Quantitative Histogram Analysis of T2-Weighted and Diffusion-Weighted Magnetic Resonance Images for Prediction of Malignant Thymic Epithelial Tumors.

PURPOSE: To assess the value of histogram analysis for differentiating a high-risk thymic epithelial tumor (TET) from a low-risk TET using T2-weighted images and the apparent diffusion coefficient (ADC). METHODS: Forty-nine patients with histopathologically proven TET after thymectomy were enrolled in this study and retrospectively classified as having low-risk TET (low-risk thymoma) or high-risk TET (high-risk thymoma or thymic carcinoma). Twelve parameters were obtained from the quantitative histogram analysis. The histogram parameters were compared using the Mann-Whitney U test. Diagnostic efficacy was estimated by receiver-operating characteristic curve analysis. RESULTS: Twenty-five patients were classified as having low-risk TET and 24 as having high-risk TET. The mean ADC value showed diagnostic efficacy for differentiating high-risk TET from low-risk TET, with an area under the curve of 0.7, and was better than when using conventional methods alone. CONCLUSION: The ADC-based histogram analysis could help to differentiate between high-risk and low-risk TETs.

Simultaneous Two-Dimensional and Three-Dimensional Simulation of Thoracoscopic Sleeve Lobectomy: A Quick Understanding of Pitfalls.

Thoracoscopic sleeve lobectomy is challenging, considering the technical difficulty in controlling the needle angle and thread through the port. However, effective simulation of the procedure remains to be established. Here, we describe our first experience with thoracoscopic sleeve lobectomy simulation using a three-dimensional printed thoracic model and a handmade rolled sponge. Owing to the transparent structure, we could simultaneously confirm the suturing technique through the monitor (two-dimensional) and direct vision (three-dimensional). We are certain that our realistic and easily repeatable simulation will assist in developing better technique and conduct feasible thoracoscopic sleeve lobectomy.

Recovery of pulmonary function after lung wedge resection.

BACKGROUND: Pulmonary function following lung wedge resection is not fully understood. This study aimed to assess the influence of wedge resection upon postoperative pulmonary function. METHODS: We retrospectively evaluated pulmonary function at 3, 6, and 12 months postoperatively in 29 patients who underwent lung wedge resection. The values of the pulmonary function tests (PFTs) were compared among the time points using a paired t-test. RESULTS: The vital capacity (VC) values before surgery and at 3, 6 and 12 months postoperatively were 2,994±793, 2,845±799, 2,941±801, and 2,964±839 mL, respectively. The VC decreased at 3 months postoperatively (P=0.002) and recovered by 6 and 12 months postoperatively (P=0.003 and 0.003, respectively). The VC values at 6 and 12 months postoperatively did not significantly differ from that before surgery (P=0.152 and 0.361, respectively). The forced expiratory volume in one second (FEV1) values before surgery and at 3, 6, and 12 months postoperatively were 2,156±661, 2,034±660, 2,091±672 and 2,100±666 mL, respectively. The values decreased at 3 months postoperatively (P<0.001) and recovered; however, they remained lower than the preoperative value (P=0.036). CONCLUSIONS: The postoperative VC decreased temporarily but recovered to near the preoperative level after 12 months. We concluded that the loss of VC following lung wedge resection is minimal. These findings are beneficial for planning surgery and explaining the procedure to patients who are undergoing lung wedge resection.

Involvement of GPx4-Regulated Lipid Peroxidation in Idiopathic Pulmonary Fibrosis Pathogenesis.

