Cholesterol efflux and macrophage polarization in human adipose tissue

The pro-inflammatory status of adipose tissue (AT) has been found to be related to reverse cholesterol transport (RCT) from peritoneal macrophages. However, this finding was made in experimental models using induced peritonitis and isolated peritoneal macrophages of animals. This experimental relationship is in agreement with RCT changes in man in two extreme situations, sepsis or cardiovascular complications. Given the above, we sought to test RTC in relationship to macrophage polarization in the visceral AT (VAT) of living kidney donors (LKDs) and the effect of conditioned media obtained from their AT. The influence of ATCM on CE capacity was first assessed in an experiment where standard plasma was used as cholesterol acceptor from [14C] cholesterol labeled THP-1 cells. Conditioned media as a product of LKDs’ incubated AT showed no effect on CE. Likewise, we did not find any effect of individual plasma of LKDs on CE when individual plasma of LKDs were used as acceptors. On the other hand, we documented an effect of LKDs’ adipose cell size on CE. Our results indicate that the pro-inflammatory status of human AT is not likely induced by disrupted RCT but might be influenced by the metabolic status of LKDs’ adipose tissue.

Adipose tissue macrophages and atherogenesis – a synergy with cholesterolaemia

Excessive LDL cholesterol concentration together with subclinical inflammation, in which macrophages play a central role, are linked pathologies. The process starts with the accumulation of macrophages in white adipose tissue and the switch of their polarization toward a pro-inflammatory phenotype. The proportion of pro-inflammatory macrophages in adipose tissue is related to the main risk predictors of cardiovascular disease. The cholesterol content of phospholipids of cell membranes seems to possess a crucial role in the regulation of membrane signal transduction and macrophage polarization. Also, different fatty acids of membrane phospholipids influence phenotypes of adipose tissue macrophages with saturated fatty acids stimulating pro-inflammatory whereas ω3 fatty acids anti-inflammatory changes. The inflammatory status of white adipose tissue, therefore, reflects not only adipose tissue volume but also adipose tissue macrophages feature. The beneficial dietary change leading to an atherogenic lipoprotein decrease may therefore synergically reduce adipose tissue driven inflammation.

Adipose tissue macrophages and atherogenesis – a synergy with cholesterolaemia

Excessive LDL cholesterol concentration together with subclinical inflammation, in which macrophages play a central role, are linked pathologies. The process starts with the accumulation of macrophages in white adipose tissue and the switch of their polarization toward a pro-inflammatory phenotype. The proportion of pro-inflammatory macrophages in adipose tissue is related to the main risk predictors of cardiovascular disease. The cholesterol content of phospholipids of cell membranes seems to possess a crucial role in the regulation of membrane signal transduction and macrophage polarization. Also, different fatty acids of membrane phospholipids influence phenotypes of adipose tissue macrophages with saturated fatty acids stimulating pro-inflammatory whereas ω3 fatty acids anti-inflammatory changes. The inflammatory status of white adipose tissue, therefore, reflects not only adipose tissue volume but also adipose tissue macrophages feature. The beneficial dietary change leading to an atherogenic lipoprotein decrease may therefore synergically reduce adipose tissue driven inflammation.

Immunological analysis of carotid artery plaques and its relationship to the gray scale median value obtained by ultrasound

Introduction

A gray scale median (GSM) value established by ultrasound could potentially reflect atherosclerotic plaque stability in carotid arteries, this stability could be also assessed by the measurements potential pro- and antiiflammatory characteristics of macrophages detected in the plaque. We analyzed association between the GSM value and several macrophage characteristics in carotid artery plaques.

Methods

Twenty-four patients (14 men, mean age 66.4±4.4 years) underwent ultrasound scan to determine the GSM value in maximum of one day before carotid endarterectomy. Immediately after removal, atherosclerotic plaques were processed for and analyzed by flow cytometric analysis. CD14, CD16, CD36, CD163 and CD206 markers were used to evaluate macrophage polarization.

Results

The GSM value ranged from 0 to 146. The majority of macrophages were established as CD14+CD16+. These macrophages also often co-expressed CD206, CD36 and CD163 while the expression of CD206 and CD36 in CD14+CD16- cells was lower and the expression of CD163 was almost negligible. Pro- and antiiflammatory macrophage phenotypes based on combination of different expression of CD markers did not correlate with the GSM value. In addition, no significant relationship was found between the GSM value and the presence of traditional cardiovascular risk factors. In patients with history of diabetes mellitus significantly lower percentage of CD14+CD16+CD206- macrophages was observed than in non.diabetics (p<0.05).

