Lung regeneration with rat fetal lung implantation and promotion of alveolar stem cell differentiation by corticosteroids.

Introduction: The lung is a difficult organ to regenerate, and the development of functional lungs has still not been achieved. In this study, we investigated lung regeneration using a rat fetal lung tissue-implanted model. This study aimed to evaluate the functioning of the implanted fetal lung tissue and investigate the graft differentiation and maturation mechanism, focusing on alveolar stem cells. Methods: Fetal lung tissue fragments were obtained from Lewis rats on day 17 and implanted into adult lungs. Animals were divided into the following three groups: group 1, injection into the adult left lung parenchyma; group 2, injection with post-caval lobectomy; and group 3, injection with post-caval lobectomy and corticosteroid administration. Computed tomography was performed on weeks 1, 2, 4, and 8. The presence of alveolar pore, CD31 expression, and bipotential progenitor cell (podoplanin+/surfactant protein C+) localization were histologically evaluated. MiRNA expression was comprehensively compared among the three groups. Results: The grafts comprised type I and type II alveolar cells connected to the recipient lungs with alveolar pores and capillary networks in the interstitial tissue. The alveolar space was the largest and the computed tomography value was the lowest in the grafts of the corticosteroid-administered group. The number of bipotential progenitor cells was the lowest in the corticosteroid administration group on day 7. Moreover, microRNA-487-3p, 374-5p, and 20b-5p expression was changed by more than 2-fold between the post-caval lobectomy and corticosteroid administration groups. Conclusions: Implanted fetal lung tissues established airway and capillary communication with the recipient lungs, and corticosteroids accelerated their maturation by promoting the differentiation of progenitor cells. The study findings provide new insights into lung regeneration research.

Cone-beam computed tomography-guided endobronchial ultrasound using an ultrathin bronchoscope for diagnosis of peripheral pulmonary lesions: a prospective pilot study.

Background: Multimodal transbronchial biopsy (TBB) may have improved diagnostic yield for peripheral pulmonary lesions suspected as lung cancer. Radial endobronchial ultrasound (R-EBUS) provides real-time imaging and confirmation of the location of the lesions. Cone-beam computed tomography (CBCT) can confirm that the forceps tip has reached the lesion before biopsy. Methods: Patients with peripheral pulmonary lesions and a positive computed tomography (CT) bronchus sign (based on slice thickness of 1 mm) were prospectively enrolled. An ultrathin bronchoscope (UTB) and R-EBUS probe were advanced to the target bronchus. Thereafter, forceps were advanced, and CBCT was performed. R-EBUS was performed for re-navigation, if possible. The obtained EBUS and CBCT images were classified into "within" (type 1), "adjacent to" (type 2), or "far from" (type 3), based on the probe or forceps tip. Results: For 20 lesions, the diagnostic yield was 85%. The primary EBUS images were of types 1, 2, and 3 in 12, 6, and 2 cases, respectively. The primary CBCT images were of types 1, 2, and 3 in 12, 6, and 2 cases, respectively. Primary EBUS and CBCT image types were equivalent in 14 cases. Of the 12 cases with type 1 primary EBUS image, 9 cases had a type 1 primary CBCT image, while 3 cases exhibited positional misalignment of the forceps tip. Re-navigation was required in 8 cases with types 2 and 3 primary CBCT images. Conclusions: CBCT-guided TBB using an UTB and EBUS may enable real-time positioning guidance and better re-navigation in the diagnosis of peripheral pulmonary lesions.

Type A thymoma: a rare cause of neoplastic cardiac tamponade with long-term survival.

