Publications
245 results found
Woolf B, Perry JA, Hong CC, et al., 2024, Multi-biobank summary data Mendelian randomisation does not support a causal effect of IL-6 signalling on risk of pulmonary arterial hypertension., Eur Respir J, Vol: 63
In the most comprehensive analysis to date, this study failed to detect an association of genetically predicted CRP-weighted IL-6 signalling or CRP-weighted IL-6R signalling with PAH risk using all available PAH GWAS data https://bit.ly/3T5h5uj
Alhathli E, Julian T, Girach ZUA, et al., 2024, Mendelian randomization study with clinical follow-up links metabolites to risk and severity of pulmonary arterial hypertension, Journal of the American Heart Association, Vol: 13, ISSN: 2047-9980
BACKGROUND: Pulmonary arterial hypertension (PAH) exhibits phenotypic heterogeneity and variable response to therapy. The metabolome has been implicated in the pathogenesis of PAH, but previous works have lacked power to implicate specific metabolites. Mendelian randomization (MR) is a method for causal inference between exposures and outcomes. METHODS AND RESULTS: Using genome-wide association study summary statistics, we implemented MR analysis to test for potential causal relationships between serum concentration of 575 metabolites and PAH. Five metabolites were causally associated with the risk of PAH after multiple testing correction. Next, we measured serum concentration of candidate metabolites in an independent clinical cohort of 449 patients with PAH to check whether metabolite concentrations are correlated with markers of disease severity. Of the 5 candidates nominated by our MR work, serine was negatively associated and homostachydrine was positively associated with clinical severity of PAH via direct measurement in this independent clinical cohort. Finally we used conditional and orthogonal approaches to explore the biology underlying our lead metabolites. Rare variant burden testing was carried out using whole exome sequencing data from 578 PAH cases and 361 675 controls. Multivariable MR is an extension of MR that uses a single set of instrumental single-nucleotide polymorphisms to measure multiple exposures; multivariable MR is used to determine interdependence between the effects of different exposures on a single outcome. Rare variant analysis demonstrated that loss-of-function mutations within activating transcription factor 4, a transcription factor responsible for upregulation of serine synthesis under conditions of serine starvation, are associated with higher risk for PAH. Homostachydrine is a xenobiotic metabolite that is structurally related to l-proline betaine, which has previously been linked to modulation of inflammation and tissue
Liley J, Newnham M, Bleda M, et al., 2024, Shared and distinct genomics of chronic thromboembolic pulmonary hypertension and pulmonary embolism, American Journal of Respiratory and Critical Care Medicine, ISSN: 1073-449X
Rationale: Chronic Thromboembolic Pulmonary Hypertension involves formation and non-resolution of thrombus, dysregulated inflammation, angiogenesis and the development of a small vessel vasculopathy. Objectives: We aimed to establish the genetic basis of chronic thromboembolic pulmonary hypertension to gain insight into its pathophysiological contributors. Methods: We conducted a genome-wide association study on 1907 European cases and 10363 European controls. We co-analysed our results with existing results from genome-wide association studies on deep vein thrombosis, pulmonary embolism and idiopathic pulmonary arterial hypertension. Measurements and Main Results: Our primary association study revealed genetic associations at the ABO, FGG, F11, MYH7B, and HLA-DRA loci. Through our co-analysis we demonstrate further associations with chronic thromboembolic pulmonary hypertension at the F2, TSPAN15, SLC44A2 and F5 loci but find no statistically significant associations shared with idiopathic pulmonary arterial hypertension. Conclusions: Chronic thromboembolic pulmonary hypertension is a partially heritable polygenic disease, with related though distinct genetic associations to pulmonary embolism and to deep vein thrombosis.
