Linear Intercept Research Articles

INOS Deletion in Alveolar Epithelium Cannot Reverse the Elastase-Induced Emphysema in Mice.

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide. In addition to chronic bronchitis and emphysema, patients often develop at least mild pulmonary hypertension (PH). We previously demonstrated that inhibition of inducible nitric oxide synthase (iNOS) prevents and reverses emphysema and PH in mice. Interestingly, strong iNOS upregulation was found in alveolar epithelial type II cells (AECII) in emphysematous murine lungs, and peroxynitrite, which can be formed from iNOS-derived NO, was shown to induce AECII apoptosis in vitro. However, the specific cell type(s) that drive(s) iNOS-dependent lung regeneration in emphysema/PH has (have) not been identified yet. we tested whether iNOS knockout in AECII affects established elastase-induced emphysema in mice. four weeks after a single intratracheal instillation of porcine pancreatic elastase for the induction of emphysema and PH, we induced iNOS knockout in AECII in mice, and gave an additional twelve weeks for the potential recovery. iNOS knockout in AECII did not reduce elastase-induced functional and structural lung changes such as increased lung compliance, decreased mean linear intercept and increased airspace, decreased right ventricular function, increased right ventricular systolic pressure and increased pulmonary vascular muscularization. In vitro, iNOS inhibition did not reduce apoptosis of AECII following exposure to a noxious stimulus. taken together, our data demonstrate that iNOS deletion in AECII is not sufficient for the regeneration of emphysematous murine lungs, and suggest that iNOS expression in pulmonary vascular or stromal cells might be critically important in this regard.

Nebulization of risedronate alleviates airway obstruction and inflammation of chronic obstructive pulmonary diseases via suppressing prenylation-dependent RAS/ERK/NF-κB and RhoA/ROCK1/MLCP signaling

BackgroundChronic obstructive pulmonary disease (COPD) is a progressive disorder that causes airway obstruction and lung inflammation. The first-line treatment of COPD is the bronchodilators of β2-agonists and antimuscarinic drugs, which can help control the airway obstruction, but the long-term use might render the drug tolerance. Bisphosphonates are widely used in osteoclast-mediated bone diseases treatment for decades. For drug repurposing, can delivery of a third generation of nitrogen-containing bisphosphonate, risedronate (RIS) ameliorate the progression of COPD?MethodsCOPD rats or mice models have been established through cigarette-smoking and elastase injection, and then the animals are received RIS treatment via nebulization. Lung deposition of RIS was primarily assessed by high-performance liquid chromatography (HPLC). The respiratory parameters of airway obstruction in COPD rats and mice were documented using plethysmography method and resistance-compliance system.ResultsHigh lung deposition and bioavailability of RIS was monitored with 88.8% of RIS input dose. We found that RIS could rescue the lung function decline of airspace enlargement and mean linear intercept in the COPD lung. RIS could curb the airway obstruction by suppressing 60% of the respiratory resistance and elevating the airway’s dynamic compliance, tidal volume and mid-expiratory flow. As an inhibitor of farnesyl diphosphate synthase (FDPS), RIS suppresses FDPS-mediated RAS and RhoA prenylation to obstruct its membrane localization in airway smooth muscle cells (ASMCs), leading to the inhibition of downstream ERK-MLCK and ROCK1-MLCP pathway to cause ASMCs relaxation. Additionally, RIS nebulization impeded pro-inflammatory cell accumulation, particularly macrophages infiltration in alveolar parenchyma. The NF-κB, tumor necrosis factor-alpha, IL-1β, IL-8, and IL-6 declined in microphages following RIS nebulization. Surprisingly, nebulization of RIS could overcome the tolerance of β2-agonists in COPD-rats by increasing the expression of β2 receptors.ConclusionsNebulization of RIS could alleviate airway obstruction and lung inflammation in COPD, providing a novel strategy for treating COPD patients, even those with β2-agonists tolerance.

Prolonged smoldering Douglas fir smoke inhalation augments respiratory resistances, stiffens the aorta, and curbs ejection fraction in hypercholesterolemic mice

