Effects of Angiotensin II Type 1 Receptor Gene Polymorphisms on Insulin Resistance in a Japanese General Population: The Tanno-Sobetsu Study

A J-shaped Relationship between Sleep Duration and the Risk of Insulin Resistance in a General Japanese Population

Objective Data on the role of sleep in the risk of insulin resistance (IR) are lacking. We therefore examined the association between sleep duration and IR in a general Japanese population. Methods Data of 1,344 individuals 34 to 89 years old from the Tanushimaru Study were analysed. IR was calculated using the fasting plasma glucose level×fasting insulin level/405, i.e. the homeostasis model assessment of IR (HOMA-IR). IR was defined as a HOMA-IR ≥1.73 based on the diagnostic criteria used in Japan. Information regarding sleep duration was collected via questionnaire. Results The frequencies of IR and metabolic syndrome (MetS) were 36.7% and 26.9%, respectively. A J-shaped relationship between sleep duration and IR was observed, and the same relationship was also shown between sleep duration and MetS; however, the relationship with MetS disappeared after adjusting for age, sex, and other confounding factors. Conclusion A J-shaped relationship was observed between sleep duration and the risks of IR in a general Japanese population.

Association of polymorphism genes , , and with risk of hyperinsulinism and insulin resistance in the Kazakh population

Hyperinsulinism and insulin resistance are closely associated with several common diseases including type 2 of diabetes, cardiovascular diseases, and metabolic syndrome. The present study aimed to determine the association between hyperinsulinism, insulin resistance and the polymorphism of genes, including angiotensin II receptor type 1 (AGTR1), angiotensinogen (AGT), β2-adrenoreceptor (ADRB2) and lipoprotein lipase (LPL), in the Kazakh population. The design of the current research was a case-control study, involving 460 subjects (age range, 18-65 years). For every subject, plasma glucose, insulin, total cholesterol, triglycerides, high-density lipoprotein, low-density lipoprotein, apolipoprotein B and apolipoprotein A1 were examined. Moreover, reverse transcription-quantitative PCR was conducted to detect the polymorphism genes LPL Ser447Ter, ADRB2 Gln27Glu, AGT Thr174Met and AGTR1 A1166C. Hyperinsulinism was considered when the insulin level was elevated >24.9 IU/ml. The homeostasis model assessment insulin resistance (HOMA-IR) was used to evaluate insulin resistance. The subjects were divided into hyperinsulinism (17 men and 24 women) and normal level insulin (214 men and 205 women) groups, which were also split into insulin resistance group (HOMA-IR >2.7; 80 men and 105 women) and those without insulin resistance group (151 men and 124 women). The results suggested that LPL Ser447Ter (rs328) allele G was associated with a lower risk of hyperinsulinism (P=0.037). Furthermore, polymorphisms of genes ADRB2 Gln27Glu (rs1042714), AGT Thr174Met (rs4762) and AGTR1 A1166C (rs5186) were not associated with hyperinsulinism and insulin resistance in the Kazakh population. No interaction was identified between LPL Ser447Ter, ADRB2 Gln27Glu, AGT Thr174Met and AGTR1 A1166C. Therefore, the results indicated that haplotype combinations were not associated with insulin resistance.

Serum Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) is Independently Associated with Insulin Resistance, Triglycerides, Lipoprotein(a) Levels but not Low-Density Lipoprotein Cholesterol Levels in a General Population

Aim: Proprotein convertase subtilisin/kexin type 9 (PCSK9) has been identified as an important regulator of low-density lipoprotein (LDL) receptor processing. Evolocumab and alirocumab are PCSK9 inhibitors; however, little is known about the association between PCSK9 levels and lipid profiles in a general population. Because PCSK9 inhibitors have LDL-C lowering effects, we investigated whether there is a positive correlation between serum PCSK9 levels and LDL-C or lipoprotein(a) [Lp(a)].

