Association between Ala54Thr substitution of the fatty acid-binding protein 2 gene with insulin resistance and intra-abdominal fat thickness in Japanese men

Sex-specific association of FABP2 polymorphisms with the risk of obesity in the Tehran Cardio-Metabolic Genetic Study (TCGS)

FABP2 is one of the key genes involved in obesity development across different populations. However, there is no comprehensive report about the FABP2 contribution to obesity incidence among Iranians. Hence, the present study was designed to assess the probable role of FABP2 polymorphisms in obesity incidence in the Tehran Cardio- metabolic Genetic Study (TCGS) representative Iran population. Unrelated adults who had BMI information for at least 3 consecutive phases of the TCGS cohort were included. The control and case groups were defined as individuals who always had long-term persistent normal weight (20 < BMI < 25; n = 1526) and individuals who were long-term persistent obese (30 < BMI < 35; n = 1313), respectively. The logistic regression test was used to assess the possible association between SNPs located in and around the FABP2 gene with obesity. Also, we used Haploview and SHEsis to perform haplotype analysis to detect whether or not this chromosomal region is correlated with obesity. We found a gender-dependent association between the rs10857064 FABP2 and the risk of obesity. The presence of the rs10857064-G allele could significantly increase the risk of obesity only in women, not men (OR = 1.26; 95 % CI: 1.02-1.57; p = 0.03). Through haplotype analysis, we also detected that the TG haplotype containing rs7670862 and rs10857064 could significantly enhance the risk of obesity in women, further supporting the central role of rs10857064 in women's long-term obesity risk. In the current study, we revealed that rs10857064-G FABP2 can significantly predispose women to develop obesity. It highlights the importance of different genetic variants in both genders, which could help us to distinguish more efficient obesity screening tests and treatments based on gender in the future.

Effects of FABP2 Ala54Thr gene polymorphism on obesity and metabolic syndrome in middle-aged Korean women with abdominal obesity

OBJECTIVES

Asians (including Chinese, Japanese and Koreans), who generally have a relatively smaller body size and a lower mean body mass index (BMI), have a relatively higher risk of developing android-type obesity than westerners. Substitution of alanine for threonine (Ala54Thr) on the FABP2 gene (rs 1799883) is related to insulin resistance and obesity. However, few studies have examined this substitution in Koreans, and the number of Korean subjects in those studies is limited. For this reason, we investigated the differences between the FABP2 Ala54Thr polymorphism and obesity, hemodynamic variables, blood lipid profile results, and insulin resistance among middle-aged Korean women with abdominal obesity.

METHODS

We studied 243 middle-aged community-dwelling Korean women with abdominal obesity from Gyeonggi Province, Republic of Korea, who had no history of taking chronic medications. We examined each subject (n = 243) for the presence of FABP2 Ala54Thr polymorphism using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Subjects were also examined for obesity hemodynamic variables (n = 243), lipid profiles (n = 142), and insulin resistance (n = 142).

RESULTS

Of the 243 subjects, 117 had AA ("normal") homozygotic genotype, 100 had AT heterozygotic genotype, and 26 had TT homozygotic genotype for the FABP2 Ala54Thr polymorphism. The AT heterozygotic individuals had a significantly higher mean waist-to-hip ratio, abdominal fat area, and visceral fat area than individuals with other genotypes. TT homozygotic individuals had higher mean triglyceride and fasting glucose levels than individuals with other genotypes.

CONCLUSIONS

The results of this study show that the FABP2 Ala54Thr polymorphism was associated with central obesity and obesity-related metabolic syndrome among middle-aged Korean women.

Genes and Dietary Fatty Acids in Regulation of Fatty Acid Composition of Plasma and Erythrocyte Membranes

The fatty acid compositions of plasma lipids and cell membranes of certain tissues are modified by dietary fatty acid composition. Furthermore, many other factors (age, sex, ethnicity, health status, genes, and gene × diet interactions) affect the fatty acid composition of cell membranes or plasma lipid compartments. Therefore, it is of great importance to understand the complexity of mechanisms that may modify fatty acid compositions of plasma or tissues. We carried out an extensive literature survey of gene × diet interaction in the regulation of fatty acid compositions. Most of the related studies have been observational studies, but there are also a few intervention trials that tend to confirm that true interactions exist. Most of the studies deal with the desaturase enzyme cluster (FADS1, FADS2) in chromosome 11 and elongase enzymes. We expect that new genetic variants are being found that are linked with the genetic regulation of plasma or tissue fatty acid composition. This information is of great help to understanding the contribution of dietary fatty acids and their endogenic metabolism to the development of some chronic diseases.

Association between ACE (rs4646994), FABP2 (rs1799883), MTHFR (rs1801133), FTO (rs9939609) Genes Polymorphism and Type 2 Diabetes with Dyslipidemia

Diabetic dyslipidemia is one of the leading causes of coronary artery disease (CAD) death. Genetic and environmental factors play an important role in the development of type 2 diabetes mellitus (T2DM) and dyslipidemia. The present study was aimed to investigate the association of ACE (rs4646994), FABP2 (rs1799883), MTHFR (rs1801133) and FTO (rs9939609) genes polymorphism in T2DM with dyslipidemia. Totally, 559 subjects including 221 T2DM cases with dyslipidemia, 158 T2DM without dyslipidemia and 180 controls were enrolled. ACE genes polymorphism was evaluated by polymerase chain reaction (PCR), while MTHFR, FABP2, FTO genes polymorphisms were evaluated by PCR and restriction fragment length polymorphism (RFLP). Significant association of ACE and MTHFR genes polymorphisms were found in both group of cases [T2DM with dyslipidemia (P<0.001, and P=0.008, respectively) and T2DM without dyslipidemia (P=0.003, and P=0.010, respectively)] while FABP2 and FTO genes polymorphisms were significantly associated with T2DM without dyslipidemia (P=0.038, and P= 0.019, respectively). This study concludes that ACE, FABP2, FTO and MTHFR genes are associated with T2DM. Additionally, it also seems that ACE and MTHFR genes might be further associated with the development of dyslipidemia in T2DM cases.

Anthropometric and lipid profile of individuals with severe obesity carrying the fatty acid-binding protein-2 Thr54 allele

OBJECTIVE

The aim of this study was to evaluate the anthropometric and lipid profiles of individuals being considered for bariatric surgery, taking into account the presence of the Thr54 allele of the fatty acid-binding protein-2 (FABP-2) gene (rs1799883), and dietary intake.

METHODS

In a cross-sectional study, 120 participants being evaluated for bariatric surgery were asked to keep 24-h dietary records (R24 h) for 3 d, and to collect a 24-h urine sample for measurement of urea (as an assessment of the adequacy of food records) during day 3 of the diet record; a fasting blood sample for laboratory and genetic evaluations was collected.

RESULTS

When considering the whole sample, no significant differences were found; however, those who complied with the R24 h (n = 43) had more years of schooling and higher saturated fat intake, but lower weight and body mass index (BMI). When analyzing only the completers, the Thr54 allele carriers showed higher body weight (P = 0.02), BMI (P = 0.03), hip circumference (P = 0.02), basal metabolic rate (P = 0.02), and homeostatic model assessment-β (P = 0.04) compared with those who were homozygous for Ala54.

CONCLUSION

When the participants complied with the R24 h, Thr54 carriers were shown to have higher anthropometric parameters and higher homeostatic model assessment-β values than those with the wild genotype, but the lipid profile resulted similar in both carriers and noncarriers.

