Mendelian randomization study on causal association of TEF and circadian rhythm with pulmonary arterial hypertension.

BACKGROUND: Previous research has revealed the potential impact of circadian rhythms on pulmonary diseases; however, the connection between circadian rhythm-associated Thyrotroph Embryonic Factor (TEF) and Pulmonary Arterial Hypertension (PAH) remains unclear. We aim to assess the genetic causal relationship between TEF and PAH by utilizing two sets of genetic instrumental variables (IV) and publicly available Pulmonary Arterial Hypertension Genome-Wide Association Studies (GWAS). METHODS: Total of 23 independent TEF genetic IVs from recent MR reports and PAH GWAS including 162,962 European individuals were used to perform this two-sample MR study. Gain- and loss-of-function experiments were used to demonstrate the role of TEF in PAH. RESULTS: Our analysis revealed that as TEF levels increased genetically, there was a corresponding increase in the risk of PAH, as evidenced by IVW (OR = 1.233, 95% CI: 1.054-1.441; P = 0.00871) and weighted median (OR = 1.292, 95% CI for OR: 1.064-1.568; P = 0.00964) methods. Additionally, the up-regulation of TEF expression was associated with a significantly higher likelihood of abnormal circadian rhythm (IVW: P = 0.0024733, ß = 0.05239). However, we did not observe a significant positive correlation between circadian rhythm and PAH (IVW: P = 0.3454942, ß = 1.4980398). In addition, our in vitro experiments demonstrated that TEF is significantly overexpressed in pulmonary artery smooth muscle cells (PASMCs). And overexpression of TEF promotes PASMC viability and migratory capacity, as well as upregulates the levels of inflammatory cytokines. CONCLUSION: Our analysis suggests a causal relationship between genetically increased TEF levels and an elevated risk of both PAH and abnormal circadian rhythm. Consequently, higher TEF levels may represent a risk factor for individuals with PAH.

Unraveling the Impact of miR-146a in Pulmonary Arterial Hypertension Pathophysiology and Right Ventricular Function.

Pulmonary arterial hypertension (PAH) is a chronic disorder characterized by excessive pulmonary vascular remodeling, leading to elevated pulmonary vascular resistance and right ventricle (RV) overload and failure. MicroRNA-146a (miR-146a) promotes vascular smooth muscle cell proliferation and vascular neointimal hyperplasia, both hallmarks of PAH. This study aimed to investigate the effects of miR-146a through pharmacological or genetic inhibition on experimental PAH and RV pressure overload animal models. Additionally, we examined the overexpression of miR-146a on human pulmonary artery smooth muscle cells (hPASMCs). Here, we showed that miR-146a genic expression was increased in the lungs of patients with PAH and the plasma of monocrotaline (MCT) rats. Interestingly, genetic ablation of miR-146a improved RV hypertrophy and systolic pressures in Sugen 5415/hypoxia (SuHx) and pulmonary arterial banding (PAB) mice. Pharmacological inhibition of miR-146a improved RV remodeling in PAB-wild type mice and MCT rats, and enhanced exercise capacity in MCT rats. However, overexpression of miR-146a did not affect proliferation, migration, and apoptosis in control-hPASMCs. Our findings show that miR-146a may play a significant role in RV function and remodeling, representing a promising therapeutic target for RV hypertrophy and, consequently, PAH.

Contemporary survival outcomes of congenital systemic-to-pulmonary shunt in children with borderline pulmonary vascular resistant index compared to Eisenmenger syndrome.

