Purinergic P2Y2 receptor-induced activation of endothelial TRPV4 channels mediates lung ischemia-reperfusion injury.

Lung ischemia-reperfusion injury (IRI), characterized by inflammation, vascular permeability, and lung edema, is the major cause of primary graft dysfunction after lung transplantation. Here, we investigated the cellular mechanisms underlying lung IR-induced activation of endothelial TRPV4 channels, which play a central role in lung edema and dysfunction after IR. In a left lung hilar-ligation model of IRI in mice, we found that lung IRI increased the efflux of ATP through pannexin 1 (Panx1) channels at the endothelial cell (EC) membrane. Elevated extracellular ATP activated Ca2+ influx through endothelial TRPV4 channels downstream of purinergic P2Y2 receptor (P2Y2R) signaling. P2Y2R-dependent activation of TRPV4 channels was also observed in human and mouse pulmonary microvascular endothelium in ex vivo and in vitro models of IR. Endothelium-specific deletion of P2Y2R, TRPV4, or Panx1 in mice substantially prevented lung IRI-induced activation of endothelial TRPV4 channels and lung edema, inflammation, and dysfunction. These results identify endothelial P2Y2R as a mediator of the pathological sequelae of IRI in the lung and show that disruption of the endothelial Panx1-P2Y2R-TRPV4 signaling pathway could be a promising therapeutic strategy for preventing lung IRI after transplantation.

Purinergic P2Y2 Receptor-Induced Activation of Endothelial TRPV4 Channels Mediates Lung Ischemia-Reperfusion Injury.

Lung ischemia-reperfusion injury (IRI), characterized by inflammation, vascular permeability, and lung edema, is the major cause of primary graft dysfunction after lung transplantation. We recently reported that endothelial cell (EC) TRPV4 channels play a central role in lung edema and dysfunction after IR. However, the cellular mechanisms for lung IR-induced activation of endothelial TRPV4 channels are unknown. In a left-lung hilar ligation model of IRI in mice, we found that lung IR increases the efflux of extracellular ATP (eATP) through pannexin 1 (Panx1) channels at the EC membrane. Elevated eATP activated elementary Ca2+ influx signals through endothelial TRPV4 channels through purinergic P2Y2 receptor (P2Y2R) signaling. P2Y2R-dependent activation of TRPV4 channels was also observed in human and mouse pulmonary microvascular endothelium in ex vivo and in vitro surrogate models of lung IR. Endothelium-specific deletion of P2Y2R, TRPV4, and Panx1 in mice had substantial protective effects against lung IR-induced activation of endothelial TRPV4 channels, lung edema, inflammation, and dysfunction. These results identify endothelial P2Y2R as a novel mediator of lung edema, inflammation, and dysfunction after IR, and show that disruption of endothelial Panx1-P2Y2R-TRPV4 signaling pathway could represent a promising therapeutic strategy for preventing lung IRI after transplantation.

Quantitative assessment of gastric ischemic preconditioning on conduit perfusion in esophagectomy: propensity score weighting study.

BACKGROUND: Gastric ischemic preconditioning prior to esophagectomy has been studied as a method to improve gastric conduit perfusion and reduce anastomotic complications, without conclusive results. The aim of this study is to evaluate the feasibility and safety of gastric ischemic preconditioning in terms of post-operative outcomes and quantitative gastric conduit perfusion. METHODS: Patients who underwent an esophagectomy with gastric conduit reconstruction between January 2015 and October 2022 at a single high-volume academic center were reviewed. Patient characteristics, surgical approach, post-operative outcomes, and indocyanine green fluorescence angiography data (ingress index for arterial inflow and ingress time for venous outflow, and the distance from the last gastroepiploic branch to the perfusion assessment point) were analyzed. Two propensity score weighting methods were used to investigate whether gastric ischemic preconditioning reduces anastomotic leaks. Multiple linear regression analysis was used to evaluate the conduit perfusion quantitatively. RESULTS: There were 594 esophagectomies with gastric conduit performed, with 41 having a gastric ischemic preconditioning. Among 544 with cervical anastomoses, leaks were seen in 2/30 (6.7%) in the ischemic preconditioning group and 114/514 (22.2%) in the control group (p = 0.041). Gastric ischemic preconditioning significantly reduced anastomotic leaks on both weighting methods (p = 0.037 and 0.047, respectively). Ingress index and time of the gastric conduit with ischemic preconditioning were significantly better than those without preconditioning (p = 0.013 and 0.025, respectively) after removing the effect of the distance from the last gastroepiploic branch to the perfusion assessment point. CONCLUSION: Gastric ischemic preconditioning results in a statistically significant improvement in conduit perfusion and reduction in post-operative anastomotic leaks.

