Depletion of Airway Submucosal Glands and TP63+KRT5+ Basal Cells in Obliterative Bronchiolitis.

RATIONALE: Obliterative bronchiolitis (OB) is a major cause of mortality after lung transplantation. Depletion of airway stem cells (SCs) may lead to fibrosis in OB. OBJECTIVES: Two major SC compartments in airways are submucosal glands (SMGs) and surface airway p63 (also known as TP63 [tumor protein 63])-positive/K5 (also known as KRT5 [keratin 5])-positive basal cells (BCs). We hypothesized that depletion of these SC compartments occurs in OB. METHODS: Ferret orthotopic left lung transplants were used as an experimental model of OB, and findings were corroborated in human lung allografts. Morphometric analysis was performed in ferret and human lungs to evaluate the abundance of SMGs and changes in the expression of phenotypic BC markers in control, lymphocytic bronchiolitis, and OB airways. The abundance and proliferative capacity of proximal and distal airway SCs was assessed using a clonogenic colony-forming efficiency assay. MEASUREMENTS AND MAIN RESULTS: Ferret allografts revealed significant loss of SMGs with development of OB. A progressive decline in p63+/K5+ and increase in K5+/K14+ and K14+ BC phenotypes correlated with the severity of allograft rejection in large and small ferret airways. The abundance and proliferative capacity of basal SCs in large allograft airways declined with severity of OB, and there was complete ablation of basal SCs in distal OB airways. Human allografts mirrored phenotypic BC changes observed in the ferret model. CONCLUSIONS: SMGs and basal SC compartments are depleted in large and/or small airways of lung allografts, and basal SC proliferative capacity declines with progression of disease and phenotypic changes. Global airway SC depletion may be a mechanism for pulmonary allograft failure.

Idiopathic hyperammonemia after solid organ transplantation: Primarily a lung problem? A single-center experience and systematic review.

BACKGROUND: Idiopathic hyperammonemia syndrome (IHS) is an uncommon, often deadly complication of solid organ transplantation. IHS cases in solid organ transplantation seem to occur predominantly in lung transplant (LTx) recipients. However, to the best of our knowledge, the occurrence of IHS has not been systematically evaluated. We set out to identify all reported cases of IHS following nonliver solid organ transplantations. METHODS: Retrospective review of our institutional experience and systematic review of the literature. RESULTS: At our institution six cases (of 844 nonliver solid organ transplants) of IHS were identified: five occurred following LTx (incidence 3.9% [lung] vs 0.1% [nonlung], P=.004). In the systematic review, 16 studies met inclusion criteria, reporting on 32 cases of IHS. The majority of IHS cases in the literature (81%) were LTx-recipients. The average peak reported ammonia level was 1039 µmol/L occurring on average 14.7 days post-transplant. Mortality in previously reported IHS cases was 69%. A single-center experience suggested that, in addition to standard treatment for hyperammonemia, early initiation of high intensity hemodialysis to remove ammonia was associated with increased survival. In the systematic review, mortality was 40% (four of 10) with intermittent hemodialysis, 75% (nine of 12) with continuous veno-venous hemodialysis, and 100% in six subjects that did not receive renal replacement to remove ammonia. Three reports identified infection with urease producing organisms as a possible etiology of IHS. CONCLUSION: IHS is a rare but often fatal complication that primarily affects lung transplant recipients within the first 30 days.

Perioperative single-site veno-venous extracorporeal CO2 removal for minimally invasive giant bulla resection.

Giant pulmonary bullae are rare and surgical management of patients with severe emphysema and advanced chronic obstructive lung disease (COPD) presenting with giant bullae can be very challenging. Previously, perioperative, two-site, high-flow, veno-venous extracorporeal membrane oxygenation (ECMO) was successfully utilized during giant bulla resection. Here we report the perioperative application of single-site, low-flow extracorporeal CO2 removal (ECCO2R) for minimally invasive thoracoscopic giant bulla resection. This approach of low-flow, veno-venous ECCO2R, which is less invasive than conventional ECLS approaches, has enabled the safe performance of surgery and facilitated protective intraoperative single-lung ventilation while avoiding possible complications of aggressive mechanical ventilation.

