Submitted in fulfillment of the Degree of Masters in Technology: Clinical Technology, Durban University of Technology, 2011. / Background: Idiopathic dilated cardiomyopathy (IDC) is a primary myocardial disease of unknown cause characterized by left ventricular or biventricular dilatation and impaired myocardial contractility. Idiopathic dilated cardiomyopathy (IDC) is the second commonest cause of heart failure in Africa. Some patients with idiopathic dilated cardiomyopathy present with significant pulmonary hypertension (PHT) which maybe out of keeping with the usual degree of PHT seen in patients with this disorder. Methods and Material: This is a prospective and longitudinal follow-up study of 66 patients with IDC who were evaluated after satisfying the inclusion and exclusion criteria of this study. The clinical evaluation of each patient included a complete medical history, physical examination, 12 lead electrocardiogram, 2D-echocardiography, continuous wave (CW), pulsed wave (PW), and tissue Doppler imaging (TDI). Results: The mean age of all patients was 48.5 ± 12.8, with 39/66 (59.1%) patients being male. The prevalence of pulmonary arterial hypertension (PAH) was documented in 47 patients (71.2%, 95% CI: 59 - 83%). Mean left ventricular ejection fraction (LVEF) was 25.3 ± 8.8%, and mean left atrial volume index (LA volume) was 44.5±19.8 ml/m2. Mitral regurgitation (MR) occurred in 56/66 (84.8%) of patients with moderate or severe MR detected in 60.6% of all cases of IDC. The presence of a tricuspid regurgitant jet was found in 56/66 (84.9%), with (95% CI: 75 -93%). Right ventricular dilatation was found in 65/66 (98.5%), with (95% CI: 95 - 101%). ii Age, LA volume, LVEF and MR were included into a multivariate logistic regression model to predict PAH. Only MR presence was independently associated with PAH adjusted (OR 6.02, 95% CI: 1.15- 31.47) (p= 0.03). Conclusion: The study has shown that there is a significant prevalence of pulmonary arterial hypertension (PAH), right heart involvement and tricuspid regurgitant jet in IDC patients. The present study also showed that in patients with dilated cardiomyopathy, the degree of mitral regurgitation was a good predictor of PAH.

Pulmonary hypertension (PH), when it complicates sarcoidosis, carries a poor prognosis, in part because it is difficult to detect early in patients with worsening respiratory symptoms. Pathogenesis of sarcoidosis occurs via incompletely characterized mechanisms that are distinct from the mechanisms of pulmonary vascular remodeling well known to occur in conjunction with other chronic lung diseases. To address the need for a biomarker to aid in early detection as well as the gap in knowledge regarding the mechanisms of PH in sarcoidosis, we used genome-wide peripheral blood gene expression analysis and identified an 18-gene signature capable of distinguishing sarcoidosis patients with PH (n = 8), sarcoidosis patients without PH (n = 17), and healthy controls (n = 45). The discriminative accuracy of this 18-gene signature was 100% in separating sarcoidosis patients with PH from those without it. If validated in a large replicate cohort, this signature could potentially be used as a diagnostic molecular biomarker for sarcoidosis-associated PH.

Advances in the imaging techniques of the heart have fueled the interest in understanding of right heart pathology. Recently, speckle tracking echocardiography has shown to aid in understanding various right heart diseases and better management. Its role is well established in diagnosing right heart failure, pulmonary artery hypertension, arrhythmogenic right ventricular dysplasia and congenital heart disease. We review the basic mechanics of speckle tracking and analyze its role in various right heart conditions.