Higher Long-term Quality of Life Metrics After Video-Assisted Thoracoscopic Surgery Lobectomy Compared With Robotic-Assisted Lobectomy.

BACKGROUND: Robotic-assisted thoracic surgery (RATS) lung lobectomy has emerged as an alternative approach to video-assisted thoracoscopic surgery (VATS). Patient-reported outcomes comparing these approaches have been limited. METHODS: At a single, high-volume academic center, patients undergoing VATS and RATS lobectomies for stage I and II non-small cell lung cancer from 2014 to 2018 were evaluated. The European Organisation for Research and Treatment of Cancer Quality of Life of Cancer Patients Questionnaire (QLQ-C30) and Quality of Life Questionnaire in Lung Cancer (QLQ-LC13), along with the Fear of Recurrence (FoR) survey, were administered preoperatively and at 1, 6, and 12 months postoperatively. Raw scores underwent linear transformation (0-100 scale). Linear mixed-effects models were used for quality of life and FoR score comparisons. RESULTS: The study included 219 patients (139 VATS and 80 RATS). RATS patients had longer (P < .05) operative times and a higher incidence (P < .05) of postoperative myocardial infarction compared to VATS patients. VATS patients reported higher (P < .05) QLQ-C30 summary scores postoperatively and at 12 months, including higher (P < .05) Social Functioning and Cognitive scores, and less (P < .05) appetite loss. VATS patients reported decreased (P < .05) QLQ-LC13 symptom summary scores at 6 months postoperatively, including decreased (P < .05) dyspnea, neuropathy, and pain compared with RATS patients. VATS patients also reported lower (P < .05) FoR summary scores at 6 months postoperatively. CONCLUSIONS: VATS patients report improvement in select quality of life and FoR measures after lobectomy. Further study comparing these 2 approaches is required.

Transhiatal robot-assisted minimally invasive esophagectomy: unclear benefits compared to traditional transhiatal esophagectomy.

Esophagectomy is a high-risk operation, regardless of technique. Minimally invasive transthoracic esophagectomy could reduce length of stay and pulmonary complications compared to traditional open approaches, but the benefits of minimally invasive transhiatal esophagectomy are unclear. We performed a retrospective review of prospectively gathered data for open transhiatal esophagectomies (THEs) and transhiatal robot-assisted minimally invasive esophagectomies (TH-RAMIEs) performed at a high-volume academic center between 2013 and 2017. Multivariate logistic regression was used to calculate adjusted odds ratios (aORs) for outcomes. 465 patients met inclusion criteria (378 THE and 87 TH-RAMIE). THE patients more likely had an ASA score of 3 + (89.1% vs 77.0%, p = 0.012), whereas TH-RAMIE patients more likely had a pathologic staging of 3+ (43.7% vs. 31.2%, p = 0.026). TH-RAMIE patients were less likely to receive epidurals (aOR 0.06, 95% confidence interval [CI] 0.03-0.14, p < 0.001), but epidural use itself was not associated with differences in outcomes. TH-RAMIE patients experienced higher rates of pulmonary complications (adjusted odds ratio [OR] 1.82, 95% CI 1.03-3.22, p = 0.040), particularly pulmonary embolus (aOR 5.20, 95% CI 1.30-20.82, p = 0.020). There were no statistically significant differences in lymph node harvest, unexpected ICU admission, length of stay, in-hospital mortality, or 30-day readmission or mortality rates. The TH-RAMIE approach had higher rates of pulmonary complications. There were no statistically significant advantages to the TH-RAMIE approach. Further investigation is needed to understand the benefits of a minimally invasive approach to the open transhiatal esophagectomy.

Are Esophagectomy Board Requirements Achievable? A Multi-Institutional Analysis.

