Mechanical Unloading Promotes Myocardial Energy

DOI: 10.1161/CIRCGENETICS.113.000404

Mechanical Unloading Promotes Myocardial Energy Recovery in Human Heart Failure Running title: Gupte et al; Metabolism in human heart failure

Anisha A. Gupte, PhD1*; Dale J. Hamilton, MD1,2*; Andrea M. Cordero-Reyes, MD3; Keith A. Youker, PhD3; Zheng Yin, PhD4; Jerry D. Estep, MD3; Robert D. Stevens, PhD5; Brett Wenner, PhD5; Olga Ilkayeva, PhD5; Matthias Loebe, MD, PhD3; Leif E. Peterson, rson, PhD6; Christopher Christtop o J. rdd, Ph PhD D5; Guillermo Guil Gu ille il lerm le rmoo Torrerm Lyon, PhD1; Stephen T.C. Wong, PhD, PE4,7,8; Christopher B. Newgard, 11,22 Amione, MD, PhD3,9; Heinrich Taegtmeyer, MD, DPhil10; Willa lla A.. Hsueh, Hsu sueh eh,, MD1, eh

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Methodistt Di Diabetes iabetes and dM Metabolism ettab abol o issm IInstitute; ol nst sttit itutee; 4De Department epartme m ntt of of Systems S stem Sy ems Medicine Medici Me cinne and ci nd Bioengineering, Bioe io oengi ginneee 6 Center for for Biostatistics, Biostatistics, Houston Hous usston M Methodist ethodisst Res Research search h Ins Institute, sti titu tutee, Ho tu Houston, oustonn, TX X & & mp;; We mp Weill C Cornell orn n oll l eg ge, Ne N w York, York Yo rk,, N rk Y; 2De Medicall Co College, New NY; Department Depa partme m nt of me of Medicine, Medi dici c nee, 7De ci Department D part pa rtme rt m nt off Radiology, me R di Ra dioologgy, y H Houston ouust st Methodistt Hospital, Houston, & Housto ton, to n, TX &a & mp p; Weill Cornell Cornel e l Medical el Medica call College, ca Colleg ge,, Ne New York, NY; 3Meth Methodist H and Vascular Vascullar Institute, Ins n ti titu tu ute t , Houston, Hous Ho ussto ton, n, TX TX & & mp &a mp;; Weill Weeil i l Cornell Corn Co rn nel elll Medical M diica Me call College, New York, DeBakey Heart NY; 5Sarah W. Stedman Ste tedm dman dm an Nutrition Nut utri riti ri tion ti on and and Metabolism Met etab abol ab olis ol ism is m Center, Cent Ce nter nt er, an er andd De Depa Departments part pa rtme rt ment me ntss of P nt Pharmacology harm ha rmac rm acol ac olog ol ogyy and og and Cancer Biology aand Medicine, University nd Medici cine ci ne, Du ne Duke k U ke nive ni verssitty Medical ve Medi Me d ca di call Center; Cent Ce nter nt err; 8De Department Depa part rttment ntt ooff Pathology Path Pa thol th olog ol ogyy and an Laboratory Laboraat W ill Cornell C ll Medical M di l College, C ll N k NY; NY 9C Medicine, Weill New Y York, Catedra d dde C Cardiologia, di l i IInstituto i T Tecnologico 10 de Monterrey, Monterrey, Mexico; The University of Texas Medical School at Houston, Houston, TX *contributed equally

Correspondence: Willa A. Hsueh, MD Methodist Diabetes and Metabolism Institute Houston Methodist Research Institute 6550 Fannin St, Smith Tower, Suite 1001 Houston, TX 77030 Tel: 713-441-2520 Fax: 713-793-7162 E-mail: [email protected]

Journal Subject Codes: [110] Congestive, [107] Biochemistry and metabolism 1 Downloaded from http://circgenetics.ahajournals.org/ at Houston Academy of Medicine on June 3, 2016


