Role of insulin in endogenous hypertriglyceridemia

Molecular regulators of exercise-mediated insulin sensitivity in non-obese individuals

Insulin resistance is a significant contributor to the development of type 2 diabetes (T2D) and is associated with obesity, physical inactivity, and low maximal oxygen uptake. While intense and prolonged exercise may have negative effects, physical activity can have a positive influence on cellular metabolism and the immune system. Moderate exercise has been shown to reduce oxidative stress and improve antioxidant status, whereas intense exercise can increase oxidative stress in the short term. The impact of exercise on pro-inflammatory cytokine production is complex and varies depending on intensity and duration. Exercise can also counteract the harmful effects of ageing and inflamm-ageing. This review aims to examine the molecular pathways altered by exercise in non-obese individuals at higher risk of developing T2D, including glucose utilization, lipid metabolism, mitochondrial function, inflammation and oxidative stress, with the potential to improve insulin sensitivity. The focus is on understanding the potential benefits of exercise for improving insulin sensitivity and providing insights for future targeted interventions before onset of disease.

A machine learning approach to personalized predictors of dyslipidemia: a cohort study

Introduction

Mexico ranks second in the global prevalence of obesity in the adult population, which increases the probability of developing dyslipidemia. Dyslipidemia is closely related to cardiovascular diseases, which are the leading cause of death in the country. Therefore, developing tools that facilitate the prediction of dyslipidemias is essential for prevention and early treatment.

Methods

In this study, we utilized a dataset from a Mexico City cohort consisting of 2,621 participants, men and women aged between 20 and 50 years, with and without some type of dyslipidemia. Our primary objective was to identify potential factors associated with different types of dyslipidemia in both men and women. Machine learning algorithms were employed to achieve this goal. To facilitate feature selection, we applied the Variable Importance Measures (VIM) of Random Forest (RF), XGBoost, and Gradient Boosting Machine (GBM). Additionally, to address class imbalance, we employed Synthetic Minority Over-sampling Technique (SMOTE) for dataset resampling. The dataset encompassed anthropometric measurements, biochemical tests, dietary intake, family health history, and other health parameters, including smoking habits, alcohol consumption, quality of sleep, and physical activity.

Results

Our results revealed that the VIM algorithm of RF yielded the most optimal subset of attributes, closely followed by GBM, achieving a balanced accuracy of up to 80%. The selection of the best subset of attributes was based on the comparative performance of classifiers, evaluated through balanced accuracy, sensitivity, and specificity metrics.

Discussion

The top five features contributing to an increased risk of various types of dyslipidemia were identified through the machine learning technique. These features include body mass index, elevated uric acid levels, age, sleep disorders, and anxiety. The findings of this study shed light on significant factors that play a role in dyslipidemia development, aiding in the early identification, prevention, and treatment of this condition.

Prognostic value of triglyceride/glucose index in patients with ST-segment elevation myocardial infarction

Aim: New parameters are emerging to predict prognosis in patients with ST-segment elevation myocardial infarction (STEMI). In this study we aimed to determine and compare the prognostic values of some metabolic indices in terms of predicting long-term mortality in patients with STEMI. Method: A total of 1900 nondiabetic patients who presented with STEMI and underwent percutaneous coronary intervention were included in the study. Multivariable Cox proportional regression analysis was used to determine and compare the predictive performance of triglyceride-glucose (TyG) index, triglyceride-high density lipoprotein ratio (Ty/HDL) and admission glucose. Results: In multivariable Cox regression analysis, the model based on TyG index had better predictive performance than the Ty/HDL and admission blood glucose. Conclusion: The TyG index is more informative than Ty/HDL and admission glucose level to predict long-term all-cause mortality.

Insulin resistance-related differences in the relationship between left ventricular hypertrophy and cardiorespiratory fitness in hypertensive Black sub-Saharan Africans

BACKGROUND

Left ventricular hypertrophy (LVH) is associated with impaired cardiorespiratory fitness (CRF), a surrogate marker of poor outcome. Insulin resistance (IR) plays a central role in all stages of cardiovascular disease continuum. This study evaluates IR-related differences in the relationship between left ventricular mass (LVM) and CRF in asymptomatic newly diagnosed hypertensive Black sub-Saharan Africans.

METHODS

In this cross-sectional observational study, 126 asymptomatic newly diagnosed hypertensive participants (50.5 ± 9.5 years) underwent comprehensive resting transthoracic echocardiographic examination and maximal incremental cardiopulmonary exercise test (CPET). CRF was estimated in maximal oxygen uptake (VO2max). CPET results were compared between participants with and without LVH. Multivariate analysis examined the influence of IR on the observed differences.

RESULTS

Those with LVH had lower VO2max (15.7 ± 5.5 mL min^-1 kg^-1 vs. 18.4 ± 3.7 mL min^-1 kg^-1; P = 0.001) than those without LVH. In patients with IR, LVM (r = -0.261, P = 0.012), LVM indexed to body surface area (LVMIbsa; r = -0.229, P = 0.027), and LVM indexed to height to an allometric power of 2.7 (LVMIh^2.7; r = -0.351, P = 0.001), and VO2max were negatively correlated. In hypertensive patients without IR, these same parameters and VO2max have no significant correlation. Body mass index (BMI), LVM, and LVMIbsa emerged as independent determinants of VO2max, explaining 46.9% of its variability (overall P = 0.001) in IR participants, a relationship not found in participants without IR.

CONCLUSIONS

IR may participate in the deterioration of CRF associated with LVH. Measures to improve insulin sensitivity should be considered for improving CRF and therefore the prognosis of insulin-resistant hypertensive patients. Targeting IR in hypertensive patients with LVH could improve prognosis.

