Uniportal video-assisted thoracic surgery: segmentectomy versus lobectomy-early outcomes.

OBJECTIVES: To assess the feasibility and safety of uniportal video-assisted thoracoscopic pulmonary segmentectomy compared with lobectomy by studying early postoperative outcomes. METHODS: We included all patients who underwent uniportal segmentectomy and lobectomy between 2017 and 2022 at Karolinska University Hospital. Early clinical outcomes were compared between the uniportal segmentectomy and lobectomy groups. Differences in baseline characteristics were addressed using inverse probability of treatment weighting. RESULTS: A total of 833 patients (232 segmentectomy, 601 lobectomy) were included. The number of uniportal operations increased during the study period. Patients in the segmentectomy and lobectomy groups, respectively, had stage I lung cancer in 65% and 43% of the cases; 97% and 94% had no postoperative complications, the median number of lymph node stations sampled was 4 vs 5, and non-radical microscopic resection occurred in 1.7% vs 1.8%. The drains were removed on postoperative day 1 in 75% vs 72% of the patients following segmentectomy and lobectomy, respectively, and 90% vs 89% were discharged directly home. CONCLUSIONS: Uniportal video-assisted segmentectomy was performed with similar early postoperative clinical results compared with uniportal lobectomy in patients with benign, metastatic or early-stage lung cancer.

Accumulation of tissue-resident natural killer cells, innate lymphoid cells, and CD8+ T cells towards the center of human lung tumors.

Lung cancer is a leading cause of cancer-related death worldwide. Despite recent advances in tissue immunology, little is known about the spatial distribution of tissue-resident lymphocyte subsets in lung tumors. Using high-parameter flow cytometry, we identified an accumulation of tissue-resident lymphocytes including tissue-resident NK (trNK) cells and CD8+ tissue-resident memory T (TRM) cells toward the center of human non-small cell lung carcinomas (NSCLC). Chemokine receptor expression patterns indicated different modes of tumor-infiltration and/or residency between trNK cells and CD8+ TRM cells. In contrast to CD8+ TRM cells, trNK cells and ILCs generally expressed low levels of immune checkpoint receptors independent of location in the tumor. Additionally, granzyme expression in trNK cells and CD8+ TRM cells was highest in the tumor center, and intratumoral CD49a+CD16- NK cells were functional and responded stronger to target cell stimulation than their CD49a- counterparts, indicating functional relevance of trNK cells in lung tumors. In summary, the present spatial mapping of lymphocyte subsets in human NSCLC provides novel insights into the composition and functionality of tissue-resident immune cells, suggesting a role for trNK cells and CD8+ TRM cells in lung tumors and their potential relevance for future therapeutic approaches.

Defining the contractile prostanoid component in hyperosmolar-induced bronchoconstriction in human small airways.

Exercise-induced bronchoconstriction (EIB) is thought to be triggered by increased osmolarity at the airway epithelium. The aim of this study was to define the contractile prostanoid component of EIB, using an ex vivo model where intact segments of bronchi (inner diameter 0.5-2 mm) isolated from human lung tissue and subjected to mannitol. Exposure of bronchial segments to hyperosmolar mannitol evoked a contraction (64.3 ± 3.5 %) which could be prevented either by elimination of mast cells (15.8 ± 4.3 %) or a combination of cysteinyl leukotriene (cysLT1), histamine (H1) and thromboxane (TP) receptor antagonists (11.2 ± 2.3 %). Likewise, when antagonism of TP receptor was exchanged for inhibition of either cyclooxygenase-1 (8 ± 2.5 %), hematopoietic prostaglandin (PG)D synthase (20.7 ± 5.6 %), TXA synthase (14.8 ± 4.9 %), or the combination of the latter two (12.2 ± 4.6 %), the mannitol-induced contraction was prevented, suggesting that the TP-mediated component is induced by PGD2 and TXA2 generated by COX-1 and their respective synthases.

Analysis of human lung mast cells by single cell RNA sequencing.

