Proteomics and lipids of lipoproteins isolated at low salt concentrations in D2O/sucrose or in KBr

There is much interest in the significance of apolipoproteins and proteins that are noncovalently associated with lipoproteins. It is possible that the high ionic strength used for isolation of lipoproteins with KBr and NaI could alter the pattern of associated exchangeable proteins. Here we describe lipoprotein classes fractionation from up to 0.5 ml of serum or plasma with buffers of physiological ionic strength and pH prepared with deuterium oxide (D(2)O) and sucrose. An advantage of the D(2)O/sucrose procedure was that the lipoproteins could be directly analyzed by the techniques described without need for desalting. We compared the isolated lipoproteins with those obtained using ultracentrifugation in KBr from the same plasma pool. Electrophoretic homogeneity of the lipoproteins was very similar using the two methods, as well as their lipid composition evaluated by HPLC. Two-dimensional electrophoresis and surface-enhanced laser adsorption/ionization time-of-flight mass spectrometry indicated that the patterns of exchangeable proteins of VLDL isolated using with the two procedures were very similar. However, significant differences were found in the profiles of LDL and HDL, indicating that the D(2)O/sucrose method allowed a more complete characterization of its exchangeable apolipoproteins and proteins.

Life style habits such as alcohol consumption and physical activity in relation to serum apoB / apoA-I ratio amongst 64-year-old women with varying degrees of glucose tolerance

OBJECTIVES

To investigate how life style factors such as alcohol consumption and physical activity relate to the serum apoB / apoA-I ratio in a cohort of middle-aged women with varying degrees of glucose tolerance.

DESIGN

Observational, cross-sectional cohort study.

SETTING

Research laboratory at a University Hospital.

SUBJECTS

A screened cohort of 64-year-old postmenopausal women with varying degrees of glucose tolerance, ranging from diabetes (n = 232), impaired (n = 212) and normal (n = 191) glucose tolerance.

MAIN OUTCOME MEASURE

ApoB / apoA-I ratio in relation to alcohol consumption and physical activity as assessed by questionnaires.

RESULTS

Alcohol consumption and regular physical activity at high levels were inversely associated with the serum apoB / apoA-I ratio independently of confounding factors such as obesity, lipid-lowering treatment, degree of glucose tolerance and hormone replacement therapy. Alcohol seemed related to the apoB / apoA-I ratio mainly through increasing apoA-I, whereas physical activity seemed mainly related to lowering of apoB. Alcohol consumption above a daily intake of 8.9 g, i.e. less than a glass of wine was accompanied by a decrease in apoB / apoA-I ratio.

CONCLUSIONS

Amongst these 64-year-old women with varying degrees of glucose tolerance, a moderate alcohol intake and regular physical exercise leading to sweating were associated with lower apoB / apoA-I ratio and these effects seem to be additive.

Low Serum Testosterone and High Serum Estradiol Associate With Lower Extremity Peripheral Arterial Disease in Elderly Men

OBJECTIVES

This study sought to determine whether serum levels of testosterone and estradiol associate with lower extremity peripheral arterial disease (PAD) in a large population-based cohort of elderly men.

BACKGROUND

Few studies have explored the relationship between serum sex steroids and lower extremity PAD in men.

METHODS

The Swedish arm of the MrOS (Osteoporotic Fractures in Men) study (n = 3,014; average age 75.4 years) assessed ankle-brachial index (ABI) and defined lower extremity PAD as ABI <0.90. Radioimmunoassay measured serum levels of total testosterone, estradiol, and sex hormone-binding globulin, and we calculated free testosterone and free estradiol levels from the mass action equations.

RESULTS

A linear regression model including age, current smoking, previous smoking, diabetes, hypertension, body mass index, free testosterone, and free estradiol showed that free testosterone independently and positively associates with ABI (p < 0.001), whereas free estradiol independently and negatively associates with ABI (p < 0.001). Logistic regression analyses showed that free testosterone in the lowest quartile (vs. quartiles 2 to 4; odds ratio [OR] 1.65, 95% confidence interval [CI] 1.22 to 2.23, p = 0.001) and free estradiol in the highest quartile (vs. quartiles 1 to 3; OR 1.45, 95% CI 1.09 to 1.94, p = 0.012) independently associate with lower extremity PAD.

