Sex-specific effects of ACE I/D and AGT-M235T on pulse pressure: the HyperGEN Study

Age differences in arterial and venous extra-cerebral blood flow in healthy adults: contributions of vascular risk factors and genetic variants

Sufficient cerebral blood flow (CBF) and venous drainage are critical for normal brain function, and their alterations can affect brain aging. However, to date, most studies focused on arterial CBF (inflow) with little attention paid to the age differences in venous outflow. We measured extra-cerebral arterial and venous blood flow rates with phase-contrast MRI and assessed the influence of vascular risk factors and genetic polymorphisms (ACE insertion/deletion, COMT val158met, and APOEε4) in 73 adults (age 18-74 years). Advanced age, elevated vascular risk, ACE Deletion, and COMT met alleles were linked to lower in- and outflow, with no effects of APOE ε4 noted. Lower age-related CBF rate was unrelated to brain volume and was observed only in val homozygotes of COMTval158met. Thus, in a disease-free population, age differences in CBF may be notable only in persons with high vascular risk and carriers of genetic variants associated with vasoconstriction and lower dopamine availability. It remains to be established if treatments targeting alleviation of the mutable factors can improve the course of cerebrovascular aging in spite of the immutable genetic influence.

Associations of Renin-Angiotensin-Aldosterone System Genes With Blood Pressure Changes and Hypertension Incidence

BACKGROUND

The renin-angiotensin-aldosterone system (RAAS) plays an important role in blood pressure (BP) regulation. The current study uses single-marker and gene-based analyses to examine the association between RAAS genes and longitudinal BP phenotypes in a Han Chinese population.

METHODS

A total of 1,768 participants from the Genetic Epidemiology Network of Salt Sensitivity (GenSalt) follow-up study were included in the current study. Twenty-seven BP measurements were taken using random-zero sphygmomanometers at baseline and 2 follow-up visits. Mixed-effect models were used to assess the additive associations of 106 single-nucleotide polymorphisms (SNPs) in 10 RAAS genes with longitudinal BP changes and hypertension incidence. Gene-based analyses were conducted using the truncated product method. Attempts were made to replicate significant findings among Asian participants of the Multi-ethnic Study of Atherosclerosis (MESA). False discovery rate procedures were used to adjust for multiple testing.

RESULTS

During an average of 7.2 years of follow-up, average systolic and diastolic BP increased, and 32.1% (512) of participants free from hypertension at baseline developed hypertension. NR3C2 SNPs rs7694064 and rs6856803 were significantly associated with longitudinal changes in systolic BP (P interaction = 6.9×10(-5) and 8.2×10(-4), respectively). Through gene-based analysis, NR3C2 was found to be significantly associated with longitudinal systolic BP change (P value of 1.00×10(-7)), even after removal of significant markers rs7694064 and rs6856803 from the analysis. The association between NR3C2 and longitudinal systolic BP change was replicated in Asian MESA participants (P value of 1.00×10(-4)).

CONCLUSIONS

These findings indicate that NR3C2 may play an important role in BP progression and development of hypertension.

Association of (pro)renin receptor gene polymorphism with blood pressure in Japanese men: the Ohasama study

BACKGROUND

Recent studies have revealed that (pro)renin receptor ((P)RR), a newly identified member of the renin-angiotensin system (RAS), is associated with blood pressure regulation in animals. However, there is no information on (P)RR in humans. We investigated the association of (P)RR gene polymorphisms with blood pressure in a Japanese population.

METHODS

Subjects (n = 1,112) were recruited from participants in the Ohasama study, a Japanese cohort study. For the association study, we selected three polymorphisms: -782A>G (rs2968915), intervening sequence (IVS)5+169C>T (rs5918007), and +1513A>G (rs6609080). Because the (P)RR gene is on the X chromosome, men (n = 357) and women (n = 755) were analyzed separately.

RESULTS

In men, 24-h systolic blood pressure (SBP) and diastolic blood pressure (DBP) values, daytime SBP and DBP values, and nighttime SBP and DBP values were significantly higher in IVS5+169T allele carriers than C allele carriers. Multiple regression analysis showed that IVS5+169C>T was significantly and independently related to ambulatory blood pressure (ABP). IVS5+169C>T was not associated with casual blood pressure (CBP) in men. In women, there were no significant differences in blood pressure values among the three genotypes of IVS5+169C>T. This polymorphism had no significant association with any other clinical characteristic. -782A>G was weakly associated with ABP in men. +1513A>G was not associated with blood pressure values in either men or women.

CONCLUSIONS

We demonstrated for the first time that polymorphism of the (P)RR gene IVS5+169C>T is associated with ABP in Japanese men. This association suggests that (P)RR has a role in blood pressure regulation.

Angiotensinogen M235T associated with mitral valve prolapse in young Han Chinese male

BACKGROUND

A potential role for the renin-angiotensin system (RAS) in mitral valve prolapse (MVP) has been reported. The RAS genes are good candidates for evaluating the association with MVP. The angiotensinogen (AGT) gene has an important role in RAS and was shown to be related to MVP. However, no study on the association of AGT M235T in men with MVP has been reported. In this article, we investigated the potential role of AGT M235T polymorphism in men with MVP.

METHODS

Seventy-one unrelated study subjects with MVP, 236 control subjects (matched with respect to age and sex), and 178 community subjects from southern Taiwan were included in this study. All participants were male Han Chinese population. All cases fulfilled the criteria of MVP and the new echocardiographic criteria for MVP. The AGT M235T polymorphism was detected by polymerase chain reaction-restricted fragment length polymorphism.

RESULTS

There was a statistically significant difference in the M235 allelic frequency between MVP study subjects and control subjects (chi = 4.390; P = 0.036). The chi test for trend also showed that the MM genotype frequency had a statistically significant increase with MVP study subjects (chi = 4.339; P = 0.037).

CONCLUSIONS

The results suggest a significant association between MM genotype of AGT M235T polymorphism and MVP in men. Therefore, this study indirectly supports the idea that the polymorphism of AGT M235T should be considered when interpreting and designing genetic studies which underlie differences in blood pressure.