Is laboratory medicine ready for the era of personalized medicine? A survey addressed to laboratory directors of hospitals/academic schools of medicine in Europe.

Developments in "-omics" are creating a paradigm shift in laboratory medicine leading to personalized medicine. This allows the increase in diagnostics and therapeutics focused on individuals rather than populations. In order to investigate whether laboratory medicine is ready to play a key role in the integration of personalized medicine in routine health care and set the state-of-the-art knowledge about personalized medicine and laboratory medicine in Europe, a questionnaire was constructed under the auspices of the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) and the European Society of Pharmacogenomics and Personalised Therapy (ESPT). The answers of the participating laboratory medicine professionals indicate that they are aware that personalized medicine can represent a new and promising health model, and that laboratory medicine should play a key role in supporting the implementation of personalized medicine in the clinical setting. Participants think that the current organization of laboratory medicine needs additional/relevant implementations such as (i) new technological facilities in -omics; (ii) additional training for the current personnel focused on the new methodologies; (iii) incorporation in the laboratory of new competencies in data interpretation and counseling; and (iv) cooperation and collaboration among professionals of different disciplines to integrate information according to a personalized medicine approach.

Influence of inflammation on cardiovascular protective effects of cytochrome P450 epoxygenase-derived epoxyeicosatrienoic acids.

In addition to their role as xenobiotic metabolizing enzymes, cytochrome P450 (CYP) epoxygenases actively contribute to the metabolism of endogenous substances such as arachidonic acid. Epoxyeicosatrienoic acids (EETs) are epoxide derivative of arachidonic acid. CYP2C8/9 and CYP2J2 are the main epoxygenases expressed in human tissues including endothelial cells which are the chief sources of EET formation in human body. Once formed, EETs are primarily metabolized to their less biologically active metabolites, dihydroxyeicosatrienoic acids, by soluble epoxy hydrolase (sEH) enzyme. EETs possess a wide range of established protective effects on human cardiovascular system of which vasodilatory, angiogenic and anti-inflammatory actions have been more extensively described. On the other hand, inflammation has shown to decrease the expression and activity of CYP enzyme, including epoxygenases. Given the fact that CYP epoxygenase-derive EETs exhibit potent cardiovascular protective effects, including anti-inflammation, and that inflammation suppress CYP activation and EET formation, it would make sense to speculate that under inflammatory conditions there exists an inflammation-epoxygenase-EET-inflammation vicious cycle in which the inflammation-induced downregulation of CYP epoxygenases causes a decrease in the EET production. Insufficient EET synthesis would, in turn, lead to an ineffective EET-mediated anti-inflammatory effect, leading to an augmentation of systemic and regional inflammatory responses and further downregulation of CYP epoxygenase activity/EET production. This cycle, if any, might help to better understanding of pathophysiology of chronic cardiovascular diseases and also could be an emerging target for further pharmacological therapy of disorders in which increased inflammatory responses are known to occur.

A common variant highly associated with plasma VEGFA levels also contributes to the variation of both LDL-C and HDL-C.

Vascular endothelial growth factor A (VEGFA) is among the most-significant stimulators of angiogenesis. Its effect on cardiovascular diseases and on the variation of related risk factors such as lipid parameters is considered important, although as yet unclear. Recently, we identified four common variants (rs6921438, rs4416670, rs6993770, and rs10738760) that explain up to 50% of the heritability of plasma VEGFA levels. In the present study, we aimed at assessing the contribution of these variants to the variation of blood lipid levels (including apoE, triglycerides, total cholesterol, low- and high-density lipoprotein cholesterol levels (LDL-C and HDL-C)] in healthy subjects. The effect of these single-nucleotide polymorphisms (SNPs) on lipid levels was assessed using linear regression in discovery and replication samples (n = 1,006 and n = 1,145; respectively), followed by a meta-analysis. Their gene×gene and gene×environment interactions were also assessed. SNP rs6921438 was associated with HDL-C (ß = -0.08 mmol/l, P(overall) = 1.2 × 10(-7)) and LDL-C (ß = 0.13 mmol/l, P(overall) = 1.5 × 10(-4)). We also identified a significant association between the interaction rs4416670×hypertension and apoE variation (P(overall) = 1.7 × 10(-5)). Therefore, our present study shows a common genetic regulation between VEGFA and cholesterol homeostasis molecules. The SNP rs6921438 is in linkage disequilibrium with variants located in an enhancer- and promoter-associated histone mark region and could have a regulatory effect in the expression of surrounding genes, including VEGFA.

