Change in serum marker of oxidative stress in the progression of idiopathic pulmonary fibrosis

Identification of oxidative stress-related diagnostic markers and immune infiltration features for idiopathic pulmonary fibrosis by bibliometrics and bioinformatics

Idiopathic pulmonary fibrosis (IPF) garners considerable attention due to its high fatality rate and profound impact on quality of life. Our study conducts a comprehensive literature review on IPF using bibliometric analysis to explore existing hot research topics, and identifies novel diagnostic and therapeutic targets for IPF using bioinformatics analysis. Publications related to IPF from 2013 to 2023 were searched on the Web of Science Core Collection (WoSCC) database. Data analysis and visualization were conducted using CiteSpace and VOSviewer software primarily. The gene expression profiles GSE24206 and GSE53845 were employed as the training dataset. The GSE110147 dataset was employed as the validation dataset. We identified differentially expressed genes (DEGs) and differentially expressed genes related to oxidative stress (DEOSGs) between IPF and normal samples. Then, we conducted Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. The hub genes were screened by protein-protein interaction (PPI) networks and machine learning algorithms. The CIBERSORT was used to analyze the immune infiltration of 22 kinds of immune cells. Finally, we conducted the expression and validation of hub genes. The diagnostic efficacy of hub genes was evaluated by employing Receiver Operating Characteristic (ROC) curves and the associations between hub genes and immune cells were analyzed. A total of 6,500 articles were identified, and the annual number of articles exhibited an upward trend. The United States emerged as the leading contributor in terms of publication count, institutional affiliations, highly cited articles, and prolific authorship. According to co-occurrence analysis, oxidative stress and inflammation are hot topics in IPF research. A total of 1,140 DEGs were identified, and 72 genes were classified as DEOSGs. By employing PPI network analysis and machine learning algorithms, PON2 and TLR4 were identified as hub genes. A total of 10 immune cells exhibited significant differences between IPF and normal samples. PON2 and TLR4, as oxidative stress-related genes, not only exhibit high diagnostic efficacy but also show close associations with immune cells. In summary, our study highlights oxidative stress and inflammation are hot topics in IPF research. Oxidative stress and immune cells play a vital role in the pathogenesis of IPF. Our findings suggest the potential of PON2 and TLR4 as novel diagnostic and therapeutic targets for IPF.

Notch Signaling Is Associated with Pulmonary Fibrosis in Patients with Pigeon Breeder's Lung by Regulating Oxidative Stress

This study explored the molecular mechanism underlying the association of Notch signaling and oxidative stress with the occurrence of pulmonary fibrosis in patients with pigeon breeder's lung (PBL). Rat models of fibrotic PBL were constructed with freeze-dried protein powder, and the animals were divided into the control (intratracheal instillation of normal saline; n = 9), M (PBL model; intratracheal instillation of freeze-dried protein powder; n = 9), and M + D (PBL+ the Notch inhibitor DAPT; n = 9) groups. Immunohistochemistry was employed to observe the protein levels of pathway factors and α-SMA, and the levels of ROS, GSH-PX, SOD, and MDA were observed using ELISA. To verify the results of the animal experiment, cytological models were constructed. The M group and the M + D group had significantly increased α-SMA levels (P < 0.05). Although both groups had significantly higher key protein levels in the Notch channel, the M + D group had significantly lower levels relative to the M group (P < 0.05). Oxidative stress products were examined, and the levels of MDA and ROS were significantly increased, while those of GSH-PX and SOD were significantly decreased in the M and M + D groups as compared to the control, but the M group and the M + D group significantly differed (P <  0.05). These findings were further validated by the cytological experiment. Notch signaling is associated with pulmonary fibrosis in PBL by regulating cellular oxidative stress, and inhibiting this pathway can slow down pulmonary fibrosis progression.

Lipocalin-2 as a prognostic marker in patients with acute exacerbation of idiopathic pulmonary fibrosis

BACKGROUND

Lipocalin-2 (LCN2) is a secretory glycoprotein upregulated by oxidative stress; moreover, patients with idiopathic pulmonary fibrosis (IPF) have shown increased LCN2 levels in bronchoalveolar lavage fluid (BALF). This study aimed to determine whether circulatory LCN2 could be a systemic biomarker in patients with IPF and to investigate the role of LCN2 in a bleomycin-induced lung injury mouse model.

METHODS

We measured serum LCN2 levels in 99 patients with stable IPF, 27 patients with acute exacerbation (AE) of IPF, 51 patients with chronic hypersensitivity pneumonitis, and 67 healthy controls. Further, LCN2 expression in lung tissue was evaluated in a bleomycin-induced lung injury mouse model, and the role of LCN2 was investigated using LCN2-knockout (LCN2 -/-) mice.

RESULTS

Serum levels of LCN2 were significantly higher in patients with AE-IPF than in the other groups. The multivariate Cox proportional hazards model showed that elevated serum LCN2 level was an independent predictor of poor survival in patients with AE-IPF. In the bleomycin-induced lung injury mouse model, a higher dose of bleomycin resulted in higher LCN2 levels and shorter survival. Bleomycin-treated LCN2 -/- mice exhibited increased BALF cell and protein levels as well as hydroxyproline content. Moreover, compared with wild-type mice, LCN2-/- mice showed higher levels of circulatory 8-isoprostane as well as lower Nrf-2, GCLC, and NQO1 expression levels in lung tissue following bleomycin administration.

CONCLUSIONS

Our findings demonstrate that serum LCN2 might be a potential prognostic marker of AE-IPF. Moreover, LCN2 expression levels may reflect the severity of lung injury, and LCN2 may be a protective factor against bleomycin-induced acute lung injury and oxidative stress.

Identification and validation of potential biomarkers related to oxidative stress in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrotic interstitial pneumonia with a poor prognosis and a pathogenesis that has not been fully elucidated. Oxidative stress is closely associated with IPF. In this research, we aimed to identify reliable diagnostic biomarkers associated with the oxidative stress through bioinformatics techniques. The gene expression profile data from the GSE70866 dataset was retrieved from the gene expression omnibus (GEO) database. We extracted 437 oxidative stress-related genes (ORGs) from gene set enrichment analysis (GSEA). The GSE141939 dataset was used for single-cell RNA-seq analysis to identify the expression of diagnostic genes in different cell clusters. A total of 10 differentially expressed oxidative stress-related genes (DE-ORGs) were screened. Subsequently, SOD3, CD36, ACOX2, RBM11, CYP1B1, SNCA, and MPO from the 10 DE-ORGs were identified as diagnostic genes based on random forest algorithm with randomized least absolute shrinkage and selection operator (LASSO) regression. A nomogram was constructed to evaluate the risk of disease. The decision curve analysis (DCA) and clinical impact curves indicated that the nomogram based on these seven biomarkers had extraordinary predictive power. Immune cell infiltration analysis results revealed that DE-ORGs were closely related to various immune cells, especially CYP1B1 was in positive correlation with monocytes and negative correlation with macrophages M1. Single-cell RNA-seq analysis showed that CYP1B1 was mainly associated with macrophages, and SNCA was mainly associated with basal cells. CYP1B1 and SNCA were diagnostic genes associated with oxidative stress in IPF.