Abstract: Background - Impaired bioenergetics is a prominent feature of the failing heart, but the underlying metabolic perturbations are poorly understood. Methods and Results - We compared metabolomic, gene transcript, and protein data from six paired failing human left ventricular (LV) tissue samples obtained during left ventricular assist device (LVAD) insertion (heart failure (HF) samples) and at heart transplant (post-LVAD samples). Non-failing left ventricular (NFLV) wall samples procured from explanted hearts of patients with right HF served as novel comparison samples. Metabolomic analyses uncovered a distinct pattern in HF tissue: 2.6 fold increased pyruvate concentrations coupled p with reduced Krebs cycle intermediates and short-chain acylcarnitines, suggesting a global glob gl obal ob al rreduction educ ed ucti uc tion ti on iin n substrate oxidation. These findings were associated with decreased transcript levels nscrip pt le leve vels ve ls ffor or eenzymes n nz that catalyze fatty regulators z fa ze fatt ttyy ac tt acid id d oxidation oxi xida xi d tion and pyruvate metabolism metaabo b lism and for key ey transcriptional regul l of mitochondrial metabolism proliferator-activated gamma ndriial metabol nd olis ol issm and an nd biogenesis, biog bi o en enes e is i , peroxisome peerooxisoome pro roli l fe feraator to or-aactiiva vate tedd re rreceptor c pt ce ptor o ga or a co-DFWLYDWRUĮPGC1A, fold DQGȖERRG, UĮ U Į PGC1 1A, 1.3 1..3 fold) folld) and andd estrogen-UHODWHGUHFHSWRUĮERRA, an esstr t og ogen--UHHODWWHGGUH U FHSSWRU ĮER UH RRA, 11.2 .2 fo fol ld DDQGȖȖE E 2.2 fold). Thus, T parallel decreases deecr crea ease ses in key ey y tra transcription ansscr c ip ption on factors fac acto ors r andd ttheir heeirr ttarget arge ar g t metabolic enzyme ge enzz genes can expl associated metabolic support eexplain p ain the decreases in associa i tedd metab boliic intermediates. i termedi in diates. Mechanical Mechhanical supp pport with pp LVAD improved metabolic prov pr rov oved ed al alll off tthese hese he se m etab et ab bol olic ic aand ndd ttranscriptional rans ra nscr crip iptiion ip onal all defects. d fe de f ct ctss. Conclusions - These observations underscore an important pathophysiologic role for severely defective metabolism in HF, while the reversibility of these defects by LVAD suggests metabolic resilience of the human heart.

Key words: heart failure, metabolism, left ventricular assist device, cardiac remodeling, mitochondria

2 Downloaded from http://circgenetics.ahajournals.org/ at Houston Academy of Medicine on June 3, 2016


Introduction Although neurohormonal blockade and mineralocorticoid antagonism have improved survival in heart failure (HF),1, 2 the five-year mortality rate of this disorder (59%) still equals that of the most common forms of cancer (58%).3 Thus, better treatments for advanced HF are urgently needed. Because multiple metabolic defects are present in the myocardium during HF, approaches that target myocardial metabolism to improve cardiac energy provision are an attractive therapeutic strategy. However, interpretation of extant human studies is complicated by difficulties associated with procuring sufficient functioning left ventricular cular ((LV) LV)) myocar myocardium rdi d u in a timely manner and with obtaining comparable non-failing LV (NFLV) V) tis tissue. i sue. IIn n th the pr present rese o we on, we performed perf pe rffor o me med metabolomic, transcriptomic transcrip pto tomic and protein n analyses analyses on rapidly aand investigation, procured NFLV pr LV and ndd ppaired aiired LV L ffrom rom m HF HF patients paatien ents ts before befoore and nd aft fteer le ft eft ven entricculaa en identically procured after left ventricular c (LVAD) ce (L LVA VAD) AD) D sup uppo port po rt. t O ur re resu sults de su ddemonstrate monstr mo t at tr ate te th that at the the metabolic mettabo me tabo b li lic alterations alte al t ratio te ons and andd assist device support. Our results y g chang ying ges in ge ggene ne exp pression th hat occur iin nH F are reversed d wi ith mechanical accompanying changes expression that HF with thhe LV. LV unloading off the

Methods Patients and Tissue Collection LV tissue was collected from 12 HF patients during LVAD insertion and from the same 12 patients at the time of LVAD removal (post-LVAD). Six of the paired samples were subjected to metabolomics, gene and protein analyses (Group 1, Table 1, Supplemental Table 1) and 6 different paired samples were subjected to transcriptomic analyses (Group 2, Supplemental Table 2). The 2 groups of patients were chosen as the first 6 available for Group 1and the next 6 available for Group 2. Pre and post-LVAD echocardiograms were interpreted in a blinded fashion by a single experienced echocardiographer (Fig. 1). LV size and systolic function were 3 Downloaded from http://circgenetics.ahajournals.org/ at Houston Academy of Medicine on June 3, 2016