Pulmonary arterial hypertension (PAH) associated with congenital heart disease (PAH-CHD) is a complication that occurs after unrepaired significant systemic-to-pulmonary shunt. Treatment options for PAH-CHD-predominantly left-to-right (L-R) shunt in children with borderline-high pulmonary vascular resistant index (PVRi) have been debated. We aimed to assess the treatment and survival of children with PAH-CHD-predominantly L-R shunt with borderline to high PVRi, using Eisenmenger syndrome (ES) for comparison. In 1995-2021, a total of 142 patients with ES and 192 children with PAH-CHD-predominantly L-R shunt were eligible for our analysis. The PVRi in ES patients was 26.7 ± 16.8 WU m2. Most patients (91%) received PAH-targeted therapy. Of the 192 children with PAH-CHD-predominantly L-R shunt, the baseline PVRi was 9.2 ± 5.8 WU m2. A total of 64 patients (33.3%) had borderline PVRi (4-8 WU m2) and 98 patients (51%) had high PVRi (> 8 WU m2). Most patients (88.5%) responded to acute pulmonary vasodilatory testing and underwent repair, with 158 undergoing defect closure and 12 having fenestrated closure. A treat-and-repair strategy was used in 33 children (17.1%). The 10- and 15-year survival rates for patients with ES were 79.3% and 72.4%, respectively, which was significantly inferior to children with borderline PVRi [97.3% and 87.8% (p = 0.02)]; and high PVRi [91.6% and 89.5% (p = 0.06)], respectively. The survival rate of children receiving treat-and-repair was slightly higher than that of ES (p = 0.16). The independent mortality risk in children with PAH-CHD-predominantly L-R shunt was persistent PAH following the defect correction (adjusted hazard ratio 5.8, 95% CI 1.7-19.9, p = 0.005).Trial registration: TCTR20200420004.

The relativity analysis of hypoxia inducible factor-1α in pulmonary arterial hypertension (ascites syndrome) in broilers: a review.

Ascites syndrome (AS) in broiler chickens, also known as pulmonary arterial hypertension (PAH), is a significant disease in the poultry industry. It is a nutritional metabolic disease that is closely associated with hypoxia-inducible factors and rapid growth. The rise in pulmonary artery pressure is a crucial characteristic of AS and is instrumental in its development. Hypoxia-inducible factor 1α (HIF-1α) is an active subunit of a key transcription factor in the oxygen-sensing pathway. HIF-1α plays a vital role in oxygen homeostasis and the development of pulmonary hypertension. Studying the effects of HIF-1α on pulmonary hypertension in humans or mammals, as well as ascites in broilers, can help us understand the pathogenesis of AS. Therefore, this review aims to (1) summarize the mechanism of HIF-1α in the development of pulmonary hypertension, (2) provide theoretical significance in explaining the mechanism of HIF-1α in the development of pulmonary arterial hypertension (ascites syndrome) in broilers, and (3) establish the correlation between HIF-1α and pulmonary arterial hypertension (ascites syndrome) in broilers. HIGHLIGHTSExplains the hypoxic mechanism of HIF-1α.Linking HIF-1α to pulmonary hypertension in broilers.Explains the role of microRNAs in pulmonary arterial hypertension in broilers.

Echocardiographic right ventricular evaluation in cardiac surgery patients undergoing mitral valve reconstruction: a single center prospective observational study.

Background: Mitral valve (MV) regurgitation (MR) is the second most frequent indication for valvular surgery in Europe. Right ventricular (RV) dysfunction is a common finding after cardiac surgery and might persist for years. The RV-function after MV surgery has been controversially discussed. We therefore aimed to evaluate early RV-performance in patients undergoing MV surgery. Methods: Between 09/2020 and 06/2022, ninety-two patients presenting with MR undergoing MV surgery were consented and prospectively included for evaluation. Echocardiographic evaluation was performed one day before surgery, one week after surgery and three months later. Primary endpoints reported RV-function changes including tricuspid annular plane systolic excursion (TAPSE), RV systolic prime (S') and fractional area change (FAC). Secondary endpoints included stability of MV repair, changes in left ventricular functions and early mortality. Results: Mean patients' age was 59.1±11.4 years. Fifty-five (59.7%) patients were male. Most of patients presented with severe (n=88; 95.7%) MR. Mean systolic pulmonary artery pressure was 35.6±15.7 mmHg. Moderate or severe pulmonary arterial hypertension (PAH) was present in 60 (65.2%) patients. Patients underwent either isolated MV surgery (n=67; 72.8%) or combined with tricuspid valve surgery (n=25; 27.2%). Minimal invasive surgery was performed in 26.1% (n=24) of the patients. Postoperative short-term follow-up at 3 months reported RV-dysfunction in 44.5% (n=41) of the patients as indicated by reductions in TAPSE & RV S' from 21.2±4.7 to 14±3.3 mm (P<0.001) and from 14.7±4.3 to 9.7±2.8 cm/s (P<0.001) respectively. The FAC reduction from 42.9%±9.6% to 42.2%±9.9% was non-significant (P=0.593) and no need for redo mitral or tricuspid valve surgery was reported. Finally, the presence and severity of preoperative PAH played significant roles for the incidence of RV dysfunction, P=0.021 and P=0.047, respectively. Minimal invasive surgical procedure significantly reduced the incidence of postoperative RV-dysfunction (P=0.013). Conclusions: Study early results report a significant reduction of RV-function after MV surgery as measured by TAPSE, & RV S', even when the FAC remains unchanged. Even though, this finding has limited prognostic implications during an uneventful surgical course.

