Circulating concentration of markers of angiogenic activity in patients with sarcoidosis and idiopathic pulmonary fibrosis

Follistatin-respiratory connection predicting all-cause mortality among community-dwelling middle-to-old age individuals: Results from the I-Lan Longitudinal Study

OBJECTIVES

The link between aging and pulmonary function decline is well-established, but the underlying mechanisms have yet to be fully revealed. Serum follistatin, a myokine implicated in muscle degeneration, may play a role in age-related pulmonary changes. This study aims to investigate the relationship between serum follistatin levels and pulmonary function decline in community-dwelling older adults, and evaluate their combined association with all-cause mortality.

RESEARCH DESIGN AND METHODS

This longitudinal cohort study utilized data from 751 participants aged ≥50 years in the I-Lan Longitudinal Aging Study between 2018-2019. Serum follistatin levels, spirometry results, demographic and clinical data were retrieved. Participants were stratified based on their follistatin levels. Survival curves and group comparisons based on follistatin levels and decline in peak expiratory flow (PEF) using Kaplan-Meier analysis and log-rank tests. Multivariate Cox proportional hazards models were further used to identify independent predictors of all-cause mortality during the 52-month follow-up.

RESULTS

Elevated follistatin levels significantly correlated with worse pulmonary function, particularly decreased PEF (p = 0.030). Kaplan-Meier analysis revealed the combination of elevated follistatin levels and decreased PEF was associated with increased risk of all-cause mortality (Log-rank p = 0.023). Cox proportional hazards models further identified that concurrent presence of higher follistatin levels and decreased PEF predicted higher risk of all-cause mortality (adjusted HR 3.58, 95% CI: 1.22-10.53, p = 0.020).

CONCLUSION

Higher serum follistatin levels correlate with decreased pulmonary function, specifically PEF decline, in community-dwelling older adults. Furthermore, the coexistence of elevated follistatin levels and decreased PEF was associated with risk of all-cause mortality. Follistatin may serve as a biomarker for pulmonary aging and related adverse outcomes.

Integrative single-cell analysis of cardiac and pulmonary sarcoidosis using publicly available cardiac and bronchoalveolar lavage fluid sequencing datasets

Introduction

Cardiac presentation of autoimmune sarcoidosis, known as cardiac sarcoidosis (CS), is a poorly understood disease with high mortality and low diagnosis rate. While CS is an immunological syndrome, little is known about how cardiac parenchymal and stromal cells mediate its pathogenesis. Moreover, while most current sarcoidosis research is based on research in pulmonary sarcoidosis (PS), it remains unclear how much both presentations of sarcoidosis overlap. To tackle these concerns, we leveraged publicly available sarcoidosis transcriptomic datasets.

Methods

Two publicly available bronchoalveolar lavage single-cell RNA sequencing datasets were integrated to analyze PS relative to control. Additionally, two publicly available cardiac single-nucleus RNA sequencing datasets were integrated to analyze CS relative to control. Following integration, we ran cell-cell communication, transcription factor, and differential expression analyses on parenchymal, stromal, and immune subsets identified in our analysis.

Results

Our analysis revealed that there was an expansion of stromal and immune cells in PS and CS. We also observed upregulation of Th17.1 and attenuated activation transcriptional profiles in the immune cells of CS and PS relative to control. Additionally, we found upregulation of pro-inflammatory and pro-fibrotic transcriptional profiles in the cardiac stromal cells of CS relative to control. We also found that cardiomyocytes exhibited upregulated cardiac stress and proliferation transcriptional profiles in CS relative to control.

Conclusions

Our integrative transcriptomic analysis shows that despite tissue-specific differences, there are shared transcriptional trends between CS and PS. It also shows that stromal and parenchymal populations exhibit transcriptional trends that could explain their pathogenic role in CS.

The endothelium in lung fibrosis: a core signaling hub in disease pathogenesis?

