Vitamin D receptor polymorphisms in hypertensive disorders of pregnancy

Hypertension is the most common medical disorder in pregnancy, and a leading cause of maternal and neonatal morbidity and mortality. Vitamin D endocrine system has important influence on immune modulation and endothelial function, which play a role in preeclampsia (PE) and gestational hypertension (GH). Vitamin D receptor (VDR) is present in a large variety of cell types, including placental cells. We examined whether there is an association between VDR polymorphisms (FokI, ApaI and BsmI) with PE or with GH. Restriction fragment length polymorphism techniques were used to genotype 529 pregnant (154 with GH, 162 with PE, and 213 healthy pregnant-HP). VDR haplotype frequencies were inferred using the PHASE 2.1 program. We found similar genotype distributions for the three VDR polymorphisms in both PE and GH groups compared with the HP group (all P > 0.05). In parallel with these findings, the VDR haplotype frequency distribution was similar in both PE and GH groups compared with the HP group (all P > 0.05). Our results showing no significant association between VDR polymorphisms or haplotypes with PE or GH suggest that genetic variations in VDR do not predispose to hypertensive disorders of pregnancy.

Non-invasive brain stimulation for the management of arterial hypertension

The neural control of the cardiovascular system is a complex process that involves many structures at different levels of nervous system. Several cortical areas are involved in the control of systemic blood pressure, such as the sensorimotor cortex, the medial prefrontal cortex and the insular cortex. Non-invasive brain stimulation techniques - repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) - induce sustained and prolonged functional changes of the human cerebral cortex. rTMS and tDCS has led to positive results in the treatment of some neurological and psychiatric disorders. Because experiments in animals show that cortical modulation can be an effective method to regulate the cardiovascular system, non-invasive brain stimulation might be a novel tool in the therapeutics of human arterial hypertension. We here review the experimental evidence that non-invasive brain stimulation can influence the autonomic nervous system and discuss the hypothesis that focal modulation of cortical excitability by rTMS or tDCS can influence sympathetic outflow and, eventually, blood pressure, thus providing a novel therapeutic tool for human arterial hypertension. (C) 2009 Published by Elsevier Ltd.

Effects of Matrix Metalloproteinase (MMP)-2 Polymorphisms on Responsiveness to Antihypertensive Therapy of Women with Hypertensive Disorders of Pregnancy

Imbalanced matrix metalloproteinase (MMP) expression, including MMP-2, has been demonstrated in pre-eclampsia. However, little is known about the effect of polymorphisms in MMP-2 gene on hypertensive disorders of pregnancy. We examined whether two functional MMP-2 polymorphisms (g.-1306C>T and g.-735C>T) are associated with pre-eclampsia and/or gestational hypertension and whether these polymorphisms affect therapeutic responses in women with these conditions. We studied 216 healthy pregnant women (HP), 185 patients with gestational hypertension (GH) and 216 patients with pre-eclampsia (PE). They were stratified as responsive or non-responsive to antihypertensive therapy according to clinical and laboratorial parameters of therapeutic responsiveness. Genomic DNA was extracted from whole blood and genotypes for g-1306C>T and g.-735C>T polymorphisms were determined by real-time PCR using Taqman allele discrimination assays. Haplotype frequencies were inferred using the PHASE 2.1 program. The distributions of MMP-2 genotypes and haplotypes were similar in HP, GH and PE patients (p > 0.05). In addition, we found no significant differences in MMP-2 genotype or haplotype frequencies when GH or PE patients were classified as responsive or non-responsive to antihypertensive therapy (p > 0.05). Our results suggest that MMP-2 polymorphisms do not affect the susceptibility to hypertensive disorders of pregnancy. In parallel, MMP-2 polymorphisms apparently do not affect the responsiveness to antihypertensive therapy of women with these hypertensive disorders of pregnancy.

