Middle East Respiratory Syndrome-Coronavirus Infection into Established hDPP4-Transgenic Mice Accelerates Lung Damage Via Activation of the Pro-Inflammatory Response and Pulmonary Fibrosis.

Middle East respiratory syndrome coronavirus (MERS-CoV) infects the lower respiratory airway of humans, leading to severe acute respiratory failure. Unlike human dipeptidyl peptidase 4 (hDPP4), a receptor for MERS-CoV, mouse DPP4 (mDPP4) failed to support MERS-CoV infection. Consequently, diverse transgenic mouse models expressing hDPP4 have been developed using diverse methods, although some models show no mortality and/or only transient and mild-to-moderate clinical signs following MERS-CoV infection. Additionally, overexpressed hDPP4 is associated with neurological complications and breeding difficulties in some transgenic mice, resulting in impeding further studies. Here, we generated stable hDPP4-transgenic mice that were sufficiently susceptible to MERS-CoV infection. The transgenic mice showed weight loss, decreased pulmonary function, and increased mortality with minimal perturbation of overexpressed hDPP4 after MERS-CoV infection. In addition, we observed histopathological signs indicative of progressive pulmonary fibrosis, including thickened alveolar septa, infiltration of inflammatory monocytes, and macrophage polarization as well as elevated expression of profibrotic molecules and acute inflammatory response in the lung of MERS-CoV-infected hDPP4-transgenic mice. Collectively, we suggest that this hDPP4-transgenic mouse is useful in understanding the pathogenesis of MERS-CoV infection and for antiviral research and vaccine development against the virus.

Pulmonary Function and Chest Computed Tomography (CT) Scan Findings After Antifibrotic Treatment for COVID-19-Related Pulmonary Fibrosis.

BACKGROUND Physicians worldwide have been reporting many cases of COVID-19-induced pulmonary fibrosis. We report the case of a 51-year-old Filipino asthmatic woman who developed post-COVID-19 pulmonary fibrosis subsequently treated with Nintedanib. CASE REPORT The patient presented with a 4-day history of flu-like symptoms in September 2020 and was eventually diagnosed with severe COVID-19 pneumonia. Despite receiving Dexamethasone, Tocilizumab, Remdesivir, and multiple antibiotics, there was increasing oxygen requirement, necessitating ICU admission and high-flow nasal cannula (HFNC). An additional course of hydrocortisone was given due to asthma exacerbation, gradually liberating her from the HFNC. A chest CT scan showed extensive parenchymal changes, for which she received methylprednisolone and physical rehabilitation with persistence of respiratory symptoms. After 40 days of hospitalization, she was sent home on oxygen support and Nintedanib. The patient initially had severe dyspnea (Borg Scale 7) with 6-minute walk distance (6MWD) of 295 meters. Pulmonary function showed moderately severe restrictive lung defect at 52% predicted total lung capacity (TLC) and severely reduced DLCO (28% predicted). Chest CT scoring indicated severe lung involvement. One month after Nintedanib treatment, her Borg Scale improved to 4. Her 6MWD, TLC, and DLCO increased to 434 meters, 64% predicted, and 36% predicted, respectively. A chest CT scan showed regressing fibrosis. After 6 months of treatment, her pulmonary function normalized. DLCO remained moderately reduced (59% predicted) but her 6MWD (457 meters) and CT scan results continued to improve. CONCLUSIONS Nintedanib, along with other interventions, may have potentially improved pulmonary function and CT scan findings in a COVID-19 survivor with pulmonary fibrosis 6 months after treatment.

Healing after COVID-19: are survivors at risk for pulmonary fibrosis?