Superoxide dismutase secreting Bacillus amyloliquefaciens spores attenuate pulmonary fibrosis

Superoxide dismutase (SOD) can convert active oxygen to oxygen or hydrogen peroxide, and recent research has suggested that it can protect against lung damage and fibrosis. Clinical applications based on SOD remain limited however due to costs and low stability. We here investigated a potential new therapeutic delivery system for this enzyme in the form of SOD-overexpressing Bacillus amyloliquefaciens spores which we introduced into a bleomycin-induced pulmonary fibrosis mouse model. This treatment significantly alleviated the disease, as quantified using a hydroxyproline assay, at 107 colony forming unit (CFU) of Bacillus spores per day. Exposure of the mice to the spores was further found to decrease the lung mRNA levels of CTGF, Col1a1, α-SMA, TGF-β, TNF-α, and IL-6, and the protein levels of TGF-β, Smad2/3, αSMA and Col1a1, all major indicators of pulmonary fibrosis. Survival benefits, and reduced byproducts of lipid peroxidase such as malondialdehyde and 4-hydroxynen, were also noted in the treated animals. The beneficial effects of these Bacillus spores on pulmonary fibrosis were further found to be greater than the equivalent free SOD concentration. Immunofluorescence staining of primary pulmonary fibroblasts extracted from the bleomycin-induced model showed decreased αSMA expression following the in vivo treatment with SOD-overexpressing Bacillus. Our treatment approach SOD through Bacillus spores shows beneficial effects against pulmonary fibrosis, combined with the suppression of the SMAD/TGF-β pathway, suggesting that it is an effective novel delivery route for antioxidants.

Individualised Exercise Training Enhances Antioxidant Buffering Capacity in Idiopathic Pulmonary Fibrosis

Exercise training is recommended for patients with idiopathic pulmonary fibrosis (IPF); however, the mechanism(s) underlying its physiological benefits remain unclear. We investigated the effects of an individualised aerobic interval training programme on exercise capacity and redox status in IPF patients. IPF patients were recruited prospectively to an 8-week, twice-weekly cardiopulmonary exercise test (CPET)-derived structured responsive exercise training programme (SRETP). Systemic redox status was assessed pre- and post-CPET at baseline and following SRETP completion. An age- and sex-matched non-IPF control cohort was recruited for baseline comparison only. At baseline, IPF patients (n = 15) had evidence of increased oxidative stress compared with the controls as judged by; the plasma reduced/oxidised glutathione ratio (median, control 1856 vs. IPF 736 p = 0.046). Eleven IPF patients completed the SRETP (median adherence 88%). Following SRETP completion, there was a significant improvement in exercise capacity assessed via the constant work-rate endurance time (+82%, p = 0.003). This was accompanied by an improvement in post-exercise redox status (in favour of antioxidants) assessed via serum total free thiols (median increase, +0.26 μmol/g protein p = 0.005) and total glutathione concentration (+0.73 μM p = 0.03), as well as a decrease in post-exercise lipid peroxidation products (-1.20 μM p = 0.02). Following SRETP completion, post-exercise circulating nitrite concentrations were significantly lower compared with baseline (-0.39 μM p = 0.04), suggestive of exercise-induced nitrite utilisation. The SRETP increased both endurance time and systemic antioxidant capacity in IPF patients. The observed reduction in nitrite concentrations provides a mechanistic rationale to investigate nitrite/nitrate supplementation in IPF patients.

Molecular mechanism by which the Notch signaling pathway regulates autophagy in a rat model of pulmonary fibrosis in pigeon breeder's lung

This study investigated the molecular mechanisms underlying the involvement of the Notch signaling pathway and autophagy in the development of pulmonary fibrosis in pigeon breeder's lung (PBL). Rats were divided into control (Ctrl), PBL model (M), M + D (Notch signaling inhibition), M + W (autophagy inhibition), and M + R (autophagy induction) groups. Lyophilized protein powder from pigeon shedding materials was used as an allergen to construct a fibrotic PBL rat model. The mechanism by which Notch signaling regulated autophagy in the pulmonary fibrosis of PBL was investigated by inhibiting the Notch pathway and interfering with autophagy. Pulmonary interstitial fibrosis was significantly greater in the M group and the M + W group than in the M + D and M + R groups. The expression of α-smooth muscle actin was significantly higher in the M, M + D, and M + W groups than in the Ctrl group (P < 0.05). The expression of the cell autophagy markers Beclin1 and LC3 was lower in the M, M + D, and M + W groups than in the Ctrl group (P < 0.05), whereas Beclin1 and LC3 expressions were higher in the M + D and M + R groups than in the M group. The levels of reactive oxygen species in serum and lung tissues were higher in the M, M + D, M + W, and M + R groups than in the Ctrl group (P < 0.05). The Notch signaling pathway is involved in the pathological process of pulmonary fibrosis in the rat model of PBL by regulating autophagy.

Effects of n-3 polyunsaturated fatty acid supplementation on quadriceps weakness immediately after total knee arthroplasty: a pilot, randomized, open-label clinical trial

[Purpose] Severe quadriceps weakness immediately after total knee arthroplasty can be problematic. The n-3 long-chain polyunsaturated fatty acids have antioxidant and anti-inflammatory effects against ischemia-reperfusion injury, whereas n-6 long-chain polyunsaturated fatty acids exert pro-inflammatory effects, thereby promoting ischemia-reperfusion injury. [Participants and Methods] We explored the efficacy of preoperative n-3 long-chain polyunsaturated fatty acid supplementation against early quadriceps weakness among 20 patients scheduled for total knee arthroplasty (intervention group, n=10; control group, n=10). The intervention group received 645 mg of eicosapentaenoic acid) and 215 mg of docosahexaenoic acid daily for 30 days preoperatively. Serum eicosapentaenoic acid, docosahexaenoic acid, and arachidonic acid levels were measured preoperatively. We compared serum derivatives of reactive oxygen metabolites as oxidative stress biomarkers, knee circumference, thigh volume, knee pain during the quadriceps strength test, and quadriceps strength preoperatively and 4 days postoperatively to quantify the change. [Results] Preoperative n-3 long-chain polyunsaturated fatty acid supplementation significantly increased the (eicosapentaenoic acid+docosahexaenoic acid)/arachidonic acid ratio in the intervention group. A significantly lower increase in quadriceps weakness was exhibited in the intervention group than in the control group. However, changes in oxidative stress, knee/thigh swelling, and knee pain during strength testing did not significantly differ between the two groups. [Conclusion] Preoperative n-3 long-chain polyunsaturated fatty acid supplementation exhibited beneficial effects on quadriceps weakness immediately after total knee arthroplasty.

Alamandine: A promising treatment for fibrosis

Angiotensin (Ang) II, the main active member of the renin angiotensin system (RAS), is essential for the maintenance of cardiovascular homeostasis. However, hyperactivation of the RAS causes fibrotic diseases. Ang II has pro-inflammatory actions, and moreover activates interstitial fibroblasts and/or dysregulates extracellular matrix degradation. The discovery of new RAS pathways has revealed the complexity of this system. Among the RAS peptides, alamandine (ALA, Ala¹ Ang 1-7) has been identified in humans, rats, and mice, with protective actions in different pathological conditions. ALA has similar effects to its well-known congener, Ang-(1-7), as a vasodilator, anti-inflammatory, and antifibrotic. Its protective role against cardiovascular diseases is well-reviewed in the literature. However, the protective actions of ALA in fibrotic conditions have been little explored. Therefore, in this article, we review the ability of ALA to modulate the inflammatory process and collagen deposition, to serve as an antioxidant, and to mediate protection against functional disorders. In this scenario, we also explore ALA as a promising therapy for pulmonary fibrosis after COVID-19 infection.