Epistatic study reveals two genetic interactions in blood pressure regulation.

BACKGROUND: Although numerous candidate gene and genome-wide association studies have been performed on blood pressure, a small number of regulating genetic variants having a limited effect have been identified. This phenomenon can partially be explained by possible gene-gene/epistasis interactions that were little investigated so far. METHODS: We performed a pre-planned two-phase investigation: in phase 1, one hundred single nucleotide polymorphisms (SNPs) in 65 candidate genes were genotyped in 1,912 French unrelated adults in order to study their two-locus combined effects on blood pressure (BP) levels. In phase 2, the significant epistatic interactions observed in phase 1 were tested in an independent population gathering 1,755 unrelated European adults. RESULTS: Among the 9 genetic variants significantly associated with systolic and diastolic BP in phase 1, some may act through altering the corresponding protein levels: SNPs rs5742910 (Padjusted≤0.03) and rs6046 (Padjusted =0.044) in F7 and rs1800469 (Padjusted ≤0.036) in TGFB1; whereas some may be functional through altering the corresponding protein structure: rs1800590 (Padjusted =0.028, SE=0.088) in LPL and rs2228570 (Padjusted ≤9.48×10-4) in VDR. The two epistatic interactions found for systolic and diastolic BP in the discovery phase: VCAM1 (rs1041163) * APOB (rs1367117), and SCGB1A1 (rs3741240) * LPL (rs1800590), were tested in the replication population and we observed significant interactions on DBP. In silico analyses yielded putative functional properties of the SNPs involved in these epistatic interactions trough the alteration of corresponding protein structures. CONCLUSIONS: These findings support the hypothesis that different pathways and then different genes may act synergistically in order to modify BP. This could highlight novel pathophysiologic mechanisms underlying hypertension.

Identification of cis- and trans-acting genetic variants explaining up to half the variation in circulating vascular endothelial growth factor levels.

RATIONALE: Vascular endothelial growth factor (VEGF) affects angiogenesis, atherosclerosis, and cancer. Although the heritability of circulating VEGF levels is high, little is known about its genetic underpinnings. OBJECTIVE: Our aim was to identify genetic variants associated with circulating VEGF levels, using an unbiased genome-wide approach, and to explore their functional significance with gene expression and pathway analysis. METHODS AND RESULTS: We undertook a genome-wide association study of serum VEGF levels in 3527 participants of the Framingham Heart Study, with preplanned replication in 1727 participants from 2 independent samples, the STANISLAS Family Study and the Prospective Investigation of the Vasculature in Uppsala Seniors study. One hundred forty single nucleotide polymorphism (SNPs) reached genome-wide significance (P<5×10(-8)). We found evidence of replication for the most significant associations in both replication datasets. In a conditional genome-wide association study, 4 SNPs mapping to 3 chromosomal regions were independently associated with circulating VEGF levels: rs6921438 and rs4416670 (6p21.1, P=6.11×10(-506) and P=1.47×10(-12)), rs6993770 (8q23.1, P=2.50×10(-16)), and rs10738760 (9p24.2, P=1.96×10(-34)). A genetic score including these 4 SNPs explained 48% of the heritability of serum VEGF levels. Six of the SNPs that reached genome-wide significance in the genome-wide association study were significantly associated with VEGF messenger RNA levels in peripheral blood mononuclear cells. Ingenuity pathway analyses showed found plausible biological links between VEGF and 2 novel genes in these loci (ZFPM2 and VLDLR). CONCLUSIONS: Genetic variants explaining up to half the heritability of serum VEGF levels were identified. These new insights provide important clues to the pathways regulating circulating VEGF levels.

The theory of reference values: an unfinished symphony.

