Pathological granuloma fibrosis induced by agar-embedded Mycobacterium abscessus in C57BL/6JNarl mice.

Introduction: Pulmonary granuloma diseases caused by Mycobacterium abscessus (M. abscessus) have increased in past decades, and drug-resistance in this pathogen is a growing public health concern. Therefore, an animal model of chronic granuloma disease is urgently needed. Methods: In this study, M. abscessus embedded within agar beads (agar-AB) was used to develop such a model in C57BL/6JNarl mice. Results: Chronic infection was sustained for at least 3 months after agar-AB infection, visible granulomas spread in the lungs, and giant cells and foamy cells appeared in the granulomas. More importantly, pulmonary fibrosis progressed for 3 months, and collagen fibers were detected by Masson trichrome staining. Further, inducible nitric oxide synthase (iNOS) was highly expressed within the alveolar space, and the fibrosis-mediator transforming growth factor beta (TGF-ß) began to be expressed at 1 month. Hypoxia-inducible factor (HIF-1α) expression also increased, which aided in normalizing oxygen partial pressure. Discussion: Although the transient fibrosis persisted for only 3 months, and the pulmonary structure resolved when the pathogen was cleard, this pulmonary fibrosis model for M. abscessus infection will provide a novel test platform for development of new drugs, regimens, and therapies.

Characterization of Virus Replication, Pathogenesis, and Cytokine Responses in Syrian Hamsters Inoculated with SARS-CoV-2.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel coronavirus which caused a global respiratory disease pandemic beginning in December 2019. Understanding the pathogenesis of infection and the immune responses in a SARS-CoV-2-infected animal model is urgently needed for vaccine development. METHODS: Syrian hamsters (Mesocricetus auratus) were intranasally inoculated with 105, 5×105, and 106 TCID50 of SARS-CoV-2 per animal and studied for up to 14 days. Body weight, viral load and real-time PCR amplification of the SARS-CoV-2 N gene were measured. On days 3, 6 and 9, lung, blood, liver, pancreas, heart, kidney, and bone marrow were harvested and processed for pathology, viral load, and cytokine expression. RESULTS: Body weight loss, increased viral load, immune cell infiltration, upregulated cytokine expression, viral RNA, SARS-CoV-2 nucleoprotein, and mucus were detected in the lungs, particularly on day 3 post-infection. Extremely high expression of the pro-inflammatory cytokines MIP-1 and RANTES was detected in lung tissue, as was high expression of IL-1ß, IL-6, IL-12, and PD-L1. The glutamic oxalacetic transaminase/glutamic pyruvic transaminase (GOT/GPT) ratio in blood was significantly increased at 6 days post-infection, and plasma amylase and lipase levels were also elevated in infected hamsters. CONCLUSION: Our results provide new information on immunological cytokines and biological parameters related to the pathogenesis and immune response profile in the Syrian hamster model of SARS-CoV-2 infection.

Sclerosing mucoepidermoid carcinoma with eosinophilia of thyroid gland in a male patient: a case report and literature review.

Sclerosing mucoepidermoid carcinoma with eosinophilia (SMECE) was first described by Chan et al in 1991. It is characterized by nest or strands of epidermoid tumor cells with squamous differentiation, rare mucous cells, prominent sclerotic stroma, eosinophilic and lymphoplasmacytic infiltration, and a background of chronic lymphocytic thyroiditis in the non-neoplastic thyroid gland. It is important to recognize SMECE of thyroid and differentiate it from squamous cell carcinoma or other neoplasms with squamous differentiation/metaplasia. In published cases, the SMECE of thyroid gland predominantly occurs in women. We report a case of SMECE of thyroid in a 45-year-old male patient. All cases in male patients were Caucasian described in English literature, and our case is the first one in Asian.