Connective tissue disease-associated pulmonary arterial hypertension

The Role of Anti-U1 RNP Antibody in Connective Tissue Disease-Associated Pulmonary Arterial Hypertension: A Systematic Review and Meta-Analysis

Connective tissue disease (CTD) patients may suffer from pulmonary arterial hypertension (PAH), a serious complication, and anti-U1 ribonucleoprotein (RNP) antibodies can be used as a potential indicator for the development and prognosis of CTD-associated PAH (CTD-PAH). However, there are still some controversies; thus, a systematic review and meta-analysis were performed. We searched PubMed, Embase, Cochrane Library, and Scopus for eligible studies and assessed their quality using Newcastle−Ottawa scales or Agency for Healthcare Research and Quality indicators according to the type of research. Odds ratio (OR) was adopted as a measure of effect in risk factor analysis, and hazard ratio (HR) was adopted for prognostic factor analysis. Publication bias was evaluated using the Egger’s test. Thirteen studies were finally included. Anti-U1 RNP antibody was proved as a risk factor for PAH among CTD patients (OR = 5.30, 95%CI 2.96−9.48, p < 0.05) and a protective factor against mortality among CTD-PAH patients (HR = 0.55, 95%CI 0.36−0.83, p < 0.05). CTD patients with positive anti-U1 RNP antibodies are at high risk for PAH, so routine screening examinations, including echocardiography, are recommended. Additionally, anti-U1 RNP positivity has been linked to decreased mortality in patients with CTD-PAH.

Text Mining-Based Drug Discovery for Connective Tissue Disease–Associated Pulmonary Arterial Hypertension

Background: The current medical treatments for connective tissue disease–associated pulmonary arterial hypertension (CTD-PAH) do not show favorable efficiency for all patients, and identification of novel drugs is desired.

Methods: Text mining was performed to obtain CTD- and PAH-related gene sets, and the intersection of the two gene sets was analyzed for functional enrichment through DAVID. The protein–protein interaction network of the overlapping genes and the significant gene modules were determined using STRING. The enriched candidate genes were further analyzed by Drug Gene Interaction database to identify drugs with potential therapeutic effects on CTD-PAH.

Results: Based on text mining analysis, 179 genes related to CTD and PAH were identified. Through enrichment analysis of the genes, 20 genes representing six pathways were obtained. To further narrow the scope of potential existing drugs, we selected targeted drugs with a Query Score ≥5 and Interaction Score ≥1. Finally, 13 drugs targeting the six genes were selected as candidate drugs, which were divided into four drug–gene interaction types, and 12 of them had initial drug indications approved by the FDA. The potential gene targets of the drugs on this list are IL-6 (one drug) and IL-1β (two drugs), MMP9 (one drug), VEGFA (three drugs), TGFB1 (one drug), and EGFR (five drugs). These drugs might be used to treat CTD-PAH.

Conclusion: We identified 13 drugs targeting six genes that may have potential therapeutic effects on CTD-PAH.

Novel Genetic and Molecular Pathways in Pulmonary Arterial Hypertension Associated with Connective Tissue Disease

Pulmonary Arterial Hypertension (PAH) is a severe complication of Connective Tissue Disease (CTD), with remarkable morbidity and mortality. However, the molecular and genetic basis of CTD-PAH remains incompletely understood. This study aimed to screen for genetic defects in a cohort of patients with CTD-PAH, using a PAH-specific panel of 35 genes. During recruitment, 79 patients were studied, including 59 Systemic Sclerosis patients (SSc) and 69 females. Disease-associated variants were observed in nine patients: 4 pathogenic/likely pathogenic variants in 4 different genes (TBX4, ABCC8, KCNA5 and GDF2/BMP9) and 5 Variants of Unknown Significance (VUS) in 4 genes (ABCC8, NOTCH3, TOPBP1 and CTCFL). One patient with mixed CTD had a frameshift pathogenic variant in TBX4. Two patients with SSc-PAH carried variants in ABCC8. A patient diagnosed with Systemic Lupus Erythematous (SLE) presented a pathogenic nonsense variant in GDF2/BMP9. Another patient with SSc-PAH presented a pathogenic variant in KCNA5. Four patients with SSc-PAH carried a VUS in NOTCH1, CTCFL, CTCFL and TOPBP1, respectively. These findings suggest that genetic factors may contribute to Pulmonary Vascular Disease (PVD) in CTD patients.