Targeting Oxidative Stress as a Therapeutic Approach for Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic interstitial lung disease characterized by an abnormal reepithelialisation, an excessive tissue remodelling and a progressive fibrosis within the alveolar wall that are not due to infection or cancer. Oxidative stress has been proposed as a key molecular process in pulmonary fibrosis development and different components of the redox system are altered in the cellular actors participating in lung fibrosis. To this respect, several activators of the antioxidant machinery and inhibitors of the oxidant species and pathways have been assayed in preclinical in vitro and in vivo models and in different clinical trials. This review discusses the role of oxidative stress in the development and progression of IPF and its underlying mechanisms as well as the evidence of oxidative stress in human IPF. Finally, we analyze the mechanism of action, the efficacy and the current status of different drugs developed to inhibit the oxidative stress as anti-fibrotic therapy in IPF.

Hemosiderin-Laden Macrophages in Bronchoalveolar Lavage: Predictive Role for Acute Exacerbation of Idiopathic Interstitial Pneumonias

Background

Hemosiderin-laden macrophages (HLMs) have been identified in the bronchoalveolar lavage fluid (BALF) of patients with idiopathic pulmonary fibrosis (IPF). This retrospective study examined the ability of HLMs in BALF to predict the acute exacerbation (AE) of chronic idiopathic interstitial pneumonias (IIPs).

Methods

Two hundred and twenty-one patients with IIP diagnosed by bronchoscopy were enrolled in the study (IPF, n = 87; IIPs other than IPF, n = 134). Giemsa stain was used to detect HLMs in BALF specimens. Prussian blue stain was used to quantify HLMs in BALF, and a hemosiderin score (HS) was given to the specimens containing HLMs.

Results

Twenty-four patients had a positive HS (range: 7‒132). The receiver-operating characteristic curve analysis identified the cutoff HS value for predicting the AE of IIPs to be 61.5. Seven cases had a higher HS (≥61.5) and 214 had a lower HS. AE occurred significantly earlier in the higher HS group (4/7 cases) than in the lower HS group (41/214 cases) during a median observation period of 1239 days (log-rank test, p = 0.026). Multivariate Cox proportional hazard regression analysis showed that a higher HS was a significant predictor of AE in addition to IPF, percent predicted forced vital capacity, and modified Medical Research Council score. The C-statistics for the prediction of AE did not significantly improve by all the above parameters with HS as compared without HS.

Conclusions

A higher HS was a significant predictor of AE in IIPs but did not significantly improve the predictive ability of other parameters.

Intratracheally Inhalable Nifedipine-Loaded Chitosan-PLGA Nanocomposites as a Promising Nanoplatform for Lung Targeting: Snowballed Protection via Regulation of TGF-β/β-Catenin Pathway in Bleomycin-Induced Pulmonary Fibrosis

Pulmonary fibrosis is a serious ailment that may progress to lung remodeling and demolition, where the key participants in its incidence are fibroblasts responding to growth factors and cellular calcium swinging. Calcium channel blockers, like nifedipine (NFD), may represent auspicious agents in pulmonary fibrosis treatment. Unfortunately, NFD bears complicated pharmacodynamics and a diminished systemic bioavailability. Thus, the current study aimed to develop a novel, non-invasive nanoplatform for NFD for direct/effective pulmonary targeting via intratracheal instillation. A modified solvent emulsification–evaporation method was adopted for the fabrication of NFD-nanocomposites, integrating poly(D,L-lactide-co-glycolide) (PLGA), chitosan (CTS), and polyvinyl alcohol, and optimized for different physiochemical properties according to the 3² full factorial design. Additionally, the aerodynamic behavior of the nanocomposites was scrutinized through cascade impaction. Moreover, the pharmacokinetic investigations were conducted in rats. Furthermore, the optimum formulation was tested in bleomycin-induced pulmonary fibrosis in rats, wherein fibrotic and oxidative stress parameters were measured. The optimum nanocomposites disclosed a nanosized spherical morphology (226.46 nm), a high entrapment efficiency (61.81%) and a sustained release profile over 24 h (50.4%). As well, it displayed a boosted in vitro lung deposition performance with a mass median aerodynamic diameter of 1.12 µm. Pharmacokinetic studies manifested snowballed bioavailability of the optimal nanocomposites by 3.68- and 2.36-fold compared to both the oral and intratracheal suspensions, respectively. The intratracheal nanocomposites revealed a significant reduction in lung fibrotic and oxidative stress markers notably analogous to normal control besides repairing abnormality in TGF-β/β-catenin pathway. Our results conferred a compelling proof-of-principle that NFD-CTS-PLGA nanocomposites can function as a promising nanoparadigm for pulmonary fibrosis management.

Oxidative Stress and Abnormal Tendon Sonographic Features in Elite Soccer Players (A Pilot Study)

Objective  Sound experimental data suggest that oxidative stress plays an important role in the pathogenesis of tendinopathies. However, this hypothesis in humans remains speculative given that clinical data are lacking to confirm it. Recently, a new methodology has allowed to quantify the oxidative stress in vivo by measuring the concentration of hydroperoxides of organic compounds, which have been utilized as an oxidative stress-related marker in several pathologic and physiologic conditions. Given the reliability of this test and the lack of information in subjects with tendinopathies, the aim of the present study was to assess the oxidative stress status in elite professional soccer players with and without ultrasonographic features of tendon damage.

Methods  In 73 elite players, blood metabolic parameters were evaluated and oxidative stress was measured by means of a specific test (expressed as U-Carr units). Therefore, an ultrasonographic evaluation of the Achilles and patellar tendons was performed.

Results  No significant relationships were observed between metabolic parameters and oxidative stress biomarkers. The Achilles and patellar tendons showed a normal echographic pattern in 58 athletes, and sonographic abnormalities in 15. The athletes with ultrasonographic alterations, compared to those with normal US picture, showed significantly higher U-Carr levels ( p  = 0.000), body mass index (BMI) values ( p  = 0.03) and were older ( p  = 0.005). The difference in U-Carr values among the subjects remained significant also after adjustment for age and BMI.

Conclusion  The results of the present study support the hypothesis that oxidative substances, also increased at systemic and not only at local level, may favor tendon damage.

Level of Evidence  IV (pilot study).

