High plasma leptin levels are associated with impaired diastolic function in patients with coronary artery disease

BACKGROUND AND AIMS

Obese subjects have elevated leptin levels, which have been associated with increased risk of cardiovascular events. Because leptin has direct cellular effects on various tissues, we tested the hypothesis that leptin levels are associated with cardiac structure or function in patients with coronary artery disease (CAD).

METHODS AND RESULTS

The study population consisted of 1 601 CAD patients, of whom 42% had type 2 diabetes mellitus. Plasma leptin was measured in fasted state and an echocardiography performed. Leptin levels were not related to LV dimensions or LV ejection fraction (NS for all), but higher leptin levels were associated with elevated E/E' (9.43 vs. 11.94 in the lowest and the highest leptin quartile, respectively; p=0.018 for trend). Correspondingly, a decreasing trend was observed in E/A (1.15 vs. 1.06; p=0.037). These associations were independent of obesity and other relevant confounding variables.

CONCLUSION

We conclude that elevated plasma leptin levels are associated with impaired left ventricular diastolic function in patients with CAD independently of obesity and other confounding variables. Leptin may be one of the mechanistic links explaining the development of congestive heart failure in obese subjects.

Serum 25-hydroxyvitamin D is associated with major cardiovascular risk factors and cardiac structure and function in patients with coronary artery disease

BACKGROUND AND AIMS

Vitamin D deficiency has been associated with increased risk for cardiovascular (CV) disease, but the possible effects of Vitamin D on cardiac structure and function are not well characterized.

METHODS AND RESULTS

The correlation between 25-hydroxyvitamin D levels and metabolic and cardiac echocardiographic parameters was studied in ARTEMIS study population including 831diabetic and 659 non-diabetic patients with stable coronary artery disease (CAD). Low levels of Vitamin D were associated with high BMI (p < 0.001), high total and LDL cholesterol and triglyceride levels (p < 0.001 for all) in both diabetics and non-diabetics. Among non-diabetic patients, low Vitamin D was also associated independently with elevated systolic and diastolic blood pressure (p < 0.005). Low Vitamin D levels were independently associated with reduced left ventricular (LV) ejection fraction (p < 0.005) and increased left atrial diameter (p < 0.03) measured by cardiac ultrasound by 2-dimensional echo. In the non-diabetic group, low Vitamin D levels were associated with impaired LV filling (high E/E') (p < 0.03) and low E/A mitral flow pattern measured by Doppler echocardiography (p < 0.05). Among diabetics, low Vitamin D levels were also related to increased LV end-systolic diameter (p < 0.05) and right ventricular diameter (p < 0.005). The association between LV diastolic filling (E/E') and Vitamin D levels was significant (p < 0.01) after adjustment for the commonly recognized risk factors of diastolic dysfunction in linear regression analysis.

CONCLUSIONS

Low Vitamin D is associated with several major cardiovascular risk factors and cardiac structural changes including impaired systolic and diastolic function, which together may explain the association of low Vitamin D to worse cardiovascular outcome.

High plasma ghrelin protects from coronary heart disease and Leu72Leu polymorphism of ghrelin gene from cancer in healthy adults during the 19 years follow-up study

The aim of our investigation was to find out if ghrelin concentrations or polymorphisms predict the future risk for cardiovascular diseases and cancer in a population-based cohort initiated in 1991 (491 hypertensive and 513 control subjects). Total mortality and hospital events were followed up for 19 years. Fasting total ghrelin concentrations were determined and Arg51Gln, Leu72Met and -501 A > C polymorphisms identified. Cox regression analysis was performed. The mean value in the control cohort was 674 pg/ml whereas in the hypertensive cohort it was 661 pg/ml. The associations found suggest that in the controls the highest ghrelin quartile protected from CHD (coronary heart disease). The results were significant without or with adjustments for age, sex, smoking, systolic blood pressure and LDL cholesterol, BMI, type 2 diabetes or QUICK index. C/C variant of the promoter associated with the prevention of IHD (ischemic heart disease) in the hypertensive group (p<0.05). The controls with the Leu72Leu genotype had less cancer (p<0.05). In conclusion, high plasma ghrelin concentration was related to protection from CHD and Leu72Leu genotype to prevention of cancer in healthy adults during the 19 years follow-up. C/C promoter protects from IHD in the hypertensive subjects.

