Hsa_circ_0096157 silencing suppresses autophagy and reduces cisplatin resistance in non-small cell lung cancer by weakening the Nrf2/ARE signaling pathway.

BACKGROUND: Non-small cell lung cancer (NSCLC) is the leading cause of cancer morbidity and mortality worldwide, and new diagnostic markers are urgently needed. We aimed to investigate the mechanism by which hsa_circ_0096157 regulates autophagy and cisplatin (DDP) resistance in NSCLC. METHODS: A549 cells were treated with DDP (0 µg/mL or 3 µg/mL). Then, the autophagy activator rapamycin (200 nm) was applied to the A549/DDP cells. Moreover, hsa_circ_0096157 and Nrf2 were knocked down, and Nrf2 was overexpressed in A549/DDP cells. The expression of Hsa_circ_0096157, the Nrf2/ARE pathway-related factors Nrf2, HO-1, and NQO1, and the autophagy-related factors LC3, Beclin-1, and p62 was evaluated by qRT‒PCR or western blotting. Autophagosomes were detected through TEM. An MTS assay was utilized to measure cell proliferation. The associated miRNA levels were also tested by qRT‒PCR. RESULTS: DDP (3 µg/mL) promoted hsa_circ_0096157, LC3 II/I, and Beclin-1 expression and decreased p62 expression. Knocking down hsa_circ_0096157 resulted in the downregulation of LC3 II/I and Beclin-1 expression, upregulation of p62 expression, and decreased proliferation. Rapamycin reversed the effect of interfering with hsa_circ_0096157. Keap1 expression was lower, and Nrf2, HO-1, and NQO1 expression was greater in the A549/DDP group than in the A549 group. HO-1 expression was repressed after Nrf2 interference. In addition, activation of the Nrf2/ARE pathway promoted autophagy in A549/DDP cells. Moreover, hsa_circ_0096157 activated the Nrf2/ARE pathway. The silencing of hsa_circ_0096157 reduced Nrf2 expression by releasing miR-142-5p or miR-548n. Finally, we found that hsa_circ_0096157 promoted A549/DDP cell autophagy by activating the Nrf2/ARE pathway. CONCLUSION: Knockdown of hsa_circ_0096157 inhibits autophagy and DDP resistance in NSCLC cells by downregulating the Nrf2/ARE signaling pathway.

Differential Proteomic and Genomic Comparison of Resistance Mechanism of Pseudomonas aeruginosa to Cefoperazone Sodium/Sulbactam Sodium.

The aim of this study was to determine the resistance mechanism of Pseudomonas aeruginosa to cefoperazone sodium/sulbactam sodium. We retrospectively analyzed the drug resistance of P.a isolated at the First Affiliated Hospital of Guangxi Medical University. Drug-resistant P.a strains were constructed, then wild-type (WT) and drug-resistant (DR) strains were compared using protein and gene microarrays to determine differences between DR and WT strains. The resistance rates of P. aeruginosa during 2013, 2014 and 2015 were 21.2%, 21.4%, and 24.6% respectively. Among 242 protein peaks of WT and DR bacteriophage proteins, 41 were differentially expressed between the two groups. The expression of 26 and 15 proteins were respectively upregulated and downregulated in the DR compared with the WT group. Gene microarray results revealed 679 mutant loci in the DR group, of which 42 with the top 50 Q values were found in the NCBI database. The rate of P.a resistance to cefoperazone sodium/sulbactam sodium remained high between 2013 and 2015. The numbers of different proteins and genetic variations in the DR strains suggested that the resistance mechanism of P.a to cefoperazone sodium/sulbactam sodium involves multiple genes and proteins that might be key to controlling P.a resistance to cefoperazone sodium/sulbactam sodium.

Clinical significance of circPVT1 in patients with non-small cell lung cancer who received cisplatin combined with gemcitabine chemotherapy.

