Interaction between serotonin 2A receptor and endothelin-1 variants in association with hypertension in Japanese

Genetic and functional evidence links a missense variant in B4GALT1 to lower LDL and fibrinogen

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Changes in serum serotonin levels in patients with acute coronary syndrome and stable angina undergoing percutaneous coronary intervention

OBJECTIVE

Activated platelets release serotonin, causing platelet aggregation and vasoconstriction. Serotonin levels were investigated in patients with acute coronary syndrome (ACS) and chronic stable angina (CSA) treated with percutaneous coronary intervention (PCI).

METHODS

Consecutive patients undergoing PCI for either ACS or CSA were enrolled between July 2009 and April 2010. Patients were pre-treated with dual antiplatelet agents (aspirin and clopidogrel) before PCI. Serum serotonin levels, measured at baseline, pre- and post-PCI, and at 90 min, and 6, 12, 24 and 48 h following PCI, were compared between ACS and CSA groups.

RESULTS

Sixty-three patients with ACS and 60 with CSA were included. Overall baseline characteristics were similar between the two groups. Serotonin levels at post-PCI (55.2 ± 120.0 versus 20.1 ± 24.0) and at peak (regardless of timepoint; 94.0 ± 170.9 versus 38.8 ± 72.3) were significantly higher in the ACS versus CSA group. At 90 min and 6, 24 and 48 h post-PCI, serum serotonin was numerically, but not significantly, higher in patients with ACS. Serotonin levels fluctuated in both groups, showing an initial rise and fall, rebound at 24 h and drop at 48 h post-PCI.

CONCLUSIONS

In patients undergoing PCI, serum serotonin was more elevated in patients with ACS than those with CSA, suggesting the need for more potent and sustained platelet inhibition, particularly in patients with ACS.

Association between serotonin 2A receptor (HTR2A) genetic variations and risk of hypertension in a community-based cohort study

Background

Hypertension is one of the risk factors for obesity-related cardiovascular diseases. We investigated whether genetic variations in serotonin 2A receptor (HTR2A) were associated with hypertension.

Methods

We carried out a cross-sectional study in cohorts A (Ansan-Ansung cohort, N = 6039) and B (Wonju-Pyengchang cohort, N = 7524). Several genetic variants in HTR2A including rs7330636, rs9590999, rs2183057, and rs4942595 were selected and genotyped.

Results

In hypertensive participants in cohort A, the baseline systolic blood pressure and body mass index were 141.80 ± 17.20 mg/dL and 24.48 ± 4.75 kg/m², respectively, which were higher than in those without hypertension (p < 0.001). rs4942595TC genotype was associated with hypertension in cohort A (OR = 0.739), after adjusting for variables. Subjects with rs4942578AA genotype had a decreased risk of hypertension after adjusting for clinical factor (OR = 0.735) in cohort B, and an elevated risk of hypertension in cohort A (OR = 1.562). The logistic regression analysis showed that participants with rs4941573TC genotype were 1.327 times more likely to have a higher blood pressure than those with TT genotype (95% CI 1.101–1.599) in cohort B. Whereas, the OR for developing hypertension in subjects with rs17069883CC genotype compared to those with AA genotype was 1.447 (95% CI 1.018–2.056; p for trend = 0.040) in cohort A.

Conclusions

HTR2A genetic variations were associated with hypertension risk in our study.

Association between T102C 5-HT2A receptor gene polymorphism and 5-year mortality risk among Brazilian Amazon riparian elderly population

OBJECTIVE

Serotonin (5-HT) is a pleiotropic molecule that exerts several functions on brain and peripheral tissues via different receptors. The gene for the 5-HT2A receptor shows some variations, including a T102C polymorphism, that have been associated with increased risk of neuropsychiatric and vascular disorders. However, the potential impact of 5-HT2A imbalance caused by genetic variations on the human lifespan has not yet been established.

METHODS

We performed a prospective study involving an Amazon riparian elderly free-living population in Maués City, Brazil, with a 5-year follow-up. Out of a cohort of 637 subjects selected in July, 2009, we genotyped 471 individuals, including 209 males (44.4%) and 262 females (55.6%), all averaging 72.3 ± 7.8 years of age (ranging from 60 to 100 years).

RESULTS

The T102C-SNP genotypic frequencies were 14.0% TT, 28.0% CC, and 58.0% CT. From 80 elderly individuals who died during the period investigated, we observed significantly (P = .005) higher numbers of TT carriers (27.3%) and CC carriers (21.2%), compared to heterozygous CT carriers (12.5%). Cox-regression analysis showed that association between the T102C-SNP and elderly survival was independent of age, sex, and other health variables.

CONCLUSIONS

Our findings strongly suggest that imbalance in 5-HT2A may cause significant disturbances that lead to an increased susceptibility to death for individuals who are over 60 years of age.

Genetic associations with hypertension: meta-analyses of six candidate genetic variants

AIMS

The aim of this study was to perform combined analyses of six genetic variants for the risk of hypertension.