Mast cells are tissue-resident cells playing major roles in homeostasis and disease conditions. Lung mast cells are particularly important in airway inflammatory diseases such as asthma. Human mast cells are classically divided into the subsets MCT and MCTC, where MCT express the mast cell protease tryptase and MCTC in addition express chymase, carboxypeptidase A3 (CPA3) and cathepsin G. Apart from the disctintion of the MCT and MCTC subsets, little is known about the heterogeniety of human lung mast cells and a deep analysis of their heterogeniety has previously not been performed. We therefore performed single cell RNA sequencing on sorted human lung mast cells using SmartSeq2. The mast cells showed high expression of classical mast cell markers. The expression of several individual genes varied considerably among the cells, however, no subpopulations were detected by unbiased clustering. Variable genes included the protease-encoding transcripts CMA1 (chymase) and CTSG (cathepsin G). Human lung mast cells are predominantly of the MCT subset and consistent with this, the expression of CMA1 was only detectable in a small proportion of the cells, and correlated moderately to CTSG. However, in contrast to established data for the protein, CPA3 mRNA was high in all cells and the correlation of CPA3 to CMA1 was weak.

Cysteinyl-maresin 3 inhibits IL-13 induced airway hyperresponsiveness through alternative activation of the CysLT1 receptor.

BACKGROUND: Cysteinyl-maresins, also known as maresin-conjugates in tissue regeneration (MCTRs), are recently discovered lipid mediators proposed to reduce airway inflammation. OBJECTIVE: To investigate the influence of MCTRs on IL-13-induced airway hyperresponsiveness in isolated human and mice airways. METHODS: Before responsiveness to contractile agonists were assessed in myographs, human small bronchi were cultured for 2 days and mouse tracheas were cultured for 1-4 days. During the culture procedure airways were exposed to interleukin (IL)-13 in the presence or absence of MCTRs. Signalling mechanisms were explored using pharmacologic agonists and antagonists, and genetically modified mice. RESULTS: IL-13 treatment increased contractions to histamine, carbachol and leukotriene D4 (LTD4) in human small bronchi, and to 5-hydroxytryptamine (5-HT) in mouse trachea. In both preparations, co-incubation of the explanted tissues with MCTR3 reduced the IL-13 induced enhancement of contractions. In mouse trachea, this inhibitory effect of MCTR3 was blocked by three different CysLT1 receptor antagonists (montelukast, zafirlukast and pobilukast) during IL-13 exposure. Likewise, MCTR3 failed to reduce the IL-13-induced 5-HT responsiveness in mice deficient of the CysLT1 receptor. However, co-incubation with the classical CysLT1 receptor agonist LTD4 did not alter the IL-13-induced 5-HT hyperreactivity. CONCLUSIONS: MCTR3, but not LTD4, decreased the IL-13-induced airway hyperresponsiveness by activation of the CysLT1 receptor. The distinct actions of the two lipid mediators on the CysLT1 receptor suggest an alternative signalling pathway appearing under inflammatory conditions, where this new action of MCTR3 implicates potential to inhibit airway hyperresponsiveness in asthma.

Sphingomyelinase activity promotes atrophy and attenuates force in human muscle fibres and is elevated in heart failure patients.

BACKGROUND: Activation of sphingomyelinase (SMase) as a result of a general inflammatory response has been implicated as a mechanism underlying disease-related loss of skeletal muscle mass and function in several clinical conditions including heart failure. Here, for the first time, we characterize the effects of SMase activity on human muscle fibre contractile function and assess skeletal muscle SMase activity in heart failure patients. METHODS: The effects of SMase on force production and intracellular Ca2+ handling were investigated in single intact human muscle fibres. Additional mechanistic studies were performed in single mouse toe muscle fibres. RNA sequencing was performed in human muscle bundles exposed to SMase. Intramuscular SMase activity was measured from heart failure patients (n = 61, age 69 ± 0.8 years, NYHA III-IV, ejection fraction 25 ± 1.0%, peak VO2 14.4 ± 0.6 mL × kg × min) and healthy age-matched control subjects (n = 10, age 71 ± 2.2 years, ejection fraction 60 ± 1.2%, peak VO2 25.8 ± 1.1 mL × kg × min). SMase activity was related to circulatory factors known to be associated with progression and disease severity in heart failure. RESULTS: Sphingomyelinase reduced muscle fibre force production (-30%, P < 0.05) by impairing sarcoplasmic reticulum (SR) Ca2+ release (P < 0.05) and reducing myofibrillar Ca2+ sensitivity. In human muscle bundles exposed to SMase, RNA sequencing analysis revealed 180 and 291 genes as up-regulated and down-regulated, respectively, at a FDR of 1%. Gene-set enrichment analysis identified 'proteasome degradation' as an up-regulated pathway (average fold-change 1.1, P = 0.008), while the pathway 'cytoplasmic ribosomal proteins' (average fold-change 0.8, P < 0.0001) and factors involving proliferation of muscle cells (average fold-change 0.8, P = 0.0002) where identified as down-regulated. Intramuscular SMase activity was ~20% higher (P < 0.05) in human heart failure patients than in age-matched healthy controls and was positively correlated with markers of disease severity and progression, and with several circulating inflammatory proteins, including TNF-receptor 1 and 2. In a longitudinal cohort of heart failure patients (n = 6, mean follow-up time 2.5 ± 0.2 years), SMase activity was demonstrated to increase by 30% (P < 0.05) with duration of disease. CONCLUSIONS: The present findings implicate activation of skeletal muscle SMase as a mechanism underlying human heart failure-related loss of muscle mass and function. Moreover, our findings strengthen the idea that SMase activation may underpin disease-related loss of muscle mass and function in other clinical conditions, acting as a common patophysiological mechanism for the myopathy often reported in diseases associated with a systemic inflammatory response.

