Pulmonary hypertension in autoimmune rheumatic diseases

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

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).

Proteomic, biomechanical and functional analyses define neutrophil heterogeneity in systemic lupus erythematosus

OBJECTIVES

Low-density granulocytes (LDGs) are a distinct subset of proinflammatory and vasculopathic neutrophils expanded in systemic lupus erythematosus (SLE). Neutrophil trafficking and immune function are intimately linked to cellular biophysical properties. This study used proteomic, biomechanical and functional analyses to further define neutrophil heterogeneity in the context of SLE.

METHODS

Proteomic/phosphoproteomic analyses were performed in healthy control (HC) normal density neutrophils (NDNs), SLE NDNs and autologous SLE LDGs. The biophysical properties of these neutrophil subsets were analysed by real-time deformability cytometry and lattice light-sheet microscopy. A two-dimensional endothelial flow system and a three-dimensional microfluidic microvasculature mimetic (MMM) were used to decouple the contributions of cell surface mediators and biophysical properties to neutrophil trafficking, respectively.

RESULTS

Proteomic and phosphoproteomic differences were detected between HC and SLE neutrophils and between SLE NDNs and LDGs. Increased abundance of type 1 interferon-regulated proteins and differential phosphorylation of proteins associated with cytoskeletal organisation were identified in SLE LDGs relative to SLE NDNs. The cell surface of SLE LDGs was rougher than in SLE and HC NDNs, suggesting membrane perturbances. While SLE LDGs did not display increased binding to endothelial cells in the two-dimensional assay, they were increasingly retained/trapped in the narrow channels of the lung MMM.

CONCLUSIONS

Modulation of the neutrophil proteome and distinct changes in biophysical properties are observed alongside differences in neutrophil trafficking. SLE LDGs may be increasingly retained in microvasculature networks, which has important pathogenic implications in the context of lupus organ damage and small vessel vasculopathy.

Cardiogenic shock in autoimmune rheumatologic diseases: an insight on etiologies, management, and treatment outcomes

Autoimmune rheumatological disorders are known to have an increased risk for cardiovascular diseases including coronary artery disease (CAD), myocarditis, pericarditis, valvulopathy, and in consequence cardiogenic shock. Data on cardiogenic shock in rheumatological diseases are scarce; however, several reports have highlighted this specific entity. We sought to review the available literature and highlight major outcomes and the management approaches in each disease. Systematic literature search, including PubMed, Ovid/Medline, Cochrane Library, and Web of Science, was conducted between January 2000 and December 2009. We reviewed all cases reporting cardiogenic shock with rheumatologic conditions, including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), Takayasu's arteritis (TA), granulomatosis with polyangiitis (GPA), giant cell arteritis (GCA), and antiphospholipid syndrome (APS). We selected 45 papers reporting a total of 48 cases. Mean age was 39 ± 7.3 years and 68.8% were females. Most common rheumatologic conditions associated with cardiogenic shock were SLE (31%), GPA (23%), TA (14.6%), APA (10.4%), and RA (8.3%). Cardiogenic shock was found to be caused by eosinophilic myocarditis in 58% of cases, CAD in 19% of cases, and valvulopathy in 6% of cases. Most patient required high-dose steroids and second immunosuppressant therapy. Mechanical circulatory supported was required in 23 cases, IABP in 16 cases, and ECMO in 12 cases. Complete recovery occurred in 37 patients while 9 patients died and 2 required heart transplant. Responsible for two-thirds of cases, eosinophilic myocarditis should be suspected in young cardiogenic shock patients with underlying rheumatologic conditions. Lupus and GPA are the two most common conditions.

Challenges and opportunities in treating inflammation associated with pulmonary hypertension

INTRODUCTION

Inflammatory cells are present in the lungs from patients with many, if not all, forms of severe pulmonary hypertension.