Connective Tissue Disease-Associated Pulmonary Arterial Hypertension in Southern Taiwan: A Single-Center 10-Year Longitudinal Observation Cohort

Background: Pulmonary arterial hypertension (PAH) is a life-threatening disease with different etiologies and outcomes. We aimed to explore differences in clinical features and outcomes of idiopathic PAH (iPAH) and connective tissue disease-related PAH (CTD-PAH) in Taiwanese patients and determine risk factors for mortality. Methods: We retrospectively reviewed the medical records of patients with right-sided heart catheterization-diagnosed PAH between January 2005 and December 2015. The iPAH (n = 31) and CTD-PAH (n = 14) patients were enrolled and followed until December 31, 2019. Between-group comparisons were conducted. Potential predictors of the mortality of PAH were determined using the Cox proportional hazard regression model. Results: CTD-PAH patients had higher levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) and lower predicted diffusing capacity of carbon monoxide (DLCO) than iPAH patients. The mortality rates were similar between CTD-PAH and iPAH (21.4% vs. 22.6%, p = 0.99). A mean pulmonary arterial pressure (mPAP) > 46 mmHg was a predictor of PAH-induced mortality (adjusted hazard ratio 21.8, 95% confidence interval 2.32–204.8). Conclusions: A higher mPAP level, but not underlying CTDs, imposed a significantly increased risk of mortality to patients with PAH.

Morphological signs of connective tissue dysplasia as predictors of frequent post-exercise musculoskeletal disorders

Background

Connective tissue dysplasia (CTD) is a risk factor for musculoskeletal disorders. Changes caused by disorganization of collagen and elastin fibers lead to the inability of withstanding heavy mechanical stress. In clinical practice, diagnosis of these disorders depends on physical and anthropomorphic evaluation.

Methods

Forty-eight patients with frequent post-exercise musculoskeletal disorders were evaluated for CTD. The control group included 36 healthy participants. Both groups were evaluated via therapeutic examination with assessment of anthropometric indicators and physical-physiological evaluation, surveying and gathering of anamnesis. Based on testing results, study participants were evaluated on CTD presence and risk factors.

Results

All experimental group patients had connective tissue dysplasia of moderate and severe degree, with a total score of 49.44 ± 13.1. Certain morphological characteristics showed prevalence, allowing to determine pathognomonic predictors of high predisposition to frequent post-exercise musculoskeletal disorders. Back pain (100%), asthenic syndrome and kyphotic spinal deformation (75%), high gothic palate, hypermobility of joints and the auricles, excessive elasticity (63%), varicose veins of the lower extremities (56%) and hemorrhoids (56%), changes in the shape of the legs and temporomandibular joint (50%) showed to be significant clinical factors indicating possible connective tissue dysplasia.

Conclusions

The presence of these diagnostically significant morphological signs of CTD in humans is a pathognomonic predictor of a high predisposition to frequent injuries. Their early detection helps promote proper appointment of adequate physical activity regimen and develop treatment for the underlying cause.

The Influence of Connective Tissue Disease in Breast Reconstruction: A National Database Analysis

BACKGROUND

Patients with connective tissue diseases (CTD), or collagen vascular diseases, are at risk of potentially higher morbidity after surgical procedures. We aimed to investigate the complication profile in CTD versus non-CTD patients who underwent breast reconstruction on a national scale.

METHODS

A retrospective analysis of the Healthcare Cost and Utilization Project NIS Database between 2010 and 2014 was conducted for patients 18 years or older admitted for immediate autologous or implant breast reconstruction. Connective tissue disease was defined as systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis, scleroderma, Raynaud phenomenon, psoriatic arthritis, or sarcoidosis. Independent t test/Wilcoxon-Mann-Whitney was used to compare continuous variables and Pearson χ/Fischer exact test was used for categorical variables. Outcomes of interest were assessed using multivariable linear regressions for continuous variables and multivariable logistic regressions for categorical variables.

