Metabolomics in Pulmonary Hypertension-A Useful Tool to Provide Insights into the Dark Side of a Tricky Pathology

Pulmonary hypertension (PH) is a multifaceted illness causing clinical manifestations like dyspnea, fatigue, and cyanosis. If left untreated, it often evolves into irreversible pulmonary arterial hypertension (PAH), leading to death. Metabolomics is a laboratory technique capable of providing insights into the metabolic pathways that are responsible for a number of physiologic or pathologic events through the analysis of a biological fluid (such as blood, urine, and sputum) using proton nuclear magnetic resonance spectroscopy or mass spectrometry. A systematic review was finalized according to the PRISMA scheme, with the goal of providing an overview of the research papers released up to now on the application of metabolomics to PH/PAH. So, eighty-five papers were identified, of which twenty-four concerning PH, and sixty-one regarding PAH. We found that, from a metabolic standpoint, the hallmarks of the disease onset and progression are an increase in glycolysis and impaired mitochondrial respiration. Oxidation is exacerbated as well. Specific metabolic fingerprints allow the characterization of some of the specific PH and PAH subtypes. Overall, metabolomics provides insights into the biological processes happening in the body of a subject suffering from PH/PAH. The disarranged metabolic pathways underpinning the disease may be the target of new therapeutic agents. Metabolomics will allow investigators to make a step forward towards personalized medicine.

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.

Bioinformatics analysis of the immune cell infiltration characteristics and correlation with crucial diagnostic markers in pulmonary arterial hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) is a pathophysiological syndrome, characterized by pulmonary vascular remodeling. Immunity and inflammation are progressively recognized properties of PAH, which are crucial for the initiation and maintenance of pulmonary vascular remodeling. This study explored immune cell infiltration characteristics and potential biomarkers of PAH using comprehensive bioinformatics analysis.

METHODS

Microarray data of GSE117261, GSE113439 and GSE53408 datasets were downloaded from Gene Expression Omnibus database. The differentially expressed genes (DEGs) were identified in GSE117261 dataset. The proportions of infiltrated immune cells were evaluated by CIBERSORT algorithm. Feature genes of PAH were selected by least absolute shrinkage and selection operator (LASSO) regression analysis and validated by fivefold cross-validation, random forest and logistic regression. The GSE113439 and GSE53408 datasets were used as validation sets and logistic regression and receiver operating characteristic (ROC) curve analysis were performed to evaluate the prediction value of PAH. The PAH-associated module was identified by weighted gene association network analysis (WGCNA). The intersection of genes in the modules screened and DEGs was used to construct protein-protein interaction (PPI) network and the core genes were selected. After the intersection of feature genes and core genes, the hub genes were identified. The correlation between hub genes and immune cell infiltration was analyzed by Pearson correlation analysis. The expression level of LTBP1 in the lungs of monocrotaline-induced PAH rats was determined by Western blotting. The localization of LTBP1 and CD4 in lungs of PAH was assayed by immunofluorescence.

RESULTS

A total of 419 DEGs were identified, including 223 upregulated genes and 196 downregulated genes. Functional enrichment analysis revealed that a significant enrichment in inflammation, immune response, and transforming growth factor β (TGFβ) signaling pathway. CIBERSORT analysis showed that ten significantly different types of immune cells were identified between PAH and control. Resting memory CD4+ T cells, CD8+ T cells, γδ T cells, M1 macrophages, and resting mast cells in the lungs of PAH patients were significantly higher than control. Seventeen feature genes were identified by LASSO regression for PAH prediction. WGCNA identified 15 co-expression modules. PPI network was constructed and 100 core genes were obtained. Complement C3b/C4b receptor 1 (CR1), thioredoxin reductase 1 (TXNRD1), latent TGFβ binding protein 1 (LTBP1), and toll-like receptor 1 (TLR1) were identified as hub genes and LTBP1 has the highest diagnostic efficacy for PAH (AUC = 0.968). Pearson correlation analysis showed that LTBP1 was positively correlated with resting memory CD4+ T cells, but negatively correlated with monocytes and neutrophils. Western blotting showed that the protein level of LTBP1 was increased in the lungs of monocrotaline-induced PAH rats. Immunofluorescence of lung tissues from rats with PAH showed increased expression of LTBP1 in pulmonary arteries as compared to control and LTBP1 was partly colocalized with CD4+ cells in the lungs.

CONCLUSION

LTBP1 was correlated with immune cell infiltration and identified as the critical diagnostic maker for PAH.