Expansions of adaptive-like NK cells with a tissue-resident phenotype in human lung and blood.

Human adaptive-like "memory" CD56dimCD16+ natural killer (NK) cells in peripheral blood from cytomegalovirus-seropositive individuals have been extensively investigated in recent years and are currently explored as a treatment strategy for hematological cancers. However, treatment of solid tumors remains limited due to insufficient NK cell tumor infiltration, and it is unknown whether large expansions of adaptive-like NK cells that are equipped for tissue residency and tumor homing exist in peripheral tissues. Here, we show that human lung and blood contains adaptive-like CD56brightCD16- NK cells with hallmarks of tissue residency, including expression of CD49a. Expansions of adaptive-like lung tissue-resident NK (trNK) cells were found to be present independently of adaptive-like CD56dimCD16+ NK cells and to be hyperresponsive toward target cells. Together, our data demonstrate that phenotypically, functionally, and developmentally distinct subsets of adaptive-like NK cells exist in human lung and blood. Given their tissue-related character and hyperresponsiveness, human lung adaptive-like trNK cells might represent a suitable alternative for therapies targeting solid tumors.

Tissue-specific transcriptional imprinting and heterogeneity in human innate lymphoid cells revealed by full-length single-cell RNA-sequencing.

The impact of the microenvironment on innate lymphoid cell (ILC)-mediated immunity in humans remains largely unknown. Here we used full-length Smart-seq2 single-cell RNA-sequencing to unravel tissue-specific transcriptional profiles and heterogeneity of CD127+ ILCs across four human tissues. Correlation analysis identified gene modules characterizing the migratory properties of tonsil and blood ILCs, and signatures of tissue-residency, activation and modified metabolism in colon and lung ILCs. Trajectory analysis revealed potential differentiation pathways from circulating and tissue-resident naïve ILCs to a spectrum of mature ILC subsets. In the lung we identified both CRTH2+ and CRTH2- ILC2 with lung-specific signatures, which could be recapitulated by alarmin-exposure of circulating ILC2. Finally, we describe unique TCR-V(D)J-rearrangement patterns of blood ILC1-like cells, revealing a subset of potentially immature ILCs with TCR-δ rearrangement. Our study provides a useful resource for in-depth understanding of ILC-mediated immunity in humans, with implications for disease.

Immunoprofiling Reveals Novel Mast Cell Receptors and the Continuous Nature of Human Lung Mast Cell Heterogeneity.

Background: Immunohistochemical analysis of granule-associated proteases has revealed that human lung mast cells constitute a heterogeneous population of cells, with distinct subpopulations identified. However, a systematic and comprehensive analysis of cell-surface markers to study human lung mast cell heterogeneity has yet to be performed. Methods: Human lung mast cells were obtained from lung lobectomies, and the expression of 332 cell-surface markers was analyzed using flow cytometry and the LEGENDScreen™ kit. Markers that exhibited high variance were selected for additional analyses to reveal whether they were correlated and whether discrete mast cell subpopulations were discernable. Results: We identified the expression of 102 surface markers on human lung mast cells, 23 previously not described on mast cells, of which several showed high continuous variation in their expression. Six of these markers were correlated: SUSD2, CD49a, CD326, CD34, CD66 and HLA-DR. The expression of these markers was also correlated with the size and granularity of mast cells. However, no marker produced an expression profile consistent with a bi- or multimodal distribution. Conclusions: LEGENDScreen analysis identified more than 100 cell-surface markers on mast cells, including 23 that, to the best of our knowledge, have not been previously described on human mast cells. The comprehensive expression profiling of the 332 surface markers did not identify distinct mast cell subpopulations. Instead, we demonstrate the continuous nature of human lung mast cell heterogeneity.

