Earliest histopathological changes in COVID-19 pneumonia with comprehensive gene expression analyses:: A case series study

• Koji Okudela ^[1] ; Hiroyuki Hayashi ^[2] ; Yukihiro Yoshimura ^[2] ; Hiroaki Sasaki ^[2] ; Nobuyuki Miyata ^[2] ; Hiromichi Iwashita ^[1] ; Toshiaki Kataoka ^[1] ; Mai Matsumura ^[1] ; Hideaki Mitsui ^[1] ; Yasuyoshi Hatayama ^[1] ; Tsuneo Yamashiro ^[1] ; Akihide Ryo ^[1] ; Natsuo Tachikawa ^[2]
  1. [1] Yokohama City University

     Yokohama City University

     Naka Ku, Japón

     
  2. [2] Yokohama Municipal Citizen’s Hospital, Yokohama, Japan
• Localización: Histology and histopathology: cellular and molecular biology, ISSN-e 1699-5848, ISSN 0213-3911, Vol. 38, Nº. 6, 2023, págs. 623-636
• Idioma: inglés
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• Resumen

  • Aims. In COVID-19 pneumonia, early detection and appropriate treatment are essential to prevent severe exacerbation. Therefore, it is important to understand the initiating events of COVID-19 pneumonia. However, at present, the literature about early stage disease has been very limited. Here, we investigated the earliest histopathological changes and gene expression profiles associated with COVID-19 pneumonia.

    Methods and Results. We carefully examined 25 autopsied cases with different clinical courses. Dilation of capillaries and edematous thickening of the alveolar septa were found even in areas that macroscopically looked almost normal. Pneumocytes, histocytes/ macrophages, and vascular endothelial cells were immunohistochemically positive for tissue factor, which is an important early responder to tissue injuries.

    Comprehensive gene expression analyses revealed that those lesions presented differential profiles compared to those of control lungs and were associated with a significant upregulation of the lysosomal pathway.

    Conclusions. Alveolar capillary dilation and edematous thickening may be the earliest histopathological change detected in COVID-19 pneumonia. Intensive investigations of such lesions may lead to an understanding of the initiating event of not only COVID-19 pneumonia but also of general diffuse alveolar damage.