A aldosterona participa da progressão das doenças renais em modelos experimentais e ensaios clínicos. Considerando que o modelo de hipertensão renovascular 2 rins-1 clipe (2R-1C) é caracterizado pela atividade elevada do sistema renina-angiotensina-aldosterona, o objetivo desse trabalho foi avaliar o papel da aldosterona na lesão renal presente nesse modelo através do bloqueio do receptor mineralocorticóide (RM) com espironolactona. Ratos Wistar foram submetidos ao procedimento cirúrgico para colocação de um clipe de prata na artéria renal esquerda e após 2 semanas do desenvolvimento da hipertensão renovascular 2R-1C, foram divididos em 3 grupos sendo que para o primeiro grupo nenhuma droga foi administrada (n=8), para o segundo grupo foi administrado por via oral 20 mg/Kg/dia de espironolactona (n=10) e para o terceiro, 7 mg/Kg/dia de amilorida (n=12). O peso e a pressão sistólica foram monitorados semanalmente. Coletas de urina (durante 24 h) e sangue foram realizadas em 3 períodos distintos: antes do procedimento cirúrgico; na 2° semana após a cirurgia (antes do início do tratamento) e na 6° semana após a cirurgia (após o término do tratamento). As amostras foram utilizadas para análise de creatinina, osmolalidade, sódio, potássio e albuminúria. Ao final do experimento, os rins foram perfundidos e pesados. Análise histológica para avaliar a extensão das alterações tubulointersticiais foi realizada. Além disso, marcadores de inflamação (ED-1 e p-JNK), de produção de matriz extracelular (fibronectina), de miofibroblastos (-actina de músculo liso) e de transdiferenciação tubular (vimentina) na região tubulointersticial cortical e de lesão nos podócitos (desmina) foram avaliados. O tratamento com espironolactona foi capaz de atenuar o aumento na excreção de albumina, o aumento na concentração plasmática de creatinina e a redução na depuração de creatinina. No rim clipado dos ratos 2R-1C, as lesões tubulointersticias e podocitárias, demonstradas pelos marcadores estudados, foram discretas e a terapia com espironolactona ou amilorida não foi capaz de minimizá-las. Por outro lado, no rim não clipado, a administração de espironolactona atenuou o aumento de matriz extracelular e a lesão nos podócitos. Os efeitos benéficos da espironolactona ocorreram independentes da redução na pressão sanguínea e podem ser em parte, dependentes do bloqueio do canal epitelial de sódio (ENaC). Tais efeitos trazem perspectiva para espironolactona como uma ferramenta terapêutica a ser explorada em pacientes com estenose de artéria renal. / Aldosterone is involved in the progression of renal disease in experimental models and clinical trials. Considering that the model of renovascular hypertension 2 kidney-1 clip (2K-1C) is characterized by a high activity of the renin-angiotensin-aldosterone system, the objective of this study was to assess the role of aldosterone in renal injury in this model by blocking the mineralocorticoid receptor (MR) with spironolactone. Male Wistar rats were submitted to surgery to place a silver clip on the left renal artery and after two weeks of the development of 2K-1C renovascular hypertension they were divided into three groups. The first group was administered no drug (n=8), in the second group spironolactone 20 mg/kg/day was given orally (n=10) and the third group received amiloride 7 mg/kg/day (n=12). Body weight and systolic blood pressure were monitored weekly. Samples of urine (collected for 24 h) and blood were performed in 3 distinct periods: before surgery; 2 weeks after surgery (before treatment) and 6 weeks after surgery (after treatment). The samples were used to analyze creatinine, osmolality, sodium, potassium and albuminuria. At the end of the experiment, the kidneys were perfused and weighed. Histological analysis to assess the extent of tubulointerstitial changes was performed. Additionally, markers of inflammation (ED-1 and p-JNK), production of extracellular matrix (fibronectin), myofibroblasts (-smooth muscle actin) and tubular transdifferentiation (vimentin) in the area of tubulointerstitial cortical and injury in podocytes (desmin) were evaluated. Treatment with spironolactone was able to attenuate the increase in albumin excretion, the increase in plasma concentration of creatinine and the reduction in creatinine clearance. In the clipped kidney, tubulointerstitial and podocytes injuries, demonstrated by markers studied, were discrete and therapy with spironolactone or amiloride was not able to minimize them. However, in the non-clipped kidney, administration of spironolactone attenuated the increase of extracellular matrix and podocyte injury. The beneficial effects of spironolactone occurred independent of the reduction blood pressure and can be partly dependent of epithelial sodium channel (ENaC) blockade. These effects bring perspective to espironolactone as a therapeutic tool to be explored in patients with renal artery stenosis.

