Interrelationship Between Insulin Resistance and Menopause on the Metabolic Syndrome and Its Individual Component Among Nondiabetic Women in the Kinmen Study

Genome-wide association study identifies novel recessive genetic variants for high TGs in an Arab population

Abnormal blood lipid levels are influenced by genetic and lifestyle/dietary factors. Although many genetic variants associated with blood lipid traits have been identified in Europeans, similar data in Middle Eastern populations are limited. We performed a genome-wide association study with Arab individuals (discovery cohort: 1,353; replication cohort: 1,176) from Kuwait to identify possible associations of genetic variants with high lipid levels. We used Illumina HumanOmniExpress BeadChip and candidate SNP genotyping in the discovery and replication phases, respectively. For association tests, we used genetic models that were based on additive and recessive modes of inheritance. High triglycerides (TGs) were recessively associated with six risk variants (rs1002487/RPS6KA1, rs11805972/LAD1) rs7761746/Or5v1, rs39745/CTTNBP2-LSM8, rs2934952/PGAP3, and rs9626773/RP11-191L9.4-CERK) at genome-wide significance (P  6.12E-09), and another six variants (rs10873925/ST6GALNAC5, rs4663379/SPP2-ARL4C, rs10033119/NPY1R, rs17709449/LINC00911-FLRT2, rs11654954/CDK12-NEUROD2, and rs9972882/STARD3) were associated at borderline significance (P  5.0E-08). High TG was also additively associated with rs11654954. All of the 12 identified markers are novel and are harbored in runs of homozygosity. Literature evidence supports the involvement of these gene loci in lipid-related processes. This study in an Arab population augments international efforts to identify genetic regulation of lipid traits.

Effect of the particle size of cellulose from sweet potato residues on lipid metabolism and cecal conditions in ovariectomized rats

This study aims to examine the effect of the particle size of cellulose from sweet potato residues on lipid metabolism and cecal conditions in ovariectomized rats. Forty mature female Wistar rats were divided into five groups. The sham-operated group was used as the sham control. The other four groups were double-ovariectomized and assigned to the model, ordinary cellulose (100 g kg(-1) diet), microcrystalline cellulose (100 g kg(-1) diet), and cellulose nanocrystal (100 g kg(-1) diet) groups. As the cellulose particle size decreased, the body weight gain and food intake were decreased. The plasma lipids and hepatic lipids were decreased. In addition, the mRNA levels of cholesterol 7α-hydroxylase, farnesoid X receptor, and 3-hydroxy-3-methylglutaryl coenzyme A reductase were decreased, whereas those of ileal apical sodium-dependent bile acid transporter and intestinal bile acid binding protein were increased. The cecum weight, cecum content, and short-chain fatty acid concentration and the amount of total bile acids in the small intestinal content, as well as the bile acids and neutral steroids in fecal excretion, were increased. These results indicate that as the particle size decreased, cellulose was more effective in preventing ovarian hormone deficiency-induced hyperlipidemia and in improving intestinal health.

Associations of insulin resistance with cardiovascular risk factors and inflammatory cytokines in normal-weight Hispanic women

OBJECTIVE

To investigate the associations of markers of insulin resistance with cardiovascular disease risk factors and inflammation in young, normal-weight, Hispanic women.

RESEARCH DESIGN AND METHODS

Seventy-one normal-weight (BMI <25 kg/m(2)) Hispanic women (age, 20-39 years) participated in a fasting blood draw for glucose, insulin, lipids, and inflammatory markers; a glucose tolerance test; anthropometric and blood pressure measurements; body composition by dual-energy x-ray absorptiometry; and measurements of cardiorespiratory fitness via Vo2max and daily physical activity by accelerometer. RESULTS Six percent of participants had impaired fasting glucose, 14% had impaired glucose tolerance, and 48% had at least one cardiovascular disease risk factor. Homeostasis model assessment of insulin resistance (HOMA-IR) and fasting insulin were positively correlated with glucose, triglycerides, systolic blood pressure, and diastolic blood pressure, and were negatively correlated with adiponectin (P < 0.05). The 2-h insulin was positively correlated with diastolic blood pressure, triglycerides, and high-sensitivity C-reactive protein. HOMA-IR and fasting insulin remained significantly and positively related to glucose, triglycerides, and blood pressure after adjustment for body composition. The relationships between markers of insulin resistance and adiponectin and high-sensitivity C-reactive protein were attenuated after adjustment for body composition.

