Pulmonary arterial hypertension

RNA binding proteins: Mechanistic considerations and perspectives in controlling cardiovascular diseases

Cardiovascular diseases (CVDs) are becoming serious disease that endangering human health due to the increasing morbidity and mortality, and many molecular targets are involved in this complex pathologic process. Recently, RNA-binding proteins (RBPs) have received potential attention as a promising targets for preventing CVDs, including myocardial hypertrophy, dilated cardiomyopathy (DCM), myocardial fibrosis, and pulmonary hypertension (PH). As important regulators of RNA metabolism, RBPs play important roles in all steps of the gene expression cascade,and affect the occurrence and development of various diseases. In this review, we discuss the regulatory role of RBPs on various CVDs at the post transcriptional modification level based on current research. We also highlight the existing and potential RNA-based therapeutics that could impact future CVD treatments.

Phase 1 Studies to Assess Inhaled Seralutinib as a Perpetrator or a Victim of Drug-Drug Interactions in Healthy Participants

Seralutinib, an inhaled, small-molecule tyrosine kinase inhibitor in clinical development for the treatment of pulmonary arterial hypertension (PAH), was evaluated for its potential as a perpetrator or victim of a metabolic and transporter-based drug-drug interactions in 2 phase 1 studies. In study 1, 24 participants received a cocktail of probe substrates: caffeine (CYP1A2), montelukast (CYP2C8), flurbiprofen (CYP2C9), midazolam (CYP3A), and pravastatin (OATP1B1/1B3), plus digoxin (P-gp) with or without seralutinib. In study 2, 19 participants received seralutinib with/without itraconazole, a strong CYP3A inhibitor, or fosaprepitant, a weak CYP3A inhibitor. Geometric least-squares mean ratios and 90% confidence intervals for maximum observed concentration (Cmax) and area under the plasma concentration-time curve (AUC) were obtained. Safety was monitored throughout the studies. All adverse events were mild or moderate in severity. Seralutinib coadministration increased AUC for midazolam 3.03-fold and caffeine 1.32-fold. The coadministration increased digoxin Cmax 1.28-fold. Seralutinib did not meaningfully alter Cmax and AUC for montelukast, flurbiprofen, or pravastatin. Fosaprepitant and itraconazole increased seralutinib AUC 1.08- and 1.84-fold, respectively. Seralutinib is a moderate CYP3A inhibitor and a weak CYP1A2 inhibitor; it slightly inhibits P-gp. Seralutinib exposure is minimally affected by a weak CYP3A inhibitor but is substantially increased by a strong CYP3A inhibitor.

Assessing the causality between pulmonary arterial hypertension and cancer: insights from Mendelian randomization

BACKGROUND

Previous clinical studies have suggested an increased risk of tumor development in patients with pulmonary arterial hypertension (PAH). However, it remains unclear whether there is a causal relationship between PAH and tumor occurrence. This study investigates the causal link between PAH and cancer from a genetic perspective using Mendelian randomization (MR).

METHOD

Genome-wide association study (GWAS) summary data for PAH and various common cancer types were obtained from the GWAS Catalog. Single nucleotide polymorphisms (SNPs) significantly associated with PAH at the genome-wide significance threshold (P < 1 × 10-6) were selected as instrumental variables (IVs). Inverse-variance weighted (IVW) was used as the primary method for MR analysis, with sensitivity analyses including tests for heterogeneity and horizontal pleiotropy.

RESULTS

The results from the IVW analysis indicate that genetically proxied PAH is associated with an increased risk of liver cancer [odd ratio (OR) 1.11, 95% confidence interval (CI) 1.01-1.22, P = 0.025), while showing no significant causal relationship with other common types of tumors (thyroid cancer: OR 0.95, 95% CI 0.86-1.06, P = 0.360; lung cancer: OR 0.95, 95% CI 0.90-1.01, P = 0.129; gastric cancer: OR 0.97, 95% CI 0.93-1.02, P = 0.243; colorectal cancer: OR 1.01, 95% CI 0.98-1.05, P = 0.412). Except for the MR analysis examining the causal effect of PAH on lung cancer (P = 0.049), the remaining MR analyses displayed no significant heterogeneity (P > 0.05). Additionally, the MR-Egger intercept test did not find evidence of horizontal pleiotropy (P > 0.05).

CONCLUSION

This study highlights that PAH may serve as a potential risk factor for this liver cancer. Future research should aim to elucidate the biological mechanisms at play and explore the potential for early interventions that could mitigate cancer risk in this vulnerable population.

Pulmonary Arterial Hypertension Affects Sperm Quality and Epididymis Function in Sedentary and Exercised Wistar Rats

Pulmonary arterial hypertension (PAH) is a disease that affects millions of people worldwide. Besides the effects on the lungs and heart, PAH can affect other organs, including the liver, kidneys, brain, glands, and testis. This study aimed to evaluate the impact of PAH and physical resistance training (RT), a complementary treatment for hypertension, on epididymis morphology and function and sperm parameters. Wistar rats were divided into four experimental groups (n = 8/ group): sedentary control, sedentary PAH, RT control, and RT + PAH. PAH was induced using monocrotaline injections on Day 1 and 7 of the experiment. Sixteen rats from RT groups underwent RT training for 30 days, while rats from sedentary groups did not exercise. The epididymis was processed and analyzed using microscopic, biochemical, and functional approaches. Sperm were harvested from the cauda epididymis and evaluated for morphology and motility. Our results showed that PAH compromised the epididymis antioxidant defense system and reduced NO levels, leading to an imbalance in the organ's mineral content. These alterations affected the epididymis morphology and reduced the sperm transit time in the proximal epididymis, resulting in an increase in abnormal sperm morphology in the cauda region. Unfortunately, RT was not a good therapy against the PAH effect on the epididymis. PAH negatively affected epididymis functions with consequences to male gametes. Dysfunctions in the post-testicular environment may lead to male infertility due to the disturbance of spermatozoa fecundity.

Molecular Hydrogen Therapy in Sjögren's Syndrome With Pulmonary Arterial Hypertension and Right-sided Heart Failure: A Case Report of Improved Immune Markers Including Treg, B Cells and Plasma Cell

BACKGROUND/AIM

Connective tissue disease-associated pulmonary arterial hypertension (CTD-PAH) is a severe complication characterized by elevated pulmonary artery pressure, which can lead to right heart failure and death, if untreated. Standard treatments often fail to adequately manage symptoms, highlighting the need for novel therapeutic approaches. This study investigated the efficacy of molecular hydrogen (H2) therapy in a patient with CTD-PAH.

CASE REPORT

We present the case of a 56-year-old female with CTD-PAH, diagnosed in 2013 with Sjogren's syndrome complicated by interstitial lung disease (ILD) and PAH. Despite treatment with sildenafil, bosentan, macitentan, iloprost, and corticosteroids, her condition deteriorated, resulting in severe dyspnea and cardiogenic shock in 2020. In May 2023, molecular hydrogen therapy was initiated as an adjuvant treatment. The patient received daily hydrogen capsules, which led to increased CD127+ Treg cells, reduced anti-Ro antibodies, and decreased B cell subsets. Her clinical symptoms stabilized without adverse effects.

CONCLUSION

This case highlights the potential benefits of molecular hydrogen therapy in CTD-PAH. H2 therapy exhibiting anti-inflammatory and immunomodulatory effects, leading to improved immune cell profiles and stabilizing clinical symptoms in a patient unresponsive to conventional treatments. Further research is needed to elucidate the mechanisms of H2 therapy and validate its efficacy in larger cohorts. Molecular hydrogen therapy shows promise as a safe adjunctive treatment for CTD-PAH, offering a new approach for managing this challenging condition.

Pulmonary Hypertension: Pharmacological and Non-Pharmacological Therapies

Pulmonary hypertension (PH) is a severe and chronic disease characterized by increased pulmonary vascular resistance and remodeling, often precipitating right-sided heart dysfunction and death. Although the condition is progressive and incurable, current therapies for the disease focus on multiple different drugs and general supportive therapies to manage symptoms and prolong survival, ranging from medications more specific to pulmonary arterial hypertension (PAH) to exercise training. Moreover, there are multiple studies exploring novel experimental drugs and therapies including unique neurostimulation, to help better manage the disease. Here, we provide a narrative review focusing on current PH treatments that target multiple underlying biochemical mechanisms, including imbalances in vasoconstrictor-vasodilator and autonomic nervous system function, inflammation, and bone morphogenic protein (BMP) signaling. We also focus on the potential of novel therapies for managing PH, focusing on multiple types of neurostimulation including acupuncture. Lastly, we also touch upon the disease's different subgroups, clinical presentations and prognosis, diagnostics, demographics, and cost.

