Exercise training contributes to H2O2/VEGF signaling in the lung of rats with monocrotaline-induced pulmonary hypertension

Sulforaphane Improves Redox Homeostasis and Right Ventricular Contractility in a Model of Pulmonary Hypertension

ABSTRACT

Pulmonary arterial hypertension (PAH) is characterized by increased pulmonary vascular resistance (PVR), imposing overload on the right ventricle (RV) and imbalance of the redox state. Our study investigated the influence of treatment with sulforaphane (SFN), found in cruciferous vegetables, on RV remodeling and redox homeostasis in monocrotaline (MCT)-induced PAH. Male Wistar rats were separated into 4 groups: control (CTR); CTR + SFN; MCT; and MCT + SFN. PAH induction was implemented by a single dose of MCT (60 mg/kg intraperitoneally). Treatment with SFN (2.5 mg/kg/day intraperitoneally) started on the seventh day after the MCT injection and persisted for 2 weeks. After 21 days of PAH induction, echocardiographic, hemodynamic, and oxidative stress evaluation was performed. The MCT group showed an increase in RV hypertrophy, RV systolic area, RV systolic, mean pulmonary artery pressure, and PVR and exhibited a decrease in the RV outflow tract acceleration time/ejection time ratio, RV fractional shortening, and tricuspid annular plane systolic excursion compared to CTR ( P < 0.05). SFN-treated PAH attenuated detrimental changes in tricuspid annular plane systolic excursion, mean pulmonary artery pressure, and PVR parameters. Catalase levels and the glutathione/Glutathione disulfide (GSSG) ratio were diminished in the MCT group compared to CTR ( P < 0.05). SFN increased catalase levels and normalized the glutathione/GSSG ratio to control levels ( P < 0.05). Data express the benefit of SFN treatment on the cardiac function of rats with PAH associated with the cellular redox state.

Combined physical training protects the left ventricle from structural and functional damages in experimental pulmonary arterial hypertension

BACKGROUND

Under the adverse remodeling of the right ventricle and interventricular septum in pulmonary arterial hypertension (PAH) the left ventricle (LV) dynamics is impaired. Despite the benefits of combined aerobic and resistance physical trainings to individuals with PAH, its impact on the LV is not fully understood.

OBJECTIVE

To test whether moderate-intensity combined physical training performed during the development of PAH induced by MCT in rats is beneficial to the LV's structure and function.

METHODS

Male Wistar rats were divided into two groups: Sedentary Hypertensive Survival (SHS, n = 7); and Exercise Hypertensive Survival (EHS, n = 7) to test survival. To investigate the effects of combined physical training, another group of rats were divided into three groups: Sedentary Control (SC, n = 7); Sedentary Hypertensive (SH, n = 7); and Exercise Hypertensive (EH, n = 7). PAH was induced through an intraperitoneal injection of MCT (60 mg/kg). Echocardiographic evaluations were conducted on the 22nd day after MCT administration. Animals in the EHS and EH groups participated in a combined physical training program, alternating aerobic (treadmill running: 50 min, 60% maximum running speed) and resistance (ladder climbing: 15 climbs with 1 min interval, 60% maximum carrying load) exercises, one session/day, 5 days/week for approximately 4 weeks.

RESULTS

The physical training increased survival and tolerance to aerobic (i.e., maximum running speed) and resistance (i.e., maximum carrying load) exertions and prevented reductions in ejection fraction and fractional shortening. In addition, the physical training mitigated oxidative stress (i.e., CAT, SOD and MDA) and inhibited adverse LV remodeling (i.e., Collagen, extracellular matrix, and cell dimensions). Moreover, the physical training preserved the amplitude and velocity of contraction and hindered the reductions in the amplitude and velocity of the intracellular Ca2+ transient in LV single myocytes.

CONCLUSION

Moderate-intensity combined physical training performed during the development of MCT-induced PAH in rats protects their LV from damages to its structure and function and hence increases their tolerance to physical exertion and prolongs their survival.

