Related Experiment Video
Updated: Mar 16, 2026
Ex Vivo Organoid Model of Adenovirus-Cre Mediated Gene Deletions in Mouse Urothelial Cells
Published on: May 5, 2022
Ex Vivo and In Vivo Mice Models to Study Blastocystis spp. Adhesion, Colonization and Pathology: Closer to Proving
Sitara S R Ajjampur1, Chin Wen Png1, Wan Ni Chia1
1Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, National University of Singapore, 5 Science Drive 2, Singapore, 117545.
Abstract:
Blastocystis spp. are widely prevalent extra cellular, non-motile anerobic protists that inhabit the gastrointestinal tract. Although Blastocystis spp. have been associated with gastrointestinal symptoms, irritable bowel syndrome and urticaria, their clinical significance has remained controversial. We established an ex vivo mouse explant model to characterize adhesion in the context of tissue architecture and presence of the mucin layer. Using confocal microscopy with tissue whole mounts and two axenic isolates of Blastocystis spp., subtype 7 with notable differences in adhesion to intestinal epithelial cells (IEC), isolate B (ST7-B) and isolate H (more adhesive, ST7-H), we showed that adhesion is both isolate dependent and tissue trophic. The more adhesive isolate, ST7-H was found to bind preferentially to the colon tissue than caecum and terminal ileum. Both isolates were also found to have mucinolytic effects. We then adapted a DSS colitis mouse model as a susceptible model to study colonization and acute infection by intra-caecal inoculation of trophic Blastocystis spp.cells. We found that the more adhesive isolate ST7-H was also a better colonizer with more mice shedding parasites and for a longer duration than ST7-B. Adhesion and colonization was also associated with increased virulence as ST7-H infected mice showed greater tissue damage than ST7-B. Both the ex vivo and in vivo models used in this study showed that Blastocystis spp. remain luminal and predominantly associated with mucin. This was further confirmed using colonic loop experiments. We were also successfully able to re-infect a second batch of mice with ST7-H isolates obtained from fecal cultures and demonstrated similar histopathological findings and tissue damage thereby coming closer to proving Koch's postulates for this parasite.
Insights
Blastocystis parasites, common in the gut, show varied adhesion to intestinal cells. A more adhesive subtype (ST7-H) caused greater tissue damage in a mouse model, suggesting a role in infection.
Area of Science:
- Gastroenterology
- Parasitology
- Microbiology
Background:
- Blastocystis spp. are prevalent anaerobic protists in the gastrointestinal tract.
- Their clinical significance and role in diseases like IBS remain controversial.
- Understanding Blastocystis adhesion and colonization is crucial for assessing pathogenicity.
Purpose of the Study:
- To characterize Blastocystis spp. adhesion to intestinal tissue using ex vivo and in vivo models.
- To compare the adhesion, colonization, and virulence of different Blastocystis subtypes.
- To investigate the interaction of Blastocystis with the mucin layer and intestinal epithelium.
Main Methods:
- Established an ex vivo mouse explant model to study Blastocystis adhesion to intestinal tissue.
- Utilized confocal microscopy to visualize parasite-tissue interactions.
- Employed a DSS colitis mouse model for in vivo colonization and infection studies.
Main Results:
- Adhesion of Blastocystis spp. to intestinal epithelial cells (IEC) is isolate-dependent and tissue-specific.
- A highly adhesive isolate (ST7-H) preferentially bound to the colon and demonstrated mucinolytic activity.
- ST7-H showed enhanced colonization and virulence in vivo, leading to greater tissue damage compared to a less adhesive isolate (ST7-B).
Conclusions:
- Blastocystis spp. primarily remain luminal and associate with the mucin layer.
- Parasite adhesion and colonization capabilities correlate with virulence.
- Findings contribute to understanding Blastocystis pathogenicity and approach Koch's postulates.
