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Kolb TM, Johnston L, Damarla M, Kass DA, Hassoun PM. PDE9A deficiency does not prevent chronic-hypoxic pulmonary hypertension in mice. Physiol Rep 2021; 9:e15057. [PMID: 34569183 PMCID: PMC8474007 DOI: 10.14814/phy2.15057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 09/03/2021] [Accepted: 09/04/2021] [Indexed: 12/31/2022] Open
Abstract
Inhibition of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterases (PDEs) is a cornerstone of pulmonary arterial hypertension (PAH)-specific therapy. PDE9A, expressed in the heart and lung tissue, has the highest affinity for cGMP of all known PDEs. PDE9A deficiency protects mice against chronic left ventricular (LV) pressure overload via increased natriuretic peptide (NP)-dependent cGMP signaling. Chronic-hypoxic pulmonary hypertension (CH-PH) is a model of chronic right ventricular (RV) pressure overload, and previous studies have demonstrated a protective role for NPs in the murine model. Therefore, we hypothesized that PDE9A deficiency would promote NP-dependent cGMP signaling and prevent RV remodeling in the CH-PH model, analogous to findings in the LV. We exposed wild-type and PDE9A-deficient (Pde9a-/- ) C57BL/6 mice to CH-PH for 3 weeks. We measured RV pressure, hypertrophy, and levels of lung and RV cGMP, PDE9A, PDE5A, and phosphorylation of the protein kinase G substrate VASP (vasodilatory-stimulated phosphoprotein) after CH-PH. In wild-type mice, CH-PH was associated with increased circulating ANP and lung PDE5A, but no increase in cGMP, PDE9A, or VASP phosphorylation. Downstream effectors of cGMP were not increased in Pde9a-/- mice exposed to CH-PH compared with Pde9a+/+ littermates, and CH-PH induced increases in RV pressure and hypertrophy were not attenuated in knockout mice. Taken together, these findings argue against a prominent role for PDE9A in the murine CH-PH model.
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Hassan HJ, Housten T, Balasubramanian A, Simpson CE, Damico RL, Mathai SC, Hassoun PM, Steppan J, Leary PJ, Kolb TM. A novel approach to perioperative risk assessment for patients with pulmonary hypertension. ERJ Open Res 2021; 7:00257-2021. [PMID: 34291108 PMCID: PMC8287131 DOI: 10.1183/23120541.00257-2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 05/02/2021] [Indexed: 11/06/2022] Open
Abstract
Rationale Pulmonary hypertension (PH) is associated with significant perioperative morbidity and mortality. We hypothesised that pulmonary arterial hypertension (PAH) composite risk assessment scores could estimate perioperative risk for PH patients when adjusted for inherent procedural risk. Methods We identified patients in the Johns Hopkins PH Center Registry that had noncardiac surgery (including endoscopies) between September 2015 and January 2020. We collected information on preoperative patient-level and procedural variables and used logistic regression to evaluate associations with a composite outcome of death within 30 days or serious postoperative complication. We generated composite patient-level risk assessment scores for each subject and used logistic regression to estimate the association with adverse surgical outcomes. We adjusted multivariable models for inherent procedural risk of major cardiovascular events and used these models to generate a numerical PH perioperative risk (PHPR) score. Results Among 150 subjects, 19 (12.7%) reached the primary outcome, including 7 deaths (4.7%). Individual patient-level and procedural variables were associated with the primary outcome (all p<0.05). A composite patient-level risk assessment score built on three noninvasive parameters was strongly associated with reduced risk for poor outcomes (OR=0.4, p=0.03). This association was strengthened after adjusting the model for procedural risk. A PHPR score derived from the multivariable model stratified patients into low (0%), intermediate (≤10%), or high (>10%) risk of reaching the primary outcome. Conclusion Composite PAH risk assessment scores can predict perioperative risk for PH patients after accounting for inherent procedural risk. Validation of the PHPR score in a multicentre, prospective cohort is warranted. For patients with pulmonary hypertension undergoing noncardiac surgery, perioperative risk can be estimated using a model that combines inherent procedural risk with composite PAH risk assessment scoreshttps://bit.ly/3uTCibP
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Ambade AS, Hassoun PM, Damico RL. Basement Membrane Extracellular Matrix Proteins in Pulmonary Vascular and Right Ventricular Remodeling in Pulmonary Hypertension. Am J Respir Cell Mol Biol 2021; 65:245-258. [PMID: 34129804 DOI: 10.1165/rcmb.2021-0091tr] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The extracellular matrix (ECM), a highly organized network of structural and non-structural proteins, plays a pivotal role in cellular and tissue homeostasis. Changes in the ECM are critical for normal tissue repair, while dysregulation contributes to aberrant tissue remodeling. Pulmonary arterial hypertension (PAH) is a severe disorder of the pulmonary vasculature characterized by pathologic remodeling of the pulmonary vasculature and right ventricle (RV), increased production and deposition of structural and non-structural proteins, and altered expression of ECM growth factors and proteases. Furthermore, ECM remodeling plays a significant role in disease progression as several dynamic changes in its composition, quantity, and organization are documented in both humans and animal models of disease. These ECM changes impact upon vascular cell biology and affect proliferation of resident cells. Further, ECM components determine the tissue architecture of the pulmonary and myocardial vasculature as well as the myocardium itself, and provide mechanical stability crucial for tissue homeostasis. However, little is known about the basement membrane (BM), a specialized, self-assembled conglomerate of ECM proteins, during remodeling. In the vasculature, the BM is in close physical association with the vascular endothelium and smooth muscle cells. While in the myocardium, each cardiomyocyte is enclosed by a BM that serves as the interface between cardiomyocytes and the surrounding interstitial matrix. In this review, we provide a brief overview on the current state of knowledge of the BM and its ECM composition and their impact on pulmonary vascular remodeling and RV dysfunction and failure in PAH.
