Defective peroxisomal proliferators activated receptor gamma activity due to dominant-negative mutation synergizes with hypertension to accelerate cardiac fibrosis in mice

Aims: Humans with inactivating mutations in peroxisomal proliferators activated receptor gamma (PPAR?) typically develop a complex metabolic syndrome characterized by insulin resistance, diabetes, lipodystrophy, hypertension, and dyslipidaemia which is likely to increase their cardiovascular risk. Despite evidence that the activation of PPAR? may prevent cardiac fibrosis and hypertrophy, recent evidence has suggested that pharmacological activation of PPAR? causes increased cardiovascular mortality. In this study, we investigated the effects of defective PPAR? function on the development of cardiac fibrosis and hypertrophy in a murine model carrying a human dominant-negative mutation in PPAR?. Methods and results: Mice with a dominant-negative point mutation in PPAR? (P465L) and their wild-type (WT) littermates were treated with either subcutaneous angiotensin II (AngII) infusion or saline for 2 weeks. Heterozygous P465L and WT mice developed a similar increase in systolic blood pressure, but the mutant mice developed significantly more severe cardiac fibrosis to AngII that correlated with increased expression of profibrotic genes. Both groups similarly increased the heart weight to body weight ratio compared with saline-treated controls. There were no differences in fibrosis between saline-treated WT and P465L mice. Conclusion: These results show synergistic pathogenic effects between the presence of defective PPAR? and AngII-induced hypertension and suggest that patients with PPAR? mutation and hypertension may need more aggressive therapeutic measures to reduce the risk of accelerated cardiac fibrosis. © The Author 2009.

Maternal low-protein diet during mouse pre-implantation development induces vascular dysfunction and altered renin-angiotensin-system homeostasis in the offspring

Environmental perturbations during early mammalian development can affect aspects of offspring growth and cardiovascular health. We have demonstrated previously that maternal gestational dietary protein restriction in mice significantly elevated adult offspring systolic blood pressure. Therefore, the present study investigates the key mechanisms of blood pressure regulation in these mice. Following mating, female MF-1 mice were assigned to either a normal-protein diet (NPD; 18% casein) or an isocaloric low-protein diet throughout gestation (LPD; 9% casein), or fed the LPD exclusively during the pre-implantation period (3.5d) before returning to the NPD for the remainder of gestation (Emb-LPD). All offspring received standard chow. At 22 weeks, isolated mesenteric arteries from LPD and Emb-LPD males displayed significantly attenuated vasodilatation to isoprenaline (P=0.04 and P=0.025, respectively), when compared with NPD arteries. At 28 weeks, stereological analysis of glomerular number in female left kidneys revealed no significant difference between the groups. Real-time RT-PCR analysis of type 1a angiotensin II receptor, Na /K ATPase transporter subunits and glucocorticoid receptor expression in male and female left kidneys revealed no significant differences between the groups. LPD females displayed elevated serum angiotensin-converting enzyme (ACE) activity (P=0.044), whilst Emb-LPD males had elevated lung ACE activity (P=0.001), when compared with NPD offspring. These data demonstrate that elevated offspring systolic blood pressure following maternal gestational protein undernutrition is associated with impaired arterial vasodilatation in male offspring, elevated serum and lung ACE activity in female and male offspring, respectively, but kidney glomerular number in females and kidney gene expression in male and female offspring appear unaffected. © 2010 The Authors.

Angiotensin II induces soluble fms-Like tyrosine kinase-1 release via calcineurin signaling pathway in pregnancy

Maternal endothelial dysfunction in preeclampsia is associated with increased soluble fms-like tyrosine kinase-1 (sFlt-1), a circulating antagonist of vascular endothelial growth factor and placental growth factor. Angiotensin II (Ang II) is a potent vasoconstrictor that increases concomitant with sFlt-1 during pregnancy. Therefore, we speculated that Ang II may promote the expression of sFlt-1 in pregnancy. Here we report that infusion of Ang II significantly increases circulating levels of sFlt-1 in pregnant mice, thereby demonstrating that Ang II is a regulator of sFlt-1 secretion in vivo. Furthermore, Ang II stimulated sFlt-1 production in a dose- and time-dependent manner from human villous explants and cultured trophoblasts but not from endothelial cells, suggesting that trophoblasts are the primary source of sFlt-1 during pregnancy. As expected, Ang II-induced sFlt-1 secretion resulted in the inhibition of endothelial cell migration and in vitro tube formation. In vitro and in vivo studies with losartan, small interfering RNA specific for calcineurin and FK506 demonstrated that Ang II-mediated sFlt-1 release was via Ang II type 1 receptor activation and calcineurin signaling, respectively. These findings reveal a previously unrecognized regulatory role for Ang II on sFlt-1 expression in murine and human pregnancy and suggest that elevated sFlt-1 levels in preeclampsia may be caused by a dysregulation of the local renin/angiotensin system.