BACKGROUND: The prognosis of thymoma with cardiac tamponade is generally poor. Most of the reported thymomas with cardiac tamponade were type B or type AB (mixed thymoma), and cardiac tamponade due to type A thymoma, which has a better prognosis compared to type B thymoma, is extremely rare. CASE PRESENTATION: We encountered a case of cardiac tamponade in a 71-year-old male. He visited our emergency department due to exacerbation of fatigue and dyspnea on exertion that lasted for two weeks. Chest imaging revealed a large amount of pericardial fluid and a contrast-enhanced tumor with calcification in the anterior mediastinum. The patient underwent thoracoscopic tumor biopsy and pathological examinations revealed type A thymoma. In this case, long-term disease-free survival (7.5 years) was achieved by multidisciplinary treatment (preoperative chemotherapy, surgical excision, and postoperative radiation therapy), in accordance with the histological type. CONCLUSIONS: This case indicates that neoplastic cardiac tamponade, even in elderly patients, should not necessarily be regarded as a terminal cancer and requires a systematic investigation for underlying causes.

Hypervascularized bronchial arteries as a risk factor for intraoperative bleeding and prolonged surgery.

BACKGROUND: The present study investigated whether highly vascularized bronchial arteries affect the intraoperative blood loss and the operative time of video-assisted thoracic surgery (VATS) lobectomy for patients with non-small cell lung cancer.Methods: We retrospectively collected data on consecutive pathological stage I to IIIA non-small cell lung cancer patients who underwent VATS lobectomy with systematic lymph node dissection between January 2017 and December 2019. Patients were divided into the following two groups according to bronchial artery diameters on preoperative enhanced contrast computed tomography (CT) findings: ≤2 and >2 mm groups. RESULTS: Among the 175 patients enrolled, risk factors for intraoperative blood loss >50 mL were being male (P=0.005), a history of smoking (P=0.01), percent forced expiratory volume in 1 s (FEV1.0%) <70% (P=0.012), squamous cell carcinoma (P=0.049), and a bronchial artery diameter >2.0 mm (P<0.001) in the unadjusted analysis, and a bronchial artery diameter >2.0 mm (P<0.001) in the multivariable analysis. Risk factors for an operative time >200 min were being male (P<0.001), a history of smoking (P=0.007), FEV1.0% <70% (P=0.011), squamous cell carcinoma (P=0.046), a bronchial artery diameter >2.0 mm (P<0.001), and experience of surgeon <10 years (P=0.011) in the unadjusted analysis, and being male (P=0.047), a bronchial artery diameter >2.0 mm (P=0.024), and experience of surgeon <10 years (P=0.047) in the multivariable analysis. CONCLUSIONS: Bronchial artery diameter was the most important risk factor of intraoperative bleeding and prolonged operative time during VATS lobectomy.

Diagnosis of visceral pleural invasion using confocal laser endomicroscopy during lung cancer surgery.

BACKGROUND: Visceral pleural invasion (VPI) in lung cancer is a significant prognostic factor; however, it is difficult to diagnose preoperatively or intraoperatively. In this study, we examined the possibility of intraoperative diagnosis of VPI using confocal laser endomicroscopy (CLE). METHODS: Among patients with primary lung cancer who underwent surgery between April 2018 and August 2019, those in whom the tumor was in contact with the pleura on chest computed tomography and whose pleural changes were intraoperatively confirmed were enrolled in this study. In the 35 patients who underwent lung resection (6 cases with visceral pleural infiltration), the area where pleural change was noted was observed and a short video was recorded using CLE. Based on the video images, three evaluators determined the defect ratio (0%, 25%, 50%, 75%, and 100%) of the autofluorescence-positive structure. The area under the receiver operating characteristic curve was used to evaluate the diagnostic performance for VPI. In 15 cases (3 cases with VPI), a validation study was performed for intraoperative VPI according to the cutoff value of the defect ratio of the autofluorescence-positive structure. RESULTS: The areas under the receiver operating characteristic curve for the defect ratio of the autofluorescence-positive structure were 0.86-0.91 for the three readers. Using defect ratio of autofluorescence-positive structure cutoff of ≥50% as predictor of VPI, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 83.3-100.0%, 57.7-73.1%, 35.3-41.7%, 95.0-100.0%, and 75.0-78.1%, respectively, for the three readers. In the validation study, the sensitivity was 100%, the specificity was 83.3%, and the diagnostic accuracy rate was 86.7%. CONCLUSIONS: The diagnosis of VPI through CLE is simple, non-invasive, and has high diagnostic accuracy rates. This method may be applicable for determining surgical procedures.

