Pharmacotherapy for pulmonary arterial hypertension

Upregulation of eIF2α by m6A modification accelerates the proliferation of pulmonary artery smooth muscle cells in MCT-induced pulmonary arterial hypertension rats

Pulmonary arterial hypertension (PAH) is a malignant cardiovascular disease. Eukaryotic initiation factor 2α (eIF2α) plays an important role in the proliferation of pulmonary artery smooth muscle cells (PASMCs) in hypoxia-induced pulmonary hypertension (HPH) rats. However, the regulatory mechanism of eIF2α remains poorly understood in PAH rats. Here, we discover eIF2α is markedly upregulated in monocrotaline (MCT)-induced PAH rats, eIF2α can be upregulated by mRNA methylation, and upregulated eIF2α can promote PASMC proliferation in MCT-PAH rats. GSK2606414, eIF2α inhibitor, can downregulate the expression of eIF2α and alleviate PASMC proliferation in MCT-PAH rats. And we further discover the mRNA of eIF2α has a common sequence with N 6-methyladenosine (m6A) modification by bioinformatics analysis, and the expression of METTL3, WTAP, and YTHDF1 is upregulated in MCT-PAH rats. These findings suggest a potentially novel mechanism by which eIF2α is upregulated by m6A modification in MCT-PAH rats, which is involved in the pathogenesis of PAH.

Inhibitory Effect of PPARδ Agonist GW501516 on Proliferation of Hypoxia-induced Pulmonary Arterial Smooth Muscle Cells by Regulating the mTOR Pathway

OBJECTIVE

This study aimed to investigate the effects of the peroxisome proliferator-activated receptor δ (PPARδ) agonist GW501516 on the proliferation of pulmonary artery smooth muscle cells (PASMCs) induced by hypoxia, in order to search for new drugs for the treatment and prevention of pulmonary vascular remodeling.

METHODS

PASMCs were incubated with different concentrations of GW501516 (10, 30, 100 nmol/L) under the hypoxic condition. The proliferation was determined by a CCK-8 assay. The cell cycle progression was analyzed by flow cytometry. The expression of PPARδ, S phase kinase-associated protein 2 (Skp2), and cell cycle-dependent kinase inhibitor p27 was detected by Western blotting. Then PASMCs were treated with 100 nmol/ L GW501516, 100 nmol/L mammalian target of rapamycin (mTOR) inhibitor rapamycin and/or 2 µmol/L mTOR activator MHY1485 to explore the molecular mechanisms by which GW501516 reduces the proliferation of PASMCs.

RESULTS

The presented data demonstrated that hypoxia reduced the expression of PPARδ in an oxygen concentration- and time-dependent manner, and GW501516 decreased the proliferation of PASMCs induced by hypoxia by blocking the progression through the G0/G1 to S phase of the cell cycle. In accordance with these findings, GW501516 downregulated Skp2 and upregulated p27 in hypoxia-exposed PASMCs. Further experiments showed that rapamycin had similar effects as GW501516 in inhibiting cell proliferation, arresting the cell cycle, regulating the expression of Skp2 and p27, and inactivating mTOR in hypoxia-exposed PASMCs. Moreover, MHY1485 reversed all the beneficial effects of GW501516 on hypoxia-stimulated PASMCs.

CONCLUSION

GW501516 inhibited the proliferation of PASMCs induced by hypoxia through blocking the mTOR/Skp2/p27 signaling pathway.

Allicin, an Emerging Treatment for Pulmonary Arterial Hypertension: An Experimental Study

We assessed whether allicin, through its antihypertensive and antioxidant effects, relieves vascular remodeling, endothelial function, and oxidative stress (OS), thereby improving experimental pulmonary arterial hypertension (PAH). Allicin (16 mg/kg) was administered to rats with PAH (monocrotaline 60 mg/kg). Allicin encouraged body weight gain and survival rate, and medial wall thickness and the right ventricle (RV) hypertrophy were prevented. Also, angiotensin II concentrations in the lung (0.37 ± 0.01 vs. 0.47 ± 0.06 pmoles/mL, allicin and control, respectively) and plasma (0.57 ± 0.05 vs. 0.75 ± 0.064, allicin and control respectively) and the expressions of angiotensin-converting enzyme II and angiotensin II type 1 receptor in lung tissue were maintained at normal control levels with allicin. In PAH rats treated with allicin, nitric oxide (NO) (31.72 ± 1.22 and 51.4 ± 3.45 pmoles/mL), tetrahydrobiopterin (8.43 ± 0.33 and 10.14 ± 0.70 pmoles/mL), cyclic guanosine monophosphate (5.54 ± 0.42 and 5.64 ± 0.73 pmoles/mL), and Ang-(1-7) (0.88 ± 0.23 and 0.83 ± 0.056 pmoles/mL) concentrations increased in lung tissue and plasma, respectively. In contrast, dihydrobiopterin increase was prevented in both lung tissue and plasma (5.75 ± 0.3 and 5.64 ± 0.73 pmoles/mL); meanwhile, phosphodiesterase-5 was maintained at normal levels in lung tissue. OS in PAH was prevented with allicin through the increased expression of Nrf2 in the lung. Allicin prevented the lung response to hypoxia, preventing the overexpression of HIF-1α and VEGF. Allicin attenuated the vascular remodeling and RV hypertrophy in PAH through its effects on NO-dependent vasodilation, modulation of RAS, and amelioration of OS. Also, these effects could be associated with the modulation of HIF-1α and improved lung oxygenation. The global effects of allicin contribute to preventing endothelial dysfunction, remodeling of the pulmonary arteries, and RV hypertrophy, preventing heart failure, thus favoring survival. Although human studies are needed, the data suggest that, alone or in combination therapy, allicin may be an alternative in treating PAH if we consider that, similarly to current treatments, it improves lung vasodilation and increase survival. Allicin may be considered an option when there is a lack of efficacy, and where drug intolerance is observed, to enhance the efficacy of drugs, or when more than one pathogenic mechanism must be addressed.

Association Between the Pulmonary Artery Pulsatility Index and Prognosis in Pulmonary Arterial Hypertension: A Multicentre Study

Background

Risk stratification is fundamental in the management of pulmonary arterial hypertension (PAH). Pulmonary artery pulsatility index (PAPi), defined as pulmonary arterial pulse pressure divided by right atrial pressure (RAP), is a hemodynamic index shown to predict acute right ventricular (RV) dysfunction in several settings. Our objective was to test the prognostic utility of PAPi in a diverse multicentre cohort of patients with PAH.

Methods

A multicentre retrospective cohort study of consecutive adult patients with a new diagnosis of PAH on right heart catheterization between January 2016 and December 2020 was undertaken across 4 major centres in Canada. Hemodynamic data, clinical data, and outcomes were collected. The association of PAPi and other hemodynamic variables with mortality was assessed by receiver-operating characteristic curves and Cox proportional hazards modeling.

Results

We identified 590 patients with a mean age of 61.4 ± 15.5 years, with 66.3% being female. A low PAPi (defined as < 5.3) was associated with higher mortality at 1 year: 10.2% vs 5.2% (P = 0.02). In a multivariable model including age, sex, body mass index, and functional class, a low PAPi was associated with mortality at 1 year (area under the curveof 0.64 (95% confidence interval 0.55-0.74). However, high RAP (> 8 mm Hg) was similarly predictive of mortality, with an area under the curve of 0.65.

