Prevalence of insulin resistance and the metabolic syndrome with alternative definitions of impaired fasting glucose

Nutraceutical approaches to metabolic syndrome

Metabolic Syndrome (MetS), affecting at least 30% of adults in the Western World, is characterized by three out of five variables, from high triglycerides, to elevated waist circumference and blood pressure. MetS is not characterized by elevated cholesterolemia, but is rather the consequence of a complex interaction of factors generally leading to increased insulin resistance. Drug treatments are of difficult handling, whereas well-characterized nutraceuticals may offer an effective alternative. Among these, functional foods, e.g. plant proteins, have been shown to improve insulin resistance and reduce triglyceride secretion. Pro- and pre-biotics, that are able to modify intestinal microbiome, reduce absorption of specific nutrients and improve the metabolic handling of energy-rich foods. Finally, specific nutraceuticals have proven to be of benefit, in particular, red-yeast rice, berberine, curcumin as well as vitamin D. All these can improve lipid handling by the liver as well as ameliorate insulin resistance. While lifestyle approaches, such as with the Mediterranean diet, may prove to be too complex for the single patient, better knowledge of selected nutraceuticals and more appropriate formulations leading to improved bioavailability will certainly widen the use of these agents, already in large use for the management of these very frequent patient groups. Key messages Functional foods, e.g. plant proteins, improve insulin resistance. Pro- and pre-biotics improve the metabolic handling of energy-rich foods. Nutraceutical can offer a significant help in handling MetS patients being part of lifestyle recommendations.

Adipose tissue dysfunction and its effects on tumor metabolism

Growing by an alarming rate in the Western world, obesity has become a condition associated with a multitude of diseases such as diabetes, metabolic syndrome and various cancers. Generally viewed as an abnormal accumulation of hypertrophied adipocytes, obesity is also a poor prognostic factor for recurrence and chemoresistance in cancer patients. With more than two-thirds of the adult population in the United States considered clinically overweight or obese, it is critical that the relationship between obesity and cancer is further emphasized and elucidated. Adipocytes are highly metabolically active cells, which, through release of adipokines and cytokines and activation of endocrine and paracrine pathways, affect processes in neighboring and distant cells, altering their normal homeostasis. This work will examine specifically how adipocyte-derived factors regulate the cellular metabolism of malignant cells within the tumor niche. Briefly, tumor cells undergo metabolic pressure towards a more glycolytic and hypoxic state through a variety of metabolic regulators and signaling pathways, i.e., phosphoinositol-3 kinase (PI3K), hypoxia-inducible factor-1 alpha (HIF-1α), and c-MYC signaling. Enhanced glycolysis and high lactate production are hallmarks of tumor progression largely because of a process known as the Warburg effect. Herein, we review the latest literature pertaining to the body of work on the interactions between adipose and tumor cells, and underlining the changes in cancer cell metabolism that have been targeted by the currently available treatments.

A comprehensive review of metabolic syndrome affecting erectile dysfunction

INTRODUCTION

Metabolic syndrome (MetS) is the most important public health issue threatening the health of men and women all over the world. Its current prevalence (i.e., approximately 30%) is continuously increasing. MetS by itself is considered a risk factor for erectile dysfunction (ED).

AIM

To focus on the definition epidemiology, pathogenesis, and possible mechanistic links between MetS and ED in order to provide guidelines for treating such individuals.

METHODS

The search strategies yielded total records screened from PubMed.

MAIN OUTCOME MEASURES

Regardless of the definition, MetS consists of insulin resistance, hypertension, dyslipidemia, and obesity. MetS is not an end disease but is a disorder of energy utilization and storage.

RESULTS

The prevalence of ED in patients with MetS is almost twice than in those without MetS, and about 40% of patients with ED have MetS. An important mechanism linking MetS and ED is hypogonadism.

CONCLUSIONS

Recognizing through ED, underlying conditions such as hypogonadism, diabetes and MetS might be a useful motivation for men to improve their health-related choices. The clinical management of MetS can be done by therapeutic interventions that include lifestyle modifications, hormone replacement alone or in combination with phosphodiesterase 5 inhibitors, and other pharmacological treatments.