Apneia obstrutiva do sono (AOS) é um fator de risco independente para o desenvolvimento de hipertensão arterial sistêmica, principalmente hipertensão arterial resistente, e doenças cardiovasculares. Hipertensão arterial resistente está associada à AOS, níveis elevados de aldosterona e dieta rica em sal. O objetivo do presente estudo foi determinar se a quantidade de sal na dieta e os níveis de aldosterona estão associados com a intensidade da AOS em pacientes com hipertensão arterial resistente. Noventa e sete pacientes com hipertensão arterial resistente foram avaliados com polissonografia noturna assistida e dosagem de aldosterona e sódio em urina coletada por 24h durante a dieta habitual. Hiperaldosteronismo foi definido como atividade da renina plasmática < 1 ng/mL/h e aldosterona urinária >= 12 ?g/24h. Na população total estudada, a média de idade foi 55±9 anos e 47,4% dos pacientes eram do sexo masculino. Em média, os pacientes estavam em uso de 4,3±1,1 medicamentos anti-hipertensivos e a pressão arterial foi 156,3±22,4/88,9±13,3 mmHg. A prevalência de AOS foi de 77,3% na população total estudada. Vinte e oito (28,9%) pacientes foram diagnosticados como portadores de hiperaldosteronismo. A prevalência de AOS foi maior nos pacientes com do que nos pacientes sem hiper-aldosteronismo (82,1% vs 75,4%), mas sem significância estatística. A análise univariada na população total demonstrou que o índice de apneia-hipopneia correlacionou-se positiva e significantemente com a circunferência do pescoço (rho=0,4362, p<0,0001) e com o sódio urinário (rho=0,2269, p=0,0254). Sexo masculino, circunferência do pescoço e sódio urinário estiveram positiva e significantemente associados ao índice de apneia-hipopneia em pacientes com hiperaldosteronismo. Nenhuma das variáveis selecionadas se associou com o índice de apneia-hipopneia entre os pacien-tes sem hiperaldosteronismo. Em conclusão, níveis elevados de aldosterona e dieta com sal estão associados com a severidade da AOS em pacientes com hipertensão arterial resistente. Esses achados sugerem que a restrição de sal na dieta pode ser uma estratégia terapêutica para a redução da severidade da AOS em pacientes com hipertensão arterial resistente e hiperaldosteronismo. / Obstructive sleep apnea is a strong and independent risk factor for the development of hypertension, particularly resistant hypertension, and cardiovascular diseases. Patients with resistant hypertension have a high prevalence of obstructive sleep apnea in association with elevated aldosterone levels and high salt intake. The objective was to determine if dietary salt and aldosterone levels are associated with severity of obstructive sleep apnea in patients with resistant hypertension. Ninety-seven patients with resistant hypertension were evaluated by overnight polysomnography and 24-hour urinary sodium excretion and aldosterone while ingesting their usual diet. Hyperaldosteronism was defined as plasma renin activity <1 ng/mL/h and urinary aldosterone >= 12 ?g/24 h. Overall, mean age was 55±9 years and 47.4% were males. Mean clinic blood pressure was 156.3±22.4/88.9±13.3 mmHg on an average 4.3±1.1 antihypertensive medications. Prevalence of obstructive sleep apnea was 77.3% within the entire population. Twenty-eight (28.9%) of patients were diagnosed with hyperaldosteronism. The prevalence of obstructive sleep apnea tended to be higher in patients with than without (82.1% vs 75.4%) hyperaldosteronism, but the difference did not reach statistical significance. In the univariate analysis among all patients, apnea-hypopnea index correlated significantly with neck circumference (rho=0.4362, p<0.0001) and urinary sodium excretion (rho=0.2269, p=0.0254). Gender, neck circumference and urinary sodium excretion were positively and significantly associated with apnea-hypopnea index in patients with hyperaldosteronism. None of the selected variables were associated with apnea-hypopnea index in patients without hyperaldosteronism. In conclusion, the current findings suggest that both aldosterone and dietary salt are related to severity of obstructive sleep apnea in patients with resistant hypertension. Our results support dietary salt restriction as a treatment strategy for reduction of obstructive sleep apnea severity in patients with resistant hypertension and hyperaldosteronism.

