Blood CD9+ B cell, a biomarker of bronchiolitis obliterans syndrome after lung transplantation

Bronchiolitis obliterans syndrome is the main limitation for long-term survival after lung transplantation. Some specific B cell populations are associated with long-term graft acceptance. We aimed to monitor the B cell profile during early development of bronchiolitis obliterans syndrome after lung transplantation. The B cell longitudinal profile was analyzed in peripheral blood mononuclear cells from patients with bronchiolitis obliterans syndrome and patients who remained stable over 3 years of follow-up. CD24^hi CD38^hi transitional B cells were increased in stable patients only, and reached a peak 24 months after transplantation, whereas they remained unchanged in patients who developed a bronchiolitis obliterans syndrome. These CD24^hi CD38^hi transitional B cells specifically secrete IL-10 and express CD9. Thus, patients with a total CD9⁺ B cell frequency below 6.6% displayed significantly higher incidence of bronchiolitis obliterans syndrome (AUC = 0.836, PPV = 0.75, NPV = 1). These data are the first to associate IL-10-secreting CD24^hi CD38^hi transitional B cells expressing CD9 with better allograft outcome in lung transplant recipients. CD9-expressing B cells appear as a contributor to a favorable environment essential for the maintenance of long-term stable graft function and as a new predictive biomarker of bronchiolitis obliterans syndrome-free survival.

Assessment of Right Ventricular Function in the Research Setting: Knowledge Gaps and Pathways Forward. An Official American Thoracic Society Research Statement

BACKGROUND

Right ventricular (RV) adaptation to acute and chronic pulmonary hypertensive syndromes is a significant determinant of short- and long-term outcomes. Although remarkable progress has been made in the understanding of RV function and failure since the meeting of the NIH Working Group on Cellular and Molecular Mechanisms of Right Heart Failure in 2005, significant gaps remain at many levels in the understanding of cellular and molecular mechanisms of RV responses to pressure and volume overload, in the validation of diagnostic modalities, and in the development of evidence-based therapies.

METHODS

A multidisciplinary working group of 20 international experts from the American Thoracic Society Assemblies on Pulmonary Circulation and Critical Care, as well as external content experts, reviewed the literature, identified important knowledge gaps, and provided recommendations.

RESULTS

This document reviews the knowledge in the field of RV failure, identifies and prioritizes the most pertinent research gaps, and provides a prioritized pathway for addressing these preclinical and clinical questions. The group identified knowledge gaps and research opportunities in three major topic areas: 1) optimizing the methodology to assess RV function in acute and chronic conditions in preclinical models, human studies, and clinical trials; 2) analyzing advanced RV hemodynamic parameters at rest and in response to exercise; and 3) deciphering the underlying molecular and pathogenic mechanisms of RV function and failure in diverse pulmonary hypertension syndromes.

CONCLUSIONS

This statement provides a roadmap to further advance the state of knowledge, with the ultimate goal of developing RV-targeted therapies for patients with RV failure of any etiology.

Characterization of Kcnk3-Mutated Rat, a Novel Model of Pulmonary Hypertension

RATIONALE

Pulmonary arterial hypertension is a severe lethal cardiopulmonary disease. Loss of function mutations in KCNK3 (potassium channel subfamily K member 3) gene, which encodes an outward rectifier K⁺ channel, have been identified in pulmonary arterial hypertension patients.

OBJECTIVE

We have demonstrated that KCNK3 dysfunction is common to heritable and nonheritable pulmonary arterial hypertension and to experimental pulmonary hypertension (PH). Finally, KCNK3 is not functional in mouse pulmonary vasculature.