Low molecular weight hyaluronan activates cytosolic phospholipase A2α and eicosanoid production in monocytes and macrophages.

Hyaluronan (HA) is the major glycosaminoglycan in the extracellular matrix. During inflammation, there is an increased breakdown of HA, resulting in the accumulation of low molecular weight (LMW) HA and activation of monocytes and macrophages. Eicosanoids, derived from the cytosolic phospholipase A2 group IVA (cPLA2α) activation, are potent lipid mediators also attributed to acute and chronic inflammation. The aim of this study was to determine the effect of LMW HA on cPLA2α activation, arachidonic acid (AA) release, and subsequent eicosanoid production and to examine the receptors and downstream mechanisms involved in these processes in monocytes and differently polarized macrophages. LMW HA was a potent stimulant of AA release in a time- and dose-dependent manner, induced cPLA2α, ERK1/2, p38, and JNK phosphorylation, as well as activated COX2 expression and prostaglandin (PG) E2 production in primary human monocytes, murine RAW 264.7, and wild-type bone marrow-derived macrophages. Specific cPLA2α inhibitor blocked HA-induced AA release and PGE2 production in all of these cells. Using CD44, TLR4, TLR2, MYD88, RHAMM or STAB2 siRNA-transfected macrophages and monocytes, we found that AA release, cPLA2α, ERK1/2, p38, and JNK phosphorylation, COX2 expression, and PGE2 production were activated by LMW HA through a TLR4/MYD88 pathway. Likewise, PGE2 production and COX2 expression were blocked in Tlr4(-/-) and Myd88(-/-) mice, but not in Cd44(-/-) mice, after LMW HA stimulation. Moreover, we demonstrated that LMW HA activated the M1 macrophage phenotype with the unique cPLA2α/COX2(high) and COX1/ALOX15/ALOX5/LTA4H(low) gene and PGE2/PGD2/15-HETE(high) and LXA4(low) eicosanoid profile. These findings reveal a novel link between HA-mediated inflammation and lipid metabolism.

Diagnostic value of pleural fluid obtained from a chest tube collection system.

BACKGROUND: Pleural fluid is typically drawn directly from the pleural space for diagnostic studies, but occasionally analyses are desired when a chest tube is already in place and a traditional approach is not feasible. The diagnostic value of analyzing fluid samples obtained from the pleural fluid collection system after chest tube insertion is unknown. METHODS: We performed a prospective observational study of patients in whom chest tube placement was planned for clinical indications. Diagnostic studies were performed on fluid obtained from the pleural space at the time of tube insertion and then repeated 2, 6, and 24 h later on samples obtained from the fluid collection system. RESULTS: Fifty-five percent of the 23 effusions studied met light's criteria for exudate at baseline. Lactate dehydrogenase (LDH) varied considerably over time from baseline measures with only 25 % of measures at 24 h falling within 25 % of baseline levels. The sensitivity for exudate by LDH remained 100 % with poor specificity ranging 50-69 % with repeat measures. Total protein exhibited less variability with 85 % of measures at 24 h falling within 25 % of baseline measure. Sensitivity and specificity at 24 h were 88 and 82 %, respectively. Repeat measures of cholesterol, albumin, and triglycerides generally correlated well (Spearman's rho > 0.90) with baseline values. Measures of glucose and cell counts varied considerably from baseline. CONCLUSIONS: Analysis of pleural fluid from a chest tube collection system is feasible and can provide useful diagnostic information. Practitioners should consider the test characteristics of each measure when interpreting samples obtained.

Extended thymectomy including lung-sparing pleurectomy for the treatment of thymic malignancies with pleural spread.

