A simple measure of insulin resistance

Anti-steatotic effects of PPAR-alpha and gamma involve gut-liver axis modulation in high-fat diet-fed mice

AIM

To evaluate the effects of PPARα and PPARγ activation (alone or in combination) on the gut-liver axis, emphasizing the integrity of the intestinal barrier and hepatic steatosis in mice fed a high saturated fat diet.

METHODS

Male C57BL/6J were fed a control diet (C) or a high-fat diet (HF) for ten weeks. Then, a four-week treatment started: HF-α (WY14643), HF-γ (low-dose pioglitazone), and HF-αγ (combination).

RESULTS

The HF caused overweight, insulin resistance, impaired gut-liver axis, and marked hepatic steatosis. Treatments reduced body mass, improved glucose homeostasis, and restored the gut microbiota diversity and intestinal barrier gene expression. Treatments also lowered the plasma lipopolysaccharide concentrations and favored beta-oxidation genes, reducing macrophage infiltration and steatosis in the liver.

CONCLUSION

Treatment with PPAR agonists modulated the gut microbiota and rescued the integrity of the intestinal barrier, alleviating hepatic steatosis. These results show that these agonists can contribute to metabolic-associated fatty liver disease treatment.

Exercise enhances hepatic mitochondrial structure and function while preventing endoplasmic reticulum stress and metabolic dysfunction-associated steatotic liver disease in mice fed a high-fat diet

Metabolic dysfunction-associated steatotic liver disease (MASLD) has attracted increasing attention from the scientific community because of its severe but silent progression and the lack of specific treatment. Glucolipotoxicity triggers endoplasmic reticulum (ER) stress with decreased beta-oxidation and enhanced lipogenesis, promoting the onset of MASLD, whereas regular physical exercise can prevent MASLD by preserving ER and mitochondrial function. Thus, the hypothesis of this study was that high-intensity interval training (HIIT) could prevent the development of MASLD in high-fat (HF)-fed C57BL/6J mice by maintaining insulin sensitivity, preventing ER stress, and promoting beta-oxidation. Forty male C57BL/6J mice (3 months old) comprised 4 experimental groups: the control (C) diet group, the C diet + HIIT (C-HIIT) group, the HF diet group, and the HF diet + HIIT (HF-HIIT) group. HIIT sessions lasted 12 minutes and were performed 3 times weekly by trained mice. The diet and exercise protocols lasted for 10 weeks. The HIIT protocol prevented weight gain and maintained insulin sensitivity in the HF-HIIT group. A chronic HF diet increased ER stress-related gene and protein expression, but HIIT helped to maintain ER homeostasis, preserve mitochondrial ultrastructure, and maximize beta-oxidation. The increased sirtuin-1/peroxisome proliferator-activated receptor-gamma coactivator 1-alpha expression implies that HIIT enhanced mitochondrial biogenesis and yielded adequate mitochondrial dynamics. High hepatic fibronectin type III domain containing 5/irisin agreed with the antilipogenic and anti-inflammatory effects observed in the HF-HIIT group, reinforcing the antisteatotic effects of HIIT. Thus, we confirmed that practicing HIIT 3 times per week maintained insulin sensitivity, prevented ER stress, and enhanced hepatic beta-oxidation, impeding MASLD development in this mouse model even when consuming high energy intake from saturated fatty acids.

Insulin Resistance/Sensitivity Measures as Screening Indicators of Metabolic-Associated Fatty Liver Disease and Liver Fibrosis

BACKGROUND

Measures of insulin resistance (IR)/sensitivity (IS) are emerging tools to identify metabolic-associated fatty liver disease (MAFLD). However, the comprehensive assessment of the performance of various indicators is limited. Moreover, the utility of measures of IR/IS in detecting liver fibrosis remains unclear.

AIMS

To evaluate the predictive ability of seventeen IR/IS and two beta cell function indices to identify MAFLD and liver fibrosis.

METHODS

A cross-sectional study was conducted on individuals aged 25-75 years. Transient elastography was used to estimate liver stiffness and controlled attenuation parameter. The following measures were computed: homeostatic model assessment (HOMA/HOMA2) for IR, IS, and beta cell function; QUICKI; Bennett index; glucose/insulin; FIRI; McAuley index; Reynaud index; SPISE index; TyG; TyG-BMI; TyG-WC; TyG-WHtR; TG/HDL; and METS-IR. Subgroup analyses were performed according to age, gender, diabetes status, and body weight.

RESULTS

A total of 644 individuals were included in our analysis. MAFLD and significant liver fibrosis were detected in 320 (49.7%) and 80 (12.4%) of the participants, respectively. All measures of IR/IS identified MAFLD and liver fibrosis. However, TyG-WC, TyG-BMI, and TyG-WHtR were the top three indicators that identified MAFLD. Measures that include insulin level in their mathematical calculation, namely, Raynaud index, HOMA-IR, HOMA 2-IR, FIRI, and QUICKI had the best performance in identifying liver fibrosis in the entire population, as well as among the study subgroups.

CONCLUSIONS

TyG-WC, TyG-BMI, and TyG-WHtR were the best predictors of MAFLD. Insulin-based measures had better performances in the detection of advanced fibrosis. This was independent of age, gender, obesity, or diabetes status.

The effect of BsmI (rs1544410) single nucleotide polymorphism of vitamin D receptor (VDR) on insulin resistance in healthy children and adolescents: a cross-sectional study

The increasing prevalence of metabolic syndrome, type 2 diabetes, and insulin resistance are driven by complex interactions between genetic and environmental factors. One of the single nucleotide polymorphisms (SNPs) in the VDR gene associated with vitamin D levels is the rs1544410 SNP. This study examined the association of the rs1544410 polymorphism with insulin resistance to predict and screen for possible association with type 2 diabetes and target these individuals for appropriate treatment. This cross-sectional study examined 270 children and adolescents aged 9 to 18 years. Anthropometric and biochemical parameters were determined. Insulin resistance/sensitivity was determined using Quicki, HOMA-IR, MacAuley, Revised MacAuley, Bennetts, FIRI and insulin-to-glucose ratio. The BsmI single nucleotide polymorphism (rs1544410) was determined using the PCR-RFLP method after extracting DNA from peripheral blood collected from fasted subjects, and the resulting data were analyzed using SPSS software and statistical tests.According to linear regression analysis, a significant difference was found in Insulin to glucose ratio, FIRI and HOMA-IR indices between Bb / bb and BB genotypes and it was observed that individuals with BB genotype polymorphism of BsmI vitamin D receptor gene, after Adjustment of age, sex, BMI are at greater risk for insulin resistance and type 2 diabetes.This study demonstrated that those with the BB genotype of VDR BsmI polymorphism were at higher risk for insulin resistance and developing type 2 DM.

PPARα/γ synergism activates UCP1-dependent and -independent thermogenesis and improves mitochondrial dynamics in the beige adipocytes of high-fat fed mice

OBJECTIVE

The aim of this study was to investigate the role of peroxisome proliferator-activated receptor (PPAR) activation (single PPARα or PPARγ, and dual PPARα/γ) on UCP1-dependent and -independent thermogenic pathways and mitochondrial metabolism in the subcutaneous white adipose tissue of mice fed a high-fat diet.

METHODS

Male C57BL/6 mice received either a control diet (10% lipids) or a high-fat diet (HF; 50% lipids) for 12 wk. The HF group was divided to receive the treatments for 4 wk: HFγ (pioglitazone, 10 mg/kg), HFα (WY-14643, 3.5 mg/kg), and HFα/γ (tesaglitazar, 4 mg/kg).

RESULTS

The HF group was overweight, insulin resistant, and had subcutaneous white adipocyte dysfunction. Treatment with PPARα and PPARα/γ reduced body mass, mitigated insulin resistance, and induced browning with increased UCP1-dependent and -independent thermogenesis activation and improved mitochondrial metabolism to support the beige adipocyte phenotype.

CONCLUSION

PPARα and dual PPARα/γ activation recruited UCP1+ beige adipocytes and favored UCP1-independent thermogenesis, yielding body mass and insulin sensitivity normalization. Preserved mitochondrial metabolism emerges as a potential target for obesity treatment using PPAR agonists, with possible clinical applications.

Absence of the influence of the APOE gene on the incidence of type 2 diabetes mellitus in a cohort of workers: Effect of diet and shift work

BACKGROUND

APOE gene encoded a multifunctional protein in lipid metabolism, also associated with inflammatory markers. Type 2 diabetes (T2D) is a complex metabolic disease related to increased blood glucose, triglycerides and VLDL and associated with different dyslipidaemias. The aim of this study was to analyze whether the APOE genotype could determining the risk of developing T2D in a large cohort of workers.