While mounting evidence suggests that wildland fire smoke (WFS) inhalation may increase the burden of cardiopulmonary disease, the occupational risk of repeated exposure during wildland firefighting remains unknown. To address this concern, we evaluated the cardiopulmonary function in mice following a cumulative exposure to lab-scale WFS equivalent to a mid-length wildland firefighter (WLFF) career. Dosimetry analysis indicated that 80 exposure hours at a particulate concentration of 22 mg/m3 yield in mice the same cumulative deposited mass per unit of lung surface area as 3600 h of wildland firefighting. To satisfy this condition, male Apoe−/− mice were whole-body exposed to either air or smoldering Douglas fir smoke (DFS) for 2 h/day, 5 days/week, over 8 consecutive weeks. Particulate size in DFS fell within the respirable range for both mice and humans, with a count median diameter of 110 ± 20 nm. Expiratory breath hold in mice exposed to DFS significantly reduced their minute volume (DFS: 27 ± 4; Air: 122 ± 8 mL/min). By the end of the exposure time frame, mice in the DFS group exhibited a thicker (DFS: 109 ± 3; Air: 98 ± 3 μm) and less distensible (DFS: 23 ± 1; Air: 28 ± 1 MPa−1) aorta with reduced diastolic blood augmentation capacity (DFS: 53 ± 2; Air: 63 ± 2 kPa). Cardiac magnetic resonance imaging further revealed larger end-systolic volume (DFS: 14.6 ± 1.1; Air: 9.9 ± 0.9 μL) and reduced ejection-fraction (DFS: 64.7 ± 1.0; Air: 75.3 ± 0.9 %) in mice exposed to DFS. Consistent with increased airway epithelium thickness (DFS: 10.4 ± 0.8; Air: 7.6 ± 0.3 μm), airway Newtonian resistance was larger following DFS exposure (DFS: 0.23 ± 0.03; Air: 0.20 ± 0.03 cmH2O-s/mL). Furthermore, parenchyma mean linear intercept (DFS: 36.3 ± 0.8; Air: 33.3 ± 0.8 μm) and tissue thickness (DFS: 10.1 ± 0.5; Air: 7.4 ± 0.7 μm) were larger in DFS mice. Collectively, mice exposed to DFS manifested early signs of cardiopulmonary dysfunction aligned with self-reported events in mid-career WLFFs.

Analysis of grain size distribution evolution of steel during recrystallization and grain growth

Controlling the hot rolling process requires a deep understanding of the underlying metallurgical phenomena. Quantitative methods are of paramount importance for achieving the capability of controlling microstructural evolution. Since the final mechanical properties of steel result from microstructural evolution in the whole process, analysis of the microstructure provides an important input for numerical simulations that can be used for tailoring the mechanical properties of steel. The evolution of grain size distribution of a low-carbon CrNiMnB ultrahigh-steel in austenitic state is studied in hot forming and annealing using experimental data obtained with the Gleeble 3800 thermo-mechanical simulator. A general method is described that can be utilized to systematically compare the grain size distributions obtained from the experimental studies. The experimental data has been obtained from laser scanning confocal microscopy images using the mean linear intercept method. A custom-made semi-automatic software has been utilized to process the data rapidly and reliably.

Preterm rabbit-derived Precision Cut Lung Slices as alternative model of bronchopulmonary dysplasia in preclinical study: a morphological fine-tuning approach

Bronchopulmonary dysplasia (BPD) is the most common complication of preterm delivery, with significant morbidity and mortality in a neonatal intensive care setting. Research in this field aims to identify the mechanisms of late lung development with possible therapeutic targets and the improvement of medical management. Rabbits represent a suitable lab preclinical tool for mimicking the clinical BPD phenotype. Rabbits are born at term in the alveolar phase as occurs in large animals and humans and in addition, they can be delivered prematurely in contrast to mice and rats. Continuous exposure to high oxygen concentration (95% O2) for 7 days induces functional and morphological lung changes in preterm rabbits that resemble those observed in BPD-affected babies. The preclinical research pays great attention to optimize the experimental procedures, reduce the number of animals used in experiments and, where possible, replace animal models with alternative assays, following the principle of the 3 Rs (Replace, Reduce and Refine). The use of in vitro assays based on the ex vivo culture of Precision Cut Lung Slices (PCLS) goes in this direction, representing a good compromise between controlled and flexible in vitro models and the more physiologically relevant in vivo ones. This work aims to set up morphological analyses to be applied in preclinical tests using preterm rabbits derived PCLS, cultured up to 7 days in different oxygen conditions, as a model. After a preliminary optimization of both lung preparation and histological processing methods of the lung slices of 300 µm, the morphological analysis was conducted evaluating a series of histomorphometric parameters derived from those widely used to follow the phases of lung development and its alterations in vivo. Our histomorphometric results demonstrated that the greatest differences from pseudo-normoxia and hyperoxia exposed samples at day 0, used as starting points to compare changes due to treatments and time, are detectable after 4 days of in vitro culture, representing the most suitable time point for analysis in preclinical screening. The combination of parameters suitable for evaluating PCLS morphology in vitro resulted to be Tissue Density and Septal Thickness. Shape Factor and Roughness, evaluated to highlight the increasing complexity of the airspaces, due to the formation of septal crests, gave useful information, however, without significant differences up to day 4. Other parameters like Mean Linear Intercept and Septal Density did not allow to highlight significant differences between different oxygen conditions and time points. Instead, Radial Alveolar Count, could not be applied to PCLS, due to the tissue changes following agar infusion and culture conditions.