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2017-01-24T16:23:42Z No. of bitstreams: 1 2015 - Eriane de Lima Caminotto.pdf: 1339748 bytes, checksum: 753de2c181b04ca05748c103c2d6ec8b (MD5) / Made available in DSpace on 2017-01-24T16:23:42Z (GMT). No. of bitstreams: 1 2015 - Eriane de Lima Caminotto.pdf: 1339748 bytes, checksum: 753de2c181b04ca05748c103c2d6ec8b (MD5) Previous issue date: 2015-10-21 / Funda??o Carlos Chagas Filho de Amparo ? Pesquisa do Estado do RJ - FAPERJ / Glaucoma is a disease that causes more blindness in dogs and has no cure, only treatment. The difficulty in the drainage of aqueous humor (AH) results in an increase in intraocular pressure (IOP), representing a significant risk factor for the occurrence of this condition, leading to irreversible damage to the progressive loss of visual field and vision as a whole death of retinal ganglion cells (RGC), loss of axons in the optic nerve and excavation of the same. In addition to this, several mechanisms may contribute to the development and progression of this disease, for example, unbalances of the renin-angiotensin-system (RAS), and cardiovascular and renal diseases. The measurement of IOP and the examination of the fundus are the methods used to diagnose this condition. The treatment of choice is based on eye drops that stimulate drainage of HA and / or decrease their production resulting in IOP control; however in many cases the treatment does not attain the desired effect, culminating in blindness. In an attempt to change this therapeutic perspective, this study compared, in healthy and normotensive Beagle dogs, systemic and ocular action of three drugs: timolol maleate 0.5% (non-selective beta-blocker used in cases of glaucoma) , captopril 0.1% and 0.5% (ECA1 inhibitor never before studied in greater concentration in dogs) and aceturato of diminazene - DIZE 0.1% and 0.5% (endogenous activator of ACE2, never before researched in eyes canines). The latter two drugs were formulated for ophthalmic use for the reduction of IOP, since it is known about the existence of SARS eye level, and that they have been successfully administered systemically at reducing systemic arterial pressure (SAP). Thus, before and after treatment, 18 dogs underwent the Schirmer Tear Test (TLS1) and blood collection for measuring the concentration of angiotensin-converting enzyme (ECA1) serum. For three consecutive days before treatment and at three times (6h, 12h and 18h) all animals have gone through four exams, always following the same order: evaluation of pupil size, IOP measurement, measurement of HR and SAP. After obtaining the normal range, the animals had the left eye subjected to predetermined protocols initially with 1 drop every 12 hours, 7 days a lower concentration and, in the other seven days, in the highest concentration. The adelfos eyes were control and every day in the three different times dogs went through the same initial exams. All drugs were good penetration and no adverse eye level. As for tear production, captopril is the most suitable for glaucoma patients and patients with keratoconjunctivitis sicca, while timolol is contraindicated for them. All decreased IOP values, and in the second week of treatment, with higher concentrations, reductions were more significant. The bradycardia was observed in captopril-treated animals 0.5%, with a reduction of almost 9% in HR compared to captopril in lower concentrations / O glaucoma ? uma das doen?as que mais causa cegueira em c?es e n?o possui cura, apenas tratamento. A dificuldade na drenagem do humor aquoso (HA) resulta no aumento da press?o intra-ocular (PIO) que representa um fator de risco significativo para a ocorr?ncia dessa afec??o, conduzindo ? danos irrevers?veis como a perda progressiva do campo visual e da vis?o como um todo, morte das c?lulas ganglionares da retina (CGR), perda de ax?nios do nervo ?ptico e escava??o do mesmo. Al?m deste, diversos mecanismos podem contribuir para o desenvolvimento e progress?o desta doen?a como, por exemplo, os desequil?brios do sistema-renina-angiotensina (SRA) e as doen?as cardiovasculares e renais. A mensura??o da PIO e o exame do fundo de olho s?o os m?todos mais utilizados para diagnosticar essa afec??o. O tratamento de escolha se baseia em