Hypertension genes are genetic markers for insulin sensitivity and resistance

Association of αENaC p. Ala663Thr Gene Polymorphism With Sudden Sensorineural Hearing Loss

Objective: The etiology of sudden sensorineural hearing loss (SSNHL) is still unknown. It has been demonstrated that normal endolymph metabolism is essential for inner ear function and that epithelial sodium channels (ENaC) may play an important role in the regulation of endolymphatic Na⁺. This study aimed to explore the potential association between αENaC p. Ala663Thr gene polymorphism and SSNHL. Methods: Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to examine the genotype and allele frequency of the αENaC p. Ala663Thr polymorphism in 20 cases of low-frequency SSNHL (LF-SSNHL), 19 cases of high-frequency SSNHL (HF-SSNHL), 31 cases of all frequency SSNHL (AF-SSNHL), 42 cases of profound deafness SSNHL (PD-SSNHL), and 115 normal controls. Results: The T663 allele was found to be significantly associated with an increased risk of LF-SSNHL (p = 0.046, OR = 2.16, 95% CI = 1.01-4.62). The TT genotype and T663 allele, on the other hand, conferred a protective effect for PD-SSNHL (AA vs. TT: p = 0.012, OR = 0.25, 95% CI = 0.08-0.74; A vs. T: p = 0.001, OR = 0.36, 95% CI = 0.21-0.61). However, there was no statistically significant difference in genotype or allele frequency between the two groups (HF-SSNHL and AF-SSNHL) and the control group. Conclusion: The αENaC p. Ala663Thr gene polymorphism plays different roles in different types of SSNHL.

The antihypertensive effect of irbesartan in spontaneously hypertensive rats is associated with improvement of the leptin-adiponectin imbalance

OBJECTIVE

This study aimed to investigate whether the antihypertensive effect of irbesartan (IRB) in spontaneously hypertensive rats (SHR) was achieved through improvement of insulin resistance and adjustment of the LPN-APN imbalance.

METHODS

SHR rats were divided into SHAM, SHR-A and SHR-I group(8 per group). Homologous Wistar-Kyoto (WKY) rats were used as control group (WKY).The SHR-I group received 30 mg/kg/d IRB, the SHR-A group received 2.5 mg/kg AML. After 8 weeks, systolic blood pressure (SBP) was measured. The concentrations of blood glucose, insulin, LPN and APN were detected. Rat epididymal adipose tissues were collected to analyze the mRNA expression levels ofepididymal LPN and APN using reverse transcription-polymerase chain reaction. In addition, the LPN/APN ratio was calculated. Results:SBP, homeostasis model assessment of insulin resistance (HOMA-IR), LPN concentration, adipose LPN mRNA expression level, and the LPN/APN ratio increased (P<0.05) and APN concentration and adipose APN mRNA expression level decreased (P<0.05) in SHR rats.IRB decreased SBP, HOMA-IR, serum LPN, adipose LPN mRNA expression, and the LPN/APN ratio and increased serum APN and adipose APN mRNA expression.

CONCLUSION

The antihypertensive effect of IRB in SHR rats was associated with its improvement of insulin resistance and correction of the LPN-APN imbalance. Abbreviations: ANOVA, one-way analysis of variance; SHR, Spontaneously hypertensive rats; WKY, Wistar kyoto rats; IRB, Irbesartan; AML, Amlodipine; LPN, Leptin; APN, Adiponectin; Ang-II, AngiotensinⅡ; HOMA-IR, Homoeostasis model assessment-insulin resistance; SBP, Systolic blood pressure; RT-PCR, Reverse transcription polymerase chain reaction; ARB, AngiotensinⅡreceptor blocker.

Glu298Asp (rs1799983) Polymorphism Influences Postprandial Vascular Reactivity and the Insulin Response to Meals of Varying Fat Composition in Postmenopausal Women: Findings from the Randomized, Controlled Dietary Intervention and VAScular function (DIVAS)-2 Study

BACKGROUND

Previous acute studies suggest the Glu298Asp polymorphism (rs1799983) may influence vascular reactivity in response to long-chain n-3 PUFA intake. However, the effects of this genotype on postprandial vascular function after meals rich in SFAs, n-6 PUFAs, and MUFAs are unclear.

OBJECTIVES

This study determined the impact of the Glu298Asp polymorphism on changes in vascular function and cardiometabolic risk biomarkers in response to sequential meals of varying fat composition.

METHODS

In a randomized, double-blind, crossover, acute study, 32 postmenopausal women (mean ± SD age: 58 ± 5 y; BMI: 25.9 ± 4.1 kg/m2) consumed mixed meals (breakfast: 0 min, 50 g fat; lunch: 330 min, 30 g fat) containing SFAs, n-6 PUFAs, or MUFAs on 3 occasions. Blood samples for cardiometabolic disease risk markers and real-time measures of vascular reactivity [including flow-mediated dilatation (FMD; primary outcome)] were collected/performed before and regularly for 480 min after breakfast. Participants were retrospectively genotyped for the Glu298Asp (rs1799983) polymorphism. Data were analyzed using linear mixed models.

RESULTS

For the postprandial %FMD response, a test fat × genotype interaction was observed for the AUC (P = 0.019) but not incremental AUC (IAUC), with the AUC being ∼24% greater after MUFA- than after SFA- and n-6 PUFA-rich meals in the Glu298 homozygotes (P ≤ 0.026). Test fat × genotype interactions were also evident for postprandial insulin (P ≤ 0.005), with the MUFA-rich meals demonstrating significantly higher AUC (12.8%/14.9%), IAUC (14.6%/20.0%), and maximum concentration (20.0%/34.5%) than the SFA- and n-6 PUFA-rich meals, respectively, in Asp298 carriers (P < 0.05). Genotype did not influence other study outcome measures in response to the test fats.

CONCLUSIONS

Our findings suggest the Glu298Asp polymorphism may represent a potential determinant of the inter-individual variability in postprandial responsiveness of %FMD and insulin to acute meal fat composition in postmenopausal women. Further studies are required to confirm these observations.This trial was registered at clinicaltrials.gov as NCT02144454.

Systematic Understanding of the Mechanisms of Flos Chrysanthemi Indici-mediated Effects on Hypertension via Computational Target Fishing

AIMS AND OBJECTIVE

Hypertension-induced stroke and coronary artery disease are significant causes of global morbidity and mortality. Metabolic hypertension has recently become the leading cause of hypertension. Flos Chrysanthemi Indici (CIF) has a long history as a treatment of hypertension as part of traditional Chinese medicine. However, its mechanisms of activity remain largely unknown. This study was aimed to uncover the potential anti-hypertensive mechanisms of CIF based on network pharmacology.

MATERIALS AND METHODS

In this research, a systems pharmacology approach integrating the measurement of active compounds, target fishing, gene screening, Gene Ontology (GO) pathway analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) Orthology Based Annotation System (KOBAS) database analysis, and compound-target network construction were performed to explore the anti-hypertensive mechanisms of CIF.

RESULTS

These studies revealed that 12 bioactive compounds in CIF had good druggability, 5 of which were flavonoids. After screening, 8 of those 12 bioactive compounds interacted with 118 hypertensionrelated target genes, which were mapped to 218 signal pathways. Network analysis showed that these targets were associated with improving insulin resistance, improving vascular function, inhibiting renninangiotensin- aldosterone system (RAAS), inhibiting the sympathetic nervous system (SNS) and regulating other physiological processes.