Size dependent allocation to vegetative and reproductive organs of the orchid <i>Lankesterella ceracifolia</i> (Spiranthinae)

How functional organ traits vary with increasing plant size reveals the strategies of plants to acquire, store and utilize resources that ensure vegetative growth and reproduction. Plant size can influence fitness; thus, the relationships of organ traits should be evaluated together with reproductive allocation, but this is rarely the case. The relationship among plant size, functional organ traits (number and size of roots, leaves and flowers, and scape size), and dry mass partitioning was analyzed intraspecifically using 35 reproductive individuals of the epiphytic orchid Lankesterella ceracifolia. The relationships between vegetative and reproductive organ traits were evaluated using different regression models. Size-dependent allocation to reproduction was evaluated through reproductive versus vegetative (RV) regressions for the entire inflorescence and separately for scape and flowers. The four regression models included simple (slope only), linear (slope and intercept), allometric (without intercept), and non-linear (allometric with intercept), were fitted to RV and compared via a log likelihood-ratio test. Preferential allocation to leaves instead of roots influenced how rosette frontal area changed with increasing plant size. Flower dry mass represented 70% of the inflorescence dry mass, an unusual result as scape dry mass generally represents most of the reproductive structure in plants. The allometric model was suitable for the entire inflorescence or only the scape, while the isometric model was best for flowers. Dry mass investment in the scape influenced the final reproductive allometry found for the orchid L. ceracifolia.

Abstract 12012: Subphenotypes of Heart Failure With Reduced Ejection Fraction Based on Repeated Measurements of 4210 Circulating Proteins Are Driven by Protein Subsets Reflecting Different Biological Mechanisms

Introduction: Subphenotyping of HF may lead to pathophysiological insights and treatment opportunities. We aimed to identify novel circulating-protein based subphenotypes (SP) in patients with HFrEF. We used repeated proteomic assessments to account for the dynamic nature of HF. Methods: In 382 patients, we performed trimonthly blood sampling during a median follow-up of 2.1 years. We selected all baseline samples and two samples closest to the primary endpoint (PEP; composite of cardiovascular mortality, HF hospitalization, LVAD implantation, and heart transplantation) or censoring and applied an aptamer-based multiplex proteomic approach. We used unsupervised machine learning to derive subphenotypes from 4210 protein trajectories per patient represented by linear mixed effect intercept and slope coefficients. Results: We identified 4 SPs. SP1 was older with higher SBP, EF and history of hypertension. SP2 was older with lower SBP, lower EF, more comorbidities, and worse prognosis (adjHR(95% CI): 4.06 (2.07-7.96)) compared to SP1. SP3 was younger, had lower SBP and EF, more frequently cardiomyopathy (in particular dilated), and a worse prognosis (2.70 (1.33-5.48)). SP4 contained few patients and thus was harder to interpret. It differed from SP3 via higher SBP, higher EF, and seemingly better prognosis. SP allocation was driven by subsets of proteins associated with various biological functions and diseases, e.g. myocardial stress, inflammation, and renal dysfunction. Clinical characteristics of the SPs were aligned with these associations. The prognostic model using SPs based on repeated measurements had a better fit than using SPs based on baseline values (c-index: 0.78 vs 0.72). Conclusions: We found 4 circulating-protein based HFrEF subphenotypes driven by varying protein subsets, with different clinical characteristics and prognosis. Repeated protein measurements improved discriminative ability of the subphenotypes for clinical outcomes.

Local empirical model of ionospheric variability

The paper presents an analysis of the ionospheric variability as a function of local time, month, and geomagnetic activity level. The 2003–2020 dataset of peak electron densities (NmF2) from the Irkutsk DPS-4 Digisonde (52.3°N, 104.3°E) was converted into the dataset of the NmF2 disturbances (ΔNmF2) representing the relative (percentage) deviations of the NmF2 from the 27-day running median. The ΔNmF2 dataset was used to calculate root mean square values of ΔNmF2 (σNmF2) by 27-day running averaging. These σNmF2 values were considered as a measure of ionospheric variability. The σNmF2 as function of local time, day of year, and year was the input for building the local empirical model of ionospheric variability based on the linear regression of σNmF2 on the 27-day average daily Ap-index of geomagnetic activity. The paper demonstrates the diurnal-seasonal variations in σNmF2 under low geomagnetic activity (linear regression intercept) as well as the rate of increase/decrease in σNmF2 with increasing Ap (linear regression slope). The obtained diurnal, seasonal, and geomagnetic activity behavior of σNmF2 is compared with previous studies of ionospheric variability.

The effects of hydrogen treatment in a cigarette smoke solution-induced chronic obstructive pulmonary disease-like changes in an animal model.