Conclusion

The GSM value did not correlate with potential pro- and antiiflammatory macrophage phenotypes. In addition, in contrast to published data, no relationship was found between the GSM value and the presence of cardiovascular risk factors

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Supported by Ministry of Health, Czech Republic - conceptual development of research organization; Thanks to courtesy of professor Andrew Nicolaides we used software developed by him and his colleagues to assess structure of carotid plaques by ultrasound.

Global DNA methylation in rats´ liver is not affected by hypercholesterolemic diet

Increased plasma cholesterol levels are listed between the major atherosclerosis risk factors. The final plasma cholesterol levels result from the interplay between the genetic and environmental (diet, physical activity) factors. Little is known, how dietary factor influence epigenetics. We have analyzed, if an over-generation feeding of rat with cholesterol influences total liver-DNA methylation, and if total liver-DNA methylation differ between the different rat strains (Prague hereditary hypercholesterolemic rats, Prague hereditary hypertriglyceridemic rats and Wistar Kyoto rats). The animals were feed with high fat (additional 5 % over normal capacity) high cholesterol (2 %) diet for 14 days. DNA methylation in the liver tissue in different generations was analyzed using the liquid chromatography coupled with tandem mass spectrometry. We have not observed any significant changes in total liver-DNA methylation over the 9 generations of animals feed by fat/cholesterol enriched diet. Additionally, there were no differences in DNA methylation between different rat strains. In animal model, the dietary changes (hypercholesterolemic diet) not significantly influence the total DNA methylation status within the liver.

Adipose tissue collection from a living kidney donor; an experimental model for the research of atherosclerosis

Thanks to an increased number of living-donor kidney transplants the IKEM transplant program offers the possibility of obtaining adipose tissue for scientific purposes from patients with varying degrees of atherosclerosis. Surgery mainly addresses vascular complications of this disease. On the other hand, surgery may also be the reason for the development and acceleration of atherosclerosis - for instance, acceleration of atherosclerosis in the living kidney donor, particularly if, although meeting internationally recognized donation criteria, the donor actually suffers from metabolic syndrome. The effort to refine the examinations of living kidney donors in terms of eliminating the risk of developing atherosclerosis is a long-term project. The aims are to determine the risk factors for living kidney donors and to prevent long-term complications after donation. The paper gives a detailed description of the technique of adipose tissue collection from a living kidney donor and of the experimental model for the research of atherosclerosis.The project has the potential to increase the safety of living kidney donation and to enhance our present knowledge of atherosclerosis development mechanisms.

Human genome evolution and development of cardiovascular risk factors through natural selection

Impressive advances in molecular genetic techniques allow to analyze the effects of natural selection on the development of human genome. For example, the trend towards blonde hair and blue eyes was documented. The approach to analyze possible effects of natural selection on the evolution of recent phenotypes with high risk of cardiovascular disease has not been described yet. A possible effect on the evolution of two main risk factors - hypercholesterolemia and hypertension - is presented. The close relationship of non-HDL cholesterol blood concentration to the proportion of pro-inflammatory macrophages in human visceral adipose tissue might be a result of long-lasting natural selection. Individuals with higher proportion of this phenotype might also display a higher ability to fight infection, which was very common in human setting from prehistory until Middle Ages. Successful battle against infections increased the probability to survive till reproductive age. Similar hypothesis was proposed to explain frequent hypertension in African Americans. A long-lasting selection for higher ability to conserve sodium during long-term adaptation to low sodium intake and hot weather was followed by a short-term (but very hard) natural selection of individuals during transatlantic slave transport. Only those with very high capability to retain sodium were able to survive. Natural selection of phenotypes with high plasma cholesterol concentration and/or high blood pressure is recently potentiated by high-fat high-sodium diet and overnutrition. This hypothesis is also supported by the advantage of familial hypercholesterolemia in the 19th century (at the time of high infection disease mortality) in contrast to the disadvantage of familial hypercholesterolemia during the actual period of high cardiovascular disease mortality.

Experimental models of hyperlipoproteinemia and atherosclerosis

The first experimental model of atherosclerosis (in rabbits) is more than hundred years old. Several animal species have been used to produce hyperlipoproteinemia and possible atherosclerosis. The gene manipulation produced the most used models recently. This review acknowledges the extensive study of atherosclerotic changes in experimental models of hyperlipoproteinemia and atherosclerosis to come to light thus far and the purpose here is not only to summarize the published data but also to try to add some details of our experience in using these models. In addition to rabbit (the old but also improved model by reno-vascular hypertension) dog, birds, pig, hamster, mice, rat and non-human primate's animal models are described. The gene manipulation produced the most used models two decades ago. Germline genetically engineered (without apoE or LDL receptor genes) animals have become the most used models producing atherosclerotic changes in the aorta. Recent new models also producing atherosclerotic changes but without germline genetic manipulation are also described.