Sexual function in male patients with metabolic syndrome and effective parameters on erectile dysfunction

PURPOSE

We aimed to investigate the relationship between metabolic syndrome and sexual function and effective parameters on erectile dysfunction (ED).

MATERIALS AND METHODS

A total of 1300 individuals were included in this study betwe¬en January 2009 and July 2012. All of individuals were asked to fill in an International Index for Erectile Function (IIEF) questionnaire. The presence of metabolic syndrome was determined when any three or more of the five risk factors were present according to the National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP)-III. Obese individuals were divided into six groups according to modified World Health Organization (WHO) definition. Effective parameters on erectile dysfunction were investigated in individuals with metabolic syndrome.

RESULTS

Metabolic syndrome was detected in 455 individuals (35%). Mean domain scores of IIEF for all parameters were higher in individuals without metabolic syndrome than individuals with metabolic syndrome (p < 0.05). Mean domain scores of IIEF were lower in individuals with class 3 obesity than individuals with other obese groups (p < 0.05) for erectile dysfunction. There was statistical difference in terms of mean score of IIEF-Erectile function between smoking and nonsmoking groups (p < 0.05). Seventy percent of individuals with metabolic syndrome and 45% of individuals without metabolic syndrome had ED (p < 0.001). Logistic regression analysis revealed that waist circumference (WC) was the most important criteria for ED (p < 0.05).

CONCLUSIONS

Metabolic syndrome, smoking and obesity seem to be potential risk factors for ED. We recommend individuals with metabolic syndrome, smoking and obesity should be questioned about ED.

Is alanine aminotransferase associated with osteopenia in middle-aged and elderly Chinese?

OBJECTIVE

To investigate the association between alanine aminotransferase (ALT) levels and risk of osteopenia in middle-aged and elderly Chinese with ALT within the normal range.

METHODS

This was a cross-sectional study. A total of 4,890 men and women (pre- and postmenopausal) aged 40 years or older were randomly recruited from Fujian, China. Each participant was required to complete a questionnaire and then undergo anthropometric, biochemical, and bone mineral density measurements.

RESULTS

The odds ratio of osteopenia decreased significantly with increasing ALT level at baseline. The three groups (men, pre- and postmenopausal women) were divided by ALT quartiles. In multiple logistic regression models using the first quartile as the reference, after adjusting for corresponding confounding factors, the odds ratios of osteopenia across the other ALT quartiles were 0.576 (95% confidence interval [CI], 0.390 to 0.851), 0.654 (95% CI, 0.460 to 0.930), and 0.629 (95% CI, 0.427 to 0.926) for premenopausal women, and 0.949 (95% CI, 0.699 to 1.289), 0.733 (95% CI, 0.540 to 0.995), and 0.692 (95% CI, 0.508 to 0.943) for postmenopausal women (not significant for quartile 2). However, no significantly different results were found in men. Multiple linear regression models showed that serum ALT concentrations were positively associated with the homeostasis model assessment of insulin resistance.

CONCLUSION

Our study of middle-aged and elderly Chinese men and women demonstrates that the prevalence of osteopenia is inversely associated with ALT level when ALT is within the normal range.

Assessment of cardiovascular disease risk in patients with schizophrenia spectrum disorders in German psychiatric hospitals: results of the pharmacoepidemiologic CATS study

PURPOSE

Patients with severe mental illness are at high risk for metabolic and cardiac disorders. Thus, monitoring of cardiovascular risks is imperative and schedules for screening for lipids, glucose, body mass index (BMI), waist-hip ratio and blood pressure have been developed. We intended to analyze screening for metabolic disorders in German patients with schizophrenia spectrum disorders in routine psychiatric care.

METHODS

We included 674 patients with any F2 diagnosis in out- and inpatient settings and analyzed metabolic screening procedures as practiced under conditions of usual care.

RESULTS

Except BMI (54 %), all other values were documented only in a minority of patients: waist circumference (23 %), cholesterol (28 %), fasting glucose (19 %), triglycerides (25 %) and blood pressure (37 %). We found evidence for less than perfect quality of blood pressure measures. The group of patients who met the individual metabolic syndrome ATP III criteria was comparable to the US CATIE trial.

