Characterization of the Immune Reaction to Covid-19 Treatment with Dexamethasone: A Narrative Review

Purpose of Study: The spread of SARS-CoV-2 and the resulting Coronavirus Disease 2019 (COVID-19) continues to manifest in individuals in varying severity with limited treatment options available. Despite research efforts put forth in developing therapeutic options for treatment of COVID-19 disease, effective and well understood mechanisms remain limited. Corticosteroid treatment with dexamethasone was shown to be beneficial for those with severe illness early in the pandemic with little understanding of its beneficial mechanism. This narrative review describes the current findings regarding the mechanism of action of dexamethasone treatment in the setting of SARS-CoV-2 infection. Methods Used: A comprehensive search of Embase and PubMed was conducted in consultation with a health sciences librarian. Search terms included (1) COVID-19 (2) dexamethasone (3) animal model and (4) immune response. No limits were used on the search and other reviews were excluded. Search results were screened based on titles and s before being selected for full text review. Outcomes recorded included characterization of the microenvironment of lung tissue following SARS-CoV-2 through cytokine measurement, histopathological staining and analysis of lung tissue, and clinical outcomes such as survival time. Summary of Results: The search resulted in 100 articles. Of these, 8 articles were identified that met the inclusion criteria. Three conducted experiments with Syrian hamsters, two with mice, two with alveolar macrophages, and one study was conducted with human subjects. Dexamethasone treatment was found to diminish inflammatory cytokine levels and preserve the integrity of lung tissue in several animal models and in vitro experiments in the setting of SARS-CoV-2 infection. Dexamethasone treatment was also found to reduce inflammatory cell infiltration of lung tissue infected with SARS-CoV-2. In humans, combination therapy of low dose dexamethasone with spironolactone proved more effective at lowering inflammatory markers than high dose dexamethasone alone. Conclusion(s): Collectively, the articles included in this review support the use of dexamethasone treatment in SARS-CoV-2 infection. Protective effects exhibited with dexamethasone treatment suggest that its action may be linked to the inflammatory nature of COVID-19 disease. Macrophage regulation and diminished inflammatory cytokine levels were hypothesized as possible mechanistic features of dexamethasone action but lacked exact characterization. Further exploration of combination treatment with dexamethasone and its mechanism of action is needed to identify specific and effective therapeutic strategies in the future.

Developing advanced cell culture models to study COVID19-associated pulmonary fibrosis

Patients with severe COVID-19-associated pneumonia are at risk to develop pulmonary fibrosis. To study the underlying mechanisms, we aim to develop advanced cell culture models that reliably reflect COVID-19-related profibrotic microenvironment. To identify key cellular players, we performed pilot immunohistochemistry analysis on lung tissue from COVID-19 patients with fibrosis collected during autopsy. Results revealed diffuse alveolar damage with macrophage infiltration, and myofibroblast accumulation with enriched collagen deposition surrounding the damaged alveoli. To mimic SARS-CoV-2 infection in alveoli, we infected human primary type II alveolar epithelial cells (AEC2) and found enhanced signaling of profibrotic cytokine transforming growth factor beta (TGFbeta) in some donors. To recreate the early fibrotic niche, an alveolar-macrophage-fibroblast (AMF) tri-culture model was established. After infecting AEC2 with SARS-CoV-2 in this AMF model, gene expression analysis provided evidence for fibroblast-to-myofibroblast transition. Furthermore, we found that overexpression of SARS-CoV-2 papain-like protease (PLpro) can promote TGFbeta signaling in HEK293T and A549 cells. After infecting AEC2 with SARS-CoV-2 PLpro lentivirus in the AMF model, we found signs of epithelial-to-mesenchymal transition and fibroblast-to myofibroblast transition. In future studies, we will use a detailed analysis of COVID-19-associated lung fibrosis with other types of lung fibrosis, to further refine COVID-19-related fibrosis models, including lung-on-chip models.