OBJECTIVE: To investigate the outcome of extended thymectomy including lung-sparing pleurectomy (extended surgery) in primary clinically advanced Masaoka-Koga stage IVa thymic malignancies. PATIENTS AND METHODS: Thirteen patients diagnosed with thymic malignancies at primary clinically Masaoka-Koga stage IVa were retrospectively analyzed between January 2000 and December 2012 at the Department of Thoracic Surgery, Dr. Horst Schmidt Klinik, Wiesbaden. Chi-square tests, Kaplan-Meier analyses, log-rank tests, and Cox regression analyses were used to estimate survival and determine prognosticators of survival. RESULTS: World Health Organization (WHO) classification were type C (n = 6), type B3 (n = 5), and type AB (n = 2), respectively. Nine patients underwent extended surgery. Morbidity was observed in three patients (33%). Mortality occurred in one patient. Four patients (31%) were unresectable at the time of surgery and underwent chemoradiation. Despite the clinically staging, five patients had lymph node metastases and thus pathologic Masaoka-Koga stage IVb. Median survival (MS) for all patients was 49 months. Extended surgery (MS 89 months) was associated with prolonged survival compared with patients who underwent only chemoradiation (MS 5 months). Stage migration due to lymph node metastases, WHO-classification type C, and T3/4-status were associated with inferior survival in the univariate analysis. Extended surgery remained the only independent significant prognosticator in the multivariate analysis. CONCLUSION: Extended surgery within multimodality treatments might offer survival advantage for advanced thymic malignancies with pleural spread. Patients with lymph node metastases and WHO classification type C might be at high risk of unresectability.

The fish oil ingredient, docosahexaenoic acid, activates cytosolic phospholipase A2 via GPR120 receptor to produce prostaglandin E2 and plays an anti-inflammatory role in macrophages.

Docosahexaenoic acid (DHA) is one of the major ingredients of fish oil and has been reported to have anti-inflammatory properties mediated through the GPR120 receptor. Whether cytosolic phospholipase A2 (cPLA2 ) and lipid mediators produced from cPLA2 activation are involved in the anti-inflammatory role of DHA in macrophages has not been reported. We report here that DHA and the GPR120 agonist, GW9508, activate cPLA2 and cyclooxygenase 2 (COX-2), and cause prostaglandin E2 (PGE2) release in a murine macrophage cell line RAW264.7 and in human primary monocyte-derived macrophages. DHA and GW9508 activate cPLA2 via GPR120 receptor, G protein Gαq and scaffold protein ß-arrestin 2. Extracellular signal-regulated kinase 1/2 activation is involved in DHA- and GW9508-induced cPLA2 activation, but not p38 mitogen-activated protein kinase. The anti-inflammatory role of DHA and GW9508 is in part via activation of cPLA2 , COX-2 and production of PGE2 as a cPLA2 inhibitor or a COX-2 inhibitor partially reverses the DHA- and GW9508-induced inhibition of lipopolysaccharide-induced interleukin-6 secretion. The cPLA2 product arachidonic acid and PGE2 also play an anti-inflammatory role. This effect of PGE2 is partially through inhibition of the nuclear factor-κB signalling pathway and through the EP4 receptor of PGE2 because an EP4 inhibitor or knock-down of EP4 partially reverses DHA inhibition of lipopolysaccharide-induced interleukin-6 secretion. Hence, DHA has an anti-inflammatory effect partially through induction of PGE2.

Changes in microRNA and mRNA expression with differentiation of human bronchial epithelial cells.

We studied the changes in expression of microRNAs (miRNAs or miRs) and mRNA in normal human bronchial epithelial cells as they differentiate from an undifferentiated monolayer to a differentiated pseudostratified epithelium after 28 days of air-liquid interface (ALI) culture. After 28 days in ALI, the epithelial cells differentially expressed basal, ciliated, and goblet cell markers. Using Affymetrix microarrays, 20 human miRNAs were found to be up-regulated, whereas 35 miRNAs were found to be down-regulated in differentiated cells compared with undifferentiated cells. An analysis of changes in global mRNA expression revealed that 1,201 probe sets demonstrated an 8-fold change (FC) or greater at Day 28 of ALI culture. Of these, 816 were up-regulated and 385 were down-regulated. With differentiation, miR-449a increased (FC, 38.15), and was related to changes in mRNA for cell division cycle 25 homolog A (FC, 0.11). MiR-455 decreased (FC, 0.12) and was related to changes in mRNA for the epithelial cell marker, mucin 1 (FC, 136). Transfection with anti-miR-449 or miR-455-3p resulted in changes in target protein expression (cell division cycle 25 homolog A and mucin 1, respectively), whereas transfection with reporter genes with 3'-untranslated regions of these targets confirmed control of expression through that structure. Therefore, changes in specific miRNAs during human airway epithelial cell differentiation control gene and protein expression important for differentiation.