Atorvastatin rescues pulmonary artery hypertension by inhibiting the AKT/ERK-dependent PDGF-BB/HIF-1α axis

BACKGROUND

The aim of this study is to explore the role of atorvastatin in rescuing pulmonary artery hypertension (PAH) by inhibiting the AKT/ERK-dependent PDGF-BB/HIF-1α axis.

METHODS

PAH model in rats was established by MCT induction, followed by Atorvastatin intervention. Pulmonary hemodynamic measurement and pulmonary morphological evaluation in rats were conducted. Human pulmonary artery smooth muscle cells (hPASMCs) were subjected to hypoxic exposure or PDGF-BB treatment, followed by atorvastatin induction. Relative levels of HIF-1α, p-ERK and p-Akt were detected. Viability and apoptosis were respectively determined by cell counting kit-8 (CCK-8) assay and flow cytometry.

RESULTS

Atorvastatin protected PAH-induced increases in RVSP and Fulton's index in rats. Meanwhile, it inhibited vascular remodeling following PAH by downregulating HIF-1α and PDGF-BB. Hypoxia or PDGF-BB treatment in hPASMCs resulted in upregulation of p-ERK and p-Akt, and viability increase, which were partially abolished by Atorvastatin intervention. In addition, atorvastatin triggered apoptosis in hypoxia or PDGF-BB-induced hPASMCs.

CONCLUSIONS

Atorvastatin inhibits the activation of HIF-1α and proliferative ability, and triggers apoptosis in hPASMCs exposed to hypoxia or PDGF-BB treatment through inactivating the AKT/ERK pathway.

Effects of voluntary running on the skeletal muscle of rats with pulmonary artery hypertension

The effects of voluntary running on the skeletal muscle of rats with pulmonary arterial hypertension (PAH) were tested in the present study. PAH was induced in rats by a single injection of monocrotaline (MCT, 60 mg/kg). Rats in the sedentary hypertension (HS) group had their tolerance to physical exertion reduced throughout the experiment, while those in the sedentary control (SC), exercise control (EC), exercise hypertension (EH) and median exercise (EM) groups maintained or increased. Despite that, the muscular citrate synthase activity was not different between groups. The survival time was higher in the EH (32 days) than in the SH (28 days) (p = 0.0032). SH and EH groups showed a lower percentage of muscle fiber and a higher percentage of extracellular matrix compared to control groups (p < 0.0001). However, the EM and EH groups presented higher percentage of muscle fiber and lower percentage of extracellular matrix than SH group (p < 0.0001). Regarding muscular gene expression, the SH and EM groups showed a lower expression of PGC1-α (p = 0.0024) and a higher expression of VEGF (p = 0.0033) compared to SC, while PGC1-α was elevated in the EH. No difference between groups was found for the carbonylated protein levels (p > 0.05), while the TNF-α/IL-10 ratio was augmented in the EH (p = 0.0277). In conclusion, voluntary running augments the proportion of fiber and affects the gene expression of inflammatory and mitochondrial biogenesis' markers in the skeletal muscle of rats with MCT-induced PAH, which benefits their survival and tolerance to physical effort.

Effects of Exercise Training on Circulating Biomarkers of Endothelial Function in Pulmonary Arterial Hypertension

INTRODUCTION

In stable patients with pulmonary arterial hypertension (PAH), pulmonary rehabilitation (PR) is an effective, safe and cost-effective non-pharmacological treatment. However, the effects of PR on vascular function have been poorly explored. This study aimed to compare the amounts of circulating progenitor cells (PCs) and endothelial microvesicles (EMVs) in patients with PAH before and after 8 weeks of endurance exercise training as markers of vascular competence.

METHODS

A prospective study of 10 consecutive patients with PAH that successfully finished a PR program (8 weeks) was carried out before and after this intervention. Levels of circulating PCs defined as CD34+CD45low progenitor cells and levels of EMVs (CD31+ CD42b-) were measured by flow cytometry. The ratio of PCs to EMVs was taken as a measure of the balance between endothelial damage and repair capacity.