CONCLUSION

In summary, CIF is predicted to target multiple proteins and pathways to form a network that exerts systematic pharmacological effects in order to regulate blood pressure and metabolic disorder.

Association of endothelial nitric oxide synthase (eNOS) and norepinephrine transporter (NET) genes polymorphism with type 2 diabetes mellitus

Genetic factors in combination with environmental factors play a critical role in the development type 2 diabetes mellitus (T2DM) which is growing as an epidemic globally. In present study we aim to assess the association of eNOS (G894T, rs1799983) and NET (G1287A, rs5569) genes polymorphism with T2DM. A case-control study including a total of 400 North Indian subjects (200 T2DM cases and 200 controls) was performed using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) approach to analyze genetic polymorphism. Alleles/genotype frequencies between cases and controls were compared using χ² and Student's t-tests. Odds ratios and 95% confidence intervals were calculated by logistic regression to assess the relative association between disease and genotypes. In case of NET gene, GG (P = 0.002 in T2DM males, 0.053 in overall T2DM cases) genotype and G allele (P = 0.003 in T2DM males, 0.027 in overall T2DM cases) were found to be a positive risk factors and AG genotype (P = 0.012 in T2DM males) and A allele (P = 0.003 in T2DM males, P = 0.027 in overall T2DM cases) as negative risk factor for T2DM. No association of eNOS gene polymorphism was found with T2DM (P values of all genotypes and alleles were greater than 0.05). NET gene polymorphism might be associated with the risk of T2DM whereas; eNOS gene polymorphism do not confer any risk of T2DM in North Indian Ethnic group. It is hoped that understanding genetic causes of T2DM will lead to earlier diagnosis, preventive measures and more effective and specific treatment.

The contribution of phosphodiesterases to cardiac dysfunction in rats with metabolic syndrome induced by a high-carbohydrate diet

Metabolic syndrome (MetS) is a cluster of risk factors, including insulin resistance among others, underlying the development of diabetes and (or) cardiovascular diseases. Studies show a close relationship between cardiac dysfunction and abnormal cAMP catabolism, which contributes to pathological remodelling. Stimulating the synthesis of cAMP via suppression of phosphodiesterases (PDEs) has positive therapeutic effects. Therefore, we examined the role of PDEs on cardiac dysfunction in high-carbohydrate diet-induced MetS rats. We first demonstrated significantly high expression levels of PDE3 and PDE4, the most highly expressed subtypes, together with depressed cAMP levels in heart tissue from MetS rats. Second, we demonstrated the activity of these PDEs by using either their basal or PDE inhibitor-induced intracellular levels of cAMP and Ca²⁺, the transient intracellular Ca²⁺ changes under electrical stimulation, isometric contractions in papillary muscle strips and some key signalling proteins (such as RyR2, PLN, PP1A, and PKA) are responsible for the Ca²⁺ homeostasis in isolated cardiomyocytes from MetS rats. The clear recovery in decreased basal cAMP levels, increased protein expression levels of PDE3 and PDE4, and positive responses in the altered Ca²⁺ homeostasis to PDE inhibitors as seen in our study can provide important insights about the roles of activated PDEs in depressed contractile activity in hearts from MetS rats.

Sex differences in the metabolic effects of the renin-angiotensin system

Obesity is a global epidemic that greatly increases risk for developing cardiovascular disease and type II diabetes. Sex differences in the obese phenotype are well established in experimental animal models and clinical populations. While having higher adiposity and obesity prevalence, females are generally protected from obesity-related metabolic and cardiovascular complications. This protection is, at least in part, attributed to sex differences in metabolic effects of hormonal mediators such as the renin-angiotensin system (RAS). Previous literature has predominantly focused on the vasoconstrictor arm of the RAS and shown that, in contrast to male rodent models of obesity and diabetes, females are protected from metabolic and cardiovascular derangements produced by angiotensinogen, renin, and angiotensin II. A vasodilator arm of the RAS has more recently emerged which includes angiotensin-(1-7), angiotensin-converting enzyme 2 (ACE2), mas receptors, and alamandine. While accumulating evidence suggests that activation of components of this counter-regulatory axis produces positive effects on glucose homeostasis, lipid metabolism, and energy balance in male animal models, female comparison studies and clinical data related to metabolic outcomes are lacking. This review will summarize current knowledge of sex differences in metabolic effects of the RAS, focusing on interactions with gonadal hormones and potential clinical implications.

The Role of Genetic Polymorphism in the Formation of Arterial Hypertension, Type 2 Diabetes and their Comorbidity

BACKGROUND

Hereditary component plays a significant role in the formation of insulin resistance (IR) - one of the pathogenetic links of arterial hypertension (AH) and type 2 diabetes mellitus (DM2). However, the genetic predisposition to IR can not be realized and does not manifest itself clinically in the absence of appropriate factors of the environment (excessive nutrition, low physical activity, etc.).

OBJECTIVE

The review summarizes the results of studies which describe the contribution of genetic polymorphism to the formation and progression of AH, DM2 and their comorbidity in various populations.

RESULTS

In many studies, it has been established that genetic polymorphism of candidate genes is influenced by the formation, course and complication of AH and DM2. According to research data, the modulating effect of polymorphism of some genetic markers of AH and DM2 on metabolism and hemodynamics has been established. The results of numerous studies have shown a higher frequency of occurrence of AH and DM2, as well as their more severe course with adverse genetic polymorphisms. At the same time, the role of genetic polymorphism in the formation of AH and DM2 differs in different populations.

CONCLUSION

Contradictory data on the influence of gene polymorphisms on the formation of AH and DM2 in different populations, as well as a small number of studies on the combined effects of several polymorphisms on the formation of comorbidity, determine the continuation of research in this direction.

Endothelial nitric oxide synthase gene polymorphisms and erectile dysfunction in chronic pain

OBJECTIVES

To investigate whether endothelial nitric oxide synthase (eNOS) T786C, 4VNTR and G894 T gene polymorphisms could mediate in andrological treatment response in Spaniards.

SUBJECT PATIENTS/METHODS

The study participants were Spaniard males with erectile dysfunction (ED) and chronic pain (n = 105) recruited at the Pain Unit. eNOS polymorphisms were genotyped by quantitative polymerase chain reaction using Taqman specific probes. Statistical analyses were carried out using R-3.2.4 software.

RESULTS

A total of 69 patients required andrological treatment and 76% of them improved ED upon iPED5 (20%), testosterone (35%) or iPDE5/testosterone treatment (45%); being significantly better in T786C-CC patients. Multivariate regression analysis indicated that age, opioid daily dose and carriage of T786C-C allele influenced the risk and ED severity in Spaniard chronic pain patients.

CONCLUSION

T786C polymorphism at eNOS locus appeared to be a major contributor in the variable erectile function iPDE5/testosterone response in Spaniards.

Investigation of potential genomic biomarkers for obesity and personalized medicine

Obesity, as a global health issue, is a complex metabolic syndrome and its association with many chronic diseases. The pathology of obesity results from an interaction of psychological, environmental and variety of genetic factors. Etiologic determinants and molecular pathophysiology of obesity have not yet understood clearly. Previously shown that genetic markers have a significant role in the development of obesity, although results are divergent with populations. Turkish Cypriots have a unique mixture of allele distributions as being a small-islander population. Therefore, the current study was aimed to evaluate the association between obesity and three putative obesity-related ADIPOQ, FTO and ACE gene markers, respectively. We investigated a possible association of ADIPOQ rs2241766 G>T, FTO rs9939609 A>T and ACE rs4340288 DIP variants among obese and non-obese Turkish Cypriot origin. Additionally, the correlation between these variants and biochemical and physical measurements were also evaluated to determine the possible biomarker for obesity in the population. Only FTO rs9939609 A>T polymorphism was associated with obesity and no association was observed with ADIPOQ rs2441666 G>T and ACE rs4340288 DIP. To conclude, FTO rs9939609 A allele found to have strong association with obesity in the population of Turkish Cypriots.