Pulmonary fibrosis (PF) is a progressive chronic lung disease characterized by excessive deposition of extracellular matrix (ECM) and structural destruction, associated with a severe 5-year mortality rate. The onset of the disease is thought to be triggered by chronic damage to the alveolar epithelium. Since the pulmonary endothelium is an important component of the alveolar-capillary niche, it is also affected by the initial injury. In addition to ensuring proper gas exchange, the endothelium has critical functional properties, including regulation of vascular tone, inflammatory responses, coagulation, and maintenance of vascular homeostasis and integrity. Recent single-cell analyses have shown that shifts in endothelial cell (EC) subtypes occur in PF. Furthermore, the increased vascular remodeling associated with PF leads to deteriorated outcomes for patients, underscoring the importance of the vascular bed in PF. To date, the causes and consequences of endothelial and vascular involvement in lung fibrosis are poorly understood. Therefore, it is of great importance to investigate the involvement of EC and the vascular system in the pathogenesis of the disease. In this review, we will outline the current knowledge on the role of the pulmonary vasculature in PF, in terms of abnormal cellular interactions, hyperinflammation, vascular barrier disorders, and an altered basement membrane composition. Finally, we will summarize recent advances in extensive therapeutic research and discuss the significant value of novel therapies targeting the endothelium.

Potential biomarkers for diagnosis and disease evaluation of idiopathic pulmonary fibrosis

ABSTRACT

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive lung disease characterized by progressive lung fibrogenesis and histological features of usual interstitial pneumonia. IPF has a poor prognosis and presents a spectrum of disease courses ranging from slow evolving disease to rapid deterioration; thus, a differential diagnosis remains challenging. Several biomarkers have been identified to achieve a differential diagnosis; however, comprehensive reviews are lacking. This review summarizes over 100 biomarkers which can be divided into six categories according to their functions: differentially expressed biomarkers in the IPF compared to healthy controls; biomarkers distinguishing IPF from other types of interstitial lung disease; biomarkers differentiating acute exacerbation of IPF from stable disease; biomarkers predicting disease progression; biomarkers related to disease severity; and biomarkers related to treatment. Specimen used for the diagnosis of IPF included serum, bronchoalveolar lavage fluid, lung tissue, and sputum. IPF-specific biomarkers are of great clinical value for the differential diagnosis of IPF. Currently, the physiological measurements used to evaluate the occurrence of acute exacerbation, disease progression, and disease severity have limitations. Combining physiological measurements with biomarkers may increase the accuracy and sensitivity of diagnosis and disease evaluation of IPF. Most biomarkers described in this review are not routinely used in clinical practice. Future large-scale multicenter studies are required to design and validate suitable biomarker panels that have diagnostic utility for IPF.

Lymphocyte Subsets and Pulmonary Nodules to Predict the Progression of Sarcoidosis

The search for biological markers, which allow a relatively accurate assessment of the individual course of pulmonary sarcoidosis at the time of diagnosis, remains one of the research priorities in this field of pulmonary medicine. The aim of our study was to investigate possible prognostic factors for pulmonary sarcoidosis with a special focus on cellular immune inflammation markers. A 2-year follow-up of the study population after the initial prospective and simultaneous analysis of lymphocyte activation markers expression in the blood, as well as bronchoalveolar lavage fluid (BALF) and lung biopsy tissue of patients with newly diagnosed pulmonary sarcoidosis, was performed. We found that some blood and BAL fluid immunological markers and lung computed tomography (CT) patterns have been associated with a different course of sarcoidosis. We revealed five markers that had a significant negative association with the course of sarcoidosis (worsening pulmonary function tests and/or the chest CT changes)-blood CD4+CD31+ and CD4+CD44+ T lymphocytes, BALF CD8+CD31+ and CD8+CD103+ T lymphocytes and a number of lung nodules on chest CT at the time of the diagnosis. Cut-off values, sensitivity, specificity and odds ratio for predictors of sarcoidosis progression were calculated. These markers may be reasonable predictors of sarcoidosis progression.

Correlation between platelet-derived growth factor-B gene polymorphism and coronary heart disease

OBJECT

The aim of the present work was to investigate the correlation of plasma platelet-derived growth factor (PDGF)-BB level and single nucleotide polymorphism (SNP, rs1800817 and rs2285094) of PDGF-B gene with the onset and stability condition of coronary heart disease (CHD).

METHODS

Totally, 335 subjects were included in and divided into CHD (n = 247) and control group (n = 88) according to coronary angiography. Besides, the patients in the CHD group were divided into acute coronary syndrome (ACS) group (n = 165) and stable angina pectoria (SAP) group (n = 82), based on CHD stability condition. The plasma PDGF-BB level was measured by ELISA, and the genotype of PDGF-B was examined through qPCR assay.

