Investigation of Maternal Diet and FADS1 Polymorphism Associated with Long-Chain Polyunsaturated Fatty Acid Compositions in Human Milk.

Increasing the amount of long-chain polyunsaturated fatty acids (LCPUFA) in human milk is an important strategy for infant growth and development. We investigated the associations of LCPUFA compositions in human milk with maternal diet (especially fish and shellfish intake), with fatty acid Δ5 desaturase gene (FADS1) polymorphisms, and with gene-diet interactions. The present study was performed as part of an adjunct study of the Japan Environment and Children's Study. The participants were 304 lactating females, who provided human milk 6−7 months after delivery. Fatty acids in human milk were analyzed by gas chromatography, and dietary surveys were conducted using a brief self-administered diet history questionnaire. We also analyzed a single nucleotide polymorphism of FADS1 (rs174547, T/C). There was a significant difference in arachidonic acid (ARA) composition in human milk among the genotype groups, and the values were decreasing in the order of TT > TC > CC. The concentrations of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were also different between TT and CC genotype, indicating a tendency for decreasing values in the same order. The composition of ARA showed significant gene−dietary interactions in multiple regression analysis, and the positive correlation between fish and shellfish intake and ARA composition in human milk was significant only in the CC genotype. Moreover, the factor most strongly associated with EPA and DHA composition in human milk was fish and shellfish intake. Therefore, it was suggested that increasing fish and shellfish intake in mothers may increase EPA and DHA composition in human milk, while increasing fish and shellfish intake in CC genotype mothers may lead to increased ARA composition in human milk.

Associations of erythrocyte fatty acid compositions with FADS1 gene polymorphism in Japanese mothers and infants.

Long-chain polyunsaturated fatty acids (LC-PUFAs) are involved in the fetal growth in utero, and are essential for the development of visual and cognitive functions during infancy. The purpose of this study was to examine the associations of erythrocyte fatty acid compositions with FADS1 gene polymorphism in Japanese mothers and infants. The subjects were 383 mothers who participated in an adjunct birth cohort study of the Japan Environment and Children's Study (JECS). In maternal FADS1 SNP genotypes, the precursor fatty acids composition of the Δ5 desaturase in the maternal blood showed significant differences in levels among the groups, and showed increasing values in the order of TT < TC < CC genotype groups. On the other hand, many product fatty acids levels were significantly reduced in the order of TT > TC > CC genotype groups, and DHA levels were significantly lower in the CC genotype group relative to the other groups. Likewise, the relationship between fetal genotype group and fatty acid composition in cord blood was very similar to the maternal relationship. These results indicate the maternal and fetal blood fatty acid compositions are strongly influenced by the FADS1 genotypes. With respect to the cord blood DHA composition, the levels in the fetal CC genotype group showed a trend toward lower values in the maternal CC genotype group pair (p = 0.066) compared to the maternal TC genotype group pair. However, in the fetal TT and TC genotype groups (p = 0.131, p = 0.729, respectively), the maternal genotype did not have a significant effect. The DHA composition was more influenced by the maternal genotype in the fetal CC genotype group than in the fetal TT and TC genotype groups. It was shown that DHA transport via the placenta from the mother might be promoted in the fetal CC genotype compared to the other fetal genotype groups. In conclusion, differences in the FADS1 SNP genotypes of pregnant women and their children may greatly affect the supply of LC-PUFAs. Further studies on the involvement of the FADS1 polymorphisms and the fetal LC-PUFA levels in the fetal growth and development are warranted.

[Impact of visceral fat measurements and a weight loss support web system on visceral fat loss in a workplace setting: insights from a JVALUE2 (Japanese study of visceral adiposity and lifestyle information; utilization and evaluation)].