Adipose tissue and atherosclerosis

High-energy intake which exceeds energy expenditure leads to the accumulation of triglycerides in adipose tissue, predominantly in large-size adipocytes. This metabolic shift, which drives the liver to produce atherogenic dyslipidemia, is well documented. In addition, an increasing amount of monocytes/macrophages, predominantly the proinflammatory M1-type, cumulates in ectopic adipose tissue. The mechanism of this process, the turnover of macrophages in adipose tissue and their direct atherogenic effects all remain to be analyzed.

The effect of ectopic fat on graft function after living kidney transplantation

Renal transplantation is associated with a large number of risk factors that can have an influence on early renal graft function (ERGF). One of these factors could be the increasing number of obese kidney donors. The mechanisms of reduced ERGF in obese kidney donors are still poorly understood. To that end, we compared ERGF in recipients with body mass index (BMI), perivascular fat and plasma inflammation markers of live kidney donors. We hypothesized that the BMI of donors would negatively correlate with an average increase of glomerular filtration rate (GFR) and that it would also be associated with increased perivascular and plasma inflammation markers in the first seven days after transplantation. Between January 2013 and December 2014, some 58 living kidney transplantation pairs were included in the study. Donor and recipient demographic data, preoperative BMI, blood C-reactive protein (CRP) and adiponectin levels, perivascular adipose tissue (PAT) samples and recipient blood creatinine levels were analyzed. The median CRP of donors was 0.68 mg/l (max: 8.66 mg/l, min: 0.33 mg/l), the median of M1 macrophages (CD14+CD16+) in one gram of PAT was 5940 (max: 41 100, min: 248) and the median of adiponectin was 411 930 pg/ml (max: 14 217 000, min: 167 300) in plasma. We did not find any association between early renal graft function and the percentage of M1 macrophages in donor perirenal adipose tissue (p=0.83, r=0.03, n=58), adiponectin (p=0.65, r=0.06, n=58) or CRP (p=0.16, r=0.2, n=58) in plasma. The obesity level of donors, expressed as BMI, did not correlate with early renal graft function in the first seven days after transplantation. The associations between ERGF and plasma and perivascular fat inflammation markers were not significant. We confirmed a negative correlation between the BMI of recipients and an average increase of GFR in the first seven days after transplantation (p<0.02, r=-0.325, N=58). We confirmed a negative correlation of adiponectin plasma concentration to the BMI of donors.

Macrophage phenotypes in the adipose tissue of postmenopausal women

Atherosclerosis pathology is the interplay between high intravascular LDL particle concentration and monocyte/macrophage presence within the sub-endothelial space of the artery. In this project, phenotypes of macrophages connected with subclinical inflammation in adipose tissue of living kidney donors were studied. Samples of subcutaneous adipose tissue of living kidney donors (n=36) were exposed to collagenase. Stromal vascular fraction (SVF) was eluted from the samples, then labeled with monoclonal antibodies (anti-CD14 and anti-calprotectin), conjugated with fluorochromes and analyzed by flow cytometry. The positive correlation between the number of total macrophages and calprotectin-positive macrophages with BMI in the subcutaneous adipose tissue of postmenopausal women was demonstrated (p<0.05; R=0.43 and p<0.01; R=0.60), whereas no positive correlation in premenopausal women and men was shown. In conclusion, we documented a significant effect of BMI increase on the presence of total macrophages in adipose tissue of postmenopausal women, in contrast to premenopausal women. This difference was much more pronounced when proinflammatory macrophages with membrane-bound calprotectin were analyzed.