Tai Y-Y, Yu Q, Tang Y, et al., 2024, Allele-specific control of rodent and human lncRNA KMT2E-AS1 promotes hypoxic endothelial pathology in pulmonary hypertension., Sci Transl Med, Vol: 16
Hypoxic reprogramming of vasculature relies on genetic, epigenetic, and metabolic circuitry, but the control points are unknown. In pulmonary arterial hypertension (PAH), a disease driven by hypoxia inducible factor (HIF)-dependent vascular dysfunction, HIF-2α promoted expression of neighboring genes, long noncoding RNA (lncRNA) histone lysine N-methyltransferase 2E-antisense 1 (KMT2E-AS1) and histone lysine N-methyltransferase 2E (KMT2E). KMT2E-AS1 stabilized KMT2E protein to increase epigenetic histone 3 lysine 4 trimethylation (H3K4me3), driving HIF-2α-dependent metabolic and pathogenic endothelial activity. This lncRNA axis also increased HIF-2α expression across epigenetic, transcriptional, and posttranscriptional contexts, thus promoting a positive feedback loop to further augment HIF-2α activity. We identified a genetic association between rs73184087, a single-nucleotide variant (SNV) within a KMT2E intron, and disease risk in PAH discovery and replication patient cohorts and in a global meta-analysis. This SNV displayed allele (G)-specific association with HIF-2α, engaged in long-range chromatin interactions, and induced the lncRNA-KMT2E tandem in hypoxic (G/G) cells. In vivo, KMT2E-AS1 deficiency protected against PAH in mice, as did pharmacologic inhibition of histone methylation in rats. Conversely, forced lncRNA expression promoted more severe PH. Thus, the KMT2E-AS1/KMT2E pair orchestrates across convergent multi-ome landscapes to mediate HIF-2α pathobiology and represents a key clinical target in pulmonary hypertension.
Ulrich A, Wu Y, Draisma H, et al., 2024, Blood DNA methylation profiling identifies cathepsin Z dysregulation in pulmonary arterial hypertension, Nature Communications, Vol: 15, ISSN: 2041-1723
Pulmonary arterial hypertension (PAH) is characterised by pulmonary vascular remodelling causing premature death from right heart failure. Established DNA variants influence PAH risk, but susceptibility from epigenetic changes is unknown. We addressed this through epigenome-wide association study (EWAS), testing 865,848 CpG sites for association with PAH in 429 individuals with PAH and 1226 controls. Three loci, at Cathepsin Z (CTSZ, cg04917472), Conserved oligomeric Golgi complex 6 (COG6, cg27396197), and Zinc Finger Protein 678 (ZNF678, cg03144189), reached epigenome-wide significance (p < 10−7) and are hypermethylated in PAH, including in individuals with PAH at 1-year follow-up. Of 16 established PAH genes, only cg10976975 in BMP10 shows hypermethylation in PAH. Hypermethylation at CTSZ is associated with decreased blood cathepsin Z mRNA levels. Knockdown of CTSZ expression in human pulmonary artery endothelial cells increases caspase-3/7 activity (p < 10−4). DNA methylation profiles are altered in PAH, exemplified by the pulmonary endothelial function modifier CTSZ, encoding protease cathepsin Z.
Walters R, Vasilaki E, Wilkins MR, et al., 2023, Response by Walters et al to Letter Regarding Article, "SOX17 Enhancer Variants Disrupt Transcription Factor Binding and Enhancer Inactivity Drives Pulmonary Hypertension"., Circulation, Vol: 148, Pages: 1825-1826
Welch CL, Aldred MA, Balachandar S, et al., 2023, Defining the clinical validity of genes reported to cause pulmonary arterial hypertension, Genetics in Medicine, Vol: 25, ISSN: 1098-3600
PURPOSE: Pulmonary arterial hypertension (PAH) is a rare, progressive vasculopathy with significant cardiopulmonary morbidity and mortality. Genetic testing is currently recommended for adults diagnosed with heritable, idiopathic, anorexigen-, hereditary hemorrhagic telangiectasia-, and congenital heart disease-associated PAH, PAH with overt features of venous/capillary involvement, and all children diagnosed with PAH. Variants in at least 27 genes have putative evidence for PAH causality. Rigorous assessment of the evidence is needed to inform genetic testing. METHODS: An international panel of experts in PAH applied a semi-quantitative scoring system developed by the NIH Clinical Genome Resource to classify the relative strength of evidence supporting PAH gene-disease relationships based on genetic and experimental evidence. RESULTS: Twelve genes (BMPR2, ACVRL1, ATP13A3, CAV1, EIF2AK4, ENG, GDF2, KCNK3, KDR, SMAD9, SOX17, and TBX4) were classified as having definitive evidence and 3 genes (ABCC8, GGCX, and TET2) with moderate evidence. Six genes (AQP1, BMP10, FBLN2, KLF2, KLK1, and PDGFD) were classified as having limited evidence for causal effects of variants. TOPBP1 was classified as having no known PAH relationship. Five genes (BMPR1A, BMPR1B, NOTCH3, SMAD1, and SMAD4) were disputed because of a paucity of genetic evidence over time. CONCLUSION: We recommend that genetic testing includes all genes with definitive evidence and that caution be taken in the interpretation of variants identified in genes with moderate or limited evidence. Genes with no known evidence for PAH or disputed genes should not be included in genetic testing.