Serum ghrelin and the prediction of the development of impaired glucose regulation and Type 2 diabetes in middle-aged subjects

BACKGROUND

Ghrelin is a peptide hormone which has been shown to associate with obesity, hypertension and Type 2 diabetes (T2DM) in cross-sectional studies.

AIM

To study whether total ghrelin levels have predictive value for the incidence of impaired glucose regulation (IGR) or T2DM.

SUBJECTS AND METHODS

The subjects of this prospective follow-up study (no.=201) belonged to a population-based cohort collected in Northern Finland. Oral glucose tolerance tests (OGTT) and measurements of fasting serum total ghrelin, lipids, blood pressure and body mass index were performed at the beginning and at the end of the study. The mean follow-up time was 5.1 yr. The subjects had normal glucose tolerance (NGT) at the beginning of the study.

RESULTS

T2DM developed in 6 (3%), impaired fasting glucose (IFG) in 6 (3%) and impaired glucose tolerance (IGT) in 35 (17.4%) subjects. The baseline ghrelin concentrations did not differ between the two studied groups: median fasting serum total ghrelin concentration was 733 pg/ml (25th-75th percentiles: 571-961 pg/ml) among those who maintained NGT, and 661 pg/ml (25th-75th percentiles: 527- 878 pg/ml) among those who developed IGR (IFG and/or IGT) or T2DM (p=0.421). The baseline ghrelin concentrations did not explain the changes in the 0-h or 2-h blood glucose concentrations in regression models.

CONCLUSIONS

Our findings suggest that fasting serum total ghrelin levels measured at one time point might not have predictive value for the development of abnormalities in glucose tolerance.

Gastric bypass and glucose metabolism

Roux-en-Y gastric bypass leads to a marked improvement of glucose control. The mechanisms are only partly known. Gastrointestinal hormones may play a role. Of these, glucagon-like peptide 1 and peptide YY have been most consistently associated with the beneficial effects of gastric bypass on glucose metabolism and weight. In this paper, a short review of the topic is presented and a suggestion of the improvement of glucose metabolism is made based on the current published work.

Plasma adiponectin concentration is associated with ambulatory daytime systolic blood pressure but not with the dipping status

The objective of this study was to analyse the relationship between the ambulatory blood pressure (ABP) measurement and plasma adiponectin levels in a population-based cohort. Non-hypertensive, non-diabetics from the Oulu Project Elucidating Risk of Atherosclerosis cohort aged 40-60 years with ABP measurement available in 226 men and 236 women were analysed. ABP was recorded using the fully automatic SpaceLabs 90207 oscillometric unit. Plasma adiponectin concentrations were assayed using the enzyme-linked immunosorbent assay method. Without adjustment the highest plasma adiponectin tertile was associated with the lowest ABP and office BP measurements (P from 0.025 to P<0.001, respectively). Only the association of plasma adiponectin concentration with systolic ABP was independent of other conventional risk factors (age, body mass index (BMI), waist, gender, insulin sensitivity index, smoking and alcohol consumption) for hypertension (P=0.017). No association was observed between systolic dipping pattern and adiponectin level. The plasma high adiponectin concentration is independently associated with low daytime systolic ABP value. The mechanisms may include effects on endothelial function and the sympathetic nervous system.

Leptin and lipid metabolism in chronic kidney failure

OBJECTIVE

In the general population, leptin has been associated with atherosclerosis and has been shown to interfere with lipoprotein profiles. Patients with chronic renal failure are at increased risk of cardiovascular disease and display alterations in both lipoprotein and leptin levels. The aim of this study was to investigate the relationship between leptin and the lipoprotein profile in non-dialyzed patients with chronic kidney disease (CKD).

MATERIAL AND METHODS

Leptin and lipid and lipoprotein concentrations were studied in 73 CKD patients and in 68 healthy controls in a cross-sectional case-control design.