Genetic variants conferring susceptibility to gastroschisis: a phenomenon restricted to the interaction with the environment?

BACKGROUND

Genes involved in gastroschisis have shown a strong interaction with environmental factors. However, less is known about its influence. We aimed to systematically review the genetic associations of gastroschisis, to summarize whether its genetic susceptibility has been restricted to the interaction with the environment, and to identify significant gaps that remain for consideration in future studies.

METHODS

Genetic association studies of gastroschisis published 1980-2017 (PubMed/MEDLINE) were independently searched by two reviewers. Significant SNP-gastroschisis associations were grouped into crude and stratified risks, whereas SNPs were assessed from two or more independent studies. Frequencies, odds ratios, and 95% confidence intervals were pooled using descriptive analysis and Chi-square test accounting for heterogeneity.

RESULTS

Seven eligible articles capturing associations of 14 SNPs from 10 genes for crude risk (including 10 and 4 SNPs with increased and decreased risk, respectively) and 30 SNPs from 14 genes for stratified risk in gastroschisis (including 37 and 14 SNPs with increased and decreased risk, respectively) were identified (Fisher's exact test, P = 0.438). The rs4961 (ADD1), rs5443 (GNB3), rs1042713, and rs1042714 (ADRB2) were significantly associated with gastroschisis.

CONCLUSIONS

Genetic susceptibility in gastroschisis is not restricted to the interaction with the environment and should not be too narrowly focused on environmental factors. We found significant associations with four SNPs from three genes related to blood pressure regulation, which supports a significant role of vascular disruption in the pathogenesis of gastroschisis. Future studies considering gene-gene or gene-environmental interactions are warranted for better understanding the etiology of gastroschisis.

Gene variants as risk factors for gastroschisis

In a population‐based case‐control study in California of 228 infants, we investigated 75 genetic variants in 20 genes and risk of gastroschisis with regard to maternal age, race/ethnicity, vitamin use, and smoking exposure. We hypothesized that genes related to vascular compromise may interact with environmental factors to affect the risk of gastroschisis. Haplotypes were constructed for 75 gene variants using the HaploView program. Risk for gastroschisis associated with each gene variant was calculated for both the homozygotes and the heterozygotes, with the homozygous wildtypes as the referent. Risks were estimated as odds ratios (ORs) with 95% confidence intervals (CIs) by logistic regression. We found 11 gene variants with increased risk and four variants with decreased risk of gastroschisis for heterozygous (OR_h) or homozygous variants (OR_v) genotypes. These included NOS3 (rs1036145) OR_h = 0.4 (95% CI: 0.2–0.7); NOS3 (rs10277237) OR_v = 2.7 (95% CI: 1.3–6.0); ADD1 (rs12503220) OR_h = 2.9 (95% CI: 1.6–5.4), GNB3 (rs5443) OR_h = 0.2 (95% CI: 0.1–0.5), OR_v = 0.4 (95% CI: 0.2–0.9); ICAM1 (rs281428) OR_v = 6.9 (95% CI: 2.1–22.9), ICAM1 (rs3093030) OR_v = 2.6 (95% CI: 1.2–5.6); ICAM4 (rs281438) OR_v = 4.9 (95% CI: 1.4–16.6), ICAM5 (rs281417) OR_h = 2.1 (95% CI: 1.1–4.1), OR_v = 4.8 (95% CI: 1.7–13.6); ICAM5 (rs281440) OR_h = 23.7 (95% CI: 5.5–102.5), OR_v = 20.6 (95% CI: 3.4–124.3); ICAM5 (rs2075741) OR_v = 2.2 (95% CI: 1.1–4.4); NAT1 OR_v = 0.3 (95% CI: 0.1–0.9). There were additional associations between several gene variants and gastroschisis among women aged 20–24 and among mothers with and without vitamin use. NOS3, ADD1, ICAM1, ICAM4, and ICAM5 warrant further investigation in additional populations and with the interaction of additional environmental exposures. © 2016 Wiley Periodicals, Inc.

The characteristics of pre-diabetic patients associated with body composition and cardiovascular disease risk factors in the Iranian population

Background:

Different populations have shown various patterns of association between impaired fasting glucose (IFG) and body composition parameters and risk factors of cardiovascular disease (CVD). The current study aimed at investigating the differences between persons with prediabetes and healthy people in terms of CVD risk factors including body composition parameters, blood pressure, and lipid profile in a sample of the Iranian population.

Materials and Methods:

In a case-control setting, a sample containing 386 (193 prediabetic subjects and 193 normal subjects) of the first-degree relatives of diabetic patients aged 35-55 years were investigated. Samples were assessed using glucose tolerance categories. Prediabetes was defined according to the American Diabetes Association (ADA) criteria. Body composition parameters, blood pressure, glucose parameters, and lipid profile were measured and compared between the two groups.

Results:

Prediabetic patients had higher body mass index (BMI), waist circumference (WC), and body fat (BF) in comparison to the control group (P < 0.05). In addition, prediabetic subject had a higher intake of energy, carbohydrate, protein, fat, and cholesterol and it seems that these patients had an unhealthy dietary intake (P < 0.05). Fasting blood glucose (FBG) (P < 0.001), total cholesterol (P = 0.007), low-density lipoprotein cholesterol (LDL-C), and triglyceride (P = 0.021) were higher in prediabetic patients (P < 0.05) than in the controls.

Conclusion:

Both the risk factors of CVD and body composition parameters were different between the prediabetic and normal groups; total cholesterol (TC), triglyceride (TG), and FBS were predictors of the risk of prediabetes.

Risk given by AGT polymorphisms in inducing susceptibility to essential hypertension among isolated populations from a remote region of China: A case-control study among the isolated populations

INTRODUCTION

Hypertension is a serious risk factor affecting up to 30% of the world's population with a heritability of more than 30-50%. The aim of this study was to investigate the contribution of the polymorphisms localized in the angiotensinogen (AGT) gene, a main component of the renin-angiotensin-aldosterone system, in inducing the susceptibility to essential hypertension (EH) among isolated populations (Yi and Hani minorities) with low prevalence rate from the remote region of Yunnan in China.

METHODS

A case-control association study was performed, and all subjects were genotyped for the seven single nucleotide polymorphisms localized in the AGT region by polymerase chain reaction-restriction fragment length polymorphism analysis.

RESULTS

Three polymorphisms, i.e. rs5046, rs5049, and rs2478544, were significantly associated with EH among the Hani minority. The associations, found in the Yi minority, did not reach a conclusive level of statistical significance. The polymorphisms of rs2478544 and rs5046 caused the transformations of exonic splicing enhancer sites and transcription factor binding sites, respectively, in the bioinformatic analyses. The haplotype-rs5046T, rs5049A, rs11568020G, rs3789679C, rs2478544C was susceptible for EH among the Hani minority.

CONCLUSION

Our findings suggested that the AGT polymorphisms have played a vital role in determining an individual's susceptibility to EH among the isolated population, which would be helpful for EH management in the remote mountainous region of Yunnan in China.