Rs6922269 marker at the MTHFD1L gene predict cardiovascular mortality in males after acute coronary syndrome

Myocardial infarction (MI) is the leading cause of death in industrialized countries. All the traditional risk factors for MI are responsible for approximately 50% of cases of MI cases. Attention therefore has recently focused on genetic variants that are not associated with conventional risk factors. One of them is the marker rs6922269, which has been suggested as a risk factor for development of MI in Western populations. We analyzed the relationship between rs6922269 variant on MTHFD1L gene and (i) risk of the acute coronary syndrome (ACS) in the Czech population and (ii) mortality in 7 years follow up. Rs6922269 (G>A) variant was analyzed (CR 99.3% for patients and 98.0% for controls) by PCR-RFLP in consecutively examined 1614 men and 503 women with ACS (age below 65 years) and in population-based controls--1191 men and 1368 women (aged up to 65 years). ANOVA and Chi square were used for statistical analysis. The genotype frequencies were almost identical (P=0.87) in the ACS patients and in controls and no differences were observed, if males (P=0.73) and females (P=0.93) were analysed separately. In addition, rs6922269 polymorphism was not associated with the classical risk factors (dyslipidemia, hypertension, obesity, smoking, diabetes) in control population. Cardiovascular mortality was significantly higher in males, carriers of the AA genotype (P<0.001, OR 2.52, 95% CI 1.40-4.55, for AA vs. +G). We conclude, that rs6922269 variant at MTHFD1L gene could be an important prognostic factor for cardiovascular mortality in patients after ACS.

Postprandial triglyceridemia after single dose of alcohol in healthy young men

BACKGROUND AND AIMS

Moderate alcohol consumption provides protection against cardiovascular disease primarily due to increase of HDL-cholesterol. However, it also has some adverse effects on metabolism of triglycerides (TG). Therefore, we addressed the question how a single dose of alcohol affects postprandial lipemia and activities of two enzymes playing a critical role in regulation of triglyceridemia, lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL).

METHODS AND RESULTS

Eight healthy volunteers were given a single dose of alcohol (vodka; 0.6 g of ethanol/kg of body weight) together with a fat load (0.7 g of fat/kg of body weight) in an experimental breakfast or together with dinner 12 h before the experimental breakfast. In comparison to control experiment, alcohol given with breakfast induced increased and prolonged postprandial response of triglyceride-rich lipoproteins (TRL; d < 1.006 g/ml). At the same time TG accumulated also in intermediate density lipoproteins (IDL; d 1.006-1.019 g/ml). Alcohol given in the evening before the experiment increased fasting TG concentration but did not affect changes in TRL and IDL concentrations. LPL activity measured both in vivo using intravenous fat tolerance test and in vitro and HTGL activity were determined at the end of experiments (after 7.5 h of postprandial lipemia study). Neither was affected by a single dose of alcohol.

CONCLUSIONS

Single dose of alcohol induces immediate and profound changes in metabolism of TRL and IDL. The same dose of alcohol given 12 h before meal does affect baseline TG concentration but not the postprandial changes of triglyceridemia.

Association between a marker on chromosome 9 and acute coronary syndrome. confirmatory study on Czech population

Myocardial infarction (MI) is the leading cause of death in industrialized countries. All the classical risk factors for MI are responsible for approximately 50 % of MI cases. Attention has therefore recently been attracted to those genetic variants that are not associated with conventional risk factors. One of them is the marker rs10757274 in the "genefree" zone on chromosome 9, which has been repeatedly recognized as a risk factor for development of MI in Western populations. We analysed the relationship between the rs10757274 variant on chromosome 9 and risk of the acute coronary syndrome (ACS) in Czech population. The rs10757274 (A > G) variant was successfully analysed (CR = 99.4 % for patients and 98.4 % for controls) by PCR-RFLP in consecutively examined 1,046 men and 281 women with ACS (age below 65 years) and in population-based controls - 1,162 men and 1,355 women (aged up to 65 years). ANOVA and χ2 were used for statistical analysis. We confirmed that GG homozygotes are more frequent (codominant model of analysis) among patients with myocardial infarction than in the control group both in men (28.5 % vs. 22.0 %, P = 0.0001, OR 1.73, 95 % CI 1.36-2.19) and women (32.0 % vs. 24.6 %, P = 0.02, OR 1.62, 95 % CI 1.13-2.34). However, rs10757274 polymorphism was not associated with the classical risk factors either in control population or in ACS patients. We conclude that the rs10757274 variant at 9p23.1 is an important genetic risk factor for ACS development in the Czech population.

The association between subclinical atherosclerosis in carotid arteries and Connexin 37 gene polymorphism (1019C>T; Pro319Ser) in women

AIM

The aim of our study was to evaluate a possible association between subclinical atherosclerosis in carotid arteries and the connexin 37 gene polymorphism (1019C>T; Pro319Ser) in a population of urban and rural women.

METHODS

A 5% population sample of urban women aged 45-54 years (N.=896) and a 1% representative sample of rural women aged 33-72 years (N.=152) were examined using an identical protocol and genotyped for Cx37 gene polymorphism. The association between the Cx37 polymorphism and intima-media thickness in common carotid arteries measured by ultrasound (CIMT) was studied.

