported only in neonatal diabetes cases. Here, we describe dorsal pancreatic agenesis in 2 patients with PDX1 -MODY. The proband presented with diabetes since 14 years of age and maintained regular glycemic control with low doses of basal insulin and detectable C-peptide levels after 38 years with diabetes. A diagnosis of MODY was suspected. Targeted next-generation sequencing identified a heterozygous variant in PDX1 : c.188delC/p.Pro63Argfs*60. Computed tomography revealed caudal pancreatic agenesis. Low fecal elastase indicated exocrine insufficiency. His son had impaired glucose tolerance, presented similar pancreatic agenesis, and harbored the same allelic variant. The unusual presentation in this Brazilian family enabled expansion upon a rare disease phenotype, demonstrating the possibility of detecting pancreatic malformation even in cases of PDX1 -related diabetes diagnosed after the first year of life. This finding can improve the management of MODY4 patients, leading to precocious investigation of pancreatic dysgenesis and exocrine dysfunction.

Fine particulate matter potentiates type 2 diabetes development in high-fat diet-treated mice: stress response and extracellular to intracellular HSP70 ratio analysis.

Exposure to fine particulate matter (PM2.5) air pollution is a risk factor for type 2 diabetes (T2DM). We argue whether the potentiating effect of PM2.5 over the development of T2DM in high-fat diet (HFD)-fed mice would be related to modification in cell stress response, particularly in antioxidant defenses and 70-kDa heat shock proteins (HSP70) status. Male mice were fed standard chow or HFD for 12 weeks and then randomly exposed to daily nasotropic instillation of PM2.5 for additional 12 weeks under the same diet schedule, divided into four groups (n = 14-15 each): Control, PM2.5, HFD, and HFD + PM2.5 were evaluated biometric and metabolic profiles of mice, and cellular stress response (antioxidant defense and HSP70 status) of metabolic tissues. Extracellular to intracellular HSP70 ratio ([eHSP72]/[iHSP70]), viz. H-index, was then calculated. HFD + PM2.5 mice presented a positive correlation between adiposity, increased body weight and glucose intolerance, and increased glucose and triacylglycerol plasma levels. Pancreas exhibited lower iHSP70 expression, accompanied by 3.7-fold increase in the plasma to pancreas [eHSP72]/[iHSP70] ratio. Exposure to PM2.5 markedly potentiated metabolic dysfunction in HFD-treated mice and promoted relevant alteration in cell stress response assessed by [eHSP72]/[iHSP70], a relevant biomarker of chronic low-grade inflammatory state and T2DM risk.

Hyperprolactinemia induced by hCG leads to metabolic disturbances in female mice.

The metabolic syndrome is a growing epidemic; it increases the risk for diabetes, cardiovascular disease, fatty liver, and several cancers. Several reports have indicated a link between hormonal imbalances and insulin resistance or obesity. Transgenic (TG) female mice overexpressing the human chorionic gonadotropin ß-subunit (hCGß+ mice) exhibit constitutively elevated levels of hCG, increased production of testosterone, progesterone and prolactin, and obesity. The objective of this study was to investigate the influence of hCG hypersecretion on possible alterations in the glucose and lipid metabolism of adult TG females. We evaluated fasting serum insulin, glucose, and triglyceride levels in adult hCGß+ females and conducted intraperitoneal glucose and insulin tolerance tests at different ages. TG female mice showed hyperinsulinemia, hypertriglyceridemia, and dyslipidemia, as well as glucose intolerance and insulin resistance at 6 months of age. A 1-week treatment with the dopamine agonist cabergoline applied on 5-week-old hCGß+ mice, which corrected hyperprolactinemia, hyperandrogenism, and hyperprogesteronemia, effectively prevented the metabolic alterations. These data indicate a key role of the hyperprolactinemia-induced gonadal dysfunction in the metabolic disturbances of hCGß+ female mice. The findings prompt further studies on the involvement of gonadotropins and prolactin on metabolic disorders and might pave the way for the development of new therapeutic strategies.

MicroRNA Expression Signature Is Altered in the Cardiac Remodeling Induced by High Fat Diets.