RESULTS

The PDGF-BB level was positively correlated with hsCRP level (r = 0.149, p < 0.05). The genotype frequencies of SNP rs1800817 and rs2285094 match Hardy-Weinberg equilibrium. There was weak linkage disequilibrium between SNP rs1800817 and rs2285094: D' = 0.419, r²  = 0.04, which has no correlation with CHD. There was no statistical difference in plasma PDGF-BB level among different genotypes in rs1800817 and rs2285094. There were no differences in the plasma PDGF-BB level among patients with any genotype of SNP rs1800817 and rs2285094, no matter how it was grouped. Logistic regression results indicated that the plasma PDGF-BB level was the independent risk factor of CHD onset (OR = 1.003, 95% CI 1.001-1.006, p = 0.014).

CONCLUSIONS

High plasma PDGF-BB level is the risk factor of CHD and has correlation with instability of CHD. The plasma PDGF-BB level change may be related to inflammatory response. PDGF-B gene rs1800817 and rs2285094 polymorphisms are not correlated with CHD.

Evaluation of [68Ga]Ga-NODAGA-RGD for PET Imaging of Rat Autoimmune Myocarditis

The ⁶⁸Gallium-labeled 1,4,7-triazacyclononane-1-glutaric acid-4,7-diacetic acid conjugated radiolabelled arginine-glycine-aspartic acid peptide ([⁶⁸Ga]Ga-NODAGA-RGD) is a positron emission tomography (PET) tracer binding to cell surface receptor α_vβ₃ integrin that is upregulated during angiogenesis and inflammation. We studied whether α_vβ₃ targeting PET imaging can detect myocardial inflammation in a rat model of autoimmune myocarditis. To induce myocarditis, rats (n = 8) were immunized with porcine cardiac myosin in complete Freund's adjuvant on days 0 and 7. Control rats (n = 8) received Freund's adjuvant alone. On day 21, in vivo PET/CT imaging with [⁶⁸Ga]Ga-NODAGA-RGD followed by ex vivo autoradiography and immunohistochemistry were carried out. Inflammatory lesions were detected histologically in the myocardium of 7 out of 8 immunized rats. In vivo PET images showed higher [⁶⁸Ga]Ga-NODAGA-RGD accumulation in the myocardium of rats with inflammation than the non-inflamed myocardium of control rats (SUV_mean 0.4 ± 0.1 vs. 0.1 ± 0.02; P = 0.00006). Ex vivo autoradiography and histology confirmed that [⁶⁸Ga]Ga-NODAGA-RGD uptake co-localized with inflammatory lesions containing α_vβ₃ integrin-positive capillary-like structures. A non-specific [⁶⁸Ga]Ga-DOTA-(RGE)₂ tracer showed 76% lower uptake than [⁶⁸Ga]Ga-NODAGA-RGD in the inflamed myocardium. Our results indicate that α_vβ₃ integrin-targeting [⁶⁸Ga]Ga-NODAGA-RGD is a potential PET tracer for the specific detection of active inflammatory lesions in autoimmune myocarditis.

Pulmonary disease as a risk factor for transfusion-related acute lung injury

Transfusion-related acute lung injury (TRALI) is a severe condition characterised by noncardiogenic pulmonary oedema that develops within 6 h of blood transfusion. Patient factors and blood products have both been implicated in the development of TRALI; however, the role of pulmonary disease has not been investigated. We aimed to determine whether pulmonary disease is a risk factor for TRALI.

We conducted a nested case-control study using data from the Diagnosis Procedure Combination database, a nationwide inpatient database in Japan, between July 2010 and March 2015. Case patients who developed TRALI were 1:4-matched with control patients for sex, age and same hospital for receipt of blood transfusion. We conducted a multivariable conditional logistic regression analysis to evaluate the associations of TRALI with various factors including comorbidities, body mass index (BMI) and plasma-containing blood products.