CONCLUSIONS

Surrogate markers of insulin resistance were associated with cardiovascular disease risk factors and inflammation in young, normal-weight, Hispanic women. Our findings suggest that HOMA-IR, fasting, and 2-h insulin may be important clinical markers for identifying young, normal-weight, Hispanic women who may be at risk for development of type 2 diabetes and cardiovascular disease. Our findings show the importance of early screening for prevention of type 2 diabetes and cardiovascular disease in this population.

Daidzein improves insulin resistance in ovariectomized rats

OBJECTIVE

To determine whether daidzein improves insulin resistance by modifying weight gain, visceral fat accumulation, blood lipids and serum cytokines levels in ovariectomized Sprague-Dawley rats.

MATERIALS AND METHODS

Twenty-eight 12-week-old female rats were divided into three groups: the sham-operated group (SHAM) (n =10), the ovariectomized group receiving daidzein therapy (DAID) (n =10), and the ovariectomized control group (Control) (n =8). The rats in the DAID group received 50 mg/kg daidzein via gavage daily. Weight and food intake were recorded every 2 weeks. All of the animals were euthanized 12 weeks after ovariectomy, after which their fasting insulin, glucose, blood lipids, estradiol, interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), adiponectin and leptin levels were measured.

RESULTS

After 12 weeks, the ovariectomized rats demonstrated an increase in their body weight and visceral fat; compared to the SHAM rats, the ovariectomized rats also experienced a significant increase in their serum IL-6 levels and insulin resistance, which was calculated using the homeostatic model assessment of insulin resistance (HOMA-IR) (p <0.05). Daidzein therapy decreased weight gain, visceral fat, the HOMA-IR index and IL-6 levels that were induced by ovariectomy. Rats which had received daidzein therapy had lower levels of TNF-α, leptin and blood lipids (except for high density lipoprotein cholesterol) than the other two groups. IL-6 levels positively correlated with the HOMA-IR index in all of the rats after adjustment for body weight (r =0.495; p =0.016).

CONCLUSION

We conclude that daidzein can improve insulin resistance induced by ovariectomy by decreasing weight gain, visceral fat accumulation, blood lipids, TNF-α, leptin and IL-6 levels.

Menopause is an independent predictor of metabolic syndrome in Iranian women

BACKGROUND

Gender differences in prevalence and consequences of the metabolic syndrome as a strong predictor of cardiovascular disease (CVD), are challenging problems. Postmenopausal status may explain in part the cause of acceleration of CVD with aging. The purpose of this study was to investigate the relation of menopause and metabolic syndrome independent of aging among Iranian women.

METHODS

On the basis of consecutive recruitment, 940 women between 20 and 76 years old participated in the study. Anthropometric indices, fasting blood glucose, lipid profile were measured, Framingham risk score and homeostasis model assessment (HOMA-IR) were calculated for all participants. The metabolic syndrome (MetS) was defined according to the National Cholesterol Education Program Adult Treatment Panel III. We used IDF definition for metabolic syndrome modified by our recent local data as an alternative measurements.