RESULTS

All patients showed training-induced increases in endurance time (mean change 287 s). After PR, the number of PCs (CD34+CD45low/total lymphocytes) was increased (p < 0.05). In contrast, after training, the level of EMVs (CD31+ CD42b-/total EMVs) was reduced. The ratio of PCs to EMVs was significantly higher after training (p < 0.05).

CONCLUSION

Our study shows, for the first time, that endurance exercise training in patients with stable PAH has a positive effect, promoting potential mechanisms of damage/repair in favor of repair. This effect could contribute to a positive hemodynamic and clinical response.

The role of O3 exposure and physical activity status on redox state, inflammation, and pulmonary toxicity of young men: A cross-sectional study

The exposure to traffic-related air pollutants, such as NO₂ and O₃, are associated with detrimental health effects, becoming one of the greatest public health issues worldwide. Exercising in polluted environments could result in harmful outcomes for health and may blunt the physiological adaptations of exercise training. This study aimed to investigate the influence of physical activity and O₃ exposure on redox status, an inflammatory marker, response to stress, and pulmonary toxicity of healthy young individuals. We performed a cross-sectional study with 100 individuals that, based on their exposure to O₃ and physical fitness (PF) level, were distributed in four groups: Low PF + Low O₃; Low PF + High O₃; High PF + Low O₃; High PF + High O₃. We evaluated personal exposure to NO₂ and O_3, physical activity level, variables of oxidative stress (SOD, ROS, CAT, GSH, TBARS), pulmonary toxicity (CC16), and inflammatory mediators (IL-1β, IL-4, IL-6, IL-10, TNF-α, HSP70). Spearman correlation test to check the association among the variables was used and to compare groups we used one-way ANOVA followed by Bonferroni's post hoc and Kruskal Wallis test followed by Dunn's post hoc. O₃ levels correlated with physical activity (r = 0.25; p = 0.01) but not with age or markers of body composition (p > 0.05). The individuals with high physical fitness that were less exposed to O₃ presented higher CAT activity (p < 0.001), lower TBARS (p < 0.01) and IL-1β concentrations (p < 0.01), higher IL-6 (p < 0.05) and IL-10 concentrations (p < 0.05), lower IL-6:1L-10 ratio (p < 0.05), lower CC16 levels (p < 0.05), and higher HSP70 concentration (p < 0.05). Physical activity could result in higher exposure to O₃ that could partially blunt some exercise adaptations, while high physical fitness improved the antioxidant defense system, systemic inflammatory mediators, and pulmonary toxicity.

Serum metabolomics using ultra-high performance liquid chromatography-Q-Exactive tandem mass spectrometry reveals the mechanism of action of exercise training on chronic obstructive pulmonary disease rats

Exercise training is the cornerstone component of pulmonary rehabilitation, which results in symptom-reducing, psychosocial, and health economic benefits for chronic obstructive pulmonary disease (COPD) patients. However, the potential mechanisms of its action are poorly understood. This study conducted serum metabolomics using ultra-high performance liquid chromatography-Q-Exactive tandem mass spectrometry to determine the metabolic changes in COPD rats, and the effects of exercise training on improvement in COPD were further investigated. Twelve differential metabolites-which are primarily related to tryptophan metabolism, sphingolipid metabolism, glycerophospholipid metabolism, riboflavin metabolism, pantothenate and CoA biosynthesis, and lysine degradation-were identified in relation to COPD. After the intervention of exercise training, the levels of most metabolites were restored, and the changes in five metabolites were statistically significant, which suggested that exercise training provided effective protection against COPD and might play its role by rebalancing disordered metabolism pathways. This work enhanced our comprehension of the protective mechanism of exercise training on COPD.