Post-transcriptional regulation of IFI16 promotes inflammatory endothelial pathophenotypes observed in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a progressive disease driven by endothelial cell inflammation and dysfunction, resulting in the pathological remodeling of the pulmonary vasculature. Innate immune activation has been linked to PAH development; however, the regulation, propagation, and reversibility of the induction of inflammation in PAH is poorly understood. Here, we demonstrate a role for interferon inducible protein 16 (IFI16), an innate immune sensor, as a modulator of endothelial inflammation in pulmonary hypertension, utilizing human pulmonary artery endothelial cells (PAECs). Inflammatory stimulus of PAECs with IL-1β up-regulates IFI16 expression, inducing proinflammatory cytokine up-regulation and cellular apoptosis. IFI16 mRNA stability is regulated by post-transcriptional m6A modification, mediated by Wilms' tumor 1-associated protein (WTAP), a structural stabilizer of the methyltransferase complex, via regulation of m6A methylation of IFI16. Additionally, m6A levels are increased in the peripheral blood mononuclear cells of PAH patients compared to control, indicating that quantifying this epigenetic change in patients may hold potential as a biomarker for disease identification. In summary, our study demonstrates IFI16 mediates inflammatory endothelial pathophenotypes seen in pulmonary arterial hypertension.

Immune mediators in heart-lung communication

It is often the case that serious, end-stage manifestations of disease result from secondary complications in organs distinct from the initial site of injury or infection. This is particularly true of diseases of the heart-lung axis, given the tight anatomical connections of the two organs within a common cavity in which they collectively orchestrate the two major, intertwined circulatory pathways. Immune cells and the soluble mediators they secrete serve as effective, and targetable, messengers of signals between different regions of the body but can also contribute to the spread of pathology. In this review, we discuss the immunological basis of interorgan communication between the heart and lung in various common diseases, and in the context of organ crosstalk more generally. Gaining a greater understanding of how the heart and lung communicate in health and disease, and viewing disease progression generally from a more holistic, whole-body viewpoint have the potential to inform new diagnostic approaches and strategies for better prevention and treatment of comorbidities.

ORENITRAM's decadal journey: unveiling safety profiles and adverse event through a real-world pharmacovigilance study of FAERS events

BACKGROUND

ORENITRAM, an oral treprostinil formulation, was approved in 2013 for pulmonary arterial hypertension (PAH) treatment, necessitating ongoing safety monitoring.

RESEARCH DESIGN AND METHODS

This retrospective analysis used FDA Adverse Event Reporting System data from Q4 2013 to Q4 2023, employing disproportionality analysis and the reporting odds ratio (ROR) to identify adverse events (AEs) linked with ORENITRAM.

RESULTS

Out of 15,660,695 reports, ORENITRAM was the primary suspect in 10,125 cases. We identified 174 significant adverse events across 27 organ systems, with notable issues like pulmonary edema, ascites, and ventricular fibrillation. Females reported more AEs (75.6%) than males (24.0%), suggesting potential metabolic differences. AEs were most common within 30 days of starting treatment or after one year.

CONCLUSIONS

The study indicates significant safety issues with ORENITRAM, including serious unexpected events such as pulmonary edema, ascites, and ventricular fibrillation. These findings highlight the necessity for careful clinical monitoring and effective risk management, particularly with observed gender differences in AE profiles. The study's retrospective nature and reliance on spontaneous reports may affect result generalizability.

The Influence of Pulmonary Arterial Hypertension In Pregnancy: A Review

Pulmonary arterial hypertension (PAH) is a severe condition characterized by increased pulmonary vascular resistance and right ventricular failure. This review examines the intersection of PAH and pregnancy, highlighting the significant physiological, hemodynamic, and hormonal changes that exacerbate PAH during gestation. Pregnancy is contraindicated in PAH patients due to high maternal and fetal morbidity and mortality rates. However, some patients choose to continue their pregnancies, necessitating a comprehensive understanding of the implications and management strategies. Effective management of PAH in pregnant patients involves individualized treatment plans. Prepartum management focuses on optimizing therapy and monitoring hemodynamic status. Prostacyclin analogs and phosphodiesterase inhibitors are commonly used, though their safety profiles require further investigation. Intrapartum management prioritizes preventing right ventricular failure, utilizing therapies such as intravenous epoprostenol, inhaled iloprost, and inhaled nitric oxide. Managing PAH in pregnancy requires careful planning, continuous monitoring, and tailored therapeutic strategies to navigate the complex interplay of physiological changes and mitigate risks. Future research should focus on elucidating the pathophysiology of PAH during pregnancy and developing safer, more effective treatments to improve maternal and fetal outcomes.

Assessing the precision of machine learning for diagnosing pulmonary arterial hypertension: a systematic review and meta-analysis of diagnostic accuracy studies

Introduction

Pulmonary arterial hypertension (PAH) is a severe cardiovascular condition characterized by pulmonary vascular remodeling, increased resistance to blood flow, and eventual right heart failure. Right heart catheterization (RHC) is the gold standard diagnostic technique, but due to its invasiveness, it poses risks such as vessel and valve injury. In recent years, machine learning (ML) technologies have offered non-invasive alternatives combined with ML for improving the diagnosis of PAH.

Objectives

The study aimed to evaluate the diagnostic performance of various methods, such as electrocardiography (ECG), echocardiography, blood biomarkers, microRNA, chest x-ray, clinical codes, computed tomography (CT) scan, and magnetic resonance imaging (MRI), combined with ML in diagnosing PAH.

Methods

The outcomes of interest included sensitivity, specificity, area under the curve (AUC), positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR). This study employed the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool for quality appraisal and STATA V.12.0 for the meta-analysis.

Results

A comprehensive search across six databases resulted in 26 articles for examination. Twelve articles were categorized as low-risk, nine as moderate-risk, and five as high-risk. The overall diagnostic performance analysis demonstrated significant findings, with sensitivity at 81% (95% CI = 0.76-0.85, p < 0.001), specificity at 84% (95% CI = 0.77-0.88, p < 0.001), and an AUC of 89% (95% CI = 0.85-0.91). In the subgroup analysis, echocardiography displayed outstanding results, with a sensitivity value of 83% (95% CI = 0.72-0.91), specificity value of 93% (95% CI = 0.89-0.96), PLR value of 12.4 (95% CI = 6.8-22.9), and DOR value of 70 (95% CI = 23-231). ECG demonstrated excellent accuracy performance, with a sensitivity of 82% (95% CI = 0.80-0.84) and a specificity of 82% (95% CI = 0.78-0.84). Moreover, blood biomarkers exhibited the highest NLR value of 0.50 (95% CI = 0.42-0.59).

Conclusion

The implementation of echocardiography and ECG with ML for diagnosing PAH presents a promising alternative to RHC. This approach shows potential, as it achieves excellent diagnostic parameters, offering hope for more accessible and less invasive diagnostic methods.

Systematic Review Registration

PROSPERO (CRD42024496569).

The Relevance of the Endothelium in Cardiopulmonary Disorders

The endothelium is a cell monolayer that lines vessels and separates tissues from blood flow. Endothelial cells (ECs) have a multitude of functions, including regulating blood flow and systemic perfusion through changes in vessel diameter. When an injury occurs, the endothelium is affected by altering its functions and structure, which leads to endothelial dysfunction, a characteristic of many vascular diseases. Understanding the role that the endothelium plays in pulmonary vascular and cardiopulmonary diseases, and exploring new therapeutic strategies is of utmost importance to advance clinically. Currently, there are several treatments able to improve patients' quality of life, however, none are effective nor curative. This review examines the critical role of the endothelium in the pulmonary vasculature, investigating the alterations that occur in ECs and their consequences for blood vessels and potential molecular targets to regulate its alterations. Additionally, we delve into promising non-pharmacological therapeutic strategies, such as exercise and diet. The significance of the endothelium in cardiopulmonary disorders is increasingly being recognized, making ECs a relevant target for novel therapies aimed at preserving their functional and structural integrity.

The impact of group II pulmonary hypertension on congestive heart failure patients admitted with ST elevation myocardial infarction, a nationwide study

Background

Pulmonary hypertension (PH) is a condition where the blood pressure increases in the pulmonary arteries, leading to reduced oxygen delivery to the body's tissues due to increased blood flow resistance. This condition can result in right ventricular hypertrophy, low cardiac output, and ischemia. In this study, the authors aim to investigate the impact of group II PH (GIIPH) on patients with congestive heart failure who were admitted with ST elevation myocardial infarction (STEMI) through a retrospective cohort study.