Several human diseases have been associated with mitochondria! voltage-dependent anion channel-1 (VDAC1) due to its role in calcium ion transportation and apoptosis. Recent studies suggest that VDAC1 may interact with endothelium-dependent nitric oxide synthase (eNOS). Decreased VDAC1 expression may limit the physical interaction between VDAC1 and eNOS and thus impair nitric oxide production, leading to cardiovascular diseases, including pulmonary arterial hypertension (PAH). In this report, we conducted meta-analysis of genome-wide expression data to identify VDAC1 influenced genes implicated in PAH pathobiology. First, we identified the genes differentially expressed between wild-type and Vdac1 knockout mouse embryonic fibroblasts in hypoxic conditions. These genes were deemed to be influenced by VDAC1 deficiency. Gene ontology analysis indicates that the VDAC1 influenced genes are significantly associated with PAH pathobiology. Second, a molecular signature derived from the VDAC1 influenced genes was developed. We suggest that, VDAC1 has a protective role in PAH and the gene expression signature of VDAC1 influenced genes can be used to i) predict severity of pulmonary hypertension secondary to pulmonary diseases, ii) differentiate idiopathic pulmonary artery hypertension (IPAH) patients from controls, and iii) differentiate IPAH from connective tissue disease associated PAH.

INTRODUÇÃO: Existem várias doenças que evoluem com hipertensão pulmonar (HP), entre elas a Hipertensão Arterial Pulmonar Idiopática (HAPI) e a Esquistossomose. Acredita-se que um dos principais fatores desencadeantes da HP esteja relacionado com a disfunção endotelial. OBJETIVOS: 1. Avaliar a disfunção endotelial de pacientes com HAPI e esquistossomóticos com e sem HAP usando os marcadores plasmáticos Endotelina-1, Selectina E, VEGF, PDGFAB e PDGF-BB; 2.Avaliar se pacientes com HAP associada à esquistossomose possuem o mesmo grau de disfunção endotelial que pacientes com esquistossomose sem HAP. METODOLOGIA: Foram formados 4 grupos distintos: Controle (n=13), HAPI (n=11), pacientes com esquistossomose e HP (ESQ+HP) (n=13) e pacientes com esquistossomose sem HP (ESQ)(n=13). Os pacientes foram submetidos a avaliação clínica (caracterizados quanto a gravidade), funcional (realizaram ecocardiograma com medida de pressão sistólica de ventrículo direito, ultrassonografia abdominal quando indicada e exames para excluir outras doenças) e laboratorial (entre eles, contagem de leucócitos, plaquetas e dosagem de BNP). A avaliação hemodinâmica foi realizada nos pacientes com HP. Para a análise da disfunção endotelial, foram coletados 40 mL de sangue de todos os indivíduos para a dosagem de Endotelina-1, Selectina E, VEGF, PDGF-AB e PDGF-BB. RESULTADOS: Observou-se que os grupos não se diferiram quanto a idade, houve um predomínio do sexo feminino e os grupos controle e ESQ apresentaram valores de PSVD menores do que os grupos com HP (controles: 23,4±4,6, ESQ: 29,5±8,5, HAPI: 79,8±26,4 e ESQ+HP: 75,2±15,3 mmHg). As medidas hemodinâmicas foram semelhantes em ambos os grupos com HAP. Quanto aos marcadores da função endotelial, o grupo controle apresentou valores séricos de PDGF-BB mais aumentados (8,9±4,8x 103 pg/mL, p<0,001) que os grupos HAPI, ESQ+HP, ESQ (3,7±2,1; 5,2±3 ; 2,4±1,7 x 103 pg/mL, respectivamente). O grupo HAPI apresentou valores mais elevados de Selectina E (61,5±24,2 x 103 pg/mL) que os grupos controle, ESQ+HP e ESQ (14,5±12,2; 23,9±15,3; 21,4±18 x 103 pg/mL, respectivamente, p=0,005). Os valores séricos de PDGF-AB do grupo controle foram mais elevados que no grupo ESQ (p=0,006). Não