Pathophysiology and Long-Term Management of the Metabolic Syndrome

Lignans' Potential in Pre and Post-onset Type 2 Diabetes Management

INTRODUCTION

Type 2 Diabetes (T2D) cases continue to rise dramatically despite efforts to get people to exercise and eat with a view to health and combatting the cluster of 7 issues (central obesity (elevated waist circumference), hyperglycaemia, hypertension, dyslipidemia, pro-thrombotic state, increased oxidation (including Low-density Lipoprotein (LDL)) and the pro-inflammatory state associated with pre- and post-onset T2D.

BACKGROUND

There are numerous medications available to deal with these seven major issues. However, each medication currently available manages a maximum of two cluster members at a time. Consequently, polypharmacy is frequently required to manage the cluster of seven. Polypharmacy brings with it high financial costs for numerous medications, the risk of poor compliance (particularly so in older patients), side effects and drug interactions. Thus, there is a search for new agents that reduce the high costs and risks of polypharmacy while at the same time combatting three or more of the cluster of seven. There is very limited evidence to suggest that one or more lignans may efficaciously and safely, in the short and long term, manage at least three of the cluster of seven, pre- and post-T2D onset, thus reducing polypharmacy. However, multi-centre, large clinical trials are required before any definitive conclusions about these lignans can be reached regarding their safe and efficacious polypharmacy reduction potential, both long and short-term, in pre and post-onset T2D management.

CONCLUSION

It is concluded that some lignans appear to have the potential to manage at least three members of the cluster of seven in pre- or post-T2D onset and hence reduce polypharmacy but much more investigation is required to confirm if such is the case. At the moment, there is not enough evidence that any of the lignans will, in the long or short term, safely and efficaciously manage the cluster of seven via polypharmacy reduction.

Polyphenol-Rich Dry Common Beans (Phaseolus vulgaris L.) and Their Health Benefits

Polyphenols are plant metabolites with potent anti-oxidant properties, which help to reduce the effects of oxidative stress-induced dreaded diseases. The evidence demonstrated that dietary polyphenols are of emerging increasing scientific interest due to their role in the prevention of degenerative diseases in humans. Possible health beneficial effects of polyphenols are based on the human consumption and their bioavailability. Common beans (Phaseolus vulgaris L.) are a greater source of polyphenolic compounds with numerous health promoting properties. Polyphenol-rich dry common beans have potential effects on human health, and possess anti-oxidant, anti-diabetic, anti-obesity, anti-inflammatory and anti-mutagenic and anti-carcinogenic properties. Based on the studies, the current comprehensive review aims to provide up-to-date information on the nutritional compositions and health-promoting effect of polyphenol-rich common beans, which help to explore their therapeutic values for future clinical studies. Investigation of common beans and their impacts on human health were obtained from various library databases and electronic searches (Science Direct PubMed, and Google Scholar).

Nutritional and health perspectives of beans (Phaseolus vulgaris L.): an overview

Beans, the variants of Phaseolus vulagris, are nutritionally and economically important food crop in each part of the world. Besides providing nutrients such as multifaceted carbohydrates, elevated proteins, dietary fiber, minerals, and vitamins, these also contain rich variety of polyphenolic compounds with prospective health benefits. This review mainly focuses the important nutritional aspects of beans as well as their contribution in decreasing the risks of chronically degenerative diseases.

Circadian clock desynchronisation and metabolic syndrome

There is emerging evidence in the literature to suggest that disruption of the normal circadian rhythm (sleep-wake cycle signalling) is a potential risk factor to explain the increased incidence of metabolic syndrome. Over the last century, obesity, diabetes and other components of metabolic syndrome have been on the rise. On the other hand, the amount of sleep has decreased from an average of 6-8 h per night. Furthermore, the quality of sleep has declined with more individuals voluntarily decreasing their amount of sleep to work or enjoy leisure activities. Over the last decade, researchers have examined the relationship between disruption in human circadian system and the emergence of symptoms related to metabolic syndrome. Indeed, epidemiological studies suggest a relation between sleep duration and diabetes and obesity. Moreover, experimental animal and human studies suggest such a relation. These studies propose optimum sleep duration of 7-8 h per night to avoid circadian rhythm disruption and suggest that sleep disturbance, whether iatrogenic or disease-related, should be considered as a risk factor for metabolic syndrome, and be addressed. This field is in its infancy and further understanding of specific pathophysiological pathways of circadian desynchronisation will help in developing novel preventive and therapeutic strategies.

