Targeting Rev-Erbα to protect against ischemia-reperfusion-induced acute lung injury in rats.

BACKGROUND: The dysregulation of local circadian clock has been implicated in the pathogenesis of a broad spectrum of diseases. However, the pathophysiological role of intrinsic circadian clocks Rev-Erbα in ischemia-reperfusion (IR)-induced acute lung injury (ALI) remains unclear. METHODS: The IR-ALI model was established by subjecting isolated perfused rat lungs to 40 min of ischemia followed by 60 min of reperfusion. Rats were randomly assigned to one of six groups: control, control + SR9009 (Rev-Erbα agonist, 50 mg/kg), IR, and IR + SR9009 at one of three dosages (12.5, 25, 50 mg/kg). Bronchoalveolar lavage fluids (BALF) and lung tissues were obtained and analyzed. In vitro experiments utilized mouse lung epithelial cells (MLE-12) exposed to hypoxia-reoxygenation (HR) and pretreated with SR9009 (10 µM/L) and Rev-Erbα siRNA. RESULTS: SR9009 exhibited a dose-dependent reduction in lung edema in IR-ALI. It significantly inhibited the production of TNF-α, IL-6, and CINC-1 in BALF. Moreover, SR9009 treatment restored suppressed IκB-α levels and reduced nuclear NF-κB p65 levels in lung tissues. In addition, a SR9009 mitigated IR-induced apoptosis and mitogen-activated protein kinase (MAPK) activation in injured lung tissue. Finally, treatment with Rev-Erbα antagonist SR8278 abolished the protective action of SR9009. In vitro analyses showed that SR9009 attenuated NF-κB activation and KC/CXCL-1 levels in MLE-12 cells exposed to HR, and these effects were significantly abrogated by Rev-Erbα siRNA. CONCLUSIONS: The findings suggest that SR9009 exerts protective effects against IR-ALI in a Rev-Erbα-dependent manner. SR9009 may provide a novel adjuvant therapeutic approach for IR-ALI.

MRI contributes to accurate and early diagnosis of non-radiographic HLA-B27 negative axial spondyloarthritis.

BACKGROUND: Nonradiographic axial spondyloarthropathies (nr-axSpA) are diagnosed by the absence of radiographic sacroiliitis and the presence of bone marrow edema (BME) on magnetic resonance imaging (MRI). According to the classification criteria of the international Assessment of Spondyloarthritis Society (ASAS), structural changes to sacroiliac joints (SIJs) on MRI cannot be used as criteria in the absence of BME. However, less than half the Asian patients with clinically active axSpA show BME. The incidence of human leukocyte antigen (HLA)-B27 is low in Asian populations, which makes it more difficult to identify nr-axSpA. We used MRI to evaluate the structural damage to SIJs in patients with nr-axSpA with and without BME with the aim of identifying the best methodology for accurate diagnosis, especially in populations with less common BME and HLA-B27. METHODS: One hundred three patients with inflammatory back pain were included in this prospective study. No patient's radiograph met the definition of positive modified New York criteria. BME and structural damage to SIJ including sclerosis and erosion were assessed independently on coronal and axial short-tau inversion recovery and T1-weighted spin echo MRI scans by two well-trained musculoskeletal radiologists using the Spondyloarthritis Research Consortium of Canada (SPARCC) score. Demographics of patients were collected. Disease characteristics and structural damage were analyzed in patients with and without BME on SIJ MRI. Receiver operating characteristic (ROC) curve analysis was used to assess the diagnostic performance of structural damage. RESULTS: All individuals in the cohort had at least one abnormal finding on SIJ MRI, including BME or structural damage; 36 of 103 patients had BME. We identified a significant positive correlation between SPARCC scores and severe erosion assessed by focal joint space widening (fJSW) (p = 0.001) in these 36 patients. Fifty-eight of the 103 enrolled patients fulfilled the ASAS criteria for nr-axSpA in the either absence or presence of BME. Of these 58 patients, 57 and 19 had erosions or fJSW, respectively, and the presence of BME was significantly correlated with fJSW (phi score of 0.319 and p = 0.015). We demonstrated a significant positive correlation between fJSW and either the presence or the severity of BME in patients with nr-axSpA who met the ASAS definition. There was a positive correlation between BME and fJSW across the whole study cohort (phi score of 0.389; p < 0.001). The area under the ROC curve (AUC) for fJSW on SIJ MRI was 0.736, p < 0.001. In both HLA-B27-positive and -negative groups, BME was more common in the presence of fJSW (phi scores of 0.370 and 0.377, p = 0.018 and 0.003, respectively) and SPARCC scores were higher in patients with fJSW (p < 0.001 and p = 0.005). We also identified a positive correlation between fJSW and BME in patients with nr-axSpA and normal serum levels of C-reactive protein (phi score of 0.362 and p = 0.001). CONCLUSION: Structural damage detected on SIJ MRI, sclerosis, erosions and fJSW may be present in patients without detectable inflammation on SIJ MRI. However, fJSW is significantly correlated with the severity of inflammation seen on SIJ MRI, which contributes to the accurate diagnosis of nr-axSpA, and it could be used as an alternative diagnostic test for nr-axSpA in the general population, especially for those who do not carry the HLA-B27 gene, Asian patients without BME, or patients with normal serum inflammatory biomarkers.