foram encontradas diferenças significantes nos valores séricos de Endotelina-1 entre os grupos (p=0,281). Em relação ao VEGF, os pacientes com HAPI apresentaram valores séricos similares ao grupo ESQ+HP e mais elevados que o grupo controle e ESQ (p=0,002). O ponto de corte da dosagem da selectina E (43.806 pg/mL) para diferenciar pacientes com HAPI dos pacientes com ESQ+HP apresentou uma sensibilidade de 91% e a especificidade de 89%. O PDGF-BB apresentou uma boa acurácia para distinguir o grupo controle dos demais, com uma sensibilidade de 77% e uma especificidade de 83%. Além disso, a Selectina E apresentou uma forte correlação com o níveis séricos de BNP (r=0,74, p=0,006). O número de leucócitos e de plaquetas foram diferentes entre os três grupos do estudo. Pacientes com HAPI tinham maior número de leucócitos e plaquetas quando comparados com esquistossomóticos. CONCLUSÕES: 1.Pacientes com HAPI apresentaram valores séricos mais elevados de Selectina E do que pacientes com esquistossomose e controles; 2.Pacientes portadores de esquistossomose com e sem HP apresentaram os mesmos valores séricos dos marcadores de disfunção endotelial / INTRODUCTION: There are several diseases that cause Pulmonary hypertension (PH), such as Idiopathic Pulmonary Arterial Hypertension and Schistosomiasis. The mechanisms that lead to PH are thought to be related to endothelial dysfunction. OBJECTIVES: To evaluate endothelial dysfunction, using plasma markers such as Endothelin-1(ET-1), E-Selectin, VEGF, PDGF-AB and -BB, in patients with idiopathic pulmonary arterial hypertension (IPAH) and schistosomiasis patients with or without PH; and to evaluate if schistosomiasis groups have endothelial dysfunction in the same degree. METHODOLOGY: Patients were divided in 4 different groups: Patients with IPAH (n=11), Patients with PH associated to Schistosomiasis (SchPH)(n=13), Patients with Schistosomiasis without PH (Sch)(n=13) and Controls(n=13). PAH patients were classified according to severity. All groups were submitted to echocardiography and right ventricule systolic pressure(RVSP) was measured. Abdominal ultrassonography was used to rule in or rule out schistosomiasis diagnosis. PH patients went through haemodynamics evaluation and all patients had laboratorial assessment (leucocytes and platelet count and BNP levels) Soluble adhesion molecules such as E-Selectin, VEGF, PDGF-AB, PDGF-BB e ET-1 were determined by ELISA. Leucocytes and platelet counts as well as BNP levels were also evaluated. Results: Subjects did not differ according to age and there was a higher proportion of female patients. Controls and Sch subjects had lower RVSP compared to PH groups (Sch: 23.4±4.6, controls: 29.5±8.5, IPAH: 79.8±26.4 and Sch+HP: 75.2±15.3 mmHg). Haemodynamics data did not differ in PH patients. In IPAH group, E-selectin was elevated (61.5±24,2x103pg/mL) compared to controls, Sch+HP and Sch (14.5±12.2; 23.9±15.3; 21.4±18 x103pg/mL, respectively, p=0,005). PDGF-BB was decreased in IPAH, Sch+HP, Sch (3.7±2.1; 5.2±3; 2.4±1.7x103pg/mL, respectively) compared to controls (8.9±4.8x 103 pg/mL, p<0.001). PDGF-AB was elevated in controls (25.6±8.6x103pg/mL) when compared to Sch (11.4±8.6 x103pg/mL)(p=0.006). There were no differences in ET-1 levels within groups. In relation to VEGF, IPAH group had higher levels compared to controls and Sch (96,6±68,2, 38,4±28, 37,±19,2 pg/mL, respectively) (p=0,002). Based on ROC curve, E-selectin cutoff value of 43.806 pg/mL showed a sensitivity of 91% and a specificity of 89% to distinguish IPAH patients from other groups and PDGF-BB had a good accuracy to