Dyslipidemia, insulin resistance, and impairment of placental metabolism in the offspring of obese mothers

Obesity is a chronic condition associated with dyslipidemia and insulin resistance. Here, we show that the offspring of obese mothers are dyslipidemic and insulin resistant from the outset.Maternal and cord blood and placental tissues were collected following C-section at term. Patients were grouped as being normal weight (NW, BMI = 18-24.9) or obese (OB, BMI ≥ 30), and separated by fetal sex. We measured plasma lipids, insulin, and glucose in maternal and cord blood. Insulin resistance was quantified using the HOMA-IR. Placental markers of lipid and energy metabolism and relevant metabolites were measured by western blot and metabolomics, respectively.For OB women, total cholesterol was decreased in both maternal and cord blood, while HDL was decreased only in cord blood, independent of sex. In babies born to OB women, cord blood insulin and insulin resistance were increased. Placental protein expression of the energy and lipid metabolism regulators PGC1α, and SIRT3, ERRα, CPT1α, and CPT2 decreased with maternal obesity in a sex-dependent manner (P < 0.05). Metabolomics showed lower levels of acylcarnitines C16:0, C18:2, and C20:4 in OB women's placentas, suggesting a decrease in β-oxidation. Glutamine, glutamate, alpha-ketoglutarate (αKG), and 2-hydroxyglutarate (2-HG) were increased, and the glutamine-to-glutamate ratio decreased (P < 0.05), in OB placentas, suggesting induction of glutamate into αKG conversion to maintain a normal metabolic flux.Newly-born offspring of obese mothers begin their lives dyslipidemic and insulin resistant. If not inherited genetically, such major metabolic perturbations might be explained by abnormal placental metabolism with potential long-term adverse consequences for the offspring's health and wellbeing.

Association between insulin resistance and left ventricular hypertrophy in asymptomatic, Black, sub-Saharan African, hypertensive patients: a case-control study

Background

Conflicting information exists regarding the association between insulin resistance (IR) and left ventricular hypertrophy (LVH). We described the associations between obesity, fasting insulinemia, homeostasis model assessment of insulin resistance (HOMA-IR), and LVH in Black patients with essential hypertension.

Methods

A case–control study was conducted at the Centre Médical de Kinshasa (CMK), the Democratic Republic of the Congo, between January and December 2019. Cases and controls were hypertensive patients with and without LVH, respectively. The relationships between obesity indices, physical inactivity, glucose metabolism and lipid disorder parameters, and LVH were assessed using linear and logistic regression analyses in simple and univariate exploratory analyses, respectively. When differences were observed between LVH and independent variables, the effects of potential confounders were studied through the use of multiple linear regression and in conditional logistic regression in multivariate analyses. The coefficients of determination (R²), adjusted odds ratios (aORs), and their 95% confidence intervals (95% CIs) were calculated to determine associations between LVH and the independent variables.

Results

Eighty-eight LVH cases (52 men) were compared against 132 controls (81 men). Variation in left ventricular mass (LVM) could be predicted by the following variables: age (19%), duration of hypertension (31.3%), body mass index (BMI, 44.4%), waist circumference (WC, 42.5%), glycemia (20%), insulinemia (44.8%), and HOMA-IR (43.7%). Hypertension duration, BMI, insulinemia, and HOMA-IR explained 68.3% of LVM variability in the multiple linear regression analysis. In the logistic regression model, obesity increased the risk of LVH by threefold [aOR 2.8; 95% CI (1.06–7.4); p = 0.038], and IR increased the risk of LVH by eightfold [aOR 8.4; 95 (3.7–15.7); p < 0.001].

Conclusion

Obesity and IR appear to be the primary predictors of LVH in Black sub-Saharan African hypertensive patients. The comprehensive management of cardiovascular risk factors should be emphasized, with particular attention paid to obesity and IR. A prospective population-based study of Black sub-Saharan individuals that includes the use of serial imaging remains essential to better understand subclinical LV deterioration over time and to confirm the role played by IR in Black sub-Saharan individuals with hypertension.

Effects of cardamom supplementation on lipid profile: A systematic review and meta-analysis of randomized controlled clinical trials

Cardiovascular disease is a highly prevalent issue worldwide and one of its main manifestations, dyslipidemia, needs more attention. Recent studies have suggested that cardamom has favorable effects beyond lipid lowering, but the result are contradictory. Our objective was to conduct a systematic review and meta-analysis on randomized controlled trials (RCTs) that assessed the effect of cardamom on lipids. The search included PubMed, Scopus, ISI Web of Science, Google Scholar, and the Cochrane library (up to March, 2019) to identify RCTs investigating the effects of cardamom supplementation on serum lipid parameters. Weighted mean differences (WMDs) were pooled using a random-effect model. Meta-analysis of data from five eligible RCTs showed that cardamom supplementation did not significantly change the concentrations of total cholesterol (WMD: -6.11 mg/dl, 95% CI [-13.06, 0.83], I² = 0.0%), low-density lipoprotein cholesterol (WMD: -4.31 mg/dl, 95% CI [-9.75, 1.13], I² = 0.0%), or high-density lipoprotein cholesterol (WMD: 1.75 mg/dl, 95% CI [-1.95 to 5.46], I² = 71.4%). However, a significant reduction was observed in serum triglyceride (TG; WMD: -20.55 mg/dl, 95% CI [-32.48, -8.63], I² = 0.0%) levels after cardamom supplementation. Cardamom might be able to change TG, but for confirming the results, more studies exclusively on dyslipidemia patients and considering the intake of lipid lowering agents as exclusion criteria are necessary.

Beneficial effects of green cardamom on serum SIRT1, glycemic indices and triglyceride levels in patients with type 2 diabetes mellitus: a randomized double-blind placebo controlled clinical trial

BACKGROUND

Cardamom has antioxidant and anti-inflammatory effects which may help to remedy diseases. Studies on the health benefits of cardamom in diabetic patients are very limited. Thus, this study is designed to determine the effect of cardamom supplementation on blood lipids and glycemic indices in type 2 diabetic patients. To investigate the mechanism of cardamom effect on blood glucose and lipid levels, serum sirtuin-1 (SIRT1) was assessed.

RESULTS

In a parallel, double-blind randomized, placebo-controlled clinical trial, 83 overweight or obese type 2 diabetic patients were randomly allocated into an intervention (n = 41) or a control group (n = 42). The intervention and the placebo group received 3 g of green cardamom or rusk powder, respectively for 10 weeks. Physical activity level, dietary intake, anthropometric measurements (weight, height and waist circumference), glycemic indices [glucose, insulin, hemoglobin A1c (HbA1c)], blood lipids [triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-c) and low-density lipoprotein cholesterol (LDL-c)] and SIRT1 levels were measured. Body mass index and homeostasis model assessment as an index of insulin resistance (HOMA-IR) were calculated before and after intervention. Compared to the control group, a significant decrease in serum HbA1C (-0.4%), insulin (-2.8 µIU dL^-1 ), HOMA-IR (-1.7) and TG (-39.9 mg dL^-1 ), and an increase in SIRT1 (2.3 ng mL^-1 ) was observed in cardamom group. There were no significant changes in serum TC, HDL-c and LDL-c levels between the two groups before and after adjustment for potential confounders including glyclaside dose, duration of disease and weight.

