Gene-environment interaction and the GNB3 gene in the Atherosclerosis Risk in Communities study

lncRNA expression profiles and associated ceRNA network analyses in epicardial adipose tissue of patients with coronary artery disease

Epicardial adipose tissue (EAT) contributes to the pathophysiological process of coronary artery disease (CAD). The expression profiles of long non-coding RNAs (lncRNA) in EAT of patients with CAD have not been well characterized. We conducted high-throughput RNA sequencing to analyze the expression profiles of lncRNA in EAT of patients with CAD compared to patients without CAD. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were executed to investigate the principal functions of the significantly dysregulated mRNAs. We confirmed a dysregulated intergenic lncRNA (lincRNA) (LINC00968) by real-time quantitative PCR (RT-qPCR). Subsequently, we constructed a ceRNA network associated with LINC00968, which included 49 mRNAs. Compared with the control group, lncRNAs and genes of EAT in CAD were characterized as metabolic active and pro-inflammatory profiles. The sequencing analysis detected 2539 known and 1719 novel lncRNAs. Then, we depicted both lncRNA and gene signatures of EAT in CAD, featuring dysregulation of genes involved in metabolism, nuclear receptor transcriptional activity, antigen presentation, chemokine signaling, and inflammation. Finally, we identified a ceRNA network as candidate modulator in EAT and its potential role in CAD. We showed the expression profiles of specific EAT lncRNA and mRNA in CAD, and a selected non-coding associated ceRNA regulatory network, which taken together, may contribute to a better understanding of CAD mechanism and provide potential therapeutic targets.Trial registration Chinese Clinical Trial Registry, No. ChiCTR1900024782.

Gene and environmental interactions according to the components of lifestyle modifications in hypertension guidelines

Risk factors for hypertension consist of lifestyle and genetic factors. Family history and twin studies have yielded heritability estimates of BP in the range of 34–67%. The most recent paper of BP GWAS has explained about 20% of the population variation of BP. An overestimation of heritability may have occurred in twin studies due to violations of shared environment assumptions, poor phenotyping practices in control cohorts, failure to account for epistasis, gene-gene and gene-environment interactions, and other non-genetic sources of phenotype modulation that are suspected to lead to underestimations of heritability in GWAS. The recommendations of hypertension guidelines in major countries consist of the following elements: weight reduction, a healthy diet, dietary sodium reduction, increasing physical activity, quitting smoking, and moderate alcohol consumption. The hypertension guidelines are mostly the same for each country or region, beyond race and culture. In this review, we summarize gene-environmental interactions associated with hypertension by describing lifestyle modifications according to the hypertension guidelines. In the era of precision medicine, clinicians who are responsible for hypertension management should consider the gene-environment interactions along with the appropriate lifestyle components toward the prevention and treatment of hypertension. We briefly reviewed the interaction of genetic and environmental factors along the constituent elements of hypertension guidelines, but a sufficient amount of evidence has not yet accumulated, and the results of genetic factors often differed in each study.

Aldehyde Dehydrogenases Genetic Polymorphism and Obesity: From Genomics to Behavior and Health

Obesity is multifactorial and complex. Remarkable progress has been made recently in search for polygenic obesity through genome-wide association study (GWAS), but biology of polygenic effects on obesity is largely poor. This review summarizes the available evidence and provides an overview of the links between ALDH2 variants and adiposity, which were firstly and mainly derived from studies of polygenic obesity and also indirectly investigated by using cell lines and mice. The genetic association studies have observed consistent associations of ALDH2 variants with obesity-related traits including BMI, waist circumference (WC), waist-to-hip ratio (WHR), and visceral fat accumulation. In consideration of ALDH2 variants with enzyme activity and alcohol consumption behavior in physiological mechanism studies, we proposed a model by which the physiological and behavioral consequences of alcohol consumption serve as an intermediary process between polymorphisms in ALDH2 and obesity.