Duty-hour restrictions have implications on trainee operative exposure necessary to meet minimum case-volume requirements. We utilized a previously validated simulation model to evaluate the effect of program volume, trainee numbers and complement, and rotation schedule on the probability of achieving adequate esophagectomy case numbers for cardiothoracic surgery trainees. A ProModel simulator centered on probabilistic distributions of operative cases was utilized. Historical data from five 2-year cardiothoracic surgery training programs were obtained from 2016-2018 and used as inputs to the simulator that generated 10,000 "trainee 2-year periods" per program. Programs varied in annual average esophagectomy volume (12-91 per year), with 2-4 trainees graduating over a 2-year training period. If esophagectomy cases were distributed solely based on scheduling and institutional volume, only 60% of evaluated programs could adequately expose all trainees in esophagectomy to meet case requirements. The 3 programs with adequate esophagectomy volumes had averaged 3.3 times (range 3.0-3.6) the minimum number of board-required cases for their programs' trainees. The ability of programs to provide trainees with adequate esophagectomy volume is challenging based on institutional volume and scheduling. Through simulation, we demonstrate that programs need >2 times the expected minimum number of esophagectomies to ensure that >90% of trainees meet case-volume requirements. Programs may consider strategies such as allowing trainees to select cases based on personal need, train fewer fellows, or enable trainees to seek subspecialty exposure externally to achieve minimum esophagectomy case-load requirements.

Long-Term Quality of Life Following Endoscopic Therapy Compared to Esophagectomy for Neoplastic Barrett's Esophagus.

INTRODUCTION: Endoscopic therapy (ET) and esophagectomy result in similar survival for Barrett's esophagus (BE) with high-grade dysplasia (HGD) or T1a esophageal adenocarcinoma (EAC), but the long-term quality of life (QOL) has not been compared. AIMS: We aimed to compare long-term QOL between patients who had undergone ET versus esophagectomy. METHODS: Patients were included if they underwent ET or esophagectomy at the University of Michigan since 2000 for the treatment of HGD or T1a EAC. Two validated survey QOL questionnaires were mailed to the patients. We compared QOL between and within groups (ET = 91, esophagectomy = 62), adjusting for covariates. RESULTS: The median time since initial intervention was 6.8 years. Compared to esophagectomy, ET patients tended to be older, had a lower prevalence of EAC, and had a shorter duration since therapy. ET patients had worse adjusted physical and role functioning than esophagectomy patients. However, the adjusted odds ratio (OR) of having symptoms was significantly less with ET for diarrhea (0.287; 95% confidence interval [CI] = 0.114, 0.724), trouble eating (0.207; 0.0766, 0.562), choking (0.325; 0.119, 0.888), coughing (0.291; 0.114, 0.746), and speech difficulty (0.306; 0.0959, 0.978). Amongst the ET patients, we found that the number of therapy sessions and need for dilation were associated with worse outcomes. DISCUSSION: Multiple measures of symptom status were better with ET compared to esophagectomy following treatment of BE with HGD or T1a EAC. We observed worse long-term physical and role functioning in ET patients which could reflect unmeasured baseline functional status rather than a causal effect of ET.

Diagnostic Laparoscopy Improves Staging of Malignant Pleural Mesothelioma With Routine Positron Emission Tomography Imaging.

BACKGROUND: With a multimodal treatment strategy, cytoreductive surgery extends survival in malignant pleural mesothelioma. Improving the accuracy of staging can refine patient selection. Our objective was to determine whether diagnostic laparoscopy (DL) improves staging for patients with malignant pleural mesothelioma with the routine use of positron emission tomography (PET). METHODS: We performed a retrospective review of our prospectively maintained database from February 2014 to May 2019. Inclusion criteria were patients who had disease in the chest that was deemed potentially resectable by radiographic criteria and who underwent DL as part of the staging evaluation before surgery. RESULTS: Of 187 patients (71% men, 80% epithelial) who underwent DL during staging, 76% proceeded to surgery; 22% were unresectable at exploratory thoracotomy and 78% underwent resection (pleurectomy and decortication, 68%; extrapleural pneumonectomy, 32%). Also, 89% had a PET computed tomography (CT), and 11% had a preoperative CT without PET. DL revealed peritoneal disease in 17%. Among patients with pathologically proven disease at DL, 77% had negative PET-CT imaging. Based on the pathologic findings at DL the sensitivity, specificity, positive predictive value, and negative predictive value of PET-CT were 23%, 78%, 17%, and 83%, respectively. The accuracy of PET-CT was 68%. CONCLUSIONS: PET-CT has low sensitivity and diagnostic accuracy to identify peritoneal disease in malignant pleural mesothelioma. DL as part of the preoperative staging defines an important subset of patients with bicavitary disease. We recommend DL as a component of staging before surgery.

