SARS-CoV-2 has resulted in numerous cases of Coronavirus Disease 2019 (COVID-19) worldwide. In addition to fever and respiratory symptoms, digestive symptoms also are observed in some patients with COVID-19. Angiotensin-converting enzyme 2 (ACE2) was reported to be the receptor for SARS-CoV-2. The aim of this study was to comprehensively investigate the digestive symptoms that occur in COVID-19 patients, and the potential pathogenic route of the SARS-CoV-2 infection in digestive tract organs (from the oral cavity to the gastrointestinal tract). We investigated the digestive symptoms of 48 patients with COVID-19 and explored ACE2 expression in digestive tract and lung cancers, based on a series of bulk and single-cell RNA sequencing data obtained from public databases. We found that 25% (12/48) of the patients with COVID-19 suffered from digestive symptoms, among which pharyngalgia (7/48) was the most common manifestation, followed by diarrhea (3/48), anorexia (3/48), and nausea (1/48). The bulk tissue RNA sequencing analysis indicated that digestive tract organs had higher ACE2 expression levels compared to the lung, and the expression of ACE2 in the lung increased with age. Single-cell RNA-Seq results showed that the ACE2-positive-cell ratio in digestive tract organs was significantly higher compared to the lung. ACE2 expression was higher in tumor cells compared to normal control (NC) tissues. While in gastric tissues, ACE2 expression gradually increased from chronic gastritis to metaplasia, to early cancer. Our data might provide a theoretical basis for screening the SARS-CoV-2 susceptible population and for the clinical classification of treatment of patients with COVID-19.

SARS-CoV-2 已导致全球出现大量 2019 年冠状病毒病 (COVID-19) 病例。除了发烧和呼吸道症状外，一些 COVID-19 患者还出现消化道症状。据报道，血管紧张素转换酶 2 (ACE2) 是 SARS-CoV-2 的受体。本研究的目的是全面调查COVID-19患者出现的消化道症状，以及消化道器官（从口腔到胃肠道）SARS-CoV-2感染的潜在致病途径。我们根据从公共数据库获得的一系列批量和单细胞 RNA 测序数据，调查了 48 名 COVID-19 患者的消化道症状，并探讨了消化道癌和肺癌中的 ACE2 表达。我们发现25%（12/48）的COVID-19患者出现消化道症状，其中咽痛（7/48）是最常见的表现，其次是腹泻（3/48）、厌食（3/48） ）和恶心（1/48）。大块组织RNA测序分析表明，消化道器官的ACE2表达水平高于肺，且肺中ACE2的表达随着年龄的增长而增加。单细胞RNA-Seq结果显示，消化道器官中ACE2阳性细胞的比例明显高于肺部。与正常对照（NC）组织相比，肿瘤细胞中 ACE2 的表达较高。而在胃组织中，从慢性胃炎到化生，再到早期癌，ACE2表达逐渐升高。我们的数据可能为筛查 SARS-CoV-2 易感人群和 COVID-19 患者的临床分类治疗提供理论依据。