Association between genetic variation in transforming growth factors beta1 and beta3 and renal dysfunction in non-diabetic Chinese.

Genetic variants of transforming growth factor (TGF) beta1 have been reported to be associated with diabetic nephropathy. Few studies investigated polymorphisms in the TGF-beta1 and TGF-beta3 genes in relation to renal dysfunction in non-diabetic subjects. In all, 601 non-diabetic Chinese were genotyped for the TGF-beta1 T869C and TGF-beta3 IVS3-98G>A polymorphisms by PCR-restriction fragment length polymorphism and real-time allele-specific PCR, respectively. Renal dysfunction was defined as a predicted glomerular filtration rate (GFR) of 60mL/min/1.73m(2) or less. 24-hour urinary albumin excretion was measured by an immunonephelometric assay in 352 hypertensive subjects. Our study sample included 184 (30.6%) women, 396 (65.9%) hypertensive patients (65.9%), and 94 (15.6%) patients with renal dysfunction. In men but not women, the TGF-beta1 TC genotype was significantly (p = 0.0005) overrepresented in patients with renal dysfunction (52.2% vs 36.8% in subjects with normal renal function). Accordingly, in men, with adjustment for age, body mass index, and systolic and diastolic blood pressure, serum creatinine concentration was significantly (p < or = 0.03) higher in the TC heterozygotes than TT and CC homozygotes. Furthermore, in 231 male hypertensive patients, with similar adjustments applied, 24-hour urinary albumin excretion was significantly (p = 0.02) higher in the IVS3-98 AA homozygotes than G allele carriers. In further multivariate regression analysis, only in men, TGF-beta1 and TGF-beta3 genotypes as independent predictors had statistically significant effect on serum creatinine (p = 0.007) and urinary albumin excretion (p = 0.022), respectively. Our study demonstrated the associations of genetic variants in the TGF-beta genes with renal dysfunction and albuminuria in non-diabetic Han Chinese men but not women.

Anthropometric and lifestyle factors associated with white-coat, masked and sustained hypertension in a Chinese population.

OBJECTIVE: We investigated to what extent anthropometric and lifestyle factors contributed to the classification of Chinese individuals into groups with white-coat, masked and sustained hypertension (HT). METHODS: We measured the office and ambulatory blood pressure (BP) in 694 Chinese enrolled in the JingNing population study (45.7% men; mean age, 48.4 years). In multivariate-adjusted analyses, we determined the correlates of both types of BP and the factors contributing to white-coat HT (conventional and daytime BP > or =140/90 and <135/85 mmHg, respectively), masked HT (<140/90 and > or =135/85 mmHg) and sustained HT (> or =140/90 and > or =135/85 mmHg), relative to normotension (<140/90 and <135/85 mmHg). RESULTS: In continuous analyses, the conventional and daytime BPs were positively associated with age, body mass index and urinary sodium, and inversely with urinary potassium. The prevalence of white-coat, masked and sustained HT was 7.8, 10.8, and 35.0%, respectively. In line with the continuous analyses, the risk of sustained hypertension increased with age [odds ratio (OR), 2.11 per 10 years], body mass index (OR, 1.27 per 1 kg/m2) and urinary sodium (OR, 1.18 per 50 mmol/day), but was inversely associated with urinary potassium (OR, 0.34 per 25 mmol/day). Furthermore, the risk of white-coat and masked HT increased with age (OR, 1.79 and 1.40, respectively) and body mass index (OR, 1.14 and 1.12). Women were less likely to have masked hypertension than men (OR, 0.39). CONCLUSIONS: Sex, age, body mass index, and urinary sodium and potassium excretion contribute to the risk of white-coat, masked and sustained HT in Chinese.

Is isolated nocturnal hypertension a novel clinical entity? Findings from a Chinese population study.