Association of red cell distribution width with pulmonary arterial hypertension in patients with mixed connective tissue disease

BACKGROUND

Pulmonary arterial hypertension (PAH) is a severe complication of mixed connective tissue disease (MCTD) and contributes to increased morbidity and mortality. Still, the demographic characteristics and risk factors of PAH in MCTD remain poorly understood. This study explored risk factors for PAH development in MCTD.

METHODS

Data from patients with MCTD and PAH hospitalized from May 2009 to December 2022 in a single center were collected and compared with patients with MCTD without PAH. The variables were analyzed by logistic regression to identify the factors associated with PAH in patients with MCTD. The receiver-operating characteristic (ROC) curve was used to assess the diagnostic value of the identified factors.

RESULTS

Finally, 119 patients with MCTD were included; 46 had PAH. The mean age at PAH onset and diagnosis was 38.9 ± 13.4 and 39.9 ± 13.7 years, respectively. The median pulmonary arterial systolic pressure (PASP) was 67.0 mmHg. The median brain natriuretic peptide (BNP) level was 180.0 pg/ml at PAH diagnosis. Red cell distribution width (RDW) (OR: 2.128; 95% confidence interval: 1.497-3.026; P < 0.001) was associated with PAH in patients with MCTD. There was a positive correlation between RDW and PASP (r = 0.716, P < 0.001). At a cutoff of 15.2%, RDW had the best sensitivity (80.4%) and specificity (82.2%) for PAH.

CONCLUSION

RDW may serve as a sensitive index to predict PAH in patients with MCTD.

Acid ceramidase gene therapy ameliorates pulmonary arterial hypertension with right heart dysfunction

BACKGROUND

Up-regulation of ceramides in pulmonary hypertension (PH), contributing to perturbations in sphingolipid homeostasis and the transition of cells to a senescence state. We assessed the safety, feasibility, and efficiency of acid ceramidase gene transfer in a rodent PH model.

METHODS

A model of PH was established by the combination of left pneumonectomy and injection of Sugen toxin. Magnetic resonance imaging and right heart catheterization confirmed development of PH. Animals were subjected to intratracheal administration of synthetic adeno-associated viral vector (Anc80L65) carrying the acid ceramidase (Anc80L65.AC), an empty capsid vector, or saline. Therapeutic efficacy was evaluated 8 weeks after gene delivery.

RESULTS

Hemodynamic assessment 4 weeks after PH model the development demonstrated an increase in the mean pulmonary artery pressure to 30.4 ± 2.13 mmHg versus 10.4 ± 1.65 mmHg in sham (p < 0.001), which was consistent with the definition of PH. We documented a significant increase in pulmonary vascular resistance in the saline-treated (6.79 ± 0.85 mm Hg) and empty capsid (6.94 ± 0.47 mm Hg) groups, but not in animals receiving Anc80L65.AC (4.44 ± 0.71 mm Hg, p < 0.001). Morphometric analysis demonstrated an increase in medial wall thickness in control groups in comparison to those treated with acid ceramidase. After acid ceramidase gene delivery, a significant decrease of pro-inflammatory factors, interleukins, and senescence markers was observed.

CONCLUSION

Gene delivery of acid ceramidase provided tropism to pulmonary tissue and ameliorated vascular remodeling with right ventricular dysfunction in pulmonary hypertension.

Pharmacology and Rationale for Seralutinib in the Treatment of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a complex disorder characterized by vascular remodeling and a consequent increase in pulmonary vascular resistance. The histologic hallmarks of PAH include plexiform and neointimal lesions of the pulmonary arterioles, which are composed of dysregulated, apoptosis-resistant endothelial cells and myofibroblasts. Platelet-derived growth factor receptors (PDGFR) α and β, colony stimulating factor 1 receptor (CSF1R), and mast/stem cell growth factor receptor kit (c-KIT) are closely related kinases that have been implicated in PAH progression. In addition, emerging data indicate significant crosstalk between PDGF signaling and the bone morphogenetic protein receptor type 2 (BMPR2)/transforming growth factor β (TGFβ) receptor axis. This review will discuss the importance of the PDGFR-CSF1R-c-KIT signaling network in PAH pathogenesis, present evidence that the inhibition of all three nodes in this kinase network is a potential therapeutic approach for PAH, and highlight the therapeutic potential of seralutinib, currently in development for PAH, which targets these pathways.

Outcomes of pregnancy in women with different types of pulmonary hypertension

BACKGROUND

Pulmonary hypertension (PH) is considered to increase maternal and fetal risk, and we attempt to explore pregnancy outcomes in women with different types of PH.