CONCLUSIONS

This cross-sectional study shows for the first time that low serum testosterone and high serum estradiol levels associate with lower extremity PAD in elderly men. Future prospective and interventional studies are needed to establish possible causal relationships between sex steroids and the development of lower extremity PAD in men.

Dissociation between adipose tissue expression and serum levels of adiponectin during and after diet-induced weight loss in obese subjects with and without the metabolic syndrome

The study aimed to examine if dysmetabolic subjects (MetS+) have lower adiponectin gene expression and lower circulating adiponectin levels than non-dysmetabolic obese subjects (MetS-) at baseline, if adiponectin expression and adiponectin concentration rise more in the dysmetabolic group during weight loss, and if v-SNARE Vti1a (vesicle transport soluble NSF attachment protein receptor vps10p tail interacting 1a) expression increases during the weight loss, as a mechanism for increased adiponectin secretion. Twenty-one obese MetS+ and 19 obese MetS- subjects underwent a very low-energy diet for 16 weeks followed by 2 weeks of refeeding. Abdominal subcutaneous adipose tissue biopsies and blood samples were taken before, during, and after dieting for DNA microarray, reverse transcriptase-polymerase chain reaction, and biochemical analyses. Serum adiponectin was also assessed in a sex- and age-matched healthy, nonobese reference group. Weight decreased by 26.3+/-9.8 kg in the MetS+ group and 28.2+/-8.4 kg in the MetS- group with concomitant reductions in insulin, hemoglobin A1c, and triglycerides that were more pronounced in the MetS+ group. Initially, the MetS+ subjects had lower serum adiponectin, but the differences disappeared at week 8, with a continuous increase in serum adiponectin throughout the study in both groups to a level that was higher than in the reference group. The expression of adiponectin and v-SNARE Vti1a did not differ between the groups or over time. In conclusion, obese subjects with the metabolic syndrome had lower circulating adiponectin than subjects without the syndrome. Weight loss increased serum levels of adiponectin without a parallel increase in adiponectin gene expression. The mechanisms involved in the regulation of adiponectin levels merits further investigation.

Tesaglitazar, a dual peroxisome proliferator-activated receptor alpha/gamma agonist, improves apolipoprotein levels in non-diabetic subjects with insulin resistance

AIM

To determine the effects of the peroxisome proliferator-activated receptor (PPAR) alpha/gamma agonist tesaglitazar on serum levels of apolipoprotein (apo) A-I, apoB, and apoCIII in non-diabetic insulin-resistant subjects.

METHODS

This randomized, double-blind, multicentre, placebo-controlled trial examined the effect of tesaglitazar (0.1, 0.25, 0.5, and 1mg) once daily for 12 weeks on apolipoprotein levels in 390 abdominally obese subjects with hypertriglyceridaemia.

RESULTS

Tesaglitazar dose-dependently increased serum concentrations of apoA-I (p<0.009) and decreased concentrations of apoB (p<0.0001), the apoB/apoA-I ratio (p<0.0001), and apoCIII (p<0.0001). Similar improvements were observed in all subgroups of subjects, where individuals were grouped according to age, gender, baseline body mass index, serum triglycerides and high-density lipoprotein cholesterol levels. Low-density lipoprotein particle concentrations were also dose-dependently reduced by tesaglitazar (p<0.0001).

CONCLUSION

Although tesaglitazar is no longer in clinical development, these data indicate that dual PPARalpha/gamma agonism may be a useful pharmacological approach to improve the atherogenic dyslipidaemia associated with insulin resistance.

Relationships between free radical levels during carotid endarterectomy and markers of arteriosclerotic disease

BACKGROUND

Free radical production is elevated in jugular venous blood emerging from the brain in conjunction with carotid endarterectomy. This study explores the relationships between markers for lesion progression in arteriosclerosis, production of radicals and clinical characteristics.