The imbalanced redox status in lung has been widely implicated in idiopathic pulmonary fibrosis (IPF) pathogenesis. To regulate redox status, hydrogen peroxide must be adequately reduced to water by glutathione peroxidases (GPx). Among GPx isoforms, GPx4 is a unique antioxidant enzyme that can directly reduce phospholipid hydroperoxide. Increased lipid peroxidation products have been demonstrated in IPF lungs, suggesting the participation of imbalanced lipid peroxidation in IPF pathogenesis, which can be modulated by GPx4. In this study, we sought to examine the involvement of GPx4-modulated lipid peroxidation in regulating TGF-ß-induced myofibroblast differentiation. Bleomycin-induced lung fibrosis development in mouse models with genetic manipulation of GPx4 were examined. Immunohistochemical evaluations for GPx4 and lipid peroxidation were performed in IPF lung tissues. Immunohistochemical evaluations showed reduced GPx4 expression levels accompanied by increased 4-hydroxy-2-nonenal in fibroblastic focus in IPF lungs. TGF-ß-induced myofibroblast differentiation was enhanced by GPx4 knockdown with concomitantly enhanced lipid peroxidation and SMAD2/SMAD3 signaling. Heterozygous GPx4-deficient mice showed enhancement of bleomycin-induced lung fibrosis, which was attenuated in GPx4-transgenic mice in association with lipid peroxidation and SMAD signaling. Regulating lipid peroxidation by Trolox showed efficient attenuation of bleomycin-induced lung fibrosis development. These findings suggest that increased lipid peroxidation resulting from reduced GPx4 expression levels may be causally associated with lung fibrosis development through enhanced TGF-ß signaling linked to myofibroblast accumulation of fibroblastic focus formation during IPF pathogenesis. It is likely that regulating lipid peroxidation caused by reduced GPx4 can be a promising target for an antifibrotic modality of treatment for IPF.

Risk factors and cancer recurrence associated with postoperative complications after thoracoscopic lobectomy for clinical stage I non-small cell lung cancer.

BACKGROUND: Minimally invasive thoracoscopic lobectomy is the recommended surgery for clinical stage I non-small cell lung cancer (NSCLC). The purpose of this study was to identify the risk factors, including sarcopenia, for postoperative complications in patients undergoing a complete single-lobe thoracoscopic lobectomy for clinical stage I NSCLC, as well as the impact of complications on disease-free survival. METHODS: We retrospectively investigated 173 patients with pathologically-diagnosed NSCLC who underwent curative thoracoscopic lobectomies between April 2013 and March 2018. Sarcopenia was assessed using the psoas muscle index calculated from preoperative computed tomography images at the third lumbar vertebral level. RESULTS: Complications developed in 38 (22%) patients, including 21 with prolonged air leak. In univariate analysis, the significant risk factors for complications were advanced age, male sex, higher Charlson Comorbidity Index (CCI) score, lower cholinesterase, lower albumin, higher creatinine level, pleural adhesion, operative time ≥ five hours, nonadenocarcinoma cancer, and larger tumor size. Multivariate analysis showed that age ≥ 75 years (P = 0.002) and pleural adhesion (P = 0.026) were significant independent risk factors for complications. Compared with the patient group without complications, postoperative complications were independently associated with shorter disease-free survival (P = 0.01). CONCLUSIONS: Advanced age and pleural adhesion were independent risk factors for complications after complete single-lobe thoracoscopic lobectomies for clinical stage I NSCLC, and postoperative complications were statistically associated with poor prognosis. Surgical teams should ensure an experienced surgeon leads the operation for patients at higher risk to avoid prolonged postoperative hospitalization and a possible poor prognosis.

Involvement of cigarette smoke-induced epithelial cell ferroptosis in COPD pathogenesis.

Ferroptosis is a necrotic form of regulated cell death (RCD) mediated by phospholipid peroxidation in association with free iron-mediated Fenton reactions. Disrupted iron homeostasis resulting in excessive oxidative stress has been implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). Here, we demonstrate the involvement of ferroptosis in COPD pathogenesis. Our in vivo and in vitro models show labile iron accumulation and enhanced lipid peroxidation with concomitant non-apoptotic cell death during cigarette smoke (CS) exposure, which are negatively regulated by GPx4 activity. Treatment with deferoxamine and ferrostatin-1, in addition to GPx4 knockdown, illuminate the role of ferroptosis in CS-treated lung epithelial cells. NCOA4-mediated ferritin selective autophagy (ferritinophagy) is initiated during ferritin degradation in response to CS treatment. CS exposure models, using both GPx4-deficient and overexpressing mice, clarify the pivotal role of GPx4-regulated cell death during COPD. These findings support a role for cigarette smoke-induced ferroptosis in the pathogenesis of COPD.

Risk factors for recurrence of primary spontaneous pneumothorax after thoracoscopic surgery.