Gender Disparity in Referral for Definitive Care of Malignant Pleural Effusions.

BACKGROUND: Gender disparities exist in cancer care. Malignant pleural effusions (MPEs) carry a poor prognosis and are managed by different physicians. This study sought to evaluate referral patterns and gender differences for definitive treatment and outcomes of MPE patients. MATERIALS AND METHODS: Patients diagnosed with MPE from 1999 to 2015 at a quaternary care hospital were retrospectively reviewed to obtain patient history, referral to thoracic surgery for definitive management, and outcomes. Analysis was performed using chi-squared/Fisher's exact test, logistic regression models, and multivariate analysis. RESULTS: 224/686 patients (32.7%) were referred to thoracic surgery. No survival difference existed between referral and nonreferral groups or referred patients who received or did not receive pleurodesis. 405 patients (59.0%) were women. Women were statistically significantly less likely to be referred than men (27.9% versus 39.5%, P = 0.0014). This disparity persisted when comorbidities were controlled for (P = 0.0004) and when gynecologic cancers (e.g., uterine, ovarian, but not including breast; 55 female patients) were excluded from analysis (28.9% versus 39.5%, P = 0.0049). Women had statistically significantly more thoracenteses (3.34 versus 2.19, P < 0.0001) and improved survival compared with males (median survival = 136 d versus 54; P = 0.0004). CONCLUSIONS: Gender disparity exists in referral patterns for definitive management of MPE; women are less likely to be referred than men. Women have longer survival and a greater number of thoracenteses performed, despite a lower referral rate for definitive care. Further research is needed to understand the differences in referral rates and outcomes between men and women.

Positron Emission Tomography 18F-Fluorodeoxyglucose Uptake Correlates with KRAS and EMT Gene Signatures in Operable Esophageal Adenocarcinoma.

BACKGROUND: 18F-fluorodeoxyglucose positron emission tomography is an imaging modality critical to the diagnosis and staging of esophageal cancer. Despite this, the genetic abnormalities associated with increased 18F-fluorodeoxyglucose (FDG)-maximum standardized uptake value (SUVmax) have not been previously explored in esophageal adenocarcinoma. MATERIALS AND METHODS: Treatment-naïve patients, for whom frozen tissue and 18F-fluorodeoxyglucose positron emission tomography data were available, undergoing esophagectomy from 2003 to 2012, were identified. Primary tumor FDG-uptake (SUVmax) was quantified as low (<5), moderate, or high (>10). Genome-wide expression analyses (e.g., microarray) were used to examine gene expression differences associated with FDG-uptake. RESULTS: Eighteen patients with stored positron emission tomography data and tissue were reviewed. Overall survival was similar between patients with high (n = 9) and low (n = 6) FDG-uptake tumors (P = 0.71). Differences in gene expression between tumors with high and low FDG-uptake included enriched expression of various matrix metalloproteinases, extracellular-matrix components, oncogenic signaling members, and PD-L1 (fold-change>2.0, P < 0.05) among the high-FDG tumors. Glycolytic gene expression and pathway involvement were similar between the high- and low-FDG tumor subsets (P = 0.126). Gene ontology analysis of the most differentially expressed genes demonstrated significant upregulation of gene sets associated with extracellular matrix organization and vascular development (P < 0.005). Gene set enrichment analysis further demonstrated associations between FDG-uptake intensity and canonical oncogenic processes, including hypoxia, angiogenesis, KRAS signaling, and epithelial-to-mesenchymal transition (P < 0.001). Interestingly, KRAS expression did not predict worse survival in a larger cohort (n = 104) of esophageal adenocarcinomas (P = 0.64). CONCLUSIONS: These results suggest that elevated FDG-uptake is associated with a variety of oncogenic alterations in operable esophageal adenocarcinoma. These pathways present potential therapeutic targets among tumors exhibiting high FDG-uptake.