OBJECTIVE: CircPVT1 was identified as a tumor-promoted circRNA that is upregulated in several cancers. We researched clinical significance of circPVT1 in patients with non-small cell lung cancer (NSCLC) who received cisplatin combined with gemcitabine chemotherapy. METHODS: Reverse transcriptase polymerase chain reaction assays were performed to detect circPVT1 expression in 96 patients with NSCLC. In addition, Kaplan-Meier methods were performed to analyze survival of patients with NSCLC. RESULTS: There is no significant difference between circPVT1 and age, sex, histologic type, lymphatic invasion, or vascular invasion in patients with NSCLC and there is significant difference between circPVT1 and differentiation or p-TNM stage in patients with NSCLC. In addition, after cisplatin combined with gemcitabine chemotherapy, circPVT1 expression was decreased, and circPVT1 expression in the chemotherapy-resistant group was higher than in the chemotherapy-sensitive group. Survival of patients with NSCLC was associated with high circPVT1 expression. CONCLUSIONS: Our study revealed the clinical significance of circPVT1 in NSCLC after cisplatin combined with gemcitabine chemotherapy. After treatment, circPVT1 expression was decreased and circPVT1 expression in chemotherapy-resistant patients was higher than in chemotherapy-sensitive patients. Decreased circPVT1 expression in chemotherapy-sensitive patients is more notable than in chemotherapy-resistant patients. Therefore, it is possible to determine the effect of therapy after receiving chemotherapy by detecting the expression of circRNA in serum.

Circular RNA hsa_circ_0096157 contributes to cisplatin resistance by proliferation, cell cycle progression, and suppressing apoptosis of non-small-cell lung carcinoma cells.

Circular RNAs (circRNAs) play a major role in cancer development and chemotherapy resistance. This study aimed to characterize circRNA profiles associated with Cisplatin (diamminedichloroplatinum, DDP) resistance of non-small-cell lung carcinoma (NSCLC) cells. The half-maximal inhibitory concentration (IC50) of A549 and A549/DDP cells was determined using CCK-8 assay. Further, circRNA profiles and differentially expressed genes in A549 and A549/DDP cells were characterized by deep sequencing and cell proliferation was measured using MTS assay. Cell cycle progression was analyzed using flow cytometry. Apoptosis experiment was performed by TUNEL assay and flow cytometry. Cell migration and invasion were assessed using the Transwell system. Finally, signalling protein levels related to cell cycle progression and migration were measured by western blot. CCK-8 assay showed that A549/DDP cells obtained strong DDP resistance. Further deep sequencing results showed that 689 circRNAs and 87 circRNAs were significantly upregulated and downregulated in A549/DDP cells compared to A549 cells, respectively. Moreover, the circRNA hsa_circ_0096157 with the highest expression level in A549/DPP cells was further analyzed for its potential mechanism of DDP resistance in A549/DDP. With or without DDP treatment, hsa_circ_0096157 knockdown inhibited proliferation, migration, invasion and cell cycle progression but promoted apoptosis of A549/DDP cells. In addition, the western blot results also showed that hsa_circ_0096157 knockdown in A549/DDP cells increased P21 and E-cadherin but decreased CDK4, Cyclin D1, Bcl-2, N-cadherin, and Vimentin protein expression levels, indicating that cell cycle progression might be inhibited by increased P21 protein level to inhibit the expression of CDK4-cyclin D1 complex and decreased Bcl-2 protein level; and migration and invasion were suppressed by the increased E-cadherin and decreased N-cadherin and Vimentin expression levels. In contrast, hsa_circ_0096157 overexpression in A549 cells caused the opposite cellular and molecular alterations. DDP resistance in NSCLC cells was associated with significant circRNA profile alterations. Moreover, increased hsa_circ_0096157 expression contributed to DDP resistance in NSCLC cells by promoting cell proliferation, migration, invasion and cell cycle progression and inhibiting apoptosis.

The miRNA-149-5p/MyD88 axis is responsible for ursolic acid-mediated attenuation of the stemness and chemoresistance of non-small cell lung cancer cells.