BACKGROUND: Recurrence of pneumothorax after thoracoscopic surgery is a concerning issue for thoracic surgeons. In this study, we aimed to determine the risk factors for recurrence of spontaneous pneumothorax after thoracoscopic surgery. METHODS: A total of 192 patients with spontaneous pneumothorax aged <50 years who underwent thoracoscopic surgery from January 2010 to December 2016 were included in this study. Pre- and post-operative characteristics were obtained from medical records, and recurrent and non-recurrent cases were compared. RESULTS: Fourteen patients (7.3%) experienced pneumothorax recurrence. Pneumothorax recurrence was observed more frequently in patients aged <20 years (P=0.041) and those in whom bullae were not identified on preoperative computed tomography (CT) (P=0.049). The use of polyglycolic acid (PGA) sheets during surgery significantly decreased the recurrence rate (P=0.031). A history of ipsilateral pneumothorax before surgery was a significant risk factor for recurrence after thoracoscopic surgery (P=0.001). In the multivariate analysis, a history of ipsilateral pneumothorax and identification of bullae on CT were identified as significant risk factors for recurrence. CONCLUSIONS: A history of ipsilateral pneumothorax, and inability to identify bullae on preoperative CT were risk factors for postoperative recurrence of pneumothorax.

Involvement of Lamin B1 Reduction in Accelerated Cellular Senescence during Chronic Obstructive Pulmonary Disease Pathogenesis.

Downregulation of lamin B1 has been recognized as a crucial step for development of full senescence. Accelerated cellular senescence linked to mechanistic target of rapamycin kinase (MTOR) signaling and accumulation of mitochondrial damage has been implicated in chronic obstructive pulmonary disease (COPD) pathogenesis. We hypothesized that lamin B1 protein levels are reduced in COPD lungs, contributing to the process of cigarette smoke (CS)-induced cellular senescence via dysregulation of MTOR and mitochondrial integrity. To illuminate the role of lamin B1 in COPD pathogenesis, lamin B1 protein levels, MTOR activation, mitochondrial mass, and cellular senescence were evaluated in CS extract (CSE)-treated human bronchial epithelial cells (HBEC), CS-exposed mice, and COPD lungs. We showed that lamin B1 was reduced by exposure to CSE and that autophagy was responsible for lamin B1 degradation in HBEC. Lamin B1 reduction was linked to MTOR activation through DEP domain-containing MTOR-interacting protein (DEPTOR) downregulation, resulting in accelerated cellular senescence. Aberrant MTOR activation was associated with increased mitochondrial mass, which can be attributed to peroxisome proliferator-activated receptor γ coactivator-1ß-mediated mitochondrial biogenesis. CS-exposed mouse lungs and COPD lungs also showed reduced lamin B1 and DEPTOR protein levels, along with MTOR activation accompanied by increased mitochondrial mass and cellular senescence. Antidiabetic metformin prevented CSE-induced HBEC senescence and mitochondrial accumulation via increased DEPTOR expression. These findings suggest that lamin B1 reduction is not only a hallmark of lung aging but is also involved in the progression of cellular senescence during COPD pathogenesis through aberrant MTOR signaling.

PRKN-regulated mitophagy and cellular senescence during COPD pathogenesis.