Cone-beam computed tomography versus computed tomography-guided ultrathin bronchoscopic diagnosis for peripheral pulmonary lesions: A propensity score-matched analysis.

BACKGROUND AND OBJECTIVE: CBCT-guided TBB using a UTB under VBN is a useful method for the diagnosis of peripheral small pulmonary lesions. CBCT-guided TBB using UTB under VBN has been used as an alternative to CT-guided TBB. However, the advantage of CBCT-guided TBB using UTB under VBN over CT-guided TBB is still unknown. This study aimed to compare the diagnostic yield of CT-guided TBB and CBCT-guided TBB using a propensity score-matched analysis. METHODS: Patients with peripheral pulmonary lesions ≤30 mm were included. Lesions whose bronchus could not be determined by CT were excluded. A UTB and biopsy forceps were advanced to the target bronchus under VBN, 2D-fluoroscopy and CT or CBCT. The CT-guided and CBCT-guided groups were matched for their propensity scores based on patient characteristics. RESULTS: We retrospectively reviewed 93 patients in the CT-guided group and 79 patients in the CBCT-guided group for this study. Furthermore, 48 distinct examination pairs were generated by propensity score matching. In the overall diagnostic yield, the CBCT-guided group showed better results (72.9%) than did the CT-guided group (47.9%) (P = 0.012). The median examination time lasted for 43 (IQR: 37-51) min in the CBCT-guided group and 50 (IQR: 43-62) min in the CT-guided group. The examination time in the CBCT-guided group was significantly shorter than that of the CT-guided group (P = 0.001). CONCLUSION: CBCT-guided TBB had a better diagnostic yield and shorter examination time than did CT-guided TBB.

Classifying the destination of right top pulmonary vein in 31 clinical cases.

Disruption in the flow of blood vessels is of great concern during thoracic surgery. Preoperative 3-dimensional computed tomography facilitates visualization of the exact location and course of blood vessels. The right posterior upper lobe segmental vein, known as the right top pulmonary vein (RTPV), is an anomalous vein beginning at the right upper lobe and running through the posterior surface of the intermediate bronchus. We clinically investigated 31 patients with RTPV who underwent lobectomy or total resection of the right lung in our hospital or related institutions. We classified the final destination of RTPV into four types. The RTPV flowed into the left atrium in 35.5% of cases, superior pulmonary vein in 9.7%, inferior pulmonary vein in 41.9%, and independently into V6 in 12.9%. An RTPV with a diameter ≥ 5 mm was considered a main drainage vein in S2. We should pay attention to the RTPV during right lung lobectomy.

Diagnosis of recurrence and follow-up using FDG-PET/CT for postoperative non-small-cell lung cancer patients.

BACKGROUND: There is currently no consensus regarding the best program for postoperative follow-up and surveillance after a curative resection for non-small-cell lung cancer (NSCLC) patients. We examined the diagnostic capability of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) for detecting recurrence in postoperative NSCLC patients, and we evaluated the results of postoperative surveillance using FDG-PET/CT in asymptomatic patients. PATIENTS AND METHODS: Between 2005 and 2013, 496 FDG-PET/CT examinations were performed to detect recurrences for 187 NSCLC patients who had undergone potentially curative operations at our institution. Follow-up FDG-PET/CT was performed ≥ 1 × /year in principle in 172 asymptomatic patients without clinical or radiological evidence of recurrence, and the results were retrospectively reviewed. RESULTS: FDG-PET/CT correctly diagnosed recurrence in 46 of 47 (97.9%) patients and 68 of 69 (98.6%) recurrent sites. The following were obtained: 97.9% sensitivity, 97.1% specificity, 92.0% positive predictive value, 99.3% negative predictive value, and 97.3% accuracy. In six patients, other diseases were detected and treated appropriately. In asymptomatic patients, the detection rate of recurrence in the stage III group was significantly higher than the detection rates in the stage I and II groups, and FDG-PET/CT performed ≤ 3 years post-resection detected significantly more FDG-positive lesions compared to that performed after 4 years. CONCLUSION: FDG-PET/CT is very useful for detecting recurrence in NSCLC patients after a potentially curative operation. It might be sufficient to perform follow-up FDG-PET/CT until 3 years post-resection for advanced-stage patients. Further randomized clinical trials are needed to determine whether the early detection of recurrences leads to better prognoses.