METHODS

We retrospectively analyzed the clinical data of pregnant women with PH who were admitted to Anzhen Hospital from January 2010 to December 2019, and followed up on these parturients and their offspring.

RESULTS

Three hundred and sixty-six pregnant women with PH were collected, including 265 pulmonary arterial hypertension (PAH) associated with congenital heart disease (CHD), 65 PH caused by left heart disease, 12 idiopathic PH, and 24 PH associated with other diseases. Maternal mean age was 28.4 ± 4.4 years and 72.1% were nulliparous. The estimated systolic pulmonary artery pressure was < 50 mmHg in 40.2% of patients, 50-70 mmHg in 23.2%, and > 70 mmHg in 36.6%. In more than 94% of women, a diagnosis of PH was made before pregnancy. During pregnancy, heart failure occurred in 15% of patients. Cesarean section was performed in 90.5% (20.4% emergency). Complications included fetal mortality (0.5%), preterm delivery (40.4%), and low birth weight (37.7%). A total of 20 mothers died (5.5%). The highest mortality rate was found in patients with idiopathic PH (4/12, 33.3%). A total of 12 children died (3.3%), 5 (1.4%) of them after discharge from the hospital, and 7 (1.9%) were in hospital.

CONCLUSIONS

Although most of these women are fertile, PH does increase maternal and fetal risk. Women with idiopathic PH and Eisenmenger syndrome are not recommended to have children.

Long-Term Safety, Outcome, and Clinical Effects of Subcutaneous and Intravenous Treprostinil Treatment in Patients with Severe Chronic Pulmonary Arterial Hypertension

BACKGROUND

Current guidelines recommend treatment with parenteral prostacyclin analogs in patients with severe pulmonary arterial hypertension (PAH), who have insufficient response to treatment. Real-life data are sought to help physicians in treatment decisions and clinical care of patients.

OBJECTIVE

This study analyzed safety, clinical effects, and long-term outcomes of subcutaneous (sc) and/or intravenous (iv) treprostinil via different pump systems in consecutive patients with PAH.

METHODS

Thirty-seven patients with severe progressive PAH despite dual combination therapy (20 female, mean age: 52.3 ± 15 years, mean pulmonary vascular resistance: 12.1 ± 5.1 WU) were initiated with add-on treprostinil sc and were routinely clinically assessed. Changes in clinical parameters, adverse events, and outcome were analyzed retrospectively.

RESULTS

In 24 of 37 patients, treprostinil administration was continued iv via implantation of LENUS Pro® pump after 3 ± 1.3 months, 6 patients continued with sc therapy, and 7 discontinued treatment. After 3, 6, 9, and 12 months of treprostinil treatment, patients showed a significant improvement in mean 6-min walk distance and tricuspid annular plane systolic excursion compared to baseline. In 8 of the 24 patients, iv pumps required surgical revision. During a mean follow-up of 2.82 ± 1.95 years, 12 patients died, four received lung transplantation. Transplant-free survival after 1, 2, and 3 years was 85.7%, 69.2%, and 65.3%, respectively.

CONCLUSION

sc treprostinil as add-on to double combination treatment significantly improved exercise capacity and right heart function. In most patients, treprostinil could be continued via more tolerable iv administration approach (LENUS Pro® pump), showing reasonable overall survival with respect to the severity of PAH.

Pulmonary Artery Strain Predicts Prognosis in Pulmonary Arterial Hypertension

BACKGROUND

Current cardiac magnetic resonance (CMR) imaging in pulmonary arterial hypertension (PAH) focuses on measures of ventricular function and coupling.

OBJECTIVES

The purpose of this study was to evaluate pulmonary artery (PA) global longitudinal strain (GLS) as a prognostic marker in patients with PAH.

METHODS

The authors included 169 patients with PAH from the ASPIRE (Assessing the Spectrum of Pulmonary hypertension Identified at a REferral centre) and INITIATE (Integrated computatioNal modelIng of righT heart mechanIcs and blood flow dynAmics in congeniTal hEart disease) registries, and 82 normal controls with similar age and gender distributions. PA GLS was derived from CMR feature tracking. Right ventricular measurements including volumes, ejection fraction, and right ventricular GLS were also derived from CMR. Patients were followed up a median of 34 months with all-cause mortality as the primary endpoint. Other known risk scores were collected, including the REVEAL (Registry to Evaluate Early and Long-term Pulmonary Arterial Hypertension Disease Management) 2.0 and COMPERA (Comparative, Prospective Registry of Newly Initiated Therapies for Pulmonary Hypertension) 2.0 scores.