Recent studies have revealed the involvement of microRNAs (miRNAs) in the control of cardiac hypertrophy and myocardial function. In addition, several reports have demonstrated that high fat (HF) diet induces cardiac hypertrophy and remodeling. In the current study, we investigated the effect of diets containing different percentages of fat on the cardiac miRNA expression signature. To address this question, male C57Bl/6 mice were fed with a low fat (LF) diet or two HF diets, containing 45 kcal% fat (HF45%) and 60 kcal% fat (HF60%) for 10 and 20 weeks. HF60% diet promoted an increase on body weight, fasting glycemia, insulin, leptin, total cholesterol, triglycerides, and induced glucose intolerance. HF feeding promoted cardiac remodeling, as evidenced by increased cardiomyocyte transverse diameter and interstitial fibrosis. RNA sequencing analysis demonstrated that HF feeding induced distinct miRNA expression patterns in the heart. HF45% diet for 10 and 20 weeks changed the abundance of 64 and 26 miRNAs in the heart, respectively. On the other hand, HF60% diet for 10 and 20 weeks altered the abundance of 27 and 88 miRNAs in the heart, respectively. Bioinformatics analysis indicated that insulin signaling pathway was overrepresented in response to HF diet. An inverse correlation was observed between cardiac levels of GLUT4 and miRNA-29c. Similarly, we found an inverse correlation between expression of GSK3ß and the expression of miRNA-21a-3p, miRNA-29c-3p, miRNA-144-3p, and miRNA-195a-3p. In addition, miRNA-1 overexpression prevented cardiomyocyte hypertrophy. Taken together, our results revealed differentially expressed miRNA signatures in the heart in response to different HF diets. J. Cell. Physiol. 231: 1771-1783, 2016. © 2015 Wiley Periodicals, Inc.

Símdrome de Silver-Russell (hemihipertrofia) y cor triatriatum en un neonato / Silver-Russell syndrome (hemihypertrophy) and cor triatriatum in a newborn

Tanto el síndrome de hemihipertrofia como el cor triatriatum son patologías sumamente infrecuentes. La hemihipertrofia se define como el sobrecrecimiento completo o parcial de uno de los hemicuerpos. El cor triatriatum es una cardiopatía congénita caracterizada por una membrana que divide la aurícula izquierda en dos cámaras; si esta membrana tiene un orificio restrictivo, provoca obstrucción al pasaje sanguíneo desde las venas pulmonares hacia el ventrículo izquierdo, lo que genera hipertensión y edema pulmonar. En este contexto, el ductus arterioso permeable puede actuar como vía de descompresión del circuito pulmonar al permitir el pasaje sanguíneo desde la arteria pulmonar hacia la aorta. Presentamos a un paciente con diagnóstico de síndrome de Silver-Rusell (hemihipertrofia), cor triatriatum y ductus arterioso con flujo invertido. Hasta donde conocemos, esta asociación de patologías infrecuentes y forma de presentación no se han descrito anteriormente.(AU)

Hemihypertrophy syndrome and cor triatriatum are extremely rare pathologies. Hemihypertrophy is defined as complete or partial overgrowth of one of the hemibodies. Cor triatriatum is a congenital heart disease characterized by a membrane which separates the left atrium into two chambers; if that membrane has a restrictive hole, it causes obstruction to blood passage from the pulmonary veins into the left ventricle causing hypertension and pulmonary edema. In this context, the patent ductus arteriosus can act as a means of decompression of the pulmonary circuit, because it allows the blood passage from the pulmonary artery to the aorta. We report a patient with Silver-Rusell syndrome (hemihypertrophy), cor triatriatum and ductus arteriosus with reverse flow. To our knowledge, this association of rare pathologies and this clinical presentation have not been described previously.(AU)

Símdrome de Silver-Russell (hemihipertrofia) y cor triatriatum en un neonato / Silver-Russell syndrome (hemihypertrophy) and cor triatriatum in a newborn

Tanto el síndrome de hemihipertrofia como el cor triatriatum son patologías sumamente infrecuentes. La hemihipertrofia se define como el sobrecrecimiento completo o parcial de uno de los hemicuerpos. El cor triatriatum es una cardiopatía congénita caracterizada por una membrana que divide la aurícula izquierda en dos cámaras; si esta membrana tiene un orificio restrictivo, provoca obstrucción al pasaje sanguíneo desde las venas pulmonares hacia el ventrículo izquierdo, lo que genera hipertensión y edema pulmonar. En este contexto, el ductus arterioso permeable puede actuar como vía de descompresión del circuito pulmonar al permitir el pasaje sanguíneo desde la arteria pulmonar hacia la aorta. Presentamos a un paciente con diagnóstico de síndrome de Silver-Rusell (hemihipertrofia), cor triatriatum y ductus arterioso con flujo invertido. Hasta donde conocemos, esta asociación de patologías infrecuentes y forma de presentación no se han descrito anteriormente.