CONCLUSION

Our results showed that cardamom can decrease HbA1c, insulin level, HOMA-IR and TG level via increase in SIRT1 concentration in type 2 diabetes mellitus patients. © 2019 Society of Chemical Industry.

Bariatric surgery as a model to explore the basis and consequences of the Reaven hypothesis: Small, dense low-density lipoprotein and interleukin-6

BACKGROUND

Reaven originally described the clustering of insulin resistance/hyperinsulinaemia, obesity (particularly visceral), altered cytokine levels, glucose intolerance, hypertriglyceridaemia and low high-density lipoprotein cholesterol. Subsequently, a potentially highly atherogenic small, dense low-density lipoprotein was also reported. We have studied the effect of bariatric surgery on this and other risk factors for atherosclerosis.

METHODS

Forty patients (20 with type 2 diabetes mellitus) undergoing bariatric surgery were studied before and 1 year after bariatric surgery.

RESULTS

Twelve months after bariatric surgery, median body mass index had decreased from 49.5 to 36.5 kg/m², fasting insulin from 21.3 to 7.8 mU/L and insulin resistance (homeostatic model assessment of insulin resistance) from 5.9 to 1.8 (all p < 0.001). Thirteen out of 20 patients had remission from type 2 diabetes mellitus. Highly sensitive C-reactive protein, interleukin-6, fasting triglycerides ( p < 0.001) and small, dense low-density lipoprotein ( p < 0.001) decreased, while high-density lipoprotein cholesterol increased ( p < 0.001) significantly, irrespective of having type 2 diabetes mellitus and/or being treated with statin therapy before surgery.

CONCLUSION

The association between marked weight loss and change in insulin resistance and hyperinsulinaemia with the change in small, dense low-density lipoprotein and interleukin-6 warrants further investigation. Bariatric surgery provides a model for investigating the mechanisms linking insulin resistance/hyperinsulinaemia to atherosclerosis.

Impact of race/ethnicity on insulin resistance and hypertriglyceridaemia

OBJECTIVE

Insulin sensitivity affects plasma triglyceride concentration and both differ by race/ethnicity. The purpose of this study was to provide a comprehensive assessment of the variation in insulin sensitivity and its relationship to hypertriglyceridaemia between five race/ethnic groups.

RESEARCH DESIGN AND METHODS

In this cross-sectional study, clinical data for 1025 healthy non-Hispanic White, Hispanic White, East Asian, South Asian and African American individuals were analysed. Insulin-mediated glucose disposal (a direct measure of peripheral insulin sensitivity) was measured using the modified insulin suppression test. Statistical analysis was performed using analysis of co-variance.

RESULTS

Of the study participants, 63% were non-Hispanic White, 9% were Hispanic White, 11% were East Asian, 11% were South Asian and 6% were African American. Overall, non-Hispanic Whites and African Americans displayed greater insulin sensitivity than East Asians and South Asians. Triglyceride concentration was positively associated with insulin resistance in all groups, including African Americans. Nevertheless, for any given level of insulin sensitivity, African Americans had the lowest triglyceride concentrations.

CONCLUSION

Insulin sensitivity, as assessed by a direct measure of insulin-mediated glucose disposal, and its relationship to triglyceride concentration vary across five race/ethnic groups. Understanding these relationships is crucial for accurate cardiovascular risk stratification and prevention.

The Impact of Insulin Resistance and Chronic Kidney Disease on Inflammation and Cardiovascular Disease

There is extensive evidence showing that insulin resistance (IR) is associated with chronic low-grade inflammation. Furthermore, IR has been shown to increase the risk for cardiovascular disease (CVD), even in nondiabetic patients, and is currently considered as a “nontraditional” risk factor contributing to CVD by promoting hypertension, oxidative stress, endothelial dysfunction, dyslipidemia, and type 2 diabetes mellitus. However, chronic kidney disease (CKD) is also considered a state of low-grade inflammation. In addition, CKD is considered an IR state and has been described as an independent risk factor for the development of CVD, as even early-stage CKD is associated with an estimated 40% to 100% increase in CVD risk. There is also strong evidence indicating that inflammation per se plays a crucial role in both the initiation and progression of CVD. Given the above, the combined effect of IR and CKD may significantly increase the risk of inflammation and CVD. This review aims to focus on the complex interplay between IR, CKD, inflammation, and CVD and will present and discuss the current clinical and scientific data pertaining to the impact of IR and CKD on inflammation and CVD.

Adipose morphology and metabolic disease

Adipose morphology is defined as the number and size distribution of adipocytes (fat cells) within adipose tissue. Adipose tissue with fewer but larger adipocytes is said to have a 'hypertrophic' morphology, whereas adipose with many adipocytes of a smaller size is said to have a 'hyperplastic' morphology. Hypertrophic adipose morphology is positively associated with insulin resistance, diabetes and cardiovascular disease. By contrast, hyperplastic morphology is associated with improved metabolic parameters. These phenotypic associations suggest that adipose morphology influences risk of cardiometabolic disease. Intriguingly, monozygotic twin studies have determined that adipose morphology is in part determined genetically. Therefore, identifying the genetic regulation of adipose morphology may help us to predict, prevent and ameliorate insulin resistance and associated metabolic diseases. Here, we review the current literature regarding adipose morphology in relation to: (1) metabolic and medical implications; (2) the methods used to assess adipose morphology; and (3) transcriptional differences between morphologies. We further highlight three mechanisms that have been hypothesized to promote adipocyte hypertrophy and thus to regulate adipose morphology.

Temperature as a Circadian Marker in Older Human Subjects: Relationship to Metabolic Syndrome and Diabetes

Background:

Circadian rhythms are characterized by approximate 24-hour oscillations in physiological and behavioral processes. Disruptions in these endogenous rhythms, most commonly associated with shift work and/or lifestyle, are recognized to be detrimental to health. Several studies have demonstrated a high correlation between disrupted circadian rhythms and metabolic disease. The aim of this study was to determine which metabolic parameters correlate with physiological measures of circadian temperature amplitude (TempAmp) and stability (TempStab).