The TREK-1 potassium channel is a potential pharmacological target for vasorelaxation in pulmonary hypertension.

BACKGROUND AND PURPOSE: Pulmonary arterial hypertension (PAH) is a progressive disease in which chronic membrane potential (Em) depolarisation of the pulmonary arterial smooth muscle cells (PASMCs) causes calcium overload, a key pathological alteration. Under resting conditions, the negative Em is mainly set by two pore domain potassium (K2P) channels, of which the TASK-1 has been extensively investigated. EXPERIMENTAL APPROACH: Ion channel currents and membrane potential of primary cultured human(h) PASMCs were measured using the voltage- and current clamp methods. Intracellular [Ca2+] was monitored using fluorescent microscopy. Pulmonary BP and vascular tone measurements were also performed ex vivo using a rat PAH model. KEY RESULTS: TREK-1 was the most abundantly expressed K2P in hPASMCs of healthy donors and idiopathic(I) PAH patients. Background K+-current was similar in hPASMCs for both groups and significantly enhanced by the TREK activator ML-335. In donor hPASMCs, siRNA silencing or pharmacological inhibition of TREK-1 caused depolarisation, reminiscent of the electrophysiological phenotype of idiopathic PAH. ML-335 hyperpolarised donor hPASMCs and normalised the Em of IPAH hPASMCs. A close link was found between TREK-1 activity and intracellular Ca2+-signalling using a channel activator, ML-335, and an inhibitor, spadin. In the rat, ML-335 relaxed isolated pre-constricted pulmonary arteries and significantly decreased pulmonary arterial pressure in the isolated perfused lung. CONCLUSIONS AND IMPLICATIONS: These data suggest that TREK-1is a key factor in Em setting and Ca2+ homeostasis of hPASMC, and therefore, essential for maintenance of a low resting pulmonary vascular tone. Thus TREK-1 may represent a new therapeutic target for PAH.

Clinical use of macitentan in the treatment of connective tissue disease-associated pulmonary arterial hypertension.