Prediction of the Risk for Essential Hypertension among Carriers of C825T Genetic Polymorphism of G Protein β3 (GNB3) Gene

BACKGROUND

The guanine nucleotide-binding protein beta polypeptide 3 (GNB3) 825T allele encodes a product that enhances the activation of heterotrimeric G proteins, which is associated with the occurrence of the splice variant Gβ3 s that could play a role in vascular reactivity and hyperproliferation of smooth muscle cells, that makes such proteins attractive candidate gene products for susceptibility to essential hypertension (EH).

OBJECTIVE

To predict the risk for EH in individuals with C825T genetic polymorphism of G protein β3 gene.

METHODS

The study consisted of 222 normotensive individuals and 216 hypertensive patients. Individuals were genotyped for C825T genetic polymorphism of G protein β3 gene rs5443 by using restriction fragment length polymorphism.

RESULTS

Frequencies of C and T alleles were 58.1% and 41.9%, respectively, in the control group compared with 47.7% and 52.3%, respectively, in the hypertensive group. The carriers of rs5443 (T) allele exhibited a significant greater risk for EH compared with the carriers of rs5443 (C) allele (odds ratio = 1.5, 95% confidence interval = 1.2-2.0).

CONCLUSION

T allele is a risk factor for EH in the Egyptian population, which may be used as a prognostic and a therapeutic target of prophylaxis.

GNB3 and FTO Polymorphisms and Pregnancy Weight Gain in Black Women

BACKGROUND

Gestational weight gain (GWG) is a modifiable risk factor for obesity in women. Black women have the greatest prevalence of high body mass, which predisposes them to excessive GWG. Increased understanding of genetic influences on GWG has implications for the health of women. The purpose of this study was to explore the associations of GNB3 and FTO risk alleles in pregnant women with prepregnancy body mass index (BMI), GWG, and postpartum and infant birth weights.

RESEARCH DESIGN AND METHODS

This was an observational, prospective candidate gene association study. Pregnant, low-income Black women (N = 97) were enrolled in early pregnancy and followed until 6 months postpartum.

RESULTS

GWG differed depending on number of FTO risk alleles. The mean 6-month postpartum BMI differed, although not significantly, by 4 kg/m(2) between homozygous women. There was an interaction between the FTO risk allele and prepregnancy BMI (p = .022), with obese homozygote AA women having significantly higher mean GWG than obese TT women. When controlling for age and smoking, the FTO gene and physical activity predicted GWG (p = .032). Although not statistically significant, women who carried the GNB3 T risk allele gained 6 pounds more than noncarriers, and mean 6-month postpartum BMI differed by 2.2 kg/m(2) between homozygous women. Neither the GNB3 nor FTO gene predicted prepregnancy BMI, infant birth weight, or postpartum weight.

CONCLUSION

Obese women homozygous for the FTO risk allele were at greater risk of excessive GWG compared to nonrisk allele homozygous obese women or nonobese women. This study provides evidence of the FTO gene's effect on GWG in Black women.

Influence of obesity on association between genetic variants identified by genome-wide association studies and hypertension risk in Chinese children

BACKGROUND

Childhood hypertension is a complex disease influenced by both genetic and environmental factors. We aimed to examine how obesity status influences the association of 6 single nucleotide polymorphisms (SNPs) identified by genome-wide association studies (GWASs) with systolic/diastolic blood pressure (SBP/DBP) and hypertension in Chinese children.

METHODS

We recruited 619 hypertensive case subjects and 2,458 individuals with normal blood pressure from the Beijing Child and Adolescent Metabolic Syndrome study, a population-based case-control study. We selected 6 SNPs from earlier GWASs of hypertension and genotyped them using TaqMan assay.

RESULTS

In the normal weight group, we did not observe any significant association of 6 SNPs and the genetic risk score (GRS) with SBP/DBP and hypertension (all P > 0.05). Only STK39 rs3754777 was significantly associated with higher DBP (P = 0.02) in the overweight subjects. In the obese group, 3 SNPs and the GRS were significantly associated with higher SBP (ATP2B1 rs17249754: P = 0.02; CSK rs1378942: P = 0.003; CYP17A1 rs1004467: P = 0.04; GRS: P = 0.0002). We also observed a significant association of 4 SNPs and the GRS with hypertension (ATP2B1 rs17249754: P = 0.02; CSK rs1378942: P = 0.02; CYP17A1 rs1004467: P = 0.02; MTHFR rs1801133: P = 0.03; GRS: P = 0.0004). Correction for multiple testing had no influence on the statistical significance of the association of GRS with SBP/hypertension.