RESULTS

Of 169 patients (mean age: 57 ± 15 years; 80% female), 45 (26.6%) died (median follow-up: 34 months). Mean PA GLS was 23% ± 6% in normal controls and 10% ± 5% in patients with PAH (P < 0.0001). Patients with PA GLS <9% had a higher risk of mortality than those with PA GLS ≥9% (P < 0.001), and this was an independent predictor of mortality in PAH on multivariable analysis after adjustment for known risk factors (HR: 2.93; P = 0.010). Finally, in patients with PAH, PA GLS provided incremental prognostic value over the REVEAL 2.0 (global chi-square; P = 0.001; C statistic comparison; P = 0.030) and COMPERA 2.0 (global chi-square; P = 0.001; C statistic comparison; P = 0.048).

CONCLUSIONS

PA GLS confers incremental prognostic utility over the established risk scores for identifying patients with PAH at higher risk of death, who may be targeted for closer monitoring and/or intensified therapy.

Performance of risk stratification scores and role of comorbidities in older vs younger patients with pulmonary arterial hypertension

BACKGROUND

Risk scores are important tools for the prognostic stratification of pulmonary arterial hypertension (PAH). Their performance and the additional impact of comorbidities across age groups is unknown.

METHODS

Patients with PAH enrolled from 2001 to 2021 were divided in ≥65 years old vs <65 years old patients. Study outcome was 5-year all-cause mortality. French Pulmonary Hypertension Network (FPHN), FPHN noninvasive, Comparative, Prospective Registry of Newly Initiated Therapies for Pulmonary Hypertension (COMPERA) and Registry to Evaluate Early and Long-term PAH Disease Management (REVEAL 2.0) risk scores were calculated and patients categorized at low, intermediate and high risk. Number of comorbidities was calculated.

RESULTS

Among 383 patients, 152 (40%) were ≥65 years old. They had more comorbidities (number of comorbidities 2, IQR 1-3, vs 1, IQR 0-2 in <65 years patients). Five-year survival was 63% in ≥65 vs 90% in <65 years. Risk scores correctly discriminated the different classes of risk in the overall cohort and in the older and younger groups. REVEAL 2.0 showed the best accuracy in the total cohort (C-index 0.74, standard error-SE- 0.03) and older (C-index 0.69, SE 0.03) patients, whereas COMPERA 2.0 performed better in younger patients (C-index 0.75, SE 0.08). Number of comorbidities was associated with higher 5-year mortality, and consistently increased the accuracy of risk scores, in younger but not in older patients.

CONCLUSIONS

Risk scores have similar accuracy in the prognostic stratification of older vs younger PAH patients. REVEAL 2.0 had the best performance in older patients and COMPERA 2.0 had it in younger patients. Comorbidities increased the accuracy of risk scores only in younger patients.

Establishing minimally important differences for cardiac MRI end-points in pulmonary arterial hypertension

BACKGROUND

Cardiac magnetic resonance (CMR) is the gold standard technique to assess biventricular volumes and function, and is increasingly being considered as an end-point in clinical studies. Currently, with the exception of right ventricular (RV) stroke volume and RV end-diastolic volume, there is only limited data on minimally important differences (MIDs) reported for CMR metrics. Our study aimed to identify MIDs for CMR metrics based on US Food and Drug Administration recommendations for a clinical outcome measure that should reflect how a patient "feels, functions or survives".

METHODS

Consecutive treatment-naïve patients with pulmonary arterial hypertension (PAH) between 2010 and 2022 who had two CMR scans (at baseline prior to treatment and 12 months following treatment) were identified from the ASPIRE registry. All patients were followed up for 1 additional year after the second scan. For both scans, cardiac measurements were obtained from a validated fully automated segmentation tool. The MID in CMR metrics was determined using two distribution-based (0.5sd and minimal detectable change) and two anchor-based (change difference and generalised linear model regression) methods benchmarked to how a patient "feels" (emPHasis-10 quality of life questionnaire), "functions" (incremental shuttle walk test) or "survives" for 1-year mortality to changes in CMR measurements.

RESULTS

254 patients with PAH were included (mean±sd age 53±16 years, 79% female and 66% categorised as intermediate risk based on the 2022 European Society of Cardiology/European Respiratory Society risk score). We identified a 5% absolute increase in RV ejection fraction and a 17 mL decrease in RV end-diastolic or end-systolic volumes as the MIDs for improvement. Conversely, a 5% decrease in RV ejection fraction and a 10 mL increase in RV volumes were associated with worsening.