Methods: In Uku town, 674 residents (mean age; 69.2 ± 8.3 years) received health check-ups. The participants underwent a physical examination and blood tests, including PCSK9 and Lp(a). Serum PCSK9 and Lp(a) were measured by ELISA and Latex methods, respectively. HOMA-IR was calculated by fasting plasma glucose × insulin levels/405.

Results: The mean (range) of PCSK9 and Lp(a) were 211.2 (49–601) ng/mL and 60 (1–107) mg/dL, respectively. Because of a skewed distribution, the log-transformed values were used. With univariate linear regression analysis, PCSK9 levels were associated with Lp(a) (p = 0.028), triglycerides (p < 0.001), and HOMA-IR (p < 0.001), but not with LDL-C (p = 0.138) levels. Multiple stepwise regression analysis revealed that serum PCSK9 levels were independently associated with triglycerides (p < 0.001), Lp(a) (p = 0.033) and HOMA-IR (p = 0.041).

Conclusions: PCSK-9 is independently associated with triglycerides, Lp(a) levels, and HOMA-IR, but not LDL-C, in a relatively large general population sample.

The Role of Overexpressed Apolipoprotein AV in Insulin-Resistant Hepatocytes

In this paper, we sought to explore the relationship between apolipoprotein AV (APOAV) overexpression and insulin resistance in hepatocytes. The insulin-resistant HepG2 cell model was constructed, and then, APOAV-overexpressed HepG2 cells (B-M) were induced by infecting with a recombinant adenovirus vector. Microarray data were developed from B-M samples compared with negative controls (A-con), and the microarray data were analyzed by bioinformatic methods. APOAV-overexpression induced 313 upregulated genes and 563 downregulated ones in B-M sample. The differentially expressed genes (DEGs) were significantly classified in fat digestion and absorption pathway. Protein-protein interaction network was constructed, and AGTR1 (angiotensin II receptor type 1) and P2RY2 (purinergic receptor P2Y, G-protein coupled 2) were found to be the significant nodes closely related with G-protein related signaling. Additionally, overexpression of APOAV could change the expression of Glut4 and release the insulin resistance of hepatic cells. Thus, APOAV overexpression may prevent the insulin resistance in liver cells by mediating the genes such as AGTR1 and P2RY2.

The Association between Angiotensin II Type 1 Receptor Gene A1166C Polymorphism and Non-alcoholic Fatty Liver Disease and Its Severity

BACKGROUND Genetic predisposition may have important role in pathogenesis of non-alcoholic fatty liver disease (NAFLD). Angiotensin II type I receptor (AGTR1) has been known to involve in the process of liver steatosis and fibrosis. This study aimed to investigate the association between AGTR1 A1166C polymorphism and NAFLD. METHODS A cross-sectional study was conducted during May 2014-May 2015 among healthy adults referring to our radiology clinic for abdominal sonography. AGTR1 A1166C polymorphism was evaluated in subjects with NAFLD and healthy individuals using allelic discrimination method. RESULTS 58 subjects with NAFLD were compared with 88 healthy individuals without NAFLD. The frequency of AA and CC genotypes of AGTR1 was significantly higher in patients with NAFLD compared with controls (p = 0.029 and 0.042, respectively). C allele was more detected in subjects with NAFLD compared with the healthy controls (OR: 2.1; 95% CI: 1.23-3.61, p = 0.006). CC genotype (OR: 10.62; 95% CI: 1.05-106.57, p = 0.045) and C allele (OR: 6.81; 95% CI: 1.42- 32.48, p = 0.016) were also predictors of severe fatty liver disease in our study population. CONCLUSION Our results provide the first evidence that AGTR1 gene A1166C polymorphism not only is associated with NAFLD and but also may predict its severity.