Angiotensin receptors and β-catenin regulate brain endothelial integrity in malaria

Cerebral malaria is characterized by cytoadhesion of Plasmodium falciparum–infected red blood cells (Pf-iRBCs) to endothelial cells in the brain, disruption of the blood-brain barrier, and cerebral microhemorrhages. No available antimalarial drugs specifically target the endothelial disruptions underlying this complication, which is responsible for the majority of malaria-associated deaths. Here, we have demonstrated that ruptured Pf-iRBCs induce activation of β-catenin, leading to disruption of inter–endothelial cell junctions in human brain microvascular endothelial cells (HBMECs). Inhibition of β-catenin–induced TCF/LEF transcription in the nucleus of HBMECs prevented the disruption of endothelial junctions, confirming that β-catenin is a key mediator of P. falciparum adverse effects on endothelial integrity. Blockade of the angiotensin II type 1 receptor (AT1) or stimulation of the type 2 receptor (AT2) abrogated Pf-iRBC–induced activation of β-catenin and prevented the disruption of HBMEC monolayers. In a mouse model of cerebral malaria, modulation of angiotensin II receptors produced similar effects, leading to protection against cerebral malaria, reduced cerebral hemorrhages, and increased survival. In contrast, AT2-deficient mice were more susceptible to cerebral malaria. The interrelation of the β-catenin and the angiotensin II signaling pathways opens immediate host-targeted therapeutic possibilities for cerebral malaria and other diseases in which brain endothelial integrity is compromised.

Investigating Angiotensin II in cardiac remodelling and the counter-regulatory actions of Angiotensin-(1-9)