OBJECTIVES: Providing different programs of occupational health services in the same company is difficult. We report the results of a parallel randomized trial for the employees of our company for visceral fat measurements and the effect of a weight loss support web system. MATERIALS AND METHODS: 181 healthy employees with BMI over 23 who volunteered to participate in this study. In a parallel randomized study, we divided them into 3 groups (A, health guidance by occupational health staff with visceral fat measurements and a weight loss support web system; B, health guidance by occupational health staff with a weight loss support web system; C, without health guidance (control)) by date of birth. To assess the effects of guidance and support, we compared each group's waist circumference (WC), weight, and BMI, before and after the guidance. We also conducted questionnaire surveys of eating behavior and life activities before and after the guidance to estimate the relationship between the intervention method used for each group and their behavioral modification. RESULTS: 150 employees (83%) finished this program. Within 3 months, reduction in the outcome measures was largest in group A, and showed significant differences from the other two groups. For many employees in group A, eating behavior factors improved markedly; however, in the control group, there were no changes in eating behavior or daily living activities. CONCLUSIONS: A parallel randomized trial involving the employees of our company was performed and we scientifically verified the effects of an occupational health programs. Objective study of occupational health activities and measures were enabled by devising methods and procedures, e.g., applying the waiting-list method for the control group. This approach will lead to appropriate selection and precise implementation of evidence-based measures in occupational health in the future.

A novel acylaminoimidazole derivative, WN1316, alleviates disease progression via suppression of glial inflammation in ALS mouse model.

Amyotrophic lateral sclerosis (ALS) is an adult-onset motor neuron degenerative disease. Given that oxidative stress and resulting chronic neuronal inflammation are thought to be central pathogenic, anti-oxidative agents and modulators of neuronal inflammation could be potential therapies for ALS. We report here that the novel small molecular compound, 2-[mesityl(methyl)amino]-N-[4-(pyridin-2-yl)-1H-imidazol-2-yl] acetamide trihydrochloride (WN1316) selectively suppresses oxidative stress-induced cell death and neuronal inflammation in the late-stage ALS mice. WN1316 has high blood-brain-barrier permeability and water solubility, and boosts both neuronal apoptosis inhibitory protein (NAIP) and NF-E2-related factor 2 (Nrf2) which governed glutathione (GSH)-related anti-oxidation pathway protecting motor neurons against oxidative injuries. Post-onset oral administration of low dose (1-100 µg/kg/day) WN1316 in ALS(SOD1(H46R)) and ALS(SOD1(G93A)) mice resulted in sustained improved motor function and post onset survival rate. Immunohistochemical analysis revealed less DNA oxidative damage and motor neuronal inflammation as well as repression of both microgliosis and astrocytosis, concomitant down regulation of interleukin-1ß and inducible nitric oxide synthase, and preservation of the motoneurons in anterior horn of lumbar spinal cord and skeletal muscle (quadriceps femoris). Thus, WN1316 would be a novel therapeutic agent for ALS.

TRIB1 downregulates hepatic lipogenesis and glycogenesis via multiple molecular interactions.

Mammalian tribbles homolog 1 (TRIB1) regulates hepatic lipogenesis and is genetically associated with plasma triglyceride (TG) levels and cholesterol, but the molecular mechanisms remain obscure. We explored these mechanisms in mouse livers transfected with a TRIB1 overexpression, a shRNA template or a control (LacZ) adenovirus vector. The overexpression of TRIB1 reduced, whereas induction of the shRNA template increased, plasma glucose, TG, and cholesterol and simultaneously hepatic TG and glycogen levels. The involvement of TRIB1 in hepatic lipid accumulation was supported by the findings of a human SNP association study. A TRIB1 SNP, rs6982502, was identified in an enhancer sequence, modulated enhancer activity in reporter gene assays, and was significantly (P=9.39 × 10(-7)) associated with ultrasonographically diagnosed non-alcoholic fatty liver disease in a population of 5570 individuals. Transcriptome analyses of mouse livers revealed significant modulation of the gene sets involved in glycogenolysis and lipogenesis. Enforced TRIB1 expression abolished CCAAT/enhancer binding protein A (CEBPA), CEBPB, and MLXIPL proteins, whereas knockdown increased the protein level. Levels of TRIB1 expression simultaneously affected MKK4 (MAP2K4), MEK1 (MAP2K1), and ERK1/2 (MAPK1/3) protein levels and the phosphorylation of JNK, but not of ERK1/2. Pull-down and mammalian two-hybrid analyses revealed novel molecular interaction between TRIB1 and a hepatic lipogenic master regulator, MLXIPL. Co-expression of TRIB1 and CEBPA or MLXIPL reduced their protein levels and proteasome inhibitors attenuated the reduction. These data suggested that the modulation of TRIB1 expression affects hepatic lipogenesis and glycogenesis through multiple molecular interactions.