METHODS

The radical production during carotid endarterectomy was studied in 13 patients with an ex vivo spin trap method using OXANOH as a spin trap. MCP-1, ICAM-1, MMP-9 and oxLDL were determined in venous blood samples before, during and after clamping of the carotid artery. Principal component analysis (PCA) as well as partial least square regression analysis (PLS) was applied to interpret the data.

RESULTS

PCA and PLS analysis revealed that high values of MMP-9 and low values of ICAM-1 were associated with high radical production whereas MCP-1 and oxLDL were not correlated to radical production. MMP-9 was elevated at diabetes, high haemoglobin, high leucocyte counts and thrombocyte counts as well as at contralateral stenosis, whereas ICAM-1 showed reversed relationships to these clinical variables. MCP-1 increased during surgery.

CONCLUSIONS

The main finding in our study is that MMP-9 in plasma is asscociated with radical production during carotid endarterectomy, suggesting that this enzyme might be involved in the pathogenesis of brain damage in conjunction with ischaemia-reperfusion.

Circulating oxidized low-density lipoprotein is associated with echolucent plaques in the femoral artery independently of hsCRP in 61-year-old men

OBJECTIVES

The aim of the study was to test the hypothesis that circulating markers of inflammation (high-sensitive C-reactive protein, hsCRP) and oxidative modification of lipids (oxidized low-density lipoprotein, oxLDL) were associated with the occurrence of echolucent rather than echogenic femoral artery plaques in a cross-sectional population based cohort of 513, 61-year-old men.

BACKGROUND

The relationships between circulating oxLDL, hsCRP and the occurrence of echolucent plaques in the femoral artery have not previously been investigated.

METHODS

The levels of circulating oxLDL and hsCRP were determined in plasma by ELISA. Plaque occurrence, size and echogenicity were measured by B-mode ultrasound in the right femoral artery. Assessment of plaque echogenicity was based on the classification (grades 1-4) proposed by Gray-Weale et al.

RESULTS

A higher frequency of echolucent femoral plaques was observed in subjects with the metabolic syndrome and current smokers (p=0.01 and p<0.001, respectively) as well as with increasing levels of oxLDL and hsCRP (p=0.002 and p=0.005, respectively). In a multiple logistic regression analysis oxLDL and current smokers turned out to be independent associated with the presence of echolucent femoral artery plaques.

CONCLUSIONS

The results of the present study support our hypothesis that circulating oxLDL is a marker of an unstable echolucent plaque phenotype in the femoral artery in man.

apoB/apoA–I ratio is related to femoral artery plaques and is predictive for future cardiovascular events in healthy men

OBJECTIVES

The aim of the present study was to investigate the association between serum concentrations of apoB, apoA-I and the apoB/apoA-I ratio and future cardiovascular events in a group of healthy 58-year-old men during 6.6 years of follow-up. A further aim was to investigate the concentrations of apoB, apoA-I and the apoB/apoA-I ratio to the association of plaque occurrence in the carotid and femoral arteries.

BACKGROUND

Previous studies have shown that the apoB/apoA-I ratio is an important cardiovascular risk factor, whereas the association between apoB/apoA-I ratio and presence of atherosclerotic plaques in the carotid and femoral arteries has been less investigated.

METHODS

The carotid and femoral arteries were examined by high-resolution B-mode ultrasound in 391, 58-year-old men identified by screening in the city of Göteborg, Sweden. Assessment of plaque occurrence and measurement of apolipoproteins (apoA-I and apoB) was performed.

RESULTS

Subjects with an apoB/apoA-I ratio >/=0.9 had a significantly increased risk to suffer a cardiovascular event during 6.6 years of follow-up (OR 3.07, 95% CI 1.22-7.71), while no difference in risk for cardiovascular events was observed for subjects with LDL cholesterol >3.4 mmol/L compared to subjects <3.4 mmol/L (OR 1.04, 95% CI 0.37-2.46). A greater risk for plaques in the femoral artery was also observed in subjects with an apoB/apoA-I ratio >/=0.9 compared to subjects <0.9 (OR 3.06, 95% CI 1.22-7.70). In a multiple logistic regression model, both elevated apoB/apoA-I ratio and plaque occurrence in the femoral artery were of significant importance for cardiovascular events during follow-up.