RESULTS

The overall prevalence of metabolic syndrome was 26.4%. Its prevalence was 53.5% in postmenopausal versus 18.3% in premenopausal women. On binary logistic regression analysis, HOMA index, body mass index, waist to hip ratio, family history of diabetes and hypertension had an independent and significant effect on metabolic syndrome. Age-adjusted odds ratio (OR) of postmenopausal status for metabolic syndrome was 2.85 (95%CI: 1.31-6.20) (P<0.008). Framingham risk score was 8.3+/-7.7 in MetS+ve cases versus 1.9+/-2.1 in MetS-ve cases (P<0.001). There were significant differences between Framingham risk score in postmenopause 9.1+/-6.4 versus premenopause 1.6+/-1.6 (P<0.001). A significant correlation was found between Framingham risk score and body mass index, waist to hip ratio, HOMA-IR and components of metabolic syndrome (P<0.001). Forty percent of participants with premature menopause had metabolic syndrome versus 24% in age-matched group and Framingham risk score was significantly higher than normal cases 5.4+/-4.9 versus 2.0+/-2.3 (P<0.001).

CONCLUSION

Menopausal status can be a predictor of metabolic syndrome independent of age in Iranian women. Menopause is a process closely related to insulin resistance and cardiovascular risk factors.

Weight change and incident metabolic syndrome in Iranian men and women; a 3 year follow-up study

Background

Although the association of weight gain and developing metabolic syndrome (MetS) has been reported in the Western and Asian populations, data on the gender-stratified effects of weight change (including weight loss) on incident MetS and its components in the Middle East Caucasians is still scarce.

Methods

A total of 1431 men and 2036 women aged ≥ 20 years with BMI > 18.5 kg/m² were followed over 3 years. Multivariate logistic regression analysis was used to estimate the relative risk (RR) of MetS and its components (the Adult Treatment Panel III definition) associated with gender-stratified quintiles of percent weight change. Subjects with MetS at baseline were excluded for analyzing the RR of MetS.

Results

There was 20.4% (95% CI, 19.6–21.2) age-adjusted incident MetS (18.4% male vs. 23.1% women). In men, mild weight gain (WG) predicted high waist circumference (WC) and high triglyceride; moderate WG predicted MetS (RR 2.5, 95% CI 1.4–4.3), high WC and high blood pressure (BP); large WG predicted MetS (RR 3.2, 95% CI 1.8–5.7) and its components, except for high fasting plasma glucose. In women, mild WG predicted MetS (RR 2.5, 95% CI 1.4–4.3), high WC and high BP; moderate WG predicted Mets (RR 4.6, 95% CI 2.7–8.0), high WC and high triglyceride; large WG predicted MetS (RR 6.6, 95% CI 3.8–11.3) and its components except for low HDL-cholesterol. Mild weight loss had protective effect on high WC in both genders and MetS in men (RR 0.5, 95% CI 0.26–0.97, P = 0.04).

Conclusion

Weight change showed different effects on MetS in men and women. In women, mild WG predicted MetS; however, mild weight loss was protective against MetS in men and high WC in both genders.

The effect of menopause on carotid artery remodeling, insulin sensitivity, and plasma adiponectin in healthy women

BACKGROUND

The mechanisms by which menopause may influence the systemic subclinical atherosclerosis are unexplained. The aim of this cross-sectional study was to evaluate the associations between early menopause, established cardiovascular (c-v) risk factors, metabolic parameters (insulin secretion and sensitivity, plasma adiponectin), and carotid intima-media thickness (IMT) in healthy women.

METHODS

In 74 menopausal women (mean age = 51 +/- 3 years, mean duration of menopause = 2.9 +/- 1.2 years) and in 74 nonmenopausal women comparable for age and body mass index (BMI), common carotid artery (CCA) luminal diameter, and IMT in different carotid segments were measured in digitized ultrasound images. Insulin sensitivity and secretion were assessed using the euglycemic hyperinsulinemic clamp technique and oral glucose tolerance test (OGTT). Insulin secretion was reconstructed by mathematical modeling.