Methods:

Wrist skin temperature was measured in 34 subjects (ages 50 to 70, including lean, obese, and diabetic subjects) every 10 minutes for 7 consecutive days. Anthropometric measures and fasting blood draws were conducted to obtain data on metabolic parameters: body mass index, hemoglobin A1C, triglycerides, cholesterol, high-density lipoprotein, and low-density lipoprotein. A history of hypertension and current blood pressure was noted.

Results:

Analysis of the data indicated a substantial reduction in TempAmp and TempStab in subjects with metabolic syndrome (three or more risk factors). To determine the impact of individual interdependent metabolic factors on temperature rhythms, stepwise multilinear regression analysis was conducted using metabolic syndrome measurements. Interestingly, only triglyceride level was consistently correlated by the analysis. Triglyceride level was shown to contribute to 33% of the variability in TempAmp and 23% of the variability in TempStab.

Conclusion:

Our results demonstrate that elevated triglycerides are associated with diminished TempAmp and TempStab in human subjects, and triglycerides may serve as a primary metabolic predictor of circadian parameters.

A cellular model to study drug-induced liver injury in nonalcoholic fatty liver disease: Application to acetaminophen

Obesity and nonalcoholic fatty liver disease (NAFLD) can increase susceptibility to hepatotoxicity induced by some xenobiotics including drugs, but the involved mechanisms are poorly understood. For acetaminophen (APAP), a role of hepatic cytochrome P450 2E1 (CYP2E1) is suspected since the activity of this enzyme is consistently enhanced during NAFLD. The first aim of our study was to set up a cellular model of NAFLD characterized not only by triglyceride accumulation but also by higher CYP2E1 activity. To this end, human HepaRG cells were incubated for one week with stearic acid or oleic acid, in the presence of different concentrations of insulin. Although cellular triglycerides and the expression of lipid-responsive genes were similar with both fatty acids, CYP2E1 activity was significantly increased only by stearic acid. CYP2E1 activity was reduced by insulin and this effect was reproduced in cultured primary human hepatocytes. Next, APAP cytotoxicity was assessed in HepaRG cells with or without lipid accretion and CYP2E1 induction. Experiments with a large range of APAP concentrations showed that the loss of ATP and glutathione was almost always greater in the presence of stearic acid. In cells pretreated with the CYP2E1 inhibitor chlormethiazole, recovery of ATP was significantly higher in the presence of stearate with low (2.5mM) or high (20mM) concentrations of APAP. Levels of APAP-glucuronide were significantly enhanced by insulin. Hence, HepaRG cells can be used as a valuable model of NAFLD to unveil important metabolic and hormonal factors which can increase susceptibility to drug-induced hepatotoxicity.

Effects of High Fat Feeding on Adipose Tissue Gene Expression in Diabetic Goto-Kakizaki Rats

Development and progression of type 2 diabetes is a complex interaction between genetics and environmental influences. High dietary fat is one environmental factor that is conducive to the development of insulin-resistant diabetes. In the present report, we compare the responses of lean poly-genic, diabetic Goto-Kakizaki (GK) rats to those of control Wistar-Kyoto (WKY) rats fed a high fat diet from weaning to 20 weeks of age. This comparison included a wide array of physiological measurements along with gene expression profiling of abdominal adipose tissue using Affymetrix gene array chips. Animals of both strains fed a high fat diet or a normal diet were sacrificed at 4, 8, 12, 16, and 20 weeks for this comparison. The microarray analysis revealed that the two strains developed different adaptations to increased dietary fat. WKY rats decrease fatty acid synthesis and lipogenic processes whereas GK rats increase lipid elimination. However, on both diets the major differences between the two strains remained essentially the same. Specifically relative to the WKY strain, the GK strain showed lipoatrophy, chronic inflammation, and insulin resistance.

Hypertriglyceridemia in Infants and Children with Hypernatremia

BACKGROUND

Hypertriglyceridemia in association with hypernatremia was reported in a few children; however, studies exploring this association are limited.

OBJECTIVE

To determine the pattern of change in serum triglycerides levels in hypernatremia patients.

DESIGN AND SETTING

A prospective case-control study done at North West Armed Forces Hospital, Tabuk, Saudi Arabia from April 2008 to March 2011.

PATIENTS AND METHOD

serum triglycerides and sodium were measured in 16 patients with hypernatremic dehydration as a study group and 14 patients with isonatremic dehydration as a control group. The trend of serum sodium and triglycerides was followed during treatment in the study group.

RESULTS

There were 6 boys and 8 girls in the control group (isonatremic dehydration). Their age ranged between 4 months and five years (M±SD = 1.7±1.3 years). In the study group (hypernatremic dehydration), there were 6 boys and 10 girls. The age range was 2-14 months (M±SD = 0.6±0.4 years). The serum sodium and triglycerides (M±SD = 165.8±9.1 mmol/l, 5.1±8.1 mmol/l respectively) were significantly higher compared with the control group (M±SD = 137.5±3.9 mmol/l, 0.7±0.3 mmol/l and P < 0.001, P < 0.05 respectively). Duration of symptoms in patients with hypernatremic dehydration (M±SD = 2.9±2.4 days) were comparable to control group (M±SD = 2.0±0.9 days, P = 0.18). Four patients from the study group had normal serum triglycerides (M±SD = 1.1±0.1 mmol/l). With treatment, serum sodium was normalized in all patients followed by serum triglycerides.

CONCLUSION

Hypertriglyceridemia is present in most children with hypernatremia and it disappears when serum sodium returns to normal.

Plasma triglyceride determination can identify increased risk of statin-induced type 2 diabetes: a hypothesis

OBJECTIVE

To evaluate the ability of plasma triglyceride (TG) measurements to identify statin-treated persons at accentuated risk of statin-induced type 2 diabetes (T2DM).

METHODS

The experimental population consisted of nondiabetic, statin-treated patients (n = 469), classified as being at high risk for T2DM, subdivided on the basis of a plasma TG concentration of 1.7 mmol/L. Comparisons were made of demographic characteristics, concentrations of fasting glucose, insulin, HbA1c, and hs-CRP, oral glucose tolerance tests, estimates of insulin action and secretion, and lipid/lipoprotein profiles.

