title: Novel in vitro and in vivo models and potential new therapeutics to break the vicious cycle of Cryptosporidium infection and malnutrition.
abstract: BACKGROUND
  Although several animal models of cryptosporidiosis have been reported, most involve genetically or pharmacologically immune-suppressed hosts.
  
  
  METHODS
  We report challenge with excysted (in vitro and in vivo) and unexcysted (in vivo) Cryptosporidium parvum oocysts in human colonic adenocarcinoma (HCT-8) cells and weaned nourished and malnourished C57BL/6 mice, following outcomes of growth rate, stool shedding, and tissue burden. We tested treatment with an oligodeoxynucleotide containing unmethylated CpG motif (CpG-ODN) and alanyl-glutamine in vivo and in vitro.
  
  
  RESULTS
  C. parvum-challenged mice showed prolonged weight loss (>10% over 4 days), robust stool shedding (>3 logs/d over 7 days), and epithelial infection in the ileum, cecum, and colon. Of 2 potential therapeutic compounds evaluated in the model, CpG-ODN reduced body weight loss (to <6% on days 3-7 after challenge), reduced shedding of organisms (by 25% on days 1 and 3 after challenge), and decreased the burden of parasites in the ileum. Alanyl-glutamine showed similar benefits. In vitro findings suggested that effects on the epithelial component of the mucosa probably likely responsible for beneficial effects seen in vivo.
  
  
  CONCLUSIONS
  Weaned mice provide a convenient and reproducible model of cryptosporidial disease, including its vicious cycle with body weight loss and heavier infection with malnutrition, and this model may be useful in exploring innovative therapeutic solutions for this challenging infectious disease.
authors.affiliation: Center for Global Health, Division of Infectious Diseases and International Health, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA.
authors.forename: Lourrany B
authors.initials: LB
authors.lastname: Costa
authors.forename: Francisco Jose
authors.initials: FJ
authors.lastname: Noronha
authors.forename: James K
authors.initials: JK
authors.lastname: Roche
authors.forename: Jesus Emmanuel
authors.initials: JE
authors.lastname: Sevilleja
authors.forename: Cirle A
authors.initials: CA
authors.lastname: Warren
authors.forename: Reinaldo
authors.initials: R
authors.lastname: Oriá
authors.forename: Aldo
authors.initials: A
authors.lastname: Lima
authors.forename: Richard L
authors.initials: RL
authors.lastname: Guerrant
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D003106:Colon / Q000187:drug effects / Q000469:parasitology / Q000473:pathology; D003457:Cryptosporidiosis / Q000150:complications / Q000473:pathology / Q000628:therapy*; D016785:Cryptosporidium parvum / Q000302:isolation & purification / Q000472:pathogenicity*; D016054:DNA, Protozoan / Q000235:genetics / Q000302:isolation & purification; D004151:Dipeptides / Q000627:therapeutic use; D005243:Feces / Q000469:parasitology; D005260:Female; D006801:Humans; D007082:Ileum / Q000187:drug effects / Q000469:parasitology / Q000473:pathology; D044342:Malnutrition / Q000150:complications / Q000469:parasitology* / Q000473:pathology / Q000628:therapy*; D051379:Mice; D008810:Mice, Inbred C57BL; D009838:Oligodeoxyribonucleotides / Q000627:therapeutic use
chemical_list: C408982:CPG-oligonucleotide; D016054:DNA, Protozoan; D004151:Dipeptides; D009838:Oligodeoxyribonucleotides; C054122:alanylglutamine