There is a pressing need for effective therapeutics for coronavirus disease 2019 (COVID-19), the respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. The process of drug development is a costly and meticulously paced process, where progress is often hindered by the failure of initially promising leads. To aid this challenge, in vitro human microphysiological systems need to be refined and adapted for mechanistic studies and drug screening, thereby saving valuable time and resources during a pandemic crisis. The SARS-CoV-2 virus attacks the lung, an organ where the unique three-dimensional (3D) structure of its functional units is critical for proper respiratory function. The in vitro lung models essentially recapitulate the distinct tissue structure and the dynamic mechanical and biological interactions between different cell types. Current model systems include Transwell, organoid and organ-on-a-chip or microphysiological systems (MPSs). We review models that have direct relevance toward modeling the pathology of COVID-19, including the processes of inflammation, edema, coagulation, as well as lung immune function. We also consider the practical issues that may influence the design and fabrication of MPS. The role of lung MPS is addressed in the context of multi-organ models, and it is discussed how high-throughput screening and artificial intelligence can be integrated with lung MPS to accelerate drug development for COVID-19 and other infectious diseases.

Malignant pleural effusions are common complications in patients with primary or metastatic cancer to the lungs. In this article, we describe a unique case of a patient with history of diffuse pulmonary metastases from gallbladder adenocarcinoma who acutely developed a bilious pleural effusion following endoscopic retrograde cholangiopancreatography. We believe the bilious pleural effusion (cholethorax or bilothorax) developed as a complication of endoscopic retrograde cholangiopancreatography rather than tumor burden causing a fistula from the biliary tree to the right pleural space. We discuss possible mechanisms of formation of the bilious pleural effusion in our patient and present a literature review of previously reported cases of bilious pleural effusions.