An atlas of G-protein coupled receptor expression and function in human subcutaneous adipose tissue

G-protein coupled receptors (GPCRs) are involved in the regulation of adipose tissue function, but the total number of GPCRs expressed by human subcutaneous adipose tissue, as well as their function and interactions with drugs, is poorly understood. We have constructed an atlas of all GPCRs expressed by human subcutaneous adipose tissue: the 'adipose tissue GPCRome', to support the exploration of novel control nodes in metabolic and endocrine functions. This atlas describes how adipose tissue GPCRs regulate lipolysis, insulin resistance and adiponectin and leptin secretion. We also discuss how adipose tissue GPCRs interact with their endogenous ligands and with GPCR-targeting drugs, with a focus on how drug/receptor interactions may affect lipolysis, and present a model predicting how GPCRs with unknown effects on lipolysis might modulate cAMP-regulated lipolysis. Subcutaneous adipose tissue expresses 163 GPCRs, a majority of which have unknown effects on lipolysis, insulin resistance and adiponectin and leptin secretion. These GPCRs are activated by 180 different endogenous ligands, and are the targets of a large number of clinically used drugs. We identified 119 drugs, acting on 23 GPCRs, that are predicted to stimulate lipolysis and 173 drugs, acting on 25 GPCRs, that are predicted to inhibit lipolysis. This atlas highlights knowledge gaps in the current understanding of adipose tissue GPCR function, and identifies GPCR/ligand/drug interactions that might affect lipolysis, which is important for understanding and predicting metabolic side effects of drugs. This approach may aid in the design of new, safer therapeutic agents, with fewer undesired effects on lipid homeostasis.

The AGTR1 gene A1166C polymorphism as a risk factor and outcome predictor of primary intracerebral and aneurysmal subarachnoid hemorrhages

Associations between the angiotensin II type 1 receptor (AGTR1) gene A1166C polymorphism and hypertension, aortic abdominal aneurysms (as a risk factor) as well as cardiovascular disorders (as a risk factor and an outcome predictor) have been demonstrated. We aimed to investigate the role of this polymorphism as risk factors and outcome predictors in primary intracerebral hemorrhage (PICH) and aneurysmal subarachnoid hemorrhage (aSAH). We have prospectively recruited 1078 Polish participants to the study: 261 PICH patients, 392 aSAH patients, and 425 unrelated control subjects. The A1166C AGTR1 gene polymorphism was studied using the tetra-primer ARMS-PCR method. Allele and genotype frequencies were compared with other ethnically different populations. The A1166C polymorphism was not associated with the risk of PICH or aSAH. Among the aSAH patients the AA genotype was associated with a good outcome, defined by a Glasgow Outcome Scale of 4 or 5 (p<0.02). The distribution of A1166C genotypes in our cohort did not differ from other white or other populations of European descent. In conclusion, we found an association between the A1166C AGTR1 polymorphism and outcome of aSAH patients, but not with the risk of PICH or aSAH.

Independent association of elevated serum hepatocyte growth factor levels with development of insulin resistance in a 10-year prospective study

OBJECTIVE

Hepatocyte growth factor (HGF) receptors form a hybrid complex with insulin receptors in the liver of mice, which lead to robust signalling to regulate glucose metabolism. Serum HGF levels are high in subjects with metabolic syndrome and/or obesity. Accordingly, we prospectively investigated the relationship between HGF and the development of insulin resistance (IR) in a general population without IR at baseline.

METHODS

A total of 1492 subjects received health examinations. After excluding subjects with diabetes and/or IR (n = 402) at baseline, the remaining subjects (n = 1090) were followed-up 10 years later. Complete data sets were available from 716 subjects for prospective analysis. Logistic regression was performed to determine factors associated with the development of IR after 10 years.

RESULTS

In subjects without diabetes at baseline, serum HGF levels were higher (0·26 ± 0·10 ng/ml, n = 259) in subjects with IR than without it (0·22 ± 0·09 ng/ml, n = 1090). After deleting subjects who developed liver disease during follow-up, 188 were found to have developed IR at 10 years after the original screening. HGF (P < 0·05), age (P < 0·001), homoeostasis model assessment index (P < 0·001), HDL-c (P < 0·05; inversely) and hypertensive medication (P < 0·05) were significantly associated with the development of IR by multivariate stepwise logistic regression analysis. A significant (P < 0·05) relative risk [1·75 (95%CI: 1·01-3·12)] for the development of IR was observed in the highest (≥0·30 ng/ml) vs the lowest categories (<0·15 ng/ml) of HGF after adjustments for confounders.