Melatonin receptor agonist protects against acute lung injury induced by ventilator through up-regulation of IL-10 production.

BACKGROUND: It is well known that ventilation with high volume or pressure may damage healthy lungs or worsen injured lungs. Melatonin has been reported to be effective in animal models of acute lung injury. Melatonin exerts its beneficial effects by acting as a direct antioxidant and via melatonin receptor activation. However, it is not clear whether melatonin receptor agonist has a protective effect in ventilator-induced lung injury (VILI). Therefore, in this study, we determined whether ramelteon (a melatonin receptor agonist) can attenuate VILI and explore the possible mechanism for protection. METHODS: VILI was induced by high tidal volume ventilation in a rat model. The rats were randomly allotted into the following groups: control, control+melatonin, control+ramelteon, control+luzindole, VILI, VILI+luzindole, VILI + melatonin, VILI + melatonin + luzindole (melatonin receptor antagonist), VILI + ramelteon, and VILI + ramelteon + luzindole (n = 6 per group). The role of interleukin-10 (IL-10) in the melatonin- or ramelteon-mediated protection against VILI was also investigated. RESULTS: Ramelteon treatment markedly reduced lung edema, serum malondialdehyde levels, the concentration of inflammatory cytokines in bronchoalveolar lavage fluid (BALF), NF-κB activation, iNOS levels, and apoptosis in the lung tissue. Additionally, ramelteon treatment significantly increased heat shock protein 70 expression in the lung tissue and IL-10 levels in BALF. The protective effect of ramelteon was mitigated by the administration of luzindole or an anti-IL-10 antibody. CONCLUSIONS: Our results suggest that a melatonin receptor agonist has a protective effect against VILI, and its protective mechanism is based on the upregulation of IL-10 production.

Application of classification criteria of Sjogren syndrome in patients with sicca symptoms: Real-world experience at a medical center.

BACKGROUND: Patients who have symptoms of sicca, such as dry eyes and mouth, may have Sjögren's syndrome (SS). However, the conservative culture makes patients hesitate to undergo an invasive biopsy, which contributes to the difficulty of confirming a diagnosis. We aimed to identify the characteristics of patients with sicca symptoms to develop a better predictive value for each item included in the three different diagnostic criteria for SS and clarify the best diagnostic tools for the local population. METHODS: This is a single-center retrospective case-control study from January 2016 to December 2017. Patients who underwent sialoscintigraphy because of clinical symptoms of xerostomia and xerophthalmia at one medical center were reviewed via the patients' electronic medical records. RESULTS: Of 515 patients enrolled, the severity of results for sialoscintigraphy and Schirmer's test was correlated with a diagnosis of SS and generated receiver operator characteristic curve. The area under curve (AUC) was 0.603 for positive Schirmer's test, 0.687 for positive anti-Ro/La results, 0.893 for a positive salivary gland biopsy. The AUC was 0.626 and 0.602 for Schirmer's test which is redefined as <10 mm/5 minutes in either eye and according to 2016 the American College of Rheumatology/ European League Against Rheumatism criteria, respectively. CONCLUSION: Our results indicate the cut-off point for defining a positive test result in the Schirmer's test is worth modified to <10 mm/5 minutes in either eye.