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Leopold JA, Kawut SM, Aldred MA, Archer SL, Benza RL, Bristow MR, Brittain EL, Chesler N, DeMan FS, Erzurum SC, Gladwin MT, Hassoun PM, Hemnes AR, Lahm T, Lima JA, Loscalzo J, Maron BA, Rosa LM, Newman JH, Redline S, Rich S, Rischard F, Sugeng L, Tang WHW, Tedford RJ, Tsai EJ, Ventetuolo CE, Zhou Y, Aggarwal NR, Xiao L. Diagnosis and Treatment of Right Heart Failure in Pulmonary Vascular Diseases: A National Heart, Lung, and Blood Institute Workshop. Circ Heart Fail 2021; 14:e007975. [PMID: 34422205 PMCID: PMC8375628 DOI: 10.1161/circheartfailure.120.007975] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Right ventricular dysfunction is a hallmark of advanced pulmonary vascular, lung parenchymal, and left heart disease, yet the underlying mechanisms that govern (mal)adaptation remain incompletely characterized. Owing to the knowledge gaps in our understanding of the right ventricle (RV) in health and disease, the National Heart, Lung, and Blood Institute (NHLBI) commissioned a working group to identify current challenges in the field. These included a need to define and standardize normal RV structure and function in populations; access to RV tissue for research purposes and the development of complex experimental platforms that recapitulate the in vivo environment; and the advancement of imaging and invasive methodologies to study the RV within basic, translational, and clinical research programs. Specific recommendations were provided, including a call to incorporate precision medicine and innovations in prognosis, diagnosis, and novel RV therapeutics for patients with pulmonary vascular disease.
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Naranjo M, Hassoun PM. Systemic Sclerosis-Associated Pulmonary Hypertension: Spectrum and Impact. Diagnostics (Basel) 2021; 11:911. [PMID: 34065226 PMCID: PMC8161029 DOI: 10.3390/diagnostics11050911] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 04/12/2021] [Accepted: 04/12/2021] [Indexed: 12/14/2022] Open
Abstract
Systemic sclerosis-associated pulmonary arterial hypertension (SSc-PAH) is a catastrophic complication of one of the most common and devastating autoimmune diseases. Once diagnosed, it becomes the leading cause of mortality among this patient population. Screening modalities and risk assessments have been designed and validated by various organizations and societies in order to identify patients early in their disease course and promptly refer them to expert centers for a hemodynamic assessment and formal diagnosis. Moreover, several large multicenter clinical trials have now included patients with SSc-PAH to assess their response to therapy. Despite an improved understanding of the condition and significant advances in supportive and targeted therapy, outcomes have remained far from optimal. Therefore, rigorous phenotyping and search for novel therapies are desperately needed for this devastating condition.
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Mukherjee M, Mercurio V, Hsu S, Mayer SA, Mathai SC, Hummers LK, Kass DA, Hassoun PM, Wigley FM, Tedford RJ, Shah AA. Assessment of right ventricular reserve utilizing exercise provocation in systemic sclerosis. Int J Cardiovasc Imaging 2021; 37:2137-2147. [PMID: 33860914 DOI: 10.1007/s10554-021-02237-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 04/03/2021] [Indexed: 01/28/2023]
Abstract
Right ventricular (RV) capacity to adapt to increased afterload is the main determinant of outcome in pulmonary hypertension, a common morbidity seen in systemic sclerosis (SSc). We hypothesized that supine bicycle echocardiography (SBE), coupled with RV longitudinal systolic strain (RVLSS), improves detection of limitations in RV reserve in SSc. 56 SSc patients were prospectively studied during SBE with RV functional parameters compared at rest and peak stress. We further dichotomized patients based on resting RV systolic pressure (RVSP) to determine the effects of load on contractile response. Our pooled cohort analysis revealed reduced global RVLSS at rest (-16.2 ± 3.9%) with normal basal contractility (-25.6 ± 7.7%) and relative hypokinesis of the midventricular (-14.1 ± 6.0%) and apical (-8.9 ± 5.1%) segments. With exercise, global RVLSS increased significantly (p = 0.0005), however despite normal basal contractility at rest, there was no further augmentation with exercise. Mid and apical RVLSS increased with exercise suggestive of RV contractile reserve. In patients with resting RVSP < 35 mmHg, global and segmental RVLSS increased with exercise. In patients with resting RVSP ≥ 35 mmHg, global and segmental RVLSS did not increase with exercise and there was evidence of exertional RV dilation. Exercise provocation in conjunction with RVLSS identified differential regional contractile response to exercise in SSc patients. We further demonstrate the effect of increased loading conditions on RV contractile response exercise. These findings suggest subclinical impairments in RV reserve in SSc that may be missed by resting noninvasive 2DE-based assessments alone.
