Tissue resident iNKT17 cells facilitate cancer cell extravasation in liver metastasis via interleukin-22.

During metastasis, cancer cells invade, intravasate, enter the circulation, extravasate, and colonize target organs. Here, we examined the role of interleukin (IL)-22 in metastasis. Immune cell-derived IL-22 acts on epithelial tissues, promoting regeneration and healing upon tissue damage, but it is also associated with malignancy. Il22-deficient mice and mice treated with an IL-22 antibody were protected from colon-cancer-derived liver and lung metastasis formation, while overexpression of IL-22 promoted metastasis. Mechanistically, IL-22 acted on endothelial cells, promoting endothelial permeability and cancer cell transmigration via induction of endothelial aminopeptidase N. Multi-parameter flow cytometry and single-cell sequencing of immune cells isolated during cancer cell extravasation into the liver revealed iNKT17 cells as source of IL-22. iNKT-cell-deficient mice exhibited reduced metastases, which was reversed by injection of wild type, but not Il22-deficient, invariant natural killer T (iNKT) cells. IL-22-producing iNKT cells promoting metastasis were tissue resident, as demonstrated by parabiosis. Thus, IL-22 may present a therapeutic target for prevention of metastasis.

Murine orthotopic lung transplant models: A comprehensive overview of genetic mismatch degrees and histopathological insights into chronic lung allograft dysfunction.

Currently, lung transplantation outcome remains inferior compared to other solid organ transplantations. A major cause for limited survival after lung transplantation is chronic lung allograft dysfunction. Numerous animal models have been developed to investigate chronic lung allograft dysfunction to discover adequate treatments. The murine orthotopic lung transplant model has been further optimized over the last years. However, different degrees of genetic mismatch between donor and recipient mice have been used, applying a single, minor, moderate, and major genetic mismatch. This review aims to reassess the existing murine mismatch models and provide a comprehensive overview, with a specific focus on their eventual histopathological presentation. This will be crucial to leverage this model and tailor it according to specific research needs.

Donor age over 55 is associated with worse outcome in lung transplant recipients with idiopathic pulmonary fibrosis.

BACKGROUND: Lung transplantation (LTx) remains the only efficient treatment for selected patients with end-stage pulmonary disease. The age limit for the acceptance of donor organs in LTx is still a matter of debate. We here analyze the impact of donor organ age and the underlying pulmonary disease on short- and long-term outcome and survival after LTx. METHODS: Donor and recipient characteristics of LTx recipients at our institution between 03/2003 and 12/2021 were analyzed. Statistical analysis was performed using SPSS and GraphPad software. RESULTS: In 230 patients analyzed, donor age ≥ 55 years was associated with a higher incidence of severe primary graft dysfunction (PGD2/3) (46% vs. 31%, p = 0.03) and reduced long-term survival after LTx (1-, 5- and 10-year survival: 75%, 54%, 37% vs. 84%, 76%, 69%, p = 0.006). Notably, this was only significant in recipients with idiopathic pulmonary fibrosis (IPF) (PGD: 65%, vs. 37%, p = 0.016; 1-, 5-, and 10-year survival: 62%, 38%, 16% vs. 80%, 76%, 70%, p = 0.0002 respectively). In patients with chronic obstructive pulmonary disease (COPD), donor age had no impact on the incidence of PGD2/3 or survival (21% vs. 27%, p = 0.60 and 68% vs. 72%; p = 0.90 respectively). Moreover, we found higher Torque-teno virus (TTV)-DNA levels after LTx in patients with IPF compared to COPD (X2 = 4.57, p = 0.033). Donor age ≥ 55 is an independent risk factor for reduced survival in the whole cohort and patients with IPF specifically. CONCLUSIONS: In recipients with IPF, donor organ age ≥ 55 years was associated with a higher incidence of PGD2/3 and reduced survival after LTx. The underlying pulmonary disease may thus be a relevant factor for postoperative graft function and survival. TRIAL REGISTRATION NUMBER DKRS: DRKS00033312.