Hemihypertrophy syndrome and cor triatriatum are extremely rare pathologies. Hemihypertrophy is defined as complete or partial overgrowth of one of the hemibodies. Cor triatriatum is a congenital heart disease characterized by a membrane which separates the left atrium into two chambers; if that membrane has a restrictive hole, it causes obstruction to blood passage from the pulmonary veins into the left ventricle causing hypertension and pulmonary edema. In this context, the patent ductus arteriosus can act as a means of decompression of the pulmonary circuit, because it allows the blood passage from the pulmonary artery to the aorta. We report a patient with Silver-Rusell syndrome (hemihypertrophy), cor triatriatum and ductus arteriosus with reverse flow. To our knowledge, this association of rare pathologies and this clinical presentation have not been described previously.

Elevated tissue omega-3 fatty acid status prevents age-related glucose intolerance in fat-1 transgenic mice.

The objective of this study was to investigate the impact of elevated tissue omega-3 (n-3) polyunsaturated fatty acids (PUFA) status on age-related glucose intolerance utilizing the fat-1 transgenic mouse model, which can endogenously synthesize n-3 PUFA from omega-6 (n-6) PUFA. Fat-1 and wild-type mice, maintained on the same dietary regime of a 10% corn oil diet, were tested at two different ages (2 months old and 8 months old) for various glucose homeostasis parameters and related gene expression. The older wild-type mice exhibited significantly increased levels of blood insulin, fasting blood glucose, liver triglycerides, and glucose intolerance, compared to the younger mice, indicating an age-related impairment of glucose homeostasis. In contrast, these age-related changes in glucose metabolism were largely prevented in the older fat-1 mice. Compared to the older wild-type mice, the older fat-1 mice also displayed a lower capacity for gluconeogenesis, as measured by pyruvate tolerance testing (PTT) and hepatic gene expression of phosphoenolpyruvate carboxykinase (PEPCK) and glucose 6 phosphatase (G6Pase). Furthermore, the older fat-1 mice showed a significant decrease in body weight, epididymal fat mass, inflammatory activity (NFκ-B and p-IκB expression), and hepatic lipogenesis (acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS) expression), as well as increased peroxisomal activity (70-kDa peroxisomal membrane protein (PMP70) and acyl-CoA oxidase1 (ACOX1) expression). Altogether, the older fat-1 mice exhibit improved glucose homeostasis in comparison to the older wild-type mice. These findings support the beneficial effects of elevated tissue n-3 fatty acid status in the prevention and treatment of age-related chronic metabolic diseases.

[Impaired fasting glucose and postprandial glucose intolerance. The role of immediate family history]. / Hiperglucemia en ayuno e intolerancia a la glucosa. El papel de los antecedentes familiares directos.

OBJECTIVE: to determine the prevalence of impaired fasting glucose (IFG) and postprandial glucose intolerance (PGI) in individuals with diabetic parent and risk factors for developing DM2. METHODS: a cross-sectional study among 162 individuals with father or mother with DM2, age from 30 to 35 years with risk factors for developing DM2 was performed. Fasting plasma glucose was done, and a glucose tolerance curve was taken in those who had IFG. RESULTS: prediabetes was found in 9.8 % (16) [of which 43.8 % (7) presented PGI]; and 90.2 % (146) were normoglycemic. The mean age in patients with IFG and PGI was 33.5 years and in the normoglycemic group was 32.2, t = 8.36, p = 0.004. The mean weight in the IFG and PGI group was 72.58 kg and 69.85 kg in normoglycemic group, t = 1.21 and p = 0.27. Mean BMI, IFG and PGI was 27.78 and in normoglycemic 26.58, t = 5.25, p = 0.02. CONCLUSIONS: the results suggested that in descents from parents with DM2 with risk factors we must investigate early prediabetes or IFG with fasting plasma glucose.

