Association of the -344T/C polymorphism in aldosterone synthase gene promoter with left ventricular structure in Chinese Han: A meta-analysis

No consensus view has been published on the relationship between the aldosterone synthase gene (CYP11B2) -344C/T polymorphism and left ventricular hypertrophy (LVH) in Chinese Han. We undertook a meta-analysis to investigate the potential association of this polymorphism and left ventricular structure-related phenotypes, including left ventricular mass (LVM), left ventricular mass index (LVMI), left ventricular end systolic diameter (LVESD), left ventricular end diastolic dimension (LVEDD), left ventricular posterior wall thickness (LVPWT), and interventricular septal wall thickness (IVS). Studies in English and Chinese were found based on a systematic search of Medline, Embase, CNKI, and Wanfang databases. The dominant model (TT vs. TC+CC) and homozygote model (TT vs. CC) were selected to examine the association between the -344C/T polymorphism and LVH. The random-effects model was used to pool data. From a total of 3104 participants, despite the investigation of six echocardiographic indicators, we found no significant association between the -344C/T variant and LVH in the whole group and the subgroup analyses by blood pressure. However, in the subgroup of northern Han Chinese, TT genotype had higher LVPWT than CC genotype and TC genotype (p_{heterogeneity} = 0.4, p_value = 0.04, 95% CI 0.09 (0.00, 0.18)). In addition, no evidence of publication bias was observed. In conclusion, our meta-analysis indicated that subjects with TT genotype might have higher risk of developing LVH in northern Han Chinese.

Angiotensin-converting enzyme insertion/deletion polymorphism, 24-h blood pressure profile and left ventricular hypertrophy in hypertensive individuals: a cross-sectional study

Background

The absence of nocturnal blood pressure dipping (ND) identified by 24-h ambulatory blood pressure monitoring (ABPM) correlates with a worse cardiovascular prognosis. The renin–angiotensin system influences blood pressure levels and the occurrence of target organ damage (TOD). Thus, the aim of this study was to correlate the angiotensin-converting enzyme gene (ACE) insertion/deletion (I/D) polymorphism with the 24-h blood pressure profile and TOD in hypertensive individuals.

Methods

155 non-diabetic hypertensive individuals on antihypertensive treatment underwent ABPM. Peripheral blood samples were drawn for biochemistry and genetic analysis of the ACE I/D polymorphism by polymerase chain reaction. ND was defined as ≥10 % differences in the mean systolic blood pressure (BP) during wakefulness and sleep.

Results

There were no differences in clinical or biochemical variables or TOD in respect to ND status, except for higher BP levels during sleep (p < 0.001) in non-dippers. There was significant difference in the prevalence of left ventricular hypertrophy (LVH) between ACE genotypes (II: 13.0 %; ID: 34.1 %; DD: 46.5 %; p value = 0.024) with an increased risk in carriers of the DD genotype (OR = 5.80; IC 95 % 1.50–22.44; p value = 0.011). Carriers of the D allele had higher systolic BP during wakefulness and by ABPM (p < 0.05), higher left ventricular mass (117.3 ± 50.0 vs. 100.3 ± 25.7; p value = 0.017) and higher prevalence of LVH (37.4 vs. 12.5 %; OR = 4.14; 95 % IC: 1.17–14.65; p value = 0.028), compared to the II genotype.

Conclusions

The DD genotype is associated with a higher prevalence of LVH. The presence of the D allele appears to be associated with higher mean 24-h and wake systolic BP measured by ABPM in hypertensive patients under antihypertensive treatment.