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Mercurio V, Cuomo A, Naranjo M, Hassoun PM. Inflammatory Mechanisms in the Pathogenesis of Pulmonary Arterial Hypertension: Recent Advances. Compr Physiol 2021; 11:1805-1829. [PMID: 33792903 DOI: 10.1002/cphy.c200025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Inflammatory processes are increasingly recognized in the pathogenesis of the vascular remodeling that characterizes pulmonary arterial hypertension (PAH). Chronic inflammation may contribute to disease progression or serve as a biomarker of PAH severity. Furthermore, inflammatory pathways may represent possible therapeutic targets for novel PAH-specific drugs beyond the currently approved therapies targeting the endothelin, nitric oxide/cyclic GMP, and prostacyclin biological pathways. The main focus of this article is to provide recent advances in the understanding of the role of inflammatory pathways in the pathogenesis of PAH from preclinical studies and current clinical data supporting chronic inflammation in PAH patients and to discuss emerging therapeutic implications. © 2021 American Physiological Society. Compr Physiol 11:1805-1829, 2021.
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Zamanian RT, Badesch D, Chung L, Domsic RT, Medsger T, Pinckney A, Keyes-Elstein L, D'Aveta C, Spychala M, White RJ, Hassoun PM, Torres F, Sweatt AJ, Molitor JA, Khanna D, Maecker H, Welch B, Goldmuntz E, Nicolls MR. Safety and Efficacy of B-Cell Depletion with Rituximab for the Treatment of Systemic Sclerosis-associated Pulmonary Arterial Hypertension: A Multicenter, Double-Blind, Randomized, Placebo-controlled Trial. Am J Respir Crit Care Med 2021; 204:209-221. [PMID: 33651671 PMCID: PMC8650794 DOI: 10.1164/rccm.202009-3481oc] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Rationale: Systemic sclerosis (SSc)-pulmonary arterial hypertension (PAH) is one of the most prevalent and deadly forms of PAH. B cells may contribute to SSc pathogenesis. Objectives: We investigated the safety and efficacy of B-cell depletion for SSc-PAH. Methods: In an NIH-sponsored, multicenter, double-blinded, randomized, placebo-controlled, proof-of-concept trial, 57 patients with SSc-PAH on stable-dose standard medical therapy received two infusions of 1,000 mg rituximab or placebo administered 2 weeks apart. The primary outcome measure was the change in 6-minute-walk distance (6MWD) at 24 weeks. Secondary endpoints included safety and invasive hemodynamics. We applied a machine learning approach to predict drug responsiveness. Measurements and Main Results: We randomized 57 subjects from 2010 to 2018. In the primary analysis, using data through Week 24, the adjusted mean change in 6MWD at 24 weeks favored the treatment arm but did not reach statistical significance (23.6 ± 11.1 m vs. 0.5 ± 9.7 m; P = 0.12). Although a negative study, when data through Week 48 were also considered, the estimated change in 6MWD at Week 24 was 25.5 ± 8.8 m for rituximab and 0.4 ± 7.4 m for placebo (P = 0.03). Rituximab treatment appeared to be safe and well tolerated. Low levels of RF (rheumatoid factor), IL-12, and IL-17 were sensitive and specific as favorable predictors of a rituximab response as measured by an improved 6MWD (receiver operating characteristic area under the curve, 0.88-0.95). Conclusions: B-cell depletion therapy is a potentially effective and safe adjuvant treatment for SSc-PAH. Future studies in these patients can confirm whether the identified biomarkers predict rituximab responsiveness. Clinical trial registered with www.clinicaltrails.gov (NCT01086540).
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Ireland CG, Damico RL, Kolb TM, Mathai SC, Mukherjee M, Zimmerman SL, Shah AA, Wigley FM, Houston BA, Hassoun PM, Kass DA, Tedford RJ, Hsu S. Exercise right ventricular ejection fraction predicts right ventricular contractile reserve. J Heart Lung Transplant 2021; 40:504-512. [PMID: 33752973 DOI: 10.1016/j.healun.2021.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 01/08/2021] [Accepted: 02/04/2021] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Right ventricular (RV) contractile reserve shows promise as an indicator of occult RV dysfunction in pulmonary vascular disease. We investigated which measure of RV contractile reserve during exercise best predicts occult RV dysfunction and clinical outcomes. METHODS We prospectively studied RV contractile reserve in 35 human subjects referred for right heart catheterization for known or suspected pulmonary hypertension. All underwent cardiac magnetic resonance imaging, echocardiography, and supine invasive cardiopulmonary exercise testing with concomitant RV pressure-volume catheterization. Event-free survival was prospectively adjudicated from time of right heart catheterization for a 4-year follow-up period. RESULTS RV contractile reserve during exercise, as measured by a positive change in end-systolic elastance (Ees) during exertion, was associated with elevation in pulmonary pressures but preservation of RV volumes. Lack of RV reserve, on the other hand, was tightly coupled with acute RV dilation during exertion (R2 = 0.76, p< 0.001). RV Ees and dilation changes each predicted resting RV-PA dysfunction. RV ejection fraction during exercise, which captured exertional changes in both RV Ees and RV dilation, proved to be a robust surrogate for RV contractile reserve. Reduced exercise RV ejection fraction best predicted occult RV dysfunction among a variety of resting and exercise RV measures, and was also associated with clinical worsening. CONCLUSIONS RV ejection fraction during exercise, as an index of RV contractile reserve, allows for excellent identification of occult RV dysfunction, more so than resting measures of RV function, and may predict clinical outcomes as well.