Objetivo: determinar la frecuencia de alteración de glucosa en ayunas (AGA) e intolerancia a la glucosa postprandial (IGP) en individuos con padre o madre diabéticos y con factores de riesgo para DM2. Método: estudio transversal en 162 hijos de padre o madre con DM2, de 30 a 35 años con factores de riesgo asociados a DM2. Se realizó glucosa plasmática de ayuno y a aquellos con AGA se les realizó curva de tolerancia a la glucosa. Resultados: se encontró prediabetes en 9.8 % (16) [de estos, el 43.8 % (7) presentó IGP] y 90.2 % (146) presentó normoglucemia. La media de edad en individuos con AGA e IGP fue 33.5 años. En los normo-glucémicos fue 32.2, t = 8.36, p = 0.004. La media del peso en AGA e IGP fue de 72.58 kg, y en normoglucémicos de 69.85 kg con t = 1.21 y p = 0.27. La media del IMC en AGA e IGP fue de 27.78, y en normoglucémicos de 26.58, t = 5.25, p = 0.02. Conclusión: Los resultados sugieren que en hijos de padre o madre diabéticos con factores de riesgo debe realizarse glucemia de ayuno para identificar tempranamente prediabetes o IGP.

Double-stranded RNA-activated protein kinase is a key modulator of insulin sensitivity in physiological conditions and in obesity in mice.

The molecular integration of nutrient- and pathogen-sensing pathways has become of great interest in understanding the mechanisms of insulin resistance in obesity. The double-stranded RNA-dependent protein kinase (PKR) is one candidate molecule that may provide cross talk between inflammatory and metabolic signaling. The present study was performed to determine, first, the role of PKR in modulating insulin action and glucose metabolism in physiological situations, and second, the role of PKR in insulin resistance in obese mice. We used Pkr(-/-) and Pkr(+/+) mice to investigate the role of PKR in modulating insulin sensitivity, glucose metabolism, and insulin signaling in liver, muscle, and adipose tissue in response to a high-fat diet. Our data show that in lean Pkr(-/-) mice, there is an improvement in insulin sensitivity, and in glucose tolerance, and a reduction in fasting blood glucose, probably related to a decrease in protein phosphatase 2A activity and a parallel increase in insulin-induced thymoma viral oncogene-1 (Akt) phosphorylation. PKR is activated in tissues of obese mice and can induce insulin resistance by directly binding to and inducing insulin receptor substrate (IRS)-1 serine307 phosphorylation or indirectly through modulation of c-Jun N-terminal kinase and inhibitor of κB kinase ß. Pkr(-/-) mice were protected from high-fat diet-induced insulin resistance and glucose intolerance and showed improved insulin signaling associated with a reduction in c-Jun N-terminal kinase and inhibitor of κB kinase ß phosphorylation in insulin-sensitive tissues. PKR may have a role in insulin sensitivity under normal physiological conditions, probably by modulating protein phosphatase 2A activity and serine-threonine kinase phosphorylation, and certainly, this kinase may represent a central mechanism for the integration of pathogen response and innate immunity with insulin action and metabolic pathways that are critical in obesity.

Association of the CD36 gene with impaired glucose tolerance, impaired fasting glucose, type-2 diabetes, and lipid metabolism in essential hypertensive patients.

Essential hypertension is a common disorder that can increase the risk of type 2 diabetes (T2D). CD36 has been studied in patients with diabetes and hypertension extensively; however, few studies have focused on the relationship of the CD36 gene with impaired fasting glucose (IFG)/impaired glucose tolerance (IGT) or T2D in essential hypertension patients. To identify rs1049673 and rs1527483 in the CD36 gene conferring susceptibility to IFG/IGT and T2D, we conducted a case-control study in 1257 essential hypertension patients among the Han Chinese population (control: 676; IGT/IFG: 468; T2D: 113). We also evaluated the impact of two loci on insulin sensitivity, glucose tolerance and serum lipid. The major findings of this study were that rs1049673 was found associated with IFG/IGT and T2D in essential hypertension patients (Pco = 0.028; Pdom = 0.015). The rs1049673 G carriers showed significant higher Glu0 (ßdom = 0.08 (0.01~0.16), Pdom = 0.045) and Lp(a) (ßco = 0.04 (0.002~0.07), Pco = 0.041; ßdom = 0.06 (0.01~0.12), Pdom = 0.032), and lower HDL by the linear regression with the adjustment for gender, age, BMI, and mean blood pressures. These findings provided evidence that the CD36 gene may play some role in the pathogenesis of IFG/IGT and T2D in essential hypertension patients.