Bronchioalveolar stem cells derived from mouse-induced pluripotent stem cells promote airway epithelium regeneration.

BACKGROUND: Bronchioalveolar stem cells (BASCs) located at the bronchioalveolar-duct junction (BADJ) are stem cells residing in alveoli and terminal bronchioles that can self-renew and differentiate into alveolar type (AT)-1 cells, AT-2 cells, club cells, and ciliated cells. Following terminal-bronchiole injury, BASCs increase in number and promote repair. However, whether BASCs can be differentiated from mouse-induced pluripotent stem cells (iPSCs) remains unreported, and the therapeutic potential of such cells is unclear. We therefore sought to differentiate BASCs from iPSCs and examine their potential for use in the treatment of epithelial injury in terminal bronchioles. METHODS: BASCs were induced using a modified protocol for differentiating mouse iPSCs into AT-2 cells. Differentiated iPSCs were intratracheally transplanted into naphthalene-treated mice. The engraftment of BASCs into the BADJ and their subsequent ability to promote repair of injury to the airway epithelium were evaluated. RESULTS: Flow cytometric analysis revealed that BASCs represented ~ 7% of the cells obtained. Additionally, ultrastructural analysis of these iPSC-derived BASCs via transmission electron microscopy showed that the cells containing secretory granules harboured microvilli, as well as small and immature lamellar body-like structures. When the differentiated iPSCs were intratracheally transplanted in naphthalene-induced airway epithelium injury, transplanted BASCs were found to be engrafted in the BADJ epithelium and alveolar spaces for 14 days after transplantation and to maintain the BASC phenotype. Notably, repair of the terminal-bronchiole epithelium was markedly promoted after transplantation of the differentiated iPSCs. CONCLUSIONS: Mouse iPSCs could be differentiated in vitro into cells that display a similar phenotype to BASCs. Given that the differentiated iPSCs promoted epithelial repair in the mouse model of naphthalene-induced airway epithelium injury, this method may serve as a basis for the development of treatments for terminal-bronchiole/alveolar-region disorders.

Use of a prognostic risk score that aggregates the FDG-PET/CT SUVmax, tumor size, and histologic group for predicting the prognosis of pStage I lung adenocarcinoma.

BACKGROUND: pStage I includes clinicopathologically diverse groups. This study aimed to identify the prognostic factors for pStage I lung adenocarcinoma. METHODS: We retrospectively reviewed 208 patients with pStage I adenocarcinomas who underwent curative resection in our institute between 2006 and 2013. The maximum standardized uptake value (SUVmax) on [F18]-fluoro-deoxy-D-glucose positron emission tomography-computed tomography (PET/CT) was evaluated. Adenocarcinomas were categorized into the following histologic groups: group 0 (minimally invasive adenocarcinoma and lepidic predominant adenocarcinoma), group 1 (papillary predominant adenocarcinoma), and group 2 (acinar predominant adenocarcinoma and all the remaining subtypes). We assessed the relationship between disease-free survival (DFS) and clinicopathological factors. RESULTS: Multivariate analysis of DFS demonstrated that SUVmax > 3.0 (p < 0.001), total tumor size > 20 mm (p = 0.016), and histologic groups (p < 0.05) were independent prognostic factors. The prognostic risk score (PRS) was calculated using the following equation: PRS = SUVmax (≤ 3.0: 0 point, > 3.0: 2 points) + total tumor size (≤ 20 mm: 0 point, > 20 mm: 1 point) + histologic group (group 0: 0 point, group 1: 1 point, group 2: 2 points). Patients were divided into the following three risk groups: low-risk (PRS 0-2 points, n = 136), intermediate-risk (PRS 3-4 points, n = 49), and high-risk groups (PRS 5 points, n = 13). The 5-year DFS rates were 93.2%, 50.6%, and 30.8% for the low-, intermediate-, and high-risk groups, respectively (p < 0.001). CONCLUSIONS: The PRS aggregating the FDG-PET/CT SUVmax, total tumor size, and histologic group predicts the prognosis of pStage I lung adenocarcinoma.

