Experimental Lung Research最新文献

Organic anion transport polypeptide 2B1 (OATP2B1), as an uptake transporter, is involved in the transport of many related substrate drugs and endogenous substances in the lungs. A large amount of data shows that cigarette smoke plays an important role in the occurrence and development of lung diseases such as chronic obstructive pulmonary disease (COPD), asthma and bronchitis. However, the effect of cigarette smoke combined with lipopolysaccharide-induced pulmonary inflammation on the expression of OATP2B1 is not clear. In this study, we used cigarette smoke combined with lipopolysaccharide to establish a lung inflammation model in vivo and in vitro to explore the effect of inflammation on the expression of OATP2B1. Our study found that cigarette smoke combined with lipopolysaccharide-induced pulmonary inflammation upregulated the mRNA and protein expression of OATP2B1 and related inflammatory factors, and the expression level of related proteins was higher with the aggravation of inflammation. The experimental results of animals in vivo were consistent with those of cells in vitro. In summary, these findings provide a model and basis for a follow-up study of the mechanism of OATP2B1 in pulmonary inflammation.

Objectives: This study aimed to evaluate the effect of a preliminary bronchodilator dose on the aerosol-d elivery by different nebulizers in noninvasively ventilated chronic obstructive pulmonary disease (COPD) patients. Method: COPD patients were randomized to receive study doses of 800 µg beclomethasone dipropionate (BPD) nebulized by either a vibrating mesh nebulizer (VMN) or a jet nebulizer (JN) connected to MinimHal spacer device. On a different day, the nebulized dose of beclomethasone was given to each patient by the same aerosol generator with and without preceded two puffs (100 µg each) of salbutamol delivered by a pressurized-metered dose inhaler. Urinary BPD and its metabolites in 30 min post-inhalation samples and pooled up to 24 h post-inhalation were measured. On day 2, ex-vivo studies were performed with BPD collected on filters before reaching patients which were eluted from filters and analyzed to estimate the total emitted dose.Results: The highest urinary excretion amounts of BPD and its metabolites 30 min and 24 h post-inhalation were identified with pMDI + VMN compared with other regimens(p < 0.001). The amounts of BPD and its metabolites excreted 30 min post inhalation had approximately doubled with pMDI + JN compared with JN delivery (p < 0.05). No significant effect was found in the ex-vivo study results except between VMN and JN with a significant superiority of the VMN (p < 0.001).Conclusion: Using a preliminary bronchodilator dose before drug nebulization significantly increased the effective lung dose of the nebulized drug with both VMNs and JNs. However, adding a preliminary bronchodilator dose increased the 24 hr cumulative urinary amount of the drug representing higher systemic delivery of the drug, which in turn could result in higher systemic side effects.

Purpose: Cellular senescence and mitochondrial fragmentation are thought to be crucial components of the cigarette smoke(CS)-induced responses that contribute to the chronic obstructive pulmonary disease (COPD) development as a result of accelerated premature aging of the lung. Although there have been a few reports on the role of sirtuin 1(SIRT1) in mitochondrial homeostasis, senescence and inflammation, whether SIRT1/FOXO3/PINK1 signaling mediated mitophagy ameliorates cellular senescence in COPD is still unclear. This study aimed to ascertain whether SIRT1 regulates cellular senescence via FOXO3/PINK1-mediated mitophagy in COPD. Methods: To investigate the effect of CS exposure and SIRT1 deficiency on mitophagy and senescence in the lung, a SIRT1 knockout(KO) mouse model was used. Airway resistance, cellular senescence mitochondrial injury, mitophagy, cellular architecture and protein expression levels in lung tissues, from SIRT1 KO and wild-type(WT) COPD model mice exposed to CS for 6 months were examined by western blotting, histochemistry, immunofluorescence and transmission electron microscopy(TEM). Results: In CS exposed mice, SIRT1 deficiency exacerbated airway resistance and cellular senescence, increased FOXO3 acetylation and decreased PINK1 protein levels and attenuated mitophagy. Mechanistically, the damaging effect of SIRT1 deficiency on lung tissue was attributed to increased FOXO3 acetylation and decreased PINK1 levels, and attenuated mitophagy. In vitro, mitochondrial damage and cellular sensitivity in response to CS exposure were more severe in control cells than in cells treated with aSIRT1 activator. SIRT1 activation SIRT1 activation decreased FOXO3 acetylation and increased the protein levels of PINK1 and enhanced mitophagy. Conclusion: These results demonstrated that the detrimental effects of SIRT1 deficiency on cell senescence associated with insufficient mitophagy, and involved the FOXO3/PINK1 signaling pathway.