Risk of glycemic disorder in elderly women adjusted by anthropometric parameters and cytokine genotypes.

OBJECTIVE: The objective of the present study was to examine the association of glucose intolerance and type-2 diabetes mellitus with the -174 G > C and -308 G > A allelic variations of IL-6 and TNF-α, respectively, through anthropometric measurements and age strata. METHODS: This is a cross-sectional study using data from 285 community dwelling elderly women who underwent physical, biochemical, and genetic examinations. RESULT: Genotype-unadjusted analysis revealed that the risk of glucose intolerance and diabetes in elderly women with elevated BMI was 1.71 and 2.82 times higher, respectively, whereas age and conicity index did not show predictive value. Prevalence ratios for glucose intolerance and diabetes across allelic variants of IL-6 and TNF-α did not associate IL-6 with unbalanced glucose levels, despite adjustment for BMI, age, and conicity index. Conversely, carriers of the TNF-α A allele were 2.06 and 5.58 times more likely to exhibit glucose intolerance and diabetes, respectively, compared to GG homozygotes. CONCLUSION: Our results suggest that bearing the A allele of the -308 G > A polymorphism of TNF-α predisposes to anthropometric measure-sensitive impaired glucose metabolism in older women.

Risco de distúrbio glicêmico em mulheres idosas ajustado por antropometria e genótipos de citocinas / Risk of glycemic disorder in elderly women adjusted by anthropometric parameters and cytokine genotypes

OBJETIVO: Analisar a associação da intolerância à glicose e do diabetes mellitus tipo 2 com as variações alélicas -174 G > C e -308 G > A de IL-6 e TNF-α, respectivamente, à luz de indicadores antropométricos e faixa etária. MÉTODOS: Trata-se de um estudo transversal com dados obtidos de 285 mulheres idosas da comunidade, submetidas a exames físicos, bioquímicos e genéticos. RESULTADOS: Análise não ajustada para genótipos revelou que idosas com IMC elevado apresentaram risco 1,71 e 2,82 vezes maior para intolerância à glicose e diabetes, respectivamente, enquanto faixa etária e índice de conicidade não apresentaram qualquer valor preditivo. Razões de prevalência para intolerância à glicose e diabetes conforme variantes alélicas de IL-6 e TNF-α não associam genótipos de IL-6 com desregulação glicêmica, a despeito de ajustes para IMC, idade e índice de conicidade. Por outro lado, portadores do alelo A de TNF-α apresentaram 2,06 e 5,58 vezes mais chance de intolerância à glicose e diabetes, respectivamente, comparadas a homozigotas GG no estrato com IMC < 27 kg/m². CONCLUSÃO: Os resultados sugerem que o alelo A do polimorfismo -308 G > A de TNF-α predispõe a distúrbios do metabolismo glicêmico em mulheres idosas de um modo sensível a medidas antropométricas.

OBJECTIVE: The objective of the present study was to examine the association of glucose intolerance and type-2 diabetes mellitus with the -174 G > C and -308 G > A allelic variations of IL-6 and TNF-α, respectively, through anthropometric measurements and age strata. METHODS: This is a cross-sectional study using data from 285 community dwelling elderly women who underwent physical, biochemical, and genetic examinations. RESULT: Genotype-unadjusted analysis revealed that the risk of glucose intolerance and diabetes in elderly women with elevated BMI was 1.71 and 2.82 times higher, respectively, whereas age and conicity index did not show predictive value. Prevalence ratios for glucose intolerance and diabetes across allelic variants of IL-6 and TNF-α did not associate IL-6 with unbalanced glucose levels, despite adjustment for BMI, age, and conicity index. Conversely, carriers of the TNF-α A allele were 2.06 and 5.58 times more likely to exhibit glucose intolerance and diabetes, respectively, compared to GG homozygotes. CONCLUSION: Our results suggest that bearing the A allele of the -308 G > A polymorphism of TNF-α predisposes to anthropometric measure-sensitive impaired glucose metabolism in older women.