MATERIAL AND METHODS

Data from the Aragon Workers Health Study (AWHS) (n=4895) were used to investigate the relationship between glycemic levels and APOE genotype. All patients in the AWHS cohort had their blood drawn after an overnight fast and laboratory tests were performed on the same day as the blood drawn. Dietary and physical assessment was assessed by face-to-face interview. APOE genotype was determined by the Sanger sequencing method.

RESULTS

The relationship between APOE genotype and glycemic profile showed that glucose, Hb1Ac, insulin and HOMA levels did not seem to be associated with the APOE genotype (p=0.563, p=0.605, p=0.333 and p=0.276, respectively). In addition, the T2D prevalence did not show an association with the APOE genotype (p=0.354). Along the same lines, blood glucose levels and T2D prevalence did not show association with the APOE allele. Shift work had some effect on the glycaemic profile, showing that night shift workers have significantly lower levels of glucose, insulin and HOMA (p<0.001). However, the APOE genotype did not show difference in the concentration of glycaemic parameters adjusting by sex, age and BMI, work shift and dietary parameters.

CONCLUSION

Glycemic profile and T2D prevalence did not show any significant association with the APOE genotype. Besides, individuals, who worked in non-rotating night shift showed significantly lower glycemic levels, while workers in the morning-afternoon-night shift showed significantly higher values.

Increased vascular risk factors, atherosclerosis, and psychological distress among Indian adults with refractory epilepsy in comparison to well-controlled epilepsy

OBJECTIVE

Comparison of cardiovascular risk factors, atherosclerosis, and psychological distress among adults with refractory versus well-controlled epilepsy.

METHODS

The cross-sectional study consisted of two groups of 40 people each: Group I - People with well-controlled epilepsy, Group II - People with refractory epilepsy. Age- and gender-matched people of 20-50 years were recruited. People who were diabetic, smokers, hypertensive, alcoholic, pregnant, with infections, and lactating women were excluded from the study. Biochemical parameters, fasting glucose, lipid profile, fasting insulin, leptin, adiponectin, Lp[a], hsCRP, TyG INDEX, HOMA1-%S, HOMA1-IR, HOMA1-%B, QUICKI, FIRI, AIP, AC, CLTI, MLTI, CRI-I, CRI-II, and CIMT were estimated. Stress levels [PSS-10, GAD-7 & PHQ-9] were assessed based on the scoring system from the questionnaires.

RESULTS

The existence of metabolic syndrome, levels of triglycerides, TyG index, MDA, OSI, CIMT, AIP, and stress scores [PSS-10, GAD-7 & PHQ-9] were significantly higher in the refractory-epilepsy group in comparison to the well-controlled group. There were associations between LDL -C and CIMT as well as between GAD-7 and CIMT among all the study subjects. There were no significant differences in the levels of glucose homeostasis parameters, hsCRP, leptin, adiponectin, and Lp[a] between the two groups. Based on the ROC analysis, MDA [AUC = 0.853] and GAD-7 [AUC = 0.900] are useful in the differential diagnosis of the study groups.

CONCLUSION

People with refractory epilepsy had increased levels of vascular risk factors, atherosclerosis, and stress levels compared to people with well-controlled epilepsy. Suitable disease management and therapeutic approaches to address cardiovascular and psychological distress could be planned out among people with refractory epilepsy to improve their quality of life.

Leveraging the future of diagnosis and management of diabetes: From old indexes to new technologies

BACKGROUND

Diabetes is a heterogeneous and multifactorial disease. However, glycemia and glycated hemoglobin have been the focus of diabetes diagnosis and management for the last decades. As diabetes management goes far beyond glucose control, it has become clear that assessment of other biochemical parameters gives a much wider view of the metabolic state of each individual, enabling a precision medicine approach.

METHODS

In this review, we summarize and discuss indexes that have been used in epidemiological studies and in the clinical practice.

RESULTS

Indexes of insulin secretion, sensitivity/resistance and metabolism have been developed and validated over the years to account also with insulin, C-peptide, triglycerides or even anthropometric measures. Nevertheless, each one has their own objective and consequently, advantages and disadvantages for specific cases. Thus, we discuss how new technologies, namely new sensors but also new softwares/applications, can improve the diagnosis and management of diabetes, both for healthcare professionals but also for caretakers and, importantly, to promote the empowerment of people living with diabetes.

CONCLUSIONS

In long-term, the solution for a better diabetes management would be a platform that allows to integrate all sorts of relevant information for the person with diabetes and for the healthcare practitioners, namely glucose, insulin and C-peptide or, in case of need, other parameters/indexes at home, sometimes more than once a day. This solution would allow a better and simpler disease management, more adequate therapeutics thereby improving patients' quality of life and reducing associated costs.

The obesity and nonalcoholic fatty liver disease mouse model revisited: Liver oxidative stress, hepatocyte apoptosis, and proliferation

The study revisited the diet-induced obesity (DIO) mice and the nonalcoholic fatty liver disease (NAFLD) pathogenesis to serve as a translational model. Hepatic beta-oxidation pathways, lipogenesis, oxidative stress, hepatocyte apoptosis, and proliferation were investigated in obese mice. Three-month-old male mice were divided according to their diet for fifteen weeks, the control diet (C group, containing 10% energy from fat) and the high-fat diet (HF group, containing 50% energy from fat). Body weight (BW), liver mass, and steatosis were higher in the HF group than in the C group. Also, gene expression related to beta-oxidation and lipogenesis showed an adverse profile, and insulin and glucose signaling pathways were impaired in the HF group compared to the C group. As a result, steatosis was prevalent in the HF group but not in the C group. Furthermore, the pathways that generate NAFLD were negatively modulated by oxidative stress in the HF animals than in the C ones. The caspase 3 immunolabeled HF hepatocytes with increased gene and protein expressions related to apoptosis while proliferating cell nuclear antigen labeled C hepatocytes. In conclusion, the findings in the DIO mouse model reproduce the NAFLD profile relative to the human NAFLD's apoptosis, insulin signaling, lipogenesis, beta-oxidation, and oxidative stress. Therefore, the model is adequate for a translational perspective's morphological, biochemical, and molecular research on NAFLD.

Prediabetes and insulin resistance in a population of patients with heart failure and reduced or preserved ejection fraction but without diabetes, overweight or hypertension

Background

The relationships between glucose abnormalities, insulin resistance (IR) and heart failure (HF) are unclear, especially regarding to the HF type, i.e., HF with reduced (HFrEF) or preserved (HFpEF) ejection fraction. Overweight, diabetes and hypertension are potential contributors to IR in persons with HF. This study aimed to evaluate the prevalence of prediabetes and IR in a population of Vietnamese patients with HFrEF or HFpEF but no overweight, diabetes or hypertension, in comparison with healthy controls, and the relation between prediabetes or IR and HF severity.

Methods

We conducted a prospective cross-sectional observational study in 190 non-overweight normotensive HF patients (114 with HFrEF and 76 with HFpEF, 92.6% were ischemic HF, mean age was 70.1 years, mean BMI 19.7 kg/m²) without diabetes (neither known diabetes nor newly diagnosed by OGTT) and 95 healthy individuals (controls). Prediabetes was defined using 2006 WHO criteria. Glucose and insulin levels were measured fasting and 2 h after glucose challenge. IR was assessed using HOMA-IR and several other indexes.

Results

Compared to controls, HF patients had a higher prevalence of prediabetes (63.2% vs 22.1%) and IR (according to HOMA-IR, 55.3% vs 26.3%), higher HOMA-IR, insulin/glucose ratio after glucose and FIRI, and lower ISIT0 and ISIT120 (< 0.0001 for all comparisons), with no difference for body weight, waist circumference, blood pressure and lipid parameters. Prediabetes was more prevalent (69.3% vs 53.9%, p = 0.03) and HOMA-IR was higher (p < 0.0001) in patients with HFrEF than with HFpEF. Among both HFrEF and HFpEF patients, those with prediabetes or IR had a more severe HF (higher NYHA functional class and NT-proBNP levels, lower ejection fraction; p = 0.04–< 0.0001) than their normoglycemic or non-insulinresistant counterparts, with no difference for blood pressure and lipid parameters.

Conclusion

In non-diabetic non-overweight normotensive patients with HF, the prevalence of prediabetes is higher with some trend to more severe IR in those with HFrEF than in those with HFpEF. Both prediabetes and IR are associated with a more severe HF. The present data support HF as a culprit for IR. Intervention strategies should be proposed to HF patients with prediabetes aiming to reduce the risk of incident diabetes. Studies should be designed to test whether such strategies may translate into an improvement of further HF-related outcomes.