Methods

Using the National Inpatient Sample (NIS) database from 2017 to 2020, a retrospective cross-sectional study of adult patients with a principal diagnosis of STEMI with a secondary diagnosis with or without GIIPH according to ICD-10 (International Classification of Disease, 10th edition) codes. Several demographics, including age, race, and gender, were analyzed. The primary endpoint was mortality, while the secondary endpoints included cardiogenic shock, mechanical intubation, length of stay in days, and patient charge in dollars. Multivariate logistic regression model analysis was used to adjust for confounders, with a P value less than 0.05 considered statistically significant.

Results

The study included 26,925 patients admitted with a STEMI, 95 of whom had GIIPH. The mean age for patients with and without PH was 66.6 and 67.5 years, respectively. In the PH group, 37% were females compared to 34% in the non-PH group. The in-hospital mortality rate was higher in the PH group (31.6% vs. 9.6%, P<0.001, adjusted odds ratio (aOR) =3.33, P=0.02). The rates and adjusted odds of cardiogenic shock and mechanical ventilation were higher in the PH groups (aOR =1.15 and 2.14, respectively) but not statistically significant. Patients with PH had a longer length of stay and a higher total charge.

Conclusions

GIIPH was associated with worse clinical and economic outcomes in heart failure patients admitted with STEMI.

A peripheral system disease-Pulmonary hypertension

Pulmonary hypertension (PH) is a cardiovascular disorder characterized by substantial morbidity and mortality rates. It is a chronic condition characterized by intricate pathogenesis and uncontrollable factors. We summarized the pathological effects of estrogen, genetics, neuroinflammation, intestinal microbiota, metabolic reorganization, and histone modification on PH. PH is not only a pulmonary vascular disease, but also a systemic disease. The findings emphasize that the onset of PH is not exclusively confined to the pulmonary vasculature, consequently necessitating treatment approaches that extend beyond targeting pulmonary blood vessels. Hence, the research on the pathological mechanism of PH is not limited to target organs such as pulmonary vessels, but also focuses on exploring other fields (such as estrogen, genetics, neuroinflammation, intestinal microbiota, metabolic reorganization, and histone modification).

The one-minute sit-to-stand-test performance is associated with health-related quality of life in patients with pulmonary hypertension

INTRODUCTION

Patients with pulmonary hypertension (PH) have an impaired functional capacity and poor health-related quality of life (HRQoL). The one-minute sit-to-stand test (1-min STST) can be used for the assessment of functional capacity.

AIMS

Our aim was to evaluate the 1-min STST performance and its association with patient-reported HRQoL in patients with PH.

METHODS

We prospectively assessed functional capacity in 98 PH patients (mean age 66 ± 15 years, 55% female) using the 1-min STST. Patients had to stand up and sit down from a chair as many times as possible within one minute. Patients' HRQoL was evaluated with the Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR) questionnaire, which consists of the three subcategories symptoms, activities and quality of life (QoL).

RESULTS

We observed a significant correlation of the 1-min STST performance with all HRQoL subcategories assessed with the CAMPHOR questionnaire: A lower number of 1-min STST repetitions correlated with more symptoms (rs = -.398, p < .001), worse functioning (rs = -.551, p < .001) and a decreased QoL (rs = -.407, p < .001). Furthermore, in the multivariable linear regression analysis, adjusted for age, sex, body mass index (BMI) and mean pulmonary artery pressure (mPAP), lower 1-min STST performance was an independent predictor for worse symptoms (est. β = -0.112, p = .003), activities (est. β = -0.198, p < .001) and QoL (est. β = -0.130, p < .001) assessed with the CAMPHOR questionnaire.

CONCLUSION

Our results indicate that regardless of age, sex, BMI and mPAP the 1-min STST performance is associated with all CAMPHOR HRQoL subcategories in patients with PH. Therefore, the 1-min STST performance might be a new option to assess functional capacity correlated to HRQoL in patients with PH.

Formulation and evaluation of inhaled Sildenafil-loaded PLGA microparticles for treatment of pulmonary arterial hypertension (PAH): A novel high drug loaded formulation and scalable process via hot melt extrusion technology (Part Ⅰ)

In recent years, several techniques were employed to develop a local sustained pulmonary delivery of sildenafil citrate (SC) as an alternative for the intravenous and oral treatment of pulmonary arterial hypertension (PAH). Most of these methods, however, need to be improved due to limitations of scalability, low yield production, low drug loading, and stability issues. In this study, we report the use of hot-melt extrusion (HME) as a scalable process for making Poly (lactic-co-glycolic acid) (PLGA) microparticles with high SC load. The prepared particles were tested in vitro for local drug delivery to the lungs by inhalation. Sodium bicarbonate was included as a porogen in the formulation to make the particles more brittle and to impart favorable aerodynamic properties. Six formulations were prepared with different formulation compositions. Laser diffraction analysis was used to estimate the geometric particle size distribution of the microparticles. In-vitro aerodynamic performance was evaluated by the next-generation cascade impactor (NGI). It was reported in terms of an emitted dose (ED), an emitted fraction (EF%), a respirable fraction (RF%), a fine particle fraction (FPF%), a mass median aerodynamic diameter (MMAD), and geometric standard deviation (GSD). The formulations have also been characterized for surface morphology, entrapment efficiency, drug load, and in-vitro drug release. The results demonstrated that PLGA microparticles have a mean geometric particle size between 6 and 14 µm, entrapment efficiency of 77 to 89 %, and SC load between 17 and 33 % w/w. Fifteen percent of entrapped sildenafil was released over 24 h from the PLGA microparticles, and seventy percent over 7 days. The aerodynamic properties included fine particle fraction ranging between 19 and 33 % and an average mass median aerodynamic diameter of 6-13 µm.

Risk Factors for Pulmonary Embolism in Individuals Infected with SARS-CoV2-A Single-Centre Retrospective Study

The emergence of SARS-CoV2 has presented itself as a significant global health crisis. The prevalence of thrombotic events is known to be high in these patients, affecting various organ systems, sometimes leading to cutaneous thrombosis, pulmonary embolism (PE), stroke, or coronary thrombosis. The available evidence suggests that thromboembolism, hypercoagulability, and the excessive production of proinflammatory cytokines play a significant role in the development of multiorgan failure. Methodology: This retrospective single-centre study was conducted at "Victor Babes" University of Medicine and Pharmacy from Timisoara, Romania, involving a total of 420 patients diagnosed with COVID-19. We separated them into a CONTROL group that included 319 patients, and an intervention group (PE) with 101 patients that, subsequent to infection with the virus, developed pulmonary embolism. The study included the reporting of demographic data, laboratory findings, and comorbidities. Results: Out of a total of 420 patients, 24% experienced pulmonary embolism, while 21.42% died. Arterial thrombotic events were found to be associated with factors such as age, cardiovascular disease, levels of white blood cells, D-dimers, and albumin in the blood. The findings of the study indicate that there is an independent association between pulmonary thrombosis and hypertension (odds ratio (OR): 1.1; 95% confidence interval (CI): 0.7 to 1.7; p = 0.6463), cancer (OR: 1.1; 95% CI: 0.6 to 2.3; p = 0.6014), and COPD (OR: 1.2; 95% CI: 0.6 to 2.3; p = 0.4927). On the other hand, there is a stronger correlation between PE and obesity (OR: 2.8; 95% CI: 1.7 to 4.6; p < 0.0001), diabetes (OR: 3.3; 95% CI: 2 to 5.3; p < 0.0001), and dyslipidemia (OR: 3.6; 95% CI: 2.3 to 5.8; p < 0.0001) in a multivariable regression logistic model. Conclusions: Patients diagnosed with severe forms of COVID-19 display a comparable incidence of arterial thrombotic events, which have been linked to poor survival rates.

