Plasma Metabolomics in Pulmonary Hypertension
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10.1161/CIRCULATIONAHA.116.024602 Plasma Metabolomics Implicate Modified Transfer RNAs and Altered Bioenergetics in the Outcome of Pulmonary Arterial Hypertension Running title: Rhodes et al.; Plasma metabolomics in pulmonary hypertension Christopher J. Rhodes, PhD1†; Pavandeep Ghataorhe, BM, BCh1†; John Wharton, PhD1; Kevin C. Rue-Albrecht, PhD1; Charaka Hadinnapola, BM, BCh2; Geoffrey Watson, BM, BCh1; Marta Bleda, PhD2; Matthias. Haimel, BSc2; Gerry Coghlan, MD3; Paul A. Corris, FRCP4; Luke. S. Howard, DPhil5,6; David G. Kiely, MD7,8; Andrew J. Peacock, MD9; Joanna Pepke-Zaba, PhD10; Mark R. Toshner, MD2,10; S. John Wort, PhD11; J. Simon R. Gibbs, MD5,6; Allan Lawrie, PhD8; Stefan Gräf, PhD2,12; Nicholas W. Morrell, MD, FMedSci2; Martin R. Wilkins, MD, FMedSci1‡ Downloaded from 1Department of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London,odo,U; UK;2Departmentepa e of o Medicine, ed c e, Un Uiversity ve s y of o Cambridge Ca b dge School Sc oo of o Clinical C ca Medicine,ed c e, Cambridge,Cambridge, UK;UK;3CardiologyCardiology Department, RoRoyalyal FreeFree HospitalHospital,, LondLondon,onn, UKUUK;; http://circ.ahajournals.org/ 4InstituteInstitute of Cellular Medicine, Newcastle UniversiUniversityty and The Newcastle uuponpon TyTynenen HHospitalsospitals NHS Foundation Trust, Newcastle upuponon Tyne,Tyne, UUK;K;5National PulmonaPulmonaryry HypertensionHypertension Service, ImperialImperial ColleCollegege HealthcarHealthcaree NH NHSS Trust,Trust, Hammersmith HoHospital,spital, London, UK; 6National Heart and Lung Institute (NHLI), Imperial College London, Hammersmith Campus, London,Londn on, UK;UKU ;7SheffieldSSheffield Pulmonary Vascular DiseaseDisease Unit, RRoyaloyo al HallamshireHallamshire Hospital, Sheffield,Sheffield, UK;UKK;8DepartmentDeD pap rtmem nt ooff InInfection,fef cttioi n, Immunitymmm unniity & CardiovascularCardioovascs ulu ar Disease,Dissease, UniversityUnU ivversityy ooff by guest on December 7, 2016 Sheffield,Shhefffield, SheffSheffield,ieeldd, UKUK;; 9ScottishScottishh PulmonaryPuulmmonaryy VascularVascuular Unit,Unnit, GoldenGoollden JubileeJubbilee NationalNatit oonall HHospital,osppittal, Glasgow,GlG asgow,, UK;UK;1010PulmonaryPulmonnara y VascularVascuulaar DiseaseDiseae see UUnit,nit, PPaaappworthwow rth HoHospital,sppitaal, Cambridge,Cambrir dgee, UK; 11PulmonaryPullmonarry HypertensionHypeertene sion Service,Serviv ce, RoyalRRoyal BromptonBrommptonn Hospital,Hoso pip tal, London,Londoon, UK;UK; 12DepartmentDepartment ofof HaHaematology,ematology, UUniverniverssityity of Cambridge,Cambrb idge, CaCambridge,mbriidge, UKUK †These authors contributed equally to this work ‡On behalf of the NIHR BioResource – Rare Diseases (BRIDGE) PAH Consortium and the UK National PAH Cohort Study Consortium Address for Correspondence: Martin R. Wilkins, MD, FMedSci Department of Medicine Imperial College London Hammersmith Campus Du Cane Road London, W12 0NN, UK Tel: 020 3313 2049 Email: [email protected], Journal Subject Terms: Biomarkers; Metabolism; Pulmonary Hypertension; Mortality/Survival; Vascular Disease 1 10.1161/CIRCULATIONAHA.116.024602 Abstract Background— Pulmonary arterial hypertension (PAH) is a heterogeneous disorder with high mortality. Methods—We conducted a comprehensive study of plasma metabolites using ultra-performance liquid chromatography mass-spectrometry to (1) identify patients at high risk of early death, (2) identify patients who respond well to treatment and (3) provide novel molecular insights into disease pathogenesis. Results— 53 circulating metabolites distinguished well-phenotyped patients with idiopathic or heritable PAH (n=365) from healthy controls (n=121) following correction for multiple testing (p<7.3e-5) and confounding factors, including drug therapy, renal and hepatic impairment. A subset of 20/53 metabolites also discriminated PAH patients from disease controls (symptomatic patients without pulmonary hypertension, n=139). 62 metabolites were prognostic in PAH, with 36/62 independent of established prognostic markers. Increased levels of tRNA-specific Downloaded from modified nucleosides (N2,N2-dimethylguanosine, N1-methylinosine), TCA cycle intermediates (malate, fumarate), glutamate, fatty acid acylcarnitines, tryptophan and polyamine metabolites and decreased levels of steroids, sphingomyelins and phosphatidylcholines distinguished patients fromocoos. controls. Thee largestagest differencesd e e ces cocorrelated e a ed wwith increasedc eased risk s of o death dea ad andd cocorrection ec o oof severaleveral mmetabolitesetabolites oveoverr timtimee wwasas aassociatedssociated wwithith a betterbetter ououtcome.tcome. Patients whwhoo respondedreesponded to http://circ.ahajournals.org/ ccalciumalcium channel blocker thertherapyapy had metabolic prprofilesofiles similar to healthhealthyy controcontrols.lss. CConclusions—onclusions— Metabolic profilesprofiles in PAH are stronglystrongly related to survival and should be cconsideredonsidered ppartart of the deedeepp phphenotypicenotypic chacharacteracteririsationsation ofof thisthis disease.disease. Our results supportsupport the investigationnvestigation of ttargetedargeted therapeutic strategies that seek to address thethe alterationsalterations in translationaltranslational regulationegulation aandnd eenergyneerrgy mmetabolismetabolism that charactericharacterisese these patientpatients.s. by guest on December 7, 2016 KeKey-words:y-words: mmetabolome;etaaboloomme; memetabolomics;taboloomim cs; memetabolism;tabbolism; pupulmonarylmmonary cicirculation;rcculu attion; ppulmonaryullmmonaary hhypertensionypertr ension 2 10.1161/CIRCULATIONAHA.116.024602 Clinical Perspective What is new? x This study provides a comprehensive analysis of circulating metabolite levels in patients with pulmonary arterial hypertension (PAH) and controls. x It is the first to relate metabolite levels to clinical outcomes in PAH. x Increases in circulating modified nucleosides originating from transfer RNAs, energy metabolism intermediates, tryptophan and polyamine metabolites, and decreased steroids, sphingomyelins and phosphatidylcholines independently discriminate PAH patients from Downloaded from controls and predict survival. x Correction of metabolite levels over time is linked to better clinical outcomes and patients who respond well to calcium-channel blocker therapy have metabolic profiles http://circ.ahajournals.org/ comparablecomparable with healthy controls.controls. WhatWhat aarere the clinical implications? x EnergyEnE ergy mmetabolismeetaba olism and stress-responsstress-responsee papathwaysathways are disdisturbedturbr edd iinn PAH.PAH. by guest on December 7, 2016 x MonitoringMonitoriingg pplasmalaasma metabolitesmetabolitet s thattthat reportreppoort ono thesethese pathwayspaathwwaya s overover timetime couldcoulu d be usefuluseeful toto assess diseasedisi ease pprogressionrogrresssion and rresponseeesponsse too ttherapy.heerapy. x TherapeuticTherapep utic sstrategiestrata egies tatargetedrgeted aagainstgainnst mmeettabolictaba olic disturbancesdistuurbannces inn PPAH,AH, particularlyparticuulara ly translationalli l regulation li andd energy metabolism,bli meritif further h iinvestigation i i 3 10.1161/CIRCULATIONAHA.116.024602 Introduction Pulmonary arterial hypertension (PAH) is a progressive vascular disorder that leads to increased pulmonary vascular resistance, right ventricular (RV) dysfunction 1 and premature death 2. The pathogenesis of the vascular pathology is poorly understood 3, 4. Several genetic mutations have been reported in hereditary and isolated idiopathic presentations of PAH, providing insight into perturbed signalling pathways 5, 6, and genome sequencing of clinically well characterised patient cohorts is underway in anticipation of finding new mutations. A complementary approach to Downloaded from identifying the molecular drivers of PAH is to conduct deep molecular phenotyping of patients beyond standard clinical tests. MMetabolomicetabolomic technologies, such as ultra-performanceultra-performance liquid chrochromatographymatography massmass sspectrometry,pectroomettry http://circ.ahajournals.org/ eenablenable ththee dedetectiontection anandd sesemi-quantitativemi-quantitative measurementmeasurement of hundreds of uniuniqueque metabolites, representingepresenting a broad range of metabolic pathways,pathways, in smallsmall volumes of biofluids 7. TheseThese approachesapprp ooaches hhaveavve ididentifieddene tit fied ddifferencesiffereences iinn circcirculatingulating memetabolitestat bolil tees ththathat ddistinguishistinguish pphysiologicalhysis ologo icala by guest on December 7, 2016 aandnd ddidiseasesease ststates,aatees, ssusuchch as didiabetesaba etes aandndd ssystemicystemim c cacardiovascularrddiovav sscular ddisorders,iisorders, aanandd prpredicteddiict cclclinicalinicaal ououtcomestcomes 8-108-1010. As yetyet,, fewfef w metabolomicsmetabolol mics studiesstudies hahaveve bebeenen uundertakennddertaken ini patients wiwiththh pulmonary vascular disease. Evidence of abnormal oxidation, arginine and sphingosine pathways have been found from mass spectrometry analysis of lung tissue from PAH patients 11, 12 and analysis of breath samples showed exhaled volatile compounds discriminate between severe idiopathic PAH and healthy volunteers 13. A targeted analysis of 105 circulating plasma metabolites in PAH, primarily amino acids, nucleosides and their derivatives, showed abnormal levels of tryptophan, purine and tricarboxylic acid cycle metabolites correlated to haemodynamic