Hydrodynamic delivery of mIL10 gene protects mice from high-fat diet-induced obesity and glucose intolerance

High-fat diet (HFD) induced obesity is associated with low-grade inflammation, insulin resistance (IR), and glucose intolerance. The objective of this study is to assess the effect of interleukin 10 (IL10), an anti-inflammatory cytokine, on blocking HFD-induced obesity and obesity-associated metabolic disorders by hydrodynamic delivery of IL10-containing plasmid. Animals fed a regular chow or HFD received two injections (one on day 1 and the other on day 31) of plasmids containing green fluorescence protein (GFP) or mouse IL10 (mIL10) gene. Blood concentration of mIL10 reached ~200 ng/ml on day 7 in animals receiving mIL10 plasmid DNA. The transfection efficiency of liver cells was the same in animals fed a regular chow or HFD. No difference was seen in animals on regular chow when injected with plasmids containing either gfp or mIL10 gene. Overexpression of mIL10 prevented weight gain of animals on HFD. Intraperitoneal glucose tolerance test (IPGTT) and insulin tolerance tests (ITT) showed that mIL10 maintained insulin sensitivity and prevented glucose intolerance. The mechanistic study reveals that mIL10 suppressed macrophage infiltration and reduced the development of crown-like structures in adipose tissue (AT). Collectively, these results suggest that maintaining a higher level of IL10 through gene transfer could be an effective strategy in preventing diet-induced obesity.

BMI and headache among women: results from 11 epidemiologic datasets

OBJECTIVE

To evaluate the association between BMI (kg/m(2)) and headaches among women.

METHODS AND PROCEDURES

Cross-sectional analysis of 11 datasets identified after searching for all large publicly available epidemiologic cohort study datasets containing relevant variables. Datasets included National Health Interview Survey (NHIS): 1997-2003, the first National Health Examination and Nutrition Survey, Alameda County Health Study (ACHS), Tecumseh Community Health Study (TCHS), and Women's Health Initiative (WHI). The women (220,370 in total) were aged 18 years or older and had reported their headache or migraine status.

RESULTS

Using nonlinear regression techniques and models adjusted for age, race, and smoking, we found that increased BMI was generally associated with increased likelihood of headache or severe headache among women. A BMI of approximately 20 was associated with the lowest risk of headache. Relative to a BMI of 20, mild obesity (BMI of 30) was associated with roughly a 35% increase in the odds for experiencing headache whereas severe obesity (BMI of 40) was associated with roughly an 80% increase in odds. Results were essentially unchanged when models were further adjusted for socioeconomic variables, alcohol consumption, and hypertension. Being diagnosed with migraine showed no association with BMI.

DISCUSSION

Among US women, a BMI of approximately 20 (about the 5th percentile) was associated with the lowest likelihood of headache. Consistently across studies, obese women had significantly increased risk for headache. By contrast, the risk for diagnosed migraine headache per se was not obviously related to BMI. The direction of causation and mechanisms of action remain to be determined.

Impact of interleukin 6 -174G>C polymorphism on obesity-related metabolic disorders in people with excess in body weight

Low-grade inflammation has been related to obesity, insulin resistance, and related metabolic disorders. In this context, the -174G>C gene polymorphism of the proinflammatory interleukin 6 (IL-6) cytokine has also been associated with these diseases. Based on this, the aim of the current study was to evaluate the role of IL-6 -174G>C polymorphism in the risk of developing metabolic alterations in people with excessive body weight. One hundred six Caucasian volunteers (body mass index, 33.2 +/- 5.3 kg/m(2)) were recruited to assess the potential relationship between carrying the -174G>C polymorphism and the risk of developing obesity-related metabolic disorders, such as hypertension, atherogenic dyslipidemia, and insulin resistance evaluated by the homeostasis model assessment of insulin resistance index. Subjects carrying the C allele showed higher plasma insulin concentrations and systolic blood pressure than homozygotes for the G allele. A multiple regression analysis showed that the presence of the C allele induced an increase in the homeostasis model assessment of insulin resistance index as compared with GG subjects (adjusted R(2) = .26, P < .001). Analyzing the mentioned obesity-related diseases, an enhanced prevalence of presenting high risk of developing these complications was found for the GC and CC genotypes relative to GG, with an adjusted odds ratio of 5.2 (P = .003). This association remained significant after controlling for multiple comparisons by the 10,000-permutation test (P = .004838). These data demonstrate that the occurrence of C allele of IL-6 -174 G>C gene polymorphism in people with excessive body weight is accompanying a higher risk of developing obesity-related metabolic disorders, especially insulin resistance.