Independent risk factors for an increased incidence of thromboembolism after lung transplantation.

BACKGROUND: Thromboembolism (TE) after lung transplantation (LTX) is associated with increased morbidity and mortality. The aim of this study is to analyze the incidence and outcome of venous and arterial thromboembolic complications and to identify independent risk factors. PATIENTS AND METHODS: We retrospectively analyzed the medical records of 221 patients who underwent LTX at our institution between 2002 and 2021. Statistical analysis was performed using SPSS and GraphPad software. RESULTS: 74 LTX recipients (33%) developed TE. The 30-days incidence and 12-months incidence were 12% and 23%, respectively. Nearly half of the patients (48%) developed pulmonary embolism, 10% ischemic stroke. Arterial hypertension (p = 0.006), a body mass index (BMI) > 30 (p = 0.006) and diabetes mellitus (p = 0.041) were independent predictors for TE. Moreover, a BMI of > 25 at the time of transplantation was associated with an increased risk for TE (43% vs. 32%, p = 0.035). At the time of LTX, 65% of the patients were older than 55 years. An age > 55 years also correlated with the incidence of TE (p = 0.037) and these patients had reduced overall post-transplant survival when the event occurred within the first postoperative year (59% vs. 72%, p = 0.028). CONCLUSIONS: The incidence of TE after LTX is high, especially in lung transplant recipients with a BMI > 25 and an age > 55 years as well as cardiovascular risk factors closely associated with the metabolic syndrome. As these patients comprise a growing recipient fraction, intensified research should focus on the risks and benefits of regular screening or a prolonged TE prophylaxis in these patients. Trial registration number DKRS: 00021501.

Endoscopic Lung Volume Reduction Prior to Lung Transplantation Does Not Increase Postoperative Pulmonary Complications.

INTRODUCTION: Lung transplantation (LTx) remains the only therapeutic option for selected patients with end-stage lung disease. In comparison to surgical lung volume reduction, few data exist on the risks and benefits of pretransplant endoscopic lung volume reduction (eLVR). Here, we investigate the risk of postoperative pulmonary complications (PPCs) after LTx in patients with emphysematous lung disease bridged with eLVR until transplantation. METHODS: Eighty-two patients with emphysematous lung disease who underwent double-LTx (DLTx) were included and retrospectively evaluated. Statistical analysis was performed using SPSS and GraphPad Prism software. RESULTS: 28/82 patients underwent eLVR prior to DLTx. eLVR patients spent comparable time on the waitlist; however, they were older at the time of DLTx (median 60 vs. 58 years, p = 0.02). Both groups showed comparable 90-day (92%) and long-term survival (eLVR 1-/5-/10-year survival: 92/88/77%, vs. control: 89/77/67%, p = 0.5). The odds for PPCs were similar in patients with and without eLVR (OR 0.7; 95% CI: 0.3-1.7), as well as major perioperative surgical and cardiovascular complications. In the entire cohort, we found ≥1 PPC to be a risk factor for death within 90 days (OR 9.7, 95% CI: 1.3-110). Among the PPCs, pneumonia (HR 4.6 95% CI: 1.1-14.9, p = 0.02) and ARDS (HR 11.2 95% CI: 1.6-229.2, p = 0.04) were identified as independent risk factors for reduced long-term survival. CONCLUSIONS: eLVR does not increase the risk for PPCs, surgical complications, or reduced survival after LTx in patients with emphysematous lung disease and can serve as a bridge to LTx.

[Congenital Malformations of the Lung - an Overview]. / Angeborene Fehlbildungen der Lunge ­ eine Übersicht.

Congenital pulmonary malformations comprise a heterogenous group of rare developmental diseases. The most common malformations are the tracheal bronchus, bronchial atresia, bronchogenic cyst, pulmonary sequestration, congenital lobar emphysema, and congenital pulmonary airway malformation. Due to their space-consuming effect, patients suffer early postnatal respiratory distress which generally requires immediate surgical resection. The management of asymptomatic lesions remains subject to debate, but early elective surgery is generally recommended to avoid respiratory and infectious complications at a later time point.We here provide a comprehensive review in which we present causes, clinical presentation and therapeutic options for the most prominent congenital malformations of the airways and lung parenchyma.