METHODS AND RESULTS

Using CRISPR/Cas9 technology, we generated a 94 bp out of frame deletion in exon 1 of Kcnk3 gene and characterized these rats at the electrophysiological, echocardiographic, hemodynamic, morphological, cellular, and molecular levels to decipher the cellular mechanisms associated with loss of KCNK3. Using patch-clamp technique, we validated our transgenic strategy by demonstrating the absence of KCNK3 current in freshly isolated pulmonary arterial smooth muscle cells from Kcnk3-mutated rats. At 4 months of age, echocardiographic parameters revealed shortening of the pulmonary artery acceleration time associated with elevation of the right ventricular systolic pressure. Kcnk3-mutated rats developed more severe PH than wild-type rats after monocrotaline exposure or chronic hypoxia exposure. Kcnk3-mutation induced a lung distal neomuscularization and perivascular extracellular matrix activation. Lungs of Kcnk3-mutated rats were characterized by overactivation of ERK1/2 (extracellular signal-regulated kinase1-/2), AKT (protein kinase B), SRC, and overexpression of HIF1-α (hypoxia-inducible factor-1 α), survivin, and VWF (Von Willebrand factor). Linked with plasma membrane depolarization, reduced endothelial-NOS expression and desensitization of endothelial-derived hyperpolarizing factor, Kcnk3-mutated rats presented predisposition to vasoconstriction of pulmonary arteries and a severe loss of sildenafil-induced pulmonary arteries relaxation. Moreover, we showed strong alteration of right ventricular cardiomyocyte excitability. Finally, Kcnk3-mutated rats developed age-dependent PH associated with low serum-albumin concentration.

CONCLUSIONS

We established the first Kcnk3-mutated rat model of PH. Our results confirm that KCNK3 loss of function is a key event in pulmonary arterial hypertension pathogenesis. This model presents new opportunities for understanding the initiating mechanisms of PH and testing biologically relevant therapeutic molecules in the context of PH.

Smooth Muscle Phenotype in Idiopathic Pulmonary Hypertension: Hyper-Proliferative but not Cancerous

Idiopathic pulmonary arterial hypertension (IPAH) is a complex disease associated with vascular remodeling and a proliferative disorder in pulmonary artery smooth muscle cells (PASMCs) that has been variably described as having neoplastic features. To decode the phenotype of PASMCs in IPAH, PASMCs from explanted lungs of patients with IPAH (IPAH-PASMCs) and from controls (C-PASMCs) were cultured. The IPAH-PASMCs grew faster than the controls; however, both growth curves plateaued, suggesting contact inhibition in IPAH cells. No proliferation was seen without stimulation with exogenous growth factors, suggesting that IPAH cells are incapable of self-sufficient growth. IPAH-PASMCs were more resistant to apoptosis than C-PASMCs, consistent with the increase in the Bcl2/Bax ratio. As cell replication is governed by telomere length, these parameters were assessed jointly. Compared to C-PASMCs, IPAH-PASMCs had longer telomeres, but a limited replicative capacity. Additionally, it was noted that IPAH-PASMCs had a shift in energy production from mitochondrial oxidative phosphorylation to aerobic glycolysis. As DNA damage and genomic instability are strongly implicated in IPAH development a comparative genomic hybridization was performed on genomic DNA from PASMCs which showed multiple break-points unaffected by IPAH severity. Activation of DNA damage/repair factors (γH2AX, p53, and GADD45) in response to cisplatin was measured. All proteins showed lower phosphorylation in IPAH samples than in controls, suggesting that the cells were resistant to DNA damage. Despite the cancer-like processes that are associated with end-stage IPAH-PASMCs, we identified no evidence of self-sufficient proliferation in these cells—the defining feature of neoplasia.

ICAM-1 promotes the abnormal endothelial cell phenotype in chronic thromboembolic pulmonary hypertension

BACKGROUND

Pulmonary endothelial cells play a key role in the pathogenesis of Chronic Thromboembolic Pulmonary Hypertension (CTEPH). Increased synthesis and/or the release of intercellular adhesion molecule-1 (ICAM-1) by pulmonary endothelial cells of patients with CTEPH has been recently reported, suggesting a potential role for ICAM-1 in CTEPH.

METHODS

We studied pulmonary endarterectomy specimens from 172 patients with CTEPH and pulmonary artery specimens from 97 controls undergoing lobectomy for low-stage cancer without metastasis.