Alveolar macrophages from people with severe eosinophilic asthma show differential antiviral responses to human rhinovirus 16 and SARS-CoV-2

Background: Rhinovirus is the most common trigger for exacerbations of asthma. Alveolar macrophages (AM) are a major site of RV infection and can also be infected by SARS-CoV-2. The pandemic caused by the SARS-CoV-2 raised concerns that patients with severe asthma (SA) would be at particularly high risk of developing severe disease. To date, evidence for poor outcomes in asthma remains limited suggesting a differential immune response to these two viruses. Method(s): Alveolar macrophages (AM) were isolated from bronchoalveolar lavage samples from patients with SA and infected with RV (n=13), SARS-CoV-2 alpha (B.1.1.7) (n=9) and delta (B.1.627.2)(n=8) variants. Antiviral mediators representing NF-KB-induced interferon-driven mRNAs (IL6 and IL8, RIGI and MDA5, respectively) were measured by qPCR, normalised to GAPDH and compared between infected AM and controls. Result(s): RV infected AM showed significant increases in mRNA expression of RIGI (4.39 fold change +/-4.68, p<0.001 vs control), MDA5 (2.96 fold change +/- 2.93, p=0.002 vs control) and IL6 (1.88 fold change +/- 0.98, p=0.006) compared to AM treated with control media alone, whilst IL8 did not significantly change. However, AM infected with SARS-CoV-2 alpha or delta variants showed no difference in levels of antiviral mediators compared to controls. Longitudinal analysis of AMs infected with SARS-CoV-2 alpha or delta variants showed no antiviral response. Conclusion(s): AM from subjects with severe asthma produce a pattern of anti-viral responses following RV infection that is absent when exposed to SARS-CoV-2 variants currently in circulation.

Diagnostic Criteria for COVID-19 Pneumonia in Broncho-Alveolar Lavage Specimens

Introduction: Acute respiratory distress syndrome develops in up to 30% of COVID-19 pneumonia patients. Characterizations of cytologic criteria in bronchoalveolar lavage (BAL) specimens are not well-established. This study evaluates the value of applying several cytologic criteria for the diagnosis of COVID-19 infection in BAL samples. Material(s) and Method(s): We performed a retrospective review of 64 BAL samples collected 6/2020 - 8/2021, divided into two groups: COVID-19 positive group (n=30) and negative group (n=34). Median time from COVID-19 diagnosis to BAL collection was 23 days (range;9-208). The type of inflammation and the cytologic features of alveolar macrophages and respiratory epithelial cells were enumerated. The most common features in COVID-19 positive patients were defined as major diagnostic criteria. Blinded review by a second cytopathologist was performed to predict COVID-19 diagnosis using the defined criteria. Result(s): COVID-19 positive group showed more mixedtype (acute and chronic) inflammation (67% vs 21%;P=0.002), fewer pigment-laden macrophages (22% vs 62%;P=0.001), more enlarged macrophages (85% vs 32%;P<0.001), multi-nucleated macrophages (67% vs 21%;P=0.002) and multi-vacuolated cytoplasm of the macrophages (78% vs 29%;P=0.003) [Figures 1&2]. There was insignificant difference for reactive respiratory epithelial Acta Cytologica 2022;66(suppl 1):1-150 DOI: 10.1159/000527858 12 Exfoliative - Fluids (CSF, Pleural, Peritoneal, etc.) cells (37% vs 24%;P=0.4) and macrophages abundance (63% vs 44%;P=0.5). Identification of diagnostic criteria by a second cytopathologist in COVID-19 positive group, predicted COVID- 19 disease in 27% (>3 major criteria present). After exclusion of cases with remote COVID-19 infection (n=4), the mean interval in days between COVID-19 infection and BAL collection was significantly higher in cases with positive disease prediction (30.5 vs 20.7, P=0.04). Conclusion(s): Features associated with macrophage activation (enlarged and multinucleated macrophages with multi-vacuolated cytoplasm) are prominent in COVID-19 BAL samples. These features may become more recognizable with longer time intervals after infection. Observation of these findings suggest consideration of COVID-19 as the etiology of an individual's pneumonia. (Figure Presented).

