Sfrp1 inhibits lung fibroblast invasion during transition to injury-induced myofibroblasts.

BACKGROUND: Fibroblast-to-myofibroblast conversion is a major driver of tissue remodelling in organ fibrosis. Distinct lineages of fibroblasts support homeostatic tissue niche functions, yet their specific activation states and phenotypic trajectories during injury and repair have remained unclear. METHODS: We combined spatial transcriptomics, multiplexed immunostainings, longitudinal single-cell RNA-sequencing and genetic lineage tracing to study fibroblast fates during mouse lung regeneration. Our findings were validated in idiopathic pulmonary fibrosis patient tissues in situ as well as in cell differentiation and invasion assays using patient lung fibroblasts. Cell differentiation and invasion assays established a function of SFRP1 in regulating human lung fibroblast invasion in response to transforming growth factor (TGF)ß1. MEASUREMENTS AND MAIN RESULTS: We discovered a transitional fibroblast state characterised by high Sfrp1 expression, derived from both Tcf21-Cre lineage positive and negative cells. Sfrp1 + cells appeared early after injury in peribronchiolar, adventitial and alveolar locations and preceded the emergence of myofibroblasts. We identified lineage-specific paracrine signals and inferred converging transcriptional trajectories towards Sfrp1 + transitional fibroblasts and Cthrc1 + myofibroblasts. TGFß1 downregulated SFRP1 in noninvasive transitional cells and induced their switch to an invasive CTHRC1+ myofibroblast identity. Finally, using loss-of-function studies we showed that SFRP1 modulates TGFß1-induced fibroblast invasion and RHOA pathway activity. CONCLUSIONS: Our study reveals the convergence of spatially and transcriptionally distinct fibroblast lineages into transcriptionally uniform myofibroblasts and identifies SFRP1 as a modulator of TGFß1-driven fibroblast phenotypes in fibrogenesis. These findings are relevant in the context of therapeutic interventions that aim at limiting or reversing fibroblast foci formation.

Targeting genomic SARS-CoV-2 RNA with siRNAs allows efficient inhibition of viral replication and spread.

A promising approach to tackle the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) could be small interfering (si)RNAs. So far it is unclear, which viral replication steps can be efficiently inhibited with siRNAs. Here, we report that siRNAs can target genomic RNA (gRNA) of SARS-CoV-2 after cell entry, and thereby terminate replication before start of transcription and prevent virus-induced cell death. Coronaviruses replicate via negative sense RNA intermediates using a unique discontinuous transcription process. As a result, each viral RNA contains identical sequences at the 5' and 3' end. Surprisingly, siRNAs were not active against intermediate negative sense transcripts. Targeting common sequences shared by all viral transcripts allowed simultaneous suppression of gRNA and subgenomic (sg)RNAs by a single siRNA. The most effective suppression of viral replication and spread, however, was achieved by siRNAs that targeted open reading frame 1 (ORF1) which only exists in gRNA. In contrast, siRNAs that targeted the common regions of transcripts were outcompeted by the highly abundant sgRNAs leading to an impaired antiviral efficacy. Verifying the translational relevance of these findings, we show that a chemically modified siRNA that targets a highly conserved region of ORF1, inhibited SARS-CoV-2 replication ex vivo in explants of the human lung. Our work encourages the development of siRNA-based therapies for COVID-19 and suggests that early therapy start, or prophylactic application, together with specifically targeting gRNA, might be key for high antiviral efficacy.

Long-term multicenter comparison shows equivalent efficacy of monoclonal antibodies in severe asthma therapy.

BACKGROUND: Monoclonal antibodies (biologics) drastically changed severe asthma therapy. Mepolizumab (anti-interleukin (IL) 5), benralizumab (anti-IL5 receptor alpha), and dupilumab (anti-IL4/13) are the most used biologics in this context. While all biologics are efficient individually, the choice of biologic is complicated by insufficient data on their comparative long-term treatment efficacy. Here, we compare the real-life efficacy of these biologics in asthma therapy over 12 months. METHODS: 280 severe asthma patients treated with mepolizumab (129/280, 46%), benralizumab (83/280, 30%) or dupilumab (68/280, 24%) for one year were analyzed retrospectively. Data were collected at baseline and after 6 and 12 months of therapy. Endpoints were changes pulmonary function (PF), exacerbation rate, oral corticosteroid (OCS) use and dose, asthma control test (ACT) score and fractional exhaled nitric oxide (FeNO) levels as well as responder status measured by the recently published "Biologic Asthma Response Score" (BARS). RESULTS: All biologics led to significant improvements in PF, ACT and OCS dose. Only Mepolizumab and Benralizumab significantly decreased the exacerbation rate, while only Mepolizumab and Dupilumab significantly decreased FeNO. Responder rates measured by BARS were high across all groups: roughly half of all patients achieved full response and most of the remainder achieved at least partial responder status. Overall, outcomes were similar between groups after both 6 and 12 months. CONCLUSIONS: All biologics showed great efficacy in individual parameters and high responder rates measured by BARS without a clinically relevant advantage for any antibody. Response was usually achieved after 6 months and retained at 12 months, emphasizing the utility of early response assessment.