Conclusion

PAPi was associated with mortality in a large incident PAH cohort. However, the discriminative value of PAPi was not higher than that of RAP alone.

Insights into Endothelin Receptors in Pulmonary Hypertension

Pulmonary hypertension (PH) is a disease which affects the cardiopulmonary system; it is defined as a mean pulmonary artery pressure (mPAP) > 20 mmHg as measured by right heart catheterization at rest, and is caused by complex and diverse mechanisms. In response to stimuli such as hypoxia and ischemia, the expression and synthesis of endothelin (ET) increase, leading to the activation of various signaling pathways downstream of it and producing effects such as the induction of abnormal vascular proliferation during the development of the disease. This paper reviews the regulation of endothelin receptors and their pathways in normal physiological processes and disease processes, and describes the mechanistic roles of ET receptor antagonists that are currently approved and used in clinical studies. Current clinical researches on ET are focused on the development of multi-target combinations and novel delivery methods to improve efficacy and patient compliance while reducing side effects. In this review, future research directions and trends of ET targets are described, including monotherapy and precision medicine.

Adherence and Discontinuation of Disease-Specific Therapies for Pulmonary Arterial Hypertension: A Systematic Review and Meta-Analysis

BACKGROUND

In patients with pulmonary arterial hypertension (PAH), the use of disease-specific therapies (i.e., endothelin receptor antagonists, phosphodiesterase type-5 inhibitors, soluble guanylate cyclase stimulators, prostacyclins, and prostanoids) has been associated with disease improvement and decreased mortality risk. We aimed to quantify the adherence and discontinuation rates for patients prescribed PAH-specific therapies.

METHODS

We performed a systematic review via searching MEDLINE, EMBASE, and the Cochrane Library from their inception to 4 March 2022 for observational studies published in English that reported data on adherence to and persistence with PAH-targeted therapies. Random-effects meta-analysis was performed to explore average adherence and discontinuation rates.

RESULTS

In all, 14 studies involving 14,861 individuals prescribed PAH-targeted therapies were included. The overall pooled proportion of patients adherent to their PAH-targeted medications was 60.9% (95% confidence interval [CI] 52.3-69.1%). The pooled proportions of patients adherent in questionnaire-based studies and in studies using prescription/dispensing data were 52.9% (95% CI 48.9-56.9%) and 62.9% (95% CI 53.1-72.2%), respectively. The pooled proportion of patients who discontinued their PAH-targeted medications was 42.3% (95% CI 31.6-53.3). Factors reported to impact adherence included administration frequency, length of time on treatment, co-payment, and occurrence of adverse events.

CONCLUSIONS

In the real world, a considerable proportion of patients prescribed PAH-specific therapies were non-adherent or discontinued. As diverse factors may influence treatment adherence, multifaceted interventions are needed to address this trend in order to improve patient outcomes.

REGISTRATION

The systematic review protocol was registered in the PROSPERO database (CRD42022316638).

Drug-Drug Interactions in the Management of Patients With Pulmonary Arterial Hypertension

The management of pulmonary arterial hypertension (PAH) has become more complex in recent years because of increased pharmacotherapy options and longer patient survival with increasing numbers of comorbidities. As such, more opportunities exist for drug-drug interactions between PAH-targeted medications and medications potentially used to treat comorbid conditions. In this review, we provide an overview of pharmaceutical metabolism by cytochrome P450 and discuss important drug-drug interactions for the 14 Food and Drug Administration-approved medications for PAH in the nitric oxide (NO), endothelin, and prostacyclin pathways. Among the targets in the NO pathway (sildenafil, tadalafil, and riociguat), important interactions with nitrates, protease inhibitors, and other phosphodiesterase inhibitors can cause profound hypotension. In the endothelin pathway, bosentan is associated with more drug interactions via CYP3A4 inhibition; macitentan and ambrisentan have fewer interactions of note. Although the parenteral therapies in the prostacyclin pathway bypass significant liver metabolism and avoid drug interactions, selexipag and oral treprostinil may exhibit interactions with CYP2C8 inhibitors such as gemfibrozil and clopidogrel, which can raise drug levels. Finally, we provide a framework for identifying potential drug-drug interactions and avoiding errors.

Effects of oral targeted treatments in pulmonary arterial hypertension: A systematic review and meta-analysis

Background

Although pulmonary arterial hypertension (PAH) is a fatal disease, specific drugs have been used to treat PAH. These drugs predominantly target these three pathobiological pathways: Endothelin receptor antagonist (ERA), nitric oxide (NO), and prostanoids pathways. In this review, we aimed to analyze the efficacy and safety of oral targeted treatments for PAH.

Methods

The national library of medicine (MEDLINE), excerpta medica database (EMBASE), and Cochrane Central Register of Controlled Trials databases were searched. Randomized controlled trials that compared the oral targeted drugs with placebos were selected. We calculated odds ratios (ORs) with 95% confidence intervals (CIs) for variables with dichotomous outcomes, and standardized mean differences with continuous outcomes variables. Additionally, the mean of the differences for the 6-min walk distance (6MWD) was analyzed.

Results

In total, 23 studies involving 7,121 patients were included in this study. These studies show that orally PAH-specific drugs could decrease the risk of clinical worsening events, with an OR of 0.55 (p < 0.001). Furthermore, these drugs could improve exercise capacity, showing a 21.74-m increase in 6MWD (95% CI: 17.53–25.95 m) and cause a greater amelioration of functional class (OR = 0.60, 95% CI: 0.47–0.76). Additionally, subgroup analysis indicated that compared with placebo, ERAs, and drugs in the NO pathway were most effective and safe, which are associated with an improvement in exercise capacity, 6MWD, and worsening events-free survival rate.

Conclusion

Nitric oxide exhibited the most prominent clinical effect on exercise tolerance. However, in the subgroup analysis, oral targeted drugs of different pathways show applicability to different populations, which highlights the need for precise treatment in the clinical setting.

Systematic Review Registration

[https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=297946], identifier [CRD 42022297946].

Case report: Bilateral central serous chorioretinopathy-like abnormalities in a man with pulmonary arterial hypertension

Background

Pulmonary arterial hypertension (PAH) leads to progressive increases in pulmonary vascular resistance, right heart failure, and death if left untreated. Ocular complications secondary to PAH were less reported. In this study, we reported a case of bilateral visual loss and metamorphopsia in a patient with PAH, who developed central serous chorioretinopathy (CSCR)-like abnormalities and optic disc atrophy.