eNOS Tag SNP Haplotypes in Hypertensive Disorders of Pregnancy

Haplotypes formed by polymorphisms (T-786C, rs2070744; a variable number of tandem repeats in intron 4, and Glu298Asp, rs1799983) of the eNOS gene were associated previously with gestational hypertension (GH) and preeclampsia (PE). However, no study has explored the Tag SNPs rs743506 and rs7830 in these disorders. The aim of the current study was to compare the distribution of the genotypes and haplotypes formed by the five eNOS polymorphisms mentioned among healthy pregnant (HP, n = 122), GH (n = 138), and PE (n = 157). The haplotype formed by "C b G G C" was more frequent in HP compared to GH and PE (p = 0.0071), which is supported by previous findings that demonstrated the association of the combination "C b G" with a higher level of nitrite (NO marker). Our results suggest a protective effect of the haplotype "C b G G C" against the development of hypertensive disorders of pregnancy.

Implications of maternal nutrient restriction in transgenerational programming of hypertension and endothelial dysfunction across F1-F3 offspring

Aims: An extensive variety of prenatal insults are associated with an increased incidence of metabolic and cardiovascular disorders in adult life. We previously demonstrated that maternal global nutrient restriction during pregnancy leads to increased blood pressure and endothelial dysfunction in the adult offspring. This study aimed to assess whether prenatal exposure to nutritional insult has transgenerational effects in F-2 and F-3 offspring. Main methods: For this, female Wistar rats were randomly divided into two groups on day 1 of pregnancy: a control group fed standard chow ad libitum and a restricted group fed 50% of the ad libitum intake throughout gestation. At delivery, all animals were fed a standard laboratory chow diet. At 11 weeks of age, one female and one male from each restricted litter were randomly selected and mated with rats from another restricted litters in order to generate the F-2 offspring. The same procedure produced F-3 generation. Similarly, the rats in the control group were bred for each generation. Key Findings: Our findings show that the deleterious effects of maternal nutrient restriction to which the F-0 mothers were exposed may not be limited to the male first generation. In fact, we found that elevated blood pressure, an impaired vasodilatory response to acetylcholine and alterations in NO production were all transferred to the subsequent males from F-2 and F-3 generations. Significance: Our data show that global nutrient restriction during pregnancy results in a specific phenotype that can be passed transgenerationally to a second and third generation. (c) 2012 Elsevier Inc. All rights reserved.

Matrix metalloproteinase-9 polymorphisms affect plasma MMP-9 levels and antihypertensive therapy responsiveness in hypertensive disorders of pregnancy

Abnormal matrix metalloproteinase (MMP)-9 levels may have a role in hypertensive disorders of pregnancy. We examined whether MMP-9 genetic polymorphisms (g.-1562C>T and g.-90(CA)(13-25)) modify plasma MMP-9 and tissue inhibitor of metalloproteinase (TIMP)-1 levels and the responses to antihypertensive therapy in 214 patients with preeclampsia (PE), 185 patients with gestational hypertension (GH) and a control group of 214 healthy pregnant (HP). Alleles for the g.-90(CA)(13-25) polymorphism were grouped L (low) (<21 CA repeats) or H (high) (>= 21 CA repeats). Plasma MMP-9 and TIMP-1 concentrations were measured by enzyme-linked immunosorbent assay. Plasma MMP-9 concentrations were not affected by genotypes or haplotypes in HP and PE groups, except for the g.-90(CA)(13-25) polymorphism: GH patients with the LH genotype for this polymorphism have higher MMP-9 levels than those with other genotypes. The T allele for the g.-1562C>T polymorphism and the H4 haplotype (combining T and H alleles) are associated with GH and lack of responsiveness to antihypertensive therapy in GH. The H2 haplotype (combining C and H alleles) was associated with lack of responsiveness to antihypertensive therapy in PE, but not in GH. In conclusion, our results show that MMP-9 genetic variants are associated with GH and suggest that MMP-9 haplotypes affect the responsiveness to antihypertensive therapy in hypertensive disorders of pregnancy. The Pharmacogenomics Journal (2012) 12, 489-498; doi: 10.1038/tpj.2011.31; published online 19 July 2011