We identified 2 019 501 hospitalised patients who received a blood transfusion. Among these patients, 72 developed TRALI. The 72 case patients had higher proportions of haematological malignancy, trauma and interstitial lung disease (ILD) than the 288 matched control patients. The multivariable conditional logistic regression analysis showed that occurrence of TRALI was associated with ILD (odds ratio, 3.88; 95% confidence interval, 1.11–13.6), BMI ≥25.0 kg·m⁻² (2.10; 1.05–4.24) and plasma-containing blood products (1.94; 1.10–3.42), but not with infectious lung disease or obstructive airway disease.

In conclusion, ILD was an independent risk factor for the development of TRALI. Physicians should be aware of the increased risk of TRALI in patients with ILD.

Physicians should be aware of the risk of developing transfusion-related acute lung injury when performing a blood transfusion in patients with interstitial lung disease.https://bit.ly/3jdoZQP

Target inhibition of galectin-3 by inhaled TD139 in patients with idiopathic pulmonary fibrosis

Galectin (Gal)-3 is a profibrotic β-galactoside-binding lectin that plays a key role in the pathogenesis of idiopathic pulmonary fibrosis (IPF) and IPF exacerbations. TD139 is a novel and potent small-molecule inhibitor of Gal-3.

A randomised, double-blind, multicentre, placebo-controlled, phase 1/2a study was conducted to assess the safety, tolerability, pharmacokinetics and pharmacodynamics of inhaled TD139 in 36 healthy subjects and 24 patients with IPF. Six dose cohorts of six healthy subjects were evaluated (4:2 TD139:placebo ratio) with single doses of TD139 (0.15–50 mg) and three dose cohorts of eight patients with IPF (5:3 TD139:placebo ratio) with once-daily doses of TD139 (0.3–10 mg) for 14 days.

Inhaled TD139 was well tolerated with no significant treatment-related side-effects. TD139 was rapidly absorbed, with mean time taken to reach maximum plasma concentration (C_max) values ranging from 0.6 to 3 h and a plasma half-life (T_1/2) of 8 h. The concentration of TD139 in the lung was >567-fold higher than in the blood, with systemic exposure predicting exposure in the target compartment. Gal-3 expression on alveolar macrophages was reduced in the 3 and 10 mg dose groups compared with placebo, with a concentration-dependent inhibition demonstrated. Inhibition of Gal-3 expression in the lung was associated with reductions in plasma biomarkers centrally relevant to IPF pathobiology (platelet-derived growth factor-BB, plasminogen activator inhibitor-1, Gal-3, CCL18 and YKL-40).

TD139 is safe and well tolerated in healthy subjects and IPF patients. It was shown to suppress Gal-3 expression on bronchoalveolar lavage macrophages and, in a concerted fashion, decrease plasma biomarkers associated with IPF progression.

TD139 is a potent inhibitor of galectin-3, a key driver of fibrosis in the lung. In this phase 1/2a clinical study, inhaled TD139 was safe, well tolerated, and demonstrated target engagement and decreased plasma biomarkers associated with IPF progression.https://bit.ly/2JREKx6

CD31+, CD38+, CD44+, and CD103+ lymphocytes in peripheral blood, bronchoalveolar lavage fluid and lung biopsy tissue in sarcoid patients and controls

Background

The mechanisms driving the transition from inflammation to fibrosis in sarcoidosis patients are poorly understood; prognostic features are lacking. Immune cell profiling may provide insights into pathogenesis and prognostic factors of the disease. This study aimed to establish associations in simultaneous of lymphocyte subset profiles in the blood, bronchoalveolar lavage fluid (BALF), and lung biopsy tissue in the patients with newly diagnosed sarcoidosis.

Methods

A total of 71 sarcoid patients (SPs) and 20 healthy controls (HCs) were enrolled into the study. CD31, CD38, CD44, CD103 positive T lymphocytes in blood and BALF were analysed. Additionally, the densities of CD4, CD8, CD38, CD44, CD103 positive cells in lung tissue biopsies were estimated by digital image analysis.

Results

Main findings: (I) increase of percentage of CD3⁺CD4⁺CD38⁺ in BALF and blood, and increase of percentage of CD3⁺CD4⁺CD44⁺ in BALF in Löfgren syndrome patients comparing with patients without Löfgren syndrome, (II) increase of percentage of CD3⁺CD4⁺103⁺ in BALF and in blood in patients without Löfgren syndrome (comparing with Löfgren syndrome patients) and increase of percentage of CD3⁺CD4⁺103⁺ in BALF and in blood in more advanced sarcoidosis stage. (III) Increasing percentage of BALF CD3⁺CD4⁺CD31⁺ in sarcoidosis patients when comparing with controls independently of presence of Löfgren syndrome, smoking status or stage of sarcoidosis. Several significant correlations were found.