CONCLUSIONS

This study establishes clinically relevant CMR MIDs for how a patient "feels, functions or survives" in response to PAH treatment. These findings provide further support for the use of CMR as a clinically relevant clinical outcome measure and will aid trial size calculations for studies using CMR.

Treatment effects of pulmonary artery denervation for pulmonary arterial hypertension stratified by REVEAL risk score: Results from PADN-CFDA trial

BACKGROUND

The differential treatment effect of pulmonary artery denervation (PADN) in pulmonary arterial hypertension (PAH) patients with different risk burdens remains unclear. This study aimed to determine the effectiveness of PADN in low vs intermediate-high-risk PAH patients.

METHODS

In total, 128 patients with treatment naive PAH included in the PADN-CFDA trial were categorized into low-risk and intermediate-high-risk patients. The primary endpoint was the between-group difference in the change in 6-min walk distance (6 MWD) from baseline to 6 months.

RESULTS

In the intermediate-high-risk group, those treated with PADN and PDE-5i had a greater improvement in 6 MWD from baseline to 6 months as compared to those treated with sham plus PDE-5i. From baseline to 6 months, pulmonary vascular resistance (PVR) was reduced by -6.1 ± 0.6 and -2.0 ± 0.7 Wood units following PADN plus PDE-5i and sham plus PDE-5i, respectively, along with the significant reduction of NT-proBNP in the intermediate-high-risk group. However, there were no significant differences in 6 MWD, PVR, and NT-proBNP between the PADN plus PDE-5i and sham plus PDE-5i groups among low-risk patients. Moreover, the right ventricular function was equally improved by PADN treatment across the low-, intermediate-, and high-risk groups. Clinical worsening was less with PADN plus PDE-5i treatment during the 6-month follow-up.

CONCLUSIONS

In patients with pulmonary arterial hypertension, pulmonary artery denervation plus PDE-5i improved exercise capacity, NT-proBNP, hemodynamic, and clinical outcomes during the 6-month follow-up among intermediate-high risk patients.

Maresin-1 protects against pulmonary arterial hypertension by improving mitochondrial homeostasis through ALXR/HSP90α axis

AIMS

Pulmonary arterial hypertension (PAH) is a progressive and lethal disease characterized by continuous proliferation of pulmonary arterial smooth muscle cell (PASMCs) and increased pulmonary vascular remodeling. Maresin-1 (MaR1) is a member of pro-resolving lipid mediators and exhibits protective effects on various inflammation-related diseases. Here we aimed to study the role of MaR1 in the development and progression of PAH and to explore the underlying mechanisms.

METHODS AND RESULTS

We evaluated the effect of MaR1 treatment on PAH in both monocrotaline (MCT)-induced rat and hypoxia+SU5416 (HySu)-induced mouse models of pulmonary hypertension (PH). Plasma samples were collected from patients with PAH and rodent PH models to examine MaR1 production. Specific shRNA adenovirus or inhibitors were used to block the function of MaR1 receptors. The data showed that MaR1 significantly prevented the development and blunted the progression of PH in rodents. Blockade of the function of MaR1 receptor ALXR, but not LGR6 or RORα, with BOC-2, abolished the protective effect of MaR1 against PAH development and reduced its therapeutic potential. Mechanistically, we demonstrated that the MaR1/ALXR axis suppressed hypoxia-induced PASMCs proliferation and alleviated pulmonary vascular remodeling by inhibiting mitochondrial accumulation of heat shock protein 90α (HSP90α) and restoring mitophagy.

CONCLUSION

MaR1 protects against PAH by improving mitochondrial homeostasis through ALXR/HSP90α axis and represents a promising target for PAH prevention and treatment.

Estimation of the effect of atezolizumab plus bevacizumab on pulmonary arterial hypertension using computed tomography in HCC patients

The effect of the combination of atezolizumab and bevacizumab (Atez/Bev) for hepatocellular carcinoma (HCC) on pulmonary arterial hypertension (PAH) is unknown. Estimation of PAH by using computed tomography (CT) has recently been proposed. Thus, we aimed to estimate the effect of Atez/Bev on PAH using CT. Altogether, 113 patients who received Atez/Bev for HCC were enrolled. Probable PAH was defined as the diameter of the main pulmonary artery (mPA-D) ≥ 33 mm, whereas suspicious PAH was defined as mPA-D ≥ 29 mm or mPA-D/the diameter of the ascending aorta (aAo-D) ≥ 1.0. Before treatment, probable/suspicious PAH were diagnosed in 7 (6.7%)/22 (21.0%) patients, respectively. mPA-D and mPA-D/aAo-D significantly increased after induction of Atez/Bev. The increment of mPA-D was correlated with the occurrence of post-treatment respiratory/heart failure. In analysis of 55 patients who underwent CT at 3 months after the last dose of Atez/Bev, mPA-D and mPA-D/aAo-D significantly decreased. However, in the group with continuous treatment of other molecular-targeted drugs after Atez/Bev, mPA-D and mPA-D/aAo-D showed no significant change. In conclusion, PAH may not be a rare complication in patients with HCC and should be managed carefully because of the possible negative effect of Atez/Bev on PAH.