col?rios que estimulam a drenagem do HA e/ou diminuam sua produ??o resultando no controle da PIO; por?m em muitos casos a terapia n?o atinge o efeito desejado e culmina em cegueira. Na tentativa de mudar essa perspectiva terap?utica, o presente trabalho comparou, em c?es sadios e normotensos da ra?a Beagle, a a??o sist?mica e ocular de tr?s f?rmacos: maleato de timolol 0,5% (beta-bloqueador n?o seletivo usado nos casos de glaucoma), captopril 0,1% e 0,5% (inibidor de ECA1 nunca antes estudado nesta maior concentra??o em c?es) e aceturato de diminazeno ? DIZE 0,1% e 0,5% (ativador end?geno de ECA2, nunca antes pesquisado em olhos caninos). Os dois ?ltimos f?rmacos foram formulados para uso oftalmol?gico visando a redu??o da PIO, uma vez que ? sabido sobre a exist?ncia do SRA a n?vel ocular e que os mesmos j? foram administrados sistemicamente com sucesso na redu??o press?o arterial sist?mica (PAS). Dessa forma, antes e ap?s os tratamentos, 18 c?es foram submetidos ao teste lacrimal de Schirmer (TLS1) e ? coleta sangu?nea para dosagem da concentra??o da enzima conversora de angiotensina (ECA 1) do soro.Durante tr?s dias consecutivos antes dos tratamentos e em tr?s hor?rios distintos (6h, 12h, e 18h) todos os animaispassaram por quatro exames, seguindo sempre a mesma ordem: avalia??o do di?metro pupilar, aferi??o da PIO, aferi??o da FC e da PAS.Ap?s a obten??o dos valores normais, os animais tiveram o olho esquerdo submetido aos protocolos pr?-determinados inicialmente com 1 gota, a cada 12 horas, por 7 dias na menor concentra??o e, nos demais 7 dias, na maior concentra??o. Os olhos adelfos foram o controle e, todos os dias nos tr?s hor?rios distintos os c?es passaram pelos mesmos exames iniciais. Todos os f?rmacos tiveram boa penetrabilidade e aus?ncia de efeitos adversos a n?vel ocular. Quanto ? produ??o lacrimal, o captopril ? o mais indicado para os pacientes glaucomatosos e portadores de ceratoconjuntivite seca, enquanto que o timolol ? contra-indicado para os mesmos. Todos diminu?ram os valores da PIO, sendo que na segunda semana de tratamento, com concentra??es maiores, as redu??es foram mais significativas. A bradicardia foi observada nos animais tratados com captopril 0,5%, com uma redu??o de quase 9% na FC, quando comparado com o captopril em menor concentra??o.

Introdução: O hiperaldosteronismo primário (HP) é a causa mais comum de hipertensão arterial sistêmica (HAS) secundária, com prevalência de até 21% em pacientes com HAS resistente. Na última década, foram feitos consideráveis avanços na compreensão da patogênese do HP. Variantes patogênicas somáticas nos genes de canais iônicos KCNJ5, CACNA1D, ATP1A1 e ATP2B3, envolvidos na manutenção da homeostase iônica intracelular, foram descritas em 38%, 9,3%, 5,3% e 1,7% dos tumores, respectivamente. Variantes patogênicas somáticas no gene CTNNB1, fundamental para o desenvolvimento do córtex da suprarrenal, foram também identificadas em aproximadamente 5% dos aldosteronomas. Mais recentemente, uma variante germinativa no gene CACNA1H, que codifica a subunidade Alfa1H do canal de cálcio Cav 3.2, foi identificada em um paciente com aldosteronoma. Objetivos: O objetivo geral desse projeto foi investigar as bases genéticas do HP causado por aldosteronoma. Os objetivos específicos foram: 1) Investigar variantes patogênicas somáticas nos genes KCNJ5, ATP1A1, ATP2B3 e CTNNB1 em aldosteronomas de indivíduos com HP; 2) Sequenciar o exoma (pareado sangue e tumor) dos casos de HP causados por aldosteronoma, negativos para variantes nos genes citados acima; 3) Correlacionar o genótipo com os parâmetros clínicos e hormonais dos pacientes com aldosteronomas. Métodos: As regiões hot-spot dos genes KCNJ5, ATP1A1, ATP2B3 e CTNNB1 foram sequenciadas por Sanger em 62 tumores [56% mulheres; mediana de idade ao diagnóstico 50 anos (variação, 20 a 68)]. Pacientes sem variantes patogênicas somáticas nos genes descritos acima foram submetidos a genotipagem do exoma (pareado sangue e tecido) por sequenciamento paralelo em larga escala (HiSeq 2500, Illumina). Variantes germinativas raras (MAF < 0,01% no 1000 genomes, ExAC, gnomAD e AbraOM) em genes codificadores de canais iônicos ou associados a hiperplasia adrenal foram selecionadas para segregação familial. Resultados: Variantes patogênicas