CONCLUSIONS

We conclude that frequency and quality of metabolic monitoring in German in- and outpatients settings are not in accordance with the respective recommendations. Similar to previous reports we found evidence for a high prevalence of metabolic disturbances in German patients with schizophrenia spectrum disorders.

Occurrence of erectile dysfunction, testosterone deficiency syndrome and metabolic syndrome in patients with abdominal obesity. Where is a sufficient level of testosterone?

AIM

The aim of this study was to determine the prevalence of erectile dysfunction (ED), testosterone deficiency syndrome (TDS), and metabolic syndrome in patients with abdominal obesity (AO) and the prevalence of morbidity at different levels of testosterone (TST).

BACKGROUND

Male sex hormones play an important role in ED and variety of TDS and may have influence on the development of metabolic syndrome. The number of men with AO which constitutes a serious health risk is continuously growing. Currently, there are different views that TST levels are already insufficient, and the patient should benefit from treatment.

OBJECTIVES

This study examined the association between ED, testosterone level and metabolic syndrome in men with AO.

DESIGN, SETTING, AND PARTICIPANTS

The study was carried out in an outpatient urology center of Urology Clinic and Obesity Center of the Clinic of Internal Medicine. There were 167 participants—men with AO which were examined as part of preventive examination.

METHODS

Hormonal, a complete urological and internal evaluation was carried out in every patient.

RESULTS AND LIMITATIONS

We found some degree of ED in 73% (122/167) in men with AO. The TST levels below 14 nmol/l had of these 122 patients 84 patients (68.9%) and 49 patients (40.2%) below 10 nmol/l. In this group of patients, we found 103/167 patients (61.7%) with metabolic syndrome. When we compared TST level and morbidity, we found significantly more patients with diabetes mellitus (DM), hypertension and dyslipidemia in group with TST below 10 nmol/l. We also found difference in the levels of HDL cholesterol and triglycerides in the group of patients with TST 10–14 and over 14 nmol/l.

CONCLUSION

Patients over 40 years of age with AO and ED should also be examined for TDS and metabolic syndrome. In this group of patients we found that 113/167 patients (67.6%) had total TST below 14 nmol/l, and sufficient level of TST seems to be above this level.

Association between metabolic syndrome and periodontal disease

BACKGROUND

Metabolic syndrome has been suggested as a potential risk factor for periodontal disease. Data based on NHANES III, with 7431 subjects aged 20 years or older, were analysed to confirm the association between metabolic syndrome and periodontal disease, and identify which components of metabolic syndrome might play a role in this association.

METHODS

Clinical criteria for metabolic syndrome included: (1) abdominal obesity; (2) increased triglycerides; (3) decreased HDL cholesterol; (4) hypertension or current use of hypertension medication; and (5) high fasting plasma glucose. Periodontal disease was evaluated by probing pocket depth (PPD) and was defined as mean PPD≥2.5 mm.

RESULTS

Women with two or more metabolic components had significantly increased odds of having periodontal disease as compared to those with no component [(two components, OR=5.6 (95% CI: 2.2-14.4); three or more, OR=4.7 (2.0-11.2)]. Using the definition of metabolic syndrome as having three to five metabolic components (reference group with <3 components), the adjusted odds ratios were 1.0 (0.7-1.6) for men and 2.1 (1.2-3.7) for women. Abdominal obesity was the largest contributory factor in both genders.

CONCLUSIONS

While the association between metabolic syndrome and periodontal disease was particularly significant for women, abdominal obesity appeared to be the contributing metabolic factor for both genders.

Racial differences in risk of prostate cancer associated with metabolic syndrome

OBJECTIVES

To perform a case-control study to test the association between metabolic syndrome features and prostate cancer. The metabolic syndrome refers to a cluster of conditions serving as risk factors for cardiovascular disease. The metabolic syndrome is prevalent in the United States, and the spectrum of specific features has been shown to differ by race and ethnicity. A number of recent reports have linked metabolic syndrome to prostate cancer; however, most studies have not had racially diverse populations to explore differences in risk.

METHODS

A case-control study was conducted to test the association between metabolic syndrome features and prostate cancer among 637 patients and 244 controls, with African-American men constituting 43% of the study population.