COVID-19 in congenital heart disease (COaCHeD) study

BACKGROUND

COVID-19 has caused significant worldwide morbidity and mortality. Congenital heart disease (CHD) is likely to increase vulnerability and understanding the predictors of adverse outcomes is key to optimising care.

OBJECTIVE

Ascertain the impact of COVID-19 on people with CHD and define risk factors for adverse outcomes.

METHODS

Multicentre UK study undertaken 1 March 2020-30 June 2021 during the COVID-19 pandemic. Data were collected on CHD diagnoses, clinical presentation and outcomes. Multivariable logistic regression with multiple imputation was performed to explore predictors of death and hospitalisation.

RESULTS

There were 405 reported cases (127 paediatric/278 adult). In children (age <16 years), there were 5 (3.9%) deaths. Adjusted ORs (AORs) for hospitalisation in children were significantly lower with each ascending year of age (OR 0.85, 95% CI 0.75 to 0.96 (p<0.01)). In adults, there were 24 (8.6%) deaths (19 with comorbidities) and 74 (26.6%) hospital admissions. AORs for death in adults were significantly increased with each year of age (OR 1.05, 95% CI 1.01 to 1.10 (p<0.01)) and with pulmonary arterial hypertension (PAH; OR 5.99, 95% CI 1.34 to 26.91 (p=0.02)). AORs for hospitalisation in adults were significantly higher with each additional year of age (OR 1.03, 95% CI 1.00 to 1.05 (p=0.04)), additional comorbidities (OR 3.23, 95% CI 1.31 to 7.97 (p=0.01)) and genetic disease (OR 2.87, 95% CI 1.04 to 7.94 (p=0.04)).

CONCLUSIONS

Children were at low risk of death and hospitalisation secondary to COVID-19 even with severe CHD, but hospital admission rates were higher in younger children, independent of comorbidity. In adults, higher likelihood of death was associated with increasing age and PAH, and of hospitalisation with age, comorbidities and genetic disease. An individualised approach, based on age and comorbidities, should be taken to COVID-19 management in patients with CHD.

Characteristics, treatments and survival of pulmonary arterial hypertension associated with congenital heart disease in China: Insights from a national multicenter prospective registry

BACKGROUND

The purpose of this registry was to provide insights into the characteristics, treatments and survival of patients with PAH-CHD in China.

METHODS

Patients diagnosed with PAH-CHD were enrolled in this national multicenter prospective registry. Baseline and follow-up data on clinical characteristics, PAH-targeted treatments and survival were collected.

RESULTS

A total of 1060 PAH-CHD patients (mean age 31 years; 67.9% females) were included, with Eisenmenger syndrome (51.5%) being the most common form and atrial septal defects (37.3%) comprising the most frequent underlying defect. Approximately 33.0% of the patients were in World Health Organization functional class III to IV. The overall mean pulmonary arterial pressure and pulmonary vascular resistance were 67.1 (20.1) mm Hg and 1112.4 (705.9) dyn/s/cm5, respectively. PAH-targeted therapy was utilized in 826 patients (77.9%), and 203 patients (19.1%) received combination therapy. The estimated 1-, 3-, 5-, and 10-year survival rates of the overall cohort were 96.9%, 92.9%, 87.6% and 73.0%, respectively. Patients received combination therapy had significantly better survival than those with monotherapy (p = 0.016). NT-proBNP >1400 pg/ml, SvO2 ≤ 65% and Borg dyspnea index ≥ 3 and PAH-targeted therapy were independent predictors of mortality. Hemoglobin > 160g/L was a unique predictor for mortality in Eisenmenger syndrome.

CONCLUSIONS

Chinese PAH-CHD patients predominantly exhibit Eisenmenger syndrome and have significantly impaired exercise tolerance and right ventricular function at diagnosis, which are closely associated with long-term survival. PAH-targeted therapy including combination therapy showed a favorable effect on survival in PAH-CHD. The long-term survival of Chinese CHD-PAH patients remains to be improved.