differentiate controls with a sensitivity of 77% and a specificity of 83%. Furthermore, E-selectin had a strong correlation with BNP levels (r=0,74, p=0,006). The number of leucocytes and platelets were different within groups. IPAH patients had the highest, and Sch group had the lowest blood cells and platelets count. Conclusions: 1. IPAH patients had higher levels of serum E-selectin and VEGF and controls had higher levels of PDGF-BB and AB; 2. Schistosomiasis patients with or without PH had the same levels of endothelial dysfunction serum markers

INTRODUÇÃO: Existem várias doenças que evoluem com hipertensão pulmonar (HP), entre elas a Hipertensão Arterial Pulmonar Idiopática (HAPI) e a Esquistossomose. Acredita-se que um dos principais fatores desencadeantes da HP esteja relacionado com a disfunção endotelial. OBJETIVOS: 1. Avaliar a disfunção endotelial de pacientes com HAPI e esquistossomóticos com e sem HAP usando os marcadores plasmáticos Endotelina-1, Selectina E, VEGF, PDGFAB e PDGF-BB; 2.Avaliar se pacientes com HAP associada à esquistossomose possuem o mesmo grau de disfunção endotelial que pacientes com esquistossomose sem HAP. METODOLOGIA: Foram formados 4 grupos distintos: Controle (n=13), HAPI (n=11), pacientes com esquistossomose e HP (ESQ+HP) (n=13) e pacientes com esquistossomose sem HP (ESQ)(n=13). Os pacientes foram submetidos a avaliação clínica (caracterizados quanto a gravidade), funcional (realizaram ecocardiograma com medida de pressão sistólica de ventrículo direito, ultrassonografia abdominal quando indicada e exames para excluir outras doenças) e laboratorial (entre eles, contagem de leucócitos, plaquetas e dosagem de BNP). A avaliação hemodinâmica foi realizada nos pacientes com HP. Para a análise da disfunção endotelial, foram coletados 40 mL de sangue de todos os indivíduos para a dosagem de Endotelina-1, Selectina E, VEGF, PDGF-AB e PDGF-BB. RESULTADOS: Observou-se que os grupos não se diferiram quanto a idade, houve um predomínio do sexo feminino e os grupos controle e ESQ apresentaram valores de PSVD menores do que os grupos com HP (controles: 23,4±4,6, ESQ: 29,5±8,5, HAPI: 79,8±26,4 e ESQ+HP: 75,2±15,3 mmHg). As medidas hemodinâmicas foram semelhantes em ambos os grupos com HAP. Quanto aos marcadores da função endotelial, o grupo controle apresentou valores séricos de PDGF-BB mais aumentados (8,9±4,8x 103 pg/mL, p<0,001) que os grupos HAPI, ESQ+HP, ESQ (3,7±2,1; 5,2±3 ; 2,4±1,7 x 103 pg/mL, respectivamente). O grupo HAPI apresentou valores mais elevados de Selectina E (61,5±24,2 x 103 pg/mL) que os grupos controle, ESQ+HP e ESQ (14,5±12,2; 23,9±15,3; 21,4±18 x 103 pg/mL, respectivamente, p=0,005). Os valores séricos de PDGF-AB do grupo controle foram mais elevados que no grupo ESQ (p=0,006). Não foram encontradas diferenças significantes nos valores séricos de Endotelina-1 entre os grupos (p=0,281). Em relação ao VEGF, os pacientes com HAPI apresentaram valores séricos similares ao grupo ESQ+HP e mais elevados que o grupo controle e ESQ (p=0,002). O ponto de corte da dosagem da selectina E (43.806 pg/mL) para diferenciar pacientes com HAPI dos pacientes com ESQ+HP apresentou uma sensibilidade de 91% e a especificidade de 89%. O PDGF-BB apresentou uma boa acurácia para distinguir o grupo controle dos demais, com uma sensibilidade de 77% e uma especificidade de 83%. Além disso, a Selectina E apresentou uma forte correlação com o níveis séricos de BNP (r=0,74, p=0,006). O número de leucócitos e de plaquetas foram diferentes entre os três grupos do estudo. Pacientes com HAPI tinham maior número de leucócitos e plaquetas quando