Abstract
Background: Children and older adults with coronavirus disease 2019 (COVID-19) display a distinct spectrum of disease severity yet the risk factors aren’t well understood. We sought to examine the expression pattern of angiotensin-converting enzyme 2 (ACE2), the cell-entry receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and the role of lung progenitor cells in children and older patients.
Methods: We retrospectively analyzed clinical features in a cohort of 299 patients with COVID-19. The expression and distribution of ACE2 and lung progenitor cells were systematically examined using a combination of public single-cell RNA-seq data sets, lung biopsies, and ex vivo infection of lung tissues with SARS-CoV-2 pseudovirus in children and older adults. We also followed up patients who had recovered from COVID-19.
Results: Compared with children, older patients (>50 years.) were more likely to develop into serious pneumonia with reduced lymphocytes and aberrant inflammatory response (P = .001). The expression level of ACE2 and lung progenitor cell markers were generally decreased in older patients. Notably, ACE2 positive cells were mainly distributed in the alveolar region, including SFTPC positive cells, but rarely in airway regions in the older adults (P < .01). The follow-up of discharged patients revealed a prolonged recovery from pneumonia in the older (P < .025).
Conclusions: Compared to children, ACE2 positive cells are generally decreased in older adults and mainly presented in the lower pulmonary tract. The lung progenitor cells are also decreased. These risk factors may impact disease severity and recovery from pneumonia caused by SARS-Cov-2 infection in older patients.
Keywords: ACE2 expression and distribution; COVID-19; disease severity; lung progenitor cells; patients’ ages.
【저자키워드】 COVID-19, disease severity, lung progenitor cells, ACE2 expression and distribution, patients’ ages., 【초록키워드】 coronavirus disease, SARS-CoV-2, ACE2, coronavirus, Pneumonia, children, Infection, lung, risk factor, angiotensin-converting enzyme 2, airway, lymphocyte, Adults, Cohort, older patient, Region, biopsies, single-cell RNA-seq, Patient, Follow-up, SARS-CoV-2 pseudovirus, receptor, distribution, ACE2 expression, disease, expression, clinical feature, Combination, Inflammatory response, older patients, discharged patient, data sets, acute respiratory syndrome, Older, expression level, positive cells, lung tissue, expression pattern, SFTPC, alveolar, pulmonary tract, ex vivo infection, analyzed, develop, examined, caused, reduced, cell marker, patients with COVID-19, positive cell, progenitor cell, 【제목키워드】 ACE2, Impact, progenitor,