ABSTRACT
This study examined the association of polymorphisms in angiotensin Ⅱ receptor genes (AT1R and AT2R) with the risk for aldosterone-producing adenoma (APA) in a Chinese Han population.Four polymorphisms including rs5182 (573T/C) in exon 4,rs5186 (1166A/C) in 3'-untranslated region (3'-UTR) in AT1R gene and rs5194 (2274G/A) in 3'-UTR,rs1403543 (1675G/A) in intron 1 in AT2R gene were detected in 148 APA patients and 192 normal subjects (serving as control) by using a MGB-Taqman probe.The distribution of genotypes of each locus was in accordance with Hardy-Weinberg Equilibrium (HWE) in the APA and control groups (P＞0.05).The allele A frequency at rs5194 was significantly higher in the APA group (0.49) than in the control group (0.35) (X2=12.08,P=0.001).Subjects with homozygotic genotype AA and heterozygotic genotype GA were at an increased risk for APA as compared to those with GG genotype (OR=2.66,95％ CI=1.45-4.87; OR=1.67,95％ CI=1.02-2.74).Furthermore,rs5194 single-nucleotide polymorphism (SNP) at AT2R gene was significantly associated with APA in additive (OR=1.64,95％ CI=1.21-2.20,P=0.001),dominant (OR=1.94,95％ CI=1.23-3.06,P=0.003),and recessive model (OR=2.01,95％ CI=1.17-3.45,P=0.01).It was concluded that rs5194 polymorphism at AT2R gene was associated with the risk for APA,which may constitute a genetic marker of APA.
ABSTRACT
This study aimed to determine whether aldosterone could induce vascular cell apoptosis in vivo.Thirty-two male rats were randomly divided into 4 groups: vehicle(control),aldosterone,aldosterone plus eplerenone or hydralazine.They were then implanted with an osmotic mini-pump that infused either aldosterone or the vehicle.Systolic blood pressure(SBP)was measured weekly by the tail-cuff method.After 8 weeks,plasma aldosterone concentration(PAC)and renin activity(PRA)were determined by radioimmunoassay.Aortic apoptosis was examined by TUNEL assay.The levels of cytochrome c and caspase-3 were determined by Western blotting and the expression of Bax and Bcl-2 was detected by immnuohistochemistry and Western blotting.The results showed that as compared with control group,aldosterone-infused rats exhibited:(1)an increase in SBP;(2)significantly elevated PAC with depressed PRA;(3)elevated aortic vascular cell apoptosis accompanied with higher levels ofcytochrome c and activated caspase-3; and(4)significantly up-regulated Bax protein with down-regulated Bcl-2.These effects of aldosterone were significantly inhibited after co-administration with eplerenone but not with hydralazine.It was concluded that aldosterone inducedvascular cell apoptosis by its direct effect on the aorta via mineralocorticoid receptors and independently of blood pressure,which may contribute to aldosterone-mediated vascular injury.
ABSTRACT
The expression of angiotensin Ⅱ type 1 receptor(AT1R)and angiotensin Ⅱ type 2 receptor (AT2R)in aldosterone-producing adenoma(APA)of the adrenal gland was detected,and their relationship with clinical indexes of APA was analyzed.The mRNA expression of AT1R and AT2R in50 cases of APA and tissues adjacent to tumors and 12 cases of normal adrenal tissues was detected by using reverse transcriptase polymerase chain reaction(RT-PCR).The expression of AT1R and AT2R proteins in paraffin-embedded slices of tissue was detected by immunohistochemistry.The expression of AT1R in adenoma,tissues adjacent to tumor,and normal tissues of the adrenal gland showed no significant differences.The expression of AT2R in APA tissue was lower than that in normal adrenal gland tissues(P<0.05).Correlation analysis of the mRNA expression level of AT2R and clinical data from patients demonstrated that AT2R expression was negatively related to plasma aldosterone concentration(PAC)(r=-0.467,P<0.05),but positively related with plasma renin activity(PRA)(r=0.604,P<0.05).It is concluded that down-regulation of the AT2R expression is possibly related with the tumorigenesis of APA.