defined in accord with current recommendations.4, 5 NFLV wall samples were acquired from 6 patients during heart-double lung transplantation for severe right HF (Table 1). All participants signed written informed consent approved by the Houston Methodist Hospital Institutional Review Board. Fresh tissue was obtained directly from the surgeon. Scar free, reddish LV apex samples (~2 grams) were immediately dissected and tissue was freeze-clamped in liquid nitrogen for RNA, protein and metabolomic analyses within 1-2 minutes following the hand-off. Additional sections were paraffin embedded for histology. Fibrosis measurement Masson’s trichrome richrome rich hro rome me stained sta tain ned LV sections were analyz analyzed yzed yz e by optical mi microscopy icr croscopy imaging with collagen content onteent on n (blue sta staining) ain ning) g)) expressed exp xprresssed as xp as a percentage percen pe entage ge ooff tthe he aanalyzed nalyz yzzed dL LV V ar aarea. ea. ea Metabolomic m An mic Anal Analyses alyysess al Mass spectrometry-based r rometry y-based metab metabolic bollic pprofiling rofi filiingg was usedd to measure acy fi acylcarnitines, ylcarniitines,, amino acids acc and organicc acids cid ids ((Fig (Fig. Fi 22)) as ddescribed ibed d pre previously iio sll and d as ddetailed etail iledd iinn S Supplemental pplemental pll tall M Methods. Methods eth hodd 6-8 Metabolites were correlated to echocardiographic parameters for Group 1 patients (Fig. 3). Gene and protein expression studies Quantitative real-time polymerized chain reaction (qRT-PCR) with Taqman probes and primers (Applied Biosystems) was conducted as previously described.9, 10 Candidate genes were selected based on their important metabolic function in each of the categories in Fig. 4 (A-D, F-G) such as the regulation of a rate-limiting step or master regulation of the activity of a pathway. All gene expression values were normalized against the house-keeping gene, PPIA (cyclophilin A), which revealed nearly identical expression among the 3 groups. PPIA was chosen after comparative analysis with glyceraldehyde 3-phosphate dehydrogenase (GAPDH), Actin B (ACTB), tubulin



1A (TUB1A), ribosomal gene L32 (RPL32), beta-2 microglogulin (B2M) and 18S ribosomal RNA. For protein analyses, LV tissue lysates were analyzed using standard Western blot techniques detailed in Supplementary Methods. Telomere length was measured using qRT-PCR to determine telomere repeat sequence copy number in relation to the single copy gene 36b4, as previously described.11 Microarray analyses were performed by the Genomic and RNA Profiling Core Facility of Baylor College of Medicine. RNA samples were analyzed using HG-U133 arrays scanned at 6um resolution with an Agilent G2500A Technologies Gene Array scanner. nner. The entire m microarray icro ic dataset was analyzed using Gene Set Enrichment Analysis (GSEA) v2.0.10 .0.100 software sofftware (www.broadinstitute.org/gsea/index.jsp) a ns adins nsti titu ti tute tu te.o te .or org/g /gse s a/index.jsp) 12. The G GSEA SEA was performe SE performed ed with all 186 humann Kyoto Encylopedia ylopedia of Genes yl Gen en nes and annd nd Genomes Genom mess (KEGG) (KE EGG)) ppathways ath thwa th ways too iden wa identify ntiify y gene genee fu fun function ncttionn i fi ignifi fica caant n ly enriched enr nriiche iche h d wi w th h uup-regulated p-regu gula gu late la tedd or ddown-regulated te ownn-re ow reggula re late la tedd ge te gen nes post-LVAD p st-L po LVA V D su u pathways significantly with genes support. The 12 pathways hways hway ys that chang changed ged d most si significantly ign g iffic i antlly according accorddingg to the thhe GSEA GSE EA cal calculations lculations are sh shown in Table 2. Mitochondrial DNA content and citrate synthase (CS) assay DNA was isolated from LV samples (Qiagen DNA extraction kit) and analyzed by qRT-PCR to assess the ratio of the mitochondrial-encoded NADH dehydrogenase-5 (ND5) to the nuclearencoded ȕglobin genes. CS activity, a measure of mitochondrial content, was analyzed in LV protein lysates using a microplate assay from MitoSciences (Abcam). Statistical Analysis GraphPad Prism 5.0 was used for all statistical analyses. Mann-Whitney non-parametric tests were employed to identify significant differences in mRNA expression, protein expression, and metabolomic assay differences between NFLV vs. HF (all unpaired samples). For paired HF vs.



post-LVAD samples, all differences were identified using Wilcoxon signed rank tests. Twotailed tests were performed with a significance level of D=0.05. Sample sizes for each measurement are indicated in Table 1 and figure legends. False discovery rates were determined for all acylcarnitine species, organic acids and amino acids using the Benjamini and Hochberg method.13 For the 19 acylcarnitine species significant in Figure 2 and S1, approximately 2 acylcarnitine species will be false positive at the 12.5% false discovery rate level when comparing NFLV vs. HF or HF vs. post-LVAD. Spearman rank correlation coefficients were computed between acylcarnitines, organic acids, and the patient-specific fic echocardiog echocardiography graph phyy ph parameters LV end-diastolic diameter at diastole (LVEDd) and ejection on frac fraction tion i (EF). (EF EF). ).