Deficiency of spermatogenesis and reduced expression of spermatogenesis-related genes in prefoldin 5-mutant mice

MM-1α is a c-Myc-binding protein and acts as a transcriptional co-repressor in the nucleus. MM-1α is also PDF5, a subunit of prefoldin that is chaperon comprised of six subunits and prevents misfolding of newly synthesized nascent polypeptides. Prefoldin also plays a role in quality control against protein aggregation. It has been reported that mice harboring the missense mutation L110R of MM-1α/PFD5 exhibit neurodegeneration in the cerebellum and also male infertility, but the phenotype of infertility has not been fully characterized. In this study, we first analyzed morphology of the testis and epididymis of L110R of MM-1α mice. During differentiation of spermatogenesis, spermatogonia, spermatocytes and round spermatids were formed, but formation of elongated spermatids was compromised in L110R MM-1α mice. Furthermore, reduced number/concentration of sperm in the epididymis was observed. MM-1α was strongly expressed in the round spermatids and sperms with round spermatids, suggesting that MM-1α affects the differentiation and maturation of germ cells. Changes in expression levels of spermatogenesis-related genes in mice testes were then examined. The fatty-acid-binding protein (fabp4) gene was up-regulated and three genes, including sperm-associated glutamate (E)-rich protein 4d (speer-4d), phospholipase A2-Group 3 (pla2g3) and phospholipase A2-Group 10 (pla2g10), were down-regulated in L110R MM-1α mice. L110R MM-1α and wild-type MM-1α bound to regions of up-regulated and down-regulated genes, respectively. Since these gene products are known to play a role in maturation and motility of sperm, a defect of at least MM-1α transcriptional activity is thought to induce expressional changes of these genes, resulting in male infertility.

Enterocyte fatty acid-binding proteins (FABPs): different functions of liver and intestinal FABPs in the intestine

Fatty acid-binding proteins (FABP) are highly abundant cytosolic proteins that are expressed in most mammalian tissues. In the intestinal enterocyte, both liver- (LFABP; FABP1) and intestinal FABPs (IFABP; FABP2) are expressed. These proteins display high-affinity binding for long-chain fatty acids (FA) and other hydrophobic ligands; thus, they are believed to be involved with uptake and trafficking of lipids in the intestine. In vitro studies have identified differences in ligand-binding stoichiometry and specificity, and in mechanisms of FA transfer to membranes, and it has been hypothesized that LFABP and IFABP have different functions in the enterocyte. Studies directly comparing LFABP- and IFABP-null mice have revealed markedly different phenotypes, indicating that these proteins indeed have different functions in intestinal lipid metabolism and whole body energy homeostasis. In this review, we discuss the evolving knowledge of the functions of LFABP and IFABP in the intestinal enterocyte.

Association between FABP2 Ala54Thr polymorphisms and type 2 diabetes mellitus risk: a HuGE Review and Meta-Analysis

Many studies have examined the association between the FABP2 (rs1799883) Ala54Thr gene polymorphism and type 2 diabetes mellitus risk (T2DM) in various populations, but their results have been inconsistent. To assess this relationship more precisely, A HuGE review and meta-analysis were performed. The PubMed and CNKI database was searched for case-control studies published up to April 2014. Data were extracted and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated. Ultimately, 13 studies, comprising 2020 T2DM cases and 2910 controls were included. Overall, for the Thr carriers (Ala/Thr and Thr/Thr) versus the wild-type homozygotes (Ala/Ala), the pooled OR was 1.18 (95% CI = 1.04–1.34, P = 0.062 for heterogeneity), for Thr/Thr versus Ala/Ala the pooled OR was 1.17 (95% CI = 1.05–1.41 P = 0.087 for heterogeneity). In the stratified analysis by ethnicity, the significantly risks were found among Asians but not Caucasians. This meta-analysis suggests that the FABP2 (rs1799883) Ala54Thr polymorphisms are associated with increased susceptibility to T2DM risk among Asians but not Caucasians.

A54T polymorphism in the fatty acid binding protein 2 studies in a Saudi population with type 2 diabetes mellitus

Background

Fatty acid-binding protein 2 (FABP2) is an intracellular protein expressed exclusively in the enterocytes of proximal small intestine. FABP2 has a high affinity for saturated and unsaturated long-chain fatty acids and is believed to be involved in the absorption and transport of dietary fatty acids.

Methods

This is a case–control study conceded in 438 T2DM cases and 460 subjects with normal glucose levels and non-obese considered as healthy controls. Allelic discrimination was performed using TaqMan single-nucleotide polymorphism was carried out by real time-polymerase chain reaction (RT-PCR) assays using purified DNA.

Results

Clinical data and anthropometric measurements except age, glucose levels and lipid profile of the patients were significantly different from those of the controls (p < 0.05). Statistical analyses failed to show any type of significant association of the polymorphism between cases and controls. However logistic regression analyses was suggests that the TT genotype is significantly associated with male patients (p = 0.001). None of the allele or genotypes of FABP2 A54T was associated with T2DM cases versus the controls (AT genotype, OR = 0.85 (0.64-1.12), p = 0.25; TT genotype, OR = 0.66 (0.39-1.11), p = 0.11; T allele, 0.82 (0.67-1.02), p = 0.08).

Conclusion

In conclusion, this study suggests that the above named variant in FABP2 gene is not potential contributor to the risk of T2DM and related traits in a Saudi population. However TT genotype is a risk factor for the disease in males.

Effects Ala54Thr polymorphism of FABP2 on obesity index and biochemical variable in response to a aerobic exercise training

The purpose of the current study was to investigate whether or not the FABP2 gene polymorphism modulated obesity indices, hemodynamic factor, blood lipid factor, and insulin resistance markers through 12-week aerobic exercise training in abdominal obesity group of Korean mid-life women. A total of 243 abdominally obese subjects of Korean mid-life women voluntarily participated in aerobic exercise training program for 12 weeks. Polymerase Chain Reaction with Restriction Fragment Length Polymorphism (PCR-RFLP) assay was used to assess the FABP2 genotype of the participants (117 of AA homozygotes, 100 of AT heterozygotes, 26 of TT homozygotes). Prior to the participation of the exercise training program, baseline obesity indices, hemodynamic factor, blood lipid factor, and insulin resistance markers were measured. All the measurements were replicated following the 12-week aerobic exercise training program, and then the following results were found. After 12-week aerobic exercise training program, wild type (Ala54Ala) and mutant type (Ala54Thr+Thr54Thr) significantly decreased weight (P > .001), BMI (P > .001), %bf (P > .001), waist circumference (P > .001), WHR (P > .001), muscle mass (wild type p < .022; mutant type P > .001), RHR (P > .001), viseceral adipose area (wild type p < .005; mutant type P > .001), subcutaneous area (P > .001), insulin (wild type p < .005; mutant type P > .001) and significantly increased VO2max (P > .001). And wild type significantly decresed NEFA (P > .05), glucose (P > .05), OGTT 120min glucose (P > .05) and significantly increased HDLC (p > .005). Mutant type significantly decreased SBP (P > .001), DBP (P > .01), TC (P > .01), LPL (P > .05), LDL (P > .001), HOMA index (P > .01). The result of the present study represents that regular aerobic exercise training may beneficially prevent obesity index, blood pressure, blood lipids and insulin resistance markers independent of FABP Ala54Thr wild type and mutant type.

Association of genetic polymorphism of PPARγ-2, ACE, MTHFR, FABP-2 and FTO genes in risk prediction of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a non-autoimmune, complex, heterogeneous and polygenic metabolic disease condition characterized by persistent elevated blood glucose levels (hyperglycemia). India as said to be the diabetic capital of the world is likely to experience the largest increase in T2DM and a greater number of diabetic individuals in the world by the year 2030. Identification of specific genetic variations in a particular ethnic group has a critical role in understanding the risk of developing T2DM in a much efficient way in future. These genetic variations include numerous types of polymorphisms among which single nucleotide polymorphisms (SNPs) is the most frequent. SNPs are basically located within the regulatory elements of several gene sequences. There are scores of genes interacting with various environmental factors affecting various pathways and sometimes even the whole signalling network that cause diseases like T2DM. This review discusses the biomarkers for early risk prediction of T2DM. Such predictions could be used in order to understand the pathogenesis of T2DM and to better diagnostics, treatment, and eventually prevention.