CONCLUSIONS

This study shows a significant association of hypertension susceptibility loci only in obese Chinese children, suggesting a likely influence of childhood obesity on the risk of hypertension.

Effects of aerobic exercise training on psychosocial status and serum uric Acid in men with essential hypertension: a randomized controlled trial

BACKGROUND

Chronic psychosocial stress and serum uric acid (SUA) level have been implicated in the etiology and cardiovascular events risk factors in hypertension. Studies have reported significant benefit of exercise in the overall management of hypertension. However, studies on the effect of exercise on psychosocial stress and SUA in the management of hypertension seem scanty.

AIM

The aim of this study was to determine the effect of continuous training program on SUA and psychosocial status of black African (Nigerian) population with hypertension.

SUBJECTS AND METHODS

Age-matched randomized controlled trial was used; subjects with diagnosis of hypertension attending the hypertensive clinic of Murtala Muhammed Specialist Hospital (MMSH), Kano, Nigeria form the population for the study. Two hundred and seventeen subjects with mild to moderate (systolic blood pressure (SBP) between 140 and180 and diastolic blood pressure (DBP) between 90 and 109 mmHg) essential hypertension were grouped into continuous (112) and control groups (105). The continuous group involved in an 8 weeks continuous training (60%-79% HR max) of between 45 and 60 min, 3 times per week, while the controls group remain sedentary. SBP, DBP, SUA, VO(2) max and psychosocial status were assessed. Student t-test and Pearson correlation test were used in data analysis.

RESULTS

The study revealed significant beneficial effect of continuous training programs on VO(2) max, SBP, DBP, SUA, and psychosocial status (P < 0.05). Psychosocial status and SUA was significantly and positively and negatively correlated respectively with VO(2) max at P < 0.01.

CONCLUSIONS

This study concludes and supports the recommendations of moderate intensity (continuous) training program in blood pressure reduction, SUA and psychosocial stress management in hypertension.

Genetic effects at pleiotropic loci are context-dependent with consequences for the maintenance of genetic variation in populations

Context-dependent genetic effects, including genotype-by-environment and genotype-by-sex interactions, are a potential mechanism by which genetic variation of complex traits is maintained in populations. Pleiotropic genetic effects are also thought to play an important role in evolution, reflecting functional and developmental relationships among traits. We examine context-dependent genetic effects at pleiotropic loci associated with normal variation in multiple metabolic syndrome (MetS) components (obesity, dyslipidemia, and diabetes-related traits). MetS prevalence is increasing in Western societies and, while environmental in origin, presents substantial variation in individual response. We identify 23 pleiotropic MetS quantitative trait loci (QTL) in an F₁₆ advanced intercross between the LG/J and SM/J inbred mouse strains (Wustl:LG,SM-G16; n = 1002). Half of each family was fed a high-fat diet and half fed a low-fat diet; and additive, dominance, and parent-of-origin imprinting genotypic effects were examined in animals partitioned into sex, diet, and sex-by-diet cohorts. We examine the context-dependency of the underlying additive, dominance, and imprinting genetic effects of the traits associated with these pleiotropic QTL. Further, we examine sequence polymorphisms (SNPs) between LG/J and SM/J as well as differential expression of positional candidate genes in these regions. We show that genetic associations are different in different sex, diet, and sex-by-diet settings. We also show that over- or underdominance and ecological cross-over interactions for single phenotypes may not be common, however multidimensional synthetic phenotypes at loci with pleiotropic effects can produce situations that favor the maintenance of genetic variation in populations. Our findings have important implications for evolution and the notion of personalized medicine.