Conclusions

Lymphocyte subpopulations in blood, BALF, and lung tissue were substantially different in SPs at the time of diagnosis compared to HCs. CD3⁺CD4⁺CD31⁺ in BALF might be a potential supporting marker for the diagnosis of sarcoidosis. CD3⁺CD4⁺CD38⁺ in BALF and blood and CD3⁺CD4⁺CD44⁺ in BALF may be markers of the acute immune response in sarcoidosis patients. CD4⁺CD103⁺ T-cells in BALF and in blood are markers of the persistent immune response in sarcoidosis patients and are potential prognostic features of the chronic course of this disease.

Association of proangiogenic and profibrotic serum markers with lung function and quality of life in sarcoidosis

Background

Sarcoidosis is a systemic inflammatory granulomatous disease, frequently affecting the lung. If left untreated, it may end in lung fibrosis. Proangiogenic and profibrotic vascular endothelial growth factor (VEGF), transforming growth factor (TGF)-β1, fibroblast growth factor (FGF)-2 and platelet-derived growth factor (PDGF)-AB are a known therapeutical target in pulmonary fibrosing diseases, e.g. IPF, but there is no targeted therapy option for pulmonary fibrosis in sarcoidosis.

Objectives

The aim of our study was to determine the association of these markers’ serum levels on lung function and the patients’ quality of life in a long-term follow-up of sarcoidosis patients, to provide further information for finding targeted therapy options for pulmonary sarcoidosis.

Methods

54 patients with sarcoidosis underwent blood sampling, pulmonary function testing and answered the King’s Brief Interstitial Lung Disease (K-BILD) questionnaire at baseline and at three-years follow-up. Serum levels of profibrotic and angiogenic markers were assessed at baseline by enzyme-linked immunosorbent assay.

Results

Between 2015 and 2018, 54 patients with biopsy proven sarcoidosis were enrolled. Throughout the observation period, there was a significant decrease in the diffusion capacity for carbon monoxide (DLCO) [%] (-6.5504 ± 13,39, p = 0.001) and forced expiratory volume in one second predicted (FEV1) [%] (-6.07 ± 12.09, p = 0.001). Patients with greater impairment of forced vital capacity (FVC) did have significantly higher serum levels of VEGF (p = 0.03) and PDGF-AB (p<0.001). The K-BILD questionnaire did not change significantly during follow-up. However, patients with worsening K-BILD scores did have significantly higher serum-levels of PDGF-AB (2.67 pg/ml ± 0.93 vs. 1.88 pg/ml ± 0.60, p = 0.004) at baseline, compared to those with unchanged or increasing K-BILD scores.

Conclusions

Among patients with pulmonary sarcoidosis, baseline serum levels of VEGF and PDGF-AB were associated with pulmonary function impairment. Furthermore, PDGF-AB was associated with worsening K-BILD scores. No such association was observed for FGF-2 and TGF-ß1. VEGF and PDGF-AB may be possible prognostic and therapeutic targets in sarcoidosis as a fibrosing ILD beyond IPF.

Exhaled Biomarkers in Idiopathic Pulmonary Fibrosis-A Six-Month Follow-Up Study in Patients Treated with Pirfenidone

The mechanism of action of pirfenidone in idiopathic pulmonary fibrosis (IPF) has not been fully elucidated. To offer additional insight, we evaluated the change in the cytokine profile in exhaled breath condensate (EBC) following a six-month treatment with pirfenidone in patients with IPF. EBC concentrations of interleukin (IL)-6, IL-8, IL-15, TNF-α and VEGF-A were assessed with ELISA and compared at baseline and after six months of pirfenidone treatment. Twenty-nine patients with IPF and 13 controls were evaluated at baseline. With the exception of IL-8 concentration, which was lower in patients with IPF when compared to controls (p = 0.005), the cytokine levels did not differ between the groups. Despite the use of a high sensitivity assay, IL-8 reached detectable values only in 24% of IPF patients. EBC analysis after six months of treatment with pirfenidone did not reveal any differences in the cytokine levels. The change in EBC vascular endothelial growth factor A (VEGF-A) correlated with the change in the 6 min walk distance (r = 0.54, p = 0.045). We conclude that a six-month treatment with pirfenidone did not significantly change the EBC cytokine profile. Our findings support the potential usefulness of VEGF-A as a marker in IPF. The low EBC IL-8 level in patients with IPF is a novel finding which needs confirmation in larger studies.