Pinto bean consumption changes SCFA profiles in fecal fermentations, bacterial populations of the lower bowel, and lipid profiles in blood of humans

Beans improve serum lipids and may reduce the risk of colon cancer by increasing colonic SCFA formation. We assessed whether pinto bean consumption affects in vitro fecal bacterial fermentation and production of SCFA, colonic bacterial populations, and serum lipids. Adults grouped as premetabolic syndrome (pre-MetSyn) (n = 40) or controls (n = 40) were randomly assigned to consume either a bean entrée [1/2 cup (130 g) of dried, cooked pinto beans] or an isocaloric chicken soup entrée daily for 12 wk. Measurements included in vitro fecal fermentation of various resistant starch substrates, fecal bacterial speciation, and blood lipids. When expressed as a difference between baseline and treatment, propionate production from fecal material fermented in vitro with bean flour was higher (P < 0.02) in volunteers consuming beans than in those consuming soup. During the treatment period alone, bean consumption did not affect propionic acid production with any substrate but lowered (P < 0.02) butyric acid production when cornstarch was the substrate. In all volunteers, bean consumption decreased fecal production of isovaleric (P < 0.05) and isobutyric (P < 0.002) acids from cornstarch by as much as 50%. Of the bacterial populations tested, only Eubacterium limosum was affected by bean consumption and was approximately 50% lower than in those consuming soup. Beans lowered serum total cholesterol (P < 0.014) by approximately 8% in the controls and 4% in the pre-MetSyn group. Bean consumption lowered serum HDL-cholesterol (P < 0.05) and LDL-cholesterol (P < 0.05) in both groups without affecting serum triglycerides, VLDL cholesterol, or glucose. This study provides evidence that bean consumption can improve lipid profiles associated with cardiovascular disease, but does not clearly confer health benefits related to colon cancer risk.

The Role of Consumption of Alpha-Linolenic, Eicosapentaenoic and Docosahexaenoic Acids in Human Metabolic Syndrome and Type 2 Diabetes- A Mini-Review

The human metabolic syndrome and its frequent sequela, type 2 diabetes are epidemic around the world. Alpha-linolenic acid (ALA, 18:3 n-3), eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic acid (DHA, 22:6 n-3) consumption ameliorates some of these epidemics' features thus leading one to question if consumption of EPA and DHA, and their metabolic precursor ALA reduce the conversion of metabolic syndrome to type 2 diabetes and reduce the major cause of death in the metabolic syndrome and type 2 diabetes-myocardial infarction. Contributing to myocardial infarction are metabolic syndrome's features of dyslipidemia (including elevated total cholesterol and LDL-c), oxidation, inflammation, hypertension, glucose intolerance, overweight and obesity. Inflammation, glucose and lipid levels are variously influenced by disturbances in various adipocytokines which are in turn positively impacted by n-3 polyunsaturated fatty acid consumption. Type 2 diabetes has all these features though elevated total cholesterol and LDL-c are rarer. It is concluded that EPA and DHA consumption significantly benefits metabolic syndrome and type 2 diabetes primarily in terms of dyslipidemia (particularly hypertriglyceridemia) and platelet aggregation with their impact on blood pressure, glucose control, inflammation and oxidation being less established. There is some evidence that EPA and/or DHA consumption, but no published evidence that ALA reduces conversion of metabolic syndrome to type 2 diabetes and reduces death rates due to metabolic syndrome and type 2 diabetes. ALA's only published significance appears to be platelet aggregation reduction in type 2 diabetes.

