Association of non-insulin-based insulin resistance indices with disease severity and adverse outcome in idiopathic pulmonary arterial hypertension: a multi-center cohort study.

BACKGROUND: Insulin resistance (IR) plays an important role in the pathophysiology of cardiovascular disease. Recent studies have shown that diabetes mellitus and impaired lipid metabolism are associated with the severity and prognosis of idiopathic pulmonary arterial hypertension (IPAH). However, the relationship between IR and pulmonary hypertension is poorly understood. This study explored the association between four IR indices and IPAH using data from a multicenter cohort. METHODS: A total of 602 consecutive participants with IPAH were included in this study between January 2015 and December 2022. The metabolic score for IR (METS-IR), triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio, triglyceride and glucose (TyG) index, and triglyceride-glucose-body mass index (TyG-BMI) were used to quantify IR levels in patients with IPAH. The correlation between non-insulin-based IR indices and long-term adverse outcomes was determined using multivariate Cox regression models and restricted cubic splines. RESULTS: During a mean of 3.6 years' follow-up, 214 participants experienced all-cause death or worsening condition. Compared with in low to intermediate-low risk patients, the TG/HDL-C ratio (2.9 ± 1.7 vs. 3.3 ± 2.1, P = 0.003) and METS-IR (34.5 ± 6.7 vs. 36.4 ± 7.5, P < 0.001) were significantly increased in high to intermediate-high risk patients. IR indices correlated with well-validated variables that reflected the severity of IPAH, such as the cardiac index and stroke volume index. Multivariate Cox regression analyses indicated that the TyG-BMI index (hazard ratio [HR] 1.179, 95% confidence interval [CI] 1.020, 1.363 per 1.0-standard deviation [SD] increment, P = 0.026) and METS-IR (HR 1.169, 95% CI 1.016, 1.345 per 1.0-SD increment, P = 0.030) independently predicted adverse outcomes. Addition of the TG/HDL-C ratio and METS-IR significantly improved the reclassification and discrimination ability beyond the European Society of Cardiology (ESC) risk score. CONCLUSIONS: IR is associated with the severity and long-term prognosis of IPAH. TyG-BMI and METS-IR can independently predict clinical worsening events, while METS-IR also provide incremental predictive performance beyond the ESC risk stratification.

New prognostic markers in pulmonary arterial hypertension: CRP to albumin ratio and uric acid.

INTRODUCTION: Idiopathic pulmonary hypertension(IPAH) is a rare disease that causes severe morbidity and mortality despite advances in treatment management. Evaluating the prognosis of the disease is critical in determining therapeutic approaches. We aimed to evaluate the prognostic significance of C-reactive protein/albumin ratio (CAR) and uric acid, which is an easily applicable and inexpensive parameter in patients with IPAH. METHODS: Seventy-two IPAH patients and 99 consecutive non-IPAH patients as a control group were enrolled in the study retrospectively. Right heart catheterization(RHC), echocardiography, and laboratory parameters of the two groups and those who died and survived among the IPAH patients were compared. RESULTS: IPAH and control group were compared at the first stage and CAR (1.98(0.28-10.74), 0.75(0.22-4.7),respectively;p < 0.01) and uric acid (0.33(0.19-0.87), 0.3(0.11-0.48) mmol/L, respectively; p = 0.03) values were significantly higher in the pulmonary hypertension group compared to the control group. Compared with the surviving IPAH patients, CAR (4.60(1.39-10.74),1.54(0.28-6.74),respectively;p < 0.001) and uric acid levels (0.458(0.26-0.87), 0.315(0.19-0.56) mmol/L, respectively; p < 0.001) were significantly higher in the group of patients who died. In the multivariate Cox regression models uric acid(p < 0.001) and CAR(p < 0.001) were found to be associated with survival time. Receiver operating characteristic curves (ROC) analyses showed that > 1.54 CAR value (AUC = 0.81,Sens:85.7%,Spec:56.9%,p < 0.001) and > 5.85 mg/dL (>0.348 mmol/L) uric acid value (AUC = 0.864, Sens:85.7%, Spec:78.4%, p < 0.001) are strong predictors for mortality. CONCLUSION: In this study, we showed that simple markers such as CAR, which augment the inflammation marker feature of CRP, and uric acid can give prognostic information in PAH patients.

Risk assessment in pulmonary hypertension based on routinely measured laboratory parameters.