somáticas em heterozigose foram encontradas em 34 de 62 (54,8%) aldosteronomas. As variantes identificadas nos genes KCNJ5, ATP1A1, ATP2B3 e CTNNB1 eram previamente conhecidas. Variantes patogênicas no KCNJ5 foram detectadas em 28 de 62 (45,2%) aldosteronomas. Duas variantes recorrentes foram encontradas: p.Gly151Arg em 13 de 28 (46%) e p.Leu168Arg em 14 de 28 (50%) tumores. A variante patogênica p.Glu145Gln do KCNJ5 foi identificada em um (4%) aldosteronoma. Adicionalmente, a variante patogênica p.Leu104Arg do ATP1A1 foi detectada em 2 (3,2%) aldosteronomas; a variante patogênica p.Leu425_Val426del do ATP2B3 em um (1,6%) caso e a variante patogênica p.Ser45Pro do CTNNB1 em 2 (3,2%) aldosteronomas. Uma nova variante p.Leu276Pro somática em heterozigose no CACNA1D foi identificada em um aldosteronoma no exoma e classificada como provavelmente patogênica. Aldosteronomas com variantes patogênicas no KCNJ5 foram diagnosticados mais frequentemente em mulheres (p= 0,047) e em idades mais jovens (p= 0,002) quando comparado com tumores sem variantes no KCNJ5. O tamanho do nódulo foi maior em aldosteronomas com variantes patogênicas no KCNJ5 (p= 0,0001). O percentual de pacientes com tempo de HAS < 5 anos foi similar nos dois grupos. A remissão pós-operatória da HAS foi observada em 50% dos pacientes com tumor contendo variante patogênica no KCNJ5, enquanto apenas 15% dos pacientes com tumor sem variante no KCNJ5 tiveram remissão da HAS (p= 0,003). Na análise multivariada, somente a presença de variante patogênica somática no KCNJ5 foi um preditor independente de remissão da HAS (p= 0,03). Após filtragem das variantes encontradas no sequenciamento exômico, quatro variantes germinativas missense em heterozigose foram consideradas deletérias em mais de 3 algoritmos de predição in silico: 1) uma nova variante (p.Pro559Thr) no gene CACNA1H, já associado ao fenótipo de HP; 2) a variante p.Arg178Cys no gene CACNA1I, que codifica a subunidade Alfa 1I do canal Cav 3.3; 3) a variante p.Glu52Ala no gene ATP13A3, que codifica uma proteína transmembrana da família de proteínas ATPase do tipo P; 4) a variante p.Tyr507Ser no gene KCNC4, que codifica o canal de potássio Kv 3.4. Conclusão: Foi caracterizado o espectro de variantes patogênicas somáticas em uma coorte brasileira de tumores corticais adrenais produtores de aldosterona, bem como o impacto das variantes no KCNJ5 na predição de remissão da HAS após adrenalectomia. Além disso, foram identificados novos genes candidatos provavelmente relacionados a patogênese do HP causado por aldosteronomas / Introduction: Primary aldosteronism (PA) is the most common form of secondary hypertension (HT), with a prevalence of approximately 20% in patients with resistant hypertension. In the last decade, somatic mutations in KCNJ5, CACNA1D, ATP1A1 and ATP2B3 genes, which are involved in maintaining intracellular ionic homeostasis and cell membrane potential, were described in 38%, 9.3%, 5.3% and 1.7% of aldosterone-producing adenomas (APAs), respectively. All these mutations lead to the activation of calcium signaling, the major trigger for aldosterone production. Additionally, somatic activating mutations in exon 3 of CTNNB1 gene, which is involved in the adrenocortical development, were identified in approximately 5% of APAs. More recently, the germline p.V1951G CACNA1H variant was described in a PA patient with an APA. Aims: To investigate the genetics of APAs. The specific aims of this study were: 1) To investigate somatic variants in KCNJ5, ATP1A1, ATP2B3 and CTNNB1 genes in APAs from PA patients; 2) To perform exome sequencing of PA patients caused by APAs without mutations in those genes already associated with PA; 3) To correlate genetic findings and clinical parameters. Methods: Hot-spot regions of KCNJ5, ATP1A1, ATP2B3 e CTNNB1 genes were sequenced by Sanger in 62 APAs [56% women; median of age at diagnosis 50 yrs (range, 20 to 68)]. We performed whole exome sequencing (HiSeq 2500, Illumina) in paired blood and tumor DNA samples from 10 unrelated subjects with PA caused by APAs without somatic mutations in hot-spot regions of KCNJ5, ATP1A1, ATP2B3 and CTNNB1.We searched for rare germline coding variants (MAF < 0.01% in 1000 genomes, ExAC, gnomAD and AbraOM) in ionchannel genes, which