The AGT and the GNB3 polymorphisms and insulin resistance in prehypertension

OBJECTIVE

This study surveyed the frequencies of single nucleotide polymorphisms (SNPs) M235T AGT and C825T GNB3, and their association with insulin resistance, other biochemical markers and qualitative variables in subjects with high normal blood pressure and/or prehypertension in the Greek population.

DESIGN

330 men and women of Greek origin were divided into 3 groups: a) hypertensive, b) prehypertensive and c) control group. These groups were genetically tested for these polymorphisms and insulin resistance with the HOMA index.

RESULTS

No statistically significant differences were found among the polymorphisms of the compared groups. However, the ? allele carriers (CT/TT vs. CC) of the C825T polymorphism were associated with an increased BMI in all 3 groups (p=0.004). The HOMA index was higher in the hypertensive (p=0.006) and prehypertensive (p=0.016) versus the control group, and similar results were found for insulin (hypertensive vs. control p=0.012, prehypertensive vs. control p=0.001) without statistical significance between the first 2 groups (p=0.522). Additionally, there was a statistically significant difference between the control group and the hypertensive and prehypertensive groups regarding cholesterol (control vs. hypertensive p=0.001, control vs. prehypertension p=0.018) and triglycerides (control vs. hypertensive p=0.0001, control vs. prehypertension p=0.007). Differences were also noted between the control and the hypertensive group regarding the value of HDL (p=0.005) and LDL (p=0.013).

CONCLUSION

This study failed to demonstrate a correlation between specific SNPs, blood pressure and insulin resistance in the 3 groups. However, T allele carriers of the polymorphism C825T were found to have an increased BMI. Similarly, increased insulin resistance and lipidemia were more common in the hypertensive and prehypertensive populations.

QTLs influencing IGF-1 levels in a LOU/CxFischer 344F2 rat population. Tracks towards the metabolic theory of Ageing

OBJECTIVE

Since a reduction of the insulin/IGF-1 signaling cascade extends life span in many species and IGF-1 signaling might partly mediate the effects of caloric restriction (CR), an experimental intervention for increasing longevity, the purpose of the present study was to use quantitative trait loci (QTL) analysis, an unbiased genetic approach, to identify particular regions of the genome influencing plasma IGF-1 levels in an F2 intercross between F344 and LOU/C rats; the latter being an inbred strain of Wistar origin, considered as a model of healthy aging since it resists to age (and diet)-induced obesity.

DESIGN

F1 hybrids were obtained by crossbreeding LOU/C with F344 rats, and then F1 were bred inter se to obtain the F2 population, of which 93 males and 94 females were studied. Total plasma IGF-1 levels were determined by radioimmunoassay. A genome scan of the F2 population was made with 100 microsatellite markers) selected for their polymorphism between LOU/C and F344 strains (and by covering evenly the whole genome.

RESULTS

By simple interval mapping sex-dependent QTLs were found on chromosome 17 in males and on chromosome 18 in females. By multiple interval mapping, additional QTLs were found on chromosomes 1, 4, 5, 6, 12, 15 and 19 in males and on chromosomes 3, 5, 6, 12 and 17 in females. Only the markers D1Rat196 and D12Mgh5 were found in both males and females. The majority of QTLs corresponded to metabolic syndrome (cardiac function: n = 45 (30%), obesity/diabetes: n = 22 (15%), inflammation: n = 19 (13%) and only a limited number to body weight: n = 13 (9%), proliferation (n = 10 (7%) or ossification: n = 7 (5%). Ninety-six candidate genes were located on the different QTLs. A significant proportion of these genes are connected to IGF-1 production and receptor pathways (n = 18) or metabolic syndrome (n = 11).

CONCLUSIONS

Subsequent studies are necessary to determine whether the genetic networks underscored are also involved in age-associated obesity, diabetes and inflammation as well as cardiovascular impairments.

The renin angiotensin aldosterone system and insulin resistance in humans

Alterations in the renin angiotensin aldosterone system (RAAS) contribute to the underlying pathophysiology of insulin resistance in humans; however, individual differences in the treatment response of insulin resistance to RAAS blockade persist. Thus, understanding inter-individual differences in the relationship between the RAAS and insulin resistance may provide insights into improved personalized treatments and improved outcomes. The effects of the systemic RAAS on blood pressure regulation and glucose metabolism have been studied extensively; however, recent discoveries on the influence of local tissue RAAS in the skeletal muscle, heart, vasculature, adipocytes, and pancreas have led to an improved understanding of how activated tissue RAAS influences the development of insulin resistance and diabetes in humans. Angiotensin II (ANGII) is the predominant RAAS component contributing to insulin resistance; however, other players such as aldosterone, renin, and ACE2 are also involved. This review examines the role of local ANGII activity on insulin resistance development in skeletal muscle, adipocytes, and pancreas, followed by a discussion of the other RAAS components implicated in insulin resistance, including ACE2, Ang1-7, renin, and aldosterone.

Metabonomics study of essential hypertension and its chinese medicine subtypes by using gas chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy

A metabonomic study was performed to investigate the metabolic mechanism of essential hypertension and its Chinese medicine subtypes, including “Yin-deficiency and Yang-hyperactivity syndrome” (YDYHS) and “Yin-Yang deficiency syndrome” (YYDS). Plasma samples from 22 healthy volunteers, 31 hypertensive patients with YDYHS, and 29 hypertensive patients with YYDS were analyzed by ¹H-NMR spectroscopy and gas chromatography coupled with mass spectrometry (GC-MS). The three groups were distinctly classified by principal components analysis (PCA) and partial least squares discriminant analysis (PLS-DA). According to identified biomarkers and their related pathways, abnormal glucose metabolism might be the main common pathway from YDYHS to YYDS, and sympathetic nervous system activation would play an important role in the pathogenesis of YDYHS, while a low metabolic rate usually occurred in YYDS.

Atherogenic indices and prehypertension in obese and non-obese children

We evaluate the relationship between different lipoproteins and atherogenic indices with pre-hypertension in 297 obese and 942 non-obese children with Tanner stage 1 enrolled in a multicentre, community-based cross-sectional study. Height, weight, fasting glucose and insulin levels, total cholesterol, triglycerides, high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), non-HDL-c, LDL/HDL-c, triglycerides/cholesterol and total cholesterol/HDL-c ratios were measured. Mean age was 8.4 ± 1.2 years; pre-hypertension was identified in 104 (8.4%) participants, 46 (15.5%) obese and 58 (6.1%) non-obese children. The pre-hypertensive non-obese children show a high proportion of family history of hypertension (41.6 and 24.7%, p = 0.002) and elevation of insulin at a relatively low body mass index. The triglycerides:HDL-c ratio, but not other lipoproteins or atherogenic indices, was associated with pre-hypertension in obese (1.15, 95% confidence intervals 1.06-1.26) and non-obese children (1.38 95% confidence intervals 1.22-1.57). The triglycerides:HDL-c ratio is related to pre-hypertension in children; the family history of hypertension seems to be a risk factor in developing pre-hypertension.