Cardiovascular diseases (CVDs) including, hypertension, coronary heart disease and heart failure are the leading cause of death worldwide. Hypertension, a chronic increase in blood pressure above 140/90 mmHg, is the single main contributor to deaths due to heart disease and stroke. In the heart, hypertension results in adaptive cardiac remodelling, including LV hypertrophy to normalize wall stress and maintain cardiac contractile function. However, chronic increases in BP results in the development of hypertensive heart disease (HHD). HHD describes the maladaptive changes during cardiac remodelling which result in reduced systolic and diastolic function and eventually heart failure. This includes ventricular dilation due to eccentric hypertrophy, cardiac fibrosis which stiffens the ventricular wall and microvascular rarefaction resulting in a decrease in coronary blood flow albeit an increase in energy demand. Chronic activation of the renin-angiotensin-system (RAS) with its effector peptide angiotensin (Ang)II plays a key role in the development of hypertension and the maladaptive changes in HHD. Ang II acts via the angiotensin type 1 receptor (AT1R) to mediate most of its pathological actions during HHD, including stimulation of cardiomyocyte hypertrophy, activation of cardiac fibroblasts and increased collagen deposition. The counter-regulatory axis of the RAS which is centred on the ACE2/Ang-(1-7)/Mas axis has been demonstrated to counteract the pathological actions of Ang II in the heart and vasculature. Ang-(1-7) via the Mas receptor prevents Ang II-induced cardiac hypertrophy and fibrosis and improves cardiac contractile function in animal models of HHD. In contrast, less is known about Ang-(1-9) although evidence has demonstrated that Ang-(1-9) also antagonises Ang II and is anti-hypertrophic and anti-fibrotic in animal models of acute cardiac remodelling. However, so far it is not well documented whether Ang-(1-9) can reverse established cardiac dysfunction and remodelling and whether it is beneficial when administered chronically. Therefore, the main aim of this thesis was to assess the effects of chronic Ang-(1-9) administration on cardiac structure and function in a model of Ang II-induced cardiac remodelling. Furthermore, this thesis aimed to investigate novel pathways contributing to the pathological remodelling in response to Ang II. First, a mouse model of chronic Ang II infusion was established and characterised by comparing the structural and functional effects of the infusion of a low and high dose of Ang II after 6 weeks. Echocardiographic measurements demonstrated that low dose Ang II infusion resulted in a gradual decline in cardiac function while a high dose of Ang II induced acute cardiac contractile dysfunction. Both doses equally induced the development of cardiac hypertrophy and cardiac fibrosis characterised by an increase in the deposition of collagen I and collagen III. Moreover, increases in gene expression of fibrotic and hypertrophic markers could be detected following high dose Ang II infusion over 6 weeks. Following this characterisation, the high dose infusion model was used to assess the effects of Ang-(1-9) on cardiac structural and functional remodelling in established disease. Initially, it was evaluated whether Ang-(1-9) can reverse Ang II-induced cardiac disease by administering Ang-(1-9) for 2-4 weeks following an initial 2 week infusion of a high dose of Ang II to induce cardiac contractile dysfunction. The infusion of Ang-(1-9) for 2 weeks was associated with a significant improvement of LV fractional shortening compared to Ang II infusion. However, after 4 weeks fractional shortening declined to Ang II levels. Despite the transient improvement in cardiac contractile function, Ang-(1-9) did not modulate blood pressure, LV hypertrophy or cardiac fibrosis. To further investigate the direct cardiac effects of Ang-(1-9), cardiac contractile performance in response to Ang-(1-9) was evaluated in the isolated Langendorff-perfused rat heart. Perfusion of Ang-(1-9) in the paced and spontaneously beating rat heart mediated a positive inotropic effect characterised by an increase in LV developed pressure, cardiac contractility and relaxation. This was in contrast to Ang II and Ang-(1-7). Furthermore, the positive inotropic effect to Ang-(1-9) was blocked by the AT1R antagonist losartan and the protein kinase A inhibitor H89. Next, endothelial-to-mesenchymal transition (EndMT) as a novel pathway that may contribute to Ang II-induced cardiac remodelling was assessed in Ang II-infused mice in vivo and in human coronary artery endothelial cells (HCAEC) in vitro. Infusion of Ang II to mice for 2-6 weeks resulted in a significant decrease in myocardial capillary density and this was associated with the occurrence of dual labelling of endothelial cells for endothelial and mesenchymal markers. In vitro stimulation of HCAEC with TGFβ and Ang II revealed that Ang II exacerbated TGF-induced gene expression of mesenchymal markers. This was not correlated with any changes in SMAD2 or ERK1/2 phosphorylation with co-stimulation of TGFβ and Ang II. However, superoxide production was significantly increased in HCAEC stimulated with Ang II but not TGFβ. Finally, the role of Ang II in microvesicle (MV)-mediated cardiomyocyte hypertrophy was investigated. MVs purified from neonatal rat cardiac fibroblasts were found to contain detectable Ang II and this was increased by stimulation of fibroblasts with Ang II. Treatment of cardiomyocytes with MVs derived from Ang II-stimulated fibroblasts induced cardiomyocyte hypertrophy which could be blocked by the AT1R antagonist losartan and an inhibitor of MV synthesis and release brefeldin A. Furthermore, Ang II was found to be present in MVs isolated from serum and plasma of Ang II-infused mice and SHRSP and WKY rats. Overall, the findings of this thesis demonstrate for the first time that the actions of Ang-(1-9) in cardiac pathology are dependent on its time of administration and that Ang-(1-9) can reverse Ang II-induced cardiac contractile dysfunction by acting as a positive inotrope. Furthermore, this thesis demonstrates evidence for an involvement of EndMT and MV signalling as novel pathways contributing to Ang II-induced cardiac fibrosis and hypertrophy, respectively. These findings provide incentive to further investigate the therapeutic potential of Ang-(1-9) in the treatment of cardiac contractile dysfunction in heart disease, establish the importance of novel pathways in Ang II-mediated cardiac remodelling and evaluate the significance of the presence of Ang II in plasma-derived MVs.

Impaired Compensatory Beta-cell Function And Growth In Response To High-fat Diet In Ldl Receptor Knockout Mice.