Molecular hydrogen, with its antioxidant and anti-inflammatory properties, may be suitable for the prevention and treatment of chronic obstructive pulmonary disease (COPD). This study aims to investigate the therapeutic efficacy of hydrogen-oxygen (H2/O2) treatment in cigarette smoke solution (CSS)-induced COPD-like injury in a female BALB/c mouse model. Thirty mice were randomly assigned to three groups: Control (n=8), COPD (n=10), and COPD + H2/O2 (n=12). CSS was administered by intraperitoneal (IP) injection twice weekly for 6 weeks during the COPD induction phase. Simultaneously, the COPD + H2/O2 group started received 75 minutes of inhalation therapy (42% H2) delivered by the Oxy-Hydrogen Generator twice daily for 9 weeks. Mice body weights and survival were measured throughout the study period. Neutrophil elastase (NE) activity and lung histopathological changes were also evaluated. The results showed a higher survival rate in the COPD + H2/O2 group compared to the COPD group (100% vs. 80%) during the induction phase. Slight decreases in body weight gains were observed in the COPD and COPD + H2/O2 groups during the first 15 days of the induction phase, but there was no significant difference in mean body weights among the three groups throughout the study period. NE activity was numerically lower in the COPD + H2/O2 group compared to the COPD group. The histopathological evaluation showed significant improvements in the H2/O2-treated mice with respect to mean linear intercept (MLI) and lesion (inflammation and emphysema) scores. Improvements in goblet cell hypertrophy and hyperplasia of airway epithelium were not significant. A 9-week H2/O2 inhalation therapy delivered by the Oxy-Hydrogen Generator to CSS-induced COPD-like injury in mice showed improvement in survival rate, alveolar structural changes, and histopathological lesion scores of the lung.

Investigating the Effect of Al- 1050-H4 Sample Position on Grain Size and Mechanical Properties During Accumulative Roll Bonding Process

— Nanocrystalline material polycrystals with grain sizes less than 100 nm—have the unique mechanical properties highly desirable for a wide range of applications. This paper compares the microstructure, grain sizes and hardness of top and bottom Al 1050-H4 rolled samples through an accumulative roll bonding process. The samples were rolled once at the speed of 9 rpm and an applied load of 5 ton. Rolled samples were characterised by optical microscopy and a linear intercept method based on the ASTM E122-12 standard was followed. The hardness test was performed on both samples following the ASTM E384 test standard. Simulation was performed using an Auto Desk Inventor and the mesh sizes of the samples were correlated with their grain sizes to analyse the material properties during the accumulative roll bonding (ARB). The obtained results show more property enhancement under the applied load and strain during the ARB process. The bottom sample was more refined and had higher mechanical properties (hardness) compared to the top sample. The average grain size of the bottom sample was 42.6 µm , and 47.6 µm for the top sample. The hardness results were 51.28 HV for the bottom sample and 42.08 HV for the top sample. From the simulation, it was observed that the elongation was useful, without any possibility of material failure in both 42.6 µm and 47.6 µm microstructural analyses. It was also observed that the elongation during the ARB process occurred without any material defects during the grain refining process. The length of the elongation during the ARB process was also revealed during the simulation process. . Keywords—ARB, properties, elongation, material, samples.

AMPK-driven Macrophage Responses Are Autophagy Dependent in Experimental Bronchopulmonary Dysplasia.

The pathogenesis of bronchopulmonary dysplasia (BPD) remains incompletely understood. Recent studies suggest insufficient AMP-activated protein kinase (AMPK) activation as a potential cause of impaired autophagy in rodent and nonhuman primate models of BPD. Impaired autophagy is associated with enhanced inflammatory signaling in alveolar macrophages (AMs) and increased severity of murine BPD induced by neonatal hyperoxia exposure. The goal of this study was to determine the role of autophagy and AMPK activation in macrophage responses in murine BPD. C57BL/6J mice were exposed to neonatal hyperoxia starting on postnatal day (P)1 and treated with the AMPK activator 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) between P3 and P6. Mice were euthanized on P7, and markers of AMPK activation and autophagy were assessed by immunoblotting. Alveolarization was assessed using radial alveolar counts, mean linear intercept measurements, and quantification of alveolar septal myofibroblasts. Relative mRNA expression of M1-like and M2-like genes was assessed in AMs isolated from BAL fluid from wild-type, LysMCre--Becn1fl/fl, and LysMCre+-Becn1fl/fl mice after neonatal hyperoxia exposure. AICAR treatment resulted in AMPK activation and induction of autophagic activity in whole-lung and BAL cell lysates and attenuated hyperoxia-induced alveolar simplification in neonatal lungs. AICAR-treated control but not Beclin1-deficient AMs demonstrated significantly decreased expression of M1-like markers and significantly increased expression of M2-like markers. In conclusion, pharmacologic activation of AMPK by AICAR resulted in induction of autophagy and played a protective role, at least in part, through attenuation of proinflammatory signaling in AMs via autophagy-dependent mechanisms in a murine model of BPD.

Assessment of pulmonary morphometry using hyperpolarized 129 Xe diffusion-weighted MRI with variable-sampling-ratio compressed sensing patterns.