CONCLUSIONS

The results showed that the apoB/apoA-I ratio was associated with arteriosclerosis in the femoral artery, and predicted future cardiovascular events. These observations, and the fact that apoB and apoA-I can be measured in the non-fasting state with high precision, in combination with the finding that LDL cholesterol did not predict cardiovascular disease, support results from other studies that the apoB/apoA-I ratio may be a superior risk marker for cardiovascular disease.

Circulating estradiol is an independent predictor of progression of carotid artery intima-media thickness in middle-aged men

CONTEXT

Estrogen treatment of men with prostate cancer is associated with increased cardiovascular morbidity and mortality; however, the role of endogenous estrogen levels for atherosclerotic disease in men is unknown.

OBJECTIVE

The objective of the study was to determine whether endogenous serum estradiol (E2) levels predict the progression of carotid artery intima-media thickness in men.

DESIGN, SETTING AND PARTICIPANTS

This was a population-based, prospective cohort study (the Atherosclerosis and Insulin Resistance study) conducted in Göteborg, Sweden, among 313 Caucasian men without cardiovascular or other clinically overt diseases. Carotid artery intima-media thickness, an index of preclinical atherosclerosis, was measured by ultrasound at baseline (58 yr of age) and after 3 yr of follow-up. Serum sex hormone levels and cardiovascular risk factors (body mass index, waist to hip ratio, systolic blood pressure, serum triglycerides, plasma c-peptide, and smoking status) were assessed at study entry.

INTERVENTION

There was no intervention.

MAIN OUTCOME MEASURES

Association between baseline total and free E2 levels and progression of carotid intima-media thickness over 3 yr with adjustments for cardiovascular risk factors was measured.

RESULTS

In univariate analyses, both total and free E2 levels at baseline were positively associated with the annual change in intima-media thickness. In linear regression models including E2 and cardiovascular risk factors, low-density lipoprotein and high-density lipoprotein cholesterol and E2 were identified as independent predictors of progression of carotid artery intima-media thickness (total E2 beta = 0.187, P = 0.001; and free E2 beta = 0.183, P = 0.003).

CONCLUSIONS

Circulating E2 is a predictor of progression of carotid artery intima-media thickness in middle-aged men. Further studies are needed to investigate the role of endogenous E2 for incident cardiovascular disease events.

Are serum adiponectin concentrations in a population sample of 64-year-old Caucasian women with varying glucose tolerance associated with ultrasound-assessed atherosclerosis?

OBJECTIVE

To examine whether serum adiponectin concentrations were associated with subclinical atherosclerosis assessed as intima media thickness (IMT) in the carotid arteries in Caucasian women with varying degrees of glucose tolerance.

RESEARCH DESIGN AND METHODS

From a population-based cohort of 64-year-old Swedish women, 533 subjects with type 2 diabetes (DM2, n=177), impaired glucose tolerance (IGT; n=178) or normal glucose tolerance (NGT, n=178) were recruited. Anthropometrics, usual cardiovascular risk factors were examined and ultrasound examination of the carotid arteries was performed.

RESULTS

Women with low adiponectin concentrations were characterized by thick IMT, higher prevalence of DM2, history of previous myocardial infarction, angina pectoris, anti-hypertensive treatment and high body mass index (BMI), waist circumference, plasma insulin, serum triglycerides, fasting glucose, HbA1c, and low serum HDL cholesterol levels. Carotid IMT correlated with HbA1c (r=0.24, P<0.001), waist circumference (r=0.22, P<0.001), plasma insulin (r=0.19, P<0.001), BMI (r=0.18, P<0.001), DM2 (r=0.16, P<0.001), systolic blood pressure (r=0.16, P<0.001), blood glucose (r=0.16, P<0.001), triglycerides (r=0.15, P<0.001), and reversely to adiponectin (r=-0.11, P=0.01), HDL cholesterol (r=-0.13, P=0.004), and alcohol intake (r=-0.087, P<0.05). A more detailed analysis of underlying associations was difficult due to a high co-linearity between these variable.