BACKGROUND: γ-glutamyl transferase (GGT), the aspartate aminotransferase/alanine aminotransferase (AST/ALT) ratio, and the neutrophil-to-lymphocyte ratio (NLR) are prognostic biomarkers in several cardiovascular diseases, but their relevance in pulmonary hypertension (PH) is not fully understood. We aimed to assess their prognostic value in patients with pulmonary arterial hypertension (PAH) and chronic thromboembolic PH (CTEPH). METHODS: We retrospectively analyzed 731 incident patients with idiopathic PAH or CTEPH who entered the Giessen PH registry during 1993-2019. A risk stratification score based on GGT, AST/ALT ratio, and NLR tertiles was compared with a truncated version of the European Society of Cardiology/European Respiratory Society (ESC/ERS) risk stratification scheme. Associations with survival were evaluated using Kaplan-Meier and Cox regression analyses. External validation was performed in 311 patients with various types of PAH or CTEPH from a second German center. RESULTS: GGT levels, AST/ALT, and NLR independently predicted mortality at baseline and during follow-up. The scoring system based on these biomarkers predicted mortality at baseline and during follow-up (both log-rank p < 0.001; hazard ratio [95% confidence interval], high vs low risk: baseline, 7.6 [3.9, 15.0]; follow-up, 13.3 [4.8, 37.1]). Five-year survival of low, intermediate, and high risk groups was 92%, 76%, and 51%, respectively, at baseline and 95%, 78%, and 50%, respectively, during follow-up. Our scoring system showed characteristics comparable to the ESC/ERS scheme, and predicted mortality in the validation cohort. CONCLUSION: GGT, AST/ALT, and NLR were reliable prognostic biomarkers at baseline and during follow-up, with predictive power comparable to the gold standard for risk stratification.

Plasma irisin levels are associated with hemodynamic and clinical outcome in idiopathic pulmonary arterial hypertension patients.

Irisin has been considered to reflect oxidative stress. This study aimed to show whether plasma irisin levels are correlated with hemodynamic dysfunction and predict the clinical outcome of patients with idiopathic pulmonary arterial hypertension (IPAH). A total of 68 adult IPAH patients were prospectively recruited in the present study. Plasma irisin levels were measured by the ELISA method in enrolled IPAH patients. Baseline clinical characteristics, and hemodynamic and clinical outcome were compared according to different plasma irisin levels. IPAH patients were divided into high irisin group (irisin ≥ 7.3 µg/ml) and low irisin group (irisin < 7.3 µg/ml) according to median values of irisin levels. Total plasma cholesterol levels (P = 0.027) and low-density lipoprotein cholesterol (LDL-C) levels (P = 0.042) were higher in high irisin group and were positively correlated with plasma irisin levels. IPAH patients in low irisin group had a significantly higher mean pulmonary artery pressure (mPAP, P = 0.047), systolic pulmonary artery pressure (sPAP, P = 0.022), systolic right-ventricular pressure (sRVP, P = 0.007), mean right atrial pressure (mRAP, P = 0.043), and systolic right atrial pressure (sRAP, P = 0.020). mRAP, sRAP, and diastolic right atrial pressure (dRAP) were negatively correlated with plasma irisin levels. Low irisin group predicts adverse hemodynamic status and poor free of event survival rate (P = 0.030, log-rank test). Multivariate analysis indicates plasma irisin levels to be an independent predictor of prognosis in IPAH patients after adjusting for related covariates (HR 0.786; 95% CI 0.584, 0.957; P = 0.038). Plasma irisin levels may serve as a novel biomarker in IPAH patients for hemodynamic severity assessment and clinical outcome evaluation.

Distinct patterns of soluble leukocyte activation markers are associated with etiology and outcomes in precapillary pulmonary hypertension.

