Current concepts in insulin resistance, type 2 diabetes mellitus, and the metabolic syndrome

TyGIS: improved triglyceride-glucose index for the assessment of insulin sensitivity during pregnancy

Background

The triglyceride-glucose index (TyG) has been proposed as a surrogate marker of insulin resistance, which is a typical trait of pregnancy. However, very few studies analyzed TyG performance as marker of insulin resistance in pregnancy, and they were limited to insulin resistance assessment at fasting rather than in dynamic conditions, i.e., during an oral glucose tolerance test (OGTT), which allows more reliable assessment of the actual insulin sensitivity impairment. Thus, first aim of the study was exploring in pregnancy the relationships between TyG and OGTT-derived insulin sensitivity. In addition, we developed a new version of TyG, for improved performance as marker of insulin resistance in pregnancy.

Methods

At early pregnancy, a cohort of 109 women underwent assessment of maternal biometry and blood tests at fasting, for measurements of several variables (visit 1). Subsequently (26 weeks of gestation) all visit 1 analyses were repeated (visit 2), and a subgroup of women (84 selected) received a 2 h-75 g OGTT (30, 60, 90, and 120 min sampling) with measurement of blood glucose, insulin and C-peptide for reliable assessment of insulin sensitivity (PREDIM index) and insulin secretion/beta-cell function. The dataset was randomly split into 70% training set and 30% test set, and by machine learning approach we identified the optimal model, with TyG included, showing the best relationship with PREDIM. For inclusion in the model, we considered only fasting variables, in agreement with TyG definition.

Results

The relationship of TyG with PREDIM was weak. Conversely, the improved TyG, called TyGIS, (linear function of TyG, body weight, lean body mass percentage and fasting insulin) resulted much strongly related to PREDIM, in both training and test sets (R² > 0.64, p < 0.0001). Bland–Altman analysis and equivalence test confirmed the good performance of TyGIS in terms of association with PREDIM. Different further analyses confirmed TyGIS superiority over TyG.

Conclusions

We developed an improved version of TyG, as new surrogate marker of insulin sensitivity in pregnancy (TyGIS). Similarly to TyG, TyGIS relies only on fasting variables, but its performances are remarkably improved than those of TyG.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01649-8.

Oxidative stress and metabolic diseases: Relevance and therapeutic strategies

Metabolic syndrome (MS) is a prominent cause of death worldwide, posing a threat to the global economy and public health. A mechanism that causes the oxidation of low-density lipoproteins (LDL) is associated with metabolic abnormalities. Various processes are involved in oxidative stress (OS) of lipoprotein. Although the concept of the syndrome has been fiercely debated, this confluence of risk factors is associated with a higher chance of acquiring type 2 diabetes mellitus (T2DM) and atherosclerosis. Insulin resistance has been found to play a significant role in the progression of these metabolism-associated conditions. It causes lipid profile abnormalities, including greater sensitivity to lipid peroxidation, contributing to the increased prevalence of T2DM and atherosclerosis. This review aims to cover the most recent scientific developments in dietary OS, the consequence of metabolic disorders, and their most significant clinical manifestations (T2DM and atherosclerosis). It will also emphasize the effects of dietary approaches in alleviating OS in MS.

Effect of Intermittent Fasting Diet on Glucose and Lipid Metabolism and Insulin Resistance in Patients with Impaired Glucose and Lipid Metabolism: A Systematic Review and Meta-Analysis

The question of whether or not intermittent fasting diets improve the clinical indicators of glycolipid metabolism remains unclear. This study systematically reviewed the relevant clinical trials to evaluate the effects of intermittent fasting diet on glucose and lipid metabolism and insulin sensitivity in patients with metabolic syndrome. To evaluate the effect of intermittent fasting diet intervention on patients with disorders of glucose and lipid metabolism, random-effect or fixed-effect meta-analysis models were used to calculate the average difference before and after intermittent fasting diet intervention and the corresponding 95% confidence intervals (CIs). After intermittent fasting diet intervention, in terms of glucose metabolism, fasting blood glucose reduced by 0.15 mmol/L (95% CI: -0.23; -0.06), glycosylated hemoglobin reduced by 0.08 (95% CIs: -0.25; -0.10), insulin plasma levels reduced by 13.25 uUI (95% CIs: -16.69; -9.82), and HOMA-IR decreased by 0.31 on an average (95% CIs: -0.44; -0.19). In addition, BMI decreased by 0.8 kg/m² (95% CIs: -1.32; -0.28), body weight reduced by 1.87 kg (95% CIs: -2.67; -1.07), and the waist circumference decreased by 2.08 cm (95% CIs: -3.06; -1.10). Analysis of lipid metabolism showed that intermittent fasting diet intervention effectively reduced the total cholesterol level by 0.32 mmol/L (95% CIs: -0.60; -0.05), low-density lipoprotein level by 0.22 mmol/L (95% CIs: -0.37; -0.07), and triglyceride level by 0.04 mmol/L (95% CIs: -0.15; -0.07). Intermittent fasting diets have certain therapeutic effects on blood glucose and lipids in patients with metabolic syndrome and significantly improve insulin resistance. It may be considered as an auxiliary treatment to prevent the occurrence and development of chronic diseases.

Feasibility and acceptability of a home-based resistance training intervention in adolescent and young adult hematopoietic cell transplant survivors

BACKGROUND

Adolescent and young adult (AYA) hematopoietic cell transplantation (HCT) survivors are at increased risk of metabolic syndrome and lean body mass (LBM) deficits. Resistance training (RT) is a potential intervention to improve LBM, metabolic fitness, and reduce risk of cardiovascular disease.

PROCEDURE

Eligible participants ages 13-39 years, 80-120 days post-HCT, transfusion independent, and prednisone dose ≤1 mg/kg/day were approached. Baseline assessments of body composition (DXA), anthropometrics, and strength testing were completed and participants were taught a 12-week, home-based RT intervention with weekly remote coaching. Follow-up assessments were at day +200 (FU1) and +365 post-HCT (FU2). Feasibility targets were (a) 60% enrollment of approached patients, (b) 80% completion of weekly phone calls, and (c) 80% completion of the RT intervention and FU1 assessments. Acceptability was based on positive responses in qualitative interviews.

RESULTS

Twenty of 31 (65%) eligible AYAs enrolled. Three participants failed to complete baseline measurements (2 = scheduling barriers, 1 = passive refusal) and four participants who completed baseline assessments did not receive the intervention (1 = medical reasons, 2 = no longer interested). Of those who completed baseline assessments, 13 received the intervention, completed 88.5% of coaching calls, and 11 (65%) completed FU1. LBM (kg) increased or remained unchanged in nine of nine participants with complete body composition data at FU1 (mean 1.1 kg; 95%CI: 0.4, 1.9). All participants who completed FU1 reported they would recommend the intervention to an AYA HCT survivor.

CONCLUSIONS

A home-based RT intervention in AYA HCT survivors early post HCT is both feasible and acceptable and may maintain or increase LBM.

The relationship between insulin sensitivity and serum antithrombin 3 activity in patients with type 2 diabetes

BACKGROUND

Antithrombin 3 (AT3) is a physiological inhibitor of thrombin, and serum AT3 activity was found to decrease at the status of type 2 diabetes (T2D). T2D was presented with an increased risk of thrombotic complications at the background of impaired insulin sensitivity. The aim of this study was to investigate the relationship between insulin sensitivity indices and serum AT3 activity in patients with T2D.

METHODS

We conducted a cross-sectional study in patients with T2D who consented to participate in the study at the Endocrinology Department of Affiliated 2 Hospital of Nantong University from January 2015 to June 2018. All patients received serum AT3 activity test and 75 g oral glucose tolerance test (OGTT). Basal and systemic insulin sensitivity were assessed by homeostasis model assessment of insulin resistance (HOMA-IR) and Matsuda index (ISIMatsuda), respectively, from the OGTT. And other relevant clinical data were also collected.

RESULTS

Total of 1612 patients with T2D were enrolled in the study, with a mean age of 58.67 ± 13.09 years and a median diabetes duration of 6 years (interquartile range, 1-10 years). Across ascending quartiles of serum AT3 activity, HOMA-IR progressively decreased, while ISIMatsuda progressively increased (all P for trend < 0.001). Moreover, serum AT3 activity was negatively correlated with HOMA-IR (r = -0.189, P < 0.001) and positively correlated with ISIMatsuda (r = 0.221, P < 0.001). After adjusting for other metabolic risk factors, hemostatic parameters and glucose-lowering therapies by multivariate linear regression analysis, HOMA-IR (β = -0.185, t = -5.960, P < 0.001) and ISIMatsuda (β = 0.197, t = 6.632, P < 0.001) remained independently associated with the serum AT3 activity in patients with T2D, respectively.

CONCLUSIONS

Reduced basal and systemic insulin sensitivity are associated with decreased serum AT3 activity in patients with T2D.