Background: Connective tissue disease (CTD) is the second most common cause of the pulmonary arterial hypertension (PAH). Currently, clinical data concerning CTD-PAH is scarce. Our study aimed to assess the efficacy and safety of macitentan in the treatment of CTD-PAH. Methods: In this retrospective study, patients diagnosed with CTD-PAH at The First Affiliated Hospital of Soochow University from April 2020 to November 2021 were included. Of the patients, 9 were switched to macitentan monotherapy whereas 23 received initial combination therapy. The mean follow-up time was 24 weeks. Six-minute walking distance (6MWD), World Health Organization functional class (WHO-FC), serum N-terminal pro-brain natriuretic peptide (NT-proBNP), and echocardiography parameters before and after medication were assessed. Adverse reactions were also recorded and compared. Results: After 24 weeks of treatment, 6MWD, NT-proBNP, systolic pulmonary artery pressure (sPAP) estimated by ultrasound, tricuspid regurgitation pressure gradient (TRPG) and tricuspid annular plane systolic excursion (TAPSE) in the macitentan monotherapy group revealed significant differences (Z=-2.67, Z=-2.67, t=6.20, t=5.60, t=-3.04, P<0.05). There were no statistically significant differences in right ventricular diameter (RVD), right atrial diameter (RAD), ascending aortic root inner diameter (AAO) and left ventricular end-diastolic diameter (LVEDd) (P>0.05). After 24 weeks of medication, the number of patients with WHO-FC grade III/IV symptoms decreased from 6 to 3, 1 to 0 respectively (P<0.05), and that of patients with WHO-FC grade I/II symptoms increased from 0 to 2, 2 to 4 respectively(P<0.05). After 24 weeks of treatment, 6MWD, NT-proBNP, LVEDd, sPAP and TRPG in the macitentan combined with sildenafil treatment group revealed statistically significant differences (Z=-4.11, Z=-3.74, Z=-3.83, t=6.88, t=6.54, P<0.001). Significant differences in RVD, RAD, and TAPSE were found (t=3.46, t=3.69, t=-3.12, P<0.05). There were no statistically significant variances in AAO between the groups (P>0.05). The number of patients with WHO-FC grade III/IV symptoms decreased from 16 to 8, 5 to 0 respectively (P<0.05), and that of patients with WHO-FC grade I/II symptoms increased from 0 to 1, 2 to 14 respectively (P<0.001). There were no statistically significant differences before and after treatment in 6MWD, NT-proBNP, RVD, RAD, AAO, LVEDd, sPAP, TRPG and TAPSE between the two groups (P>0.05). There were no statistically significant differences in alanine aminotransferase (ALT), aspartate aminotransferase (AST), serum creatinine (Scr) and hemoglobin (Hb) between 0 and 24 weeks (P>0.05). Conclusions: Exercise tolerance and cardiac function in patients with CTD-PAH were significantly improved after treatment with macitentan, which was well tolerated. Therefore, macitentan may be an effective and safe targeted drug for CTD-PAH.

Management of pulmonary arterial hypertension：before, during and after pregnancy.

Pregnancy complicated with pulmonary arterial hypertension (PAH) is a severe and dangerous condition for both the mother and the fetus. Pregnancy-specific alterations in the maternal cardiovascular system suggest that PAH in pregnancy may manifest more severe symptoms compared with those in non-pregnant patients. Although most societal guidelines recommend early termination in the case of PAH, some recent data suggests that maternal mortality among patients with PAH is lower than previously observed and suggests if a woman decides to proceed with the pregnancy, she should be counseled about the potential risks of continuing with the pregnancy. This review paper starts with a real clinical case of PAH complicating with pregnancy, then summarizes the clinical features, diagnosis, and risk stratification. Effective treatments were also clarified, including pre-conception counseling and monitoring, general and supportive care, medication and immune therapy, delivery and postpartum care, counseling on contraception and breastfeeding, maternal and fetal outcomes, and cardiac surgery. The article summarizes points of uncertainty in both laboratory and clinical practices, as well as current guidelines and clinical recommendations.

Impact of rapid sequential combination therapy on distinct haemodynamic measures in newly diagnosed pulmonary arterial hypertension.