Pre-Treatment with Ten-Minute Carbon Dioxide Inhalation Prevents Lipopolysaccharide-Induced Lung Injury in Mice via Down-Regulation of Toll-Like Receptor 4 Expression.

Various animal studies have shown beneficial effects of hypercapnia in lung injury. However, in patients with acute respiratory distress syndrome (ARDS), there is controversial information regarding the effect of hypercapnia on outcomes. The duration of carbon dioxide inhalation may be the key to the protective effect of hypercapnia. We investigated the effect of pre-treatment with inhaled carbon dioxide on lipopolysaccharide (LPS)-induced lung injury in mice. C57BL/6 mice were randomly divided into a control group or an LPS group. Each LPS group received intratracheal LPS (2 mg/kg); the LPS groups were exposed to hypercapnia (5% carbon dioxide) for 10 min or 60 min before LPS. Bronchoalveolar lavage fluid (BALF) and lung tissues were collected to evaluate the degree of lung injury. LPS significantly increased the ratio of lung weight to body weight; concentrations of BALF protein, tumor necrosis factor-α, and CXCL2; protein carbonyls; neutrophil infiltration; and lung injury score. LPS induced the degradation of the inhibitor of nuclear factor-κB-α (IκB-α) and nuclear translocation of NF-κB. LPS increased the surface protein expression of toll-like receptor 4 (TLR4). Pre-treatment with inhaled carbon dioxide for 10 min, but not for 60 min, inhibited LPS-induced pulmonary edema, inflammation, oxidative stress, lung injury, and TLR4 surface expression, and, accordingly, reduced NF-κB signaling. In summary, our data demonstrated that pre-treatment with 10-min carbon dioxide inhalation can ameliorate LPS-induced lung injury. The protective effect may be associated with down-regulation of the surface expression of TLR4 in the lungs.

Kinect-based real-time audiovisual feedback device improves CPR quality of lower-body-weight rescuers.

BACKGROUND: Chest compression (CC) quality is associated with rescuer posture and body weight. We designed a Kinect module-based real-time audiovisual feedback (AVF) device to investigate the relationship between rescuer posture, body weight, and CC quality. METHODS: A total of 100 healthcare professionals were enrolled as participants in this randomized trial. A Kinect-based sensor system was used to monitor the depth and rate of CC and provide further real-time feedback. All participants were asked to perform continuous CC on a manikin with and without feedback for 2min individually in either a kneeling or standing position. RESULTS: A kneeling posture can provide higher rate of CC than a standing posture can (111.4±22.6 per minute vs. 99.1±18.9per minute, p value=0.005). Real-time AVF feedback can provide a better compression depth, rate, and effective compression ratio (6.16±1.88cm vs. 5.54±1.89cm, p value=0.02; 103.2±21.0/min vs. 96.7±25.8/min, p value=0.03; 62.6±28.0% vs. 51.0±33.2%, p value=0.004). Regardless of the effect of real-time feedback, the CC depth correlated to the rescuers' body weight. Rescuers who weighed below 71kg benefited from the Kinect module-based real-time AVF device in terms of improved CC quality. CONCLUSION: The Kinect-based AVF device can significantly improve CC quality in manikin training in rescuers with their body weight<71kg.

Correction: Wen-I Liao, et al. Ac2-26, an Annexin A1 Peptide, Attenuates Ischemia-Reperfusion-Induced Acute Lung Injury. Int. J. Mol. Sci. 2017, 18, 1771.

The authors would like to make a correction to their published paper [1][...].

Targeting of nicotinamide phosphoribosyltransferase enzymatic activity ameliorates lung damage induced by ischemia/reperfusion in rats.

