Surface engineering of pure magnesium in medical implant applications.

This review comprehensively surveys the latest advancements in surface modification of pure magnesium (Mg) in recent years, with a focus on various cost-effective procedures, comparative analyses, and assessments of outcomes, addressing the merits and drawbacks of pure Mg and its alloys. Diverse economically feasible methods for surface modification, such as hydrothermal processes and ultrasonic micro-arc oxidation (UMAO), are discussed, emphasizing their exceptional performance in enhancing surface properties. The attention is directed towards the biocompatibility and corrosion resistance of pure Mg, underscoring the remarkable efficacy of techniques such as Ca-deficientca-deficient hydroxyapatite (CDHA)/MgF2 bi-layer coating and UMAO coating in electrochemical processes. These methods open up novel avenues for the application of pure Mg in medical implants. Emphasis is placed on the significance of adhering to the principles of reinforcing the foundation and addressing the source. The advocacy is for a judicious approach to corrosion protection on high-purity Mg surfaces, aiming to optimize the overall mechanical performance. Lastly, a call is made for future in-depth investigations into areas such as composite coatings and the biodegradation mechanisms of pure Mg surfaces, aiming to propel the field towards more sustainable and innovative developments.

PM2.5 induces lung inflammation and fibrosis via airway smooth muscle cell expression of the Wnt5a/JNK pathway.

Background: In recent years, particulate matter 2.5 (PM2.5) exposure has been considered a key dangerous factor in chronic obstructive pulmonary disease (COPD). The dysfunction of airway smooth muscle cells (ASMCs) facilitates lung inflammation and fibrosis in COPD. Therefore, we explored whether PM2.5 could promote the inflammatory response and fibrosis in ASMCs in vivo and in vitro via the wingless-related integration site 5a (Wnt5a)/c-Jun N-terminal kinase (JNK)/nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway. Methods: Wnt5a expression in the bronchoalveolar lavage fluid (BALF) of COPD patients exposed to PM2.5 was measured by enzyme-linked immunosorbent assay (ELISA). Mice were intratracheally injected with PM2.5 and a Wnt5a antagonist (BOX5). ASMCs were transfected with Wnt5a small interfering RNA (siRNA), BOX5 and the JNK inhibitor SP600125 before PM2.5 stimulation. Hematoxylin and eosin (H&E) staining was performed to measure the inflammatory response and airway fibrosis. The production of Wnt5a/JNK/NF-KB pathway factors was analyzed by Western blotting. The secretion of interleukin-6 (IL-6), IL-8 and tumor necrosis factor-α (TNF-α) was measured by ELISA. The expression levels of alpha smooth muscle actin (α-SMA), collagen I and collagen III were assessed by quantitative real time polymerase chain reaction (qRT-PCR) and Western blotting. Results: We found that the increase in Wnt5a expression in the BALF of COPD patients was positively correlated with the levels of PM2.5 exposure. The Wnt5a/JNK/NF-κB pathway was activated in the lung samples of PM2.5-induced model mice and PM2.5-exposed ASMCs, which promoted the production of α-SMA, collagen I and collagen III and increased the secretion of IL-6, IL-8 and TNF-α. Furthermore, our results showed that BOX5 could prevent these effects. Wnt5a siRNA blocked the activation of the Wnt5a/JNK/NF-κB pathway and inhibited the effects of PM2.5 on fibrosis and inflammation in ASMCs. SP600125 blocked the phosphorylation of NF-κB and inhibited inflammation and fibrosis in PM2.5-exposed ASMCs. Conclusions: These findings suggest that PM2.5 stimulation of ASMCs induces pulmonary inflammatory factor expression and collagen deposition during COPD via the Wnt5a/JNK pathway, which indicates that modulating the Wnt5a/JNK pathway could be a promising therapeutic strategy for PM2.5-induced COPD.

Association of mild chronic obstructive pulmonary disease with all-cause mortality: A systematic review and meta-analysis.