AIMS: In pulmonary arterial hypertension (PAH), upfront combination therapy with ERA and PDE5i is associated with a reduction in morbidity and mortality events and improves standard haemodynamics, but data remain limited. Aims of this study were (i) to capture detailed haemodynamic effects of rapid sequential dual combination therapy in patients with newly diagnosed PAH; (ii) to monitor the impact of treatment initiation on clinical variables and patients' risk status, and (iii) to compare the treatment effect in patients with 'classical PAH' and 'PAH with co-morbidities'. METHODS: Fifty patients (median age 57 [42-71] years, 66% female) with newly diagnosed PAH (76% idiopathic) were treated with a PD5i/sGC-S or ERA, followed by addition of the respective other drug class within 4 weeks. All patients underwent repeat right heart catheterization (RHC) during early follow-up. RESULTS: At early repeat RHC (7 ± 2 months), there were substantial reductions in mean pulmonary artery pressure (mPAP: 52.2 ± 13.5 to 39.0 ± 10.6 mmHg; -25.3%), and pulmonary vascular resistance (PVR: 12.1 ± 5.7 to 5.8 ± 3.1 WU; -52.1%), and an increase in cardiac index (2.1 ± 0.4 to 2.7 ± 0.7 mL/min/m2; +32.2%) (all P < 0.05). Haemodynamic improvements correlated with improved clinical parameters including 6-min walking distance (336 ± 315 to 389 ± 120 m), NTproBNP levels (1.712 ± 2.024 to 506 ± 550 ng/L, both P < 0.05) and WHO-FC at 12 months, resulting in improved risk status, and were found in patients with few (n = 37) or multiple cardiovascular co-morbidities (BMI > 30 kg/m2, hypertension, diabetes, coronary artery disease [≥3]; n = 13), albeit baseline PVR in PAH patients with multiple co-morbidities was lower (9.3 ± 4.4 vs. 13.1 ± 5.9 WU) and PVR reduction less pronounced compared with those with few co-morbidities (-42.7% vs. -54.7%). However, comprehensive haemodynamic assessment considering further variables of prognostic relevance such as stroke volume index and pulmonary artery compliance showed similar improvements among the two groups (SVI: +50.0% vs. +49.2%; PAC: 91.7% vs. 100.0%). Finally, the 4-strata risk assessment approach was better able to capture treatment response as compared with other approaches, particularly in patients with co-morbidities. CONCLUSIONS: Rapid sequential combination therapy with PDE5i/sGC-S and ERA substantially ameliorates cardiopulmonary haemodynamics at early follow-up in patients without, and to a lesser extent, with cardiovascular co-morbidities. This occurs in line with improvements of clinical parameters and risk status.

The novel roles of YULINK in the migration, proliferation and glycolysis of pulmonary arterial smooth muscle cells: implications for pulmonary arterial hypertension.

BACKGROUND: Abnormal remodeling of the pulmonary vasculature, characterized by the proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs) along with dysregulated glycolysis, is a pathognomonic feature of pulmonary arterial hypertension (PAH). YULINK (MIOS, Entrez Gene: 54468), a newly identified gene, has been recently shown to possess pleiotropic physiologic functions. This study aims to determine novel roles of YULINK in the regulation of PAH-related pathogenesis, including PASMC migration, proliferation and glycolysis. RESULTS: Our results utilized two PAH-related cell models: PASMCs treated with platelet-derived growth factor (PDGF) and PASMCs harvested from monocrotaline (MCT)-induced PAH rats (PAH-PASMCs). YULINK modulation, either by knockdown or overexpression, was found to influence PASMC migration and proliferation in both models. Additionally, YULINK was implicated in glycolytic processes, impacting glucose uptake, glucose transporter 1 (GLUT1) expression, hexokinase II (HK-2) expression, and pyruvate production in PASMCs. Notably, YULINK and GLUT1 were observed to colocalize on PASMC membranes under PAH-related pathogenic conditions. Indeed, increased YULINK expression was also detected in the pulmonary artery of human PAH specimen. Furthermore, YULINK inhibition led to the suppression of platelet-derived growth factor receptor (PDGFR) and the phosphorylation of focal adhesion kinase (FAK), phosphoinositide 3-kinase (PI3K), and protein kinase B (AKT) in both cell models. These findings suggest that the effects of YULINK are potentially mediated through the PI3K-AKT signaling pathway. CONCLUSIONS: Our findings indicate that YULINK appears to play a crucial role in the migration, proliferation, and glycolysis in PASMCs and therefore positioning it as a novel promising therapeutic target for PAH.

A very rare cause of pre-capillary pulmonary hypertension: The PAMI syndrome.