Seasonal effects of UCP1 gene polymorphism on visceral fat accumulation in Japanese adults.

Uncoupling protein 1 (UCP1) and ß3 adrenergic receptor (ADRB3) genes play central roles in the thermogenesis of brown adipose tissue (BAT) in adult humans. However, the importance of single-nucleotide polymorphisms (SNPs) in both genes during the development of obesity is controversial. Although active BAT in adult humans is frequently observed in the winter season, the effects of sampling season have not been taken into consideration in previous association studies. Here, we tested the associations of UCP1 -3826A/G and ADRB3 Trp64Arg with body mass index (BMI) and visceral fat area (VFA) in 3013 Japanese adults sampled during different seasons. Association between SNPs and the obesity-related traits were assessed using multiple linear regression models, including sex, age, physical activity, and genotypes. Both SNPs did not show significant associations in the models based on the entire cohort. However, in subsets comprising individuals mainly sampled from winter to spring, UCP1 showed significant associations with VFA (P = 0.0098) and VFA adjusted for BMI (P = 0.0128). Moreover, the effects of UCP1 on VFA were strongly negatively correlated with outdoor temperature (P = 0.00011), but not with night length (P = 0.039). ADRB3 did not show these associations, but an additive effect with UCP1 was observed for VFA adjusted for BMI (P = 0.0067). Subsets sampled in the hot season did not show significant associations for both SNPs. The season-specific effects of UCP1 on VFA were consistent with a previous finding that active BAT was more frequently found in winter than in summer, and supported the importance of cold stress in BAT activation and the significance of BAT in the development of obesity in adult humans.

Effects of Visceral Fat Accumulation Awareness on a Web-Based Weight-Loss Program: Japanese Study of Visceral Adiposity and Lifestyle Information-Utilization and Evaluation (J-VALUE).

A reduction of visceral fat is important for improvement of metabolic risk. This study was designed to compare the effects of a web-based program alone or together with measurement and self-awareness of accumulated visceral fat in Japanese workers. A new noninvasive device to measure visceral fat accumulation was introduced, and efficacy on weight-loss and improvement of healthy behaviors were examined. This study was conducted according to Helsinki declaration and approved by the ethical committee of Japan Hospital Organization, National Kyoto Hospital. Two-hundred and sixteen overweight and obese males with BMI of more than 23 participated from 8 healthcare offices of 3 Japanese private companies. Subjects were randomly allocated into control group, Web-based weight-loss program (Web), or Web + Visceral fat measurement group (Web + VFA). Eighty-one percent of participants completed the study. Reductions of body weight, waist circumference, and BMI were the largest in Web + VFA group, and the differences between groups were significant by ANOVA. Improvements of healthy behaviors were the largest in Web + VFA group, and the differences of healthy eating improvement scores between Web + VFA and control groups were significant. Our findings suggest that measurement and awareness of visceral fat are effective in weight reduction in overweight and obese males in the workplace.

Positive natural selection of TRIB2, a novel gene that influences visceral fat accumulation, in East Asia.