Influence of uric acid on the correlation between waist circumference and triglyceride glucose index: an analysis from CHARLS

Background

Waist circumference (WC) and uric acid (UA) are significantly related. Still, their temporal sequence and how the sequence works on future risk of triglyceride glucose (TyG) are unknown, especially in the Chinese population.

Methods

Cross-lagged panel model was used to analyze the reciprocal, longitudinal relationships among a set of interrelated variables. The mediation model was constructed to test the effect of the relationship between WC and UA on TyG.

Results

A total of 5727 subjects were enrolled in our study population, of which 53.5% were women, and the mean age was 59.0 (standard deviation, 8.62) years. After adjusting for traditional confounding factors, the results showed that a higher level of baseline WC was significantly associated with a higher level of follow-up UA (β = 0.003, P = 0.031) and follow-up TyG (β = 0.003, P < 0.001);. Simultaneously, there was no statistical association between the level of baseline UA and the level of follow-up WC (β = − 0.009, P = 0.951). The mediation effects of UA on WC-TyG were estimated to be 18.1% in adults, and 36.2% in women.

Conclusions

The current study demonstrated that higher baseline level of WC probably preceded UA’ level in general population. In addition, UA mediated the relationship of WC to TyG, especially in females. And the possible mechanism would require further clarification.

Glucose Uptake-Stimulating Galloyl Ester Triterpenoids from Castanopsis sieboldii

Using molecular networking-guided isolation, three new galloyl ester triterpenoids (1-3), two new hexahydroxydiphenic acid-conjugated triterpenoids (6 and 7), and four known compounds (4, 5, 8, and 9) were isolated from the fruits and leaves of Castanopsis sieboldii. The chemical structures of 1-3, 6, and 7 were elucidated on the basis of interpreting their NMR, HRESIMS, and ECD spectra. All compounds (1-9) were evaluated for their glucose uptake-stimulating activities in differentiated adipocytes using 2-deoxy-2-[(7-nitro-2,1,3-benzoxadiazol-4-yl)amino]-d-glucose as a fluorescent-tagged glucose probe. Compounds 2 and 9 resulted in a 1.5-fold increase in glucose uptake. Among them, compound 2 from the fruits showed an upregulation of p-AMPK/AMPK ratio in differentiated C2C12 myoblasts to support the mechanism proposed of glucose uptake stimulation.

Exercise Ameliorates Insulin Resistance of Type 2 Diabetes through Motivating Short-Chain Fatty Acid-Mediated Skeletal Muscle Cell Autophagy

Background: Exercise can ameliorate type II diabetes mellitus (T2DM) by regulating intestinal flora metabolites. However, the detailed mechanism needs to be further explored. Methods: A T2DM model using mice was established by feeding them a high-fat diet and giving them subsequent streptozocin injections. Fasting blood glucose and serum insulin were determined by blood glucose meter and radioimmunoassay, respectively. Intestinal flora was measured by 16sRNA sequencing. SCFA content was measured by gas chromatography (GC) or enzyme-linked immunosorbent assay (ELISA). A fluorescently labeled 2-deoxyglucose (2-NBDG) kit was employed to detect glucose uptake capacity, and western blot was utilized to explore the signaling pathway of insulin resistance and cell autophagy. Results: In the T2DM model, along with a reduction in insulin resistance (IR), exercise reversed the decline of intestinal Bacteroidetes and the increase of Firmicutes. For metabolites of Bacteroides, exercise restored the decline in total intestinal and plasma short-chain fatty acids (SCFAs) in T2DM mice. However, the administration of GLPG0974—the inhibitor of G protein-coupled receptor 43 (GPR43), which is the receptor of SCFAs—abolished exercise-mediated alleviation in IR in vivo and acetate-mediated reduction of skeletal muscle IR (SMIR) in vitro. Mechanistically, exercise induced skeletal muscle cell autophagy, thereby ameliorating SMIR, which was neutralized by GLPG0974 exposure. Conclusions: Exercise-mediated SCFAs-upregulation may ameliorate insulin resistance (IR) through increasing autophagy of skeletal muscle cells by binding to GPR43. This study provides a theoretical basis for targeting gut bacterial metabolites to prevent T2DM.

The relationship between components of metabolic syndrome and plasma level of sex hormone-binding globulin

Plasma concentration of sex hormone-binding globulin (SHBG), as an androgen binding protein, is impressed by many physiological and environmental factors. Recent studies have shown that plasma level of SHBG is related to some components of metabolic syndrome (MetS); however, in contrast, few articles failed to show any associations between SHBG and MetS. So, this study was conducted to investigate the relationship between Components of Metabolic Syndrome and Plasma Level of Sex Hormone-Binding Globulin. In this study, after measuring the plasma level of SHBG in 84 individuals, the relation between MetS and the plasma level of SHBG was investigated. After evaluating the plasma level of SHBG and metabolic abnormalities in men and women, we investigated the factors which mentioned above in two groups including patients with and without MetS. Also, the metabolic abnormalities which evaluated in this study including plasma level of 25-hydroxyvitamin D, serum uric acid (SUA), Albumin, lipid profiles and etc. according to five components of MetS. Our result shows that SHBG could contributed to some laboratory parameters such as LDL-C (P<0.05), total cholesterol (P<0.05), triglycerides (P<0.05) and etc. in men, but not in women. On the other hand, we observed that concentration of SHBG is higher in patients with MetS (P<0.05); however, results from our experiment showed that there is no relation between lower level of SHBG and five components of MetS such as central obesity, raised fasting plasma glucose (FPG) (P>0.05), reduced HDL-C (P>0.05), raised triglycerides (P>0.05) and raised blood pressure (P>0.05) in both men and women. There is a significant association between SHBG and Log-Hip Circumference (P<0.05), Non-HDL-C (P<0.05) and Log-25(OH)D (P<0.05) was seen in this cross-section study in both men and women. Results obtained from our study suggest that SHBG is not a powerful enough factor to use as a predictor of MetS alone and there is no association between plasma level of SHBG and development of five components of MetS, however, lower SHBG level may contributed to lipid profiles.

Association between waist circumference and waist-to-height ratio with insulin resistance biomarkers in normal-weight adults working in a private educational institution

AIM

To assess the association between elevated waist circumference (WC) and high waist-to-height ratio (WHtR) with insulin resistance biomarkers.

METHODS

We conducted an analytical cross-sectional study in normal-weight adults. Participants were divided in two groups according to WC or WHtR levels. We considered values of WC ≥ 90 in male participants and WC ≥ 80 in adult women as elevated, and values of WHtR≥0.50 as high, for both genders. Our outcomes were high triglycerides to HDL-cholesterol (TG/HDL-C) ratio and elevated triglycerides and glucose index (TGI). We considered values of TG/HDL-C ratio ≥ 3 as high and TGI values ≥ 8.37 as elevated. We elaborated crude and adjusted Poisson generalized linear models to evaluate the proposed associations and explored the gender interaction using stratified models. We reported the prevalence ratio (PR) with their respective 95% confidence intervals (95%CI).

RESULTS

We analyzed 355 participants. The prevalence of elevated WC and high WHtR was 17.2% (n = 61) and 33.2% (n = 118), respectively, while the prevalence of high TG/HDL-C ratio and elevated TGI was 24.8% (n = 88) and 12.7% (n = 45), respectively. In the adjusted regression model, elevated WC was associated with high TG/HDL-C ratio only in female participants (aPR = 3.61; 95%CI: 1.59-8.20). Similarly, high WHtR was associated with high TG/HDL-C ratio in women (aPR = 2.54; 95%CI:1.08-5.97). We found an association with statistically marginal significance between elevated WC and elevated TGI in women (aPR = 1.54; 95%CI: 0.95-2.50); as well as for the association between high WHtR and elevated TGI in male participants (aPR = 1.87; 95%CI: 1.00-3.50).

CONCLUSION

Elevated WC and high WHtR were associated with a high TG/HDL-C ratio in women. It is necessary to perform prospective follow-up studies in the Peruvian population in order to corroborate our results.

Coagulopathy in Type 2 Diabetes Mellitus: Pathological Mechanisms and the Role of Factor XIII-A Single Nucleotide Polymorphisms

The prevalence of type 2 diabetes mellitus (T2DM) has quadrupled within three decades since 1980, affecting 422 million adults in 2016. It remains one of the most common noncommunicable chronic diseases and the underlying risk factor for cardiovascular diseases worldwide. There are different underlying mechanisms that play a role in the development of pathologies associated with the disease such as hyperglycaemia, oxidative stress, obesity, inflammation and hypercoagulation; each of which are interlinked. Hyperglycaemia, oxidative stress and obesity play a huge role in the activation of inflammation and coagulation. Activation of inflammatory pathways increases the production of thrombin which predisposes the development of thrombotic related diseases. One of the factors that contribute to the increase of thrombin is the impairment of the fibrinolysis process due to decreased expression of tissue-plasminogen activator (tPA) by increased levels of plasminogen activator inhibitor-1 (PAI-1). Coagulation factor XIII (FXIII), a transglutaminase that is composed of subunits A and B (FXIII-A2B2), is essential for the last step of fibrin clot formation in the coagulation pathway. Genetic variation of FXIII-A in the form of single nucleotide polymorphisms (SNPs) alters the activity of FXIII, altering clot properties which influence disease outcomes. This review discusses the link between underlying mechanisms of T2DM, well known FXIII-A variants and coagulation.