CONCLUSIONS

Our 10-year prospective study suggests that elevated serum HGF levels were significantly associated with the development of IR.

Association of angiotensin-converting enzyme and angiotensin II type I receptor gene polymorphisms with extreme obesity in Polish individuals

There is strong evidence for the presence of a functional renin-angiotensin system in human adipose tissue. The aim of our study was to investigate the association of polymorphic variants of angiotensin-converting enzyme gene (ACE I/D) and angiotensin II type I receptor gene (AGTR1 A1166C) with extreme obesity and obesity-associated type 2 diabetes mellitus (T2DM) and to examine their combined effect on extremely obese patients. Overall, no significant associations were detected between ACE and AGTR1 gene polymorphisms and extreme obesity. However, extremely obese patients with T2DM showed an increased frequency of ACE II genotype compared with controls (p<0.05) and with non-diabetic extremely obese patients (p<0.01). The results suggest that II genotype of ACE was a significant contributor to extreme obesity in AA homozygotes of AGTR1 gene, regardless of the presence of T2DM. Moreover, the analysis of genetic polymorphisms demonstrated that ACE II and AGTR1 AC genotypes were most frequently observed in patients with extreme obesity and T2DM. On the basis of our results, we suggest that ACE II homozygosity may be a significant predictor of extreme obesity and T2DM and that the interaction between ACE and AGTR1 genes may be considered a predisposing factor for extreme obesity and extreme obesity-associated T2DM development.

Influence of renin angiotensin system gene polymorphisms on visit-to-visit blood pressure variability in hypertensive patients

BACKGROUND

Visit-to-visit blood pressure (BP) variability has been reported to be a major risk for cardiovascular events. Renin angiotensin system (RAS) gene polymorphisms are reportedly genetic risk factors for cardiovascular diseases and arterial stiffness. In this study, we aimed to reveal the relationship between visit-to-visit BP variability and RAS gene polymorphisms.

METHODS

Study subjects included 427 essential hypertension patients from the Non-Invasive Atherosclerotic Evaluation in Hypertension study cohort, whose BP was measured during at least six outpatient visits. We analyzed the correlation between visit-to-visit variability in systolic BP (SBP) and RAS gene polymorphisms.

RESULTS

We identified angiotensinogen M235T, angiotensin II type 1 receptor A1166C, and angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphisms. Only ACE I/D polymorphisms were correlated with variability in diastolic BP; no gene polymorphisms were correlated with variability in SBP.

CONCLUSIONS

RAS gene polymorphisms, especially ACE I/D polymorphisms, might genetically influence the visit-to-visit BP variability in hypertensive patients.

Possible role of microsomal epoxide hydrolase gene polymorphism as a risk factor for developing insulin resistance and type 2 diabetes mellitus

The purpose of this study was to investigate the effects of mEPHX1 polymorphisms on risk of type 2 diabetes mellitus (T2DM) and insulin resistance (IR). One hundred and twelve patients with the diagnosis of T2DM and 150 control subjects were enrolled in the study. We investigated the two polymorphisms of the mEPHX1 gene (exon 3 Tyr113His and exon 4 His139Arg) using PCR-RFLP. Among diabetics, the frequencies obtained for the exon 3 mEPHX1 Tyr113 and His113 alleles were 46.9 and 53.1 %, respectively. In the control group, the frequencies were 70.7 and 29.3 %, respectively (P = 0.0001, OR = 2.73, 95 % CI = 1.9-3.91). The prevalence of mEPHX1 exon 3 Tyr/His and His/His was statistically significant (P = 0.004; 0.0001, respectively) when compared with the mEPHX1 exon 3 Tyr/Tyr homozygous carriers in both T2DM patients and in controls. We found that the His113 allele carriers had higher fasting insulin level, HOMA-IR, β cell activity, and lower insulin sensitivity compared to the wild type (P = 0.0001, 0.029, 0.0001, and 0.001, respectively). In contrast, there was no significant difference in exon 4 polymorphisms between patients and controls. However, our data revealed that the His139/His139 genotype carriers had higher fasting insulin level, and lower insulin sensitivity compared to Arg139 allele carriers (P = 0.02, and 0.001, respectively). Our study has shown for the first time that minor Tyr113 allele of mEPHX1 polymorphism had a higher risk of T2DM and IR occurrence with lower insulin sensitivity, while mEPHX1 exon 4 polymorphism had no significant association with T2DM and IR.

