Increased Alveolar Concentration of Nitric Oxide Is Related to Serum-induced Lung Fibroblast Proliferation in Patients with Systemic Sclerosis

Coadministration of 3'5-dimaleamylbenzoic acid and quercetin decrease pulmonary fibrosis in a systemic sclerosis model

Systemic sclerosis (SSc) is an autoimmune disease characterized by microvascular compromise and fibrosis. Pulmonary fibrosis, a prominent pulmonary complication in SSc, results in impaired lung function due to excessive accumulation of extracellular matrix components. This study aimed to investigate the effects of coadministration of 3'5-dimaleamylbenzoic acid (AD) and quercetin (Q) on key events in the development and maintenance of pulmonary fibrosis in a bleomycin (BLM)-induced SSc mouse model. The model was induced in CD1 mice through BLM administration using osmotic mini pumps. Subsequently, mice were treated with AD (6 mg/kg) plus Q (10 mg/kg) and sacrificed at 21 and 28 days post BLM administration. Histopathological analysis was performed by hematoxylin and eosin staining and Masson's trichrome staining. Immunohistochemistry was used to determine the expression of proliferation, proinflammatory, profibrotic and oxidative stress markers. The coadministration of AD and Q during the fibrotic phase of the BLM-induced SSc model led to attenuated histological alterations and pulmonary fibrosis, reflected in the recovery of alveolar spaces (30 %, p < 0.01) and decreased collagen deposits (50 %, p < 0.001). This effect was achieved by decreasing the expression of the proliferative markers cyclin D1 (87 %, p < 0.0001) and PCNA (43 %, p < 0.0001), inflammatory markers COX-2 (71 %, p < 0.0001) and iNOS (84 %, p < 0.0001), profibrotic markers α-SMA (80 %, p < 0.0001) and TGF-β (81 %, p < 0.0001) and the lipid peroxidation marker 4-HNE (43 %, p < 0.01). The antifibrotic effect of this combined therapy is associated with the regulation of proliferation, inflammation and oxidative stress, mechanisms involved in the development and progression of the fibrotic process. Our novel therapeutic strategy is the first approach to propose the use of the combination of prooxidant and antioxidant compounds as a potential strategy for SSc-associated pulmonary fibrosis.

Clinical Utility of Central and Peripheral Airway Nitric Oxide in Aging Patients with Stable and Acute Exacerbated Chronic Obstructive Pulmonary Disease

Purpose

Exhaled nitric oxide has been used as a marker of airway inflammation. The NO concentration in the central and peripheral airway/alveolar can be measured by a slow and fast exhalation flow rate to evaluate inflammation in different divisions within the respiratory tract. We hypothesized that FeNO₂₀₀ (exhaled NO at a flow rate of 200mL/s) could be used as an evaluation tool for peripheral airway/alveolar inflammation and corticosteroid therapy in chronic obstructive pulmonary disease (COPD) patients.

Methods

We recruited 171 subjects into the study: 73 healthy controls, 59 stable COPD patients, and 39 acute exacerbations of COPD (AECOPD) patients. Exhaled nitric oxide (FeNO₅₀ (exhaled NO at a flow rate of 50mL/s)), FeNO₂₀₀ and CaNO (peripheral concentration of NO/alveolar NO) and clinical variables including pulmonary function, COPD Assessment Test (CAT), C-reactive protein concentration (CRP) and circulating eosinophil count were measured among the recruited participants. FeNO_50, FeNO₂₀₀ and CaNO were repeatedly evaluated in 39 AECOPD patients after corticosteroid treatment.

Results

FeNO₂₀₀ was significantly higher in stable COPD and AECOPD patients than in healthy controls. Nevertheless, CaNO could not differentiate COPD from healthy controls. No correlation was found between circulating eosinophil counts or FEV1 and exhaled nitric oxide (FeNO_50, FeNO₂₀₀, CaNO) in COPD patients. For AECOPD patients, 64% of patients had eosinophil counts >100 cells/µL; 59% of patients had FeNO₂₀₀ >10 ppb; only 31% of patients had FeNO₅₀ > 25 ppb. Among AECOPD patients, the high FeNO₅₀ and FeNO₂₀₀ groups’ levels were significantly lower than their baseline levels, and significant improvements in CAT were seen in the two groups after corticosteroid treatment. These implied a good corticosteroid response in AECOPD patients with FeNO₂₀₀>10ppb.