The novel SARS-CoV-2 coronavirus, which is responsible for COVID-19 disease, was first reported in Wuhan, China, in December of 2019. The virus rapidly spread, and the World Health Organization declared a pandemic by March 2020. With millions of confirmed cases worldwide, there is growing concern and considerable debate regarding the potential for coronavirus infection to contribute to an appreciable burden of chronic respiratory symptoms or fibrotic disease among recovered individuals. Because the first case of COVID-19 was documented less than one year ago, data regarding long-term clinical outcomes are not yet available, and predictions for long-term outcome are speculative at best. However, due to the staggering number of cases and the severity of disease in many individuals, there is a critical need to consider the potential long-term implications of COVID-19. This review examines current basic and clinical data regarding fibrogenic mechanisms of viral injury in the context of SARS-CoV-2. Several intersecting mechanisms between coronavirus infection and fibrotic pathways are discussed to highlight factors and processes that may be targetable to improve patient outcome. Reports of post-infection sequelae from previous coronavirus outbreaks are presented toward the goal of improved recognition of potential contributing risk factors for fibrotic disease.

Healing after COVID-19: are survivors at risk for pulmonary fibrosis?

The novel SARS-CoV-2 coronavirus, which is responsible for COVID-19 disease, was first reported in Wuhan, China, in December of 2019. The virus rapidly spread, and the World Health Organization declared a pandemic by March 2020. With millions of confirmed cases worldwide, there is growing concern and considerable debate regarding the potential for coronavirus infection to contribute to an appreciable burden of chronic respiratory symptoms or fibrotic disease among recovered individuals. Because the first case of COVID-19 was documented less than one year ago, data regarding long-term clinical outcomes are not yet available, and predictions for long-term outcome are speculative at best. However, due to the staggering number of cases and the severity of disease in many individuals, there is a critical need to consider the potential long-term implications of COVID-19. This review examines current basic and clinical data regarding fibrogenic mechanisms of viral injury in the context of SARS-CoV-2. Several intersecting mechanisms between coronavirus infection and fibrotic pathways are discussed to highlight factors and processes that may be targetable to improve patient outcome. Reports of post-infection sequelae from previous coronavirus outbreaks are presented toward the goal of improved recognition of potential contributing risk factors for fibrotic disease.

Beyond the clot: perfusion imaging of the pulmonary vasculature after COVID-19.

A compelling body of evidence points to pulmonary thrombosis and thromboembolism as a key feature of COVID-19. As the pandemic spread across the globe over the past few months, a timely call to arms was issued by a team of clinicians to consider the prospect of long-lasting pulmonary fibrotic damage and plan for structured follow-up. However, the component of post-thrombotic sequelae has been less widely considered. Although the long-term outcomes of COVID-19 are not known, should pulmonary vascular sequelae prove to be clinically significant, these have the potential to become a public health problem. In this Personal View, we propose a proactive follow-up strategy to evaluate residual clot burden, small vessel injury, and potential haemodynamic sequelae. A nuanced and physiological approach to follow-up imaging that looks beyond the clot, at the state of perfusion of lung tissue, is proposed as a key triage tool, with the potential to inform therapeutic strategies.

Discharge may not be the end of treatment: Pay attention to pulmonary fibrosis caused by severe COVID-19.

Since December 2019, coronavirus disease (COVID-19) has rapidly swept the world. So far, more than 30 million people have been infected and nearly one million have died. Although the world is still in the stage of COVID-19 pandemic, the treatment of new cases and critically ill patients is the focus of the current work. However, COVID-19 patients lead to pulmonary fibrosis, such a serious threat to the prognosis of complications were also worthy of our attention. First of all, we proposed the possible mechanism of pulmonary fibrosis caused by SARS-CoV-2, based on the published data of COVID-19 ((i) Direct evidence: pulmonary fibrosis was found in autopsy and pulmonary puncture pathology. (ii) Indirect evidence: increased levels of fibrosis-related cytokines[transforming growth factor [TGF]- ß, tumor necrosis factor [TNF]- α, interleukin [IL]-6, etc] in peripheral blood of severe patients.) What is more, we summarized the role of three fibrosis-related signaling pathways (TGF- ß signal pathway, WNT signal pathway and YAP/TAZ signal pathway) in pulmonary fibrosis. Finally, we suggested the therapeutic value of two drugs (pirfenidone and nintedanib) for idiopathic pulmonary fibrosis in COVID-19-induced pulmonary fibrosis.

Coronavirus disease 2019-associated rapidly progressive organizing pneumonia with fibrotic feature: Two case reports.