Interleukin-4 Boosts Insulin-Induced Energy Deposits by Enhancing Glucose Uptake and Lipogenesis in Hepatocytes

Type 2 diabetes mellitus (T2DM), with dysregulated hepatic gluconeogenesis as the major cause of fasting hyperglycemia, is closely associated with chronic inflammation. We previously demonstrated interleukin-4 (IL-4) improves insulin sensitivity and glucose tolerance while reducing lipid deposits. The present study examined the in vitro effects of IL-4 on insulin signaling molecules, glucose uptake, and lipid metabolism in hepatocytes, as well as in vivo effects on hepatic adiposity, for elucidating the roles of IL-4 in hepatic energy metabolism. Potential interaction between IL-4 and insulin in regulating hepatic metabolism was also investigated. Our results showed that IL-4 enhanced Akt and GSK-3α/β phosphorylations, which in turn promoted glycogen synthesis. IL-4 not only potentiated basal glucose uptake by upregulating glucose transporter 2 expression but also promoted insulin-induced glucose uptake. Additionally, IL-4 increased triglyceride contents through facilitating free fatty acid uptake and expression/activity of lipogenic enzymes. The major effects of IL-4 on the liver were to promote energy storage by boosting insulin-stimulated glucose uptake and lipid synthesis. This study provides evidence to implicate the novel roles of IL-4 in mediating hepatic glucose and lipid metabolism, interactions between immune responses and metabolic homeostasis, and the involvement of IL-4 in metabolic abnormalities.

Insulin resistance in a large cohort of women with polycystic ovary syndrome: a comparison between euglycaemic-hyperinsulinaemic clamp and surrogate indexes

STUDY QUESTION

Could surrogate indexes identify insulin resistant individuals among women with polycystic ovary syndrome (PCOS)?

SUMMARY ANSWER

Surrogate indexes may be able to rule in, but not rule out, insulin resistance in women with PCOS.

WHAT IS KNOWN ALREADY

Insulin resistance is a typical finding of women with PCOS and most clinical information on this issue is based upon surrogate indexes of insulin resistance. However, data on the performance of these indexes in PCOS women are very limited.

STUDY DESIGN SIZE, DURATION

A retrospective analysis of 406 women referred to our outpatient clinic for hyperandrogenism and/or menstrual dysfunction and submitted to hyperinsulinemic euglycaemic clamp between 1998 and 2015.

PARTICIPANTS/MATERIALS, SETTING, METHODS

In total, 375 of these women had PCOS by the Rotterdam criteria and were included in the study. Six surrogate indexes of insulin sensitivity were calculated from glucose and insulin levels, either at fasting (homeostasis model assessment (HOMA), glucose/insulin (G/I) ratio and quantitative insulin sensitivity check index (QUICKI)) or after oral glucose load (Gutt, Stumvoll0-120 and Matsuda).

MAIN RESULTS AND THE ROLE OF CHANCE

Overall, insulin resistance, as identified by the M-clamp value, was found in 74.9% of these women. The percentage was 59.3% in normal-weight vs 77.5% in overweight and 93.9% in obese subjects. All surrogate indexes were highly correlated with the M-clamp values. However, their ability to identify insulin resistant individuals was limited, in terms of sensitivity and especially in normal-weight subjects. ROC analysis showed similar performances of these indexes (AUC values 0.782-0.817).

LIMITATIONS REASONS FOR CAUTION

Potential referral bias of PCOS patients may have caused overestimation of the prevalence of insulin resistance in these women.

WIDER IMPLICATIONS OF THE FINDINGS

By using surrogate indexes many subjects with PCOS may be erroneously diagnosed as insulin sensitive, especially among normal-weight women. These indexes can be used to rule in, but not rule out, insulin resistance in PCOS.

STUDY FUNDING/COMPETING INTEREST(S)

Academic grants to P. Moghetti from the University of Verona. All authors declare no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Adipokines, Inflammation, and Adiposity in Hematopoietic Cell Transplantation Survivors

Adult survivors of acute leukemia in childhood have a higher-than-expected frequency of obesity and are at increased risk for metabolic syndrome and early mortality from cardiovascular disease (CVD). Adipose tissue has been recognized as an endocrine and paracrine organ that secretes various adipokines involved in metabolic regulation and inflammatory processes. In this study, we examined inflammatory factors (IL-6 and TNF-α) and adipokines (adiponectin, leptin), in addition to body composition and adiposity, in cancer survivors who underwent hematopoietic cell transplantation (HCT) during childhood compared with sibling controls. Over 2-year survivors of HCT for hematologic malignancies during childhood were recruited from 2 institutions along with a control population of siblings. Participants underwent evaluation for body composition, anthropometric measurements, and assessment of CVD risk factors and adipokines. Cases were stratified by radiation exposure in the preparative regimen (total body irradiation [TBI] + central nervous system [CNS] irradiation, TBI only, chemotherapy only) and adjusted least squares means were estimated for each adipokine and adjusted by age, sex, race, Tanner stage, and percent fat mass (PFM) percentiles (0-24, 25-74, 75+). A total of 151 HCT survivors and 92 siblings underwent evaluation. Significant differences in mean adipokine levels were detected between survivors and siblings; leptin was significantly higher and adiponectin significantly lower in HCT survivors who received TBI with or without CNS irradiation compared with siblings. IL-6 was significantly higher in all groups of HCT survivors compared with siblings. Body mass index (BMI) was similar in survivors and controls, although PFM was significantly higher in all groups of HCT survivors and lean body mass (LBM) was lower in survivors who received TBI with or without CNS radiation compared with siblings. HCT survivors showed an unfavorable profile of inflammation, adipokines, and adiposity, despite similar BMI as controls. Higher PFM and lower LBM may contribute to these findings. TBI exposure is correlated with greater severity of these observations. Increasing LBM may represent a tangible target for mitigating the high cardiometabolic risks of HCT survivors.

Increased utilization of fructose has a positive effect on the development of breast cancer

Rapid proliferation and Warburg effect make cancer cells consume plenty of glucose, which induces a low glucose micro-environment within the tumor. Up to date, how cancer cells keep proliferating in the condition of glucose insufficiency still remains to be explored. Recent studies have revealed a close correlation between excessive fructose consumption and breast cancer genesis and progression, but there is no convincing evidence showing that fructose could directly promote breast cancer development. Herein, we found that fructose, not amino acids, could functionally replace glucose to support proliferation of breast cancer cells. Fructose endowed breast cancer cells with the colony formation ability and migratory capacity as effective as glucose. Interestingly, although fructose was readily used by breast cancer cells, it failed to restore proliferation of non-tumor cells in the absence of glucose. These results suggest that fructose could be relatively selectively employed by breast cancer cells. Indeed, we observed that a main transporter of fructose, GLUT5, was highly expressed in breast cancer cells and tumor tissues but not in their normal counterparts. Furthermore, we demonstrated that the fructose diet promoted metastasis of 4T1 cells in the mouse models. Taken together, our data show that fructose can be used by breast cancer cells specifically in glucose-deficiency, and suggest that the high-fructose diet could accelerate the progress of breast cancer in vivo.

Myo-inositol and melatonin in the menopausal transition

INTRODUCTION

The aim of the study was to evaluate the effects on serum insulin and serum thyroid profile of a dietary supplement, myo-inositol, given alone or in combination with melatonin to women during menopausal transition.

METHODS

Forty women aged 45-55 years and at least 6 months of amenorrhea were enrolled in this study. They were randomly assigned to two groups of 20 each. One group took myo-inositol (myo-Ins) (2 g twice a day) and the other group took 2 g/d myo-Ins plus 3 g/d melatonin before sleeping. At the beginning of the study and after 6 months, all women were evaluated for the following indices: waist circumference, body mass index, blood pressure, endometrial thickness, as well as serum concentrations of TSH, FT3, FT4 and insulin.

RESULTS

Both at baseline and at 6 months, the two groups were statistically similar for each of the considered indices. If percent changes (Δ%, 6 months over baseline) are contrasted in the two groups, serum TSH decreased in the myo-Ins group but increased in the latter, while serum insulin decreased in both groups.

CONCLUSIONS

The combination of myo-Ins plus melatonin seems to affect positively glucose metabolism, while myo-Ins only seems to improve thyroid function.