Purpose: Characterization of the respiratory tract bacterial microbiome is in its infancy when compared to the gut microbiota. To limit bias mandates a robust methodology. Specific amplification of the hypervariable (V) region of the 16SrRNA gene is a crucial step. Differences in accuracy exist for one V region to another depending on the sampled environment. We aimed to assess the impact of the primer sequences targeting the V4 region currently used for gut microbiota studies in respiratory samples. Materials and methods: The original 515 F-806R primer pair targets the V4 region of the 16SrRNA gene. We compared two different 515 F-806R primer pairs before Illumina 250 paired-end sequencing for bacterial microbiome analyses of respiratory samples from critically-ill ventilated patients. "S-V4" for "Stringent V4" primer pair is used in two ongoing international projects "the Integrative Human microbiome project (iHMP)" and "the Earth microbiome project (EMP)." "R-V4" for "Relaxed V4" primer pair has been modified to reduce biases against specific environmental taxa. The optimal method was determined by concordance with conventional microbiology. Results: Twenty samples from three patients who developed a ventilator-associated pneumonia (VAP) and four who did not (control ventilated patients) were sequenced. Highly different results were obtained. "S-V4" provided the best agreement with the conventional microbiology for endotracheal aspirate: 89% as compared to 56% for "R-V4." The main difference related to poor Enterobacteriaceae detection with "R-V4" primers. Conclusions: Accuracy of the bacterial lung microbiome composition was highly dependent on the primers used for amplification of the 16 s rRNA hypervariable sequence. This work validates for future lung microbiome studies the use of the 515 F-806R "S-V4" primer pair associated to Illumina® MiSeq paired-end sequencing.

There is no ideal method for determination of positive end-expiratory pressure (PEEP) in acute respiratory distress syndrome (ARDS) patients. We compared the effects of end-expiratory lung volume (EELV)-guided versus PaO₂-guided PEEP determination on respiratory mechanics and oxygenation during the first 48 hours in moderate to severe ARDS.

Twenty-two patients with moderate to severe ARDS admitted to an academic medical ICU were assigned to PaO₂-guided (n = 11) or to EELV-guided PEEP determination (n = 11) group. First, an incremental PEEP trial was performed by increasing PEEP by 3 cmH₂O steps from 8 to 20 cmH₂O and in each step EELV and lung mechanics were measured in both groups. Then, oxygenation and respiratory mechanics were measured under the determined PEEP at 4, 12, 24, and 48th hours.

After the incremental PEEP trial, over the 48 hours of the study period, in the EELV-guided group PaO₂ and PaO₂/FiO₂ increased (p = 0.04 and p = 0.02; respectively), whereas they did not change in PaO₂-guided group (p = 0.09 and p = 0.27; respectively). In all patients, the median value of EELV change (ΔEELV) during incremental PEEP trial was 25%. In patients with ΔEELV > 25% (n = 11) PaO₂, PaO₂/FiO₂ and Cs increased over time in 48 hours (p = 0.03, p < 0.01, and p = 0.04; respectively), whereas they did not change in those with ΔEELV ≤ 25% (n = 11) (p = 0.73, p = 0.51, and p = 0.73; respectively).

Compared to PaO₂-guided PEEP determination, EELV-guided PEEP determination resulted in greater improvement in oxygenation over time. Patients who had > 25% improvement in EELV during a PEEP trial had greater improvement in oxygenation and compliance over 48 hours.

Supplemental data for this article is available online at.

Materials and methods: We investigated BMPR2 expression in pulmonary fibrosis and TGF-β/BMP signaling in lung fibroblasts. Then we evaluated the impact of BMPR2 upregulation using adenoviral transduction on TGF-β-induced Smad2/3 phosphorylation and fibronectin production in lung fibroblasts.

Results: BMPR2 was distributed in airway epithelium and alveolar walls in rat lungs. BMPR2 expression was decreased in fibrotic lesions in the lungs of rats with bleomycin-induced pulmonary fibrosis and in human lung fibroblasts (HLFs) stimulated with TGF-β. Although Smad2/3 phosphorylation and fibronectin production were not suppressed solely by BMPs, phosphorylated Smad2/3 was decreased in BMPR2-transduced cells even without BMP stimulation. Fibronectin was decreased only when BMPR2-transduced HLFs were stimulated with BMP7 (but not BMP4). Similar results were also observed in IPF patient HLFs and rat lung fibroblasts.

Conclusions: BMPR2 expression was reduced in fibrotic lungs and lung fibroblasts stimulated with TGF-β. BMPR2 transduction to lung fibroblasts reduced Smad2/3 phosphorylation, and reduced fibronectin production when treated with BMP7. Upregulation of BMPR2 may be a possible strategy for treating pulmonary fibrosis.