RESULTS

There were 19,496 immediate autologous breast reconstruction patients, with 357 CTD and 19,139 non-CTD patients (2010-2014). The CTD patients had higher postoperative complication rates for infection (2.8% vs 0.8%, P < 0.001), wound dehiscence (1.4% vs 0.4%, P = 0.019), and bleeding (hemorrhage and hematoma) (6.7% vs 3.5%, P < 0.001). After multivariable analysis, CTD remained an independent risk factor for bleeding (odds ratio [OR], 1.568; 95% confidence interval [CI], 1.019-2.412). There were a total of 23,048 immediate implant breast reconstruction patients, with 431 CTD and 22,617 non-CTD patients (2010-2014). The CTD patients had a higher postoperative complication rate for wound dehiscence/complication (2.3% vs 0.6%, P < 0.001). They also experienced a longer length of stay (2.31 days vs 2.07 days, P < 0.001). After multivariable analysis, CTD remained an independent risk factor for wound dehiscence (OR, 4.084; 95% CI, 2.101-7.939) and increased length of stay by 0.050 days (95% CI, -0.081 to 0.181).

CONCLUSIONS

Connective tissue disease patients who underwent autologous breast reconstruction had significantly higher infection, wound dehiscence, and bleeding rates, and those who underwent implant breast reconstruction had significantly higher wound dehiscence rates. Connective tissue diseases appear to be an independent risk factor for bleeding and wound dehiscence in autologous and implant breast reconstruction, respectively. This information may help clinicians be aware of this increased risk when determining patients for reconstruction.

Pulmonary manifestations of systemic lupus erythematosus and Sjögren's syndrome

PURPOSE OF REVIEW

Systemic lupus erythematosus (SLE) and Sjögren syndrome are chronic autoimmune inflammatory disorders that can present with multiorgan involvement including the lungs. This review will focus on recent literature pertaining to the epidemiology, pathogenesis, clinical presentation and diagnosis and management of SLE and Sjögren syndrome-associated pulmonary conditions.

RECENT FINDINGS

Pulmonary manifestations of both disease entities have been well characterized and lung involvement can be observed during the course of the disease in most cases. Pulmonary manifestations of SLE and Sjögren syndrome can be classified based on anatomical site of involvement; and the large and small airways, lung parenchyma, lung vasculature, pleura and respiratory muscles can be involved. The pleura is most commonly involved in SLE, whereas the airways are most commonly involved in primary Sjögren's syndrome (pSS). Sleep disturbances have also been described in both entities.

SUMMARY

Although further research into treatment strategies for the pulmonary complications seen in SLE and pSS is needed, the clinician should be aware of the risk factors and clinical presentation of the various pulmonary complications in SLE and pSS in order to identify patients who should be screened and/or have modifications in treatment strategies to mitigate the morbidity and mortality associated with these complications.

miR-29b in regulating blood pressure and cardiac function in the rat model of hypertension

The possibility of micro ribonucleic acid-29b (miR-29b) regulating blood pressure and cardiac function in the rat model of hypertension was investigated. Sixty rat models of hypertension were established and randomly divided into the lentivirus group (n=20), the negative lentivirus group (n=20) and the control group (n=20). Rats in the lentivirus group were injected with the recombinant lentivirus, and those in the negative lentivirus and control groups were injected with the negative control virus and infection enhancement solution, respectively. The systolic pressure of rats was monitored using the tail-cuff method, and changes in the cardiac function of rats were evaluated via high-frequency ultrasound. At 3 weeks after virus infection, rats were weighed and sacrificed, the heart was taken and the left ventricular mass index was calculated. Moreover, the expression of miR-29b in myocardial tissues was detected via reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The systolic pressure in the lentivirus group was significantly decreased compared with those in the negative lentivirus and control groups (P<0.05). In the lentivirus group, the systolic pressure was significantly reduced after virus transfection (P<0.05), and there were also statistically significant differences in ultrasonic measurement indexes (LVPWT, IVST, LVEDD and LVESD) (P<0.05). LVPWT was remarkably decreased at 5 weeks and 6 weeks compared with that in the previous week, and it was lower than those in the other two groups (all P<0.05). After virus transfection, IVST in the lentivirus group showed a decreasing trend, which was obviously lower than those in the other two groups (P<0.05). After virus transfection, LVEDD in the lentivirus group increased gradually, and was higher than that in the other two groups. The expression of miR-29b was upregulated in the lentivirus group compared with those in the other two groups (P<0.05). The overexpression of miR-29b can reduce the blood pressure and significantly improve the cardiac function of hypertension rats.