Causal effect of interleukin (IL)-6 on blood pressure and hypertension: A mendelian randomization study

To examine whether circulating interleukin-6 (IL-6) levels (CirIL6) have a causal effect on blood pressure using Mendelian randomization (MR) methods. We used data from genome-wide association studies (GWAS) of European ancestry to obtain genetic instruments for circulating IL-6 levels and blood pressure measurements. We applied several robust MR methods to estimate the causal effects and to test for heterogeneity and pleiotropy. We found that circulating IL-6 had a significant positive causal effect on systolic blood pressure (SBP) and pulmonary arterial hypertension (PAH), but not on diastolic blood pressure (DBP) or hypertension. We found that as CirIL6 genetically increased, SBP increased using Inverse Variance Weighted (IVW) method (for ukb-b-20175, β = 0.082 with SE = 0.032, P = 0.011; for ukb-a-360, β = 0.075 with SE = 0.031, P = 0.014) and weighted median (WM) method (for ukb-b-20175, β = 0.061 with SE = 0.022, P = 0.006; for ukb-a-360, β = 0.065 with SE = 0.027, P = 0.014). Moreover, CirIL6 may be associated with an increased risk of PAH using WM method (odds ratio (OR) = 15.503, 95% CI, 1.025-234.525, P = 0.048), but not with IVW method. Our study provides novel evidence that circulating IL-6 has a causal role in the development of SBP and PAH, but not DBP or hypertension. These findings suggest that IL-6 may be a potential therapeutic target for preventing or treating cardiovascular diseases and metabolic disorders. However, more studies are needed to confirm the causal effects of IL-6 on blood pressure and to elucidate the underlying mechanisms and pathways.

Effect of IL-17 on pulmonary artery smooth muscle cells and connective tissue disease-associated pulmonary arterial hypertension

OBJECTIVE

To explore the role of interleukin (IL)-17 in connective tissue disease-associated pulmonary arterial hypertension (CTD-PAH) and to investigate its possible mechanism on pulmonary artery smooth muscle cells (PASMCs).

METHODS

Enzyme-linked immunosorbent assay (ELISA) were used to compare levels of serum IL-17 in patients with CTD-PAH and healthy controls (HCs). After treatment for 3 months, the serum IL-17 levels were tested in CTD-PAH. ELISA and immunohistochemistry were used to compare levels of serum IL-17 and numbers of pulmonary artery IL-17+ cells, respectively, in a rat model of monocrotaline-induced PAH and untreated rats. Proliferation, migration, and inflammatory factors expression of PASMCs were assessed after stimulation with different concentrations of IL-17 for various time periods. Proteins in the mitogen-activated protein kinase (MAPK) pathway were examined by western blot.

RESULTS

Levels of IL-17 were upregulated in patients with CTD-PAH compared to HCs. After 3 months of treatment, serum IL-17 levels were downregulated with pulmonary artery pressure amelioration. Moreover, serum IL-17 levels and numbers of IL-17+ cells infiltrating lung arterioles were increased in PAH model rats. IL-17 could dose- and time-dependently promote proliferation and migration of PASMCs as well as time-dependently induce IL-6 and intercellular cell adhesion molecule-1 (ICAM-1) expression. The levels of MKK6 increased after IL-17 treatment. Inhibition of MAPK decreased proliferation of PASMCs.

CONCLUSION

Levels of IL-17 may increase in CTD-PAH, and IL-17 promotes proliferation, migration, and secretion of IL-6 and ICAM in PASMCs, respectively, which likely involves the p-38 MAPK pathway.

Pharmacological Agents and Potential New Therapies in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a progressive disease characterized by an imbalance between vasoactive mediators, which causes vascular remodeling, increased pulmonary vascular resistance, and right ventricular overload, ultimately leading to heart failure and death. A metabolic theory has been suggested to explain the pathophysiology of PAH whereby abnormalities in mitochondrial biogenesis can trigger a hyperproliferative and apoptosis-resistant phenotype in cardiopulmonary and malignant cells, leading to mitochondrial dysfunction, which in turn causes the Warburg effect. This can culminate in the mitophagy of pulmonary vessels and cardiomyocytes. The present narrative review focuses on the pathophysiology of PAH, the pharmacological agents currently available for its treatment, and promising and challenging areas of therapeutic investigation.

Mitochondrial Dynamics in Pulmonary Hypertension

Mitochondria are essential organelles for energy production, calcium homeostasis, redox signaling, and other cellular responses involved in pulmonary vascular biology and disease processes. Mitochondrial homeostasis depends on a balance in mitochondrial fusion and fission (dynamics). Mitochondrial dynamics are regulated by a viable circadian clock. Hypoxia and nicotine exposure can cause dysfunctions in mitochondrial dynamics, increases in mitochondrial reactive oxygen species generation and calcium concentration, and decreases in ATP production. These mitochondrial changes contribute significantly to pulmonary vascular oxidative stress, inflammatory responses, contractile dysfunction, pathologic remodeling, and eventually pulmonary hypertension. In this review article, therefore, we primarily summarize recent advances in basic, translational, and clinical studies of circadian roles in mitochondrial metabolism in the pulmonary vasculature. This knowledge may not only be crucial to fully understanding the development of pulmonary hypertension, but also greatly help to create new therapeutic strategies for treating this devastating disease and other related pulmonary disorders.

Polyelectrolyte-based solid dispersions for enhanced dissolution and pH-Independent controlled release of sildenafil citrate

The aim of this study was to design a novel matrix tablet with enhanced dissolution and pH-independent controlled release of sildenafil citrate (SIL), a drug with pH-dependent solubility, by using solid dispersions (SDs) and polyelectrostatic interactions. SIL-loaded SDs were prepared using various polymeric carriers such as poloxamer 188, poloxamer 407, Soluplus®, polyvinylpyrrolidone (PVP) K 12, and PVP K 17 by the solvent evaporation method. Among these polymers, Soluplus® was found to be the most effective in SDs for enhancing the drug dissolution over 6 h in pH 6.8 intestinal fluid. SIL was well dispersed in Soluplus®-based SDs in an amorphous form. When the Soluplus®-based SDs were added in the tablet containing positively charged chitosan and negatively charged Eudragit® L100, the drug release rate was further modulated in a controlled manner. The charge density of the tablet was higher at pH 6.8 than at pH 1.2 due to the polyelectrostatic interaction between chitosan and Eudragit® L100. This interaction could provide a pH-independent controlled release of SIL. Our study demonstrates that a combinatory approach of Soluplus®-based SDs and polyelectrostatic interactions can improve the dissolution and pH-independent release performance of SIL. This approach could be a promising pharmaceutical strategy to design a matrix tablet of poorly water-soluble drugs for the enhanced bioavailability.

Blinded sample size recalculation in multiple composite population designs with normal data and baseline adjustments

The increasing interest in subpopulation analysis has led to the development of various new trial designs and analysis methods in the fields of personalized medicine and targeted therapies. In this paper, subpopulations are defined in terms of an accumulation of disjoint population subsets and will therefore be called composite populations. The proposed trial design is applicable to any set of composite populations, considering normally distributed endpoints and random baseline covariates. Treatment effects for composite populations are tested by combining p-values, calculated on the subset levels, using the inverse normal combination function to generate test statistics for those composite populations while the closed testing procedure accounts for multiple testing. Critical boundaries for intersection hypothesis tests are derived using multivariate normal distributions, reflecting the joint distribution of composite population test statistics given no treatment effect exists. For sample size calculation and sample size, recalculation multivariate normal distributions are derived which describe the joint distribution of composite population test statistics under an assumed alternative hypothesis. Simulations demonstrate the absence of any practical relevant inflation of the type I error rate. The target power after sample size recalculation is typically met or close to being met.

Pulmonary Assessment of the Liver Transplant Recipient

Respiratory symptoms and hypoxemia can complicate chronic liver disease and portal hypertension. Various pulmonary disorders affecting the pleura, lung parenchyma, and pulmonary vasculature are seen in end-stage liver disease, complicating liver transplantation (LT). Approximately 8% of cirrhotic patients in an intensive care unit develop severe pulmonary problems. These disorders affect waiting list mortality and posttransplant outcomes. A thorough history, physical examination, and appropriate laboratory tests help diagnose and assess the severity to risk stratify pulmonary diseases before LT. Hepatopulmonary syndrome (HPS), portopulmonary hypertension (POPH), and hepatic hydrothorax (HH) are respiratory consequences specific to cirrhosis and portal hypertension. HPS is seen in 5-30% of cirrhosis cases and is characterized by impaired oxygenation due to intrapulmonary vascular dilatations and arteriovenous shunts. Severe HPS is an indication of LT. The majority of patients with HPS resolve their hypoxemia after LT. When pulmonary arterial hypertension occurs in patients with portal hypertension, it is called POPH. All other causes of pulmonary arterial hypertension should be ruled out before labeling as POPH. Since severe POPH (mean pulmonary artery pressure [mPAP] >50 mm Hg) is a relative contraindication for LT, it is crucial to screen for POPH before LT. Those with moderate POPH (mPAP >35 mm Hg), who improve with medical therapy, will benefit from LT. A transudative pleural effusion called hepatic hydrothorax (HH) is seen in 5-10% of people with cirrhosis. Refractory cases of HH benefit from LT. In recent years, increasing clinical expertise and advances in the medical field have resulted in better outcomes in patients with moderate to severe pulmonary disorders, who undergo LT.