Guignabert C, Savale L, Boucly A, et al., 2023, Serum and Pulmonary Expression Profiles of the Activin Signaling System in Pulmonary Arterial Hypertension, CIRCULATION, Vol: 147, Pages: 1809-1822, ISSN: 0009-7322
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- Citations: 4
Walters R, Vasilaki E, Aman J, et al., 2023, SOX17 enhancer variants disrupt transcription factor binding and enhancer inactivity drives pulmonary hypertension, Circulation, Vol: 147, Pages: 1606-1621, ISSN: 0009-7322
BACKGROUND: Pulmonary arterial hypertension (PAH) is a rare disease characterized by remodeling of the pulmonary arteries, increased vascular resistance, and right-sided heart failure. Genome-wide association studies of idiopathic/heritable PAH established novel genetic risk variants, including conserved enhancers upstream of transcription factor (TF) SOX17 containing 2 independent signals. SOX17 is an important TF in embryonic development and in the homeostasis of pulmonary artery endothelial cells (hPAEC) in the adult. Rare pathogenic mutations in SOX17 cause heritable PAH. We hypothesized that PAH risk alleles in an enhancer region impair TF-binding upstream of SOX17, which in turn reduces SOX17 expression and contributes to disturbed endothelial cell function and PAH development. METHODS: CRISPR manipulation and siRNA were used to modulate SOX17 expression. Electromobility shift assays were used to confirm in silico-predicted TF differential binding to the SOX17 variants. Functional assays in hPAECs were used to establish the biological consequences of SOX17 loss. In silico analysis with the connectivity map was used to predict compounds that rescue disturbed SOX17 signaling. Mice with deletion of the SOX17-signal 1 enhancer region (SOX17-4593/enhKO) were phenotyped in response to chronic hypoxia and SU5416/hypoxia. RESULTS: CRISPR inhibition of SOX17-signal 2 and deletion of SOX17-signal 1 specifically decreased SOX17 expression. Electromobility shift assays demonstrated differential binding of hPAEC nuclear proteins to the risk and nonrisk alleles from both SOX17 signals. Candidate TFs HOXA5 and ROR-α were identified through in silico analysis and antibody electromobility shift assays. Analysis of the hPAEC transcriptomes revealed alteration of PAH-relevant pathways on SOX17 silencing, including extracellular matrix regulation. SOX17 silencing in hPAECs resulted in increased apoptosis, proliferation, and disturbance of barrier function. With the use of t
Guignabert C, Savale L, Boucly A, et al., 2023, Associations Between Serum Activin A and Follistatine-Like 3 Levels and Outcomes in Pulmonary Arterial Hypertension, International Conference of the American-Thoracic-Society (ATS), Publisher: AMER THORACIC SOC, ISSN: 1073-449X
Boucly A, Tu L, Guignabert C, et al., 2023, Cytokines as Prognostic Biomarkers in Pulmonary Arterial Hypertension, International Conference of the American-Thoracic-Society (ATS), Publisher: AMER THORACIC SOC, ISSN: 1073-449X
Hirsch K, Nolley S, Ralph DD, et al., 2023, Circulating markers of inflammation and angiogenesis and clinical outcomes across subtypes of pulmonary arterial hypertension, JOURNAL OF HEART AND LUNG TRANSPLANTATION, Vol: 42, ISSN: 1053-2498
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- Citations: 4
Ali MK, Tian X, Zhao L, et al., 2023, PTPN1 Deficiency Modulates BMPR2 Signaling and Induces Endothelial Dysfunction in Pulmonary Arterial Hypertension, CELLS, Vol: 12
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- Citations: 1
Aman J, Morrell NW, Rhodes CJ, et al., 2022, The SOX17 phenotype in pulmonary arterial hypertension: lessons for pathobiology and clinical management, European Respiratory Journal, Vol: 60, ISSN: 0903-1936
Worldwide collaborative efforts to understand the genetic architecture of pulmonary arterial hypertension (PAH) have identified several gene variants and mutations in the past 5 years. With subsequent deep phenotyping, the clinical picture associated with these mutations is becoming more clear. For example, following the identification of pathogenic mutations in TBX4 and KDR [1, 2], histopathological and clinical phenotypes were described, with specific characteristics like small patella and bronchial diverticulosis for TBX4 and low diffusing capacity of the lung for carbon monoxide and interstitial changes for KDR [3–5]. Just as mutations identify key players in pathophysiology, the clinical and histopathological characterisation of mutation carriers provides insights into the cellular processes involved.