Mesenteric fat thickness as an independent determinant of fatty liver

OBJECTIVE

Mesenteric fat is drained by the portal circulation and has been suggested to be a key component in obesity-related health risk, notably the metabolic syndrome. There are increasing epidemiological and experimental data showing that fatty liver is another component of this multifaceted syndrome. Given their intimate anatomical and physiological relationships, we hypothesized that mesenteric fat thickness may be independently associated with the risk of fatty liver. To test this hypothesis, we examined the predictive role of various fat deposits including mesenteric fat thickness, and various metabolic variables on the risk of fatty liver.

SUBJECTS AND METHODS

A total of 291 Chinese subjects (134 men and 157 women with a mean BMI of 23.7 kg/m2, range: 16.5-33.4 kg/m2) underwent ultrasound examination for measurement of mesenteric, subcutaneous and preperitoneal fat thickness, and for diagnosis of fatty liver. Body mass index, waist circumference, and waist-hip ratio were recorded. Blood pressure was measured. Fasting plasma glucose, insulin resistance, high-density lipoprotein cholesterol (HDL-C), triglycerides, low-density lipoprotein cholesterol (LDL-C), liver enzymes were determined by common methods.

RESULTS

The subjects with fatty liver had greater abdominal fat thickness and higher anthropometric indexes than those without fatty liver. The subjects with fatty liver also showed higher blood pressure, worse lipid and glycaemic profile compared with those without fatty liver. Using multiple logistic regression analysis, mesenteric fat thickness was a risk factor of fatty liver, independent of body mass index, age, sex, insulin resistance, fasting plasma glucose, lipid and blood pressure. The odds ratio was 1.5 (95% confidence interval: 1.27-1.77) for every 1 mm increase in the mesenteric fat thickness. Measurement of preperitoneal and subcutaneous fat deposits did not show significant associations with fatty liver.

CONCLUSION

Mesenteric fat thickness measured on ultrasound is an independent determinant of fatty liver.

Inhibitory effects of cardiotonic pills on platelet function in dogs fed a high-fat diet

Insulin resistance and the consequent metabolic disorders are associated with a state of platelet hyperactivity. Oxidative stress is responsible for the persistent platelet activation. We sought to study the inhibitory effect of cardiotonic pills, an oral herbal component, on platelet function in a dog model with insulin resistance induced by high-fat feeding. We fed 18 dogs with a high-fat diet and six dogs with normal chow as control for 6 months. Then, six dogs were fed with a high-fat diet and received additional aspirin (250 mg/day), and another six dogs received additional cardiotonic pills (1,000 mg/day) for 4 months. Time-course changes in metabolic parameters and platelet function were detected. After high-fat feeding for 6 months, 18 dogs developed a series of metabolic disorders including obesity, dyslipidemia, oxidative stress and insulin resistance. In addition, a platelet hyperactivity state, characterized by increased agonist (arachidonic acid, ADP and collagen) induced platelet aggregation, platelet expression of adhesion molecules (P-selectin and GP IIb/IIIa), and platelet intracellular calcium concentration, was indicated. Cardiotonic pills showed a significant antioxidative activity by presenting an increase in plasma superoxide dismutase and decrease in erythrocyte glutathione, as well as a lipid-lowering effect (decrease in both plasma cholesterol and triglyceride). Either aspirin or cardiotonic pills could significantly reverse the platelet hypersensitivity and hyperfunction. Compared with aspirin, cardiotonic pills showed a more exaggerated inhibitory effect on platelet function (a significantly decreased collagen-stimulated platelet aggregation, and expression of adhesion molecules). In conclusion, cardiotonic pills inhibited platelet hyperfunction in dogs with insulin resistance. This inhibitory effect may mainly be explained by antioxidative activity and metabolic control.

Low-carbohydrate or low-fat diets for the metabolic syndrome?

This report discusses a variety of considerations and reviews recent clinical trial data relevant to the question of which dietary approach is optimal for treatment and prevention of the metabolic syndrome. Special emphasis is given to the question of whether the degree to which metabolic syndrome features are observed in an individual patient should correspond to the degree to which carbohydrate restriction should be recommended. Short-term metabolic studies lend support to this concept, but longer-term effectiveness trials suggest the degree of dietary adherence and associated weight losses, rather than diet type, are the key predictors of metabolic cardiac risk factor reduction.