Although the inhibitory roles of ursolic acid (UA) have been established in various tumors, its effects on the stemness of non-small cell lung cancer (NSCLC) cells are still unclear. Here, we constructed NSCLC cells with paclitaxel resistance (A549-PR) and showed that A549-PR exhibited a remarkably stronger stemness than the parental A549 cells, which is evident by the increase of spheroid formation capacity, stemness marker expression, and ALDH1 activity. Additionally, UA significantly reduced the stemness and paclitaxel resistance of A549-PR cells. Mechanistic investigations revealed that UA inhibited the miR-149-5p/MyD88 signaling, which is responsible for UA-mediated effects on the stemness of A549-PR cells. Notably, miR-149-5p/MyD88 axis promoted the stemness of A549 cells, while inhibition of this axis attenuated the stemness of A549-PR cells. Therefore, these results suggest that UA could attenuate the stemness and chemoresistance of NSCLC cells through targeting miR-149-5p/MyD88 axis.

Septic pulmonary embolism in China: clinical features and analysis of prognostic factors for mortality in 98 cases.

BACKGROUND: To investigate the clinical features of septic pulmonary embolism (SPE) cases and prognostic factors for in-hospital mortality in China. METHODS: A retrospective analysis was conducted of SPE patients hospitalized between January 2007 and June 2018 in the Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Guangxi Medical University. RESULTS: A total of 98 patients with SPE were identified. All patients had bilateral multiple peripheral nodules on chest computed tomography. The most common pathogen found in blood culture was Staphylococcus aureus (10/33, 30.3%). Transthoracic echocardiography was performed in 39 patients and 20 showed vegetations. Bronchoscopy was performed in 24 patients. Bronchoalveolar lavage fluid (BALF) was obtained from 15 patients (62.5%) and showed predominantly polymorphonuclear cell infiltration (52%, range of 48%~ 63%). Four patients received transbronchial lung biopsy, and histopathological examinations revealed suppurative pneumonia and organizing pneumonia. The in-hospital mortality rate was 19.4%. Age (odds ratio [OR] 1.100; 95% confidence interval [CI] 1.035-1.169), hypotension (OR 7.260; 95% CI 1.126-46.804) and ineffective or delay of empirical antimicrobial therapy (OR 7.341; 95% CI 1.145-47.045) were found to be independent risk factors for in-hospital mortality, whereas drainage treatment was found to be a protective factor (OR 0.33; 95% CI 0.002-0.677). CONCLUSIONS: SPE cases presented with nonspecific clinical manifestations and radiologic features. Blood cultures and bronchoscopy are important measures for early diagnosis and differential diagnosis. There is relationship between primary infection sites and the type of pathogen. Maintaining normal blood pressure and providing timely and appropriate initial antimicrobial therapy for effective control of the infection could improve prognosis.

The rapid in vivo evolution of Pseudomonas aeruginosa in ventilator-associated pneumonia patients leads to attenuated virulence.

Pseudomonas aeruginosa is an opportunistic pathogen that causes severe airway infections in humans. These infections are usually difficult to treat and associated with high mortality rates. While colonizing the human airways, P. aeruginosa could accumulate genetic mutations that often lead to its better adaptability to the host environment. Understanding these evolutionary traits may provide important clues for the development of effective therapies to treat P. aeruginosa infections. In this study, 25 P. aeruginosa isolates were longitudinally sampled from the airways of four ventilator-associated pneumonia (VAP) patients. Pacbio and Illumina sequencing were used to analyse the in vivo evolutionary trajectories of these isolates. Our analysis showed that positive selection dominantly shaped P. aeruginosa genomes during VAP infections and led to three convergent evolution events, including loss-of-function mutations of lasR and mpl, and a pyoverdine-deficient phenotype. Specifically, lasR encodes one of the major transcriptional regulators in quorum sensing, whereas mpl encodes an enzyme responsible for recycling cell wall peptidoglycan. We also found that P. aeruginosa isolated at late stages of VAP infections produce less elastase and are less virulent in vivo than their earlier isolated counterparts, suggesting the short-term in vivo evolution of P. aeruginosa leads to attenuated virulence.

