Bloqueadores do Receptor de Angiotensina Avaliados por Medida de Consultório e Residencial da Pressão Arterial. Estudo TeleMRPA / Angiotensin Receptor Blockers Evaluated by Office and Home Blood Pressure Measurements. TeleHBPM Study

Resumo Fundamento O tratamento adequado e a obtenção das metas na hipertensão arterial são importantes na redução dos desfechos cardiovasculares. Objetivos Descrever os bloqueadores do receptor de angiotensina (BRA) em monoterapia ou combinação dupla e a taxa de controle da hipertensão arterial. Métodos Estudo transversal que avaliou pacientes em uso de BRA entre 2017 e 2020. Foram excluídos aqueles em uso de três ou mais anti-hipertensivos. As variáveis analisadas foram: sexo, idade, índice de massa corporal, medidas válidas da medida residencial da pressão arterial (MRPA); pressão arterial sistólica (PAS) e diastólica (PAD) obtidas pela MRPA e de forma casual; variabilidade pressórica; classe dos anti-hipertensivos e dos BRAs. Foram utilizados testes de t pareado, qui-quadrado e Fisher, além de sobreposição dos intervalos de confiança de 95% com nível de significância de 5% (p < 0,05). Resultados Foram selecionados 17.013 pacientes; destes, 12.813 preencheram os critérios, dos quais 62,1% eram do sexo feminino. O número médio de medidas válidas foi de 23,3 (±2,0), com médias para a PAS de 126,8±15,8 mmHg e 133,5±20,1 mmHg (p < 0,001) e para a PAD de 79,1±9,7 mmHg e 83,6±11,9 mmHg (p < 0,001) pela MRPA e medida casual, respectivamente. Losartana foi o BRA mais utilizado e o que apresentou comportamentos mais elevados da pressão arterial. As combinações de BRA com diuréticos ou com antagonistas de canal de cálcio tiveram menores valores de pressão arterial. Conclusões Losartana foi utilizada em mais da metade dos pacientes, apesar de ser a menos eficiente na redução e no controle da pressão arterial.

Abstract Background Adequate treatment of arterial hypertension and achieving arterial hypertension goals in are important in reducing cardiovascular outcomes. Objectives To describe angiotensin receptor blockers in monotherapy or double combination therapy and the rate of arterial hypertension control. Methods This cross-sectional study evaluated patients who were using angiotensin receptor blockers between 2017 and 2020. Those using three or more antihypertensive drugs were excluded. The analyzed variables included sex, age, body mass index, valid home blood pressure monitoring (HBPM) measurements, casual and HBPM systolic and diastolic blood pressure measurements, blood pressure variability, and antihypertensive and angiotensin receptor blocker class. Paired t, chi-square, and Fisher's exact tests were used, as well as overlapping 95% confidence intervals and a significance level of 5% (p < 0.05). Results Of 17,013 patients, 12,813 met the inclusion criteria, 62.1% of whom were female. The mean number of valid measurements was 23.3 (SD, 2.0). The mean HBPM and casual measurements for systolic blood pressure were 126.8 (SD, 15.8) mmHg and 133.5 (SD, 20.1) mmHg (p <0.001), respectively, while those for diastolic blood pressure were 79.1 (SD, 9.7 mmHg) and 83.6 (SD, 11.9) mmHg (p <0.001), respectively. Losartan was the most common angiotensin receptor blocker and resulted in the highest blood pressure values. Combinations of angiotensin receptor blockers with diuretics or calcium channel antagonists resulted in lower blood pressure values. Conclusions More than half of the patients used losartan, although it was the least efficient drug for reducing and controlling blood pressure.

Correlation between angiotensin H level and clinical inflammatory indicators in patients with rheumatoid arthritis and therapeutic effect of angiotensin receptor blockers / 中国药理学通报

Aim To investigate the eorrelation between angiotensin II (Ang II ) level and clinical indicators in patients with rheumatoid arthritis ( HA) , and to determine the therapeutic effect of angiotensin receptor blockers ( ARBs).Methods Plasma samples and personal information were collected from HA patients admitted to our hospital from 2019 to 2021.The level of Ang II in plasma was determined by ELISA to elucidate the correlation between plasma Ang II level and the severity of HA.The pathological changes of synovi-al tissues and T eells subtype in different groups of HA patients were determined by pathological examination and flow cytometry.A rat model of collagen-induced arthritis (CIA) was established and the pathological examination was used to confirm that valsartan could alleviate the disease course in the CIA animal model.Results Compared with control group, the plasma level of Ang II in HA patients significantly increased.After therapy with oral ARBs plasma Ang H levels and anti - cyclic citrullinated peptide antibody ( CCP) titre were significantly lower than those untreated HA patients.The level of Ang II in plasma was positively correlated with CCP and the number of monocytes, but negatively with number of RBC and hemoglobin content.Staining of synovial tissue with HE and Masson found that patients with HA had significant synovial proliferation, pannus formation , and numerous inflammatory cell infiltrates compared with control patients.Immunohistochemical results showed significant infiltration of CD4 4 T cells in synovial tissues of HA patients.Western blot and immunofluorescence analysis showed that the expression of angiotensin type 1 receptor ( ATI R ) was significantly up-regulated in CD4 + T cells and synovial tissues of HA patients.The results of animal experiments showed that valsartan harl therapeutic effect on CIA rats and could delay the disease process of CIA.Conclusions Plasma Ang II level is positively correlated with CCP level and HA severity.ARBs can down-regualte CCP level and delay disease progression in HA patients.Animal experiments showed that valsartan blocks the combination of Ang H and ATI R and has therapeutic effect on a CIA rat model.This study provides the theoretical and experimental basis for ARBs to become the preferred antihypertensive drugs for HA patients with hypertension.