AN UNUSUAL CASE OF CYTOMEGALOVIRUS PNEUMONIA IN A PATIENT WITH COVID-19 REQUIRING EXTRACORPOREAL MEMBRANOUS OXYGENATION

SESSION TITLE: COVID-19 Co-Infections SESSION TYPE: Rapid Fire Case Reports PRESENTED ON: 10/19/2022 12:45 pm - 1:45 pm INTRODUCTION: Human cytomegalovirus (CMV) is a herpesvirus with a high prevalence that causes latent disease in immunocompetent hosts. It is an important opportunistic infection with a variety of clinical manifestations, including pneumonia, in immunocompromised patients.[1] CASE PRESENTATION: A 45-year-old man with no past medical history presented with fever and dyspnea and was positive for coronavirus disease 2019 (COVID-19). He developed acute respiratory distress syndrome (ARDS) and was intubated 13 days after presentation, but developed refractory hypoxemia requiring veno-venous extracorporeal membrane oxygenation (ECMO) (cannulated 16 days after presentation). He received a 5-day course of remdesivir and 10 days of dexamethasone 6 mg daily. His course was complicated by acute renal failure requiring continuous renal replacement therapy, septic shock due to a pseudomonal ventilator-associated pneumonia, right ventricular failure, heparin induced thrombocytopenia, and right pneumothorax requiring chest tube thoracostomy. After 4 weeks of ECMO there was lung recovery with ECMO sweep gases <1L/minute, improved radiographic appearance and tidal volumes, and decannulation was anticipated. However, he subsequently developed profound shock of unknown etiology with a rapid worsening of his lung function requiring increased ECMO support. Care was withdrawn at ECMO day 46 due to multiorgan failure. Pathology of his lungs at autopsy showed prominent intranuclear viral inclusions and positive immunohistochemistry in alveolar macrophages consistent with a diagnosis of CMV pneumonia. DISCUSSION: While CMV typically causes latent disease it can reactivate in the setting of immunosuppression and/or critical illness.[1] Patients with severe COVID-19 frequently are treated with immunosuppressive therapies, such as corticosteroids, anti-interluekin-6 therapies, and JAK inhibitors. Due to this immunosuppression, opportunistic infections have been reported in these patients.[2] It can be difficult to differentiate COVID-19 pneumonia from other respiratory infections based on imaging and lab studies alone, especially in patients with prolonged mechanical ventilation and with severe parenchymal disease requiring ECMO support. Little is known about the incidence of CMV and COVID-19 coinfection. There are several cases of biopsy-proven CMV pneumonia in immunocompromised critically ill patients with COVID-19, but this is the first reported case in an immunocompetent patient. CONCLUSIONS: This case highlights the need to maintain a high degree of suspicion for CMV pneumonia in patients with severe COVID-19 pneumonia who receive immunosuppressive therapies. While the diagnosis was made at autopsy in this case, it may be possible to arrive at an earlier diagnosis with CMV polymerase chain reaction (PCR) assays sent from the serum and bronchoalveolar lavage (as lung biopsies are usually impractical in ARDS). Reference #1: de la Hoz RE, Stephens G, Sherlock C. Diagnosis and treatment approaches of CMV infections in adult patients. J Clin Virol. 2002 Aug;25 Suppl 2:S1-12. doi: 10.1016/s1386-6532(02)00091-4. PMID: 12361752. Reference #2: Abdoli A, Falahi S, Kenarkoohi A. COVID-19-associated opportunistic infections: a snapshot on the current reports [published online ahead of print, 2021 Aug 23]. Clin Exp Med. 2021;1-20. doi:10.1007/s10238-021-00751-7 DISCLOSURES: No relevant relationships by Nancy Law No relevant relationships by Mazen Odish No relevant relationships by Robert Owens No relevant relationships by Travis Pollema No relevant relationships by Alyssa Self No relevant relationships by Cassia yi

Exosomes/EVs: CASE SERIES: THE COMBINATION OF RECOMMENDED TREATMENT PROTOCOLS WITH ADD-ON SECRETOME FROM UMBILICAL CORD-DERIVED MESENCHYMAL STEM CELLS (UC-MSCS) THERAPY AS A MEDICAL STRATEGY FOR COVID-19 TREATMENT