The Quantose Insulin Resistance Test for Maternal Insulin Resistance: A Pilot Study

OBJECTIVE

Insulin resistance (IR) increases during pregnancy which can lead to hyperinsulinemia, gestational diabetes mellitus (GDM), and neonatal hypoglycemia (NH), especially in obese women. Glucose tolerance testing (GTT) is used clinically to evaluate IR in pregnancy. Quantose IR score index is a novel blood screen of IR validated in nonpregnant individuals. The score is generated using an algorithm that combines insulin and three biomarkers of fatty acid pathways (α-hydroxybutyrate, oleic acid, linoleoyl-glycerophospocholine). Our objective was to determine the validity of Quantose IR test (Metabolan Inc. Morrisville, NC) in assessing IR in pregnant obese women, as compared with the homeostatic model assessment of insulin resistance (HOMA-IR), and its ability to predict GDM and NH.

STUDY DESIGN

Women between 10^0/7 and 13^6/7 weeks of gestation with a pre-pregnancy or early pregnancy body mass index more than 30 kg/m², and no pregestational diabetes, were included. Fasting blood samples were collected at 10^0/7 to 13^6/7 (T1) and 24^0/7 to 28^0/7 (T2) weeks. Quantose IR and HOMA-IR were calculated. All women underwent an early (T1; indicated for women with obesity) and a T2 glucose tolerance tests. GDM was diagnosed using the two-step approach, and NH was defined as a neonatal glucose less than 40 mg/dL in the first 24 hours of life. Linear regression and receiver operating characteristic curves were used for analysis.

RESULTS

The trial enrolled 100 patients. Ten subjects (10%) were diagnosed with GDM in the second trimester and none in the first trimester. At T1, Quantose IR (R²= 0.48), but not 1-hour glucose tolerance test (R²= 0.07), correlated with HOMA-IR. Similar correlations were observed at T2. The 1-hour glucose tolerance test followed by HOMA-IR and Quantose IR (area under the curve [AUC]: 0.82, 0.68, and 0.62, respectively) were predictors of GDM. Quantose IR (AUC: 0.74) and 1-hour glucose tolerance test (AUC: 0.72) at T1 and T2 (AUC: 0.75; AUC: 0.93; respectively) were best predictors of NH. The best cut offs, sensitivities, and specificities for prediction of NH were determined.

CONCLUSION

Similar to nonpregnant individuals, Quantose IR appears to be a valid measure of IR in obese pregnant women. First trimester Quantose IR is a predictor of GDM diagnosed in the second trimester and NH. Given that it requires a single blood draw and no glucose challenge, it may be a useful test to evaluate and monitor IR in pregnancy. Our findings may be used as pilot data to explore the potential use of Quantose IR in pregnancy further.

KEY POINTS

· Traditional testing methods for insulin resistance in pregnancy are often performed late, are time consuming, and unpleasant to patients.. · The first trimester one-step Quantose IR test reflects insulin resistance in pregnancy and predicts GDM and neonatal hypoglycemia.. · This is the first known prospective clinical study validating Quantose IR score index in an obstetrical population at risk for developing GDM..

Progressive brown adipocyte dysfunction: whitening and impaired nonshivering thermogenesis as long-term obesity complications

Chronic obesity damages the cytoarchitecture of brown adipose tissue (BAT), leading to whitening of brown adipocytes and impaired thermogenesis, characterizing BAT dysfunction. Understanding the pathways of whitening progression can bring new targets to counter obesity. This study aimed to evaluate the chronic effect (12, 16, and 20 weeks) of a high-fat diet (50% energy as fat) upon energy expenditure, thermogenic markers, and pathways involved in BAT whitening in C57BL/6J mice. Sixty adult male mice comprised six nutritional groups, where the letters refer to the diet type (control, C or high-fat, HF), and the numbers refer to the period (in weeks) of diet administration: C12, HF12, C16, HF16, C20, and HF20. After sacrifice, biochemical, molecular, and stereological analyses addressed the outcomes. The HF groups had overweight, oral glucose intolerance, and hyperleptinemia, resulting in progressive whitening of BAT and decreased numerical density of nuclei per area of tissue compared to age-matched control groups. In addition, the whitening maximization was related to altered batokines gene expression, decreased nonshivering thermogenesis, and body temperature, resulting in low energy expenditure. The HF20 group showed enlarged adipocytes with stable and dysfunctional lipid droplets, followed by inflammation and ER stress. In conclusion, chronic HF diet intake caused time-dependent maximization of whitening with defective nonshivering thermogenesis. Long-term BAT dysfunction includes down-regulated vascularization markers, upregulated inflammasome activation, and ER stress markers.

Markers of insulin resistance in Polycystic ovary syndrome women: An update

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders, affecting 5%-10% of women of reproductive age. The importance of this syndrome lies in the magnitude of associated comorbidities: infertility, metabolic dysfunction, cardiovascular disease (CVD), plus psychological and oncological complications. Insulin resistance (IR) is a prominent feature of PCOS with a prevalence of 35%-80%. Without adequate management, IR with compensatory hyperinsulinemia contributes directly to reproductive dysfunction in women with PCOS. Furthermore, epidemiological data shows compelling evidence that PCOS is associated with an increased risk of impaired glucose tolerance, gestational diabetes mellitus and type 2 diabetes. In addition, metabolic dysfunction leads to a risk for CVD that increases with aging in women with PCOS. Indeed, the severity of IR in women with PCOS is associated with the amount of abdominal obesity, even in lean women with PCOS. Given these drastic implications, it is important to diagnose and treat insulin resistance as early as possible. Many markers have been proposed. However, quantitative assessment of IR in clinical practice remains a major challenge. The gold standard method for assessing insulin sensitivity is the hyperinsulinemic euglycemic glucose clamp. However, it is not used routinely because of the complexity of its procedure. Consequently, there has been an urgent need for surrogate markers of IR that are more applicable in large population-based epidemiological investigations. Despite this, many of them are either difficult to apply in routine clinical practice or useless for women with PCOS. Considering this difficulty, there is still a need for an accurate marker for easy, early detection and assessment of IR in women with PCOS. This review highlights markers of IR already used in women with PCOS, including new markers recently reported in literature, and it establishes a new classification for these markers.

Obesity-Related Insulin Resistance: The Central Role of Adipose Tissue Dysfunction

Obesity is a key player in the onset and progression of insulin resistance (IR), a state by which insulin-sensitive cells fail to adequately respond to insulin action. IR is a reversible condition, but if untreated leads to type 2 diabetes alongside increasing cardiovascular risk. The link between obesity and IR has been widely investigated; however, some aspects are still not fully characterized.In this chapter, we introduce key aspects of the pathophysiology of IR and its intimate connection with obesity. Specifically, we focus on the role of adipose tissue dysfunction (quantity, quality, and distribution) as a driver of whole-body IR. Furthermore, we discuss the obesity-related lipidomic remodeling occurring in adipose tissue, liver, and skeletal muscle. Key mechanisms linking lipotoxicity to IR in different tissues and metabolic alterations (i.e., fatty liver and diabetes) and the effect of weight loss on IR are also reported while highlighting knowledge gaps.

Metabolic Syndrome: Updates on Pathophysiology and Management in 2021

Metabolic syndrome (MetS) forms a cluster of metabolic dysregulations including insulin resistance, atherogenic dyslipidemia, central obesity, and hypertension. The pathogenesis of MetS encompasses multiple genetic and acquired entities that fall under the umbrella of insulin resistance and chronic low-grade inflammation. If left untreated, MetS is significantly associated with an increased risk of developing diabetes and cardiovascular diseases (CVDs). Given that CVDs constitute by far the leading cause of morbidity and mortality worldwide, it has become essential to investigate the role played by MetS in this context to reduce the heavy burden of the disease. As such, and while MetS relatively constitutes a novel clinical entity, the extent of research about the disease has been exponentially growing in the past few decades. However, many aspects of this clinical entity are still not completely understood, and many questions remain unanswered to date. In this review, we provide a historical background and highlight the epidemiology of MetS. We also discuss the current and latest knowledge about the histopathology and pathophysiology of the disease. Finally, we summarize the most recent updates about the management and the prevention of this clinical syndrome.

Breath biomarkers of insulin resistance in pre-diabetic Hispanic adolescents with obesity

Insulin resistance (IR) affects a quarter of the world's adult population and is a major factor in the pathogenesis of cardio-metabolic disease. In this pilot study, we implemented a non-invasive breathomics approach, combined with random forest machine learning, to investigate metabolic markers from obese pre-diabetic Hispanic adolescents as indicators of abnormal metabolic regulation. Using the ReCIVA breathalyzer device for breath collection, we have identified a signature of 10 breath metabolites (breath-IR model), which correlates with Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) (R = 0.95, p < 0.001). A strong correlation was also observed between the breath-IR model and the blood glycemic profile (fasting insulin R = 0.91, p < 0.001 and fasting glucose R = 0.80, p < 0.001). Among tentatively identified metabolites, limonene, undecane, and 2,7-dimethyl-undecane, significantly cluster individuals based on HOMA-IR (p = 0.003, p = 0.002, and p < 0.001, respectively). Our breath-IR model differentiates between adolescents with and without IR with an AUC-ROC curve of 0.87, after cross-validation. Identification of a breath signature indicative of IR shows utility of exhaled breath metabolomics for assessing systemic metabolic dysregulation. A simple and non-invasive breath-based test has potential as a diagnostic tool for monitoring IR progression, allowing for earlier detection of IR and implementation of early interventions to prevent onset of type 2 diabetes mellitus.