Effects of different doses of dexamethasone on angiotensin II, its receptors and NO levels in septic kidney injury rats / 中国临床药理学与治疗学

AIM: To investigate the changes of angiotensin II, its receptors and nitric oxide (NO) expression in rats with acute kidney injury (AKI) induced by endotoxin (LPS) and to assess the efficacy of different doses of dexamethasone (DXM). METHODS: Wistar rats were randomly divided into five groups as follows: control group (NC), LPS group, and DXM treatment groups of different doses of DXM (0.5, 1.0 and 5.0 mg/kg). The AKI group was injected with LPS through the lateral tail vein, and the intervention group was given different doses of DXM after LPS injection. Tissue samples were collected at 2, 6, 12 and 24 h after treatment. Serum creatinine and urea nitrogen levels were determined by automatic biochemical analyzer. H&E staining was used to observe renal histopathology. Serum TNF-α and MIP-1α levels were determined by ELISA. The expression of the angiotensin receptor 1 (AT1R) and angiotensin receptor 2 (AT2R) proteins were detected by Western blot and immunohistochemistry. Nitrate reductase was used to detect NO changes in the serum and renal tissues. RESULTS: The serum levels of serum TNF-α, MIP-1α, creatinine, and urea nitrogen were significantly increased in the LPS group compared with the control group (P<0.05). A similar trend was also observed in the levels of plasma and renal tissue AngII, renal tissue AT2R, serum and renal tissue NO (P<0.05). The expression of AT1R in renal tissue was significantly decreased in the LPS group compared with the control group (P<0.05). Pathological analysis showed that glomerular neutrophil infiltration and renal tubular epithelial cells swelling, vacuolar degeneration and necrosis in the LPS group. Prolongation LPS treatment resulted in more significant kidney damage. The serum levels of TNF-α, MIP-1α, creatinine, and urea nitrogen were significantly decreased in the DXM group compared with the LPS group (P<0.05). A similar trend was also observed in the levels of plasma and renal tissue AngII, renal tissue AT2R, serum and renal tissue NO in the DXM group (P<0.05). The expression of AT1R in renal tissue was significantly increased (P<0.05) in the DXM group compared with the LPS group, indicating the alleviation of kidney injury. Amongst these biomarkers, the levels of serum TNF-α, MIP-1α, plasma AngII showed the most significant decrease in the high dose DMX group (P<0.05). The levels of serum creatinine, urea nitrogen, kidney NO showed more significant decreases in the low and medium dose DMX groups (P<0.05). The levels of kidney AngII to dose and AT1R showed the most significant decrease in medium and high dose DXM groups (P<0.05). The levels of kidney AT2R and serum NO were not significantly different between the DXM treatment groups. CONCLUSION: LPS can induce AKI in rats that can be mitigated by DXM. The mechanism of DXM in protection against AKI may be related to the down-regulation of inflammatory factors such as AngII, AT2R, and NO, and the up-regulation of AT1R expression. Different doses of dexamethasone have different intervention effects for different effector molecules.

O uso de inibidores do Sistema Renina-Angiotensina pode aumentar a suscetibilidade à infecção pelo SARS-CoV-2 (COVID-19)? / Can the use of Renin-Angiotensin System inhibitors increase the susceptibility to SARSCoV-2 infection (COVID-19)?

Diante do contexto pandêmico da COVID-19, esforços têm sido direcionados ao desenvolvimento de medidas terapêuticas seguras e eficazes no combate à doença. Entretanto, divergências entre as condutas adotadas nesses pacientes tem sido frequentes. Em especial, fármacos inibidores do Sistema Renina-Angiotensina, como os Inibidores da Enzima Conversora de Angiotensina e Bloqueadores do Receptor da Angiotensina, são foco de grande discussão. Diversos autores questionam uma possível relação de risco aumentado entre o uso de tais medicações e o desenvolvimento de formas mais graves da doença, ao correlacionar a regulação positiva da Enzima Conversora de Angiotensina 2 induzida por esses fármacos com o fato do SARS-CoV-2 usar essa enzima como receptor celular. Enquanto isso, outros autores defendem que essa modulação atue como fator protetor à gravidade da infecção, levando em consideração a promoção de efeitos vasodepressores, anti-fibróticos e anti-inflamatórios. Dada a alta prevalência do uso desses anti-hipertensivos, a presente revisão analisa o funcionamento do Sistema Renina-Angiotensina; aspectos moleculares do novo coronavírus; e a inibição da Angiotensina 2 no contexto dessa infecção, para discutir qual conduta seria mais adequada no manejo da hipertensão arterial e doenças cardiovasculares, dada a pandemia da COVID-19.

In the face of the pandemic context of the COVID-19, efforts have been directed to the development of safe and effective therapeutic actions in combating the disease. However, divergences between management of these patients have been frequent. Especially, Renin-Angiotensin System inhibitors, as Angiotensin-Converting Enzyme Inhibitors and Angiotensin Receptor Blockers, are the focus of great discussion. Several authors question a possible increased risk relation between the use of that medication and the development of the most severe disease form, when correlating AngiotensinConverting Enzyme 2 upregulation induced by those drugs with the fact that SARS-CoV-2 uses this enzyme as its cellular receptor. Meanwhile, other authors defend that the referred modulation acts as a protective factor to infection severity, considering the induction of vasodepressor, antifibrotic and anti-inflammatory effects. Given the high prevalence of the use of those antihypertensive drugs, the present review analyses the Renin-Angiotensin System functionning; molecular aspects of the novel coronavirus; and the Angiotensin 2 inhibition in the context of this infection, in order to discuss which conduct would be more appropriate in the management of arterial hypertension and cardiovascular diseases, given the COVID-19 pandemic.

Parkinsonismo inducido por telmisartán: Reporte de caso / Induced parkinsonism for telmisartan: case report

RESUMEN INTRODUCCIÓN: El parkinsonismo es un síndrome clínico, caracterizado por temblor, rigidez y bradicinesia, debido a la alteración en el circuito dopaminérgico ganglio-basal, específicamente a nivel nigroestriatal. A continuación se presenta un caso de parkinsonismo inducido por telmisartán. PRESENTACIÓN DE CASO: Hombre de 78 años, con antecedentes de enfermedad de Parkinson de dos años de evolución, controlada con levodopa, pramipexol ER y amantadina, ingresa al servicio de urgencias por empeoramiento del parkinsonismo en las dos semanas previas a la consulta. Tenía antecedente de infarto cerebral en el territorio de la arteria cerebral posterior izquierda, hipertensión arterial crónica y diabetes mellitus tipo 2. Al examen neurológico presentaba bradicinesia y rigidez severa en las cuatro extremidades, con limitación significativa de la marcha, asociado a mioclonías. Se descartaron alteraciones infecciosas, metabólicas y lesiones agudas en la tomografía cerebral, por lo que se suspendió el telmisartán, posteriormente a lo cual los síntomas mejoraron. DISCUSIÓN: El parkinsonismo secundario a fármacos constituye la primera causa de este síndrome, en varios modelos farmacológicos se describe la acción que estos ejercen sobre los receptores dopaminérgicos. Así, el parkinsonismo inducido por telmisartán se considera desencadenado por disrupción dopaminérgica secundaria al antagonismo de los receptores de la angiotensina II a nivel de la sustancia gris periacueductal.