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Khural JS, Houston BA, Leary PJ, Mathai SC, Kolb TM, Damico R, Hassoun PM, Kass DA, Hsu S, Tedford RJ. Right Atrial Pacing to Improve Acute Hemodynamics in Pulmonary Arterial Hypertension. Am J Respir Crit Care Med 2021; 203:508-511. [PMID: 33026819 PMCID: PMC7885846 DOI: 10.1164/rccm.202006-2278le] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Alkhunaizi FA, Harowicz MR, Ireland CG, Houston BA, Damico RL, Kolb TM, Mathai SC, Zimmerman SL, Hassoun PM, Tedford RJ, Hsu S. Kussmaul's Sign in Pulmonary Hypertension Corresponds With Severe Pulmonary Vascular Pathology Rather Than Right Ventricular Diastolic Dysfunction. Circ Heart Fail 2021; 14:e007461. [PMID: 33356363 PMCID: PMC7855096 DOI: 10.1161/circheartfailure.120.007461] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Thenappan T, Al-Naamani N, Ghio S, Ghofrani HA, Hassoun PM, Pritzker M, Torbicki A, Nikkho S, Busse D, Preston IR. Effect of riociguat on pulmonary arterial compliance in the PATENT and CHEST studies. Pulm Circ 2020; 10:2045894020963836. [PMID: 33282192 PMCID: PMC7686638 DOI: 10.1177/2045894020963836] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 08/30/2020] [Indexed: 01/19/2023] Open
Abstract
Pulmonary arterial compliance is a measure of the pulsatile afterload of the
right ventricle. Lower pulmonary arterial compliance is associated with reduced
right ventricular function and worse prognosis in pulmonary hypertension. The
effect of pulmonary vasodilators on pulmonary arterial compliance has not been
evaluated in detail in pulmonary arterial hypertension or chronic thromboembolic
pulmonary hypertension. In this post hoc analysis of patients with pulmonary
arterial hypertension and chronic thromboembolic pulmonary hypertension in the
PATENT and CHEST studies, we evaluated the change in pulmonary arterial
compliance with riociguat versus placebo. Association of pulmonary arterial
compliance with clinical outcomes was assessed using Kaplan–Meier and Cox
proportional hazards analyses. Compared with placebo, riociguat significantly
improved pulmonary arterial compliance in patients with pulmonary arterial
hypertension or chronic thromboembolic pulmonary hypertension. Pulmonary
arterial compliance at baseline was associated with survival and clinical
worsening-free survival in pulmonary arterial hypertension but only with
clinical worsening-free survival in chronic thromboembolic pulmonary
hypertension. In patients with pulmonary arterial hypertension, pulmonary
arterial compliance at follow-up ≥1.6 mL/mmHg was associated with better
outcomes than pulmonary arterial compliance <1.6 mL/mmHg. In patients with
chronic thromboembolic pulmonary hypertension, pulmonary arterial compliance at
follow-up did not predict outcomes. Cox proportional hazards analyses showed no
association between change in pulmonary arterial compliance and outcomes in
patients with pulmonary arterial hypertension or chronic thromboembolic
pulmonary hypertension. In conclusion, riociguat improved pulmonary arterial
compliance in patients with pulmonary arterial hypertension or chronic
thromboembolic pulmonary hypertension. Pulmonary arterial compliance at baseline
or follow-up, rather than change in pulmonary arterial compliance, is of
prognostic importance for outcomes.
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Yang J, Griffiths M, Nies MK, Brandal S, Damico R, Vaidya D, Tao X, Simpson CE, Kolb TM, Mathai SC, Pauciulo MW, Nichols WC, Ivy DD, Austin ED, Hassoun PM, Everett AD. Insulin-like growth factor binding protein-2: a new circulating indicator of pulmonary arterial hypertension severity and survival. BMC Med 2020; 18:268. [PMID: 33019943 PMCID: PMC7537100 DOI: 10.1186/s12916-020-01734-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 08/05/2020] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Pulmonary arterial hypertension (PAH) is a fatal disease that results from cardio-pulmonary dysfunction with the pathology largely unknown. Insulin-like growth factor binding protein 2 (IGFBP2) is an important member of the insulin-like growth factor family, with evidence suggesting elevation in PAH patients. We investigated the diagnostic and prognostic value of serum IGFBP2 in PAH to determine if it could discriminate PAH from healthy controls and if it was associated with disease severity and survival. METHODS Serum IGFBP2 levels, as well as IGF1/2 levels, were measured in two independent PAH cohorts, the Johns Hopkins Pulmonary Hypertension program (JHPH, N = 127), NHLBI PAHBiobank (PAHB, N = 203), and a healthy control cohort (N = 128). The protein levels in lung tissues were determined by western blot. The IGFBP2 mRNA expression levels in pulmonary artery smooth muscle cells (PASMC) and endothelial cells (PAEC) were assessed by RNA-seq, secreted protein levels by ELISA. Association of biomarkers with clinical variables was evaluated using adjusted linear or logistic regression and Kaplan-Meier analysis. RESULTS In both PAH cohorts, serum IGFBP2 levels were significantly elevated (p < 0.0001) compared to controls and discriminated PAH from controls with an AUC of 0.76 (p < 0.0001). A higher IGFBP2 level was associated with a shorter 6-min walk distance (6MWD) in both cohorts after adjustment for age and sex (coefficient - 50.235 and - 57.336 respectively). Cox multivariable analysis demonstrated that higher serum IGFBP2 was a significant independent predictor of mortality in PAHB cohort only (HR, 3.92; 95% CI, 1.37-11.21). IGF1 levels were significantly increased only in the PAHB cohort; however, neither IGF1 nor IGF2 had equivalent levels of associations with clinical variables compared with IGFBP2. Western blotting shown that IGFBP2 protein was significantly increased in the PAH vs control lung tissues. Finally, IGFBP2 mRNA expression and secreted protein levels were significantly higher in PASMC than in PAEC. CONCLUSIONS IGFBP2 protein expression was increased in the PAH lung, and secreted by PASMC. Elevated circulating IGFBP2 was associated with PAH severity and mortality and is a potentially valuable prognostic marker in PAH.