Association between Preoperative Long-Chain Polyunsaturated Fatty Acids and Oxidative Stress Immediately after Total Knee Arthroplasty: A Pilot Study

Quadriceps muscle atrophy following total knee arthroplasty (TKA) can be caused by tourniquet-induced ischemia–reperfusion (IR) injury, which is often accompanied by oxidative stress and inflammatory responses. n-3 long-chain polyunsaturated fatty acids (LCPUFAs), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), exert antioxidant and anti-inflammatory effects against IR injury, whereas n-6 LCPUFAs, particularly arachidonic acid (AA), exhibit pro-inflammatory effects and promote IR injury. This study aimed to examine whether preoperative serum EPA + DHA levels and the (EPA + DHA)/AA ratio are associated with oxidative stress immediately after TKA. Fourteen eligible patients with knee osteoarthritis scheduled for unilateral TKA participated in this study. The levels of serum EPA, DHA, and AA were measured immediately before surgery. Derivatives of reactive oxygen metabolites (d-ROMs) were used as biomarkers for oxidative stress. The preoperative serum EPA + DHA levels and the (EPA + DHA)/AA ratio were found to be significantly negatively correlated with the serum d-ROM levels at 96 h after surgery, and the rate of increase in serum d-ROM levels between baseline and 96 h postoperatively. This study suggested the preoperative serum EPA + DHA levels and the (EPA + DHA)/AA ratio can be negatively associated with oxidative stress immediately after TKA.

Molecular Biomarkers in Idiopathic Pulmonary Fibrosis: State of the Art and Future Directions

Idiopathic pulmonary fibrosis (IPF), the most lethal form of interstitial pneumonia of unknown cause, is associated with a specific radiological and histopathological pattern (the so-called "usual interstitial pneumonia" pattern) and has a median survival estimated to be between 3 and 5 years after diagnosis. However, evidence shows that IPF has different clinical phenotypes, which are characterized by a variable disease course over time. At present, the natural history of IPF is unpredictable for individual patients, although some genetic factors and circulating biomarkers have been associated with different prognoses. Since in its early stages, IPF may be asymptomatic, leading to a delayed diagnosis. Two drugs, pirfenidone and nintedanib, have been shown to modify the disease course by slowing down the decline in lung function. It is also known that 5-10% of the IPF patients may be affected by episodes of acute and often fatal decline. The acute worsening of disease is sometimes attributed to identifiable conditions, such as pneumonia or heart failure; but many of these events occur without an identifiable cause. These idiopathic acute worsenings are termed acute exacerbations of IPF. To date, clinical biomarkers, diagnostic, prognostic, and theranostic, are not well characterized. However, they could become useful tools helping facilitate diagnoses, monitoring disease progression and treatment efficacy. The aim of this review is to cover molecular mechanisms underlying IPF and research into new clinical biomarkers, to be utilized in diagnosis and prognosis, even in patients treated with antifibrotic drugs.

Liproxstatin-1 alleviates bleomycin-induced alveolar epithelial cells injury and mice pulmonary fibrosis via attenuating inflammation, reshaping redox equilibrium, and suppressing ROS/p53/α-SMA pathway

With undetermined etiology and limited treatment option, idiopathic pulmonary fibrosis (IPF) an age related disease is extremely lethal. Persistent injury of epithelial cells, abnormal activation of fibroblasts/myofibroblasts, and superabundant deposition of extracellular matrix protein pathologically characterize IPF. Redox imbalance is reported to play a vital role in both IPF development and senescence. This study aim to investigate whether and how Liproxstatin-1 (Lip-1), a strong lipid autoxidation inhibitor, regulates bleomycin (BLM) induced pulmonary fibrosis both in vivo and in vitro. It's demonstrated that Lip-1 exerted a potent anti-fibrotic function in BLM-induced mice pulmonary fibrosis via alleviating inflammatory, reshaping redox equilibrium, and ameliorating collagen deposition. Lip-1 reduced the level of reactive oxygen species (ROS) and methane dicarboxylic aldehyde (MDA), promoted the expression of glutathione (GSH), catalase (CAT), and total superoxide dismutase (T-SOD) after BLM treatment. Moreover, in vitro experiments verified that Lip-1 protected A549 cells from BLM-induced injury and fibrosis. Lip-1 seemed to attenuate BLM-induced fibrosis by targeting ROS/p53/α-SMA signaling both in vivo and in vitro. In summary, this study demonstrates that Lip-1 administration performs a protective role in against pulmonary fibrosis and lights up the potential of Lip-1 treatment for patient with IPF in future.

The Effects of Chronic Intermittent Hypoxia in Bleomycin-Induced Lung Injury on Pulmonary Fibrosis via Regulating the NF-κB/Nrf2 Signaling Pathway

Background

Obstructive sleep apnea (OSA) is associated with pulmonary fibrosis. Chronic intermittent hypoxia (CIH) is considered to be a surrogate of OSA. However, its exact role in pulmonary fibrosis remains uncertain. Therefore, we investigated the mechanism underlying CIH-induced pulmonary fibrosis and the role of the anti-fibrotic agent in bleomycin (BLE) induced lung injury.

Methods

Mice were divided into eight groups: the normoxia (NOR), CIH, NOR plus BLE, CIH plus BLE, NOR plus pirfenidone (PF), CIH plus PF, NOR plus BLE and PF, and CIH plus BLE and PF groups. BLE was administered intratracheally on day 14 following CIH or NOR exposure. Subsequently, the mice were exposed to CIH or NOR for an additional 4 weeks. PF was administered orally on day 5 after BLE instillation once daily for 3 weeks.

Results

In the BLE-treated groups, CIH-induced more collagen deposition in lung tissues than NOR, and significantly increased hydroxyproline and transforming growth factor-β expression. The CIH and BLE-treated groups showed increased lung inflammation compared to NOR or CIH groups. Following CIH with BLE treatment, nuclear factor-κB (NF-κB) protein expression was significantly increased, whereas nuclear factor-erythroid-related factor 2 (Nrf2) and heme oxygenase-1 protein levels were decreased. After PF treatment, NF-κB and Kelch-like ECH-associated protein 1 expression were suppressed, and Nrf2 expression was increased.

Conclusion

CIH accelerated lung fibrosis in BLE-induced lung injury in mice, potentially by regulating the NF-κB/Nrf2 signaling pathway. Our results implicate PF as a potential therapeutic agent for treating pulmonary fibrosis in individuals with OSA and idiopathic pulmonary fibrosis.

Serum biomarker CA 15-3 as predictor of response to antifibrotic treatment and survival in idiopathic pulmonary fibrosis

Aim: Cancer antigen 15-3 (CA 15-3) is a baseline biomarker in idiopathic pulmonary fibrosis (IPF), but its value during follow-up is unknown. Materials and methods: Associations between serum CA 15-3 and pulmonary function tests during 1-year follow-up were evaluated by a mixed model in 132 IPF treated with pirfenidone or nintedanib. Results: Increased baseline (median: 56 kU/l) and follow-up CA 15-3 levels were inversely associated with forced vital capacity and diffusing capacity of the lung for carbon monoxide (estimates respectively: -5.21 and -4.69; p < 0.001). Baseline and 6-month CA 15-3 above 58.5 (hazard ratio: 1.67; p = 0.031) and 50.5 kU/l (hazard ratio: 2.99; p < 0.001), respectively, showed impaired survival compared with lower levels. Conclusion: CA 15-3 is associated with pulmonary function test during follow-up in IPF on antifibrotic treatment. Higher (follow-up) values are related with poor survival. Therefore, CA 15-3 is a promising follow-up biomarker in IPF.