Psychometric properties of the updated EORTC module for assessing quality of life in patients with lung cancer (QLQ-LC29): an international, observational field study.

BACKGROUND: The European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire-Lung Cancer 13 (QLQ-LC13) assesses quality of life (QOL) in patients with lung cancer and was the first EORTC module developed for use in international clinical trials. Since its publication in 1994, major treatment advances with possible effects on QOL have occurred. These changes called for an update of the module and its international psychometric validation. We aimed to investigate the scale structure and psychometric properties of the updated lung cancer module, QLQ-LC29, in patients with lung cancer. METHODS: This international, observational field study was done in 19 hospitals across 12 countries. Patients aged older than 18 years with a confirmed diagnosis of lung cancer and no other previous primary tumour, and who were mentally fit with sufficient language skills to understand and complete the questionnaire were included. Patients were asked during a hospital visit to fill in the paper versions of the core questionnaire EORTC QLQ-C30 plus QLQ-LC29, and investigators selected half of these patients to complete the questionnaire again 2-4 weeks later. Our primary aim was to assess the scale structure and psychometric properties of EORTC QLQ-LC29. We analysed scale structure using confirmatory factor analysis; reliability using Cronbach's α value (internal consistency) and intra-class coefficient (test-retest reliability); sensitivity using independent t tests stratified by Karnofsky performance status; and responsiveness to change over time by ANOVA. This study is registered with ClinicalTrials.gov, NCT02745691. FINDINGS: Between April 12, 2016, and Sept 26, 2018, 523 patients with a confirmed diagnosis of either non-small-cell lung cancer (n=442) or small-cell lung cancer (n=81) were recruited. Confirmatory factor analysis provided a solution composed of five multi-item scales (coughing, shortness of breath, fear of progression, hair problems, and surgery-related symptoms) plus 15 single symptom or side-effect items: χ2=370·233, root mean square error of approximation=0·075, and comparative-fit index=0·901. Cronbach's α for internal consistencies of all multi-item scales were above the threshold of 0·70. Intra-class coefficients for test-retest reliabilities ranged between 0·82 and 0·97. Three (shortness of breath, fear of progression, and hair problems) of the five multi-item scales showed responsiveness to change over time (p values <0·05), as did nine of 15 single symptom items. Four (coughing, shortness of breath, fear of progression, and surgery-related symptoms) of the five multi-item scales and ten of the 15 single symptom items were sensitive to known group differences (ie, lower vs higher Karnofsky performance status). INTERPRETATION: Results determined the psychometric properties of the updated lung cancer module, which is ready for use in international clinical studies. FUNDING: EORTC Quality of Life Group.

Lung macrophage scavenger receptor SR-A6 (MARCO) is an adenovirus type-specific virus entry receptor.

Macrophages are a diverse group of phagocytic cells acting in host protection against stress, injury, and pathogens. Here, we show that the scavenger receptor SR-A6 is an entry receptor for human adenoviruses in murine alveolar macrophage-like MPI cells, and important for production of type I interferon. Scavenger receptors contribute to the clearance of endogenous proteins, lipoproteins and pathogens. Knockout of SR-A6 in MPI cells, anti-SR-A6 antibody or the soluble extracellular SR-A6 domain reduced adenovirus type-C5 (HAdV-C5) binding and transduction. Expression of murine SR-A6, and to a lower extent human SR-A6 boosted virion binding to human cells and transduction. Virion clustering by soluble SR-A6 and proximity localization with SR-A6 on MPI cells suggested direct adenovirus interaction with SR-A6. Deletion of the negatively charged hypervariable region 1 (HVR1) of hexon reduced HAdV-C5 binding and transduction, implying that the viral ligand for SR-A6 is hexon. SR-A6 facilitated macrophage entry of HAdV-B35 and HAdV-D26, two important vectors for transduction of hematopoietic cells and human vaccination. The study highlights the importance of scavenger receptors in innate immunity against human viruses.

