Histopathological findings of pericarditis in a patient with multisystem inflammatory syndrome in children associated with COVID-19: A case report

Multisystem inflammatory syndrome in children (MIS-C), which is associated with the novel coronavirus disease 2019 (COVID-19), has been described as an inflammatory complication of exposure to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It carries a risk of serious and lethal complications, including cardiogenic shock. Here, we report the pathological findings of the pericardium in a 10-year-old child with MIS-C, who developed pericarditis-induced cardiac tamponade. In the patient's pericardium, the numbers of infiltrating CD68⁺ macrophages; CD3⁺ , CD4⁺ , and CD8⁺ T cells; and myeloperoxidase⁺ granulocytes were increased, although the number of CD20⁺ B cells was not. These findings provide a clue to understanding the pathophysiology of MIS-C.

The extracellular matrix fibulin 7 maintains epidermal stem cell heterogeneity during skin aging

Tissue stem cells (SCs) divide infrequently as a protective mechanism against internal and external stresses associated with aging. Here, we demonstrate that slow- and fast-cycling SCs in the mouse skin epidermis undergo distinct aging processes. Two years of lineage tracing reveals that Dlx1+ slow-cycling clones expand into the fast-cycling SC territory, while the number of Slc1a3+ fast-cycling clones gradually declines. Transcriptome analysis further indicate that the molecular properties of each SC population are altered with age. Mice lacking fibulin 7, an extracellular matrix (ECM) protein, show early impairments resembling epidermal SC aging, such as the loss of fast-cycling clones, delayed wound healing, and increased expression of inflammation- and differentiation-related genes. Fibulin 7 interacts with structural ECM and matricellular proteins, and the overexpression of fibulin 7 in primary keratinocytes results in slower proliferation and suppresses differentiation. These results suggest that fibulin 7 plays a crucial role in maintaining tissue resilience and epidermal SC heterogeneity during skin aging.

Trajectory of left ventricular geometry and diastolic dysfunction in hereditary transthyretin cardiac amyloidosis

Amyloid transthyretin (ATTR) depositions cause left ventricular (LV) hypertrophy, diastolic dysfunction, and heart failure. The time course of changes in LV geometry and diastolic dysfunction has not been fully reported in patients with ATTR cardiomyopathy. A 79‐year‐old woman with previous myocardial infraction presented with shortness of breath on exertion, and progressive bilateral lower extremity weakness and polyneuropathy. She was diagnosed with Val30Met hereditary ATTR cardiomyopathy by cardiac biopsy and genetic testing. During the past 5 year period, significant LV concentric remodelling with small LV cavity occurred, resulting in an increased LV stiffness and prolonged LV relaxation. This case report highlights the time course of changes in LV geometry and diastolic function and the importance of early diagnosis of ATTR cardiomyopathy.