An Adaptogen: Withaferin A Ameliorates in Vitro and in Vivo Pulmonary Fibrosis by Modulating the Interplay of Fibrotic, Matricelluar Proteins, and Cytokines

Pulmonary fibrosis (PF) is chronic lung disease with only two FDA approved clinically available drugs, with limited safety profile. Inadequate therapy motivated us to explore the effect of vimentin inhibitor Withaferin A, as an anti-fibrotic agent against TGF-β1-induced in vitro fibrotic events and Bleomycin induced in vivo fibrosis with an emphasis on epithelial to mesenchymal transition (EMT), extracellular matrix deposition (ECM), inflammation, and angiogenesis. In vitro EMT and fibrotic events were induced by TGF-β1 in alveolar epithelial cells and human fetal lung fibroblasts followed by treatment with Withaferin A (0.25, 0.5, and 1 μM concentrations) to explore its anti-fibrotic effects. In vivo potential of Withaferin A (2 and 4 mg/kg) was assessed in murine model of Bleomycin induced PF. All the parameters and molecular studies related to PF were performed at the end of treatment period. Withaferin A treatment reduced the progression of PF by modulating the EMT related cell markers both in vivo and in vitro. Withaferin A ameliorated the expression of inflammatory cytokines including NF-κB p65, IL-1β and TNF-α, as well as attenuated the expression of pro-fibrotic proteins including CTGF, collagen 1A2, collagen 3A1, and fibronectin. Expression of angiogenic factors like VEGF, FAK, p38 MAPK, and PLC-γ1 were also inhibited by Withaferin A. Phosphorylation of Smad 2/3 induced by TGF-β1 and Bleomycin were significantly inhibited. Withaferin A suppressed expression of pro-inflammatory, pro-fibrotic, and pro-angiogenic mediators and also reduced the ECM deposition. In a nutshell, Withaferin A could probably prove as an efficient and potential therapeutic against PF.

Treprostinil inhibits proliferation and extracellular matrix deposition by fibroblasts through cAMP activation

Idiopathic pulmonary fibrosis (IPF) is characterized by peripheral lung fibrosis and increased interstitial extracellular matrix (ECM) deposition. In IPF, tumor growth factor (TGF)-β1 which is the major stimulus of ECM deposition, and platelet derived growth factor (PDGF)-BB is a potent stimulus of fibrosis. Thus, the effect of Treprostinil on TGF-ß1 and PDGF-induced fibroblast proliferation and ECM deposition was investigated. Human peripheral lung fibroblasts of seven IPF patients and five lung donors were stimulated by PDGF, or TGF-β1, or the combination. Cells were pre-incubated (30 min) with either Treprostinil, forskolin, di-deoxyadenosine (DDA), or vehicle. Treprostinil time dependently activated cAMP thereby preventing PDGF-BB induced proliferation and TGF-β1 secretion. Cell counts indicated proliferation; α-smooth muscle actin (α-SMA) indicted differentiation, and collagen type-1 or fibronectin deposition remodeling. Myo-fibroblast indicating α-SMA expression was significantly reduced and its formation was altered by Treprostinil. Collagen type-I and fibronectin deposition were also reduced by Treprostinil. The effect of Treprostinil on collagen type-I deposition was cAMP sensitive as it was counteracted by DDA, while the effect on fibronectin was not cAMP mediated. Treprostinil antagonized the pro-fibrotic effects of both PDGF-BB and TGF-β1 in primary human lung fibroblasts. The data presented propose a therapeutic relevant anti-fibrotic effect of Treprostinil in IPF.