Plasma levels of cell adhesion molecules during hyperinsulinemia and modulation of vasoactive mediators

Endothelial expression of cell adhesion molecules (CAMs) plays an important role in atherosclerosis. Atherosclerosis is increased in hyperinsulinemic states, but whether insulin per se is proatherogenic remains unclear. To investigate the effects of hyperinsulinemia on CAM expression, plasma levels of ICAM-1, VCAM-1 and E-selectin were measured before and after forearm infusion of insulin in healthy subjects. Insulin administration for 2 h resulted in signifi-cant hyperinsulinemia, whereas no significant change was observed in soluble CAMs (all p > 0.05). Because insulin stimulates endothelial release of both endothelin-1 (ET-1) and nitric oxide (NO), which may modulate the expression of CAMs, we also investigated the response of CAMs to ET-1 receptor blockade, alone and in combination with NO synthesis inhibition. ET-1 receptor blockade during hyperinsulinemia resulted in a vasodilator response, but did not affect soluble CAMs (all p > 0.05). Superimposition of NO inhibition by l-NMMA reversed the vasodilator effect of ET-1 blockade, without affecting soluble CAMs (all p > 0.05). In conclusion, acute hyperinsulinemia, alone or during ET-1 and NO pathway blockade, does not affect soluble CAMs. These results do not support a direct effect of insulin on endothelial cells to affect leukocyte adhesiveness to the vascular wall.

Review: Vascular protective effects of peroxisome proliferator-activated receptor agonists

ardiovascular disease is significantly increased in patients with the metabolic syndrome and type 2 diabetes. A clustering of risk factors, including dyslipidaemia, insulin resistance, hypertension, inflammation and coagulation disorders are acting in concert to promote cardiovascular events in these patients. Peroxisome proliferator-activated receptors (PPARs) are transcription factors that influence vascular function by altering gene expression in vascular tissue and indirectly via effects on other tissues. Indeed, PPAR activation displays beneficial effects on glucose homeostasis and lipid metabolism, and also on endothelial function and vessel wall inflammation. Clinically used PPARα agonists, such as fibrates, and PPARγ agonists, such as insulin-sensitising thiazolidinediones, may consequently alter the process of atherosclerosis, especially in subjects with the metabolic syndrome and type 2 diabetes. The present review highlights emerging evidence for beneficial effects of PPAR α and PPARγ in the prevention and treatment of atherosclerosis in such high-risk patients.

Effects of Rosiglitazone and Pioglitazone Combined with Metformin on the Prothrombotic State of Patients with Type 2 Diabetes Mellitus and Metabolic Syndrome

In this multicentre, randomized, double-blind, controlled, parallel-group trial, 103 patients with type 2 diabetes mellitus and metabolic syndrome were randomized to receive one of two thiazolidinediones – pioglitazone or rosiglitazone – in combination with 1500 mg/day of metformin, increasing up to 3000 mg/day, for 12 months. Anthropometric, metabolic, coagulation and fibrinolysis parameters were assessed at baseline and after 3, 6, 9 and 12 months. Significant decreases in glycosylated haemoglobin, fasting plasma glucose and post-prandial plasma glucose levels were seen after 9 and 12 months in both groups, and significant decreases in fasting plasma insulin and post-prandial plasma insulin levels were seen after 12 months in both groups. In both groups, improvement in the homeostasis model assessment index compared with baseline was obtained only after 12 months. Plasminogen activator inhibitor-1 levels were significantly lower in both groups after 12 months compared with baseline values. In patients with type 2 diabetes mellitus and metabolic syndrome, the combination of metformin plus thiazolidinediones improved glycaemic control and produced a slight but significant reduction in plasminogen activator inhibitor-1 levels.

Impact of Physical Activity on Glycemic Control and Insulin Resistance: A Study of Community-dwelling Diabetic Patients in Eastern China

Objective The aim of this study was to evaluate the relationship of various intensities of physical activity with glycemic control and insulin resistance in eastern China. Methods A population-based, cross-sectional study was conducted in eastern China. The subjects included 604 community-dwelling people. The participants were classified as insufficiently active (IA); sufficiently active (SA) and very active (VA) according to the International Physical Activity Questionnaire (IPAQ). Insulin sensitivity was assessed using the homeostasis model assessment of insulin resistance (HOMA-IR). Related social, biological, lifestyle factors and clinical characteristics were recorded and used as potential confounders. Results The cohort of 604 type 2 diabetes patients were classified according to the activity level: 107 subjects who were classified as IA, 329 met the criteria for SA, and the rest were VA. The proportion of obese patients, smokers, patients with hypertension, and the body weight, body mass index (BMI), waist circumference, hemoglobin A1c protein (HbA1c), and 2-h postprandial blood glucose (2hPG) were significantly lower in the SA and VA groups than in the IA group (p<0.05 or 0.01). The SA group had lower levels of fasting blood glucose (FPG) and HOMA-IR than the IA and VA groups (p<0.05 or 0.01). HOMA-IR was positively correlated with FPG, 2hPG, HbA1c, waist circumference and BMI. HOMA-IR was negatively correlated with the total walking activity (p<0.05). After adjusting for FPG, 2hPG, HbA1c, waist circumference and BMI among the groups, a partial correlation analysis showed a correlation between HOMA-IR and the total walking activity. Conclusion Physical activity is a significant factor regarding glycemic control and insulin sensitivity, although SA and walking may be superior to VA for ameliorating insulin sensitivity.

Testosterone deficiency, insulin-resistant obesity and cognitive function

Testosterone is an androgenic steroid hormone, which plays an important role in the regulation of male reproduction and behaviors, as well as in the maintenance of insulin sensitivity. Several studies showed that testosterone exerted beneficial effects in brain function, including preventing neuronal cell death, balancing brain oxidative stress and antioxidant activity, improving synaptic plasticity and involving cognitive formation. Although previous studies showed that testosterone deficiency is positively correlated with cognitive impairment and insulin-resistant obesity, several studies demonstrated contradictory findings. Thus, this review comprehensively summarizes the current evidence from in vitro, in vivo and clinical studies of the relationship between testosterone deficiency and insulin-resistant obesity as well as the correlation between either insulin-resistant obesity or testosterone deficiency and cognitive impairment. Controversial reports and the mechanistic insights regarding the roles of testosterone in insulin-resistant obesity and cognitive function are also presented and discussed.

Effect of ketoconazole on lobeglitazone pharmacokinetics in Korean volunteers

PURPOSE

Lobeglitazone, a peroxisome proliferator-activated receptor-γ agonist, is metabolized primarily by the cytochrome P450 (CYP) 3A4 isoenzyme. Individuals concomitantly taking lobeglitazone and a CYP3A4 inhibitor may experience some adverse effects secondary to increased systemic exposure to lobeglitazone. To address such potential concern, we evaluated the effects of ketoconazole, a prototypic CYP3A4 inhibitor, on the pharmacokinetic (PK) properties and associated adverse effects of lobeglitazone.

METHODS

A PK drug-drug interaction study was conducted in healthy individuals between 20 and 45 years old in a randomized, open-label, 2-way crossover design. Even though the PK study was performed on a single dose of lobeglitazone, multiple ketoconazole doses were given to ensure that the full extent of inhibition of CYP3A4 was maintained during the PK sampling. All study participants received a single oral dose of lobeglitazone 0.5 mg with or without 9 oral 200-mg doses of ketoconazole pretreatment twice daily. The primary PK parameter end points (AUC and Cmax) were estimated using noncompartmental analysis, and the 90% CIs for the geometric mean ratios (ratio of lobeglitazone and ketoconazole to lobeglitazone alone) were investigated. Tolerability (adverse events, vital signs, ECG, and laboratory tests) was also assessed.

FINDINGS

A total of 24 Korean men (mean age, 26 years; age range, 20-32 years; mean weight, 68 kg; weight range, 59-81 kg) completed the study and were evaluable for lobeglitazone PK properties and tolerability. The mean (SD) Cmax values of lobeglitazone with and without ketoconazole were 49 (7) ng/mL and 48 (6) ng/mL at 1.5 and 1.0 hours after dosing, respectively. The mean (SD) AUC∞ values were 532 (117) ng·h/mL and 405 (110) ng·h/mL, respectively. Although the Cmax was not significantly affected, the geometric mean ratio for AUC∞ was increased by a point estimate of 1.33 (90% CI, 1.23-1.44). A single oral administration of lobeglitazone 0.5 mg with or without ketoconazole pretreatment did not produce any clinically significant adverse effects on vital signs, 12-lead ECG profiles, or laboratory tests.

IMPLICATIONS

The administration of lobeglitazone, 0.5 mg alone or in combination with multiple doses of ketoconazole, was generally well tolerated. The systemic exposure of lobeglitazone was increased to a modest extent by pretreatment with 9 twice-daily doses of ketoconazole. Clinicaltrials.gov identifier: NCT01330563.