BACKGROUND: It is unclear whether patients with Global Initiative for Chronic Obstructive Lung Disease stage 1 (mild) chronic obstructive pulmonary disease (COPD) have worse respiratory outcomes than individuals with normal spirometry. METHODS: For this systematic review and meta-analysis, we conducted a search of PubMed, Embase, and Web of Science for all literature published up to 1 March 2023. Studies comparing mortality between mild COPD and normal spirometry were included. A random-effects model was used to estimate the combined effect size and its 95% confidence interval (CI). The primary outcome was all-cause mortality. Respiratory disease-related mortality were examined as secondary outcomes. RESULTS: Of 5242 titles identified, 12 publications were included. Patients with mild COPD had a higher risk of all-cause mortality than individuals with normal spirometry (pre-bronchodilator: hazard ratio [HR] = 1.21, 95% CI: 1.11-1.32, I2 = 47.1%; post-bronchodilator: HR = 1.19, 95% CI: 1.02-1.39, I2 = 0.0%). Funnel plots showed a symmetrical distribution of studies and did not suggest publication bias. In jackknife sensitivity analyses, the increased risk of all-cause mortality remained consistent for mild COPD. When the meta-analysis was repeated and one study was omitted each time, the HR and corresponding 95% CI were >1. Patients with mild COPD also had a higher risk of respiratory disease-related mortality (HR = 1.71, 95% CI: 1.03-2.82, I2 = 0.0%). CONCLUSIONS: Our results suggest that mild COPD is associated with increased all-cause mortality and respiratory disease-related mortality compared with normal spirometry. Further research is required to determine whether early intervention and treatment are beneficial in mild COPD.

Manta Ray Inspired Soft Robot Fish with Tough Hydrogels as Structural Elements.

The design of soft robots capable of navigation underwater has received tremendous research interest due to the robots' versatile applications in marine explorations. Inspired by marine animals such as jellyfish, scientists have developed various soft robotic fishes by using elastomers as the major material. However, elastomers have a hydrophobic network without embedded water, which is different from the gel-state body of the prototypes and results in high contrast to the surrounding environment and thus poor acoustic stealth. Here, we demonstrate a manta ray-inspired soft robot fish with tailored swimming motions by using tough and stiff hydrogels as the structural elements, as well as a dielectric elastomer as the actuating unit. The switching between actuated and relaxed states of this unit under wired power leads to the flapping of the pectoral fins and swimming of the gel fish. This robot fish has good stability and swims with a fast speed (∼10 cm/s) in freshwater and seawater over a wide temperature range (4-50 °C). The high water content (i.e., ∼70 wt %) of the robot fish affords good optical and acoustic stealth properties under water. The excellent mechanical properties of the gels also enable easy integration of other functional units/systems with the robot fish. As proof-of-concept examples, a temperature sensing system and a soft gripper are assembled, allowing the robot fish to monitor the local temperature, raise warning signals by lighting, and grab and transport an object on demand. Such a robot fish should find applications in environmental detection and execution tasks under water. This work should also be informative for the design of other soft actuators and robots with tough hydrogels as the building blocks.

GATA3/long noncoding RNA MHC-R regulates the immune activity of dendritic cells in chronic obstructive pulmonary disease induced by air pollution particulate matter.

Chronic obstructive pulmonary disease (COPD) is a heterogeneous illness associated with aberrant inflammatory immune reaction in the lung in response to noxious particles and gases. Our previous epidemiological studies discovered that long-term exposure to air pollution PM was associated with an increase in the incidence of COPD and lung function decline, but the impact of air pollution on the onset of COPD and its pathogenesis remains obscure. In recent years, long noncoding RNAs (lncRNAs) have been documented to have a crucial role in COPD. Our preliminary study found that the expression of lncRNA MHC-R in the lung tissues of rats exposed to air pollution PM was dramatically elevated, and the specific expression was mainly focused on the immune-related MHC I, antigen-presenting, and adaptive immune response. After transcription factor prediction, it was found that GATA3 could be combined with the specific sequence of the lncRNA MHC-R promoter region. Dendritic cells (DCs) are necessary antigen-presenting cells (APCs) with the most potent antigen-presenting function. We proved that GATA3/lncRNA MHC-R might regulate the immune activities of DCs to participate in the pathogenic mechanism of COPD induced by air pollution PM, which opens up a new way for early COPD diagnosis and treatment.

PM2.5 Induces Airway Remodeling in Chronic Obstructive Pulmonary Diseases via the Wnt5a/ß-Catenin Pathway.