CONCLUSIONS

Low serum adiponectin concentrations were associated with increased carotid artery IMT, and several risk factors for cardiovascular diseases, mainly those constituting the metabolic syndrome.

Carotid artery intima-media thickness in patients with Type 2 diabetes mellitus and impaired glucose tolerance: a systematic review

AIMS

To review the difference in carotid artery intima media thickness (IMT) between patients with Type 2 diabetes (DM) or impaired glucose tolerance (IGT), and control subjects.

METHODS

Systematic reviews were made in order to identify cross-sectional studies using the ultrasound method. The differences between IMT in DM or IGT and control subjects were calculated. Meta-analysis using random-effects modelling was used to calculate summary measures.

RESULTS

Twenty-three studies included 24,111 subjects; 4019 with DM and 1110 with IGT. In 20 of 21 studies, the diabetic patients had greater carotid artery IMT than the subjects in the control groups. The estimated mean difference in IMT was 0.13 (95% CI: 0.12-0.14) mm. Heterogeneity was observed and likely sources of variation were study size, diabetes duration, and ultrasound method. In three out of nine studies, the IGT patients had significant greater carotid artery IMT than the subjects in the control groups. The estimated mean difference in IMT was 0.04 (95% CI: 0.014-0.071) mm.

CONCLUSIONS

Type 2 diabetes was associated with an 0.13 mm increase in IMT compared with control subjects. In patients with IGT, the increase in IMT was about one-third of that observed in diabetes. The observed difference in IMT can be interpreted as if the diabetes patients were more than 10 years older than the control groups, and that the relative risks of myocardial infarction and stroke were increased by almost 40%, respectively.

Augmented levels of CD44 in macrophages from atherosclerotic subjects: a possible IL-6-CD44 feedback loop?

The cell-adhesion molecule CD44 likely participates in atherosclerosis development. We have shown previously that pro-inflammatory cytokines affect CD44 expression. Therefore, this work examined the role of elevated CD44 levels in human macrophages. Macrophages from human atherosclerotic subjects (n=15) showed elevated levels of CD44 transcript and protein (1.5-fold) compared to matched controls (n=15) (P=0.050 and 0.044, respectively). To test whether genetic factors influence CD44 expression, two single nucleotide polymorphisms in the CD44 gene were analyzed but these were not associated with coronary artery disease. We also examined the potential connection between plasma cytokine levels and CD44 expression. In atherosclerotic subjects, elevated CD44 expression correlates (P=0.012) with enhanced macrophage IL-6 secretion (3.13+/-2.5 pg/mL versus 0.32+/-0.16 pg/mL in controls, P=0.021). Additionally, CD44-deficient mice exhibit less circulating IL-6 than wild-type controls (9.8+/-0.7 pg/mL versus 14.3+/-0.7 pg/mL; P=0.032). Furthermore, IL-6 augments CD44 expression in primary human macrophages after 24 h (P=0.038) and 48 h (P=0.015). Taken together, our data show an IL-6-CD44 feedback loop in macrophages. Such a positive feedback loop may aggravate atherosclerosis development.

Alcohol consumption in relation to metabolic regulation, inflammation, and adiponectin in 64-year-old Caucasian women: a population-based study with a focus on impaired glucose regulation

OBJECTIVE

The aims of this study were to examine alcohol drinking patterns in women with type 2 diabetes, impaired glucose tolerance (IGT), and normal glucose tolerance (NGT) and to investigate whether alcohol intake was associated with improved insulin sensitivity, decreased biomarkers of inflammation, and increased adiponectin levels and if these effects were limited to dysmetabolic women.