BACKGROUND: Emerging evidence reveals that nicotinamide phosphoribosyltransferase (NAMPT) has a significant role in the pathophysiology of the inflammatory process. NAMPT inhibition has a beneficial effect in the treatment of a variety of inflammatory diseases. However, it remains unclear whether NAMPT inhibition has an impact on ischemia-reperfusion (I/R)-induced acute lung injury. In this study, we examined whether NAMPT inhibition provided protection against I/R lung injury in rats. METHODS: Isolated perfused rat lungs were subjected to 40 min of ischemia followed by 60 min of reperfusion. The rats were randomly allotted to the control, control + FK866 (NAMPT inhibitor, 10 mg/kg), I/R, or I/R + FK866 groups (n = 6 per group). The effects of FK866 on human alveolar epithelial cells exposed to hypoxia-reoxygenation (H/R) were also investigated. RESULTS: Treatment with FK866 significantly attenuated the increases in lung edema, pulmonary arterial pressure, lung injury scores, and TNF-α, CINC-1, and IL-6 concentrations in bronchoalveolar lavage fluid in the I/R group. Malondialdehyde levels, carbonyl contents and MPO-positive cells in lung tissue were also significantly reduced by FK866. Additionally, FK866 mitigated I/R-stimulated degradation of IκB-α, nuclear translocation of NF-κB, Akt phosphorylation, activation of mitogen-activated protein kinase, and downregulated MKP-1 activity in the injured lung tissue. Furthermore, FK866 increased Bcl-2 and decreased caspase-3 activity in the I/R rat lungs. Comparably, the in vitro experiments showed that FK866 also inhibited IL-8 production and NF-κB activation in human alveolar epithelial cells exposed to H/R. CONCLUSIONS: Our findings suggest that NAMPT inhibition may be a novel therapeutic approach for I/R-induced lung injury. The protective effects involve the suppression of multiple signal pathways.

Ac2-26, an Annexin A1 Peptide, Attenuates Ischemia-Reperfusion-Induced Acute Lung Injury.

Annexin A1 (AnxA1) is an endogenous protein that modulates anti-inflammatory processes, and its therapeutic potential has been reported in a range of inflammatory diseases. The effect of AnxA1 on ischemia-reperfusion (IR)-induced lung injury has not been examined. In this study, isolated, perfused rat lungs were subjected to IR lung injury induced by ischemia for 40 min, followed by reperfusion for 60 min. The rat lungs were randomly treated with vehicle (phosphate-buffered saline), and Ac2-26 (an active N-terminal peptide of AnxA1) with or without an N-formyl peptide receptor (FPR) antagonist N-Boc-Phe-Leu-Phe-Leu-Phe (Boc2). An in vitro study of the effects of Ac2-26 on human alveolar epithelial cells subjected to hypoxia-reoxygenation was also investigated. Administration of Ac2-26 in IR lung injury produced a significant attenuation of lung edema, pro-inflammatory cytokine production recovered in bronchoalveolar lavage fluid, oxidative stress, apoptosis, neutrophil infiltration, and lung tissue injury. Ac2-26 also decreased AnxA1 protein expression, inhibited the activation of nuclear factor-κB and mitogen-activated protein kinase pathways in the injured lung tissue. Finally, treatment with Boc2 abolished the protective action of Ac2-26. The results indicated that Ac2-26 had a protective effect against acute lung injury induced by IR, which may be via the activation of the FPR.

Valproic acid attenuates acute lung injury induced by ischemia-reperfusion in rats.

BACKGROUND: Evidence reveals that histone deacetylase (HDAC) inhibition has potential for the treatment of inflammatory diseases. The protective effect of HDAC inhibition involves multiple mechanisms. Heme oxygenase-1 (HO-1) is protective in lung injury as a key regulator of antioxidant response. The authors examined whether HDAC inhibition provided protection against ischemia-reperfusion (I/R) lung injury in rats by up-regulating HO-1 activity. METHODS: Acute lung injury was induced by producing 40 min of ischemia followed by 60 min of reperfusion in isolated perfused rat lungs. The rats were randomly allotted to control group, I/R group, or I/R + valproic acid (VPA) group with or without an HO-1 activity inhibitor (zinc protoporphyrin IX) (n = 6 per group). RESULTS: I/R caused significant increases in the lung edema, pulmonary arterial pressure, lung injury scores, tumor necrosis factor-α, and cytokine-induced neutrophil chemoattractant-1 concentrations in bronchoalveolar lavage fluid. Malondialdehyde levels, carbonyl contents, and myeloperoxidase-positive cells in lung tissue were also significantly increased. I/R stimulated the degradation of inhibitor of nuclear factor-κB-α, nuclear translocation of nuclear factor-κB, and up-regulation of HO-1 activity. Furthermore, I/R decreased B-cell lymphoma-2, heat shock protein 70, acetylated histone H3 protein expression, and increased the caspase-3 activity in the rat lungs. In contrast, VPA treatment significantly attenuated all the parameters of lung injury, oxidative stress, apoptosis, and inflammation. In addition, VPA treatment also enhanced HO-1 activity. Treatment with zinc protoporphyrin IX blocked the protective effect of VPA. CONCLUSIONS: VPA protected against I/R-induced lung injury. The protective mechanism may be partly due to enhanced HO-1 activity following HDAC inhibition.