comparados com esquistossomóticos. CONCLUSÕES: 1.Pacientes com HAPI apresentaram valores séricos mais elevados de Selectina E do que pacientes com esquistossomose e controles; 2.Pacientes portadores de esquistossomose com e sem HP apresentaram os mesmos valores séricos dos marcadores de disfunção endotelial / INTRODUCTION: There are several diseases that cause Pulmonary hypertension (PH), such as Idiopathic Pulmonary Arterial Hypertension and Schistosomiasis. The mechanisms that lead to PH are thought to be related to endothelial dysfunction. OBJECTIVES: To evaluate endothelial dysfunction, using plasma markers such as Endothelin-1(ET-1), E-Selectin, VEGF, PDGF-AB and -BB, in patients with idiopathic pulmonary arterial hypertension (IPAH) and schistosomiasis patients with or without PH; and to evaluate if schistosomiasis groups have endothelial dysfunction in the same degree. METHODOLOGY: Patients were divided in 4 different groups: Patients with IPAH (n=11), Patients with PH associated to Schistosomiasis (SchPH)(n=13), Patients with Schistosomiasis without PH (Sch)(n=13) and Controls(n=13). PAH patients were classified according to severity. All groups were submitted to echocardiography and right ventricule systolic pressure(RVSP) was measured. Abdominal ultrassonography was used to rule in or rule out schistosomiasis diagnosis. PH patients went through haemodynamics evaluation and all patients had laboratorial assessment (leucocytes and platelet count and BNP levels) Soluble adhesion molecules such as E-Selectin, VEGF, PDGF-AB, PDGF-BB e ET-1 were determined by ELISA. Leucocytes and platelet counts as well as BNP levels were also evaluated. Results: Subjects did not differ according to age and there was a higher proportion of female patients. Controls and Sch subjects had lower RVSP compared to PH groups (Sch: 23.4±4.6, controls: 29.5±8.5, IPAH: 79.8±26.4 and Sch+HP: 75.2±15.3 mmHg). Haemodynamics data did not differ in PH patients. In IPAH group, E-selectin was elevated (61.5±24,2x103pg/mL) compared to controls, Sch+HP and Sch (14.5±12.2; 23.9±15.3; 21.4±18 x103pg/mL, respectively, p=0,005). PDGF-BB was decreased in IPAH, Sch+HP, Sch (3.7±2.1; 5.2±3; 2.4±1.7x103pg/mL, respectively) compared to controls (8.9±4.8x 103 pg/mL, p<0.001). PDGF-AB was elevated in controls (25.6±8.6x103pg/mL) when compared to Sch (11.4±8.6 x103pg/mL)(p=0.006). There were no differences in ET-1 levels within groups. In relation to VEGF, IPAH group had higher levels compared to controls and Sch (96,6±68,2, 38,4±28, 37,±19,2 pg/mL, respectively) (p=0,002). Based on ROC curve, E-selectin cutoff value of 43.806 pg/mL showed a sensitivity of 91% and a specificity of 89% to distinguish IPAH patients from other groups and PDGF-BB had a good accuracy to differentiate controls with a sensitivity of 77% and a specificity of 83%. Furthermore, E-selectin had a strong correlation with BNP levels (r=0,74, p=0,006). The number of leucocytes and platelets were different within groups. IPAH patients had the highest, and Sch group had the lowest blood cells and platelets count. Conclusions: 1. IPAH patients had higher levels of serum E-selectin and VEGF and controls had higher levels of PDGF-BB and AB; 2. Schistosomiasis patients with or without PH had the same levels of endothelial dysfunction serum markers

