Effect of electroacupuncture at different frequencies on brain insulin signaling transduction pathway in Alzheimer's disease mice / 中国针灸

OBJECTIVE@#To observe the effect of electroacupuncture (EA) at different frequencies on learning and memory functions, as well as the relevant proteins of brain insulin signal transduction pathway in Alzheimer's disease (AD) mice and explore the effect mechanism of EA in treatment of AD.@*METHODS@#Seventy-two SPF Kunming male mice were randomized into a blank group, a sham-operation group, a model group, a 2 Hz EA group, a 15 Hz EA group and a 30 Hz EA group, 12 mice in each one. In the model group and each EA group, AD model were established by the injection with streptozotocin (ST2) solution (8 mg/kg) into the left lateral ventricles. In the sham-operation group, 0.9% sodium chloride solution of the same volume was injected into the left lateral ventricles. After successful modeling, in each EA group, EA was applied at "Baihui" (GV 20), "Dazhui" (GV 14) and "Shenshu" (BL 23) with corresponding frequencies, once daily. One course of EA intervention consisted of 7 treatments and 2 courses were given totally at interval of 1 day. After modeling and intervention, Morris water maze test was conducted for the mice of each group. Using immunohistochemistry and Western blot method, the protein expression of insulin receptor (IR), insulin receptor substrate-1 (IRS-1) and phosphatidylinositol 3-kinase (PI3K) was detected in the hippocampal of the mice after intervention.@*RESULTS@#Compared with the blank group, in the model group, the 2 Hz, 15 Hz and 30 Hz EA groups, the escape latency and the first time of crossing the platform were all extended (P<0.01), and the number of crossing the platform was reduced (P<0.01) after modeling. When compared with the blank group, the escape latency and the first time of crossing the platform were all extended (P<0.01), and the number of crossing the platform was reduced (P<0.01) in the model group after intervention. In the 2 Hz, 15 Hz and 30 Hz EA groups, the escape latency and the first time of crossing the platform were all shortened (P<0.01), and the number of crossing the platform was increased (P<0.05, P<0.01) after intervention when compared with the model group. The escape latency and the first time of crossing the platform were all shortened (P<0.01, P<0.05), and the number of crossing the platform was increased (P<0.05) in the 15 Hz and 30 Hz EA groups in comparison with the 2 Hz EA group. The protein expression levels of IR, IRS-1 and PI3K were reduced in the model group when compared with those of the blank group (P<0.01, P<0.05); and these protein expression levels were increased in the 15 Hz and 30 Hz EA groups compared with the model group (P<0.05, P<0.01). Compared with the 2 Hz EA group, the protein expression levels of IR, IRS-1 and PI3K were all elevated in the 15 Hz and 30 Hz EA groups (P<0.05).@*CONCLUSION@#The learning and memory function of AD mice may be improved through regulating brain insulin signaling transconduction pathway with electroacupuncture, and electroacupuncture at 15 Hz and 30 Hz obtains the overall better effect compared with the intervention at 2 Hz.

Effect of Prosopis ruscifolia on incretin and insulin secretion in alloxan-induced hyperglycemic rats / Efecto de Prosopis ruscifolia sobre la secreción de incretina e insulina de ratas hiperglicémicas por aloxano

Background: Diabetes mellitus treatment is based on oral hypoglycemic agents or insulin. Medicinal plants constitute an option, and the leaves of Prosopis ruscifolia (Pr) were shown to be effective in reducing glycemia in hyperglycemic animals. Objective: In this paper, we report the effect of P. rusciofolia (Pr) on insulin and incretin secretion in alloxan-induced hyperglycemic rats. Methodology: The effective dose was selected, and four groups (n=10) of Wistar rats were used. Two groups with normal glycemia received water or Pr (75 mg/Kg, per os, p.o.), and two groups with hyperglycemia induced by alloxan (intraperitoneal, ip), received water or Pr (75 mg/Kg, p.o.) for 2 weeks. Oral glucose tolerance test, and incretin and insulin levels were measured at the end of the experimental period. Results: The results showed that extract promotes better tolerance to oral glucose overload, in addition to a statistically significant (p<0.001) increase in blood levels of incretin and insulin, compared to the hyperglycemic rats. Conclusion: It is concluded that the ethanolic extract of P. ruscifolialeaves has a hypoglycemic effect in hyperglycemic animals by a mechanism that involves the incretin-insulin system

Antecedentes: la diabetes mellitus es una enfermedad metabólica cuyo tratamiento se basa en el uso de agentes hipoglicemiantes orales o insulina. Una opción al tratamiento son las plantas medicinales y en ese sentido, estudios previos en animales con hojas de Prosopis ruscifolia (Pr) han demostrado efecto hipoglicemiante. Objetivo: en este trabajo se reporta el efecto de P. rusciofolia (Pr) en la secreción de insulina e incretina, en ratas hiperglicémicas por aloxano. Metodología: se emplearon cuatro grupos de ratas Wistar (n=10). Dos grupos con glicemia normal que fueron tratadas con agua Pr (75 mg/Kg, per os, p.o.) y dos grupos con hiperglicemia inducida por la inyección intraperitoneal de aloxano recibieron agua Pr (75 mg/Kg, per os, p.o.) durante dos semanas. Se midieron la tolerancia oral a la glucosa, y los niveles de incretina e insulina al final del periodo de experimentación. Resultados: se encontró que el extracto promueve una mayor tolerancia a la sobrecarga de glucosa, y además un incremento significativo (p<0.001) de los niveles de incretina e insulina en sangre, comparados al grupo de ratas hiperglicémicas. Conclusión: se concluye que e l estracto etanólico de las hojas de P. ruscifolia tienen efecto hipoglicemiante en animales hiperglicémicos por un mecanismo que incluye al sistema incretina-insulina