RESULTS

ICAM-1 was overexpressed in vitro in isolated and cultured endothelial cells from endarterectomy specimens. Endothelial cell growth and apoptosis resistance were significantly higher in CTEPH specimens than in the controls (p < 0.001). Both abnormalities were abolished by pharmacological inhibition of ICAM-1 synthesis or activity. The overexpression of ICAM-1 contributed to the acquisition and maintenance of abnormal EC growth and apoptosis resistance via the phosphorylation of SRC, p38 and ERK1/2 and the overproduction of survivin. Regarding the ICAM-1 E469K polymorphism, the KE heterozygote genotype was significantly more frequent in CTEPH than in the controls, but it was not associated with disease severity among patients with CTEPH.

CONCLUSIONS

ICAM-1 contributes to maintaining the abnormal endothelial cell phenotype in CTEPH.

Central versus peripheral cannulation of extracorporeal membrane oxygenation support during double lung transplant for pulmonary hypertension

OBJECTIVES

Extracorporeal membrane oxygenation (ECMO) has become the standard of cardiopulmonary support during a sequential double lung transplant for pulmonary hypertension. Whether central or peripheral cannulation is the best strategy for these patients remains unknown. Our goal was to determine which is the best strategy by comparing 2 populations of patients.

METHODS

We performed a single-centre retrospective study based on an institutional prospective lung transplant database.

RESULTS

Between January 2011 and November 2016, 103 patients underwent double lung transplant for pulmonary hypertension. We compared 54 patients who had central ECMO (cECMO group) to 49 patients who had peripheral ECMO (pECMO group). The pECMO group had significantly more bridged patients who received emergency transplants (31% vs 6%, P = 0.001). The incidence of Grade 3 primary graft dysfunction requiring ECMO (14% vs 11%, P = not significant) and of in-hospital mortality (11% vs 14%, P = not significant) was similar between the groups. Groin infections (16% vs 4%, P = 0.031), deep vein thrombosis (27% vs 11%, P = 0.044) and lower limb ischaemia (12% vs 2%, P = 0.031) occurred significantly more often in the pECMO group. The number of chest reopenings for bleeding or infection was similar between the groups. The 3-month, 1-year and 5-year survival rates did not differ between the groups (P = 0.94).

CONCLUSIONS

Central or peripheral ECMO produced similar results during double lung transplant for pulmonary hypertension in terms of in-hospital deaths and long-term survival rates. Central ECMO provided satisfactory results without major bleeding provided the patient was weaned from ECMO at the end of the procedure. Despite the rate of groin and lower limb complications, peripheral cannulation remained the preferred solution to bridge the patient to transplant or for postoperative support.

French experience of balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension

AIMS

To evaluate safety and efficacy of balloon pulmonary angioplasty (BPA) in a large cohort of patients with chronic thromboembolic pulmonary hypertension (CTEPH).

METHODS

From 2014 to 2017, 184 inoperable CTEPH patients underwent 1006 BPA sessions. Safety and efficacy during the first 21 months (initial period) were compared with those of the last 21 months (recent period). A total of 154 patients had a full evaluation after a median duration of 6.1 months.

RESULTS

Overall, there was a significant improvement in New York Heart Association functional class, 6-min walk distance (mean change +45 m), and a significant decrease in mean pulmonary artery pressure (PAP) and in pulmonary vascular resistance (PVR) by 26% and 43%, respectively. The percentage decreases of mean PAP and PVR were 22% and 37% in the initial period versus 30% and 49% in the recent period, respectively (p<0.05). The main complications included lung injury, which occurred in 9.1% of 1006 sessions (13.3% in the initial period versus 5.9% in the recent period; p<0.001). Per-patient multivariate analysis revealed that baseline mean PAP and the period during which BPA procedure was performed (recent versus initial period) were the strongest factors related to the occurrence of lung injury. 3-year survival was 95.1%.

CONCLUSION

This study confirms that a refined BPA strategy improves short-term symptoms, exercise capacity and haemodynamics in inoperable CTEPH patients with an acceptable risk-benefit ratio. Safety and efficacy improve over time, underscoring the unavoidable learning curve for this procedure.