RESULTS

Metabolic syndrome, defined using a modified version of the Adult Treatment Panel III criteria, was marginally associated with an increased risk of prostate cancer in African-American men (odds ratio [OR] 1.71, 95% confidence interval [CI] 0.97-3.01), but not in white men (OR 1.02, 95% CI 0.64-1.62). After stratifying the patients by stage at diagnosis, African-American men with organ-confined disease were more likely to have a history of metabolic syndrome than were the controls (OR 1.82; 95% CI 1.02-3.23), but no association was observed among those with advanced-stage disease (OR 0.93; 95% CI 0.31-2.77). When evaluating the specific features of the metabolic syndrome, obesity was inversely related to prostate cancer among white men (OR 0.51, 95% CI 0.33-0.80) but unrelated to risk among African-American men (OR 1.15, 95% CI 0.70-1.89).

CONCLUSIONS

In the present investigation, the metabolic syndrome was associated with prostate cancer risk in African-American men, but not in white men. The prevalence of this syndrome, coupled with the racial disparity in prostate cancer incidence and outcomes after diagnosis, warrant additional investigation.

The metabolic syndrome and schizophrenia

OBJECTIVE

To summarize the accumulated data on metabolic syndrome prevalence in patients with schizophrenia, examine evidence for a biological contribution of the mental illness to metabolic risk and review novel options available for management of prediabetic states.

METHOD

A Medline search using metabolic syndrome, insulin resistance and insulin sensitivity cross-referenced with schizophrenia was performed on articles published between 1990 and May 2008.

RESULTS

Recent evidence indicates that schizophrenia increases predisposition towards metabolic dysfunction independent of environmental exposure. Both fasting and non-fasting triglycerides have emerged as important indicators of cardiometabolic risk, while metformin, thiazolidinediones and GLP-1 modulators may prove promising tools for managing insulin resistance.

CONCLUSION

Because of lifestyle, disease and medication effects, schizophrenia patients have significant risk for cardiometabolic disease. Routine monitoring, preferential use of metabolically neutral antipsychotics and lifestyle education are critical to minimizing risk, with a possible role for antidiabetic medications for management of insulin resistant states that do not respond to other treatment strategies.

Impact of lowering the criterion for impaired fasting glucose on identification of individuals with insulin resistance. The GISIR database

OBJECTIVE

We assessed the accuracy of the American Diabetes Association (ADA)2003 definition of impaired fasting glucose (IFG) in identifying subjects with low insulin sensitivity, and determined cardiovascular risk factors in ADA2003 IFG subjects.

RESEARCH DESIGN AND METHODS

This study included 930 non-diabetic Italian Caucasians from the GISIR database in which subjects underwent a hyperinsulinaemic-euglycaemic clamp performed with a standard technique. Low insulin sensitivity was defined as being in the lower quartile of glucose metabolized during the last hour of the clamp (M). Subjects were stratified in the following groups: normal fasting glucose (NFG) (<100 mg/dL), IFG100 (100-109 mg/dL), ADA1997 IFG110 (110-125 mg/dL), and ADA2003 IFG (100-125 mg/dL).

RESULTS

The sensitivity of identifying subjects with low insulin sensitivity increased adopting the ADA2003 criterion. After Bonferroni correction for multiple comparisons, both IFG100 and ADA1997 IFG110 showed significantly higher body mass index (BMI), waist, systolic blood pressure (SBP) and diastolic blood pressure (DBP), triglyceride, fasting plasma insulin (FPI) and fasting plasma glucose (FPG), and lower insulin sensitivity as compared with NFG. As compared with IFG100, ADA1997 IFG110 showed significantly higher BMI, waist, SBP, FPI, FPG, and lower insulin sensitivity. ADA2003 IFG group showed significantly higher BMI, waist, SBP and DBP, triglyceride, cholesterol, FPI, and FPG, but lower HDL levels and insulin sensitivity compared with NFG subjects.

CONCLUSIONS

Although neither the ADA2003 nor the ADA1997 definition of IFG appears to be particularly efficacious for the identification of subjects' low insulin sensitivity, lowering the criterion to the ADA2003 glucose threshold increased the sensitivity without affecting the specificity. ADA2003 IFG showed a worse cardiovascular risk profile compared with NFG.