We reported previously that normotensive Chinese had higher nighttime diastolic blood pressure compared with non-Chinese. We, therefore, studied the prevalence and characteristics of isolated nocturnal hypertension (HT) and its association with arterial stiffness, an intermediate sign of target organ damage. We recorded ambulatory blood pressure, the central and peripheral systolic augmentation indexes, the ambulatory arterial stiffness index, and brachial-ankle pulse wave velocity in 677 Chinese enrolled in the JingNing population study (53.6% women; mean age: 47.6 years). Prevalence was 10.9% for isolated nocturnal HT (>or=120/70 mm Hg from 10:00 pm to 4:00 am), 4.9% for isolated daytime HT (>or=135/85 mm Hg from 8:00 am to 6:00 pm), and 38.4% for day-night HT. Patients with isolated nocturnal HT, compared with subjects with ambulatory normotension (45.8%), were older (53.7 versus 40.7 years), more often reported alcohol intake (68.9% versus 51.0%), had faster nighttime pulse rate (62.8 versus 60.7 bpm), had higher serum cholesterol (5.12 versus 4.77 mmol/L), and had higher blood glucose (4.84 versus 4.38 mmol/L). Similar to patients with isolated daytime HT or day-night HT, patients with isolated nocturnal HT had higher indexes of arterial stiffness (P<0.05) than subjects with ambulatory normotension (central augmentation index: 140% versus 134%; peripheral augmentation index: 82.6% versus 76.5%; ambulatory arterial stiffness index: 0.40 versus 0.35 U; brachial-ankle pulse wave velocity: 16.2 versus 14.7 m/s). Of 74 patients with isolated nocturnal HT, only 4 (5.4%) had hypertension on conventional office blood pressure measurement (>or=140/90 mm Hg). In conclusion, isolated nocturnal HT can only be diagnosed by ambulatory blood pressure monitoring, is prevalent among Chinese, and is associated with increased arterial stiffness.

Evidence for association of polymorphisms in CYP2J2 and susceptibility to essential hypertension.

OBJECTIVE: Evidence from animal models and human studies suggests that CYP2J2 plays a mechanistic role in the development of hypertension. The present study aims to investigate the potential genetic contribution of the CYP2J2 gene to the etiology of essential hypertension (EH) and individual blood pressure. METHODS: We selected eight polymorphisms in/or around the CYP2J2 gene and performed a case-control association study involving 841 Han Chinese subjects, including 415 unrelated hypertensives and 426 age-, gender- and area-matched normotensives. RESULTS: Three functionally identified variants (CYP2J2 *2, *7 and CYP2J2 *8) and SNP rs11572182 represented rare polymorphisms in Han Chinese. However, the difference in rs1155002 genotype distribution between hypertensive and healthy subjects was close to significance (P = 0.06) in the whole sample. Interestingly, significant evidence for an association with rs1155002 was found in females when stratified by gender. In females, the TT homozygote of rs1155002 seems to be a risk factor for hypertension (p = 0.014). In addition, ANOVA analysis suggested TT carriers had significantly higher systolic blood pressure (p = 0.016). The genotype frequencies for rs10493270, rs1180273 and rs1324491 revealed no statistically significant differences. Likewise, four-marker haplotype frequencies showed no significant differences between cases and controls. CONCLUSION: Our data provide strong evidence that the CYP2J2 gene is a susceptibility factor for essential hypertension, especially in females, and influences individual systolic blood pressure in the Chinese Han population.

[Association of aldosterone synthase gene -344T/C polymorphism with plasma aldosterone and angiotensin II concentration in hypertensive patients].

OBJECTIVE: To investigate the association of aldosterone synthase (CYP11B2) -344T/C polymorphism with plasma renin activity (PRA), and concentrations of angiotensin II (Ang II) and aldosterone (Aldo) in patients with essential hypertension (EH). METHODS: 421 EH patients, 296 males and 125 females, aged 56.3 +/- 11.2, and 207 sex and aged-matched normotensive subjects were genotyped for the CYP11B2 -344T/C polymorphism by polymerase chain reaction-restriction fragment length polymorphism. PRA and plasma Ang II and Aldo concentrations were measured by radioimmunoassay among 328 EH patients in the supine position and 279 of the 328 subjects in the upright position. RESULTS: No significant difference in genotype and allele frequencies of CYP11B2 -344T/C polymorphism was observed between the EH and normotensive subjects (P = 0.61 and P = 0.34 respectively). In the 328 EH patients undergoing measurement of PRA, Ang II, and Aldo, the plasma Aldo concentration of the TT subjects was 76.8 pg/ml, significantly higher than those of the TC subjects (58.8 pg/ml) and CC subjects (58.8 pg/ml, P = 0.02), after adjustment for age, sex and body mass index. No association was found between the -344T/C polymorphism and PRA and plasma Ang II in the supine position (P = 0.63 and P = 0.28 respectively). However, with similar adjustment applied, the plasma Ang II concentration in the upright position was higher in the CC subjects (85.7 pg/ml) than in the TC subjects (54.6 pg/ml) and TT subjects (51.8 pg/ml. P = 0.02). CONCLUSION: In the EH patients, CYP11B2 -344T/C polymorphism is associated with plasma Aldo and the plasma Ang II concentration when the patients are in the upright position.

