目的:高达50%的COVID-19病例发生腹泻。尽管如此,病理生理机制尚未确定。
方法:这是使用正常的人类肠样单层进行检查的,该单层顶部暴露于活的SARS-CoV-2或非复制型病毒样颗粒(VLP),这些颗粒带有四种SARS-CoV-2结构蛋白或辐射病毒,所有这些结合并进入肠细胞。
结果:活病毒和VLP增加了多种细胞因子的分泌,并减少了ACE2,NHE3和DRA的mRNA。IL-6加IL-8单独减少NHE3mRNA和蛋白质以及DRAmRNA。无论是VLP还是IL-6加IL-8单独改变Cl-分泌,但是它们一起导致Cl-分泌,它是Ca2+依赖的,CFTR独立,部分被特定的TMEM16A抑制剂阻断,完全由一般的TMEM16家族抑制剂。VLP和辐照病毒,但不是IL-6加上IL-8,在VLP暴露的几分钟内产生Ca2+波,持续了至少60分钟,并通过用三磷酸双磷酸酶预处理来预防;P2Y1受体拮抗剂;和一般的TMEM16家族抑制剂,但不是通过特异性的TMEM16A抑制剂。
结论:COVID-19腹泻的病理生理学似乎是钙依赖性炎症性腹泻的一个独特例子,这是由病毒的直接作用加上病毒诱导的肠上皮细胞因子分泌引起的。
OBJECTIVE: Diarrhea occurs in up to 50% of cases of COVID-19. Nonetheless, the pathophysiologic mechanism(s) have not been determined.
METHODS: This was examined using normal human enteroid monolayers exposed apically to live SARS-CoV-2 or non-replicating virus-like particles (VLPs) bearing the 4 SARS-CoV-2 structural proteins or irradiated virus, all of which bound and entered enterocytes.
RESULTS: Live virus and VLPs increased secretion of multiple cytokines and reduced mRNAs of ACE2, NHE3, and DRA. Interleukin (IL)-6 plus IL-8 alone reduced NHE3 mRNA and protein and DRA mRNA. Neither VLPs nor IL-6 plus IL-8 alone altered Cl- secretion, but together they caused Cl- secretion, which was Ca2+-dependent, CFTR-independent, blocked partially by a specific TMEM16 A inhibitor, and entirely by a general TMEM16 family inhibitor. VLPs and irradiated virus, but not IL-6 plus IL-8, produced Ca2+ waves that began within minutes of VLP exposure, lasted for at least 60 minutes, and were prevented by pretreatment with apyrase, a P2Y1 receptor antagonist, and general TMEM16 family inhibitor but not by the specific TMEM16A inhibitor.
CONCLUSIONS: The pathophysiology of COVID-19 diarrhea appears to be a unique example of a calcium-dependent inflammatory diarrhea that is caused by direct viral effects plus the virus-induced intestinal epithelial cytokine secretion.