The effects of the renin-angiotensin-aldosterone system gene polymorphisms on insulin resistance in hypertensive families

INTRODUCTION

The hereditability of insulin resistance has been demonstrated in both familial and twin studies. The effects of renin-angiotensin-aldosterone system gene polymorphisms on insulin resistance remain inconclusive.

METHODS

This is a sibling-based association study. Polymorphisms of renin-angiotensin-aldosterone system genes were examined in 1113 hypertension and 676 normotension siblings from Chinese and Japanese hypertensive families. The generalized estimation equations method was used to compare the differences in metabolic variables between hypertension and normotensive siblings.

RESULTS

For the G-6A polymorphism of AGT, GG siblings had lower 2-h insulin than siblings carrying the A allele (p=0.006). Siblings with different variants of the angiotensin II type 1 receptor A1166C had no difference in metabolic variables. Siblings carrying the D allele of the angiotensin converting enzyme gene had higher levels of fasting glucose, fasting insulin, area under the curve of insulin levels and the homeostasis model assessment of insulin resistance than II siblings (all p<0.05). Lower levels of fasting glucose and 2-h glucose were observed in siblings with the T allele than their CC homozygotes for the C-344T polymorphism of CYP11B2 (p<0.05). Siblings carrying three high-risk genotypes of the angiotensin converting enzyme, angiotensinogen and CYP11B2 had higher fasting glucose level than siblings carrying no high-risk genotypes (p=0.011).

CONCLUSION

Our comprehensive analysis of renin-angiotensin-aldosterone system gene polymorphisms demonstrates that the angiotensin converting enzyme and CYP11B2 gene polymorphisms are associated with insulin resistance in hypertensive families.

A single nucleotide polymorphism of the adenosine deaminase, RNA-specific gene is associated with the serum triglyceride level, abdominal circumference, and serum adiponectin concentration

BACKGROUND

Single nucleotide polymorphisms (SNPs) of the adenosine deaminase, RNA-specific (ADAR) gene were reported to be associated with human longevity. There are possibilities that ADAR is associated with major risk factors of atherosclerotic cardiovascular diseases (CVD), such as hypertension, diabetes, dyslipidemia, and obesity.

OBJECTIVE

To investigate the association between SNPs of the ADAR gene and clinical data associated with major risk factors of atherosclerotic CVD.

SUBJECTS

A total of 1504 general population residents (586 males and 918 females) of two towns, Tanno-cho and Sobestu-cho, in Hokkaido, Japan.

METHODS

Clinical data associated with risk factors of atherosclerotic CVD were collected from these study subjects. DNA from peripheral blood and written informed consent were obtained. Three single nucleotide polymorphisms of ADARB1 and ADARB2, which were previously reported to be associated with longevity, were genotyped employing the TaqMan PCR method. The associations between SNPs in ADARB1 and ADARB2 and clinical parameters related to risk factors of atherosclerosis were analyzed.

RESULTS

On uni- and multivariate analyses, rs2805533 in ADARB2 was significantly associated with the abdominal circumference, body mass index, serum triglyceride level, and serum adiponectin level. The subjects with the AA genotype of rs2805533 had a greater abdominal circumference, higher body mass index, higher triglyceride level, and lower adiponectin level than those with AG and GG genotypes.