Management of two circulations in a COVID-19 patient with secondary superinfection.

Optimal oxygenation in the intensive care unit requires adequate pulmonary gas exchange, oxygen-carrying capacity in the form of hemoglobin, sufficient delivery of oxygenated hemoglobin to the tissue, and an appropriate tissue oxygen demand. In this Case Study in Physiology, we describe a patient with COVID-19 whose pulmonary gas exchange and oxygen delivery were severely compromised by COVID-19 pneumonia requiring extracorporeal membrane oxygenation (ECMO) support. His clinical course was complicated by a secondary superinfection with staphylococcus aureus and sepsis. This case study is provided with two goals in mind (1) We outline how basic physiology was used to address life-threatening consequences of a novel infection-COVID-19. (2) We describe a strategy of whole-body cooling to lower the cardiac output and oxygen consumption, use of the shunt equation to optimize flow to the ECMO circuit, and transfusion to improve oxygen-carrying capacity when ECMO alone failed to provide sufficient oxygenation.

Supranormal expiratory airflow after bilateral lung transplantation is associated with improved survival.

RATIONALE: flow volume loops (FVL) in some bilateral lung transplant (BLT) and heart-lung transplant (HLT) patients suggest variable extrathoracic obstruction in the absence of identifiable causes. These FVLs usually have supranormal expiratory and normal inspiratory flow rates (SUPRA pattern). OBJECTIVES: characterize the relationship of the SUPRA pattern to predicted donor and recipient lung volumes, airway size, and survival. METHODS: we performed a retrospective review of adult BLT/HLT patients. We defined the SUPRA FVL pattern as: (1) mid-vital capacity expiratory to inspiratory flow ratio (Ve50:Vi50) > 1.0, (2) absence of identifiable causes of extrathoracic obstruction, and (3) Ve50/FVC ≥ 1.5 s(-1). We calculated predicted total lung capacity (pTLC) ratio by dividing the donor pTLC by the recipient pTLC. We measured airway luminal areas on thoracic computer tomographic scans. We compared survival in patients with and without the SUPRA pattern. MEASUREMENTS AND MAIN RESULTS: the SUPRA FVL pattern occurred in 56% of the 89 patients who qualified for the analysis. The pTLC ratio of SUPRA and non-SUPRA patients was 1.11 and 0.99, respectively (P = 0.004). A higher pTLC ratio was correlated with increased probability of the SUPRA pattern (P = 0.0072). Airway luminal areas were larger in SUPRA patients (P = 0.009). Survival was better in the SUPRA cohort (P = 0.009). CONCLUSIONS: the SUPRA FVL pattern was frequent in BLT/HLT patients. High expiratory flows in SUPRA patients could result from increased lung elastic recoil or reduced airway resistance, both of which could be caused by the pTLC mismatch. Improved survival in the SUPRA cohort suggests potential therapeutic approaches to improve outcomes in BLT/HLT patients.

The influence of the primary tumor on the long-term results of pulmonary metastasectomy for metastatic renal cell carcinoma.

OBJECTIVE: To investigate one of the primary tumor (PT) on pulmonary metastasectomy (PM) for metastatic renal cell carcinoma (RCC) and to define prognostic factors. METHODS: Retrospective review of patients with pulmonary metastases from RCC from January 1999 through December 2008 was performed. All patients underwent PM with curative intend. TNM-classification, tumor stage and PT grade, disease-free-interval (DFI) from nephrectomy to the diagnosis of metastasis, systemic chemotherapy before surgical intervention, surgical procedures, morbidity, mortality, and survival were investigated. RESULTS: One-hundred seven consecutive patients (age 61.5 ± 9.6 years) underwent PM. Morbidity and mortality rates were 15.0 and 0.9%, respectively. Thirty-six patients (33.6%) had systematic therapy before PM. Complete resections could be achieved in 104 patients (97.2%). Mean survival was 63.4 ± 5.1 months. The overall 5- and 10-year survival rates were 47 and 9%, respectively. Advanced N-Status (p < 0.001), grade (p < 0.001) and stage group (stage I/II vs. III/IV, p = 0.022) of the PT were associated with inferior survival in the univariate analysis. T-Status (p = 0.89) and M-Status (p = 0.96) of the PT had no significant impact on survival. In a multivariable Cox proportional hazards model, N-Status and tumor grade were the only significant prognostic factors. CONCLUSIONS: PM can be performed safely. Long-term survival is achievable in selected patients. Nodal disease and high tumor grade of the PT at the time of the initial nephrectomy were associated with worse survival after PM. These results might help to identify a high-risk group of patients who might benefit from enrollment in adjuvant therapy protocols after primary treatment of RCC.