Krebs von den Lungen-6 as a biomarker for disease severity assessment in interstitial lung disease: a comprehensive review

Aim: Interstitial lung diseases (ILD) are a group of lung disorders characterized by interstitial lung thickening. Krebs von den Lungen-6 (KL-6) is a molecule that is predominantly expressed by damaged alveolar type II cells and it has been proposed as a potential biomarker of different ILD. Materials & methods: A growing literature about KL-6 has been reviewed and selected to evaluate its role in the clinical management of ILD to predict disease diagnosis, activity, prognosis and treatment response. Results: KL-6 concentrations have been evaluated in fibrotic and granulomatous lung diseases and it was demonstrated to be a biomarker of disease severity useful for clinical follow-up of ILD patients. KL-6 levels differentiated between fibrotic ILD, such as idiopathic pulmonary fibrosis and chronic hypersensitivity pneumonitis, and nonfibrotic lung disorders, including sarcoidosis and pulmonary alveolar proteinosis. Conclusion: KL-6 is predictive biomarker useful in the clinical management of ILD patients, in particular in patients with severe fibrotic lung disorders.

Circulating lung biomarkers in idiopathic lung fibrosis and interstitial lung diseases associated with connective tissue diseases: Where do we stand?

Interstitial lung diseases (ILDs) are complex diseases with various courses where personalized medicine is highly expected. Biomarkers are indicators of physiological, pathological processes or of pharmacological response to therapeutic interventions. They can be used for diagnosis, risk-stratification, prediction and monitoring of treatment response. To better delineate the input and pitfalls of biomarkers in ILDs, we performed a systematic review and meta-analysis of literature in MEDLINE and Embase databases from January 1960 to February 2019. We focused on circulating biomarkers as having the highest generalizability. Overall, 70 studies were included in the review and 20 studies could be included in the meta-analysis. This review highlights that ILD associated with connective tissue diseases (CTD-ILD) and idiopathic pulmonary fibrosis (IPF) share common biomarkers, suggesting common pathophysiological pathways. KL-6 and SP-D, could diagnose lung fibrosis in both IPF and CTD-ILD, with KL-6 having the strongest value (OR: 520.95[110.07-2465.58], p<0.001 in IPF and OR:26.43[7.15-97.68], p<0.001 in CTD-ILD), followed by SPD (OR: 33.81[3.20-357.52], p = 0.003 in IPF and 13.24 [3.84-45.71] in SSc-ILD), MMP7 appeared as interesting for IPF diagnosis (p<0.001), whereas in SSc, CCL18 was associated with ILD diagnosis. Both CCL18 and KL-6 were predictive for the outcomes of ILDs, with higher predictive values for CCL18 in both IPF (OR:10.22[4.72-22.16], p<0.001 and in SSc [2.62[1.71-4.03], p<0.001). However, disease specific biomarkers are lacking and large longitudinal studies are needed before the translational use of the potential biomarkers in clinical practice. With the recent availability of new effective therapies in ILDs, further studies should assess response to treatment.

Serum oxidative stress in patients with pulmonary Mycobacterium avium complex disease

Background

The mechanism of progressive airway destruction in incurable chronic infection of the lung – termed pulmonary Mycobacterium avium complex (pMAC) disease – is currently unknown. The involvement of oxidative stress in a variety of progressive chronic respiratory diseases has been previously reported. It has been hypothesized that oxidative stress may be involved in the progression of airway destruction in pMAC disease.

Patients and methods

The study included 28 untreated patients with pMAC disease. The level of serum oxidative stress was quantitatively evaluated through the diacron reactive oxygen metabolites (d-ROMs) test, which indirectly measures the level of hydroperoxide in the serum. In addition, patients were divided into three groups based on the severity shown in the computed tomographic image.

Results

The level of serum oxidative stress exceeded the normal range (250–300 U.Carr [Carratelli Units]) in all patients with pMAC disease (mean: 495.5 ± 102.6 U.Carr; minimum–maximum: 340–734 U.Carr). The level of serum oxidative stress in patients with severe disease was significantly higher compared with that observed in patients with mild disease (434.6 ± 30.2 vs. 583.4 ± 95.1, respectively, p = 0.009).

Conclusions

In patients with pMAC disease, an elevation was observed in the level of serum oxidative stress. This increase in oxidative stress was more pronounced in patients with severe disease.

Current advances in idiopathic pulmonary fibrosis: the pathogenesis, therapeutic strategies and candidate molecules

Idiopathic pulmonary fibrosis (IPF) is a type of chronic, progressive lung disease with unknown cause, which is characterized by increasing dyspnea and destruction of lung function with a high mortality rate. Evolving evidence demonstrated that the pathogenesis of IPF involved multiple signaling pathways such as inflammation, oxidative stress and fibrosis. However, drug discovery to prevent or revert IPF has been insufficient to cope with the development. Drug discovery targeting multiple links should be considered. In this review, we will brief the pathogenesis of IPF and discuss several small chemical entities toward the pathogenesis for IPF studied in animal models and clinical trials. The field of novel anti-IPF agents and the future directions for the prevention and treatment of IPF are detailed thoroughly discussed.

Pembrolizumab-induced interstitial lung disease following thoracic surgery in a patient with non-small cell lung cancer

The safety of treatment with immune‐checkpoint inhibitors prior to thoracic surgery in patients with non‐small cell lung cancer (NSCLC) remains unclear. Here, we describe the case of a 62‐year‐old woman with NSCLC with programmed death ligand 1 expression on 85% of tumor cells. The patient was initially considered to have unresectable stage IIIB disease and received pembrolizumab monotherapy. After 12 cycles of pembrolizumab, the primary tumor was reduced, but a small lung nodule in another lobe was unchanged. Based on the course of image findings, the nodule was considered to be an old inflammatory change. The clinical stage was changed to stage IB and partial resection was performed. Three days after thoracic surgery, the patient began to complain of coughing and shortness of breath. A CT of the chest revealed ground‐glass opacity in the bilateral lung fields, suggesting interstitial lung disease (ILD) associated with pembrolizumab. Corticosteroid therapy was started and a chest X‐ray showed a reduction in the opacity with improved oxygenation. This is the first case of immune‐checkpoint inhibitor‐related ILD triggered by thoracic surgery following long‐term immune‐checkpoint therapy.

Expression of TRB3 promotes epithelial‑mesenchymal transition of MLE‑12 murine alveolar type II epithelial cells through the TGF‑β1/Smad3 signaling pathway

The aim of the present study was to investigate whether the expression of tribbles pseudokinase 3 (TRB3) is involved in pulmonary interstitial fibrosis and to examine the possible mechanisms. The expression of TRB3 in murine alveolar type II epithelial cells (MLE‑12 cells) following transforming growth factor β1 (TGF‑β1) stimulation was assessed using various techniques, including western blot and reverse transcription‑quantitative polymerase chain reaction assays. TRB3 overexpression and downregulation models were used to evaluate the impact of TRB3 on the TGF‑β1‑induced epithelial‑mesenchymal transition (EMT) of MLE‑12 cells. The downregulation of TRB3 was induced by RNA interference. The expression of TRB3 was significantly increased in MLE‑12 cells following the activation of TGF‑β1 (P<0.05). The overexpression of TRB3 was found to promote activation of the TGF‑β1/Smad3 signaling pathway, EMT, and the upregulated expression of β‑catenin and EMT‑related genes and proteins (P<0.05), whereas the downregulation of TRB3 attenuated the promoting effect on EMT induced by TGF‑β1. In addition, the overexpression of TRB3 inhibited MLE‑12 cell proliferation by stimulating apoptosis, leading to the formation of pulmonary fibrosis (PF). The positive feedback loop demonstrated that TGF‑β1 induced the expression of TRB3, and TRB3, in turn, stimulated EMT and promoted the onset of PF through activation of the TGF‑β1/Smad3 signaling pathway. Therefore, TRB3 may promote the formation of PF through the TGF‑β1/Smad3 signaling pathway.