Progress in the role of endometrial glucose metabolism in embryo implantation / 生理学报

The synthesis and decomposition of glycogen adjust the blood glucose dynamically to maintain the energy supply required by the cells. As the only hormone that lowers blood sugar in the body, insulin can promote glycogen synthesis by activating the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway and increasing glucose transporter translocation, and inhibit gluconeogenesis to lower blood glucose. In the endometrium, glycogen metabolism is active, but gluconeogenesis does not occur. The glycogen metabolism in the endometrium is controlled not only by the classical glucose regulating hormones, but also by the ovarian hormones. The functional activities related to implantation of the endometrium during the implantation window require glucose as energy source. A large amount of glucose is used to synthesize glycogen in the endometrium before implantation, which could meet the increased energy demand for embryo implantation. In diabetes, glycogen metabolism in the endometrium is impaired, which frequently leads to implantation failure and early abortion. This article reviews the glycogen metabolism in the endometrium and discusses its role in embryo implantation, which provide new ideas for embryo implantation research and infertility treatment.

Effective fraction from Simiao Wan prevents hepatic insulin resistant by inhibition of lipolysis via AMPK activation / 中国天然药物

Simiao Wan (SMW) is a traditional Chinese formula, including Atractylodis Rhizoma, Achyranthis Bidentatae Radix, Phellodendri Chinensis Cortex and Coicis Semen at the ratio of 1:1:2:2. It can be used to the treatment of diabetes. However, its bioactive compounds and underlying mechanism are unclear. This study aimed to screen the antilipolytic fraction from SMW and investigate its therapeutic mechanisms on hepatic insulin resistance. Different fractions of SMW were prepared by membrane separation combined with macroporous resin and their antilipolytic activities were screened in fasted mice. The effects of 60% ethanol elution (ESMW) on lipolysis were investigated in 3T3-L1 adipocytes stimulated by palmitic acid (PA) and high fat diet (HFD)-fed mice. In our study, ESMW is the bioactive fraction responsible for the antilipolytic activity of SMW and 13 compounds were characterized from ESMW by UHPLC-QTOF-MS/MS. ESMW suppressed protein kinase A (PKA)-hormone-sensitive lipase (HSL) related lipolysis and increased AMP-activated protein kinase (AMPK) phosphorylation in PA challenged 3T3-L1 adipocytes. AMPKα knockdown abolished the inhibitory effects of ESMW on IL-6 and HSL pSer-660, revealing that the antilipolytic and anti-inflammatory activities of ESMW are AMPK dependent. Furthermore, ESMW ameliorated insulin resistance and suppressed lipolysis in HFD-fed mice. It inhibited diacylglycerol accumulation in the liver and inhibited hepatic gluconeogenesis. Conditional medium collected from ESMW-treated 3T3-L1 cells ameliorated insulin action on hepatic gluconeogenesis in liver cells, demonstrating the antilipolytic activity contributed to ESMW beneficial effects on hepatic glucose production. In conclusion, ESMW, as the antilipolytic fraction of SMW, inhibited PKA-HSL related lipolysis by activating AMPK, thus inhibiting diacylglycerol (DAG) accumulation in the liver and thereby improving insulin resistance and hepatic gluconeogenesis.

Effect of free fatty acids on insulin secretion, insulin sensitivity and incretin effect - a narrative review

ABSTRACT Deleterious effects of free fatty acids, FFAs, on insulin sensitivity are observed in vivo studies in humans. Mechanisms include impaired insulin signaling, oxidative stress, inflammation, and mitochondrial dysfunction, but the effects on insulin secretion are less well known. Our aim was to review the relationship of increased FFAs with insulin resistance, secretion and mainly with the incretin effect in humans. Narrative review. Increased endogenous or administered FFAs induce insulin resistance. FFAs effects on insulin secretion are debatable; inhibition and stimulation have been reported, depending on the type and duration of lipids exposition and the study subjects. Chronically elevated FFAs seem to decrease insulin biosynthesis, glucose-stimulated insulin secretion and β-cell glucose sensitivity. Lipids infusion decreases the response to incretins with unchanged incretin levels in volunteers with normal glucose tolerance. In contrast, FFAs reduction by acipimox did not restore the incretin effect in type-2 diabetes, probably due to the dysfunctional β-cell. Possible mechanisms of FFAs excess on incretin effect include reduction of the expression and levels of GLP-1 (glucagon like peptide-1) receptor, reduction of connexin-36 expression thus the coordinated secretory activity in response to GLP-1, and GIP (glucose-dependent insulinotropic polypeptide) receptors downregulation in islets cells. Increased circulating FFAs impair insulin sensitivity. Effects on insulin secretion are complex and controversial. Deleterious effects on the incretin-induced potentiation of insulin secretion were reported. More investigation is needed to better understand the extent and mechanisms of β-cell impairment and insulin resistance induced by increased FFAs and how to prevent them.