[Therapeutic Pathways in Sarcoidosis. A Position Paper of the German Society of Respiratory Medicine (DGP)]. / Therapie der Sarkoidose. Ein Positionspapier der Deutschen Gesellschaft für Pneumologie und Beatmungsmedizin (DGP).

The present recommendations on the therapy of sarcoidosis of the German Respiratory Society (DGP) was written in 2023 as a German-language supplement and update of the international guidelines of the European Respiratory Society (ERS) from 2021. It contains 5 PICO questions (Patients, Intervention, Comparison, Outcomes) agreed in the consensus process, which are explained in the background text of the four articles: Confirmation of diagnosis and monitoring of the disease under therapy, general therapy recommendations, therapy of cutaneous sarcoidosis, therapy of cardiac sarcoidosis.

Posterior reversible encephalopathy syndrome after lung transplantation: Risk factors and management.

INTRODUCTION: Posterior reversible encephalopathy syndrome is a rare neurologic complication that can occur under immunosuppressive therapy with CNI after organ transplantation. METHODS: We retrospectively reviewed medical records of 545 patients who underwent lung transplantation between 2012 and 2019. Within this group, we identified 30 patients with neurological symptoms typical of PRES and compared the characteristics of patients who were diagnosed with PRES (n = 11) to those who were not (n = 19). RESULTS: The incidence of PRES after lung transplantation was 2%. Notably, 73% of the patients with PRES were female and the mean age was 39.2. Seizure (82% vs. 21%, p = .002) was the most common neurological presentation. The risk of developing PRES was significantly associated with age (OR = .92, p < .0001) and having cystic fibrosis (CF) (OP = 10.1, p < .0001). Creatinine level (1.9 vs. 1.1 mg/dl, p = .047) and tacrolimus trough level (19.4 vs. 16.5 ng/ml, p = .048) within 1 week prior to neurological symptoms were significantly higher in patients with PRES. CONCLUSION: Renal insufficiency and high tacrolimus levels are associated with PRES. A change of immunosuppressive drug should be done after confirmed PRES diagnosis or immediately in case of severe neurological dysfunction to improve neurological outcomes and minimize the risk of early allograft rejection.

Efficacy of pre-exposure prophylaxis to prevent SARS-CoV-2 infection after lung transplantation: a two center cohort study during the omicron era.

PURPOSE: Lung transplant (LTx) recipients are at risk for poor outcomes from coronavirus disease 2019 (COVID-19). The aim of the study was to assess the outcome of patients receiving pre-exposure prophylaxis (PrEP) with tixagevimab and cilgavimab after LTx. METHODS: All LTx recipients with outpatient visits from February 28th to October 31st, 2022 at two German centers were included. Baseline characteristics were recorded and patients followed until November 30rd, 2022. Infections with SARS-CoV-2, disease severity, and COVID-19-associated death were compared between patients with and without PrEP. RESULTS: In total, 1438 patients were included in the analysis, and 419 (29%) received PrEP. Patients receiving PrEP were older and earlier after transplantation, had lower glomerular filtration rates, and lower levels of SARS-CoV-2-S antibodies. In total, 535 patients (37%) developed SARS-CoV-2 infection during a follow-up of median of 209 days. Fewer infections occurred in patients with PrEP during the study period (31% vs. 40%, p = 0.004). Breakthrough SARS-CoV-2 infections after PrEP occurred in 77 patients (19%). In total, 37 infections (8%) were severe or critical. No difference in severity of COVID-19 was observed between patients with and without PrEP. There were 15 COVID-19-associated deaths (n = 1 after PrEP). Compared to matched controls, there was a non-significant difference towards a lower risk for moderate to critical COVID-19 (p 0.184). CONCLUSION: The number of SARS-CoV-2 infections was lower in LTx recipients with PrEP. Despite being at higher risk for worse outcome severity of COVID-19 and associated mortality were similar in patients with and without PrEP.

Outcome of lung transplant recipients infected with SARS-CoV-2/Omicron/B.1.1.529: a Nationwide German study.

PURPOSE: Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is currently the major threat for immunocompromised individuals. The course of COVID-19 in lung transplant recipients in the Omicron era remains unknown. The aim of the study was to assess outcome and associated factors in lung transplant recipients in a German-wide multicenter approach. METHODS: All affected individuals from January 1st to March 20th, 2022 from 8 German centers during the Omicron wave were collected. Baseline characteristics and antiviral measures were associated with outcome. RESULTS: Of 218 patients with PCR-proven SARS-CoV-2 infection 166 patients (76%) received any early (< 7 days) antiviral therapy median 2 (interquartile range 1-4) days after symptom onset. Most patients received sotrovimab (57%), followed by remdesivir (21%) and molnupiravir (21%). An early combination therapy was applied in 45 patients (21%). Thirty-four patients (16%) developed a severe or critical disease severity according to the WHO scale. In total, 14 patients (6.4%) died subsequently associated with COVID-19. Neither vaccination and antibody status, nor applied treatments were associated with outcome. Only age and glomerular filtration rate < 30 ml/min/1.73m2 were independent risk factors for a severe or critical COVID-19. CONCLUSION: COVID-19 due to Omicron remains an important threat for lung transplant recipients. In particular, elderly patients and patients with impaired kidney function are at risk for worse outcome. Prophylaxis and therapy in highly immunocompromised individuals need further improvement.