SUMMARY INTRODUCTION: Parkinsonism is a clinical syndrome characterized by tremor, rigidity, and bradykinesia due to alteration in the basal-ganglia dopaminergic circuit, specifically at the nigrostriatal level. The following is a case of parkinsonism induced by telmisartan. CASE PRESENTATION: A 78-year-old man with a 2-year history of Parkinson's disease of controlled evolution with levodopa, pramipexole ER, amantadine was admitted to the emergency department due to worsening of parkinsonism in the two weeks prior to consultation. He had a history of cerebral infarction in the territory of the left posterior cerebral artery, chronic arterial hypertension, and type 2 diabetes mellitus. On neurological examination, he presented bradykinesia and severe stiffness in all four limbs with significant limitation of gait, associated with myoclonus. Infectious and metabolic alterations and acute lesions were ruled out in the brain tomography, so telmisartan was suspended, after which the symptoms improved. DISCUSSION: Drug-induced parkinsonism is the first cause of this syndrome, and the action they exert on dopaminergic receptors has been described in several pharmacological models. Telmisartan-induced parkinsonism is considered triggered by dopaminergic disruption secondary to angiotensin II receptor antagonism at the periaqueductal gray substance level.

Bloqueio de Receptores AT1 Melhora o Desempenho Funcional Miocárdico na Obesidade / AT1Receptor Blockade Improves Myocardial Functional Performance in Obesity

Resumo Fundamento A obesidade tem sido associada com ativação crônica do sistema renina-angiotensina-aldosterona e importantes alterações no desempenho cardíaco. Objetivo Avaliar a influência do bloqueio de receptores de angiotensina-II do tipo 1 (AT1) sobre a morfologia e desempenho cardíaco de ratos obesos por dieta Métodos Ratos Wistar (n=48) foram submetidos a dieta controle (2,9 kcal/g) ou hiperlipídica (3,6 kcal/g) durante 20 semanas. Após a 16ª semana, foram distribuídos em quatro grupos: Controle (CO), Obeso (OB), Controle Losartan (CL) e Obeso Losartan (OL). CL e OL receberam losartan (30 mg/kg/dia) na água durante quatro semanas. Posteriormente, foram analisadas composição corporal, pressão arterial sistólica (PAS) e ecocardiograma. A função de músculos papilares foi avaliada em situação basal com concentração de cálcio ([Ca2+]o) de 2,50 mM e após manobras inotrópicas: potencial pós-pausa (PPP), elevação da [Ca2+]o e durante estimulação beta-adrenérgica com isoproterenol. A análise dos resultados foi feita por meio de Two-Way ANOVA e teste de comparações apropriado. O nível de significância considerado foi de 5%. Resultados Embora a alteração da PAS não tenha se mantido ao final do experimento, a obesidade se associou com hipertrofia cardíaca e maior velocidade de encurtamento da parede posterior do ventrículo esquerdo.No estudo de músculos papilares em condição basal, CL mostrou menor velocidade máxima de variação negativa da tensão desenvolvida (-dT/dt) do que CO. O PPP de 60s promoveu menor -dT/dt e pico de tensão desenvolvida (TD) em OB e CL, comparados ao CO, e maior variação relativa de TD e velocidade máxima de variação positiva (+dT/dt) no OL em relação a CL e OB. Sob 1,5, 2,0 e 2,5mM de [Ca2+]o, o grupo OL exibiu maior -dT/dt do que CL. Conclusão Losartan melhora a função miocárdica de ratos com obesidade induzida por dieta. (Arq Bras Cardiol. 2020; 115(1):17-28)

Abstract Background Obesity has been associated with chronic activation of the renin-angiotensin-aldosterone system and with significant changes in cardiac performance. Objective To assess the impact of a blockade of angiotensin-II receptor type 1 (AT1receptor) on morphology and on myocardial functional performance in rats with high-fat diet- induced obesity. Methods Wistar rats (n=48) were submitted to control (2.9 kcal/g) or high-fat (3.6 kcal/g) diet for 20 weeks. After the 16thweek they were divided into four groups: Control (CO), Obese (OB), Control Losartan (CL) and Obese Losartan (OL). CL and OL received losartan (30 mg/kg/day) in drinking water for four weeks. Subsequently, body composition, systolic blood pressure (SBP) and echocardiographic variables were analyzed. Papillary muscle function was assessed at baseline with 2.50 mM calcium concentration ([Ca2+]o) and after inotropic maneuvers: post-pause potentiation (PPP), [Ca2+]oelevation, and during beta-adrenergic stimulation with isoproterenol. Analysis of the results was performed by the Two-Way ANOVA and by the appropriate comparison test. The level of significance was set at 5%. Results Although SBP change had been not maintained at the end of the experiment, obesity was associated with cardiac hypertrophy and with increased left ventricle posterior wall shortening velocity. In the study of papillary muscles in basal condition, CL showed lower developed tension maximum negative variation velocity (-dT/dt) than CO. The 60s PPP promoted lower -dT/dt and maximum developed tension (DT) in OB and CL compared with CO, and higher relative DT variation and maximum positive variation velocity (+dT/dt) in OL compared with CL and OB. Under 1.5, 2.0, and 2.5mM [Ca2+]o, the OL group showed higher -dT/dt than CL. Conclusion Losartan improves myocardial function in high-fat diet-induced obesity. (Arq Bras Cardiol. 2020;115(1):17-28)

Planejamento e desenvolvimento de ligantes não peptídicos com atividade agonista enviesada no receptor de angiotensina II tipo 1 empregando-se técnicas de modelagem molecular e ensaios in vitro / Drug design of non-peptidic biased agonists for angiotensin II type 1 receptor using molecular modeling techniques and in vitro tests