The role of pioglitazone in antioxidant, anti-inflammatory, and insulin sensitivity in a high fat-carbohydrate diet-induced rat model of insulin resistance

We explored the cascade effects of a high fat-carbohydrate diet (HFCD) and pioglitazone (an anti-diabetic therapy used to treat type 2 diabetes mellitus (T2DM)) on lipid profiles, oxidative stress/antioxidant, insulin, and inflammatory biomarkers in a rat model of insulin resistance. Sixty albino rats (80-90 g) were randomly divided into three dietary groups; 1) standard diet; 2) HFCD diet for 12 weeks to induce an in vivo model of insulin resistance; and 3) HFCD diet plus pioglitazone. Blood and tissue samples were taken to assess hepatic function, lipid profiles, oxidative biomarkers, malondialdehyde (MDA) levels, antioxidant defense biomarkers, including reduced glutathione (GSH), superoxide dismutase (SOD), and the inflammatory markers interleukin-6 (IL-6) and tumor necrotic factor (TNF-α). HFCD-fed rats had significantly (P≤0.05) increased serum triacylglycerol (TG), total cholesterol (TC), low-density lipoprotein (LDL), alanine transaminase (ALT), and bilirubin levels, but decreased high-density lipoprotein (HDL) levels compared with the normal group. Moreover, serum leptin, resistin, TNF-α, and IL-6 levels were increased significantly in HFCD animals compared with controls. Similarly, HFCD-induced insulin resistance caused antioxidant and cytokine disturbances, which are important therapy targets for pioglitazone. Importantly, administration of this drug ameliorated these changes, normalized leptin and resistin and inflammatory markers by reducing TNF-α levels. Metabolic cascades of elevated lipid profiles, oxidative stress, insulin, and inflammatory biomarkers are implicated in insulin resistance progression. HFCD induced metabolic cascades comprising hypertriglyceridemia, hyperglycemia, insulin resistance, obesity-associated hormones, and inflammatory biomarkers may be alleviated using pioglitazone.

Molecular mechanism of geniposide in regulating GLUT2 glycosylation in pancreatic β cells / 中国中药杂志

Type 2 diabetes mellitus( T2 DM) is a common chronic metabolic disease characterized by persistent hyperglycemia and insulin resistance. In pancreatic β-cells,glucose-stimulated insulin secretion( GSIS) plays a pivotal role in maintaining the balance of blood glucose level. Previous studies have shown that geniposide,one of the active components of Gardenia jasminoides,could quickly regulate the absorption and metabolism of glucose,and affect glucose-stimulated insulin secretion in pancreatic β cells,but the specific mechanism needs to be further explored. Emerging evidence indicated that glycosylation of glucose transporter( GLUT) has played a key role in sensing cell microenvironmental changes and regulating glucose homeostasis in eucaryotic cells. In this study,we studied the effects of geniposide on the key molecules of GLUT2 glycosylation in pancreatic β cells. The results showed that geniposide could significantly up-regulate the mRNA and protein levels of Glc NAc T-Ⅳa glycosyltransferase( Gn T-Ⅳa) and galectin-9 but had no signi-ficant effect on the expression of clathrin,and geniposide could distinctively regulate the protein level of Gn T-Ⅳa in a short time( 1 h) under the conditions of low and medium glucose concentrations,but had no significant effect on the protein level of galectin-9. In addition,geniposide could also remarkably affect the protein level of glycosylated GLUT2 in a short-time treatment. The above results suggested that geniposide could quickly regulate the protein level of Gn T-Ⅳa,a key molecule of protein glycosylation in INS-1 rat pancreatic βcells and affect the glycosylation of GLUT2. These findings suggested that the regulation of geniposide on glucose absorption,metabolism and glucose-stimulated insulin secretion might be associated with its efficacy in regulating GLUT2 glycosylation and affecting its distribution on the cell membrane and cytoplasm in pancreatic β cells.

Effects of different types of exercise on lipid uptake, synthesis and oxidation in skeletal muscles of insulin-resistant rats / 生理学报

The present study aims to investigate the effects of aerobic exercise and resistance exercise on lipid metabolism of skeletal muscle in high-fat diet (HFD)-induced insulin-resistant (IR) rats and the underlying mechanisms. Male Sprague-Dawley (SD) rats at age of 10 weeks were fed with HFD for 10 weeks to establish IR model. The IR rats were then randomly assigned into 3 groups, including IR control (IR) group, aerobic exercise (AE) group and resistance exercise (RE) group. An additional chow diet sedentary control (CON) group was used as well. Fasting blood glucose (FBG), insulin (FIN), glucagon and lipids, as well as triacylglycerol (TG), free fatty acids (FFA), and the protein expression of fatty acid translocase/cluster of differentiation 36 (FAT/CD36), carnitine palmitoyltransferase-1 (CPT-1), stearoyl-CoA desaturase-1 (SCD-1) and peroxisome proliferators-activated receptors γ (PPARγ) in skeletal muscles were measured after 8-week exercise interventions. The results showed that the contents of FBG, FIN, and LDL-C were increased by IR compared with CON group, and significantly decreased by aerobic exercise and resistance exercise; while aerobic exercise induced an increase in HDL-C as well. Furthermore, IR exhibited no significant effects on TG content of skeletal muscles, but significantly increased FFA level. Both aerobic and resistance exercise led to a decrease in TG content, and FFA level was increased by aerobic exercise but deceased by resistance exercise. In addition, the protein expression of FAT/CD36, SCD-1 and PPARγ was increased and that of CPT-1 was decreased by IR, while both types of exercise resulted in a decrease in the protein expression of FAT/CD36, SCD-1 and PPARγ, and an increase in CPT-1. In conclusion, aerobic and resistance exercise may attenuate IR through decreasing HFD-induced ectopic fat deposition and increasing β-oxidation of fatty acids in skeletal muscle cells, and resistance exercise shows a greater improvement in lipid metabolism of skeletal muscles than aerobic exercise.