Identification of ACKR4 as an immune checkpoint in pulmonary arterial hypertension

Objective

Inflammation is recognized as a contributor in the development of pulmonary arterial hypertension (PAH), and the recruitment and functional capacity of immune cells are well-orchestrated by chemokines and their receptors. This study is aimed at identification of critical chemokines in the progression of PAH via transcriptomic analysis.

Methods

Differentially expressed genes (DEGs) from lungs of PAH patients were achieved compared to controls based on Gene Expression Omnibus (GEO) database. Gene set enrichment analysis (GSEA) was applied for functional annotation and pathway enrichement. The abundance of immune cells was estimated by the xCell algorithm. Weighted correlation network analysis (WGCNA) was used to construct a gene expression network, based on which a diagnostic model was generated to determine its accuracy to distinguish PAH from control subjects. Target genes were then validated in lung of hypoxia-induce pulmonary hypertension (PH) mouse model.

Results

ACKR4 (atypical chemokine receptor 4) was downregulated in PAH lung tissues in multiple datasets. PAH relevant biological functions and pathways were enriched in patients with low-ACKR4 level according to GSEA enrichment analysis. Immuno-infiltration analysis revealed a negative correlation of activated dendritic cells, Th1 and macrophage infiltration with ACKR4 expression. Three gene modules were associated with PAH via WGCNA analysis, and a model for PAH diagnosis was generated using CXCL12, COL18A1 and TSHZ2, all of which correlated with ACKR4. The ACKR4 expression was also downregulated in lung tissues of our experimental PH mice compared to that of controls.

Conclusions

The reduction of ACKR4 in lung tissues of human PAH based on transcriptomic data is consistent with the alteration observed in our rodent PH. The correlation with immune cell infiltration and functional annotation indicated that ACKR4 might serve as a protective immune checkpoint for PAH.

Metabolic profiling of in vivo right ventricular function and exercise performance in pulmonary arterial hypertension

Right ventricular (RV) adaptation is the principal determinant of outcomes in pulmonary arterial hypertension (PAH), however, RV function is challenging to assess. RV responses to hemodynamic stressors are particularly difficult to interrogate without invasive testing. This study sought to identify metabolomic markers of in vivo right ventricular function and exercise performance in PAH. Consecutive subjects with PAH (n = 23) underwent rest and exercise right heart catheterization with multibeat pressure volume loop analysis. Pulmonary arterial blood was collected at rest and during exercise. Mass spectrometry-based targeted metabolomics were performed, and metabolic associations with hemodynamics and comprehensive measures of RV function were determined using sparse partial least squares regression. Metabolite profiles were compared with N-terminal prohormone of B-type natriuretic peptide (NT-proBNP) measurements for accuracy in modeling ventriculo-arterial parameters. Thirteen metabolites changed in abundance with exercise, including metabolites reflecting increased arginine bioavailability, precursors of catecholamine and nucleotide synthesis, and branched-chain amino acids. Higher resting arginine bioavailability predicted more favorable exercise hemodynamics and pressure-flow relationships. Subjects with more severe PAH augmented arginine bioavailability with exercise to a greater extent than subjects with less severe PAH. We identified relationships between kynurenine pathway metabolism and impaired ventriculo-arterial coupling, worse RV diastolic function, lower RV contractility, diminished RV contractility with exercise, and RV dilation with exercise. Metabolite profiles outperformed NT-proBNP in modeling RV contractility, diastolic function, and exercise performance. Specific metabolite profiles correspond to RV functional measurements only obtainable via invasive pressure-volume loop analysis and predict RV responses to exercise. Metabolic profiling may inform discovery of RV functional biomarkers.NEW & NOTEWORTHY In this cohort of patients with pulmonary arterial hypertension (PAH), we investigate metabolomic associations with comprehensive right ventricular (RV) functional measurements derived from multibeat RV pressure-volume loop analysis. Our results show that tryptophan metabolism, particularly the kynurenine pathway, is linked to intrinsic RV function and PAH pathobiology. Findings also highlight the importance of arginine bioavailability in the cardiopulmonary system's response to exercise stress. Metabolite profiles selected via unbiased analysis outperformed N-terminal prohormone of B-type natriuretic peptide (NT-proBNP) in predicting load-independent measures of RV function at rest and cardiopulmonary system performance under stress. Overall, this work suggests the potential for select metabolites to function as disease-specific biomarkers, offers insights into PAH pathobiology, and informs discovery of potentially targetable RV-centric pathways.