RESULTS

We have found a different pattern of the effect of the Cx37 gene on CIMT with regard to fasting glycemia with significant interaction between fasting glycemia and Cx37 gene on CIMT (test for equality of slopes P<0.0001). In addition, we also detected potential threshold effect of fasting glycemia at the concentration of 5.5 mmol/L (ANCOVA; P=0.026). Carriers of TT genotype showed protection against subclinical atherosclerosis if their fasting glycemia was above 5.5 mmol/L.

CONCLUSION

In women with higher fasting glycemia TT genotype of Cx37 polymorphism was protective against subclinical atherosclerosis. Therefore, the Cx37 gene may exert completely different effects in the artery wall, depending on glycemia.

Proinflammatory status, genetics and atherosclerosis

Over the last decade, C-reactive protein concentration analyzed by the high sensitivity method (hsCRP) has been proven as a marker of premature atherosclerosis. Concentration exceeding 2 mg/l represents an increased individual risk of myocardial infarction and stroke but strict application of this borderline is complicated by relations of CRP concentrations to other risk factors of cardiovascular diseases. In a large 1 % representative sample of the Czech population, a positive relation of hsCRP to BMI, a waist circumference and triglyceride concentration was documented. Substantial sex differences were found in its relationship to age. Whereas it is continuously increasing in men, this increase appears in women only after menopause. A substantial decrease of body weight and visceral fat volume by increased physical activity is accompanied by significant decrease of hsCRP in young obese women. This decrease was not related to a change of interleukin-6 concentration, although it is supposed to regulate CRP production. CRP concentration is partly under genetic control as a higher concentration in young siblings of probands with proved coronary atherosclerosis was documented. The participation of genes related to lipoprotein metabolism (genes for apolipoprotein CI and apolipoprotein E) influence hsCRP concentrations. We hypothesized that an increased concentration of hsCRP represents a certain marker of proinflammatory status related to central obesity and triglyceride metabolism and it might be related to individual properties of monocytes in atherogenesis.

Prague hereditary hypercholesterolemic (PHHC) rat - a model of polygenic hypercholesterolemia

Prague hereditary hypercholesterolemic (PHHC) rat - rat strain crossbred from Wistar rats - is a model of hypercholesterolemia induced by dietary cholesterol. Importantly, no bile salts and/or antithyroid drugs need to be added to the diet together with cholesterol to induce hypercholesterolemia. PHHC rats have only modestly increased cholesterolemia when fed a standard chow and develop hypercholesterolemia exceeding 5 mmol/l on 2 % cholesterol diet. Most of the cholesterol in hypercholesterolemic PHHC rats is found in VLDL that become enriched with cholesterol (VLDL-C/VLDL-TG ratio > 1.0). Concurrently, both IDL and LDL concentrations rise without any increase in HDL. PHHC rats do not markedly differ from Wistar rats in the activities of enzymes involved in intravascular remodelation of lipoproteins (lipoprotein and hepatic lipases and lecithin:cholesterol acyltransferase), LDL catabolism, cholesterol turnover rate and absorption of dietary cholesterol. The feeding rats with cholesterol diet results in development of fatty liver in spite of suppression of cholesterol synthesis. However, even though cholesterolemia in PHHC rats is comparable to human hypercholesterolemia, the PHHC rats do not develop atherosclerosis even after 6 months on 2 % cholesterol diet. Importantly, the crossbreeding experiments documented that hypercholesterolemia of PHHC rats is polygenic. To identify the genes that may be involved in pathogenesis of hypercholesterolemia in this strain, the studies of microarray gene expression in the liver of PHHC rats are currently in progress.

Life style change and reverse cholesterol transport in obese women

HDL cholesterol resp. apolipoprotein A1 concentrations are tools to estimate individual CVD risk, although only a part of HDL particles participate in reverse cholesterol transport (RCT). This discrepancy was analyzed in life style change based on increase of physical activity and dietary counseling. Efflux of cholesterol from pre-labeled macrophages to plasma acceptors of tested individuals was used as an RCT measure. Changes of lipoprotein parameters, glucose, fasting insulin concentrations and RCT were analyzed in 15 obese women after 9-week intervention consisted of 5 sessions of increased physical activity per week. Controlled increase in physical activity for 9 weeks induced a decrease of body weight averaging 9 kg (ranged from 2.3 to 15.5 kg). The intervention leads to significant decreases of triglycerides, apoprotein A1 and apoprotein B concentration, whereas total cholesterol, LDL cholesterol and HDL cholesterol did not change significantly. The increase of RCT was not significant, but there was highly significant negative correlation between individual decrease of body weight and an increase of RCT. Significant increase of RCT was found in 13 persons with a weight reduction more than 3.5 kg. Substantial weight loss is necessary to increase RCT.