In this study, we investigated the effect of low density lipoprotein receptor (LDLr) deficiency on gap junctional connexin 36 (Cx36) islet content and on the functional and growth response of pancreatic beta-cells in C57BL/6 mice fed a high-fat (HF) diet. After 60 days on regular or HF diet, the metabolic state and morphometric islet parameters of wild-type (WT) and LDLr-/- mice were assessed. HF diet-fed WT animals became obese and hypercholesterolaemic as well as hyperglycaemic, hyperinsulinaemic, glucose intolerant and insulin resistant, characterizing them as prediabetic. Also they showed a significant decrease in beta-cell secretory response to glucose. Overall, LDLr-/- mice displayed greater susceptibility to HF diet as judged by their marked cholesterolaemia, intolerance to glucose and pronounced decrease in glucose-stimulated insulin secretion. HF diet induced similarly in WT and LDLr-/- mice, a significant decrease in Cx36 beta-cell content as revealed by immunoblotting. Prediabetic WT mice displayed marked increase in beta-cell mass mainly due to beta-cell hypertrophy/replication. Nevertheless, HF diet-fed LDLr-/- mice showed no significant changes in beta-cell mass, but lower islet-duct association (neogenesis) and higher beta-cell apoptosis index were seen as compared to controls. The higher metabolic susceptibility to HF diet of LDLr-/- mice may be explained by a deficiency in insulin secretory response to glucose associated with lack of compensatory beta-cell expansion.

Blockade Of Renin-angiotensin System Prevents Micturition Dysfunction In Renovascular Hypertensive Rats.

Association between hypertension and bladder symptoms has been described. We hypothesized that micturition dysfunction may be associated with renin-angiotensin system (RAS) acting in urethra. The effects of the anti-hypertensive drugs losartan (AT1 antagonist) and captopril (angiotensin-converting enzyme inhibitor) in comparison with atenolol (β1-adrenoceptor antagonist independently of RAS blockade) have been investigated in bladder and urethral dysfunctions during renovascular hypertension in rats. Two kidney-1 clip (2K-1C) rats were treated with losartan (30 mg/kg/day), captopril (50mg/kg/day) or atenolol (90 mg/kg/day) for eight weeks. Cystometric study, bladder and urethra smooth muscle reactivities, measurement of cAMP levels and p38 MAPK phosphorylation in urinary tract were determined. Losartan and captopril markedly reduced blood pressure in 2K-1C rats. The increases in non-voiding contractions, voiding frequency and bladder capacity in 2K-1C rats were prevented by treatments with both drugs. Likewise, losartan and captopril prevented the enhanced bladder contractions to electrical-field stimulation (EFS) and carbachol, along with the impaired relaxations to β-adrenergic-cAMP stimulation. Enhanced neurogenic contractions and impaired nitrergic relaxations were observed in urethra from 2K-1C rats. Angiotensin II also produced greater urethral contractions that were accompanied by higher phosphorylation of p38 MAPK in urethral tissues of 2K-1C rats. Losartan and captopril normalized the urethral dysfunctions in 2K-1C rats. In contrast, atenolol treatment largely reduced the blood pressure in 2K-1C rats but failed to affect the urinary tract smooth muscle dysfunction. The urinary tract smooth muscle dysfunction in 2K-1C rats takes place by local RAS activation irrespective of levels of arterial blood pressure.

Peripheral P2x7 Receptor-induced Mechanical Hyperalgesia Is Mediated By Bradykinin.