Accumulation of visceral fat increases cardiovascular mortality in industrialized societies. However, during the evolution of the modern human, visceral fat may have acted as energy storage facility to survive in times of famine. Therefore, past natural selection might contribute to shaping the variation of visceral fat accumulation in present populations. Here, we report that the gene encoding tribbles homolog 2 (TRIB2) influenced visceral fat accumulation and was operated by recent positive natural selection in East Asians. Our candidate gene association analysis on 11 metabolic traits of 5,810 East Asians revealed that rs1057001, a T/A transversion polymorphism in 3'untranslated region (UTR) of TRIB2, was strongly associated with visceral fat area (VFA) and waist circumference adjusted for body mass index (P = 2.7 × 10(-6) and P = 9.0 × 10(-6), respectively). rs1057001 was in absolute linkage disequilibrium with a conserved insertion-deletion polymorphism in the 3'UTR and was associated with allelic imbalance of TRIB2 transcript levels in adipose tissues. rs1057001 showed high degree of interpopulation variation of the allele frequency; the low-VFA-associated A allele was found with high frequencies in East Asians. Haplotypes containing the rs1057001 A allele exhibited a signature of a selective sweep, which may have occurred 16,546-27,827 years ago in East Asians. Given the predominance of the thrifty gene hypothesis, it is surprising that the apparently non-thrifty allele was selectively favored in the evolution of modern humans. Environmental/physiological factors other than famine would be needed to explain the non-neutral evolution of TRIB2 in East Asians.

A novel small molecule, N-(4-(2-pyridyl)(1,3-thiazol-2-yl))-2-(2,4,6-trimethylphenoxy) acetamide, selectively protects against oxidative stress-induced cell death by activating the Nrf2-ARE pathway: therapeutic implications for ALS.

Antioxidant defense is crucial in restoring cellular redox homeostasis. Recent findings have suggested that oxidative stress plays pivotal roles in the pathogenesis of many neurodegenerative diseases. Thus, an anti-oxidative stress remedy might be a promising means for the treatment of such disorders. In this study, we employed a novel ligand-based virtual screening system and identified a novel small molecule, N-(4-(2-pyridyl)(1,3-thiazol-2-yl))-2-(2,4,6-trimethylphenoxy) acetamide (CPN-9), which selectively suppressed oxidative stress-induced cell death in a cell-type-independent manner. CPN-9 upregulates NF-E2-related factor 2 (Nrf2), a key transcriptional regulator of the expression of phase II detoxification enzymes and antioxidant proteins, and Nrf2-regulated factors such as heme oxygenase-1 (HO-1), NAD(P)H quinone oxidoreductase 1 (NQO1), and glutamate-cysteine ligase modifier subunit (GCLM). The CPN-9-mediated upregulation of HO-1, NQO1, and GCLM was abolished by Nrf2 knockdown. Moreover, the antioxidant N-acetylcysteine reduced the protective effect of CPN-9 against oxidative stress-induced cell death with concomitant diminishing of Nrf2 nuclear translocation. These results indicate that CPN-9 exerts its activity via the reactive oxygen species-dependent activation of the Nrf2 signaling pathway in cultured cells. It is noteworthy that the postonset systemic administration of CPN-9 to a transgenic ALS mouse model carrying the H46R mutation in the human Cu/Zn superoxide dismutase (SOD1) gene sustained motor functions and delayed disease progression after onset. Collectively, CPN-9 is a novel Nrf2 activator and a neuroprotective candidate for the treatment of neurodegenerative diseases, including ALS.

High prevalence of an anti-hypertriglyceridemic variant of the MLXIPL gene in Central Asia.