AREAS COVERED

Historically the first inflammatory cell identified in the pulmonary vascular lesions was the mast cell. T and B lymphocytes, as well as macrophages, are present in and around the pulmonary arterioles and many patients have elevated blood levels of interleukin 1 and 6; some patients show elevated levels of leukotriene B4. An overlap between collagen-vascular disease-associated pulmonary arterial hypertension (PAH) and idiopathic PAH exists, yet only a few studies have been designed that evaluate the effect of anti-inflammatory treatments. Here we review the pertinent data that connect PAH and inflammation/autoimmune dysregulation and evaluate experimental models of severe PAH with an emphasis on the Sugen/athymic rat model of severe PAH. Expert commentary: We postulate that there are several inflammatory phenotypes and predict that there will be several anti-inflammatory treatment strategies for severe PAH.

Pulmonary hypertension in systemic lupus erythematosus: pulmonary thromboembolism is the leading cause

BACKGROUND

Pulmonary hypertension (PH) is a life-threatening complication of systemic lupus erythematosus (SLE). Pulmonary hypertension in SLE has a variety of causes. Diagnosing early and defining the cause of PH accurately can provide better clinical outcome in SLE. We investigated the causes and characteristics of PH in patients with SLE.

METHODS

One hundred twenty-one patients with SLE who had a visit in a 6-month period were assessed retrospectively. Patients who ever had a systolic pulmonary arterial pressure of 40 mm Hg or greater by Doppler echocardiography were considered to have PH.

RESULTS

Among 122 patients, 65 had echocardiography for some reason, and 10 (8.2%) were diagnosed as having PH by echocardiographic examination. This number reduced to 9 (7.4%) when we excluded the patient with normal pulmonary artery pressure at right heart catheterization. Causes of PH were as follows: thromboembolic events in 4 patients (44.4%) (2 of them had chronic thromboembolic PH), left-sided heart disease in 2 patients (22.2%), pulmonary arterial hypertension in 1 patient (11.1%), high cardiac output state in 1 patient (11.1%), and transient elevation of systolic pulmonary artery pressure in 1 patient (11.1%) who had a history of venous thromboembolism. Venous thromboembolic disease was significantly higher in patients with SLE with PH in comparison to patients with SLE without PH (7 patients [6.3%] vs 5 patients [50.0%]; P = 0.001). All patients improved clinically during their short-term follow-up.

CONCLUSIONS

Patients with SLE are at increased risk for PH. This study highlights the complexity of the differential diagnosis of PH in patients with SLE once again and emphasizes the importance of pulmonary thromboembolism as a cause of PH. One should investigate patients with SLE with unexplained symptoms and/or signs related to PH for possible treatable causes.

Cardiac manifestations in systemic sclerosis

Primary cardiac involvement, which develops as a direct consequence of systemic sclerosis (SSc), may manifest as myocardial damage, fibrosis of the conduction system, pericardial and, less frequently, as valvular disease. In addition, cardiac complications in SSc may develop as a secondary phenomenon due to pulmonary arterial hypertension and kidney pathology. The prevalence of primary cardiac involvement in SSc is variable and difficult to determine because of the diversity of cardiac manifestations, the presence of subclinical periods, the type of diagnostic tools applied, and the diversity of patient populations. When clinically manifested, cardiac involvement is thought to be an important prognostic factor. Profound microvascular disease is a pathognomonic feature of SSc, as both vasospasm and structural alterations are present. Such alterations are thought to predict macrovascular atherosclerosis over time. There are contradictory reports regarding the prevalence of atherosclerosis in SSc. According to some authors, the prevalence of atherosclerosis of the large epicardial coronary arteries is similar to that of the general population, in contrast with other rheumatic diseases such as rheumatoid arthritis and systemic lupus erythematosus. However, the level of inflammation in SSc is inferior. Thus, the atherosclerotic process may not be as aggressive and not easily detectable in smaller studies. Echocardiography (especially tissue Doppler imaging), single-photon emission computed tomography, magnetic resonance imaging and cardiac computed tomography are sensitive techniques for earlier detection of both structural and functional scleroderma-related cardiac pathologies. Screening for subclinical cardiac involvement via modern, sensitive tools provides an opportunity for early diagnosis and treatment, which is of crucial importance for a positive outcome.