are expressed in normal adrenal tissue, or in genes previously related to adrenal hyperplasia. Results: Pathogenic somatic heterozygous variants were identified in 34 out of 62 (54.8%) APAs. KCNJ5 pathogenic variants were detected in 28 out of 62 (45.2%) APAs. Two recurrent variants were found in KCNJ5: the p.Gly151Arg in 13 out of 28 (46%) and the p.Leu168Arg in 14 out of 28 (50%) APAs. KCNJ5 pathogenic variant p.Glu145Gln was identified in one (4%) APA. In addition, the p.Leu104Arg ATP1A1 mutation was detected in two APAs (3.2%); the p.Leu425_Val426del ATP2B3 mutation in one APA (1.6%); and the p.Ser45Pro CTNNB1 mutation in two APAs (3.2%). The novel CACNA1D somatic heterozygous variant p.Leu276Pro (likely pathogenic) was identified by exome sequencing in one APA. APAs with KCNJ5 pathogenic variants were diagnosed more often in women (p= 0.047) and at younger ages (p= 0.002) when compared to APAs without KCNJ5 variants. Nodule size was larger in APAs with KCNJ5 pathogenic variants (p= 0.0001). The frequency of PA patients com HT duration < 5 yrs was similar in both groups. HT remission was observed in 50% of patients with APAs harboring KCNJ5 pathogenic variants, whereas only 15% of patients with APAs without KCNJ5 pathogenic variants had HT remission (p= 0.003). In multivariate analysis, only the presence of a KCNJ5 pathogenic variant was an independent predictor of HT remission (p= 0.03). After exome sequencing analysis, four germline missense heterozygous variants predicted to be pathogenic in >=3 in silico tools were selected: 1) the novel p.Pro559Thr variant in CACNA1H gene, previously associated with PA phenotype; 2) the p.Arg178Cys variant in CACNA1I gene, which encodes the Alpha 1I subunit of Cav 3.3 channel; 3) the p.Glu52Ala variant in ATP13A3 gene, which is a member of the P-type ATPase family of membrane transport proteins; and 4) the p.Tyr507Ser variant in KCNC4 gene, which encodes the voltage-gated potassium channel Kv 3.4. Conclusion: We have characterized the spectrum of somatic pathogenic variants in a Brazilian cohort of APAs, and evaluated the impact of KCNJ5 somatic pathogenic variants in predicting HT remission after adrenalectomy. In addition, we identified potential novel gene candidates in the pathogenesis of PA caused by APAs

<p>Hypertension is common and constitutes an increased risk of morbidity and mortality of cardiovascular disease. Antihypertensive treatment will reduce this risk; the individual patient's response to treatment, however, is difficult to predict.</p><p>Patients with hypertension and left ventricular hypertrophy were randomized to monotherapy with either the angiotensin II type 1 receptor antagonist irbesartan or the beta-adrenoreceptor blocker atenolol, and followed for three months. The aim was to determine whether gene polymorphisms in the renin-angiotensin-aldosterone system were related to the response to treatment.</p><p>The ACE II genotype was associated with the most pronounced diastolic blood pressure response, while the aldosterone synthase (CYP11B2) -344 TT genotype showed the greatest systolic blood pressure response. The angiotensinogen 174 TM genotype showed the most pronounced regression in left ventricular mass, independent of the change in blood pressure. These associations were exhibited only in response to treatment with the angiotensin II type 1 receptor antagonist irbesartan.</p><p>In a sample of apparently healthy subjects, those with both the D allele and the angiotensinogen 174 TM variant in combination showed a decreased endothelium-dependent vasodilation.</p><p>These results suggest that the response to antihypertensive treatment is associated with polymorphisms in the genes reflective of the pathophysiological pathway the drug targets. The present study is an encouragement for future investigation, such as large scale studies of multiple polymorphisms and combinations thereof in an attempt to identify a panel of genotypes that can be used as a predictor of an individual patient's response to anithypertensive treatment.</p>