MLXIPL is a transcription factor integral to the regulation of glycolysis and lipogenesis in the liver. Common variants of the MLXIPL gene (MLXIPL) are known to influence plasma triglyceride levels in people of European descent. As MLXIPL has a key role in energy storage, genetic variations of the MLXIPL may be relevant to physiological adaptations to nutritional stresses that have occurred during the evolution of modern humans. In the present study, we assessed the phenotypic consequences of the Q241H variant of MLXIPL in populations of Asian and Oceanian origin and also surveyed the prevalence of Q241H variant in populations worldwide. Multiple linear regression models based on 2373 individuals of Asian origin showed that the H allele was significantly associated with decreased concentrations of plasma triglycerides (P=0.0003). Direct genotyping of 1455 individuals from Africa, Asia and Oceania showed that the triglyceride-lowering H allele was found at quite low frequencies (0.00-0.16) in most of the populations examined. The exceptions were some Central Asian populations, including Mongolians, Tibetans and Uyghurs, which exhibited much higher frequencies of the H allele (0.21-0.26). The high prevalence of the H allele in Central Asia implies that the Q241H variant of MLXIPL might have been significant for utilization of carbohydrates and fats in the common ancestors of these populations, who successfully adapted to the environment of Central Asia by relying on nomadic livestock herding.

Bromocriptine methylate suppresses glial inflammation and moderates disease progression in a mouse model of amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disease characterized by a selective loss of upper and lower motor neurons. Since oxidative stress plays a crucial role in the progression of motor neuron loss observed in ALS, anti-oxidative agents could be an important therapeutic means for the ALS treatment. We have previously developed a drug screening system allowing the identification of small chemical compounds that upregulate endogenous neuronal apoptosis inhibitory protein (NAIP), an oxidative stress-induced cell death suppressor. Using this system, we identified the dopamine D2 receptor agonist bromocriptine (BRC) as one of NAIP-upregulating compounds. In this study, to prove the efficacy of BRC in ALS, we conducted a set of preclinical studies using a transgenic ALS mouse model carrying the H46R mutation in the human Cu/Zn superoxide dismutase (SOD1) gene ALS(SOD1(H46R)) by the post-onset administration of BRC. ALS(SOD1(H46R)) mice receiving BRC showed sustained motor functions and modest prolonged survival after onset. Further, BRC treatment delayed anterior horn cell loss, and reduced the number of reactive astrocytes and the level of inflammatory factors such as inducible nitric oxide synthase (iNOS) and tumor necrosis factor (TNF)-α in the spinal cord of late symptomatic mice. In vitro study showed the reduced level of extracellular TNF-α after lipopolysaccharide (LPS) exposure in BRC-treated mouse astrocytes. BRC-treated ALS(SOD1(H46R)) mice also showed a reduced level of oxidative damage in the spinal cord. Notably, BRC treatment resulted in an upregulation of anti-oxidative stress genes, activating transcription factor 3 (ATF3) and heme oxygenase-1 (HO-1), and the generation of a glutathione (GSH) in SH-SY5Y cultured neuronal cells in a dopamine receptor-independent manner. These results imply that BRC protects motor neurons from the oxidative injury via suppression of astrogliosis in the spinal cord of ALS(SOD1(H46R)) mice. Thus, BRC might be a promising therapeutic agent for the treatment of ALS.

A single nucleotide polymorphism in the FADS1/FADS2 gene is associated with plasma lipid profiles in two genetically similar Asian ethnic groups with distinctive differences in lifestyle.

Recent genome-wide association studies (GWASs) showed that single nucleotide polymorphisms (SNPs) in FADS1/FADS2 were associated with plasma lipid concentrations in populations with European ancestry. We investigated the associations between the SNPs in FADS1/FADS2 and plasma concentrations of triglycerides, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) in two Asian groups, i.e., Japanese and Mongolians. The genotype of rs174547 (T/C), found to be associated with triglyceride and HDL-C concentrations in the GWAS, was determined in 21,004 Japanese and 1,203 Mongolian individuals. Genotype-phenotype association was assessed by using multiple linear regression models, assuming an additive model of inheritance. The copy number of the rs174547 C allele was significantly associated with increased triglyceride levels (P = 1.5 x 10(-6)) and decreased HDL-C levels (P = 0.03) in the Japanese population. On the other hand, in the Mongolian population, the rs174547 C allele copy number was strongly associated with decreased LDL-C levels (P = 2.6 x 10(-6)), but was not associated with triglyceride and HDL-C levels. The linkage disequilibrium pattern and haplotype structures of SNPs around the FADS1/FADS2 locus showed no marked dissimilarity between Japanese and Mongolian individuals. The present data indicate that the FADS1/FADS2 locus can be added to the growing list of loci involved in polygenic dyslipidemia in Asians. Furthermore, the variable effects of FADS1/FADS2 on plasma lipid profiles in Asians may result from differences in the dietary intake of polyunsaturated fatty acids, which serve as substrates for enzymes encoded by FADS1/FADS2.