Hydroxypropylmethylcellulose and methylcellulose consumption reduce postprandial insulinemia in overweight and obese men and women

Hydroxypropylmethylcellulose (HPMC) and methylcellulose (MC) are modified cellulose dietary fibers that generate viscous solutions in the gastrointestinal (GI) tract. This study assessed the effects of high viscosity (HV) HPMC, ultra-HV (UHV) HPMC, and medium viscosity MC on postprandial glucose and insulin responses in overweight and obese men and women (n = 50). After overnight fasts, subjects consumed 5 breakfast meals containing 75 g carbohydrate, each of which contained 1 of the following: 1 g HV-HPMC, 2 g HV-HPMC, 2 g UHV-HPMC, 4 g medium-viscosity MC or control (2 g cellulose). Test sequence was randomized and double-blind, except the MC test, which was last and single-blind (46 subjects completed all 5 tests). Glucose and insulin responses were determined pre-meal and for 120 min postprandially. Median (interquartile limits) peak glucose concentration was lower (P = 0.001) after the meal containing 2.0 g UHV-HPMC (7.1, 6.3-8.2 mmol/L) compared with the control meal (7.7, 6.6-8.7 mmol/L). The control did not differ from the other conditions for peak glucose or for any of the HPMC/MC conditions for glucose incremental areas under the curves (IAUC). Peak insulin was reduced (P < 0.05) for all HPMC/MC conditions compared with control. Insulin IAUC was lower than control (P < 0.001) after meals containing 2 g HV-HPMC, 2 g UHV-HPMC, and 4 g MC. GI symptoms did not differ among treatments. These findings indicate that HV-HPMC (1 and 2 g), UHV-HPMC (2 g), and MC (4 g) consumption reduced postprandial insulin excursions consistent with delayed glucose absorption.

Prevalence and incidence of the metabolic syndrome in the European Lacidipine Study on Atherosclerosis (ELSA) and its relation with carotid intima-media thickness

BACKGROUND

The European Lacidipine Study on Atherosclerosis (ELSA) randomized 2334 hypertensive patients to either the lipophilic calcium antagonist lacidipine or the beta-blocker atenolol for 4 years. About 35% of subjects in both groups received additional hydrochlorothiazide (12.5-25 mg/day). The patients were followed up for carotid intima-media thickness (IMT) changes for 3.7 years.

OBJECTIVES

The present post-hoc analyses were aimed at: describing the prevalence of the metabolic syndrome (MS) at baseline; investigating the effect of long-term antihypertensive therapy (and separately of atenolol and lacidipine) on MS prevalence; exploring whether MS at baseline influenced changes in carotid IMT and incidence of cardiovascular events during treatment; and describing the relations between MS and new cases of diabetes developing during treatment.

METHODS

At baseline 2034 patients had, in addition to blood pressure (BP), measurements of blood glucose, serum high-density lipoprotein (HDL)-cholesterol, triglycerides and body mass index (BMI > 28.8 for men and > 26.2 for women were taken to correspond to waist circumference > 102 and > 88 cm, respectively). These measurements were repeated after 4 years of treatment in 1444 patients. MS was defined according to Adults Treatment Panel III (ATP III).

RESULTS

A high proportion of ELSA patients (33.3%) had MS at baseline, with no difference between atenolol and lacidipine. Baseline IMT was slightly greater in MS patients, but only the difference in mean maximum IMT at common carotids and bifurcations (CBMmax) achieved significance (P = 0.0325). Progression of CBMmax was also slightly greater in MS patients (P = 0.0241), but significance was lost when adjusted for covariates. No significant difference was found in the incidence of new cardiovascular events between patients with and without MS. The incidence of new MS was 21.4%, and significantly greater in patients under atenolol (25.2%) than lacidipine (17.7%; P = 0.0045). New-onset diabetes occurred in 5.54% of ELSA patients, and was three times higher among patients with than those without MS (10.28 versus 3.43%, P > 0.0001).

CONCLUSIONS

Our analyses show a high prevalence of MS in ELSA hypertensives, a substantial incidence of new cases of MS and diabetes, the latter mostly among patients with MS. These analyses also show that in ELSA lacidipine was superior to atenolol, not only in showing a lower progression of carotid atherosclerosis, but also in causing a significantly lower incidence of new MS.