Phytochemicals targeting genes relevant for type 2 diabetes

Nutrigenomic approaches based on ethnopharmacology and phytotherapy concepts have revealed that type 2 diabetes mellitus (T2DM) may be susceptible to dietary intervention. Interaction between bioactive food components and the genome may influence cell processes and modulate the onset and progression of the disease. T2DM, characterized by insulin resistance and beta cell dysfunction, is one of the leading causes of death and disability. Despite the great advances that have been made in the understanding and management of this complex, multifactorial disease, T2DM has become a worldwide epidemic in the 21st century. Population and family studies have revealed a strong genetic component of T2DM, and a number of candidate genes have been identified in humans. Variations in the gene sequences such as single nucleotide polymorphisms, explain the individual differences in traits like disease susceptibility and response to treatment. A clear understanding of how nutrients affect the expression of genes should facilitate the development of individualized intervention and, eventually, treatment strategies for T2DM. Review of the literature identified many phytochemicals/extracts from traditional medicinal plants that can target diabetogenic genes. This review focuses on the genetic aspects of T2DM, nutrient modification of genes relevant for diabetes, and future prospects of nutritional therapy of T2DM.

Association of angiotensin-converting enzyme (ACE) and fatty acid binding protein 2 (FABP2) genes polymorphism with type 2 diabetes mellitus in Northern India

BACKGROUND

Type 2 diabetes mellitus (T2DM) is growing in an epidemic manner across the world with an expected doubling of the incidence to millions of affected individuals in the last decades. At present, adequate data are not available regarding the ACE and FABP2 polymorphisms and their susceptibility with T2DM cases in the North Indian population. Thus we conceived the need for further study of ACE (I/D) and FABP2 (Ala54Thr) genes polymorphism and its susceptibility to T2DM in the North Indian population.

MATERIALS AND METHODS

In this study, a total of 300 subjects (including 190 T2DM cases and 110 controls) participated. ACE and FABP2 gene polymorphisms in the cases and controls were evaluated by polymerase chain reaction and restriction fragment length polymorphism.

RESULTS

The frequencies of ACE I/I, I/D and D/D genotypes in T2DM cases and controls were 28.73%, 55.17%, 16.09% and 13.63%, 57.95%, 28.40%, respectively. The frequencies of FABP2 Ala54Ala, Ala54Thr and Thr54Thr in T2DM cases were 18.39%, 66.66%, 14.94% and 22.72%, 61.36%, 15.90% in controls, respectively. ACE I/I genotype was significantly more frequent in cases as compared to controls (p = 0.003, χ(2) = 9.13).

CONCLUSION

It appears that the ACE I/I genotype frequency was significantly higher in the T2DM cases as compared to the controls.

The Human Obesity Gene Map: The 2003 Update

This is the tenth update of the human obesity gene map, incorporating published results up to the end of October 2003 and continuing the previous format. Evidence from single-gene mutation obesity cases, Mendelian disorders exhibiting obesity as a clinical feature, quantitative trait loci (QTLs) from human genome-wide scans and animal crossbreeding experiments, and association and linkage studies with candidate genes and other markers is reviewed. Transgenic and knockout murine models relevant to obesity are also incorporated (N = 55). As of October 2003, 41 Mendelian syndromes relevant to human obesity have been mapped to a genomic region, and causal genes or strong candidates have been identified for most of these syndromes. QTLs reported from animal models currently number 183. There are 208 human QTLs for obesity phenotypes from genome-wide scans and candidate regions in targeted studies. A total of 35 genomic regions harbor QTLs replicated among two to five studies. Attempts to relate DNA sequence variation in specific genes to obesity phenotypes continue to grow, with 272 studies reporting positive associations with 90 candidate genes. Fifteen such candidate genes are supported by at least five positive studies. The obesity gene map shows putative loci on all chromosomes except Y. Overall, more than 430 genes, markers, and chromosomal regions have been associated or linked with human obesity phenotypes. The electronic version of the map with links to useful sites can be found at http://obesitygene.pbrc.edu.

The Human Obesity Gene Map: The 2004 Update

This paper presents the eleventh update of the human obesity gene map, which incorporates published results up to the end of October 2004. Evidence from single-gene mutation obesity cases, Mendelian disorders exhibiting obesity as a clinical feature, transgenic and knockout murine models relevant to obesity, quantitative trait loci (QTLs) from animal cross-breeding experiments, association studies with candidate genes, and linkages from genome scans is reviewed. As of October 2004, 173 human obesity cases due to single-gene mutations in 10 different genes have been reported, and 49 loci related to Mendelian syndromes relevant to human obesity have been mapped to a genomic region, and causal genes or strong candidates have been identified for most of these syndromes. There are 166 genes which, when mutated or expressed as transgenes in the mouse, result in phenotypes that affect body weight and adiposity. The number of QTLs reported from animal models currently reaches 221. The number of human obesity QTLs derived from genome scans continues to grow, and we have now 204 QTLs for obesity-related phenotypes from 50 genome-wide scans. A total of 38 genomic regions harbor QTLs replicated among two to four studies. The number of studies reporting associations between DNA sequence variation in specific genes and obesity phenotypes has also increased considerably with 358 findings of positive associations with 113 candidate genes. Among them, 18 genes are supported by at least five positive studies. The obesity gene map shows putative loci on all chromosomes except Y. Overall, >600 genes, markers, and chromosomal regions have been associated or linked with human obesity phenotypes. The electronic version of the map with links to useful publications and genomic and other relevant sites can be found at http://obesitygene.pbrc.edu.

IntestinalFABP2A54T Polymorphism: Association with Insulin Resistance and Obesity in Women

OBJECTIVE

To assess the association between the Ala54Thr genetic polymorphism of the fatty acid-binding protein 2 (FABP2) gene with insulin resistance and obesity.

RESEARCH METHODS AND PROCEDURES

According to a sampling scheme based on BMI, 33 adult obese women (BMI > or = 30) and 30 adult normal-weight women (BMI > 18.5 and < 25 kg/m(2)) were recruited for this study. Women with chronic inflammatory diseases or acute pathology were excluded. Glucose, insulin, leptin, lipids, and tumor necrosis factor alpha (TNF alpha) were measured in fasting plasma samples. Insulin resistance was estimated through the homeostasis model assessment for insulin resistance method. The Ala54Thr allelic variant was determined by polymerase chain reaction, followed by restriction fragment-length polymorphism analysis.

RESULTS

The Thr54 allele was more frequent in obese than in nonobese women (47.0% vs. 31.7; p = 0.08). Among obese women, higher TNF alpha concentrations were found when comparing the Thr54/Thr54 genotype (30.0 +/- 7.1 pg/mL) with either the Ala54/Thr54 genotype (21.2 +/- 8.4 pg/mL) or the Ala54/Ala44 genotype (20.1 +/- 7.0 pg/mL) (p < 0.05). In addition, higher fasting plasma insulin and leptin levels were found among Thr54/Thr54 homozygotes compared with the other genotypes (p < 0.05).

DISCUSSION

Our results suggest that the Ala54Thr polymorphism of the FABP2 gene is associated with obesity and insulin resistance. The effect of this polymorphism might be mediated by elevated production of TNF alpha.

