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Background: Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease of unknown etiology and poor prognosis. The alveolar epithelium is damaged, resulting in lung fibrotic lesions. Alveolar type II cells (ATII cells), die from apoptosis and are replaced by fibroblasts. Consequently, there is no regeneration of the epithelium and a progressive decline of pulmonary function. In previous pre-clinical and clinical studies, our group evaluated a new cell therapy using ATII cells, obtaining promising results. The main objective of this study is to investigate mechanisms undertaken by ATII cells that promote fibrosis improvement. Methodology: Lung fibrosis was induced in Sprague-Dawley and Syngeneic Lewis rats by intratracheal instillation of a single dose of Bleomycin (BLM) (2.5 U/kg). On day 14 after BLM administration, animals were transplanted with ATII cells. On day 21 after BLM administration, animals were euthanized to collect ATII cells, fibroblasts, alveolar and interstitial macrophages (AM and IM, respectively), and bronchoalveolar lavage (BAL) fluid. Co-cultures and spheroids experiments between ATII cells and fibroblasts were performed. Tissue samples were analysed for hematoxylin-eosin and Masson’s trichrome staining, and hydroxyproline measurements. Results: Benefits from ATII cells transplantation included enhanced of lungs macroscopic aspect, reducing fibrotic scars; restoration of lung tissue architecture to regular aspect; reduction of hydroxyproline and BAL fluid protein contents; and improvement BAL fluid cellular content, reducing foamy macrophages and white blood cells. Finally, results from cellular interaction assay (spheroids) showed a trend towards apoptosis pathway activation. Unfortunately, results from co-culture experiment were inconclusive, therefore are not presented. Conclusion: ATII cells transplantation improved animals’ health by ameliorating lung fibrotic condition. Mechanisms underlying this improvement need further investig

The use of cell therapies has recently increased for the treatment of pulmonary diseases. Mesenchymal stem/stromal cells (MSCs) and alveolar type II cells (ATII) are the main cell-based therapies used for the treatment of acute respiratory distress syndrome (ARDS). Many pre-clinical studies have shown that both therapies generate positive outcomes; however, the differences in the efficiency of MSCs or ATII for reducing lung damage remains to be studied. We compared the potential of both cell therapies, administering them using the same route and dose and equal time points in a sustained acute lung injury (ALI) model. We found that the MSCs and ATII cells have similar therapeutic effects when we tested them in a hydrochloric acid and lipopolysaccharide (HCl-LPS) two-hit ALI model. Both therapies were able to reduce proinflammatory cytokines, decrease neutrophil infiltration, reduce permeability, and moderate hemorrhage and interstitial edema. Although MSCs and ATII cells have been described as targeting different cellular and molecular mechanisms, our data indicates that both cell therapies are successful for the treatment of ALI, with similar beneficial results. Understanding direct cell crosstalk and the factors released from each cell will open the door to more accurate drugs being able to target specific pathways and offer new curative options for ARDS.

The development of physiological models that reproduce SARS-CoV-2 infection in primary human cells will be instrumental to identify host-pathogen interactions and potential therapeutics. Here, using cell suspensions directly from primary human lung tissues (HLT), we have developed a rapid platform for the identification of viral targets and the expression of viral entry factors, as well as for the screening of viral entry inhibitors and anti-inflammatory compounds. The direct use of HLT cells, without long-term cell culture and in vitro differentiation approaches, preserves main immune and structural cell populations, including the most susceptible cell targets for SARS-CoV-2; alveolar type II (AT-II) cells, while maintaining the expression of proteins involved in viral infection, such as ACE2, TMPRSS2, CD147 and AXL. Further, antiviral testing of 39 drug candidates reveals a highly reproducible method, suitable for different SARS-CoV-2 variants, and provides the identification of new compounds missed by conventional systems, such as VeroE6. Using this method, we also show that interferons do not modulate ACE2 expression, and that stimulation of local inflammatory responses can be modulated by different compounds with antiviral activity. Overall, we present a relevant and rapid method for the study of SARS-CoV-2. The early stages of laboratory identification of therapeutics against pathogens is usually based on the use of immortalized cell lines, as exemplified by many studies screening antivirals against SARS-CoV-2. Cell lines are manipulated for their continuous growth which offers several advantages, however they do not fully reproduce the behavior of primary cells nor the complexity of heterogeneous populations. In this study, we overcome this limitation by using surgical resections to establish human lung tissue (HLT) cell cultures ready for drug evaluation. First, we show that HLT preserves lung cell composition, including the main SARS-CoV-2 cellular target