Deletion of CD36 gene ameliorates glucose metabolism abnormality induced by high-fat diet and promotes liver lipid accumulation / 生理学报

This study aimed to investigate the effects and the underlying mechanism of CD36 gene on glucose and lipid metabolism disorder induced by high-fat diet in mice. Wild type (WT) mice and systemic CD36 knockout (CD36

Soluble insulin receptor and metabolic syndrome

The metabolic syndrome describes a group of signs that increase the likelihood for developing type 2 diabetes mellitus, cardiovascular diseases and some types of cancer. The action of insulin depends on its binding to membrane receptors on its target cells. We wonder if blood insulin could travel bound to proteins and if, in the presence of hyperinsulinemia, a soluble insulin receptor might be generated. We used young adult Wistar rats (which have no predisposition to obesity or diabetes), whose drinking water was added 20 % of sugar and that were fed a standard diet ad libitum for two and six months. They were compared with control rats under the same conditions, but that had running water for consumption. At two months, the rats developed central obesity, moderate hypertension, high triglyceride levels, hyperinsulinemia, glucose intolerance and insulin resistance, i.e., metabolic syndrome. Electrophoresis of the rats’ plasma proteins was performed, followed by Western Blot (WB) for insulin and for the outer portion of the insulin receptor. The bands corresponding to insulin and to the receptor external part were at the same molecular weight level, 25-fold higher than that of free insulin. We demonstrated that insulin, both in control animals and in those with hyperinsulinemia, travels bound to the receptor outer portion (ectodomain), which we called soluble insulin receptor, and that is released al higher amounts in response to plasma insulin increase; in rats with metabolic syndrome and hyperinsulinemia, plasma levels are much higher than in controls. Soluble insulin receptor increase in blood might be an early sign of metabolic syndrome.

Correlación del factor neurotrófico derivado del cerebro con los componentes que integran el síndrome metabólico infantil / Correlation of brain derived neurotrophic factor with the components that integrate the child metabolic syndrome

La obesidad infantil representa un factor importante en el desarrollo del síndrome metabólico (SM). En este sentido el factor neurotrófico derivado del cerebro (BDNF: Brain Derived Neurotrophic Factor) interviene en el metabolismo energético así como en vías que controlan el peso corporal y desórdenes metabólicos. El objetivo de este estudio fue determinar si hay una correlación entre el BDNF con los marcadores que definen al síndrome metabólico en una población infantil de México. Se integraron al estudio 100 niños con un rango de edad de 5-13 años, se estratificaron en tres grupos, normo peso, sobrepeso y obesidad, a los cuales se les determinaron las variables antropométricas, percentil de la tensión arterial sistólica y diastólica, concentraciones séricas de glucosa, triglicéridos, colesterol de alta densidad (HDL) y BDNF. Se aplicó ANOVA y una correlación de Pearson. Los resultados muestran que la prevalencia de SM utilizando los criterios de Cook y Weiss fue del 14%, mientras que por la Federación Internacional de Diabetes (IDF) es del 11%. La circunferencia de cintura, triglicéridos, colesterol HDL, presión arterial sistólica/diastólica y glucosa, mostraron diferencias significativas entre los grupos estudiados (*p<0,001). El BDNF se correlacionó positivamente con la desviación estándar del índice de masa corporal de acuerdo con la edad (DE-IMCE) (p=0,01), el percentil del perímetro de la cintura (p=0,00), la presión arterial sistólica (p=0,01) y las concentraciones plasmáticas de glucosa (p=0,02). Estos datos muestran que existe una correlación entre el BDNF con la DE-IMCE, la circunferencia de la cintura, la presión arterial sistólica y glucosa(AU)

Childhood obesity represents an important factor in the development of metabolic syndrome (MS). In this sense, the brain derived neurotrophic factor (BDNF) is involved in energy metabolism as well as in pathways that control body weight and metabolic disorders. The objective of this study was to determine if there is a correlation between BDNF with the markers that define the metabolic syndrome in a child population in Mexico. The study included 100 children with an age range of 5-13 years, stratified into three groups, normal weight, overweight and obesity, which were determined anthropometric variables, percentile of systolic and diastolic blood pressure, concentrations serum glucose, triglycerides, high density cholesterol (HDL) and BDNF. ANOVA and Pearson correlation were applied. The results show that the prevalence of MS using the Cook and Weiss criteria was 14%, while for the International Diabetes Federation (IDF) it is 11%. Waist circumference, triglycerides, HDL cholesterol, systolic/diastolic blood pressure and glucose showed significant differences between the groups studied (*p<0.001). The BDNF was positively correlated with the standard deviation of the body mass index according to age (DE-IMCE) (p=0.01), the percentile of the waist circumference (p=0.00), systolic blood pressure (p=0.01) and plasma glucose concentrations (p=0.02). These data show that there is a correlation between BDNF with DE-IMCE, waist circumference, systolic blood pressure and glucose(AU)

Effect of Linagliptin versus Metformin on Insulin Secretion, Insulin Sensitivity and Glucose Control in Subjects with Impaired Glucose Tolerance / Efecto de la Linagliptina Frente a la Metformina en la Secreción de Insulina, Sensibilidad a la Insulina y Control de la Glucosa en Sujetos con Intolerancia a la Glucosa