Meta-analysis on the effect of the Ala54Thr polymorphism of the fatty acid-binding protein 2 gene on body mass index

BACKGROUND AND AIM

The results from studies published on the association of fatty acid-binding protein 2 (FABP2) Ala54Thr polymorphism with body mass index (BMI) are conflicting. In this meta-analysis, we investigated the association of the FABP2 Ala54Thr polymorphism with BMI.

METHODS AND RESULTS

We searched for articles published prior to June 2009 using PubMed, HugeNavigator and China National Knowledge Internet. The languages were limited to English and Chinese. Data on BMI were collected. A pooled weighted mean difference (WMD), together with 95% confidence interval (CI), was used for this meta-analysis. A total of 27 studies with 10 974 subjects were included in this meta-analysis. The pooled effect for dominant, recessive and co-dominant model comparisons did not suggest the significant association between the FABP2 Ala54Thr polymorphism and BMI in overall populations: WMD(fixed effects)=-0.00, 95% CI: (-0.16 to 0.15), p=0.99, WMD(random effects)=-0.00, 95% CI: (-0.16 to 0.15), p=0.99, p(Q)=0.77, I(2)=0%, WMD(fixed effects)=-0.12, 95% CI: (-0.39 to 0.14), p=0.35, WMD(random effects)=-0.12, 95% CI: (-0.39 to 0.14), p=0.35, p(Q)=0.47, I(2)=0% and WMD(fixed effects)=0.07, 95% CI: (-0.11 to 0.25), p=0.45, WMD(random effects)=0.07, 95% CI: (-0.11 to 0.25), p=0.45, p(Q)=0.90, I(2)=0%, respectively. The results from the comparisons of ThrThr versus AlaAla and AlaThr versus AlaAla showed no evidence that the FABP2 Ala54Thr polymorphism is significantly associated with BMI in overall populations (p>0.05). All the results from the subgroup analyses for these genetic models comparisons were not significant (p>0.05).

CONCLUSIONS

Our meta-analysis does not support the association between the FABP2 Ala54Thr polymorphism and BMI.

APOE and FABP2 Polymorphisms and History of Myocardial Infarction, Stroke, Diabetes, and Gallbladder Disease

Dysfunctional lipid metabolism plays a central role in pathogenesis of major chronic diseases, and genetic factors are important determinants of individual lipid profiles. We analyzed the associations of two well-established functional polymorphisms (FABP2 A54T and APOE isoforms) with past and family histories of 1492 population samples. FABP2-T54 allele was associated with an increased risk of past history of myocardial infarction (odds ratio (OR) = 1.51). Likewise, the subjects with APOE4, compared with E2 and E3, had a significantly increased risk of past history myocardial infarction (OR = 1.89). The OR associated with APOE4 was specifically increased in women for past history of myocardial infarction but decreased for gallstone disease. Interactions between gender and APOE isoforms were also significant or marginally significant for these two conditions. FABP2-T54 allele may be a potential genetic marker for myocardial infarction, and APOE4 may exert sex-dependent effects on myocardial infarction and gallbladder disease.

Metabolic syndrome and ALA54THR polymorphism of fatty acid-binding protein 2 in obese patients

The prevalence of metabolic syndrome (MS) has been estimated to be approximately 25% of the population at large. A transition G to A at codon 54 of fatty acid-binding protein 2 (FABP2) results in an amino acid substitution (ala54 to Thr54), and this polymorphism was associated with some cardiovascular risk factors. The aim of our study was to investigate the relationship between MS and Thr54 polymorphism in the FABP2 gene in obese patients. A population of 750 (body mass index >30) obese patients was analyzed in cross-sectional survey. Bioimpedance, blood pressure, and serial assessment of nutritional intake with 3-day written food records and biochemical analysis were performed. The statistical analysis was performed for the combined Ala54/Thr54 and Thr54/Thr54 as a mutant group and wild-type Ala54/Ala54 as second group. Prevalence of MS with Adult Treatment Panel III definition was 49.7% (373 patients; 24.9% male and 75.1% female), and 50.3% of the patients had no MS (n = 377; 34.2% male and 65.8% female). Prevalence of FABP genotypes was similar in patients with MS (55.5% wild genotype and 44.5% mutant genotype) and without MS (54.6% wild genotype and 45.4% mutant genotype). Prevalence of each criteria of MS was calculated in wild- and mutant-type genotypes, without statistical differences. No differences in anthropometric and biochemical parameters were detected between genotypes in the same group of MS. The finding of our study is the lack of association of the Thr54/Ala54 and Thr54/Thr54 FABP2 genotypes with MS.

Association of the fatty acid-binding protein 2 gene Ala54Thr polymorphism with insulin resistance and blood glucose: a meta-analysis in 13451 subjects

BACKGROUND

The results from the published studies on the association of fatty acid-binding protein 2 (FABP2) Ala54Thr polymorphism with insulin resistance and blood glucose are conflicting. In this meta-analysis, we investigated the association of the FABP2 Ala54Thr polymorphism with insulin resistance and blood glucose.

METHODS

We collected data on fasting blood glucose and fasting insulin, 2-h blood glucose (2-h BG) and 2-h insulin (2-h insulin), and homeostasis model assessment insulin resistance index. A dominant model was used for this meta-analysis.

RESULTS

Thirty-one studies with 13 451 subjects were included in this meta-analysis. The carriers of Thr54 allele have significantly higher homeostasis model assessment insulin resistance index and marginally higher fasting insulin than the non-carriers: standardized mean difference (SMD) = 0.07, 95% confidence interval (CI, 0.02, 0.12), p = 0.007, p(heterogeneity) = 0.19 and SMD = 0.08, 95% CI (-0.01, 0.17), p = 0.07, p(heterogeneity) < 0.00001, respectively. A borderline significant association between the FABP2 Ala54Thr polymorphism and an increased 2-h BG was also detected under the dominant model: SMD = 0.10, 95% CI (0.00, 0.20), p = 0.05, p(heterogeneity) = 0.09. In addition, a borderline association between this polymorphism and an increased fasting blood glucose in populations of other ethnic origins was detected under the dominant model: SMD = 0.11, 95% CI (-0.00, 0.23), p = 0.06, p(heterogeneity) = 0.03.

CONCLUSIONS

Our meta-analysis suggests that the Thr54 allele of the FABP2 Ala54Thr is weakly associated with a higher degree of insulin resistance, higher level of fasting insulin and higher level of 2-h BG. Our meta-analysis also suggests a weak association between this polymorphism and an increased fasting blood glucose in populations of other ethnic origins under the dominant model.

Thr54 allele of fatty-acid binding protein 2 gene is associated with obesity but not type 2 diabetes mellitus in a Caucasian population

AIM

The fatty acid-binding protein 2 (FABP2) A54T polymorphism has been associated with type 2 diabetes mellitus (T2DM) and obesity in many but not all studies. Our aim was to investigate possible associations of FABP2 A54T polymorphism with T2DM and/or obesity in a Greek Caucasian population.

METHODS

242 subjects with T2DM and 188 control subjects were genotyped for the FABP2 A54T polymorphism using PCR-RFLP method. Of the total subjects included in both groups, 172 were classified as obese (BMI >or= 30 kg/m(2)) and 258 were classified as nonobese (BMI <30 kg/m(2)).

RESULTS

In the whole population, 218 subjects (50.7%) were genotyped as AA, 175 subjects (40.7%) as AT, and 37 subjects (8.6%) as TT for the FABP2 A54T polymorphism. According to the dominant model, the frequency of AA genotype was significantly lower in obese than in nonobese subjects (43.0% vs 55.8%, p=0.009). No significant difference was observed in genotypes between diabetic and nondiabetic subjects. According to the additive model, the presence of TT genotype was significantly associated with obesity after adjusting for age, sex, and the presence of T2DM (OR 2.32, p=0.028).

CONCLUSION

FABP2 A54T polymorphism may help identify Caucasian subjects at risk for obesity.