[Single nucleotide polymorphisms of three candidate genes in essential hypertension].

OBJECTIVE: To explore the association of single nucleotide polymorphisms (SNPs) of three candidate genes, including T869C of transforming growth factor beta1 (TGF-beta1), -344T/C of aldosterone synthase (CYP11B2) and Gly460Trp of alpha-Adducin with essential hypertension in Chinese Han population. METHODS: Three hundred ninety six hypertensive patients and 214 normotensive subjects were genotyped for T869C, -344T/C and Gly460Trp polymorphisms with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and mutagenically separated PCR (MS-PCR), respectively. RESULTS: In single-gene analysis, no association was observed between either CYP11B2 -344T/C or alpha-Adducin Gly460Trp polymorphism and essential hypertension. For female, there were significant difference in genotype distribution and allele frequency of T869C polymorphism (P < 0.02), as compared with subjects with T allele. CC homozygosity had a higher relative risk of hypertension (OR = 2.97, 95% CI, 1.38 to 6.32, P = 0.004), whereas we failed to detect any association between T869C polymorphism and essential hypertension in male. In multiple-gene analysis, the incidence of hypertension was higher in CYP11B2 TT homozygosity than in other CYP11B2 genotypes (OR = 1.99, 95% CI, 1.01 to 3.74, P = 0.03) in the presence of TGF-beta1 CC genotype. CONCLUSIONS: Our results indicated that T869C polymorphism of TGF-beta1 gene might be associated with essential hypertension in female, furthermore, the TGF-beta1 T869C and CYP11B2-344T/C polymorphisms appeared to interact in hypertensive population.

Interaction between body mass index and alcohol intake in relation to blood pressure in HAN and SHE Chinese.

BACKGROUND: Blood pressure (BP) increases with body mass index (BMI) and excessive alcohol intake. Few epidemiologic studies explored the interaction between BMI and alcohol intake in relation to BP. METHODS: We randomly selected 10 villages with a mixed population of HAN and SHE Chinese in the JingNing County in Southeast China. We measured BP, anthropometric characteristics, and alcohol intake in 1688 participants. Our statistical methods included single and multiple linear and logistic regressions. RESULTS: HAN (n = 520) and SHE (n = 1168) had a similar sex and age distribution. SHE Chinese, compared with HAN, had a higher BP (128.0/79.7 v 121.5/76.9 mm Hg, P < .001), and more frequently reported alcohol intake (45.0% v 27.7%; P < .001), but showed lower BMI (22.2 v 22.5 kg/m2; P = .05) and waist-to-hip ratio (0.83 v 0.87; P < .001). In SHE, but not HAN, there was a significant interaction (P < .01) between BMI and alcohol intake in relation to BP. In SHE with BMI < 25 kg/m2, BP was significantly higher in drinkers than nondrinkers (129.4/80.2 v 124.2/77.4 mm Hg, P < .001), whereas among SHE with BMI > or = 25 kg/m2, BP was not associated with alcohol intake (134.3/84.9 v 136.8/85.7 mm Hg, P > .41). Accordingly, in SHE Chinese, the slope of BP associated with BMI was less steep (P < .01) in drinkers than nondrinkers. CONCLUSIONS: Among SHE Chinese, alcohol intake and BMI interactively influenced BP. Further research is required to elucidate the underlying mechanism.