Background & Aim: COVID-19 suggested to be treated with pleiotropic agents rather than single-target agents due to its complicated pathophysiology. There are currently no approved effective therapy that can stop the progression of COVID-19. Mesenchymal stem cells and its secretome have been studied in several in vivo lung disease models. The therapeutic application of Secretome therapy has been shown to be efficient in influenza infection, resulting in decreased alveolar fluid clearance and lung injury. This has been linked to attenuation of pro-inflammatory cytokine release, inflammatory cell recruitment, and increased alveolar macrophage content. In this article, we report case series of three COVID-19 patients received an experimental treatment with secretome from umbilical cord-derived mesenchymal stem cells (UC-MSCs) therapy in conjunction with recommended treatment protocols. Methods, Results & Conclusion: Three male patients who were tested positive for COVID-19 are initially presented with mild case of COVID-19 symptoms. The patients were treated with recommended treatment protocols of COVID-19 and add-on secretome from umbilical cord-derived mesenchymal stem cells (UC-MSCs) therapy. In this cases we report the administration of 1 cc and 0,5 cc secretome from UC-MSCs through nasal drop, with 0,5 cc and 0,25 cc for each nostril. Ground Glass Opacity (GGO) were checked by chest CT and the observation stop when patients were symptom-free and tested negative for (Figure Presented)Figs 1 and 2 COVID-19. Significant improvement showed in patients’s respiratory symptoms include GGO profiles, proven by chest CT and no side effects reported. Our report showed that nasal drop of secretome from UC-MSC therapy in patients with mild COVID-19 is safe and well tolerated. No serious therapy-associated adverse event was observed. Further study with more patients and comprehensive biomarker testing is needed to evaluate the efficacy of secretome from UC-MSC therapy to improve long-term treatment outcomes in COVID-19 patients

IMMUNOSUPPRESSION SECONDARY TO SEPSIS AND POSTACUTE CARE SYNDROME LEADING TO LATENT TUBERCULOSIS REACTIVATION

CASE: A 59-year-old Mexican-American man with hypertension and type II diabetes (Hemoglobin A1c 11.5) was admitted for sepsis and Acute Respiratory Distress Syndrome secondary to COVID-19 pneumonia. He was ventilator- dependent for 66 days. His clinical course was complicated by acute renal failure requiring hemodialysis, pulmonary embolism, and recurrent ventilator-associated bacterial pneumonia. He was discharged to a long-term acute care center four months after his initial presentation, but was readmitted two weeks later for abdominal pain and fever. CT abdomen revealed diffuse mesenteric nodular stranding and pelvic ascites concerning for peritoneal carcinomatosis. Biopsy of an omental nodule, however, showed necrotizing granulomatous inflammation and no malignant cells. No cultures were sent from the initial biopsy, so repeat sampling was performed and culture was positive for Mycobacterium tuberculosis complex. Treatment for active tuberculosis was initiated with subsequent recovery. IMPACT/DISCUSSION: Initial infection by tuberculosis occurs in the lungs, where alveolar macrophages encounter and phagocytose the bacteria. The macrophages initiate a cytokine response and recruit lymphocytes to form a granuloma, which segregates the infection within the host. The granuloma is then perpetually maintained by an ongoing immune response that is driven by monocytes and CD-4 T cells. Reactivation of tuberculosis occurs when the ongoing immune response is disrupted. Sepsis has profound and complex effects on the immune system, including marked inhibition of lymphocyte proliferation that leads to reduced levels of B cells, CD-4 T cells, and follicular dendritic cells. Signaling pathways are disrupted without these lymphocytes, which then leads to the dysfunction of the remaining leukocytes. Further, critically ill patients often suffer from post-intensive care unit syndrome. This syndrome is marked by persistent inflammation, which prompts an immunosuppressive response that suppresses T-cell function and leads to T-cell apoptosis. Both sepsis and post-intensive care unit syndrome predispose patients to opportunistic infection by attenuation of the usual immune response. In this particular case, the specific loss of T-cell function in both syndromes allowed this patient's latent tuberculosis to reactivate several months after his initial presentation with sepsis from COVID-19 pneumonia. This case highlights the importance of maintaining a high index of suspicion for opportunistic infection after critical illness. CONCLUSION: Sepsis and post-intensive care unit syndrome disrupted this patient's ability to maintain the immune responses that prevent the progression of latent tuberculosis infection. The diagnosis was delayed due to a lack of awareness of the profound immunosuppression that accompanies and follows critical illness. Providers must recognize these syndromes and the impact they have on immunity in order to diagnose and treat opportunistic infections in a timely manner.