We look at gene-by-diet and gene-by-sex interactions underlying natural variation in multiple metabolic traits mapping to the same regions of the genome in a mouse model. We find that the underlying genetic architecture of these traits is different in different sex and diet contexts. We further use expression data and whole-genome polymorphism data to identify compelling candidates for experimental follow-up. We use these results to examine theoretical evolutionary predictions about how variation in populations can be maintained. There has been much discussion of late on how to use evolutionary theory to inform medical genomics. Mouse models may be especially appropriate for bridging the divide between evolutionary and biomedical research, because they allow the study of the effects of natural alleles on normal variation and because human-mouse homology is well defined. Our study is unique in examining quantitative trait loci from both evolutionary and biomedical perspectives, and we highlight the complex connections of the traits comprising the metabolic syndrome and the evolutionary implications of their underlying genetic architecture. This is important for understanding disease etiology and is relevant to personalized medicine.

Do genetic variations alter the effects of exercise training on cardiovascular disease and can we identify the candidate variants now or in the future?

Cardiovascular disease (CVD) and CVD risk factors are highly heritable, and numerous lines of evidence indicate they have a strong genetic basis. While there is nothing known about the interactive effects of genetics and exercise training on CVD itself, there is at least some literature addressing their interactive effect on CVD risk factors. There is some evidence indicating that CVD risk factor responses to exercise training are also heritable and, thus, may have a genetic basis. While roughly 100 studies have reported significant effects of genetic variants on CVD risk factor responses to exercise training, no definitive conclusions can be generated at the present time, because of the lack of consistent and replicated results and the small sample sizes evident in most studies. There is some evidence supporting “possible” candidate genes that may affect these responses to exercise training: APO E and CETP for plasma lipoprotein-lipid profiles; eNOS, ACE, EDN1, and GNB3 for blood pressure; PPARG for type 2 diabetes phenotypes; and FTO and BAR genes for obesity-related phenotypes. However, while genotyping technologies and statistical methods are advancing rapidly, the primary limitation in this field is the need to generate what in terms of exercise intervention studies would be almost incomprehensible sample sizes. Most recent diabetes, obesity, and blood pressure genetic studies have utilized populations of 10,000–250,000 subjects, which result in the necessary statistical power to detect the magnitude of effects that would probably be expected for the impact of an individual gene on CVD risk factor responses to exercise training. Thus at this time it is difficult to see how this field will advance in the future to the point where robust, consistent, and replicated data are available to address these issues. However, the results of recent large-scale genomewide association studies for baseline CVD risk factors may drive future hypothesis-driven exercise training intervention studies in smaller populations addressing the impact of specific genetic variants on well-defined physiological phenotypes.

Interactions of genetic variants with physical activity are associated with blood pressure in Chinese: the GenSalt study

BACKGROUND

Blood pressure (BP) homeostasis involves complex interactions among genetic and nongenetic factors, providing major challenges to dissection of the genetic components that influence BP and hypertension. In this study, we examine the effects of interaction of genetic variants with physical activity on BP in a relatively genetically homogenous cohort of rural Chinese villagers.

METHODS

Generalized estimating equations analysis was used to test for associations of systolic blood pressure (SBP) and diastolic blood pressure (DBP) with variants in 24 genes in BP pathways (196 single-nucleotide polymorphisms (SNPs)) among 3,142 Chinese participants divided according to physical activity (active vs. inactive groups).

RESULTS

In the physically active group, two SNPs in NR3C2 were significantly associated with lower SBP, and a SNP in SCNN1B was significantly associated with lower SBP and DBP. In the physically inactive group, a SNP in APLNR was associated with lower SBP, a SNP in GNB3 (guanine nucleotide binding protein, β polypeptide 3) was associated with higher SBP and DBP, and a SNP in BDKRB2 (bradykinin receptor B2) was associated with lower DBP. Cumulative effects in carriers of minor alleles of these SNPs showed reductions of SBP and DBP as large as 8 and 5 mm Hg, respectively, in the active individuals compared to inactive individuals carrying the same number of minor alleles.

CONCLUSIONS

We found that physical activity modifies the effects of genetic variants on BP. However, our results also show that active individuals with specific genotypes always have lower BP than inactive individuals with the same genotypes, demonstrating the overall beneficial effects of physical activity on BP.