Case summary

A 45-year-old man presented with decreasing central vision and metamorphopsia in both eyes. He had a history of PAH and 6-year history of low-dose oral sildenafil treatment. Slit-lamp examination revealed prominent dilated and tortuous episcleral and conjunctival vessels. Ultrawide-field color picture showed retinal pigment epithelial mottling and atrophy in ring-like configurations. Ultrawide-field autofluorescence showed multiple irregular hyper-autofluorescence with a constellation-like pattern surrounding the optic nerve head and macular region. Optical coherence tomography angiography (OCTA) b-scan demonstrated CSCR-like changes. Swept-source optical coherence tomography (SS-OCT) analysis showed optic nerve atrophy with enlarged cup/disc ratio in right eye, which was confirmed with perimetry. Fluorescein angiography (FA) showed marked leakage of macula and optic nerve head with time, cystoid macular edema, early blocking with late staining of the flecks as shown in the backgrounds of infrared and autofluorescence, and mild leakage in peripheral retina. Indocyanine green angiography (ICGA) showed dilation, tortuosity and congestion of all vortex veins without obvious leakage.

Conclusion

Undertreated PAH may cause the congestion of the choroid and induce CSCR-like abnormalities.

Mixed venous oxygen tension is a crucial prognostic factor in pulmonary hypertension: a retrospective cohort study

BACKGROUND

The prognostic value of mixed venous oxygen tension (PvO2) at pulmonary hypertension diagnosis treated with selective pulmonary vasodilators remains unclear. This study sought to investigate the association of PvO2 with long-term prognosis in pulmonary arterial hypertension (PAH) and medically treated chronic thromboembolic pulmonary hypertension (CTEPH) and to identify the distinct mechanisms influencing tissue hypoxia in patients with CTEPH or PAH.

METHODS

We retrospectively analyzed data from 138 (age: 50.2 ± 16.6 years, 81.9% women) and 268 (age: 57.4 ± 13.1 years, 72.8% women) patients with PAH and CTEPH, respectively, diagnosed at our institution from 1983 to 2018. We analyzed the survival rates of patients with/without tissue hypoxia (PvO2 < 35 mmHg) and identified their prognostic factors based on the pulmonary hypertension risk stratification guidelines.

RESULTS

Survival was significantly poorer in patients with tissue hypoxia than in those without it for PAH (P = 0.001) and CTEPH (P = 0.017) treated with selective pulmonary vasodilators. In patients with PAH, PvO2 more strongly correlated with prognosis than other hemodynamic prognostic factors regardless of selective pulmonary vasodilators usage. PvO2 was the only significant prognostic factor in patients with CTEPH treated with pulmonary hypertension medication. Patients with CTEPH experiencing tissue hypoxia exhibited significantly poorer survival than those in the intervention group (P < 0.001). PvO2 more strongly correlated with the cardiac index (CI) than the alveolar-arterial oxygen gradient (A-aDO2) in PAH; whereas in CTEPH, PvO2 was more strongly correlated with A-aDO2 than with CI.

CONCLUSIONS

PvO2 may represent a crucial prognostic factor for pulmonary hypertension. The prognostic impact of tissue hypoxia affects different aspects of PAH and CTEPH, thereby reflecting their distinct pathogenesis.

AMPK and the Challenge of Treating Hypoxic Pulmonary Hypertension

Hypoxic pulmonary hypertension (HPH) is characterized by sustained elevation of pulmonary artery pressure produced by vasoconstriction and hyperproliferative remodeling of the pulmonary artery and subsequent right ventricular hypertrophy (RVH). The search for therapeutic targets for cardiovascular pathophysiology has extended in many directions. However, studies focused on mitigating high-altitude pulmonary hypertension (HAPH) have been rare. Because AMP-activated protein kinase (AMPK) is involved in cardiovascular and metabolic pathology, AMPK is often studied as a potential therapeutic target. AMPK is best characterized as a sensor of cellular energy that can also restore cellular metabolic homeostasis. However, AMPK has been implicated in other pathways with vasculoprotective effects. Notably, cellular metabolic stress increases the intracellular ADP/ATP or AMP/ATP ratio, and AMPK activation restores ATP levels by activating energy-producing catabolic pathways and inhibiting energy-consuming anabolic pathways, such as cell growth and proliferation pathways, promoting cardiovascular protection. Thus, AMPK activation plays an important role in antiproliferative, antihypertrophic and antioxidant pathways in the pulmonary artery in HPH. However, AMPK plays contradictory roles in promoting HPH development. This review describes the main findings related to AMPK participation in HPH and its potential as a therapeutic target. It also extrapolates known AMPK functions to discuss the less-studied HAPH context.

Prospective clinical assessment of patients with pulmonary arterial hypertension switched from bosentan to macitentan (POTENT)

Even though pulmonary arterial hypertension (PAH) remains an incurable disease, the combination of PAH‐specific therapies allowed evolving from symptom‐based strategies to others aiming to move patients to low‐risk conditions. Endothelin‐1 (ET‐1) receptor antagonists emerged as specific‐PAH drugs that can be used in combination with other specific therapies. This work aimed to perform a prospective clinical assessment of patients with PAH that switched from bosentan to macitentan (POTENT), due to inadequate response. POTENT is a prospective, open‐label, single‐arm, uncontrolled study including PAH patients from our ongoing SAUDIPH registry. It enrolled 50 PAH patients divided as follows: idiopathic/heritable pulmonary arterial hypertension (I/HPAH); n = 24; PAH associated with congenital heart disease, n = 19; PAH associated with connective tissue diseases, n = 5; and pulmonary veno‐occlusive disease and/or pulmonary capillary haemangiomatosis (PVOD/PCH), n = 2. At baseline, most patients were in World Health Organization Functional Class (WHO FC) II/III (52.0%). After switching to macitentan, patients were more likely to be in WHO FC I/II (78%) and 22% of the overall cohort moved to a lower risk condition, with three low risk stratification parameters. Mean 6‐min walking distance increased about 34 m after 12 months, with a significant mean change over time (12.63 ± 11.69 at month 3 vs. 40.75 ± 12.57 at month 12, p = 0.002). Most haemodynamic parameters decreased over time, with corresponding negative mean changes (p < 0.001). The safety of macitentan was confirmed by the absence of anaemia and liver injury; clinical worsening was observed only in a small group of patients. In general, macitentan might be a valid alternative to bosentan in PAH stable patients on combination therapy with insufficient clinical response, and presenting intermediate and high‐risk parameters. We anticipate that studying this strategy in PAH subgroups would further clarify its potential and limitations.

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.

Safety, Tolerability, and Pharmacokinetics of Treprostinil Palmitil Inhalation Powder for Pulmonary Hypertension: A Phase 1, Randomized, Double-Blind, Single- and Multiple-Dose Study

INTRODUCTION

Treprostinil is a prostacyclin vasodilator widely used for the treatment of pulmonary arterial hypertension (PAH) and, in its inhaled form, for pulmonary hypertension associated with interstitial lung disease (PH-ILD). Treprostinil palmitil inhalation powder (TPIP) is a dry powder formulation of treprostinil palmitil (TP), an ester prodrug of treprostinil. TPIP is designed to provide sustained release of treprostinil in the lung over a prolonged period, potentially enabling a once-daily (QD) dosing regimen and significantly higher tolerated doses compared with currently available treprostinil formulations. This phase 1 study assessed the safety, tolerability, and pharmacokinetics of TP and treprostinil following single and multiple QD administrations of TPIP in healthy volunteers.