Why we are not able to find the coronary heart disease gene - apoE as an example

The apoprotein E gene ranks among the most discussed candidate genes for cardiovascular disease. We studied whether the association between apoprotein E gene polymorphism and manifestation of acute coronary syndrome is modulated by the presence/absence of traditional cardiovascular risk factors. The population under study were 1066 patients (men under 65 years) admitted between 2006- 2009 to five coronary care units in Prague (GENetic DEtermination of Myocardial Infarction in Prague) and the control population (1066 age-matched men selected from the Czech population sample). The frequency of disadvantage genotype E4+ was significantly higher (P < 0.01) in acute coronary syndrome patients (22.38 %) than in controls (16.76 %). When the acute coronary syndrome group was step by step limited to non-smokers, non-diabetics and normotensive individuals, the odds ratio displayed a gradual increase from 1.35 (for the entire group) through 1.48 (non-smokers), 1.53 (non-smokers+non-diabetics) to 1.71 (non-smokers+non-diabetics+normotensives). The effect of the apoprotein E gene on the individual risk of acute coronary syndrome is nonhomogenous within the patient groups. This association of apoprotein E gene with acute coronary syndrome is strongly modified by the presence/absence of traditional cardiovascular factors of atherosclerosis in a high-risk Czech population.

Antiatherogenic Effect of Simvastatin Is Not Due to Decrease of LDL Cholesterol in Ovariectomized Golden Syrian Hamster

The changes of the composition of blood lipoproteins caused by menopause could also change the effect of hypolipidemic therapy. Using an experimental model we studied the changes of serum lipids and the effect of immediate or delayed treatment with simvastatin on atherosclerosis after surgical menopause. Female golden Syrian hamster aged 6 months were fed hypercholesterolemic diet during the whole study. Atherosclerotic changes in thoracic and abdominal aortas were assessed by stereomicroscopic method after 12 weeks. Four experimental groups were studied: sham-operated animals (n=5), ovariectomized animals (n=9), ovariectomized animals treated for 12 weeks (n=10), and ovariectomized animals treated 4 weeks after ovariectomy for 8 weeks (n=9). The dose of simvastatin was 10 mg/kg of body weight. After 12 weeks, ovariectomized animals had tenfold higher concentration of triglycerides in LDL fraction and significantly higher prevalence of atherosclerosis than animals without ovariectomy. Treatment with simvastatin substantially decreased the prevalence of atherosclerotic changes, but otherwise did not change individual serum lipids including LDL cholesterol. However, it improved proportions of pro- and antiatherogenic serum lipids mainly by the increase of HDL cholesterol. The timing of simvastatin treatment had no significant effect on atherosclerotic changes or lipid parameters. Simvastatin treatment partly prevented atherosclerotic changes induced by ovariectomy. This effect was not mediated by decrease of LDL cholesterol, but by increase in HDL cholesterol.

May alcohol-induced increase of HDL be considered as atheroprotective?

It is well known that the consumption of moderate doses of alcohol leads to the increase of HDL-cholesterol (HDL-C). Atheroprotectivity of HDL particles is based primarily on their role in reverse cholesterol transport (RCT). In the study with a cross-over design 13 male volunteers were studied in two different regimens: i) drinking of 36 g alcohol daily and ii) drinking only non-alcoholic beverages, to test whether alcohol-induced increase of HDL cholesterol can affect cholesterol efflux (CHE) from cell culture of labeled human macrophages. Alcohol consumption induced significant (p < 0.05) increases of HDL cholesterol from 1.25 +/- 0.32 to 1.34 +/- 0.38 mmol/l and Apo A1 from 1.34 +/- 0.16 to 1.44 +/- 0.19 g/l. These changes were combined with a slight increase of cholesterol efflux from 13.8 +/- 2.15 to 14.9 +/- 1.85 % (p = 0.059). There were significant correlations between individual changes of HDL-C and Apo A1 concentrations and individual changes of CHE (0.51 and 0.60, respectively). In conclusion, moderate alcohol consumption changes the capacity of plasma to induce CHE only at a border line significance.

No relation between angiotensin‐converting enzyme gene polymorphism and smoking dependence

BACKGROUND

Smoking as a major risk factor for development of cancer and cardiovascular disease is thought to be partially genetically determined. The aim of this study was to investigate whether there is an association between insertion/deletion (I/D) polymorphism in angiotensin-converting enzyme (ACE) and smoking status and the number of cigarettes smoked per week.

