Intestinal epithelial restitution after TcdB challenge and recovery from Clostridium difficile infection in mice with alanyl-glutamine treatment.
BACKGROUND
Clostridium difficile is an anaerobic bacterium that causes antibiotic-associated diarrhea. It produces toxin A and toxin B (TcdB), which cause injury to the gut epithelium. Glutamine is a fundamental fuel for enterocytes, maintaining intestinal mucosal health. Alanyl-glutamine (AQ) is a highly soluble dipeptide derivative of glutamine. We studied whether administration of AQ ameliorates the effects of TcdB in the intestinal cells and improves the outcome of C. difficile infection in mice.


METHODS
WST-1 proliferation and cell-wounding-migration assays were assessed in IEC-6 cells exposed to TcdB, with or without AQ. Apoptosis and necrosis were assessed using Annexin V and flow cytometry. C57BL/6 mice were infected with VPI 10463 and treated with either vancomycin, AQ, or vancomycin with AQ. Intestinal tissues were collected for histopathologic analysis, apoptosis staining, and determination of myeloperoxidase activity.


RESULTS
AQ increased proliferation in intestinal cells exposed to TcdB, improved migration at 24 and 48 hours, and reduced apoptosis in intestinal cells challenged with TcdB. Infected mice treated with vancomycin and AQ had better survival and histopathologic findings than mice treated with vancomycin alone.


CONCLUSIONS
AQ may reduce intestinal mucosal injury in C. difficile-infected mice by partially reversing the effects of TcdB on enterocyte proliferation, migration, and apoptosis, thereby improving survival from C. difficile infection.
Biomedicine Institute, Federal University of Ceará, Fortaleza, Brazil.
Raphael S
RS
Rodrigues
Renato A C
RA
Oliveira
Yuesheng
Y
Li
Snjezana
S
Zaja-Milatovic
Lourrany B
LB
Costa
Manuel B
MB
Braga Neto
Glynis L
GL
Kolling
Aldo A
AA
Lima
Richard L
RL
Guerrant
Cirle Alcantara
CA
Warren
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001427:Bacterial Toxins / Q000235:genetics* / Q000378:metabolism; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D016360:Clostridioides difficile / Q000187:drug effects* / Q000254:growth & development; D003015:Clostridium Infections / Q000188:drug therapy / Q000382:microbiology; D004151:Dipeptides / Q000494:pharmacology*; D004195:Disease Models, Animal; D020895:Enterocytes / Q000187:drug effects* / Q000378:metabolism / Q000382:microbiology; D007413:Intestinal Mucosa / Q000187:drug effects / Q000382:microbiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009336:Necrosis / Q000188:drug therapy / Q000473:pathology; D051381:Rats; D014640:Vancomycin / Q000494:pharmacology
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004151:Dipeptides; C031815:toxB protein, Clostridium difficile; D014640:Vancomycin; C054122:alanylglutamine