Can texture analysis in ultrashort echo-time MRI distinguish primary graft dysfunction from acute rejection in lung transplants? A multidimensional assessment in a mouse model.

BACKGROUND: Differentiation of early postoperative complications affects treatment options after lung transplantation. PURPOSE: To assess if texture analysis in ultrashort echo-time (UTE) MRI allows distinction of primary graft dysfunction (PGD) from acute transplant rejection (ATR) in a mouse lung transplant model. STUDY TYPE: Longitudinal. ANIMAL MODEL: Single left lung transplantation was performed in two cohorts of six mice (strain C57BL/6) receiving six syngeneic (strain C57BL/6) and six allogeneic lung transplants (strain BALB/c (H-2Kd )). FIELD STRENGTH/SEQUENCE: 4.7T small-animal MRI/eight different UTE sequences (echo times: 50-5000 µs) at three different postoperative timepoints (1, 3, and 7 days after transplantation). ASSESSMENT: Nineteen different first- and higher-order texture features were computed on multiple axial slices for each combination of UTE and timepoint (24 setups) in each mouse. Texture features were compared for transplanted (graft) and contralateral native lungs between and within syngeneic and allogeneic cohorts. Histopathology served as a reference. STATISTICAL TESTS: Nonparametric tests and correlation matrix analysis were used. RESULTS: Pathology revealed PGD in the syngeneic and ATR in the allogeneic cohort. Skewness and low-gray-level run-length features were significantly different between PGD and ATR for all investigated setups (P < 0.03). These features were significantly different between graft and native lung in ATR for most setups (minimum of 20/24 setups; all P < 0.05). The number of significantly different features between PGD and ATR increased with elapsing postoperative time. Differences in significant features were highest for an echo-time of 1500 µs. DATA CONCLUSION: Our findings suggest that texture analysis in UTE-MRI might be a tool for the differentiation of PGD and ATR in the early postoperative phase after lung transplantation. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2020;51:108-116.

The CD26/DPP4-inhibitor vildagliptin suppresses lung cancer growth via macrophage-mediated NK cell activity.

CD26/dipeptidyl peptidase 4 (DPP4) is a transmembrane protein which is expressed by various malignant cells. We found that the expression of CD26/DPP4 was significantly higher in lung adenocarcinoma samples in our own patient cohort compared to normal lung tissue. We therefore hypothesize that the inhibition of CD26/DPP4 can potentially suppress lung cancer growth. The CD26/DPP4 inhibitor vildagliptin was employed on Lewis Lung Carcinoma (LLC) cell line and a human lung adenocarcinoma (H460) cell line. Two weeks after subcutaneous injection of tumor cells into C57BL/6 and CD1/nude mice, the size of LLC and H460 tumors was significantly reduced by vildagliptin. Immunohistochemically, the number of macrophages (F4/80+) and NK cells (NKp46+) was significantly increased in vildagliptin-treated tumor samples. Mechanistically, we found in vitro that lung cancer cell lines expressed increased levels of surfactant protein upon vildagliptin treatment thereby promoting the pro-inflammatory activity of macrophages. By the depletion of macrophages with clodronate and by using NK cell deficient (IL-15-/-) mice, tumors reversed to the size of controls, suggesting that indeed macrophages and NK cells were responsible for the observed tumor-suppressing effect upon vildagliptin treatment. FACS analysis showed tumor-infiltrating NK cells to express tumor necrosis-related apoptosis-inducing ligand (TRAIL) which induced the intra-cellular stress marker γH2AX. Accordingly, we found upregulated γH2AX in vildagliptin-treated tumors and TRAIL-treated cell lines. Moreover, the effect of vildagliptin-mediated enhanced NK cell cytotoxicity could be reversed by antagonizing the TRAIL receptor. Our data provide evidence that the CD26/DPP4-inhibitor vildagliptin reduces lung cancer growth. We could demonstrate that this effect is exerted by surfactant-activated macrophages and NK cells that act against the tumor via TRAIL-mediated cytotoxicity.