Endothelin Type A Receptor Genotype is a Determinant of Quantitative Traits of Metabolic Syndrome in Asian Hypertensive Families: A SAPPHIRe Study

Co-heritability of hypertension and insulin resistance (IR) within families not only implies genetic susceptibility may be responsible for these complex traits but also suggests a rational that biological candidate genes for hypertension may serve as markers for features of the metabolic syndrome (MetS). Thus we determined whether the T323C polymorphism (rs5333) of endothelin type A (ETA) receptor, a predominant receptor evoking potent vasoconstrictive action of endothelin-1, contributes to susceptibility to IR-associated hypertension in 1694 subjects of Chinese and Japanese origins. Blood pressures (BPs) and biochemistries were measured. Fasting insulin level, insulin-resistance homeostasis model assessment (HOMAIR) score, and area under curve of insulin concentration (AUCINS) were selected for assessing insulin sensitivity. Genotypes were obtained by methods of polymerase chain reaction-restriction fragment length polymorphism. Foremost findings were that minor allele frequency of the T323C polymorphism was noticeable lower in our overall Asian subjects compared to multi-national population reported in gene database; moreover both the genotypic and allelic frequencies of the polymorphism were significantly different between the two ethnic groups we studied. The genotype distributions at TT/TC/CC were 65, 31, 4% in Chinese and 51, 41, 8% in Japanese, respectively (p < 0.0001). Additionally, carriers of the C homozygote revealed characteristics of IR, namely significantly higher levels of fasting insulin, HOMAIR score, and AUCINS at 29.3, 35.3, and 39.3%, respectively, when compared to their counterparts with TT/TC genotypes in Chinese. Meanwhile, the CC genotype was associated with a higher level of high density lipoprotein cholesterol in Japanese. No association of the polymorphism with BP was observed. This study demonstrated for the first time that T323C polymorphism of ETA receptor gene was associated with an adverse insulin response in Chinese and a favorite atherogenic index in Japanese.

Association of endothelial nitric oxide synthase gene polymorphisms with classical risk factors in development of premature coronary artery disease

Genetic polymorphism of the endothelial nitric oxide synthase (eNOS) affects the pathogenesis of atherosclerosis and associated with premature coronary artery disease (PCAD). We aimed to explore the association between Glu298Asp polymorphism of the eNOS gene and premature CAD in Egyptians, and the possible interaction between this polymorphism and other risk factors. The study population consisted of 116 patients with PCAD, and 119 controls. Glu298Asp polymorphism (rs1799983) of the eNOS gene was analyzed by polymerase chain reaction (PCR). We found that the TT genotype of the eNOS gene increased the risk of PCAD by 2.6. Hypertension, diabetes, smoking, total cholesterol, triglycerides, LDLc, HDLc and TT genotype of the eNOS gene were independent risk factors for the development of PCAD. We conclude that, the TT genotype of Glu298Asp polymorphism of eNOS gene is an independent risk factor of PCAD in Egyptians. The association of smoking, obesity, dyslipidemia and/or metabolic syndrome with the TT genotype increased the risk of the development of PCAD.

The association of the angiotensinogen gene with insulin sensitivity in humans: a tagging single nucleotide polymorphism and haplotype approach

The purpose of this study was to clarify the association of the angiotensinogen gene (AGT) with insulin sensitivity using single nucleotide polymorphism (SNP) and haplotype analyses in a white cohort. A candidate gene association study was conducted in white persons with and without hypertension (N = 449). Seventeen SNPs of the AGT gene and their haplotypes were analyzed for an association with homeostasis model assessment of insulin resistance (HOMA-IR). Multivariate regression model accounting for age, sex, body mass index, hypertension status, study site, and sibling relatedness was used to test the hypothesis. Nine of the 17 SNPs were significantly associated with lower HOMA-IR levels. Homozygous minor allele carriers of the most significant SNP, rs2493134 (GG), a surrogate for the gain-of-function mutation rs699 (AGT p.M268T), had significantly lower HOMA-IR levels (P = .0001) than heterozygous or homozygous major allele carriers (AG, AA). Direct genotyping of rs699 in a subset of the population showed similar results, with minor allele carriers exhibiting significantly decreased HOMA-IR levels (P = .003). Haplotype analysis demonstrated that haplotypes rs2493137A|rs5050A|rs3789678G|rs2493134A and rs2004776G|rs11122576A|rs699T|rs6687360G were also significantly associated with HOMA-IR (P = .0009, P = .02), and these results were driven by rs2493134 and rs699. This study confirms an association between the AGT gene and insulin sensitivity in white humans. Haplotype analysis extends this finding and implicates SNPs rs2493134 and rs699 as the most influential. Thus, AGT gene variants, previously shown to be associated with AGT levels, are also associated with insulin sensitivity; suggesting a relationship between the AGT gene, AGT levels, and insulin sensitivity in humans.

Insertion/deletion polymorphism of angiotensin-1 converting enzyme is associated with metabolic syndrome in Hungarian adults

The aim of our study was to evaluate whether any association exists between metabolic syndrome (MS) and ACE I/D and AGT M235T gene polymorphisms in Hungarians as an example of European Caucasian population. Study subjects of our cross-sectional study were recruited from the Hungarian General Practitioners’ Morbidity Sentinel Stations Program. The study population ( n = 1762) approximates very well the age and sex distribution of the general Hungarian population. MS was defined according to the latest diagnostic criteria proposed by the International Diabetes Federation. The frequency of DD genotype (31.36% vs. 25.42%, p = 0.006) and the frequency of D allele (0.56 vs. 0.51, p = 0.006) were significantly higher in the metabolic group than in the non-metabolic group. The distribution of the AGT M235T polymorphism was similar in each group investigated. Association was shown in the case of patients in whom central obesity was combined with elevated TG and low HDL cholesterol level ( p = 0.024 and p = 0.022). It suggests that ACE I/D polymorphism is likely to be involved in lipid metabolism.

Familial burden of hypertension and its effect on blood pressure levels, insulin resistance, and intracellular ions in Greek offspring

We examined the effect of familial burden of hypertension on blood pressure (BP) levels, insulin resistance (IR), and intracellular ions in healthy offspring of Greek families with one, two, or no hypertensive parents. A total of 118 adolescents and young adults were recruited. Three groups were formed: Group A, both parents were normotensive (N-N); Group B, one parent normotensive and one hypertensive (N-H); and Group C, both parents hypertensive (H-H). BP levels, homeostasis assessment model-IR (HOMA-IR) index, and intracellular Na(+), K(+), Ca(2+), and Mg(2+) were compared in the three groups. Also, multiple regression analyses were used to create models with BP parameters and HOMA-IR as dependent variables. Offspring of H-H parents had higher body mass index (BMI) (mean difference, 4.3 +/- 0.9 kg/m(2); 95% confidence interval [CI], 2.0-6.5), higher systolic blood pressure (SBP) (mean difference, 13.2 +/- 3.1 mm Hg; 95% CI, 5.8-20.7), increased levels of intraerythrocyte Ca(2+) (mean difference, 0.02 +/- 0.01 mmol/l; 95% CI, 0.05-0.1), and fasting blood glucose (mean difference, 0.31 +/- 0.10 mmol/l; 95% CI, 0.05-0.56) when compared with those with no parental history of hypertension. In the regression model, SBP was found to be significantly affected by BMI (beta = 0.43; P < .001), iK(+) (beta = -0.224; P < .01), and gender (beta = -0.298; P < .001). The addition of the parental history showed a significant independent association of H-H parental history with SBP (beta = 0.27; P < .05). HOMA-IR was significantly determined by BMI (beta = 0.511; P < .05), iNa(+) (beta = 0.211; P < .05), and iMg(2+) (beta = -0.205; P < .05). Parental history of hypertension did not influence the HOMA-IR index. This study highlights the relative importance and contribution of environmental and genetic influences on the development of high BP. Both these influences possibly alter the intracellular ionic environment. However, nurture rather than familial hypertension burden is the key factor of IR in Greek offspring.