Chemotherapy alone or HSCT after reduced-intensity conditioning for patients with malignant hematologic diseases are not associated to metabolic syndrome: a cross-sectional observational study

The relationship between treatment for hematologic malignancies and risk of developing metabolic syndrome (MS) is controversial; in addition, metabolic changes following hematopoietic stem cell transplantation (HSCT) is an area of growing interest. We documented the presence of MS in patients with hematological malignancies treated with chemotherapy and HSCT. Nutritional status, anthropometrics, and pertinent laboratory parameters were used to evaluate the presence of MS using the Adult Treatment Panel (ATP III) criteria. In the study, 115 patients were included. Using ATP III criteria, MS was identified in 42 (44.7%) patients treated only with chemotherapy and in 8 (33.3%) patients with an HSCT. There was an important but not significant difference in the mean fasting glucose, which was higher in the chemotherapy group (108.32 ± 54.28 vs. 94.48 ± 18.25, P = 0.300). Mean values of biochemical markers and blood pressure were not different between the groups. An increase in central obesity in men with hematological diseases in comparison to the rest of the population was also found (46.7% vs 32.4%). There was no difference in the prevalence of MS between patients with hematologic malignancies receiving an HSCT and those treated with chemotherapy alone.

Hemostatic and Fibrinolytic Changes Are Related to Inflammatory Conditions in Patients with Psoriatic Arthritis — Effect of Different Treatments

Objective.

To prospectively evaluate the effect of tumor necrosis factor (TNF)-α inhibitors on hemostatic and fibrinolytic variables in subjects with psoriatic arthritis (PsA).

Methods.

Among subjects with PsA who were taking traditional disease-modifying antirheumatic drugs (DMARD), 98 patients with active disease who switched to treatment with TNF-α inhibitors were enrolled in this study (Group 1). In parallel, 98 matched subjects with minimal disease activity (MDA) and treated with DMARD were enrolled (Group 2). In all patients, hemostatic and fibrinolytic variables were evaluated at enrollment and after a 6-month followup. Results were stratified according to treatment and to MDA achievement.

Results.

Seventy-six Group 1 and 80 Group 2 subjects completed the 6-month followup. During the followup, significant changes in hemostatic and fibrinolytic variables were found in Group 1, but not in Group 2 subjects. At the end of the followup, patients treated with TNF-α inhibitors showed significantly lower levels of hemostatic and fibrinolytic variables as compared to those treated with traditional DMARD. Among Group 1 subjects, changes in hemostatic and fibrinolytic variable levels were significantly higher in those who achieved MDA versus in those who did not. Multivariate analyses showed that a treatment with TNF-α blockers affected fibrinolytic variables [plasminogen activator inhibitor-1 (PAI-1), tissue plasminogen activator (t-PA)] and some acute-phase proteins (D-dimer, coagulation factor VIII, and von Willebrand factor). In contrast, the MDA achievement during treatment with TNF-α blockers maximally affected fibrinolytic variables (PAI-1 and t-PA).

Conclusion.

TNF-α inhibitors brought about a significant improvement of hemostatic and fibrinolytic balance in subjects with PsA. Maximal changes were found in patients achieving MDA.

Association between sex hormone-binding globulin (SHBG) and metabolic syndrome among men

CONTEXT AND OBJECTIVE

Metabolic syndrome consists of a set of factors that imply increased risk of cardiovascular diseases. The objective here was to evaluate the association between sex hormone-binding globulin (SHBG), sex hormones and metabolic syndrome among men.

DESIGN AND SETTING

Retrospective analysis on data from the study "Endogenous oestradiol but not testosterone is related to coronary artery disease in men", conducted in a hospital in São Paulo.

METHODS

Men (aged 40-70) who underwent coronary angiography were selected. The age, weight, height, waist circumference, body mass index and prevalence of dyslipidemia, hypertension and diabetes of each patient were registered. Metabolic syndrome was defined in accordance with the criteria of the Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults (NCEP-ATPIII). Serum samples were collected to assess the levels of glucose, total cholesterol, HDL-cholesterol (high density lipoprotein), triglycerides, albumin, SHBG, estradiol and total testosterone (TT). The levels of LDL-cholesterol (low density lipoprotein) were calculated using Friedewald's formula and free testosterone (FT) and bioavailable testosterone (BT) using Vermeulen's formula.

RESULTS

141 patients were enrolled in the study. The prevalence of metabolic syndrome was significantly higher in the first SHBG tercile than in the second and third terciles. A statistically significant positive association between the SHBG and TT values was observed, but no such association was seen between SHBG, BT and FT.

CONCLUSION

Low serum levels of SHBG are associated with higher prevalence of metabolic syndrome among male patients, but further studies are required to confirm this association.

Acute effects of different diet compositions on skeletal muscle insulin signalling in obese individuals during caloric restriction

OBJECTIVE

The cellular effects of restricting fat versus carbohydrate during a low-calorie diet are unclear. The aim of this study was to examine acute effects of energy and macronutrient restriction on skeletal muscle insulin signalling in obesity.

MATERIALS/METHODS

Eighteen obese individuals without diabetes underwent euglycemic-hyperinsulinemic clamp and skeletal muscle biopsy after: (a) 5days of eucaloric diet (30% fat, 50% carbohydrate), and (b) 5days of a 30% calorie-restricted diet, either low fat/high carbohydrate (LF/HC: 20% fat, 60% carbohydrate) or high-fat/low carbohydrate (HF/LC: 50% fat, 30% carbohydrate).

RESULTS

Weight, body composition, and insulin sensitivity were similar between groups after eucaloric diet. Weight loss was similar between groups after hypocaloric diet, 1.3±1.3kg (p<0.0001 compared with eucaloric). Whole-body insulin sensitivity was unchanged after calorie restriction and similar between groups. However, ex vivo skeletal muscle insulin signalling differed depending on macronutrient composition of calorie-restricted diet. Skeletal muscle of the LF/HC group had increased insulin-stimulated tyrosine phosphorylation of IRS-1, decreased insulin-stimulated Ser307 phosphorylation of IRS-1, and increased IRS-1-associated phosphatidylinositol (PI)3-kinase activity. Conversely, insulin stimulation of tyrosine phosphorylated IRS-1 was absent and serine 307 phosphorylation of IRS-1 was increased on HF/LC, with blunting of IRS-1-associated PI3-kinase activity.

CONCLUSION

Acute caloric restriction with an LF/HC diet alters skeletal muscle insulin signalling in a way that improves insulin sensitivity, while acute caloric restriction with an HF/LC diet induces changes compatible with insulin resistance. In both cases, ex vivo changes in skeletal muscle insulin signalling appear prior to changes in whole body insulin sensitivity.

Clinical impact of the leptin to soluble leptin receptor ratio on subclinical carotid atherosclerosis in patients with type 2 diabetes

AIM

The adipocyte-derived hormone leptin plays a key role in the regulation of food intake and energy expenditure. Recent studies have suggested that leptin is also involved in the pathogenesis of obesity-associated atherosclerosis and cardiovascular disease. In this study, we investigated the associations of leptin and the soluble leptin receptor (sOb-R) with atherosclerosis in patients with type 2 diabetes.

METHODS

Three hundred seventeen type 2 diabetic subjects were enrolled in this cross-sectional study. Fasting plasma leptin and sOb-R concentrations were measured by enzyme-linked immunosorbent assays. The intima-media thickness (IMT) of the common carotid artery was measured by ultrasound.

RESULTS

The IMT was significantly associated with sOb-R concentrations, age, diabetes duration, serum creatinine (sCre) levels, and systolic blood pressure (SBP), but not with leptin concentrations or the leptin/sOb-R ratio. The concentrations of leptin (r=0.478, p<0.001) and the sOb-R (r= -0.404, p<0.001) and the leptin/sOb-R ratio (r=0.501, p<0.001) were strongly correlated with IMT in subjects treated with insulin for glycemic control, but not in those treated with diet alone or oral hypoglycemic agents. Multiple regression analysis, including age, sex, diabetes duration, body mass index, SBP, HbA1c, triglycerides, LDL-cholesterol, sCre, smoking, and insulin therapy, revealed that plasma leptin and the leptin/sOb-R ratio were independently associated with IMT in subjects treated with insulin.

CONCLUSIONS

Plasma leptin and the leptin/sOb-R ratio are associated with atherosclerosis in patients with type 2 diabetes on insulin therapy, and these associations were independent of obesity and other cardiovascular risk factors.

Low birth weight and elevated head-to-abdominal circumference ratio are associated with elevated fetal glycated serum protein concentrations

OBJECTIVE

To analyze the association between low birth weight, head-to-abdominal circumference ratio, and insulin resistance in early life.