SNP-by-fitness and SNP-by-BMI interactions from seven candidate genes and incident hypertension after 20 years of follow-up: the CARDIA Fitness Study

The association of SNPs from seven candidate genes, including genotype-by-baseline fitness and genotype-by-baseline body mass index (BMI) interactions, with incident hypertension over 20 years was investigated in 2663 participants (1301 blacks, 1362 whites) of the Coronary Artery Risk Development in Young Adults Study (CARDIA) Study. Baseline cardiorespiratory fitness was determined from duration of a modified Balke treadmill test. A total of 98 SNPs in blacks and 89 SNPs in whites from seven candidate genes were genotyped. Participants that became hypertensive (295 blacks and 146 whites) had significantly higher blood pressure and BMI (both races), and lower fitness (blacks only) at baseline than those who remained normotensive. Markers at the PPARGC1A and BDKRB2 genes were nominally associated with greater risk of hypertension, while one marker each at the BDKRB2 and NOS3 genes were nominally associated with lower risk. The association of baseline fitness with risk of hypertension was nominally modified by genotype at markers within the ACE, AGT, BDKRB2, and NOS3 genes in blacks and the BDKRB2, EDN1, and PPARGC1A genes in whites. BDKRB2 rs4900318 showed nominal interactions with baseline fitness on the risk of hypertension in both races. The association of baseline BMI with risk of hypertension was nominally modified by GNB3 rs2301339 genotype in whites. None of the above associations were statistically significant after correcting for multiple testing. We found that SNPs in these candidate genes did not modify the association between baseline fitness or BMI and risk of hypertension in CARDIA participants.

Gene-environment interaction for hypertension among African American women across generations

African American women have the highest prevalence of hypertension and obesity of any group in the United States. African American girls have the highest incidence of obesity of any groups of children in the nation, and diagnoses of hypertension have been rising among this group. Because both genetic heredity and body mass index (BMI) are important risk factors for hypertension, this study examined the gene-BMI interaction for hypertension across the lifespan in two generations of African American women. Participants comprised of 868 African American women in the parent cohort and 322 in the offspring cohort from the Hypertension Genetic Epidemiology Network (HyperGEN) study, part of the Family Blood Pressure Program (FBPP). A total of 115 single-nucleotide polymorphisms (SNPs) were evaluated among the parent cohort and 491 among the offspring cohort for tests of SNP-BMI interaction using methods of false discovery rate (FDR; <.20) and examination of minor allele frequency (MAF; >.05) and Hardy-Weinberg equilibrium (>.10). One SNP (located in the CAPN 13 gene, rs1879282) passed adjustments for the multiple testing mentioned above and had a significant (p < .01) gene-BMI interaction on both systolic blood pressure (SBP) and diastolic blood pressure (DBP) among African American female offspring. The rs1879282 SNP is located on chromosome 2 on the calpain (CAPN) 13 gene, which is part of a family of cytosolic calcium-activated proteases involved in apoptosis, cell division, modulation of integrin-cytoskeletal interactions, and synaptic plasticity. This SNP was not available for testing in the African American parent cohort.

Genetic basis of inter-individual variability in the effects of exercise on the alleviation of lifestyle-related diseases

Habitual exercise training, including a high-intensity interval walking programme, improves cardiorespiratory fitness and alleviates lifestyle-related diseases, such as obesity, hypertension and dyslipidaemia. However, the extent of improvement has been shown to differ substantially among individuals for various exercise regimens. A body of literature has demonstrated that gene polymorphisms could account for the inter-individual variability in the improvement of risk factors for lifestyle-related diseases following exercise training. However, the fractions of the variability explained by the polymorphisms are small (5%). Also, it is likely that the effects of gene polymorphisms differ with exercise regimens and subject characteristics. These observations suggest the necessity for further studies to exhaustively identify such gene polymorphisms. More importantly, the physiological and molecular genetic mechanisms by which gene polymorphisms interact with exercise to influence the improvements of risk factors for lifestyle-related diseases differentially remain to be clarified. A better understanding of these issues should lead to more effective integration of exercise to optimize the treatment and management of individuals with lifestyle-related diseases.