Conclusion

FeNO₂₀₀ is a straightforward and feasible method to evaluate the peripheral NO concentration in COPD. FeNO200 can be a type 2 inflammation biomarker and a useful tool for predicting corticosteroid therapy in COPD.

Clinical Values of Nitric Oxide Parameters from the Respiratory System

BACKGROUND

Fractional exhaled nitric oxide (FENO) concentration reliably reflects central airway inflammation, but it is not sensitive to changes in the NO dynamics in the lung periphery. By measuring FENO at several different flow rates one can estimate alveolar NO concentration (C_ANO), bronchial NO flux (J_awNO), bronchial wall NO concentration (C_awNO) and the bronchial diffusivity of NO (D_awNO).

OBJECTIVE

We aimed to describe the current knowledge and clinical relevance of NO parameters in different pulmonary diseases.

METHODS

We conducted a systematic literature search to identify publications reporting NO parameters in subjects with pulmonary or systemic diseases affecting the respiratory tract. A narrative review was created for those with clinical relevance.

RESULTS

Estimation of pulmonary NO parameters allows for differentiation between central and peripheral inflammation and a more precise analysis of central airway NO output. C_ANO seems to be a promising marker of parenchymal inflammation in interstitial lung diseases and also a marker of tissue damage and altered gas diffusion in chronic obstructive pulmonary disease and systemic diseases affecting the lung. In asthma, C_ANO can detect small airway involvement left undetected by ordinary FENO measurement. Additionally, C_awNO and D_awNO can be used in asthma to assess if FENO is increased due to enhanced inflammatory activity (increased C_awNO) or tissue changes related to bronchial remodelling (altered D_awNO).

CONCLUSION

NO parameters may be useful for diagnosis, prediction of disease progression and prediction of treatment responses in different parenchymal lung and airway diseases. Formal trials to test the added clinical value of NO parameters are needed.

Extended Exhaled Nitric Oxide Analysis in Interstitial Lung Diseases: A Systematic Review

Fractional exhaled nitric oxide (FeNO) is a well-known and widely accepted biomarker of airways inflammation that can be useful in the therapeutic management, and adherence to inhalation therapy control, in asthmatic patients. However, the multiple-flows assessment of FeNO can provide a reliable measurement of bronchial and alveolar production of NO, supporting its potential value as biomarker also in peripheral lung diseases, such as interstitial lung diseases (ILD). In this review, we first discuss the role of NO in the pathobiology of lung fibrosis and the technique currently approved for the measurement of maximum bronchial flux of NO (J'awNO) and alveolar concentration of NO (CaNO). We systematically report the published evidence regarding extended FeNO analysis in the management of patients with different ILDs, focusing on its potential role in differential diagnosis, prognostic evaluation and severity assessment of disease. The few available data concerning extended FeNO analysis, and the most common comorbidities of ILD, are explored too. In conclusion, multiple-flows FeNO analysis, and CaNO in particular, appears to be a promising tool to be implemented in the diagnostic and prognostic pathways of patients affected with ILDs.

Deciphering the Potential Pharmaceutical Mechanism of GUI-ZHI-FU-LING-WAN on Systemic Sclerosis based on Systems Biology Approaches

Systemic sclerosis (SSc; scleroderma) is a complicated idiopathic connective tissue disease with seldom effective treatment. GUI-ZHI-FU-LING-WAN (GFW) is a classic Traditional Chinese Medicine (TCM) formula widely used for the treatment of SSc. However, the mechanism of how the GFW affects SSc remains unclear. In this study, the system biology approach was utilized to analyze herb compounds and related targets to get the general information of GFW. The KEGG enrichment analysis of 1645 related targets suggested that the formula is involved in the VEGF signaling pathway, the Toll-like receptor signaling pathway, etc. Quantitative and qualitative analysis of the relationship among the 3 subsets (formula targets, drug targets and disease genes) showed that the formula targets overlapped with 38.0% drug targets and 26.0% proteins encoded by disease genes. Through the analysis of SSc related microarray statistics from the GEO database, we also validated the consistent expression behavior among the 3 subsets before and after treatment. To further reveal the mechanism of prescription, we constructed a network among 3 subsets and decomposed it into 24 modules to decipher how GFW interfere in the progress of SSc. The modules indicated that the intervention may come into effect through following pathogenic processes: vasculopathy, immune dysregulation and tissue fibrosis. Vitro experiments confirmed that GFW could suppress the proliferation of fibroblasts and decrease the Th1 cytokine (TNF-α, MIP-2 and IL-6) expression for lipopolysaccharide (LPS) and bleomycin (BLM) stimulation in macrophages, which is consistent with previous conclusion that GFW is able to relieve SSc. The systems biology approach provides a new insight for deepening understanding about TCM.