RESEARCH DESIGN AND METHODS

From a cohort of 64-year-old Caucasian women, 209 with type 2 diabetes, 205 with IGT, and 186 with NGT were recruited. Alcohol consumption and medication use were assessed by questionnaires. Anthropometric data were collected, and blood glucose, insulin, HDL cholesterol, triglycerides, C-reactive protein, white blood cell count, and serum adiponectin were measured.

RESULTS

Compared with the NGT group, alcohol consumption was lower in the IGT group and lowest in the diabetes group. Mean alcohol intakes of >9.2 and > or =3-9 g/day were positively associated with adiponectin and insulin sensitivity (homeostasis model assessment [HOMA]), respectively, independently of obesity, metabolic control, and other confounders. Alcohol intake correlated negatively with inflammatory markers, although this did not remain after adjustment for HOMA and waist circumference. The inverse associations between alcohol consumption and factors related to the metabolic syndrome such as HOMA, waist circumference, and inflammatory markers were more obvious among women with diabetes and IGT than in healthy women.

CONCLUSIONS

In these women, moderate alcohol consumption showed beneficial associations with the prevalence of type 2 diabetes, IGT, insulin sensitivity, and serum adiponectin. There is a need to clarify whether adiponectin may be a mechanistic link and also to clarify the clinical implications of these observations.

Serum adiponectin in a population sample of 64-year-old women in relation to glucose tolerance, family history of diabetes, autoimmunity, insulin sensitivity, C-peptide, and inflammation

The aim of the study was to describe serum adiponectin levels in a population-based sample of women with different degrees of glucose tolerance and to examine if the variability in serum adiponectin was explained by family history of diabetes, obesity, insulin resistance, glycemia, and inflammation. Repeated oral glucose tolerance tests were used in a screening procedure of a cohort of 64-year-old women to identify those with diabetes mellitus n = 210) and impaired glucose tolerance (n = 201). A random sample of women with normal glucose tolerance (NGT, n = 186) was also included. The examination included history of first-degree relatives with diabetes, anthropometry, measurement of circulating adiponectin, glutamic acid decarboxylase antibodies, blood glucose, HbA1c, insulin, proinsulin, C-peptide, high-sensitivity C-reactive protein, and homeostasis model assessment. Serum adiponectin concentration was lowest among diabetic women, highest in the random-sample NGT group, and intermediate in the impaired glucose tolerance group. This difference was partly explained by homeostasis model assessment, C-peptide, family history, and high-sensitivity C-reactive protein (R2 = 0.33, P < .001), but obesity and glycemia did not contribute to this variability in serum adiponectin. A family history of diabetes was associated with low serum adiponectin concentration independently of obesity, glycemia, or insulin sensitivity (P = .002). Glutamic acid decarboxylase-positive diabetic women (n = 17) had similar serum adiponectin as the NGT group in spite of hyperglycemia. In conclusion, serum adiponectin was lowered in women with type 2 diabetes mellitus, and this difference could only be partly explained by insulin resistance, insulin secretion, family history of diabetes, and inflammation. Family history of diabetes was independently associated with hypoadiponectinemia. Autoimmune diabetic women did not have low adiponectin levels.

Prevalence of diabetes and impaired glucose tolerance in 64-year-old Swedish women: experiences of using repeated oral glucose tolerance tests

OBJECTIVE

The purpose of this study was to describe the prevalence of diabetes and impaired glucose tolerance (IGT) in middle-aged women and to examine the variability and practical use of the oral glucose tolerance test (OGTT) in the screening for IGT and diabetes.

RESEARCH DESIGN AND METHODS

All 64-year-old women living in Göteborg, Sweden, were invited to take part in a screening examination (n = 4,856). Of these, 82% (n = 3,998) responded and 53% (n = 2,595) participated and underwent anthropometric measurements and a 75-g standardized OGTT that was repeated within 2 weeks in those not showing normal glucose tolerance (NGT).