The human gene map for performance and health-related fitness phenotypes: the 2006-2007 update

This update of the human gene map for physical performance and health-related fitness phenotypes covers the research advances reported in 2006 and 2007. The genes and markers with evidence of association or linkage with a performance or a fitness phenotype in sedentary or active people, in responses to acute exercise, or for training-induced adaptations are positioned on the map of all autosomes and sex chromosomes. Negative studies are reviewed, but a gene or a locus must be supported by at least one positive study before being inserted on the map. A brief discussion on the nature of the evidence and on what to look for in assessing human genetic studies of relevance to fitness and performance is offered in the introduction, followed by a review of all studies published in 2006 and 2007. The findings from these new studies are added to the appropriate tables that are designed to serve as the cumulative summary of all publications with positive genetic associations available to date for a given phenotype and study design. The fitness and performance map now includes 214 autosomal gene entries and quantitative trait loci plus seven others on the X chromosome. Moreover, there are 18 mitochondrial genes that have been shown to influence fitness and performance phenotypes. Thus,the map is growing in complexity. Although the map is exhaustive for currently published accounts of genes and exercise associations and linkages, there are undoubtedly many more gene-exercise interaction effects that have not even been considered thus far. Finally, it should be appreciated that most studies reported to date are based on small sample sizes and cannot therefore provide definitive evidence that DNA sequence variants in a given gene are reliably associated with human variation in fitness and performance traits.

Implications of gene-behavior interactions: prevention and intervention for obesity

A vast body of research exists to demonstrate that obesity is a complex disorder with a strong genetic basis and a multifactorial etiology. Yet despite the overwhelming evidence that genes play an important role in the development of obesity, many people argue that the increasing prevalence of obesity is simply due to an abundance of palatable food and a dearth of opportunities for physical exercise. While activity and eating behaviors contribute substantially to the development of obesity, considering these to be the only etiologic factors is directly contradictory to what is now known about how eating and energy balance are regulated. Our understanding of the molecular processes controlling eating behavior, in particular, has accelerated exponentially in the last 10 years, and this is one area in which obesity genetics has made great progress. Our challenge is to understand more fully how genetic variation may interact with behavioral factors to influence the regulation of body weight and adiposity. Although exercise and diet strategies are used routinely for obesity treatment, there is a huge variability in how individuals respond to these interventions. There is also a substantial amount of evidence that such responses may also be regulated by genes. Understanding gene-response relationships is the key to developing more efficacious intervention and prevention programs for obesity.

Implications of gene-behavior interactions: prevention and intervention for obesity

A vast body of research exists to demonstrate that obesity is a complex disorder with a strong genetic basis and a multifactorial etiology. Yet despite the overwhelming evidence that genes play an important role in the development of obesity, many people argue that the increasing prevalence of obesity is simply due to an abundance of palatable food and a dearth of opportunities for physical exercise. While activity and eating behaviors contribute substantially to the development of obesity, considering these to be the only etiologic factors is directly contradictory to what is now known about how eating and energy balance are regulated. Our understanding of the molecular processes controlling eating behavior, in particular, has accelerated exponentially in the last 10 years, and this is one area in which obesity genetics has made great progress. Our challenge is to understand more fully how genetic variation may interact with behavioral factors to influence the regulation of body weight and adiposity. Although exercise and diet strategies are used routinely for obesity treatment, there is a huge variability in how individuals respond to these interventions. There is also a substantial amount of evidence that such responses may also be regulated by genes. Understanding gene-response relationships is the key to developing more efficacious intervention and prevention programs for obesity.

Public health genomics: translating obesity genomics research into population health benefits

We examine how a public health genomics framework can be used to move genomic discoveries into clinical and public health practice for obesity prevention and treatment. There are four phases of translational research: T1: discovery to candidate health application; T2: health application to evidence-based practice guidelines; T3: practice guidelines to health practice; and T4: practice to population health impact. Types of multidisciplinary research and knowledge synthesis needed for each phase, as well as the importance of developing and disseminating evidence-based guidelines, are discussed. Because obesity genomics research is mostly in the discovery phase or in the very early phases of translation (T1), the authors present this framework to illustrate the range of translation activities needed to move genomic discoveries in obesity to actual applications that reduce the burden of obesity at the population level.