Baicalin inhibits biofilm formation, attenuates the quorum sensing-controlled virulence and enhances Pseudomonas aeruginosa clearance in a mouse peritoneal implant infection model.

The quorum sensing (QS) circuit plays a role in the precise regulation of genes controlling virulence factors and biofilm formation in Pseudomonas aeruginosa. QS-controlled biofilm formation by Pseudomonas aeruginosa in clinical settings has remained controversial due to emerging drug resistance; therefore, screening diverse compounds for anti-biofilm or anti-QS activities is important. This study demonstrates the ability of sub-minimum inhibitory concentrations (sub-MICs) of baicalin, an active natural compound extracted from the traditional Chinese medicinal Scutellaria baicalensis, to inhibit the formation of Pseudomonas aeruginosa biofilms and enhance the bactericidal effects of various conventional antibiotics in vitro. In addition, baicalin exerted dose-dependent inhibitory effects on virulence phenotypes (LasA protease, LasB elastase, pyocyanin, rhamnolipid, motilities and exotoxin A) regulated by QS in Pseudomonas aeruginosa. Moreover, the expression levels of QS-regulatory genes, including lasI, lasR, rhlI, rhlR, pqsR and pqsA, were repressed after sub-MIC baicalin treatment, resulting in significant decreases in the QS signaling molecules 3-oxo-C12-HSL and C4-HSL, confirming the ability of baicalin-mediated QS inhibition to alter gene and protein expression. In vivo experiments indicated that baicalin treatment reduces Pseudomonas aeruginosa pathogenicity in Caenorhabditis elegans. Greater worm survival in the baicalin-treated group manifested as an increase in the LT50 from 24 to 96 h. In a mouse peritoneal implant infection model, baicalin treatment enhanced the clearance of Pseudomonas aeruginosa from the implants of mice infected with Pseudomonas aeruginosa compared with the control group. Moreover, the combination of baicalin and antibiotics significantly reduced the numbers of colony-forming units in the implants to a significantly greater degree than antibiotic treatment alone. Pathological and histological analyses revealed mitigation of the inflammatory response and reduced cell infiltration in the peritoneal tissue surrounding the implants after baicalin treatment. Measurement of the cytokine levels in the peritoneal lavage fluid of mice in the baicalin treatment group revealed a decrease in IL-4, an increase in interferon γ (IFN-γ), and a reversed IFN-γ/IL-4 ratio compared with the control group, indicating that baicalin treatment activated the Th1-induced immune response to expedite bacterial load clearance. Based on these results, baicalin might be a potent QS inhibitor and anti-biofilm agent for combating Pseudomonas aeruginosa biofilm-related infections.

Administration of Voriconazole in Disseminated Talaromyces (Penicillium) Marneffei Infection: A Retrospective Study.

Talaromyces (Penicillium) marneffei infection is a fatal disseminated mycosis caused by the dimorphic fungus Talaromyces marneffei; the therapeutic strategies for this infectious disease are limited. The aim of this retrospective study was to evaluate the efficacy and safety of voriconazole for treating patients with disseminated T. marneffei infection with or without HIV infection in a clinical setting. Patients who intravenously received voriconazole (6 mg/kg q12 h for the first 24 h followed by 4 mg/kg q12 h) as the initial antifungal treatment were enrolled. The duration of the following antifungal treatment varied at the discretion of the investigators according to the patient responses. The primary global response was evaluated at Week 16 or at the end of treatment (EOT). Follow-up evaluations were performed at 6 months and 1 year after the EOT. Seventeen patients were enrolled in this study, but three were not evaluable because the treatment was prematurely discontinued. Among the remaining fourteen patients, ten patients had complete response and three had partial response at Week 16. Only one patient was determined to have failed response. Follow-up assessments in eleven patients showed that eight patients were cured and the remaining three patients relapsed at 6 months after the EOT. These eight patients were assessed 1 year later, and none of them had relapsed. No adverse events associated with voriconazole were recorded during the treatment. The results from our study suggest that voriconazole is an effective, well-tolerated therapeutic option for disseminated T. marneffei infection.