Activation of inflammatory processes has been identified as a major driver of pulmonary vascular remodeling that contributes to the development of precapillary pulmonary hypertension (PH). We hypothesized that circulating markers of leukocyte activation, reflecting monocytes/macrophages (sCD163, sCD14), T-cells (sCD25) and neutrophils (myeloperoxidase [MPO], neutrophil gelatinase-associated lipocalin [NGAL]) activity, could give prognostic information in precapillary PH. Circulating markers of leucocyte activation, sCD163, sCD14, sCD25, MPO and NGAL were measured by enzyme immunoassays in plasma from patients with idiopathic PAH (IPAH; n = 30); patients with PAH related to associated conditions (APAH; n = 44) and patients with chronic thromboembolic PH (CTEPH) (n = 32), and compared with 23 healthy controls. Markers of leucocyte activation were elevated in precapillary PH with particularly high levels in APAH. The elevated levels of monocyte/macrophage marker sCD163 was independently associated with poor long-term prognosis in the group as a whole, and elevated levels of sCD25 was associated with poor prognosis in APAH, while elevated levels of sCD163 and NGAL was associated with poor prognosis in IPAH and CTEPH. Our data show leucocyte activation in precapillary PH with different profiles and impact on prognosis according to etiology. The association of sCD163 with poor outcome in fully adjusted model may be of particular interest.

Mixed Venous Oxygen Saturation Is a Better Prognosticator Than Cardiac Index in Pulmonary Arterial Hypertension.

BACKGROUND: European Society of Cardiology (ESC) and European Respiratory Society (ERS) guidelines include thermodilution cardiac index (TDCI) and mixed venous oxygen saturation (SvO2) as two of the three hemodynamic determinations used in risk assessment of patients with pulmonary arterial hypertension (PAH). SvO2 may be a better measurement than TDCI to assess prognosis in patients with either idiopathic or heritable PAH. RESEARCH QUESTION: What is the concordance between TDCI and SvO2 ESC/ERS risk group allocation and their prognostic value in patients with PAH? STUDY DESIGN AND METHODS: In this retrospective study, we assessed the correlation between SvO2 and TDCI in patients with idiopathic and heritable PAH. We determined concordance in the ESC/ERS risk group allocation and association with survival, both at baseline and follow-up. RESULTS: A total of 158 patients (mean age, 58 ± 17 years; 72% women) with idiopathic (91%) and heritable (9%) PAH were included. There was moderate association between TDCI and SvO2 (r = 0.50; 95% CI, 0.37-0.62). Weighted kappa revealed a fair agreement between TDCI and SvO2 (κ = 0.30; 95% CI, 0.18-0.42), with concordance in risk group allocation in 49% of patients. During a median follow-up of 45 months (interquartile range, 23-105), 62 patients (39%) died. Using Kaplan-Meier analysis, survival was impacted by the SvO2 (log rank = 0.002) but not by the TDCI risk group allocation (log-rank = 0.51). Using the Cox proportional hazard model, adjusted for age and sex, SvO2 (but not TDCI) was associated with mortality (hazard ratio per 1% change, 0.94; 95% CI, 0.91-0.97; P < .001). INTERPRETATION: When using the cutoffs proposed by the ESC/ERS guidelines, we noted poor concordance in risk score allocation between TDCI and SvO2. In patients with idiopathic or heritable PAH, SvO2 measurements are superior to TDCI in predicting long-term mortality.

Whole-Blood RNA Profiles Associated with Pulmonary Arterial Hypertension and Clinical Outcome.

Rationale: Idiopathic and heritable pulmonary arterial hypertension (PAH) are rare but comprise a genetically heterogeneous patient group. RNA sequencing linked to the underlying genetic architecture can be used to better understand the underlying pathology by identifying key signaling pathways and stratify patients more robustly according to clinical risk.Objectives: To use a three-stage design of RNA discovery, RNA validation and model construction, and model validation to define a set of PAH-associated RNAs and a single summarizing RNA model score. To define genes most likely to be involved in disease development, we performed Mendelian randomization (MR) analysis.Methods: RNA sequencing was performed on whole-blood samples from 359 patients with idiopathic, heritable, and drug-induced PAH and 72 age- and sex-matched healthy volunteers. The score was evaluated against disease severity markers including survival analysis using all-cause mortality from diagnosis. MR used known expression quantitative trait loci and summary statistics from a PAH genome-wide association study.Measurements and Main Results: We identified 507 genes with differential RNA expression in patients with PAH compared with control subjects. A model of 25 RNAs distinguished PAH with 87% accuracy (area under the curve 95% confidence interval: 0.791-0.945) in model validation. The RNA model score was associated with disease severity and long-term survival (P = 4.66 × 10-6) in PAH. MR detected an association between SMAD5 levels and PAH disease susceptibility (odds ratio, 0.317; 95% confidence interval, 0.129-0.776; P = 0.012).Conclusions: A whole-blood RNA signature of PAH, which includes RNAs relevant to disease pathogenesis, associates with disease severity and identifies patients with poor clinical outcomes. Genetic variants associated with lower SMAD5 expression may increase susceptibility to PAH.