METHOD AND RESULTS

Glycated serum proteins (GSPs) were quantified at delivery in 612 Chinese mother/child pairs serving as a surrogate of maternal and fetal glycemia. Differential ultrasound examination of the fetal's body (head circumference, biparietal diameter, pectoral diameter, abdominal circumference, and femur length) was done in average 1 week prior to delivery. Multivariable regression analysis considering gestational age at delivery, the child's sex, maternal BMI, maternal age at delivery, maternal body weight, and pregnancy-induced hypertension revealed that fetal GSP was inversely associated with birth weight (R² = 0.416; P < 0.001). Fetal GSP was furthermore positively associated with the head-to-abdominal circumference ratio, whereas the maternal GSP was negatively correlated with the offspring's head-to-abdominal circumference ratio (R² = 0.285; P = 0.010 and R² = 0.261; P = 0.020, respectively). The increased head-to-abdominal circumference ratio in newborns with higher fetal GSP is mainly due to a reduced abdominal circumference rather than reduced growth of the brain.

CONCLUSION

The disproportional intrauterine growth is in line with the concept of so-called brain sparing, a mechanism maintaining the intrauterine growth of the brain at the expense of trunk growth. Our data suggest that the low birth weight phenotype, linked to cardiovascular diseases like hypertension in later life, might be a phenotype of disproportional intrauterine growth retardation and early life insulin resistance.

National Cancer Institute-National Heart, Lung and Blood Institute/pediatric Blood and Marrow Transplant Consortium First International Consensus Conference on late effects after pediatric hematopoietic cell transplantation: long-term organ damage and dysfunction

Long-term complications after hematopoietic cell transplantation (HCT) have been studied in detail. Although virtually every organ system can be adversely affected after HCT, the underlying pathophysiology of these late effects remain incompletely understood. This article describes our current understanding of the pathophysiology of late effects involving the gastrointestinal, renal, cardiac, and pulmonary systems, and discusses post-HCT metabolic syndrome studies. Underlying diseases, pretransplantation exposures, transplantation conditioning regimens, graft-versus-host disease, and other treatments contribute to these problems. Because organ systems are interdependent, long-term complications with similar pathophysiologic mechanisms often involve multiple organ systems. Current data suggest that post-HCT organ complications result from cellular damage that leads to a cascade of complex events. The interplay between inflammatory processes and dysregulated cellular repair likely contributes to end-organ fibrosis and dysfunction. Although many long-term problems cannot be prevented, appropriate monitoring can enable detection and organ-preserving medical management at earlier stages. Current management strategies are aimed at minimizing symptoms and optimizing function. There remain significant gaps in our knowledge of the pathophysiology of therapy-related organ toxicities disease after HCT. These gaps can be addressed by closely examining disease biology and identifying those patients at greatest risk for adverse outcomes. In addition, strategies are needed for targeted disease prevention and health promotion efforts for individuals deemed at high risk because of their genetic makeup or specific exposure profile.

Utilization of dietary glucose in the metabolic syndrome

This review is focused on the fate of dietary glucose under conditions of chronically high energy (largely fat) intake, evolving into the metabolic syndrome. We are adapted to carbohydrate-rich diets similar to those of our ancestors. Glucose is the main energy staple, but fats are our main energy reserves. Starvation drastically reduces glucose availability, forcing the body to shift to fatty acids as main energy substrate, sparing glucose and amino acids. We are not prepared for excess dietary energy, our main defenses being decreased food intake and increased energy expenditure, largely enhanced metabolic activity and thermogenesis. High lipid availability is a powerful factor decreasing glucose and amino acid oxidation. Present-day diets are often hyperenergetic, high on lipids, with abundant protein and limited amounts of starchy carbohydrates. Dietary lipids favor their metabolic processing, saving glucose, which additionally spares amino acids. The glucose excess elicits hyperinsulinemia, which may derive, in the end, into insulin resistance. The available systems of energy disposal could not cope with the excess of substrates, since they are geared for saving not for spendthrift, which results in an unbearable overload of the storage mechanisms. Adipose tissue is the last energy sink, it has to store the energy that cannot be used otherwise. However, adipose tissue growth also has limits, and the excess of energy induces inflammation, helped by the ineffective intervention of the immune system. However, even under this acute situation, the excess of glucose remains, favoring its final conversion to fat. The sum of inflammatory signals and deranged substrate handling induce most of the metabolic syndrome traits: insulin resistance, obesity, diabetes, liver steatosis, hyperlipidemia and their compounded combined effects. Thus, a maintained excess of energy in the diet may result in difficulties in the disposal of glucose, eliciting inflammation and the development of the metabolic syndrome.

Low fertility and the risk of type 2 diabetes in women

BACKGROUND

Fertility problems are frequently followed by early menopause, and early menopause has been associated with increased risk of type 2 diabetes (T2D). Thus far, it is unknown whether low fertility is independently associated with future T2D risk.

METHODS

We assessed the association between measures of low fertility and T2D in the Prospect-European Prospective Investigation into Cancer and Nutrition (EPIC) cohort of 17,357 Dutch women, aged 49-70 years at baseline using Cox proportional hazards models, adjusted for various confounders. To investigate whether BMI and waist circumference influence the observed associations, analyses were additionally adjusted for these variables.

RESULTS

At baseline, 332 women had T2D. During a mean follow-up of 9.1 ± 3.6 years, 535 T2D cases occurred. Out of 15,707 Prospect-EPIC women who wanted to get pregnant, 1940 consulted a physician for fertility problems and 700 remained childless. No relation was found between consulting a physician for fertility problems or nulliparity and T2D risk. Of all women who wanted to get pregnant, 3946 (25.1%) had one or more miscarriages, with an average of 1.4 (± 0.9) miscarriages and a maximum of 10 miscarriages. Women who had one or more miscarriage showed the same risk for T2D as women who had no miscarriage. Also, none of the other measures of low fertility were associated with increased risk for T2D.

CONCLUSIONS

Generally, measures of low fertility were not independently associated with a risk of T2D in a cohort of 17 357 Dutch women.

The role of salt in the pathogenesis of fructose-induced hypertension

Metabolic syndrome, as manifested by visceral obesity, hypertension, insulin resistance, and dyslipidemia, is reaching epidemic proportions in the Western World, specifically the United States. Epidemiologic studies suggest that the increased prevalence of metabolic syndrome directly correlates with an increase in the consumption of fructose, mainly in the form of high-fructose corn syrup. This inexpensive alternative to traditional sugar has been increasingly utilized by the food industry as a sweetener since the 1960s. While augmented caloric intake and sedentary lifestyles play important roles in the increasing prevalence of obesity, the pathogenesis of hypertension in metabolic syndrome remains controversial. One intriguing observation points to the role of salt in fructose-induced hypertension. Recent studies in rodents demonstrate that increased dietary fructose intake stimulates salt absorption in the small intestine and kidney tubules, resulting in a state of salt overload, thus setting in motion a cascade of events that will lead to hypertension. These studies point to a novel interaction between the fructose-absorbing transporter, Glut5, and the salt transporters, NHE3 and PAT1, in the intestine and kidney proximal tubule. This paper will focus on synergistic roles of fructose and salt in the pathogenesis of hypertension resulting from salt overload.

Metabolic syndrome and cardiovascular risk in survivors after hematopoietic cell transplantation. Bone Marrow Transplant. 2012;47:619-625. [PMID: 21643022 DOI: 10.1038/bmt.2011.118]

Increasing numbers of hematopoietic cell transplantations (HCTs) are being performed annually with a greater number of long-term survivors. There is increasing concern regarding the late complications and long-term effects that are secondary to treatment exposures before HCT as well as during the HCT conditioning therapy. In both the autologous as well as allogeneic transplant setting, transplant survivors experience mortality rates higher than the general population and the risk of premature cardiovascular (CV)-related death is increased 2.3-fold compared with the general population. The etiology of CV-related deaths in HCT survivors is multifactorial; however, increasing evidence suggests that HCT survivors are at higher risk of developing adverse CV risk factors leading to the development of the metabolic syndrome (a constellation high triglyceride levels, low high-density lipoprotein-cholesterol, hypertension, high fasting blood sugars and increased waist circumference), which then predisposes individuals to risk for early CV-related death. Resistance to insulin is the primary underlying pathophysiologic mechanism that contributes to the development of metabolic syndrome and HCT survivors have been shown to be more likely to develop hypertension, hyperlipidemia and to be insulin resistant. However, the relationship between HCT-related treatment exposures (total body irradiation, high dose chemotherapy, calcineurin inhibitors, steroids, etc) and transplant-related complications (such as GVHD) with the development of CV risk factors and insulin resistance is still in the early stages of investigation. Greater knowledge of the concern regarding CV risk in HCT survivors among both patients and care providers will provide the opportunity for appropriate screening as well as interventions for modifiable risk factors.

Abnormally high prevalence of major components of the metabolic syndrome in subjects with early-onset idiopathic venous thromboembolism

BACKGROUND

Although patients with idiopathic VTE are at higher than normal risk of asymptomatic atherosclerosis and of cardiovascular events, the impact of cardiovascular risk factors on VTE is poorly understood.

OBJECTIVE

To assess the prevalence of the metabolic syndrome and of its components in patients with early-onset idiopathic VTE.