BACKGROUND: Fine-particulate matter ≤2.5 µm in diameter (PM2.5)-associated airway remodeling has recently been recognized as a central feature of COPD. Activation of the Wnt/ß-catenin pathway is closely related to the occurrence of airway remodeling. Accordingly, the goal of this study was to determine whether the Wnt5a/ß-Catenin pathway is involved in PM2.5-induced smooth muscle proliferation in vivo and in vitro, which promotes the development of airway remodeling in subjects with COPD. METHODS: The effect of Wnt5a on ß-Catenin-mediated airway remodeling was assessed using an in vivo model of PM2.5-induced COPD and PM2.5-exposed human bronchial smooth muscle cells (HBSMCs) in vitro. Small animal spirometry was used to measure lung function in mice. H&E staining and immunohistochemistry were performed to inspect emphysema and airway remodeling indices. Real-time PCR was used to detect Wnt5a, ß-Catenin, TGF-ß1, CyclinD1 and c-myc mRNA expression. The CCK8 assay was performed to detect cellular activity. Western blotting was performed to assess PCNA, α-SMA, Wnt5a, ß-Catenin, PDGFRß and TenascinC protein expression. ß-Catenin expression was detected using cellular immunofluorescence. RESULTS: Exposure to PM2.5 led to emphysema, airway wall thickening, an increased smooth muscle layer thickness, decreased lung function and increased expression of the Wnt5a, ß-Catenin, PDGFRß and Tenascin C proteins in the mouse lung tissue. BOX5 (a Wnt5a antagonist) alleviated these PM2.5-induced outcomes in mice. Moreover, PM2.5 induced the expression of the Wnt5a, ß-Catenin, TGF-ß1, CyclinD1 and c-myc mRNAs in HBSMCs. BOX5 also inhibited the PM2.5-induced increases in PCNA, α-SMA, Wnt5a, ß-Catenin, PDGFRß and Tenascin C protein expression in HBSMCs. CONCLUSION: Our findings suggest that PM2.5 exposure induces HBSMC proliferation, contributing to airway remodeling via the Wnt5a/ß-Catenin signaling pathway in vivo and in vitro, which might be a target for COPD treatment.

GSK-3ß Inhibitors Attenuate the PM2.5-Induced Inflammatory Response in Bronchial Epithelial Cells.

BACKGROUND AND PURPOSE: PM2.5-associated airway inflammation has recently been recognized as pivotal to the development of COPD. Aberrant glycogen synthase kinase (GSK)-3ß signaling is linked to the inflammatory response. Therefore, we investigated the effects of GSK-3ß inhibitors on the PM2.5-induced inflammatory response in bronchial epithelial cells. METHODS: The production of phosphorylated GSK-3ß (p-GSK-3ß) was analyzed by immunohistochemistry with PM2.5-induced mice. HBECs were treated with various inhibitors targeting GSK-3ß or JNK before PM2.5 stimulation. The production of GSK-3ß signaling was analyzed by Western blotting. Inflammatory cytokine production was detected by qRT-PCR and ELISA. RESULTS: PM2.5 exposure caused lung inflammation, upregulated serum concentrations of HMGB1 and IL-6, decreased IL-10 expression, and significantly attenuated p-GSK-3ß production in mice. HBECs exposed to PM2.5 showed significantly reduced p-GSK-3ß production, an increased ratio of p-JNK/JNK, increased NF-κB activation and IκB degradation, and upregulated the inflammatory cytokines HMGB1 and IL-6. Intervention with GSK-3ß inhibitors TDZD-8 and SB216763 significantly suppressed PM2.5-induced outcomes. Moreover, the JNK inhibitor SP600125 also reduced the level of NF-κB phosphorylation induced by PM2.5. The differences in the levels of inflammation-related cytokines in the TDZD-8 groups were greater than those in the SB216763 groups. CONCLUSION: Inhibition of GSK-3ß weakens the PM2.5-induced inflammatory response by regulating the JNK/NF-κB signaling pathway in bronchial epithelial cells.

Prevalence and characteristics of chronic obstructive pulmonary disease in China with a diagnostic criterion of FEV1/FVC less than the lower limit of normal-a reanalysis of Chinese epidemiological survey of COPD (CESCOPD) study.

