P72 | a Swab Negative Patient After Sars-Cov-2 Infection Displays Increase of Vegf and Fibronectin Associated With Alterations of Intercellular Junctions

SARS-CoV-2 infection was responsible for the pandemic COrona VIrus Disease (COVID-19) and caused a range of symptoms, including gastrointestinal disorders and abdominal pain, making COVID-19 a multi-organ dysfunction. It is known that the host receptor for SARS-CoV-2, ACE2, is expressed also in the gut, where SARS-CoV-2 could induce vascular damage and immune system dysregulation, similarly to what has been widely described in the lung1. This case report concerns a middle-aged man admitted to the Emergency Department of the University Hospital of Ferrara (Italy) and tested negative to the nose-oropharyngeal swab for SARS-CoV-2 four weeks after recovering from the infection. Due to thrombotic and hemorragic gut conditions, accompanied by severe ulceration, the patient underwent resection of a segment of ileum. Immunohistochemical analyses showed the presence of SARS-CoV-2 nucleocapsid protein and an increased human leukocyte antigen (HLA-G) in the ulcerated ileum portion when compared to the non-ulcerated one2. Moreover, expression and co-expression of Vascular Endothelial Growth Factor (VEGF) and Fibronectin (FN) were analyzed. VEGF expression was increased in the ulcerated ileum portion when compared with control and non-ulcerated ileum. FN staining was progressively increasing in non-ulcerated and ulcerated ileum. By electron microscopy the microvilli alteration of brush border and of intercellular junctions were detected in the ulcerated area but not in other areas of patient’s ileum or in the control sample. The salient aspect of this study is that although the patient was declared negative for SARS-CoV-2 at the respiratory level, SPIKE and SARS-CoV-2 nucleocapsid proteins were still present in the ileum, concentrated in the ulcerated area and parallelled by an increased expression of vascular markers. The ultrastructural analysis gave insights on the morpho-functional effects of SARS-Cov-2 infection on the gut epithelium, indicating that the damage is not limited to vascular structures.