ABSTRACT Aim: The aim of the study is to evaluate the effect of linagliptin versus metformin on insulin secretion, insulin sensitivity and glucose control in patients with impaired glucose tolerance (IGT). Patients and methods: A randomized, double-blind, clinical trial with parallel groups was per-formed on 16 adults with IGT. Lipid profile and haemoglobin (HbA1c) were evaluated prior to and after the intervention. Glucose and insulin were measured at 0, 30, 60, 90 and 120 minutes after a 75-g oral dextrose load. Eight patients received metformin (500 mg) twice a day before meals for three months. The remaining eight patients received placebo (500 mg) in the morning and linagliptin (5 mg) in the evening before meals. The area under the curve (AUC) of glucose and insulin, total insulin secretion, first-phase of insulin secretion, and insulin sensitivity were assessed. Results: After linagliptin administration, a significant decrease in glucose at 90 minutes (10.8 ± 2.6 vs 7.9 ± 2.2 mmol/L, p < 0.05), 120 minutes (8.8 ± 0.9 vs 6.5 ± 2.1 mmol/L, p < 0.05) and AUC of glucose (1168 ± 210 vs 953 ± 207 mmol/L, p < 0.05) were observed. Metformin administration decreased insulin significantly at 0 minutes (94.8 ± 25.8 vs 73.8 ± 24.6 pmol/L, p < 0.05). Conclusion: Three-month administration of linagliptin in patients with IGT decreased glucose at 90 and 120 minutes after a 75-g oral dextrose load and AUC of glucose. Metformin decreased insulin at 0 minutes.

RESUMEN Objetivo: El objetivo del estudio es evaluar el efecto de la linagliptina frente a la metformina en la secreción de insulina, la sensibilidad a la insulina, y el control de la glucosa en pacientes con intolerancia a la glucosa (IG). Pacientes y métodos: Se realizó un ensayo clínico aleatorio de doble ciego con grupos paralelos a 16 adultos con IG. El perfil lipídico y la hemoglobina (Hba1C) se evaluaron antes y después de la intervención. La glucosa y la insulina se midieron a los 0, 30, 60, 90 y 120 minutos después de un carga oral de 75-g dextrosa. Ocho pacientes recibieron metformina (500 mg) dos veces al día antes de las comidas por tres meses. Los ocho pacientes restantes recibieron placebo (500 mg) por la mañana y linagliptina (5 mg) por la noche antes de las comidas. El área bajo la curva (ABC) de la glucosa y la insulina, la secreción total de insulina, la primera fase de la secreción de insulina, y la sensibilidad a la insulina, fueron evaluadas. Resultados: Luego de la administración de la linagliptina, se observó una disminución significativa de la glucosa a los 90 minutos (10.8 ± 2.6 vs 7.9 ± 2.2 mmol/L, p < 0.05), 120 minutos (8.8 ± 0.9 mmol/L p < 0.05) y el ABC de la glucosa (1168 ± 210 vs 953 ± 207 mmol/L, p < 0.05). La administración de metformina redujo significativamente la insulina a los 0 minutos (94.8 ± 25.8 vs 73.8 ± 24.6 pmol/L, p < 0.05). Conclusión: Tres meses de administración de linagliptina en pacientes con IG disminuyó la glucosa a los 90 y 120 minutos después de una carga oral de dextrosa de 75-g y el ABC de la glucosa. La metformina disminuyó la insulina en 0 minutos.

Inhibition of the sodium-glucose co-transporter 2 in the elderly: clinical and mechanistic insights into safety and efficacy

SUMMARY The prevalence of type 2 diabetes mellitus (T2DM) in the elderly grew sharply over the last decade. Reduced insulin sensitivity and secretory capacity, weight gain, sarcopenia, and elevated adiposity are all common metabolic and body changes in the aging population that favor an increased risk of hypoglycemia, frailty syndrome, falls, and cognitive dysfunction. First line antidiabetic therapy is frequently not safe in older individuals because of its high risk of hypoglycemia and prevalent co-morbid diseases, such as chronic kidney disease, osteoporosis, cardiovascular disease, and obesity. Sodium-glucose cotransporter 2 inhibitor (SGLT2i) is a new class of antidiabetic therapy that inhibits glucose and sodium reabsorption on renal proximal convoluted tubule. Its effect is well demonstrated in various clinical scenarios in the younger population. This review and metanalysis describe particularities of the SGLT2i on the elderly, with mechanistic insights of the potential benefit and remaining challenges about the use of these drugs in this important age group. Further, we will present a meta-analysis of the main effects of SGLT2i reported in post-hoc studies in which the median age of the subgroups analyzed was over 60 years. Despite the absence of specific clinical trials for this population, our findings suggest that SGLT2i therapy on older individuals is effective to lower glucose and maintain its effect on systolic blood pressure and body weight.

RESUMO A prevalência da diabetes mellitus tipo 2 em idosos cresceu muito na última década. A redução na sensibilidade à insulina e na capacidade secretora, ganho de peso, sarcopenia e adiposidade elevada são todas alterações metabólicas e corporais comuns entre a população idosa. Essas mudanças críticas favorecem o aumento no risco de hipoglicemia, síndrome de fragilidade, quedas e disfunções cognitivas. A primeira linha de tratamento contra a diabete muitas vezes não é segura para indivíduos mais velhos devido ao alto risco de hipoglicemia e a prevalência de comorbidades patogênicas, como doença renal crônica, osteoporose, doença cardiovascular e obesidade. Os inibidores do cotransportador sódio-glicose 2 (SGLT2) são uma nova classe de tratamento contra a diabete que inibe reabsorção de glicose e sódio na parte convoluta do túbulo proximal. Seu efeito é claramente demonstrado em diversos cenários clínicos em populações mais jovens. Esta revisão e meta-análise descreve as particularidades dos SGLT2 na população idosa, abordando os mecanismos dos potenciais benefícios e desafios ainda presentes do uso destes medicamentos nesse grupo etário tão importante. Além disso, apresentaremos uma meta-análise dos principais efeitos dos SGLT2 encontrados em estudos post-hoc nos quais a idade média dos subgrupos analisados foi acima de 60 anos. Apesar da ausência de ensaios clínicos que incluem essa população, os dados encontrados sugerem que o tratamento com SGLT2 em idosos é eficaz para diminuir os níveis de glicose e tem efeitos na pressão arterial sistólica e no peso corporal.