18F-FDG PET intensity correlates with a hypoxic gene signature and other oncogenic abnormalities in operable non-small cell lung cancer.

BACKGROUND: 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) is critical for staging non-small-cell lung cancer (NSCLC). While PET intensity carries prognostic significance, the genetic abnormalities associated with increased intensity remain unspecified. METHODS: NSCLC samples (N = 34) from 1999 to 2011 for which PET data were available were identified from a prospectively collected tumor bank. PET intensity was classified as mild, moderate, or intense based on SUVmax measurement or radiology report. Associations between genome-wide expression (RNAseq) and PET intensity were determined. Associations with overall survival were then validated in two external NSCLC cohorts. RESULTS: Overall survival was significantly worse in patients with PET-intense (N = 11) versus mild (N = 10) tumors (p = 0.039). Glycolytic gene expression patterns were markedly similar between intense and mild tumors. Gene ontology analysis demonstrated significant enhancement of cell-cycle and proliferative processes in FDG-intense tumors (p<0.001). Gene set enrichment analysis (GSEA) suggested associations between PET-intensity and canonical oncogenic signaling pathways including MYC, NF-κB, and HIF-1. Using an external cohort of 25 tumors with PET and genomic profiling data, common genes and gene sets were validated for additional study (P<0.05). Of these common gene sets, 20% were associated with hypoxia or HIF-1 signaling. While HIF-1 expression did not correlate with poor survival in the NSCLC validation cohort (N = 442), established targets of hypoxia signaling (PLAUR, ADM, CA9) were significantly associated with poor overall survival. CONCLUSIONS: PET-intensity is associated with a variety of oncogenic alterations in operable NSCLC. Adjuvant targeting of these pathways may improve survival among patients with PET-intense tumors.

Increased Variance in Oral and Gastric Microbiome Correlates With Esophagectomy Anastomotic Leak.

BACKGROUND: Anastomotic leak after esophagectomy remains a significant source of morbidity and mortality. The gastrointestinal (GI) microbiome has been found to play a significant role in tumor oncogenesis and postoperative bowel anastomotic leak. We hypothesized that the GI microbiome could differentiate between esophageal cancer histologies and predict postoperative anastomotic leak. METHODS: A prospective study of esophagectomy patients was performed from May 2013 to August 2014, with the collection of oral saliva, intraoperative esophageal and gastric mucosa, and samples of postoperative infections (neck swab or sputum). The presence and level for each bacterial probe as end points were used to analyze correlations with tumor histology, tumor stage, and presence of postoperative complications by unequal variances t tests for multiple comparisons and principal coordinate analysis. RESULTS: Esophagectomy was successful in 55 of 66 patients who were enrolled. Among those, the diagnosis was adenocarcinoma in 44 (80%) squamous cell carcinoma in (13%), and benign disease in 4 (7%). The 30-day mortality was 1.8% (1 of 55). Complications included anastomotic leak requiring local drainage in 18% (10 of 55) and postoperative pneumonia in 2% (1 of 55). No correlation was noted between GI microbiome flora and tumor histology or tumor stage. A significant difference (p = 0.015) was found when the variance in bacterial composition between the preoperative oral flora was compared with intraoperative gastric flora in patients who had a leak but not in patients with pneumonia. CONCLUSIONS: Patients with anastomotic leaks had increased variance in their preoperative oral and gastric flora. Microbiome analysis could help identify patients at higher risk for leak after esophagectomy.

Overexpression of FAM83H-AS1 indicates poor patient survival and knockdown impairs cell proliferation and invasion via MET/EGFR signaling in lung cancer.

