Mycobacterium tuberculosis virulence protein ESAT-6 influences M1/M2 polarization and macrophage apoptosis to regulate tuberculosis progression.

BACKGROUND: Tuberculosis (TB) is an infectious disease caused by infection with Mycobacterium tuberculosis (Mtb), and it remains one of the major threats to human health worldwide. To our knowledge, the polarization of M1/M2 macrophages were critical innate immune cells which play important roles in regulating the immune response during TB progression. OBJECTIVE: We aimed to explore the potential mechanisms of M1/M2 macrophage polarization in TB development. METHODS: THP-1 macrophages were treated with early secreted antigenic target of 6 kDa (ESAT-6) protein for an increasing time. The polarization profiles, apoptosis levels of M1 and M2 macrophages were detected by RT-qPCR, immunofluorescence, Western blot and flow cytometry. RESULTS: ESAT-6 initially promoted the generation of pro-inflammatory M1-polarized macrophages in THP-1 cells within 24 h, which were suppressed by further ESAT-6 treatment at 30-42 h. Interestingly, ESAT-6 continuously promoted M2 polarization of THP-1 cells, thereby maintaining the anti-inflammatory response in a time-dependent manner. In addition, ESAT-6 promoted apoptotic cell death in M1-polarized macrophages, which had little effects on apoptosis of M2-phenotype of macrophages. Then, the potential underlying mechanisms were uncovered, and we verified that ESAT-6 increased the protein levels of TLR4, MyD88 and NF-κB to activate the TLR4/MyD88/NF-κB pathway within 24 h, and this signal pathway was significantly inactivated at 36 h post-treatment. Interestingly, the following experiments confirmed that ESAT-6 TLR4/MyD88/NF-κB pathway-dependently regulated M1/M2 polarization and apoptosis of macrophage in THP-1 cells. CONCLUSION: Our study investigated the detailed effects and mechanisms of M1/M2 macrophages in regulating innate responses during TB development, which provided a new perspective on the development of treatment strategies for this disease.

High-flow nasal cannula versus conventional oxygen therapy in acute COPD exacerbation with mild hypercapnia: a multicenter randomized controlled trial.

BACKGROUND: High-flow nasal cannula (HFNC) can improve ventilatory function in patients with acute COPD exacerbation. However, its effect on clinical outcomes remains uncertain. METHODS: This randomized controlled trial was conducted from July 2017 to December 2020 in 16 tertiary hospitals in China. Patients with acute COPD exacerbation with mild hypercapnia (pH ≥ 7.35 and arterial partial pressure of carbon dioxide > 45 mmHg) were randomly assigned to either HFNC or conventional oxygen therapy. The primary outcome was the proportion of patients who met the criteria for intubation during hospitalization. Secondary outcomes included treatment failure (intolerance and need for non-invasive or invasive ventilation), length of hospital stay, hospital cost, mortality, and readmission at day 90. RESULTS: Among 337 randomized patients (median age, 70.0 years; 280 men [83.1%]; median pH 7.399; arterial partial pressure of carbon dioxide 51 mmHg), 330 completed the trial. 4/158 patients on HFNC and 1/172 patient on conventional oxygen therapy met the criteria for intubation (P = 0.198). Patients progressed to NPPV in both groups were comparable (15 [9.5%] in the HFNC group vs. 22 [12.8%] in the conventional oxygen therapy group; P = 0.343). Compared with conventional oxygen therapy, HFNC yielded a significantly longer median length of hospital stay (9.0 [interquartile range, 7.0-13.0] vs. 8.0 [interquartile range, 7.0-11.0] days) and a higher median hospital cost (approximately $2298 [interquartile range, $1613-$3782] vs. $2005 [interquartile range, $1439-$2968]). There were no significant differences in other secondary outcomes between groups. CONCLUSIONS: In this multi-center randomized controlled study, HFNC compared to conventional oxygen therapy did not reduce need for intubation among acute COPD exacerbation patients with mild hypercapnia. The future studies should focus on patients with acute COPD exacerbation with respiratory acidosis (pH < 7.35). However, because the primary outcome rate was well below expected, the study was underpowered to show a meaningful difference between the two treatment groups. TRIAL REGISTRATION: NCT03003559 . Registered on December 28, 2016.

[The changes of vascular active substances in pulmonary embolism rats and a comparative study of anticoagulant drugs].

OBJECTIVE: To establish the rat model of acute pulmonary embolism, and study the changes of vascular active substances in pulmonary embolism rats, and investigate the interventive effect of anticoagulant drugs on vascular active substances. METHODS: One hundred and twenty-eight rats were randomly divided into four groups: control group, model group, low-molecular-weight heparin and warfarin treated group and rivaroxaban-treated group (n = 32 in each group). The method of autologous thrombosis was used to establish the animal model of acute pulmonary embolism. The animals were treated with saline or different anticoagulant drugs. The physiological and biochemical parameters were detected at different time points after embolization. The rats were killed after embolism of 24 h, 3 d, 5 d or 1 week respectively and the pathologic samples of lung tissues were collected to analyze the pulmonary pathological changes in different groups. RESULTS: Rats in embolization group after blood clots injection showed shortness of breath, oral cyanosis; quicken heart rates and other symptoms. All embolization groups had pulmonary hypertension, the levels of type B natriuretic peptide (BNP) were increased significantly. The ratio of endothelin-1 (ET-1)/NO and thromboxane (TXB2) and prostacyclin (6-k-PGFla) were abnormal. After treated with effective anticoagulant drugs, the levels of BNP, ET-1, NO, TXB2 and 6-k-PGF1a were tended to the normal levels in the control group. The pulmonary hypertensions were gradually decreased. The efficacy of rivaroxaban on pulmonary embolism was the same as that of the low molecular weight heparin or warfarin. CONCLUSION: Anticoagulation therapy can effectively improve endothelial function after pulmonary embolism, reduce pulmonary hypertension, and revise the increased BNP levels to normal levels. The efficacy of rivaroxaban is not inferior to that of low molecular weight heparin and warfarin.