[A polymorphism of kynureninase gene in a hypertensive candidate chromosomal region is associated with essential hypertension].

OBJECTIVE: To identify single nucleotide polymorphisms (SNP) in the regulatory and coding regions of human kynureninase (KYNU) gene in a hypertensive candidate chromosomal region 2q14-q23 of Han Chinese, and to investigate the relationship between polymorphisms in KYNU and essential hypertension. METHODS: The SNPs in the promoter region and exons of the KYNU gene were detected by direct DNA sequencing. Genotyping of the nonsynonymous Lys412Glu (A/G) polymorphism was performed by DHPLC technology in 456 hypertensive patients and 430 normal controls. RESULTS: Sixteen SNP were identified in the KYNU gene, including 6 in the regulatory region and 2 in the coding region (both of them lead to substitution of amino acid). Significant differences between hypertensive patients and normal controls were observed for the distribution of alleles (chi(2) = 6.693, P = 0.035) and genotypes (chi(2) = 4.188, P = 0.041) of the Lys412Glu polymorphism in all subjects, and for the distribution of alleles in the subgroup of men (chi(2) = 4.424, P = 0.035). CONCLUSION: The Lys412Glu polymorphism of the KYNU gene in a hypertensive candidate chromosomal region is associated with essential hypertension in Han Chinese.

[Association of peripheral and central blood pressure with the alpha-adducin Gly460Trp polymorphism in a Chinese population].

OBJECTIVE: To investigate the association of peripheral and central blood pressure with the alpha-adducin Gly460Trp polymorphism in Chinese. METHODS: We randomly selected 6 villages from JingNing County, ZheJiang Province. We invited nuclear families to take part in our study. We measured each participant's blood pressure at the non-dominant arm by means of a standard mercury sphygmomanometer at subjects' homes. Five consecutive readings were averaged for analysis. Central blood pressures were obtained by use of SphigmoCor pulse wave analysis system. The observers administered a standardized questionnaire to collect information on smoking habits, alcohol consumption and use of antihypertensive drugs. Venous blood was sampled and the adducin genotype was determined by restrictive fragment length polymorphism (RFLP). RESULTS: Four hundred and forty-two subjects included 230 (52.0%) women, and 116 (26.2%) hypertensive patients, of whom 49 (11.1%) took antihypertensive drugs. The frequencies of alpha -adducin GlyGly, GlyTrp and TrpTrp genotypes were 21.3%, 54.5% and 24.2%, respectively. There was no association between the alpha-adducin Gly460Trp polymorphism and peripheral systolic and diastolic blood pressure and pulse pressure. However, both before and after adjustment for sex, age, age(2), body-mass index, current smoking, alcohol intake, and antihypertensive treatment, the alpha-adducin polymorphism was significantly (P < 0.02) associated with central systolic blood pressure and central pulse pressure. After adjustment, central systolic blood pressure (+/- SE) averaged 122.5 +/- 3.5, 114.1 +/- 1.5 and 109.1 +/- 1.8 mm Hg (P = 0.01) in the GlyGly, GlyTrp and TrpTrp subjects, respectively. The corresponding values for central pulse pressure were 39.4 +/- 1.3, 36.4 +/- 1.0 and 32.9 +/- 0.9 mm Hg (P = 0.002), respectively. CONCLUSIONS: In the JingNing population, the adducin 460Trp allele was associated with lower levels of central systolic pressure and pulse pressure.

[No association between 3 polymorphisms of transforming growth factor beta3 gene and essential hypertension in Chinese].