METHODS

Using polymerase chain reaction, I/D polymorphism was evaluated in the ACE gene in 1204 male and 1375 female representative Caucasians. Information about smoking status and number of cigarettes smoked per week was collected via a questionnaire.

RESULTS

Frequencies of the alleles and genotypes of ACE I/D polymorphism did not differ between smokers, past smokers and individuals who had never smoked. No association was found between ACE I/D polymorphism and the number of cigarettes smoked per week, either in males or in females.

CONCLUSION

I/D polymorphism in the ACE gene does not play any role in genetic determination of predisposition to smoking.

Proinflammatory status, genetics and atherosclerosis

Over the last decade, C-reactive protein concentration analyzed by the high sensitivity method (hsCRP) has been proven as a marker of premature atherosclerosis. Concentration exceeding 2 mg/l represents an increased individual risk of myocardial infarction and stroke but strict application of this borderline is complicated by relations of CRP concentrations to other risk factors of cardiovascular diseases. In a large 1 % representative sample of the Czech population, a positive relation of hsCRP to BMI, a waist circumference and triglyceride concentration was documented. Substantial sex differences were found in its relationship to age. Whereas it is continuously increasing in men, this increase appears in women only after menopause. A substantial decrease of body weight and visceral fat volume by increased physical activity is accompanied by significant decrease of hsCRP in young obese women. This decrease was not related to a change of interleukin-6 concentration, although it is supposed to regulate CRP production. CRP concentration is partly under genetic control as a higher concentration in young siblings of probands with proved coronary atherosclerosis was documented. The participation of genes related to lipoprotein metabolism (genes for apolipoprotein CI and apolipoprotein E) influence hsCRP concentrations. We hypothesized that an increased concentration of hsCRP represents a certain marker of proinflammatory status related to central obesity and triglyceride metabolism and it might be related to individual properties of monocytes in atherogenesis.

Apolipoprotein E Arg136 --> Cys in individuals with premature myocardial infarction

Coronary artery disease is a serious health problem worldwide caused by interactions between genetic and environmental risk factors. One of the candidate genes is the gene for apolipoprotein E. We present a case report of two young smoking and obese carriers (man 45 years and woman 32 years old) of the apolipoprotein E (p.Arg136Cys) mutation, but with no severe dyslipidaemias detected among 1,671 survivors (1,483 men, 188 women, aged 21-75 years) of acute coronary syndrome screened for genetic and traditional cardiovascular risk factors. Between acute coronary syndrome survivors, the mutation has not yet been described. Even though this mutation raises suspicion to be a risk factor for cardiovascular disease (based on previous publications), its frequency was very low and similar to the control population (12 detected carriers of the mutation within the 9,386 screened individuals). Therefore, whether this rare mutation is causal for the development of myocardial infarction needs to be further evaluated.

Apolipoprotein A5 in health and disease

High plasma levels of triglycerides (TG) are an independent risk factor in the development of cardiovascular disease, with about 50 % of the final levels being determined genetically. Apolipoprotein A5 (APOA5) is the last discovered member of the apolipoprotein APOA1/C3/A4 gene cluster, found by comparative sequencing analysis. The importance of APOA5 gene for determination of plasma triglyceride levels has been suggested after development of transgenic and knock-out mice (transgenic mice displayed significantly reduced TG, whereas knock-out mice had high TG). In Czech population, alleles C-1131 and Trp19 are associated with elevated levels of plasma TG and higher risk of myocardial infarction development. These alleles also play some role in nutrigenetics and actigenetics of lifestyle interventions leading to the plasma cholesterol changes as well as in the pharmacogenetics of statin treatment. On the contrary, APOA5 mutations detected in Czech population did not show strict effect on plasma TG levels. Val153 → Met variant exhibit the sexspecific effect of HDL-cholesterol levels. The suggested roles of APOA5 variants in determination of the plasma remnant particles, plasma concentrations of C-reactive protein or some anthropometrical parameters were excluded.

Changes of plasma lipids during weight reduction in females depends on APOA5 variants

BACKGROUND

Apolipoprotein A5 (APOA5) is a determinant of plasma lipids, and its role in body mass index (BMI) determination is discussed. This study was aimed at the investigation of the relationship between common APOA5 gene variants and body weight/plasma lipid decrease in overweight females.