Pathogenic Effects of Biofilm on Pseudomonas Aeruginosa Pulmonary Infection and Its Relationship to Cytokines.

BACKGROUND An animal (Sprague-Dawley rat) model of Pseudomonas aeruginosa biofilm associated with chronic pulmonary infection in vivo was established and the effects of the biofilm on P. aeruginosa and its relationship to cytokines were investigated. MATERIAL AND METHODS Biofilm of P. aeruginosa in alginate beads and planktonic PA0725 were purified by anion-exchange chromatograph. Sprague-Dawley (SD) rats were immunized with the biofilm and then inhaled the same strain of P. aeruginosa. Anti-biofilm antibody titer was detected using the enzyme linked immunosorbent assay (ELISA) method. The cell count and differential count in the bronchoalveolar lavage fluid (BALF) were measured. The levels of cytokines (IL-17, IL-1ß, MIP-2, and G-CSF) and tumor necrosis factor (TNF)-α in sera were also measured using an ELISA kit. RESULTS The sera anti-biofilm IgG antibody titer of immunized SD rats was increased significantly on the 5th and 8th days after inhalation. The IL-17 concentration was significantly higher on the 8th day after inhalation. The results indicated that when biofilm-pre-immunized rats were challenged with inhalation of PA0725 of P. aeruginosa, the biofilm acted as an antigen substance and mediated the antibody reaction of the antigen, which might cause serious airway inflammatory response and lung tissue injury. This effect may be related to IL-17. CONCLUSIONS P. aeruginosa biofilm protected the bacterium from antibiotics and might induce host immune damage in lung tissue and facilitate bacterium evading the host barrier.

Study on the resistance mechanism via outer membrane protein OprD2 and metal ß-lactamase expression in the cell wall of Pseudomonas aeruginosa.

The aim of the present study was to evaluate the imipenem-resistant mechanism via the outer membrane protein (OMP) OprD2 and metal ß-lactamase expression in the cell wall of Pseudomonas aeruginosa. The Pseudomonas aeruginosa was clinically separated and validated by VITEK-2 full-automatic bacteria analyzer. Drug resistance, sensitive antibiotics and minimum inhibitory concentration (MIC) were tested using the drug sensitivity analysis system. The phenotype positive strains of MBL genes were screened using the Kirby-Bauer diffusion method by adding metal ion-chelating agent EDTA on the imipenem susceptibility paper. IMP-1, VIM-1 and SPM metaloenzyme genes were tested by polymerase chain reaction (PCR)-telomeric repeat amplification protocol (TRAP). The OMP OprD2 genes were tested by PCR-TRAP, and the protein expression was tested using western blot analysis. The location of OMP OprD2 was confirmed using the sodium salicylate inhibition test. The results showed that 80 portions (40%) of MBL-positive strains were screened out of 200 specimens. Imipenem-resistant Pseudomonas aeruginosa (IRPA) and MIC values were significantly higher than quality control bacteria and control bacteria (P<0.05). A total of 35 cases with IMP-1 positive, 20 with VIM-1 positive, 16 with SPM positive, 5 with 2 positive genes and 4 with 3 positive genes were screened among MBL positive strains. A total of 150 portions (75%) of OprD2 deficiencies were screened from 200 specimens. The standard strains and sensitive strains showed OprD2 protein bands at 45 kDa while no OprD2 protein bands appeared in OprD2 deficiency strains. It was in accordance with gene detection. In conclusion, OMP OprD2 deficiency and MBL phenotype positivity may be important mechanisms of IRPA.

Prognostic Value of Pleural Lavage Cytology in Patients with Lung Cancer Resection: An Updated Meta-Analysis.