Ex vivo physiological systems for the study of SARS-CoV-2-host interactions are scarce. We establish a method using primary human lung tissue (HLT) cells for the rapid analysis of cell tropism and identification of therapeutics. Main findings: i) HLT cells preserve main cell subpopulations, including alveolar type-II cells, and expression of SARS-CoV-2 entry factors ACE2, CD147, TMPRSS2 and AXL. ii) HLT cells are readily susceptible to SARS-CoV-2 infection without the need of cell isolation or further cell differentiation. iii) Antiviral testing in HLT cells allows the rapid identification of new drug candidates against SARS-CoV-2 variants, missed by conventional systems. iv) Local inflammation is supported in HLT cells and offers the identification of relevant anti-inflammatory compounds for SARS-CoV-2 infection.

The development of physiological models that reproduce SARS-CoV-2 infection in primary human cells will be instrumental to identify host-pathogen interactions and potential therapeutics. Here, using cell suspensions directly from primary human lung tissues (HLT), we have developed a rapid platform for the identification of viral targets and the expression of viral entry factors, as well as for the screening of viral entry inhibitors and anti-inflammatory compounds. The direct use of HLT cells, without long-term cell culture and in vitro differentiation approaches, preserves main immune and structural cell populations, including the most susceptible cell targets for SARS-CoV-2; alveolar type II (AT-II) cells, while maintaining the expression of proteins involved in viral infection, such as ACE2, TMPRSS2, CD147 and AXL. Further, antiviral testing of 39 drug candidates reveals a highly reproducible method, suitable for different SARS-CoV-2 variants, and provides the identification of new compounds missed by conventional systems, such as VeroE6. Using this method, we also show that interferons do not modulate ACE2 expression, and that stimulation of local inflammatory responses can be modulated by different compounds with antiviral activity. Overall, we present a relevant and rapid method for the study of SARS-CoV-2.

Coronavirus disease 2019 (COVID-19) is a pandemic respiratory disease associated with high morbidity and mortality. Although many patients recover, long-term sequelae after infection have become increasingly recognized and concerning. Among other sequelae, the available data indicate that many patients who recover from COVID-19 could develop fibrotic abnormalities over time. To understand the basic pathophysiology underlying the development of long-term pulmonary fibrosis in COVID-19, as well as the higher mortality rates in patients with pre-existing lung diseases, we compared the transcriptomic fingerprints among patients with COVID-19, idiopathic pulmonary fibrosis (IPF), and chronic obstructive pulmonary disease (COPD) using interactomic analysis. Patients who died of COVID-19 shared some of the molecular biological processes triggered in patients with IPF, such as those related to immune response, airway remodeling, and wound healing, which could explain the radiological images seen in some patients after discharge. However, other aspects of this transcriptomic profile did not resemble the profile associated with irreversible fibrotic processes in IPF. Our mathematical approach instead showed that the molecular processes that were altered in COVID-19 patients more closely resembled those observed in COPD. These data indicate that patients with COPD, who have overcome COVID-19, might experience a faster decline in lung function that will undoubtedly affect global health.

The development of physiological models that reproduce SARS-CoV-2 infection in primary human cells will be instrumental to identify host-pathogen interactions and potential therapeutics. Here, using cell suspensions from primary human lung tissues (HLT), we have developed a platform for the identification of viral targets and the expression of viral entry factors, as well as for the screening of viral entry inhibitors and anti-inflammatory compounds. We show that the HLT model preserves its main cell populations, maintains the expression of proteins required for SARS-CoV-2 infection, and identifies alveolar type II (AT-II) cells as the most susceptible cell targets for SARS-CoV-2 in the human lung. Antiviral testing of 39 drug candidates revealed a highly reproducible system, and provided the identification of new compounds missed by conventional systems such as VeroE6. Using this model, we also show that interferons do not modulate ACE2 expression, and that stimulation of local inflammatory responses can be modulated by different compounds with antiviral activity. Overall, we present a novel and relevant physiological model for the study of SARS-CoV-2.