Kariotis S, Jammeh E, Swietlik EM, et al., 2022, Biological heterogeneity in idiopathic pulmonary arterial hypertension identified through unsupervised transcriptomic profiling of whole blood, Nature Communications, Vol: 13, Pages: 1-1, ISSN: 2041-1723
Wojciak-Stothard B, Ainscough AJ, Smith TJ, et al., 2022, An organ-on-chip model of pulmonary arterial hypertension identifies a BMPR2-SOX17-prostacyclin signalling axis, Communications Biology, Vol: 5, Pages: 1-15, ISSN: 2399-3642
Pulmonary arterial hypertension (PAH) is an unmet clinical need. The lack of models of human disease is a key obstacle to drug development. We present a biomimetic model of pulmonary arterial endothelial-smooth muscle cell interactions in PAH, combining natural and induced bone morphogenetic protein receptor 2 (BMPR2) dysfunction with hypoxia to induce smooth muscle activation and proliferation, which is responsive to drug treatment. BMPR2- and oxygenation-specific changes in endothelial and smooth muscle gene expression, consistent with observations made in genomic and biochemical studies of PAH, enable insights into underlying disease pathways and mechanisms of drug response. The model captures key changes in the pulmonary endothelial phenotype that are essential for the induction of SMC remodelling, including a BMPR2-SOX17-prostacyclin signalling axis and offers an easily accessible approach for researchers to study pulmonary vascular remodelling and advance drug development in PAH.
Constantine A, Rhodes CJ, Ricci P, et al., 2022, Correlation between right ventricular dysfunction and plasma protein profile in pulmonary hypertension, Publisher: EUROPEAN RESPIRATORY SOC JOURNALS LTD, ISSN: 0903-1936
Selle J, Dinger K, Jentgen V, et al., 2022, Maternal and perinatal obesity induce bronchial obstruction and pulmonary hypertension via IL-6-FoxO1-axis in later life, NATURE COMMUNICATIONS, Vol: 13
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- Citations: 4
Jones RJ, De Bie EMDD, Groves E, et al., 2022, Autoimmunity is a significant feature of idiopathic pulmonary arterial hypertension., American Journal of Respiratory and Critical Care Medicine, Vol: 206, Pages: 81-93, ISSN: 1073-449X
RATIONALE: Autoimmunity is thought to play a role in idiopathic pulmonary arterial hypertension (IPAH). It is not clear if this is causative or a bystander of disease and if it carries any prognostic or treatment significance. OBJECTIVE: To study autoimmunity in IPAH using a large cross-sectional cohort. METHODS: Assessment of the circulating immune cell phenotype was undertaken using flow cytometry and the profile of serum immunoglobulins was generated using a standardised multiplex array of 19 clinically validated autoantibodies in 473 cases and 946 controls. Additional GST-fusion array and ELISA data were used to identify a serum autoantibody to BMPR2. Clustering analyses and clinical correlations were employed to determine associations between immunogenicity and clinical outcomes. MEASUREMENTS AND MAIN RESULTS: Flow cytometric immune profiling demonstrates IPAH is associated with an altered humoral immune response in addition to raised IgG3. Multiplexed autoantibodies were significantly raised in IPAH, and clustering demonstrated three distinct clusters: 'high autoantibody', 'low autoantibody', and a small 'intermediate' cluster exhibiting high levels of RNP-complex. The high autoantibody cluster had worse haemodynamics but improved survival. A small subset of patients demonstrated immunoglobulin reactivity to BMPR2. CONCLUSIONS: This study establishes aberrant immune regulation and presence of autoantibodies as a key feature in the profile of a significant proportion of IPAH patients and is associated with clinical outcomes. This article is open access and distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/).