Hyperpolarized (HP) 129 Xe multiple b-values diffusion-weighted magnetic resonance imaging (DW-MRI) has been widely used for quantifying pulmonary microstructural morphometry. However, the technique requires long acquisition times, making it hard to apply in patients with severe pulmonary diseases, who cannot sustain long breath holds. To develop and evaluate the technique of variable-sampling-ratio compressed sensing (VCS) patterns for accelerating HP 129 Xe multiple b-values DW-MRI in humans. Optimal variable sampling ratios and corresponding k-space undersampling patterns for each b-value were obtained by retrospective simulations based on the fully sampled (FS) DW-MRI dataset acquired from six young healthy volunteers. Then, the FS datasets were retrospectively undersampled using both VCS patterns and conventional compressed sensing (CS) pattern with a similar average acceleration factor. The quality of reconstructed images with retrospective VCS (rVCS) and CS (rCS) datasets were quantified using mean absolute error (MAE) and structural similarity (SSIM). Pulmonary morphometric parameters were also evaluated between rVCS and FS datasets. In addition, prospective VCS multiple b-values 129 Xe DW-MRI datasets were acquired from 14 cigarette smokers and 13 age-matched healthy volunteers. The differences of lung morphological parameters obtained with the proposed method were compared between the groups using independent samples t-test. Pearson correlation coefficient was also utilized for evaluating the correlation of the pulmonary physiological parameters obtained with VCS DW-MRI and pulmonary function tests. Lower MAE and higher SSIM values were found in the reconstructed images with rVCS measurement when compared to those using conventional rCS measurement. The details and quality of the images obtained with rVCS and FS measurements were found to be comparable. The mean values of the morphological parameters derived from rVCS and FS datasets showed no significant differences (p>0.05), and the mean differences of measured acinar duct radius, mean linear intercept, surface-to-volume ratio, and apparent diffusion coefficient with cylinder model were -0.87%, -2.42%, 2.04%, and -0.50%, respectively. By using the VCS technique, significant differences were delineated between the pulmonary morphometric parameters of healthy volunteers and cigarette smokers (p<0.001), while the acquisition time was reduced by four times. A fourfold reduction in acquisition time was achieved using the proposed VCS method while preserving good image quality. Our preliminary results demonstrated that the proposed method can be used for evaluating pulmonary injuries caused by cigarette smoking and may prove to be helpful in diagnosing lung diseases in clinical practice.

Effect of individual characteristics and aerobic training on the %HRR-%V̇O2R relationship

ABSTRACT This study aimed to assess if, during incremental exercise, considering individual characteristics can make the relationship between the percentages of heart rate (HRR) and oxygen uptake (V̇O2R) reserve either 1:1 or more accurate. Cycle ergometer data of the maximal incremental exercise tests performed by 450 healthy and sedentary participants (17-66 years) of the HERITAGE Family Study, grouped for sex, ethnicity, age, body fat, resting HR, and V̇O2max, were used to calculate the individual linear regressions between %HRR and %V̇O2R. The mean slope and intercept of the individual linear regressions of each subgroup were compared with 1 and 0 (identity line), respectively, using Hotelling tests followed by post-hoc one-sample t-tests. Two multiple linear regressions were also performed, using either the slopes or intercepts of the individual linear regressions as dependent variables and sex, age, resting HR, and V̇O2max as independent variables. The mean %HRR-%V̇O2R relationships of all subgroups differed from the identity line. Moreover, individual linear regression intercepts (8.9 ± 16.0) and slopes (0.971 ± 0.190) changed (p < 0.001) after 20 weeks of aerobic training (13.1 ± 11.1 and 0.891 ± 0.122). The multiple linear regressions could explain only 3.8% and 1.3% of the variance in the intercepts and slopes, whose variability remained high (standard error of estimate of 15.8 and 0.189). In conclusion, the %HRR-%V̇O2R relationship differs from the identity line regardless of individual characteristics and their difference increased after aerobic training. Moreover, due to the high interindividual variability, using a single equation for the whole population seems not suitable for representing the %HRR-%V̇O2R relationship of a given subject, even when several individual characteristics are considered. Highlights The association between %HRR and %V̇O2R is not 1:1 even when individuals are grouped by age, sex, ethnicity, body composition, HRrest, and V̇O2max. Using several subject characteristics to identify the individual’s %HRR-%V̇O2R relationship does not meaningfully increase its prediction accuracy or reduce the interindividual variability of %HRR-%V̇O2R relationships Using a single equation for the whole population is not suitable for representing the relationship of a given subject; hence, individual relationships should be preferred when prescribing the intensity of aerobic exercise. The individual %HRR-%V̇O2R relationship should be periodically assessed due to the potential training induced changes in the relationship.