Genotype-phenotype associations: modulation by diet and obesity

Changes in diet are likely to reduce chronic disorders, but after decades of active research and heated discussion, the question still remains: what is the optimal diet to achieve this elusive goal? Is it a low-fat diet, as traditionally recommended by multiple medical societies? Or a high monounsaturated fat (MUFA) diet as predicated by the Mediterranean diet? Perhaps a high polyunsaturated fat (PUFA) diet based on the cholesterol-lowering effects? The right answer may be all of the above but not for everybody. A well-known phenomenon in nutrition research and practice is the dramatic variability in interindividual response to any type of dietary intervention. There are many other factors influencing response, and they include, among many others, age, sex, physical activity, alcohol, and smoking as well as genetic factors that will help to identify vulnerable populations/individuals that will benefit from a variety of more personalized and mechanistic-based dietary recommendations. This potential could and needs to be developed within the context of nutritional genomics that in conjunction with systems biology may provide the tools to achieve the holy grail of dietary prevention and therapy of chronic diseases and cancer. This approach will break with the traditional public health approach of "one size fits all." The current evidence based on nutrigenetics has begun to identify subgroups of individuals who benefit more from a low-fat diet, whereas others appear to benefit more from high MUFA or PUFA diets. The continuous progress in nutrigenomics will allow some time in the future to provide targeted gene-based dietary advice.

Interaction of G-protein beta3 subunit and nitric oxide synthase gene polymorphisms on carotid artery intima-media thickness in young adults: the Bogalusa Heart Study

BACKGROUND

G-protein beta3 subunit (GNB3) gene C825T and endothelial nitric oxide (eNOS) gene G894T polymorphisms both influence arterial structure and function. However, information is scant regarding the interaction of these genes on arterial wall thickness.

METHODS

This aspect was examined in 654 white and black subjects, aged 25-43 years (72.9% white, 39.3% male). Arterial wall thickness was assessed in terms of the average intima-media thickness (IMT) of common carotid, internal carotid, and carotid bulb segments by B-mode ultrasonography.

RESULTS

Frequencies of T allele of the GNB3 C825T polymorphism (0.718 vs. 0.304, P < 0.0001) and G allele of the eNOS G894T polymorphism (0.868 vs. 0.661, P < 0.0001) were higher in blacks compared to whites. In a multivariate model including gender, age, mean arterial pressure, body mass index, triglycerides/HDL cholesterol ratio, insulin resistance index, smoking, and/or race, there was no significant genotypic effect on carotid IMT with respect to GNB3 C825T or eNOS G894T polymorphisms among whites, blacks, and total sample. However, the carriers of TT genotype of the GNB3 C825T and T allele of the eNOS G894T had a significantly lower carotid IMT among blacks (P = 0.003) and the total sample (P = 0.006).

CONCLUSION

These results indicate that the genetic variations of the eNOS gene in combination with the GNB3 gene jointly influence carotid artery wall thickening process in young adults, especially in blacks.

Why study gene-environment interactions?

PURPOSE OF REVIEW

We examine the reasons for investigating gene-environment interactions and address recent reports evaluating interactions between genes and environmental modulators in relation to cardiovascular disease and its common risk factors.

RECENT FINDINGS

Studies focusing on smoking, physical activity, and alcohol and coffee consumption are observational and include relatively large sample sizes. They tend to examine single genes, however, and fail to address interactions with other genes and other correlated environmental factors. Studies examining gene-diet interactions include both observational and interventional designs. These studies are smaller, especially those including dietary interventions. Among the reported gene-diet interactions, it is important to highlight the strengthened position of APOA5 as a major gene that is involved in triglyceride metabolism and modulated by dietary factors, and the identification of APOA2 as a modulator of food intake and obesity risk.

SUMMARY

The study of gene-environment interactions is an active and much needed area of research. Although technical barriers of genetic studies are rapidly being overcome, inclusion of comprehensive and reliable environmental information represents a significant shortcoming of genetics studies. Progress in this area requires inclusion of larger populations but also more comprehensive, standardized, and precise approaches to capturing environmental information.