Nocturnal hypercapnia with daytime normocapnia in patients with advanced pulmonary arterial hypertension awaiting lung transplantation.

BACKGROUND: Pulmonary arterial hypertension (PAH) is frequently complicated by sleep disordered breathing (SDB), and previous studies have largely focused on hypoxemic SDB. Even though nocturnal hypercapnia was shown to exacerbate pulmonary hypertension, the clinical significance of nocturnal hypercapnia among PAH patients has been scarcely investigated. METHOD: Seventeen patients with PAH were identified from 246 consecutive patients referred to Kyoto University Hospital for the evaluation of lung transplant registration from January 2010 to December 2017. Included in this study were 13 patients whose nocturnal transcutaneous carbon dioxide partial pressure (PtcCO2) monitoring data were available. Nocturnal hypercapnia was diagnosed according to the guidelines of the American Academy of Sleep Medicine. Associations of nocturnal PtcCO2 measurements with clinical features, the findings of right heart catheterization and pulmonary function parameters were evaluated. RESULTS: Nocturnal hypercapnia was diagnosed in six patients (46.2%), while no patient had daytime hypercapnia. Of note, nocturnal hypercapnia was found for 5 out of 6 patients with idiopathic PAH (83.3%). Mean nocturnal PtcCO2 levels correlated negatively with the percentage of predicted total lung capacity (TLC), and positively with cardiac output and cardiac index. CONCLUSION: Nocturnal hypercapnia was prevalent among advanced PAH patients who were waiting for lung transplantation, and associated with %TLC. Nocturnal hypercapnia was associated with the increase in cardiac output, which might potentially worsen pulmonary hypertension especially during sleep. Further studies are needed to investigate hemodynamics during sleep and to clarify whether nocturnal hypercapnia can be a therapeutic target for PAH patients.

Serum human epididymis protein 4 level as a predictor of clinical worsening in idiopathic pulmonary arterial hypertension: a pilot study.

BACKGROUND: Human epididymis protein 4 (HE4) was proved to be a novel biomarker for left heart failure. The purpose of this exploratory study was to evaluate the role of HE4 in patients with idiopathic pulmonary arterial hypertension (IPAH) who usually have concurrent right heart failure. METHODS: 55 patients with newly diagnosed IPAH were continuously enrolled and serum HE4 levels were assessed at baseline. All patients were followed up from the date of blood sampling, and a composite endpoint of clinical worsening was detailedly recorded. RESULTS: Serum levels of HE4 were significantly higher in IPAH patients than healthy controls (6.9 ± 2.2 vs 4.4 ± 0.9 ng/ml, p < 0.05) and increased as cardiac function deteriorated. HE4 levels correlated with endothelin-1 (r = 0.331, p < 0.01) and right atrial pressure (r = 0.30, p < 0.03). After a mean follow-up of 20 ± 10 months, 13 patients experienced clinical worsening. Receiver operating characteristic analysis showed that HE4 levels > 6.5 ng/ml discriminated clinical worsening with a sensitivity of 92.31% and a specificity of 59.52% (area under the curve [AUC] = 0.81). Multivariate Cox regression analysis demonstrated that HE4 (χ2: 5.10; hazard ratio [HR] = 1.26; 95% confidence interval: 1.03 to 1.55, p < 0.02) and pulmonary vascular resistance (χ 2: 4.19; HR = 1.14; 95% confidence interval: 1.00-1.29, p < 0.04) were independently predictive of clinical worsening. Patients with HE4 > 6.5 ng/ml had a worse 2-year survival rate than those with HE4 ≤ 6.5 ng/ml (58.9% vs 96.2%, p < 0.001). CONCLUSIONS: Serum levels of HE4 were elevated in IPAH patients and correlated with disease severity. HE4 was an independent predictor of clinical worsening in IPAH patients.

Bone morphogenetic protein 9, and its genetic variants contribute to susceptibility of idiopathic pulmonary arterial hypertension.