T Helper Cell Subsets in Experimental Lung Allograft Rejection.

BACKGROUND: Human lung transplantation has evolved to an established treatment for pulmonary diseases in their end stages; however, the long-term outcome is worse when compared to all other solid transplantable organs. The major reason for this unfavorable outcome is rejection, either in its acute or chronic form, the latter termed as chronic lung allograft dysfunction. METHODS: A systematic review search was performed. RESULTS: One of the most important immune cells responsible for rejection are T cells. Beside alloreactive CD8+ T cells, CD4+ T cells play a key role during the evolvement of allograft rejection. Certain subsets of these allograft CD4+ T cells have been identified which have been shown to exert either transplant-protective or transplant-injuring properties. These effects have been proven in various experimental models, mainly in rats and mice, and allowed for the gain of important insights into these proinflammatory and anti-inflammatory characteristics including their targetability: while the subsets Th1, Th17, Th22, and Tfh cells have been shown to act in a rather proinflammatory way, Tregs, Th2, and Th9 subsets exert anti-inflammatory effects. Chronic airway obstruction is mainly induced by IL17 as shown across models. CONCLUSIONS: This review shall summarize and provide an overview of the current evidence about the role and effects of proinflammatory and anti-inflammatory CD4-+ T helper cell subsets during lung allograft rejection in experimental rodent models.

The Amide Local Anesthetic Ropivacaine Attenuates Acute Rejection After Allogeneic Mouse Lung Transplantation.

PURPOSE: Acute allograft rejection after lung transplantation remains an unsolved hurdle. The pathogenesis includes an inflammatory response during and after transplantation. Ropivacaine, an amide-linked local anesthetic, has been shown to attenuate lung injury due to its anti-inflammatory effects. We hypothesized that the drug would also be able to attenuate acute rejection (AR) after allogeneic lung transplantation. METHODS: Allogeneic, orthotopic, single left lung transplantation was performed between BALB/c (donors) and C57BL/6 (recipients) mice. Prior to explantation, lungs were flushed with normal saline with or without ropivacaine (final concentration 1 µM). Plasma levels of tumor necrosis factor-α and interleukins - 6 and - 10 were measured 3 h after transplantation by ELISA. Lung function was assessed on postoperative day five and transplanted lungs were analyzed using histology (AR), immunohistochemistry (infiltrating leukocytes) and Western blot (phosphorylation and expression of Src and caveolin-1). RESULTS: Ropivacaine pre-treatment significantly reduced AR scores (median 3 [minimum-maximum 2-4] for control vs. 2 [1-2] for ropivacaine, p < 0.001) and plasma levels of tumor necrosis factor-α (p = 0.01) compared to control, whereas plasma concentrations of interleukin - 6 (p = 0.008) and - 10 (p < 0.001) were increased by ropivacaine. The number of T-lymphocytes infiltrating the transplanted lung was attenuated (p = 0.02), while no differences in macrophage or B-lymphocyte numbers could be observed after ropivacaine pre-treatment. Caveolin-1 phosphorylation in ropivacaine-treated lungs was diminished (p = 0.004). CONCLUSIONS: Pre-treatment of donor lungs with the local anesthetic ropivacaine diminished histological signs of AR after orthotopic left lung transplantation in mice, most likely due to reduced infiltration of T-lymphocytes into the graft.

Sevoflurane preconditioning protects from posttransplant injury in mouse lung transplantation.