RESULTS

The mean leptin levels were increased in the CKD patients (24.0 (SD 37.1) ng/mL) compared to those in controls (9.0 (SD 8.5) ng/mL) (p = 0.008). Also, the ratio between leptin levels and body mass index (leptin/BMI) was increased in CKD patients (mean 0.80 (SD 1.03)) compared to that in controls (0.31 (SD 0.24)) (p = 0.001). In linear regression analysis, leptin independently predicted total cholesterol and triglycerides in CKD patients (p = 0.010 and p = 0.001, respectively) and ratio between total and HDL cholesterol (Chol/HDL) in controls (p = 0.024). Furthermore, in CKD patients, the leptin/BMI predicted the variation in total cholesterol and triglycerides (p = 0.010 and p = 0.002, respectively).

CONCLUSIONS

Leptin concentrations and leptin/BMI were elevated in CKD patients compared to those in controls. Leptin levels in both study groups, and leptin/BMI in the CKD group, were associated with atherogenic lipid profiles, which may contribute to the elevated cardiovascular risk that has been linked to hyperleptinaemia.

Early atherosclerosis and IgG2 to bacteria are associated with FcgammaRIIa genotype in non-smokers

BACKGROUND

Involvement of low density lipoprotein (LDL) immune complexes (ICs) in atherogenesis has been proposed. Human FcgammaRIIa receptor (CD32) plays a crucial role in the phagocytosis of IgG(2) ICs and a functional point mutation 131His/Arg diminishes IgG(2) binding to the receptor.

STUDY DESIGN

We examined FcgammaRIIa-131His/Arg polymorphism, IgG(2) antibody titres to oxidized low-density lipoprotein (OxLDL) and Streptococcus pneumoniae cell wall polysaccharide (CWPS) and subclinical atherosclerosis in a large cohort of Finnish subjects (n = 1041).

RESULTS

Non-smoking subjects with homozygous 131His/His genotype had more premature atherosclerosis (P = 0.004) and higher IgG(2) to bacterial CWPS (P = 0.002) compared with other genotypes. Smoking subjects had significantly higher intima-media thickness (IMT) than that of non-smokers (P < 0.001) and genotype-dependent associations were indistinct. There was no association between FcgammaRIIa genotype and antibody titres to OxLDL.

CONCLUSIONS

Our data demonstrate that FcgammaRIIa 131His/Arg polymorphism is associated with subclinical atherosclerosis in non-smoking subjects. Furthermore, FcgammaRIIa genotype is associated with IgG(2) titres to bacterial CWPS, but not to OxLDL. These data propose possible involvement of FcgammaRIIa receptor in atherogenesis.

ApoE phenotype is associated with inflammatory markers in middle-aged subjects

OBJECTIVES

Apolipoprotein (apo) E phenotype has been associated with inflammation markers. The determinants of these associations and the relationship between novel inflammation marker, resistin, and apoE phenotype are studied here.

METHODS AND RESULTS

Middle-aged subjects of the population- based cohort (n = 526) of the OPERA- study were studied. Intima-media thickness (IMT) was measured with carotid ultrasound. The results suggest that, apoE phenotype was a significant independent predictive factor for resistin (p < 0.01) and hsCRP (p < 0.01) levels. The association of ApoE phenotype with hsCRP was seen among the subjects with the normal renal function (p = 0.005). ApoE4 was associated (p < 0.01) with the lowest hsCRP in the lowest IMT quartile while it's relation with the highest resistin levels was evident in the highest IMT quartile.

CONCLUSIONS

ApoE phenotype is an independent determinant of plasma resistin and hsCRP levels. The extent of atherosclerosis and renal function seem to modify the effects of apoE phenotype on inflammatory parameters.

The effect of a short-term hypocaloric diet on liver gene expression and metabolic risk factors in obese women

BACKGROUND AND AIMS

Most gene expression studies examining the effect of obesity and weight loss have been performed using adipose tissue. However, the liver also plays a central role in maintaining energy balance. We wanted to study the effects of a hypocaloric diet on overall hepatic gene expression and metabolic risk factors.

METHODS AND RESULTS

The study subjects were middle-aged, obese women. The diet intervention subjects (n=12) were on a hypocaloric, low-fat diet for 8 weeks with a daily energy intake of 5.0 MJ (1200 kcal), while the control subjects (n=19) maintained their weight. Liver biopsies were taken at the end of the diet period during a gallbladder operation. Hepatic gene expression was analyzed using microarrays by comparing the gene expression profiles from four subjects per group. A global decrease in gene expression was observed with 142 down-regulated genes and only one up-regulated gene in the diet intervention group. The diet resulted in a mean weight loss of 5% of body weight. Triglyceride and fasting insulin concentrations decreased significantly after the diet.