A insuficiência cardíaca (IC) é uma síndrome de elevada morbimortalidade, correspondendo a um grave problema de saúde pública. Uma das abordagens terapêuticas para IC consiste no uso de antagonistas do receptor de angiotensina II do tipo 1 (AT1R), conhecidos como sartanas. Estudos apontam que uma nova classe de compostos, os agonistas enviesados, é capaz de induzir a sinalização da via da ß-arrestina sem ativação da via da proteína G. Essa seletividade funcional é particularmente interessante, pois a via dependente da proteína G é responsável pelo aumento da pressão arterial, morte celular e fibrose tecidual, levando a hipertrofia cardíaca e progressão da IC. No entanto, a via da ß-arrestina está associada com renovação celular e aumento do inotropismo. Além disso, estudos in vivo sugerem que agonistas enviesados poderiam corresponder a uma terapia superior à dos antagonistas convencionais, que bloqueiam ambas as vias. Apesar do potencial terapêutico, esses compostos possuem estrutura peptídica e, por isso, tem sua administração restrita à via intravenosa. A resolução da estrutura cristalográfica do AT1R permitiu estudos de modelagem molecular mais acurados. Tendo isso em mente, nesse trabalho foram propostos agonistas enviesados de natureza não peptídica para o AT1R por meio de técnicas de modelagem molecular e validação das hipóteses levantadas por ensaios in vitro. Foram realizados estudos de dinâmica molecular com o AT1R (PDB ID: 4YAY) em uma bicamada lipídica e ensaios de ancoramento molecular da angiotensina II (AngII) e do ligante enviesado TRV027. As poses de ancoramento molecular selecionadas foram utilizadas em dinâmicas de complexo, que revelaram diferenças entre os sistemas apo (sem nenhum ligante) e holo (com o ligante no sitio de ligação). Nossos resultados sugerem que o TRV027 induz um padrão exclusivo de ligações de hidrogênio e de estrutura secundária, enquanto que a AngII afeta os resíduos do bolso hidrofóbico do sitio de ligação, principalmente a conformação do Trp2536.48. Com base nas simulações, três farmacóforos foram criados e utilizados de maneira complementar em triagens virtuais na base de dados ZINC15, resultando na seleção de cinco compostos. Um desses compostos apresentou afinidade pelo receptor AT1R e, ainda que estudos complementares de ativação de vias especificas sejam necessários para que o composto possa ser classificado como agonista enviesado, já se constitui em molécula potencialmente promissora. Além disso, esses estudos permitiram a proposição de estruturas inéditas que podem vir a ser hits no processo de desenvolvimento de agonistas enviesados para AT1R. Portanto, como continuidade desse trabalho, essas moléculas serão sintetizadas e investigadas quanto à possível interação com o receptor.

Heart Failure (HF) is a common syndrome with high morbimortality, being considered a serious public health problem. One of the therapeutic approaches for HF consists in the use of the sartan class, which are angiotensin II type 1 receptor (AT1R) antagonists. Recent studies have shown that a new class of compounds, known as biased agonists, is able to induce signaling via ß-arrestin without G-protein activation. This functional selectivity is particularly interesting since G-protein dependent signaling is responsible for cell death and cardiac tissue fibrosis, which leads to cardiac muscle hypertophy and HF progression. On the other hand, ß-arrestin signaling is associated with cellular renewal and increased inotropism. In vivo studies suggests that biased agonists could correspond to a superior therapy over conventional angiotensin II type 1 receptor antagonists, which blocks cell signaling as a whole, however their peptidic structure restricts their use to intravenous administration. Moreover, the AT1R crystal structure determination holds great promise for more accurate molecular modeling studies. With that being said, the aim of this work was to plan and develop new non-peptidic biased agonists for ATR1 employing molecular modeling techniques and in vitro tests for hypothesis validation. Molecular dynamics (MD) simulations of the refined AT1R crystal (PDB ID: 4YAY) embedded in a lipid bilayer and molecular docking studies with angiotensin II (AngII) and TRV027 (biased agonist) were conducted. Selected docking poses from both ligands underwent complex MD simulations revealing differences between apo (ligand free) and holo (ligand in the binding site) systems. Our results suggest that TRV027 induces an exclusive hydrogen bond and secondary structure pattern, while AngII affects the hydrophobic pocket conformation, mainly Trp253. Based on the simulations, three pharmacophore models were created and used in virtual screenings in the ZINC15 database, resulting in the selection of five compounds that were tested in vitro. One of the compounds displayed affinity for AT1R and is a promising molecule. Nonetheless, it needs further pathway activation characterization in order to be a classified as a biased agonist. Furthermore, these results have contributed significantly for the proposition of new structures that could be hits with biased agonist activity for AT1R. Thus, for future works, we point out the necessity for synthesis and characterization of this new compounds

Angiotensin II Type 1 Receptor Blocker, Fimasartan, Reduces Vascular Smooth Muscle Cell Senescence by Inhibiting the CYR61 Signaling Pathway

BACKGROUND AND OBJECTIVES: Angiotensin II (Ang II) has been suggested to accelerate vascular senescence, however the molecular mechanism(s) remain unknown. METHODS: We cultured human coronary artery smooth muscle cells (hCSMCs) and treated Ang II and/or fimasartan. Or we transfected adenoviral vectors expressing CYR61 (Ad-CYR61) or antisense CYR61 (Ad-As-CYR61). Cellular senescence was evaluated senescence-associated β-galactosidase (SA-β-gal) assay. The molecular mechanisms were investigated real-time PCR and western blots. RESULTS: SA-β-gal-positive cells significantly increased in Ang II-treated hCSMCs (5.77±1.43-fold compared with the control). The effect of Ang II was significantly attenuated by pretreatment with the Ang II type 1 receptor blocker, fimasartan (2.00±0.92-fold). The expression of both p53 and p16 senescence regulators was significantly increased by Ang II (p53: 1.39±0.17, p16: 1.19±0.10-fold vs. the control), and inhibited by fimasartan. Cysteine-rich angiogenic protein 61 (CYR61) was rapidly induced by Ang II. Compared with the control, Ad-CYR61-transfected hCSMCs showed significantly increased SA-β-gal-positive cells (3.47±0.65-fold). Upon transfecting Ad-AS-CYR61, Ang II-induced senescence (3.74±0.23-fold) was significantly decreased (1.77±0.60-fold). p53 expression by Ang II was significantly attenuated by Ad-AS-CYR61, whereas p16 expression was not regulated. Ang II activated ERK1/2 and p38 MAPK, which was significantly blocked by fimasartan. ERK and p38 inhibition both regulated Ang II-induced CYR61 expression. However, p53 expression was only regulated by ERK1/2, whereas p16 expression was only attenuated by p38 MAPK. CONCLUSIONS: Ang II induced vascular senescence by the ERK/p38 MAPK–CYR61 pathway and ARB, fimasartan, protected against Ang II-induced vascular senescence.