Background: To reappraise the prevalence and characteristics of chronic obstructive pulmonary disease (COPD) in China with a criterion of FEV1/FVC < the lower limit of normal (LLN). Methods: We assessed the incidence and characteristics of airflow limitation using data from the Chinese Epidemiological Survey of COPD study-a multicenter, randomized trial, with an age-dependent LLN reference equation [established by the Guangzhou Institute of Respiratory Health (GIRH)]. Questionnaire and spirometry data were collected for all eligible subjects. COPD prevalence, risk factors, severity distribution, as well as comparisons of characteristics between the LLN and 0.7 were analyzed. Results: COPD prevalence was 9.0% among participants aged 40-80 years in China with the criterion of LLN. Greater prevalence was observed in female sex, rural areas and never smokers than with the GOLD 0.7 fixed ratio. Age distribution showed a higher incidence of COPD in people under 60 years but lower in participants over 60 years of age. With the LLN FEV1 reference equation, patients in stage I were decreased (15.8% vs. 24.6%, P<0.001), while the proportion of patients in stage III and IV were increased when compared with the China 2002 revised equation (27.7% vs. 21.1%, for stage III, P<0.001; 8.7% vs. 5.6% for stage IV, P=0.001). Only 30.8% of patients with COPD had ever been "diagnosed" with COPD and 60.6% of the patients had respiratory symptoms, both lower than that under the GOLD 0.7 fixed-ratio criterion (35.5%, P=0.004; 64.8% for symptoms, P=0.014). Conclusions: With the GIRH-LLN criterion, COPD prevalence was slightly higher, and a large number of women, rural patients and nonsmokers with young age and little symptoms were diagnosed when compared with GOLD 0.7 fixed ratio. These subjects may, therefore, deserve further attention and may warrant regular follow-up. Trial Registration: Registration number: ChiCTR-ECS-13004110.

Changes in the gut microbiome and metabolome in a rat model of pulmonary arterial hypertension.

The gut microbiota is widely considered to be involved in several diseases, including atherosclerosis, obesity, chronic obstructive pulmonary disease (COPD) and pulmonary arterial hypertension (PAH). This study aimed to determine if changes in the gut microbiome and metabolome play a major role in the early pathogenesis of PAH. Male Wistar rats were injected with monocrotaline (MCT) (55 mg/kg) at day 1 and injected with calcium-sensing receptor (CaSR) antagonist NPS2143 (4.5 mg/kg/d) from days 1 to 21. Fecal samples were obtained. The gut microbiota and metabolome were analyzed by 16S rRNA gene sequencing and mass spectrometry-based analysis to investigate the effect of PAH in this rat model. MCT injection had a marked effect on the composition of the gut microbiota. This finding was further confirmed by metabolomic analysis with identification of several metabolites relevant to the gut microflora. However, NPS2143 partially abrogated this intestinal flora disorder and reversed fecal metabolite abnormalities. In conclusion, our study shows correlations between changes in the gut microbiome and the metabolome in PAH, which are affected by NPS2143.

Design and Performance Study for Electrothermally Deep-Sea Drive Microunits Using a Paraffin Phase Change Material.

Considering the further exploration of the ocean, the requirements for deep-sea operation equipment have increased. Many problems existing in the widely used deep-sea hydraulic system have become increasingly prominent. Compared with the traditional deep-sea hydraulic system, actuators using a paraffin phase change material (PCM) have incomparable advantages, including lightweight structure, low energy consumption, high adaptability to the deep sea, and good biocompatibility. Thus, a deep-sea drive microunit (DDM) based on paraffin PCM is proposed in this paper. The device adopts a flexible shell, adapting to the high-pressure environment of the deep-sea based on the principle of pressure compensation. The device realizes the output of displacement and force through the electrothermal drive, which can be used as actuator or power source of other underwater operation equipment. The microunit successfully completes the functional verification experiments in air, shallow water, and hydrostatic pressure of 110 MPa. In accordance with experimental results, a reasonable control curve is fitted, highlighting its potential application in deep-sea micro electro mechanical systems, especially in underwater soft robot.

Self-powered soft robot in the Mariana Trench.