Thoracic Spinal Cord Neuroinflammation as a Novel Therapeutic Target in Pulmonary Hypertension

BACKGROUND

Pulmonary hypertension (PH) is associated with aberrant sympathoexcitation leading to right ventricular failure (RVF), arrhythmias, and death. Microglial activation and neuroinflammation have been implicated in sympathoexcitation in experimental PH. We recently reported the first evidence of thoracic spinal cord (TSC) neuroinflammation in PH rats. Here, we hypothesize that PH is associated with increased cardiopulmonary afferent signaling leading to TSC-specific neuroinflammation and sympathoexcitation. Furthermore, inhibition of TSC neuroinflammation rescues experimental PH and RVF.

METHODS

We performed transcriptomic analysis and its validation on the TSC of monocrotaline (n=8) and Sugen hypoxia (n=8) rat models of severe PH-RVF. A group of monocrotaline rats received either daily intrathecal microglial activation inhibitor minocycline (200 μg/kg per day, n=5) or PBS (n=5) from day 14 through 28. Echocardiography and right ventricle-catheterization were performed terminally. Real-time quantitative reverse transcription PCR, immunolocalization, microglia+astrocyte quantification, and terminal deoxynucleotidyl transferase dUTP nick end labeling were assessed. Plasma catecholamines were measured by ELISA. Human spinal cord autopsy samples (Control n=3; pulmonary arterial hypertension n=3) were assessed to validate preclinical findings.

RESULTS

Increased cardiopulmonary afferent signaling was demonstrated in preclinical and clinical PH. Our findings delineated common dysregulated genes and pathways highlighting neuroinflammation and apoptosis in the remodeled TSC and highlighted increased sympathoexcitation in both rat models. Moreover, we validated significantly increased microglial and astrocytic activation and CX3CL1 expression in TSC of human pulmonary arterial hypertension. Finally, amelioration of TSC neuroinflammation by minocycline in monocrotaline rats inhibited microglial activation, decreased proinflammatory cytokines, sympathetic nervous system activation and significantly attenuated PH and RVF.

CONCLUSIONS

Targeting neuroinflammation and associated molecular pathways and genes in the TSC may yield novel therapeutic strategies for PH and RVF.

Hemodynamic Effects of a High-Frequency Oscillatory Ventilation Open-Lung Strategy in Critically Ill Children With Acquired or Congenital Cardiac Disease

OBJECTIVES

To study the hemodynamic consequences of an open-lung high-frequency oscillatory ventilation (HFOV) strategy in patients with an underlying cardiac anomaly with or without intracardiac shunt or primary pulmonary hypertension with severe lung injury.

DESIGN

Secondary analysis of prospectively collected data.

SETTING

Medical-surgical PICU.

PATIENTS

Children less than 18 years old with cardiac anomalies (± intracardiac shunt) or primary pulmonary hypertension.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Data from 52 subjects were analyzed, of whom 39 of 52 with cardiac anomaly (23/39 with intracardiac shunt) and 13 of 52 with primary pulmonary hypertension. Fourteen patients were admitted postoperatively, and 26 patients were admitted with acute respiratory failure. Five subjects (9.6%) were canulated for ECMO (of whom four for worsening respiratory status). Ten patients (19.2%) died during PICU stay. Median conventional mechanical ventilation settings prior to HFOV were peak inspiratory pressure 30 cm H 2 O (27-33 cm H 2 O), positive end-expiratory pressure 8 cm H 2 O (6-10 cm H 2 O), and F io2 0.72 (0.56-0.94). After transitioning to HFOV, there was no negative effect on mean arterial blood pressure, central venous pressure, or arterial lactate. Heart rate decreased significantly over time ( p < 0.0001), without group differences. The percentage of subjects receiving a fluid bolus decreased over time ( p = 0.003), especially in those with primary pulmonary hypertension ( p = 0.0155) and without intracardiac shunt ( p = 0.0328). There were no significant differences in the cumulative number of daily boluses over time. Vasoactive Infusion Score did not increase over time. Pa co2 decreased ( p < 0.0002) and arterial pH significantly improved ( p < 0.0001) over time in the whole cohort. Neuromuscular blocking agents were used in all subjects switched to HFOV. Daily cumulative sedative doses were unchanged, and no clinically apparent barotrauma was found.

CONCLUSIONS

No negative hemodynamic consequences occurred with an individualized, physiology-based open-lung HFOV approach in patients with cardiac anomalies or primary pulmonary hypertension suffering from severe lung injury.