Exhaled Nitric Oxide in Systemic Sclerosis Lung Disease

Background. Exhaled nitric oxide (eNO) is a potential biomarker to distinguish systemic sclerosis (SSc) associated pulmonary arterial hypertension (PAH) and interstitial lung disease (ILD). We evaluated the discriminative validity, feasibility, methods of eNO measurement, and magnitude of differences across lung diseases, disease-subsets (SSc, systemic lupus erythematosus), and healthy-controls. Methods. Consecutive subjects in the UHN Pulmonary Hypertension Programme were recruited. Exhaled nitric oxide was measured at 50 mL/s intervals using chemiluminescent detection. Alveolar and conducting airway NO were partitioned using a two-compartment model of axial diffusion (CMAD) and the trumpet model of axial diffusion (TMAD). Results. Sixty subjects were evaluated. Using the CMAD model, control subjects had lower median (IQR) alveolar NO than all PAH subjects (2.0 (1.5, 2.5) versus 3.14 ppb (2.3, 4.0), p = 0.008). SSc-ILD had significantly lower median conducting airway NO compared to controls (1009.5 versus 1342.1 ml⁎ppb/s, p = 0.04). SSc-PAH had increased median (IQR) alveolar NO compared to controls (3.3 (3.0, 5.7) versus 2.0 ppb (1.5, 2.5), p = 0.01). SSc-PAH conducting airway NO inversely correlated with DLCO (r -0.88 (95% CI -0.99, -0.26)). Conclusion. We have demonstrated feasibility, identified that CMAD modeling is preferred in SSc, and reported the magnitude of differences across cases and controls. Our data supports discriminative validity of eNO in SSc lung disease.

Increased exhaled nitric oxide precedes lung fibrosis in two murine models of systemic sclerosis

Exhaled nitric oxide (NO) is increased as a result of lung inflammation, which in turn causes subsequent interstitial lung disease in patients with systemic sclerosis (SSc). However, the exact time course of inflammatory and fibrotic changes in the SSc lung has not yet been described. Our objective was to assess the chronological evolution of lung inflammatory and fibrotic processes in mice pre-treated with hypochlorous acid (HOCl) or bleomycin. C57BL/6 mice were randomized into three groups receiving subcutaneous injections of HOCl, bleomycin, or PBS for 2, 4 or 6 weeks. Exhaled NO (eNO) was measured at the end of each injection period and after 2 resting weeks without injection (8 week group). Mice were then sacrificed to obtain skin and lung tissues to measure fibrotic changes and NO synthases (NOS) expression. Increased eNO, inducible NOS and nitrotyrosine expression in bronchial epithelium, lung neutrophils and macrophages were observed at early phases in both HOCl- and bleomycin-treated mice. Conversely, lung vascular endothelial NOS expression decreased significantly at 6th and 8th weeks. Skin fibrosis was significantly increased from the 4th week and lung fibrosis from 6th week. We conclude that lung inflammation occurs early after injury as reflected by increased exhaled NO and inducible NOS expression, and precedes fibrotic changes in skin and lungs of mice pre-treated with bleomycin and HOCl. Early detection and treatment of pulmonary inflammation might be useful in preventing subsequent occurrence of lung fibrosis in SSc patients.