Hypertension is common and constitutes an increased risk of morbidity and mortality of cardiovascular disease. Antihypertensive treatment will reduce this risk; the individual patient's response to treatment, however, is difficult to predict. Patients with hypertension and left ventricular hypertrophy were randomized to monotherapy with either the angiotensin II type 1 receptor antagonist irbesartan or the beta-adrenoreceptor blocker atenolol, and followed for three months. The aim was to determine whether gene polymorphisms in the renin-angiotensin-aldosterone system were related to the response to treatment. The ACE II genotype was associated with the most pronounced diastolic blood pressure response, while the aldosterone synthase (CYP11B2) -344 TT genotype showed the greatest systolic blood pressure response. The angiotensinogen 174 TM genotype showed the most pronounced regression in left ventricular mass, independent of the change in blood pressure. These associations were exhibited only in response to treatment with the angiotensin II type 1 receptor antagonist irbesartan. In a sample of apparently healthy subjects, those with both the D allele and the angiotensinogen 174 TM variant in combination showed a decreased endothelium-dependent vasodilation. These results suggest that the response to antihypertensive treatment is associated with polymorphisms in the genes reflective of the pathophysiological pathway the drug targets. The present study is an encouragement for future investigation, such as large scale studies of multiple polymorphisms and combinations thereof in an attempt to identify a panel of genotypes that can be used as a predictor of an individual patient's response to anithypertensive treatment.

High salt intake contributes to the development of hypertension in salt-sensitive humans and animals and the mechanistic causes are poorly understood. In Dahl salt-sensitive (S) but not salt-resistant (R) rats, high salt diet increases cerebrospinal fluid (CSF) [Na+] and activates an aldosterone-mineralocorticoid receptor-epithelial sodium channel-endogenous ouabain (MR-ENaC-EO) neuromodulatory pathway in the brain that enhances the activity of sympatho-excitatory angiotensinergic and glutamatergic pathways, leading to an increase in sympathetic nerve activity (SNA) and blood pressure (BP). We hypothesize that high salt diet in Dahl S rats enhances Ang II release in the paraventricular nucleus (PVN), causing a decrease in local nitric oxide (NO) action and an increase in local glutamate release thereby elevating SNA, BP and heart rate (HR). The present study evaluated the effects of agonists or blockers of MR, ENaC, EO, nitric oxide synthase (NOS) or glutamate and AT1-receptors on the BP and HR responses to acute infusions of Na+ rich aCSF, intracerebroventricularly (icv), or in the PVN of Dahl S, R or Wistar rats or to high salt diet in Dahl S and R rats. In Wistar rats, aldosterone in the PVN enhanced the BP and HR responses to infusion of Na+ rich aCSF in the PVN, but not in the CSF, and only the enhancement was prevented by blockers of MR, ENaC and EO in the PVN. AT1-receptor blockers in the PVN fully blocked the enhancement by aldosterone and the responses to infusion of Na+ rich aCSF icv, or in the PVN. Na+ rich aCSF in the PVN caused larger increases in BP and HR in Dahl S vs. R rats and the responses to Na+ were fully blocked by an AT1-receptor blocker in the PVN. BP and HR responses to a NOS blocker in the PVN were the same, but L-NAME enhanced Na+ effects more in Dahl R than S rats. High salt diet attenuated increases in BP from L-NAME in the PVN of Dahl S but not R rats. AT1 and glutamate receptor blockers candesartan and kynurenate in the PVN decreased BP in Dahl S but not R rats on high salt diet. At the peak BP response to candesartan, kynurenate in the PVN further decreased BP whereas candesartan did not further decrease BP at the peak BP response to kynurenate. Our findings indicate that both an acute increase in CSF [Na+] and high salt intake in Dahl S rats increases AT1-receptor activation and decreases NO action in the PVN thereby contributing to the pressor responses to Na+ and presumably, to dietary salt-induced hypertension. The increased BP response to AT1-receptor activation in the PVN of Dahl S is mediated by enhanced local glutamate receptor activation. An MR-ENaC-EO pathway in the PVN can be functionally active and further studies need to assess its role in Dahl S rats on high salt intake.