Fundamento: O óxido nítrico inalatório (NOi) tem sido utilizado para controle e tratamento da hipertensão pulmonar (HP) durante ou imediatamente após cirurgias cardiotorácicas. Entretanto, seus efeitos comparados a outras medicações vasodilatadoras ainda são controversos. Objetivo: Revisar sistematicamente os efeitos do NOi comparado com outras medicações vasodilatadoras administrado durante ou imediatamente após cirurgias cardiotorácicas, sobre variáveis hemodinâmicas e oxigenação, em pacientes com HP. Métodos: Foi realizada uma busca sistemática nas bases de dados Cochrane CENTRAL, MEDLINE, Lilacs, PEDro e Embase, além de busca manual em referências de estudos publicados até maio de 2015. Foram incluídos ensaios clínicos randomizados (ECRs) que compararam NOi vs. outras medicações vasodilatadoras (inalatórias ou intravenosas) e que analisaram índice de oxigenação (relação PaO2/FiO2) e variáveis hemodinâmicas como pressão média da artéria pulmonar (PMAP), resistência vascular pulmonar (RVP), fração de ejeção do ventrículo direito (FEVD), saturação venosa mista de oxigênio (SvO2), índice cardíaco (IC), pressão venosa central (PVC), frequência cárdica (FC), pressão arterial média sistêmica (PAM), e resistência vascular sistêmica (RVS). Resultados: Foram identificados 2.561 artigos, totalizando seis ECRs incluídos. O uso do NOi comparado com outras medicações vasodilatadoras não promoveu alterações na relação PaO2/FiO2, PMAP, RVP, IC, FEVD, SvO2, PVC e RVS, entretanto houve redução na FC (-5,47 bpm; IC95%: -10,87 a -0,06) comparado com medicações inalatórias e aumento na PAM (9,30 mmHg; IC95%: 3,94 a 14,65; I2: 86%) comparado com medicações vasodilatadoras intravenosas. Conclusões: O uso do NOi não promoveu alterações na relação PaO2/FiO2 e nas variáveis hemodinâmicas comparado com outras medicações vasodilatadoras, exceto na FC onde houve redução e na PAM onde houve aumento, durante ou imediatamente após cirurgias cardiotorácicas em pacientes adultos com HP. / Introduction: The inhaled nitric oxide (INO) has been used for control and treatment of pulmonary hypertension (PH) during or immediately after cardiothoracic surgery. Although, the effects when compared to other vasodilator medications are still controversial. Objectives: The purpose of this study was to systematically review the effects of INO compared with other vasodilatory drugs administered during or immediately after cardiothoracic surgeries on hemodynamics and oxygenation variables in patients with PH. Methods: A systematic research was conducted in the databases Cochrane CENTRAL, MEDLINE, Lilacs, PEDro e Embase, in addition a manual search at references of published studies until May 2015. Randomised trials (RCTs) were included, comparing INO vs. other vasodilator medications (inhaled or intravenous), that analyzed the oxygenation index (ratio PaO2/FiO2) and hemodynamic variables: mean pulmonary artery pressure (MPAP), pulmonary vascular resistance (PVR), right ventricular ejection fraction (RVEF), mixed venous oxygen saturation (SvO2) , cardiac index (CI), central venous pressure (CVP), cardia rate (HR), mean systemic arterial pressure (MAP) and systemic vascular resistance (SVR). Results: We identified 2561 articles, being only six ECRs included. The use of NOi compared to other vasodilator medications did not change the ratio PaO2/FiO2, MPAP, PVR, CI, RVEF, SvO2, CVP e SVR, however there was a reduction in HR (-5,47 bpm; IC95%: -10,87 a -0,06) compared to inhaled medications and increased MAP (9,30 mmHg; IC95%: 3,94 a 14,65; I2: 86%) compared with intravenous vasodilator medications. Conclusion: The use of INO did not change ratio PaO2/FiO2 and hemodynamic variables, compared with other vasodilator medications, except HR where has been found a reduction, and MAP where has been found an increasing, during or immediately after thoracic cardiovascular surgery in adult patients with HP.