Association of genetic variants with myocardial infarction in Japanese individuals with metabolic syndrome

OBJECTIVE

The purpose of the present study was to identify genetic variants that confer susceptibility to myocardial infarction (MI) in individuals with metabolic syndrome (MetS).

METHODS

The study population comprised 1887 Japanese individuals with MetS, including 773 subjects with MI and 1114 controls. The genotypes for 136 polymorphisms of 97 candidate genes were determined.

RESULTS

An initial screen by the chi-square test revealed that seven polymorphisms were significantly (false discovery rate<0.05) associated with the prevalence of MI in individuals with MetS. Subsequent multivariable logistic regression analysis with adjustment for covariates revealed that the G-->A (Ser89Asn) polymorphism of UTS2 [odds ratio (OR), 1.90; 95% confidence interval (CI), 1.18-3.08], the 2445G-->A (Ala54Thr) polymorphism of FABP2 (OR, 1.72; 95% CI, 1.23-2.40), the -11377C-->G polymorphism of ADIPOQ (OR, 1.43; 95% CI, 1.15-1.79), the -231A-->G polymorphism of EDNRA (OR, 0.65; 95% CI, 0.48-0.89), and the -108/3G-->4G polymorphism of PDX1 (OR, 0.64; 95% CI, 0.48-0.87) were significantly (P<0.05) associated with MI. The variant alleles of UTS2, FABP2, and ADIPOQ were risk factors for MI, whereas the variant alleles of EDNRA and PDX1 were protective against this condition. A stepwise forward selection procedure demonstrated that UTS2, FABP2, ADIPOQ, EDNRA, and PDX1 genotypes were significant (P<0.05) and independent determinants of MI.

CONCLUSIONS

Determination of genotypes for these polymorphisms of UTS2, FABP2, ADIPOQ, EDNRA, and PDX1 may prove informative for assessment of the genetic risk for MI in Japanese individuals with MetS.

Severity of metabolic syndrome unfavorably influences oxidative stress and fatty acid metabolism in men

Metabolic syndrome (MS) is defined by the clustering of several components (MSC), which include abdominal fat accumulation, impaired glucose homeostasis, hypertriglyceridemia, lowered high-density lipoprotein cholesterol, increased blood pressure, and hyperuricemia. Metabolic syndrome is also accompanied by increased oxidative stress and inflammation as well as by altered composition of esterified fatty acids (FA). Therefore, we have investigated 210 men (categorized into six groups with increasing number of MSC) to find trends in the extent of oxidative stress, FA pattern and frequency of pathological alleles of the selected candidate genes for lipid metabolism. Increasing number of MSC was connected with the raised serum glucose and insulin, increased concentrations of conjugated dienes in low-density lipoprotein (all p < 0.0001), and high frequency of e2 and e4 alleles of the apolipoprotein E gene (p < 0.005). However, the last significance was lost after the adjustment for age. The incidence of 54Thr allele for intestinal isoform of the fatty acid-binding protein (FABP-2) gene was comparable in all groups. The most important findings were the raised content of saturated FA and the increased activities of Delta9 and Delta6 desaturases (all p < 0.0001), and the decreased content of polyunsaturated FA n-6 family and the decreased activity of Delta5 desaturase (both p < 0.001) in connection with increasing number of MSC. In conclusion, the severity of MS is connected with the progression of oxidative stress and the unfavorable changes in the FA composition. These changes are independent of the studied gene polymorphisms.

Dietary, physiological, genetic and pathological influences on postprandial lipid metabolism

Most of diurnal time is spent in a postprandial state due to successive meal intakes during the day. As long as the meals contain enough fat, a transient increase in triacylglycerolaemia and a change in lipoprotein pattern occurs. The extent and kinetics of such postprandial changes are highly variable and are modulated by numerous factors. This review focuses on factors affecting postprandial lipoprotein metabolism and genes, their variability and their relationship with intermediate phenotypes and risk of CHD. Postprandial lipoprotein metabolism is modulated by background dietary pattern as well as meal composition (fat amount and type, carbohydrate, protein, fibre, alcohol) and several lifestyle conditions (physical activity, tobacco use), physiological factors (age, gender, menopausal status) and pathological conditions (obesity, insulin resistance, diabetes mellitus). The roles of many genes have been explored in order to establish the possible implications of their variability in lipid metabolism and CHD risk. The postprandial lipid response has been shown to be modified by polymorphisms within the genes for apo A-I, A-IV, A-V, E, B, C-I and C-III, lipoprotein lipase, hepatic lipase, fatty acid binding and transport proteins, microsomal triglyceride transfer protein and scavenger receptor class B type I. Overall, the variability in postprandial response is important and complex, and the interactions between nutrients or dietary or meal compositions and gene variants need further investigation. The extent of present knowledge and needs for future studies are discussed in light of ongoing developments in nutrigenetics.

Effect of the interaction between the fatty acid binding protein 2 gene Ala54Thr polymorphism and dietary fatty acids on peripheral insulin sensitivity: a cross-sectional study

BACKGROUND

The intestinal fatty acid-binding protein (FABP2) is involved in the intracellular transport and metabolism of fatty acids and may affect insulin sensitivity and glucose metabolism.

OBJECTIVE

The objective was to study the effect of interaction between the Ala54Thr polymorphism of the FABP2 gene (FABP2) and the type of dietary cooking oil used on peripheral insulin sensitivity in a population from southern Spain.

DESIGN

The study was cross-sectional. Anthropometric measurements were obtained for 1226 persons aged 18-65 y selected randomly from the municipal census of Pizarra, Spain. An oral-glucose-tolerance test was given to 1020 of these persons. Insulin resistance was measured by homeostasis model assessment. Samples of the cooking oil being used were taken from the kitchens of a random subset of 538 persons.

RESULTS

Persons who consumed sunflower oil and who also had the Thr54 variant had higher insulin resistance than did those who consumed olive oil (P = 0.01). We detected an interaction between the Ala54Thr polymorphism and the type of oil consumed that accounted for the variance in insulin resistance (P = 0.02).

CONCLUSIONS

The effect of dietary fatty acids on the populational pattern of insulin resistance is not independent of the Ala54Thr polymorphism of FABP2. An interaction existed between this polymorphism and the intake of dietary fats in a population with a high intake of monounsaturated fatty acids.

Codon 54 polymorphism of the fatty acid binding protein (FABP) 2 gene is associated with increased cardiovascular risk in the dyslipidemic diabetic participants of the veterans affairs HDL intervention trial (VA-HIT)

The threonine (Thr) for alanine (Ala) codon 54 polymorphism of the fatty acid binding protein (FABP) 2 gene, when compared to the wild type, is associated with dyslipidemia. Since dyslipidemia is common in diabetes and is associated with increased cardiovascular risk, we tested the hypothesis that Thr-54 is associated with increased cardiovascular risk in patients with diabetes. The secondary prevention veterans affairs HDL intervention trial (VA-HIT) was carried out in patients with dyslipidemia. The DNA of trial participants (n=776) was screened for the Thr-54 polymorphism and cardiovascular endpoints were monitored. The polymorphism was detected in 370 (47.7%). For first occurrence of the primary endpoint [myocardial infarction (MI) or coronary heart disease (CHD) death] the hazard ratio (HR) and confidence intervals (Cox proportional hazards model) was 2.5 (1.2, 5.3) p=.02 in diabetic carriers of Thr-54 versus carriers without diabetes or fasting glucose >7 mmol/L. For the expanded endpoint (stroke, MI or CHD death), the corresponding HR was 3.0 (1.4, 5.4) p=.0003 and for the stroke alone the corresponding HR was 3.5 (1.4-8.9) p=.01. The higher cumulative incidence of the expanded endpoint in diabetic participants carrying the FABP2 polymorphism versus non-diabetic carriers was consistently present throughout the 5 years of the study (p=.0002). We conclude that based on the VA-HIT data, the Thr-54 polymorphism of the FABP2 gene is associated with a 2-3.5-fold increase in cardiovascular risk in dyslipidemic men with diabetes compared to their non-diabetic counterparts.