The deep sea remains the largest unknown territory on Earth because it is so difficult to explore1-4. Owing to the extremely high pressure in the deep sea, rigid vessels5-7 and pressure-compensation systems8-10 are typically required to protect mechatronic systems. However, deep-sea creatures that lack bulky or heavy pressure-tolerant systems can thrive at extreme depths11-17. Here, inspired by the structure of a deep-sea snailfish15, we develop an untethered soft robot for deep-sea exploration, with onboard power, control and actuation protected from pressure by integrating electronics in a silicone matrix. This self-powered robot eliminates the requirement for any rigid vessel. To reduce shear stress at the interfaces between electronic components, we decentralize the electronics by increasing the distance between components or separating them from the printed circuit board. Careful design of the dielectric elastomer material used for the robot's flapping fins allowed the robot to be actuated successfully in a field test in the Mariana Trench down to a depth of 10,900 metres and to swim freely in the South China Sea at a depth of 3,224 metres. We validate the pressure resilience of the electronic components and soft actuators through systematic experiments and theoretical analyses. Our work highlights the potential of designing soft, lightweight devices for use in extreme conditions.

Development and Experiments of an Electrothermal Driven Deep-Sea Buoyancy Control Module.

Due to the extremely high pressures in the deep sea, heavy ballast tanks and pressure compensating hydraulic tanks are typically required to support the operation of classic buoyancy controls. Buoyancy control systems driven by phase-change materials (PCM) have unique advantages over conventional hydraulically actuated buoyancy control systems, including high adaptability for deep-sea exploration and simple, lightweight, and compact structures. Inspired by this, a buoyancy control module (BCM) was designed with flexible material as the shell. Instead of a conventional mechanical system, the device uses an electric heating drive to control buoyancy by heating and cooling the PCM. Based on the principle of pressure compensation, this device can adjust the buoyancy of a small underwater vehicle in a deep-sea high-pressure environment. The BCM successfully adjusts the buoyancy to lift itself up and down in the South China Sea at a depth of 3223 m. The performance of the phase-change BCM to control buoyancy under high pressure is validated by systematic experiments and theoretical analysis. Our work proposes a flexible scheme for the design of a deep-sea phase-change-driven BCM and highlights its potential application in deep-sea micro-mechanical systems, especially soft robots.

PM2.5 Induces the Expression of Inflammatory Cytokines via the Wnt5a/Ror2 Pathway in Human Bronchial Epithelial Cells.

Background and Purpose: Recently, fine particulate matter (PM2.5) was identified as the main exposure risk for COPD, and inflammation is central to the development of COPD. In this study, we investigated whether PM2.5 can induce the secretion of interleukin-6 (IL-6), IL-8 and IL-1ß in human bronchial epithelial cells (HBECs) in vitro via the wingless-related integration site 5A (Wnt5a)/receptor tyrosine kinase-like orphan receptor 2 (Ror2) signaling. Methods: The expression of Wnt5a and Ror2 was assessed by immunohistochemistry in motor vehicle exhaust (MVE)-induced Sprague-Dawley rats. HBECs were transfected with small interfering RNA (siRNA) targeting Wnt5a or Ror2 and subsequently stimulated with PM2.5.The secretion of IL-6, IL-8 and IL-1ß was assessed by ELISAs, and the expression of Wnt5a/Ror2 signaling were assessed by RT-PCR and Western blotting. Results: Both Wnt5a and Ror2 protein were increased in the lung of MVE-induced rats. HBECs exposed to PM2.5 for 24 h significantly upregulated Wnt5a and Ror2 expression and subsequently promoted the nuclear translocation of NF-κB, which increased the production of IL-1ß, IL-6 and IL-8. Wnt5a siRNA prevented these outcomes. Wnt5a antagonist (BOX5) also prevented inflammatory effects. Furthermore, Ror2 siRNA blocked the NF-κB activity and inhibited the release of IL-6, IL-8 and IL-1ß from PM2.5-exposed HBECs. Conclusion: PM2.5 induces the secretion of IL-6, IL-8 and IL-1ß in HBECs via the Wnt5a/Ror2 signaling, demonstrating a novel mechanism for PM2.5-associated airway inflammation.

Clinical impact of the lower limit of normal of FEV1/FVC on detecting chronic obstructive pulmonary disease: A follow-up study based on cross-sectional data.