Cigarette smoke (CS)-induced accumulation of mitochondrial damage has been widely implicated in chronic obstructive pulmonary disease (COPD) pathogenesis. Mitophagy plays a crucial role in eliminating damaged mitochondria, and is governed by the PINK1 (PTEN induced putative protein kinase 1)-PRKN (parkin RBR E3 ubiquitin protein ligase) pathway. Although both increased PINK1 and reduced PRKN have been implicated in COPD pathogenesis in association with mitophagy, there are conflicting reports for the role of mitophagy in COPD progression. To clarify the involvement of PRKN-regulated mitophagy in COPD pathogenesis, prkn knockout (KO) mouse models were used. To illuminate how PINK1 and PRKN regulate mitophagy in relation to CS-induced mitochondrial damage and cellular senescence, overexpression and knockdown experiments were performed in airway epithelial cells (AEC). In comparison to wild-type mice, prkn KO mice demonstrated enhanced airway wall thickening with emphysematous changes following CS exposure. AEC in CS-exposed prkn KO mice showed accumulation of damaged mitochondria and increased oxidative modifications accompanied by accelerated cellular senescence. In vitro experiments showed PRKN overexpression was sufficient to induce mitophagy during CSE exposure even in the setting of reduced PINK1 protein levels, resulting in attenuation of mitochondrial ROS production and cellular senescence. Conversely PINK1 overexpression failed to recover impaired mitophagy caused by PRKN knockdown, indicating that PRKN protein levels can be the rate-limiting factor in PINK1-PRKN-mediated mitophagy during CSE exposure. These results suggest that PRKN levels may play a pivotal role in COPD pathogenesis by regulating mitophagy, suggesting that PRKN induction could mitigate the progression of COPD. Abbreviations: AD: Alzheimer disease; AEC: airway epithelial cells; BALF: bronchoalveolar lavage fluid; AKT: AKT serine/threonine kinase; CALCOCO2/NDP52: calcium binding and coiled-coil domain 2; CDKN1A: cyclin dependent kinase inhibitor 1A; CDKN2A: cyclin dependent kinase inhibitor 2A; COPD: chronic obstructive pulmonary disease; CS: cigarette smoke; CSE: CS extract; CXCL1: C-X-C motif chemokine ligand 1; CXCL8: C-X-C motif chemokine ligand 8; HBEC: human bronchial epithelial cells; 4-HNE: 4-hydroxynonenal; IL: interleukin; KO: knockout; LF: lung fibroblasts; LPS: lipopolysaccharide; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MTOR: mechanistic target of rapamycin kinase; 8-OHdG: 8-hydroxy-2'-deoxyguanosine; OPTN: optineurin; PRKN: parkin RBR E3 ubiquitin protein ligase; PCD: programmed cell death; PFD: pirfenidone; PIK3C: phosphatidylinositol-4:5-bisphosphate 3-kinase catalytic subunit; PINK1: PTEN induced putative kinase 1; PTEN: phosphatase and tensin homolog; RA: rheumatoid arthritis; ROS: reactive oxygen species; SA-GLB1/ß-Gal: senescence-associated-galactosidase, beta 1; SASP: senescence-associated secretory phenotype; SNP: single nucleotide polymorphism; TNF: tumor necrosis factor.

Perioperative outcomes of thoracoscopic lung resection requiring a long operative time.

OBJECTIVES: Difficult thoracoscopic surgery sometimes requires a long operative time. It is unclear whether patients benefit from such thoracoscopic surgeries. We investigated whether thoracoscopic surgery for difficult cases contributed to improvements in perioperative outcomes. METHODS: We retrospectively reviewed cases of anatomical lung resection with thoracoscopic surgery, including conversion to thoracotomy, between January 2006 and December 2016 and compared patient demographics and perioperative outcomes of the long (≥360 min) and the normal operative time groups (<360 min). RESULTS: One hundred and seventy-six patients were in the long operative time group and 655 patients were in the normal operative time group. The long operative time group had more male patients, more progressive clinical stages, bilobectomy or pneumonectomy, conversion to thoracotomy and more blood loss than the normal operative time group. The long operative time group had higher rates of postoperative complications and longer hospital stay (30% vs 16%, P < 0.001 and 9 ± 9 days vs 7 ± 8 days, P < 0.001; respectively). Multivariate analysis showed that in the first half of the operative period, chronic obstructive pulmonary disease and bilobectomy or pneumonectomy were independent predictive factors for postoperative complications. The long operative time as a factor was close to statistical significance (odds ratio 1.689, P = 0.079) unlike the elective conversion to thoracotomy (odds ratio 0.784, P = 0.667) and emergency conversion to thoracotomy (odds ratio 0.938, P = 0.924). CONCLUSIONS: In conclusion, when difficult cases are encountered, conversion to thoracotomy should be considered by surgeons if continuation of thoracoscopic surgery increases the operative time.

Impact of the introduction of thoracoscopic lobectomy for non-small cell lung cancer: a propensity score-matched analysis.