Toshner M, Church C, Harbaum L, et al., 2022, Mendelian randomisation and experimental medicine approaches to interleukin-6 as a drug target in pulmonary arterial hypertension (vol 59, 2002463, 2022), EUROPEAN RESPIRATORY JOURNAL, Vol: 60, ISSN: 0903-1936
Errington N, Kariotis S, Jammeh E, et al., 2022, Unsupervised Clustering of PH Using Circulating miRNA - Towards Molecular Classification of PH?, International Conference of the American-Thoracic-Society, Publisher: AMER THORACIC SOC, ISSN: 1073-449X
Rhodes C, Wharton J, Swietlik E, et al., 2022, Using the plasma proteome for risk stratifying patients with pulmonary arterial hypertension, American Journal of Respiratory and Critical Care Medicine, Vol: 205, Pages: 1102-1111, ISSN: 1073-449X
Rationale: N-terminal pro-brain natriuretic peptide (NT-proBNP), a biomarker of cardiac origin, is used to risk stratify patients with pulmonary arterial hypertension (PAH). Its limitations include poor sensitivity to early vascular pathology. Other biomarkers of vascular or systemic origin may also be useful in the management of PAH.Objectives: Identify prognostic proteins in PAH which complement NT-proBNP and clinical risk scores.Methods: An aptamer-based assay (SomaScan-V4) targeting 4,152 proteins was used to measure plasma proteins in patients with idiopathic, heritable or drug-induced-PAH from the UK National Cohort of PAH (n=357) and the French EFORT study (n=79). Prognostic proteins were identified in discovery-replication analyses of UK samples. Proteins independent of 6-minute walk distance (6-MWD) and NT-proBNP entered LASSO modelling and the best combination in a single score was evaluated against clinical targets in EFORT.Measurements and Main Results: Thirty-one proteins robustly informed prognosis independent of NT-proBNP and 6-MWD in the UK Cohort. A weighted combination score of 6 proteins was validated at baseline (5-year mortality, AUC:0.73, 95%CI:0.63-0.85) and follow-up in EFORT (AUC:0.84, 95%CI:0.75-0.94, p=9.96x10-6). The protein score risk-stratified patients independent of established clinical targets and risk equations. The addition of the 6-protein model score to NT-proBNP improved prediction of 5-year outcomes from AUC:0.762 (0.702-0.821) to 0.818 (0.767-0.869) by ROC analysis (p=0.00426 for difference in AUC) in the UK replication and French samples combined. Conclusions: The plasma proteome informs prognosis beyond established factors in PAH and may provide a more sensitive measure of therapeutic response.