The Metabolic Syndrome: Recognition and Management

The National Cholesterol Education Program defines the metabolic syndrome as three or more of five abnormalities: waist circumference of >40 in (102 cm) for men or >35 in (88 cm) for women, triglyceride level of > or =150 mg/dL, high-density lipoprotein cholesterol of <40 mg/dL in men or <50 mg/dL in women, blood pressure of > or =130 or > or =85 mm Hg, and fasting glucose of > or =110 mg/dL. It is related to insulin resistance, but the two terms are not synonymous. Both are associated strongly with obesity. The metabolic syndrome is important as an indicator of increased risk of cardiovascular disease (CVD) in patients with and without clinical CVD. The CVD risk of the metabolic syndrome is greater than that conferred by any single CVD risk factor. Since risk factors tend to cluster, if one component of the metabolic syndrome is present, one should assess for other risk factors. The metabolic syndrome is also predictive of new-onset type 2 diabetes. Early diagnosis provides justification for measures that can improve components of the syndrome and reduce CVD risk. The management strategy for metabolic syndrome focuses on overall CVD risk rather than single risk factors; effective therapy includes priority for weight reduction and increased physical activity. Pharmacotherapy is typically needed for control of high blood pressure, hypercoagulability, and increased levels of blood glucose and triglycerides.

Diagnosis and management of the metabolic syndrome in obesity

The metabolic syndrome is a constellation of interrelated abnormalities that increase the risk for cardiovascular disease and progression to type 2 diabetes. The prevalence of this syndrome is increasing because of the 'obesity epidemic'. The National Cholesterol Education Program Adult Treatment Panel III defined practical criteria for the diagnosis of the metabolic syndrome and established the basic principles for its management. Also, the International Diabetes Federation recently proposed another definition. The metabolic syndrome is a secondary target for cardiovascular risk reduction. Clinicians should identify individuals with this condition, assess their cardiovascular risk and treat them by an aggressive and multifaceted approach. The most effective therapeutic intervention in patients with the metabolic syndrome should focus on modest weight reduction and regular physical activity. Adoption of a healthier diet and smoking cessation are necessary. Drug therapy may be needed to achieve recommended goals if therapeutic lifestyle changes are not sufficient. Low-density lipoprotein cholesterol is the primary target of therapy (new aggressive goals should be achieved). Statins are probably the drugs of choice. Fibrates and nicotinic acid are also useful options. Hypertension should be managed aggressively probably starting with an inhibitor of the renin-angiotensin system or a calcium channel blocker and adding a low dose of a thiazide diuretic if necessary. Aspirin should be administered if the cardiovascular risk is high. In the future acarbose, metformin, meglitinides and thiazolidinediones may be used in patients with the metabolic syndrome to delay the onset of type 2 diabetes and reduce cardiovascular risk. Such an intense and multifactorial approach is likely to reverse the bad prognosis associated with the metabolic syndrome.

Insulin resistance: sex matters

PURPOSE OF REVIEW

This review summarizes recent advances in our understanding of the differences between the sexes in relation to insulin resistance. Alterations in the body's sensitivity to insulin cause a series of metabolic abnormalities representing essentially the metabolic syndrome (i.e. high fasting plasma triglyceride and glucose and low HDL-cholesterol concentrations, hypertension, abdominal obesity) and type 2 diabetes. Although our knowledge of the causes and consequences of impairments in the insulin signaling pathway at the metabolic, cellular and molecular level has progressed rapidly and continues to do so, serious attempts to discover whether and how sex affects the metabolic control by insulin has only recently started to evolve.

RECENT FINDINGS

The most significant recent findings include data that suggest that females are intrinsically more insulin resistant than males, possibly because of specific sex-linked gene expression and the resulting differences in metabolic control elements (e.g. signaling pathway and substrate shuttling elements, receptors). Sex hormones, environmental and life-style factors augment or improve the female 'genetic' disadvantage, in ways that are possibly also genetically predetermined.

SUMMARY

Women are distinctly different to men with regard to the actions of insulin, the susceptibility to develop insulin resistance, and the response to stimuli that are known to enhance or impair sensitivity to the effects of insulin. Therefore, sex has to be considered when investigating insulin action, metabolic pathways known to be affected by the actions of insulin and diseases that result from abnormalities in insulin action and their treatment.