BACKGROUND: Criteria of obstruction that establish a diagnosis of COPD have been debated in recent years. We carried out a follow-up study to assess the impact of the new LLN reference equation for Chinese on detecting COPD compared with the traditional 0.7fixed criteria. METHODS: We examined the prevalence and characteristics of airflow limitation for a non-child population using post-bronchodilator airflow with both age-dependent predicted lower limit of the normal value and fixed-ratio spirometric criterion. Questionnaires and spirometry were completed for all eligible subjects during the baseline examination. Participants with inconsistent diagnosis according to the two criteria, normal participants (controls) and COPD patients in stages I or II, were invited to take a cardiopulmonary exercise testing (CPET) examination and follow up for 2-4 years. RESULTS: A total of 5448 (mean age 50.51 ±â€¯13.2 yr) study subjects with acceptable spirometry and complete questionnaire data were included in our final analyses. COPD detection based on LLN was consistent with the GOLD 0.7 fixed-ratio in general, as 51 subjects (0.9%) were underdiagnosed, and 61 subjects (1.1%) were overdiagnosed when using LLN as the reference diagnostic criterion. The underdiagnosed subjects were younger, had more symptoms, more exposure to biofuels and worse FEV1 than the normal group; they also demonstrated a damaged cardiopulmonary reserve capacity and significant FEV1 decline. Except for being older, the overdiagnosed subjects differed little from the normal group. CONCLUSIONS: Individual-dependent LLN appears to better reveal impacts on detecting airflow limitation. Participants underdiagnosed by GOLD criterion should be paid more attention. CLINICAL TRIAL REGISTRATION: ChiCTR-ECS-13004110.

PM2.5 Induced the Expression of Fibrogenic Mediators via HMGB1-RAGE Signaling in Human Airway Epithelial Cells.

Background: The aim of the present study was to test whether fine particulate matter (PM2.5) induces the expression of platelet-derived growth factor-AB (PDGF-AB), PDGF-BB, and transforming growth factor-ß1 (TGF-ß1) in human bronchial epithelial cells (HBECs) in vitro via high-mobility group box 1 (HMGB1) receptor for advanced glycation end products (RAGE) signaling. Methods: Sprague-Dawley rats were exposed to motor vehicle exhaust (MVE) or clean air. HBECs were either transfected with a small interfering RNA (siRNA) targeting HMGB1 or incubated with anti-RAGE antibodies and subsequently stimulated with PM2.5. Results: The expression of HMGB1 and RAGE was elevated in MVE-treated rats compared with untreated rats, and PM2.5 increased the secretion of HMGB1 and upregulated RAGE expression and the translocation of nuclear factor κB (NF-κB) into the nucleus of HBECs. This activation was accompanied by an increase in the expression of PDGF-AB, PDGF-BB, and TGF-ß1. The HMGB1 siRNA prevented these effects. Anti-RAGE antibodies attenuated the activation of NF-κB and decreased the secretion of TGF-ß1, PDGF-AB, and PDGF-BB from HBECs. Conclusion: PM2.5 induces the expression of TGF-ß1, PDGF-AB, and PDGF-BB in vitro via HMGB1-RAGE signaling, suggesting that this pathway may contribute to the airway remodeling observed in patients with COPD.

Association between exposure to ambient particulate matter and chronic obstructive pulmonary disease: results from a cross-sectional study in China.