Erratum to video-assisted thoracoscopic versus open thoracotomy lobectomy: a Swedish nationwide cohort study.

[This corrects the article DOI: 10.21037/jtd.2018.05.177.].

Impaired sarcoplasmic reticulum Ca2+ release is the major cause of fatigue-induced force loss in intact single fibres from human intercostal muscle.

KEY POINTS: Changes in intramuscular Ca2+ handling contribute to development of fatigue and disease-related loss of muscle mass and function. To date, no data on human intact living muscle fibres have been described. We manually dissected intact single fibres from human intercostal muscle and simultaneously measured force and myoplasmic free [Ca2+ ] at physiological temperature. Based on their fatigue resistance, two distinct groups of fibres were distinguished: fatigue sensitive and fatigue resistant. Force depression in fatigue and during recovery was due to impaired sarcoplasmic reticulum Ca2+ release in both groups of fibres. Acidification did not affect force production in unfatigued fibres and did not affect fatigue development in fatigue-resistant fibres. The current study provides novel insight into the mechanisms of fatigue in human intercostal muscle. ABSTRACT: Changes in intracellular Ca2+ handling of individual skeletal muscle fibres cause a force depression following physical activity and are also implicated in disease-related loss of function. The relation of intracellular Ca2+ handling with muscle force production and fatigue tolerance is best studied in intact living single fibres that allow continuous measurements of force and myoplasmic free [Ca2+ ] during repeated contractions. To this end, manual dissections of human intercostal muscle biopsies were performed to isolate intact single fibres. Based on the ability to maintain tetanic force at >40% of the initial value during 500 fatiguing contractions, fibres were classified as either fatigue sensitive or fatigue resistant. Following fatigue all fibres demonstrated a marked reduction in sarcoplasmic reticulum Ca2+ release, while myofibrillar Ca2+ sensitivity was either unaltered or increased. In unfatigued fibres, acidosis caused a reduction in myofibrillar Ca2+ sensitivity that was offset by increased tetanic myoplasmic free [Ca2+ ] so that force remained unaffected. Acidification did not affect the fatigue tolerance of fatigue-resistant fibres, whereas uncertainties remain whether or not fatigue-sensitive fibres were affected. Following fatigue, a prolonged force depression at preferentially low-frequency stimulation was evident in fatigue-sensitive fibres and this was caused exclusively by an impaired sarcoplasmic reticulum Ca2+ release. We conclude that impaired sarcoplasmic reticulum Ca2+ release is the predominant mechanism of force depression both in the development of, and recovery from, fatigue in human intercostal muscle.

IL-13 and IL-4, but not IL-5 nor IL-17A, induce hyperresponsiveness in isolated human small airways.

BACKGROUND: Specific inflammatory pathways are indicated to contribute to severe asthma, but their individual involvement in the development of airway hyperresponsiveness remains unexplored. OBJECTIVE: This experimental study in human small bronchi aimed to provide insight into which of the type 2 and type 17 cytokines cause hyperresponsiveness of airway smooth muscle. METHODS: Explanted small bronchi isolated from human lung tissue and human airway smooth muscle cells were treated for 2 and 1 day(s), respectively, with 100 ng/mL of IL-4, IL-5, IL-13, or IL-17A, and contractile responses, Ca2+ mobilization, and receptor expression were assessed. RESULTS: Treatment with IL-13 increased the potency of histamine, carbachol, and leukotriene D4 as contractile agonists. IL-4, but not IL-5 or IL-17A, also increased the potency of histamine. In human airway smooth muscle cells, IL-13 and IL-4, but not IL-5 and IL-17A, enhanced the histamine-induced Ca2+ mobilization that was accompanied with increased mRNA expression of histamine H1 and cysteinyl leukotriene CysLT1 receptors. RNA sequencing of isolated bronchi confirmed the IL-13-mediated upregulation of H1 and CysLT1 receptors, without showing an alteration of muscarinic M3 receptors. Dexamethasone had no effects on IL-13-induced hyperresponsiveness in human bronchi, the increased Ca2+ mobilization, or the enhanced receptor expression. In contrast, antagonism of the common receptor for IL-13 and IL-4 by the biologic dupilumab prevented the effects of both IL-13 and IL-4 in human bronchi and human airway smooth muscle cells. CONCLUSIONS: The glucocorticoid-insensitive hyperrresponsiveness in isolated human airways induced by IL-13 and IL-4 provides further evidence that the IL-4Rα pathway should be targeted as a new strategy for the treatment of airway hyperresponsiveness in asthma.