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Mercurio V, Diab N, Peloquin G, Housten-Harris T, Damico R, Kolb TM, Mathai SC, Hassoun PM. Risk assessment in Scleroderma-associated pulmonary arterial hypertension. Vascul Pharmacol 2020. [DOI: 10.1016/j.vph.2020.106738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Ghio S, Mercurio V, Fortuni F, Forfia PR, Gall H, Ghofrani A, Mathai SC, Mazurek JA, Mukherjee M, Richter M, Scelsi L, Hassoun PM, Tello K. A comprehensive echocardiographic method for risk stratification in pulmonary arterial hypertension. Eur Respir J 2020; 56:13993003.00513-2020. [PMID: 32430422 DOI: 10.1183/13993003.00513-2020] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 05/07/2020] [Indexed: 02/01/2023]
Abstract
QUESTION ADDRESSED Echocardiography is not currently considered as providing sufficient prognostic information to serve as an integral part of treatment goals in pulmonary arterial hypertension (PAH). We tested the hypothesis that incorporation of multiple parameters reflecting right heart function would improve the prognostic value of this imaging modality. METHODS AND MAIN RESULTS We pooled individual patient data from a total of 517 patients (mean age 52±15 years, 64.8% females) included in seven observational studies conducted at five European and United States academic centres. Patients were subdivided into three groups representing progressive degrees of right ventricular dysfunction based on a combination of echocardiographic measurements, as follows. Group 1 (low risk): normal tricuspid annular plane systolic excursion (TAPSE) and nonsignificant tricuspid regurgitation (TR) (n=129); group 2 (intermediate risk): normal TAPSE and significant TR or impaired TAPSE and nondilated inferior vena cava (IVC) (n=256); group 3 (high risk): impaired TAPSE and dilated IVC (n=132). The 5-year cumulative survival rate was 82% in group 1, 63% in group 2 and 43% in group 3. Low-risk patients had better survival rates than intermediate-risk patients (log-rank Chi-squared 12.25; p<0.001) and intermediate-risk patients had better survival rates than high-risk patients (log-rank Chi-squared 26.25; p<0.001). Inclusion of other parameters such as right atrial area and pericardial effusion did not provide added prognostic value. ANSWER TO THE QUESTION The proposed echocardiographic approach integrating the evaluation of TAPSE, TR grade and IVC is effective in stratifying the risk for all-cause mortality in PAH patients, outperforming the prognostic parameters suggested by current guidelines.
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Metkus TS, Mathai SC, Leucker T, Hassoun PM, Tedford RJ, Korley FK. Pulmonary and systemic hemodynamics are associated with myocardial injury in the acute respiratory distress syndrome. Pulm Circ 2020; 10:2045894020939846. [PMID: 32754308 PMCID: PMC7378723 DOI: 10.1177/2045894020939846] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 06/15/2020] [Indexed: 11/25/2022] Open
Abstract
Background Whether right and left heart hemodynamics are associated with myocardial
injury in the acute respiratory distress syndrome (ARDS) is not known. Methods We performed a retrospective cohort study of subjects who had right heart
catheterization within the ALVEOLI trial and Fluid and Catheter Treatment
Trial. Myocardial injury was assessed using a highly sensitive troponin
assay (hsTn; Abbot ARCHITECT). Hemodynamic variables included right atrial
pressure, pulmonary artery wedge pressure, cardiac index and stroke volume,
pulmonary vascular resistance, pulmonary arterial compliance, and pulmonary
effective arterial elastance. We performed linear, logistic, and Cox
regression to determine the association of hemodynamic variables with
myocardial injury and to determine if hemodynamics mediated the association
between myocardial injury and death. Results Among 252 ARDS patients, median day 0 troponin was 65.4 (13.8–397.8) ng/L.
Lower cardiac index (β −0.23 SE 0.10; P < 0.001) and stroke volume (β
−0.26 SE 0.005; P < 0.001), higher pulmonary vascular resistance (β 0.22
SE 0.11; P < 0.001), lower pulmonary arterial compliance (β −0.24 SE
0.06; P < 0.001), and higher arterial elastance (β 0.27 SE 0.43;
P < 0.001) were associated with greater myocardial injury in univariable
and adjusted models. Changes in stroke volume, cardiac index, pulmonary
arterial compliance, pulmonary vascular resistance, and arterial elastance
were all associated with progressive myocardial injury over three days. hsTn
levels were associated with mortality; however, the association was
attenuated after adjustment for each of stroke volume, pulmonary vascular
resistance, pulmonary arterial compliance, and arterial elastance. Conclusion Pulmonary vascular hemodynamics are associated with myocardial injury in
ARDS, while filling pressures are not. Pulmonary vascular disease may
represent a treatable contributor to myocardial injury in ARDS.