RESULTS

Despite similar fasting glucose and HbA1c concentrations, patients with elevated TG concentrations displayed markers of increased risk of T2DM (insulin resistance and compensatory hyperinsulinemia), more adverse lipid/lipoprotein profiles, and increased prevalence of abnormal hs-CRP values.

CONCLUSION

These findings demonstrate that plasma TG concentrations ≥ 1.7 mmol/L identified a subset of individuals at enhanced risk of developing statin-induced diabetes within a population classified prior to statin treatment as being at high risk of T2DM.

Effectiveness of chamomile tea on glycemic control and serum lipid profile in patients with type 2 diabetes

AIMS

This study aimed at assessing the effects of chamomile tea consumption on glycemic control and serum lipid profile in patients with type 2 diabetes mellitus (T2DM).

METHODS

This single-blind randomized controlled clinical trial was conducted on 64 individuals with T2DM (males and females) aged between 30 and 60 years. The intervention group (n = 32) consumed chamomile tea (3 g/150 mL hot water) three times per day immediately after meals for 8 weeks. The control group (n = 32) followed a water regimen for the same intervention period. Fasting blood samples, anthropometric measurements, and 3-day, 24-h dietary recalls were collected at the baseline and at the end of the trial. Data were analyzed by independent t test, paired t test, Pearson correlation test, and analysis of covariance.

RESULTS

Chamomile tea significantly decreased concentration of HbA1C (p = 0.03), serum insulin levels (p < 0.001), homeostatic model assessment for insulin resistance (p < 0.001), total cholesterol (p = 0.001), triglyceride (p < 0.001), and low-density lipoprotein cholesterol (p = 0.05) compared with control group. No significant changes were shown in serum high-density lipoprotein cholesterol levels in both groups.

CONCLUSION

Chamomile tea has some beneficial effects on glycemic control and serum lipid profile in T2DM patients.

Organophosphorus insecticide, monocrotophos, possesses the propensity to induce insulin resistance in rats on chronic exposure

BACKGROUND

Our earlier studies had shown that monocrotophos (MCP), an organophosphorus insecticide (OPI), has the propensity to augment the secondary complications associated with type-1 diabetes. The present study investigates whether rats exposed for prolonged periods to monocrotophos would develop insulin resistance mediated by alteration in glucose homeostasis.

METHODS

Male rats were administered sublethal doses of monocrotophos daily for 180 days. Interim blood samples were collected to measure alteration in blood glucose and lipid profile. Rats were also subjected to glucose and insulin tolerance test and fasting blood glucose and insulin levels were measured to calculate insulin resistance by HOMA-IR method. After 180 days, the rats were also evaluated for pancreatic histology and activities of hepatic gluconeogenetic enzymes.

RESULTS

Monocrotophos elicited a gradual and sustained increase in blood glucose and insulin resistance in rats with concomitant glucose intolerance and reduced insulin sensitivity. MCP exposure was also associated with increase in weights of key white adipose pads, activities of gluconeogenesis enzymes and increase in pancreatic islet diameter, all of which led to hyperglycemia, hyperinsulinemia and dyslipidaemia.

CONCLUSION

Long-term exposure of rats to MCP resulted in glucose intolerance with hyperinsulinemia, a hallmark of insulin resistance. Our data suggest that chronic exposure to low doses of monocrotophos, might lead to development of insulin resistance by altering lipid profile and glucose homeostasis.

High prevalence of insulin resistance assessed by the glucose clamp technique in hormonal and non-hormonal contraceptive users

OBJECTIVE

To assess the prevalence of insulin resistance (IR) and associated factors in contraceptive users.

METHODS

A total of 47 women 18 to 40 years of age with a body mass index (kg/m(2)) < 30, fasting glucose levels < 100 mg/dl and 2-hour glucose level < 140 mg/dl after a 75-g oral glucose load were submitted to a hyperinsulinemic-euglycemic clamp. The women were distributed in tertiles regarding M-values. The analysed variables were use of combined hormonal/non-hormonal contraception, duration of use, body composition, lipid profile, glucose levels and blood pressure.

RESULTS

IR was detected in 19% of the participants. The women with low M-values presented significantly higher body fat mass, waist-to-hip ratio, fasting insulin, HOMA-IR and were nulligravida, showed > 1 year of contraceptive use and higher triglyceride levels. IR was more frequent among combined oral contraceptive users, however no association was observed after regression analysis.

CONCLUSIONS

The prevalence of IR was high among healthy women attending a family planning clinic independent of the contraceptive method used with possible long-term negative consequences regarding their metabolic and cardiovascular health. Although an association between hormonal contraception and IR could not be found this needs further research. Family planning professionals should be proactive counselling healthy women about the importance of healthy habits.

Exercise and dietary-mediated reductions in postprandial lipemia

Postprandial hyperlipemia produces long-term derangements in lipid/lipoprotein metabolism, vascular endothelial dysfunction, hypercoagulability, and sympathetic hyperactivity which are strongly linked to atherogenesis. The purpose of this review is to (1) provide a qualitative analysis of the available literature examining the dysregulation of postprandial lipid metabolism in the presence of obesity, (2) inspect the role of adiposity distribution and sex on postprandial lipid metabolism, and (3) examine the role of energy deficit (exercise- and/or energy restriction-mediated), isoenergetic low-carbohydrate diets, and omega-3 (n-3) fatty acid supplementation on postprandial lipid metabolism. We conclude from the literature that central adiposity primarily accounts for sex-related differences in postprandial lipemia and that aerobic exercise attenuates this response in obese or lean men and women to a similar extent through potentially unique mechanisms. In contrast, energy restriction produces only mild reductions in postprandial lipemia suggesting that exercise may be superior to energy restriction alone as a strategy for lowering postprandial lipemia. However, isoenergetic very low-carbohydrate diets and n-3 fatty acid supplementation reduce postprandial lipemia indicating that macronutrient manipulations reduce postprandial lipemia in the absence of energy restriction. Therefore, interactions between exercise/energy restriction and alterations in macronutrient content remain top priorities for the field to identify optimal behavioral treatments to reduce postprandial lipemia.

Is measurement of non-HDL cholesterol an effective way to identify the metabolic syndrome?