Considering the predominant role of rare variants of the Bone morphogenetic protein 9 (BMP9) gene in the occurrence of idiopathic pulmonary arterial hypertension (IPAH), here we conducted a case-control study, together with functional validation, to explore the relationships between variants of the BMP9 gene and development of IPAH. We found minor alleles of rs3740297 (OR: 0.72, 95% CI: 0.59-0.87, P=7.77×10-5) and rs7923671 (OR: 0.76, 95% CI: 0.62-0.93, P=0.009) were significantly associated with decreased risk of IPAH. Minor alleles of rs3740297 and rs7923671 were significantly associated with increased plasma level of BMP9 in both IPAH cases and controls (P<0.001). An allele of rs7923671 showed higher relative luciferase activity compared to that containing G allele (P<0.001). Mechanism exploration found that pulmonary artery smooth muscle cells (PASMC) cell line transfected with rs3740297 C allele construct, miR-149 mimic, and antagomir miR-149 showed more sensitive change of the relative luciferase activity and BMP9 expression. This means minor allele T of rs3740297 could significantly decrease susceptibility of IPAH in Chinese population, possibly by increasing BMP9 expression through losing a miR-149 binding site. Our study provides evidence for genetic associations between two specific variants in the BMP9 gene and plasma level of BMP9, occurrence of IPAH.

Association Between High FSH, Low Progesterone, and Idiopathic Pulmonary Arterial Hypertension in Women of Reproductive Age.

BACKGROUND: While sex differences characterize susceptibility and severity of idiopathic pulmonary arterial hypertension (IPAH), our understanding of the relationship between levels of gonadotropins and sex hormones in fertile women and the disease is limited. We aimed to investigate whether gonadotropin and sex hormone levels in women of reproductive age were associated with risk and mortality of IPAH. METHODS: We did a matched case-control study. Cases were reproductive female patients with idiopathic pulmonary arterial hypertension admitted in Shanghai Pulmonary Hospital (Tongji University School of Medicine, Shanghai, China) during 2008-2014. Healthy controls were matched on age and body mass index. We also did a prospective cohort study to assess the effects of hormone levels on mortality in IPAH fertile female patients. RESULTS: One hundred sixty-four cases and 133 controls were included. After adjustment for age and body mass index, the odds ratios of having IPAH for follicle-stimulating hormone, testosterone, and progesterone as expressed on natural log scale were 1.51 (95% confidence interval: 1.06, 2.16), 0.42 (0.31-0.57), and 0.52 (0.43-0.63), respectively. In the cohort study with a median follow-up of 77 months, the hazard ratios for dying after adjustment for baseline characteristics and treatments among IPAH patients were 2.01 (95% confidence interval: 1.22-3.30) and 0.78 (95% confidence interval: 0.62-0.98) for follicle-stimulating hormone and progesterone in natural log scale, respectively. CONCLUSIONS: In reproductive women with IPAH, high follicle-stimulating hormone and low progesterone tended to be associated with high risk of IPAH and mortality among patients.

Circulating Plasma Metabolomic Profiles Differentiate Rodent Models of Pulmonary Hypertension and Idiopathic Pulmonary Arterial Hypertension Patients.

BACKGROUND: Pulmonary arterial hypertension (PAH) is a severe progressive disease with systemic metabolic dysregulation. Monocrotaline (MCT)-induced and hypoxia-induced pulmonary hypertension (PH) rodent models are the most widely used preclinical models, however, whether or not these preclinical models recapitulate metabolomic profiles of PAH patients remain unclear. METHODS: In this study, a targeted metabolomics panel of 126 small molecule metabolites was conducted. We applied it to the plasma of the 2 preclinical rodent models of PH and 30 idiopathic pulmonary arterial hypertension (IPAH) patients as well as 30 healthy controls to comparatively assess the metabolomic profiles of PAH patients and rodent models. RESULTS: Significantly different metabolomics profiling and pathways were shown among the 2 classical rodent models and IPAH patients. Pathway analysis demonstrated that methionine metabolism and urea cycle metabolism were the most significant pathway involved in the pathogenesis of hypoxia-induced PH model and MCT-induced model, respectively, and both of them were also observed in the dysregulated pathways in IPAH patients. CONCLUSIONS: These 2 models may develop PAH through different metabolomic pathways and each of the 2 classical PH model resembles IPAH patients in certain aspects.

Prospective Echocardiographic Evaluation of the Right Ventricle and Pulmonary Arterial Pressure in Hyperthyroid Patients.