Correlation of Surrogate Markers of Insulin Resistance with Fasting Insulin in Type 2 Diabetes Mellitus Patients: A Study of Malwa Population in Punjab, India

Context Insulin resistance (IR) and abnormal insulin secretion play a key role for the development of type 2 diabetes mellitus (DM). Aims We investigated the surrogate markers of IR, i.e., Homeostasis Model Assessment (HOMA), Quantitative Insulin Sensitivity Check Index (QUICKI), McAuley, and Fasting Insulin Resistance Index (FIRI) in type 2 DM patients. Also, fasting insulin (FI) levels were estimated in type 2 diabetics. Further, the correlation of FI with other surrogate markers of IR in type 2 DM was done. Settings and Design A hundred newly diagnosed patients with type 2 DM from Malwa population, Punjab, were considered for evaluation. Another 100 healthy individuals (age and sex-matched) were examined as controls. Methods and Material Fasting blood glucose, FI, and lipid profile were estimated, and IR was calculated using McAuley index (McA), HOMA, QUICKI, and FIRI. Statistical Analysis Used The statistical analysis was performed on the above-mentioned clinical interpretations. The Cohen's kappa test was used to affirm the agreement. Results FI levels in patients with type 2 diabetes were significantly higher (20.8 ± 9.05 µIU/L) than controls (7.93 ± 1.01 µIU/L). IR by surrogate markers was found significant in the study group. The 76% patients with type 2 diabetes ended up as resistant to insulin by FI measurement, almost equivalent to McA, 80%; HOMA, 88%; FIRI, 88%; and QUICKI, 90%. A notable correlation was highlighted between FI and McA manifesting IR ( p < 0.01, r = -0.85). We calculated the statistical correlation of FI with HOMA, QUICKI, and FIRI indices ( p < 0.01, r = 0.93; p < 0.01 r = -0.92; and p < 0.01, r = +0.93, respectively). The agreement visible from Cohen's kappa test also affirms the same ( k = 0.9 for McA). Conclusion We concluded that all the surrogate markers for IR were specific when compared with FI, but in terms of sensitivity McA was found to be more sensitive as it includes markers of dyslipidemia, which is the precipitating factor of metabolic derangements so as the IR in type 2 DM.

Positive association between the ratio of triglycerides to high-density lipoprotein cholesterol and diabetes incidence in Korean adults

BACKGROUND

Insulin resistance is associated with the incidence of diabetes and cardiovascular diseases such as myocardial infarction. The ratio of triglycerides (TG) to high-density lipoprotein cholesterol (HDL-C) (TG/HDL-C ratio) is positively correlated with insulin resistance. This study aimed to investigate the relationship between the TG/HDL-C ratio and the incidence of diabetes in Korean adults.

METHODS

This retrospective study used data from the National Health Insurance Service-National Health Screening Cohort. The TG/HDL-C ratio was divided into three tertiles, the T₁, T₂, and T₃ groups, based on sex. We estimated the hazard ratios (HRs) and 95% confidence intervals (CIs) for diabetes using multivariate Cox proportional hazards regression analyses.

RESULTS

A total of 80,693 subjects aged between 40 and 79 years were enrolled. The median follow-up period was 5.9 years. The estimated cumulative incidence of diabetes in the T₁, T₂, and T₃ groups was 5.94%, 8.23%, and 13.50%, respectively, in men and 4.12%, 4.72%, and 6.85%, respectively, in women. Compared to T₁, the fully adjusted HRs (95% CIs) of the T₂ and T₃ groups for new-onset diabetes were 1.17 (1.06-1.30) and 1.47 (1.34-1.62), respectively, in men and 1.20 (1.02-1.42) and 1.52 (1.30-1.78), respectively, in women.

CONCLUSIONS

Increased TG/HDL-C ratio was significantly associated with a higher risk of new-onset diabetes in both sexes.

Diabetes, insulin resistance, and asthma: a review of potential links

PURPOSE OF REVIEW

Disorders of glucose metabolism, including insulin resistance, prediabetes, and diabetes, have been identified as risk factors for worsened asthma. This review summarizes emerging evidence for their role as modifiable risk factors in asthma, including the potential benefit of diabetes medications on asthma outcomes.

RECENT FINDINGS

Experimental studies show that hyperinsulinemia associated with insulin resistance is associated with airway smooth muscle proliferation and promotes contractility. Epidemiologic studies have identified a higher prevalence of glycemic dysfunction among those with severe and uncontrolled asthma, and longitudinal studies have associated prediabetes and diabetes with higher risk of asthma exacerbations. The potential benefits of thiazolidinediones (TZDs), glucagon-like peptide-1 agonists, and metformin being investigated in asthma, but thus far interventional studies of TZDs have reported null results. On the contrary, observational studies have inconsistently controlled for relevant confounders which leaves conclusions vulnerable to misattribution of relationships due to corelated metabolic disorders, including dyslipidemia.

SUMMARY

Developing evidence suggests that disorders of glucose metabolism may be associated with worsening asthma. However, these conditions arise within a network of obesity-related metabolic diseases that may themselves worsen asthma. Few interventional trials have not identified a benefit, but data have been limited. Additional research is needed to define the potential independent impact of disorders of glucose metabolism in asthma.

Association of apnea-hypopnea index during rapid eye movement sleep with insulin resistance in patients with suspected obstructive sleep apnea: a cross-sectional study

Background

Obstructive sleep apnea (OSA) is associated with insulin resistance. However, the association between special stages of OSA [rapid eye movement (REM) sleep] and insulin resistance is not clear. This study was designed to assess the association of the frequency of respiratory events during REM sleep with insulin resistance in adults with suspected OSA.

Methods

In this cross-sectional study, 4,062 adult participants with suspected OSA who underwent polysomnography in our sleep center between 2009 and 2016 were screened. Polysomnographic variables, biochemical indicators, and physical measurements were collected. Logistic regression analyses were conducted to determine the odds ratios (ORs) and 95% confidence intervals (95% CIs) for insulin resistance as assessed by the presence of hyperinsulinemia, the homeostasis model assessment of insulin resistance (HOMA-IR) index, the fasting insulin resistance index (FIRI), and Bennett’s insulin sensitivity index (ISI).

Results

The final analyses included 2,899 adults with suspected OSA. Multivariate adjustments, including the apnea-hypopnea index (AHI) during non-REM sleep (AHI_NREM), were performed. The AHI during REM sleep (AHI_REM) was found to be independently associated with insulin resistance across increasing AHI_REM quartiles. For hyperinsulinemia the ORs (95% CIs) followed the order of 1.340 (1.022, 1.757), 1.210 (0.882, 1.660), and 1.632 (1.103, 2.416). For abnormal HOMA-IR, ORs (95% CIs) were 1.287 (0.998, 1.661), 1.263 (0.933, 1.711), and 1.556 (1.056, 2.293). For abnormal FIRI, ORs (95% CIs) were 1.386 (1.048, 1.835), 1.317 (0.954, 1.818), and 1.888 (1.269, 2.807). For abnormal Bennett’s ISI, ORs (95% CIs) were 1.297 (1.003, 1.678), 1.287 (0.949, 1.747), and 1.663 (1.127, 2.452). All linear trends were statistically significant (P<0.01). Additionally, the results showed that REM sleep duration was independently associated with hyperinsulinemia (OR =0.777, 95% CI: 0.615–0.982; P<0.05).

Conclusions

AHI_REM was independently associated with hyperinsulinemia and an abnormal HOMA-IR, FIRI, and Bennett’s ISI in adults with suspected OSA. Additionally, REM sleep duration was independently associated with hyperinsulinemia.

Comparison of twenty indices of insulin sensitivity in predicting type 2 diabetes in Japanese Americans: The Japanese American Community Diabetes Study

AIMS

We compared 20 previously reported indices of insulin sensitivity derived from samples during an oral glucose tolerance test (OGTT) to determine which was best in predicting incident type 2 diabetes.

METHODS

We prospectively followed 418 Japanese Americans without diabetes for 10-11 years. We compared ability to predict incident diabetes of 20 insulin sensitivity indices-9 based on fasting samples, 7 based on 2-h and/or fasting samples, and 4 based on multiple samples (0, 30, 60, 120 min) during an OGTT-by integrated discrimination improvement, category free net reclassification improvement, and area under the receiver operator characteristic curve.

