We collected plasma cortisol concentrations in nine critically ill patients with COVID-19. ACE2 receptor and TMPRSS2 serine protease were colocalized in adrenocortical cells in zona fasciculata and zona reticularis. Results: High percentage of critically ill patients with SARS-COV-2 infection in the study were treated with vasopressors. We retrospectively analyzed serum cortisol levels in critically ill patients with or without COVID-19. ACE2 and TMPRSS2 expression was examined in human adrenal glands by immunohistochemical staining. Methods: We summarized the clinical features of COVID-19 reported in currently available observational studies. The aim of this article is to investigate whether SARS-CoV-2 can attack the adrenal cortex to aggravate the relative adrenal insufficiency. Recent study showed that dexamethasone can reduce COVID-19 deaths by up to one third in critically ill patients. The therapeutic effect of dexamethasone may be related to its ability to improve cortical function. 5Department of Critical Care Medicine, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, Chinaīackground: The majority of the critically ill patients may have critical illness-related corticosteroid insufficiency (CIRCI).4Department of Physiology, Navy Medical University, Shanghai, China.3Department of Respiratory and Critical Care Medicine, Shanghai Public Health Clinical Center Affiliated to Fudan University, Shanghai, China.2Department of Pathology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.1Department of Anesthesiology and Surgical Intensive Care Unit, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.Yanfei Mao 1†, Bo Xu 1†, Wenbin Guan 2†, Dunfeng Xu 1, Feng Li 3, Rongrong Ren 1, Xiaoyan Zhu 4*, Yuan Gao 5* and Lai Jiang 1*

Adrenal cortex cortisol