Rapidly Progressive Cellular NSIP in a Young Female Found to Have Antisynthetase Syndrome

Introduction: Antisynthetase syndrome(ASS) is a rare autoimmune disease characterized by myositis, arthritis, cutaneous findings and interstitial lung disease (ILD). In 15-30% cases of ASS, ILD can be the presenting feature making this a very challenging diagnosis to make, especially during the COVID 19 pandemic. We present a unique case of ILD as presenting feature of ASS. Case: A 31 yr old female, never smoker, with asthma and obesity was referred to the pulmonary clinic for dyspnea of 2 months. Dyspnea was on exertion, associated with cough and pleuritic chest pain. Oxygen saturation on exam was 91% at rest and 86% on exertion. PCR and antibodies for COVID was negative. CXR showed bilateral infiltrates. She was treated with several courses of antibiotics and steroids. Her symptoms improved with steroids yet returned when course completed. Chest CT revealed bilateral parenchyma opacities with sparing of the lung apices. This was repeated 3 months after her course of antibiotics and steroids which revealed worsening of ground glass opacities, now diffuse with areas of organizing pneumonia. Bronchoalveolar lavage showed alveolar macrophages with a mixture of acute and chronic inflammatory cells. PFTs revealed severe restrictive lung disease. Infectious work up including bacterial, viral and fungal causes was negative. Complete blood count with differential was normal. B-type natriuretic peptide, creatine kinase, liver function test, basic metabolic panel, HIV and fungal serologies were unrevealing. A rheumatologic work up revealed elevated ESR (48), CRP (6.9), aldolase (48) with positive anti OJ antibodies. She underwent VATs with wedge lung biopsy which revealed cellular non specific interstitial pneumonia (NSIP). She was diagnosed with ASS and started on a gradual taper of high dose steroids and steroid sparing agent Mycophenolate Mofetil. With time her respiratory symptoms improved and she no longer required supplemental oxygen. She was enrolled in pulmonary rehabilitation and encouraged to loose weight as her BMI of 55 could preclude lung transplantation if needed. Discussion: ASS is a rare autoimmune connective tissue disorder characterized by myositis, polyarthritis, cutaneous findings and ILD. It occurs more commonly in women with average age of onset in 50s. ILD has been reported in 69-100% with NSIP being most common followed by cryptogenic organizing pneumonia and UIP. Treatment consists of steroids, with or without a steroid-sparing agent. Timely diagnosis of ASS is imperative for patients presenting with ILD as delay can lead to progression of ILD which serves as a predictor for morbidity and mortality. (Figure Presented).

Patterns of Inflammatory Cell Infiltration in the Lungs of Patients with COVID-19, An Autopsy Study