P2X7 receptors play an important role in inflammatory hyperalgesia, but the mechanisms involved in their hyperalgesic role are not completely understood. In this study, we hypothesized that P2X7 receptor activation induces mechanical hyperalgesia via the inflammatory mediators bradykinin, sympathomimetic amines, prostaglandin E2 (PGE2), and pro-inflammatory cytokines and via neutrophil migration in rats. We found that 2'(3')-O-(4-benzoylbenzoyl)adenosine 5'-triphosphate triethylammonium salt (BzATP), the most potent P2X7 receptor agonist available, induced a dose-dependent mechanical hyperalgesia that was blocked by the P2X7 receptor-selective antagonist A-438079 but unaffected by the P2X1,3,2/3 receptor antagonist TNP-ATP. These findings confirm that, although BzATP also acts at both P2X1 and P2X3 receptors, BzATP-induced hyperalgesia was mediated only by P2X7 receptor activation. Co-administration of selective antagonists of bradykinin B1 (Des-Arg(8)-Leu(9)-BK (DALBK)) or B2 receptors (bradyzide), β1 (atenolol) or β2 adrenoceptors (ICI 118,551), or local pre-treatment with the cyclooxygenase inhibitor indomethacin or the nonspecific selectin inhibitor fucoidan each significantly reduced BzATP-induced mechanical hyperalgesia in the rat hind paw. BzATP also induced the release of the pro-inflammatory cytokines tumor necrosis factor α (TNF-α), interleukin (IL)-1β, IL-6 and cytokine-induced neutrophil chemoattractant-1 (CINC-1), an effect that was significantly reduced by A-438079. Co-administration of DALBK or bradyzide with BzATP significantly reduced BzATP-induced IL-1β and CINC-1 release. These results indicate that peripheral P2X7 receptor activation induces mechanical hyperalgesia via inflammatory mediators, especially bradykinin, which may contribute to pro-inflammatory cytokine release. These pro-inflammatory cytokines in turn may mediate the contributions of PGE2, sympathomimetic amines and neutrophil migration to the mechanical hyperalgesia induced by local P2X7 receptor activation.

Icatibant, An Inhibitor Of Bradykinin Receptor 2, For Hereditary Angioedema Attacks: Prospective Experimental Single-cohort Study.

Hereditary angioedema (HAE) with C1 inhibitor deficiency manifests as recurrent episodes of edema involving the skin, upper respiratory tract and gastrointestinal tract. It can be lethal due to asphyxia. The aim here was to evaluate the response to therapy for these attacks using icatibant, an inhibitor of the bradykinin receptor, which was recently introduced into Brazil. Prospective experimental single-cohort study on the efficacy and safety of icatibant for HAE patients. Patients with a confirmed HAE diagnosis were enrolled according to symptoms and regardless of the time since onset of the attack. Icatibant was administered in accordance with the protocol that has been approved in Brazil. Symptom severity was assessed continuously and adverse events were monitored. 24 attacks in 20 HAE patients were treated (female/male 19:1; 19-55 years; median 29 years of age). The symptoms were: subcutaneous edema (22/24); abdominal pain (15/24) and upper airway obstruction (10/24). The time taken until onset of relief was: 5-10 minutes (5/24; 20.8%); 10-20 (5/24; 20.8%); 20-30 (8/24; 33.4%); 30-60 (5/24; 20.8%); and 2 hours (1/24; 4.3%). The time taken for complete resolution of symptoms ranged from 4.3 to 33.4 hours. Adverse effects were only reported at injection sites. Mild to moderate erythema and/or feelings of burning were reported by 15/24 patients, itching by 3 and no adverse effects in 6. HAE type I patients who received icatibant responded promptly; most achieved improved symptom severity within 30 minutes. Local adverse events occurred in 75% of the patients.

The Analgesic Effect Of Dipyrone In Peripheral Tissue Involves Two Different Mechanisms: Neuronal K(atp) Channel Opening And Cb(1) Receptor Activation.

Dipyrone (metamizole) is an analgesic pro-drug used to control moderate pain. It is metabolized in two major bioactive metabolites: 4-methylaminoantipyrine (4-MAA) and 4-aminoantipyrine (4-AA). The aim of this study was to investigate the participation of peripheral CB1 and CB2 cannabinoid receptors activation in the anti-hyperalgesic effect of dipyrone, 4-MAA or 4-AA. PGE2 (100ng/50µL/paw) was locally administered in the hindpaw of male Wistar rats, and the mechanical nociceptive threshold was quantified by electronic von Frey test, before and 3h after its injection. Dipyrone, 4-MAA or 4-AA was administered 30min before the von Frey test. The selective CB1 receptor antagonist AM251, CB2 receptor antagonist AM630, cGMP inhibitor ODQ or KATP channel blocker glibenclamide were administered 30min before dipyrone, 4-MAA or 4-AA. The antisense-ODN against CB1 receptor expression was intrathecally administered once a day during four consecutive days. PGE2-induced mechanical hyperalgesia was inhibited by dipyrone, 4-MAA, and 4-AA in a dose-response manner. AM251 or ODN anti-sense against neuronal CB1 receptor, but not AM630, reversed the anti-hyperalgesic effect mediated by 4-AA, but not by dipyrone or 4-MAA. On the other hand, the anti-hyperalgesic effect of dipyrone or 4-MAA was reversed by glibenclamide or ODQ. These results suggest that the activation of neuronal CB1, but not CB2 receptor, in peripheral tissue is involved in the anti-hyperalgesic effect of 4-aminoantipyrine. In addition, 4-methylaminoantipyrine mediates the anti-hyperalgesic effect by cGMP activation and KATP opening.