Clinical Impact of Pre-transplant Antibodies Against Angiotensin II Type I Receptor and Major Histocompatibility Complex Class I-Related Chain A in Kidney Transplant Patients

BACKGROUND: Evidence of antibody-mediated injury in the absence of donor-specific HLA antibodies (HLA-DSA) has recently emerged, suggesting a role of antibodies in targeting non-HLA antigens expressed on renal allograft tissue. However, the clinical significance of pre-transplant non-HLA antibodies remains unclear. We compared the histological and clinical impact of pre-transplant HLA-DSA and non-HLA antibodies, especially angiotensin II type I receptor (anti-AT1R) and MHC class I-related chain A (anti-MICA), in kidney transplant patients. METHODS: Pre-transplant HLA-DSA, anti-AT1R, and anti-MICA were retrospectively examined in 359 kidney transplant patients to determine the effect of each antibody on allograft survival and clinical characteristics. RESULTS: Pre-transplant HLA-DSA, anti-AT1R, and anti-MICA were detected in 37 (10.3%), 174 (48.5%), and 50 patients (13.9%), respectively. Post-transplant antibody-mediated rejection was associated with a pre-transplant HLA-DSA (+) status only. The development of microvascular inflammation (MVI) was associated with pre-transplant HLA-DSA (P=0.001) and anti-AT1R (P=0.036). Anti-AT1R (+) patients had significantly lower allograft survival compared with anti-AT1R (−) patients (P=0.042). Only pre-transplant anti-AT1R positivity was an independent risk factor for allograft failure (hazard ratio 4.824, confidence interval 1.017–24.888; P=0.038). MVI was the most common histological feature of allograft failure in patients with pre-transplant anti-AT1R. CONCLUSIONS: Pre-transplant anti-AT1R is an important risk factor for allograft failure, which may be mediated by MVI induction in the allograft tissue.

Safety and efficacy of fimasartan in Mexican patients with grade 1-2 essential hypertension / Seguridad y eficacia de fimasartán en pacientes mexicanos con hipertensión esencial de grados 1-2

Abstract: Objective: To evaluate efficacy and safety of 60 mg and 120 mg Fimasartan (FMS) alone or combined with 12.5 mg hydrochlorothiazide (HCTZ) in a Mexican population. Methods: A six month, treat-to-target, open study was conducted on subjects with grade 1-2 hypertension. The subjects were initially treated with 60 mg FMS once daily. In week 8, those with Diastolic Blood Pressure (DBP) <90 mmHg continued on the same FMS dose during the rest of the study, while those with DBP ≥90 mmHg were randomised to either 120 mg FMS or 60 mg FMS + 12.5 mg HCTZ once daily. In week 12, randomised subjects with DBP ≥90 mmHg received 120 mg FMS + 12.5 mg HCTZ, while those achieving target continued with their assigned treatment until the end of the study. Results: FMS 60 mg (n = 272) decreased both DBP and Systolic Blood Pressure (SBP) by 11.3 ± 8.9 (p<.0001) and 16.0 ± 14.1 (p<.0001) mmHg, respectively, with 75.4% of subjects reaching the treatment target. Subjects assigned to FMS 120 mg, FMS 60 mg + HCTZ 12.5 mg, or FMS 120 mg + HCTZ 12.5 mg once daily, showed significant reductions in DBP and SBP with their assigned treatment. At the end of the study, 237/272 subjects (87.1%) achieved a DBP < 90 mmHg and an SBP<140 mmHg. The most frequently reported adverse reactions included headache (3.7%), dry mouth (1.1%), transient liver enzyme increase (1.1%), and dizziness (0.7%). Conclusion: Fimasartan is safe and effective in Mexican subjects with grade 1-2 essential hypertension.

Resumen: Objetivo: Evaluar la eficacia y la seguridad de 60 y 120 mg de fimasartán (FMS) solo o combinado con 12.5 mg de hidroclorotiazida (HCTZ) en población mexicana. Métodos: Estudio abierto, de 24 semanas, con tratamiento escalado hasta el objetivo terapéutico en sujetos hipertensos grados 1-2. Tratamiento inicial: FMS 60 mg una vez al día; en la semana 8, los sujetos con presión arterial diastólica (PAD) <90 mmHg mantuvieron su tratamiento inicial durante el estudio, mientras que los sujetos con PAD ≥90 mmHg fueron aleatorizados a 120 mg de FMS o a 60 mg de FMS + 12.5 mg de HCTZ. En la semana 12, los sujetos aleatorizados con PAD ≥90 mmHg recibieron 120 mg de FMS + 12.5 mg de HCTZ; quienes alcanzaron el objetivo terapéutico mantuvieron su tratamiento asignado hasta finalizar el estudio. Resultados: FMS 60 mg (n = 272) disminuyó la PAD y la presión arterial sistólica (PAS) en 11.3 ± 8.9 (p < 0.0001) y 16.0 ± 14.1 (p < 0.0001) mmHg, respectivamente, con logro del objetivo de tratamiento en el 75.4% de los sujetos. Los sujetos asignados a 120 mg de FMS, a 60 mg de FMS + 12.5 mg de HCTZ 12.5 y a 120 mg de FMS + 12.5 mg de HCTZ mostraron reducciones significativas de PAD y PAS; al final del estudio, 237/272 sujetos (87.1%) lograron PAD <90 y PAS <140 mmHg. Las reacciones adversas más frecuentemente reportadas fueron: cefalea (3.7%), boca seca (1.1%), incremento de enzimas hepáticas (1.1%) y mareo (0.7%). Conclusión: FMS es seguro y eficaz en sujetos mexicanos con hipertensión esencial de grados 1-2.

Potential radioprotective effect of AT1 receptor antagonists against morphological and ultrastructural changes in the testes induced by ionizing radiation / Potencial efecto radioprotector de antagonistas del receptor AT1 contra los daños morfológicos y ultraestructurales en los testículos inducido por la radiación ionizante

Radiotherapy is a source of human exposure to ionizing radiation. This pure energy causes deleterious effects on tissues, which result from oxidative stress, a phenomenon in which there is the participation of the Renin-Angiotensin System (RAS). The male genital organs are extremely radiosensitive and the action of radiation in the testes can significantly affect spermatogenesis. In search of potential radioprotective for male genital system, this study investigated whether the AT1 receptor antagonists minimize radiation-induced damage to reproductive tissues, by decreasing oxidative stress. Male Wistar rats were divided into six groups: 0 Gray (Gy) (control), 5 Gy (single dose in the scrotal area), telmisartan, losartan, 5Gy+telmisartan and 5Gy+losartan. The treatment started the day after irradiation with losartan 34 mg/kg (two times/day) and telmisartan 12 mg/kg (one time/day) during 60 days. For ultrastructural analysis, the testis fragments were fixed in 2 % glutaraldehyde and 4 % paraformaldehyde in 0.1 M phosphate buffer, pH 7.3. The material was postfixed for 2 h in 1 % osmium tetroxide. For collagen evaluation, the sections were stained with Picrosirius-red method. Serum testosterone was determined. The date showed the deleterious effects of gamma radiation on testicular ultrastructure. Rich accumulation of collagen fibers in the interstitium was observed in the irradiated groups, especially the irradiated and nontreated testes. No significant difference was detected in serum testosterone concentration among the studied experimental groups. Treatments with telmisartan and losartan influenced the onset of attenuation on ultrastructural damages arising from ionizing radiation. Although the data strongly suggest that AT1 receptor antagonists may promote radioprotection to the testes, further studies with a longer duration of treatment are required for these potentially positive effects to be maximized and, therefore, to better characterize radioprotection to reproductive parameters.