OBJECTIVE: Pleural lavage cytology (PLC) is considered as a possible tool for assessing prognosis of lung cancer patients. We aimed to comprehensively review the prognosis value of PLC in patients undergoing surgical resection. METHODS: We searched 4 electronic databases for relevant studies comparing positive PLC and negative PLC. The primary outcomes included survival rate and recurrence rate at maximum follow-up. RESULTS: The meta-analysis included 28 studies, with a total of 20,714 patients. For the overall survival rate of all stages, the results demonstrated that positive pre-resection, post-resection and pooled PLC were associated with unfavorable survival: hazard ratio (HR) 2.89 (95% confidence interval [CI] 2.48-3.37), 2.70 (1.90-3.83), and 2.89 (2.52-3.31), respectively. For the stage I survival rate, the combined results also suggested that positive pre-resection, post-resection and pooled PLC were associated with unfavorable survival: HR 3.29 (95% CI 2.55-4.25), 4.85 (2.31-10.20), and 3.16 (2.53-3.94), respectively. Furthermore, a meta-analysis of 14 studies included 14,279 patients showed that positive pre-resection, post-resection and pooled PLC were associated with an increased risk of overall recurrence: risk ratio (RR) 2.45 (95% CI 1.91-3.15), 2.37 (1.11-5.09), and 2.37 (95% CI 2.00-2.80), respectively. Positive PLC was also associated with a high pleural recurrence (RR 4.77; 95% CI 3.13-7.26) or distant recurrence (RR 2.33; 95% CI 1.65-3.29). CONCLUSIONS: Both positive pre- resection and post-resection PLC are associated with not only higher tumor recurrence but also unfavorable survival outcomes in patients with lung cancer resection. This technique can therefore act as a strong prognostic factor for tumor recurrence and adverse survival rates.

Baicalein Inhibits Staphylococcus aureus Biofilm Formation and the Quorum Sensing System In Vitro.

Biofilm formed by Staphylococcus aureus significantly enhances antibiotic resistance by inhibiting the penetration of antibiotics, resulting in an increasingly serious situation. This study aimed to assess whether baicalein can prevent Staphylococcus aureus biofilm formation and whether it may have synergistic bactericidal effects with antibiotics in vitro. To do this, we used a clinically isolated strain of Staphylococcus aureus 17546 (t037) for biofilm formation. Virulence factors were detected following treatment with baicalein, and the molecular mechanism of its antibiofilm activity was studied. Plate counting, crystal violet staining, and fluorescence microscopy revealed that 32 µg/mL and 64 µg/mL baicalein clearly inhibited 3- and 7-day biofilm formation in vitro. Moreover, colony forming unit count, confocal laser scanning microscopy, and scanning electron microscopy showed that vancomycin (VCM) and baicalein generally enhanced destruction of biofilms, while VCM alone did not. Western blotting and real-time quantitative polymerase chain reaction analyses (RTQ-PCR) confirmed that baicalein treatment reduced staphylococcal enterotoxin A (SEA) and α-hemolysin (hla) levels. Most strikingly, real-time qualitative polymerase chain reaction data demonstrated that 32 µg/mL and 64 µg/mL baicalein downregulated the quorum-sensing system regulators agrA, RNAIII, and sarA, and gene expression of ica, but 16 µg/mL baicalein had no effect. In summary, baicalein inhibited Staphylococcus aureus biofilm formation, destroyed biofilms, increased the permeability of vancomycin, reduced the production of staphylococcal enterotoxin A and α-hemolysin, and inhibited the quorum sensing system. These results support baicalein as a novel drug candidate and an effective treatment strategy for Staphylococcus aureus biofilm-associated infections.

Mechanisms of Protective Effect of Ramulus Mori Polysaccharides on Renal Injury in High-Fat Diet/Streptozotocin-Induced Diabetic Rats.