INTRODUCTION: Pneumonia is one of the most important characteristics of coronavirus disease 2019 (COVID-19) and imaging findings of COVID-19 pneumonia are diverse and change over disease course. However, the detailed clinical course of organizing pneumonia (OP) caused by COVID-19 has not been clarified. PATIENT CONCERNS: A 60-year-old man and a 61-year-old woman diagnosed with mild COVID-19 were admitted to our hospital. Their respiratory symptoms were deteriorating even after initiating treatment with antiviral drugs. DIAGNOSIS: Chest X-rays and computed tomography scan showed a rapid progression of linear consolidation with reversed halo sign, distributed in subpleural and peri-bronchial regions. They also presented with pulmonary fibrosis findings, including traction bronchiectasis and marked lung volume reduction. They were diagnosed with rapidly progressing OP. INTERVENTIONS: They were treated with systemic corticosteroids. OUTCOMES: The patients' imaging findings and respiratory conditions improved rapidly without any adverse effects. CONCLUSION: Physicians should carefully monitor patients with COVID-19, as they can develop rapidly progressive and fibrotic OP, which respond to corticosteroids.

Phosphodiesterase Inhibitors: Could They Be Beneficial for the Treatment of COVID-19?

In March 2020, the World Health Organization declared the severe acute respiratory syndrome corona virus 2 (SARS-CoV2) infection to be a pandemic disease. SARS-CoV2 was first identified in China and, despite the restrictive measures adopted, the epidemic has spread globally, becoming a pandemic in a very short time. Though there is growing knowledge of the SARS-CoV2 infection and its clinical manifestations, an effective cure to limit its acute symptoms and its severe complications has not yet been found. Given the worldwide health and economic emergency issues accompanying this pandemic, there is an absolute urgency to identify effective treatments and reduce the post infection outcomes. In this context, phosphodiesterases (PDEs), evolutionarily conserved cyclic nucleotide (cAMP/cGMP) hydrolyzing enzymes, could emerge as new potential targets. Given their extended distribution and modulating role in nearly all organs and cellular environments, a large number of drugs (PDE inhibitors) have been developed to control the specific functions of each PDE family. These PDE inhibitors have already been used in the treatment of pathologies that show clinical signs and symptoms completely or partially overlapping with post-COVID-19 conditions (e.g., thrombosis, inflammation, fibrosis), while new PDE-selective or pan-selective inhibitors are currently under study. This review discusses the state of the art of the different pathologies currently treated with phosphodiesterase inhibitors, highlighting the numerous similarities with the disorders linked to SARS-CoV2 infection, to support the hypothesis that PDE inhibitors, alone or in combination with other drugs, could be beneficial for the treatment of COVID-19.

SARS-CoV-2 induces transcriptional signatures in human lung epithelial cells that promote lung fibrosis.

BACKGROUND: Severe acute respiratory syndrome (SARS)-CoV-2-induced coronavirus disease-2019 (COVID-19) is a pandemic disease that affects > 2.8 million people worldwide, with numbers increasing dramatically daily. However, there is no specific treatment for COVID-19 and much remains unknown about this disease. Angiotensin-converting enzyme (ACE)2 is a cellular receptor of SARS-CoV-2. It is cleaved by type II transmembrane serine protease (TMPRSS)2 and disintegrin and metallopeptidase domain (ADAM)17 to assist viral entry into host cells. Clinically, SARS-CoV-2 infection may result in acute lung injury and lung fibrosis, but the underlying mechanisms of COVID-19 induced lung fibrosis are not fully understood. METHODS: The networks of ACE2 and its interacting molecules were identified using bioinformatic methods. Their gene and protein expressions were measured in human epithelial cells after 24 h SARS-CoV-2 infection, or in existing datasets of lung fibrosis patients. RESULTS: We confirmed the binding of SARS-CoV-2 and ACE2 by bioinformatic analysis. TMPRSS2, ADAM17, tissue inhibitor of metalloproteinase (TIMP)3, angiotensinogen (AGT), transformation growth factor beta (TGFB1), connective tissue growth factor (CTGF), vascular endothelial growth factor (VEGF) A and fibronectin (FN) were interacted with ACE2, and the mRNA and protein of these molecules were expressed in lung epithelial cells. SARS-CoV-2 infection increased ACE2, TGFB1, CTGF and FN1 mRNA that were drivers of lung fibrosis. These changes were also found in lung tissues from lung fibrosis patients. CONCLUSIONS: Therefore, SARS-CoV-2 binds with ACE2 and activates fibrosis-related genes and processes to induce lung fibrosis.