RESULTS

There were 95 incident cases of diabetes. The Cederholm and Gutt indices, requiring more than only fasting samples, were the best to predict incident diabetes as judged by integrated discrimination improvement (0.187, 0.184), category free net reclassification improvement (0.962, 1.030), and area under the receiver operator characteristic curve (0.864, 0.863, respectively). Fasting indices were clearly inferior to both the Cederholm and Gutt indices.

CONCLUSIONS

Among the 20 indices, the Cederholm and Gutt indices predicted diabetes best but the Gutt index may be preferable because it requires fewer samples during an OGTT.

Is pasireotide-induced diabetes mellitus predictable? A pilot study on the effect of a single dose of pasireotide on glucose homeostasis

INTRODUCTION

Pasireotide (PAS) is an effective treatment for Cushing's disease (CD) but its use is burdened by an associated high incidence of diabetes mellitus (DM). The aim of this study was to examine the effect of a single subcutaneous injection of PAS on glucose metabolism in CD, and to identify predictors of DM onset.

METHODS

Fifteen patients with CD (13 females, 2 males; median age 43 years [IQR 34-50]) were submitted to an acute PAS test (600 µg s.c.), measuring glucose, insulin, C-peptide, GIP, glucagon, GLP-1, ACTH, and cortisol at the baseline and every 30 min for 2 h. Then they were treated twice daily with PAS 600 µg, and followed up with clinical and hormone assessments for a median of 6 months [2-13].

RESULTS

PAS prompted a significant decrease in all hormonal parameters considered except for glycemia, which increased (as expected), reaching the highest value at 120' (p < 0.0001). Overall, 9/15 patients developed DM within 2 months of starting PAS therapy. There were no differences in age, weight, visceral adiposity, HOMA index, fasting glucose or severity of CD between patients who developed DM and those who did not. Baseline fasting glucagon levels were higher in the DM patients (17.95 [12.45-20.54] vs. 10.53 [8.11-12.33] pmol/L, p = 0.0256), and so were GIP and HbA1c levels (37 [5.5-39.5] vs. 29 [27-31.8] mmol/mol, p = 0.0008). Glucose at 120' was also significantly higher in the DM patients (9.5 [8.65-11.95] vs. 6.85 [4.48-9] mmol/L, p = 0.012).

CONCLUSIONS

PAS was rapidly able to suppress insulin and incretin secretion, with a subsequent rise in glucose levels into the diabetic range. It also induced a significant inhibition of glucagon production. The patients at higher risk of DM during PAS therapy were those with higher glucagon levels, HbA1c > 34.5 mmol/mol, and a glucose peak after PAS administration > 9 mmol/L. CD patients with these features given PAS therapy should therefore be monitored more carefully.

Reducing Glut2 throughout the body does not result in cognitive behaviour differences in aged male mice

Objectives

GLUT2 is a major facilitative glucose transporter, expressed from the SLC2A2 gene, with essential roles in the liver. Recent work in mice has shown that preventing Glut2 production in specific neuronal populations increases sugar-seeking behaviour, highlighting the importance of Slc2a2 gene expression in the brain. It implies that reduced GLUT2 in the brain, due to genetic polymorphisms or disease, impacts health through behaviour change. Defects in glucose transport in the brain are observed in conditions including type-2 diabetes and dementia. Few studies have directly examined the effect of modulating neuronal glucose transporter expression on cognitive function. The aim of this study was to investigate whether inactivating one Slc2a2 allele throughout the body had major effects on cognition. Cognitive tests to assess recognition memory, spatial working memory and anxiety were performed in Slc2a2 whole-body heterozygous mice (i.e. reduced Glut2 mRNA and protein), alongside littermates expressing normal levels of the transporter.

Results

No significant effects on neurological functions and cognitive capabilities were observed in mice lacking one Slc2a2 allele when fed a chow diet. This suggests that the minor variations in GLUT2 levels that occur in the human population are unlikely to influence behaviour and basic cognition.

Anti-steatotic linagliptin pleiotropic effects encompasses suppression of de novo lipogenesis and ER stress in high-fat-fed mice

AIM

To investigate the effects of linagliptin treatment on hepatic energy metabolism and ER stress in high-fat-fed C57BL/6 mice.

METHODS

Forty male C57BL/6 mice, three months of age, received a control diet (C, 10% of lipids as energy, n = 20) or high-fat diet (HF, 50% of lipids as energy, n = 20) for 10 weeks. The groups were randomly subdivided into four groups to receive linagliptin, for five weeks, at a dose of 30 mg/kg/day added to the diets: C, C-L, HF, and HF-L groups.

RESULTS

The HF group showed higher body mass, total and hepatic cholesterol levels and total and hepatic triacylglycerol levels than the C group, all of which were significantly diminished by linagliptin in the HF-L group. The HF group had higher hepatic steatosis than the C group, whereas linagliptin markedly reduced the hepatic steatosis (less 52%, P < 0.001). The expression of Sirt1 and Pgc1a was more significant in the HF-L group than in the HF group. Linagliptin also elicited enhanced GLP-1 concentrations and a reduction in the expression of the lipogenic genes Fas and Srebp1c. Besides, HF-L showed a reduction in the genes related to endoplasmic reticulum stress Chop, Atf4, and Gadd45 coupled with reduced apoptotic nuclei immunostaining.

CONCLUSION

Linagliptin caused a marked reduction in hepatic steatosis as a secondary effect of its glucose-lowering property. NAFLD countering involved reduced lipogenesis, increased beta-oxidation, and relief in endoplasmic reticulum stress, leading to reduced apoptosis and better preservation of the hepatic structure. Therefore, linagliptin may be used, preferably in diabetic patients, to avoid the progression of hepatic steatosis.

Intermittent fasting, adipokines, insulin sensitivity, and hypothalamic neuropeptides in a dietary overload with high-fat or high-fructose diet in mice

The intermittent fasting (IF) might have benefits on metabolism and food intake. Twelve-week old C57BL/6 J mice were fed a control diet (C, 10% kcal fat), a high-fat diet (HF, 50% kcal fat) or a high-fructose diet (HFru, 50% kcal fructose) for 8 weeks, then half of the animals in each group underwent IF (24 h fed, 24 h fasting) for an additional 4 weeks. Although food intake on the fed day remained the same for all groups, all fasting groups showed a reduction in body mass compared to their counterparts. IF reduced total cholesterol, triacylglycerol, fasting glucose, fasting insulin resistance index, and plasma leptin, but increased plasma adiponectin. IF reduced Leptin gene expression in the HF-IF group, but increased proinflammatory markers in the hypothalamus, also in the C-IF group. Both groups HFru-IF and C-IF, showed alterations in the leptin signaling pathway (Leptin, OBRb, and SOCS3), mainly in the HFru-IF group, suggesting leptin resistance. NPY and POMC neuropeptides labeled the neurons of the hypothalamus by immunofluorescence, corroborating qualitatively other quantitative findings of the study. In conclusion, current results are convincing in demonstrating the IF effect on central regulation of food intake control, as shown by NPY and POMC neuropeptide expressions, resulting in a lower weight gain. Besides, IF improves glycemia, lipid metabolism, and consequently insulin and leptin resistance. However, there is increased expression of inflammatory markers in mouse hypothalamus challenged by the HF and HFru diets, which in the long term may induce adverse effects.

Analytical evaluation and clinical application of insulin and C-peptide by a whole blood, lateral flow, point of care (POC) assay system

The analytical performance and clinical application of measuring insulin and connecting peptide (C-peptide) by point of care (POC) assay were evaluated. A POC assay system (SelexOn, Osang Healthcare Inc., Anyang-si, Korea) was evaluated for precision, linearity, limit of blank (LOB), and limit of detection (LOD). Method comparison was performed with the Cobas Elecsys insulin and C-peptide assay (Roche Diagnostics GmbH, Mannheim, Germany) using 215 and 201 patient specimens for insulin and C-peptide, respectively. For clinical application, insulin resistance indices were studied. Homeostasis model assessment (HOMA) 1 and 2, Quantitative insulin sensitivity check index (QUIKI), fasting insulin resistance index (FIRI), and other indices were evaluated. The coefficient of variation (CV) of imprecision for low, medium, and high concentrations was 10.8%1, 15.99%, and 12.05%, respectively, for insulin and 9.21%, 13.51%, and 13.77%, respectively, for C-peptide. The linearity was validated to 839.78 pmol/L for insulin and to 17.30 nmol/L for C-peptide. LOB and LOD were 8.05 and 9.72 pmol/L for insulin and 0.05 and 0.08 nmol/L for C-peptide, respectively. For the method comparison, the regression equation was y = 1.259x - 8.818 (r = 0.957) for insulin and y = 1.163x - 0.088 (r = 0.985) for C-peptide. The ROC value and overall accuracy were as follows: HOMA2 (C-peptide), 0.809, 79.7%; TyG, 0.788, 73.6%; CPR, 0.775, 74.8%; HOMA1, 0.725, 70.3%; QUIKI, 0.720, 70.3%; FIRI, 0.715, 70.1%; McAuley, 0.658, 65.1%; HOMA2 (Insulin), 0.645, 64.7%; Raynaud, 0.611, 61.4%, respectively. The POC assay system for insulin and C-peptide provided reliable results through a rapid and simple test that could be applied to clinical settings.