BACKGROUND AND AIMS

The metabolic syndrome (MetS) has been shown to predict coronary heart disease (CHD). Non-high-density lipoprotein cholesterol (non-HDL-C) is also known to predict CHD, and recent evidence indicated non-HDL-C was able to predict MetS in adolescents. The study aim was to determine whether non-HDL-C serves as a useful metabolic marker for MetS in adults.

METHODS AND RESULTS

Fasting non-HDL-C measurements were obtained in 366 non-diabetic adults not on lipid-lowering therapy. In addition to traditional non-HDL-C cut-points based on Adult Treatment Panel III guidelines, receiver-operating characteristic curve analysis was used to identify an optimal cut-point for predicting MetS. A secondary goal was to assess the relationship between non-HDL-C and insulin resistance, defined as the upper tertile of steady-state plasma glucose concentrations measured during the insulin suppression test. Prevalence of MetS was 40% among participants. Those with MetS had higher mean non-HDL-C (4.17 ± 1.0 vs 3.70 ± 0.85 mmol/L, p < 0.001), and the upper vs lower tertile of non-HDL-C concentrations was associated with 1.8-fold increased odds of MetS (p < 0.05). Traditional non-HDL-C cut-points ≥ 4.14 and ≥ 4.92 mmol/L demonstrated respective sensitivities 46% and 24% (specificities 72% and 89%) for identifying MetS. The optimal non-HDL-C cut-point ≥ 4.45 mmol/L had sensitivity 39% (specificity 82%). Comparable results were observed when non-HDL-C was used to identify insulin resistance.

CONCLUSION

While MetS was associated with increased non-HDL-C, an effective non-HDL-C threshold to predict MetS in adults was not identified. Dyslipidemic nuances may explain why non-HDL-C may be less useful as a metabolic marker for MetS and/or insulin resistance than for CHD.

Insulin resistance and coronary heart disease in nondiabetic individuals

The goal of this review was to summarize evidence supporting the view that insulin resistance/compensatory hyperinsulinemia play an important role in the pathogenesis of coronary heart disease (CHD) in nondiabetic individuals. Results of case-control and epidemiological studies in nondiabetic individuals will be reviewed to examine the link between insulin resistance/compensatory hyperinsulinemia, associated abnormalities, and CHD. The primary focus of the review will be on the central role that dyslipidemia plays in the link between insulin resistance/compensatory hyperinsulinemia and CHD. Additional issues to be addressed include the following: (1) the relationship among obesity, insulin resistance, and CHD; (2) a listing of other abnormalities that contribute to risk of CHD in insulin-resistant individuals; and (3) discussion of the importance of differential tissue insulin sensitivity in the development of abnormalities that increase CHD risk in insulin-resistant, nondiabetic individuals. The information will reflect the author's decision as to what issues are believed to be of particular relevance or less well appreciated concerning the complex relationship between insulin resistance and CHD. Resistance to insulin-mediated glucose disposal and hyperinsulinemia is a common finding in apparently healthy individuals and is associated with a number of abnormalities that greatly increase risk of CHD.

Insulin resistance and the relationship of a dyslipidemia to coronary heart disease: the Framingham Heart Study

OBJECTIVE

The goal of this study was to examine the effect of insulin resistance (IR) in subjects without diabetes on the relationship of a dyslipidemia with high triglycerides and low high-density lipoprotein cholesterol (HDL-C) to the development of coronary heart disease (CHD).

METHODS AND RESULTS

Lower and higher fasting plasma HDL-C and triglyceride concentrations (defined at the study population median) and presence or absence of IR (defined by upper quartile Homeostatic Model Assessment values) were related to the development of myocardial infarction or CHD death in Framingham Heart Study participants without diabetes or a history of CHD (n=2910) attending the 1991 to 1995 examination. During follow-up (mean, 14 years), 128 participants experienced an incident CHD event. With Kaplan-Meier plots, the incidence of CHD was significantly greater with than without IR at either the lowest HDL-C or the highest triglycerides (P<0.001). In multivariable Cox models adjusted for major CHD risk factors, including waist circumference, only subgroups with IR had a significantly higher incidence of CHD. Compared with a reference group without IR and with higher-than-median HDL-C or lower-than-median triglycerides, the hazard ratio (HR) for incident events was significant with only IR and a lower HDL-C (HR 2.83, P<0.001) or higher triglycerides (HR 2.50, P<0.001). These findings were similar in men and women.

CONCLUSIONS

In this community-based sample exclusive of diabetes, incident CHD risk associated with plasma HDL-C or triglycerides was significantly increased only in the presence of IR.

Fructose impairs glucose-induced hepatic triglyceride synthesis

Obesity, type 2 diabetes and hyperlipidemia frequently coexist and are associated with significantly increased morbidity and mortality. Consumption of refined carbohydrate and particularly fructose has increased significantly in recent years and has paralled the increased incidence of obesity and diabetes. Human and animal studies have demonstrated that high dietary fructose intake positively correlates with increased dyslipidemia, insulin resistance, and hypertension. Metabolism of fructose occurs primarily in the liver and high fructose flux leads to enhanced hepatic triglyceride accumulation (hepatic steatosis). This results in impaired glucose and lipid metabolism and increased proinflammatory cytokine expression. Here we demonstrate that fructose alters glucose-stimulated expression of activated acetyl CoA carboxylase (ACC), pSer hormone sensitive lipase (pSerHSL) and adipose triglyceride lipase (ATGL) in hepatic HepG2 or primary hepatic cell cultures in vitro. This was associated with increased de novo triglyceride synthesis in vitro and hepatic steatosis in vivo in fructose- versus glucose-fed and standard-diet fed mice. These studies provide novel insight into the mechanisms involved in fructose-mediated hepatic hypertriglyceridemia and identify fructose-uptake as a new potential therapeutic target for lipid-associated diseases.