Productivity costs associated with cardiometabolic risk factor clusters in the United States

OBJECTIVE

Cardiometabolic risk factors such as overweight/obesity, hyperlipidemia, diabetes, and hypertension are prone to cluster together in the same individual and result in an elevated risk of cardiovascular disease and mortality. The purpose of this study was to examine and quantify the impact of cardiometabolic risk factor clusters independent of heart disease on productivity in a nationally representative sample of US adults.

METHODS

The current study estimated the impact of cardiometabolic risk factor clusters on missed work days and bed days, controlling for sociodemographic characteristics, comorbidity, and smoking status in a nationally representative, pooled 2000 and 2002 Medical Expenditure Panel Survey sample. Cardiometabolic risk factor clusters included BMI >or= 25 and two of the following three: diabetes, hyperlipidemia, and/or hypertension. All estimates were expressedin $US 2005. Sensitivity analyses were conducted to examine the impact of varying assumptions on the results.

RESULTS

After controlling for differences in sociodemographics, smoking and comorbidity, individuals with cardiometabolic risk factor clusters missed 179% more work days and spent 147% more days in bed (in addition to lost work days) than those without. Lost work days and bed days resulted in $17.3 billion annually in lost productivity attributable to cardiometabolic risk factor clusters in the United States. Sensitivity analyses resulted in a range of annual lost productivity costs from $3.2 to $23.1 billion.

CONCLUSIONS

Common cardiometabolic risk factor clusters have a significant deleterious impact on the US economy, resulting in $17.3 billion in lost productivity.

The metabolic syndrome in Australia: prevalence using four definitions

OBJECTIVE

To compare the prevalence of the Metabolic Syndrome (MetS) defined by four definitions and to determine which definition best identifies those at high cardiovascular disease (CVD) risk and with insulin resistance.

METHODS

AusDiab is a population-based survey of 11,247 Australians. Participants had anthropometry, blood pressure, and fasting biochemistry. Ten-year CVD risk was calculated.

RESULTS

The prevalence of the MetS using the ATPIII, WHO, IDF, and EGIR definitions was 22.1% (95%Cl: 18.8, 25.4), 21.7% (19.0, 24.3), 30.7% (27.1, 34.3), and 13.4% (11.8, 14.9), respectively. Comparing those with to those without the MetS, the odds ratios (95%CI) for having a 10 year CVD risk > or =15% were 6.6 (5.4, 8.2), 5.5 (4.7, 6.5), 5.6 (4.8, 6.6), and 3.5 (3.0, 4.1), for the WHO, ATPIII, IDF, and EGIR definitions, respectively. The population attributable risk (PAR) of high CVD risk due to the MetS was highest for the IDF (23.4%). Insulin resistance was detected in 56.1, 69.7, 50.9, and 91.1% of those meeting the ATPIII, WHO, IDF, and EGIR definitions, respectively.

CONCLUSION

The WHO definition was associated with the greatest CVD risk, but is not practical for clinical use. The higher PAR due to the IDF definition, with only slightly lower CVD risk than WHO, and clinical utility of the IDF definition, indicates that it may be a useful tool for CVD prevention.

Gamma glutamyl transferase and metabolic syndrome, cardiovascular disease, and mortality risk: the Framingham Heart Study

OBJECTIVE

To determine whether serum gamma-glutamyl transferase (GGT) predicts cardiovascular disease (CVD) morbidity and mortality, accounting for temporal changes in known CVD risk factors and C-reactive protein (CRP).

METHODS AND RESULTS

In 3451 Framingham Study participants (mean age 44 years, 52% women) we examined the relations of GGT with CVD risk factors, and prospectively determined the risk of new-onset metabolic syndrome, incident CVD, and death. GGT was positively associated with body mass index, blood pressure, LDL cholesterol, triglycerides, and blood glucose in cross-sectional analysis (P<0.005). On follow-up (mean 19 years), 968 participants developed metabolic syndrome, 535 developed incident CVD, and 362 died. The risk of metabolic syndrome increased with higher GGT (multivariable-adjusted hazard ratio [HR] per SD increment log-GGT, 1.26 [95%CI; 1.18 to 1.35]). Adjusting for established CVD risk factors (as time-dependent covariates updated quadriennially) and baseline CRP, a 1-SD increase in log-GGT conferred a 13% increase in CVD risk (P=0.007) and 26% increased risk of death (P<0.001). Individuals in the highest GGT quartile experienced a 67% increase in CVD incidence (multivariable-adjusted HR 1.67, 95%CI; 1.25 to 2.22).