METHODS

Healthy adults (aged 18-45 years) were randomized to receive single or multiple QD inhalation doses of TPIP. Participants in the single-dose phase received TPIP 112.5, 225, 450, or 675 µg (n = 6/dose) or placebo (n = 2). Participants in the multiple-dose phase received TPIP 225 µg QD for 7 days (n = 6), 112.5 µg QD for 4 days followed by 225 µg QD for 3 days (n = 6), or placebo for 7 days (n = 4).

RESULTS

Overall, 41 of 42 participants (97.6%) completed the study. In the single-dose phase, 70.8% (n = 17/24) of TPIP-treated participants experienced a treatment-emergent adverse event (TEAE) vs 0% (n = 0/2) of placebo-treated participants; the most common TEAEs (≥ 20%) were cough (45.8%), dizziness (29.2%), and throat irritation (20.8%). In the multiple-dose phase, 83.3% (n = 10/12) of TPIP-treated participants experienced a TEAE vs 50.0% of placebo-treated participants (n = 2/4); the most common TEAEs were cough (58.3% TPIP vs 50.0% placebo), headache (50.0% vs 0%), nausea (33.3% vs 0%), chest discomfort (33.3% vs 0%), and dizziness (25.0% vs 0%). Most TEAEs were mild; only seven patients experienced a moderate TEAE, and no severe or serious TEAEs occurred. In the multiple-dose phase, participants whose doses were titrated from TPIP 112.5 µg QD to 225 µg QD experienced fewer TEAEs than those who received 225 µg QD at treatment initiation (66.7% vs 100.0%), and all TEAEs with dose titration were mild. After a single dose of TPIP, treprostinil elimination t_1/2 was 8.67-11.6 h and exposure was dose proportional, with mean (CV%) C_max 78.4-717 pg/mL (38.6-72.9%) and AUC_0-∞ 1090-5480 pg·h/mL (11.5-30.0%). At steady state (TPIP 225 µg), the mean (CV%) of C_max, C_min, and AUC_τ were 193-228 pg/mL (32.9-46.4%), 17.6-22.8 ng/mL (43.7-64.4%), and 1680-1820 pg·h/mL (28.7-36.6%), respectively. The elimination t_1/2 was 6.84-8.82 h after repeat dosing. No steady-state accumulation was observed. Plasma concentrations of TP were below the limit of quantification (100 pg/mL) at all time points measured.

CONCLUSION

TPIP was well tolerated at the doses tested, and dose titration improved tolerability. Treprostinil pharmacokinetics were linear and supportive of a QD treatment regimen. These results support further development of TPIP in patients with PAH and PH-ILD.

Efficacy and safety of selexipag, an oral prostacyclin receptor agonist for the treatment of pulmonary hypertension: A meta-analysis

BACKGROUND AND OBJECTIVE

This meta-analysis was performed to evaluate the effect and safety of selexipag in the treatment of pulmonary hypertension and to explore the effect of selexipag on cardiac function indexes in PAH patients.

METHODS

Electronic databases, including the Cochrane Library, EMBASE, and PubMed databases, were searched. Endnote software X9 was used for study selection, and the Cochrane Risk of Bias Tool was used for literature screening and quality assessment. Data analysis was performed using RevMan 5.3 software, and GRADE was used to assess the evidence level.

RESULTS

Ten studies were finally selected in accordance with the standard. A total of 10 papers were included. A total of 1322 patients were included, including 723 in the trial group and 599 in the control group. Patients with PAH treated with selexipag were included in the trial group, and patients with PAH treated with placebo were included in the control group. The results of the study showed that selexipag was effective in reducing mortality in patients (WMD=0.70, 95% CI: 0.53-0.94, P = 0.02). Selexipag effectively increased the 6-min walk distance (WMD=33.79, 95% CI: 2.69-64.90, P=0.03). Selexipag also effectively increased the 6-min distance between baseline and follow-up (WMD = 15.28, 95% CI: 7.76-22.80, P < 0.0001). Selexipag effectively reduced PVR (WMD = -230.96, 95% CI: 445.94 to -15.97, P = 0.04). Selexipag significantly reduced PVR between baseline and follow-up (WMD = -139.62, 95% CI: 215.32 to -63.91, P = 0.0003). The adverse reactions of selexipag were mild with headache, diarrhea and nausea reported as the main symptoms.

CONCLUSION

Selexipag is a new drug with mild adverse reactions and is safe for the treatment of PAH. This drug significantly prolongs the level of 6MWD in PAH patients, reduces the fatality rate, improves WHO FC and reduces PVR. The effects of this drug on CI, mPAP, MRAP, SvO₂ and other indicators still need to be further confirmed.

PROSPERO REGISTRATION

CRD42021245557.

[Triple combination therapy with macitentan, riociguat, and selexipag in a patient with idiopathic pulmonary arterial hypertension (functional class III)]

The article presents a clinical case of successful triple combination therapy in a female patient with functional class III idiopathic pulmonary arterial hypertension. Supplementing the previous macitentan and riociguat treatment with selexipag reduced the severity of clinical manifestations of pulmonary hypertension. Also, the treatment efficacy was demonstrated by improvement of laboratory and instrumental indexes. Time-related changes were evaluated at 3 months after initiation of the selexipag treatment.

Schistosome-Associated Pulmonary Arterial Hypertension: A Review Emphasizing Pathogenesis

Schistosomiasis, especially due to Schistosoma mansoni, is a well-recognized cause of pulmonary arterial hypertension (PAH). The high prevalence of this helminthiasis makes schistosome-related PAH (Sch-PAH) one of the most common causes of this disorder worldwide. The pathogenic mechanisms underlying Sch-PAH remain largely unknown. Available evidence suggests that schistosome eggs reach the lung via portocaval shunts formed as a consequence of portal hypertension due to hepatosplenic schistosomiasis. Once deposited into the lungs, the eggs elicit an immune response resulting in periovular granuloma formation. Immune mediators drive transforming growth factor-β (TGF-β) release, which gives rise to pulmonary vascular inflammation with subsequent remodeling and development of angiomatoid and plexiform lesions. These mechanisms elicited by the eggs seem to become autonomous and the vascular lesions progress independently of the antigen. Portopulmonary hypertension, which pathogenesis is still uncertain, may also play a role in the genesis of Sch-PAH. Recently, there have been substantial advances in the diagnosis and treatment of PAH, but it remains a difficult condition to recognize and manage, and patients still die prematurely from right-heart failure. Echocardiography is used for screening, and the formal diagnosis requires right-heart catheterization. The experience in treating Sch-PAH is largely limited to the phosphodiesterase type 5 inhibitors, with evidence suggesting that these vasodilators improve symptoms and may also improve survival. Considering the great deal of uncertainty about Sch-PAH pathogenesis, course, and treatment, the aim of this review is to summarize current knowledge on this condition emphasizing its pathogenesis.

Early combination of pulmonary vasodilators prevents chronic kidney disease progression in connective tissue disease-associated pulmonary hypertension

AIM

Pulmonary hypertension (PH) and chronic kidney disease (CKD) are interdependent for their development and exacerbation. We evaluated the effect of PH on CKD progression in patients with connective tissue disease (CTD)-associated PH.