DNA Methylation of Five Core Circadian Genes Jointly Contributes to Glucose Metabolism: A Gene-Set Analysis in Monozygotic Twins

The timing of daily fluctuations in blood glucose is tightly controlled by the circadian rhythm. DNA methylation accompanies the circadian clock, and aberrant DNA methylation has been associated with circadian disruption and hyperglycemia. However, the precise role of circadian genes methylation in glucose metabolism is unknown. Using a gene-set approach in monozygotic (MZ) twin pairs, we examined the joint effect of 77 CpGs in five core circadian genes (CLOCK, BMAL1, PER1, PER2, PER3) on glucose-related traits in 138 middle-aged, male-male MZ twins (69 pairs). DNA methylation was quantified by bisulfite pyrosequencing. We first conducted matched twin pair analysis to examine the association of single CpG methylation with glucose metabolism. We then performed gene-based and gene-set analyses by the truncated product method to examine the combined effect of DNA methylation at multiple CpGs in a gene or all five circadian genes as a pathway on glucose metabolism. Of the 77 assayed CpGs, only one site was individually associated with insulin resistance at FDR < 0.05. However, the joint effect of DNA methylation in all five circadian genes together showed a significant association with glucose metabolism. Our results may unravel a biological mechanism through which circadian rhythm regulates blood glucose, and highlight the importance of testing the joint effect of multiple CpGs in epigenetic analysis.

The Influence of FTO Polymorphism rs9939609 on Obesity, Some Clinical Features, and Disturbance of Carbohydrate Metabolism in Patients with Psoriasis

Background

Psoriasis is often accompanied by obesity, hyperlipidemia, diabetes, and metabolic syndrome as risk factors of cardiovascular conditions and premature mortality.

Objective

The study was aimed at investigating whether psoriatic patients, who carry risk allele of obesity-related FTO gene, are more predisposed to obesity and metabolic disturbances and whether it influences the severity of psoriasis.

Methods

197 patients with psoriasis, representing Lower Silesia region of Poland, underwent physical examination and anthropometric measurements. Blood samples for biochemical and genetic analysis were collected. All patients were genotyped for FTO gene rs9939609 variant. Identification of SNP was conducted with the use of minisequencing method.

Results

Around 63% of patients were carriers of at least one risk allele A and 20% were AA homozygotes. The A allele was associated with increased BMI and hip and waist circumferences. The carriers of risk allele had increased PASI and CRP values and tended to have an increased insulin concentration.

Conclusion

Psoriatic patients, carriers of risk allele of FTO gene rs9939609, have an increased risk for more severe psoriasis and obesity and may develop obesity-induced insulin resistance.

High fasting C-peptide levels and insulin resistance in non-lean & non-obese (BMI >19 to < 25 kg/m2) Asian Indians with type 2 diabetes are independently associated with high intra-abdominal fat and liver span

BACKGROUND AND OBJECTIVES

We aimed to compare C-peptide levels & measures of insulin resistance in non-lean & non-obese Asian Indian patients with type 2 diabetes (T2DM) vs. non-lean, non-diabetic controls and to correlate with anthropometric measures, volumes of abdominal adipose tissue depots, pancreas, & liver span.

METHODS

Non-lean, non-obese (BMI >19 and < 25 kg/m²) Asian Indian patients with T2DM, (cases n, 87), diagnosed within one year, on metformin mono therapy, were compared to BMI-matched non-diabetic subjects (controls, n, 37). Measures of glycaemia, insulin and C-peptide levels (fasting and post-prandial), lipid profile, and hepatic transaminases were analysed. Abdominal adipose tissue volumes [subcutaneous & intra-abdominal], pancreatic volume and liver span were assessed using 1.5 Tesla MRI scan.

RESULTS

In cases, the mean values of HbA1c, fasting and post prandial insulin and C-peptide levels, and 3 measures of insulin resistance were significantly higher than controls, but not for HOMA-B. Higher fasting C-peptide levels correlated significantly with HOMA-IR (r = 0.42, p < 0.001), Fasting Insulin Resistance Index (r = 0.42, p < 0.001), Bennett's Index (r = 0.38, p < 0.05), and volumes of SCAT and IAAT only in cases. The independent predictors of higher fasting C-peptide level were IAAT volume (β = 0.057; p = 0.002), liver span (β = 0.057, p = 0.005) and fasting insulin levels (β = 0.35, p = 0.02).

CONCLUSION

Higher fasting and post-prandial C-peptide levels and surrogate measures of insulin resistance in non-obese Asian Indian patients with T2DM are independently associated with IAAT volume and liver span.

The Hepatoprotective Effect of Jaboticaba Peel Powder in a Rat Model of Type 2 Diabetes Mellitus Involves the Modulation of Thiol/Disulfide Redox State through the Upregulation of Glutathione Synthesis

Jaboticaba peel powder (JPP) is rich in bioactive compounds, mainly soluble and insoluble polyphenols with great antioxidant properties. The aim of this study is to evaluate the effects of JPP supplementation on the oxidative stress and hepatic damage in a rat model of type 2 diabetes mellitus (T2DM). Diabetic rats received vehicle or JPP at 2.7 (JPP-I), 5.4 (JPP-II), or 10.8 (JPP-III) g/L in drinking water during 8 weeks. JPP-III attenuated hyperglycaemia and dyslipidemia increased by 86% the liver content of nonprotein thiol groups and by 90% the GSH/GSSG ratio by activating glutathione synthesis. Accordingly, JPP supplementation prevented the loss of activity of the sulfhydryl-dependent enzyme δ-aminolaevulinic acid dehydratase and attenuated hepatic injury assessed by the reduction of serum aspartate aminotransferase activity and liver hypertrophy. Our results support that JPP supplementation to T2DM rats decreases hepatic damage most likely by increasing glutathione synthesis and modulating the thiol/disulfide redox balance.

Association between high-fasting insulin levels and metabolic syndrome in non-diabetic middle-aged and elderly populations: a community-based study in Taiwan

OBJECTIVES

We aimed to determine the association between fasting insulin (FI) levels and metabolic syndrome (MetS) in non-diabetic middle-aged and elderly adults in a community in Taiwan.

DESIGN

Cross-sectional observational study.

SETTING

Community-based investigation in Guishan township of northern Taiwan.

PARTICIPANTS

Our study included adults aged 50 years and above during community health examinations between January and October 2014. People with diabetes mellitus were excluded. A total of 321 people were enrolled.

OUTCOME MEASURES

We divided participants according to tertiles of FI as low, medium and high levels. Pearson correlation was assessed between insulin level and each of the diagnostic components of metabolic syndrome (MetS-DCs) with adjustment of age. The prevalence of MetS-DCs based on tertiles of FI were studied and analysed by Cochran-Armitage trend test. The risk for prevalence of MetS in the middle and high insulin group as compared with the low insulin group were assessed by multivariate logistic regression with adjustments for age, gender, smoking, body mass index (BMI), hypertension and hyperlipidaemia. Youden Index was performed for the optimised cut-off value.

RESULTS

Our results showed positive correlation of FI level with systolic blood pressure, waist circumference, fasting plasma glucose and triglyceride levels, while negative correlation was shown with high-density lipoprotein (P<0.001). The prevalence of each MetS-DCs increased as a trend while FI levels increased (P<0.001). OR (95% CI) of MetS was 5.04 (2.15 to 11.81) for high insulin groups compared with the low insulin group after adjusting confounders (P<0.001). Area under receiver operating characteristic curve (ROC) curve (AUC) was 0.78, and cut-off value 7.35 μU/mL for FI was obtained (sensitivity: 0.69; specificity: 0.77).

CONCLUSIONS

Middle-aged and elderly non-diabetic people with increased FI are associated with a higher prevalence of MetS in the community in Taiwan. Furthermore, FI is an independent risk factor of MetS in this study population.