BACKGROUND: The present study evaluated the impact of the introduction of thoracoscopic lung lobectomy (TL) for non-small cell lung cancer at our institution. METHODS: This study retrospectively compared surgical and oncological outcomes in the period before and after the introduction of TL for non-small cell lung cancer. Propensity score-matched analysis was performed with respect to baseline patient variables and tumor characteristics. RESULTS: Patients were divided into two groups: those who underwent lung lobectomy in the period before (BI group, n=261) and after (AI group, n=261) the introduction of TL. The proportion of TLs at our institution increased from 1.3% in the BI group to 93% in the AI group. The AI group experienced a longer duration of surgery, lesser intraoperative blood loss, and a significantly shorter postoperative hospital stay (POHS). There were no significant differences in postoperative complications between the two groups. The median follow-up period was 50 months in both groups. No significant differences were observed between the BI and AI groups with respect to 5-year overall survival (OS) (76.1% and 71.7%, respectively; P=0.1973) and disease-free survival (DFS) (67.6% and 66.1%, respectively; P=0.4071). On multivariate analysis, pathological N1-2 status was an independent predictor of survival. AI group and TL showed no independent association with survival. CONCLUSIONS: The introduction of TL represented a positive change at our institution owing to decreased invasiveness and oncological equivalence of the surgical treatment for non-small cell lung cancer.

Vitamin D Supplementation and Survival of Patients with Non-small Cell Lung Cancer: A Randomized, Double-Blind, Placebo-Controlled Trial.

Purpose: Higher serum 25-hydroxyvitamin D (25(OH)D) levels are reportedly associated with better survival in early-stage non-small cell lung cancer (NSCLC). Therefore, whether vitamin D supplementation can improve the prognosis of patients with NSCLC was examined (UMIN000001869).Patients and Methods: A randomized, double-blind trial comparing vitamin D supplements (1,200 IU/day) with placebo for 1 year after operation was conducted. The primary and secondary outcomes were relapse-free survival (RFS) and overall survival (OS), respectively. Prespecified subgroup analyses were performed with stratification by stage (early vs. advanced), pathology (adenocarcinoma vs. others), and 25(OH)D levels (low, <20 ng/mL vs. high, ≥20 ng/mL). Polymorphisms of vitamin D receptor (VDR) and vitamin D-binding protein (DBP) and survival were also examined.Results: Patients with NSCLC (n = 155) were randomly assigned to receive vitamin D (n = 77) or placebo (n = 78) and followed for a median of 3.3 years. Relapse and death occurred in 40 (28%) and 24 (17%) patients, respectively. In the total study population, no significant difference in either RFS or OS was seen with vitamin D compared with the placebo group. However, by restricting the analysis to the subgroup with early-stage adenocarcinoma with low 25(OH)D, the vitamin D group showed significantly better 5-year RFS (86% vs. 50%, P = 0.04) and OS (91% vs. 48%, P = 0.02) than the placebo group. Among the examined polymorphisms, DBP1 (rs7041) TT and CDX2 (rs11568820) AA/AG genotypes were markers of better prognosis, even with multivariate adjustment.Conclusions: In patients with NSCLC, vitamin D supplementation may improve survival of patients with early-stage lung adenocarcinoma with lower 25(OH)D levels. Clin Cancer Res; 24(17); 4089-97. ©2018 AACR.

Effect of comorbidities on long-term outcomes after thoracoscopic surgery for stage I non-small cell lung cancer patients with chronic obstructive pulmonary disease.