Health implications of fructose consumption: A review of recent data

This paper reviews evidence in the context of current research linking dietary fructose to health risk markers.Fructose intake has recently received considerable media attention, most of which has been negative. The assertion has been that dietary fructose is less satiating and more lipogenic than other sugars. However, no fully relevant data have been presented to account for a direct link between dietary fructose intake and health risk markers such as obesity, triglyceride accumulation and insulin resistance in humans. First: a re-evaluation of published epidemiological studies concerning the consumption of dietary fructose or mainly high fructose corn syrup shows that most of such studies have been cross-sectional or based on passive inaccurate surveillance, especially in children and adolescents, and thus have not established direct causal links. Second: research evidence of the short or acute term satiating power or increasing food intake after fructose consumption as compared to that resulting from normal patterns of sugar consumption, such as sucrose, remains inconclusive. Third: the results of longer-term intervention studies depend mainly on the type of sugar used for comparison. Typically aspartame, glucose, or sucrose is used and no negative effects are found when sucrose is used as a control group.Negative conclusions have been drawn from studies in rodents or in humans attempting to elucidate the mechanisms and biological pathways underlying fructose consumption by using unrealistically high fructose amounts.The issue of dietary fructose and health is linked to the quantity consumed, which is the same issue for any macro- or micro nutrients. It has been considered that moderate fructose consumption of ≤50g/day or ~10% of energy has no deleterious effect on lipid and glucose control and of ≤100g/day does not influence body weight. No fully relevant data account for a direct link between moderate dietary fructose intake and health risk markers.

Metabolic effects of obesity: A review

With the many recent advances in the biomedical world, vast changes are taking place in our growing knowledge of the physiological aspects of almost all the tissues and organs of the human body. One of the most prevalent topics of discussion is the question of obesity and its effect on the metabolic changes in the human body. The original classical role of adipose tissue as an energy storage organ has been greatly modified. We now know that it is an endocrine organ, producing adipokines like leptin, adiponectin, visfatin, resistin, apelin, etc, which modulate metabolic processes in the body. Since obesity is associated with an increase in the adipose tissue mass, these hormones may be expected to be produced in increased concentrations and may thus have a significant impact on the macronutrient metabolism. Further, these adipokines may interact with long term energy modulators like insulin. Even though the scientific community has started unravelling the mysteries of the close linkage between obesity, its hormones and their physiological effects, a lot still remains to be discovered. The present discussion makes an attempt to trace the basic modern day concepts of the role of obesity in various metabolic processes.

Effects of dietary chromium (III) picolinate on growth performance, respiratory rate, plasma variables, and carcass traits of pigs fed high-fat diets

We investigated the effects of supplemental chromium (Cr) as Cr (III) picolinate on pigs fed high-fat diets (HFD) in a 56-day experiment. Thirty-two crossbred pigs (9.6 kg) were allotted to four treatments with four blocks and two pigs/pen. Treatments included: (1) low-fat diet (fat < 3.5%; LFD) with no Cr, (2) HFD (fat > 30%) with no Cr, (3) HFD with 1,000 ppb Cr, and (4) HFD with 2,000 ppb Cr. Pigs fed HFD gained weight faster, consumed less, and had lower feed:gain (p < 0.05). Pigs fed HFD had higher respiration rates than pigs fed LFD on d 41 (p < 0.05). Plasma insulin on d 14 linearly decreased with Cr (p = 0.05). Plasma cholesterol concentrations were higher in the pigs fed HFD than those fed LFD, but were largely unaffected by supplemental Cr. Consumption of HFD resulted in greater carcass weight, perirenal fat, and backfat measures (p < 0.01) compared with the LFD group. Cr resulted in linear reductions of hot carcass weight (p = 0.08) and average backfat (p < 0.05). The effects of Cr on carcass fat measures were more pronounced in castrated males than in females. These results indicate that Cr attenuates some effects of a HFD, mainly body fat accretion of pigs, and especially in castrated pigs.

Type I diabetes and physical exercise

Metabolic effects of physical exercise in type I diabetes are reviewed. Physical training leads to an increased insulin sensitivity but does not seem to influence the metabolic control. However, the metabolic control is of importance for the exercise results. Patients in a good control do not differ from normal individuals concerning working capacity, recovery after hypoglycemia and hormonal balance. Furthermore, abnormalities in the blood glucose homeostasis during exercise in type I diabetes are discussed as well as potential beneficial effects of physical training in the prevention of cardiovascular disease.

Nutrient modulation of insulin secretion

The presence of different nutrients regulates the beta-cell response to secrete insulin to maintain glucose in the physiological range and appropriate levels of fuels in different organs and tissues. Glucose is the only nutrient secretagogue capable of promoting alone the release of insulin release. The mechanisms of Insulin secretion are dependent or independent of the closure of ATP-sensitive K(+) channels. In addition, insulin secretion in response to glucose and other nutrients is modulated by several hormones as incretins, glucagon, and leptin. Fatty acids (FAs), amino acids, and keto acids influence secretion as well. The exact mechanism for which nutrients induce insulin secretion is complicated because nutrient signaling shows one of the most complex transduction systems, which exists for the reason that nutrient have to be metabolized. FAs in the absence of glucose induce FA oxidation and insulin secretion in a lesser extent. However, FAs in the presence of glucose produce high concentration of malonyl-CoA that repress FA oxidation and increase the formation of LC-CoA amplifying the insulin release. Long-term exposure to fatty acids and glucose results in glucolipotoxicity and decreases in insulin release. The amino acid pattern produced after the consumption of a dietary protein regulates insulin secretion by generating anaplerotic substrates that stimulates ATP synthesis or by activating specific signal transduction mediated by mTOR, AMPK, and SIRT4 or modulating the expression of genes involved in insulin secretion. Finally, dietary bioactive compounds such as isoflavones play an important role in the regulation of insulin secretion.

Moderate carbohydrate, moderate protein weight loss diet reduces cardiovascular disease risk compared to high carbohydrate, low protein diet in obese adults: A randomized clinical trial

Background

To evaluate the metabolic effects of two weight loss diets differing in macronutrient composition on features of dyslipidemia and post-prandial insulin (INS) response to a meal challenge in overweight/obese individuals.

Methods

This study was a parallel-arm randomized 4 mo weight loss trial. Adults (n = 50, 47 ± 7 y) matched on BMI (33.6 ± 0.6 kg/m², P = 0.79) consumed energy restricted diets (deficit ~500 kcal/d): PRO (1.6 g.kg^-1.d^-1 protein and < 170 g/d carbohydrate) or CHO (0.8 g.kg^-1.d^-1 protein and > 220 g/d carbohydrate) for 4 mos. Meal challenges of respective diets were utilized for determination of blood lipids and post-prandial INS and glucose response at the beginning and end of the study.