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Hsu S, Simpson CE, Houston BA, Wand A, Sato T, Kolb TM, Mathai SC, Kass DA, Hassoun PM, Damico RL, Tedford RJ. Multi-Beat Right Ventricular-Arterial Coupling Predicts Clinical Worsening in Pulmonary Arterial Hypertension. J Am Heart Assoc 2020; 9:e016031. [PMID: 32384024 PMCID: PMC7660856 DOI: 10.1161/jaha.119.016031] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 04/17/2020] [Indexed: 11/16/2022]
Abstract
Background Although right ventricular (RV) to pulmonary arterial (RV-PA) coupling is considered the gold standard in assessing RV dysfunction, its ability to predict clinically significant outcomes is poorly understood. We assessed the ability of RV-PA coupling, determined by the ratio of multi-beat (MB) end-systolic elastance (Ees) to effective arterial elastance (Ea), to predict clinical outcomes. Methods and Results Twenty-six subjects with pulmonary arterial hypertension (PAH) underwent same-day cardiac magnetic resonance imaging, right heart catheterization, and RV pressure-volume assessment with MB determination of Ees/Ea. RV ejection fraction (RVEF), stroke volume/end-systolic volume, and single beat-estimated Ees/Ea were also determined. Patients were treated with standard therapies and followed prospectively until they met criteria of clinical worsening (CW), as defined by ≥10% decline in 6-minute walk distance, worsening World Health Organization (WHO) functional class, PAH therapy escalation, RV failure hospitalization, or transplant/death. Subjects were 57±14 years, largely WHO class III (50%) at enrollment, with preserved average RV ejection fraction (RVEF) (47±11%). Mean follow-up was 3.2±1.3 years. Sixteen (62%) subjects met CW criteria. MB Ees/Ea was significantly lower in CW subjects (0.7±0.5 versus 1.3±0.8, P=0.02). The optimal MB Ees/Ea cut-point predictive of CW was 0.65, defined by ROC (AUC 0.78, P=0.01). MB Ees/Ea below this cut-point was significantly associated with time to CW (hazard ratio 5.1, P=0.001). MB Ees/Ea remained predictive of outcomes following multivariate adjustment for timing of PAH diagnosis and PAH diagnosis subtype. Conclusions RV-PA coupling as measured by MB Ees/Ea has prognostic significance in human PAH, even in a cohort with preserved RVEF.
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Simpson CE, Chen JY, Damico RL, Hassoun PM, Martin LJ, Yang J, Nies M, Griffiths M, Vaidya RD, Brandal S, Pauciulo MW, Lutz KA, Coleman AW, Austin ED, Ivy DD, Nichols WC, Everett AD. Cellular sources of interleukin-6 and associations with clinical phenotypes and outcomes in pulmonary arterial hypertension. Eur Respir J 2020; 55:13993003.01761-2019. [PMID: 32029443 DOI: 10.1183/13993003.01761-2019] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 01/18/2020] [Indexed: 12/31/2022]
Abstract
The pro-inflammatory cytokine interleukin (IL)-6 has been associated with outcomes in small pulmonary arterial hypertension (PAH) cohorts composed largely of patients with severe idiopathic PAH (IPAH). It is unclear whether IL-6 is a marker of critical illness or a mechanistic biomarker of pulmonary vascular remodelling. We hypothesised that IL-6 is produced by pulmonary vascular cells and sought to explore IL-6 associations with phenotypes and outcomes across diverse subtypes in a large PAH cohort.IL-6 protein and gene expression levels were measured in cultured pulmonary artery smooth muscle cells (PASMCs) and endothelial cells (PAECs) from PAH patients and healthy controls. Serum IL-6 was measured in 2017 well-characterised PAH subjects representing each PAH subgroup. Relationships between IL-6 levels, clinical variables, and mortality were analysed using regression models.Significantly higher IL-6 protein and gene expression levels were produced by PASMCs than by PAECs in PAH (p<0.001), while there was no difference in IL-6 between cell types in controls. Serum IL-6 was highest in PAH related to portal hypertension and connective tissue diseases (CTD-PAH). In multivariable modelling, serum IL-6 was associated with survival in the overall cohort (hazard ratio 1.22, 95% CI 1.08-1.38; p<0.01) and in IPAH, but not in CTD-PAH. IL-6 remained associated with survival in low-risk subgroups of subjects with mild disease.IL-6 is released from PASMCs, and circulating IL-6 is associated with specific clinical phenotypes and outcomes in various PAH subgroups, including subjects with less severe disease. IL-6 is a mechanistic biomarker, and thus a potential therapeutic target, in certain PAH subgroups.
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Hassoun PM. Early Detection of Pulmonary Vascular Dysfunction in Neonatal Bronchopulmonary Dysplasia. Am J Respir Crit Care Med 2020; 201:7-9. [PMID: 31658423 PMCID: PMC6938142 DOI: 10.1164/rccm.201910-1993ed] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Goyanes AM, Moldobaeva A, Marimoutou M, Varela LC, Wang L, Johnston LF, Aladdin MM, Peloquin GL, Kim BS, Damarla M, Suresh K, Sato T, Kolb TM, Hassoun PM, Damico RL. Functional Impact of Human Genetic Variants of COL18A1/Endostatin on Pulmonary Endothelium. Am J Respir Cell Mol Biol 2020; 62:524-534. [PMID: 31922883 PMCID: PMC7110972 DOI: 10.1165/rcmb.2019-0056oc] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 01/08/2020] [Indexed: 12/22/2022] Open
Abstract
Pulmonary arterial hypertension (PAH) is an incurable disease characterized by disordered and dysfunctional angiogenesis leading to small-vessel loss and an obliterative vasculopathy. The pathogenesis of PAH is not fully understood, but multiple studies have demonstrated links between elevated angiostatic factors, disease severity, and adverse clinical outcomes. ES (endostatin), one such circulating angiostatic peptide, is the cleavage product of the proteoglycan COL18A1 (collagen α1[XVIII] chain). Elevated serum ES is associated with increased mortality and disease severity in PAH. A nonsynonymous variant of ES (aspartic acid-to-asparagine substitution at amino acid 104; p.D104N) is associated with differences in PAH survival. Although COL18A1/ES expression is markedly increased in remodeled pulmonary vessels in PAH, the impact of ES on pulmonary endothelial cell (PEC) biology and molecular contributions to PAH severity remain undetermined. In the present study, we characterized the effects of exogenous ES on human PEC biology and signaling. We demonstrated that ES inhibits PEC migration, proliferation, and cell survival, with significant differences between human variants, indicating that they are functional genetic variants. ES promotes proteasome-mediated degradation of the transcriptional repressor ID1, increasing expression and release of TSP-1 (thrombospondin 1). ES inhibits PEC migration via an ID1/TSP-1/CD36-dependent pathway, in contrast to proliferation and apoptosis, which require both CD36 and CD47. Collectively, the data implicate ES as a novel negative regulator of ID1 and an upstream propagator of an angiostatic signal cascade converging on CD36 and CD47, providing insight into the cellular and molecular effects of a functional genetic variant linked to altered outcomes in PAH.