OBJECTIVE: The association between exposure to ambient particles with a median aerodynamic diameter less than 10/2.5 µm (particulate matter, PM10/2.5) and COPD remains unclear. Our study objective was to examine the association between ambient PM10/2.5 concentrations and lung functions in adults. METHODS: A cross-sectional study was conducted in southern China. Seven clusters were randomly selected from four cities across Guangdong province. Residents aged ≥20 years in the participating clusters were randomly recruited; all eligible participants were examined with a standardised questionnaire and spirometry. COPD was defined as a post-bronchodilator FEV1/FVC less than 70%. Atmosphere PM sampling was conducted across the clusters along with our survey. RESULTS: Of the subjects initially recruited, 84.4% (n=5993) were included for analysis. COPD prevalence and atmosphere PM concentration varied significantly among the seven clusters. COPD prevalence was significantly associated with elevated PM concentration levels: adjusted OR 2.416 (95% CI 1.417 to 4.118) for >35 and ≤75 µg/m3 and 2.530 (1.280 to 5.001) for >75 µg/m3 compared with the level of ≤35 µg/m3 for PM2.5; adjusted OR 2.442 (95% CI 1.449 to 4.117) for >50 and ≤150 µg/m3 compared with the level of ≤50 µg/m3 for PM1. A 10 µg/m3 increase in PM2.5 concentrations was associated with a 26 mL (95% CI -43 to -9) decrease in FEV1, a 28 mL (-49 to -8) decrease in FVC and a 0.09% decrease (-0.170 to -0.010) in FEV1/FVC ratio. The associations of COPD with PM10 were consistent with PM2.5 but slightly weaker. CONCLUSIONS: Exposure to higher PM concentrations was strongly associated with increased COPD prevalence and declined respiratory function. TRIAL REGISTRATION NUMBER: ChiCTR-OO-14004264; Post-results.

Nicotine reduces the levels of surfactant proteins A and D via Wnt/ß-catenin and PKC signaling in human airway epithelial cells.

A deficiency of surfactant proteins A and D has been proposed as a mechanism in airway remodeling, which is one characteristic of chronic obstructive pulmonary disease (COPD). We recently showed that in vitro nicotine exposure induces Wnt3a/ß-catenin activation, which is a pathway that has also been implicated in altering levels of SP-A and SP-D. Nicotine induced activation of protein kinase C(PKC), and the involvement of PKC in mediating Wnt signaling has been demonstrated previously. The main aim of this study was to investigate whether human bronchial epithelial cells reduce levels of SP-A and SP-D in vitro following nicotine stimulation via the Wnt3a/ß-catenin and PKC signaling pathway. We showed that nicotine activated the Wnt3a/ß-catenin and PKC signaling pathway, and this activation was accompanied by a decrease in SP-A and SP-D expression. Knockdown of Wnt3a with small interfering RNA (siRNA) prevented translocation of ß-catenin into the nucleus and reduction levels of SP-A and SP-D. Furthermore, a PKC inhibitor partially prevented these effects,which suggests in HBECs, Wnt3a/ß-catenin and PKC pathways interact during nicotine-reduced levels of SP-A and SP-D. These results suggest that HBECs reduce the levels of surfactant proteins A and D in vitro via the Wnt3a/ß-catenin and PKC signaling pathway upon nicotine stimulation.

Exon sequencing identifies a novel CHRNA3-CHRNA5-CHRNB4 variant that increases the risk for chronic obstructive pulmonary disease.

BACKGROUND AND OBJECTIVE: Recent genome-wide association studies have established that single nucleotide polymorphisms in the CHRNA3-CHRNA5-CHRNB4 genes are susceptibility loci for chronic obstructive pulmonary disease COPD. However, further effort is still required to reveal their genetic contribution to COPD, considering the existence of 'missing heritability', which may be mediated by variants that are of a low frequency or rare. Here we aimed to identify genetic variants in the coding regions of the CHRNA3-CHRNA5-CHRNB4 genes and determine their associations with COPD risk in Chinese. METHODS: We directly sequenced the coding regions of the CHRNA3-CHRNA5-CHRNB4 genes in 160 Chinese subjects, and then genotyped the missense or synonymous variants that have previously been reported to be associated with COPD risk in a two-stage case-control study involving 1013 COPD cases and 1030 controls of southern Chinese. RESULTS: We found nine variants, three of which were missense variations (Ser140Gly, His462Gln and Asp398Asn), while two were synonymous variants (Tyr215Tyr and Val53Val). The variants Ser140Gly, Tyr215Tyr and Asp398Asn were significantly associated with COPD risk. By combining these variants, the number of risk genotypes significantly increased the risk for COPD in a dose-dependent manner (Ptrend = 5.00 × 10(-4) ). The risk genotype number was also significantly correlated with several lung function parameters, including forced expiratory volume in 1 s (FEV1 ), FEV1 % predicted, FEV1 /forced vital capacity ratio and peak expiratory flow. CONCLUSIONS: The present study identified a novel exon variant Ser140Gly, and two previously reported variants Tyr215Tyr and Asp398Asn are significantly associated with COPD risk in Chinese. These variants may be genetic biomarkers for predicting COPD risk in Chinese. Validation in other ethnicities is warranted.