The history of the theory of reference values can be written as an unfinished symphony. The first movement, allegro con fuoco, played from 1960 to 1980: a mix of themes devoted to the study of biological variability (intra-, inter-individual, short- and long-term), preanalytical conditions, standardization of analytical methods, quality control, statistical tools for deriving reference limits, all of them complex variations developed on a central melody: the new concept of reference values that would replace the notion of normality whose definition was unclear. Additional contributions (multivariate reference values, use of reference limits from broad sets of patient data, drug interferences) conclude the movement on the variability of laboratory tests. The second movement, adagio, from 1980 to 2000, slowly develops and implements initial works. International and national recommendations were published by the IFCC-LM (International Federation of Clinical Chemistry and Laboratory Medicine) and scientific societies [French (SFBC), Spanish (SEQC), Scandinavian societies…]. Reference values are now topics of many textbooks and of several congresses, workshops, and round tables that are organized all over the world. Nowadays, reference values are part of current practice in all clinical laboratories, but not without difficulties, particularly for some laboratories to produce their own reference values and the unsuitability of the concept with respect to new technologies such as HPLC, GCMS, and PCR assays. Clinicians through consensus groups and practice guidelines have introduced their own tools, the decision limits, likelihood ratios and Reference Change Value (RCV), creating confusion among laboratorians and clinicians in substituting reference values and decision limits in laboratory reports. The rapid development of personalized medicine will eventually call for the use of individual reference values. The beginning of the second millennium is played allegro ma non-troppo from 2000 to 2012: the theory of reference values is back into fashion. The need to revise the concept is emerging. The manufacturers make a friendly pressure to facilitate the integration of Reference Intervals (RIs) in their technical documentation. Laboratorians are anxiously awaiting the solutions for what to do. The IFCC-LM creates Reference Intervals and Decision Limits Committee (C-RIDL) in 2005. Simultaneously, a joint working group IFCC-CLSI is created on the same topic. In 2008 the initial recommendations of IFCC-LM are revised and new guidelines are published by the Clinical and Laboratory Standards Institute (CLSI C28-A3). Fundamentals of the theory of reference values are not changed, but new avenues are explored: RIs transference, multicenter reference intervals, and a robust method for deriving RIs from small number of subjects. Concomitantly, other statistical methods are published such as bootstraps calculation and partitioning procedures. An alternative to recruiting healthy subjects proposes the use of biobanks conditional to the availability of controlled preanalytical conditions and of bioclinical data. The scope is also widening to include veterinary biology! During the early 2000s, several groups proposed the concept of 'Universal RIs' or 'Global RIs'. Still controversial, their applications await further investigations. The fourth movement, finale: beyond the methodological issues (statistical and analytical essentially), important questions remain unanswered. Do RIs intervene appropriately in medical decision-making? Are RIs really useful to the clinicians? Are evidence-based decision limits more appropriate? It should be appreciated that many laboratory tests represent a continuum that weakens the relevance of RIs. In addition, the boundaries between healthy and pathological states are shady areas influenced by many biological factors. In such a case the use of a single threshold is questionable. Wherever it will apply, individual reference values and reference change values have their place. A variation on an old theme! It is strange that in the period of personalized medicine (that is more stratified medicine), the concept of reference values which is based on stratification of homogeneous subgroups of healthy people could not be discussed and developed in conjunction with the stratification of sick patients. That is our message for the celebration of the 50th anniversary of Clinical Chemistry and Laboratory Medicine. Prospects are broad, enthusiasm is not lacking: much remains to be done, good luck for the new generations!

Influence of genetic variations on levels of inflammatory markers of healthy subjects at baseline and one week after clopidogrel therapy; results of a preliminary study.

We aimed to assess the association between the most common polymorphisms of cytochrome P450 (CYP) epoxygenases on the plasma levels of inflammatory markers in a population of healthy subjects. We also sought to determine whether CYP2C19 2 polymorphism is associated with the anti-inflammatory response to clopidogrel. In a population of 49 healthy young males, the baseline plasma levels of inflammatory markers including C-reactive protein, haptoglobin, orosomucoid acid, CD-40 were compared in carriers vs. non-carriers of the most frequent CYP epoxygenase polymorphisms: CYP2C9 2, CYP2C9 3, CYP2C19 2, CYP2C8 2 and CYP2J2 7. Also, the variation of inflammatory markers from baseline to 7 days after administration of 75 mg per day of clopidogrel were compared in carriers vs. non-carriers of CYP2C19 allele and also in responders vs. hypo-responders to clopidogrel, determined by platelet reactivity tests. There was no significant association between epoxygenase polymorphisms and the baseline levels of inflammatory markers. Likewise, CYP2C19 allele was not associated with anti-inflammatory response to clopidogrel. Our findings did not support the notion that the genetic variations of CYP epoxygenases are associated with the level of inflammatory markers. Moreover, our results did not support the hypothesis that CYP2C19 2 polymorphism is associated with the variability in response to the anti-inflammatory properties of clopidogrel.