El tratamiento radioterápico es una fuente de exposición del ser humano a la radiación ionizante. Esta energía pura causa efectos deletéreos en los tejidos, debido al estrés oxidativo, fenómeno donde hay participación del Sistema Renina-Angiotensina. Los órganos genitales masculinos son extremadamente radiosensibles y la acción de la radiación en los testículos puede afectar significativamente la espermatogénesis. En la búsqueda de potenciales radioprotectores, este estudio ha investigado fármacos antagonistas del receptor AT1 que minimizan los daños radioinduzidos en los tejidos reproductivos, por medio de la disminución del estrés oxidativo. Ratones Wistar machos fueron distribuidos en seis grupos: grupo 0 Gray (Gy) (control), grupo 5 Gy (dosis única en el área escrotal), grupo telmisartán, grupo losartán, grupo 5Gy+telmisartán y grupo 5Gy+losartán. El tratamiento empezó en el día siguiente a la irradiación con losartán 34 mg/kg (2x/día) y telmisartán 12 mg/kg (1x/día), durante 60 días. Para el análisis ultraestructural, los testículos se fijaron en glutaraldehido (2 %) y paraformaldehido (4 %) con tampón de fosfato 0,1 M, pH 7,3. El material fue post-fijado en tetróxido de osmio (1 %). Para evaluar el colágeno fue utilizado el método Picrosirius Red. Fue determinada la concentración sérica de testosterona. Los datos mostraron los efectos deletéreos de los rayos gamma sobre la ultraestructura testicular. Fue observada una rica deposición de colágeno en el intersticio en los grupos irradiados, especialmente en el irradiado y no tratado. Entre los grupos, no se detectó ninguna diferencia significativa en la concentración sérica de testosterona. Los tratamientos con telmisartán y losartán influenciaron el comienzo de la atenuación de los cambios en la ultraestructura testicular de la radiación. A pesar de que los datos sugieren que los antagonistas del receptor AT1 pueden promover radioprotección a los testículos, estudios complementarios con una duración de tratamiento más extendida son necesarios para que los efectos potencialmente positivos sean maximizados y, por supuesto, puedan mejorar la caracterizacion de la radioprotección a los parámetros reproductivos.

Role of AT1 R-CaN signaling pathway in regulation of Nav1.5 protein ex-pression in hypertrophic ventricular myocytes from neonatal rats / 中国病理生理杂志

AIM:To investigate the effect of angiotensin II type 1 receptor (AT1R)-calcineurin (CaN) signa-ling pathway on the expression of sodium current channel Nav 1.5 at mRNA and protein levels in the hypertrophic ventricu-lar myocytes from neonatal rats .METHODS:The ventricular myocytes were isolated from the ventricles of 1-day-old neo-natal Sprague-Dawley rats and were divided into 4 groups according to different drug intervention as control group , pheny-lephrine (PE) group, losartan (Los)+PE group and cyclosporin A (CsA)+PE group.The method of RNA interference mediated by adenovirus carrying short hairpin RNA ( shRNA) was used to knock down the gene which encodes the beta subtype of CaN A subunit (CnAβ) and the cells were divided into 4 groups as Ad-Null group, Ad-Null+PE group, Ad-CnAβshRNA1 group and Ad-CnAβshRNA1+PE group.The mRNA expression of brain natriuretic peptide ( BNP) ,β-my-osin heavy chain (β-MHC) and Nav1.5 was detected by RT-qPCR.The protein levels of CnAβand Nav1.5 in the whole-cell extracts were determined by Western blot analysis .RESULTS:Treatment of the neonatal rat ventricular myocytes with PE for 24 h increased the protein-to-DNA ratio and the mRNA expression of BNP and β-MHC.The size of the cell surface was also increased after PE treatment .Treatment of the cells with PE increased the protein expression of CnAβ, and re-duced the protein expression of Nav 1.5.Both Los and CsA prevented those effects of PE .The mRNA expression of Nav1.5 was reduced by PE , and no significant difference of Nav 1.5 mRNA expression among PE group , Los+PE group and CsA+PE group was observed .Silencing of CnAβin the neonatal rat ventricular myocytes using Ad-CnAβshRNA1 inhibited the ability of PE to increase the mRNA expression of BNP , and diminished the ability of PE to reduce the protein expression of Nav1.5.CONCLUSION:AT1 R-CaN signaling pathway participates in regulating protein expression of Nav 1.5 in the hy-pertrophic ventricular myocytes from neonatal rats .

24-Hour blood pressure response to lower dose (30 mg) fimasartan in Korean patients with mild to moderate essential hypertension

BACKGROUND/AIMS: Fimasartan is an angiotensin type 1 receptor blocker (ARB) which has comparable efficacy and tolerability with other ARBs. The aim of this study was to evaluate 24-hour blood pressure (BP) lowering efficacy and the tolerability of the low dose fimasartan compared with valsartan in patients with mild to moderate hypertension. METHODS: This study was a phase II, prospective, multicenter, randomized, double-blind, parallel-grouped trial. A total of 75 hypertensive patients, whose mean ambulatory BP monitoring values were ≥ 135/85 mmHg, were randomized to either fimasartan 30 mg or valsartan 80 mg daily. The primary efficacy endpoint was the change in the mean 24-hour systolic BP (SBP) values from the baseline and at the week 8. Secondary endpoints included the change in the mean 24-hour diastolic BP values, the daytime and the nighttime mean BP values at week 8, the trough-to-peak (T/P) ratio and the smoothness index. RESULTS: At week 8, the mean 24-hour SBP values significantly decreased in both groups; –10.5 ± 11.9 mmHg (p < 0.0001) in the fimasartan group and –5.5 ± 11.6 mmHg (p = 0.0307) in the valsartan group. The difference between two groups was 4.3 ± 2.9 mmHg but there was no statistical significance (p = 0.1392). The global T/P ratio in the fimasartan 30 mg groups were 0.48 and 0.40 in the valsartan 80 mg group, respectively (p = 0.3411). The most frequent adverse events (AEs) were acute pharyngitis and there were no cases of severe AEs. CONCLUSIONS: In mild-to-moderate hypertensive patients, low dose (30 mg) fimasartan showed comparable 24-hour BP lowering efficacy compared with valsartan (80 mg). There was no difference in tolerability between two groups.