Antioxidant Activity Mediates Pirfenidone Antifibrotic Effects in Human Pulmonary Vascular Smooth Muscle Cells Exposed to Sera of Idiopathic Pulmonary Fibrosis Patients

Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease characterized by an exacerbated fibrotic response. Although molecular and cellular determinants involved in the onset and progression of this devastating disease are largely unknown, an aberrant remodeling of the pulmonary vasculature appears to have implications in IPF pathogenesis. Here, we demonstrated for the first time that an increase of reactive oxygen species (ROS) generation induced by sera from IPF patients drives both collagen type I deposition and proliferation of primary human pulmonary artery smooth muscle cells (HPASMCs). IPF sera-induced cellular effects were significantly blunted in cells exposed to the NADPH oxidase inhibitor diphenyleneiodonium (DPI) proving the causative role of ROS and suggesting their potential cellular source. Contrary to IPF naive patients, sera from Pirfenidone-treated IPF patients failed to significantly induce both ROS generation and collagen synthesis in HPASMCs, mechanistically implicating antioxidant properties as the basis for the in vivo effect of this drug.

Oxidative stress-linked biomarkers in idiopathic pulmonary fibrosis: a systematic review and meta-analysis

AIM

The aim of this meta-analysis was to investigate associations between idiopathic pulmonary fibrosis (IPF) and markers of oxidative stress (OS) measured in different biological samples.

METHODS

A systematic search of publications listed in PubMed, Web of Science, Scopus and Google Scholar from inception to December 2017 was conducted.

RESULTS

Significant differences between IPF patients and controls were observed for all biomarkers (thiobarbituric acid reactive substances, hydroperoxides and glutathione), barring systemic isoprostanes.

CONCLUSION

This meta-analysis showed a consistent increase in the concentrations of OS markers or a reduction in antioxidant markers, in patients with IPF, independent of the type of biological sample. Pending the results of further studies, OS biomarkers might be useful for the diagnosis and monitoring of IPF.

A Chinese Herbal Formula Ameliorates Pulmonary Fibrosis by Inhibiting Oxidative Stress via Upregulating Nrf2

This study aimed to explore the protective effects of a Chinese herbal formula, Jinshui Huanxian formula (JHF), on experimental pulmonary fibrosis and its underlying mechanisms. After being treated with single dose of bleomycin (5 mg/kg) intratracheally, rats were orally administered with JHF and pirfenidone from day 1 to 42, then sacrificed at 7, 14, 28, or 42 days post-bleomycin instillation. JHF ameliorated bleomycin-induced pathological changes, collagen deposition in the rat lung and recovered pulmonary function at different days post-bleomycin instillation. In lungs of JHF-treated rats, the levels of total superoxide dismutase, catalase and glutathione were higher, and myeloperoxidase and methane dicarboxylic aldehyde were lower than those in vehicle-treated rats, respectively. Additionally, JHF inhibited the expression of NADPH oxidase 4 (NOX4) and increased the Nuclear Factor Erythroid 2-Related Factor 2 (Nrf2) in lung tissues. In vitro, JHF and ruscogenin, a compound of Ophiopogonis Radix contained in JHF, significantly inhibited transforming growth factor β1 (TGF-β1)-induced differentiation of fibroblasts. Furthermore, JHF markedly decreased the level of reactive oxygen species in TGF-β1-induced fibroblast. In line with this, upregulation of NAD(P)H: quinone oxidoreductase 1 and heme oxygenase 1, and downregulation of NOX4 were found in JHF-treated fibroblast induced by TGF-β1. While on the other hand, Nrf2 siRNA could suppress the JHF-mediated inhibition effect on alpha-smooth muscle actin (α-SMA), and FN1 expression induced by TGF-β₁ in fibroblasts. These results indicated that JHF performed remarkably therapeutic and long-term effects on pulmonary fibrosis in rat and suppressed the differentiation of fibroblast into myofibroblast through reducing the oxidative response by upregulating Nrf2 signaling. It might provide a new potential natural drug for the treatment of pulmonary fibrosis.

Nutritional status and muscle dysfunction in chronic respiratory diseases: stable phase versus acute exacerbations

Nutritional abnormalities are frequent in different chronic respiratory diseases such as chronic obstructive pulmonary disease (COPD), bronchiectasis, cystic fibrosis (CF), interstitial fibrosis and lung cancer, having important clinical consequences. However, nutritional abnormalities often remained underdiagnosed due to the relative lack of awareness of health professionals. Therefore, systematic anthropometry or even better, assessment of body composition, should be performed in all patients with chronic respiratory conditions, especially following exacerbation periods when malnutrition becomes more accentuated. Nutritional abnormalities very often include the loss of muscle mass, which is an important factor for the occurrence of muscle dysfunction. The latter can be easily detected with the specific assessment of muscle strength and endurance, and also negatively influences patients' quality of life and prognosis. Both nutritional abnormalities and muscle dysfunction result from the interaction of several factors, including tobacco smoking, low physical activity-sedentarism, systemic inflammation and the imbalance between energy supply and requirements, which essentially lead to a negative balance between protein breakdown and synthesis. Therapeutic approaches include improvements in lifestyle, nutritional supplementation and training. Anabolic drugs may be administered in some cases.

Evaluation of oxidative stress biomarkers in idiopathic pulmonary fibrosis and therapeutic applications: a systematic review

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF), a fatal lung disease of unknown origin, is characterized by chronic and progressive fibrosing interstitial pneumonia which progressively impairs lung function. Oxidative stress is one of the main pathogenic pathways in IPF. The aim of this systematic review was to describe the type of markers of oxidative stress identified in different biological specimens and the effects of antioxidant therapies in patients with IPF.

METHODS

We conducted a systematic search of publications listed in electronic databases (Pubmed, Web of Science, Scopus and Google Scholar) from inception to October 2017. Two investigators independently reviewed all identified articles to determine eligibility.

RESULTS

After a substantial proportion of the initially identified articles (n = 554) was excluded because they were duplicates, abstracts, irrelevant, or did not meet the selection criteria, we identified 30 studies. In each study, we critically appraised the type, site (systemic vs. local, e.g. breath, sputum, expired breath condensate, epithelial lining fluid, bronchoalveolar lavage, and lung tissue specimens), and method used for measuring the identified oxidative stress biomarkers. Furthermore, the current knowledge on antioxidant therapies in IPF was summarized.

CONCLUSIONS

A number of markers of oxidative stress, with individual advantages and limitations, have been described in patients with IPF. Nevertheless, trials of antioxidant treatments have been unable to demonstrate consistent benefits, barring recent pharmacogenomics data suggesting different results in specific genotype subgroups of patients with IPF.