Unique transcriptional and protein-expression signature in human lung tissue-resident NK cells.

Human lung tissue-resident NK cells (trNK cells) are likely to play an important role in host responses towards viral infections, inflammatory conditions and cancer. However, detailed insights into these cells are still largely lacking. Here we show, using RNA sequencing and flow cytometry-based analyses, that subsets of human lung CD69+CD16- NK cells display hallmarks of tissue-residency, including high expression of CD49a, CD103, and ZNF683, and reduced expression of SELL, S1PR5, and KLF2/3. CD49a+CD16- NK cells are functionally competent, and produce IFN-γ, TNF, MIP-1ß, and GM-CSF. After stimulation with IL-15, they upregulate perforin, granzyme B, and Ki67 to a similar degree as CD49a-CD16- NK cells. Comparing datasets from trNK cells in human lung and bone marrow with tissue-resident memory CD8+ T cells identifies core genes co-regulated either by tissue-residency, cell-type or location. Together, our data indicate that human lung trNK cells have distinct features, likely regulating their function in barrier immunity.

Mannitol triggers mast cell-dependent contractions of human small bronchi and prostacyclin bronchoprotection.

BACKGROUND: Clinical research supports that exercise-induced bronchoconstriction (EIB) is caused by hyperosmolar triggering of mast cells. The reaction can be mimicked by inhalation of mannitol, but it has paradoxically previously not been possible to replicate this mode of action of mannitol in isolated airways. OBJECTIVE: We sought to establish an ex vivo model of EIB in human small bronchi. METHODS: Small bronchi (inner diameter, 0.5-2 mm) from macroscopically healthy human lung tissue were obtained from 48 patients and mounted in organ baths. Contractions and mediator release were analyzed after challenge with hyperosmolar mannitol (850 mOsm). RESULTS: Ten minutes of exposure to mannitol caused a small initial contraction (12% ± 1% of maximum) that was followed by a second and much larger contraction (maximum effect [Emax], 47% ± 5%) when mannitol was washed out. The mast cell stabilizer cromolyn reduced the second contraction (Emax, 27% ± 3%). Furthermore, this main contraction was abolished by the combination of antagonists of histamine and cysteinyl leukotrienes in the presence of indomethacin. Mannitol increased the release of the mast cell mediators histamine (9.0-fold), cysteinyl leukotrienes (4.5-fold), and prostaglandin (PG) D2 (5.4-fold), as well as PGE2 (6.3-fold) and the prostacyclin metabolite 6-keto PGF1α (5.7-fold). In contrast, indomethacin alone enhanced the bronchoconstriction (Emax, 68% ± 6%). Likewise, receptor antagonists for PGE2 (EP2 and EP4) and prostacyclin (IP) also enhanced the mannitol-induced bronchoconstriction (Emax, 67% ± 5%, 66% ± 4%, and 68% ± 3%, respectively). In bronchi precontracted by carbachol, the IP receptor agonist cicaprost induced profound relaxation. CONCLUSION: This new protocol established an in vitro model for studies of EIB in isolated human bronchi. The IP receptor might be a new target for asthma treatment.

Influenza A Virus Infection Induces Hyperresponsiveness in Human Lung Tissue-Resident and Peripheral Blood NK Cells.