METHODS

We reviewed consecutive patients with CTD who were diagnosed with PH with right heart catheter (RHC) examinations in our hospital. Patients were divided into 2 groups according to the use of vasodilators: monotherapy or combination therapy. We further divided the patients with combination therapy into early and non-early combination groups. Early combination was defined as the addition of the second vasodilator within 1 month after starting the first drug. The clinical course of hemodynamics and CKD progression were compared.

RESULTS

Thirty-eight patients were included in the analysis: 10 were treated with monotherapy and 28 with combination therapy (14 with early and 14 with non-early). At baseline, patients who received combination therapy had a significantly higher mean pulmonary arterial pressure with RHC and a higher right ventricular systolic pressure (RVSP) with echocardiography (P = .04) and showed a greater improvement in RVSP after treatment than those who underwent monotherapy. The incidence of CKD progression was significantly lower in patients who received combination therapy than in those who received monotherapy (P = .05). Among patients who received combination therapy, the early combination group had a lower incidence of CKD progression than the non-early combination group (P = .03).

CONCLUSIONS

Early combination therapy is associated with a lower incidence of CKD progression in patients with CTD-associated PH.

Cardiovascular Disease Complicating COVID-19 in the Elderly

SARS-CoV-2, a single-stranded RNA coronavirus, causes an illness known as coronavirus disease 2019 (COVID-19). The highly transmissible virus gains entry into human cells primarily by the binding of its spike protein to the angiotensin-converting enzyme 2 receptor, which is expressed not only in lung tissue but also in cardiac myocytes and the vascular endothelium. Cardiovascular complications are frequent in patients with COVID-19 and may be a result of viral-associated systemic and cardiac inflammation or may arise from a virus-induced hypercoagulable state. This prothrombotic state is marked by endothelial dysfunction and platelet activation in both macrovasculature and microvasculature. In patients with subclinical atherosclerosis, COVID-19 may incite atherosclerotic plaque disruption and coronary thrombosis. Hypertension and obesity are common comorbidities in COVID-19 patients that may significantly raise the risk of mortality. Sedentary behaviors, poor diet, and increased use of tobacco and alcohol, associated with prolonged stay-at-home restrictions, may promote thrombosis, while depressed mood due to social isolation can exacerbate poor self-care. Telehealth interventions via smartphone applications and other technologies that document nutrition and offer exercise programs and social connections can be used to mitigate some of the potential damage to heart health.

Population Pharmacokinetics of Tadalafil in Pediatric Patients with Pulmonary Arterial Hypertension: A Combined Adult/Pediatric Model

BACKGROUND

Tadalafil 40 mg once daily is approved for adult patients with pulmonary arterial hypertension (PAH). To investigate and potentially fulfill an unmet need in pediatric patients with PAH, pharmacokinetic (PK) data were explored in a pediatric phase Ib/II study and pooled with prior phase III (pulmonary arterial hypertension and response to tadalafil [PHIRST-1]) adult data to develop the first population PK model for tadalafil in pediatric patients with PAH.

METHODS

H6D-MC-LVIG (NCT01484431) was an open-label, multicenter, multiple ascending dose study in pediatric patients with PAH, while PHIRST-1 was a phase III, multicenter, randomized, double-blind, placebo-controlled, parallel design study in adults with PAH who received one of five treatments (tadalafil 2.5, 10, 20, or 40 mg, or placebo orally, once daily). PK data from the studies were pooled to develop a pediatric population PK model for tadalafil that characterized relationships among dose, exposure, and the effects of covariates with an aim to develop a population PK model that could simulate concentration-time profiles and assess exposure-matched dosing strategies in a pediatric PAH population.

RESULTS

In line with the observed data, modeling and simulation demonstrated that the doses studied in the pediatric population produced area under the concentration-time curves (AUCs) within the range of those associated with improved exercise ability in adults with PAH. The analyses included 1430 observations from 305 adult patients (PHIRST-1: 69 males and 236 females, 1102 observations) and 19 pediatric patients (LVIG: 6 males and 13 females, 328 observations) who received tadalafil once daily at different dose levels. The best-fit base model retained an effect of weight on apparent volume of distribution (V/F), fixed to the allometric scaling value of 1, and did not include an effect of weight on apparent clearance (CL/F). Other covariate effects were that bosentan increased CL/F, V/F decreased with decreasing body weight, and bioavailability (F) decreased with increasing dose and decreasing age. The PK model reliably predicted the observed concentrations and overall variability evident from the overlap of the individual observed concentrations with the distributions of simulated concentrations.

CONCLUSIONS

A one-compartment model parameterized in terms of F, absorption rate constant, CL/F, and V/F described the data well. The model demonstrated that plasma tadalafil concentrations in pediatric patients aged 2 to < 18 years were similar to those in adults at similar doses, and confirmed that dosing of 40 mg once daily in pediatric patients with a bodyweight ≥ 40 kg, and a dose of 20 mg once daily in patients with a body weight < 40 kg and aged ≥ 2 years are suitable for phase III evaluation.

TRIAL REGISTRATION NUMBER (DATE OF REGISTRATION)

LVIG: ClinicalTrials.gov identifier: NCT01484431 (2 December 2011). PHIRST-1: ClinicalTrials.gov identifier: NCT00125918 (2 August 2005).

Inhibition of Phosphodiesterase 3A by Cilostazol Dampens Proinflammatory Platelet Functions

OBJECTIVE

platelets possess not only haemostatic but also inflammatory properties, which combined are thought to play a detrimental role in thromboinflammatory diseases such as acute coronary syndromes and stroke. Phosphodiesterase (PDE) 3 and -5 inhibitors have demonstrated efficacy in secondary prevention of arterial thrombosis, partially mediated by their antiplatelet action. Yet it is unclear whether such inhibitors also affect platelets' inflammatory functions. Here, we aimed to examine the effect of the PDE3A inhibitor cilostazol and the PDE5 inhibitor tadalafil on platelet function in various aspects of thromboinflammation. Approach and results: cilostazol, but not tadalafil, delayed ex vivo platelet-dependent fibrin formation under whole blood flow over type I collagen at 1000 s-1. Similar results were obtained with blood from Pde3a deficient mice, indicating that cilostazol effects are mediated via PDE3A. Interestingly, cilostazol specifically reduced the release of phosphatidylserine-positive extracellular vesicles (EVs) from human platelets while not affecting total EV release. Both cilostazol and tadalafil reduced the interaction of human platelets with inflamed endothelium under arterial flow and the release of the chemokines CCL5 and CXCL4 from platelets. Moreover, cilostazol, but not tadalafil, reduced monocyte recruitment and platelet-monocyte interaction in vitro.

CONCLUSIONS

this study demonstrated yet unrecognised roles for platelet PDE3A and platelet PDE5 in platelet procoagulant and proinflammatory responses.

Emodin inhibits viability, proliferation and promotes apoptosis of hypoxic human pulmonary artery smooth muscle cells via targeting miR-244-5p/DEGS1 axis

OBJECTIVE

This study aimed to determine the effects of emodin on the viability, proliferation and apoptosis of human pulmonary artery smooth muscle cells (PASMCs) under hypoxia and to explore the underling molecular mechanisms.