Biological and genetic factors associated with ABCB1 and pregnane-X-receptor expressions in peripheral blood mononuclear cells in the STANISLAS cohort.

BACKGROUND: ABCB1 is a membrane transporter ubiquitously expressed particularly in peripheral blood mononuclear cells (PBMCs). Resistance to drugs is associated with genetic variations of its gene and with modulation of its expression through the pregnane-X-receptor (PXR) transcription factor. We have previously shown that ABCB1 polymorphisms were associated with blood lipid concentrations. METHODS: We wanted to investigate the variation factors and the genetic determinants of ABCB1 and PXR expressions in PBMCs, and their interrelationships with plasma lipid levels. ABCB1 and PXR mRNA were quantified by real-time quantitative RT-PCR in PBMCs of 42 men and 39 women. RESULTS: ABCB1 and PXR were both expressed in PBMCs of all individuals, but their expressions were not significantly correlated. ABCB1 mRNA was correlated with body mass index (BMI; p=0.01) and age (p=0.03). In women, lymphocyte count also correlated with ABCB1 transcripts (p<0.01). After adjustment for BMI, correlation with age disappears. PXR mRNA expression depends on gender with men expressing higher PXR levels (p=0.01). PXR expression also correlates with γ-glutamyltransferase (GGT; p=0.02), but this disappeared after adjustment. CONCLUSIONS: Neither ABCB1 nor PXR expressions correlate with ABCB1 gene variants. Finally, association between ABCB1 or PXR expression in PBMCs and lipid or apolipoprotein plasma concentrations were not significant in this subset of healthy subjects. These results should be confirmed in a larger population sample and extended to patients with various cardiovascular risk profiles.

Expression of inflammatory molecules and associations with BMI in children.

BACKGROUND: Adipose tissue secrets several adipokines that have been proposed to be enrolled in many inflammatory pathways. Our aim was to investigate the adipokine expression in adipose tissue and peripheral blood mononuclear cells (PBMCs) in children. MATERIALS AND METHODS: Thirty-one (17 males and 14 females) healthy children aged 10.9 +/- 1.8 years with a body mass index (BMI) of 19.3 +/- 3.5 kg m(-2) were enrolled. Adipokines (TNF-alpha, IL-6 and leptin) gene expression was quantified by real-time quantitative PCR in adipose tissue and PBMCs from the same children. Their serum levels were also measured. RESULTS: BMI was positively correlated with leptin gene expression in adipose tissue and with leptin serum levels (beta = 0.476, P = 0.006 and beta = 0.576, P = 0.003 respectively). Leptin's serum levels were positively correlated with leptin gene expression in adipose tissue (beta = 0.462, P = 0.02). Adipose tissue gene expression of leptin and TNF-alpha and serum leptin and TNF-alpha serum levels were positively correlated (beta = 0.752, P < 0.001, beta = 0.311 and P = 0.015 respectively). In PBMCs, a positive correlation between TNF-alpha and IL-6 expression was found (beta = 0.526, P = 0.042). CONCLUSION: We demonstrated powerful correlations of adipokines gene expression in adipose tissue and PBMCs in children, underlying that these molecules share common pathways related to childhood obesity.

Drug metabolizing enzymes and transporters mRNA in peripheral blood mononuclear cells of healthy subjects: biological variations and importance of pre-analytical steps.

Quantification in peripheral blood mononuclear cells of mRNA of drug metabolizing enzymes or drug targets could give interesting, new information in the field of pharmacogenomics and molecular mechanisms. However, for the interpretation of these data, it is necessary to know mRNA biological variations. In this review, we propose a strategy based on the production and interpretation of clinical chemistry reference values. We discuss the concept of reference values; the necessity to master pre-analytical variations of CYP and ABC transporters; the choice of the analytical methods and of the reference genes; and finally the biological variations themselves. In particular, we focus on the importance of considering homogeneity for age, sex, degree of adiposity, tobacco and alcohol intake, food habits, and drug consumption, including their inductive effects, at the phase of subject recruitment. All this information is useful to define the partition and exclusion factors to obtain mRNA reference limits.