NK cells in the human lung respond to influenza A virus- (IAV-) infected target cells. However, the detailed functional capacity of human lung and peripheral blood NK cells remains to be determined in IAV and other respiratory viral infections. Here, we investigated the effects of IAV infection on human lung and peripheral blood NK cells in vitro and ex vivo following clinical infection. IAV infection of lung- and peripheral blood-derived mononuclear cells in vitro induced NK cell hyperresponsiveness to K562 target cells, including increased degranulation and cytokine production particularly in the CD56brightCD16- subset of NK cells. Furthermore, lung CD16- NK cells showed increased IAV-mediated but target cell-independent activation compared to CD16+ lung NK cells or total NK cells in peripheral blood. IAV infection rendered peripheral blood NK cells responsive toward the normally NK cell-resistant lung epithelial cell line A549, indicating that NK cell activation during IAV infection could contribute to killing of surrounding non-infected epithelial cells. In vivo, peripheral blood CD56dimCD16+ and CD56brightCD16- NK cells were primed during acute IAV infection, and a small subset of CD16-CD49a+CXCR3+ NK cells could be identified, with CD49a and CXCR3 potentially promoting homing to and tissue-retention in the lung during acute infection. Together, we show that IAV respiratory viral infections prime otherwise hyporesponsive lung NK cells, indicating that both CD16+ and CD16- NK cells including CD16-CD49a+ tissue-resident NK cells could contribute to host immunity but possibly also tissue damage in clinical IAV infection.

Uniportal versus multiportal video-assisted thoracic surgery for lung cancer.

BACKGROUND: Video-assisted thoracic surgery (VATS) lobectomy is the recommended surgical approach for patients with stage I lung cancer. Whether a multiportal or a uniportal approach is preferable remains unclear. The aim of this study was to evaluate the safety of implementing uniportal VATS lobectomy into the treatment program of lung cancer patients. METHODS: We used the national quality register for general thoracic surgery in Sweden and included all patients who underwent VATS lobectomy for lung cancer at the Karolinska University Hospital between 2016-2018. Early postoperative complications were compared in patients undergoing uniportal (n=122) and multiportal (n=211) VATS lobectomy for lung cancer. Inverse probability of treatment weighting and standardized mean differences were used to limit differences in baseline characteristics and to assess balance after weighting. RESULTS: The proportion of uniportal VATS lobectomies increased during the study period and the conversion rates declined significantly. Baseline characteristics were similar in the two groups with the exception of a higher percentage of patients without any comorbidity in the uniportal group (59.8% vs. 44.5%, P=0.010). After inverse probability of treatment weighting the groups were well balanced. Postoperative complications were rare regardless of surgical approach, 94% in both groups had no complications. The 30-day mortality and overall survival at 1 year was 0% and 97% in the uniportal group, and 0.5% and 98% in the multiportal group (P=0.71). Patients undergoing uniportal VATS lobectomy were discharged directly to home to a higher extent than multiportal VATS patients (76.2% vs. 62.1%, P=0.008). CONCLUSIONS: We found that uniportal VATS lobectomy was feasible and safe, and might entail advantages in terms of a faster recovery after surgery as compared to multiportal VATS lobectomy in patients with lung cancer.

An Optimized Protocol for the Isolation and Functional Analysis of Human Lung Mast Cells.

Background: Mast cells are tissue-resident inflammatory cells defined by their high granularity and surface expression of the high-affinity IgE receptor, FcεRI, and CD117/KIT, the receptor for stem cell factor (SCF). There is a considerable heterogeneity among mast cells, both phenotypically and functionally. Human mast cells are generally divided into two main subtypes based on their protease content; the mucosa-associated MCT (tryptase positive and chymase negative mast cell) and the connective tissue associated-residing MCTC (tryptase and chymase positive mast cell). Human lung mast cells exhibit heterogeneity in terms of cellular size, expression of cell surface receptors, and secreted mediators. However, knowledge about human lung mast cell heterogeneity is restricted to studies using immunohistochemistry or purified mast cells. Whereas the former is limited by the number of cellular markers that can be analyzed simultaneously, the latter suffers from issues related to cell yield. Aim: To develop a protocol that enables isolation of human lung mast cells at high yields for analysis of functional properties and detailed analysis using single-cell based analyses of protein (flow cytometry) or RNA (RNA-sequencing) expression. Methods: Mast cells were isolated from human lung tissue by a sequential combination of washing, enzymatic digestion, mechanical disruption, and density centrifugation using Percoll (WEMP). As a comparison, we also isolated mast cells using a conventional enzyme-based protocol. The isolated cells were analyzed by flow cytometry. Results: We observed a significant increase in the yield of total human lung CD45+ immune cells and an even more pronounced increase in the yield of CD117+ mast cells with the WEMP protocol in comparison to the conventional protocols. In contrast, the frequency of the rare lymphocyte subset innate lymphoid cells group 2 (ILC2) did not differ between the two methods. Conclusion: The described WEMP protocol results in a significant increase in the yield of human lung mast cells compared to a conventional protocol. Additionally, the WEMP protocol enables simultaneous isolation of different immune cell populations such as lymphocytes, monocytes, and granulocytes while retaining their surface marker expression that can be used for advanced single-cell analyses including multi-color flow cytometry and RNA-sequencing.