Expression of angiogenic factors in placenta of stressed rats

The aim of the present study was to analyse the influence of stress on pregnant rats, particularly in terms of maternal, placental and fetal weight, placental morphology and placental gene expression of the angiogenic factors Vegfa and Pgf and their receptors. The parameters were evaluated on gestation Day 20. Maternal, fetal and placental weights were statistically lower in stressed animals than controls, suggesting abnormalities in gestational physiology. Morphologically the placentas of rats subjected to stress were reduced in size and weight, with few glycogen cells and a significant increase in the number of apoptotic cells. Stress caused an increase in placental gene expression of Vegfa (P < 0.05) and a reduction in Pgf, Flt1 and Kdr expression (P < 0.05). It has been suggested that increased VEGF is associated with vasodilatation and hypotension, but in this model persistent hypertension was present. This study suggests that the limited hypotensive Vegfa response to stress-induced hypertension could result from reduced expression of Flt1/Kdr disrupting specific VEGF pathways. These findings may elucidate one of the multiple possible factors underlying how stress modulates placental physiology, and could aid the understanding of stress-induced gestational disorders.

Combined oral contraceptives and increasing cardiovascular risk: thromboembolism and hypertension

Background: Hormonal contraceptive pills are the most used reversible method for familiar planning in Brazil. The combined pill, with synthetic analogs of estrogen and progestin, is employed by 25% of Brazilian female population. Its use provokes an increase of blood pressure levels, takes patient to a hipercoagulability state and predisposes her to thromboembolic events. Purposes: We aimed to describe mechanisms of hypercoagulability promoted by oral combined contraceptives, to analyze the relative risk of cardiovascular events within users and to list the most common circulatory pathologies in these patients. Methods: Three virtual medical databases were surveyed (Pubmed/Medline, BVS/LILACS and Scielo). Twelve studies were selected: clinical trials, case reports and articles of indexed medical periodic originally published in Portuguese and English about synthetic hormones, oral contraception, coagulation disorders and cardiovascular morbimortality. Results: Synthetic estrogen promotes an increase of some clotting factors' levels (VII, VIII, IX, X, XII, XIII and fibrinogen), such as a reduction of their inhibitors (S protein and antithrombin). Because of this, etinilestradiol is the component most related to venous thrombosis and ischemic diseases of brain and heart. It also improves the releasing of hepatic angiotensinogen, taking to a increase of blood pressure levels. Conclusions: The prescription of oral combined contraceptives needs criteria, notably due to adverse effects of etinilestradiol. It is recommended to avoid the administration of these drugs for patients elder than 35 year-old or with risk factors. For these patients, the use of progestagen-only pills seems to be safer.

Epistasis among eNOS, MMP-9 and VEGF maternal genotypes in hypertensive disorders of pregnancy

Polymorphisms of the endothelial nitric oxide synthase (eNOS), matrix metalloproteinase-9 (MMP-9) and vascular endothelial growth factor (VEGF) genes were shown to be associated with hypertensive disorders of pregnancy. However, epistasis is suggested to be an important component of the genetic susceptibility to preeclampsia (PE). The aim of this study was to characterize the interactions among these genes in PE and gestational hypertension (GH). Seven clinically relevant polymorphisms of eNOS (T-786C, rs2070744, a variable number of tandem repeats in intron 4 and Glu298Asp, rs1799983), MMP-9 (C-1562T, rs3918242 and -90(CA)(13-25), rs2234681) and VEGF (C-2578A, rs699947 and G-634C, rs2010963) were genotyped by TaqMan allelic discrimination assays or PCR and fragment separation by electrophoresis in 122 patients with PE, 107 patients with GH and a control group of 102 normotensive pregnant (NP) women. A robust multifactor dimensionality reduction analysis was used to characterize gene-gene interactions. Although no significant genotype combinations were observed for the comparison between the GH and NP groups (P>0.05), the combination of MMP-9-1562CC with VEGF-634GG was more frequent in NP women than in women with PE (P<0.05). Moreover, the combination of MMP-9-1562CC with VEGF-634CC or MMP-9-1562CT with VEGF-634CC or-634GG was more frequent in women with PE than in NP women (P<0.05). These results are obscured when single polymorphisms in these genes are considered and suggest that specific genotype combinations of MMP-9 and VEGF contribute to PE susceptibility. Hypertension Research (2012) 35, 917-921; doi:10.1038/hr.2012.60; published online 10 May 2012