Hypercapnic acidosis prolongs survival of skin allografts.

BACKGROUND: Evidence reveals that hypercapnic acidosis (HCA) modulates immune responses. However, the effect of HCA on allogenic skin graft rejection is unknown. We examined whether HCA might improve skin graft survival in a mouse model of skin transplantation. METHODS: A major histocompatibility-complex-incompatible BALB/c to C57BL/6 mouse skin transplantation model was used. Animals were divided into sham control, air, and HCA groups. Mice in the HCA group were exposed daily to 5% CO2 in air for 1 h. Skin grafts were harvested for histologic analyses. Nuclear factor (NF)-κB activation was determined in harvested draining lymph nodes. Spleen weights and serum levels of tumor necrosis factor-α and chemokine (C-X-C motif) ligand 2 were serially assessed after skin transplantation. RESULTS: Skin allografts survived significantly longer in the HCA group of mice than those in the air group. Allografted mice in the air group underwent a 2.1-fold increase in spleen weight compared with a 1.1-fold increase in the mice with HCA on day 3. There were increased inflammatory cell infiltration, folliculitis, focal dermal-epidermal separation, and areas of epidermal necrosis in the air group that were reduced with HCA treatment. In the HCA group, CD8(+) T cell infiltration at day 7 decreased significantly but not CD4(+) T cell infiltration. In addition, HCA significantly suppressed serum tumor necrosis factor-α on days 1 and 3 and chemokine (C-X-C motif) ligand 2 on days 1 and 10. Furthermore, the HCA group had remarkably suppressed NF-κB activity in draining lymph nodes. CONCLUSIONS: HCA significantly prolonged the survival of incompatible skin allografts in mice by reducing proinflammatory cytokine production, immune cell infiltration, and NF-κB activation.

Monomethyl fumarate attenuates lung Ischemia/Reperfusion injury by disrupting the GAPDH/Siah1 signaling cascade.

Monomethyl fumarate (MMF), a potent anti-inflammatory agent used to treat multiple sclerosis, has demonstrated efficacy in various inflammatory and ischemia/reperfusion (IR) models; however, its impact on IR-induced acute lung injury (ALI) has not been explored. We investigated, for the first time, whether MMF attenuates lung IR injury through inhibition of the GAPDH/Siah1 signaling pathway. Rats were subjected to IR injury using an isolated perfused lung model, and proximity ligation assays were employed to evaluate the presence and distribution of the GAPDH/Siah1 complex. In vitro studies involved pretreating human primary alveolar epithelial cells (HPAECs) with MMF and/or inducing GAPDH overexpression or silencing, followed by exposure to hypoxia-reoxygenation. The findings revealed significantly reduced lung damage indicators, including edema, proinflammatory cytokines, oxidative stress and apoptosis, in MMF-treated rats. Notably, MMF treatment inhibited GAPDH/Siah1 complex formation and nuclear translocation, indicating that disruption of the GAPDH/Siah1 cascade was the primary cause of these improvements. Our in vitro studies on pretreated HPAECs corroborate these in vivo findings, further strengthening this interpretation. Our study results suggest that the protective effects of MMF against lung IR injury may be attributed, at least in part, to its ability to disrupt the GAPDH/Siah1 signaling cascade, thereby attenuating inflammatory and apoptotic responses. Given these encouraging results, MMF has emerged as a promising therapeutic candidate for the management of lung IR injury.

Alda-1 ameliorates air embolism-induced acute lung injury.