Right ventricular mitochondrial respiratory function in a piglet model of chronic pulmonary hypertension

OBJECTIVE

We aimed to assess the mitochondrial respiratory capacities in the right ventricle in the setting of ventricular remodeling induced by pressure overload.

METHODS

Chronic thromboembolic pulmonary hypertension was induced in 8 piglets over a 12-week period (chronic thromboembolic pulmonary hypertension model). Right ventricular remodeling, right ventricular function, and mitochondrial respiratory function were assessed at 3, 6, and 12 weeks after induction of pulmonary hypertension and were compared with sham animals (n = 5). Right ventricular cardiomyocytes and mitochondrial structure were studied in transmission electronic microscopy after 12 weeks.

RESULTS

As of 3 weeks, chronic pressure overload induced right ventricular dilatation, right ventricular hypertrophy, and right ventricular dysfunction. Maladaptive remodeling in the chronic thromboembolic pulmonary hypertension model was confirmed by the decrease of right ventricular pulmonary artery coupling and right fractional area change. Mitochondrial functional assays in permeabilized right ventricular myocardial fibers revealed that oxidative phosphorylation capacities (complex I, complex II, and IV of the mitochondrial respiratory chain) were degraded. Furthermore, no change in substrate preference of mitochondria was found in the overloaded right ventricle. There was a good correlation between maximal mitochondrial oxygen consumption rate and right ventricular pulmonary artery coupling (Pearson coefficient r = 0.83). Transmission electronic microscopy analysis showed that the composition of cardiomyocytes was no different between the chronic thromboembolic pulmonary hypertension group and the sham group. However, mitochondrial structure anomalies were significantly increased in the chronic thromboembolic pulmonary hypertension group.

CONCLUSIONS

Mitochondrial respiratory function impairment is involved early in the development of right ventricular dysfunction in a piglet model of chronic thromboembolic pulmonary hypertension. Underlying mechanisms remain to be elucidated.

Hybrid treatment of a giant thoracic aneurysm in a 38 year-old woman

A 38-year-old woman, with no comorbidities, presented to an outside institution with a 10-cm aortic arch and descending thoracic aortic aneurysm. After an aborted attempt at hybrid repair, she underwent successful, staged repair with zone 1 thoracic endovascular aortic repair and open aneurysmal sac revision. The patient made an uneventful recovery with computed tomographic evidence of complete aneurysmal exclusion. This case demonstrates many of the techniques and issues in the evolving field of aortic arch repair.

Deep learning using tumor HLA peptide mass spectrometry datasets improves neoantigen identification

Neoantigens, which are expressed on tumor cells, are one of the main targets of an effective antitumor T-cell response. Cancer immunotherapies to target neoantigens are of growing interest and are in early human trials, but methods to identify neoantigens either require invasive or difficult-to-obtain clinical specimens, require the screening of hundreds to thousands of synthetic peptides or tandem minigenes, or are only relevant to specific human leukocyte antigen (HLA) alleles. We apply deep learning to a large (N = 74 patients) HLA peptide and genomic dataset from various human tumors to create a computational model of antigen presentation for neoantigen prediction. We show that our model, named EDGE, increases the positive predictive value of HLA antigen prediction by up to ninefold. We apply EDGE to enable identification of neoantigens and neoantigen-reactive T cells using routine clinical specimens and small numbers of synthetic peptides for most common HLA alleles. EDGE could enable an improved ability to develop neoantigen-targeted immunotherapies for cancer patients.