Capillary isotachophoresis study of lipoprotein network sensitive to apolipoprotein E phenotype. 1. ApoE distribution between lipoproteins.

Sixteen patients differing widely in plasma triglyceride content were divided into three groups by their apolipoprotein E (apoE) phenotype-E33 homozygotes, E23, and E34 heterozygotes. The plasma lipid and apoE distribution between individual lipoproteins was followed by capillary isotachophoresis (CITP) of plasma samples pre-stained with lipid fluorescent probe NBD-C6-ceramide and by fluorescein-labeled apoE, respectively. Among 12 peaks visualized by ceramide staining, an individual peak with very low density lipoproteins (VLDL) was identified. The VLDL cholesterol and apoE content determined by CITP directly in whole plasma were significantly related to their content as determined by conventional analysis with isolated VLDL. The ceramide distribution among lipoprotein pools was insensitive to apoE phenotype (49-53 : 7-11 : 39-43% for HDL, VLDL, and IDL/LDL, respectively) while the preferential binding of apoE to VLDL was observed in E34 patients compared to E33 (62 : 19 : 20 vs. 70 : 9 : 22%). In a study of apoE/F displacement from lipoproteins at plasma titration by apoC-III in vitro, apoE was found to bind more tightly to VLDL from E34 compared to E33 patients as evidenced by both the increased non-displaceable apoE pool, the increased VLDL sorbtion capacity for apoE, and the decreased displacement parameter in a "container" model of lipoprotein binding. Two different types of apoE package in a whole lipoprotein profile were observed. ApoE structure in a particular lipoprotein may underlie the phenotype-sensitive apoE distribution and apoC-III interference in hypertriglyceridemia.

Capillary isotachophoresis study of lipoprotein network sensitive to apolipoprotein E phenotype. 2. ApoE and apoC-III relations in triglyceride clearance.

The plasma (P), VLDL (V) triglyceride and apoB (B) clearance rates were measured both as 'mass' clearance (k (1)) and 'within the particle' clearance in three patient groups (E33, E23 and E34 phenotypes) at heparin-induced lipolysis in vivo. The lipid (C)- and apoE (E)-specific lipoprotein profiles both before and after heparin were followed by capillary isotachophoresis. The displacement of apoE by exogenous apoC-III at plasma titration in vitro was measured as well. The phenotype-sensitive lipoprotein networks were constructed based on an established set of metabolic rules. The k (1)(V) values did not differ between the three groups, but the lower k (1)(P) values showed significant differences. The k (1)(P) values for E33 and E23 groups were twofold higher compared to E34. A twofold increase in the rate constant for VLDL triglyceride clearance within the particle in E34 group compared to E23 reflected the inhibition of lipolysis by apoE2. For E33 group, (i) the k (1)(V) value was negatively correlated to the size of non-displaceable apoE pool in 2E lipoprotein and to the maximal apoE sorbtion capacity for 2E and 3E lipoproteins; (ii) the k (1)(P) value was not associated to the apoE binding parameters; (iii) the k (1)(V) value was positively correlated to the 4C level and the magnitude of apoC-III removal from VLDL particle; (iv) the k (1)(P) value was positively correlated to the content of apoE, while negatively with apoC-III, in VLDL remnants. For E34 group, the k (1)(V) value was positively correlated to 11C and 1-7C pool levels. Lipolysis- and receptor-mediated TG runways seem to be mostly balanced in E33 group, and VLDL TG clearance may be controlled by HDL through apoE dissociation from VLDLs and apolipoprotein accumulation within 'fast' HDLs at lipolysis.

Genetic profiling of human cell lines used as in vitro model to study cardiovascular pathophysiology and pharmacotoxicology.