Results Patient Characteristics a ac arac acte teri te rist ri s iccs st a aracteristics forr NF NFLV L , Gr LV Grou oupp 1 HF and ou and ppost-LVAD ostos t LV tVAD ssubjects ubbje j ct ctss ar aree ssummarized ummarized in n Clinical characteristics NFLV, Group Table 1. These hese hes esee HF patients, pat atie ient ntss, w who ho hhad ho ad bboth othh is ot iischemic sch ch hem emic i aand ic ndd nnon-ischemic non on-is on ischemic isch chem hemic ic eetiology, tiol ti ollog ogyy, hhad ad ssignific significantly igni ig nifi ficc depressed EF and remodeling as shown by increased LVEDd. All six post-LVAD subjects received continuous-flow pumps: three received an axial flow HeartMate IITM (HM II; Thoratec Corp, Pleasanton, CA), and three received a centrifugal VentrAssistTM (VentraCore, Ltd., Australia) pump implanted as a bridge to cardiac transplantation. The median duration of LVAD support was 245.5 days (range 215-325). The HeartMate IITM operating speeds ranged from 9,000 to 10,000 rpm and VentrAssistTM from 2200 to 2400 rpm, which provided partial to full circulatory support capability. Perioperative arterial pO2 and post-operative continuous pulse oximetry did not indicate significant hypoxemia in any of the groups. NFLV samples were procured from 6 patients with severe right ventricular failure (mean age 40 years, 83% female), due to either primary or secondary pulmonary hypertension as the 6 Downloaded from http://circgenetics.ahajournals.org/ at Houston Academy of Medicine on June 3, 2016


indication for heart/lung transplant (Table 1). These LV samples had no evidence of failure based on multiple criteria: normal EF and LVEDd assessed by echocardiography (Fig. 1A), lack of fibrosis (Fig. 1B), and atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) mRNA levels generally below, and sarco/endoplasmic reticulum Ca2+-ATPase (SERCA2) mRNA levels above, HF levels (Fig. 1C). The 6 paired HF and post-LVAD and 4 of 6 NFLV samples were used for protein and metabolomics analyses, and the 6 paired samples and 6 NFLV samples were used for gene expression analyses. Medications taken include anti-hypertension drugs (angiotensin n converting enzy enzyme yme m inhibitors, beta blockers, diuretics, aldosterone antagonists), anti-atriall fibrillation fibriillattion (D (Dig (Digoxin), igox ig oxiin ox t ol (s tero sta tati tinns) ti s , anti-diabetic an (insulin), ant tii coagulants (warf far arin) and others. Deta a anti-cholesterol (statins), anti-coagulants (warfarin) Detailed foor each group upp are arre listed liste tedd in Supplemental te Suppplem menttall Table Taabl blee 11.. medicationss for a terris aract isti t cs for ti f rG fo roup ro up 2 ppatients atiients are at ar ssummarized umm mmaariz ized iz ed iinn Supplemental Supp Su pple pple l menttal al Table Tab ble l 22.. In I tthis h Clinical characteristics Group a atients th he Novacor Novacor LVAD LV VAD A (pulsatile-flow (pu p ls l atil ile-flow pu il ppumps) mp ps)) andd 3 ppatients atients received receivv the group, 3 patients received the LVAD VAD ((contin ntiin o s fflo lo ppumps), mps) s)) with iith th h a median edi dia dduration ration tii off LV LVAD AD ssupport pport rt off 54 DeBakey LV (continuous-flow 54.5 days. These 6 paired HF and post-LVAD were used for transcriptomic analyses. Metabolomic analyses reveal improved substrate utilization with LVAD Tandem mass spectrometry (MS/MS) was used to analyze acylcarnitine species ranging in size from 2 to 22 carbon atoms (Figs. 2A, S1A-B). The abundance of short- and medium-chain acylcarnitines from C2-C10 inclusively was reduced in failing versus non-failing LV samples. HF samples had reduced levels of acetylcarnitine (C2), a surrogate for acetyl-CoA, and a product of glucose, amino acid and fatty acid oxidation; propionylcarnitine (C3) and isovalerylcarnitine (C5), which derive from amino acid catabolism; and succinylcarnitine (C4-DC) and butyrylcarnitine (C4), products of amino acid and fatty acid oxidation. There was little difference



in concentrations of longer chain acylcarnitines (C14 and above) as a function of HF status. LVAD universally restored C2-C10 acylcarnitines to NFLV values, suggesting a global restoration of substrate oxidation. Several organic acids were assayed by Gas Chromatography-Mass Spectrometry as a measure of the influx of metabolic fuels into the Krebs cycle (Fig. 2B). Pyruvate levels were increased in HF samples (p