F2-isoprostanes can mediate bleomycin-induced lung fibrosis

F₂-isoprostanes (F₂-IsoPs) have been considered markers of oxidative stress in various pulmonary diseases, but little is known about their possible role in pulmonary fibrosis. In this study, we have investigated the potential key role of F₂-IsoPs as markers and mediators of bleomycin (BLM)-induced pulmonary fibrosis in rats. During the in vivo study, plasma F₂-IsoPs showed a peak at 7 days and remained elevated for the entire experimental period. Lung F₂-IsoP content nearly tripled 7 days following the intratracheal instillation of BLM, and by 28 days, the value increased about fivefold compared to the controls. Collagen deposition correlated with F₂-IsoP content in the lung. Furthermore, from day 21 onwards, lung sections from BLM-treated animals showed α-smooth muscle actin (α-SMA) positive cells, which were mostly evident at 28 days. In vitro studies performed in rat lung fibroblasts (RLF) demonstrated that either BLM or F₂-IsoPs stimulated both cell proliferation and collagen synthesis. Moreover, RLF treated with F₂-IsoPs showed a significant increase of α-SMA expression compared to control, indicating that F₂-IsoPs can readily activate fibroblasts to myofibroblasts. Our data demonstrated that F₂-IsoPs can be mediators of key events for the onset and development of lung fibrosis, such as cell proliferation, collagen synthesis and fibroblast activation. Immunocytochemistry analysis, inhibition and binding studies demonstrated the presence of the thromboxane A₂ receptor (TP receptor) on lung fibroblasts and suggested that the observed effects may be elicited through the binding to this receptor. Our data added a new perspective on the role of F₂-IsoPs in lung fibrosis by providing evidence of a profibrotic role for these mediators in the pathogenesis of pulmonary fibrosis.

Treatment effects of the traditional Chinese medicine Shenks in bleomycin-induced lung fibrosis through regulation of TGF-beta/Smad3 signaling and oxidative stress

Pulmonary fibrosis is a kind of devastating interstitial lung disease due to the limited therapeutic strategies. Traditional Chinese medicine (TCM) practices have put forth Shenks as a promising treatment approach. Here, we performed in vivo study and in vitro study to delineate the anti-fibrotic mechanisms behind Shenks treatment for pulmonary fibrosis. We found that regardless of the prophylactic or therapeutic treatment, Shenks was able to attenuate BLM-induced-fibrosis in mice, down regulate extracellular matrix genes expression, and reduce collagen production. The aberrantly high Smad3 phosphorylation levels and SBE activity in TGF-β-induced fibroblasts were dramatically decreased as a result of Shenks treatment. At the same time, Shenks was able to increase the expression of antioxidant-related genes, including Gclc and Ec-sod, while reduce the transcription levels of oxidative-related genes, such as Rac1 and Nox4 demonstrated by both in vivo and in vitro studies. Further investigations found that Shenks could decrease the oxidative productions of protein (3-nitrotyrosine) and lipid (malondialdehyde) and increase GSH content both in bleomycin treated mouse lungs and TGF-β stimulated fibroblasts, as well as inhibit the production of ROS stimulated by TGF-β to fight against oxidative stress. Overall, Shenks inhibited fibrosis by blocking TGF-β pathway and modulating the oxidant/antioxidant balance.

Pirfenidone attenuates bleomycin-induced pulmonary fibrosis in mice by regulating Nrf2/Bach1 equilibrium

Background

Oxidative stress is one of the important factors involved in the pathogenesis of idiopathic pulmonary fibrosis (IPF). The equilibrium of Nuclear factor-erythroid-related factor 2 (Nrf2)/[BTB (broad-complex, tramtrack and bric-a-brac) and CNC (cap‘n’collar protein) homology 1, Bach1] determines the expression level of antioxidant factors, further regulating the function of oxidation/antioxidation capacity. Pirfenidone (PFD) is one of two currently for IPF therapy approved drugs. PFD regulates intracellular antioxidants, inhibits secretion of inflammatory cytokines and collagen synthesis. However the mechanisms of its antioxidant effects remain elusive.

Methods

Effects of PFD treatment were studied in mouse lung fibroblasts (MLF) following induction by transforming-growth factor beta 1 (TGF-β1) and in mice following bleomycin-induced lung fibrosis. The mRNA and protein levels of oxidative stress-related factors Nrf2/Bach1 and their downstream antioxidant factors heme oxygenase-1 (Ho-1) and glutathione peroxidase 1 (Gpx1) were determined by RT-PCR and Western blot. Fibrosis-related cytokines interleukin-6 (IL-6) and myofibroblast markers type 1 collagen α1 (COL1A1) levels in supernate of MLF, serum, and bronchoalveolar lavage fluid (BALF) as well as malondialdehyde (MDA) in serum and BALF were detected by ELISA, reactive oxygen species (ROS) generation was measured by 2′,7′- dichlorofluorescin diacetate (DCFH-DA) assay and lung pathological/morphological alterations in mice were observed by HE and Masson to assess the antioxidant mechanism and therapeutic effects on pulmonary fibrosis induced by bleomycin.

Results

PFD inhibited Bach1 mRNA and protein expressions in mouse lung fibroblasts induced by TGF-β1 and lung tissues with pulmonary fibrosis induced by bleomycin. Furthermore, it improved Nrf2, Ho-1 and Gpx1 mRNA and protein expressions. After PFD treatment, COL1A1and IL-6 levels in supernate of MLF, serum, and BALF as well as ROS in lung tissues and MDA in serum and BALF from a mouse with pulmonary fibrosis were significantly decreased, and the infiltration of lung inflammatory cells and fibrosis degree were alleviated.

Conclusions

Theraputic effects of PFD for IPF were involved in Nrf2/Bach1 equilibrium which regulated the capacity of oxidative stress. The study provided new insights into the antioxidant mechanism of PFD.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-017-0405-7) contains supplementary material, which is available to authorized users.

The Application of a Modified d-ROMs Test for Measurement of Oxidative Stress and Oxidized High-Density Lipoprotein

Reactive oxygen species (ROS) are involved in the initiation and progression of atherosclerosis. ROS-derived hydroperoxides, as an indicator of ROS production, have been measured by using the diacron reactive oxygen metabolites (d-ROMs) test, which requires iron-containing transferrin in the reaction mixture. In this study we developed a modified d-ROMs test, termed the Fe-ROMs test, where iron ions were exogenously added to the reaction mixture. This modification is expected to exclude the assay variation that comes from different blood iron levels in individuals. In addition, this Fe-ROMs test was helpful for determining the class of plasma lipoproteins that are hydroperoxidized. Low-density lipoprotein/very low-density lipoprotein (LDL/VLDL) and high-density lipoprotein (HDL) were purified by use of an LDL/VLDL purification kit and the dextran sulfate-Mg²⁺ precipitation method, respectively; their hydroperoxide contents were assessed by performing the Fe-ROMs test. The majority of the hydroperoxides were detected only in the HDL fraction, not in the LDL/VLDL. Further detailed analysis of HDLs by size-exclusion high-performance liquid chromatography revealed that the hydroperoxide-containing molecules were small-sized HDLs. Because HDL was shown to be the principal vehicle for the plasma hydroperoxides, this Fe-ROMs test is a beneficial method for the assessment of oxidized-HDL levels. Indeed, Fe-ROMs levels were strongly associated with the levels of oxidized HDL, which were determined by performing the malondialdehyde-modified HDL enzyme immunoassay. In conclusion, the Fe-ROMs test using plasma itself or the HDL fraction after dextran sulfate-Mg²⁺ precipitation is useful to assess the functionality of HDL, because the oxidation of HDL impairs its antiatherogenic capacity.