A review for natural polysaccharides with anti-pulmonary fibrosis properties, which may benefit to patients infected by 2019-nCoV.

Pulmonary fibrosis (PF) is a lung disease with highly heterogeneous and mortality rate, but its therapeutic options are now still limited. Corona virus disease 2019 (COVID-19) has been characterized by WHO as a pandemic, and the global number of confirmed COVID-19 cases has been more than 8.0 million. It is strongly supported for that PF should be one of the major complications in COVID-19 patients by the evidences of epidemiology, viral immunology and current clinical researches. The anti-PF properties of naturally occurring polysaccharides have attracted increasing attention in last two decades, but is still lack of a comprehensively understanding. In present review, the resources, structural features, anti-PF activities, and underlying mechanisms of these polysaccharides are summarized and analyzed, which was expected to provide a scientific evidence supporting the application of polysaccharides for preventing or treating PF in COVID-19 patients.

Is the presence of lung injury in COVID-19 an independent risk factor for secondary lung cancer?

The morbidity and mortality of lung cancer are increasing. The Corona Virus Disease 2019 (COVID-19) is caused by novel coronavirus 2019-nCoV-2, leading to subsequent pulmonary interstitial fibrosis with chronic inflammatory changes, e.g., inflammatory factors repeatedly continuously stimulating and attacking the alveolar epithelial cells. Meanwhile, 2019-nCoV-2 can activate PI3K/Akt and ERK signaling pathways, which can play the double roles as both anti-inflammatory and carcinogenic factors. Moreover, hypoxemia may be developed, resulting in the up-regulation of HIF-1 α expression, which can be involved in the occurrence, angiogenesis, invasion and metastasis of lung cancer. Additionally, the immune system in 2019-nCoV-2 infected cases can be suppressed to cause tumor immune evasion. Therefore, we speculate that COVID-19 may be a risk factor of secondary lung cancer.

The added value of pirfenidone to fight inflammation and fibrotic state induced by SARS-CoV-2 : Anti-inflammatory and anti-fibrotic therapy could solve the lung complications of the infection?

AIM: SARS-CoV-2 infection has been divided by scientific opinion into three phases: the first as asymptomatic or slightly symptomatic and the second and the third with greater severity, characterized by a hyperinflammatory and fibrotic state, responsible for lung lesions, in some cases fatal. The development of antiviral drugs directed against SARS-CoV-2 and effective vaccines is progressing; meanwhile, the best pharmacological objective is related to the management of all the complications caused by this viral infection, mainly controlling the inflammatory and fibrotic state and preventing the infection from moving into the most serious phases. SUBJECT AND METHOD: Describe the scientific rationale related to the use of an antifibrotic therapy with pirfenidone, as monotherapy and/or in combination with anti-inflammatory drugs to manage and control complications of SARS-CoV-2 infection. RESULTS: Based on the scientific literature and epidemiological results and considering the pathophysiological, biological, and molecular characteristics of SARS-CoV-2, an antifibrotic drug such as pirfenidone as monotherapy or in combination with anti-inflammatory drugs can be (acting early, at the right doses and at the right time) therapeutically effective to avoid serious complications during viral infection. The same approach can also be effective as postinfection therapy in patients with residual pulmonary fibrotic damage. Management of inflammation and fibrotic status with a combination therapy of pirfenidone and IL-6 or IL-1 inhibitors could represent a pharmacological synergy with added value. CONCLUSION: In this article, we consider the role of antifibrotic therapy with pirfenidone in patients with SARS-CoV-2 infection on going or in the stage of postinfection with pulmonary fibrotic consequences. The scientific rationale for its use is also described.