METHODS

After a comprehensive literature search for genetic variants involved with the association study of hypertension, we harvested a total of five genes (six variants) for the current meta-analyses. These genes consisted of CYP4A11 (T8590C), RGS2 (1891-1892del TC and G638A), HTR2A (T102C), GNAS (T393C), and HSD3B1 (T→C Leu338).

RESULTS

A total of 20 studies among 13,816 cases and 19,248 controls were retrieved for the meta-analyses of six genetic variants. It was shown that the RGS2 1891-1892del TC (OR=1.10, 95% CI=1.02-1.19, p=0.02) polymorphism and the CYP4A11 T8590C (OR=1.19, 95% CI=1.00-1.41, p=0.05) polymorphism were significantly associated with increased risk of hypertension. No association was found between the other four variants and the risk of hypertension.

CONCLUSION

This meta-analysis revealed that the RGS2 1891-1892del TC polymorphism and CYP4A11 T8590C polymorphism were associated with hypertension risk. However, HSD3B1 T→C Leu338, HTR2A T102C, GNAS T393C, and RGS2 G638A polymorphisms were not associated with hypertension risk.

Serotonin Receptor 2A (HTR2A) Gene Polymorphisms Are Associated with Blood Pressure, Central Adiposity, and the Metabolic Syndrome

BACKGROUND

Although the etiology of the metabolic syndrome remains unclear, recent evidence suggests that dysregulation of brain serotonergic activity may partly underlie the covariation of risk factors comprising the syndrome. In addition, prior studies have shown polymorphisms in the serotonin 2A receptor (HTR2A) gene to be associated with two syndrome components, hypertension and central adiposity. We conducted a study to confirm associations of HTR2A polymorphisms with elevated blood pressure and central adiposity and tested for association between these polymorphisms and the metabolic syndrome.

METHODS

The study sample included 934 unrelated individuals of European ancestry. We tested for association of two HTR2A polymorphisms, one in the promoter: (-1438[G/A]) and one in the first intron (2416 [C/T]), individually and as a diplotype, with elevated blood pressure, central adiposity, elevated fasting glucose, triglycerides, high density lipoprotein (HDL) cholesterol and presence of the metabolic syndrome, as defined by the American Heart Association/National Heart, Lung and Blood Institute (AHA/NHLBI) Scientific Statement Executive Summary.

RESULTS

Confirming previous reports, elevated blood pressure (>130/85 mm Hg) was associated with both the -1438 GG and 2416 TT genotypes and the GG/TT diplotype (ORs = 1.39-1.76); high waist circumference was associated with -1438 GG genotype only (OR = 1.57). In addition, both the -1438 GG and 2416 TT genotypes, and the GG/TT diplotype, predicted presence of the metabolic syndrome (ORs = 1.44-1.77). Fasting glucose, triglyceride and HDL cholesterol were not associated with either polymorphism.

CONCLUSIONS

Elevated blood pressure, central adiposity, and the metabolic syndrome are associated with polymorphisms in HTR2A gene.

Identification of hypertension-susceptibility genes and pathways by a systemic multiple candidate gene approach: the millennium genome project for hypertension

A multiple candidate-gene approach was used to investigate not only candidate genes, but also candidate pathways involved in the regulation of blood pressure. We evaluated 307 single nucleotide polymorphisms (SNPs) in 307 genes and performed an association study between 758 cases and 726 controls. Genes were selected from among those encoding components of signal transduction pathways, including receptors, soluble carrier proteins, binding proteins, channels, enzymes, and G-proteins, that are potentially related to blood pressure regulation. In total, 38 SNPs were positively (p<0.05) associated with hypertension. Replication of the findings and possible polygenic interaction was evaluated in five G-protein-related positive genes (GNI2, GNA14, RGS2, RGS19, RGS20) in a large cohort population (total n=9,700, 3,305 hypertensives and 3,827 normotensive controls). In RGS20 and GNA14, dominant models for the minor allele were significantly associated with hypertension. Multiple dimension reduction (MDR) analysis revealed the presence of gene-gene interaction between GNA14 and RGS20. The MDR-proved combination of two genotypes showed a significant association with hypertension (chi2=9.93, p=0.0016) with an odds ratio of the high-risk genotype of 1.168 (95% confidence interval [CI] [1.061-1.287]). After correction for all possible confounding parameters, the MDR-proved high-risk genotype was still a risk for hypertension (p=0.0052). Furthermore, the high-risk genotype was associated with a significantly higher systolic blood pressure (133.08+/-19.46 vs. 132.25+/-19.19 mmHg, p=0.04) and diastolic blood pressure (79.65+/-11.49 vs. 79.01+/-11.32 mmHg, p=0.019) in the total population. In conclusion, a systemic multiple candidate gene approach can be used to identify not only hypertension-susceptibility genes but also hypertension-susceptibility pathways in which related genes may synergistically collaborate through gene-gene interactions to predispose to hypertension.