Exercise training decreases oxidative stress in skeletal muscle of rats with pulmonary arterial hypertension

The effects of exercise training on oxidative stress in gastrocnemius of rats with pulmonary hypertension were studied. Four groups were established: sedentary control (SC), sedentary monocrotaline (SM), trained control (TC), trained monocrotaline (TM). Exercise was applied for 4 weeks, 5 days/week, 50-60 min/session, at 60% of VO₂ max. Right ventricular (RV) pressures were measured, heart and gastrocnemius were removed for morphometric/biochemical analysis. Lipid peroxidation (LPO), H₂O₂, GSH/GSSG, and activity/expression of antioxidant enzymes were evaluated. Increased RV hypertrophy, systolic and end-diastolic pressures (RVEDP) were observed in SM animals, and the RVEDP was decreased in TM vs. SM. H₂O₂, SOD-1, and LPO were higher in the SM group than in SC. In TM, H₂O₂ was further increased when compared to SM, with a rise in antioxidant defences and a decrease in LPO. GSH/GSSG was higher only in the TC group. Exercise induced an efficient antioxidant adaptation, preventing oxidative damage to lipids.

O Treinamento Físico Resistido Atenua as Disfunções Ventriculares Esquerdas em Modelo de Hipertensão Arterial Pulmonar

Fundamento

A hipertrofia e a dilatação do ventrículo direito observadas na hipertensão arterial pulmonar (HAP) prejudicam a dinâmica do ventrículo esquerdo (VE) achatando o septo interventricular.

Objetivo

Investigar se o treinamento físico resistido (TFR) de intensidade baixa a moderada é benéfico para funções contráteis do VE e de cardiomiócitos em ratos durante o desenvolvimento de HAP induzida por monocrotalina (MCT).

Métodos

Foram usados ratos Wistar machos (Peso corporal: ~ 200 g). Para avaliar o tempo até o possível surgimento de insuficiência cardíaca (ou seja, ponto de desfecho), os ratos foram divididos em dois grupos, hipertensão com sedentarismo até a insuficiência (HSI, n=6) e hipertensão com treinamento até a insuficiência (HTI, n=6). Para testar os efeitos do TFR, os ratos foram divididos entre grupos de controle sedentários (CS, n=7), hipertensão com sedentarismo (HS, n=7) e hipertensão com treinamento (HT, n=7). A HAP foi induzida por duas injeções de MCT (20 mg/kg, com um intervalo de 7 dias). Os grupos com treinamento foram submetidos a um protocolo de TFR (subir escadas; 55-65% da máxima carga carregada), 5 dias por semana. A significância estatística foi definida em p <0,05.

Resultados

O TFR prolongou o ponto de desfecho (~25%), melhorou a tolerância ao esforço físico (~55%) e atenuou as disfunções de contratilidade de VE e de cardiomiócitos promovidas pela MCT preservando a fração de ejeção e o encurtamento fracional, a amplitude do encurtamento, e as velocidades de contração e relaxamento nos cardiomiócitos. O TFR também preveniu os aumentos de fibrose e colágeno tipo I no ventrículo esquerdo causados pela MCT, além de manter as dimensões de miócitos e colágeno tipo III reduzidas por MCT.

Conclusão

O TFR de intensidade baixa a moderada é benéfico para funções contráteis de VE e cardiomiócitos em ratos durante o desenvolvimento de HAP induzida por MCT.

Preventive training does not interfere with mRNA-encoding myosin and collagen expression during pulmonary arterial hypertension

To gain insight on the impact of preventive exercise during pulmonary arterial hypertension (PAH), we evaluated the gene expression of myosins and gene-encoding proteins associated with the extracellular matrix remodeling of right hypertrophied ventricles. We used 32 male Wistar rats, separated in four groups: Sedentary Control (S, n = 8); Control with Training (T, n = 8); Sedentary with Pulmonary Arterial Hypertension (SPAH, n = 8); and Pulmonary Arterial Hypertension with Training (TPAH, n = 8). All rats underwent a two-week adaptation period; T and TPAH group rats then proceeded to an eight-week training period on a treadmill. At the beginning of the 11th week, S and T groups received an intraperitoneal injection of saline, and SPAH and TPAH groups received an injection of monocrotaline (60 mg/kg). Rats in the T and TPAH groups then continued with the training protocol until the 13th week. We assessed exercise capacity, echocardiography analysis, Fulton's index, cross-sectional areas of cardiomyocytes, collagen content and types, and fractal dimension (FD). Transcript abundance of myosins and extracellular matrix genes were estimated through reverse transcription-quantitative PCR (RT-qPCR). When compared to the SPAH group, the TPAH group showed increases in functional capacity and pulmonary artery acceleration time/pulmonary ejection time ratio and decreases in Fulton's index and cross-sectional areas of myocyte cells. However, preventive exercise did not induce alterations in col1a1 and myh7 gene expression. Our findings demonstrate that preventive exercise improved functional capacity, reduced cardiac hypertrophy, and attenuated PH development without interfering in mRNA-encoding myosin and collagen expression during PAH.