Efeitos da suplementação de ômega 3 na resistência à insulina em mulheres com síndrome do ovário policístico: revisão sistemática / Effects of omega 3 supplementation on insulin resistance in women with polycystic ovary syndrome: systematic review

Introdução: A síndrome do ovário policístico (SOP) é uma disfunção hormonal que acomete mulheres em idade reprodutiva podendo causar infertilidade, alterações no ciclo menstrual, hirsutismo, presença de cistos nos ovários, amenorreia e distúrbios metabólicos. Dentre as alterações metabólicas, resistência à insulina (RI) está presente em 70,5% das brasileiras com SOP. Objetivo: Revisar sistematicamente a literatura para descrever os efeitos da suplementação de ômega-3 na RI em mulheres com SOP. Materiais e métodos: As buscas pela informação foram realizadas na base de dados PubMed e LILACS utilizando os descritores "síndrome do ovário policístico"; "ácidos graxos ômega-3" e "resistência à insulina", em português e inglês. Resultados: Foram encontrados sessenta estudos e após o crivo metodológico seis foram selecionados para compor esta revisão. Ao total dos ensaios clínicos incluídos nesta revisão, 326 mulheres com faixa etária correspondente a 18-45 anos foram avaliadas com variações de índice de massa corporal entre 25 e 45 kg/m2. A variação de tempo de acompanhamento entre os estudos foi de 2 a 6 meses. Discussão: Em todos os estudos incluídos nesta revisão, a homeostase da glicose sérica foi avaliada pelo índice HOMA. Apenas 1 estudo avaliou o índice quantitativo de verificação da sensibilidade à insulina (QUICK1); 2 estudos avaliaram hemoglobina glicada e índice de sensibilidade à insulina (ISI de Matsuda). A avaliação da insulinemia de jejum foi realizada em 4 estudos. Metade dos estudos incluídos suplementou os pacientes com 1.000 mg de ômega-3 ao dia, enquanto 25% dos estudos utilizou a dosagem de 2000 mg/dia 25% utilizou 4000 mg/dia. A maioria das pesquisas encontradas (67%) descreveu efeito positivo entre a suplementação de ômega-3 e melhora da RI de mulheres com SOP, utilizando os diferentes métodos de dosagem da homeostase da glicose sérica. Conclusão: Conclui-se que o consumo de ômega-3 pode ter efeito positivo sobre a RI.

Introduction: Polycystic ovarian syndrome (PCOS) is a hormonal dysfunction that affects women of childbearing age and can cause infertility, changes in the menstrual cycle, hirsutism, ovarian cysts, amenorrhea, and metabolic disorders. Among the metabolic changes insulin resistance (IR) is present in 70.5% of Brazilians with PCOS. Objective:To systematically review the literature to describe the effects of omega-3 supplementation on IR in women with PCOS. Materials and methods: Information searches were performed in the PubMed and LILACS database using the descriptors "polycystic ovarian syndrome"; "fatty acids omega-3" and "insulin resistance", in Portuguese and English. Results: Sixty studies were found and six were selected to compose this review. In the total of the clinical trials included in this review, 326 women aged 18-45 years were evaluated with variations in body mass index between 25 and 45 kg/m2. The variation in follow-up time between the studies was from 2 to 6 months. Discussion: In all studies included in this review, serum glucose homeostasis was assessed by the HOMA index. Only 1 study evaluated the quantitative index of insulin sensitivity (QUICK1); 2 studies evaluated glycated hemoglobin and insulin sensitivity index (Matsuda ISI). The evaluation of fasting insulinemia was performed in 4 studies. Half of the included studies supplemented patients with 1000 mg omega-3 daily, while 25% of the studies used the dosage of 2000 mg / day 25% used 4000 mg / day. Most of the researches (67%) described a positive effect between omega-3 supplementation and improvement of IR in women with PCOS, using the different dosing methods for serum glucose homeostasis. Conclusion: It is concluded that omega-3 consumption may have a positive effect on IR.