Effect of electroacupuncture stimulation on expression of angiotensinogen, angiotensin II type 1 receptor, endothelin-1, and endothelin a receptor mRNA in spontaneously hypertensive rat aorta / 中国结合医学杂志

<p><b>OBJECTIVE</b>To observe the effect of electroacupuncture (EA) stimulation on the expressions of angiotensinogen (AGT), angiotensin II type 1 receptor (AT1R), endothelin-1 (ET1), and endothelin A receptor (ETAR) mRNA in spontaneously hypertensive rat (SHR) aorta.</p><p><b>METHODS</b>Eighteen male SHRs were randomly divided into three groups, an SHR group, an SHR Baihui (DU 20) and Zusanli (ST 36) acupoint (SHR-AP) group, and an SHR non-acupoint (SHR-NAP) group, with 6 rats in each group. Six Wistar rats were used as a control. Rats in the SHR-AP group were stimulated by DU 20 and ST 36 acupoints, both of which were connected with EA. EA was handled one time every Monday, Wednesday and Friday, for total 24 times (8 weeks). SHRNAP rats were acupointed at a 15°angle flat into 0.5 cm to two points, which were 1 and 2 cm from rail tip separately. EA parameters were the same as the SHR-AP rats. SHR control rats and Wistar rats were fixed without EA. Real-time quantitative polymerase chain reaction (PCR) was used to measure AGT, AT1R, ET1, and ETAR mRNA expression in rat aorta.</p><p><b>RESULTS</b>EA stimulation significantly reduced rat aorta vascular AGT, ET1, ETAR and AT1R mRNA expressions in the SHR-AP and SHR-NAP groups (P <0.01). Among these four genes, AT1R mRNA expression was significantly lower in the SHR-AP than in the SHR-NAP group (P <0.01).</p><p><b>CONCLUSION</b>EA could reduce the AT1R mRNA expression in SHR-AP rat aorta, indicating a potential mechanism for the hypotensive effects of EA.</p>

Angiotensin II type 1 receptor blockers as a first choice in patients with acute myocardial infarction

BACKGROUND/AIMS: Angiotensin II type 1 receptor blockers (ARBs) have not been adequately evaluated in patients without left ventricular (LV) dysfunction or heart failure after acute myocardial infarction (AMI). METHODS: Between November 2005 and January 2008, 6,781 patients who were not receiving angiotensin-converting enzyme inhibitors (ACEIs) or ARBs were selected from the Korean AMI Registry. The primary endpoints were 12-month major adverse cardiac events (MACEs) including death and recurrent AMI. RESULTS: Seventy percent of the patients were Killip class 1 and had a LV ejection fraction > or = 40%. The prescription rate of ARBs was 12.2%. For each patient, a propensity score, indicating the likelihood of using ARBs during hospitalization or at discharge, was calculated using a non-parsimonious multivariable logistic regression model, and was used to match the patients 1:4, yielding 715 ARB users versus 2,860 ACEI users. The effect of ARBs on in-hospital mortality and 12-month MACE occurrence was assessed using matched logistic and Cox regression models. Compared with ACEIs, ARBs significantly reduced in-hospital mortality(1.3% vs. 3.3%; hazard ratio [HR], 0.379; 95% confidence interval [CI], 0.190 to0.756; p = 0.006) and 12-month MACE occurrence (4.6% vs. 6.9%; HR, 0.661; 95% CI, 0.457 to 0.956; p = 0.028). However, the benefit of ARBs on 12-month mortality compared with ACEIs was marginal (4.3% vs. 6.2%; HR, 0.684; 95% CI, 0.467 to 1.002; p = 0.051). CONCLUSIONS: Our results suggest that ARBs are not inferior to, and may actually be better than ACEIs in Korean patients with AMI.

Angiotensin II Modulates p130Cas of Podocytes by the Suppression of AMP-Activated Protein Kinase

Angiotensin II (Ang II) induces the pathological process of vascular structures, including renal glomeruli by hemodynamic and nonhemodynamic direct effects. In kidneys, Ang II plays an important role in the development of proteinuria by the modification of podocyte molecules. We have previously found that Ang II suppressed podocyte AMP-activated protein kinase (AMPK) via Ang II type 1 receptor and MAPK signaling pathway. In the present study, we investigated the roles of AMPK on the changes of p130Cas of podocyte by Ang II. We cultured mouse podocytes and treated them with various concentrations of Ang II and AMPK-modulating agents and analyzed the changes of p130Cas by confocal imaging and western blotting. In immunofluorescence study, Ang II decreased the intensity of p130Cas and changed its localization from peripheral cytoplasm into peri-nuclear areas in a concentrated pattern in podocytes. Ang II also reduced the amount of p130Cas in time and dose-sensitive manners. AMPK activators, metformin and AICAR, restored the suppressed and mal-localized p130Cas significantly, whereas, compound C, an AMPK inhibitor, further aggravated the changes of p130Cas. Losartan, an Ang II type 1 receptor antagonist, recovered the abnormal changes of p130Cas suppressed by Ang II. These results suggest that Ang II induces the relocalization and suppression of podocyte p130Cas by the suppression of AMPK via Ang II type 1 receptor, which would contribute to Ang II-induced podocyte injury.

The Effect of Bortezomib on Antibody-Mediated Rejection after Kidney Transplantation

PURPOSE: Recently, bortezomib has been used to treat antibody-mediated rejection (AMR) refractory to conventional treatment such as plasmapheresis, intravenous immunoglobulin, and rituximab. The authors aimed to describe their experiences when bortezomib was used to treat refractory AMR. MATERIALS AND METHODS: Eleven refractory AMR episodes treated with bortezomib were included in this study. The patients received one or two cycles of bortezomib (1.3 mg/m2) on days 1, 4, 8, and 11. RESULTS: Bortezomib effectively reduced antibodies against various targets, including human leukocyte antigen (HLA) class I and II, ABO blood group antigen, and angiotensin II type 1 receptor. Antibodies were depleted or reduced significantly in eight AMR episodes. Overall, there was a significant improvement in the mean estimated glomerular filtration rate (eGFR) at 3 months after therapy (36.91+/-22.15 mL/min/1.73 m2) versus eGFR at time of AMR diagnosis (17.00+/-9.25 mL/min/1.73 m2; p=0.007). All six early-onset AMR episodes (within 6 months post-transplantation) showed full recovery of allograft function. Additionally, three of the five late-onset AMR episodes (>6 months post-transplantation) showed improved allograft function. CONCLUSION: Anti-humoral treatment based on bortezomib might be an effective strategy against refractory AMR caused by various types of antibodies. Notably, this treatment could be more effective in early-onset AMR than in late-onset AMR.