Continuous Aerobic Exercise Prevents Detrimental Remodeling and Right Heart Myocyte Contraction and Calcium Cycling Dysfunction in Pulmonary Artery Hypertension

ABSTRACT

Pulmonary artery hypertension (PAH) imposes right heart and lung detrimental remodeling which impairs cardiac contractility, physical effort tolerance, and survival. The effects of an early moderate-intensity continuous aerobic exercise training on the right ventricle and lung structure, and on contractility and the calcium (Ca2+) transient in isolated myocytes from rats with severe PAH induced by monocrotaline were analyzed. Rats were divided into control sedentary (CS), control exercise (CE), monocrotaline sedentary (MS), and monocrotaline exercise (ME) groups. Animals from control exercise and ME groups underwent a moderate-intensity aerobic exercise on a treadmill (60 min/d; 60% intensity) for 32 days, after a monocrotaline (60 mg/kg body weight i.p.) or saline injection. The pulmonary artery resistance was higher in MS than in control sedentary (1.36-fold) and was reduced by 39.39% in ME compared with MS. Compared with MS, the ME group presented reduced alveolus (17%) and blood vessel (46%) wall, fibrosis (25.37%) and type I collagen content (55.78%), and increased alveolus (52.96%) and blood vessel (146.97%) lumen. In the right ventricle, the ME group exhibited diminished hypertrophy index (25.53%) and type I collagen content (40.42%) and improved myocyte contraction [ie, reduced times to peak (29.27%) and to 50% relax (13.79%)] and intracellular Ca2+ transient [ie, decreased times to peak (16.06%) and to 50% decay (7.41%)] compared with MS. Thus, early moderate-intensity continuous aerobic exercise prevents detrimental remodeling in the right heart and lung increases in the pulmonary artery resistance and dysfunction in single myocyte contraction and Ca2+ cycling in this model.

Effects of exercise rehabilitation training on patients with pulmonary hypertension

Pulmonary hypertension (PH) comprises a group of pathophysiological syndromes characterized by elevated pulmonary artery pressure and pulmonary vascular resistance, which lead to right ventricular overload, and even right heart failure. PH has a poor prognosis and severely leads to a decline in quality of life. Historically, patients with PH were advised to limit their physical activity. However, an increasing number of studies have reported the safety and efficacy of exercise rehabilitation training in PH. This review briefly examined and summarized the effects of exercise rehabilitation training on PH patients reported in the recent literature. The findings of the reviewed studies indicate that exercise rehabilitation training in PH patients has beneficial effects in terms of exercise capacity and quality of life, vascular and right ventricle remodelling, inflammatory response, muscular function and oxidative stress. However, the underlying mechanisms and appropriate exercise strategies (e.g. the duration and intensity of exercise) still need to be explored. In conclusion, exercise rehabilitation training of the appropriate intensity and frequency can improve the prognosis and quality of life of PH patients. The training should be monitored by professional staff and be provided as an adjunct to pharmacological treatment. Larger clinical trials are required to confirm the safety and efficacy of exercise rehabilitation training in PH.