Background: SARS-CoV-2 causes diffuse alveolar damage, lymphocyte infiltration in the lungs and a cytokine storm. In this study we examined inflammatory cell infiltrates in the lungs of patients with COVID-19. Design: Eighteen COVID-19 autopsy cases (COVID group), 9 non-COVID cases with diffuse alveolar damage (DAD, non-COVID group), and eleven controls without lung diseases were included. Immunostainings for CD3, CD4, CD8, CD68 and broad-spectrum keratins were performed. Results: The average age of COVID-19 patients was 64.4±2.1 years. The most common co-morbidities were hypertension (12/17, 70.6%), diabetes mellitus (9/17, 52.9%) and chronic kidney disease (3/17, 17.6%). The survival duration of 17 patients with available clinical information was 21.2 ± 3.4 days (range 7-53 days) after onset of symptoms. Patients younger than 67 years old (namely young patients thereafter, N=9) survived 26.4 ± 5.9 days after onset of symptoms, which was significantly longer than those greater than 67 years old (namely older patients thereafter, 15.2 ± 1.4 days, N=8, P<0.05). The younger patients had significantly lower platelet counts (107.7 ± 33.2 x 109/L, N=8) than the older ones (224.6 ± 42.4 x 109/L, N=8, P<0.05). Conversely, the younger patients had much higher absolute lymphocyte counts (1.5 ± 0.4 x 109/L, N=7) than the older ones (0.7 ± 0.1 x 109/L, N=8, P<0.05). Interestingly, the patients with low platelet counts (<100 x 109/L) survived longer than those with higher platelet counts (P<0.05). Patients with high troponin levels (>0.2 ng/ml) had shorter survival duration after onset of symptoms (16.8 ± 1.9 days) than those with low troponin levels (30.8 ± 8.0 days, P<0.05). Patients with macrophages >130/HPF, CD3+ T cells >145/HPF, CD8+ T cells <30/HPF and CD8+/CD4+ ratio<1 had a shorter survival time compared to those with macrophages <130/HPF, CD3+ T cells <145/HPF, CD8+ T cells >30/HPF and CD8+/CD4+ ratio>1, respectively. Conclusions: Patients' age > 67 years, blood troponin levels >0.2 ng/ml, platelet count >100 x 109/L, lung macrophages >130/HPF, CD3+ T cells >145/HPF, CD8+ T cells <30/HPF, and CD8/CD4 ratio <1 were associated with shorter survival duration after onset of symptoms.

Diet and Lifestyle Guidelines for Immunomodulation with Reference to Corona Virus Pandemic: A Scientific Statement of the International College of Nutrition

The immune system is comprised of lymph glands, lymph nodes, thymus gland, spleen, bone marrow, lymphocytes, and molecules such as antibodies and cytokines. It has a vast array of functionally different cells such as T and B lymphocytes, macrophages, neutrophils and mast cells. The ontogenesis of the immune system is comprised of the innate immune cells and the adaptive immune cells, where innate immune cells are the first defense mechanisms to respond to pathogenic environmental factors. There are multiple components of the adaptive immune cells, including immunoglobulins (Igs), T-cell receptors (TCR), and major histocompatibility complex (MHC) responsible for adaptive immunity. However, many elements of both the innate and adaptive immune systems are conserved in our bodies. The adaptive immunity is a type of immunity that develops when a person’s immune cells respond to a pathogen such as microorganism or vaccination. Environmental factors such as pathogenic bacteria or viruses, solar exposure, age, exercise, stress, diet, sleep quality and air pollutants can influence the immune system. There may be marked decline in the immune function due to attack of COVID-19. Most patients with mild COVID-19 develop an appropriate immune response that culminates with viral clearance. However, severe disease manifestations have been linked to lymphopenia and immune hyper-responsiveness leading to cytokine storm. It has been observed that in COVID-19, alveolar macrophages are epigenetically altered after inflammation, leading to long-term lung immune-paralysis. Western diets are known to have adverse effects on the immune function. However, Mediterranean-type diets rich in short-and long-chain polyunsaturated fatty acids (PUFA), vegetables, nuts and fruits, dairy products and fish and red wine, due to high content of vitamins, minerals and flavonoids may be useful in boosting immunity. Moderate physical activity may also cause an extensive increase in numerous and varied lipid super-pathway metabolites, including oxidized derivatives called oxylipins. Emerging evidence suggests that dietary supplements containing flavonoids, carotenoids, coenzyme Q10 (CoQ10), vitamins, minerals and antioxidants modulate gene and protein expression and thereby modify endogenous metabolic pathways, and consequently enhance the immunity. Mediterranean-type diet and multiple bioactive nutrients, fatty acids, amino acids, vitamins and minerals as well as moderate physical activity may be crucial for enhancing immunomodulation.