OBJECTIVE: Evidence suggests that aldehyde dehydrogenase 2 (ALDH2) offers protection against damage caused by oxidative stress in diverse rodent models. Nonetheless, the effect of Alda-1, a compound that activates ALDH2, on acute lung injury (ALI) induced by air embolism (AE) remains unclear. The objective of this study was to explore the protective effects of Alda-1 in ALI induced by AE. METHODS: A rat model of in situ isolated perfused lung was established to investigate AE-induced ALI. Air was infused into the pulmonary artery at 0.25 mL/min for 1 minute. Before inducing AE, different doses (10, 20, or 30 mg/kg) of Alda-1 were given through intraperitoneal injection. Pathological changes in lung tissue were assessed using hematoxylin-eosin staining. We performed Western blot analysis to assess the protein levels of ALDH2,4-hydroxy-trans-2-nonenal (4-HNE), Bcl-2, caspase-3, phosphatidylinositol 3-kinase (PI3K), Akt, IκB-α, and nuclear NF-κB. RESULTS: Notably, AE results were demonstrated as harmful to the lungs, which is evidenced by intensified lung edema and disruption of lung tissue structure. Furthermore, AE caused a decrease in ALDH2 expression, increased accumulation of 4-HNE and MDA, infiltration of neutrophils, increased production of inflammatory cytokines, apoptosis, and upregulation of the PI3K/Akt and NF-κB signaling pathways within the lungs. Administration of a 20 mg/kg dose of Alda-1 alleviated the detrimental effects induced by AE. CONCLUSION: Alda-1 shows promise in mitigating AE-induced ALI, possibly through the upregulation of ALDH2 expression and suppression of the PI3K/Akt and NF-κB signaling pathways. Further research is warranted to validate these findings and to explore their translational potential in human subjects.

Hypercapnic acidosis attenuates reperfusion injury in isolated and perfused rat lungs.

OBJECTIVE: Although ischemia-reperfusion injury is a major determinant of primary graft dysfunction after lung transplantation, an approach to extend preoperative lung preservation to postoperative protection has not yet been defined. The purpose of this study was to determine the protective effects of and the signal pathway regulated by hypercapnic acidosis in ischemia-reperfusion-induced lung injury. DESIGN: Animal study. SETTING: Animal care facility procedure room in a medical center. SUBJECTS: Adult male Sprague-Dawley rats. INTERVENTIONS: Lung injury was induced in a clinically relevant ex vivo animal model. Animals were divided into a control group (FICO(2), 5%; n = 6), ischemia-reperfusion group (FICO(2), 5%; n = 6), and hypercapnic acidosis (ischemia-reperfusion + hypercapnic acidosis) group (FICO(2), 10%; n = 6). MEASUREMENTS AND MAIN RESULTS: Ischemia-reperfusion caused significant increases in alveolar lavage and perfusate tumor necrosis factor-α, inflammatory cell infiltration, lung tissue malondialdehyde, bronchoalveolar lavage fluid protein concentration and lactate dehydrogenase activity, lung weight gain, and infiltration coefficient. Ventilation with 10% CO(2) significantly suppressed the inflammatory response and attenuated lung ischemia-reperfusion injury. Our results also showed that hypercapnic acidosis significantly inhibited the ischemia-reperfusion-induced phosphorylation and nuclear translocation of nuclear factor-κB. This was associated with elevation of inhibitor of nuclear factor-κB-α level and reduced IκB kinase-ß phosphorylation, suggesting a suppression of IκB kinase and thus IκB-α activation. CONCLUSIONS: Hypercapnic acidosis may attenuate lung ischemia-reperfusion injury by suppressing the activation of the IκB kinase-nuclear factor-κB pathway.

Acetate, a gut bacterial product, ameliorates ischemia-reperfusion induced acute lung injury in rats.

Recent data suggest that short-chain fatty acids (SCFAs), the major fermentation product from gut microbial degradation of dietary fiber, have protective effects against renal ischemia-reperfusion (IR) injury, colitis, and allergic asthma. However, the effect of SCFAs on acute lung injury (ALI) caused by IR is still unclear. In this study, we examine whether SCFAs have protective effects against IR-induced ALI and explore possible protective mechanisms. IR-induced ALI was established by 40 min ischemia followed by 60 min reperfusion in isolated perfused rat lungs. Rats were randomly assigned to one of six groups: control, control + acetate (400 mg/kg), IR, and IR + acetate at one of three dosages (100, 200, 400 mg/kg). Bronchoalveolar lavage fluids (BALF) and lung tissues were obtained and analyzed at the end of the experiment. In vitro, mouse lung epithelial cells (MLE-12) subjected to hypoxia-reoxygenation (HR) were pretreated with acetate (25 mmol/L) and GPR41 or GPR43 siRNA. Acetate decreased lung weight gain, lung weight/body weight ratios, wet/dry weight ratios, pulmonary artery pressure, and protein concentration of the BALF in a dose-dependent manner for IR-induced ALI. Acetate also significantly inhibited the production of TNF-α, IL-6 and CINC-1 in the BALF. Moreover, acetate treatment restored suppressed IκB-α levels and reduced nuclear NF-κB p65 levels in lung tissues. In addition, acetate mitigated IR-induced apoptosis and tight junction disruption in injured lung tissue. In vitro analyses showed that acetate attenuated NF-κB activation and KC/CXCL-1 levels in MLE-12 cells exposed to HR. The protective effects of acetate in vitro were significantly abrogated by GPR41 or GPR43 siRNA. Acetate ameliorates IR-induced acute lung inflammation and its protective mechanism appears to be via the GPR41/43 signaling pathway. Based on our findings, acetate may provide a novel adjuvant therapeutic approach for IR-induced lung injury.