RESULTS

The prevalences of known and new diabetes, IGT at both OGTTs, and impaired fasting glucose were 4.7, 4.8, 14.4, and 6.4%, respectively. Half of the women with diabetes were previously undiagnosed, and 37% of the diagnoses were based on OGTT and diabetes 2-h values at both or one of the two examinations. Women with IGT at both OGTTs, in comparison with those with one impaired and one normal OGTT, had higher BMI, waist girth, and blood pressure. More than 40% of the women showed impaired glucose metabolism.

CONCLUSIONS

Among these women, the prevalence of undetected diabetes was high and repeated OGTTs were needed to identify and not misclassify a considerable proportion of patients. The degree of glucose tolerance impairment and the number of abnormal OGTTs were directly associated with occurrence of components of the metabolic syndrome.

Tesaglitazar, a novel dual peroxisome proliferator-activated receptor alpha/gamma agonist, dose-dependently improves the metabolic abnormalities associated with insulin resistance in a non-diabetic population

AIMS/HYPOTHESIS

Insulin resistance is associated with abnormalities in lipid and glucose metabolism, which are major components of metabolic syndrome and risk factors for vascular disease. This study examined the effect of tesaglitazar (Galida), a novel, dual-acting peroxisome proliferator-activated receptor alpha/gamma agonist, on lipid and glucose metabolism in patients with evidence of insulin resistance.

METHODS

A 12-week, multicentre, randomised, double-blind, placebo-controlled, dose-finding study compared the efficacy and safety of oral tesaglitazar (0.1, 0.25, 0.5 and 1.0 mg/day) and placebo in 390 non-diabetic patients with hypertriglyceridaemia (plasma triglyceride concentration >1.7 mmol/l) and abdominal obesity (waist-to-hip ratio >0.90 for men and >0.85 for women).

RESULTS

A 1.0-mg dose of tesaglitazar reduced fasting triglycerides (the primary endpoint) by 37% (95% CI: -43% to -30%; p<0.0001), non-HDL-cholesterol by 15% (95% CI: -20% to -10%; p<0.0001) and NEFA by 40% (95% CI: -51% to -27%; p<0.0001), and increased HDL-cholesterol by 16% (95% CI: 8 to -24%; p<0.0001). At the end of treatment there was a dose-dependent increase in patients with pattern A LDL particle diameter (40% at baseline vs 87% at 12 weeks for tesaglitazar 1.0 mg). Tesaglitazar produced significant reductions in fasting insulin concentration (-35%; p<0.0001) and plasma glucose concentration (-0.47 mmol/l; p<0.0001). Respiratory infection and gastrointestinal symptoms were the most common adverse events and were similarly frequent in all groups.

CONCLUSIONS/INTERPRETATION

Tesaglitazar was well tolerated and produced significant, dose-dependent improvements in lipid and glucose metabolism and insulin sensitivity. Tesaglitazar may have the potential to prevent vascular complications and delay progression to diabetes in these patients.

A proteomic study of the apolipoproteins in LDL subclasses in patients with the metabolic syndrome and type 2 diabetes

The exchangeable apolipoproteins present in small, dense LDL (sdLDL) and large, buoyant LDL subclasses were evaluated with a quantitative proteomic approach in patients with the metabolic syndrome and with type 2 diabetes, both with subclinical atherosclerosis and the B LDL phenotype. The analyses included surface-enhanced laser adsorption/ionization, time-of-flight mass spectrometry, and subsequent identification by mass spectrometry or immunoblotting and were carried out in LDL subclasses isolated by ultracentrifugation in deuterium oxide gradients with near physiological salt concentrations. The sdLDLs of both types of patients were enriched in apolipoprotein C-III (apoC-III) and were depleted of apoC-I, apoA-I, and apoE compared with matched healthy controls with the A phenotype. The LDL complexes formed in serum from patients with diabetes with the arterial proteoglycan (PG) versican were also enriched in apoC-III. In addition, there was a significant correlation between the apoC-III content in sdLDL in patients and the apparent affinity of their LDLs for arterial versican. The unique distribution of exchangeable apolipoproteins in the sdLDLs of the patients studied, especially high apoC-III, coupled with the augmented affinity with arterial PGs, may contribute to the strong association of the dyslipidemia of insulin resistance with increased risk for cardiovascular disease.