We report the first known case of PAMI syndrome associated with pulmonary arterial hypertension (PAH) with a positive response to cyclophosphamide and pulmonary vasodilators. The patient's history began at 7 months with severe pancytopenia and fever. As time progressed, migrating arthritis, hepatosplenomegaly, and a growth deficit manifested without a plausible explanation. At the age of 17, worsening dyspnea led to a diagnosis of severe pre-capillary pulmonary hypertension and, after a multidisciplinary evaluation, a dual therapy with both vasoactive and immunosuppressive agents led to rapid clinical improvement. After a decade of stability, stopping sildenafil caused deterioration, reversed upon reintroduction. Thirty years after the onset of signs and symptoms, a genetic test identified the underlying condition known as PAMI syndrome. As PAMI syndrome involves intense systemic inflammation similar to PAH related to systemic lupus erythematosus (SLE), parameters and functional autonomy appropriately responded to early immunosuppressive and vasoactive therapy. PAMI syndrome, a rare autoinflammatory disease, is linked to precapillary pulmonary hypertension but the exact cause and optimal treatment approach are not fully understood, requiring further research for clarification and improved treatment options.

Epigenetic regulation of programmed cell death in hypoxia-induced pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is a severe progressive disease that may cause early right ventricular failure and eventual cardiac failure. The pathogenesis of PAH involves endothelial dysfunction, aberrant proliferation of pulmonary artery smooth muscle cells (PASMCs), and vascular fibrosis. Hypoxia has been shown to induce elevated secretion of vascular endothelial growth factor (VEGF), leading to the development of hypoxic PAH. However, the molecular mechanisms underlying hypoxic PAH remain incompletely understood. Programmed cell death (PCD) is a natural cell death and regulated by certain genes. Emerging evidence suggests that apoptotic resistance contributes to the development of PAH. Moreover, several novel types of PCD, such as autophagy, pyroptosis, and ferroptosis, have been reported to be involved in the development of PAH. Additionally, multiple diverse epigenetic mechanisms including RNA methylation, DNA methylation, histone modification, and the non-coding RNA molecule-mediated processes have been strongly linked to the development of PAH. These epigenetic modifications affect the expression of genes, which produce important changes in cellular biological processes, including PCD. Consequently, a better understanding of the PCD processes and epigenetic modification involved in PAH will provide novel, specific therapeutic strategies for diagnosis and treatment. In this review, we aim to discuss recent advances in epigenetic mechanisms and elucidate the role of epigenetic modifications in regulating PCD in hypoxia-induced PAH.

Interaction of Biochemical Processes between Chronic Obstructive Pulmonary Disease (COPD), Pulmonary Arterial Hypertension (PAH), and Coronavirus Disease 2019 (COVID-19).

Both pulmonary arterial hypertension (PAH) and chronic obstructive pulmonary disease (COPD) are risk factors for coronavirus disease 2019 (COVID-19). Patients with lung injury and altered pulmonary vascular anatomy or function are more susceptible to infections. The purpose of the study is to ascertain whether individuals with COPD or PAH are affected synergistically by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Data sources for the construction of a protein-protein interaction (PPI) network and the identification of differentially expressed genes (DEGs) included three RNA-seq datasets from the GEO database (GSE147507, GSE106986, and GSE15197). Then, relationships between miRNAs, common DEGs, and transcription factor (TF) genes were discovered. Functional analysis using Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and other databases, as well as the forecasting of antiviral medications for COPD and PAH patients infected with SARS-CoV-2, were also performed. Eleven common DEGs were found in the three datasets, and their biological functions were primarily enriched in the control of protein modification processes, particularly phosphorylation. Growth factor receptor binding reflects molecular function. KEGG analysis indicated that co-DEGs mainly activate Ras, and PI3K-Akt signaling pathways and act on focal adhesions. NFKB1 interacted with HSA-miR-942 in the TF-miRNA-DEGs synergistic regulatory network. Acetaminophen is considered an effective drug candidate. There are some connections between COPD and PAH and the development of COVID-19. This research could aid in developing COVID-19 vaccines and medication candidates that would work well as COVID-19 therapies.

Early experience with pulmonary endarterectomy in Bulgaria-case series.