BACKGROUND: Diabetic nephropathy (DN) is the most important complication of diabetes and the most common cause of end-stage renal disease (ESRD). AIMS: A recent study established that the Ramulus mori polysaccharides (RMP) exert antioxidant effects on DN in rats. METHODS: The diabetic rats which induced by high-fat diet and streptozotocin injection were orally administered RMP by doses of 250, 500 and 1000 mg/kg daily for 8 weeks. The effects of RMP on hyperglycemia and other biochemical changes were examined in the sera and kidney tissues. Additionally, the pathological and ultrastructural changes and expressions of nuclear-factor kappa B (NF-x03BA;B) and transforming growth factor-ß1 (TGF-ß1) were assessed. RESULTS: The results revealed that the serum levels of blood glucose, total cholesterol (TC) and triglycerides (TG) were significantly decreased by RMP. Furthermore, the blood urea nitrogen (BUN), serum creatinine (SCr) and 24-hour urine protein levels in the RMP-medicated rats were lower than those in untreated diabetic rats. Moreover, treatment of the DN rats with RMP normalized all biochemical changes, including the malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels in the serum and kidney tissues. In contrast, the protein expression levels of NF-x03BA;B and TGF-ß1, which were enhanced in the kidneys of DN rats, were reduced by RMP. CONCLUSION: These results suggest that RMP improving the renal function of diabeitc rats possibly via its ameliorating antioxidant activities.

The effect of pleural abrasion on the treatment of primary spontaneous pneumothorax: a systematic review of randomized controlled trials.

BACKGROUND: Pleural abrasion has been widely used to control the recurrence of primary spontaneous pneumothorax (PSP). However, controversy still exists regarding the advantages and disadvantages of pleural abrasion compared with other interventions in preventing the recurrence of PSP. METHODS: The PubMed, Embase, and Cochrane Central Register of Controlled Trials databases were searched up to December 15, 2014 to identify randomized controlled trials (RCTs) that compared the effects of pleural abrasion with those of other interventions in the treatment of PSP. The study outcomes included the PSP recurrence rate and the occurrence rate of adverse effects. RESULTS: Mechanical pleural abrasion and apical pleurectomy after thoracoscopic stapled bullectomy exhibited similarly persistent postoperative air leak occurrence rates (p = 0.978) and 1-year PSP recurrence rates (p = 0.821), whereas pleural abrasion led to reduced residual chest pain and discomfort (p = 0.001) and a smaller rate of hemothorax (p = 0.036) than did apical pleurectomy. However, the addition of minocycline pleurodesis to pleural abrasion did not reduce the pneumothorax recurrence rate compared with apical pleurectomy (3.8% for both procedures) but was associated with fewer complications. There was no statistical difference in the pneumothorax recurrence rate between mechanical pleural abrasion and chemical pleurodesis with minocycline on either an intention-to-treat basis (4 of 42 versus 0 of 42, p = 0.12; Fisher exact test) or after exclusions (2 of 40 versus 0 of 42, p = 0.24; Fisher exact test). Pleural abrasion plus minocycline pleurodesis also did not reduce the pneumothorax recurrence rate compared with pleural abrasion alone (p = 0.055). Moreover, pleural abrasion plus minocycline pleurodesis was associated with more intense acute chest pain. The postoperative overall recurrence rate in patients who underwent staple line coverage with absorbable cellulose mesh and fibrin glue was similar to that with mechanical abrasion after thoracoscopic bullectomy (13.8% vs. 14.2%, respectively; p = 0.555), but staple line coverage resulted in less postoperative residual pain than mechanical abrasion (0.4% vs.3.2%; p<0.0001). Pleural abrasion after thoracoscopic wedge resection did not decrease the recurrence of pneumothorax compared with wedge resection alone (p = 0.791), but the intraoperative bleeding and postoperative pleural drainage rates were higher when pleural abrasion was performed. CONCLUSIONS: In addition to resulting in the same pneumothorax recurrence rate, thoracoscopic pleural abrasion with or without minocycline pleurodesis is safer than apical pleurectomy in the treatment of PSP. However, minocycline pleurodesis with or without pleural abrasion is not any more effective than pleural abrasion alone. Moreover, additional mechanical abrasion is not safer than additional staple line coverage with absorbable cellulose mesh and fibrin glue after thoracoscopic bullectomy because of increased postoperative pain. Additionally, pleural abrasion after thoracoscopic wedge resection should not be recommended for routine application due to the greater incidence of adverse effects than wedge resection alone. However, further large-scale, well-designed RCTs are needed to confirm the best procedure.