Role of micro-RNAs 21, 124 and other novel biomarkers in distinguishing between group 1 WHO pulmonary hypertension and group 2, 3 WHO pulmonary hypertension

BACKGROUND

Pulmonary hypertension "PH" is considered a serious cardiovascular disease. World Health Organization divided PH into groups depending on many factors like pathological, hemodynamic, and clinical pictures. Lately, various micro-RNAs "miRNAs" and other novel biomarkers like endoglin and asymmetric dimethylarginine "ADMA" might have a role in diagnosis of PH and may differentiate between pulmonary arterial hypertension "PAH" and non-PAH. The purpose of the study is to show the role of miR-21, miR-124, endoglin and ADMA in the diagnosis of PH and distinguishing between WHO group 1 PH and WHO group 2 and 3 PH and to identify patients who might benefit from non-invasive and inexpensive tools to diagnose PAH.

RESULTS

miR-21 was upregulated in group 1 PH, and there was significant difference between group 1 PH as compared with group 2 PH, group 3 PH and control; miR-124 was down-regulated in group 1 PH with highly significant difference between group 1 and group 2 PH and control but no significant difference with group 3 PH, endoglin was elevated in group 1 PH with a significant difference as compared to group 2 PH, group 3 PH and control. ADMA was elevated in group 1 PH as compared to control; however, there was no significant difference between it and group 2, 3 PH.

CONCLUSIONS

miR-21, miR-124, endoglin and ADMA are good biomarkers to diagnose PH; however, only miR-21 and endoglin could distinguish group 1 PH from group 2 and 3 PH.

Metformin protects against pulmonary hypertension-induced right ventricular dysfunction in an age- and sex-specific manner independent of cardiac AMPK

Right ventricular (RV) function is the strongest predictor of survival in age-related heart failure as well as other clinical contexts in which aging populations suffer significant morbidity and mortality. However, despite the significance of maintaining RV function with age and disease, mechanisms of RV failure remain poorly understood and no RV-directed therapies exist. The antidiabetic drug and AMP-activated protein kinase (AMPK) activator metformin protects against left ventricular dysfunction, suggesting cardioprotective properties may translate to the RV. Here, we aimed to understand the impact of advanced age on pulmonary hypertension (PH)-induced right ventricular dysfunction. We further aimed to test whether metformin is cardioprotective in the RV and whether the protection afforded by metformin requires cardiac AMPK. We used a murine model of PH by exposing adult (4-6 mo) and aged (18 mo) male and female mice to hypobaric hypoxia (HH) for 4 wk. Cardiopulmonary remodeling was exacerbated in aged mice compared with adult mice as evidenced by elevated RV weight and impaired RV systolic function. Metformin attenuated HH-induced RV dysfunction but only in adult male mice. Metformin still protected the adult male RV even in the absence of cardiac AMPK. Together, we suggest that aging exacerbates PH-induced RV remodeling and that metformin may represent a therapeutic option for this disease in a sex- and age-dependent manner, but in an AMPK-independent manner. Ongoing efforts are aimed at elucidating the molecular basis for RV remodeling as well as delineating the mechanisms of cardioprotection provided by metformin in the absence of cardiac AMPK.NEW & NOTEWORTHY Right ventricular (RV) function predicts survival in age-related disease, yet mechanisms of RV failure are unclear. We show that aged mice undergo exacerbated RV remodeling compared with young. We tested the AMPK activator metformin to improve RV function and show that metformin attenuates RV remodeling only in adult male mice via a mechanism that does not require cardiac AMPK. Metformin is therapeutic for RV dysfunction in an age- and sex-specific manner independent of cardiac AMPK.

Differential responses of pulmonary vascular cells from PAH patients and controls to TNFα and the effect of the BET inhibitor JQ1

BACKGROUND

Pulmonary arterial hypertension (PAH) encompasses a group of diseases characterized by raised pulmonary vascular resistance, resulting from vascular remodelling and inflammation. Bromodomain and extra-terminal (BET) proteins are required for the expression of a subset of NF-κB-induced inflammatory genes which can be inhibited by the BET mimic JQ1+. We hypothesised that JQ+ would supress TNFα-driven inflammatory responses in human pulmonary vascular cells from PAH patients.

METHODS

Immunohistochemical staining of human peripheral lung tissue (N = 14 PAH and N = 12 non-PAH) was performed for the BET proteins BRD2 and 4. Human pulmonary microvascular endothelial cells (HPMEC) and pulmonary artery smooth muscle cells (HPASMC) from PAH patients (N = 4) and non-PAH controls (N = 4) were stimulated with TNFα in presence or absence of JQ1+ or its inactive isomer JQ1-. IL-6 and -8 mRNA was measured by RT-qPCR and protein levels by ELISA. Chromatin immunoprecipitation analysis was performed using EZ-ChIP™ and NF-κB p65 activation determined using a TransAm kit. MTT assay was used to measure cell viability.

RESULTS

Nuclear staining of BRD2 and BRD4 was significantly (p < 0.0001) increased in the lung vascular endothelial and smooth muscle cells from PAH patients compared to controls with normal lung function. TNFα-driven IL-6 release from both HPMECs and HPASMCs was greater in PAH cells than control cells. Levels of CXCL8/IL-8 protein release was higher in PAH HPASMCs than in control cells with similar release observed in HPMECs. TNFα-induced recruitment of activated NF-κB p65 to the IL-6 and CXCL8/IL-8 promoters were similar in both cell types and between subject groups. JQ1+ suppressed TNFα-induced IL-6 and CXCL8/IL-8 release and mRNA expression to a comparable extent in control and PAH HPMECs and HPASMCs. JQ1 had a greater efficacy on IL-6 release in HPMEC and on CXCL8/IL-8 release in HPASMC.

CONCLUSION

BET inhibition decreases TNFα driven inflammation in primary pulmonary vascular cells. The anti-inflammatory actions of JQ1 suggests distinct cell-specific regulatory control of these genes. BET proteins could be a target for future therapies for PAH.

CTLA-4 Expression Is a Promising Biomarker of Idiopathic Pulmonary Arterial Hypertension and Allows Differentiation of the Type of Pulmonary Hypertension

Pulmonary arterial hypertension (PAH) is an increasingly frequently diagnosed disease, the molecular mechanisms of which have not been thoroughly investigated. The aim of our study was to investigate subpopulations of lymphocytes to better understand their role in the molecular pathomechanisms of various types of PAH and to find a suitable biomarker that could be useful in the differential diagnosis of PAH. Using flow cytometry, we measured the frequencies of lymphocyte subpopulations CD4+CTLA-4+, CD8+ CTLA-4+ and CD19+ CTLA-4+ in patients with different types of PAH, namely pulmonary arterial hypertension associated with congenital heart disease (CHD-PAH), pulmonary arterial hypertension associated with connective tissue disorders (CTD-PAH), chronic thromboembolic pulmonary hypertension (CTEPH) and idiopathic pulmonary arterial hypertension (iPAH), and in an age- and sex-matched control group in relation to selected clinical parameters. Patients in the iPAH group had the significantly highest percentage of CD4+CTLA-4+ T lymphocytes among all PAH groups, as compared to those in the control group (p < 0.001), patients with CTEPH (p < 0.001), CTD-PAH (p < 0.001) and CHD-PAH (p < 0.01). In iPAH patients, the percentages of CD4+CTLA-4+ T cells correlated strongly positively with the severity of heart failure New York Heart Association (NYHA) Functional Classification (r = 0.7077, p < 0.001). Moreover, the percentage of B CD19+CTLA-4+ cells strongly positively correlated with the concentration of NT-proBNP (r = 0.8498, p < 0.001). We have shown that statistically significantly higher percentages of CD4+CTLA-4+ (p ≤ 0.01) and CD8+ CTLA-4+ (p ≤ 0.001) T cells, measured at the time of iPAH diagnosis, were found in patients who died within 5 years of the diagnosis, which allows us to consider both of the above lymphocyte subpopulations as a negative prognostic/predictive factor in iPAH. CTLA-4 may be a promising biomarker of noninvasive detection of iPAH, but its role in planning the treatment strategy of PAH remains unclear. Further studies on T and B lymphocyte subsets are needed in different types of PAH to ascertain the relationships that exist between them and the disease.

Feline pulmonary hypertension: are we overlooking an important comorbidity?