FABP2 Ala54Thr polymorphism and diabetes in Chilean elders

OBJECTIVE

The FABP2 Ala54Thr polymorphism has been associated with insulin resistance and diabetes in several populations. The aim of this study was to estimate the prevalence of FABP2 genotypes in 223 Chilean subjects (136 women and 87 men aged 65-79 years) and its association with type 2 diabetes in a 4 years follow-up.

METHODS

Glucose, Insulin and lipids were measured in fasting plasma samples. Insulin resistance was estimated through the homeostasis model assessment. Diabetes was diagnosed according ADA criteria. The Ala54Thr allelic variant was determined by polymerase chain reaction and restriction fragment-length polymorphism analysis. Logistic regression techniques were used to assess gene-disease associations.

RESULTS

Genotype frequencies were estimated as 30.5, 49.3 and 20.2% for the Ala/Ala, Ala/Thr and Thr/Thr, respectively. The crude OR for the association between Thr54 carriers and diabetes was estimated as 2.18 (1.12-4.24). The corresponding OR for the association between Thr54 carriers with Metabolic Syndrome was 1.06 (0.59-1.88). After adjustment by BMI and age, a significant association persists for Thr54Thr carriers and diabetes (OR 2.70; 95% CI 1.113-6.527). The 4-year cumulative incidence of diabetes was higher in Thr carriers than in non-carriers (20.1% versus 8.5%; p<0.04). The adjusted association between Thr54Thr polymorphism and diabetes incidence was OR 3.84 (95% CI: 1.140-12.910)

CONCLUSION

Our results strongly suggest an association between the Ala54Thr polymorphism of FABP2 with diabetes, revealing a genetic dosage effect regarding its association with diabetes in Chilean elders.

[Correlation of FABP2-A54T polymorphism and the metabolic syndrome in Maros County of Romania]

OBJECTIVE

The FABP2 (intestinal fatty acid-binding protein) gene is expressed in the intestinal epithelial cells and codes for a protein involved in the fatty acid metabolism. We investigated the association of the A54T polymorphism of the FABP2 gene with the metabolic syndrome defined according to the diagnostic criteria recommended by the IDF in 2005, in our region (Marosvásárhely - Tg. Mures, Romania).

RESEARCH DESIGN AND METHODS

A case-control study was carried out on 144 metabolic syndrome patients and 73 healthy persons with similar age and lifestyle. Insulin resistance was measured by the HOMA and QUICKI indices, and gene polymorphism was analyzed with PCR followed by restriction enzyme digestion with Hha I.

RESULTS

The T54 allele was more frequent in the metabolic syndrome group than in controls (35.71% vs. 28.08%, p < 0.05). In the presence of the T54 allele we have noticed a slight but statistically significant risk, more marked in the case of TT homozygotes (TT vs. AT + AA: OR = 4.31, CI 95% 1.21-5.29, p = 0.015 and TT vs. AA: OR = 4.61, CI95%: 1.24-7.03, p = 0.0195). No significant differences of the followed metabolic parameters were observed between persons having different genotypes in the two study groups.

CONCLUSIONS

These results suggest that the FABP2 T54 allele may have a minor contribution to the metabolic syndrome in our region.

The human intestinal fatty acid binding protein (hFABP2) gene is regulated by HNF-4alpha

The cytosolic human intestinal fatty acid binding protein (hFABP2) is proposed to be involved in intestinal absorption of long-chain fatty acids. The aim of this study was to investigate the regulation of hFABP2 by the endodermal hepatocyte nuclear factor 4alpha (HNF-4alpha), involved in regulation of genes of fatty acid metabolism and differentiation. Electromobility shift assays demonstrated that HNF-4alpha binds at position -324 to -336 within the hFABP2 promoter. Mutation of this HNF-4 binding site abolished the luciferase reporter activity of hFABP2 in postconfluent Caco-2 cells. In HeLa cells, this mutation reduced the activation of the hFABP2 promoter by HNF-4alpha by about 50%. Thus, binding element at position -336/-324 essentially determines the transcriptional activity of promoter and may be important in control of hFABP2 expression by dietary lipids and differentiation. Studying genotype interactions of hFABP2 and HNF-4alpha, that are both candidate genes for diabetes type 2, may be a powerful approach.

Thr54 allele carriers of the Ala54Thr variant of FABP2 gene have associations with metabolic syndrome and hypertriglyceridemia in urban South Indians

The intestinal fatty acid-binding protein gene is proposed as a candidate gene for diabetes because the protein it codes is involved in fatty acid absorption and metabolism. This study investigates the association of the Ala54Thr variant of the intestinal fatty acid-binding protein gene on type 2 diabetes mellitus and other related metabolic traits in Asian Indians. Ala54Thr polymorphism was genotyped by using polymerase chain reaction-restriction fragment length polymorphism in unrelated 773 type 2 diabetic and 899 normal glucose-tolerant (NGT) subjects, randomly chosen from the Chennai Urban Rural Epidemiology Study, an ongoing population-based study in South India. The Ala54Thr polymorphism was not associated with type 2 diabetes mellitus or obesity. However, genotype-phenotype study revealed that the NGT subjects carrying the Thr54 allele had significantly higher 2-hour plasma glucose (P = .007), glycated hemoglobin (P = .004), 2-hour insulin (P = .027), and fasting low-density lipoprotein cholesterol (P = .032) levels compared with those with the Ala54 allele. Normal glucose-tolerant subjects with Ala54Thr and Thr54Thr genotypes had significantly higher fasting serum triglyceride levels (P = .003) compared with those with Ala54Ala. The subjects were stratified into those with hypertriglyceridemia (serum triglyceride levels >or=150 mg/dL) and those without. The odds ratio for hypertriglyceridemia for the individuals carrying the Ala54Thr genotype was 1.491 (95% confidence interval [CI], 1.22-1.83, P < .0001), and for those carrying the Thr54Thr genotype, it was 1.888 (95% CI, 1.34-2.67; P < .0001). Subjects were also stratified into those with metabolic syndrome (MS) and those without, according to modified Adult Treatment Panel III guidelines. The odds ratio (adjusted for age and sex) for MS for the individuals carrying the Ala54Thr genotype was 1.240 (95% CI, 1.02-1.51; P = .03), whereas for those carrying the Thr54Thr genotype, it was 1.812 (95% CI, 1.28-2.57; P = .001). Carriers of the Thr54 allele have associations with MS and hypertriglyceridemia in this urban South Indian population.

Linkage and Association Studies of the Susceptibility Genes for Type 2 Diabetes

Type 2 diabetes mellitus (T2DM) is a complex disease characterized by hyperglycemia, insulin resistance, and impaired insulin secretion. T2DM is under strong genetic control. Identification and characterization of genes involved in determining T2DM will contribute to a greater understanding of the pathogenesis of T2DM, and ultimately might lead to the development of better diagnosis, prevention and treatment strategies. Efforts to identify T2DM susceptibility genes have focused on candidate gene approach (association studies) and genome-wide scans (linkage analyses). In this article, we review the current status for mapping and identification of genes for T2DM, with a focus on some promising regions (or genes) and future prospects.