Efectos de la ingesta de los edulcorantes estevia y D-tagatosa sobre el metabolismo de la glucosa, ácido úrico y apetito-saciedad / Effects of stevia and D-tagatose sweeteners intake om glucose, uric acid metabolism and appetite-satiety

INTRODUCCIÓN: Si bien, los edulcorantes no nutritivos (ENN) estevia y D-tagatosa han sido reportados como seguros, han demostrado tener algunos efectos metabólicos tras su ingesta. OBJETIVO: Describir los efectos de la ingesta de estevia y D-tagatosa sobre el metabolismo de la glucosa y ácido úrico, y del apetito-saciedad, a partir de la evidencia disponible. MÉTODOS: Revisión descriptiva. Se realizó búsqueda en PubMed utilizando los siguientes términos y palabras clave: "stevia rebaudiana", "tagatose", "D-tagatose", "blood glucose", "insulin", "metabolic processes", "uric acid", "hyperuricemia", "appetite" o "satiety". El análisis de los estudios seleccionados fue discrecional. RESULTADOS: Existen estudios que demuestran efectos beneficiosos tras el consumo de estevia o D-tagatosa sobre el control glicémico, apetito y saciedad tanto en sujetos sanos como con alteraciones en el metabolismo de la glucosa. Por otra parte, un número importante de estudios que evalúan la ingesta de estevia reportan efectos nulos sobre dichos parámetros. En relación al ácido úrico, solo un estudio en sujetos con enfermedad renal crónica reporta aumento en la concentración de ácido úrico plasmático tras la ingesta de 500 mg/día de estevia. Pocos estudios han evaluado el efecto de la ingesta de D-tagatosa sobre uricemia, en sujetos sanos y diabéticos, reportando un aumento transitorio y significativo en los niveles de ácido úrico sérico, sin embargo, no se ha logrado demostrar un efecto hiperuricémico asociado. Es importante destacar que la metodología de los estudios revisados es heterogénea, especialmente en relación al tamaño muestral, tiempo, dosis y vía de adminitración del edulcorante. CONCLUSIÓN: La ingesta de estevia y D-tagatosa ha demostrado efectos beneficiosos sobre el metabolismo de la glucosa, el apetito y la saciedad. El efecto del consumo de D-tagatosa sobre ácido úrico sérico requiere mayor evidencia para demostrar su significancia clínica.

INTRODUCTION: No-nutritive sweeteners stevia and D-tagatose have been reported as safe according to their acceptable daily intake, however, they have been shown to have metabolic effects after their ingestion. OBJECTIVE: To describe the effects of stevia and D-tagatose intake on parameters associated to glucose, uric acid metabolism and on appetite-satiety, considering the available evidence. METHODS: Descriptive review. PubMed search was carried out to identify the totality of the published articles. The following terms and key words were used: "stevia rebaudiana", "tagatose", "D-tagatose", "blood glucose", "insulin", "metabolic processes", "uric acid", "hyperuricemia", "appetite" o "satiety". The analysis of the selected studies was discretionary. RESULTS: studies have shown beneficial effects of stevia and D-tagatose consumption on glycemic control, appetite and satiety in healthy subjects as well as subjects with impairment glucose metabolism. On the other hand, a significant number of studies evaluating estevia intake report null effects on these parameters. In relation to uric acid, only one study in subjects with chronic kidney disease reported an increase in plasmatic uric acid concentration after the intake of 500 mg/day of stevia. Several studies have evaluated the effect of D-tagatose intake on plasmatic uric acid, in healthy and diabetic subjects, reporting a transient and significant increase in serum uric acid levels, however, has not been able to demonstrate an associated hyperuricemic effect. It is important to highlight that the methodology of the studies reviewed is heterogeneous, especially in relation to sample size, dose administered, time and route of exposure to the sweetener. CONCLUSION: Stevia and D-tagatose intake has shown beneficial effects on glucose metabolism, appetite and satiety. The effects of the consumption of both sweeteners on uric acid require further study to demonstrate their clinic significance.

Forma activa de la vitamina D en pacientes pediátricos con sobrepeso y obesidad en el noroeste de México / Active form of vitamin D in overweight and obese pediatric patients in northwest Mexico

Resumen: Introducción: Los niveles bajos de vitamina D se han asociado con una gama de condiciones clínicas como obesidad, resistencia a la insulina y diabetes mellitus. Existen pocos estudios donde se hayan realizado mediciones de la forma activa de la vitamina D (1,25 (OH)2 vitamina D) en niños con obesidad. Sin embargo, los datos publicados no son concluyentes. El objetivo de este estudio fue determinar los niveles de la forma activa de la vitamina D en niños con obesidad y sobrepeso y determinar la asociación entre los niveles bajos de esta vitamina, la obesidad y las alteraciones del metabolismo de la glucosa. Métodos: Estudio transversal analítico en niños de 6 a 12 años de edad con exceso de adiposidad determinado por el índice cintura-estatura y el índice Z de masa corporal. Se midieron niveles de glucosa, insulina, perfil de lípidos completo, modelo homeostático para evaluar la resistencia a la insulina y la forma activa de la vitamina D. Se consideraron como niveles bajos de vitamina D aquellos menores a 30 pg/ml. Resultados: La prevalencia de niveles bajos de la forma activa de la vitamina D fue del 36%. La asociación entre niveles bajos de la forma activa de la vitamina D y niveles altos de insulina resultó estadísticamente significativa. No se encontró asociación significativa entre los niveles de la vitamina y las medidas de adiposidad. Conclusiones: Se encontraron niveles bajos de la forma activa de la vitamina D en el 36% de la población estudiada, y se demostró su asociación con la resistencia a insulina e hiperinsulinemia.

Abstract: Background: Low levels of vitamin D have been associated with a range of clinical conditions such as obesity, insulin resistance, and diabetes mellitus, among others. There are few studies that measure the active form of vitamin D (1,25 (OH)2 vitamin D) in obese children. However, published data are inconclusive. The aim of this study was to determine the active levels of vitamin D in obese and overweight children and to find an association between low levels of vitamin D, obesity and impaired glucose metabolism. Methods: A cross-sectional, analytical study was conducted in 6 to 12-year-old children with excess adiposity determined by waist-stature index and body mass index. Levels of glucose, insulin, complete lipid profile, homeostatic model assessment and the active form of vitamin D were measured in each patient. Levels < 30 pg/ml were considered as low levels of vitamin D. Results: The prevalence of low levels of active vitamin D was 36%. A significant association between low levels of active vitamin D and high levels of insulin was found. No significant association was found between vitamin levels and adiposity measures. Conclusions: Low levels of active vitamin D were found in 36% of the population studied. A significant association with insulin resistance and hyperinsulinemia was demonstrated.