CONCLUSION

The SNP in ADARB2 related to longevity is associated with metabolic disorders. This finding suggests that genetic factors modulate human longevity via the regulation of metabolic factors such as abdominal obesity and lipid profiles.

Plasma aldosterone levels and development of insulin resistance: prospective study in a general population

Aldosterone plays a role in hypertension, and hypertension is prevalent in patients with insulin resistance. Cross-sectional studies have reported that plasma aldosterone levels are higher in patients with insulin resistance. However, it is not known whether plasma aldosterone levels predict the development of insulin resistance. Subjects of the present study were 1235 local residents (490 men and 745 women) who participated in health screenings in Japan in 1999. Plasma aldosterone levels were measured by radioimmunoassay. We investigated the cross-sectional relationship between plasma aldosterone levels and insulin resistance (homeostasis model assessment index ≥1.73 according to the diagnostic criteria used in Japan) in 1088 nondiabetic participants. At the 10-year follow-up, 141 subjects had died, and 260 subjects refused re-examination. We performed a prospective analysis of 564 subjects to predict incident insulin resistance. We found a significant (P<0.001) cross-sectional relationship between plasma aldosterone and homeostasis model assessment index at baseline. In the prospective analysis, a significantly higher (P<0.05) relative risk (1.71 [95% CI: 1.03-2.84]) was observed in the highest tertile versus lowest tertile of plasma aldosterone for the development of insulin resistance, after adjustment for confounding factors. This 10-year prospective study demonstrated that plasma aldosterone levels predicted the development of insulin resistance in a general population.

Association between angiotensin II type 1 receptor gene polymorphism and metabolic syndrome in a young female Iranian population

BACKGROUND AND AIMS

The overall prevalence of obesity and metabolic syndrome (MetS) is increasing among children and adolescents and can predispose to type II diabetes mellitus and cardiovascular disease. There are reported associations between an angiotensin II type I receptor gene polymorphism (AT(1)R/A1166C) with hypertension, myocardial infarction, insulin resistance and cardiovascular disease risk. In the present study, we aimed to investigate whether the AT(1)R/A1166C polymorphism was associated with MetS among adolescent Iranian girls.

METHODS

A total of 350 adolescent girls aged 15-17 years from high schools and different educational zones of Mashhad city participated in this population-based, genetic association study. Of these individuals, 101 patients had MetS (defined by the NCEP-ATP III criteria); the remaining 249 age-matched girls were considered as the control group. All subjects were genotyped for the AT(1)R/A1166C polymorphism using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique.

RESULTS

Frequencies of the AA, AC and CC genotypes were 164 (65.9%), 80 (32.1%) and 5 (2.0%) in the control group and 79 (78.2%), 20 (19.8%) and 2 (2.0%) in patients, which were not consistent with the Hardy-Weinberg equilibrium (p <0.05 and p <0.001, respectively). Frequency of the AT(1)R C allele was found to be significantly lower in patients compared with controls (p <0.05).

CONCLUSIONS

Our findings suggested that the 1166C allele of AT(1)R gene may be associated with a decreased risk of MetS in adolescent Iranian females.

Variation in OSBPL10 is associated with dyslipidemia

The oxysterol hypothesis of cholesterol homeostasis states that oxysterol mediates feedback regulation of cholesterol biosynthesis. Oxysterol-binding proteins have been implicated in the control of lipid synthesis and metabolism. In a genome-wide case-control association study in Japanese individuals, we found that the three single-nucleotide polymorphisms (SNPs) with the smallest P-values were located in the fifth intronic region of the oxysterol-binding protein-like 10 (OSBPL10) gene. In this study, we examined the association between polymorphisms in the OSBPL10 gene and risk factors for the metabolic syndrome in the Tanno and Sobetsu Study. We selected four SNPs, including three non-coding SNPs in intron 5 and a coding SNP (D254N) in exon 6. Genotype frequencies of the polymorphisms satisfied the conditions for Hardy-Weinberg equilibrium. We found that the low-density lipoprotein (LDL) cholesterol of individuals with the rs2290532 (D254N) polymorphism was significantly greater in subjects with the CC+CT genotype than in subjects with the TT genotype (124.3+/-1.3 vs. 111.6+/-4.1 mg per 100 ml, P=0.009). However, there were no significant differences in systolic or diastolic blood pressure, high-density lipoprotein cholesterol or triglyceride levels. Multiple regression analysis showed that rs2290532 (D254N) was associated with LDL cholesterol independent of age, sex or body mass index. Comparison of the genotype frequency in both groups indicated that the genotype associated with low risk (TT) reduced the risk of hyper-LDL cholesterolemia significantly (P=0.003), with an odds ratio of 0.35 (95% confidence interval=0.17-0.76). Overall, the rs2290532 (D254N) polymorphism in OSBPL10 may predispose individuals with this SNP to hyper-LDL cholesterolemia.