BACKGROUND: Although sevoflurane (Sevo) had been shown to ameliorate posttransplant injury in various organs, data available are inconsistent, particularly in the context of lung transplantation (Tx). We here investigated if preconditioning by Sevo can protect from posttransplant injury regarding both, primary graft dysfunction (PGD) and acute rejection (AR) after experimental lung Tx, thereby focusing on two important clinical outcome parameters. MATERIALS AND METHODS: Three experimental approaches were used: (1) BALB/c mice were preconditioned for 2 h with Sevo or a fentanyl cocktail (Control; n = 10); (2) syngeneic (Syn) mouse lung Tx (C57BL/6) with a Sevo-preconditioned graft followed by 18 h storage to mimic PGD (Syn-Tx, n = 12) versus controls (fentanyl cocktail); and (3) allogeneic (Allo) Tx (BALB/c, donor; C57BL/6, recipient) to mimic AR (Allo-Tx, n = 12) versus controls (fentanyl cocktail). Syn-Tx grafts were harvested on Day 1, Allo-Tx grafts on Day 3 and analyzed for histology, immunohistochemistry, blood gas analysis, and inflammatory cytokines (enzyme-linked immunosorbent assay or reverse transcription polymerase chain reaction). RESULTS: Evaluating the preconditioning effect of Sevo only showed significantly better oxygenation (P = 0.03) and a tendency toward lower levels of lung tissue messenger RNA for tumor necrosis factor-α. In Syn-Tx recipients, the Sevo group had histologically a tendency toward an attenuation of PGD and showed significantly lower levels of interleukin 6 (P = 0.01) in plasma, but higher levels of interleukin 10 (P < 0.01) in lungs. Allo-Tx grafts in Sevo Tx recipients showed attenuated AR with histologically significantly lower rejection scores (P = 0.03), fewer classical macrophages (F4/80+; P < 0.01), but more anti-inflammatory activated macrophages (M2, CD206+; P < 0.01). Functionally, the Sevo group had a tendency toward improved oxygenation. CONCLUSIONS: We demonstrated that Sevo preconditioning has protective effects on lung transplants in both, PGD and AR. The observed amelioration may be attributed to suppressed inflammatory cytokines during PGD and the induction of alternatively activated macrophages during AR. These promising data could set the base for using Sevo preconditioning in donor lungs for a human trial.

Ex vivo treatment with inhaled N-acetylcysteine in porcine lung transplantation.

BACKGROUND: We have shown the beneficial effects of N-acetylcysteine (NAC) on posttransplant lung function, when both donor and recipient were pretreated intravenously. However, systemic treatment of multiorgan donors may not be clinically relevant. Thus, we hypothesized that ex vivo treatment of donors with nebulized NAC would be adequate to prevent from ischemia-reperfusion injury after lung transplantation. METHODS: Lungs were retrieved from domestic pigs and stored at 4°C for 24 h followed by 2 h of ex vivo lung perfusion (EVLP) to administer 50 mg/kg of NAC via nebulization in the NAC group (n = 6). The control group received nebulized saline (n = 5). Left lungs were transplanted and isolated at 1 h of reperfusion by occluding the right main bronchus and pulmonary artery, followed by 5 h of observation. Physiological data during EVLP and after reperfusion were recorded. Inflammatory response, markers of oxidative stress, and microscopic lung injury were analyzed. RESULTS: There was a trend toward better oxygenation throughout reperfusion period in the treatment group, which was accompanied by inhibited inflammatory response related to reduction in myeloperoxidase activity during EVLP and nuclear factor-κB activation at the end of reperfusion. CONCLUSIONS: Ex vivo treatment of donor lungs with inhaled NAC reduced inflammatory response via its antioxidant activity in experimental porcine lung transplantation.

Sarcoidosis as a rare cause for symmetrical giant bullous disease.