The human obesity gene map: the 2005 update

This paper presents the 12th update of the human obesity gene map, which incorporates published results up to the end of October 2005. Evidence from single-gene mutation obesity cases, Mendelian disorders exhibiting obesity as a clinical feature, transgenic and knockout murine models relevant to obesity, quantitative trait loci (QTL) from animal cross-breeding experiments, association studies with candidate genes, and linkages from genome scans is reviewed. As of October 2005, 176 human obesity cases due to single-gene mutations in 11 different genes have been reported, 50 loci related to Mendelian syndromes relevant to human obesity have been mapped to a genomic region, and causal genes or strong candidates have been identified for most of these syndromes. There are 244 genes that, when mutated or expressed as transgenes in the mouse, result in phenotypes that affect body weight and adiposity. The number of QTLs reported from animal models currently reaches 408. The number of human obesity QTLs derived from genome scans continues to grow, and we now have 253 QTLs for obesity-related phenotypes from 61 genome-wide scans. A total of 52 genomic regions harbor QTLs supported by two or more studies. The number of studies reporting associations between DNA sequence variation in specific genes and obesity phenotypes has also increased considerably, with 426 findings of positive associations with 127 candidate genes. A promising observation is that 22 genes are each supported by at least five positive studies. The obesity gene map shows putative loci on all chromosomes except Y. The electronic version of the map with links to useful publications and relevant sites can be found at http://obesitygene.pbrc.edu.

Comparison of the acute response to meals enriched with cis- or trans-fatty acids on glucose and lipids in overweight individuals with differing FABP2 genotypes

Trans-fatty acids have been implicated as a risk factor for cardiovascular disease and diabetes. In addition, a polymorphism at codon 54 (Ala54Thr) in the fatty acid-binding protein 2 (FABP2) gene has been suggested to modify an interaction between dietary fat and insulin sensitivity. We examined the postprandial metabolic profiles after meals enriched with C18:1trans- relative to a similar meal with C18:1cis-fatty acid in individuals who were either FABP2 Ala54 homozygotes or Thr54 carriers. Moderately overweight men and women ate 2 breakfast test meals, separated by 1 week, each providing 40% of their daily energy requirement and containing 50% of energy as fat. In one meal, 10% of energy was from C18:1trans, and in the other meal, the C18:1trans was replaced with C18:1cis. Metabolic parameters were assessed during an 8-hour period. Insulin and C-peptide levels increased more after the C18:1trans meal, and this was associated with a greater fall in free fatty acids. Postprandial glucose levels and oxidation of fatty acids and carbohydrate were not different between the 2 test meals. The Thr54 allele for FABP2 increased the rise in postprandial glucose but not triacylglycerols. Fractional triacylglycerol synthetic rates were higher after consumption of the C18:1trans meal relative to the C18:1cis meal only in Thr54 carriers. These data show that a single meal enriched with C18:1trans-fatty acids can significantly increase insulin resistance, and that in the presence of the FABP2 Thr54 allele, may contribute to increased partitioning of glucose to triacylglycerols and insulin resistance.

Association of the intestinal fatty acid-binding protein Ala54Thr polymorphism and abdominal adipose tissue in African-American and Caucasian women

Genetic variants in the intestinal fatty acid-binding protein-2 (FABP2) gene have been associated with body composition phenotypes. We examined the association between the Ala(54)Thr variant in the FABP2 gene and levels of visceral (VAT) and sc (SAAT) abdominal fat in a group of 223 premenopausal African-American (n = 103) and Caucasian (n = 120) women. Subjects were genotyped for the marker. In addition, body composition was assessed by dual energy x-ray absorptiometry, and VAT was determined from a single computed tomography scan. The frequency of the Thr mutant allele did not differ significantly by ethnic group. After adjusting for total body fat, total abdominal adipose tissue (TAT) and SAAT were significantly lower in carriers of either one or two copies of the mutant Thr allele (P < 0.01). There was no association between total fat mass or VAT and the FABP2 polymorphism. Separate analyses by ethnic group showed that the association between the polymorphism and TAT and SAAT was observed in Caucasian (P < 0.01), but not in African-American (not significant), women. We conclude that women carriers of the FABP2 Thr allele have lower TAT and SAAT than noncarriers of the mutation. This association is present in Caucasian, but not in African-American, women.

Thr54 allele of the FABP2 gene affects resting metabolic rate and visceral obesity

We investigated the relationship between Ala54Thr variant allele of the fatty acid-binding protein 2 (FABP2) gene (Ala54Thr) and development of obesity in Japanese obese women. FABP2 genotypes were determined with a fluorescent allele-specific DNA primer assay system. Body weight, waist and hip circumference, amounts of visceral and subcutaneous white adipose tissue measured by computed tomography (CT) were compared between subjects with Thr allele and without Thr allele before and after the diet and exercise therapy in 80 Japanese obese women. The frequency of the Thr54 allele did not differ between obese and control subjects (0.388 versus 0.329, respectively). In subjects with Ala/Thr and Thr/Thr genotype, adjusted resting metabolic rate (RMR) was significantly lower than the subjects with Ala/Ala genotype. Subjects with the Thr54 allele showed significantly greater waist circumference after diet and exercise therapy than subjects with Ala/Ala genotype. They also demonstrated greater body weight at 20 years of age compared to subjects with Ala/Ala genotype. In conclusion, Thr54 allele of FABP2 has associations with lower adjusted resting metabolic rate, resistance in reducing visceral white adipose tissue (WAT) and early onset of obesity in Japanese obese women.

Comparison of Gene Expression in Intra-Abdominal and Subcutaneous Fat: A Study of Men with Morbid Obesity and Nonobese Men Using Microarray and Proteomics

Extent of intra-abdominal fat had significant linear relations with six metabolic coronary risk factors: systolic and diastolic blood pressure, fasting blood concentrations of glucose, high density lipoprotein (HDL) cholesterol, triglyceride, and plasminogen activator inhibitor-1. Tumor necrosis factor-alpha and adiponectin can be biological mediators from the intra-abdominal fat to the metabolic coronary risk factors. Complementarily, we describe a new study that will analyze the gene expression in intra-abdominal and subcutaneous fat on mRNA and protein level using high throughput methods. The study will elucidate further whether intra-abdominal obesity is the common denominator for the different components of the metabolic syndrome.

Intestinal fatty acid binding protein and microsomal triglyceride transfer protein polymorphisms in French-Canadian youth

Growing evidence suggests an association between lipid abnormalities and fatty acid binding protein (FABP) and microsomal triglyceride transfer protein (MTP) gene variants. Our objectives were to determine whether Ala54Thr FABP2 and G-493T MTP polymorphisms are associated with increased risks of insulin resistance syndrome (IRS) in youth and/or modify the expression of accompanying dyslipidemia. Our study of 1,742 French-Canadians aged 9, 13, and 16 years did not provide evidence of a potential predisposition to IRS related to either FABP2 or MTP genotypes. However, we observed a heterogeneity of the FABP2 effect by IRS status on total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C), and apolipoprotein B (apoB) concentrations (P for interaction=0.045, 0.018, and 0.017, respectively). Among the metabolic components of IRS, only triglyceride (TG) displayed an interaction with FABP2 polymorphism: compared with Thr/Ala and Ala/Ala, the Thr/Thr genotype was associated with a steeper increase in TC, LDL-C, and apoB parallel to TG concentrations (P <0.001). IRS did not modify the associations between the MTP polymorphism and any of the biochemical parameters. Our study suggests that the effects of FABP2 allelic variations on lipid traits are context dependent, indicating that this variant may play an important role in cardiovascular pathogenesis in the presence of IRS or hypertriglyceridemia.