METHODS

As many as 323 patients referred to our Thrombosis Ward for a recent (<6-months) early-onset idiopathic venous thromboembolism (VTE), were compared with 868 gender- and age-matched subjects, in whom a history of venous thrombosis had been excluded, referred during the same period time to our Ward. All had undergone a clinical assessment for smoking habits and for the presence of the components of the metabolic syndrome.

RESULTS

The metabolic syndrome was detected in 76/323 cases (23.5%) and in 81/868 controls (9.3%) (p<0.001; OR:2.990; 95%C.I.:2.119-4.217). Smoking was more common in patients with idiopathic VTE than in controls. In addition to the metabolic syndrome as a whole, its major individual determinants (arterial hypertension, impaired fasting glucose plasma levels, abdominal obesity, hypertriglyceridemia, low HDL-cholesterol) significantly correlated with idiopathic VTE (p always <0.05). The prevalence of thrombotic events was lower in females than in males (p=0.000; OR:2.217), the latter being most often hypertensives, smokers, hypertriglyceridemics, carriers of a metabolic syndrome and of impaired fasting glucose than females. In a multivariate analysis, arterial hypertension, impaired fasting glucose, abdominal obesity, and hypercholesterolemia independently predicted idiopathic venous events.

CONCLUSIONS

Both metabolic syndrome as a whole and its major components individually considered, independently predict early-onset idiopathic VTE.

Carotid intima-media thickness in psoriatic arthritis: differences between tumor necrosis factor-α blockers and traditional disease-modifying antirheumatic drugs

OBJECTIVE

Subjects with psoriatic arthritis (PsA) have an abnormally high prevalence of vascular risk factors (VRFs) and are predisposed to vascular mortality. Tumor necrosis factor (TNF)-α, a major determinant of inflammation, is involved in atherosclerosis. Ultrasonographic carotid intima-media thickness (C-IMT) evaluation allows for subclinical atherosclerosis detection.

METHODS AND RESULTS

Two hundred twenty-four PsA patients (120 on TNF-α blockers and 104 on traditional disease-modifying antirheumatic drugs [DMARDs]) underwent a C-IMT ultrasound assessment. As many as 305 matched subjects without any inflammatory/rheumatologic disease served as controls. The C-IMT of PsA subjects without VRFs was higher (P<0.0001) than that of controls, the C-IMT of PsA subjects with ≥1 VRF(s) was lower (P<0.0001) than that of controls, and the C-IMT was lower (P<0.0001) in those on TNF-α blockers than in those on DMARDs. Carotid plaques were detected in 15.8% of those on TNF-α blockers and in 40.4% of those on DMARDs (P<0.0001). Treatment duration inversely (β=-0.317, P<0.0001) predicted C-IMT in PsA subjects on TNF-α blockers but not in those on DMARDs (P=0.313).

CONCLUSIONS

Among PsA individuals, the C-IMT is higher in subjects on DMARDs than in those on TNF-α blockers. The reduction of inflammation may hamper the cascade that causes the raised vascular risk in PsA patients.

Dietary fructose, salt absorption and hypertension in metabolic syndrome: towards a new paradigm

The worldwide increase in the incidence of metabolic syndrome correlates with marked increase in total fructose intake in the form of high-fructose corn syrup, beverage and table sugar. Increased dietary fructose intake in rodents has been shown to recapitulate many aspects of metabolic syndrome by causing hypertension, insulin resistance and hyperlipidaemia. Recent studies demonstrated that increased dietary fructose intake stimulates salt absorption in the small intestine and kidney tubules, resulting in a state of salt overload and thus causing hypertension. The absorption of salt (sodium and chloride) in the small intestine is predominantly mediated via the chloride/base exchangers DRA (Down Regulated in Adenoma) (SLC26A3) and PAT1 (Putative Anion Transporter 1) (SLC26A6), and the Na(+) /H(+) exchanger NHE3 (Sodium Hydrogen Exchanger3) (SLC9A3). PAT1 and NHE3 also co-localize on the apical membrane of kidney proximal tubule. Luminal fructose stimulated salt absorption in the jejunum and kidney tubules, responses that were significantly diminished in PAT1 null mice. These studies further demonstrated that Glut5 (SLC2A5) is the major fructose-absorbing transporter in the small intestine (and kidney proximal tubule) and plays an essential role in the systemic homeostasis of fructose. Increased dietary fructose intake for several weeks upregulated the expression of NHE3, PAT1 and Glut5 in the intestine and resulted in hypertension in wild-type mice, a response that was almost abolished in PAT1 null mice and abrogated in Glut5 null mice. This article will discuss the interaction of Glut5 with salt-absorbing transporters and review the role of dietary fructose in enhanced salt absorption in intestine and kidney as it relates to the pathogenesis of hypertension in metabolic syndrome.

High prevalence of nonalcoholic fatty liver in patients with idiopathic venous thromboembolism

AIM: To assess the prevalence of nonalcoholic fatty liver disease (NAFLD) in patients with idiopathic venous thromboembolism (VTE).

METHODS: In a case-control study, after excluding subjects with well-consolidated risk factors for VTE, idiopathic VTE was documented in 138 consecutive patients who were referred to our department. Two hundred and seventy-six healthy sex/age/body-mass-index-matched subjects, without any clinical/instrumental evidence of VTE, served as controls. All underwent a clinical/laboratory/ultrasound assessment for the presence of metabolic syndrome and NAFLD.

RESULTS: NAFLD was detected in 112/138 cases (81%) and in 84/276 controls (30%) [risk ratio: 2.7, 95% confidence interval (CI): 2.2-3.2, P < 0.0001]. Metabolic syndrome and smoking habit were more prevalent in patients with idiopathic VTE. The high prevalence of NAFLD in VTE was also confirmed after adjustment for inherited thrombophilia. NAFLD was clearly predicted by VTE (odds ratio: 1.8, 95% CI: 1.2-2.7, P < 0.0001).

CONCLUSION: NAFLD was independently associated with idiopathic VTE.

Adipokine concentrations in nonobese women: a study of reproductive aging, body mass index, and menstrual cycle effects

OBJECTIVE

To explore the influence of reproductive aging, body mass index (BMI), and the menstrual cycle on adiponectin (AD) and leptin concentrations.

DESIGN

Cross-sectional comparison in age- and BMI-matched nonobese volunteers with regular cycles (CO, n = 19) or in early postmenopause (EPM, n = 19), aged 40-52 years, and a young cycling group (CY, n = 21), aged 20-30 years.

MEASURES

Sex steroids, fasting AD, leptin, insulin, glucose, AD/leptin (A/L) ratio, and insulin resistance (IR) by homeostasis model assessment (HOMA-IR). In ovulatory women, AD, estradiol (E(2)), and progesterone were assessed weekly across the same menstrual cycle.

RESULTS

Insulin, glucose, HOMA-IR, A/L ratio, and leptin values were similar across the three study groups. AD differed, with the highest concentrations in the EPM group (CY: 13.0 +/- 0.9 microg/ml vs. CO: 14.0 +/- 1.1 microg/ml vs. EPM: 17.7 +/- 1.5 microg/ml; p = .05). Values among cycling women were similar. When the cycling groups were combined into a premenopausal (PRE) group and compared to EPM women by BMI (> or

CONCLUSION

Nonobese, midlife women experience minimal adverse effects from reproductive aging on insulin sensitivity and adipokine secretion. The menstrual cycle is not a key mediator of AD. Early menopause has differential, BMI-dependent effects on adipokine secretion.

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Key Words

• menopause
• menstrual cycle
• adipokines

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MESH Headings

• Adipokines/blood
• Adult
• Aging/blood
• Body Mass Index
• Female
• Humans
• Insulin Resistance
• Middle Aged
• Reproduction

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Grants

• P30 NR010677-03 NINR NIH HHS
• R01 AG015083-04 NIA NIH HHS
• P30 NR010677 NINR NIH HHS
• P30NR010677 NINR NIH HHS
• R01-AG15083-04 NIA NIH HHS
• 5-M01-00042 PHS HHS

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Affiliation(s)

Patricia A. Rouen McAuley School of Nursing, University of Detroit Mercy, 4001 W. McNichols Road., Detroit, MI 48221, , Phone: (313) 993-1739 Fax: (313) 993-1271
Jane L. Lukacs School of Nursing, University of Michigan, Ann Arbor, MI
Nancy E. Reame School of Nursing, Columbia University, New York, NY

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Comparison between several insulin sensitivity indices and metabolic risk factors in overweight and obese postmenopausal women: a MONET study

BACKGROUND AND AIMS

The purpose of this study was to compare the relationship of several insulin sensitivity indices with cardiometabolic risk factors in overweight and obese postmenopausal women.