The role of residual tumor resection in the management of nonseminomatous germ cell cancer of testicular origin.

OBJECTIVE: To assess the outcome of patients with testicular nonseminomatous germ cell tumors (TNSGCT) undergoing intrathoracic residual tumor resection (RTR) after previous chemotherapy (CT) at a single institution. METHODS: The office records of all patients who underwent intrathoracic RTR for TNSGCT after CT at a single institution from January 2000 through December 2006 were reviewed. RESULTS: There were 124 consecutive patients (age 33.1 ± 8.4 years) with residual masses who underwent 189 surgical procedures. Morbidity and mortality rates were 12.7 and 0.5%, respectively. Complete resections could be achieved in 121 patients (97.6%). In the resected lung masses, necrosis was the predominant histology, (44.4 vs. 29% in mediastinal masses p = 0.018). Mature teratoma was the leading histology in the mediastinum (62.1 vs. 39.5% in lung masses, p = 0.0006). Fifty-nine out of 124 patients (47.6%) required interventions at both lungs and had discordant histological results in 20.3% (12/59) of the cases. Mean survival was 86.6 ± 2.6 months. The overall 5-year-survival and 10-year survival rates were 87 and 85%, respectively. Viable cancer, incomplete resections, age ≥ 34 years, and major pulmonary resections were associated with inferior survival in a univariate Cox proportional hazards model. In a multivariable Cox proportional hazards model, viable cancer, incomplete resections, and major pulmonary resections remained significant prognostic factors. CONCLUSIONS: In selected TNSGCT patients with residual masses, RTR can be performed safely after CT. RTR should be attempted at all sites because of possible discordant histological differentiation. Complete and parenchyma-sparing resections are associated with excellent long-term survival, which can be influenced by the surgeon.

The U-shaped association of post-lung transplant mortality with pretransplant eGFR underscores possible limitations of creatinine-based estimation equations for risk stratification.

BACKGROUND: Pre-existing chronic kidney disease (CKD) may have an impact on post-lung transplant survival and the development of end stage kidney disease (ESKD). METHODS: We analyzed the US transplant database from 2006 to 2020. Adult patients who received their first lung transplant and were not on dialysis were included. Multivariable Cox regression was used to assess the effect of pretransplant eGFR on mortality and cumulative incidence competing risk was used to explore the effect on ESKD. RESULTS: The adjusted hazard ratio (aHR) for mortality showed a "U" shaped association with eGFR with a rising mortality at <60 and >100 ml/min/1.73m2. The increase in mortality with higher eGFR was only seen in those <30 year and were primarily in whites with a lower body mass index and in patients with cystic fibrosis (CF). The aHR for ESKD increased below an eGFR of 100 rising to 1.74 at an eGFR of 60. Any decrease in eGFR between listing and transplant >10% was associated with higher risk of ESKD. CONCLUSIONS: The U-shaped association of pretransplant eGFR with post-transplant mortality correlated with younger age, lower BMI and a diagnosis of CF. The aHR for ESKD following lung transplantation increased exponentially with worsening eGFR pretransplant.

Statin therapy is associated with decreased pulmonary vascular pressures in severe COPD.