Idiopathic pulmonary fibrosis (IPF) is a progressively and ultimately fatal lung disease. Previously it has been shown that intratracheal administration of alveolar epithelial type II cells (AE2C) in the animal model of bleomycin-induced pulmonary fibrosis is able to reverse fibrosis and restore surfactant protein levels. However, to date, it has not been evaluated whether these changes involve any improvement in alveolar dynamics. Consequently, the aim of the present work was to study lung physiology after AE2C transplantation at different time points during the development of injury and fibrosis. Lung fibrosis was induced by intratracheal instillation of bleomycin (4U/kg) in rat lungs. The animals were transplanted with AE2C (2.5 × 10 cells/animal) 3 or 7 days after bleomycin instillation. Assessments were done at day 7 and 14 after the induction of fibrosis to plot time dependent changes in lung physiology and mechanics. To assess the pressures and rates at which closed alveoli reopens invasive pulmonary tests using a small-animal mechanical ventilator (Flexivent®, Scireq, Canada) including de-recruitability tests and forced oscillation technique as well as quasi-static pressure volume loops were performed. Afterwards lungs were fixed by vascular perfusion and subjected to design-based stereological evaluation at light and electron microscopy level. AE2C delivered during the lung injury phase (3 days) of the disease are only able to slightly recover the volume of AE2C and volume fraction of LB in AE2C. However, it did not show either positive effects regarding ventilated alveolar surface nor any increase of lung compliance. On the other hand, when AE2C are delivered at the beginning of the fibrotic phase (7 days after bleomycin instillation), an increased ventilated alveolar surface to control levels and reduced septal wall thickness can be observed. Moreover, transplanted animals showed better lung performance, with increased inspiratory capacity and compliance.

The development of physiological models that reproduce SARS-CoV-2 infection in primary human cells will be instrumental to identify host-pathogen interactions and potential therapeutics. Here, using cell suspensions directly from primary human lung tissues (HLT), we have developed a rapid platform for the identification of viral targets and the expression of viral entry factors, as well as for the screening of viral entry inhibitors and anti-inflammatory compounds. The direct use of HLT cells, without long-term cell culture and in vitro differentiation approaches, preserves main immune and structural cell populations, including the most susceptible cell targets for SARS-CoV-2; alveolar type II (AT-II) cells, while maintaining the expression of proteins involved in viral infection, such as ACE2, TMPRSS2, CD147 and AXL. Further, antiviral testing of 39 drug candidates reveals a highly reproducible method, suitable for different SARS-CoV-2 variants, and provides the identification of new compounds missed by conventional systems, such as VeroE6. Using this method, we also show that interferons do not modulate ACE2 expression, and that stimulation of local inflammatory responses can be modulated by different compounds with antiviral activity. Overall, we present a relevant and rapid method for the study of SARS-CoV-2.

Idiopathic pulmonary fibrosis is a fatal disease with no effective or curative treatment options. In recent decades, cell-based therapies using stem cells or lung progenitor cells to regenerate lung tissue have experienced rapid growth in both preclinical animal models and translational clinical studies. In this review, the current knowledge of these cell therapies is summarized. Although further investigations are required, these studies indicate that cell therapies are a promising therapeutic approach for the treatment of idiopathic pulmonary fibrosis.

La fibrosis pulmonar idiopática es una enfermedad progresiva de los pulmones para la que actualmente no disponemos de ninguna terapia. En esta conferencia se explicarán los pasos llevados a cabo en el desarrollo de una nueva teràpia celular para esta enfermedad. El recorrido partirá de la idea original, seguirà con los trabajos experimentales, hasta llegar a las primeras pruebas en pacientes