id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-320350-zeeozmm9	Nisoli, Enzo	COVID-19 and Hartnup disease: an affair of intestinal amino acid malabsorption	2020-07-20		.txt	text/plain	2496	140	44	We hypothesize that SARS-CoV-2 spike protein, binding to intestinal angiotensin-converting enzyme 2, negatively regulates the absorption of neutral amino acids, and this could explain not only the GI, but also systemic disturbances in COVID-19. Altered composition of the gut microbiota (as a consequence of impaired amino acid transport and reduced secretion of antimicrobial peptides by Paneth cells in the small intestine) and changes in innate immunity contribute to the colitis phenotype observed in ACE2 knockout mice [17] . Based on clinical observations and basic research, we hypothesise that, in response to the SARS-CoV-2 binding to intestinal ACE2, the absorption of neutral amino acids is negatively regulated in COVID-19 patients. In malnourished patients or conditions of intestinal amino acid malabsorption, as in the COVID-19 or Hartnup patients, the adaptive immune response cannot be effectively initiated because the absorption of essential energy substrates is impaired by SARS-CoV-2 binding to ACE2.	./cache/cord-320350-zeeozmm9.txt	./txt/cord-320350-zeeozmm9.txt