Genetic polymorphisms affecting the phenotypic expression of familial hypercholesterolemia

The clinical expression of heterozygous familial hypercholesterolemia (FH) is highly variable even in patients carrying the same LDL receptor (LDL-R) gene mutation. This variability might be due to environmental factors as well as to modifying genes affecting lipoprotein metabolism. We investigated Apo E (2, 3, 4), MTP (-493G/T), Apo B (-516C/T), Apo A-V (-1131T/C), HL (-514C/T and -250G/A), FABP-2 (A54T), LPL (D9N, N291S, S447X) and ABCA1 (R219K) polymorphisms in 221 unrelated FH index cases and 349 FH relatives with defined LDL-R gene mutations. We found a significant and independent effect of the following polymorphisms on: (i) plasma LDL-C (Apo E, MTP and Apo B); (ii) plasma HDL-C (HL, FABP-2 and LPL S447X); (iii) plasma triglycerides (Apo E and Apo A-V). In subjects with coronary artery disease (CAD+), the prevalence of FABP-2 54TT genotype was higher (16.5% versus 5.2%) and that of ABCA1 219RK and KK genotypes lower (33.0% versus 51.5%) than in subjects with no CAD. Independent predictors of increased risk of CAD were male sex, age, arterial hypertension, LDL-C level and FABP-2 54TT genotype, and of decreased risk the 219RK and KK genotypes of ABCA1. These findings show that several common genetic variants influence the lipid phenotype and the CAD risk in FH heterozygotes.

Postprandial lipemia in subjects with the threonine 54 variant of the fatty acid-binding protein 2 gene is dependent on the type of fat ingested

BACKGROUND

The alanine-for-threonine substitution at codon 54 (A54T polymorphism) in the fatty acid-binding protein 2 gene (FABP2) has been associated with hypertriglyceridemia and insulin resistance. Obese and diabetic T54 carriers have greater postprandial lipemia than do A54 homozygotes. The T54 protein isoform is also associated with increased triacylglycerol secretion in vitro.

OBJECTIVE

We investigated diet-gene interactions by measuring postprandial lipids, glucose, insulin, and C-peptide in healthy, nonobese A54 homozygotes and T54 carriers after ingestion of 3 different fats.

DESIGN

Eleven A54 homozygotes and 11 T54 carriers were given 3 oral-fat-tolerance tests (butter, safflower oil, and olive oil). Cholesterol and triacylglycerol were measured in plasma and in chylomicron fractions.

RESULTS

There was no main effect of FABP2 genotype for chylomicron triacylglycerol, glucose, or C-peptide. The area under the insulin curve and the ratio of insulin to C-peptide were lower in T54 carriers than in A54 homozygotes [312 +/- 29 ( +/- SEM) compared with 425 +/- 31 pmol. h/L (P = 0.05) and 0.23 +/- 0.03 compared with 0.40 +/- 0.05 (P = 0.04), respectively], which suggests greater hepatic insulin clearance in T54 carriers. An association between genotype and chylomicron cholesterol was seen only after olive oil: values were higher (P = 0.02) in T54 carriers (0.087 +/- 0.006 mmol. h/L) than in A54 homozygotes (0.058 +/- 0.004 mmol. h/L). The main effect of fat was significant for the areas under the chylomicron cholesterol and chylomicron triacylglycerol curves [higher values for safflower (0.635 +/- 0.053 and 2.48 +/- 0.30 mmol. h/L, respectively) and olive (0.592 +/- 0.052 and 2.48 +/- 0.32 mmol. h/L, respectively) oils than for butter (0.425 +/- 0.043 and 1.69 +/- 0.20 mmol. h/L, respectively); P < 0.05].

CONCLUSIONS

The A54T polymorphism results in a diet-gene interaction: the T54 group had increased chylomicron cholesterol after olive oil only. Nevertheless, the greater hepatic insulin clearance in T54 carriers suggests that the polymorphism may not be deleterious in nonobese subjects.

Whole genome scan for obstructive sleep apnea and obesity in African-American families

Obstructive sleep apnea (OSA) is a common, chronic disease associated with obesity. OSA and obesity are both prevalent in African Americans, who are also at increased risk for secondary complications. To identify susceptibility loci for OSA, we undertook a 9-centimorgans genome scan in 59 African-American pedigrees ascertained on the basis of either an affected individual with laboratory-confirmed disease or a proband who was a neighborhood control subject. Variance component linkage analysis was performed for the quantitative phenotypes apnea-hypopnea index (AHI) and body mass index. A candidate region on chromosome 8q (logarithm of odds [LOD] = 1.29, p = 0.006) gave the only evidence for linkage to the AHI. Body mass index was linked to multiple regions, most significantly to markers on chromosome 4q (LOD = 2.63, p = 0.0006) and 8q (LOD = 2.56, p = 0.0007). Evidence of linkage to the AHI was only slightly reduced after adjustment for body mass index. After adjustment for the AHI, some of the primary linkages to body mass index were greatly reduced whereas others remained suggestive. Our results suggest that there are both shared and unshared genetic factors underlying susceptibility to OSA and obesity, and that the genetic determinants of obesity in this population may be modulated by apnea severity.

Genetic risk for coronary artery disease in individuals with or without type 2 diabetes

Given that a substantial proportion of individuals with coronary artery disease (CAD) also have type 2 diabetes, it is important to identify genes that confer susceptibility to CAD independently in subjects with type 2 diabetes and in those without this condition. A large-scale association study was performed to identify genes that confer susceptibility to CAD in either the absence or presence of type 2 diabetes. The study population comprised 5207 unrelated Japanese individuals, including 3085 subjects with CAD and 2122 controls. Among all subjects, 1704 individuals had type 2 diabetes and 3503 individuals did not have this condition. The genotypes for 33 polymorphisms of 27 candidate genes were determined with a fluorescence- or colorimetry-based allele-specific DNA primer-probe assay system. Multivariate logistic regression analysis with adjustment for age, body mass index, and the prevalence of smoking, hypertension, hypercholesterolemia, and hyperuricemia revealed that the following polymorphisms were significantly (P < 0.005) associated with CAD: the 1019C -->T of the connexin 37 gene for men with type 2 diabetes; the 2445G -->A in the fatty acid-binding protein 2 gene for women with this condition; the -863C-->A in the tumor necrosis factor-alpha gene, the -219G-->T in the apolipoprotein E gene, the 1019C-->T in the connexin 37 gene for men without type 2 diabetes; and the -482C-->T in the apolipoprotein C-III gene for women without this condition. Genotyping of these polymorphisms may prove informative for assessment of the genetic risk for CAD in the absence or presence of type 2 diabetes.

The effect of polymorphism in the intestinal fatty acid-binding protein 2 gene on fat metabolism is associated with gender and obesity amongst non-diabetic Japanese-Americans

AIM

The role of the codon 54 polymorphism of the fatty acid-binding protein 2 (FABP2) gene on fat metabolism has been controversial. Assuming that the effects of the polymorphism were modulated by gender and obesity which were related to lipid and glucose metabolism, we investigated this polymorphism and its effect on fat metabolism according to such factors.

METHODS

Subjects were Japanese-Americans (123 men and 126 women) who were diagnosed as non-diabetic by a 75 g oral glucose tolerance test at the baseline.

RESULTS

During approximately 7.8 years, 49 (24 men and 25 women) were diagnosed with type 2 diabetes. In a Cox proportional hazards model, this polymorphism was not a significant variable in the incidence of diabetes in either gender. Amongst non-obese men with the Thr54 allele, there was a significant elevation of triglycerides (TGs) (p=0.033) compared with alanine (Ala) homozygotes. Women with the Thr54 allele had significantly elevated total cholesterol (p=0.033) and low-density lipoprotein-cholesterol (LDL-C) (p=0.023) compared with Ala54 homozygotes.

CONCLUSIONS

These results therefore suggested that the effects of the FABP2 polymorphism on TG, LDL-C and body mass index were associated with gender difference and obesity amongst non-diabetic Japanese-American subjects.