METHODS

PASMCs were cultured in a hypoxic environment (1% oxygen) and then treated with emodin. Cell viability, proliferation and apoptosis were evaluated using CCK-8 assay, EdU staining assay, western blot and Mito-tracker red CMXRos and Annexin V-FITC apoptosis detection assay. The microRNA (miRNA)/mRNA and protein expression levels were assessed by quantitative real-time PCR and western blotting, respectively. Based on transcriptomics and proteomics were used to identify potential signaling pathways. Luciferase reporter assay was utilized to examine the interaction between miR-244-5p and DEGS1.

RESULTS

Emodin at 40 and 160 µM concentration-dependently suppressed cell viability, proliferation and migration, but enhanced cell apoptosis of PASMCs under hypoxia. Transcriptomic and proteomic analysis revealed that emodin could attenuate the activity of PI3K/Akt signaling in PASMCs under hypoxia. In addition, delta 4-desaturase, sphingolipid 1 (DEGS1) was found to be a direct target of miR-244-5p. Emodin could significantly up-regulated miR-244-5p expression and down-regulated DEGS1 expression in PASMCs under hypoxia. Furthermore, emodin-mediated effects on cell viability, migration, apoptosis and PI3K/Akt signaling activity of PASMCs under hypoxia were significantly attenuated by miR-244-5p knockdown.

CONCLUSIONS

Our results indicated that emodin suppressed cell viability, proliferation and migration, promoted cell apoptosis of PASMCs under hypoxia via modulating miR-244-5p-mediated DEGS1/PI3K/Akt signaling pathway. MiR-244-5p/DEGS1 axis was initially investigated in this current study, which is expected to further the understanding of the etiology of pulmonary arterial hypertension.

ROCK Inhibition as Potential Target for Treatment of Pulmonary Hypertension

Pulmonary hypertension (PH) is a cardiovascular disease caused by extensive vascular remodeling in the lungs, which ultimately leads to death in consequence of right ventricle (RV) failure. While current drugs for PH therapy address the sustained vasoconstriction, no agent effectively targets vascular cell proliferation and tissue inflammation. Rho-associated protein kinases (ROCKs) emerged in the last few decades as promising targets for PH therapy, since ROCK inhibitors demonstrated significant anti-remodeling and anti-inflammatory effects. In this review, current aspects of ROCK inhibition therapy are discussed in relation to the treatment of PH and RV dysfunction, from cell biology to preclinical and clinical studies.

Repurposing of the PDE5 Inhibitor Sildenafil for the Treatment of Persistent Pulmonary Hypertension in Neonates

Nitric oxide (NO), an important endogenous signaling molecule released from vascular endothelial cells and nerves, activates the enzyme soluble guanylate cyclase to catalyze the production of cyclic guanosine monophosphate (cGMP) from guanosine triphosphate. cGMP, in turn, activates protein kinase G to phosphorylate a range of effector proteins in smooth muscle cells that reduce intracellular Ca²⁺ levels to inhibit both contractility and proliferation. The enzyme phosphodiesterase type 5 (PDE5) curtails the actions of cGMP by hydrolyzing it into inactive 5'-GMP. Small molecule PDE5 inhibitors (PDE5is), such as sildenafil, prolong the availability of cGMP and therefore, enhance NO-mediated signaling. PDE5is are the first-line treatment for erectile dysfunction but are also now approved for the treatment of pulmonary arterial hypertension (PAH) in adults. Persistent pulmonary hypertension in neonates (PPHN) is currently treated with inhaled NO, but this is an expensive option and around 1/3 of newborns are unresponsive, resulting in the need for alternative approaches. Here the development, chemistry and pharmacology of PDE5is, the use of sildenafil for erectile dysfunction and PAH, are summarized and then current evidence for the utility of further repurposing of sildenafil, as a treatment for PPHN, is critically reviewed.

CCR7 and its related molecules may be potential biomarkers of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a chronic progressive cardiovascular disease characterized by vascular remodeling and leading to right‐heart failure. The purpose of this research was to further study the pathogenesis of PAH and to detect potential prognostic signatures. Differentially expressed genes (DEGs) selected from GSE38267 were mostly enriched in inflammation‐related pathways, suggesting inflammation may be involved in the occurrence and development of PAH. Through the prediction and verification of related miRNAs and long noncoding RNAs using online databases and Gene Expression Omnibus (GEO) datasets, CCR7 and its related molecules, including hsa‐let‐7e‐5p and SNHG12, were identified as possible targets. The expression levels of CCR7, hsa‐let‐7e‐5p and SNHG12 were then verified by quantitative RT‐PCR in vivo and in vitro. Further study showed that silencing of SNHG12 decreased the expression of CCR7 under hypoxia treatment in vitro. Dual‐luciferase reporter assays were used to verify the relationship between hsa‐let‐7e‐5p and SNHG12. Collectively, our research reveals that a long noncoding RNA–miRNA–mRNA interaction network may be involved in the pathogenesis of PAH and suggests SNHG12, hsa‐let‐7e‐5p and CCR7 as potential biomarkers for PAH.

TRIM32 inhibits the proliferation and migration of pulmonary artery smooth muscle cells through the inactivation of PI3K/Akt pathway in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a progressive and fetal cardiovascular disease. Tripartite motif 32 (TRIM32) is a member of TRIM family that has been found to be involved in cardiovascular disease. However, the role of TRIM32 in PAH remains unclear. Here we investigated the effects of TRIM32 on hypoxia-induced pulmonary artery smooth muscle cells (PASMCs) in vitro. Our results showed that TRIM32 protein level in the plasma samples from PAH patients was decreased as compared with healthy volunteers. Exposure to hypoxia condition caused a significant decrease in TRIM32 expression in PASMCs. Overexpression of TRIM32 inhibited hypoxia-induced proliferation and migration of PASMCs. TRIM32 overexpression elevated the increased apoptotic rate and caspase-3 activity in hypoxia-induced PASMCs. Moreover, overexpression of TRIM32 reversed hypoxia-induced down-regulation of myocardin, SM 22 and calponin, as well as up-regulation of osteopontin (OPN). Whereas, TRIM32 knockdown shwed the opposite effect. Furthermore, overexpression of TRIM32 inhibited hypoxia-induced activation of PI3K/Akt with decreased phosphorylated level of PI3K and Akt. Additionally, activation of PI3K/Akt by IGF-1 treatment reversed the effects of TRIM32 on hypoxia-induced PASMCs. In conclusion, these findings indicated that TRIM32 was involved in the development of PAH through regulating the proliferation, migration, apoptosis and dedifferentiation of PASMCs, which might be mediated by the PI3K/Akt signaling pathway. Thus, TRIM32 might be a potential target for PAH treatment.

Parenteral prostanoids for severe Group 3 pulmonary hypertension with right ventricular dysfunction

Background

Group 3 pulmonary hypertension (PH) is a common complication in patients with lung diseases but there are currently no FDA-approved therapies. The data is conflicting, but a few small studies suggest potential benefits in using Group 1 PH therapies in these patients, particularly in severe PH with right ventricular (RV) dysfunction.