BACKGROUND: Cell lines are widely used to monitor drug pharmacokinetics and pharmacodynamics and to investigate a number of biochemical mechanisms. However, little is known about the genetic profile of these in vitro models. OBJECTIVES: To analyze genetic profile of Thp1, U937, HL60, K562, HepG2, Kyn2, and Caco2 human cell lines with a focus on genetic variations within genes involved in the development of cardiovascular pathologies and drug treatment response. METHODS: Multiplex polymerase chain reaction (PCR), PCR-restriction fragment length polymorphism and TaqMan assays were used to genotype 120 polymorphisms within 68 genes previously shown to be involved in various processes such as inflammation, lipid metabolism, and blood pressure. RESULTS: We provide here a list of potential polymorphisms known to be associated with cardiovascular disease. Our results show that the seven cell lines examined carry several of these mutations within genes of interest. Due to the abundance of these variations, only two examples will be given in this abstract. For instance, U937 cells are homozygous for APOE varepsilon4, a mutant associated with higher susceptibility to cardiovascular diseases and lower response to statins. Our study also showed that deletion in intron 16 of the ACE gene, which is associated with susceptibility to hypertension and variation of response to ACE inhibitors, can be found in all considered cells but Kyn2 cells. CONCLUSION: We provide here a data bank of different cell lines genetic profile. In our opinion, this useful information may bring insights into the design and choice of an adequate in vitro model and may help to explain mysterious discrepancies in data from different laboratories.

Transcription factor and drug-metabolizing enzyme gene expression in lymphocytes from healthy human subjects.

We aimed to measure simultaneously the expression of drug-metabolizing enzymes (DME) and transcription factors (TF) with high importance in cardiovascular physiopathology in lymphocytes from healthy subjects. RNA was isolated from peripheral blood mononuclear cells (PBMC) of 20 subjects from the Stanislas Cohort. We used a microarray approach to measure 16 DME and 13 TF. Cytochromes P450 (P450s), including CYP2C19, CYP2C9, CYP2J2, CYP2D6, CYP1A1, CYP4F2, CYP4A11, CYP2E1, CYP11B2, CYP2C18, and CYP2A6, were expressed in all the subjects. CYP3A4 and CYP3A5 were not expressed. Glutathione S-transferases (GST) were expressed, but GSTM1 was seen only in some subjects. Pregnane X receptor (PXR), myocyte enhancer factor 2, vitamin D receptor, liver X receptor (LXR)-alpha, aryl hydrocarbon receptor (AHR), T-cell factor 7, constitutive androstane receptor, and aryl hydrocarbon receptor nuclear translocator (ARNT) were expressed in the majority of the subjects. Glucocorticoid receptor, peroxisome proliferator-activated receptor (PPAR)-gamma, and LXRbeta were expressed only in some individuals. PPARalpha mRNA was found in one subject only, and farnesoid X-activated receptor was not expressed. In addition, we found significant correlations between the expression of AHR, ARNT, and CYP1A1 and between PXR and P450 involved in leukotriene metabolism (CYP2C, CYP4F2, CYP4A11, CYP2J2, and CYP11B2). We describe here for the first time the presence of the majority of TF and DME in PBMC of healthy subjects without previous induction. The expression of these genes in lymphocytes could be a useful tool for further studying the physiological and pathological variations of DME and TF related to environment, to drug intake, and to cardiovascular metabolic cycles.

Statins as effectors of key activities involved in apoE-dependent VLDL metabolism: review and hypothesis.

Statins influence the major reactions of TG and HDL metabolism controlled, in part, by apoE level and its isoforms on the transcriptional, translational and post-translational levels. The existing unexplained maximal and minimal lipid responses (lowering TG and rising HDL-C) for varepsilon2 and varepsilon4 APOE alleles, respectively, following statin therapy may be completely described by the minimal set of the effects that follow: (i) the lowest and the highest efficiency of the binding of apoE2 and apoE4, respectively, to the LDL receptor; (ii) the increased competition of apoE4-containing VLDL with LDL for the LDL receptor; (iii) the isoform-independent induction by statin of the LDL receptor expression; (iv) the highest inhibition of hepatic lipase and the highest activation of lipoprotein lipase-directed lipolytic pathways for varepsilon2-bearing patients by statins; and (v) the increased clearance of large apoE-containing HDL, specifically with apoE4, at highest statin doses. These effects may be modulated additionally by apoE-controlled TG secretion. The molecular targets demonstrating an isoform-dependent sensitivity to statin therapy are outlined.

Analysis of the effect of multiple genetic variants of cardiovascular disease risk on insulin concentration variability in healthy adults of the STANISLAS cohort. The role of FGB-455 G/A polymorphism.