Oxidative stress and kidney injury in trans-radial catheterization

Oxidative stress is linked to coronary artery disease and is a major mechanism in contrast-induced nephropathy. Trans-radial approach in coronary angiography (CA) with minimized peri-procedural bleeding is expected to reduce acute kidney injury incidence. In the present study, oxidative stress patterns observed in radial CA and their associations with early manifestations of kidney injury are described. A total of 20 stable coronary disease patients submitted to CA and 17 sex-matched patients undergoing computed tomography for myoskeletal reasons were enrolled. Reduced glutathione, catalase, thiobarbituric acid reactive species (TBARS) levels and total anti-oxidant status were measured at various time points postangiography. In ischemic patients baseline TBARS levels were 2-fold lower compared to controls, while carbonyls levels were 35% higher. Glutathione was almost 4-fold lower than the control group. Glutathione and lipid peroxidation in ischemic patients gradually increased after contrast medium administration and reached 180% (P<0.001) and 20% (P=0.021) after 4–6 h, respectively. Four patients presented early evidence of contrast-induced nephropathy postangiography, while no control patient developed acute kidney injury. In the multiple logistic regression analysis, only the creatinine levels at baseline influenced the frequency of early contrast-induced nephropathy development (β =0.36, 95% CI: 0.285–0.438, P=0.01). Glutathione low levels were dominant in the baseline values of ischemic patients who developed contrast-induced nephropathy. Glutathione levels rapidly increased while protein oxidation decreased at the expense of lipid peroxidation. In conclusion, early oxidative stress changes occur in trans-radial CA patients with a mild profile, sufficient to mobilize patient antioxidant defenses.

Early detection of metabolic dysregulation using water T2 analysis of biobanked samples

BACKGROUND

The ability to use frozen biobanked samples from cohort studies and clinical trials is critically important for biomarker discovery and validation. Here we investigated whether plasma and serum water transverse relaxation times (T₂) from frozen biobanked samples could be used as biomarkers for metabolic syndrome (MetS) and its underlying conditions, specifically insulin resistance, dyslipidemia, and subclinical inflammation.

METHODS

Plasma and serum aliquots from 44 asymptomatic, non-diabetic human subjects were biobanked at -80°C for 7-9 months. Water T₂ measurements were recorded at 37°C on 50 µL of unmodified plasma or serum using benchtop nuclear magnetic resonance relaxometry. The T₂ values for freshly drawn and once-frozen-thawed ("frozen") samples were compared using Huber M-values (M), Lin concordance correlation coefficients (ρ_c), and Bland-Altman plots. Water T₂ values from frozen plasma and serum samples were compared with >130 metabolic biomarkers and analyzed using multi-variable linear/logistic regression and ROC curves.

RESULTS

Frozen plasma water T₂ values were highly correlated with fresh (M=0.94, 95% CI 0.89, 0.97) but showed a lower level of agreement (ρ_c=0.74, 95% CI 0.62, 0.82) because of an average offset of -5.6% (-7.1% for serum). Despite the offset, frozen plasma water T₂ was strongly correlated with markers of hyperinsulinemia, dyslipidemia, and inflammation and detected these conditions with 89% sensitivity and 91% specificity (100%/63% for serum). Using optimized cut points, frozen plasma and serum water T₂ detected hyperinsulinemia, dyslipidemia, and inflammation in 23 of 44 subjects, including nine with an early stage of metabolic dysregulation that did not meet the clinical thresholds for prediabetes or MetS.

CONCLUSION

Plasma and serum water T₂ values from once-frozen-thawed biobanked samples detect metabolic dysregulation with high sensitivity and specificity. However, the cut points for frozen biobanked samples must be calibrated independent of those for freshly drawn plasma and serum.

Water T2 as an early, global and practical biomarker for metabolic syndrome: an observational cross-sectional study

Background

Metabolic syndrome (MetS) is a highly prevalent condition that identifies individuals at risk for type 2 diabetes mellitus and atherosclerotic cardiovascular disease. Prevention of these diseases relies on early detection and intervention in order to preserve pancreatic β-cells and arterial wall integrity. Yet, the clinical criteria for MetS are insensitive to the early-stage insulin resistance, inflammation, cholesterol and clotting factor abnormalities that characterize the progression toward type 2 diabetes and atherosclerosis. Here we report the discovery and initial characterization of an atypical new biomarker that detects these early conditions with just one measurement.

Methods

Water T₂, measured in a few minutes using benchtop nuclear magnetic resonance relaxometry, is exquisitely sensitive to metabolic shifts in the blood proteome. In an observational cross-sectional study of 72 non-diabetic human subjects, the association of plasma and serum water T₂ values with over 130 blood biomarkers was analyzed using bivariate, multivariate and logistic regression.

Results

Plasma and serum water T₂ exhibited strong bivariate correlations with markers of insulin, lipids, inflammation, coagulation and electrolyte balance. After correcting for confounders, low water T₂ values were independently and additively associated with fasting hyperinsulinemia, dyslipidemia and subclinical inflammation. Plasma water T₂ exhibited 100% sensitivity and 87% specificity for detecting early insulin resistance in normoglycemic subjects, as defined by the McAuley Index. Sixteen normoglycemic subjects with early metabolic abnormalities (22% of the study population) were identified by low water T₂ values. Thirteen of the 16 did not meet the harmonized clinical criteria for metabolic syndrome and would have been missed by conventional screening for diabetes risk. Low water T₂ values were associated with increases in the mean concentrations of 6 of the 16 most abundant acute phase proteins and lipoproteins in plasma.

Conclusions

Water T₂ detects a constellation of early abnormalities associated with metabolic syndrome, providing a global view of an individual’s metabolic health. It circumvents the pitfalls associated with fasting glucose and hemoglobin A1c and the limitations of the current clinical criteria for metabolic syndrome. Water T₂ shows promise as an early, global and practical screening tool for the identification of individuals at risk for diabetes and atherosclerosis.

Electronic supplementary material

The online version of this article (10.1186/s12967-017-1359-5) contains supplementary material, which is available to authorized users.

E4orf1 Enhances Glucose Uptake Independent of Proximal Insulin Signaling

Impaired proximal insulin signaling is often present in diabetes. Hence, approaches to enhance glucose disposal independent of proximal insulin signaling are desirable. Evidence indicates that Adenovirus-derived E4orf1 protein may offer such an approach. This study determined if E4orf1 improves insulin sensitivity and downregulates proximal insulin signaling in vivo and enhances cellular glucose uptake independent of proximal insulin signaling in vitro. High fat fed mice were injected with a retrovirus plasmid expressing E4orf1, or a null vector. E4orf1 significantly improved insulin sensitivity in response to a glucose load. Yet, their proximal insulin signaling in fat depots was impaired, as indicated by reduced tyrosine phosphorylation of insulin receptor (IR), and significantly increased abundance of ectonucleotide pyrophosphatase/phosphodiesterase-1 (ENPP1). In 3T3-L1 pre-adipocytes E4orf1 expression impaired proximal insulin signaling. Whereas, treatment with rosiglitazone reduced ENPP1 abundance. Unaffected by IR-KD (insulin receptor knockdown) with siRNA, E4orf1 significantly up-regulated distal insulin signaling pathway and enhanced cellular glucose uptake. In vivo, E4orf1 impairs proximal insulin signaling in fat depots yet improves glycemic control. This is probably explained by the ability of E4orf1 to promote cellular glucose uptake independent of proximal insulin signaling. E4orf1 may provide a therapeutic template to enhance glucose disposal in the presence of impaired proximal insulin signaling.

Glucose intolerance develops prior to increased adiposity and accelerated cessation of estrous cyclicity in female growth-restricted rats

BACKGROUND

The incidence of metabolic disease increases in early menopause. Low birth weight influences the age at menopause. Thus, this study tested the hypothesis that intrauterine growth restriction programs early reproductive aging and impaired glucose homeostasis in female rats.

METHODS

Estrous cyclicity, body composition, and glucose homeostasis were determined in female control and growth-restricted rats at 6 and 12 mo of age; sex steroids at 12 mo.

RESULTS

Glucose intolerance was present at 6 mo of age prior to cessation of estrous cyclicity and increased adiposity in female growth-restricted rats. However, female growth-restricted rats exhibited persistent estrus and a significant increase in adiposity, fasting glucose, and testosterone at 12 mo of age (P < 0.05). Insulin release in response to a glucose challenge was blunted in conjunction with a reduction in protein expression of pancreatic glucose transporter type 2 and estrogen receptor-α at 12 mo of age in female growth-restricted rats (P < 0.05).

CONCLUSION

This study demonstrated that slow fetal growth programmed glucose intolerance that developed prior to early estrous acyclicity; yet, fasting glucose levels were elevated in conjunction with increased adiposity, accelerated cessation of estrous cyclicity and a shift toward testosterone excess at 12 mo of age in female growth-restricted rats.