Pulmonary hypertension (PH) is a potential complication in many disease states, yet it has been largely overlooked in feline medicine. Recently, increased awareness of potential underlying causes has led to a wider understanding of the disease process in humans, with a focus on tailoring therapy to include specific treatment of the underlying etiology. Most of these treatments are not yet available in veterinary medicine, but as they move from the human to the veterinary field, it would be beneficial to better understand the forms of PH encountered in different species. Recently, diagnosis and classification of PH in dogs has been the focus of an American College of Veterinary Internal Medicine consensus statement, yet this condition has received little attention in cats. It is therefore our intention to raise awareness of this condition in cats and to propose a classification system for the types of PH seen in feline patients. As new medications are developed for the treatment of PH, it is important to recognize which forms of PH are seen in feline patients and understand the etiology of the disease. There are many reports of PH (or suspected PH based on echocardiographic assessment) in cats. In this review, we highlight the large number of conditions, and different etiologies, that are associated with PH. Improving understanding of this condition will bring us closer to being able to investigate the benefits of potential new diagnostics and therapies as they become available.

The Role of Bone Morphogenetic Protein Receptor Type 2 (BMPR2) and the Prospects of Utilizing Induced Pluripotent Stem Cells (iPSCs) in Pulmonary Arterial Hypertension Disease Modeling

Pulmonary arterial hypertension (PAH) is a progressive disease characterized by increased pulmonary vascular resistance (PVR), causing right ventricular hypertrophy and ultimately death from right heart failure. Heterozygous mutations in the bone morphogenetic protein receptor type 2 (BMPR2) are linked to approximately 80% of hereditary, and 20% of idiopathic PAH cases, respectively. While patients carrying a BMPR2 gene mutation are more prone to develop PAH than non-carriers, only 20% will develop the disease, whereas the majority will remain asymptomatic. PAH is characterized by extreme vascular remodeling that causes pulmonary arterial endothelial cell (PAEC) dysfunction, impaired apoptosis, and uncontrolled proliferation of the pulmonary arterial smooth muscle cells (PASMCs). To date, progress in understanding the pathophysiology of PAH has been hampered by limited access to human tissue samples and inadequacy of animal models to accurately mimic the pathogenesis of human disease. Along with the advent of induced pluripotent stem cell (iPSC) technology, there has been an increasing interest in using this tool to develop patient-specific cellular models that precisely replicate the pathogenesis of PAH. In this review, we summarize the currently available approaches in iPSC-based PAH disease modeling and explore how this technology could be harnessed for drug discovery and to widen our understanding of the pathophysiology of PAH.

Patient-specific and gene-corrected induced pluripotent stem cell-derived endothelial cells elucidate single-cell phenotype of pulmonary veno-occlusive disease

Pulmonary veno-occlusive disease (PVOD) is a rare form of pulmonary hypertension characterized by the preferential remodeling of the pulmonary venules. Hereditary PVOD is caused by biallelic variants of the EIF2AK4 gene. Three PVOD patients who carried the compound heterozygous variants of EIF2AK4 and two healthy controls were recruited and induced pluripotent stem cells (iPSCs) were generated from human peripheral blood mononuclear cells (PBMCs). The EIF2AK4 c.2965C>T variant (PVOD#1), c.3460A>T variant (PVOD#2), and c.4832_4833insAAAG variant (PVOD#3) were corrected by CRISPR-Cas9 in PVOD-iPSCs to generate isogenic controls and gene-corrected-iPSCs (GC-iPSCs). PVOD-iPSC-endothelial cells (ECs) exhibited a decrease in GCN2 protein and mRNA expression when compared with control and GC-ECs. PVOD-ECs exhibited an abnormal EC phenotype featured by excessive proliferation and angiogenesis. The abnormal phenotype of PVOD-ECs was normalized by protein kinase B inhibitors AZD5363 and MK2206. These findings help elucidate the underlying molecular mechanism of PVOD in humans and to identify promising therapeutic drugs for treating the disease.

Echocardiographic changes after arteriovenous fistula creation in hemodialysis patients

BACKGROUND

Pulmonary hypertension (PH) is common in end-stage renal disease (ESRD) patients and is associated with increased all-cause and cardiovascular mortality in this group. There is scarce data on the long-term effect of arteriovenous fistula (AVF) creation on pulmonary hypertension (PH) and the reflected changes in echocardiographic measurements.

MATERIALS AND METHODS

This is a retrospective study of 54 patients who underwent AVF creation between 2009 and 2014 and with echocardiographic evaluations before and after surgery. We analyzed pairwise changes in right ventricular systolic pressure (RVSP), right atrial pressure (RAP) during systole, left ventricular mass (LVM), tricuspid regurgitation (TR), mitral E/E' ratio, and ejection fraction (EF), as well as the factors that predicted change in RVSP after surgery.

RESULTS

The median time for the preoperative echocardiogram was 0.3 years (interquartile range (IQR) 0.2 - 0.7 years) prior to AVF creation, while the follow-up echo was done 1.3 (0.6 - 2.1) years after surgery. 67% of the patients had RVSP &gt; 37 mmHg at baseline. There was a significant reduction in RVSP after AVF creation compared to baseline (median 33 (IQR 26 - 43) vs. 46 mmHg, p = 0.0015), with 59% of the patients experiencing a decrease and 19% remaining stable. There were also significant decreases in LVM (201 (143 - 256) vs. 215 (163 - 276), p = 0.045) and RAP systole (10 (10 - 15) vs. 3 (3 - 8); p &lt; 0.001) after surgery. Higher preoperative weight (p = 0.038) and RVSP (p = 0.006), and use of loop diuretics (p = 0.015) were significantly associated with improvement in RVSP after AVF creation.

CONCLUSION

Our results suggest that AVF creation is associated with a significant reduction or stable measurements of RVSP in the ESRD population, likely due to an improvement in volume status.

Recent Advances in the Treatment of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a disease in which stenosis or obstruction of the pulmonary arteries (PAs) causes an increase in PA pressure, leading to right-sided heart failure and death. Basic research has revealed a decrease in the levels of endogenous vasodilators, such as prostacyclin, and an increase in the levels of endogenous vasoconstrictors, such as endothelin, in patients with PAH, leading to the development of therapeutic agents. Currently, therapeutic agents for PAH target three pathways that are selective for PAs: the prostacyclin, endothelin, and nitric oxide pathways. These treatments improve the prognosis of PAH patients. In this review, we introduce new drug therapies and provide an overview of the current therapeutic agents.

Role of solid lipid nanoparticle for the delivery of Lipophilic Drugs and Herbal Medicines in the treatment of pulmonary hypertension

Pulmonary arterial hypertension (PAH) is an uncommon condition marked by elevated pulmonary artery pressure that leads to right ventricular failure. The majority of drugs are now been approved by FDA for PAH, however, several biopharmaceutical hindrances lead to failure of the therapy. Various novel drug delivery systems are available in the literature from which lipid-based nanoparticles i.e. solid lipid nanoparticle is widely investigated for improving the solubility and bioavailability of drugs. In this paper, the prototype phytoconstituents used in pulmonary arterial hypertension have limited solubility and bioavailability. We highlighted the novel concepts of SLN for lipophilic phytoconstituents with their potential applications. This paper also reviews the present state of the art regarding production techniques for SLN like High-Pressure Homogenization, Micro-emulsion Technique, and Phase Inversion Temperature Method, etc. Furthermore, toxicity aspects and in vivo fate of SLN are also highlighted in this review. In a nutshell, safer delivery of phytoconstituents by SLN added a novel feather to the cap of successful drug delivery technologies.

Computational models of ventricular mechanics and adaptation in response to right-ventricular pressure overload

Pulmonary arterial hypertension (PAH) is associated with substantial remodeling of the right ventricle (RV), which may at first be compensatory but at a later stage becomes detrimental to RV function and patient survival. Unlike the left ventricle (LV), the RV remains understudied, and with its thin-walled crescent shape, it is often modeled simply as an appendage of the LV. Furthermore, PAH diagnosis is challenging because it often leaves the LV and systemic circulation largely unaffected. Several treatment strategies such as atrial septostomy, right ventricular assist devices (RVADs) or RV resynchronization therapy have been shown to improve RV function and the quality of life in patients with PAH. However, evidence of their long-term efficacy is limited and lung transplantation is still the most effective and curative treatment option. As such, the clinical need for improved diagnosis and treatment of PAH drives a strong need for increased understanding of drivers and mechanisms of RV growth and remodeling (G&R), and more generally for targeted research into RV mechanics pathology. Computational models stand out as a valuable supplement to experimental research, offering detailed analysis of the drivers and consequences of G&R, as well as a virtual test bench for exploring and refining hypotheses of growth mechanisms. In this review we summarize the current efforts towards understanding RV G&R processes using computational approaches such as reduced-order models, three dimensional (3D) finite element (FE) models, and G&R models. In addition to an overview of the relevant literature of RV computational models, we discuss how the models have contributed to increased scientific understanding and to potential clinical treatment of PAH patients.