BACKGROUND: We assessed how the severity of chronic obstructive pulmonary disease (COPD) and other comorbidities affect long-term survival after thoracoscopic lung resection for c-stage I non-small cell lung cancer (NSCLC). METHODS: Patients with c-stage I NSCLC who underwent thoracoscopic lung resection at our hospital between 2006 to 2014 were retrospectively analyzed. The Global Initiative for Chronic Obstructive Lung Disease (GOLD) spirometric grades were used to classify the severity of COPD, and comorbidity was classified according to the Charlson comorbidity index (CCI). Various outcomes were assessed and compared. RESULTS: The cohort comprised 404 patients with NSCLC, of whom 133 were diagnosed with COPD (51 as GOLD 1, 79 as GOLD 2, and 3 as GOLD 3) and 271 were diagnosed without COPD. The 5-year overall survival (OS) rates were 86.0%, 80.2%, and 71.1% for the non-COPD, GOLD 1, and GOLD 2/3 groups, respectively (P=0.0221); the corresponding 5-year disease-specific survival (DSS) rates were 91.7%, 86.9%, and 85.1% (P=0.2136). Univariate analysis indicated that sex, smoking status, pathology, COPD severity, CCI, and pathological stage were associated with OS, and multivariate analysis confirmed the association with CCI and pathological stage. Postoperative complications were significantly more frequent in the GOLD 1 (21.5%) and GOLD 2/3 (26.8%) groups than in the non-COPD group (12.1%) (P=0.0040). CONCLUSIONS: Following thoracoscopic surgery (TS) for NSCLC, patients with COPD had a poorer OS than patients without COPD. However, the CCI and not the COPD severity was the independent prognostic factor for OS. Comorbidities adversely affected long-term survival of patients with stage I NSCLC and COPD after TS, and the same effect can be oncologically expected regardless of the COPD severity.

Surgical and oncological outcomes of thoracoscopic thymectomy for thymoma.

Thymoma remains the most common primary anterior mediastinal neoplasm. Surgical resection remains central to the treatment of thymoma, with thoracoscopic thymectomy (TT) being increasingly performed. This present review article aimed to summarize current studies comparing TT and open thymectomy (OT). Recently, most patients with Masaoka stage I-II thymoma have been receiving TT. This procedure is associated with a significantly shorter post-operative hospital stay, decreased intraoperative blood loss, and fewer complications compared with OT. Recurrence rates of thymoma after TT range from 0% to 6.7%, and the 5-year disease-free survival (DFS) ranges from 83.3% to 96%. The oncological outcomes of TT are comparable to that of OT. Masaoka stage and the World Health Organization (WHO) type classification are valuable predictors of the prognosis of thymoma; hence, the optimal treatment for thymoma should be performed according to these two. TT is less invasive, with equivalent oncological outcomes, when compared with the OT. Minimally invasive surgery including TT for stage I-II thymomas is becoming the mainstay of therapy.

Azithromycin attenuates myofibroblast differentiation and lung fibrosis development through proteasomal degradation of NOX4.

Accumulation of profibrotic myofibroblasts is involved in the process of fibrosis development during idiopathic pulmonary fibrosis (IPF) pathogenesis. TGFB (transforming growth factor ß) is one of the major profibrotic cytokines for myofibroblast differentiation and NOX4 (NADPH oxidase 4) has an essential role in TGFB-mediated cell signaling. Azithromycin (AZM), a second-generation antibacterial macrolide, has a pleiotropic effect on cellular processes including proteostasis. Hence, we hypothesized that AZM may regulate NOX4 levels by modulating proteostasis machineries, resulting in inhibition of TGFB-associated lung fibrosis development. Human lung fibroblasts (LF) were used to evaluate TGFB-induced myofibroblast differentiation. With respect to NOX4 regulation via proteostasis, assays for macroautophagy/autophagy, the unfolded protein response (UPR), and proteasome activity were performed. The potential anti-fibrotic property of AZM was examined by using bleomycin (BLM)-induced lung fibrosis mouse models. TGFB-induced NOX4 and myofibroblast differentiation were clearly inhibited by AZM treatment in LF. AZM-mediated NOX4 reduction was restored by treatment with MG132, a proteasome inhibitor. AZM inhibited autophagy and enhanced the UPR. Autophagy inhibition by AZM was linked to ubiquitination of NOX4 via increased protein levels of STUB1 (STIP1 homology and U-box containing protein 1), an E3 ubiquitin ligase. An increased UPR by AZM was associated with enhanced proteasome activity. AZM suppressed lung fibrosis development induced by BLM with concomitantly reduced NOX4 protein levels and enhanced proteasome activation. These results suggest that AZM suppresses NOX4 by promoting proteasomal degradation, resulting in inhibition of TGFB-induced myofibroblast differentiation and lung fibrosis development. AZM may be a candidate for the treatment of the fibrotic lung disease IPF.

Pirfenidone inhibits myofibroblast differentiation and lung fibrosis development during insufficient mitophagy.