Results

There was a trend for PRO to lose more weight (-9.1% vs. -7.3%, P = 0.07) with a significant reduction in percent fat mass compared to CHO (-8.7% vs. -5.7%; P = 0.03). PRO also favored reductions in triacylglycerol (-34% vs. -14%; P < 0.05) and increases in HDL-C (+5% vs. -3%; P = 0.05); however, CHO favored reduction in LDL-C (-7% vs. +2.5%; P < 0.05). INS responses to the meal challenge were improved in PRO compared to CHO (P < 0.05) at both 1 hr (-34.3% vs. -1.0%) and 2 hr (-9.2% vs. +46.2%), an effect that remained significant after controlling for weight or fat loss (both P < 0.05).

Conclusion

A weight loss diet with moderate carbohydrate, moderate protein results in more favorable changes in body composition, dyslipidemia, and post-prandial INS response compared to a high carbohydrate, low protein diet suggesting an additional benefit beyond weight management to include augmented risk reduction for metabolic disease.

Estimated liver weight is directly related to hepatic very low-density lipoprotein-triglyceride secretion rate in men

BACKGROUND

Animal studies suggest that liver weight is directly related to hepatic very low-density lipoprotein-triglyceride (VLDL-TG) secretion, independently of body size. This relationship has never been examined in humans.

MATERIALS AND METHODS

We measured VLDL-TG secretion rate by using stable isotope-labelled tracers in 21 healthy, non-obese men (age: 25 +/- 3 years; body mass index: 24.8 +/- 1.6 kg m(-2)), and evaluated the relationship between VLDL-TG secretion and indices of total and regional adiposity (body mass index, total body fat, trunk fat), metabolic parameters (free fatty acid, glucose, and insulin concentrations, homeostasis model assessment index of insulin resistance, resting energy expenditure), and estimated liver weight.

RESULTS

Correlation analysis showed that estimated liver weight was positively associated with total VLDL-TG secretion rate (r = 0.722, P < 0.001), VLDL-TG secretion rate per liter of plasma (r = 0.562, P = 0.008), VLDL-TG secretion rate per kilogram of body weight (r = 0.555, P = 0.009), and VLDL-TG secretion rate per kilogram of liver weight (r = 0.620, P = 0.003). In multiple regression analysis, estimated liver weight was the only significant predictor of VLDL-TG secretion rate regardless of units of expression, explaining 31-52% of total variance; none of the metabolic parameters and indices of body fatness entered the regression models.

CONCLUSIONS

We conclude that estimated liver weight is directly related to hepatic VLDL-TG secretion rate in healthy non-obese men; this relationship is likely not mediated by interindividual variation in body size.

Effect of a high-fat diet on 24-h pattern of circulating levels of prolactin, luteinizing hormone, testosterone, corticosterone, thyroid-stimulating hormone and glucose, and pineal melatonin content, in rats

Circadian rhythmicity is affected in obese subjects. This article analyzes the effect of a high-fat diet (35% fat) on 24-h changes circulating prolactin, luteinizing hormone (LH), testosterone, corticosterone, thyroid-stimulating hormone (TSH) and glucose, and pineal melatonin content, in rats. When body weight of rats reached the values of morbid obesity, the animals were sacrificed at six different time intervals throughout a 24-h cycle, together with age-matched controls fed a normal diet (4% fat). Plasma hormone levels were measured by specific radioimmunoassays and glucose concentration by an automated glucose oxidase method. In rats under a high-fat diet, a significant disruption of the 24-h pattern of plasma TSH, LH, and testosterone and a slight disruption of prolactin rhythm were found. Additionally, high-fat fed rats showed significantly lower total values of plasma TSH and testosterone and absence of correlation between testosterone and circulating LH levels. Plasma corticosterone levels increased significantly in high-fat fed rats and their 24-h variation became blunted. In obese animals, a significant hyperglycemia developed, individual plasma glucose values correlating with circulating corticosterone in high-fat fed rats only. The amplitude of the nocturnal pineal melatonin peak decreased significantly in high-fat fed rats. The results underlie the significant effects that obesity has on circadian organization of hormone secretion.

Metabolic syndrome management

Overweight, obesity and the metabolic syndrome occur in genetically susceptible individuals with environmental influences, and may be further compounded by other disorders of metabolism or pharmacological therapy that increase insulin resistance or promotes weight gain. Treatment of the metabolic syndrome should focus on treatment on [corrected] each individual component, but first, lifestyle modification, including diet and exercise with weight reduction, should be [corrected] the foundation of any successful treatment regimen for the metabolic syndrome. Pharmacological therapy should be individualized and targeted to normalize blood pressure, HDL cholesterol, triglycerides and glucose values. If successful, comprehensive management of the metabolic syndrome promises to delay or prevent the development of coronary heart disease and Type 2 diabetes mellitus.

A1 adenosine receptor partial agonist lowers plasma FFA and improves insulin resistance induced by high-fat diet in rodents

There is substantial evidence in the literature that elevated plasma free fatty acids (FFA) play a role in the pathogenesis of type 2 diabetes. CVT-3619 is a selective partial A(1) adenosine receptor agonist that inhibits lipolysis and lowers circulating FFA. The present study was undertaken to determine the effect of CVT-3619 on insulin resistance induced by high-fat (HF) diet in rodents. HF diet feeding to rats for 2 wk caused a significant increase in insulin, FFA, and triglyceride (TG) concentrations compared with rats fed chow. CVT-3619 (1 mg/kg) caused a time-dependent decrease in fasting insulin, FFA, and TG concentrations. Acute administration of CVT-3619 significantly lowered the insulin response, whereas glucose response was not different with an oral glucose tolerance test. Treatment with CVT-3619 for 2 wk resulted in significant lowering of FFA, TG, and insulin concentrations in rats on HF diet. To determine the effect of CVT-3619 on insulin sensitivity, hyperinsulinemic euglycemic clamp studies were performed in C57BL/J6 mice fed HF diet for 12 wk. Glucose infusion rate was decreased significantly in HF mice compared with chow-fed mice. CVT-3619 treatment 15 min prior to the clamp study significantly (P < 0.01) increased glucose infusion rate to values similar to that for chow-fed mice. In conclusion, CVT-3619 treatment lowers FFA and TG concentrations and improves insulin sensitivity in rodent models of insulin resistance.