BACKGROUND: Pulmonary arterial hypertension (PAH) occurs in 35% to 65% of hyperthyroid patients. Despite this high frequency, only a few authors have examined the effects of hyperthyroidism treatment on PAH and the right ventricle. We evaluated the effects of hyperthyroidism and its reversal on cardiovascular structure and function using Doppler echocardiography. METHODS: We prospectively evaluated 32 patients (42.5±11.9years old) with thyrotoxicosis. Exclusion criteria included previous cardiovascular disease. An echocardiogram was performed at the time of hyperthyroidism diagnosis and after normalisation of free thyroxine (T4) levels. Patients were divided into two groups according to the presence or absence of PAH at the diagnosis, or at two moments, before and after T4 normalisation. RESULTS: Graves' disease was the most frequent aetiology (75%) of hyperthyroidism. Pulmonary arterial hypertension was observed in 43.8% of patients. Free T4 concentration was higher in PAH than non-PAH patients. Free T4 normalised after 5 (2.0-10.5; median and percentiles) months of treatment. Cardiac chamber sizes and cardiac output were higher in PAH. Right ventricular (RV) systolic function was impaired in PAH. Cardiac output and free T4 (r=0.42; p<0.05) correlated with pulmonary artery systolic pressure (PASP). Cardiac chamber size, cardiac output, left ventricular ejection fraction, and PASP (34.0±8.6 to 21.7±4.5mmHg) reduced after treatment. Right ventricular myocardial performance index and fractional area change improved after T4 normalisation. CONCLUSIONS: Pulmonary arterial hypertension is highly prevalent in hyperthyroid patients and is combined with increased cardiac chambers size and cardiac output, and impaired RV function. Cardiovascular changes are reversible after T4 normalisation in patients without cardiovascular disease.

Mechanism of anti-remodelling action of treprostinil in human pulmonary arterial smooth muscle cells.

Treprostinil is applied for pulmonary arterial hypertension (PAH) therapy. However, the mechanism by which the drug achieves its beneficial effects in PAH vessels is not fully understood. This study investigated the effects of treprostinil on PDGF-BB induced remodelling parameters in isolated human pulmonary arterial smooth muscle cells (PASMC) of four PAH patients. The production of TGF-ß1, CTGF, collagen type-I and -IV, and of fibronectin were determined by ELISA and PCR. The role of cAMP was determined by ELISA and di-deoxyadenosine treatment. Proliferation was determined by direct cell count. Treprostinil increased cAMP levels dose and time dependently, which was not affected by PDGF-BB. Treprostinil significantly reduced PDGF-BB induced secretion of TGF-ß1 and CTGF, both was counteracted when cAMP generation was blocked. Similarly, the PDGF-BB induced proliferation of PASMC was dose dependently reduced by treprostinil through signalling via cAMP-C/EBP-α p42 -p21(WAf1/Cip1). In regards to extracellular matrix remodelling, treprostinil significantly reduced PDGF-BB-TGF-ß1-CTGF induced synthesis and deposition of collagen type I and fibronectin, in a cAMP sensitive manner. In contrast, the deposition of collagen IV was not affected. The data suggest that this action of treprostinil in vessel wall remodelling may benefit patients with PAH and may reduce arterial wall remodelling.

Prevalence of auto-antibodies associated to pulmonary arterial hypertension in scleroderma - A review.

The prevalence of auto-antibodies associated to pulmonary arterial hypertension in scleroderma patients was reviewed, based on reports cited in two major scientific databases. Data were collected on the following types of antibodies: antinuclear, anti-double-stranded DNA, anticentromere, anti-CENP-A, anti-CENP-B, anti-bicaudal D2, anti-nucleolar, anti-Scl-70 (anti-topoisomerase I), anti-topoisomerase II α, anti-RNP, anti-U1RNP, anti-U3RNP, anti-RNA polymerase III, anti-Th/To, anti-histone, antiphospholipid, anti-PmScl, anti-Sm, anti SSA (anti-Ro),anti SSB (La), anti-Ro52 (TRIM 21), anti-Ku, anti-B23, anti-RuvBL1, anti-RuvBL2, anti-fibrin bound tissue plasminogen activator, anti-endothelial cell, anti-phosphatidylserine-prothrombin complex, anti-endothelin-1 type A receptor, anti-angiotensin II type 1 receptor, anti­carbonic anhydrase II, anti-fibroblast, anti-cyclic citrullinated peptide, anti-4-sulfated N-Acetyl-lactosamine, class I and II anti-human leukocyte antigen. Auto-antibodies were shown by different authors to be associated to this condition, with different prevalence values for each type of auto-antibody. Antinuclear antibodies, anti-centromere antibodies, antiphospholipid antibodies, anti-U3 RNP antibodies and anti-Th/To antibodies would appear to show a particularly important prevalence in scleroderma patients with pulmonary hypertension, appearing in about 8/10 (antinuclear), 1/ 2 (anti-centromere, anti-phospholipid), and 1/4 (anti-U3RNP, anti-Th/To) of patients. The available evidence points in the direction of a strong association between auto-immune mechanisms and pulmonary hypertension in the setting of scleroderma.