Methods

A retrospective cohort study of patients with severe Group 3 PH with RV dysfunction who received parenteral prostanoids from 2007–2018 at our institution was undertaken. Severe PH was defined as mean pulmonary arterial pressure (mPAP) ≥35 mmHg or mPAP 25–34 with cardiac index (CI) <2.4 L/min/m². Routine prognostic studies including N-terminal prohormone of brain natriuretic peptide (NT-proBNP), 6-minute walk distance (6MWD), WHO Functional Class assessment, oxygen requirement, arterial oxygen saturation, right ventricular systolic pressure (RVSP) and right heart catheterization (RHC) pressures, were obtained before initiation of parenteral therapy and at first clinical follow-up.

Results

Nine patients were included. Five were female (55.6%) with a median [interquartile range (IQR)] of 69 [54–71] years. Median CI was 1.8 (1.6–2.4) L/min/m² and median pulmonary vascular resistance (PVR) was 14.7 (10.7–17.1) Wood units (WU). We found no statistically significant improvement in NT-proBNP levels, exercise capacity, or functional class. Resting oxygen requirement worsened from 4 to 6 L/min (P=0.04) and exertional oxygen saturation nadir worsened from 90% to 83% (P=0.01) despite the increase in FiO₂ with exertion. Overall results were heterogenous: several patients demonstrated clinical stabilization, with two undergoing lung transplantation and one showing long-term stability with medical therapy. Symptoms remained severe for most: three patients discontinued prostanoid therapy, choosing to pursue hospice care.

Conclusions

We found no statistically significant improvement in NT-proBNP levels, exercise capacity, or functional class, while oxygen requirement at rest and oxygen saturation during exertion significantly worsened. Our results suggest that parenteral prostanoids should not generally be considered in the treatment of Group 3 PH patients.

Ligustrazine Suppresses Platelet-Derived Growth Factor-BB-Induced Pulmonary Artery Smooth Muscle Cell Proliferation and Inflammation by Regulating the PI3K/AKT Signaling Pathway

Pulmonary arterial hypertension (PAH) is a serious pulmonary vascular disease. Excessive proliferation of pulmonary artery smooth muscle cells (PASMCs) plays an important role in the course of this disease. Ligustrazine is an alkaloid monomer extracted from the rhizome of the herb Ligusticum chuanxiong. It is often used to treat cardiovascular diseases, but its effect on PAH has rarely been reported. This study aims to explore the protective effect and mechanism of ligustrazine on PAH. In the in vivo experiment, monocrotaline (MCT) was used to induce PAH in rats, and then ligustrazine (40, 80, 160 mg/kg/day) or sildenafil (25 mg/kg/day) was administered. Four weeks later, hemodynamic changes, right ventricular hypertrophy index, lung morphological characteristics, inflammatory factors, phosphoinositide 3-kinase (PI3K), and AKT expression were evaluated. In addition, primary rat PASMCs were extracted by the tissue adhesion method, a proliferation model was established with platelet-derived growth factor-BB (PDGF-BB), and the cells were treated with ligustrazine to investigate its effects on cell proliferation, inflammation, and cell cycle distribution. The results indicate that ligustrazine can markedly alleviate right ventricular systolic pressure, right ventricular hypertrophy, pulmonary vascular remodeling, and inflammation caused by MCT, and that it decreased PI3K and AKT phosphorylation expression. Moreover, ligustrazine can inhibit the proliferation and inflammation of PASMCs and arrest the progression of G0/G1 to S phase through the PI3K/AKT signaling pathway. Therefore, we conclude that ligustrazine may inhibit the proliferation and inflammation of PASMCs by regulating the activation of the PI3K/AKT signaling pathway, thereby attenuating MCT-induced PAH in rats. Collectively, these findings suggest that ligustrazine may be a promising therapeutic for PAH.

The Nitric Oxide Pathway in Pulmonary Arterial Hypertension: Pathomechanism, Biomarkers and Drug Targets

The altered Nitric Oxide (NO) pathway in the pulmonary endothelium leads to increased vascular smooth muscle tone and vascular remodelling, and thus contributes to the development and progression of pulmonary arterial hypertension (PAH). The pulmonary NO signalling is abrogated by the decreased expression and dysfunction of the endothelial NO synthase (eNOS) and the accumulation of factors blocking eNOS functionality. The NO deficiency of the pulmonary vasculature can be assessed by detecting nitric oxide in the exhaled breath or measuring the degradation products of NO (nitrite, nitrate, S-nitrosothiol) in blood or urine. These non-invasive biomarkers might show the potential to correlate with changes in pulmonary haemodynamics and predict response to therapies. Current pharmacological therapies aim to stimulate pulmonary NO signalling by suppressing the degradation of NO (phosphodiesterase- 5 inhibitors) or increasing the formation of the endothelial cyclic guanosine monophosphate, which mediates the downstream effects of the pathway (soluble guanylate cyclase sensitizers). Recent data support that nitrite compounds and dietary supplements rich in nitrate might increase pulmonary NO availability and lessen vascular resistance. This review summarizes current knowledge on the involvement of the NO pathway in the pathomechanism of PAH, explores novel and easy-to-detect biomarkers of the pulmonary NO.

The progression of pulmonary arterial hypertension induced by monocrotaline is characterized by lung nitrosative and oxidative stress, and impaired pulmonary artery reactivity

The time-course of pulmonary arterial hypertension in the monocrotaline (MCT) model was investigated. Male rats were divided into two groups: MCT (received a 60 mg/kg i.p. injection) and control (received saline). The MCT and control groups were further divided into three cohorts, based on the follow-up interval: 1, 2, and 3 weeks. Right ventricle (RV) catheterization was performed and RV hypertrophy (RVH) was estimated. The lungs were used for biochemical, histological, molecular, and immunohistochemical analysis, while pulmonary artery rings were used for vascular reactivity. MCT promoted lung perivascular edema, inflammatory cells exudation, greater neutrophils and lymphocytes profile, and arteriolar wall thickness, compared to CTR group. Increases in pulmonary artery pressure and in RVH were observed in the MCT 2- and 3-week groups. The first week was marked by the presence of nitrosative stress (50% moderate and 33% accentuated staining by nitrotyrosine). These alterations lead to an adaptation of NO production by NO synthase activity after 2 weeks. Oxidative stress was evident in the third week, probably by an imbalance between endothelin-1 receptors, resulting in extracellular matrix remodeling, endothelial dysfunction, and RVH. Also, it was found a reduced pulmonary arterial vasodilatory response to acetylcholine after 2 (55%) and 3 (45%) weeks in MCT groups. The relevance of this study is precisely to show that nitrosative and oxidative stress predominate in distinct time windows of the disease progression.