Background: Pulmonary arterial hypertension (PAH) is a condition that limits the quality of life and life expectancy. The predicted mortality at 1 year is estimated at 30-40% without treatment. Of the types of PAH, chronic thromboembolic pulmonary hypertension (CTEPH) is most amenable to treatment and guidelines recommend pulmonary endarterectomy (PEA) surgery for 'operable' patients (where disease is found in the proximal pulmonary vessels). Traditionally these patients were referred to a European centre with the complexities of international travel, pre- and post-operative care, and funding. We sought to establish a national PEA programme to serve the Bulgarian population and avoid some of the problems of international healthcare. Case Description: A total of 11 patients underwent PEA in 2 cardiac centres in Bulgaria (Acibadem Hospital and Government Hospital Lozenetz Sofia). The age of patients ranged from 22 to 80. The preoperative pulmonary vascular resistance (PVR) ranged from 309 to 1,906 dynes/sec/cm-5. For the surviving patients the average PVR reduction was 615 dynes/sec/cm-5 at 6 months, the average intensive care unit (ICU) stay 6.7 days, and hospitalisation 15.2 days. Nine out of 11 patients survived to hospital discharge and 6 months follow, all with normalised PVR and exercise tolerance. Conclusions: We present our results of initial experience with PEA in Bulgaria with encouraging results. Our work shows that inter-European relationship for healthcare can be productive and offer safe treatment on local level.

Emerging biologics for the treatment of pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is a rare pulmonary vascular disorder, wherein mean systemic arterial pressure (mPAP) becomes abnormally high because of aberrant changes in various proliferative and inflammatory signalling pathways of pulmonary arterial cells. Currently used anti-PAH drugs chiefly target the vasodilatory and vasoconstrictive pathways. However, an imbalance between bone morphogenetic protein receptor type II (BMPRII) and transforming growth factor beta (TGF-ß) pathways is also implicated in PAH predisposition and pathogenesis. Compared to currently used PAH drugs, various biologics have shown promise as PAH therapeutics that elicit their therapeutic actions akin to endogenous proteins. Biologics that have thus far been explored as PAH therapeutics include monoclonal antibodies, recombinant proteins, engineered cells, and nucleic acids. Because of their similarity with naturally occurring proteins and high binding affinity, biologics are more potent and effective and produce fewer side effects when compared with small molecule drugs. However, biologics also suffer from the limitations of producing immunogenic adverse effects. This review describes various emerging and promising biologics targeting the proliferative/apoptotic and vasodilatory pathways involved in PAH pathogenesis. Here, we have discussed sotatercept, a TGF-ß ligand trap, which is reported to reverse vascular remodelling and reduce PVR with an improved 6-minute walk distance (6-MWDT). We also elaborated on other biologics including BMP9 ligand and anti-gremlin1 antibody, anti-OPG antibody, and getagozumab monoclonal antibody and cell-based therapies. Overall, recent literature suggests that biologics hold excellent promise as a safe and effective alternative to currently used PAH therapeutics.

Effect of Inhalation Profile on Delivery of Treprostinil Palmitil Inhalation Powder.

Treprostinil palmitil (TP), a prodrug of treprostinil, is being developed as an inhalation powder (TPIP) for the treatment of patients with pulmonary arterial hypertension (PAH) and pulmonary hypertension due to interstitial lung disease (PH-ILD). In ongoing human clinical trials, TPIP is administered via a commercially available high resistance (HR) RS01 capsule-based dry powder inhaler (DPI) device manufactured by Berry Global (formerly Plastiape), which utilizes the patient's inspiratory flow to provide the required energy to deagglomerate and disperse the powder for delivery to their lungs. In this study, we characterized the aerosol performance of TPIP in response to changes in inhalation profiles to model more realistic use scenarios, i.e., for reduced inspiratory volumes and with inhalation acceleration rates that differ from those described in the compendia. The emitted dose of TP for all combinations of inhalation profiles and volumes ranged narrowly between 79 and 89% for the 16 and 32 mg TPIP capsules at the 60 LPM inspiratory flow rate but was reduced to 72-76% for the 16 mg TPIP capsule under the scenarios at the 30 LPM peak inspiratory flow rate. There were no meaningful differences in the fine particle dose (FPD) at all conditions at 60 LPM with the 4 L inhalation volume. The FPD values for the 16 mg TPIP capsule ranged narrowly between 60 and 65% of the loaded dose for all inhalation ramp rates with a 4 L volume and at both extremes of ramp rates for inhalation volumes down to 1 L, while the FPD values for the 32 mg TPIP capsule ranged between 53 and 65% of the loaded dose for all inhalation ramp rates with a 4 L volume and at both extremes of ramp rates for inhalation volumes down to 1 L for the 60 LPM flow rate. At the 30 LPM peak flow rate, the FPD values for the 16 mg TPIP capsule ranged narrowly between 54 and 58% of the loaded dose at both extremes of the ramp rates for inhalation volumes down to 1 L. Based on these in vitro findings, the TPIP delivery system appears not to be affected by the changes in inspiratory flow profiles or inspiratory volumes that might be expected to occur in patients with PAH or PH associated with underlying lung conditions such as ILD.