Idiopathic pulmonary arterial hypertension - a unrecognized cause of high-shear high-flow haemostatic defects (otherwise referred to as acquired von Willebrand syndrome) in children.

Acquired von Willebrand syndrome (AVWS) is reported in high-flow high-shear congenital cardiac disorders. We hypothesized that the narrowed pulmonary vasculature in idiopathic pulmonary arterial hypertension (IPAH) may induce AVWS. We conducted a cross-sectional evaluation of children with IPAH. Patients with bleeding symptoms and/or laboratory abnormalities (thrombocytopenia, anomalies in coagulation screening tests) were tested in-depth for haemostatic defects. Fourteen children were followed with IPAH of which 8 were eligible. Four children exhibited abnormal bleeding scores (International Society on Thrombosis and Haemostasis Bleeding Assessment Tool: 3-5). All 8 patients showed very prolonged platelet function analyser (PFA)-100 closure times. Six children demonstrated either mild thrombocytopenia or low-normal von Willebrand factor (VWF) antigen (VWF:Ag) or VWF activity [mean (range), in iu/dl: VWF:Ag: 70 (61-91); VWF activity: 57 (34-70)]. Average VWF collagen binding capacity (VWF:CB) was 64 iu/dl (range: 53-123 iu/dl), with low-normal VWF activity/VWF:Ag or VWF:CB/VWF:Ag ratios occurring in five patients. All children had normal multimers distribution patterns. One patient underwent a lung transplantation, with normalization of haemostatic abnormalities post-surgery. Overall, 8 out of 14 children with IPAH had mild to moderate bleeding symptoms and/or laboratory abnormalities in keeping with AVWS. Normalization of the haemostatic defects following lung transplantation and lack of family history of bleeding attests to the acquired nature of their defects.

CCL21 as a Potential Serum Biomarker for Pulmonary Arterial Hypertension in Systemic Sclerosis.

OBJECTIVE: Systemic sclerosis (SSc) is a major cause of pulmonary arterial hypertension (PAH). Murine models indicate key roles for chemokines CCL19 and CCL21 and their receptor CCR7 in lung inflammation leading to PAH. The objective of this study was to assess the chemokine CCL19-CCL21 axis in patients with SSc-related PAH. METHODS: Serum samples obtained from 2 independent prospective SSc cohorts (n = 326), patients with idiopathic PAH (n = 12), and healthy control subjects (n = 100) were analyzed for CCL19/CCL21 levels, by enzyme-linked immunosorbent assay. The levels were defined as either high or low, using the mean + 2 SD value in controls as the cutoff value. Risk stratification at the time of PAH diagnosis and PAH-related events were performed. Descriptive and Cox regression analyses were conducted. RESULTS: CCL21 levels were higher in patients with SSc compared with controls and were elevated prior to the diagnosis of PAH. PAH was more frequent in patients with high CCL21 levels (≥0.4 ng/ml) than in those with low CCL21 levels (33.3% versus 5.3% [P < 0.001]). In multivariate analyses, CCL21 was associated with PAH (hazard ratio [HR] 5.1, 95% CI 2.39-10.76 [P < 0.001]) and occurrence of PAH-related events (HR 4.7, 95% CI 2.12-10.46, P < 0.001). Risk stratification at the time of PAH diagnosis alone did not predict PAH-related events. However, when risk at diagnosis was combined with high or low CCL21 level, there was a significant predictive effect (HR 1.3, 95% CI 1.03-1.60 [P = 0.027]). A high CCL21 level was associated with decreased survival (P < 0.001). CONCLUSION: CCL21 appears to be a promising marker for predicting the risk of SSc-related PAH and PAH progression. CCL21 may be part of a dysregulated immune pathway linked to the development of lung vascular damage in SSc.

