ACE2 and COVID-19: We suggest that future investigations performed in patients with COVID-19-associated neuropsychiatric symptoms should include (i) measures of blood-circulating neutral amino acids L-DOPA, tryptamine and β-PEA and (ii) endoscopic intestinal biopsies in order to assess the persistence of SARS-CoV2 in enterocytes, the expression levels of ACE2 and the existence of a local low-grade chronic inflammation.