Serum biomarker analysis at the protein level on pulmonary hypertension secondary to old anterior myocardial infarction

Pulmonary hypertension (PH) related to old anterior myocardial infarction (OAMI) always accompanies a bad prognosis, and thus, we aimed to screen serum biomarkers related to PH in OAMI patients. According to right ventricular systolic pressure, we divided mice into sham, OAMI, and PH-OAMI groups and evaluated body, heart and lung weight, heart function, pulmonary blood flow velocity, cardiac fibrotic area, and pulmonary arteriole condition. Lung and serum were under the proteomic analysis. Levels of three identified proteins were measured. Compared with sham and OAMI mice, PH-OAMI mice showed heart dysfunction, low pulmonary blood flow, high right ventricular systolic pressure, heavy heart and lung weight, large cardiac fibrotic area, and pathological pulmonary arteriole remodeling (P<0.05 or P<0.01). Haptoglobin, annexin A5, and Ig mu chain C region of lung and serum were changed significantly in PH-OAMI mice (P<0.01). Then, we collected serum and clinical data, measured three serum protein levels, and performed multivariate regression and receiver operating characteristic curve in patients (normal, OAMI, and PH-OAMI groups). Compared with normal and OAMI patients, serum levels of three proteins in PH-OAMI patients were also altered notably (P<0.01). These three proteins can predict PH in OAMI patients (P<0.01). Receiver operating characteristic curve analysis revealed haptoglobin (cut-off value: 78.295, sensitivity: 62.8%, specificity: 94.4%), annexin A5 (cut-off value: 151.925, sensitivity: 41.9%, specificity: 82.4%), and Ig mu chain C region (cut-off value: 168.885, sensitivity: 86.0%, specificity: 79.6%) (P<0.01). Three circulating serum proteins can be useful for the categorization of OAMI patients with and without PH.

Approaching coronavirus disease 2019: Mechanisms of action of repurposed drugs with potential activity against SARS-CoV-2

On March 11, 2020, the World Health Organization (WHO) declared the severe acute respiratory syndrome caused by coronavirus 2 (SARS-CoV-2) a global pandemic. As of July 2020, SARS-CoV-2 has infected more than 14 million people and provoked more than 590,000 deaths, worldwide. From the beginning, a variety of pharmacological treatments has been empirically used to cope with the life-threatening complications associated with Corona Virus Disease 2019 (COVID-19). Thus far, only a couple of them and not consistently across reports have been shown to further decrease mortality, respect to what can be achieved with supportive care. In most cases, and due to the urgency imposed by the number and severity of the patients' clinical conditions, the choice of treatment has been limited to repurposed drugs, approved for other indications, or investigational agents used for other viral infections often rendered available on a compassionate-use basis. The rationale for drug selection was mainly, though not exclusively, based either i) on the activity against other coronaviruses or RNA viruses in order to potentially hamper viral entry and replication in the epithelial cells of the airways, and/or ii) on the ability to modulate the excessive inflammatory reaction deriving from dysregulated host immune responses against the SARS-CoV-2. In several months, an exceptionally large number of clinical trials have been designed to evaluate the safety and efficacy of anti-COVID-19 therapies in different clinical settings (treatment or pre- and post-exposure prophylaxis) and levels of disease severity, but only few of them have been completed so far. This review focuses on the molecular mechanisms of action that have provided the scientific rationale for the empirical use and evaluation in clinical trials of structurally different and often functionally unrelated drugs during the SARS-CoV-2 pandemic.

Pharmacologic therapy for pulmonary artery hypertension

PURPOSE OF REVIEW

Pulmonary arterial hypertension (PAH) is a disease that carries a significant mortality left untreated. This article aims to review pharmacotherapeutics for PAH.

RECENT FINDINGS

PAH-specific therapies have evolved over the last three decades and have expanded from one therapy in the 1990s to 14 FDA-approved medications. Current therapies are directed at restoring the imbalance of vasoactive mediators that include nitric oxide, endothelin and prostacyclin. Although these agents are effective as monotherapy, recent trials have promulgated the strategy of upfront combination therapy. The availability of oral prostacyclin agonists has also allowed for expanded treatment options. Risk assessment is vital in guiding therapy for PAH patients. There is ongoing focus on targeting pathological mechanisms of the disease via novel therapies and repurposing existing drugs.

SUMMARY

There is an array of medications available for the treatment of PAH. Prudent combination of therapies to maximize treatment effect can improve morbidity and mortality. This article reviews the data supporting these therapies and attempts to outline an approach to patient management.

Nutraceuticals in the Treatment of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a severe disease characterized by the loss and obstructive remodeling of the pulmonary arterial wall, causing a rise in pulmonary arterial pressure and pulmonary vascular resistance, which is responsible for right heart failure, functional decline, and death. Although many drugs are available for the treatment of this condition, it continues to be life-threatening, and its long-term treatment is expensive. On the other hand, many natural compounds present in food have beneficial effects on several cardiovascular conditions. Several studies have explored many of the potential beneficial effects of natural plant products on PAH. However, the mechanisms by which natural products, such as nutraceuticals, exert protective and therapeutic effects on PAH are not fully understood. In this review, we analyze the current knowledge on nutraceuticals and their potential use in the protection and treatment of PAH, as well as whether nutraceuticals could enhance the effects of drugs used in PAH through similar mechanisms.

Supporting the use of sildenafil infusions in paediatric and neonatal intensive care - A compatibility study

OBJECTIVE

Intravenous (IV) sildenafil, a phosphodiesterase type 5 inhibitor, is increasingly being used for the treatment of pulmonary hypertension (PH) in the paediatric population. Sildenafil (Revatio®) is approved for the treatment of pH in adults where it is administered as a bolus injection. However, in paediatrics it is used off-label and administered by continuous IV infusion. In the critically unwell child, limited IV access necessitates the administration of multiple IV infusions through a single IV lumen. The absence of compatibility data between sildenafil and other IV medications commonly used in this context necessitates the use of a dedicated IV line for sildenafil. The overall aim of this study was to establish the physical and chemical compatibility of sildenafil with commonly administered infusions in the paediatric and neonatal intensive care setting.

DESIGN

This study evaluated the chemical and physical compatibility of binary and multiple combinations (n = 42) of sildenafil with adrenaline, noradrenaline, milrinone, vasopressin and heparin. These were tested using three diluents (NaCl 0.9%w/v, Glucose 5%w/v, and Glucose 10%w/v) and two environmental conditions (room temperature and 37 °C) frequently encountered in paediatric or neonatal intensive care units. Prior to drug combination analysis, HPLC methods were developed and optimised to allow for the quantification of drugs in accordance with current pharmaceutical guidance. Binary and multiple drug mixtures of sildenafil were examined for physical and chemical compatibility to establish compatibility.

MEASUREMENTS AND MAIN RESULTS

Of the drug combinations not containing heparin, all were deemed compatible with the exception of the five drug mix of Sildenafil 800 μg/mL, Milrinone 200 μg/mL, Vasopressin 0.4Units/mL, Noradrenaline 60 μg/mL, Adrenaline 60 μg/mL at 37 °C, in 10%w/v glucose. All binary or multi drug combinations containing heparin were deemed incompatible.

CONCLUSIONS

This research provides support and information to clinicians looking to co-administer sildenafil with other IV medicines thus removing the requirement to subject their patients to multiple intravenous cannula insertion points where IV access is restricted.

ARTICLE TWEET

New evidence to support administration of sildenafil infusions in #PedsICU and #nicu- collaboration between @RCSIPharBioMol@FionaSOBrien1 and @OLCHCrumlin @RCSI_Irl @MoninneHowlett #CHI.