RESPIRABLE POWDER CONTAINING CYCLOSPORINE A LOADED LIPOSOMES AS IMMUNOSUPPRESSIVE AGENT SUITABLE FOR LUNG TRANSPLANT REJECTION AND THE CONTAINMENT OF SEVERE LUNG INFLAMMATION

The work led to the formulation of a powder of calcium phosphate coated liposomes containing cyclosporine A (CsA). The formulation was designed to reduce the dose of CsA to be administered following lung transplantation. Potentially this formulation can be used also to contain the inflammatory process due to SARS-CoV-2. Calcium phosphate (CaP) is a material found in bones and teeth and considered non-toxic and biocompatible and this coating could reduce the recognition by alveolar macrophages and increase the cell uptake. Moreover, CaP is insoluble at physiological pH (7.4), while it solubilizes easily at pH below 5. This could favor drug release in the cell after pinocytosis and in inflamed tissues, while reducing drug release at physiological pH [1]. The liposomes produced were evaluated in terms of size, surface charge and drug loading. The presence of the CaP coating was verified by calcium titration, variation of the zeta potential and by cryogenic transmission electron microscopy (cryo-TEM). The highest loading was obtained in the formulation containing CsA at 7% (w/w). Cholesterol was added to liposomes at two different concentrations in order to improve the stability of the nanostructure and reduce the drug leakage. However, cholesterol did not bring any improvement to the formulation. The inhalation powder produced by spray drying with the best aerosolization performance (fine particle fraction of coated liposomes powder 33.69 - 1.6% and 50.50- 0.6% for the uncoated liposomes powder) was obtained using a 1:3 weight ratio between liposomes and excipients using mannitol as bulking agent and 15% L-leucine. Key Message: This work aimed to develop a respirable dry powder for inhalation containing CsA for the local treatment of lung immune diseases. CsA was efficiently loaded into CaP-coated liposomes and transformed into a respirable powder by spray-drying. The inhaled immunosuppressive product would offer multiple advantages related to drug deposition at the target site. Furthermore, the coating of the liposomes governs the release of the drug which will occur only at only at biological acidic conditions.

Increased expression of angiotensinconverting enzyme 2 (ACE2), TMPRSS2 and furin in idiopathic pulmonary fibrosis (IPF) and lymphangioleiomyomatosis (LAM) patients' lung tissue: Implications for COVID -19

Background and Aims: Patients with chronic lung disease are highly susceptible to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) leading to COVID-19. ACE2 is the main receptor for SARS-CoV-2 attachment. Our previous study reported higher ACE2 levels in smokers and COPD patients. Current study investigates if patients with interstitial lung diseases (ILDs) such as IPF and LAM have elevated levels of ACE2, transmembrane peptidase serine 2 (TMPRSS2) and Furin, increasing their risk for SARS-CoV-2 infection. Methods: Surgically resected lung tissue from IPF, LAM patients and normal controls (NC) was immunostained for ACE2, TMPRSS2 and Furin. Percentage ACE2 expression was measured in small airway (SA) epithelium and alveolar areas. Analysis was done using computer-assisted Image- ProPlus 7.0 software. Results: Compared to NC, the percentage ACE2 expression significantly increased in the SA epithelium of IPF (p<0.01), LAM (p<0.001) and in alveolar areas of IPF (p<0.001), LAM (p<0.001). We also observed elevated TMPRSS2 and Furin expression in the same lung tissue areas of IPF and LAM against NC. There was significant positive correlation between smoking history and ACE2 expression in the IPF for SA epithelium (r=0.81, p<0.05) and alveolar areas (r=0.94, p<0.01). Conclusions: This study has investigated the ACE2, TMPRSS2, and Furin in resected lung tissue of IPF and LAM, which suggests that people with ILDs are at higher risk of developing severe COVID-19 infection. To further understand and provide potential therapeutic targets for ILDs, we need to explore other cell types such as type II pneumocytes, alveolar macrophages and endothelial cells.