Whole transcriptome analyses of next generation RNA sequencing (RNA-Seq) data from human cancer samples reveled thousands of uncharacterized non-coding RNAs including long non-coding RNA (lncRNA). Recent studies indicated that lncRNAs are emerging as crucial regulators in cancer processes and potentially useful as biomarkers for cancer diagnosis and prognosis. To delineate dysregulated lncRNAs in lung cancer, we analyzed RNA-Seq data from 461 lung adenocarcinomas (LUAD) and 156 normal lung tissues. FAM83H-AS1, one of the top dysregulated lncRNAs, was found to be overexpressed in tumors relative to normal lung and significantly associated with worse patient survival in LUAD. We verified this diagnostic/prognostic potential in an independent cohort of LUAD by qRT-PCR. Cell proliferation, migration and invasion were decreased after FAM83H-AS1 knockdown using siRNAs in lung cancer cells. Flow cytometry analysis indicated the cell cycle was arrested at the G2 phase after FAM83H-AS1 knockdown. Mechanistically, we found that MET/EGFR signaling was regulated by FAM83H-AS1. Our study indicated that FAM83H-AS1 plays an important role in lung tumor progression and may be potentially used as diagnostic/prognostic marker. Further characterization of this lncRNA may provide a novel therapeutic target impacting MET/EGFR signaling.

Non-coding RNA LINC00857 is predictive of poor patient survival and promotes tumor progression via cell cycle regulation in lung cancer.

We employed next generation RNA sequencing analysis to reveal dysregulated long non-coding RNAs (lncRNAs) in lung cancer utilizing 461 lung adenocarcinomas (LUAD) and 156 normal lung tissues from 3 separate institutions. We identified 281 lncRNAs with significant differential-expression between LUAD and normal lung tissue. LINC00857, a top deregulated lncRNAs, was overexpressed in tumors and significantly associated with poor survival in LUAD. knockdown of LINC00857 with siRNAs decreased tumor cell proliferation, colony formation, migration and invasion in vitro, as well as tumor growth in vivo. Overexpression of LINC00857 increased cancer cell proliferation, colony formation and invasion. Mechanistic analyses indicated that LINC00857 mediates tumor progression via cell cycle regulation. Our study highlights the diagnostic/prognostic potential of LINC00857 in LUAD besides delineating the functional and mechanistic aspects of its aberrant disease specific expression and potentially using as a new therapeutic target.

MAP3K3 expression in tumor cells and tumor-infiltrating lymphocytes is correlated with favorable patient survival in lung cancer.

MAP3K3 is involved in both the immune response and in tumor progression. Its potential biological role in vitro in lung cancer cell lines and the association of mRNA/protein expression patterns with clinical outcome of primary lung tumors were investigated in this study. Silencing MAP3K3 using siRNA in lung cancer cell lines resulted in decreased cell proliferation, migration and invasion. These effects were associated with down-regulation of the JNK, p38, AKT, and GSK3ß pathways as determined using phospho-protein and gene expression array analyses. However, MAP3K3 mRNA and protein overexpression in primary lung tumors correlated significantly with favorable patient survival. Gene cluster and pathway analyses of primary tumor datasets indicated that genes positively-correlated with MAP3K3 are significantly involved in immune response rather than the cell cycle regulators observed using in vitro analyses. These results indicate that although MAP3K3 overexpression has an oncogenic role in vitro, in primary lung adenocarcinomas it correlates with an active immune response in the tumor environment that correlates with improved patient survival. MAP3K3 may potentially not only serve as diagnostic/prognostic markers for patients with lung cancer but also provide an indicator for future investigations into immunomodulatory therapies for lung cancer.

Teaching video-assisted thoracic surgery (VATS) lobectomy.

Video-assisted thoracic surgery (VATS) lobectomy has become the standard of care for early stage lung cancer throughout the world. Teaching this complex procedure requires adequate case volume, adequate instrumentation, a committed operating room team and baseline experience with open lobectomy. We outline what key maneuvers and steps are required to teach and learn VATS lobectomy. This is most easily performed as part of a thoracic surgery training program, but with adequate commitment and proctoring, there is no reason experienced open surgeons cannot become proficient VATS surgeons. We provide videos showing the key portions of a subcarinal lymph node dissection, posterior hilar dissection of the right upper lobe, fissureless right middle lobectomy, and fissureless left lower lobectomy. These videos highlight what we feel are important principals in VATS lobectomy, i.e., N2 and N1 lymph node dissection, fissureless techniques, and progressive responsibility of the learner. Current literature in simulation of VATS lobectomy is also outlined as this will be the future of teaching in VATS lobectomy.