Increased vascular density is a persistent feature of airway remodeling in a sheep model of chronic asthma

BACKGROUND

Increases in blood vessel density and vascular area are now recognized as important features of remodeled airways in asthma. However, the time sequence for these vascular changes and whether they resolve in the absence of continued antigenic exposure is not well elucidated. The aim of the present study was to correlate progressive changes in airway vascularity with changes in functional airway responses in sheep chronically challenged with house dust mite (HDM) allergen, and to examine the resolution of vascular remodeling following allergen withdrawal.

METHODS

Progressive changes in vascular indices were examined in four spatially separate lung segments that received weekly challenges with HDM allergen for 0, 8, 16, or 24 weeks. Reversibility of these changes was assessed in a separate experiment in which two lung segments received 24 weeks of HDM challenges and either no rest or 12 weeks rest. Lung tissue was collected from each segment 7 days following the final challenge and vascular changes assessed by a morphometric analysis of airways immunohistochemically stained with an antibody against type IV collagen.

RESULTS

Blood vessel density and percent airway vascularity were significantly increased in bronchi following 24 weeks of HDM challenges compared to untreated controls (P < .05), but not at any of the other time-points. There was no significant correlation between vascular indices and airway responses to allergic or nonspecific stimuli. The increase in blood vessel density induced by repeated allergen exposures did not return to baseline levels following a 12-week withdrawal period from allergen.

CONCLUSIONS

Our results show for the first time that the airways of sheep chronically exposed to HDM allergen undergo vascular remodeling. These findings show the potential of this large animal model for investigating airway angiogenesis in asthma.

Plexiform lesions in pulmonary arterial hypertension composition, architecture, and microenvironment

Pulmonary arterial hypertension (PAH) is a debilitating disease with a high mortality rate. A hallmark of PAH is plexiform lesions (PLs), complex vascular formations originating from remodeled pulmonary arteries. The development and significance of these lesions have been debated and are not yet fully understood. Some features of PLs resemble neoplastic disorders, and there is a striking resemblance to glomeruloid-like lesions (GLLs) in glioblastomas. To further elucidate PLs, we used in situ methods, such as (fluorescent) IHC staining, three-dimensional reconstruction, and laser microdissection, followed by mRNA expression analysis. We generated compartment-specific expression patterns in the lungs of 25 patients (11 with PAH associated with systemic shunts, 6 with idiopathic PAH, and 8 controls) and GLLs from 5 glioblastomas. PLs consisted of vascular channels lined by a continuously proliferating endothelium and backed by a uniform myogenic interstitium. They also showed up-regulation of remodeling-associated genes, such as HIF1a, TGF-β1, VEGF-α, VEGFR-1/-2, Ang-1, Tie-2, and THBS1, but also of cKIT and sprouting-associated markers, such as NOTCH and matrix metalloproteinases. The cellular composition and signaling seen in GLLs in neural neoplasms differed significantly from those in PLs. In conclusion, PLs show a distinct cellular composition and microenvironment, which contribute to the plexiform phenotype and set them apart from other processes of vascular remodeling in patients with PAH. Neoplastic models of angiogenesis seem to be of limited use in further study of plexiform vasculopathy.

Pulmonary arterial hypertension in systemic sclerosis

Pulmonary arterial hypertension (PAH) in systemic sclerosis (SSc) is a complex clinical situation resulting from restricted flow through the pulmonary arterial circulation ending in increased pulmonary vascular resistance and right heart failure. PAH is a common and life-threatening complication in connective tissue diseases, specifically in SSc if not treated rapidly and adequately. Based on the emerging knowledge in SSc epidemiology by large scale patient cohorts such as EUSTAR, of PAH pathophysiology and advances in cardiopulmonary diagnostic techniques, several novel treatment approaches have been examined and have proceeded to licensing and daily use in the clinical practice. Amongst them are different endothelin receptor antagonists and PDE-5 inhibitors, but several other ideas are being currently pursued to improve the long-term outcome of the affected patients.