A High-Fiber Diet or Dietary Supplementation of Acetate Attenuate Hyperoxia-Induced Acute Lung Injury.

A high fiber diet (HFD) and dietary supplementation with acetate have been reported to have beneficial effects in a variety of diseases. We investigated the effects of a HFD and acetate supplementation on the gut microbiota and hyperoxia-induced acute lung injury (HALI) in mice. Mice were fed a control diet, HFD, or acetate supplementation for three weeks, and their gut microbiome composition, lung tissues, and bronchoalveolar lavage fluid (BALF) were examined after exposure to ambient air or hyperoxia. Both the HFD and acetate supplementation modified the gut microbiota community and increased the proportion of acetate-producing bacteria in mice exposed to hyperoxia. The HFD and acetate supplementation also increased the abundance of Bacteroides acidifaciens and reduced gut dysbiosis according to the ratio of Firmicutes to Bacteroidetes. Compared with hyperoxia-exposed mice fed a control diet, both the HFD and acetate supplementation significantly increased the survival time while reducing the severity of pulmonary edema and the concentrations of protein and inflammatory mediators in BALF. Moreover, the HFD and acetate supplementation reduced the production of free radicals, attenuated NF-κB signaling activation, and decreased apoptosis in the lung tissues. Overall, this study indicates that a HFD or acetate supplementation reduces the severity of HALI through alterations in the gut microbiota to exert anti-inflammatory effects.

Intermittent Exposure of Hypercapnia Suppresses Allograft Rejection via Induction of Treg Differentiation and Inhibition of Neutrophil Accumulation.

BACKGROUND: In the management of major burn wounds, allogeneic skin transplantation is a critical procedure to improve wound repair. Our previous works found that intermittent exposure to carbon dioxide leads to permissive hypercapnia (HCA) and prolongs skin allograft survival. However, the modulatory effects of HCA exposure on the immune system are not well understood. OBJECTIVES: Our purpose was to investigate how intermittent exposure to HCA can effectively reduce the immune reaction to allogeneic skin graft rejection. METHODS: A fully major histocompatibility complex-incompatible skin transplant from BALB/c to C57BL/6 mice model was utilized. Immune cells from splenic and draining lymph nodes were analyzed by flow cytometry. Serum proinflammatory cytokines were analyzed by ELISA. RESULTS: Serum levels of IFN-γ, IL-2, IL-6, and TNF-α were significantly decreased in the HCA group. Additionally, the percentage of CD8+ cells in draining lymph nodes was significantly lower in HCA than in the control group. Moreover, the generation rate of FoxP3+ regulatory T cells (Tregs) from spleen naïve CD4+ T cells was increased by intermittent exposure to carbon dioxide. The infiltrated neutrophils were also eliminated by HCA. Taken together, we concluded that intermittent hypercapnia exposure could effectively suppress skin rejection by stimulating Treg cell generation and suppressing immune reactions.

KL-6 as a Biomarker of Interstitial Lung Disease Development in Patients with Sjögren Syndrome: A Retrospective Case-Control Study.