The characteristics of impaired fasting glucose associated with obesity and dyslipidaemia in a Chinese population

BACKGROUND

Different populations have diverse patterns of relationships between Impaired Fasting Glucose (IFG) and obesity and lipid markers, it is important to investigate the characteristics of associations between IFG and other related risk factors including body mass index (BMI), waist circumstance (WC), serum lipids and blood pressure (BP) in a Chinese population.

METHODS

This was a case-control study of 648 IFG subjects and 1,296 controls derived from a large-scale, community-based, cross-sectional survey of 10,867 participants. Each subject received a face-to-face interview, physical examination, and blood tests, including fasting blood glucose and lipids. Student's t-test, Chi-square test, Spearman correlation and multiple logistic regressions were used for the statistical analyses.

RESULTS

Fasting plasma glucose (FPG) was positively correlated with BMI, WC, systolic blood pressure (SBP), diastolic blood pressure (DBP), triglyceride (TG), and total cholesterol (TC), and was negatively correlated with high density lipoprotein-cholesterol (HDL-C) (all p < 0.05). BMI was more strongly correlated with IFG than with WC. The correlation coefficient of FPG was remarkably higher with TG (0.244) than with TC (0.134) and HDL-C (-0.192). TG was an important predictor of IFG, with odds ratios of 1.76 (95%CI: 1.31-2.36) for subjects with borderline high TG level (1.70 mmol/l < or = TG < 2.26 mmol/l) and 3.13 (95% CI: 2.50-3.91) for those with higher TG level (TG > or = 2.26 mmol/l), when comparing to subjects with TG < 1.70 mmol/l. There was a significant dose-response relationship between the number of abnormal variables and increased risk of IFG.

CONCLUSIONS

In this Chinese population, both BMI and WC were important predictors of IFG. Abnormal TG as a lipid marker was more strongly associated with IFG than were TC and HDL-C. These factors should be taken into consideration simultaneously for prevention of IFG.

Reactive oxygen species-mediated effects on vascular remodeling induced by human atrial natriuretic peptide T2238C molecular variant in endothelial cells in vitro

OBJECTIVES

T2238C ANP (atrial natriuretic peptide) gene variant has been associated with increased cardiovascular risk in humans and with a significant pharmacogenomic effect on cardiovascular disease outcome in hypertensive patients. We investigated the impact of T2238C ANP gene variant on oxidative stress production, cell proliferation and migration, angiogenesis and vascular remodeling in human umbilical vein endothelial cells in vitro.

METHODS

Differentially expressed genes in human umbilical vein endothelial cells exposed to either wild-type (TT2238) or mutant (CC2238) alpha-ANP were characterized by real time-PCR-macroarray analysis using human oxidative stress, angiogenesis and matrix arrays. Reactive oxygen species (ROS) production was determined by dihydroethidium and by evaluation of dichlorofluorescein content. NADPH oxidase gp91phox subunit was investigated by western blotting. Endothelial cell proliferation, migration and tube formation were characterized both in the presence and in the absence of NADPH oxidase inhibition.

RESULTS

Compared with TT2238, CC2238 alpha-ANP altered the redox state balance of the cells in a more significant manner, favoring ROS production and reducing antioxidative stress response. Gene expression of molecules involved in atherogenesis and vascular remodeling was enhanced. In contrast to TT2238 peptide, CC2238 was unable to stimulate cell proliferation and it markedly inhibited endothelial cell tube formation. NADPH oxidase inhibition restored the cell proliferative properties under CC2238 peptide exposure.

CONCLUSION

CC2238 alpha-ANP led to ROS accumulation and increased expression of genes related to atherosclerosis and vascular remodeling in human umbilical vein endothelial cells. As a consequence of NADPH-derived ROS, blunted endothelial cell proliferation and impaired endothelial cell tube formation were observed. These in-vitro effects may link the T2238C alpha-ANP variant to enhanced susceptibility to vascular damage in vivo.

Association of genetic variants with the metabolic syndrome in 20,806 white women: The Women's Health Genome Study

BACKGROUND

Candidate genes associated with cardiovascular disease (CVD) represent potential risk factors for the metabolic syndrome (MetS).

METHODS

The association between prevalent MetS and a panel of 62 polymorphisms within 42 candidate genes, previously implicated in the pathophysiology of CVD, were investigated in 20,806 white participants of the Women's Health Study. All were free of known CVD and diabetes at baseline. Logistic regression was performed to investigate the relationship between genotype and the MetS assuming an additive model. Stratified analyses by hormone therapy use were also performed. Correction for multiple testing was performed using false discovery rate for polymorphisms and false positive rate probability for stratified analysis, respectively.

RESULTS

The prevalence of the MetS was 23%. In a marker-by-marker analysis, the ADRB2 rs180088 (OR 1.22, 95% CI 1.01-1.48) and PAI1 rs1799768 (OR 1.05, 95% CI 1.01-1.10) were associated with an increased MetS risk, whereas the C5 rs17611 (OR 0.95, 95% CI 0.91-1.00) and the CTLA4 rs5742909 (OR 0.91, 95% CI 0.84-0.99) were associated with a decreased risk. In postmenopausal women, an increased MetS risk was found for the ADRB2 rs180088 (OR 1.28, 95% CI 0.99-1.65), PAI1 rs1799768 (OR 1.07, 95% CI 1.01-1.14), SCNN1A rs5742912 (OR 1.22, 95% CI 1.01-1.47), and IL1A rs1800587 (OR 1.07, 95% CI 1.01-1.15), whereas the AGTR1 rs5186 (OR 0.93, 95% CI 0.87-0.99) was associated with decreased risk. However, none remained significant after false discovery rate correction. In a stratified analysis, one or more copies of the variant C allele of SCNN1A rs5742912 were associated with an increased MetS risk among the current users (OR 1.56, 95% CI 1.21-2.01, P interaction .007, false positive rate probability 0.13).

CONCLUSIONS

Effect modification of the SCNN1A rs5742912 on the MetS by hormone therapy use warrants further investigation.

Hypertension and the cardiometabolic syndrome in Chile: a review of concepts and consequences for the developing world

We review some recent developments regarding the concept of cardiometabolic syndrome and its relation with hypertension and overall cardiovascular disease risk. We emphasize how this new clinical entity has helped to understand multimorbidity in chronic diseases. This concept has important consequences for individual patient treatment as well as public health policy. The challenge derived from cardiovascular disease and other chronic conditions is increasing worldwide, but the highest burden is located in the developing world. Thus, new and cost-effective approaches are needed for diseases that are mainly occurring in the poorest and less educated populations. We illustrate this situation analyzing hypertension and cardiometabolic syndrome data derived from a recent national health survey in Chile.

Endothelial nitric oxide synthase (eNOS) gene polymorphisms and their association with type 2 diabetes-related traits in Mexican Americans

Genetic variants of the endothelial nitric oxide synthase (eNOS) gene such as T-786C, Glu298Asp and 27bp-VNTR have been examined for their association with type 2 diabetes (T2DM)-related traits in various populations but not in Mexican Americans. However, the results from such studies have been controversial. This study investigated whether these three polymorphisms are associated with T2DM and its related traits in Mexican Americans, a population at high risk for T2DM and its complications. The study participants (n=670; 39 families) were genotyped for the three polymorphisms using polymerase chain reaction followed by restriction fragment length polymorphism assay. Association analyses between these polymorphisms and T2DM and its related phenotypes were carried out using a measured genotype approach as implemented in the computer program SOLAR. Of the variants examined, only the 27bp-VNTR variant exhibited significant association with high-density lipoprotein cholesterol (HDL-C) (p=0.04) and diastolic blood pressure (DBP) levels (p=0.02) after accounting for trait-specific covariates. The carriers of the rare allele (27bp-VNTR-4a) were found to have decreased HDL-C and increased DBP levels. In conclusion, of the genetic polymorphisms examined at the eNOS locus, only 27bp-VNTR appears to be a minor contributor to the variation in T2DM-related traits in Mexican Americans.