Forgotten No More: A Focused Update on the Right Ventricle in Cardiovascular Disease

In the last decade, there has been renewed interest in the study of the right ventricle. It is now well established that right ventricular function is a strong predictor of mortality, not only in heart failure but also in pulmonary hypertension, congenital heart disease, and cardiothoracic surgery. The right ventricle is part of a cardiopulmonary unit with connections to the pulmonary circulation, venous return, atria, and left ventricle. In this context, ventriculoarterial coupling, interventricular interactions, and pericardial constraint become important to understand right ventricular adaptation to injury or abnormal loading conditions. This state-of-the-art review summarizes major advances that occurred in the field of right ventricular research over the last decade. The first section focuses on right ventricular physiology and pulmonary circulation. The second section discusses the emerging data on right ventricular phenotyping, highlighting the importance of myocardial deformation (strain) imaging and assessment of end-systolic dimensions. The third section reviews recent clinical trials involving patients at risk for or with established right ventricular failure, focusing on beta blockade, phosphodiesterase inhibition, and mechanical support of the failing right heart. The final section presents a perspective on active areas of research that are most likely to translate in clinical practice in the next decade.

Autologous endothelial progenitor cell therapy improves right ventricular function in a model of chronic thromboembolic pulmonary hypertension

BACKGROUND

Right ventricular (RV) failure is the main prognostic factor in pulmonary hypertension, and ventricular capillary density (CD) has been reported to be a marker of RV maladaptive remodeling and failure. Our aim was to determine whether right intracoronary endothelial progenitor cell (EPC) infusion can improve RV function and CD in a piglet model of chronic thromboembolic pulmonary hypertension (CTEPH).

METHODS

We compared 3 groups: sham (n = 5), CTEPH (n = 6), and CTEPH with EPC infusion (CTEPH+EPC; n = 5). After EPC isolation from CTEPH+EPC piglet peripheral blood samples at 3 weeks, the CTEPH and sham groups underwent right intracoronary infusion of saline, and the CTEPH+EPC group received EPCs at 6 weeks. RV function, pulmonary hemodynamics, and myocardial morphometry were investigated in the animals at 10 weeks.

RESULTS

After EPC administration, the RV fractional area change increased from 32.75% (interquartile range [IQR], 29.5%-36.5%) to 39% (IQR, 37.25%-46.50%; P = .030). The CTEPH+EPC piglets had reduced cardiomyocyte surface areas (from 298.3 μm² [IQR, 277.4-335.3 μm²] to 234.6 μm² (IQR, 211.1-264.7 μm²; P = .017), and increased CD31 expression (from 3.12 [IQR, 1.27-5.09] to 7.14 [IQR, 5.56-8.41; P = .017). EPCs were found in the RV free wall at 4 and 24 hours after injection but not 4 weeks later.

CONCLUSIONS

Intracoronary infusion of EPC improved RV function and CD in a piglet model of CTEPH. This novel cell-based therapy might represent a promising RV-targeted treatment in patients with pulmonary hypertension.

Endobronchial ultrasound-guided fine-needle aspiration for pulmonary carcinomas genotyping: experience with 398 cases including rapid EGFR/KRAS analysis in 43 cases

BACKGROUND

Endobronchial ultrasound-guided fine-needle aspiration (EBUS-FNA) of mediastinal lymph nodes is a minimally invasive and efficient tool for both diagnosis and staging of lung cancer. EBUS-FNA also permits tumor genotyping. However this critical datum for the therapeutic management is often long to obtain for metastatic patients with short life expectancy.

METHODS

From May 2011 to December 2017, 398 lung cancer patients underwent a genetic analysis based on EBUS-FNA samples. EBUS-FNAs were performed with rapid on-site evaluation. Mutations were studied with Sanger or new generation sequencing. Forty-three cases were also tested with a fully automated real-time PCR rapid technique. ALK abnormalities were assessed by immunohistochemistry and/or in situ hybridization.

RESULTS

A genotypic result could be obtained in 316 cases (79.4%) and in 180 of the 198 more recent cases (90.9%). Genetic abnormalities were observed in 191 cases (48.0%). Using the rapid technique, EGFR/KRAS mutational status was obtained within a few hours following the histological diagnosis and on the same day of the EBUS-FNA by analyzing fresh specimens after intra-operative cytological diagnosis.

CONCLUSIONS

In term of molecular diagnosis, EBUS-FNA provides high-quality biological material similar to that of other clinical sampling methods. Furthermore, our study suggests that a rapid molecular diagnostic method could lead to a prompt and appropriate therapeutic management for many advanced stage patients.