OBJECTIVE: To investigate possible association between the single nucleotide polymorphisms (SNPs) of transforming growth factor beta3 (TGF-beta3) gene and essential hypertension (EH) in Chinese. METHODS: The promoter region, exons, as well as part of the introns of TGF-beta3 gene were sequenced by a fluorescent labeling automatic sequencing method to detect and characterize the SNPs in 24 DNA samples from a Chinese population. Then we conducted a case-control study using 396 patients with hypertension (case) and 214 nomortensive subjects (control). The three SNPs including Thr63Asn, SS5608219 and SS5608220 were genotyped by PCR-RFLP or real-time allele-specific PCR in subjects studied. RESULTS: Seven SNPs in the exons, introns and 3'untranslated region (3'UTR) of TGF-beta3 gene were identified. Among them, 2 SNPs were found to be novel genetic variants and one of the two located in the exon 1 and produced substitution of amino acid. However, no differences were found between hypertensives and nomortensives in genotype distribution and allele frequency of SS5608219, Thr63Asn or SS5608220 polymorphisms. CONCLUSIONS: Two novel SNPs of TGF-beta3 gene were identified in Chinese. One of them produces a threonine to asparagines substitution in codon 63 (Thr63Asn). But no association was found between TGF-beta3 gene polymorphisms and EH in Chinese.

Family-based associations between the angiotensin- converting enzyme insertion/deletion polymorphism and multiple cardiovascular risk factors in Chinese.

OBJECTIVE: We investigated, in a sample of Chinese families, the associations of body mass index (BMI), blood pressure (BP), serum lipids, fasting plasma glucose, serum creatinine and uric acid with the insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene. METHODS: We genotyped 902 subjects from 186 nuclear families recruited in Shanghai, China, via a specialized hypertension clinic. We performed family-based association analyses for continuous and dichotomous phenotypic measurements using the quantitative and sib- transmission/disequilibrium tests (QTDT and Sib-TDT), respectively. RESULTS: The study sample included 121 parents and 781 offspring from 25 two-parent families, 71 one-parent families, and 90 families without parental information. The median number of offspring was four (range from 2 to 10). Of the 654 (85.4%) hypertensive offspring, 458 took antihypertensive drugs. The 354 male offspring were slightly younger than the 427 female siblings (48.1 versus 49.2 years, P = 0.03), but they had similar BMI (25.1 kg/m). In 482 informative offspring, QTDT analyses demonstrated a significant association between BMI and the transmission of the ACE D allele (regression coefficient 0.563, chi 2 = 4.02, P = 0.04). In 106 families with at least one hypertensive offspring and at least one normotensive sibling, Sib-TDT analyses showed that the ACE D allele was slightly over-transmitted from heterozygous parents to hypertensive offspring (P = 0.08). CONCLUSIONS: Our family-based study suggests that in Chinese, the ACE I/D polymorphism might play a role in the development of obesity and hypertension, which are closely linked cardiovascular risk factors.

[Association of single nucleotide polymorphism in human SCN7A gene with essential hypertension in Chinese].

OBJECTIVE: To identify the single nucleotide polymorphisms (SNPs) in the regulatory and coding regions of human SCN7A (sodium channel, voltage-gated, type VII, alpha polypeptide) gene and to investigate the association of some of these SNPs with essential hypertension (EH) in Chinese. METHODS: The promoter region, exons, as well as part of the introns of SCN7A gene were sequenced by a fluorescent labeling automatic sequencing method to identify and characterize the SNPs in Chinese population. SNP genotyping was performed by PCR-RFLP or direct DNA sequencing in unrelated EH patients and normotensive controls from a Chinese Han population residing in Shanghai area. Case-control studies on seven SNPs were first carried out in 96 patients and 96 normotensive controls. The positive finding was further verified in an extended study containing 288 patients and 288 controls. RESULTS: Thirty-two SNPs were identified through a 13,132 bp sequencing of SCN7A gene. Among them, seven were in regulatory region, ten in coding regions, one in 3'UTR and fourteen in introns. Thirty SNPs were novel SNPs, and a cSNP in exon 18 (SNP021) was associated with hypertension. CONCLUSION: The SNP021 in the gene SCN7A is associated with essential hypertension of Chinese Han population in Shanghai and the role of SCN7A gene in hypertension deserves to be further analyzed.

[Activation of nucleus-independent signals triggered by N-methyl-N'-nitro-N- nitrosoguanidine].