Effects of interacting networks of cardiovascular risk genes on the risk of type 2 diabetes mellitus (the CODAM study)

BACKGROUND

Genetic dissection of complex diseases requires innovative approaches for identification of disease-predisposing genes. A well-known example of a human complex disease with a strong genetic component is Type 2 Diabetes Mellitus (T2DM).

METHODS

We genotyped normal-glucose-tolerant subjects (NGT; n = 54), subjects with an impaired glucose metabolism (IGM; n = 111) and T2DM (n = 142) subjects, in an assay (designed by Roche Molecular Systems) for detection of 68 polymorphisms in 36 cardiovascular risk genes. Using the single-locus logistic regression and the so-called haplotype entropy, we explored the possibility that (1) common pathways underlie development of T2DM and cardiovascular disease -which would imply enrichment of cardiovascular risk polymorphisms in "pre-diabetic" (IGM) and diabetic (T2DM) populations- and (2) that gene-gene interactions are relevant for the effects of risk polymorphisms.

RESULTS

In single-locus analyses, we showed suggestive association with disturbed glucose metabolism (i.e. subjects who were either IGM or had T2DM), or with T2DM only. Moreover, in the haplotype entropy analysis, we identified a total of 14 pairs of polymorphisms (with a false discovery rate of 0.125) that may confer risk of disturbed glucose metabolism, or T2DM only, as members of interacting networks of genes. We substantiated gene-gene interactions by showing that these interacting networks can indeed identify potential "disease-predisposing allele-combinations".

CONCLUSION

Gene-gene interactions of cardiovascular risk polymorphisms can be detected in prediabetes and T2DM, supporting the hypothesis that common pathways may underlie development of T2DM and cardiovascular disease. Thus, a specific set of risk polymorphisms, when simultaneously present, increases the risk of disease and hence is indeed relevant in the transfer of risk.

Association of alpha-adducin Gly460Trp polymorphism with coronary artery disease in a Korean population

OBJECTIVE

Coronary artery disease is caused by multiple genetic and environmental factors. The disease is also closely associated with cardiovascular conditions such as hypertension. In order to investigate any possible role of hypertension candidate genes in the disease development and progression, we examined the association of the polymorphisms of 31 hypertension candidate genes with coronary artery disease.

METHODS

Genetic polymorphisms of 31 hypertension candidate genes were initially screened by resequencing DNA samples from 24 unrelated individuals in a Korean population. Association analysis was performed using 1284 unrelated Korean men, including 749 coronary artery disease subjects and 535 normal healthy controls.

RESULTS

We identified a total of 409 single nucleotide polymorphisms including 40 nonsynonymous single nucleotide polymorphisms, 32 insertions/deletions and four microsatellites. Among 40 nonsynonymous single nucleotide polymorphisms, 29 were examined for an association with coronary artery disease. A significant association with coronary artery disease was observed in a polymorphism of the ADD1 gene (Gly460Trp; +29017G/T) (odds ratio 0.71-0.81; P = 0.01-0.04). The same polymorphism was also associated with the number of arteries with significant coronary artery stenosis in the coronary artery disease patients (P = 0.01) as well as the increase in systolic blood pressure (P = 0.02).

CONCLUSIONS

The ADD1 Gly460Trp polymorphism is significantly associated with an increased risk of coronary artery disease as well as blood pressure, indicating that ADD1 plays a role in the pathogenesis of coronary artery disease as well as hypertension.

Influence of ScaI and Natriuretic Peptide (NP) Clearance Receptor Polymorphisms of the NP System on NP Concentration in Chronic Heart Failure

Background: Genetic variants related to the natriuretic peptide (NP) system [ScaI mutated allele (A1) of the atrial NP (ANP) gene and the C variant of the natriuretic peptide clearance receptor (NPRC) gene] have been identified as independent risk factors for cardiovascular morbidity and mortality. Despite the importance of NPs in heart failure (HF), the role of these polymorphisms in HF has not been evaluated.

Methods: We screened 124 HF patients [mean (SD), age 66 (12) years, 100 men, ejection fraction 32% (10%), New York Heart Association (NYHA) class I–II 65, III–IV 59] for NP concentrations [ANP, brain NP (BNP) and amino-terminal pro-BNP (NT-proBNP)] and for the ScaI and NPRC variants.

Results: ScaI polymorphism had no effect on NP concentration in the NYHA I–II subgroup. Conversely, in severe HF, A1 carriers had higher ANP (P ≤0.05), BNP (P &lt;0.01), and NT-proBNP (P &lt;0.01) than A2A2 patients. After multivariate adjustment, A1 presence remained an independent predictor for increased NP. Regarding NPRC polymorphism in mild HF, higher ANP (P &lt;0.05) and BNP (P &lt;0.05) were observed in CC than A allele carriers. After multivariate adjustment, however, this association did not remain significant. In severe HF, the NPRC polymorphism had no effect on NP.

Conclusions: The ScaI polymorphism of the ANP gene might be an important additive genetic factor influencing neurohormonal activation and disease progression in severe HF. The NPRC polymorphism is not an independent determinant of NP concentration in HF.

Genome-wide scan for blood pressure in Australian and Dutch subjects suggests linkage at 5P, 14Q, and 17P

Large-scale studies estimate the heritability of blood pressure at approximately 50%. We carried out a genome-wide linkage analysis to search for chromosomal loci that might explain this heritability using longitudinal, multiple measures of systolic and diastolic blood pressure obtained in sibling pairs and dizygotic twin pairs from 2 countries (a total of 286 pairs from Australia and 636 pairs from the Netherlands). These pairs and a large number of their parents were genotyped with microsatellite markers. Multivariate linkage analysis of the combined data of both countries, using a variance components approach, showed suggestive linkage for diastolic blood pressure on chromosomes 5p13.1 (logarithm of odds score: 2.48), 14q12 (logarithm of odds score: 2.40) and 17q24.3 (logarithm of odds score: 2.36). The highest logarithm of odds score of 1.21 for systolic blood pressure was observed on chromosome 13q34. These results replicate earlier findings and add to a slowly emerging picture of multiple loci contributing to quantitative blood pressure variation.