[Use of pulmonary function tests and biomarkers studies to diagnose and follow-up interstitial lung disease in systemic sclerosis]

Interstitial lung disease (ILD) is becoming one of the main causes of death of patients with systemic sclerosis (SSc). The prevalence of ILD associated with SSc (SSc-ILD) varies from 33% to 100% according to diagnostic methods. Clinical features such as dyspnea on exertion, dry cough, and chest pains are not specific and usually late-appearing, implying more specific tests in the diagnostic, prognosis, and follow-up of ILD in patients with SSc. High resolution thoracic CT scanner (HRCT) is more sensitive than chest X-ray in the detection of SSc-ILD. Pulmonary function tests (PFT) are non-invasive and periodically used to assess the impacts of SSc on respiratory function. Diagnostic values of bronchoalveolar lavage and histological examination on lung biopsy are controversial. However, these techniques are essential for studying cellular and molecular mechanisms underlying the pathophysiology of SSc-ILD. Several biomarkers such as surfactant-A (SP-A), -D (SP-D), mucin-like high molecular weight glycoprotein (KL-6), and chemokine CCL-18 have been implicated in SSc-PID. Serum levels of these proteins are correlated with the severity of SSc-ILD, as assessed by HRCT and/or PFT. Finally, alveolar concentration of exhaled nitric oxide can be used to screen SSc patients with high risk of deterioration of respiratory function, in whom immunosuppressant treatment could be useful in preventing the evolution to irreversible lung fibrosis.

Reduced levels of S-nitrosothiols in plasma of patients with systemic sclerosis and Raynaud's phenomenon

Objective

S-Nitrosothiols (RSNOs) are bioactive forms of nitric oxide which are involved in cell signalling and redox regulation of vascular function. Circulating S-nitrosothiols are predominantly in the form of S-nitrosoalbumin. In this study plasma concentrations of S-nitrosothiols were measured in patients with systemic sclerosis (SSc) where NO metabolism is known to be abnormal.

Patients and methods

Venous blood was collected from 16 patients with Raynaud's phenomenon (RP), 45 with systemic sclerosis (SSc) (34 patients had limited SSc (IcSSc) and 11 diffuse cutaneous disease (dcSSc)). Twenty six healthy subjects were used as controls. Plasma S-nitrosothiol concentrations were measured by chemiluminescence. The measurements were related to the extent of biological age, capillary/skin scores and disease duration.

Results

Plasma RSNO levels in patients with Raynaud's phenomenon (RP) and in those with SSc was significantly lower compared to the concentrations in control subjects. In SSc, plasma S-nitrosothiols were often below the level of detection (1nM).

Conclusions

Low S-nitrosothiol concentrations were observed in the blood of patients with SSc and patients with RP indicating a profound disturbance of nitric oxide metabolism.

Characterization of the phenotype of high collagen-producing fibroblast clones in systemic sclerosis, using a new modified limiting-dilution method

BACKGROUND

Overproduction of type I collagen in fibroblasts of systemic sclerosis (SSc) is the hallmark of fibrosis. Establishment and characterization of the phenotype of SSc fibroblasts has been hindered by the heterogeneity between fibroblasts and the lack of adequate cloning methods.

AIM

To establish and investigate the characteristics of the SSc high collagen-producing fibroblast phenotype.

METHODS

Primary cultured fibroblasts from skin biopsies of patients with SSc and normal controls were cloned by a new modified limiting-dilution method. All clones were divided into different subpopulations based on their α1(I) procollagen (COL1A1) mRNA level detected by real-time reverse transcriptase PCR assay. In the different subpopulations, cell growth and cycle distribution were analysed by MTT and flow cytometry, COL1A1 promoter activity was examined by transient transfection, and the binding activity of Sp1 to the COL1A1 proximal promoter was investigated by quantitative chromatin immunoprecipitation.

RESULTS

The clonogenicities of SSc and normal control fibroblasts were similar, but the mean COL1A1 mRNA level of clones and the percentage of the subpopulation with a high COL1A1 mRNA level were significantly higher in SSc fibroblasts than in controls. There was no significant difference on cell growth and cycle between different subpopulations of SSc and control fibroblasts. The COL1A1 proximal promoter activity and its binding activity to Sp1 in the clones were strongly correlated with their COL1A1 mRNA level.

CONCLUSION

Overproduction of collagen in an SSc fibroblast subpopulation seems to result mainly from the abnormally activated transcription of COL1A1 rather than from overproliferation of fibroblasts. The new modified limiting-dilution method provides a useful means for characterizing cells with heterogeneous phenotypes.