BACKGROUND: Sarcoidosis presents with typical clinic-radiological findings and shows histologically non-caseating granulomas. Pulmonary manifestations of sarcoidosis can be diverse, involving the intrathoracic lymph nodes and pulmonary parenchyma. CASE PRESENTATION: We here describe a case of a 35-year-old patient who presented with a history of exertion dyspnoea and coughing for the past 20 years. At the age of 15, she was exposed to smoke emanating from a fire. Later, she had exposure to mold for two years, and during her childhood, she had animals such as a cockatiel, dog, cat, gecko, and turtle. Computed tomography of the chest revealed symmetrical apical giant bullous lesions. Histology of the resected bullae showed prominent peribronchial fibrosis with non-necrotizing, non-caseating granulomas and collaps of pulmonary lobules adjacent to the bulla. The absence of granulomatous infection and a markedly elevated CD4:CD8 ratio in bronchoalveolar lavage analysis suggested that the underlying process was sarcoidosis. CONCLUSION: In very rare cases, sarcoidosis can be associated with bilateral symmetrical apical giant bullous disease due to fibrotic and granulomatous changes resulting in a restriction of lung tissue.

[Current Indications for Surgery in Small Cell Lung Cancer]. / Aktuelle Indikationen zur operativen Therapie beim kleinzelligen Lungenkarzinom.

Small cell lung cancer (SCLC) is characterised by an aggressive and rapid growth, with a tendency towards early metastatic spread. It has one of the worst prognoses of all malignancies. Though radio-chemotherapy is still considered the mainstay of therapy due to its high sensitivity, increasing evidence, supported by a number of retrospective analyses and large case series, suggests that surgery may play a significant role in the treatment of SCLC within a multimodality treatment concept. In this context, surgery can provide overall survival benefit and improve local control in selected cases. Currently, an operation can be recommended if the SCLC manifests as a single peripheral node, in early cancer stages (T1 - 2, N0, M0), in cases of mixed histological tumour types but also in selected cases in chemotherapy-resistant tumors. In the light of the current availability of immunotherapy by checkpoint inhibitors, resection of SCLC should also be considered on the basis of the expression of checkpoint receptors that might have relevant impact on therapy and prognosis of the course of SCLC. In order to fulfil the above-mentioned criteria and to provide a higher level of evidence and to develop guidelines, randomised controlled trials need to be performed.

In vivo magnetization transfer imaging of the lung using a zero echo time sequence at 4.7 Tesla in mice: Initial experience.

PURPOSE: The aim of the present study was to assess the feasibility of magnetization transfer-prepared zero echo time (ZTE) imaging of the lung in vivo at high field strength [4.7 Tesla) T] in mice. METHODS: Eighteen C57BL/10 mice underwent MRI examinations in a 4.7T MR-scanner. A three-dimensional ZTE sequence was applied for lung imaging combined with a Gaussian MT-prepulse, which was followed by a train of 100 ZTE imaging readouts. Degree of MT was assessed by calculation of the magnetization transfer ratio (MTR). Direct saturation was estimated using Bloch equation simulations based on T1 measurements. The line-width of pulmonary tissue was estimated using T2* measurements. RESULTS: Experimental MTR-values of nonpulmonary tissues obtained with ZTE exhibited the characteristics known from conventional MT-sequences (skeletal muscle and liver: high values; fatty tissue: low values). Lung tissue demonstrated MTR-values in between fatty tissue and liver tissue. Direct saturation could be estimated by the Bloch simulation; however, an adequate approximation was only possible for T2 values nearly in the range of parenchymal organs. CONCLUSION: Pulmonary MT measurements at high field strength using the proposed MT-ZTE sequence is feasible; however, estimation of direct saturation remains challenging. Magn Reson Med 76:156-162, 2016. © 2015 Wiley Periodicals, Inc.

Magnetization transfer as a potential tool for the early detection of acute graft rejection after lung transplantation in mice.