High dietary sucrose triggers hyperinsulinemia, increases myocardial β-oxidation, reduces glycolytic flux and delays post-ischemic contractile recovery

Although the causal relationship between insulin resistance (IR) and hypertension is not fully resolved, the importance of IR in cardiovascular dysfunction is recognized. As IR may follow excess sucrose or fructose diet, the aim of this study was to test whether dietary starch substitution with sucrose results in myocardial dysfunction in energy substrate utilization and contractility during normoxic and post-ischemic conditions. Forty-eight male Wistar rats were randomly allocated to three diets, differing only in their starch to sucrose (S) ratio (13, 2 and 0 for the Low S, Middle S and High S groups, respectively), for 3 weeks. Developed pressure and rate x pressure product (RPP) were determined in Langendorff mode-perfused hearts. After 30 min stabilization, hearts were subjected to 25 min of total normothermic global ischemia, followed by 45-min reperfusion. Oxygen consumption, beta-oxidation rate (using 1-13C hexanoate and Isotopic Ratio Mass Spectrometry of CO2 produced in the coronary effluent) and flux of non-oxidative glycolysis were also evaluated. Although fasting plasma glucose levels were not affected by increased dietary sucrose, high sucrose intake resulted in increased plasma insulin levels, without significant rise in plasma triglyceride and free fatty acid concentrations. Sucrose-rich diet reduced pre-ischemic baseline measures of heart rate, RPP and non-oxidative glycolysis. During reperfusion, post-ischemic recovery of RPP was impaired in the Middle S and High S groups, as compared to Low S, mainly due to delayed recovery of developed pressure, which by 45 min of reperfusion eventually resumed levels matching Low S. At the start of reperfusion, delayed post-ischemic recovery of contractile function was accompanied by: (i) reduced lactate production; (ii) decreased lactate to pyruvate ratio; (iii) increased beta-oxidation; and (iv) depressed metabolic efficiency. In conclusion, sucrose rich-diet increased plasma insulin levels, in intact rat, and increased cardiac beta-oxidation and coronary flow-rate, but reduced glycolytic flux and contractility during normoxic baseline function of isolated perfused hearts. Sucrose rich-diet impaired early post-ischemic recovery of isolated heart cardiac mechanical function and further augmented cardiac beta-oxidation but reduced glycolytic and lactate flux.

Angiotensinogen gene polymorphism (Met235Thr) influences visceral obesity and insulin resistance in obese Japanese women

To investigate the relationship between angiotensinogen (AGT) Met235Thr polymorphism (M235T) and human obesity, because AGT is regarded as one of the cytokines produced from adipocytes and serum AGT concentrations are reported to be positively correlated with body mass index. One hundred and twenty obese Japanese women (age, 58.8+/-9.4 years; body mass index, 32.2+/-4.9 kg/m(2)) were enrolled. Angiotensinogen genotypes were determined with a fluorescent allele-specific DNA primer assay system. Subjects were divided into M/M, M/T, and T/T groups. Control subjects comprised 146 healthy age-matched women. Clinical characteristics and the effects of diet and exercise therapy for 6 months were compared among the 3 genotypes. The genotype frequencies of AGT M235T polymorphism were in accordance with the Hardy-Weinberg equation (obese: M/M, 6.7%; M/T, 27.5%; T/T, 65.8%; control: M/M, 6.8%; M/T, 21.2%; T/T, 71.9%). The frequency of the T allele did not differ between obese and control subjects (0.80 vs 0.83). As the number of obese women with M/M genotype was only 8, comparisons of the characteristics and outcomes of weight reduction therapy were performed only between subjects with M/T genotype and T/T genotype. In the T/T group, % body fat and waist circumference at baseline were significantly greater than in the M/T group (36.3%+/-4.8% vs 33.8%+/-4.7%, P=.0105; 107.9+/-10.9 vs 102.6+/-7.9 cm, P=.0428, respectively). Before the weight reduction therapy, significantly higher insulin and higher homeostasis model assessment (HOMA-R) were demonstrated in the T/T group than in the M/T group (9.1+/-5.5 microU/mL vs 5.9+/-4.4 microU/mL, P=.0056; 2.3+/-1.4 vs 1.6+/-1.3, P=.0252, respectively). Both systolic and diastolic blood pressure at baseline in the T/T group tended to be higher than those in the M/T group, but the differences were not significant. No genotype-dependent difference in energy expenditure or outcome of weight reduction therapy was observed with respect to AGT M235T polymorphism. After the diet and exercise therapy, the blood pressure in the T/T group tended to be higher than that in the M/T group, but the difference was not significant. We demonstrated that the T/T genotype of the AGT M235T gene polymorphism was positively related to visceral obesity and hyperinsulinemia in obese Japanese women. Blood pressure did not show genotype-specific differences before or after the treatment. Further studies of the association between obesity and this gene polymorphism should contribute to understanding and treating obesity-related diseases.

Associations between RAS Gene Polymorphisms, Environmental Factors and Hypertension in Mongolian People

OBJECTIVE

To explore the association between RAS system genes (AGT, ACE and AT(1)R) polymorphisms, environmental factors and hypertension in Mongolian people.

METHODS

On the basis of cross-sectional study, a case-control study with 299 hypertensives and 281 nomotensives was conducted, and the conditions of environmental factors were acquired by questionnaire. Serum lipid and insulin were detected by using biochemical experiments. Six single nucleotide polymorphisms of RAS system were genotyped by polymerase chain reaction/restriction fragment length polymorphism and polymerase chain reaction/single strand conformation polymorphism.

RESULTS

Overweight or obesity, high serum TG and insulin resistance were risk factors of hypertension by single factor analysis. All the RAS genotype distributions were compatible with Hardy-Weinberg expectations. There were no significant differences to be found between cases and controls for genotype frequencies or allele frequencies of the six polymorphisms of RAS system, except in men group, OR value of men carried ACE ID+DD genotype vs. men carried II genotype was 2.20 (95%CI 1.21-4.02), and OR of people who carried both ACE ID (or DD) and AGT M235T MT (or MM) vs. people with both ACE ID (or DD) and AGT M235T TT was 1.59 (95%CI 1.06-2.38).

CONCLUSIONS

Overweight or obesity, dyslipidemia and insulin resistance were risk factors of hypertension in Mongolian people. ACE gene ID+DD genotype was the risk factor of hypertension in men group. People who carried both ACE ID (or DD) and AGT M235T MT (or MM) had more risk to have hypertension.

Selected gene polymorphisms and their interaction with maternal smoking, as risk factors for gastroschisis

BACKGROUND

Gastroschisis is a severe birth defect in which the infant is born with a portion of the intestines extruding through a small tear in the abdominal wall, usually to the right of the umbilical cord. Its etiology is unknown, but the prevailing hypothesis is that it results from a vascular accident at the time of involution of the right umbilical vein or of the development of the superior mesenteric artery.

METHODS

In a case-control study of 57 cases of gastroschisis and 506 controls, we tested DNA for polymorphisms of 32 genes representing enzymes involved in angiogenesis, blood vessel integrity, inflammation, wound repair, and dermal or epidermal strength.

RESULTS

In logistic regression, controlling for maternal ethnicity, and using the homozygote wild-type as referent, the following gene polymorphisms were associated with an increased risk for a gastroschisis for heterozygotes: ICAM1 gly241arg (odds ratio [OR], 1.9; 95% confidence interval [CI], 1.1 -3.4); NOS3 glu298asp (OR, 1.9; 95% CI, 1.1-3.4); NPPA 2238T > C (OR, 1.9; 95% CI, 1.0-3.4); and ADD1 gly460trp (OR, 1.5; 95% CI, 0.8-2.8). Additionally, for the NPPA and ADD1 single-nucleotide polymorphisms (SNPs), the homozygote variants had a significantly higher risk than the heterozygotes (OR, 7.5; 95% CI, 1.7-33.5 and OR, 4.9; 95% CI, 1.9-12.9, respectively). Three SNPs showed a strong interaction with maternal smoking. The risk for smokers with 1 or 2 variant alleles compared to nonsmokers with the wild-type allele were: NOS3 (OR, 5.2; 95% CI, 2.4-11.4); ICAM1 (OR, 5.2; 95% CI, 2.1-12.7); and NPPA (OR, 6.4; 95% CI, 2.8-14.6).

CONCLUSIONS

These results support the hypothesis of a vascular compromise as part of a multifactorial etiology of gastroschisis involving both genes and environmental factors.