Surgery for pulmonary metastases from colorectal cancer: survival and prognostic factors.

BACKGROUND: This study aimed to describe overall survival following pulmonary metastasectomy for colorectal cancer (CRC) in Sweden, and to assess the discrimination of a recently proposed risk prediction model. METHODS: Individual-level data of 756 patients who underwent resection of pulmonary metastases from CRC between 2009 and 2015 were obtained from ThoR, a Swedish national quality register for thoracic surgery. We classified patients into three risk categories according to the number of preoperative risk factors [age, disease-free interval (DFI), presence of extrathoracic lesions, number of pulmonary metastases] established in a prior study. We estimated the hazard ratios (HRs) and 95% confidence interval (CI) by Cox regression and the restricted mean survival time difference as group contrast measures. RESULTS: During a median follow-up time of 2.9 years, 35% (268/756) patients died. At 5 years, overall survival was 56% (95% CI: 51-60%). In a Cox regression model with risk category as the only independent variable, the HR for all-cause mortality was 1.94 (95% CI: 1.38-2.72, P<0.001) and 4.35 (95% CI: 2.49-7.62, P<0.001) in the moderate- (n=558) and high-risk categories (n=32), respectively, versus the low-risk category (n=166). At 5 years, the differences in restricted mean survival time were 6 months (P<0.001) and 1.5 years (P<0.001) in the moderate- and high-risk categories, respectively, versus the low-risk category. CONCLUSIONS: Five-year survival after surgery for pulmonary metastases from CRC in Sweden was similar or higher compared with contemporary reports. A prognostic model, initially developed in Japanese patients, had excellent discrimination in an external validation cohort of Swedish patients.

Video-assisted thoracoscopic versus open thoracotomy lobectomy: a Swedish nationwide cohort study.

BACKGROUND: The aim of this nationwide observational cohort study was to investigate the early postoperative complications and long-term survival following video-assisted thoracoscopic surgery (VATS) lobectomy compared to open thoracotomy lobectomy for early stage non-small cell lung cancer (NSCLC). METHODS: We used the Swedish national quality register for general thoracic surgery and included all patients who underwent lobectomy for NSCLC during 2012-2015. We compared postoperative complications and long-term survival in patients who underwent VATS lobectomy at our institution to patients who underwent open lobectomy at the other seven hospitals in Sweden. We used inverse probability of treatment weighting to limit differences in baseline characteristics between the groups and used standardized mean differences to assess balance after weighting. RESULTS: We included 1,601 patients who underwent open (n=1,316) or VATS (n=285) lobectomy for NSCLC. The mean age was 67.7 years in both groups and comorbidities were well balanced, but the open thoracotomy group had a higher proportion of patients with more advanced cancer stage. After weighting, all baseline characteristics were well balanced. Most patients (84%) did not have postoperative complications; 83% vs. 86% in the open and VATS group, respectively (P=0.41). The 30- and 90-day mortality was 0.7% vs. 0.3% (P=0.38) and 1.7% vs. 0.3% (P=0.09) in the open thoracotomy and VATS group, respectively. There were significantly more transfusions (5.0% vs. 1.4%, P=0.008) and pneumonia (5.5% vs. 0.6%, P=0.002) in the in the open thoracotomy and VATS group, respectively. The overall survival at 1 and 5 years was 92% vs. 97% and 63% vs. 78% in the open thoracotomy and VATS group, respectively; HR (95% CI): 0.47 (0.33-0.68). CONCLUSIONS: We found less postoperative complications and better long-term survival following VATS lobectomy compared to open thoracotomy lobectomy for NSCLC. The implementation of a VATS lobectomy program did not compromise patient safety or the oncological efficacy.