BACKGROUND: Pirfenidone (PFD) is an anti-fibrotic agent used to treat idiopathic pulmonary fibrosis (IPF), but its precise mechanism of action remains elusive. Accumulation of profibrotic myofibroblasts is a crucial process for fibrotic remodeling in IPF. Recent findings show participation of autophagy/mitophagy, part of the lysosomal degradation machinery, in IPF pathogenesis. Mitophagy has been implicated in myofibroblast differentiation through regulating mitochondrial reactive oxygen species (ROS)-mediated platelet-derived growth factor receptor (PDGFR) activation. In this study, the effect of PFD on autophagy/mitophagy activation in lung fibroblasts (LF) was evaluated, specifically the anti-fibrotic property of PFD for modulation of myofibroblast differentiation during insufficient mitophagy. METHODS: Transforming growth factor-ß (TGF-ß)-induced or ATG5, ATG7, and PARK2 knockdown-mediated myofibroblast differentiation in LF were used for in vitro models. The anti-fibrotic role of PFD was examined in a bleomycin (BLM)-induced lung fibrosis model using PARK2 knockout (KO) mice. RESULTS: We found that PFD induced autophagy/mitophagy activation via enhanced PARK2 expression, which was partly involved in the inhibition of myofibroblast differentiation in the presence of TGF-ß. PFD inhibited the myofibroblast differentiation induced by PARK2 knockdown by reducing mitochondrial ROS and PDGFR-PI3K-Akt activation. BLM-treated PARK2 KO mice demonstrated augmentation of lung fibrosis and oxidative modifications compared to those of BLM-treated wild type mice, which were efficiently attenuated by PFD. CONCLUSIONS: These results suggest that PFD induces PARK2-mediated mitophagy and also inhibits lung fibrosis development in the setting of insufficient mitophagy, which may at least partly explain the anti-fibrotic mechanisms of PFD for IPF treatment.

A step-by-step development of real-size chest model for simulation of thoracoscopic surgery.

OBJECTIVES: For the purpose of simulating thoracoscopic surgery, we have conducted stepwise development of a life-like chest model including thorax and intrathoracic organs. METHODS: First, CT data of the human chest were obtained. First-generation model: based on the CT data, each component of the chest was made from a 3D printer. A hard resin was used for the bony thorax and a rubber-like resin for the vessels and bronchi. Lung parenchyma, muscles and skin were not created. Second-generation model: in addition to the 3D printer, a cast moulding method was used. Each part was casted using a 3D printed master and then assembled. The vasculature and bronchi were casted using silicon resin. The lung parenchyma and mediastinum organs were casted using urethane foam. Chest wall and bony thorax were also casted using a silicon resin. Third-generation model: foamed polyvinyl alcohol (PVA) was newly developed and casted onto the lung parenchyma. The vasculature and bronchi were developed using a soft resin. A PVA plate was made as the mediastinum, and all were combined. RESULTS: The first-generation model showed real distribution of the vasculature and bronchi; it enabled an understanding of the anatomy within the lung. The second-generation model is a total chest dry model, which enabled observation of the total anatomy of the organs and thorax. The third-generation model is a wet organ model. It allowed for realistic simulation of surgical procedures, such as cutting, suturing, stapling and energy device use. This single-use model achieved realistic simulation of thoracoscopic surgery. CONCLUSIONS: As the generation advances, the model provides a more realistic simulation of thoracoscopic surgery. Further improvement of the model is needed.

Thoracoscopic thymectomy is a feasible and less invasive alternative for the surgical treatment of large thymomas.

OBJECTIVES: Thoracoscopic surgery is widely used for the surgical treatment of thymoma. However, large-sized thymomas are typically treated using open surgery. This study evaluated the feasibility of performing thoracoscopic thymectomy (TT) for thymoma ≥50 mm. METHODS: A retrospective review was conducted on 135 patients who underwent TT or open thymectomy (OT) for Masaoka stage I-IVa thymoma between 1996 and 2014. RESULTS: Patients were first divided into two groups based on thymoma size: thymoma ≥50 mm and thymoma <50 mm groups. There was no significant difference in the 5-year disease-free survival (DFS) between the groups ( P = 0.5352). Patients in the thymoma ≥50 mm group were further subdivided into TT and OT groups. The length of postoperative hospital stay was significantly shorter in the TT group than in the OT group (5 vs 14 days, P < 0.0001), with significantly fewer postoperative complications (6 patients vs 14 patients, P = 0.0008). There was no significant difference in the 5-year DFS between patients with thymoma ≥50 mm in the TT and OT groups ( P = 0.3501). Finally, patients undergoing TT were further subdivided into thymoma ≥50 mm and thymoma <50 mm groups and, no significant difference in the 5-year DFS was found between these groups ( P = 0.6661). Masaoka stages III-IV, but not thymoma size, were an independent prognostic factor for DFS. CONCLUSIONS: These results demonstrate the decreased invasiveness and feasibility of TT for large-sized thymomas.