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Potus F, Pauciulo MW, Cook EK, Zhu N, Hsieh A, Welch CL, Shen Y, Tian L, Lima P, Mewburn J, D'Arsigny CL, Lutz KA, Coleman AW, Damico R, Snetsinger B, Martin AY, Hassoun PM, Nichols WC, Chung WK, Rauh MJ, Archer SL. Novel Mutations and Decreased Expression of the Epigenetic Regulator TET2 in Pulmonary Arterial Hypertension. Circulation 2020; 141:1986-2000. [PMID: 32192357 DOI: 10.1161/circulationaha.119.044320] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND Pulmonary arterial hypertension (PAH) is a lethal vasculopathy. Hereditary cases are associated with germline mutations in BMPR2 and 16 other genes; however, these mutations occur in <25% of patients with idiopathic PAH and are rare in PAH associated with connective tissue diseases. Preclinical studies suggest epigenetic dysregulation, including altered DNA methylation, promotes PAH. Somatic mutations of Tet-methylcytosine-dioxygenase-2 (TET2), a key enzyme in DNA demethylation, occur in cardiovascular disease and are associated with clonal hematopoiesis, inflammation, and adverse vascular remodeling. The role of TET2 in PAH is unknown. METHODS To test for a role of TET2, we used a cohort of 2572 cases from the PAH Biobank. Within this cohort, gene-specific rare variant association tests were performed using 1832 unrelated European patients with PAH and 7509 non-Finnish European subjects from the Genome Aggregation Database (gnomAD) as control subjects. In an independent cohort of 140 patients, we quantified TET2 expression in peripheral blood mononuclear cells. To assess causality, we investigated hemodynamic and histological evidence of PAH in hematopoietic Tet2-knockout mice. RESULTS We observed an increased burden of rare, predicted deleterious germline variants in TET2 in PAH patients of European ancestry (9/1832) compared with control subjects (6/7509; relative risk=6; P=0.00067). Assessing the whole cohort, 0.39% of patients (10/2572) had 12 TET2 mutations (75% predicted germline and 25% somatic). These patients had no mutations in other PAH-related genes. Patients with TET2 mutations were older (71±7 years versus 48±19 years; P<0.0001), were more unresponsive to vasodilator challenge (0/7 versus 140/1055 [13.2%]), had lower pulmonary vascular resistance (5.2±3.1 versus 10.5±7.0 Wood units; P=0.02), and had increased inflammation (including elevation of interleukin-1β). Circulating TET2 expression did not correlate with age and was decreased in >86% of PAH patients. Tet2-knockout mice spontaneously developed PAH, adverse pulmonary vascular remodeling, and inflammation, with elevated levels of cytokines, including interleukin-1β. Long-term therapy with an antibody targeting interleukin-1β blockade resulted in regression of PAH. CONCLUSIONS PAH is the first human disease related to potential TET2 germline mutations. Inherited and acquired abnormalities of TET2 occur in 0.39% of PAH cases. Decreased TET2 expression is ubiquitous and has potential as a PAH biomarker.
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Balasubramanian A, Kolb TM, Damico RL, Hassoun PM, McCormack MC, Mathai SC. Diffusing Capacity Is an Independent Predictor of Outcomes in Pulmonary Hypertension Associated With COPD. Chest 2020; 158:722-734. [PMID: 32184109 DOI: 10.1016/j.chest.2020.02.047] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 01/02/2020] [Accepted: 02/09/2020] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Patients with COPD who experience pulmonary hypertension (PH) have worse mortality than those with COPD alone. Predictors of poor outcomes in COPD-PH are not well-described. Diffusing capacity of the lung (Dlco) assesses the integrity of the alveolar-capillary interface and thus may be a useful prognostic tool among those with COPD-PH. RESEARCH QUESTION Using a single center registry, we sought to evaluate Dlco as a predictor of mortality in a cohort of patients with COPD-PH. STUDY DESIGN AND METHODS This retrospective cohort study analyzed 71 COPD-PH patients from the Johns Hopkins Pulmonary Hypertension Registry with right-sided heart catheterization (RHC)-proven PH and pulmonary function testing data within one year of diagnostic RHC. Transplant-free survival was calculated from index RHC. Adjusted transplant-free survival was modelled using Cox proportional hazard methods; age, pulmonary vascular resistance, FEV1, oxygen use, and N-terminal pro-brain natriuretic peptide were included as covariates. RESULTS Overall unadjusted transplant-free 1-, 3-, and 5-year survivals were 87%, 60%, and 51%, respectively. Survival was associated with reduced Dlco across the observed range of pulmonary artery pressures and pulmonary vascular resistance. Severe Dlco impairment was associated with poorer survival (log-rank χ2 13.07) (P < .001); adjusting for covariates, for every percent predicted decrease in Dlco, mortality rates increased by 4% (hazard ratio, 1.04; 95% CI, 1.01-1.07). INTERPRETATION Among patients with COPD-PH, severe gas transfer impairment is associated with higher mortality, even with adjustment for airflow obstruction and hemodynamics, which suggests that Dlco may be a useful prognostic marker in this population. Future studies are needed to further investigate the association between Dlco and morbidity and to determine the utility of Dlco as a biomarker for disease risk and severity in COPD-PH.