RESULTS

CCA diameter (5.55 +/- 0.46 vs. 5.21+/- 0.51 mm, P < 0.001), CCA IMT (608 +/- 78 vs. 576 +/- 74 microm, P < 0.01) and systolic blood pressure (BP) (117 +/- 12 vs. 113 +/- 11 mm Hg, P < 0.05) were higher in menopausal women, whereas CCA IMT/diameter ratio and IMT in other carotid segments did not differ between the groups. By multivariate models, independent predictors of CCA diameter were menopause and body weight (cumulative R2 = 0.37) and independent correlates of CCA IMT were luminal diameter, systolic BP and low-density lipoprotein (LDL) cholesterol (cumulative R2 = 0.48). Fasting insulin, insulin secretion, and sensitivity and plasma adiponectin were similar in the two groups and were not related to carotid IMT.

CONCLUSIONS

Early menopause is associated with CCA remodeling, characterized by a proportional increase in luminal diameter and wall thickness, independent of atherosclerotic risk factors and metabolic variables.

Metabolic syndrome: prevalence, associated factors, and C-reactive protein: the MADRIC (MADrid RIesgo Cardiovascular) Study

The metabolic syndrome (MS) is defined by the clustering of a number of cardiovascular risk factors. The aims of the present study were to estimate the prevalence of MS in Madrid (Spain) by 2 definitions and to investigate its relationship with several sociodemographic factors and C-reactive protein (CRP) levels. This was a cross-sectional population study, and participants were 1344 subjects aged 31 to 70 years. Clinical evaluation included data on sociodemographic and cardiovascular background, physical examination, fasting glucose, triglycerides, and high-density lipoprotein cholesterol. The CRP levels were determined in a subgroup of 843 subjects. The diagnosis of MS was made according to the 2005 Adult Treatment Panel III (ATP III) and International Diabetes Federation (IDF) definitions. The age- and sex-adjusted prevalence of MS was 24.6% (95% confidence interval [CI], 22.3%-26.9%) using the ATP III definition and 30.9% (95% CI, 28.4%-33.3%) using the International Diabetes Federation definition. The overall agreement rate was 91.5% (kappa = 0.80; 95% CI, 0.76-0.83). Prevalence figures by both definitions were higher in men than in women and increased with age. Male sex, older age, low educational level, and physical inactivity were all determinants of ATP III-defined MS. The presence of MS or any of its components was associated with high CRP levels. In a logistic regression analysis, low educational level and waist circumference were the best predictors for high CRP level. The prevalence of MS in the Madrid region is one of the highest in Europe and confirms the strong Spanish regional variability in this syndrome frequency. Some sociodemographic and lifestyle factors, particularly educational level, are predictors for MS and high CRP levels.

Time course of liver lipid infiltration in ovariectomized rats: impact of a high-fat diet

OBJECTIVES

The present study was undertaken to determine the time course of liver lipid infiltration in ovariectomized (Ovx) rats and the impact of high-fat (HF; 42% kJ) feeding on this response.

METHODS

In a first step, Ovx rats were compared to Sham-operated (Sham) and Ovx rats supplemented with 17beta-estradiol (OvxE2) to evaluate the effect of estrogen removal. In a second time, Ovx rats fed a HF diet (OvxHf) were compared with normally fed Ovx rats. Animals were killed after 3, 8, and 13 weeks of their respective treatment (n=8 rats/group). We measured liver triacylglycerol (TAG) content, fat pad mass, and several other plasma parameters.

RESULTS

Ovariectomy resulted in the typical increase in energy intake and body weight. Liver TAG accumulation was 35, 43, and 99% higher in Ovx than in Sham rats after 3, 8, and 13 weeks, respectively. The ovariectomy-induced liver lipid infiltration was completely prevented by estrogen replacement. On the opposite, plasma TAG concentrations were lower in Ovx than in Sham and OvxE2 rats. HF feeding in Ovx rats resulted in a significant (P<0.05; 38 versus 22 mg/g at 13-week) accumulation of fat in liver as compared to normally fed Ovx rats.

CONCLUSIONS

Ovariectomy results in a progressive accumulation of fat in liver over a 13-week period. In addition, HF feeding in Ovx rats lead to an even more severe liver lipid infiltration. These data indicate that the absence of estrogens in rat favours fat accretion in liver, which is highly amplified by a HF diet.