Objective: Krebs von den Lungen-6 (KL-6) is expressed on regenerating type II pneumocytes and has been recognized as biomarkers in interstitial lung disease (ILD). We aim to identify the role of the serum KL-6 level in patients with newly diagnosed Sjögren syndrome (SS), as well as the correlation between the immunoassays. Methods: Patients with newly diagnosed SS and receiving HRCT for clinical reason during follow-up were included. Baseline KL-6 level was measured via enzyme-linked immunosorbent assay (ELISA) and latex particle-enhanced turbidimetric immunoassay (LETIA). Results: Of the 39 patients, 21 (53.85%) developed interstitial lung disease (ILD) by the conclusion of the follow-up period. The median time to diagnosis of ILD was 2.24 years (IQR 1.15-4.34) in the ILD group. The median serum KL-6 level, measured using ELISA, was 1232 U/mL (IQR 937-2242) and 764.5 U/mL (IQR 503.25-1035.75) in the ILD group and the non-ILD group, respectively (p = 0.001). The median LETIA for serum KL-6 was 329 U/mL (IQR 235-619) and 245 U/mL (IQR 215.25-291) in the ILD group and the non-ILD group, respectively (p = 0.074). Conclusion: Serum KL-6 levels were higher in newly diagnosed SS patients with ILD diagnosis during follow-up. Thus, the serum KL-6 level can serve as a valuable biomarker to identify hidden ILD in patients with newly diagnosed SS patients. However, the immunoassay procedure may influence the efficacy of the prediction and its clinical association.

Glutamine protects ischemia-reperfusion induced acute lung injury in isolated rat lungs.

Glutamine has been used to treat a number of diseases via modulating the inflammatory response. The purpose of this study is to investigate whether glutamine has a beneficial effect in ischemia-reperfusion (IR) induced acute lung injury in an isolated rat lung model. Typical acute lung injury in rats was successfully induced by 60 min of ischemia and 60 min of reperfusion. At the end of experiment, bronchoalveolar lavage fluid (BALF), perfusate and lung tissues were collected to evaluate the degree of lung injury. Glutamine (20 mM) was administrated before ischemia or after ischemia. IR caused a significant increase in the capillary filtration coefficient; lung weight gain; lung weight to body weight ratio; wet to dry weight ratio; pulmonary arterial pressure; and protein concentration and lactate dehydrogenase level in BALF. Tumor necrosis factor-α and cytokine induced neutrophil chemoattractant-1 in perfusate, and malondialdehyde levels, carbonyl content and myeloperoxidase activities in lung tissue were also significantly increased. In addition, the lung tissues showed increased septal thickness and neutrophil infiltration. Furthermore, NF-κB activity and degradation of IκB-α were significantly increased in the lungs. Treatment with glutamine before ischemia or after ischemia significantly decreased the increase in these parameters. Our study showed that glutamine treatment decreased IR-induced acute lung injury. The protective mechanism may be due to the inhibition of NF-κB activation and the attenuation of oxidative stress.

Protease-Activated Receptor-1 Antagonist Protects Against Lung Ischemia/Reperfusion Injury.

Protease-activated receptor (PAR)-1 is a thrombin-activated receptor that plays an essential role in ischemia/reperfusion (IR)-induced acute inflammation. PAR-1 antagonists have been shown to alleviate injuries in various IR models. However, the effect of PAR-1 antagonists on IR-induced acute lung injury (ALI) has not yet been elucidated. This study aimed to investigate whether PAR-1 inhibition could attenuate lung IR injury. Lung IR was induced in an isolated perfused rat lung model. Male rats were treated with the specific PAR-1 antagonist SCH530348 (vorapaxar) or vehicle, followed by ischemia for 40 min and reperfusion for 60 min. To examine the role of PAR-1 and the mechanism of SCH530348 in lung IR injury, western blotting and immunohistochemical analysis of lung tissue were performed. In vitro, mouse lung epithelial cells (MLE-12) were treated with SCH530348 or vehicle and subjected to hypoxia-reoxygenation (HR). We found that SCH530348 decreased lung edema and neutrophil infiltration, attenuated thrombin production, reduced inflammatory factors, including cytokine-induced neutrophil chemoattractant-1, interleukin-6 and tumor necrosis factor-α, mitigated lung cell apoptosis, and downregulated the phosphoinositide 3-kinase (PI3K), nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways in IR-injured lungs. In addition, SCH530348 prevented HR-induced NF-κB activation and inflammatory chemokine production in MLE12 cells. Our results demonstrate that SCH530348 exerts protective effects by blocking PAR-1 expression and modulating the downstream PI3K, NF-κB and MAPK pathways. These findings indicate that the PAR-1 antagonist protects against IR-induced ALI and is a potential therapeutic candidate for lung protection following IR injury.