INTRODUCTION: Given the hypothesis of a common soil for atherosclerosis, type 2 diabetes and metabolic syndrome, we tested the contribution of gene polymorphisms involved in cardiovascular diseases on fasting insulin concentration (FIC). METHODS: The polymorphisms were investigated by a multiplex assay in 308 apparently healthy French middle-aged men and women, taken from the STANISLAS cohort. FIC was measured by a microparticular enzymatic immunoassay. RESULTS: After a series of regression analyses involving 34 polymorphisms, FGB -455G/A was the only polymorphism that remained significantly associated with FIC when adjusting the analyses for multiple testing. Stepwise models showed that FGB polymorphism accounted for 4.39% of FIC variability in men. Additionally, interactions between FGB and with environmental factors (alcohol and smoking in men, and BMI in women) were found. DISCUSSION: To our knowledge, this is the first study reporting an influence of FGB polymorphism on FIC in a healthy population. Our results concord with the already shown link between fibrinogen concentration and FIC, and support the hypothesis of a relationship between fibrinogen and endothelium in FIC homeostasis whose alteration may induce several metabolic disorders. The contribution of this gene, although modest, is consistent with the polygenic nature of insulin levels.

The lipoprotein lipase serine 447 stop polymorphism is associated with altered serum carotenoid concentrations in the Stanislas Family Study.

BACKGROUND: Carotenoids are mainly carried by lipoproteins in blood, however little is known about the influence of polymorphisms of apolipoproteins (apo), cholesterol ester transfer protein (CETP) and lipoprotein lipase (LPL) involved in serum lipid metabolism. OBJECTIVE: We aimed to analyze whether serum concentrations of 5 carotenoids (lutein-zeaxanthin, beta-cryptoxanthin, lycopene, alpha-carotene, beta-carotene) are associated with common polymorphisms of Apo E, Apo B, Apo CIII, CETP, and LPL. METHODS: Serum concentrations of lutein-zeaxanthin, beta-cryptoxanthin, lycopene, alpha-carotene, and beta-carotene were measured and polymorphisms of Apo E (cys112arg and arg158cys), Apo B (thr71ile), Apo CIII [C(-482)T, Apo CIII T(-455)C, Apo CIII C1100T, Apo CIII C3175G, Apo CIII T3206G], CETP (ile405val), and LPL (S447X) were determined in a sample of 447 children and adults drawn from the Stanislas Study. RESULTS: After adjustment for age, sex, smoking, physical activity, oral contraceptive use, BMI, serum cholesterol and triglyceride concentrations, and fruit and vegetable intakes, carriers vs. non carriers of the lipoprotein lipase X447 allele had significant lower concentrations of lutein-zeaxanthin, beta-cryptoxanthin, alpha-carotene and beta-carotene; differences vs. S447S genotype being the largest for X447X: -18.8%, -50.5%, -54.8% and -47.1%, for the four carotenoid fractions, respectively. No significant association was noticed for lycopene concentration. None of the other tested polymorphisms was significantly related to the serum carotenoid concentrations. CONCLUSIONS: Our investigation for the first time demonstrates that LPL S447X polymorphism could alter serum concentrations of carotenoids in healthy individuals, independently of serum cholesterol and triglyceride concentration. These data indicate that genetic factors could be involved in the variability of carotenoid bioavailability and bioconversion.

Enzymes and pharmacogenetics of cardiovascular drugs.

To select the best drug for a patient, physicians can use pharmacogenomics to optimize the effective drug and to minimize adverse reactions. Many enzymes are involved in the pharmacokinetic and pharmacodynamic sources of cardiovascular drugs. Taking the antihypertensive drugs as an example, the variability in blood pressure response is very high in different individuals, some of them having an increase in blood pressure. The most important proteins involved in the patient response to a drug are cytochrome P450 (CYP) 2D6, CYP2C19, CYP3A4 and the ABCB1 transporter. These enzymes, at the origin of important side effects or drug interactions, are responsible, at a great extent, of the cardiovascular drug response variability. Genotyping of the most important CYP today is easy while no reliable tool has been developed for the ABC transporters ATPase dependent and linked to the other phase I and phase II enzymes. The second relevant group of enzymes are involved in pharmacodynamic action of cardiovascular drugs: enzymes of the renin-angiotensin system and enzymes of the lipid metabolism. Angiotensin converting enzyme (ACE) is the most studied target with a relevant insertion deletion polymorphism. Contradictory reported data could be explained by ethnic differences or patient sample size which are often too small.