A debilitating illness, pulmonary arterial hypertension (PAH) arises from deleterious remodeling of pulmonary arterioles, leading to increased pulmonary artery pressure, a rise in pulmonary vascular resistance, right sided heart failure and death. The pathogenesis of the disease is incompletely understood; however, certain established pathological features have guided medical treatments to improve mortality rates. For instance, an imbalance of vasoconstrictor molecules, such as endothelin-1, to vasodilator compounds, such as nitric oxide, contributes to excessive pulmonary arterial constriction, and a propensity for pulmonary arterial smooth muscle and endothelial cell proliferation. Therapeutic strategies may aim to restore this imbalance with the use of endothelin receptor antagonists, prostacyclin analogs, and other vasodilating agents. Mutations in the BMPR2 gene, the most common genetic cause of PAH, leads to aberrant TGF-ß signaling, which promotes uncontrollable cell proliferation and pathological changes in pulmonary arterioles. Genetic studies have revealed PAH-associated mutations in several other genes within the TGF-ß signaling pathway. More recently, our research group discovered loss-of-function mutations in the KCNK3 gene encoding the KCNK3 two-pore domain potassium channel in patients with idiopathic and familial PAH. KCNK3 (also referred to as TASK-1, or K2P3.1) represents the first ion channelopathy as a cause of PAH. KCNK3 is expressed in human pulmonary artery smooth muscle and endothelial cells. Loss of KCNK3 channel currents leads to membrane depolarization and predisposes to deleterious pulmonary arterial remodeling. Chapter 1 of my thesis explores the impact of KCNK3 mutations on potassium channel function in cellular models of heterozygous conditions, as all patients with PAH-associated KCNK3 mutations in our study were heterozygous at the KCNK3 gene locus. Furthermore, we explored function of mutant and non-mutant KCNK3 channels in cultured human pulmonary artery smooth muscle cells to better define the electrophysiological consequence of KCNK3 dysfunction, and used a KCNK3-activating pharmacological agent, ONO-RS-082, to gauge the therapeutic potential of KCNK3 as a pharmacological target in PAH. Moreover, the study of KCNK3 channel activity when assembled with the closely related KCNK9 channel provided a platform for exploring the lung-specific phenotype in patients with heterozygous KCNK3 mutations, despite widespread tissue expression KCNK3 in the body. In Chapter 2 of my thesis work, the discovery of a second potassium channelopathy in PAH is characterized. Heterozygous mutations in the ABCC8 gene, encoding the sulfonylurea receptor 1 (SUR1) protein, were found in pediatric and adult patients with idiopathic and familial PAH. SUR1, a beta subunit of the ATP-sensitive potassium channel (KATP), assembles with the pore-forming Kir6.2 alpha subunit to form KATP, a channel sensitive to inhibition by intracellular ATP. At the plasma membrane, KATP inwardly rectifying potassium currents contribute to the resting potential, and may play a pathophysiological role in PAH via dysfunction in pulmonary artery smooth muscle and/or endothelial cells. In this chapter, eight ABCC8 mutations associated with PAH were functionally characterized, and pharmacological agents were employed to examine the therapeutic potential in targeting SUR1-containing KATP channels in PAH. Altogether, the research presented in this dissertation identifies and explores potassium channel dysfunction as a pathogenic mechanism in PAH, due to heterozygous genetic mutations in KCNK3 and ABCC8. Evidence of restoration of mutant KCNK3 and KATP channel function by pharmacological agents suggests that targeting potassium channels as a therapeutic strategy may alleviate the severe morbidity and mortality burden in patients with PAH.