Advances in the understanding and classification of pulmonary hypertension

Pulmonary hypertension has a complex pathobiology and the term pulmonary arterial hypertension (PAH) includes a variety of pulmonary hypertensive diseases that have different aetiologies, but which may have a similar clinical presentation and, in some cases, the same response to medical treatment. More recent classifications have been based on aetiology, functional data and clinical presentation, but morphometric studies have shown differences in the distribution and prevalence of vascular changes amongst cases of PAH of different aetiologies. Recent advances in the understanding of some aspects of the genetic and molecular mechanisms, together with detailed descriptions of the histopathological findings in PAH cases of different aetiologies, should contribute to a better understanding of the relationships of the various subsets of the disease, the prognostic implications and possible treatment options.

Resistin-like molecule-beta in scleroderma-associated pulmonary hypertension

Scleroderma is a systemic, mixed connective tissue disease that can impact the lungs through pulmonary fibrosis, vascular remodeling, and the development of pulmonary hypertension and right heart failure. Currently, little is known about the molecular mechanisms that drive this condition, but we have recently identified a novel gene product that is up-regulated in a murine model of hypoxia-induced pulmonary hypertension. This molecule, known as hypoxia-induced mitogenic factor (HIMF), is a member of the newly described resistin gene family. We have demonstrated that HIMF has mitogenic, angiogenic, vasoconstrictive, inflammatory, and chemokine-like properties, all of which are associated with vascular remodeling in the lung. Here, we demonstrate that the human homolog of HIMF, resistin-like molecule (RELM)-beta, is expressed in the lung tissue of patients with scleroderma-associated pulmonary hypertension and is up-regulated compared with normal control subjects. Immunofluorescence colocalization revealed that RELM-beta is expressed in the endothelium and vascular smooth muscle of remodeled vessels, as well as in plexiform lesions, macrophages, T cells, and myofibroblast-like cells. We also show that addition of recombinant RELM-beta induces proliferation and activation of ERK1/2 in primary cultured human pulmonary endothelial and smooth muscle cells. These results suggest that RELM-beta may be involved in the development of scleroderma-associated pulmonary hypertension.

Pulmonary complications of connective tissue diseases

Lung involvement is common in patients who have complications of connective tissue disease (CTDs) and causes considerable morbidity and mortality. High resolution CT (HRCT) has a pivotal role in the detection of lung fibrosis. In patients who have coexistent pathologic processes, HRCT often allows the predominant process to be identified. HRCT has an important role in detecting possible complications such as opportunistic infection or the development of malignancy. However, the limitations of HRCT should not be overlooked. In many cases, HRCT appearances are nonspecific and may or may not be related to an underlying CTD. Thus, radiologic findings should never be interpreted without knowledge of the clinical picture.

Identification of candidate genes in scleroderma-related pulmonary arterial hypertension

We hypothesize that pulmonary arterial hypertension (PAH)-associated genes identified by expression profiling of peripheral blood mononuclear cells (PBMCs) from patients with idiopathic pulmonary arterial hypertension (IPAH) can also be identified in PBMCs from scleroderma patients with PAH (PAH-SSc). Gene expression profiles of PBMCs collected from IPAH (n = 9), PAH-SSc (n = 10) patients, and healthy controls (n = 5) were generated using HG_U133A_2.0 GeneChips and were processed by the RMA/GCOS_1.4/SAM_1.21 data analysis pipeline. Disease severity in consecutive patients was assessed by functional status and hemodynamic measurements. The expression profiles were analyzed using PAH severity-stratification, and identified candidate genes were validated with real-time polymerase chain reaction (PCR). Transcriptomics of PBMCs from IPAH patients was highly comparable with that of PMBCs from PAH-SSc patients. The PBMC gene expression patterns significantly correlate with right atrium pressure (RA) and cardiac index (CI), which are known predictors of survival in PAH. Array stratification by RA and CI identified 364 PAH-associated candidate genes. Gene ontology (GO) analysis revealed significant (Z(score) > 1.96) alterations in angiogenesis genes according to PAH severity: matrix metalloproteinase 9 (MMP9) and vascular endothelial growth factor (VEGF) were significantly upregulated in mild as compared with severe PAH and healthy controls, as confirmed by real-time PCR. These data demonstrate that PBMCs from patients with PAH-SSc carry distinct transcriptional expression. Furthermore, our findings suggest an association between angiogenesis-related gene expression and severity of PAH in PAH-SSc patients. Deciphering the role of genes involved in vascular remodeling and PAH development may reveal new treatment targets for this devastating disorder.