CONCLUSIONS

An increase in serum GGT predicts onset of metabolic syndrome, incident CVD, and death suggesting that GGT is a marker of metabolic and cardiovascular risk.

Metabolic syndrome and early-onset coronary artery disease: is the whole greater than its parts?

OBJECTIVES

We sought to examine the association between the metabolic syndrome (MetS) (defined both by the 2001 National Cholesterol Educational Program Adult Treatment Panel III [ATP-III] definition and the American Heart Association/National Heart, Lung and Blood Institute [AHA/NHLBI] revision incorporating the lower threshold for impaired fasting glucose [IFG]) and early-onset coronary artery disease (CAD).

BACKGROUND

The impact of MetS on premature CAD has not been studied extensively. Lowering the threshold to define the IFG component (from 110 to 100 mg/dl) and the value of the syndrome as a whole versus its individual components are subjects of intense debate.

METHODS

We performed a case-control study with 393 early-onset CAD subjects (acute myocardial infarction, angina with > or =50% stenosis, or coronary revascularization) in men under age 46 years or women under age 56 years and 393 control subjects individually matched for gender, age, and race/ethnicity.

RESULTS

By conditional logistic regression, presence of ATP-III MetS without diabetes (adjusted odds ratio [adj-OR] 4.9; 95% confidence interval [CI] 3.4 to 8.0) and with diabetes (adj-OR 8.0, 95% CI 4.39 to 14.6) was a strong independent determinant of early-onset CAD. Using the AHA/NHLBI revision, these ORs became slightly stronger. However, neither definition of MetS remained significantly associated with early-onset CAD in multivariate models adjusting for individual components.

CONCLUSIONS

The presence of MetS imparts a high risk of early-onset clinical CAD, but the prognostic information associated with the syndrome is not greater than the sum of its parts.

Myocardial preconditioning against ischemia-reperfusion injury is abolished in Zucker obese rats with insulin resistance

Insulin resistance (IR) precedes the onset of Type 2 diabetes, but its impact on preconditioning against myocardial ischemia-reperfusion injury is unexplored. We examined the effects of diazoxide and ischemic preconditioning (IPC; 5-min ischemia and 5-min reperfusion) on ischemia (30 min)-reperfusion (240 min) injury in young IR Zucker obese (ZO) and lean (ZL) rats. ZO hearts developed larger infarcts than ZL hearts (infarct size: 57.3 +/- 3% in ZO vs. 39.2 +/- 3.2% in ZL; P < 0.05) and also failed to respond to cardioprotection by IPC or diazoxide (47.2 +/- 4.3% and 52.5 +/- 5.8%, respectively; P = not significant). In contrast, IPC and diazoxide treatment reduced the infarct size in ZL hearts (12.7 +/- 2% and 16.3 +/- 6.7%, respectively; P < 0.05). The mitochondrial ATP-activated potassium channel (K(ATP)) antagonist 5-hydroxydecanoic acid inhibited IPC and diazoxide-induced preconditioning in ZL hearts, whereas it had no effect on ZO hearts. Diazoxide elicited reduced depolarization of isolated mitochondria from ZO hearts compared with ZL (73 +/- 9% in ZL vs. 39 +/- 9% in ZO; P < 0.05). Diazoxide also failed to enhance superoxide generation in isolated mitochondria from ZO compared with ZL hearts. Electron micrographs of ZO hearts revealed a decreased number of mitochondria accompanied by swelling, disorganized cristae, and vacuolation. Immunoblots of mitochondrial protein showed a modest increase in manganese superoxide dismutase in ZO hearts. Thus obesity accompanied by IR is associated with the inability to precondition against ischemic cardiac injury, which is mediated by enhanced mitochondrial oxidative stress and impaired activation of mitochondrial K(ATP).