OBJECTIVE: To study the effect of MNNG on inducement of non-targeted mutation and activation of several cellular signal transduction pathways, and to determine whether the activation of these signaling pathways was dependent on the DNA-damage. METHODS: Vero cells were enucleated by discontinuous density centrifugation. The PKA activities were measured by enzyme-linked immunosorbent assay. The status of cell membrane receptors was studied with immunofluorescent staining and confocal microscopy. RESULT: In enucleated cytoplasts, MNNG-treatment increased PKA activity for about 2.3-fold in accordance with the 2.7-fold up-regulation of PKA activity in whole vero cells exposed to MNNG. The clustering of cell surface receptors of epidermal growth factor and tumor necrosis factor alpha was also observed in cells exposed to MNNG; this phenomenon was also found in enucleated cells. CONCLUSION: The results indicate that the initiation of signal cascades induced by low concentration of MNNG might be associated with its interaction with cell surface receptors and/or direct activation of related signal proteins but not its DNA damage.

[Activation of transcription factors induced by low concentration of N-methyl-N'-nitro-N-nitrosoguanidine].

OBJECTIVE: To investigate the effect of MNNG on some of the transcription factors such as NF- kappaB, CREB, AP-1 and c-Myc. METHODS: The activities of these transcription factors were measured by transient transfection assay of SEAP vectors. RESULT: The expressions of AP-1, CREB and NF- kappaB driven reporter genes were elevated for about 1.3, 1.4 and 1.3 times in MNNG-treated cells, respectively, as compared to untreated controls. However, the exposure of MNNG had no effect on the activity of c-Myc. CONCLUSION: The activation of certain transcription factors might be involved in the process of untargeted mutation induced by low concentration of MNNG treatment.

Angiotensin II type 2 receptor gene polymorphisms and essential hypertension.

AIM: To identify the genetic variants of angiotensin II type 2 receptor (AT2R) gene in a Chinese population and to determine whether the AT2R gene polymorphisms are associated with essential hypertension (EH). METHODS: The detection of single nucleotide polymorphisms (SNPs) was performed in 19 subjects by a direct DNA sequencing. Two hundred fifty patients with EH and 250 nomortensive controls were included in the study to assess the contribution of polymorphism of AT2R gene to hypertension. RESULTS: We identified 9 SNPs in the promoter, intron, exons and 3' untranslated region (3'UTR) of AT2R gene; among them 5 SNPs were novel molecular variants. A case-control study using a most frequent SNP (1334T/C) in the promoter region, showed a significant increase in allele frequency of C1334 in male hypertensive subjects (17.5 % vs 10.3 % for normotensive subjects, P<0.05). CONCLUSION: The catalogue of SNPs of AT2R gene in Chinese population showed ethnic difference in DNA sequence variation. A polymorphism in the promoter region (1334T/C) of AT2R gene might be involved in the development of hypertension in Chinese population.

Relation of renin-angiotensin system gene polymorphisms and expressions with the efficacy of antihypertensive drugs.

OBJECTIVE: To investigate the relation of renin-angiotensin system (RA3) gene polymorphisms and expressions with the clinical efficacy of antihypertensive drugs. METHODS: This randomized, single-blind study consisted of 90 patients with essential hypertension, who were divided into losartan, lisinopril and nisodipine groups with corresponding medications as indicated. The genotypes of angiotensin-converting enzyme (ACE) insertion/deletion, angiotensinogen (AGT) M235T polymorphism and expressions of ACE and AT1 receptor genes were examined individually. RESULTS: The basal level of mRNA expression of AT1 receptor was lower in patients with MM genotype of AGT gene than those in patients with MT 1 and TT genotypes, but between the latter two, no significant differences were found. The three antihypertensive drugs, when significantly lowering the blood pressure, reduced AT1 receptor mRNA expression concurrently. Losartan and lisinopril both decreased ACE mRNA expression levels that were positively correlated with the difference of the diastolic blood pressure whereas nisodipine elevated ACE mRNA expression, showing inverse correlation to the difference of thediastolic blood pressure. CONCLUSION: For patients with hypertension who have elevated basal levels of AT1 mRNA expression and AGT T allele or who retain high basal expression levels of ACE mRNA AT1 antagonists and ACE inhibitors that execute their action through RAS are preferentially selected, and in cases of low basal levels of ACE mRNA calcium antagonists are preferred.