CONCLUSIONS

The global decrease in hepatic gene expression was unexpected but the results are interesting, since they included several genes not previously linked to weight reduction. However, since the comparison was made only after the weight reduction, other factors in addition to weight loss may also have been involved in the differences in gene expression between the groups. The decrease in triglyceride and fasting plasma insulin concentrations is in accordance with results from previous weight-loss studies.

Adiponectin concentration and insulin indicators following overfeeding in identical twins

Low adiponectin levels have been associated with high body mass index, low insulin sensitivity, and diabetes.

OBJECTIVE

To assess the relationships between changes in serum adiponectin concentration and adiposity, glucose, and insulin in response to long-term overfeeding in identical twins and to calculate the twin resemblance in serum adiponectin concentrations.

SUBJECTS AND DESIGN

Twenty-four sedentary young men [mean (+/-SD) age, 21+/-2 yr] who constituted 12 pairs of healthy identical twins were studied for metabolic and adiponectin changes in response to overfeeding.

INTERVENTION

Subjects were overfed by 84,000 kcal over a 100-day period.

OUTCOME MEASURES

The overfeeding study provides an opportunity to examine the relationships between adiponectin and changes in body weight, adiposity, plasma glucose and insulin.

RESULTS

Serum adiponectin concentration correlated positively with body weight (r= 0.41, p=0.05) at baseline but not with indicators of adiposity or with visceral fat. No relationship existed between baseline adiponectin concentration and body weight or adiposity gains with overfeeding. However, serum adiponectin decreased significantly by -2.35+/-0.48 microg/ml (p=0.001) in response to overfeeding. Baseline adiponectin levels correlated negatively with changes in plasma fasting glucose levels (r=-0.53, p=0.01) and homeostasis model assessment index (r=-0.41, p=0.05), independently of fat mass. The intrapair coefficient for twin resemblance (r=0.75, p=0.001) strongly suggests that baseline serum adiponectin concentration is a familial trait.

CONCLUSIONS

These data provide evidence that adiponectin concentration is a familial trait in normal-weight individuals, that it decreases when challenged by positive energy balance, and that its overfeeding-induced variations are correlated with glucose and insulin levels.

Rosiglitazone treatment increases plasma levels of adiponectin and decreases levels of resistin in overweight women with PCOS: a randomized placebo-controlled study

OBJECTIVE

Abdominal obesity, insulin resistance and compensatory hyperinsulinaemia play a central role in the pathogenesis of the polycystic ovary syndrome (PCOS). Abdominal adipose tissue is a source of adipokines, such as adiponectin and resistin, both of which may be involved in the development of insulin resistance and chronic inflammation in PCOS. Ghrelin, an important regulatory peptide of food intake, may also play a role in metabolic disturbances related to PCOS. The aim of this study was to examine the effects of 4 months of treatment with the insulin sensitizer rosiglitazone on plasma adiponectin, resistin and ghrelin levels in overweight women with PCOS.

DESIGN

A randomised placebo-controlled study.

METHODS

Thirty overweight/obese women with PCOS (body mass index>25 kg/m(2), mean age 29.1+/- 1.2 (S.E.M.) years) were randomly allocated to either rosiglitazone (Avandia, 4 mg twice a day) or placebo treatment. Plasma levels of adiponectin, resistin and ghrelin and their correlation to serum levels of insulin, C-peptide and steroid hormones, and insulin sensitivity (euglycaemic hyperinsulinaemic clamp) were assessed.

RESULTS

Adiponectin and ghrelin levels correlated significantly with most metabolic markers of insulin resistance and with serum levels of DHEA and 17-hydroxyprogesterone. Plasma levels of adiponectin increased from 9.26+/-0.90 (S.E.M.) to 22.22+/-3.66 microg/ml (P<0.001) and those of resistin decreased from 12.57+/-1.63 to 9.21+/-0.53 ng/ml (P=0.009) at 4 months of treatment, but plasma ghrelin levels did not change.

CONCLUSIONS

Rosiglitazone had beneficial effects on serum levels of adiponectin and resistin, suggesting that these adipocytokines may contribute to the improvement in insulin sensitivity observed during the treatment.