Differential expression of hepatocyte growth factor in patients with systemic sclerosis-associated pulmonary arterial hypertension

Introduction

Non-invasive biomarkers are needed to identify pulmonary arterial hypertension (PAH) in systemic sclerosis (SSc) patients who may benefit from early intervention. We sought to identify novel cytokines that differentiate patients with incident SSc-PAH from those at high risk for PAH.

Methods

The Pulmonary Hypertension Assessment and Recognition of Outcomes in Scleroderma (PHAROS) Registry is a multicenter registry of SSc patients at high risk for PAH (at-risk) or with incident right-heart catheterization-confirmed PAH (definite PAH). Serum from 10 at-risk and 9 definite PAH patients were profiled with Bio-PlexTM bead arrays for 48 cytokines and chemokines. We also evaluated the longitudinal change in cytokine profiles from 3 at-risk patients who subsequently developed definite PAH.

Results

Clinical features of at-risk versus definite PAH patients were not significantly different except for right-ventricular systolic pressure on echocardiogram (34 ± 7 vs. 45 ± 8 mmHg, p = 0.006), left atrial diameter (2.9 ± 0.5 vs. 3.7 ± 0.4 cm, p = 0.02), 6-minute walk distance (508 ± 115 vs. 393 ± 70 m, p = 0.02), mean pulmonary artery pressure (18 ± 4 vs. 32 ± 6 mmHg, p = 0.01), and pulmonary vascular resistance (111 ± 48 vs. 272 ± 109 dyn/s/cm5, p = 0.009). Serum cytokine profiling identified hepatocyte growth factor (HGF) as the only cytokine significantly different between the at-risk and definite PAH groups (225.8 ± 55.0 vs. 361.6 ± 164.5 pg/mL, q<0.1%). Profiling of longitudinal samples of at-risk to definite PAH patients did not identify any significant changes in HGF or other cytokines over time.

Conclusions

Definite PAH patients expressed higher levels of HGF than at-risk patients. Further studies are needed to clarify the utility of HGF as a predictive biomarker for SSc-PAH.

Inhibition of endocan attenuates monocrotaline-induced connective tissue disease related pulmonary arterial hypertension

Connective tissue disease related pulmonary arterial hypertension (CTD-PAH) is characterized by vascular remodeling, endothelial dysfunction and inflammation. Endocan is a novel endothelial dysfunction marker. The aim of the present study was to investigate the role of endocan in CTD-PAH. Monocrotaline (MCT)-induced PAH rats were used as the CTD-PAH model. Short hairpin RNA packed in a lentiviral vector used to inhibit endocan expression was intratracheally instilled in rats prior to the MCT injection. Endocan was found to be increased in the serum and lung of MCT-induced PAH rats. Short hairpin RNA mediated knockdown of endocan significantly decreased right ventricular systolic pressure, attenuated pulmonary remodeling and inflammatory responses in the lung. In the in vitro study, tumor necrosis factor-α (TNF-α) exposure caused increased endocan expression in the primary cultured rat pulmonary microvascular endothelial cells (RPMECs). Endocan knockdown inhibited the permeability increase and adhesion molecules secretion in RPMECs induced by TNF-α. In addition, TNF-α induced MAPK activation was blocked when endocan gene was knocked down. These data demonstrate that endocan may play an important role in the development of CTD-PAH. This study provides novel evidence to better understand the pathogenesis of CTD-PAH, which may be beneficial for the treatment of this disease.