Toll-like Receptor 4 Activation Promotes Cardiac Arrhythmias By Decreasing The Transient Outward Potassium Current (ito) Through An Irf3-dependent And Myd88-independent Pathway.

Cardiac arrhythmias are one of the main causes of death worldwide. Several studies have shown that inflammation plays a key role in different cardiac diseases and Toll-like receptors (TLRs) seem to be involved in cardiac complications. In the present study, we investigated whether the activation of TLR4 induces cardiac electrical remodeling and arrhythmias, and the signaling pathway involved in these effects. Membrane potential was recorded in Wistar rat ventricle. Ca(2+) transients, as well as the L-type Ca(2+) current (ICaL) and the transient outward K(+) current (Ito), were recorded in isolated myocytes after 24 h exposure to the TLR4 agonist, lipopolysaccharide (LPS, 1 μg/ml). TLR4 stimulation in vitro promoted a cardiac electrical remodeling that leads to action potential prolongation associated with arrhythmic events, such as delayed afterdepolarization and triggered activity. After 24 h LPS incubation, Ito amplitude, as well as Kv4.3 and KChIP2 mRNA levels were reduced. The Ito decrease by LPS was prevented by inhibition of interferon regulatory factor 3 (IRF3), but not by inhibition of interleukin-1 receptor-associated kinase 4 (IRAK4) or nuclear factor kappa B (NF-κB). Extrasystolic activity was present in 25% of the cells, but apart from that, Ca(2+) transients and ICaL were not affected by LPS; however, Na(+)/Ca(2+) exchanger (NCX) activity was apparently increased. We conclude that TLR4 activation decreased Ito, which increased AP duration via a MyD88-independent, IRF3-dependent pathway. The longer action potential, associated with enhanced Ca(2+) efflux via NCX, could explain the presence of arrhythmias in the LPS group.

Endocytosis Of Tight Junctions Caveolin Nitrosylation Dependent Is Improved By Cocoa Via Opioid Receptor On Rpe Cells In Diabetic Conditions.

Retinal pigment epithelium cells, along with tight junction (TJ) proteins, constitute the outer blood retinal barrier (BRB). Contradictory findings suggest a role for the outer BRB in the pathogenesis of diabetic retinopathy (DR). The aim of this study was to investigate whether the mechanisms involved in these alterations are sensitive to nitrosative stress, and if cocoa or epicatechin (EC) protects from this damage under diabetic (DM) milieu conditions. Cells of a human RPE line (ARPE-19) were exposed to high-glucose (HG) conditions for 24 hours in the presence or absence of cocoa powder containing 0.5% or 60.5% polyphenol (low-polyphenol cocoa [LPC] and high-polyphenol cocoa [HPC], respectively). Exposure to HG decreased claudin-1 and occludin TJ expressions and increased extracellular matrix accumulation (ECM), whereas levels of TNF-α and inducible nitric oxide synthase (iNOS) were upregulated, accompanied by increased nitric oxide levels. This nitrosative stress resulted in S-nitrosylation of caveolin-1 (CAV-1), which in turn increased CAV-1 traffic and its interactions with claudin-1 and occludin. This cascade was inhibited by treatment with HPC or EC through δ-opioid receptor (DOR) binding and stimulation, thereby decreasing TNF-α-induced iNOS upregulation and CAV-1 endocytosis. The TJ functions were restored, leading to prevention of paracellular permeability, restoration of resistance of the ARPE-19 monolayer, and decreased ECM accumulation. The detrimental effects on TJs in ARPE-19 cells exposed to DM milieu occur through a CAV-1 S-nitrosylation-dependent endocytosis mechanism. High-polyphenol cocoa or EC exerts protective effects through DOR stimulation.