IL-8 mediates idiopathic pulmonary fibrosis mesenchymal progenitor cell fibrogenicity

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disease, but the mechanisms driving progression remain incompletely defined. We previously reported that the IPF lung harbors fibrogenic mesenchymal progenitor cells (MPCs), which serve as a cell of origin for IPF fibroblasts. Proliferating IPF MPCs are located at the periphery of fibroblastic foci in an active cellular front at the interface between the myofibroblast-rich focus core and adjacent normal alveolar structures. Among a large set of genes that distinguish IPF MPCs from their control counterparts, we identified IL-8 as a candidate mediator of IPF MPC fibrogenicity and driver of fibrotic progression. IPF MPCs and their progeny displayed increased steady-state levels of IL-8 and its cognate receptor CXCR1 and secreted more IL-8 than did controls. IL-8 functioned in an autocrine manner promoting IPF MPC self-renewal and the proliferation and motility of IPF MPC progeny. Secreted IL-8 also functioned in a paracrine manner stimulating macrophage migration. Analysis of IPF lung tissue demonstrated codistribution of IPF MPCs with activated macrophages in the active cellular front of the fibroblastic focus. These findings indicate that IPF MPC-derived IL-8 is capable of expanding the mesenchymal cell population and recruiting activated macrophages cells to actively evolving fibrotic lesions.

Mesenchymal stem cells in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a major cause of respiratory failure in critically ill patients and common outcome of various lung interstitial diseases. Its mortality remains high, and no effective pharmacotherapy, in addition to artificial ventilation and transplantation, exists. As such, the administration of mesenchymal stem or stromal cells (MSCs) is currently investigated as a new therapeutic method for pulmonary fibrosis. Clinical trials on MSC-based therapy as a potential treatment for lung injury and fibrosis are also performed. MSCs can migrate to injured sites and secrete multiple paracrine factors and then regulate endothelial and epithelial permeability, decrease inflammation, enhance tissue repair, and inhibit bacterial growth. In this review, recent studies on stem cells, particularly MSCs, involved in alleviating lung inflammation and fibrosis and their potential MSC-induced mechanisms, including migration and differentiation, soluble factor and extracellular vesicle secretion, and endogenous regulatory functions, were summarized.

Adipose tissue fibrosis in human cancer cachexia: the role of TGFβ pathway

Background

Cancer cachexia is a multifactorial syndrome that dramatically decreases survival. Loss of white adipose tissue (WAT) is one of the key characteristics of cachexia. WAT wasting is paralleled by microarchitectural remodeling in cachectic cancer patients. Fibrosis results from uncontrolled ECM synthesis, a process in which, transforming growth factor-beta (TGFβ) plays a pivotal role. So far, the mechanisms involved in adipose tissue (AT) re-arrangement, and the role of TGFβ in inducing AT remodeling in weight-losing cancer patients are poorly understood. This study examined the modulation of ECM components mediated by TGFβ pathway in fibrotic AT obtained from cachectic gastrointestinal cancer patients.

Methods

After signing the informed consent form, patients were enrolled into the following groups: cancer cachexia (CC, n = 21), weight-stable cancer (WSC, n = 17), and control (n = 21). The total amount of collagen and elastic fibers in the subcutaneous AT was assessed by histological analysis and by immunohistochemistry. TGFβ isoforms expression was analyzed by Multiplex assay and by immunohistochemistry. Alpha-smooth muscle actin (αSMA), fibroblast-specific protein (FSP1), Smad3 and 4 were quantified by qPCR and/or by immunohistochemistry. Interleukin (IL) 2, IL5, IL8, IL13 and IL17 content, cytokines known to be associated with fibrosis, was measured by Multiplex assay.

Results

There was an accumulation of collagen and elastic fibers in the AT of CC, as compared with WSC and controls. Collagens type I, III, VI, and fibronectin expression was enhanced in the tissue of CC, compared with both WSC and control. The pronounced expression of αSMA in the surrounding of adipocytes, and the increased mRNA content for FSP1 (20-fold) indicate the presence of activated myofibroblasts; particularly in CC. TGFβ1 and TGFβ3 levels were up-regulated by cachexia in AT, as well in the isolated adipocytes. Smad3 and Smad4 labeling was found to be more evident in the fibrotic areas of CC adipose tissue.

Conclusions

Cancer cachexia promotes the development of AT fibrosis, in association with altered TGFβ signaling, compromising AT organization and function.