Potential of the TRPM7 channel as a novel therapeutic target for pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is an intractable vascular disease characterized by a progressive increase in pulmonary vascular resistance caused by pulmonary vascular remodeling, which ultimately leads to right-sided heart failure. PAH remains incurable, despite the development of PAH-targeted therapeutics centered on pulmonary artery relaxants. It is necessary to identify the target molecules that contribute to pulmonary artery remodeling. Transient receptor potential (TRP) channels have been suggested to modulate pulmonary artery remodeling. Our study focused on the transient receptor potential ion channel subfamily M, member 7, or the TRPM7 channel, which modulates endothelial-to-mesenchymal transition and smooth muscle proliferation in the pulmonary artery. In this review, we summarize the role and expression profile of TRPM7 channels in PAH progression and discuss TRPM7 channels as possible therapeutic targets. In addition, we discuss the therapeutic effect of a Chinese herbal medicine, Ophiocordyceps sinensis (OCS), on PAH progression, which partly involves TRPM7 inhibition.

Effects of oral anticoagulant therapy in patients with pulmonary diseases

Background

To evaluate the effect of oral anticoagulants (OACs) therapy, including vitamin K antagonist (VKA) and direct oral anticoagulants (DOAC) in patients with pulmonary diseases.

Methods

Literature from PubMed, MEDLINE, and Cochrane Library were screened until June 2022. Studies assessing OACs for pulmonary hypertension (PH), pulmonary embolism (PE), pulmonary fibrosis (PF), or chronic obstructive pulmonary disease (COPD) were evaluated for inclusion.

Results

Our study indicated that in patients with PH, PE, and COPD, OACs could significantly reduce the mortality risk, and the effects of VKA and DOACs without statistical difference in reducing the risk of recurrent embolism events. In patients with sclerosis-associated pulmonary arterial hypertension (SSc-PAH) or idiopathic pulmonary fibrosis (IPF), vitamin K antagonist (warfarin) significantly increased the mortality risk, while DOACs were not. As for the safety outcome of OACs, existing studies indicate that compared with patients treated with warfarin, the users of DOAC have a lower risk of major bleeding, while there is no statistical significance between them in non-major bleeding events. In current guidelines, the anticoagulation regimen for patients with pulmonary disease has not been defined. The results of our study confirm that DOACs (apixaban, rivaroxaban, dabigatran, and edoxaban) are superior to VKAs in the efficacy and safety outcomes of patients with pulmonary disease.

Conclusions

Oral anticoagulant therapy brings benefits to patients with PH, PE, or COPD, while the anticoagulation regimen for patients with SSc-PAH or IPF requires serious consideration. Compared with VKA, DOAC is a non-inferior option for anticoagulation in pulmonary disease treatment. Further studies are still needed to provide more reliable evidence about the safety outcome of pulmonary disease anticoagulation.

Genetic and functional analyses of TBX4 reveal novel mechanisms underlying pulmonary arterial hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) is a fatal disease, with approximately 10% of cases associated with genetic variants. Recent genetic studies have reported pathogenic variants in the TBX4 gene in patients with PAH, especially in patients with childhood-onset of the disease, but the pathogenesis of PAH caused by TBX4 variant has not been fully uncovered.

METHODS

We analysed the TBX4 gene in 75 Japanese patients with sporadic or familial PAH using a PCR-based bidirectional sequencing method. Detected variants were evaluated using in silico analyses as well as in vitro analyses including luciferase assay, immunocytochemistry and chromatin immunoprecipitation (ChIP) whether they have altered function. We also analysed the function of TBX4 using mouse embryonic lung explants with inhibition of Tbx4 expression.

RESULTS

Putative pathogenic variants were detected in three cases (4.0%). Our in vitro functional analyses revealed that TBX4 directly regulates the transcriptional activity of fibroblast growth factor 10 (FGF10), whereas the identified TBX4 variant proteins failed to activate the FGF10 gene because of disruption of nuclear localisation signal or poor DNA-binding affinity. Furthermore, ex vivo inhibition of Tbx4 resulted in insufficiency of lung morphogenesis along with specific downregulation of Tie2 and Kruppel-like factor 4 expression.

CONCLUSION

Our results implicate variants in TBX4 as a genetic cause of PAH in a subset of the Japanese population. Variants in TBX4 may lead to PAH through insufficient lung morphogenesis by disrupting the TBX4-mediated direct regulation of FGF10 signalling and pulmonary vascular endothelial dysfunction involving PAH-related molecules.

Salt-inducible kinases: new players in pulmonary arterial hypertension?

Salt-inducible kinases (SIKs) are serine/threonine kinases belonging to the AMP-activated protein kinase (AMPK) family. Accumulating evidence indicates that SIKs phosphorylate multiple targets, including histone deacetylases (HDACs) and cAMP response element-binding protein (CREB)-regulated transcriptional coactivators (CRTCs), to coordinate signaling pathways implicated in metabolism, cell growth, proliferation, apoptosis, and inflammation. These pathways downstream of SIKs are altered not only in pathologies like cancer, systemic hypertension, and inflammatory diseases, but also in pulmonary arterial hypertension (PAH), a multifactorial disease characterized by pulmonary vasoconstriction, inflammation and remodeling of pulmonary arteries owing to endothelial dysfunction and aberrant proliferation of smooth muscle cells (SMCs). In this opinion article, we present evidence of SIKs as modulators of key signaling pathways involved in PAH pathophysiology and discuss the potential of SIKs as therapeutic targets for PAH, emphasizing the need for deeper molecular insights on PAH.

Inhaled Iloprost Induces Long‐term Beneficial Hemodynamic Changes in Patients with Pulmonary Arterial Hypertension Receiving Combination Therapy

Inhaled iloprost is an established treatment for pulmonary arterial hypertension (PAH). However, the long‐term hemodynamic changes that inhaled iloprost induces are unclear. Here, we retrospectively enrolled 18 patients with PAH who received inhaled iloprost as add‐on to oral combination therapy from December 2016 to January 2021 at our institute in Japan. We then examined the changes in hemodynamic parameters induced by iloprost in these patients during right heart catheterization (RHC). To examine the long‐term effects of iloprost, we repeated the RHC examination at follow‐up (median time to follow‐up, 8.5 months). During both catheterization procedures, iloprost was administered by using an I‐neb AAD system (Philips NV). In a comparison of pre‐inhalation values at the first and follow‐up RHCs, inhaled iloprost significantly improved mean pulmonary artery pressure (mPAP; 39.9 ± 7.8 to 32.5 ± 7.2 mmHg, p = 0.016) and pulmonary vascular resistance (PVR; 588.5 ± 191.7 to 464.4 ± 188.5 dyn s cm⁻⁵, p = 0.047). During the follow‐up RHC, in a comparison of the pre‐inhalation and best recorded values out to 30 min after the end of iloprost inhalation, iloprost significantly decreased mPAP (32.5 ± 7.2 to 30.0 ± 6.6 mmHg, p = 0.007) and PVR (457.8 ± 181.4 to 386.2 ± 142.8 dyn s cm⁻⁵, p = 0.025) and significantly increased cardiac output (4.19 ± 0.91 to 4.64 ± 1.01 L/min, p = 0.035). Iloprost may have not only acute vasodilation effects but also long‐term hemodynamic benefits in PAH patients receiving combination therapy.

The Impact of Sex Chromosomes in the Sexual Dimorphism of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a sex-biased disease with a poorly understood female prevalence. Emerging research suggests that nonhormonal factors, such as the XX or XY sex chromosome complement and sex bias in gene expression, may also lead to sex-based differences in PAH incidence, penetrance, and progression. Typically, one of females' two X chromosomes is epigenetically silenced to offer a gender-balanced gene expression. Recent data demonstrate that the long noncoding RNA X-inactive specific transcript, essential for X chromosome inactivation and dosage compensation of X-linked gene expression, shows elevated levels in female PAH lung specimens compared with controls. This molecular event leads to incomplete inactivation of the females' second X chromosome, abnormal expression of X-linked gene(s) involved in PAH pathophysiology, and a pulmonary artery endothelial cell (PAEC) proliferative phenotype. Moreover, the pathogenic proliferative p38 mitogen-activated protein kinase/ETS transcription factor ELK1 (Elk1)/cFos signaling is mechanistically linked to the sexually dimorphic proliferative response of PAECs in PAH. Apprehending the complicated relationship between long noncoding RNA X-inactive specific transcript and X-linked genes and how this relationship integrates into a sexually dimorphic proliferation of PAECs and PAH sex paradox remain challenging. We highlight herein new findings related to how the sex chromosome complement and sex-differentiated epigenetic mechanisms to control gene expression are decisive players in the sexual dimorphism of PAH. Pharmacologic interventions in the light of the newly elucidated mechanisms are discussed.