METHODS AND RESULTS

This was a cross-sectional study involving 137 overweight and obese postmenopausal women (age: 57.7+/-4.8 yrs; body mass index: 32.4+/-4.6 kg/m(2); body fat: 38.6+/-9.2 kg). Insulin sensitivity was determined by the euglycaemic-hyperinsulinemic (EH) clamp technique as well as by oral glucose tolerance test (OGTT) derived indices (Stumvoll, Matsuda and SI(is)) and fasting surrogate indices (HOMA, QUICKI). Cardiometabolic risk factors included: body composition and visceral fat that were measured using dual energy X-ray absorptiometry and computed tomography, respectively. Peak oxygen consumption, lower body muscle strength (using weight training equipment), physical activity energy expenditure (doubly labeled water), plasma lipids and C-reactive protein were also measured. Correlations of insulin sensitivity indices with metabolic risk factors showed some similarities, however, a wide range of variations were also observed. Furthermore, our results showed that visceral fat was the primary predictor for surrogate and OGTT indices, explaining 15-28% of the variance and the triglycerides/HDL-C ratio was the primary predictor for the EH clamp indices, explaining 15-17% of the variance.

CONCLUSION

The present study indicates that the different methods of measuring and/or expressing insulin sensitivity display variations for associations with cardiometabolic risk factors. Therefore, interpretations of relationships between insulin sensitivity indices and cardiometabolic risk factors should take into account the method used to estimate and express insulin sensitivity.

The burden of cure: long-term side effects following hematopoietic stem cell transplantation (HSCT) in children

Children who survive hematopoietic stem cell transplantation (HSCT) are at risk for an inordinate number of long-term side effects. Late effects can be secondary to the underlying diagnosis for which the transplant is performed, prior treatment of the disease, the transplant preparative regimen, treatment of the complications of transplant, and immunologic interactions between the graft and the host. This article describes the risks and manifestations of the most commonly reported late effects in survivors of pediatric HSCT.

Metabolic syndrome and risk of venous thromboembolism: Longitudinal Investigation of Thromboembolism Etiology

SUMMARY BACKGROUND

In a recent case-control study, the odds of metabolic syndrome (MetSyn) among deep vein thrombosis cases were almost twice those among controls. We tested the hypothesis that the incidence of non-cancer-related venous thromboembolism (VTE) is higher among adults with MetSyn and further, that associations are stronger for idiopathic than secondary VTE.

METHODS

A total of 20 374 middle-aged and elderly adults were followed for over 12 years for incident VTE in the Longitudinal Investigation of Thromboembolism Etiology (LITE). All hospitalizations were identified and VTEs validated by chart review. Baseline MetSyn was defined using ATP III guidelines, including >or=3 of the following components: abdominal obesity, elevated blood pressure, low HDL-cholesterol, high triglycerides and high glucose. Because sex modified the relation between MetSyn and VTE (p(interaction) = 0.001), proportional hazards regression analyses were stratified by sex to assess the associations of MetSyn and its components with risk of incident non-cancer-related VTE, adjusting for potential confounders.

RESULTS

Incident VTE (n = 358) included 196 idiopathic events. Baseline MetSyn was associated with risk of total VTE (hazard ratio (HR) = 1.84, 95% CI = 1.30, 2.59) and idiopathic VTE (HR = 1.59, 95% CI = 1.02, 2.47) among men, but not women. The association was largely attributable to abdominal obesity (HR of VTE = 2.10, 95% CI = 1.51, 2.93, in men; HR of VTE = 1.70, 95% CI = 1.24, 2.34, in women), with no additional contribution by the other MetSyn components.

CONCLUSION

Although abdominal obesity was associated with increased risk of VTE in both men and women, MetSyn and its other components do not seem important in VTE etiology.

Cardiovascular complications in HIV management: past, present, and future

Highly active antiretroviral therapy (HAART) has significantly improved the prognosis for many individuals with HIV infection. Consequently, HIV infection has become a chronic and manageable disease. The focus on long-term management of patients with HIV infection has broadened to include comorbid conditions, most notably cardiovascular disease. Patients with HIV infection share many cardiovascular risk factors with the general population, and HIV infection itself may increase cardiovascular risk. Changes in lipid profiles associated with increased cardiovascular risk that have been observed with some HAART regimens have been a cause for concern among clinicians who treat HIV-infected patients. However, the lipid effects of HAART seem to depend on the type and duration of regimens employed. They can be managed effectively according to current guidelines that recommend lifestyle changes (eg, improved diet, increased exercise, smoking cessation) and pharmacologic therapy described in established treatment paradigms for patients on antiretroviral therapy and similar to measures currently used by the general population. A review of the clinical data indicates that the virologic and immunologic benefits of HAART clearly outweigh any metabolic effects observed in some patients over time and that preexisting, established cardiovascular risk factors contribute significantly to the potential development of cardiovascular events. These benefits of antiretroviral therapy have been demonstrated in studies comparing the superior efficacy of continuous vs. intermittent HAART.

Association of cardiorespiratory fitness with insulin sensitivity in overweight and obese postmenopausal women: a Montreal Ottawa New Emerging Team study

The purpose of this study was to examine the relation between insulin sensitivity and cardiorespiratory fitness in overweight and obese postmenopausal women. The study population consisted of 127 overweight and obese postmenopausal women (age, 57.7 +/- 4.8 years; body mass index, 32.7 +/- 4.7 kg/m(2)). Subjects were classified by dividing the entire cohort into tertiles (T) based on insulin sensitivity expressed per kilograms of lean body mass (LBM) (T1, <10.9; T2, 10.9-12.9, T3, >12.9 mg/min per kilogram of LBM, respectively). Outcome measures were body composition (dual-energy x-ray absorptiometry), visceral adipose tissue (computed tomography), insulin sensitivity (hyperinsulinemic-euglycemic clamp), cardiorespiratory fitness (indirect calorimetry), lower-body muscle strength (1 maximal repetition), physical activity energy expenditure (doubly labeled water), fasting lipids, and inflammatory profile. We found a significant positive relationship between insulin sensitivity and cardiorespiratory fitness (r = 0.25, P = .005). Moreover, cardiorespiratory fitness was higher in the T3 group compared to the T1 group (36.2 +/- 6.1 vs 33.1 +/- 5.0 mL/kg LBM per minute, respectively; P = .028). However, the difference was no longer significant after controlling for visceral adipose tissue or muscle strength. Finally, cardiorespiratory fitness was an independent predictor of insulin sensitivity. High levels of cardiorespiratory fitness are associated with higher levels of insulin sensitivity in overweight and obese postmenopausal women. Moreover, visceral adipose tissue accumulation or muscle strength may be potential mediators of this relationship.

Fructose-induced hypertension: essential role of chloride and fructose absorbing transporters PAT1 and Glut5

Increased dietary fructose in rodents recapitulates many aspects of the Metabolic Syndrome with hypertension, insulin resistance and dyslipidemia. Here we show that fructose increased jejunal NaCl and water absorption which was significantly decreased in mice whose apical chloride/base exchanger Slc26a6 (PAT1, CFEX) was knocked out. Increased dietary fructose intake enhanced expression of this transporter as well as the fructose-absorbing transporter Slc2a5 (Glut5) in the small intestine of wild type mice. Fructose feeding decreased salt excretion by the kidney and resulted in hypertension, a response almost abolished in the knockout mice. In parallel studies, a chloride-free diet blocked fructose-induced hypertension in Sprague Dawley rats. Serum uric acid remained unchanged in animals on increased fructose intake with hypertension. We suggest that fructose-induced hypertension is likely caused by increased salt absorption by the intestine and kidney and the transporters Slc26a6 and Slc2a5 are essential in this process.

Comparison of oxygenation in peripheral muscle during submaximal aerobic exercise, in persons with COPD and healthy, matched-control persons

OBJECTIVE

The purpose of this study was to compare peripheral muscle oxygenation in persons with chronic obstructive pulmonary disease (COPD) to healthy control persons, during submaximal exercise.

METHODS

Eight persons with COPD (forced expiratory volume in one second [FEV1] = 1.00 +/- 0.27 L) and eight healthy control persons (FEV, = 1.88 +/- 0.55L) performed a submaximal graded exercise test (GXT), and completed 4 min of constant load exercise (CON) at 50% of peak GXT. Measurements included oxygen uptake, heart rate, arterial oxygen saturation and peripheral muscle oxygenation (%StO2) at rest, during exercise, and recovery.

RESULTS

Significantly greater workloads were attained for controls compared with COPD for peak GXT and CON. No significant differences in %StO2 were observed between groups at: rest (GXT: 29.5 +/- 22.8 vs 30.4 +/- 17.3%; CON: 33.3 +/- 15.4 vs 35.1 +/- 17.2%); peak GXT (29.4 +/- 19.4 vs 26.5 +/- 15.9%); 4 min of CON (25.9 +/- 13.5 vs 34.5 +/- 21.8%); and recovery (GXT: 46.6 +/- 29.1 vs 44.3 +/- 21.7%; CON: 40.9 +/- 21.5 vs 44.5 +/- 23.2%).

CONCLUSION

These results suggest that peripheral skeletal muscle oxygenation is not compromised in COPD during submaximal exercise, and limitations in exercise capacity are most likely a result of muscle disuse and poor lung function.