Transbronchial Biopsy Using an Ultrathin Bronchoscope Guided by Cone-Beam Computed Tomography and Virtual Bronchoscopic Navigation in the Diagnosis of Pulmonary Nodules.

BACKGROUND: Transbronchial biopsy is a safe diagnostic approach for patients with peripheral pulmonary lesions; however, the diagnostic yield is low. OBJECTIVES: This study was conducted to evaluate the feasibility and diagnostic yield of transbronchial biopsy using the combination of an ultrathin bronchoscope, virtual bronchoscopic navigation (VBN), and cone-beam computed tomography (CBCT). METHODS: Patients with peripheral pulmonary lesions, no >30 mm, with the responsible bronchus, were prospectively included. An ultrathin bronchoscope and biopsy forceps were advanced to the target bronchus under VBN, 2D-fluoroscopy, and CBCT. We categorized the CBCT findings before biopsy into 3 types according to positions of the target lesion and forceps (CBCT target-forceps sign). In type A, the forceps reached the inside of the target lesion. In type C, the forceps could not reach the lesion. When the CBCT findings could not be categorized into either type A or C, the sign was categorized as type B. RESULTS: Although the target lesions were invisible by conventional C-arm fluoroscopy in 29 patients, CBCT visualized all 40 lesions. The overall diagnostic yield was 90.0%, and diagnostic yields for malignant and benign lesions were 92.0 and 86.7%, respectively. Diagnostic yields for CBCT target-forceps sign types A, B, and C were 100, 75.0, and 0%, respectively. Four undiagnosed patients proceeded to other diagnostic procedures based on the CBCT target-forceps sign (type B: n = 2, type C: n = 2) and were correctly diagnosed without delay. CONCLUSIONS: Transbronchial biopsy using an ultrathin bronchoscope guided by CBCT and VBN showed a very high yield in the diagnosis of pulmonary nodules.

[A case of a patient with stage IVa esophageal cancer surviving over 4 years by combination chemotherapy with docetaxel,5 -FU and cisplatin, without operation].

A male patient in his 50s was found to have lower thoracic advanced esophageal squamous cell carcinoma by upper gastrointestinal endoscopy with the chief complaint of dysphagia in July 2006. CT revealed supraclavicular lymph node metastasis, and he was diagnosed as clinical stage IVa. He underwent two courses of combination chemotherapy with docetaxel, 5-FU and cisplatin(DFP therapy: docetaxel at 25mg/m / / 2 on day 1, 5-FU at 370 mg/m2 on days 1-5, and cisplatin at 7 mg/m2 on days 1-5 were repeated weekly for 4 weeks). The primary tumor disappeared and the lymph node was reduced as observed by upper gastrointestinal endoscopy and CT. After 2 courses of DFP therapy, PET-CT revealed that the primary tumor and lymph node had no new accumulation. Because he refused both operation and chemoradiotherapy, the patient underwent oral chemotherapy. In January 2010, PET-CT and upper gastrointestinal endoscopy revealed that the primary tumor relapsed. DFP therapy was performed and was effective once again. He has survived for over 4 years and 4 months without operation.