El esqueleto como órgano endocrino: funciones metabólicas de la osteocalcina / The skeleton as an endocrine organ: metabolic functions of osteocalcin

El esqueleto es uno de los sistemas más grandes de un vertebrado y, como tal, es razonable especular que no puede funcionar aislado del resto del organismo. De hecho, sabemos que existen sistemas complejos de regulación cruzada entre el esqueleto y muchos otros órganos. Hoy poseemos herramientas que nos permiten realizar supresión genética en células o tejidos específicos. Esto nos ha permitido comprender cómo los órganos se comunican entre sí y ha revitalizado el concepto de fisiología del organismo como un todo. Efectivamente, los últimos años han sido testigos del descubrimiento de funciones inesperadas que ejerce el esqueleto y que afectan al organismo en su totalidad. Una de tales funciones reconocidas recientemente es el control del metabolismo energético, a través de la secreción de osteocalcina. La osteocalcina es una hormona producida por los osteoblastos que regula la secreción de insulina, la sensibilidad a esta hormona y el metabolismo energético. Los hallazgos iniciales suscitaron varias preguntas fundamentales sobre la naturaleza de la acción de la insulina sobre el hueso. Pero esto solo fue la punta del iceberg. Efectivamente, más adelante se descubrió, mediante el análisis de ratones que carecen del receptor de insulina (Ins R) solamente en osteoblastos, que la acción de la insulina sobre estas células favorecía la homeostasis de la glucosa en todo el cuerpo. Es importante destacar que esta función de la insulina en los osteoblastos opera mediante la regulación negativa de la carboxilación y la biodisponibilidad de la osteocalcina. Más aún, se observó que las vías de señalización de la insulina en los osteoblastos regulan positivamente no solo la formación sino también la resorción del hueso. Curiosamente, parece que las vías de señalización de la insulina en osteoblastos pueden inducir la activación de la osteocalcina mediante la estimulación de la actividad de los osteoclastos. De hecho, el bajo pH generado durante la resorción ósea es suficiente para desencadenar la descarboxilación (y subsiguiente activación) de la osteocalcina. En breve discutiremos dos nuevas proposiciones: 1) los osteoblastos son un blanco utilizado por la insulina para controlar la homeostasis de la glucosa en todo el organismo y 2) la resorción ósea desempeña un papel fundamental en la regulación de la activación de la osteocalcina. (AU)

The skeleton is one of the biggest systems in a vertebrate animal and, as such, it is reasonable to speculate that it cannot function isolated from the rest of the organism. In fact, we know that complex systems exist for the cross-regulation between the skeleton and several other organs. Today, we have the tools that allow us to perform genetic suppression in specific cells or tissues. This has allow us understand the mechanisms by which the organs communicate with each other and has revitalized the concept of organismal physiology as a whole. Studies conducted in recent years have uncovered unexpected functions performed by the skeleton. One of these is the control of global energy metabolism, through the secretion of osteocalcin, a protein produced by osteoblasts that acts as a hormone regulating insulin secretion, insulin sensitivity and energy expenditure. The evidence comes from the analysis of mice lacking insulin receptor (InsR) exclusively in osteoblasts. These mice have a global metabolic phenotype demonstrating that the action of insulin in osteoblasts promotes the homeostasis of glucose throughout the body. This action of insulin in osteoblasts is mediated by the negative regulation of the carboxylation (and bioavailability) of osteocalcin. The decarboxylation (and activation) of osteocalcin, in turn, occurs in the osteoclastic resorption pit. Briefly: the osteoblast is a target used by insulin to control the homeostasis of glucose throughout the body and bone resorption is the mechanism that regulates the activation of osteocalcin. (AU)

Prevalence of pancreatic autoantibodies in non-diabetic patients with autoimmune thyroid disease and its relation to insulin secretion and glucose tolerance

ABSTRACT Objective We evaluated the prevalence of glutamic acid decarboxylase (GADA) and tyrosine phosphatase-protein antibodies (IA2A), their titers and their relation to first phase insulin response (FPIR) and glucose tolerance in autoimmune thyroid diseases (ATDs) patients. Subjects and methods Graves' disease (GD; n = 181) and Hashimoto's thyroiditis (HT; n = 143) patients in addition to healthy controls (n = 93) were studied. Secondly, FPIR and oral glucose tolerance tests (OGTT) were performed in 11 anti-pancreatic islet-cell (+) and in 20 anti-pancreatic-cell (-) patients. Results There was a non significant trend for higher prevalence of GADA positivity in GD vs HT (7.2% vs 2% p = 0.06), but the GADA titers were higher in HT. We also did not find a significant difference in IA2 prevalence (0.7% vs 0.0%) between these two groups or compared to the control group. In the subsequent analysis, low FPIR was found in 10% of these patients but without statistical difference for OGTT between pancreatic antibody-positive and -negative patients. Conclusion A trend for greater prevalence of GADA was observed for GD patients than for HT or control. However, the titers of these autoantibodies were higher in HT patients, but there was no significant relation to insulin secretion and glucose tolerance at that moment and stage of autoimmune diseases.