Systemic Lupus Erythematosus and Pulmonary Hypertension.

Pulmonary Hypertension (PH) is a common manifestation in patients with Systemic Lupus Erythematosus (SLE) and varies from asymptomatic to life-threatening disease. PH can result not only from immune system dysregulation, but also from various conditions, including cardiorespiratory disorders and thromboembolic diseases. Most commonly, SLE-related PH presents with non-specific symptoms, such as progressive dyspnea on exertion, generalized fatigue and weakness and eventually dyspnea at rest. Prompt diagnosis of SLE-related PH and early identification of the underlying pathogenetic mechanisms is demanded in order to introduce targeted therapy to prevent irreversible pulmonary vascular damage. In most cases the management of PH in SLE patients is similar to idiopathic pulmonary arterial hypertension (PAH). Furthermore, specific diagnostic tools like biomarkers or screening protocols, to establish early diagnosis seem to be not available yet. Although, the survival rates for patients with SLE-related PH vary between studies, it is evident that PH presence negatively affects the survival of SLE patients.

Important Role of Endogenous Nerve Growth Factor Receptor in the Pathogenesis of Hypoxia-Induced Pulmonary Hypertension in Mice.

Pulmonary arterial hypertension (PAH) remains a disease with poor prognosis; thus, a new mechanism for PAH treatment is necessary. Circulating nerve growth factor receptor (Ngfr)-positive cells in peripheral blood mononuclear cells are associated with disease severity and the prognosis of PAH patients; however, the role of Ngfr in PAH is unknown. In this study, we evaluated the function of Ngfr using Ngfr gene-deletion (Ngfr-/-) mice. To elucidate the role of Ngfr in pulmonary hypertension (PH), we used Ngfr-/- mice that were exposed to chronic hypoxic conditions (10% O2) for 3 weeks. The development of hypoxia-induced PH was accelerated in Ngfr-/- mice compared to littermate controls. In contrast, the reconstitution of bone marrow (BM) in Ngfr-/- mice transplanted with wild-type BM cells improved PH. Notably, the exacerbation of PH in Ngfr-/- mice was accompanied by the upregulation of pulmonary vascular remodeling-related genes in lung tissue. In a hypoxia-induced PH model, Ngfr gene deletion resulted in PH exacerbation. This suggests that Ngfr may be a key molecule involved in the pathogenesis of PAH.

Soluble Guanylyl Cyclase Activators-Promising Therapeutic Option in the Pharmacotherapy of Heart Failure and Pulmonary Hypertension.

Endogenous nitric oxide (NO)-dependent vascular relaxation plays a leading role in the homeostasis of the cardiovascular, pulmonary, and vascular systems and organs, such as the kidneys, brain, and liver. The mechanism of the intracellular action of NO in blood vessels involves the stimulation of the activity of the soluble cytosolic form of guanylyl cyclase (soluble guanylyl cyclase, sGC), increasing the level of cyclic 3'-5'-guanosine monophosphate (cGMP) in smooth muscle and subsequent vasodilation. In recent years, a new group of drugs, soluble guanylyl cyclase stimulators, has found its way into clinical practice. Based on the CHEST-1 and PATENT-1 trials, riociguat was introduced into clinical practice for treating chronic thromboembolic pulmonary hypertension (CTEPH). In January 2021, the FDA approved the use of another drug, vericiguat, for the treatment of heart failure.