Regulatory SNP in the RBP4 gene modified the expression in adipocytes and associated with BMI.

Retinol-binding protein 4 (RBP4) is a recently identified adipokine that was involved in insulin resistance. RBP4 is predominantly expressed from the liver in normal metabolic state to transport retinoids throughout the body, but the exact physiological function and the regulatory mechanisms of adipocyte-derived RBP4 have not been revealed. We conducted the genetic analysis about metabolic parameters in Japanese and Mongolian; the minor allele carriers of regulatory single-nucleotide polymorphism (SNP -803G>A) showed significantly higher BMI in Japanese men (P = 0.009) and women (P = 0.017), and in Mongolian women (P = 0.009). Relative quantification of RBP4 transcripts in -803GA heterozygotes showed that the minor allele-linked haplotype-derived mRNA was significantly more abundant than the transcript from major allele. RBP4 promoter assay in 3T3L1 adipocytes revealed that the minor allele increased the promoter activity double to triple and the administration of 9-cis-retinoic acid (RA) and 8-bromo-cyclic adenosine monophosphate (8-Br-cAMP) enhanced the activity. Multiple alignment analysis of human, mouse, rat, and cattle RBP4 promoter suggested conserved seven transcription factor binding motifs. Electrophoretic mobility shift assay showed the -803G>A SNP modulate the affinity against unidentified DNA-binding factor, which was assumed to be a suppressive factor. These results collectively suggested that the minor allele of RBP4 regulatory SNP enhanced the expression in adipocytes, which may be associated with the adipogenesis.

Vitamin C activity of dehydroascorbic acid in humans--association between changes in the blood vitamin C concentration or urinary excretion after oral loading.

We performed oral loading of AsA or DAsA (1 mmol) in subjects who had consumed a diet low in vitamin C (C) (C< or =5 mg/d) for 3 d before loading, and measured urinary and blood vitamin C. Since the crossover method was used, the same experiment was repeated after an interval of about 1 mo in each subject. The results of the experiment including a total of 17 subjects for 2005 and 2006, were as follows. (1) There were marked individual differences in urinary C excretion. (2) The C level in 24-h urine after C loading did not differ between the two orally administered C forms (AsA and DAsA). (3) C excretion between 0 and 3 h after C loading was significantly higher (p<0.05) for the DAsA group, while those between 3 and 6, 6 and 9, 9 and 12, and 12 and 24 h after C loading were significantly higher (p<0.05 or p<0.01) for the AsA group. (4) The blood C concentration and the increase in C 1 h after C loading were significantly higher (p<0.05 and p<0.01, respectively) in the DAsA than in the AsA group. (5) Evaluation of the association between C metabolism and the single nucleotide polymorphisms of glutathione S-transferase P (GSTP) 1-1 showed a lower urinary C excretion and a significantly lower C level in 24-h urine (p<0.05) after AsA loading, and a significantly lower urinary C excretion between 0 and 3 h after DAsA loading (p<0.05) for the GA heterozygotes than for the AA homozygotes. Considering the activity of C as DAsA in humans, based on urinary and blood C levels after a single loading of C, the utilization of DAsA is equivalent to that of AsA, although the metabolic turnover time is different. The involvement of polymorphisms in the xenobiotic metabolizing enzyme, GSTP1-1, in C metabolism, particularly urinary C excretion, was also clarified. This demonstrates the necessity of considering gene polymorphisms in determining individual C requirements. An abstract of this paper was reported by the Vitamin C Research Committee (Ochanomizu University) in 2007.