BACKGROUND: Pulmonary hypertension (PH) in COPD carries a poor prognosis. Statin therapy has been associated with numerous beneficial clinical effects in COPD, including a possible improvement in PH. We examined the association between statin use and pulmonary hemodynamics in a well-characterized cohort of patients undergoing evaluation for lung transplantation. METHODS: We conducted a cross-sectional analysis of 112 subjects evaluated for lung transplant with a diagnosis of COPD. Clinical characteristics, pulmonary function, cardiac catheterization findings and medical comorbidities were compared between statins users and non-users. RESULTS: Thirty-four (30%) subjects were receiving statin therapy. Statin users were older and had an increased prevalence of systemic hypertension and coronary artery disease (CAD). Mean pulmonary arterial pressure (mPAP) in the statin group was lower [26 ± 7 vs 29 ± 7 mmHg, p = 0.02], as was pulmonary artery wedge pressure (PAWP) [12 ± 5 vs. 15 ± 6 mmHg, p = 0.02]. Pulmonary vascular resistance did not differ between the groups. In multiple regression analysis, statin use was associated with a 4.2 mmHg (95% CI: 2 to 6.4, p = <0.001) lower PAWP and a 2.6 mmHg (95% CI: 0.3 to 4.9, p = 0.03) reduction in mPAP independent of PAWP. CONCLUSIONS: In patients with severe COPD, statin use is associated with significantly lower PAWP and mPAP. These finding should be evaluated prospectively.

Multimodal and palliative treatment of patients with pulmonary metastases.

Pulmonary metastasectomy has become an important part of the multimodality treatment. Surgical practice is based on observational studies published during the last decades, since no randomized clinical trials exist on the topic. However, the overall survival can be improved after pulmonary metastasectomy in carefully selected patients. The objective of resection of pulmonary metastases is to remove all tumor while preserving as much normal pulmonary parenchyma as possible and reduce invasiveness. Contrary, nonsurgical local treatment options for pulmonary metastases include thermal ablation techniques and stereotactic ablative body radiation. Thermal ablation techniques include microwave, cryotherapy and radiofrequency ablation. The present review article gives an overview on the topic and should help thoracic surgeons to make the right decisions in their daily practice.

Preserved Ratio Impaired Spirometry in a Spirometry Database.

BACKGROUND: Spirometry results can yield a diagnosis of normal air flow, air flow obstruction, or preserved ratio impaired spirometry (PRISm), defined as a reduced FEV1 or FVC in the setting of preserved FEV1/FVC. Previous studies have estimated the prevalence of PRISm to be 7-12%. Our objective was to examine the prevalence of PRISm in a spirometry database and to identify factors associated with PRISm. METHODS: We performed a retrospective analysis of 21,870 spirometries; 1,616 were excluded because of missing data or extremes of age, height, or weight. We calculated the prevalence of PRISm in prebronchodilator and postbronchodilator pulmonary function tests. Subsequently, we calculated the prevalence of PRISm by various age, race, body mass index, and diagnosis categories, as well as by gender and smokers versus nonsmokers. Finally, in the subset of the cohort with FEV1 < lower limit of normal, we performed a multivariable logistic regression analysis to identify factors associated with PRISm. RESULTS: We identified 18,059 prebronchodilator spirometries, and 22.3% of these yielded a PRISm diagnosis. This prevalence remained stable in postbronchodilator spirometries (17.7%), after excluding earlier pulmonary function tests for subjects with multiple pulmonary function tests (20.7% in prebronchodilator and 24.3% in postbronchodilator), and when we limited the analysis to prebronchodilator spirometries that met American Thoracic Society criteria (20.6%). The PRISm prevalence was higher in subjects 45-60 y old (24.4%) and in males (23.7%) versus females (17.9%). The prevalence rose with body mass index and was higher for those with a referral diagnosis of restrictive lung disease (50%). PRISm prevalence was similar between races and smokers versus nonsmokers. In a multivariable analysis, higher % of predicted FEV1 (odds ratio 1.51, 95% CI 1.42-1.60), body mass index (odds ratio 1.52, 95% CI 1.39-1.68), and restrictive lung disease (odds ratio 4.32, 95% CI 2.54-7.57) were associated with a diagnosis of PRISm. Smoking was inversely associated (odds ratio 0.55, 95% CI 0.46-0.65) with PRISm. CONCLUSIONS: In a spirometry database at an academic medical center, the PRISm prevalence was 17-24%, which is higher than previously reported.