Kariotis S, Jammeh E, Swietlik EM, et al., 2022, Longitudinal Analysis of Three Major Risk-Associated Transcriptomic Subgroups Within the IPAH Classification, International Conference of the American-Thoracic-Society, Publisher: AMER THORACIC SOC, ISSN: 1073-449X
Rhodes CJ, Sweatt AJ, Maron BA, 2022, Harnessing Big Data to Advance Treatment and Understanding of Pulmonary Hypertension, CIRCULATION RESEARCH, Vol: 130, Pages: 1423-1444, ISSN: 0009-7330
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- Citations: 9
Harbaum L, Rhodes CJ, Wharton J, et al., 2022, Mining the plasma proteome for insights into the molecular pathology of pulmonary arterial hypertension., American Journal of Respiratory and Critical Care Medicine, Vol: 205, Pages: 1-12, ISSN: 1073-449X
RATIONALE: Pulmonary arterial hypertension (PAH) is characterized by structural remodelling of pulmonary arteries and arterioles. Underlying biological processes are likely reflected in a perturbation of circulating proteins. OBJECTIVES: To quantify and analyse the plasma proteome of PAH patients using inherited genetic variation to inform on underlying molecular drivers. METHODS: An aptamer-based assay was used to measure plasma proteins in 357 patients with idiopathic or heritable PAH, 103 healthy volunteers and 23 relatives of PAH patients. In discovery and replication subgroups, the plasma proteomes of PAH and healthy individuals were compared and the relationship to transplantation-free survival in PAH determined. To examine causal relationships to PAH, protein quantitative trait loci (pQTL) that influenced protein levels in the patient population were used as instruments for Mendelian randomisation (MR) analysis. MEASUREMENTS AND MAIN RESULTS: From 4,152 annotated plasma proteins, levels of 208 differed between PAH patients and healthy subjects and 49 predicted long-term survival. MR based on cis-pQTL located in proximity to the encoding gene for proteins that were prognostic and distinguished PAH from health estimated an adverse effect for higher levels of netrin-4 (odds ratio [OR] 1.55, 95%-confidence interval [CI] 1.16-2.08) and a protective effect for higher levels of thrombospondin-2 (OR 0.83, 95%-CI 0.74-0.94) on PAH. Both proteins tracked the development of PAH in previously healthy relatives and changes in thrombospondin-2 associated with pulmonary arterial pressure at disease onset. CONCLUSIONS: Integrated analysis of the plasma proteome and genome implicates two secreted matrix-binding proteins, netrin-4 and thrombospondin-2, in the pathobiology of PAH.
Howard LSGE, He J, Watson GMJ, et al., 2022, Supplementation with Iron in Pulmonary Arterial Hypertension: Two Randomized Crossover Trials (vol 18, pg 981, 2021), ANNALS OF THE AMERICAN THORACIC SOCIETY, Vol: 19, Pages: 703-703, ISSN: 1546-3222
Boucly A, Tu L, Guignabert C, et al., 2022, Cytokines as prognostic biomarkers in pulmonary arterial hypertension, European Respiratory Journal, Vol: 61, ISSN: 0903-1936
INTRODUCTION: Risk stratification and assessment of disease progression in patients with pulmonary arterial hypertension (PAH) are challenged by the lack of accurate disease-specific and prognostic biomarkers. To date, B-type natriuretic peptide (BNP) and/or its N-terminal fragment (NT-proBNP) are the only marker for right ventricular dysfunction used in clinical practice, in association with echocardiographic and invasive hemodymamic variables to predict outcome in patients with PAH. METHODS: This study was designed to identify an easily measurable biomarker panel in the serum of 80 well-phenotyped PAH patients with idiopathic, heritable, or drug-induced PAH at baseline and first follow-up. The prognostic value of identified cytokines of interest was secondly analysed in an external validation cohort of 125 PAH patients. RESULTS: Among the 20 biomarkers studied with the multiplex EllaTM platform, we identified a 3-biomarker panel composed of ß-NGF, CXCL9 and TRAIL that were independently associated with prognosis both at the time of PAH diagnosis and at the first follow-up after initiation of PAH therapy. β-NGF and CXCL9 were predictors of death or transplantation, whereas high levels of TRAIL were associated with a better prognosis. Furthermore, prognostic value of the three cytokines was more powerful for predicting survival than usual non-invasive variables (functional class, 6-minute walking distance and BNP/NT-proBNP). The results were validated in a fully independent external validation cohort. CONCLUSION: The monitoring of ß-NGF, CXCL9 and TRAIL levels in serum should be considered in the management and treatment of patients with PAH to objectively guide therapeutic options.