Comparison of oncological results for early- and advanced-stage thymomas: thoracoscopic thymectomy versus open thymectomy.

BACKGROUND: This study evaluated the feasibility of thoracoscopic thymectomy (TT) for the treatment of early- and advanced-stage thymoma and compared patient outcomes with those following open thymectomy (OT). METHODS: A retrospective review was conducted for 140 patients who underwent TT or OT for Masaoka stage I-IV thymoma between 1996 and 2014. RESULTS: TT was performed in 88 patients and OT in 52 patients. The postoperative hospital stay was significantly shorter in the TT group than in the OT group (4 and 13 days, respectively; P < 0.0001). WHO types B3-C were identified in Masaoka stage III-IV disease with high frequency. There was a significant relationship between Masaoka stage and WHO type (P < 0.05); the numbers of advanced-stage thymoma progressively increased in WHO type B3-C. Eight patients in each group had recurrent disease, with greater recurrence for WHO types B3-C and stage III-IV tumors. Five-year disease-free survival (DFS) was not different between groups (P = 0.3906); however, survival for patients with stage III-IV thymomas (47 %) was significantly worse than that for patients with stage I and II tumors (97.5 and 94.1 %, respectively; P < 0.0001). Based on multivariate analysis, both Masaoka stage and WHO type were significant predictors of thymoma patient survival. CONCLUSIONS: These results demonstrate the safety and substantially decreased invasiveness of TT for thymoma. The oncological results were comparable between the TT and OT groups. Furthermore, Masaoka stage III-IV and WHO B3-C were revealed as independent prognostic factors for DFS.

Involvement of PARK2-Mediated Mitophagy in Idiopathic Pulmonary Fibrosis Pathogenesis.

Fibroblastic foci, known to be the leading edge of fibrosis development in idiopathic pulmonary fibrosis (IPF), are composed of fibrogenic myofibroblasts. Autophagy has been implicated in the regulation of myofibroblast differentiation. Insufficient mitophagy, the mitochondria-selective autophagy, results in increased reactive oxygen species, which may modulate cell signaling pathways for myofibroblast differentiation. Therefore, we sought to investigate the regulatory role of mitophagy in myofibroblast differentiation as a part of IPF pathogenesis. Lung fibroblasts were used in in vitro experiments. Immunohistochemical evaluation in IPF lung tissues was performed. PARK2 was examined as a target molecule for mitophagy regulation, and a PARK2 knockout mouse was employed in a bleomycin-induced lung fibrosis model. We demonstrated that PARK2 knockdown-mediated mitophagy inhibition was involved in the mechanism for activation of the platelet-derived growth factor receptor (PDGFR)/PI3K/AKT signaling pathway accompanied by enhanced myofibroblast differentiation and proliferation, which were clearly inhibited by treatment with both antioxidants and AG1296, a PDGFR inhibitor. Mitophagy inhibition-mediated activation of PDGFR signaling was responsible for further autophagy suppression, suggesting the existence of a self-amplifying loop of mitophagy inhibition and PDGFR activation. IPF lung demonstrated reduced PARK2 with concomitantly increased PDGFR phosphorylation. Furthermore, bleomycin-induced lung fibrosis was enhanced in PARK2 knockout mice and subsequently inhibited by AG1296. These findings suggest that insufficient mitophagy-mediated PDGFR/PI3K/AKT activation, which is mainly attributed to reduced PARK2 expression, is a potent underlying mechanism for myofibroblast differentiation and proliferation in fibroblastic foci formation during IPF pathogenesis.