Increased regulatory and decreased CD8+ cytotoxic T cells in the blood of patients with idiopathic pulmonary arterial hypertension

BACKGROUND

An association between pulmonary arterial hypertension (PAH) and various immune disorders is well established. Recently, the role of an intact immune system in protecting against pulmonary angioproliferation was shown in an animal model.

OBJECTIVE

To elucidate the role of T cells in human PAH, we comparatively studied T cell subclasses with emphasis on regulatory T cells (T(reg)) in the peripheral blood of patients with idiopathic pulmonary arterial hypertension (IPAH) and healthy controls.

METHODS

Isolated peripheral blood mononuclear cells from 36 patients diagnosed with IPAH and 33 healthy controls were stained with fluorescently labeled monoclonal antibodies against superficial T cell markers (CD3, CD4, CD8, CD25) and FoxP3, the intracellular marker of T(reg) cells. The relative cell distribution was analyzed by flow cytometry. The functionality of patient and control T(reg) cells was assessed by coculture of T(reg) with nonregulatory T cells from the same individual.

RESULTS

Significantly less CD8+ T cells (p = 0.02) and more CD25hi+ and FoxP3+CD4+ T cells were found in the peripheral blood of patients compared with controls (p = 0.009 and p < 0.001, respectively). The percentage of FoxP3+ cells within the CD25hi+CD4+ T(reg) cells was similar. T(reg) cell functionality was equal in patients and controls.

CONCLUSION

Our findings of decreased CD8+ T cells and increased T(reg) cells in the peripheral blood of patients with IPAH are novel and may have implications for directing future research in the field to elucidate the differential role of T cells and the immune system in IPAH.

Scleroderma Lung

The lungs are frequently involved in systemic sclerosis ('scleroderma'), a rare, disabling disease of unknown origin, characterised by skin thickening and Raynaud's phenomenon. The pathogenesis of scleroderma is complex, but signs and symptoms of excessive fibrosis, vasculopathy and inflammation are almost universally present. Dyspnoea in scleroderma patients can be due to chest wall tightening from skin thickening, pleural disease, cardiac involvement, myositis of intercostal muscles, or so-called scleroderma lung disease. Scleroderma lung disease encompasses vascular (pulmonary artery hypertension) or interstitial lung disease, or both. A comprehensive work-up is required to delineate the underlying cause of dyspnoea in a scleroderma patient, and to establish the contribution of each component to the symptoms. This should include a 6-minute walk test, pulmonary function testing, high-resolution thoracic CT scanning, ECG, echocardiography and, if pulmonary artery hypertension is suspected, right-heart catheterisation; bronchoalveolar lavage is optional. Lung disease in scleroderma contributes significantly to excess morbidity and early mortality, especially when diffusion capacity drops below 40% and/or forced vital capacity below 50%. However, recent clinical studies have unequivocally demonstrated that scleroderma lung disease is amenable to treatment with new vasodilatory drugs that target specific pathways involved in vasoconstriction, or with cyclophosphamide for interstitial lung disease. Uncontrolled studies have suggested that these therapies also have an impact on survival, but controlled studies with a long follow-up are needed to corroborate this point.