Association of DNA polymorphisms within the CYP11B2/CYP11B1 locus and postoperative hypertension risk in the patients with aldosterone-producing adenomas

Genetic variants in CYP11B1 influence the susceptibility to coronary heart disease

BACKGROUND

Genetic factors are important risk factors to develop coronary heart disease (CHD). In this study, we mainly explored whether CYP11B1 mutations influence CHD risk among Chinese Han population.

METHODS

Six variants were genotyped using Agena MassARRAY system from 509 CHD patients and 509 healthy controls. The correlations between CYP11B1 mutations and CHD risk were assessed using odds ratio (OR) and 95% confidence interval (95% CI) by logistic regression. The haplotype analysis and were ultifactor dimensionality reduction (MDR) were conducted.

RESULTS

In the overall analysis, CYP11B1 polymorphisms were not correlated with CHD susceptibility. In the stratified analysis, we found that rs5283, rs6410, and rs4534 are significantly associated with susceptibility to CHD dependent on age and gender (p < 0.05). Moreover, we also observed that rs5283 and rs4534 could affect diabetes/hypertension risk among CHD patients (p < 0.05). In addition, the C_rs4736312A_rs5017238C_rs5301G_rs5283T_rs6410C_rs4534 haplotype of CYP11B1 reduce the susceptibility to CHD (p < 0.05).

CONCLUSIONS

We found that rs4534, rs6410 and rs5283 in CYP11B1 gene influence the susceptibility to CHD, which depend on age and gender.

Hypertension outcomes of adrenalectomy in patients with primary aldosteronism: a systematic review and meta-analysis

BACKGROUND

The hypertension cure rate of unilateral adrenalectomy in primary aldosteronism (PA) patients varies widely in existing studies.

METHODS

We conducted an observational meta-analysis to summarize the pooled hypertension cure rate of unilateral adrenalectomy in PA patients. Comprehensive electronic searches of PubMed, Embase, Cochrane, China National Knowledge Internet (CNKI), WanFang, SinoMed and Chongqing VIP databases were performed from initial state to May 20, 2016. We manually selected eligible studies from references in accordance with the inclusion criteria. The pooled hypertension cure rate of unilateral adrenalectomy in PA patients was calculated using the DerSimonian-Laird method to produce a random-effects model.

RESULTS

Forty-three studies comprising approximately 4000 PA patients were included. The pooled hypertension cure rate was 50.6% (95% CI: 42.9-58.2%) for unilateral adrenalectomy in PA. Subgroup analyses showed that the hypertension cure rate was 61.3% (95% CI: 49.4-73.3%) in Chinese studies and 43.7% (95% CI: 38.0-49.4%) for other countries. Furthermore, the hypertension cure rate at 6-month follow-up was 53.3% (95% CI: 36.0-70.5%) and 49.6% (95% CI: 40.9-58.3%) for follow-up exceeding 6 months. The pooled hypertension cure rate was 50.9% (95% CI: 40.5-61.3%) from 2001 to 2010 and 50.2% (95% CI: 39.0-61.5%) from 2011 to 2016.

CONCLUSIONS

The hypertension cure rate for unilateral adrenalectomy in PA is not optimal. Large clinical trials are required to verify the utility of potential preoperative predictors in developing a novel and effective prediction model.

Aldosterone Synthase Promoter Polymorphism and Cardiovascular Phenotypes in a Large, Multiethnic Population-Based Study

BACKGROUND

A single-nucleotide polymorphism in the aldosterone synthase gene (CYP11B2) promoter [-344C/T, rs1799998] has been reported to associate with cardiovascular phenotypes.

METHODS

The Dallas Heart Study is a large, multiethnic cohort with a high prevalence of hypertension. We genotyped 3452 Dallas Heart Study participants for -344C/T. Generalized linear models were used to assess whether variation at -344C/T associated with plasma aldosterone concentration (PAC), systolic and diastolic blood pressure (SBP and DBP), plasma glucose (in persons with no diabetes), HOMA IR (Homeostasis Model Assessment as an Index of Insulin Resistance), and left ventricular (LV) mass indexed to height. Systolic blood pressure and DBP were significantly higher in blacks compared with whites (P < 0.001 for SBP and for DBP) and Hispanics (P < 0.001 for SBP and for DBP). Log-transformed body mass index was also significantly higher in blacks compared with whites (P < 0.001), but not Hispanics (P = 0.10). Log-transformed PAC was higher in whites compared with blacks (P < 0.001), but did not differ significantly in whites compared with Hispanics (P = 0.73). In univariate and multivariable analysis, -344C/T was not significantly associated with PAC within any ethnicity. In univariate and multivariable analysis, -344C/T was not associated with SBP or DBP within any ethnicity. After adjustment for multiple testing, univariate and multivariable analyses revealed no association between -344C/T and plasma glucose in patients with no diabetes, HOMA IR, or LV mass indexed to height.

CONCLUSIONS

We were unable to reproduce previously reported associations between -344C/T and PAC, blood pressure, plasma glucose, or LV mass. Methodological differences might explain the differences between our findings and those previously reported.