Regulation and splicing of scavenger receptor class B type I in human macrophages and atherosclerotic plaques

BACKGROUND

The protective role of high-density lipoprotein (HDL) in the cardiovascular system is related to its role in the reverse transport of cholesterol from the arterial wall to the liver for subsequent excretion via the bile. Scavenger receptor class B type I (SR-BI) binds HDL and mediates selective uptake of cholesterol ester and cellular efflux of cholesterol to HDL. The role of SR-BI in atherosclerosis has been well established in murine models but it remains unclear whether SR-BI plays an equally important role in atherosclerosis in humans. The aim of this study was to investigate the expression of SR-BI and its isoforms in human macrophages and atherosclerotic plaques.

METHODS

The effect of hypoxia and minimally modified low-density lipoprotein (mmLDL), two proatherogenic stimuli, on SR-BI expression was studied in human monocyte-derived macrophages from healthy subjects using real-time PCR. In addition, SR-BI expression was determined in macrophages obtained from subjects with atherosclerosis (n = 15) and healthy controls (n = 15). Expression of SR-BI isoforms was characterized in human atherosclerotic plaques and macrophages using RT-PCR and DNA sequencing.

RESULTS

SR-BI expression was decreased in macrophages after hypoxia (p < 0.005). In contrast, SR-BI expression was increased by exposure to mmLDL (p < 0.05). There was no difference in SR-BI expression in macrophages from patients with atherosclerosis compared to controls. In both groups, SR-BI expression was increased by exposure to mmLDL (p < 0.05). Transcripts corresponding to SR-BI and SR-BII were detected in macrophages. In addition, a third isoform, referred to as SR-BIII, was discovered. All three isoforms were also expressed in human atherosclerotic plaque. Compared to the other isoforms, the novel SR-BIII isoform was predicted to have a unique intracellular C-terminal domain containing 53 amino acids.

CONCLUSION

We conclude that SR-BI is regulated by proatherogenic stimuli in humans. However, we found no differences between subjects with atherosclerosis and healthy controls. This indicates that altered SR-BI expression is not a common cause of atherosclerosis. In addition, we identified SR-BIII as a novel isoform expressed in human macrophages and in human atherosclerotic plaques.

The metabolic syndrome in middle-aged men according to different definitions and related changes in carotid artery intima-media thickness (IMT) during 3 years of follow-up

OBJECTIVES

To examine the occurrence over time of the metabolic syndrome (MetS) according to different definitions and the relation to change during follow-up in carotid artery intima-media thickness (IMT), measured by ultrasound.

DESIGN

A cohort of 316, originally 58-year-old men, initially free of diabetes and cardiovascular disease, was followed for 3.2 +/- 0.2 years. IMT was measured bilaterally by high-resolution B-mode ultrasound at baseline and follow-up. The MetS was classified according to slightly modified World Health Organization (WHO) and National Cholesterol Education Program (NCEP) criteria.

RESULTS

In 88% WHO and NCEP definitions resulted in identical classifications. IMT was larger both at baseline and after 3 years in men fulfilling the criteria for the MetS, according to either of the definitions, compared to those without factors in the syndrome. Men who fulfilled the WHO criteria for the MetS, at the initial and final examination showed a statistically significant increase in carotid artery IMT during the study [76 (95% CI: 14-130) microm, n = 37]. Men fulfilling the WHO criteria for the MetS at baseline tended to have a larger annual increase in IMT than those not fulfilling the criteria or having no risk factors in the syndrome.

CONCLUSIONS

More than 10% of the men had the MetS both at baseline and after 3 years, and this was associated with an increase in IMT using the WHO definition. Several of the components included in the MetS deteriorated during follow-up, i.e. body mass index (BMI), waist-to-hip ratio (WHR), waist circumference, blood glucose and blood pressure.