Objetivo: Traduzir e adaptar para o português falado no Brasil a escala Dyspnoea-12. Fornecer dados de validação da escala para pacientes com DPOC e hipertensão pulmonar (HP). Métodos: A versão em inglês da escala Dyspnoea-12 sofreu processo clássico de tradução, até obtenção de versão definitiva em português denominada Dispneia-12-Pt. A escala Dispneia-12-Pt foi aplicada a 51 pacientes com DPOC (33 homens; idade: 66,4±8,1 anos; VEF1: 48,7±17,2%) e 15 com HP de diferentes etiologias (12 mulheres; idade: 45,8±12,7 anos; pressão sistólica da artéria pulmonar: 88±33,2 mmHg). Os voluntários responderam a escala de dispneia do Medical Research Council(MRC), o índice de dispneia basal (IDB), a escala hospitalar de ansiedade e depressão, questionário respiratório de Saint George (QRSG), avaliação funcional respiratória e teste da caminhada dos seis minutos (TC6min). Sessenta voluntários responderam a escala uma segunda vez, duas semanas após a primeira avaliação. Resultados: No grupo DPOC a escala Dispneia-12-Pt apresentou correlações significantes com as escalas MRC (r=0,4641; p=0,0006), IDB (r=0,515; p <0,0001), QRSG (r=0,8113; p<0,0001), ansiedade (r=0,4714; p=0,0005), depressão (0,4139; p=0,0025) e distância percorrida no TC6min (r=0,3293; p=0,0255). No grupo com HP a escala mostrou correlações significantes com as escalas MRC (r=0,5774; p=0,0242), QRSG (r=0,6907; p=0,0044), distância percorrida no TC6min (r=0,7193; p=0,0025) e difusão do monóxido de carbono (r=0,564; p=0,0447). O alfa de Cronbach para os voluntários analisados em um único grupo foi 0,927 e o coeficiente de correlação intraclasse 0,8456. Conclusões: A escala Dispneia-12-Pt apresenta propriedades biométricas aceitáveis e pode ser empregada em pacientes brasileiros com dispneia de diferentes etiologias. / Objective: To translate and to adapt for the Portuguese spoken in Brazil the scale Dyspnoea-12. To obtain validation data, regarding the use of this scale in patients with COPD and pulmonary hypertension (PH). Methods: The English version of the scale Dyspnoea-12 received a formal translation process and the final version was called Dispneia-12-Pt. The latter was applied to 51 COPD patients (33 men; age: 66.4±8.1 years; FEV1: 48.7±17.2 % pred) and 15 subjects with PH from different etiologies (12 women; age: 45.8±12.7 years; systolic pulmonary arterial pressure: 88±33.2 mmHg). The volunteers also answered the Medical Research Council dyspnea scale (MRC), the basal dyspnea index (DBI), the hospital scale of anxiety and depression, the Saint George Respiratory Questionnaire (SGRQ), respiratory functional evaluation and the six minute walk test (6 MWT). Sixty volunteers also answered the Dispneia-12-Pt scale about two weeks after the first evaluation. Results: In the COPD group the Dispneia-12-Br showed significant correlations with the scales MRC (r=0.4641; p=0.0006), BDI (0.515; p<0.0001), SGRQ (r=0.8113; p<0.0001), anxiety (r=0.4714; p=0.0005), depression (0.4139; p=0.0025) and walked distance in the 6 MWT (r=0.3293; p= 0.0255). In the HP group the scale showed significant correlations with the scales MRC (r=0.5774; p=0.0005), SGRQ (r=0.6907; p=0.0044), walked distance in the 6 MWT (0.7193; p=0.0025) and carbon dioxide diffusion capacity (r=0.564; p=0.0447). Cronbach´s alpha calculated for all volunteers evaluated as a whole was 0.927 while the intraclass correlation coefficient was 0.8456. Conclusions: The Dispneia-12-Pt exhibits acceptable biometric properties and may be used as a tool in Brazilian patients with dyspnea of different etiologies.

Rationale: Vascular remodeling and right-ventricular (RV) dysfunction are features of refractory pulmonary hypertension (PHT) in human neonates. These features are replicated in rats chronically exposed to hypoxia (13% O2), in which increased pulmonary vascular resistance (PVR) was acutely normalized by Y-27632, a Rho-kinase (ROCK) inhibitor, but not by inhaled nitric oxide. Objective: To examine the reversing effects of sustained ROCK inhibition on haemodynamic (RV dysfunction and increased PVR) and structural (RV hypertrophy and arterial wall remodeling) changes of chronic hypoxic PHT. Methods: Rat pups were exposed to air or hypoxia from birth for up to 21 days and received Y-27632 (15 mg/kg/b.i.d.) or vehicle from day 14. Results: Y-27632 normalised RV dysfunction and reversed remodeling secondary to chronic hypoxia. These changes were accompanied by increased apoptosis of smooth muscle and attenuated endothelin-1 expression in pulmonary arteries. Conclusion: ROCK inhibitors hold promise as a rescue therapy for refractory PHT in neonates.