Mechanical Power Density Predicts Prolonged Ventilation Following Double Lung Transplantation.

Prolonged mechanical ventilation (PMV) after lung transplantation poses several risks, including higher tracheostomy rates and increased in-hospital mortality. Mechanical power (MP) of artificial ventilation unifies the ventilatory variables that determine gas exchange and may be related to allograft function following transplant, affecting ventilator weaning. We retrospectively analyzed consecutive double lung transplant recipients at a national transplant center, ventilated through endotracheal tubes upon ICU admission, excluding those receiving extracorporeal support. MP and derived indexes assessed up to 36 h after transplant were correlated with invasive ventilation duration using Spearman's coefficient, and we conducted receiver operating characteristic (ROC) curve analysis to evaluate the accuracy in predicting PMV (>72 h), expressed as area under the ROC curve (AUROC). PMV occurred in 82 (35%) out of 237 cases. MP was significantly correlated with invasive ventilation duration (Spearman's ρ = 0.252 [95% CI 0.129-0.369], p < 0.01), with power density (MP normalized to lung-thorax compliance) demonstrating the strongest correlation (ρ = 0.452 [0.345-0.548], p < 0.01) and enhancing PMV prediction (AUROC 0.78 [95% CI 0.72-0.83], p < 0.01) compared to MP (AUROC 0.66 [0.60-0.72], p < 0.01). Mechanical power density may help identify patients at risk for PMV after double lung transplantation.

Lung Ultrasound as a Promising Diagnostic Tool for Primary Graft Dysfunction after Lung Transplantation.

PURPOSE: The aim of the study was to evaluate whether the quantification of B-lines via lung ultrasound after lung transplantation is feasible and correlates with the diagnosis of primary graft dysfunction. METHODS: Following lung transplantation, patients underwent daily lung ultrasound on postoperative days 1-3. B-lines were quantified by an ultrasound score based on the number of single and confluent B-lines per intercostal space, using a four-region protocol. The ultrasound score was correlated with the diagnosis of primary graft dysfunction. Furthermore, correlation analyses and receiver operating characteristics analyses taking into account ultrasound score, chest radiographs, and PaO2/FiO2 ratio were performed. RESULTS: A total of 32 patients (91 ultrasound measurements) were included, whereby 10 were diagnosed with primary graft dysfunction. The median B-line score was 5 [IQR: 4, 8]. There was a significant correlation between B-line score and the diagnosis of primary graft dysfunction (r = 0.59, p < 0.001). A significant correlation could also be seen between chest X-rays and primary graft dysfunction (r = 0.34, p = 0.008), but the B-line score showed superiority over chest X-rays with respect to diagnosing primary graft dysfunction in the receiver operating characteristics curves with an area under the curve value of 0.921 versus 0.708. There was a significant negative correlation between B-line score and PaO2/FiO2 ratio (r = -0.41, p < 0.001), but not between chest X-rays and PaO2/FiO2 ratio (r = -0.14, p = 0.279). CONCLUSION: The appearance of B-lines correlated well with primary graft dysfunction and outperformed chest radiographs.

[Pulmonary hypertension associated with lung disease]. / Pulmonale Hypertonie assoziiert mit Lungenerkrankungen.

Lung diseases and hypoventilation syndromes are often associated with pulmonary hypertension (PH). In most cases, PH is not severe. This is defined hemodynamically by a mean pulmonary arterial pressure (PAPm) > 20 mmHg, a pulmonary arterial wedge pressure (PAWP) ≤ 15 mmHg and a pulmonary vascular resistance of ≤ 5 Wood units (WU). Both the non-severe (PVR ≤ 5 WU) and much more the severe PH (PVR > 5 WU) have an unfavorable prognosis.If PH is suspected, it is recommended to primarily check whether risk factors for pulmonary arterial hypertension (PAH, group 1 PH) or chronic thromboembolic pulmonary hypertension (CTEPH, group 4 PH) are present. If risk factors are present or there is a suspicion of severe PH in lung patients, it is recommended that the patient should be presented to a PH outpatient clinic promptly.For patients with severe PH associated with lung diseases, personalized, individual therapy is recommended - if possible within the framework of therapy studies. Currently, a therapy attempt with PH specific drugs should only be considered in COPD patients if the associated PH is severe and a "pulmonary vascular" phenotype (severe precapillary PH, but typically only mild to moderate airway obstruction, no or mild hypercapnia and DLCO < 45 % of predicted value) is present. In patients with severe PH associated with interstitial lung disease phosphodiesterase-5-inhibitors may be considered in individual cases. Inhaled treprostinil may be considered also in non-severe PH in this patient population.