Association between matrix metalloproteinase (MMP)-2 polymorphisms and MMP-2 levels in hypertensive disorders of pregnancy

We examined whether two functional polymorphisms (g.-1306 C> T and g.-735 C>T) in matrix metalloproteinase (MMP)-2 gene are associated with preeclampsia (PE) or gestational hypertension (GH), and whether they modify MMP-2 or tissue inhibitor of metalloproteinase (TIMP)-2 plasma concentrations in these hypertensive disorders of pregnancy. We studied 130 healthy pregnant (HP), 130 pregnant with GH, and 133 pregnant with PE. Genomic DNA was extracted from whole blood and genotypes for g.-1306 C>T and g.-735 C>T polymorphisms were determined by Real Time-PCR, using Taqman allele discrimination assays. Haplotypes were inferred using the PHASE program. Plasma MMP-2 and TIMP-2 concentrations were measured by ELISA. The main findings were that pregnant with PE have higher plasma MMP-2 and TIMP-2 concentrations than HP (P<0.05), although the MMP-2/TIMP-2 ratios were similar (P>0.05). Moreover, pregnant with GH have elevated plasma MMP-2 levels and MMP-2/TIMP-2 ratios compared to HP (P<0.05). While MMP-2 genotypes and haplotypes are not linked with hypertensive disorders of pregnancy, MMP-2 genotypes and haplotypes are associated with significant alterations in plasma MMP-2 and TIMP-2 concentrations in preeclampsia (P<0.05). Our findings may help to understand the relevance of MMP-2 and its genetic polymorphisms to the pathophysiology of hypertensive disorders of pregnancy. It is possible that patients with PE and the MMP-2 haplotype combining the C and T alleles for the g.-1306 C>T and g.-735 C>T polymorphisms may benefit from the use of MMPs inhibitors such as doxycycline. However, this possibility remains to be determined. (C) 2012 Elsevier Inc. All rights reserved.

Maternal iNOS genetic polymorphisms and hypertensive disorders of pregnancy

Increased expression and activity of inducible nitric oxide synthase (iNOS) may contribute to the pathogenesis of pre-eclampsia (PE) and gestational hypertension (GH). However, no previous study has examined whether genetic polymorphisms in the iNOS gene are associated with PE or GH. We examined whether two functional, clinically relevant iNOS genetic polymorphisms (the C(-1026)A polymorphism, rs2779249, in the promoter region, and the G2087A polymorphism, rs2297518, in exon 16) are associated with GH or with PE. We studied 565 pregnant women: 212 healthy pregnant (HP), 166 pregnant with GH and 187 pregnant with PE. Genotypes were determined by real-time PCR, using the Taqman allele discrimination assay. The PHASE 2.1 program was used to estimate haplotype distributions in the three study groups. We found no significant association between the C(-1026)A polymorphism and PE or GH (P>0.05). However, we found the GA genotype and the A allele for the G2087A polymorphism at higher frequency in PE, but not in GH, compared with HP (P<0.05). The haplotype analysis showed no significant intergroup differences (P>0.05). These findings suggest that iNOS genetic variants may affect the susceptibility to PE, but not to GH. Journal of Human Hypertension (2012) 26, 547-552; doi:10.1038/jhh.2011.65; published online 30 June 2011