Bach1 siRNA attenuates bleomycin-induced pulmonary fibrosis by modulating oxidative stress in mice

Oxidative stress plays an essential role in inflammation and fibrosis. Bach1 is an important transcriptional repressor that acts by modulating oxidative stress and represents a potential target in the treatment of pulmonary fibrosis (PF). In this study, we knocked down Bach1 using adenovirus-mediated small interfering RNA (siRNA) to determine whether the use of Bach1 siRNA is an effective therapeutic strategy in mice with bleomycin (BLM)‑induced PF. Mouse lung fibroblasts (MLFs) were incubated with transforming growth factor (TGF)-β1 (5 ng/ml) and subsequently infected with recombined adenovirus-like Bach1 siRNA1 and Bach1 siRNA2, while an empty adenovirus vector was used as the negative control. The selected Bach1 siRNA with higher interference efficiency was used for the animal experiments. A mouse model of BLM-induced PF was established, and Bach1 siRNA (1x109 pfu) was administered to the mice via the tail vein. The results revealed that the Bach1 mRNA and protein levels were significantly downregulated by Bach1 siRNA. Furthermore, the MLFs infected with Bach1 siRNA exhibited increased mRNA and protein expression levels of heme oxygenase-1 and glutathione peroxidase 1, but decreased levels of TGF-β1 and interleukin-6 in the cell supernatants compared with the cells exposed to TGF-β1 alone. Bach1 knockdown by siRNA also enhanced the expression of antioxidant factors, but suppressed that of fibrosis‑related cytokines in mice compared with the BLM group. Finally, the inflammatory infiltration of alveolar and interstitial cells and the destruction of lung structure were significantly attenuated in the mide administered Bach1 siRNA compared with those in the BLM group. On the whole, our findings demonstrate that Bach1 siRNA exerts protective effects against BLM-induced PF in mice. Our data may provide the basis for the development of novel targeted therapeutic strategies for PF.

Plasma microRNAs are associated with acute exacerbation in idiopathic pulmonary fibrosis

BACKGROUND

Acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF) has high short-term mortality with unknown causes. To predict this malignant condition in clinics is challenging. In this study, we aim to demonstrate whether there are miRNAs that differ between AE-IPF and stable IPF, which may be served as reliable biomarker for AE-IPF prediction.

METHODS

Human fibrotic-associated miRNAs arrays were designed to detect miRNAs expression in plasma of 3 AE-IPF patients, 3 Stable-IPF (S-IPF) patients and 3 normal controls (NC). Differentially expressed miRNAs between AE-IPF and S-IPF patients were selected for further analyses. The validation studies were carried out in plasma of 12 AE-IPF patients, 45 S-IPF patients and 51 healthy control subjects. Signaling pathways and cellular processes interacted with validated miRNAs were predicted by DIANA-miRPath.

RESULTS

According to the array analysis, 6 miRNAs showed differentiated expression between AE-IPF and S-IPF patients (P < 0.05). In the validation studies, let-7d-5p was decreased in S-IPF and further decreased in AE-IPF, when compared to NC (0.0003 ± 0.0002 vs 0.003 ± 0.002, P < 0.01 and 0.0007 ± 0.0005 vs 0.003 ± 0.002, P < 0.01). While miR-25-3p was obviously decreased in S-IPF (0.0002 ± 0.0001 vs 0.0003 ± 0.0003, P < 0.01) but significantly increased in AE-IP (0.0023 ± 0.002 vs 0.0003 ± 0.0003, P < 0.01). In receiver-operator characteristic (ROC) curve analysis, the areas under the curve (AUCs) of miR-25-3p and let-7d-5p were 0.83 and 0.75, respectively. The sensitivity at fixed specificity of 90% was improved from 50% to 66.7% when the two miRNAs were combined. The functional prediction of miRNAs suggested that the loss of anti-fibrotic capacity and the gain of uncontrolled cell growth may be required in AE-IPF pathogenesis.

CONCLUSIONS

In conclusion, miR-25-3p and let-7d-5p in plasma were differentially expressed between AE-IPF and S-IPF. A combination of these two miRNAs may be a potential biomarker for AE-IPF from IPF.

Association between pulmonary fibrosis and osteoporosis in the elderly people: A case-control study

In this case-control study, we evaluated the association between osteoporosis and pulmonary fibrosis in the elderly. Participants were divided into a test group and a control group depending on bone mineral density and grid pattern changes of pulmonary fibrosis. We measured general conditions, related risk factors, serum biochemical index, grid pattern changes of double lungs, pulmonary function, arterial oxygen pressure (PO2), and bone mineral density of participates, and investigated the data through statistical analysis on SPSS 17.0 (SPSS Inc, Chicago, Illinois, USA). Significant differences were observed between groups in all collected indices except PO4. The ratio of pulmonary function disorder was higher in the test group versus the control group (12.0% vs 4.3%). Logistic regression shows that pulmonary fibrosis is a risk factor of osteoporosis, independent of age, sex, body mass index, smoking status, diabetes mellitus, alkaline phosphatase, glycosylated hemoglobin, Ca, PO4, tumor necrosis factor-α, vitamin D total, ventilation disorder, diffusive dysfunction, and hypoxemia. Senile osteoporosis is closely associated with pulmonary fibrosis, diabetes mellitus, smoking, sexuality, age, and body mass index. Pulmonary fibrosis modestly affects the incidence of osteoporosis and thus is a more promising predictor of osteoporosis.

Angiopoietin-2 expression in patients with an acute exacerbation of idiopathic interstitial pneumonias

BACKGROUND AND OBJECTIVE

We hypothesized that increased pulmonary vascular permeability may play a role in the pathogenesis of an acute exacerbation of the idiopathic interstitial pneumonias (AE-IIPs). Angiopoietin-2 (Ang-2) promotes endothelial activation, destabilization, and inflammation. The purpose of this study was to examine whether Ang-2 expression was associated with the pathogenesis of AE-IIPs.

METHODS

Twenty-three patients with AE-IIP patients, 18 acute lung injury/acute respiratory distress syndrome (ALI/ARDS) patients, 37 idiopathic pulmonary fibrosis (IPF) patients, and 33 healthy volunteers (HVs) were enrolled. The serum level of Ang-2 was measured by an enzyme-linked immunosorbent assay.

RESULTS

The serum levels of Ang-2 were higher in AE-IIPs and ALI/ARDS patients than in IPF patients and HVs; the BALF levels of Ang-2 were also higher than in IPF patients. There was a positive correlation between the serum level of Ang-2 and the CRP in patients with AE-IIP patients, whereas a significant positive correlation was found between the serum Ang-2 level and the CRP or SOFA scores of the ALI/ARDS patients. Although the baseline Ang-2 level was not related to survival, the Ang-2 levels significantly declined in survivors during treatment, while they did not change in non-survivors.

CONCLUSIONS

Increased pulmonary vascular permeability and inflammation due to Ang-2 may play a role in the pathogenesis of AE-IIPs.