METHODS

We analyzed 98 unrelated overweight and obese nondiabetic Czech females (BMI >27.5). APOA5 T-1131-->C and Ser19-->Trp variants were genotyped. Before and after 9 weeks of lifestyle modification, biochemical and anthropometrical measurements and assessment of nutritional intake were performed. The lifestyle modification program consisted of a reduction in energy intake and an exercise program (aerobic exercise 4 times per week, 60 min each).

RESULTS

The mean age of the participants was 30.7 +/- 3.7 years, the mean BMI before the intervention was 31.4 +/- 3.8 and the weight loss was 5.9 +/- 2.5 kg (7 +/- 3%). There were 86 T-1131T homozygotes and 12 carriers of the C-1131 allele and 82 Ser19Ser homozygotes and 16 carriers of the Trp19 allele, respectively; 72 females had the commonest T-1131T/Ser19Ser haplotype. No significant association between BMI decrease and APOA5 variants was found, but T-1131T carriers have a significantly higher body weight both before and after the intervention (p < 0.05; p = not significant for BMI). The fasting glycemia was significantly higher in Trp19 carriers both before and after the intervention (p < 0.01). Further, plasma triglyceride levels decreased in Ser19Ser homozygotes but increased in Trp19 carriers (1.42 +/- 0.62 to 1.28 +/- 0.48 vs. 1.15 +/- 0.47 to 1.41 +/- 0.80 mmol/l; p < 0.05 for differences between the groups). Similarly, in carriers of at least 1 less common APOA5 allele (n = 26), plasma low-density lipoprotein cholesterol levels did not decrease as they did in T-1131T/Ser19Ser carriers (3.11 +/- 0.70 to 3.27 +/- 0.81 vs. 3.39 +/- 0.81 to 3.16 +/- 0.86 mmol/l; p < 0.05 for differences between the groups).

CONCLUSIONS

APOA5 gene variants have effects on the decrease in plasma triglyceride and low-density lipoprotein cholesterol level in females in a model combining their dietary habits and physical activity changes.

Replacement of dietary saturated FAs by PUFAs in diet and reverse cholesterol transport

Dietary intervention is the first and usually successful approach in the treatment of high LDL cholesterol (LDL-C) concentration, but it is frequently accompanied by a decrease in HDL concentration. We studied 14 male volunteers on two different diets, high saturated fatty acid (SFA) and high PUFA, in a crossover design to test whether a decrease in HDL can affect reverse cholesterol transport from relabeled macrophages. A significant decrease of LDL-C (in mmol/l) after a PUFA diet compared with an SFA diet from 3.15 +/- 0.65 to 2.80 +/- 0.56 (P < 0.01) was accompanied by a significant decrease of HDL cholesterol (HDL-C) (in mmol/l) from 1.21 +/- 0.30 to 1.10 +/- 0.32 (P < 0.05). These changes did not affect cholesterol efflux (CHE) from macrophages (9.74 +/- 1.46% vs. 9.53 +/- 1.41%). There was no correlation between individual changes of HDL-C and changes of CHE. It is concluded that the decrease of HDL-C after successful dietary intervention of LDL-C is not accompanied by a decrease of CHE.

Differences in expression of cholesterol 7alpha-hydroxylase between PHHC and Wistar rats

PHHC rats represent a suitable experimental model of polygenic hypercholesterolemia. It has been found that its metabolic defect is not related to alimentary cholesterol absorption and LDL clearance. We have tested possible changes in cholesterol clearance from the liver to bile acids by analysis of the expression of the cholesterol 7alpha-hydroxylase (cyp7A1) gene in PHHC (N = 20) and Wistar (controls) (N = 19) male rats. The animals were fed standard laboratory diet (CD) or control diet containing 5% fat and 2% cholesterol (HCD) for two weeks. SSCP and RT-PCR were used for mutation analysis and study of gene expression, respectively. Although the basal cholesterolemia in PHHC was similar to controls (1.80 +/- 0.48 and 1.52 +/- 0.39 mmol/l, respectively), it rose in rats fed on HCD to 9.81 +/- 1.65 mmol/l in PHHC rats and only to 2.19 +/- 0.41 mmol/l in controls. Similarly to the basal cholesterol concentration, the gene expression of cyp7A1 in the liver of rats on CD was the same in both compared groups on the control diet. In controls on HCD, cyp7A1 gene expression increased almost 4-fold immediately on the first day and achieved up to approximately 20-multiple basal expression in the end of the feeding period. Compared to the controls, after switching to HCD the cyp7A1 gene expression in PHHC rats did not change dramatically. These results suggest that the cyp7A1 gene plays an important role in development of hypercholesterolemia in PHHC rats.