A dopamine receptor antagonist L-745,870 suppresses microglia activation in spinal cord and mitigates the progression in ALS model mice.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by a selective loss of motor neurons in the motor cortex, brainstem, and spinal cord. It has been shown that oxidative stress plays a pivotal role in the progression of this motor neuron loss. We have previously reported that L-745,870, a dopamine D4 receptor antagonist, selectively inhibits oxidative stress-induced cell death in vitro and exerts a potent neuroprotective effect against ischemia-induced neural cell damage in gerbil. To investigate the efficacy of L-745,870 in the treatment of ALS, we here conducted a chronic administration of L-745,870 to transgenic mice expressing a mutated form of human superoxide dismutase gene (SOD1(H46R)); a mouse model of familial ALS, and assessed whether the mice benefit from this treatment. The pre-onset administration of L-745,870 significantly delayed the onset of motor deficits, slowed the disease progression, and extended a life span in transgenic mice. These animals showed a delayed loss of anterior horn cells in the spinal cord concomitant with a reduced level of microglial activation at a late symptomatic stage. Further, the post-onset administration of L-745,870 to the SOD1(H46R) transgenic mice remarkably slowed the disease progression and extended their life spans. Taken together, our findings in a rodent model of ALS may have implication that L-745,870 is a possible novel therapeutic means to the treatment of ALS.

Genetic polymorphisms of xenobiotic enzymes affect human vitamin C excretion.

This study describes the effect of gene polymorphisms on the metabolism of vitamin C. An oral loading of 1 mmol ascorbic acid (176 mg) or dehydroascorbic (174 mg) was given to 17 healthy females volunteers who had consumed a low vitamin C diet (vitamin C < 5 mg/day) for 3 days before loading. The urinary total vitamin C was determined. The urinary excretion of vitamin C (VC) was compared between ascorbic acid (AsA) and dehydroascorbic acid (DAsA), and the 24 hour total VC excretion was same. However gene polymorphisms of glutathione S-transferases P1 (GSTP1) showed the effect on that excretion. GSTP1 is one of xenobiotic enzymes in VC metabolism. The VC excretions in 24 hour after VC loading were greater (P < .01) in AA homozygotes of GSTP1 (46.7 +/- 18.1 mg) than GA heterozygotes (28.2 +/- 14.0 mg). On the single oral administration, the type of polymorphisms of GSTP1 has stronger effect on VC metabolism than the form of VC, DAsA and AsA. This study showed that determination of nutrient requirement needs to be considered with personal genotype.

Comparative study of polymorphisms on genes associated with lifestyle related diseases in Asian and Pacific populations.

An increase in prevalence of lifestyle related diseases becomes one of the main threats to human health in Asia-Pacific regions. Especially Pacific countries face the marked epidemic of obesity and related disorders. Understanding of the genetic basis for these diseases is awaited. We investigated frequencies of 106 single nucleotide polymorphisms (SNPs) in genes associated with lifestyle related diseases in 1,878 individuals from five Asia-Pacific countries including Japan, China, Mongolia, Thailand, and Palau. Population genetic analyses revealed that disease susceptible variants of SNPs in TRIB3, PTGS2, ADIPOR1, DGAT1, UCP2, FOXC2, and ESR1 were overrepresented in the Palau population in comparison with the Asian populations. These gene variants likely contribute to the high prevalence of obesity and related diseases in Pacific populations. The present results would be helpful in coping with the lifestyle related diseases and may provide a new insight into the human dispersal in Asia-Pacific regions.

Diversity in genes responsible for lifestyle-related diseases in Asia-Pacific region.