Circulating plasmablasts are elevated and produce pathogenic anti-endothelial cell autoantibodies in idiopathic pulmonary arterial hypertension.

Idiopathic pulmonary arterial hypertension (IPAH) is a devastating pulmonary vascular disease in which autoimmune and inflammatory phenomena are implicated. B cells and autoantibodies have been associated with IPAH and identified as potential therapeutic targets. However, the specific populations of B cells involved and their roles in disease pathogenesis are not clearly defined. We aimed to assess the levels of activated B cells (plasmablasts) in IPAH, and to characterize recombinant antibodies derived from these plasmablasts. Blood plasmablasts are elevated in IPAH, remain elevated over time, and produce IgA autoantibodies. Single-cell sequencing of plasmablasts in IPAH revealed repertoires of affinity-matured antibodies with small clonal expansions, consistent with an ongoing autoimmune response. Recombinant antibodies representative of these clonal lineages bound known autoantigen targets and displayed an unexpectedly high degree of polyreactivity. Representative IPAH plasmablast recombinant antibodies stimulated human umbilical vein endothelial cells to produce cytokines and overexpress the adhesion molecule ICAM-1. Together, our results demonstrate an ongoing adaptive autoimmune response involving IgA plasmablasts that produce anti-endothelial cell autoantibodies in IPAH. These antibodies stimulate endothelial cell production of cytokines and adhesion molecules, which may contribute to disease pathogenesis. These findings suggest a role for mucosally-driven autoimmunity and autoimmune injury in the pathogenesis of IPAH.

Plasma proteome analysis in patients with pulmonary arterial hypertension: an observational cohort study.

BACKGROUND: Idiopathic and heritable pulmonary arterial hypertension form a rare but molecularly heterogeneous disease group. We aimed to measure and validate differences in plasma concentrations of proteins that are associated with survival in patients with idiopathic or heritable pulmonary arterial hypertension to improve risk stratification. METHODS: In this observational cohort study, we enrolled patients with idiopathic or heritable pulmonary arterial hypertension from London (UK; cohorts 1 and 2), Giessen (Germany; cohort 3), and Paris (France; cohort 4). Blood samples were collected at routine clinical appointment visits, clinical data were collected within 30 days of blood sampling, and biochemical data were collected within 7 days of blood sampling. We used an aptamer-based assay of 1129 plasma proteins, and patient clinical details were concealed to the technicians. We identified a panel of prognostic proteins, confirmed with alternative targeted assays, which we evaluated against the established prognostic risk equation for pulmonary arterial hypertension derived from the REVEAL registry. All-cause mortality was the primary endpoint. FINDINGS: 20 proteins differentiated survivors and non-survivors in 143 consecutive patients with idiopathic or heritable pulmonary arterial hypertension with 2 years' follow-up (cohort 1) and in a further 75 patients with 2·5 years' follow-up (cohort 2). Nine proteins were both prognostic independent of plasma NT-proBNP concentrations and confirmed by targeted assays. The functions of these proteins relate to myocardial stress, inflammation, pulmonary vascular cellular dysfunction and structural dysregulation, iron status, and coagulation. A cutoff-based score using the panel of nine proteins provided prognostic information independent of the REVEAL equation, improving the C statistic from area under the curve 0·83 (for REVEAL risk score, 95% CI 0·77-0·89; p<0·0001) to 0·91 (for panel and REVEAL 0·87-0·96; p<0·0001) and improving reclassification indices without detriment to calibration. Poor survival was preceded by an adverse change in panel score in paired samples from 43 incident patients with pulmonary arterial hypertension in cohort 3 (p=0·0133). The protein panel was validated in 93 patients with idiopathic or heritable pulmonary arterial hypertension in cohort 4, with 4·4 years' follow-up and improved risk estimates, providing complementary information to the clinical risk equation. INTERPRETATION: A combination of nine circulating proteins identifies patients with pulmonary arterial hypertension with a high risk of mortality, independent of existing clinical assessments, and might have a use in clinical management and the evaluation of new therapies. FUNDING: National Institute for Health Research, Wellcome Trust, British Heart Foundation, Assistance Publique-Hôpitaux de Paris, Inserm, Université Paris-Sud, and Agence Nationale de la Recherche.