Effects of Different Types of Exercise Training on Pulmonary Arterial Hypertension: A Systematic Review

Pulmonary arterial hypertension (PAH) represents a chronic progressive disease characterized by high blood pressure in the pulmonary arteries leading to right heart failure. The disease has been a focus of medical research for many years due to its worse prognosis and limited treatment options. The aim of this study was to systematically assess the effects of different types of exercise interventions on PAH. Electronic databases were searched until July 2019. MEDLINE database was used as the predominant source for this paper. Studies with regards to chronic physical activity in adult PAH patients are compared on retrieving evidence on cellular, physiological, and psychological alterations in the PAH setting. Twenty human studies and 12 rat trials were identified. Amongst all studies, a total of 628 human subjects and 614 rats were examined. Regular physical activity affects the production of nitric oxygen and attenuates right ventricular hypertrophy. A combination of aerobic, anaerobic, and respiratory muscle training induces the strongest improvement in functional capacity indicated by an increase of 6 MWD and VO₂peak. In human studies, an increase of quality of life was found. Exercise training has an overall positive effect on the physiological and psychological components of PAH. Consequently, PAH patients should be encouraged to take part in regular exercise training programs.

Oxidative Stress and Its Implications in the Right Ventricular Remodeling Secondary to Pulmonary Hypertension

Pulmonary hypertension (PH) is a pulmonary vascular disease characterized by increased pulmonary artery pressures. Long standing pulmonary arterial pressure overload leads to right ventricular (RV) hypertrophy, RV failure, and death. RV failure is a major determinant of survival in PH. Oxidative stress has been associated with the development of RV failure secondary to PH. Here we summarize the structural and functional changes in the RV in response to sustained pulmonary arterial pressure overload. Furthermore, we review the pre-clinical and clinical studies highlighting the association of oxidative stress with pulmonary vasculature and RV remodeling in chronic PH. Targeting oxidative stress promises to be an effective therapeutic strategy for the treatment of RV failure.

Caffeic Acid Phenethyl Ester Rescues Pulmonary Arterial Hypertension through the Inhibition of AKT/ERK-Dependent PDGF/HIF-1α In Vitro and In Vivo

Pulmonary arterial hypertension (PAH) is characterized by pulmonary arterial proliferation and remodeling, resulting in a specific increase in right ventricle systolic pressure (RVSP) and, ultimately right ventricular failure. Recent studies have demonstrated that caffeic acid phenethyl ester (CAPE) exerts a protective role in NF-κB-mediated inflammatory diseases. However, the effect of CAPE on PAH remains to be elucidated. In this study, monocrotaline (MCT) was used to establish PAH in rats. Two weeks after the induction of PAH by MCT, CAPE was administrated by intraperitoneal injection once a day for two weeks. Pulmonary hemodynamic measurements and pulmonary artery morphological assessments were examined. Our results showed that administration of CAPE significantly suppressed MCT-induced vascular remodeling by decreasing the HIF-1α expression and PDGF-BB production, and improved in vivo RV systolic performance in rats. Furthermore, CAPE inhibits hypoxia- and PDGF-BB-induced HIF-1α expression by decreasing the activation of the AKT/ERK pathway, which results in the inhibition of human pulmonary artery smooth muscle cells (hPASMCs) proliferation and prevention of cells resistant to apoptosis. Overall, our data suggest that HIF-1α is regarded as an alternative target for CAPE in addition to NF-κB, and may represent a promising therapeutic agent for the treatment of PAH diseases.

Novel insights into the molecular mechanisms underlying the beneficial effects of exercise training on pulmonary arterial hypertension

BACKGROUND

Recent animal and clinical studies report that exercise training exerts positive influences in pulmonary arterial hypertension (PAH); however, the underlying mechanisms are largely unknown. To give insight into the molecular mechanisms of the improvement effects, we performed gene expression analysis.

METHODS

Three Gene Expression Omnibus (GEO) datasets were analyzed, including peripheral blood mononuclear (PBMC) gene expression profiles of exercise training in men and patients with PAH. Differentially expressed genes (DEGs) in each dataset were identified, and then, the common DEGs positively regulated by PAH and negatively regulated by exercise training, or the opposite, were further identified. Subsequently, biological processes and pathways were analyzed.