Upregulation of gelatinases and epithelial-mesenchymal transition in small airway remodeling associated with chronic exposure to wood smoke.

BACKGROUND: Peribronchiolar fibrosis is an important feature of small airway remodeling (SAR) in cigarette smoke-induced COPD. The aim of this study was to investigate the role of gelatinases (MMP9, MMP2) and epithelial-mesenchymal transition (EMT) in SAR related to wood smoke (WS) exposure in a rat model. METHODS: Forty-eight female Sprague-Dawley rats were randomly divided into the WS group, the cigarette smoke (CS) group and the clean air control group. After 4 to 7 months of smoke exposure, lung tissues were examined with morphometric measurements, immunohistochemistry and Western blotting. Serum MMP9 and TIMP1 concentrations were detected by ELISA. In vitro, primary rat tracheal epithelial cells were stimulated with wood smoke condensate for 7 days. RESULTS: The COPD-like pathological alterations in rats exposed chronically to WS were similar to those exposed to CS; the area of collagen deposition was significantly increased in the small airway walls of those exposed to WS or CS for 7 months. The expression of gelatinases in rats induced by WS or CS exposure was markedly increased in whole lung tissue, and immunohistochemistry showed that MMP9, MMP2 and TIMP1 were primarily expressed in the airway epithelium. The serum levels of MMP9 and TIMP1 were significantly higher in rats secondary to WS or CS exposure. Few cells that double immunostained for E-cadherin and vimentin were observed in the airway subepithelium of rats exposed to WS for 7 months (only 3 of these 8 rats). In vitro, the expression of MMP9 and MMP2 proteins was upregulated in primary rat tracheal epithelial cells following exposure to wood smoke condensate for 7 days by Western blotting; positive immunofluorescent staining for vimentin and type I collagen was also observed. CONCLUSIONS: These findings suggest that the upregulation of gelatinases and EMT might play a role in SAR in COPD associated with chronic exposure to wood smoke.

[Wood smoke condensate induced epithelial-mesenchymal transition in human airway epithelial cells].

OBJECTIVE: To observe the detrimental effects of wood smoke condensate (WSC) exposure on human bronchial epithelial cells (HBEC), and to explore the expression of epithelial-mesenchymal transition (EMT) markers in HBEC exposed to WSC. METHODS: HBEC were exposed respectively to 5, 10, 20, 40 and 50 mg/L of WSC /CSC for 7 days, with control groups only in cell culture medium at the same time, then the total cytoactivity was detected by cell counting kit-8. After observing the cellular morphology of WSC-stimulated HBEC. Western blot and immunofluorescence method were used to evaluate the expression levels of type I collagen, vimentin, E-cad and MMP-9 in HBEC exposed to WSC (10 mg/L) and cigarette smoke condensate (CSC) (10 mg/L) for 7 days. Statistical evaluation of the continuous data was performed by ANOVA. Independent-Samples t-test for between-group comparisons. RESULTS: After 7 days of exposure to WSC, HBEC manifested a morphological characteristic of loss of cell-cell contact and elongated shape. The level of E-cad was decreased in WSC exposure groups (Western blot: 0.30 ± 0.05, F = 22.07, P < 0.05) compared with the groups without WSC exposure (Western blot: 0.59 ± 0.08, F = 22.07, P < 0.05). In contrast, an upregulation in expression of type I collagen (Western blot: 0.58 ± 0.04 vs 0.26 ± 0.02, F = 119.72, P < 0.05) and MMP-9 (0.56 ± 0.08 vs 0.19 ± 0.03, F = 21.79, P < 0.05) was observed in the presence of WSC, compared with the control groups. Immunofluorescence analysis showed that after a 7-day exposure to WSC in these cells, the E-cad protein was lost whereas type I collagen, vimentin and MMP-9 were acquired. Both Western blot and immunofluorescence analysis showed no difference in expression levels of E-cad, type I collagen, vimentin and MMP-9 between WSC and CSC exposure groups. CONCLUSION: WSC exposure could induce EMT-like process in human airway epithelial cells.