Fetal Lung Cells Transfer Improves Emphysematous Change in a Mouse Model of Neutrophil Elastase-Induced Lung Emphysema

Recently, several studies for lung regeneration have been reported. However, regenerating the lung tissue by the transfer of any cells directly to the lung has been hardly successful. The aim of this study was to evaluate the effect of fetal lung cells (FLCs) in a mouse model of lung emphysema. C57BL/6 mice were stimulated with neutrophil elastase (NE) intra-tracheally (i.t.) to generate lung emphysema. To collect fetal lung cells, C57BL/6-Tg (CAG-EGFP) mice were bred for 14 days. Before delivery, the bred mice were euthanized, and fetal lungs were harvested from the fetal mice and the cells were collected. The FLCs were transferred i.t. 24 h after the NE instillation. Four weeks after the NE instillation, mice were euthanized, and the samples were collected. The mean linear intercept (MLI) was significantly prolonged in the NE instillation group compared to the control group. However, in the FLCs transfer group stimulated with NE, the MLI became shorter than the NE-stimulated group without an FLCs transfer. This result shows that an FLCs transfer inhibited the progression of lung emphysema. Additionally, motility of the mice was also improved by the FLCs transfer. These results indicate that transfer of the FLCs, which were presumed to be progenitor cells for lung tissue, may improve the emphysematous change.

Exosomes derived from human umbilical cord mesenchymal stem cells protect against papain-induced emphysema by preventing apoptosis through activating VEGF-VEGFR2-mediated AKT and MEK/ERK pathways in rats.

IntroductionChronic obstructive pulmonary disease (COPD) is a leading cause of high mortality and heavy burden in the world. Unfortunately, emphysema, as an important component of COPD, has no curative treatments currently. Recently, human umbilical cord mesenchymal stem cells-derived exosomes (hUCMSC-Ex) constitute a promising alternative approach for tissue regeneration and repair. However, the roles of hUCMSC-Ex in emphysema and its mechanism are largely unknown. Here, we investigated the effect and the action mechanism of hUCMSC-Ex in repairing emphysema induced by papain in rats.MethodsSD rats were used to establish a papain-induced emphysema model and estimate the effect and mechanism of hUCMSC-Ex treatment. H&E staining and mean linear intercept (MLI) were used to evaluate the hUCMSC-Ex effect on emphysema. Western blotting, TUNEL and miRNA-seq were used to investigate the molecular mechanisms of hUCMSC-Ex treatment in models of papain-induced emphysema.ResultsPapain treatment led to typical emphysema, while hUCMSC-Ex reversed emphysematous changes effectively. Apoptosis of endothelial cells and other types of cells were observed in models, while hUCMSC-Ex effectively prevented their apoptosis. hUCMSC-Ex repressed active caspase-3, activated VEGF-VEGFR2-mediated AKT pathway and MEK/ERK pathway in emphysematous lungs. Notably, several miRNAs, such as hsa-miR-10a-5p and hsa-miR-146a-5p, were target related to the roles of hUCMSC-Ex in papain-induced emphysema through VEGF-VEGFR2-mediated AKT and MEK/ERK pathways.ConclusionshUCMSC-Ex effectively rescued the papain-induced emphysema injury through VEGF-VEGFR2-mediated AKT pathway and MEK/ERK pathway.

Physical Distancing and Social Media Use in Emerging Adults and Adults During the COVID-19 Pandemic: Large-scale Cross-sectional and Longitudinal Survey Study.

BackgroundAlthough emerging adults play a role in the spread of COVID-19, they are less likely to develop severe symptoms after infection. Emerging adults’ relatively high use of social media as a source of information raises concerns regarding COVID-19–related behavioral compliance (ie, physical distancing) in this age group.ObjectiveThis study aimed to investigate physical distancing among emerging adults in comparison with adults and examine the role of using social media for COVID-19 news and information in this regard. In addition, this study explored the relationship between physical distancing and using different social media platforms and sources.MethodsThe secondary data of a large-scale longitudinal national survey (N=123,848) between April and November 2020 were used. Participants indicated, ranging from 1 to 8 waves, how often they were successful in keeping a 1.5-m distance on a 7-point Likert scale. Participants aged between 18 and 24 years were considered emerging adults, and those aged >24 years were considered adults. In addition, a dummy variable was created to indicate per wave whether participants used social media for COVID-19 news and information. A subset of participants received follow-up questions to determine which platforms they used and what sources of news and information they had seen on social media. All preregistered hypotheses were tested with linear mixed-effects models and random intercept cross-lagged panel models.ResultsEmerging adults reported fewer physical distancing behaviors than adults (β=−.08, t86,213.83=−26.79; P<.001). Moreover, emerging adults were more likely to use social media for COVID-19 news and information (b=2.48; odds ratio 11.93 [95% CI=9.72-14.65]; SE 0.11; Wald=23.66; P<.001), which mediated the association with physical distancing but only to a small extent (indirect effect: b=−0.03, 95% CI −0.04 to −0.02). Contrary to our hypothesis, the longitudinal random intercept cross-lagged panel model showed no evidence that physical distancing was not influenced by social media use in the previous wave. However, evidence indicated that social media use affects subsequent physical distancing behavior. Moreover, additional analyses showed that the use of most social media platforms (ie, YouTube, Facebook, and Instagram) and interpersonal communication were negatively associated with physical distancing, whereas other platforms (ie, LinkedIn and Twitter) and government messages had no or small positive associations with physical distancing.ConclusionsIn conclusion, we should be vigilant with regard to the physical distancing of emerging adults, but the study results did not indicate concerns regarding the role of social media for COVID-19 news and information. However, as the use of some social media platforms and sources showed negative associations with physical distancing, future studies should more carefully examine these factors to better understand the associations between social media use for news and information and behavioral interventions in times of crisis.