Gene Expression Profile of Persistent Postoperative Hypertension Patients with Aldosterone-producing Adenomas

Background:

Hypertension often persists after adrenalectomy for primary aldosteronism (PA). Many studies have analyzed the outcomes of adrenalectomy for aldosterone-producing adenomas (APA) to identify predictive factors for persistent hypertension. However, differentially expressed genes in persistent postoperative hypertension remain unknown. Our aim was to describe gene expression profile of persistent postoperative hypertension patients with APA.

Methods:

In this study, we described and compared gene expression profiles in persistent postoperative hypertension and postoperative normotension in Chinese patients with APA using microarray analysis. Confirmation was performed with quantitative real time-polymerase chain reaction analysis. Bioinformatic analysis (gene ontology analysis, pathway analysis and network analysis) was used for further research.

Results:

Microarray analysis identified a total of 99 differentially expressed genes, including 18 up-regulated and 81 down-regulated genes. Among the dysregulated genes were fat atypical cadherin 1 as well as fatty acid binding protein 4 and other genes that have not been previously studied in persistent postoperative hypertension with APA. Bioinformatics analysis indicated that differentially expressed genes were associated with lipid metabolic process, metal ion binding, and cell differentiation. Pathway analysis determined that five pathways corresponded to the dysregulated transcripts. The mRNAs-ncRNAs co-expression network was composed of 49 network nodes and 72 connections between 18 coding genes and 31 noncoding genes.

Conclusions:

This study revealed differentially expressed genes in persistent postoperative hypertension with APA and provided a resource of candidate genes for exploration of possible drug targets and prognostic markers.

Prevalence and characterization of somatic mutations in Chinese aldosterone-producing adenoma patients

Recently somatic mutations of KCNJ5, ATP1A1, ATP2B3, and CACNA1D have been identified in patients with aldosterone-producing adenoma (APA). The present study sequenced the DNA in the tissues and blood samples from Chinese patients with APA for KCNJ5, ATP1A1, ATP2B3, and CACNA1D gene mutations.Among the 114 patients, 86 (75.4%) were identified with KCNJ5 somatic mutations, including 3 previously reported (G151R, L168R, T158A) and 2 other unreported mutations. One patient presented with both a point mutation (E147) and an insertion mutation, whereas another had a 36-base duplication, G153_G164dup. No mutation of ATP1A1 and ATP2B3 in the known hotspots was identified and only 1 male patient was detected with a novel CACNA1D mutation, V748I. Unlike other studies, male and female patients had similar KCNJ5 mutation rates (76.9% vs 74.2%). Mutation carriers were younger and had lower preoperative potassium level, whereas male (but not female) mutation carriers had higher preoperative plasma aldosterone concentration and preoperative blood pressures. Mutation carriers also had higher LV mass index (LVMI) than nonmutation carriers. After surgery, LVMI improved significantly in the KCNJ5 mutation group but not in the nonmutation group. The mRNA expression of KCNJ5, CYP11B2, and ATP2B3 was higher in the KCNJ5-mutated APA tissues. Functional characterization of the 2 novel KCNJ5 mutations showed that they were associated with decreased proliferation, membrane depolarization, elevated secretion of aldosterone, and increased expression of CYP11B1 and CYP11B2.In conclusion, Chinese APA patients appear to have a high frequency of somatic KCNJ5 mutation. Mutation prevalence rates are similar among men and women and 2 novel mutations are identified. KCNJ5-mutated patients benefit more from surgical resection of APA than nonmutated patients.

Management of hypertension in primary aldosteronism

Hypertension causes significant morbidity and mortality worldwide, owing to its deleterious effects on the cardiovascular and renal systems. Primary hyperaldosteronism (PA) is the most common cause of reversible hypertension, affecting 5%-18% of adults with hypertension. PA is estimated to result from bilateral adrenal hyperplasia in two-thirds of patients, and from unilateral aldosterone-secreting adenoma in approximately one-third. Suspected cases are initially screened by measurement of the plasma aldosterone-renin-ratio, and may be confirmed by additional noninvasive tests. Localization of aldostosterone hypersecretion is then determined by computed tomography imaging, and in selective cases with adrenal vein sampling. Solitary adenomas are managed by laparoscopic or robotic resection, while bilateral hyperplasia is treated with mineralocorticoid antagonists. Biochemical cure following adrenalectomy occurs in 99% of patients, and hemodynamic improvement is seen in over 90%, prompting a reduction in quantity of anti-hypertensive medications in most patients. End-organ damage secondary to hypertension and excess aldosterone is significantly improved by both surgical and medical treatment, as manifested by decreased left ventricular hypertrophy, arterial stiffness, and proteinuria, highlighting the importance of proper diagnosis and treatment of primary hyperaldosteronism. Although numerous independent predictors of resolution of hypertension after adrenalectomy for unilateral adenomas have been described, the Aldosteronoma Resolution Score is a validated multifactorial model convenient for use in daily clinical practice.