Constantine A, Rhodes CJ, Ricci P, et al., 2022, PLASMA PROTEIN PROFILE IN EISENMENGER SYNDROME AND OTHER FORMS OF PH: ASSOCIATION WITH MARKERS OF RV REMODELLING, ACC.22, Publisher: ELSEVIER SCIENCE INC, Pages: 1364-1364, ISSN: 0735-1097
Kariotis S, Jammeh E, Swietlik EM, et al., 2021, Biological heterogeneity in idiopathic pulmonary arterial hypertension identified through unsupervised transcriptomic profiling of whole blood, Nature Communications, Vol: 12, Pages: 1-14, ISSN: 2041-1723
Idiopathic pulmonary arterial hypertension (IPAH) is a rare but fatal disease diagnosed by right heart catheterisation and the exclusion of other forms of pulmonary arterial hypertension, producing a heterogeneous population with varied treatment response. Here we show unsupervised machine learning identification of three major patient subgroups that account for 92% of the cohort, each with unique whole blood transcriptomic and clinical feature signatures. These subgroups are associated with poor, moderate, and good prognosis. The poor prognosis subgroup is associated with upregulation of the ALAS2 and downregulation of several immunoglobulin genes, while the good prognosis subgroup is defined by upregulation of the bone morphogenetic protein signalling regulator NOG, and the C/C variant of HLA-DPA1/DPB1 (independently associated with survival). These findings independently validated provide evidence for the existence of 3 major subgroups (endophenotypes) within the IPAH classification, could improve risk stratification and provide molecular insights into the pathogenesis of IPAH.
Sweatt AJ, Miyagawa K, Rhodes CJ, et al., 2021, Severe pulmonary arterial hypertension is characterized by increased neutrophil elastase and relative elafin deficiency, Chest, Vol: 160, Pages: 1442-1458, ISSN: 0012-3692
BACKGROUND: Preclinical evidence implicates neutrophil elastase (NE) in PAH pathogenesis, and the NE inhibitor elafin is under early therapeutic investigation. RESEARCH QUESTION: Are circulating NE and elafin levels abnormal in PAH and associated with clinical severity? STUDY DESIGN/METHODS: . In an observational Stanford University PAH cohort (N=249), plasma NE and elafin were measured in comparison to healthy controls (N=106) then related to clinical features and relevant ancillary biomarkers. Cox regression models were fitted with cubic spline functions to associate NE and elafin with survival. To validate prognostic relationships, we analyzed two United Kingdom cohorts (N=75, N=357). Mixed effects models evaluated NE and elafin changes during disease progression. Finally, we studied effects of NE/elafin balance on pulmonary artery endothelial cells (PAECs) from PAH patients. RESULTS: Relative to controls, patients had increased NE (205.1 [123.6-387.3] vs. 97.6 [74.4-126.6] ng/mL, P<0.0001) and decreased elafin (32.0 [15.3-59.1] vs. 45.5 [28.1-92.8] ng/mL, P<0.0001) independent of PAH subtype, illness duration, and therapies. Higher NE associated with worse symptom severity, shorter six-minute walk distance, higher NT-proBNP, greater right ventricular dysfunction, worse hemodynamics, increased circulating neutrophils, elevated cytokine levels, and lower blood BMPR2 expression. In Stanford patients, NE>168.5 ng/mL portended increased mortality risk after adjustment for known clinical predictors (HR 2.52, CI 1.36-4.65, P=0.003) or prognostic cytokines (HR 2.63, CI 1.42-4.87, P=0.001), and NE added incremental value to established PAH risk scores. Similar prognostic thresholds were identified in validation cohorts. Longitudinal NE changes tracked with clinical trends and outcomes. PAH-PAECs exhibited increased apoptosis and attenuated angiogenesis when exposed to NE at the level observed in patients' blood. Elafin rescued PAEC homeostasis, yet the required
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