Effect of Glycosin alkaloid from Rhizophora apiculata in non-insulin dependent diabetic rats and its mechanism of action: In vivo and in silico studies

BACKGROUND AND AIM

Diabetes mellitus is a complex multifactorial disorder that remains a great challenging task in the clinical practice. Rhizophora apiculata from Indian medicinal mangrove is widely used to treat inflammation, wound healing and diabetes. Bioassay guided fractionation was followed to isolate Glycosin from the ethanolic extract of R. apiculata. The antidiabetic effect of Glycosin in diabetic rats was investigated and determined their possible mechanism of action.

METHODS

Diabetes was induced in adult Wistar rats by a single intraperitoneal injection of streptozotocin and nicotinamide. Based on the oral glucose tolerance test, Glycosin (50mg/kg b.wt.) was orally administrated to diabetic rats for a period of 45 days. In different intervals, blood glucose and body weight were recorded. After 45 days, blood samples were collected to determine serum lipid profile, level of plasma insulin, hemoglobin, liver, and kidney functions using the appropriate tests. In addition the levels of carbohydrate metabolic enzymes in the liver homogenate were also measured. To determine the molecular mechanism of action, we followed the molecular docking of Glycosin in its possible targets, dipeptidyl peptidase-IV (DPP-IV), Peroxisome proliferator-activated receptor gamma (PPARγ), phosphorylated insulin receptor, and protein tyrosine phosphatase 1B (PTP-1B).

RESULTS

Glycosin treatment significantly (p<0.01) reduced the blood-glucose level, increased the body weight, increase hemoglobin, high-density lipoprotein and insulin level, protein, in addition the activity of hexokinase when compared to untreated rats. Decreased activities of liver function enzymes as well as level of urea, and creatinine were observed in Glycosin treated rats. Docking simulation confirmed that Glycosin interacted with DPP-IV, Insulin receptor and PTP-1B and PPARγ with more affinity and binding energy.

CONCLUSION

Glycosin acts as antihyperglycemic agent, associated with antihyperlipidemic and possibility function as a ligand for proteins that are targets for antidiabetes drugs.

Optimal cutoff points for HOMA-IR and QUICKI in the diagnosis of metabolic syndrome and non-alcoholic fatty liver disease: A population based study

AIMS

The present study was carried out to determine the optimal cutoff points for homeostatic model assessment (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI) in the diagnosis of metabolic syndrome (MetS) and non-alcoholic fatty liver disease (NAFLD).

METHODS

The baseline data of 5511 subjects aged ≥18years of a cohort study in northern Iran were utilized to analyze. Receiver operating characteristic (ROC) analysis was conducted to determine the discriminatory capability of HOMA-IR and QUICKI in the diagnosis of MetS and NAFLD. Youden index was utilized to determine the optimal cutoff points of HOMA-IR and QUICKI in the diagnosis of MetS and NAFLD.

RESULTS

The optimal cutoff points for HOMA-IR in the diagnosis of MetS and NAFLD were 2.0 [sensitivity=64.4%, specificity=66.8%] and 1.79 [sensitivity=66.2%, specificity=62.2%] in men and were 2.5 [sensitivity=57.6%, specificity=67.9%] and 1.95 [sensitivity=65.1%, specificity=54.7%] in women respectively. Furthermore, the optimal cutoff points for QUICKI in the diagnosis of MetS and NAFLD were 0.343 [sensitivity=63.7%, specificity=67.8%] and 0.347 [sensitivity=62.9%, specificity=65.0%] in men and were 0.331 [sensitivity=55.7%, specificity=70.7%] and 0.333 [sensitivity=53.2%, specificity=67.7%] in women respectively.

CONCLUSION

Not only the optimal cutoff points of HOMA-IR and QUICKI were different for MetS and NAFLD, but also different cutoff points were obtained for men and women for each of these two conditions.

Peripheral insulin resistance predicts liver damage in nondiabetic subjects with nonalcoholic fatty liver disease

Surrogate indexes of insulin resistance and insulin sensitivity are widely used in nonalcoholic fatty liver disease (NAFLD), although they have never been validated in this population. We aimed to validate the available indexes in NAFLD subjects and to test their ability to predict liver damage also in comparison with the NAFLD fibrosis score. Surrogate indexes were validated by the tracer technique (6,6-D2 -glucose and U-(13) C-glucose) in the basal state and during an oral glucose tolerance test. The best-performing indexes were used in an independent cohort of 145 nondiabetic NAFLD subjects to identify liver damage (fibrosis and nonalcoholic steatohepatitis). In the validation NAFLD cohort, homeostasis model assessment of insulin resistance, insulin to glucose ratio, and insulin sensitivity index Stumvoll had the best association with hepatic insulin resistance, while peripheral insulin sensitivity was most significantly related to oral glucose insulin sensitivity index (OGIS), insulin sensitivity index Stumvoll, and metabolic clearance rate estimation without demographic parameters. In the independent cohort, only oral glucose tolerance test-derived indexes were associated with liver damage and OGIS was the best predictor of significant (≥F2) fibrosis (odds ratio = 0.76, 95% confidence interval 0.61-0.96, P = 0.0233) and of nonalcoholic steatohepatitis (odds ratio = 0.75, 95% confidence interval 0.63-0.90, P = 0.0021). Both OGIS and NAFLD fibrosis score identified advanced (F3/F4) fibrosis, but OGIS predicted it better than NAFLD fibrosis score (odds ratio = 0.57, 95% confidence interval 0.45-0.72, P < 0.001) and was also able to discriminate F2 from F3/F4 (P < 0.003).

CONCLUSION

OGIS is associated with peripheral insulin sensitivity in NAFLD and inversely associated with an increased risk of significant/advanced liver damage in nondiabetic subjects with NAFLD.

Comparison between indexes of insulin resistance for risk prediction of cardiovascular diseases or development of diabetes

AIM

The predictive effect of various insulin resistance indexes for risk of cardiovascular diseases (CVD) or type 2 diabetes (T2DM) is still unclear.

METHODS

One thousand and forty-nine 71-years-old male subjects from the Swedish ULSAM study, mean follow-up 9 years. All subjects performed the euglycemic insulin clamp for M/I [glucose disposal/mean insulin], and 75-g oral glucose tolerance test for Ceder-IR: 1/glucose uptake rate/[mean glucose×log mean insulin]; Matsuda-IR: 1/10,000/square root [glucose0×insulin0×glucose120×insulin120]; Belfiore-IR: 1/([glucose0+glucose120]/normal mean glucose×[insulin0+insulin120]/normal mean insulin)+1); and HOMA-IR: [glucose0×insulin0]/22.5.

RESULTS

Bland-Altman plots showed best agreement between M/I versus Belfiore-IR and Ceder-IR with mean difference near zero, -0.21 to -0.46, while -0.68 to -0.77 for the other indexes. ISI-Ceder was the strongest predictor for incident nonfatal/fatal ischemic heart disease (CHD) or CVD at Cox regression in all subjects, and for incident T2DM at logistic regression in 1024 subjects with no baseline T2DM, with significantly higher hazard ratios or odds ratios than with all other indexes, also with best model fit, after adjusting for clinical characteristics and the traditional cardiovascular risk factors, including metabolic syndrome for CVD risk.

CONCLUSION

Ceder-IR performed strongest as independent predictor for incidences of CHD/CVD and T2DM.

Tumor Necrosis Factor-Α, Interleukin-6, C-Reactive Protein Levels and Insulin Resistance Associated with Type 2 Diabetes in Abdominal Obesity Women

We aim to investigate the association between elevated tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and high sensitivity-C-reactive protein (hs-CRP) with type 2 diabetes mellitus (T2DM) in abdominal obesity (AO) women subjects. A total of 428 AO subjects (age 48.4 ± 10.2 years), and 107 non-AO women subjects (age 48.8 ± 11.8 years) were enrolled for the all biochemistry testing, inflammatory cytokines, fasting insulin and Homeostasis Model Assessment of insulin resistance (HOMA-IR). Body mass index, waist circumference (WC), blood pressure (BP), plasma glucose (Glu), triglyceride (TG), insulin, HOMA-IR and inflammatory cytokines were significantly higher and lower total antioxidant capacity, HDL-C in AO subjects (p < 0.05). WC was significantly correlated with BP, Glu, TG, LDL-C, insulin, HOMA-IR, TNF-α, IL-6 and negative correlation with HDL-C in AO subjects. Elevation of TNF-α, IL-6, hs-CRP and insulin resistance were significantly associated with T2DM in AO subjects, after adjusting with insulin resistance, increased oxidative stress, elevated TG and reduced HDL-C by using multiple logistic regression analysis. In conclusions, elevation of inflammatory cytokines, oxidative stress and insulin resistance were associated with T2DM in AO women subjects. These inflammatory cytokines are positively associated with T2DM and may have a causal relation with an increased oxidative stress and insulin resistance in these AO women subjects.