In Asia-Pacific countries, both environmental modernization and hereditary traits of Mongoloid reported to cause rapid increase in lifestyle-related diseases (LRD). However, reproducibility of reported responsive-factors is low. To examine this, a decision-tree method of complexity-model was applied to select LRD-responsive-factors. Genomic DNA was collected from Asia-Pacific regions. Single nucleotide polymorphisms (SNPs) on genomic DNA were determined as hereditary-trait-factor. Three indices of LRD (BMI, body fat, and serum leptin levels) were classified according to published criteria. WEKA Machine-learning system was used as decision-tree software. Age was added as a factor with different dimension. Selected factors were validated by other statistical methods. In Thai-males, GLUT) (glucose-transporter 1)-SNP was most-responsive to body fat, followed by USF1-SNP (transcription-factor for lipid metabolism). Differences between genotypes were validated (P = .002 for GLUT1 by Levene's, P = .071 for USF1 by ANOVA). Responsive-factors of Thai-females, Palau-males and Palau-females, were consisted with SNPs and age, and varied by groups. Convincing responsive-factors were not selected from mixed-data. Decision-tree-analysis successfully selected the convincing results. Responsive-factors differed by ethnic group and gender.

Polymorphism of glutathione S-transferase P1 gene affects human vitamin C metabolism.

There are large inter-individual differences in the metabolism of vitamin C (VC), which is composed of both ascorbic acid (AsA) and dehydroascorbic acid (DAsA). AsA is oxidized to DAsA in a series of xenobiotic reactions. Thus, the effects of polymorphism A313G (Ile105Val) in the gene for glutathione S-transferases P1 (GSTP1), one of the most active xenobiotic enzymes, on human VC metabolism were studied. The variant frequency of GSTP1 among the present subjects (n=210) was AA 71.0%; GA 27.0% and GG 1.9%. At 24 h after administration of 1 mmol of VC to young women (n=17; age, 21.0+/-1.1 y), total VC excretion (46.7+/-18.1mg) by AA homozygotes of GSTP1 was greater (p<0.0069) than that (28.2+/-14.0 mg) by GA heterozygotes. One hour after administration of VC, blood total VC levels were also significantly different (p<0.0036) between the homozygotes and heterozygotes. The effects of other polymorphisms in xenobiotic enzymes on VC metabolism were small.

Identification of a regulatory SNP in the retinol binding protein 4 gene associated with type 2 diabetes in Mongolia.

Increased levels of retinol binding protein 4 (RBP4) in serum is associated with insulin resistance. To examine this further, the genomic region of RBP4 was genetically surveyed in Mongolian people, who as a group are suffering from a recent rapid increase in diabetes. The RBP4 gene was screened by DHPLC system, and the PCR fragments which showed heteroduplex peaks in multiple samples were followed by direct sequencing to identify common polymorphisms in 48 Mongolian diabetic samples. Identified single nucleotide polymorphisms (SNPs) were genotyped in 511 control and 281 type 2 diabetes samples. The functions of SNPs in the regulatory region were assessed by reporter gene assay and electrophoretic mobility shift assay. Possible association between functional SNPs and serum RBP4 levels or metabolic parameters was statistically assessed. Nine SNPs were identified in the RBP4 gene. A case-control study revealed that the rare alleles of four SNPs were associated with increased risk of diabetes, even after Bonferroni correction (-803, G > A, P = 0.0054; +5169, C > T, P = 0.0025; +6969, G > C, P = 0.0015; +7542, T > del, P = 0.0015). The -803 G > A SNP influenced the transcription efficiency in a hepatocarcinoma cell line as well as the binding efficiency of hepatocyte nuclear factor 1 alpha to the motif. In addition, the -803 A allele was associated with increased serum RBP4 levels in diabetic patients. We have identified a functional SNP in the RBP4 gene associated with type 2 diabetes in Mongolian people.