An Update On The Pharmacogenetics Of Treating Hypertension.

Hypertension is a leading cause of cardiovascular mortality, but only one third of patients achieve blood pressure goals despite antihypertensive therapy. Genetic polymorphisms may partially account for the interindividual variability and abnormal response to antihypertensive drugs. Candidate gene and genome-wide approaches have identified common genetic variants associated with response to antihypertensive drugs. However, there is no currently available pharmacogenetic test to guide hypertension treatment in clinical practice. In this review, we aimed to summarize the recent findings on pharmacogenetics of the most commonly used antihypertensive drugs in clinical practice, including diuretics, angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers, beta-blockers and calcium channel blockers. Notably, only a small percentage of the genetic variability on response to antihypertensive drugs has been explained, and the vast majority of the genetic variants associated with antihypertensives efficacy and toxicity remains to be identified. Despite some genetic variants with evidence of association with the variable response related to these most commonly used antihypertensive drug classes, further replication is needed to confirm these associations in different populations. Further studies on epigenetics and regulatory pathways involved in the responsiveness to antihypertensive drugs might provide a deeper understanding of the physiology of hypertension, which may favor the identification of new targets for hypertension treatment and genetic predictors of antihypertensive response.Journal of Human Hypertension advance online publication, 28 August 2014; doi:10.1038/jhh.2014.76.

Preserved Fertility In A Patient With Gynecomastia Associated With The P.pro695ser Mutation In The Androgen Receptor.

The androgen insensitivity syndrome (AIS) is described as a dysfunction of the androgen receptor (AR) in 46,XY individuals, which can be associated with mutations in the AR gene or can be due to unknown mechanisms. Different mutations in AIS generally cause variable phenotypes that range from a complete hormone resistance to a mild form usually associated with male infertility. The purpose of this study was to search for mutations in the AR gene in a fertile man with gynecomastia and to evaluate the influence of the mutation on the AR transactivation ability. Sequencing of the AR gene revealed the p.Pro695Ser mutation. It is located within the AR ligand-binding domain. Bioinformatics analysis indicated a deleterious role, which was verified after testing transactivation activity and N-/C-terminal (N/C) interaction by in vitro expression of a reporter gene and 2-hybrid assays. p.Pro695Ser showed low levels of both transactivation activity and N/C interaction at low dihydrotestosterone (DHT) conditions. As the ligand concentration increased, both transactivation activity and N/C interaction also increased and reached normal levels. Therefore, this study provides functional insights for the p.Pro695Ser mutation described here for the first time in a patient with mild AIS. The expression profile of p.Pro695Ser not only correlates to the patient's phenotype, but also suggests that a high-dose DHT therapy may overcome the functional deficit of the mutant AR.

Frequency Of The Allelic Variant C.1150t > C In Exon 10 Of The Fibroblast Growth Factor Receptor 3 (fgfr3) Gene Is Not Increased In Patients With Pathogenic Mutations And Related Chondrodysplasia Phenotypes.

Mutations in the FGFR3 gene cause the phenotypic spectrum of FGFR3 chondrodysplasias ranging from lethal forms to the milder phenotype seen in hypochondroplasia (Hch). The p.N540K mutation in the FGFR3 gene occurs in ∼70% of individuals with Hch, and nearly 30% of individuals with the Hch phenotype have no mutations in the FGFR3, which suggests genetic heterogeneity. The identification of a severe case of Hch associated with the typical mutation c.1620C > A and the occurrence of a c.1150T > C change that resulted in a p.F384L in exon 10, together with the suspicion that this second change could be a modulator of the phenotype, prompted us to investigate this hypothesis in a cohort of patients. An analysis of 48 patients with FGFR3 chondrodysplasia phenotypes and 330 healthy (control) individuals revealed no significant difference in the frequency of the C allele at the c.1150 position (p = 0.34). One patient carrying the combination `pathogenic mutation plus the allelic variant c.1150T > C' had a typical achondroplasia (Ach) phenotype. In addition, three other patients with atypical phenotypes showed no association with the allelic variant. Together, these results do not support the hypothesis of a modulatory role for the c.1150T > C change in the FGFR3 gene.