Reduction of Emphysema Severity by Human Umbilical Cord-Derived Mesenchymal Stem Cells in Mice.

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality in chronic lung disease patients throughout the world. Mesenchymal stem cells (MSCs) have been shown to regulate immunomodulatory, anti-inflammatory, and regenerative responses. However, the effects of human-umbilical-cord-derived mesenchymal stem cells (hUC-MSCs) on the lung pathophysiology of COPD remain unclear. We aimed to investigate the role of hUC-MSCs in emphysema severity and Yes-associated protein (Yap) phosphorylation (p-Yap) in a porcine-pancreatic-elastase (PPE)-induced emphysema model. We observed that the emphysema percentages (normalized to the total lung volume) measured by chest computed tomography (CT) and exercise oxygen desaturation were significantly reduced by hUC-MSCs at 107 cells/kg body weight (BW) via intravenous administration in emphysematous mice (p < 0.05). Consistently, the emphysema index, as assessed by the mean linear intercept (MLI), significantly decreased with hUC-MSC administration at 3 × 106 and 107 cells/kg BW (p < 0.05). Changes in the lymphocytes, monocytes, and splenic cluster of differentiation 4-positive (CD4+) lymphocytes by PPE were significantly reversed by hUC-MSC administration in emphysematous mice (p < 0.05). An increasing neutrophil/lymphocyte ratio was reduced by hUC-MSCs at 3 × 106 and 107 cells/kg BW (p < 0.05). The higher levels of tumor necrosis factor (TNF)-α, keratinocyte chemoattractant (KC), and lactate dehydrogenase (LDH) in bronchoalveolar lavage fluid (BALF) were significantly decreased by hUC-MSC administration (p < 0.05). A decreasing p-Yap/Yap ratio in type II alveolar epithelial cells (AECII) of mice with PPE-induced emphysema was significantly increased by hUC-MSCs (p < 0.05). In conclusion, the administration of hUC-MSCs improved multiple pathophysiological features of mice with PPE-induced emphysema. The effectiveness of the treatment of pulmonary emphysema with hUC-MSCs provides an essential and significant foundation for future clinical studies of MSCs in COPD patients.

Vitamin D Ameliorates Apoptosis and Inflammation by Targeting the Mitochondrial and MEK1/2-ERK1/2 Pathways in Hyperoxia-Induced Bronchopulmonary Dysplasia

PurposeBronchopulmonary dysplasia (BPD) is a common and severe complication in preterm infants. Vitamin D (VitD) has been reported to protect against BPD; however, its role in the mitochondria-mediated and MEK1/2-ERK1/2 pathways has not yet been reported.MethodsWe first performed in vivo studies using neonatal C57BL/6 mice in which we induced BPD by exposing them to a hyperoxic environment (85% O2). The mice were divided into room air (RA; 21% O2), RA+VitD, BPD, and BPD+VitD groups. Hematoxylin and eosin and Masson’s trichrome staining were used to evaluate lung injury. Inflammation and apoptosis were measured using ELISA, RT-qPCR, and TUNEL assays. We then analyzed BEAS-2B cells divided into the same groups along with an additional BPD+VitD+inhibitor group. Mitochondrial apoptosis was evaluated by transmission electron microscopy, mitochondrial membrane potential, and Western blotting. We then used VDR-shRNA to silence the Vitamin D Receptor (VDR) in the BEAS-2B cells. The inflammation, apoptotic rate, and the phosphorylated forms of MEK1/2 and ERK1/2 in cells were detected by RT-qPCR, flow cytometry, and Western blotting.ResultsThe mean linear intercept, septal thickness, and abnormal fibrosis increased, while radial alveolar count decreased in BPD lungs compared to RA lungs. VitD administration was able to ameliorate the phenotype in BPD lungs. IL-6, IFN-γ, and TNF-α expression and the apoptotic rate decreased in the BPD+VitD lung group. VitD pretreatment restored abnormal mitochondrial morphology, reduced mitochondrial membrane loss, and reduced the expression of cleaved caspase-3, Bax, and Bcl-2 in BEAS-2B cells. VitD administration also reduced IL-6, IFN-γ, and TNF-α mRNA, as well as pMEK1/2 and pERK1/2 expression and apoptosis rate in cells exposed to hyperoxia.ConclusionWe concluded that VitD treatment ameliorated apoptosis and inflammation by targeting the mitochondrial pathway and via the MEK1/2-ERK1/2 signaling pathway in BPD, thus supporting its potential therapeutic use in this condition.