Hipertensão arterial de difícil controle e o polimorfismo A1166C do gene AT1 / Difficult-to-treat hypertension and AT1 A1166C gene polymorphism

Fundamentos: Polimorfismos presentes em genes que codificam proteínas do sistema renina-angiotensina aldosterona (SRAA) estão associados com o quadro de hipertensão arterial sistêmica (HAS) em algumas populações. Estudos demonstram a relação entre o polimorfismo A1166C no gene do receptor tipo 1 da angiotensina II (AT1) com a HAS, mas os dados ainda são controversos. Objetivo: Analisar a presença deste polimorfismo em pacientes portadores de HAS resistente da região dos Campos Gerais (PR), Brasil. Materiais e Métodos: Grupos de pacientes com hipertensão de fácil (G1) (n = 34) e difícil controle medicamentoso (G2) (n = 39) foram analisados quanto ao polimorfismo mencionado, utilizando-se a técnica de Polymerase Chain Reaction­ Restriction Fragment Lenght Polymorphism (PCR-RFLP). Os pacientes foram categorizados em três genótipos: AA, AC e CC. As frequências alélicas e genotípicas foram calculadas para cada grupo e os dados confrontados com as características metabólicas e antropométricas dos indivíduos. Resultados: não houve diferença entre os grupos quanto a sexo e idade. O índice de massa corporal (IMC), pressão arterial sistólica (PAS), diastólica (PAD) e número de anti-hipertensivos utilizados foram maiores no G2. Asfrequências alélicas e genotípicas mostraram-se semelhantes entre os grupos (p > 0,05). Conclusão: Nesta população, este polimorfismo não está associado ao fácil ou difícil controle da pressão arterial (PA). Possivelmente, outros fatores devem estar influenciando a HAS nestes pacientes

Background: Polymorphisms in genes encoding proteins of the renin-angiotensin-aldosterone system (RAAS) are associated with systemic arterial hypertension (SAH) in some populations. Some reports demonstrated the relationship between the angiotensin II type 1 receptor (AT1) A1166C gene polymorphism with SAH, but the data are still controversial. Objective: To analyze the presence of this polymorphism in patients porting difficult-to-treat SAH from Campos Gerais region (PR), Brazil. Materials and Methods: Groups of patients porting hypertension easy (G1) (n = 34) and difficult-to-treat using drugs (G2) (n = 39) were analyzed according to the polymorphism mentioned, using the Polymerase Chain Reaction­ Restriction Fragment Lenght Polymorphism (PCR-RFLP) technique. The patients were categorized into three genotypes: AA, AC and CC. The allele and genotype frequencies were calculated and the results were compared with metabolic and anthropometric characteristics of the patients. Results: There was no difference between groups regarding gender and age. The body mass index (BMI), systolic and diastolic blood pressures and the number of antihypertensive drugs were higher in G2. The allele and genotype frequencies were similar between the groups (p > 0.05). Conclusions: In this population, the polymorphism analyzed is not associated with easy or difficult-to-treat SAH. Possibly, other factors are influencing the hypertension in these patients

Comparison of Inhibitory Effects between Enalapril and Losartan on Adrenal Catecholamine Secretion

BACKGROUND: The present study was attempted to compare enalapril, an angiotensin-converting enzyme inhibitor with losartan an angiotensin II (Ang II) receptor blocker in the inhibitory effects on the secretion of catecholamines (CA) from the perfused model of the rat adrenal gland. METHODS: The adrenal gland was isolated and perfused with Krebs-bicarbonate. CA was measured directly by using the fluorospectrophotometer. RESULTS: Both enalapril and losartan during perfusion into an adrenal vein for 90 minutes inhibited the CA release evoked by acetylcholine (ACh), 1.1-dimethyl-4-phenyl piperazinium (DMPP, a selective Nn agonist), high K+ (a direct membrane-depolarizer), 3-(m-chloro-phenyl-carbamoyl-oxy-2-butynyl-trimethyl ammonium (McN-A-343, a selective M1 agonist), and Ang II in a time-dependent manner. Also, in the presence of enalapril or losartan, the CA release evoked by veratridine (an activator of voltage-dependent Na+ channels), 6-dimethyl-3-nitro-4-(2-trifluoromethyl-phenyl)-pyridine-5-carboxylate (BAY-K-8644, an L-type Ca2+ channel activator), and cyclopiazonic acid (a cytoplasmic Ca2+-ATPase inhibitor) were significantly reduced. Based on the same concentration of enalapril and losartan, for the CA release evoked by ACh, high K+, DMPP, McN-A-343, Ang II, veratridine, BAY-K-8644, and cyclopiazonic acid, the following rank order of inhibitory potency was obtained: losartan > enalapril. In the simultaneous presence of enalapril and losartan, ACh-evoked CA secretion was more strongly inhibited compared with that of enalapril- or losartan-treated alone. CONCLUSIONS: Collectively, these results demonstrate that both enalapril and losartan inhibit the CA secretion evoked by activation of both cholinergic and Ang II type-1 receptors stimulation in the perfused rat adrenal medulla. When these two drugs were used in combination, their effects were enhanced, which may also be of clinical benefit. Based on concentration used in this study, the inhibitory effect of losartan on the CA secretion seems to be more potent than that of enalapril.

Severe Hyponatremia Associated with the Use of Angiotensin II Receptor Blocker/thiazide Combinations

There are several widely used combinations of angiotensin II receptor blocker (ARB)/thiazide. The complimentary mechanism of action for such anti-hypertensive therapies is that, while ARB inhibits the vasoconstricting and aldosterone-secreting effects of angiotensin II, hydrochlorothiazide affects the renal tubular mechanisms of electrolyte reabsorption and increases excretion of sodium and chloride in the distal tubule, consequently promoting water excretion. In addition, hypokalemia, which may be triggered by a hydrochlorothiazide-induced increase in urinary potassium loss, is resisted by the use of ARB. Hence, the ARB/thiazide combination is safe in terms of potassium imbalance. For these reasons, fixed-dose ARB/thiazide combination anti-hypertensive drugs have been widely used for the treatment of hypertension. However, there have not been many studies done regarding cases where patients under such regimens showed severe hyponatremia, even when the amount of thiazide included was low. Here we report two cases in which severe hyponatremia occurred following treatment with the ARB/thiazide combinations. Upon discontinuation of the regimen, both patients showed recovery from hyponatremia.