PURPOSE: To investigate the value of magnetization transfer (MT) measurements for assessment of acute rejection (AR) in a murine lung transplantation model. MATERIALS AND METHODS: Thirty mice including 15 C57BL/10 mice serving as donors and 15 C57BL/6 mice as recipients were examined in this study. MT imaging datasets were acquired on a 4.7 Tesla small animal MR scanner using a three-dimensional zero echo time sequence with a Gaussian-shaped MT prepulse with 1000° or 3000° flip angle and systematic variation of off-resonance frequencies between 1000 and 15,000 Hz. After image acquisition, the images were qualitatively assessed, magnetization transfer ratio (MTR) values were calculated and lungs were taken for histologic examination including staining with hematoxylin/eosin, Masson's trichrome (collagen), and α-smooth muscle (fibroproliferative tissue) staining. RESULTS: Lung transplantation was successfully performed in all 15 mice. All animals showed AR characterized by the presence of interstitial mononuclear cell infiltrates. There were significant differences of MTR in lungs with and without AR (P = 0.007). With a flip angle of 1000°, the largest differences between the MTR of healthy lungs and lungs with AR were observed for an off-resonance frequency of 10,000 Hz (difference MTR 1.80%) and 15,000 Hz (1.91%) and with a flip angle of 3000° at off-resonance frequencies of 6000 Hz (1.37%) and 8000 Hz (1.70%). CONCLUSION: MT measurements may provide a tool for the quantitative assessment of AR. J. Magn. Reson. Imaging 2016;44:1091-1098.

Ultra-short echo-time magnetic resonance imaging distinguishes ischemia/reperfusion injury from acute rejection in a mouse lung transplantation model.

To investigate whether lung tissue characterization by ultra-short echo-time (UTE) magnetic resonance imaging (MRI) allows ischemia/reperfusion injury to be distinguished from acute rejection in a mouse lung transplantation model. After orthotopic lung transplantation with 6 mice receiving syngeneic (C57Bl/6) lung transplants and 6 mice receiving allogeneic (BALB/c) transplants, they underwent postoperative imaging using three-dimensional UTE-MRI (echo times TE = 50-5000 µs) and conventional T2-weighted fast spin-echo imaging. Quantitative T2* values of lung transplant parenchyma and spin density (SD) were compared by region-of-interest analysis. All samples underwent histological and immunohistochemical workup. In the allogeneic group, alveolar infiltration resulting from acute organ rejection was visualized in the UTE sequences. This was reflected by the quantitative measurements of SD and T2* values with higher values in the allogeneic group compared with the syngeneic group and nontransplanted lung at the first time point (24 h postoperative: Tx allogeneic group SD: 2133.9 ± 516; Tx syngeneic group SD: 1648.61 ± 271; P = 0.004; Tx allogeneic group T2*: 1710.16 ± 644 µs, Tx syngeneic group T2*: 577.16 ± 263 µs; P = <0.001). Changes caused by acute rejection after lung transplantation can be visualized and characterized using a UTE sequence due to different relaxation properties compared with both syngeneic lung transplants and normal lung tissue.

A murine model of lung ischemia and reperfusion injury: tricks of the trade.

BACKGROUND: Pulmonary ischemia-reperfusion injury (IRI) causes postoperative morbidity in patients undergoing lung transplantation, isolated lung perfusion, and cardiopulmonary bypass and may lead to potentially lethal pathologies such as respiratory shock. In-depth study of this pathology requires a reliable animal model. Mice are a popular species to develop experimental models because of their logistic advantages and the availability of knock outs. However, their small size warrants microsurgical techniques and a skilled surgeon. MATERIALS AND METHODS: We developed a murine model of pulmonary anoxic IRI through hilar clamping using adult female Swiss mice. After left thoracotomy, we expose the pulmonary hilum keeping the ribs and the muscles of back and forepaw intact. A microvascular clamp is placed over the entire hilum, occluding bronchus, pulmonary artery, and vein. RESULTS: Our model proved to be simple, reliable, and reproducible, showing minimal preoperative and postoperative mortality. Histopathologic analysis indicated all characteristic features of pulmonary IRI, such as an early recruitment of lymphocytes followed by neutrophil influx. CONCLUSIONS: This article presents a murine surgery model for pulmonary IRI based on a muscle-sparing thoracotomy. The minimal approach limits manipulation of lung tissue, minimizing mortality and non-IRI-induced injury.