A Mg-6Y-3Zn-1Al Mg HPDC alloy having high thermal stability: Study of grain growth kinetics

The thermal stability and grain growth kinetics of a high-pressure die casting (HPDC) Mg-6Y–3Zn-1Al (WZA631, wt%) alloy with long-period stacking ordered (LPSO) phase is studied by subsequent annealing at different temperatures and time. The grain size of the as-cast and annealed samples is determined using the linear intercept method. It is found that grain size of WZA631 alloy hardly changes up to 450 °C, indicating the microstructure is thermally stable. The grain growth kinetics of WZA631 alloy between 450 °C and 550 °C is well described by the kinetic equation, Dn−D0n=kt. The grain growth exponent varies with temperature, ranging from n = 4.98 at 450 °C to n = 1.45 at 550 °C. The values of activation energy Eg are approximately 122.5 kJ/mol and 139.1 kJ/mol, respectively, for annealing temperature below and above 500 °C, which identifies the bulk diffusion to be the principal grain growth mechanism in the studied temperature range. The growth rate constant k at 450–500 °C is around 2–4 orders lower than other typical Mg alloys, suggesting the excellent thermal stability below 500 °C. The grain coarsening temperature TGC and softening temperature TS are all around 500 °C, implying the critical temperature related to the thermal stability of WZA631 alloy is ~500 °C. The microstructure evolution shows that LPSO network structure is a predominant factor inhibiting the grain growth of HPDC WZA631 alloy, and the dissolution of LPSO results in the variation of grain growth exponent.

Intratracheal administration of umbilical cord-derived mesenchymal stem cells attenuates hyperoxia-induced multi-organ injury via heme oxygenase-1 and JAK/STAT pathways.

BACKGROUNDBronchopulmonary dysplasia (BPD) is not merely a chronic lung disease, but a systemic condition with multiple organs implications predominantly associated with hyperoxia exposure. Despite advances in current management strategies, limited progress has been made in reducing the BPD-related systemic damage. Meanwhile, although the protective effects of human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) or their exosomes on hyperoxia-induced lung injury have been explored by many researchers, the underlying mechanism has not been addressed in detail, and few studies have focused on the therapeutic effect on systemic multiple organ injury. AIMTo investigate whether hUC-MSC intratracheal administration could attenuate hyperoxia-induced lung, heart, and kidney injuries and the underlying regulatory mechanisms.METHODSNeonatal rats were exposed to hyperoxia (80% O2), treated with hUC-MSCs intratracheal (iT) or intraperitoneal (iP) on postnatal day 7, and harvested on postnatal day 21. The tissue sections of the lung, heart, and kidney were analyzed morphometrically. Protein contents of the bronchoalveolar lavage fluid (BALF), myeloperoxidase (MPO) expression, and malondialdehyde (MDA) levels were examined. Pulmonary inflammatory cytokines were measured via enzyme-linked immunosorbent assay. A comparative transcriptomic analysis of differentially expressed genes (DEGs) in lung tissue was conducted via RNA-sequencing. Subsequently, we performed reverse transcription-quantitative polymerase chain reaction and western blot analysis to explore the expression of target mRNA and proteins related to inflammatory and oxidative responses.RESULTSiT hUC-MSCs administration improved pulmonary alveolarization and angiogenesis (P < 0.01, P < 0.01, P < 0.001, and P < 0.05 for mean linear intercept, septal counts, vascular medial thickness index, and microvessel density respectively). Meanwhile, treatment with hUC-MSCs iT ame liorated right ventricular hypertrophy (for Fulton’s index, P < 0.01), and relieved reduced nephrogenic zone width (P < 0.01) and glomerular diameter (P < 0.001) in kidneys. Among the beneficial effects, a reduction of BALF protein, MPO, and MDA was observed in hUC-MSCs groups (P < 0.01, P < 0.001, and P < 0.05 respectively). Increased pro-inflammatory cytokines tumor necrosis factor-alpha, interleukin (IL)-1β, and IL-6 expression observed in the hyperoxia group were significantly attenuated by hUC-MSCs administration (P < 0.01, P < 0.001, and P < 0.05 respectively). In addition, we observed an increase in anti-inflammatory cytokine IL-10 expression in rats that received hUC-MSCs iT compared with rats reared in hyperoxia (P < 0.05). Tran scriptomic analysis showed that the DEGs in lung tissues induced by hyperoxia were enriched in pathways related to inflammatory responses, epithelial cell proliferation, and vasculature development. hUC-MSCs administration blunted these hyperoxia-induced dysregulated genes and resulted in a shift in the gene expression pattern toward the normoxia group. hUC-MSCs increased heme oxygenase-1 (HO-1), JAK2, and STAT3 expression, and their phosphorylation in the lung, heart, and kidney (P < 0.05). Remarkably, no significant difference was observed between the iT and iP administration. CONCLUSIONiT hUC-MSCs administration ameliorates hyperoxia-induced lung, heart, and kidney injuries by activating HO-1 expression and JAK/STAT signaling. The therapeutic benefits of local iT and iP administration are equivalent.