A Polymorphism Regulates CYP4A11 Transcriptional Activity and Is Associated With Hypertension in a Japanese Population

CYP4A11 oxidizes arachidonic acid to 20-hydroxyeicosatetraenoic acid, a metabolite with renovascular and tubular function in humans. A previous study demonstrated a significant association between the CYP4A11 gene polymorphism and hypertension; however, the precise mechanism of the association has not been clarified. To assess the involvement of CYP4A11 in the pathogenesis of hypertension, we sought to identify a functional polymorphism of CYP4A11 and examined its impact on predisposition to hypertension in the Tanno-Sobetsu Study. The −845A/G polymorphism was identified in the promoter region of CYP4A11 by direct sequencing. Luciferase expression driven by the promoter of CYP4A11 containing the wild-type −845GG genotype was 30% lower than expression with the variant −845AA genotype. Gel mobility shift assays with nuclear protein extracts showed specific binding to probes containing the variant −845GG. To assess the effect of CYP4A11 polymorphisms on hypertension, we also carried out a case-control study using 4 single nucleotide polymorphisms (−845A/G, −366C/T, 7119C/T, and 8590T/C) in the Tanno-Sobetsu Study. The odds ratio for hypertension in participants with the AG+GG genotype of −845A/G was 1.42 ( P =0.008), and the odds ratio for hypertension of the TT genotype of 7119C/T was 1.37 ( P =0.037) after adjusting for confounding factors. The haplotype-based case-control analysis using 4 single nucleotide polymorphisms revealed a significant haplotype (G-C-T-T) that was significantly associated with hypertension, with an odds ratio of 1.44 ( P =0.006) after adjusting for confounding factors. We have identified a functional variant (−845A/G) of CYP4A11 that is significantly associated with hypertension and that appears to be a novel candidate for a predisposing factor for hypertension.

Association between the AGTR1 polymorphism +1166A>C and serum levels of high-sensitivity C-reactive protein

Genetic factors have been shown to influence high-sensitivity C-reactive protein (hsCRP) levels, however, which genes that are involved in this process remains to be clarified. The renin-angiotensin system (RAS) is of importance for the regulation of inflammation, and blockade of angiotensin II type 1 receptors (AGTR1) influences hsCRP levels. These findings prompted us to investigate whether a polymorphism in the AGTR1 gene may influence hsCRP levels. Additionally, a polymorphism in the CRP gene that has previously been shown to influence hsCRP levels was genotyped. Serum levels of hsCRP were measured in 270 42-year-old women recruited from the population registry. Two single nucleotide polymorphisms were analysed: +1166A>C and +1444C>T of the AGTR1 and CRP gene, respectively. The A allele of the AGTR1 polymorphism +1166A>C was dose-dependently associated with higher hsCRP levels (p=0.014, adjusted for confounding factors and multiple comparisons). hsCRP levels were not significantly influenced by the CRP +1444C>T genotype; however, an interaction between the two studied polymorphisms with respect to hsCRP levels was observed (p=0.018). The significant association between the AGTR1 polymorphism and hsCRP levels, which appears to be independent of anthropometric and metabolic traits, is yet another indication of a direct influence of RAS on inflammation.