Short/long heterozygotes at 5HTTLPR and white matter lesions in geriatric depression

OBJECTIVE

We examined the relationship between 5HTTLPR genotype and volume of magnetic resonance imaging (MRI) brain lesions.

METHOD

We studied 217 older depressed patients and 141 individuals in the comparison group using a standard brain MRI protocol to calculate lesion volumes. Genotype at 5HTTLPR was determined for each subject.

RESULTS

In age-adjusted models, the l/s genotype was associated with increased volume of total and white-matter lesions among depressed patients. This relationship lost significance in models controlling for reported hypertension.

CONCLUSIONS

The finding that 5HTTLPR heterozygotes have higher vascular lesion volumes may be related to development of hypertension.

NADH dehydrogenase subunit-2 237 Leu/Met polymorphism modifies the effects of alcohol consumption on risk for hypertension in middle-aged Japanese men

NADH dehydrogenase subunit-2 237 leucine/methionine (ND2-237 Leu/Met) polymorphism is associated with longevity in the Japanese population, and the ND2-237Met genotype may exert antiatherogenic effects. To investigate whether ND2-237 Leu/Met polymorphism is associated with risk of hypertension, we conducted a cross-sectional study of 398 Japanese male subjects. The frequency of hypertension was significantly higher in ND2-237Leu genotypic men than in ND2-237Met genotypic men. On analysis of covariance, the interaction between ND2-237 Leu/Met polymorphism and habitual drinking was significantly associated with both systolic blood pressure and diastolic blood pressure. Multiple logistic regression analysis revealed that the ND2-237Met genotype, particularly in younger subjects (age <60 years), had a lower odds ratio for hypertension than the ND2-237Leu genotype. Moreover, the association of ND2-237 Leu/Met polymorphism with hypertension may depend on the frequency of alcohol consumption. The odds ratio for hypertension was significantly higher in daily drinkers with ND2-237Leu when compared with non- or ex-drinkers with ND2-237Leu. However, the association between the ND2-237Met genotype and hypertension may not depend on the frequency of alcohol consumption. The present results suggest that ND2-237 Leu/Met polymorphism is associated with hypertension and that modification of hypertension risk is dependent on alcohol consumption in middle-aged Japanese men.

Genetics of stress response and stress-related disorders

The major findings regarding the genetics of stress response and stress-related disorders are: (i) variations in genes involved in the sympathetic system or in the hypothalamic-pituitary-adrenocortical axis are associated with altered stress responses; (ii) genes related to the renin-angiotensin-aldosterone system or inflammation/immune response show associations with cardiovascular disorders; (iii) genes involved in monoaminergic neurotransmitter systems are associated with bipolar disorder and unipolar depression. The vast majority of these association studies followed a conventional hypothesis-driven approach, restricting the gene selection to established candidates. This very conservative approach retarded our understanding of the complex interplay between genetic factors, stress response, and stress-related disorders. Chip-based whole-genome technologies will open up access to new unbiased and statistically efficient approaches that will help to identify new candidate genes, which should be thoroughly validated in clinical and preclinical confirmatory studies. This, together with the use of new text- and information-mining tools, will bring us closer to integrating all the findings into sophisticated models delineating the pathways from genes to stress response and stress-related disorders.

Migraine Is Associated with Enhanced Arterial Stiffness

Migraine is a common subtype of headache. Epidemiological studies have revealed that migraine could be an independent risk factor for ischemic stroke even in elderly subjects. Arterial stiffness is one of the major pathophysiological bases of stroke. In the present study, we cross-sectionally investigated the possible relationship between migraine and arterial stiffness in community-dwelling subjects. The study subjects were independently recruited from two sources (Group A, n=134, 68+/-5 years; Group B, n=138, 68+/-7 years). Augmentation index (AI), the ratio of augmented pressure by the reflection pressure wave to the pulse pressure, was obtained from the radial arterial waveform as an index of arterial stiffness. Brachial blood pressure was also measured simultaneously. Migraine was diagnosed using a previously validated questionnaire. The prevalence of migraine was 5.2% (Group A) and 16.7% (Group B). Subjects with migraine had higher radial AI in both Group A (migraine, 101+/-15%; other headache, 88+/-12%; no headache, 86+/-12%, p=0.003) and Group B (95+/-11%, 90+/-11%, 91+/-14%, p=0.058). Multiple linear regression analysis revealed that migraine was an independent determinant of AI (beta=0.154, p=0.002) after adjustment for other confounding factors: age (beta=-0.024, p=0.654); sex (beta=0.141, p=0.069); body height (beta=-0.215, p=0.005); systolic blood pressure (beta=0.174, p=0.001); medication for hypertension, hyperlipidemia, and diabetes mellitus (beta=-0.014, p=0.787); and heart rate (beta=-0.539, p<0.001). In a separate analysis by sex, migraine was also a significant determinant for AI (male, beta=0.246, p=0.019; female, beta=0.159, p=0.008). Migraine in the elderly could be a clinical manifestation of enhanced arterial stiffness.