MicroRNAs in Pulmonary Hypertension, from Pathogenesis to Diagnosis and Treatment

Pulmonary hypertension (PH) is a fatal and untreatable disease, ultimately leading to right heart failure and eventually death. microRNAs are small, non-coding endogenous RNA molecules that can regulate gene expression and influence various biological processes. Changes in microRNA expression levels contribute to various cardiovascular disorders, and microRNAs have been shown to play a critical role in PH pathogenesis. In recent years, numerous studies have explored the role of microRNAs in PH, focusing on the expression profiles of microRNAs and their signaling pathways in pulmonary artery smooth muscle cells (PASMCs) or pulmonary artery endothelial cells (PAECs), PH models, and PH patients. Moreover, certain microRNAs, such as miR-150 and miR-26a, have been identified as good candidates of diagnosis biomarkers for PH. However, there are still several challenges for microRNAs as biomarkers, including difficulty in normalization, specificity in PH, and a lack of longitudinal and big sample-sized studies. Furthermore, microRNA target drugs are potential therapeutic agents for PH treatment, which have been demonstrated in PH models and in humans. Nonetheless, synthetic microRNA mimics or antagonists are susceptible to several common defects, such as low drug efficacy, inefficient drug delivery, potential toxicity and especially, off-target effects. Therefore, finding clinically safe and effective microRNA drugs remains a great challenge, and further breakthrough is urgently needed.

Acute and chronic exercise training in patients with Class II pulmonary hypertension: effects on haemodynamics and symptoms

More than half of heart failure (HF) patients have concomitant pulmonary hypertension, impacting symptoms and prognosis. The role of exercise in this category of patients is still unclear, probably because of the lack of a clear relationship between exercise and acute and chronic pulmonary artery pressure variations and related changes in symptoms. The limited evidence on this topic is contradictory and hardly comparable due to use of different exercise programmes and pulmonary artery pressure assessment techniques. This is further compounded by different functional and structural classes of HF making definite assessments and interpretations of exercise effect on outcomes difficult. Exercise training programmes were proven beneficial in HF patients; however, the lack of data about their pulmonary haemodynamic effects prevents clear indications on the best exercise types for patients presenting secondary pulmonary hypertension and different HF categories. Indeed, some data suggest that not all HF patients have similar responses to training, leading to either beneficial or detrimental effects, depending on the HF type. Future studies, involving modern technologies such as continuous pulmonary artery pressure monitoring implantable devices, may clarify the current gaps in this field, aiming at patient‐tailored exercise training rehabilitation programmes, in order to improve clinical outcomes, quality of life, and hopefully prognosis.

Chronic Inflammation as the Underlying Mechanism of the Development of Lung Diseases in Psoriasis: A Systematic Review

Psoriasis is a systemic inflammatory disease caused by dysfunctional interactions between the innate and adaptive immune responses. The systemic inflammation in psoriasis may be associated with the development of comorbidities, including lung diseases. In this review, we aimed to provide a summary of the evidence regarding the prevalence of lung diseases in patients with psoriasis and the potential underlying mechanisms. Twenty-three articles published between March 2010 and June 2021 were selected from 195 initially identified records. The findings are discussed in terms of the prevalence of asthma, chronic obstructive pulmonary disease, interstitial lung disease, obstructive sleep apnea, pulmonary hypertension, and sarcoidosis in psoriasis. A higher prevalence of lung diseases in psoriasis has been confirmed in asthma, chronic obstructive pulmonary disease, obstructive sleep apnea, and pulmonary hypertension. These conditions are important as they are previously unrecognized causes of morbidity and mortality in psoriasis. The development of lung diseases in patients with psoriasis can be explained by several mechanisms, including common risk factors, shared immune and molecular characteristics associated with chronic inflammation, as well as other mechanisms. Understanding the prevalence of lung diseases in psoriasis and their underlying mechanisms can help implement appropriate preventative and therapeutic strategies to address respiratory diseases in patients with psoriasis.

Prolonged Inhalation Exposure to Coal Dust on Irradiated Rats and Consequences

The purposes of this study were to research immune system changes and liver and lung tissues in irradiated rats after prolonged exposure to coal dust. A study was carried out on 30 male Wistar rats that were divided into 3 groups: group I, intact animals; group II, exposure to coal dust and 0.2 Gy γ-irradiation; and group III, combined exposure to 6 Gy γ-irradiation and coal dust. The combination of a low and sublethal dose of γ-irradiation with coal dust leads to a significant change in immunity at the remote period. Particularly, the increase in radioactivity at the combined effect causes weakening of phagocytosis, and reduction in T lymphocytes by a factor of 2, immunoglobulin imbalance, and cytokine dysfunction develop secondary immune failure. During prolonged inhalation with coal dust of irradiated animals with the dose of 0.2 Gy, fibrosis and perivascular sclerosis of the bronchial wall of the lungs are formed, and perivascular fibrosis is formed in the liver. The increase in exposure dose up to 6 Gy in combination with coal, in the distant period, caused pulmonary hypertension amid hypertrophy of light arterial vessels and fibrous changes in arteriole, and destructive changes and collection necrosis develop in liver parenchyma. In the case of dust radiation synergy, the increase in doses leads to a significant immune deficiency, which occurs according to the “dose effect” principle; increases damage to animal tissues; and leads to liver tissue necrosis, pulmonary fibrosis, and pulmonary hypertension.

Epigenetic Mechanisms as Emerging Therapeutic Targets and Microfluidic Chips Application in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a disease that progress over time and is defined as an increase in pulmonary arterial pressure and pulmonary vascular resistance that frequently leads to right-ventricular (RV) failure and death. Epigenetic modifications comprising DNA methylation, histone remodeling, and noncoding RNAs (ncRNAs) have been established to govern chromatin structure and transcriptional responses in various cell types during disease development. However, dysregulation of these epigenetic mechanisms has not yet been explored in detail in the pathology of pulmonary arterial hypertension and its progression with vascular remodeling and right-heart failure (RHF). Targeting epigenetic regulators including histone methylation, acetylation, or miRNAs offers many possible candidates for drug discovery and will no doubt be a tempting area to explore for PAH therapies. This review focuses on studies in epigenetic mechanisms including the writers, the readers, and the erasers of epigenetic marks and targeting epigenetic regulators or modifiers for treatment of PAH and its complications described as RHF. Data analyses from experimental cell models and animal induced PAH models have demonstrated that significant changes in the expression levels of multiple epigenetics modifiers such as HDMs, HDACs, sirtuins (Sirt1 and Sirt3), and BRD4 correlate strongly with proliferation, apoptosis, inflammation, and fibrosis linked to the pathological vascular remodeling during PAH development. The reversible characteristics of protein methylation and acetylation can be applied for exploring small-molecule modulators such as valproic acid (HDAC inhibitor) or resveratrol (Sirt1 activator) in different preclinical models for treatment of diseases including PAH and RHF. This review also presents to the readers the application of microfluidic devices to study sex differences in PAH pathophysiology, as well as for epigenetic analysis.

Intra-Airway Gene Delivery for Pulmonary Hypertension in Rodent Models

Pulmonary arterial hypertension (PAH) is a severe and progressive cardiopulmonary disease characterized by pathological remodeling of the resistance pulmonary arteries (PA), ultimately leading to right ventricular (RV) failure and death. Animal models have been particularly useful for unraveling the pathogenesis of PAH by providing incisive experimental strategies that were impossible in human studies. Over the past decade, gene therapy has been making considerable progress as an alternative strategy for treating PAH disease. Animal models mimicking PAH disease are essential at preclinical stages for assessing the therapeutic potential of gene therapy and determining genome viral vectors transduction, safety, dosage, and localization of transgene expression. The most commonly used PAH rat models in gene therapy studies are the monocrotaline (MCT), the chronic hypoxia-Sugen 5416, and the pneumonectomy (PNT)-MCT models. Here, we provide detailed protocols for creating these preclinical rodent models of PAH commonly used to assess the efficiency of lung gene therapy in PAH.