Despite years of research, the role that hypovolemia plays in orthostatic intolerance after head down bed rest (BR) and spaceflight remains unclear. Additionally, the efficacy of oral saline countermeasures, employed in an attempt to restore plasma volume (PV) after BR is questionable. Several previous studies have suggested that a new homeostatic set point is achieved in space or during BR, making attempts to restore PV temporary at best. We tested the hypotheses that one day of BR would induce a transient increase in PV followed by hypovolemia and new hormonal balance; that a salt tablet and water fluid loading (FL) countermeasure would be ineffective in restoring PV; and also that the FL would not attenuate the exaggerated hormonal responses to orthostatic stress that are expected after 28hr of BR. Plasma volume, serum sodium and osmolarity, and plasma ANP, AVP, renin, angiotensin II, aldosterone, and catecholamines were measured in nine male subjects undergoing 5 different protocols (28hr Bed Rest without Fluid Loading = 28NFL, 28hr Bed Rest with Fluid Loading = 28FL, 4hr Seated Control = 4NFLS, 4hr Seated Control with Fluid Loading = 4FLS, and 4hr Bed Rest = 4BR) in a randomized repeated measures design. The FL countermeasure was 15 ml/kg of body weight of water with 1g of NaCl per 125ml of water. Orthostatic testing by lower body negative pressure (LBNP) was performed before and after all protocols. In agreement with our first hypothesis, we observed transient reductions in renin, angiotensin II, and aldosterone, which after 25.5hr were restored to baseline, slightly augmented, and suppressed, respectively. Also after 25.5hr, PV was reduced in the 28hr BR protocols and was not restored in 28FL; however, the FL protocol increased PV during 4FLS. We additionally observed augmented renin and aldosterone responses, as well as generally elevated angiotensin II after 28NFL, but not after 28FL or any of the 4hr protocols. Furthermore, no changes in plasma norepinephrine responses to LBNP were documented from Pre-Post test in any protocol. Our results indicate that: 1) PV is reduced after short term BR and is not restored by an oral FL; 2) renin-angiotensin-aldosterone system (RAAS) responses to orthostatic stress are augmented after 28hr of BR and the amplified response can be abrogated by FL; and 3) plasma norepinephrine responses during orthostatic stress are not affected by BR or FL, suggesting that RAAS activity may be modulated by FL independently of sympathetic activity and PV during orthostasis after bed rest.

Despite years of research, the role that hypovolemia plays in orthostatic intolerance after head down bed rest (BR) and spaceflight remains unclear. Additionally, the efficacy of oral saline countermeasures, employed in an attempt to restore plasma volume (PV) after BR is questionable. Several previous studies have suggested that a new homeostatic set point is achieved in space or during BR, making attempts to restore PV temporary at best. We tested the hypotheses that one day of BR would induce a transient increase in PV followed by hypovolemia and new hormonal balance; that a salt tablet and water fluid loading (FL) countermeasure would be ineffective in restoring PV; and also that the FL would not attenuate the exaggerated hormonal responses to orthostatic stress that are expected after 28hr of BR. Plasma volume, serum sodium and osmolarity, and plasma ANP, AVP, renin, angiotensin II, aldosterone, and catecholamines were measured in nine male subjects undergoing 5 different protocols (28hr Bed Rest without Fluid Loading = 28NFL, 28hr Bed Rest with Fluid Loading = 28FL, 4hr Seated Control = 4NFLS, 4hr Seated Control with Fluid Loading = 4FLS, and 4hr Bed Rest = 4BR) in a randomized repeated measures design. The FL countermeasure was 15 ml/kg of body weight of water with 1g of NaCl per 125ml of water. Orthostatic testing by lower body negative pressure (LBNP) was performed before and after all protocols. In agreement with our first hypothesis, we observed transient reductions in renin, angiotensin II, and aldosterone, which after 25.5hr were restored to baseline, slightly augmented, and suppressed, respectively. Also after 25.5hr, PV was reduced in the 28hr BR protocols and was not restored in 28FL; however, the FL protocol increased PV during 4FLS. We additionally observed augmented renin and aldosterone responses, as well as generally elevated angiotensin II after 28NFL, but not after 28FL or any of the 4hr protocols. Furthermore, no changes in plasma norepinephrine responses to LBNP were documented from Pre-Post test in any protocol. Our results indicate that: 1) PV is reduced after short term BR and is not restored by an oral FL; 2) renin-angiotensin-aldosterone system (RAAS) responses to orthostatic stress are augmented after 28hr of BR and the amplified response can be abrogated by FL; and 3) plasma norepinephrine responses during orthostatic stress are not affected by BR or FL, suggesting that RAAS activity may be modulated by FL independently of sympathetic activity and PV during orthostasis after bed rest.

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