Angiotensin-converting enzyme insertion/deletion gene polymorphisms and risk of intracerebral hemorrhage: a meta-analysis of epidemiologic studies

Studies investigating the association between the intron 16 insertion/deletion (I/D) polymorphism (rs4646994) in the angiotensin-converting enzyme (ACE) gene and risk of intracerebral hemorrhage (ICH) have reported conflicting results. We here performed a meta-analysis based on the evidence currently available from the literature to make a more precise estimation of this relationship. Published literature from the National Library of Medline and Embase databases were retrieved. Odds ratios (OR) and 95% confidence limits (CLs) were calculated in fixed- or random-effects models when appropriate. Subgroup analyses were performed by race. This meta-analysis included six case-control studies, which included 744 ICH cases and 1411 controls. The combined results based on all studies showed that ICH cases had a significantly lower frequency of ID genotype (OR (codominant model) = 0.43, 95% CL = 0.22, 0.84, p = 0.01). In the subgroup analysis by race, we found that ICH cases had a significantly lower frequency of II genotype in Asians (OR (recessive model) = 0.50, 95% CL = 0.38, 0.66, p < 0.001; OR (codominant model) = 0.25, 95% CL = 0.09, 0.71, p = 0.009). In conclusion, our meta-analysis suggests that ACE I/D polymorphisms are associated with ICH, especially in Asians.

Genetics of the renin-angiotensin system with respect to cardiac and blood pressure phenotypes in healthy newborn infants

INTRODUCTION

Left ventricular mass (LVM) is a strong predictor of various heart diseases. We examine the association between the G(-6)A AGT, I/D ACE, A1166C AGTR1, T(-344)C CYP 11β2, A538G MR and A10631G REN polymorphisms and LVM and blood pressure in newborn infants.

MATERIAL AND METHODS

The study included 211 healthy newborn infants. Two-dimensional M-mode echocardiography was used to assess LVM between days 3-4 after birth. Polymorphisms were determined by polymerase chain reaction - restriction fragment length polymorphism (PCR-RLFP).

RESULTS

AGTR1 genotype was significantly associated with neonatal systolic blood pressure (≥90 percentile). LVM indexes (LVMIs) were tested for association with genotypes in multivariate analysis. The carriers of the A allele of the AGT polymorphism had significantly higher LVM/body length (BL) values when compared with newborn infants homozygous for the G allele (p adjusted=0.03). The higher LVM/BL values were seen in the carriers of the A alleles of the AGTR1 polymorphism (p adjusted=0.046). All examined indexes (LVM/body surface area (BSA), LVM/BL, LVM/bodyweight (BW)) were associated with CYP11B polymorphism. The newborn infants homozygous for the T allele had significantly higher values of LVM/BSA, LVM/BL, and LVB/BW compared to non-TT-homozygous neonates (p adjusted=0.003; p adjusted=0.003; p adjusted=0.004 respectively).

CONCLUSION

The AGT, AGTR1, CYP11β polymorphisms are associated with increased LVMIs in newborns. This observation indicates that genetic factors may be modulating LVM at birth.

An insertion/deletion ACE polymorphism and kidney size in Polish full-term newborns

The number of nephrons is a multifactorial trait controlled by the interaction of environmental factors and genetic variants that influence the extent of branching nephrogenesis during foetal life. A correlation between renal mass and nephron number in newborns allows the use of the total kidney volume at birth as a surrogate for congenital nephron number. Since the renin-angiotensin system plays an important role in renal development we hypothesized that the common, functional insertion/deletion (I/D) polymorphism in the ACE gene might be responsible for the variation in kidney size amongst healthy individuals. We recruited 210 healthy Polish full-term newborns born to healthy women with uncomplicated pregnancies. The kidney volume was measured sonographically. Total kidney volume (TKV) was calculated as the sum of left kidney volume and right kidney volume. TKV was normalized to body surface area (TKV/BSA). The I and D alleles were identified using polymerase chain reaction. TKV/BSA in newborns carrying at least one insertion ACE allele was significantly reduced by approximately 8% as compared with homozygous newborns for the D allele (DD genotype) (105.1±23.6 vs. 114.2±28.2 cm(3)/m(2), p<0.05). The results of this study suggest that I/D ACE polymorphism may account for subtle variation in kidney size at birth, which reflects congenital nephron endowment.