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Simpson CE, Hassoun PM. Myocardial Fibrosis as a Potential Maladaptive Feature of Right Ventricle Remodeling in Pulmonary Hypertension. Am J Respir Crit Care Med 2020; 200:662-663. [PMID: 31216171 PMCID: PMC6775878 DOI: 10.1164/rccm.201906-1154ed] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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Tang WHW, Wilcox JD, Jacob MS, Rosenzweig EB, Borlaug BA, Frantz RP, Hassoun PM, Hemnes AR, Hill NS, Horn EM, Singh HS, Systrom DM, Tedford RJ, Vanderpool RR, Waxman AB, Xiao L, Leopold JA, Rischard FP. Comprehensive Diagnostic Evaluation of Cardiovascular Physiology in Patients With Pulmonary Vascular Disease: Insights From the PVDOMICS Program. Circ Heart Fail 2020; 13:e006363. [PMID: 32088984 DOI: 10.1161/circheartfailure.119.006363] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND Invasive hemodynamic evaluation through right heart catheterization plays an essential role in the diagnosis, categorization, and risk stratification of patients with pulmonary hypertension. METHODS Subjects enrolled in the PVDOMICS (Redefining Pulmonary Hypertension through Pulmonary Vascular Disease Phenomics) program undergo an extensive invasive hemodynamic evaluation that includes repeated measurements at rest and during several provocative physiological challenges. It is a National Institutes of Health/National Heart, Lung, and Blood Institute initiative to reclassify pulmonary hypertension groups based on clustered phenotypic and phenomic characteristics. At a subset of centers, participants also undergo an invasive cardiopulmonary exercise test to assess changes in hemodynamics and gas exchange during exercise. CONCLUSIONS When coupled with other physiological testing and blood -omic analyses involved in the PVDOMICS study, the comprehensive right heart catheterization protocol described here holds promise to clarify the diagnosis and clustering of pulmonary hypertension patients into cohorts beyond the traditional 5 World Symposium on Pulmonary Hypertension groups. This article will describe the methods applied for invasive hemodynamic characterization in the PVDOMICS program. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02980887.
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Samokhin AO, Hsu S, Yu PB, Waxman AB, Alba GA, Wertheim BM, Hopkins CD, Bowman F, Channick RN, Nikolic I, Faria-Urbina M, Hassoun PM, Leopold JA, Tedford RJ, Ventetuolo CE, Leary PJ, Maron BA. Circulating NEDD9 is increased in pulmonary arterial hypertension: A multicenter, retrospective analysis. J Heart Lung Transplant 2019; 39:289-299. [PMID: 31952977 DOI: 10.1016/j.healun.2019.12.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 11/11/2019] [Accepted: 12/26/2019] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Pulmonary arterial hypertension (PAH) is a highly morbid disease characterized by elevated pulmonary vascular resistance (PVR) and pathogenic right ventricular remodeling. Endothelial expression of the prometastatic protein NEDD9 is increased in fibrotic PAH arterioles, and NEDD9 inhibition decreases PVR in experimental PAH. We hypothesized that circulating NEDD9 is increased in PAH and informs the clinical profile of patients. METHODS Clinical data and plasma samples were analyzed retrospectively for 242 patients from 5 referral centers (2010-2017): PAH (n = 139; female 82%, 58 [48-67] years), non-PAH pulmonary hypertension (PH) (n = 54; female 56%, 63.4 ± 12.2 years), and dyspnea non-PH controls (n = 36; female 75%, 54.2 ± 14.0 years). RESULTS Compared with controls, NEDD9 was increased in PAH by 1.82-fold (p < 0.0001). Elevated NEDD9 correlated with PVR in idiopathic PAH (ρ = 0.42, p < 0.0001, n = 54), connective tissue disease (CTD)-PAH (ρ = 0.53, p < 0.0001, n = 53), and congenital heart disease-PAH (ρ = 0.68, p < 0.0001, n = 10). In CTD-PAH, NEDD9 correlated with 6-minute walk distance (ρ = -0.35, p = 0.028, n = 39). In contrast to the PAH biomarker N-terminal pro-brain natriuretic peptide (n = 38), NEDD9 correlated inversely with exercise pulmonary artery wedge pressure and more strongly with right ventricular ejection fraction (ρ = -0.41, p = 0.006, n = 45) in a mixed population. The adjusted hazard ratio for lung transplant-free survival was 1.12 (95% confidence interval [CI], 1.02-1.22, p = 0.01) and 1.75 (95% CI, 1.12-2.73, p = 0.01) per 1 ng/ml and 5 ng/ml increase in plasma NEDD9, respectively, by Cox proportional hazard model. CONCLUSIONS In PAH, plasma NEDD9 is increased and associates with key prognostic variables. Prospective studies that include hard end points are warranted to validate NEDD9 as a novel PAH biomarker.
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