Role of oxidized lipids in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a multifactorial disease characterized by interplay of many cellular, molecular, and genetic events that lead to excessive proliferation of pulmonary cells, including smooth muscle and endothelial cells; inflammation; and extracellular matrix remodeling. Abnormal vascular changes and structural remodeling associated with PAH culminate in vasoconstriction and obstruction of pulmonary arteries, contributing to increased pulmonary vascular resistance, pulmonary hypertension, and right ventricular failure. The complex molecular mechanisms involved in the pathobiology of PAH are the limiting factors in the development of potential therapeutic interventions for PAH. Over the years, our group and others have demonstrated the critical implication of lipids in the pathogenesis of PAH. This review specifically focuses on the current understanding of the role of oxidized lipids, lipid metabolism, peroxidation, and oxidative stress in the progression of PAH. This review also discusses the relevance of apolipoprotein A-I mimetic peptides and microRNA-193, which are known to regulate the levels of oxidized lipids, as potential therapeutics in PAH.

Endothelial to mesenchymal transition (EndoMT) in the pathogenesis of Systemic Sclerosis-associated pulmonary fibrosis and pulmonary arterial hypertension. Myth or reality?

Systemic Sclerosis (SSc) is a systemic autoimmune disease characterized by progressive fibrosis of skin and multiple internal organs and severe functional and structural microvascular alterations. SSc is considered to be the prototypic systemic fibrotic disorder. Despite currently available therapeutic approaches SSc has a high mortality rate owing to the development of SSc-associated interstitial lung disease (ILD) and pulmonary arterial hypertension (PAH), complications that have emerged as the most frequent causes of disability and mortality in SSc. The pathogenesis of the fibrotic process in SSc is complex and despite extensive investigation the exact mechanisms have remained elusive. Myofibroblasts are the cells ultimately responsible for tissue fibrosis and fibroproliferative vasculopathy in SSc. Tissue myofibroblasts in SSc originate from several sources including expansion of quiescent tissue fibroblasts and tissue accumulation of CD34+ fibrocytes. Besides these sources, myofibroblasts in SSc may result from the phenotypic conversion of endothelial cells into activated myofibroblasts, a process known as endothelial to mesenchymal transition (EndoMT). Recently, it has been postulated that EndoMT may play a role in the development of SSc-associated ILD and PAH. However, although several studies have described the occurrence of EndoMT in experimentally induced cardiac, renal, and pulmonary fibrosis and in several human disorders, the contribution of EndoMT to SSc-associated ILD and PAH has not been generally accepted. Here, the experimental evidence supporting the concept that EndoMT plays a role in the pathogenesis of SSc-associated ILD and PAH will be reviewed.

Leukotriene B4 Activates Pulmonary Artery Adventitial Fibroblasts in Pulmonary Hypertension

A recent study demonstrated a significant role for leukotriene B4 (LTB4) causing pulmonary vascular remodeling in pulmonary arterial hypertension. LTB4 was found to directly injure luminal endothelial cells and promote growth of the smooth muscle cell layer of pulmonary arterioles. The purpose of this study was to determine the effects of LTB4 on the pulmonary adventitial layer, largely composed of fibroblasts. Here, we demonstrate that LTB4 enhanced human pulmonary artery adventitial fibroblast proliferation, migration, and differentiation in a dose-dependent manner through its cognate G-protein-coupled receptor, BLT1. LTB4 activated human pulmonary artery adventitial fibroblast by upregulating p38 mitogen-activated protein kinase as well as Nox4-signaling pathways. In an autoimmune model of pulmonary hypertension, inhibition of these pathways blocked perivascular inflammation, decreased Nox4 expression, reduced reactive oxygen species production, reversed arteriolar adventitial fibroblast activation, and attenuated pulmonary hypertension development. This study uncovers a novel mechanism by which LTB4 further promotes pulmonary arterial hypertension pathogenesis, beyond its established effects on endothelial and smooth muscle cells, by activating adventitial fibroblasts.