RESULTS

A total of 7229 DEGs with logFC>0.3 and P<0.05 were identified in exercise, whereas 749 and 2207 DEGs were identified in PAH from the two datasets. After overlapping the whole DEGs from all three datasets, total 16 common DEGs were identified, including BCLAF1, SATB1 and ZFP36L2. Seven of them were up-regulated in exercise training and down-regulated in PAH, and the others were opposite. In addition, these common DEGs were mainly enriched in negative regulation of cellular process, negative regulation of biological process and negative regulation of cellular macromolecule biosynthetic process.

CONCLUSIONS

Some genes have been implicated in the improvement of pulmonary vascular remodeling and PAH. These findings could not only improve the knowledge about the molecular mechanisms underlying the beneficial effects of exercise training on PAH, but also provide clues for further clinical and animal studies.

Exercise training in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is characterized by a continuous increase in pre-capillary pulmonary vascular resistance (PVR) with a progressive reduction of cardiac output (CO). Similar to what occurs in left heart failure (HF), this represents the initial phase of a syndrome characterized by the progressive development of dyspnea and fatigue with increasing deterioration of exercise tolerance. Although the therapies introduced in the last two decades have determined a significant improvement of the clinical conditions of PAH patients, they have a little impact on exercise capacity and prognosis. However, as previously demonstrated for HF, recent pilot studies have reported that physical and respiratory rehabilitation may have a specific role in the management of PAH. Despite potential risks, so far all studies agree that exercise training (ET) improves exercise capacity, quality of life (QoL), muscle function and pulmonary circulation. We will review the pathophysiological mechanisms underlying the functional incompetence of PAH patients, the effects of ET on clinical and functional parameters, the selection criteria for inclusion of patients in a training program, the suggested monitoring of beneficial effects or possible side effects induced by ET. Finally, we discuss of the possible exercise induced amelioration of prognosis in PAH.

Redox regulation of gasotransmission in the vascular system: A focus on angiogenesis

Reactive oxygen species have emerged as key participants in a broad range of physiological and pathophysiological processes, not least within the vascular system. Diverse cellular functions which have been attributed to some of these pro-oxidants within the vasculature include the regulation of blood pressure, neovascularisation and vascular inflammation. We here highlight the emerging roles of the enzymatically-generated reaction oxygen species, O₂^- and H₂O₂, in the regulation of the functions of the gaseous signalling molecules: nitric oxide (NO), carbon monoxide (CO), and hydrogen sulphide (H₂S). These gasotransmitters are produced on demand from distinct enzymatic sources and in recent years it has become apparent that they are capable of mediating a number of homeostatic processes within the cardiovascular system including enhanced vasodilation, angiogenesis, wound healing and improved cardiac function following myocardial infarction. In common with O₂^- and/or H₂O₂ they signal by altering the functions of target proteins, either by the covalent modification of thiol groups or by direct binding to metal centres within metalloproteins, most notably haem proteins. The regulation of the enzymes which generate NO, CO and H₂S have been shown to be influenced at both the transcriptional and post-translational levels by redox-dependent mechanisms, while the activity and bioavailability of the gasotransmitters themselves are also subject to oxidative modification. Within vascular cells, the family of nicotinamide adenine dinucleotide phosphate oxidases (NAPDH oxidases/Noxs) have emerged as functionally significant sources of regulated O₂^- and H₂O₂ production and accordingly, direct associations between Nox-generated oxidants and the functions of specific gasotransmitters are beginning to be identified. This review focuses on the current knowledge of the redox-dependent mechanisms which regulate the generation and activity of these gases, with particular reference to their roles in angiogenesis.

Aerobic exercise-related attenuation of arterial pulmonary hypertension: A right arrow targets the disease?

Characterized by progressive elevation of mean pulmonary artery pressure and pulmonary vascular resistance, pulmonary arterial hypertension (PAH) is an important health problem that contributes to right heart failure. Pulmonary arterial remodeling and constriction are two prominent features of PAH. It is a traditional view that increasing pulmonary blood flow and pressure, aerobic exercise does more harm than good to the pulmonary vasculature in PAH. However, recent studies have documented a potential benefit of low-intensity aerobic exercise for PAH patients. Here the current mini-review outlines the evidence and challenges for this additional tool in our armamentarium to combat this ominous disease.