Colitis/Inflammatory Bowel Disease (IBD)

 

Clinical Background

Inflammatory bowel disease (IBD) consists of ulcerative colitis and Crohn’s disease, progressive, inflammatory disorders of the intestinal tract. IBD has a prevalence of 150-300 per 100,000 and some ethnic groups, such as Ashkenazi Jews, have a particularly high incidence. Ulcerative colitis is limited to the colon and involves diffuse mucosal inflammation, while Crohn’s disease may affect any part of the gastrointestinal tract and is characterized by patchy, transmural inflammation. The fundamental symptom of ulcerative colitis is bloody diarrhea, though abdominal pain, urgency and tenesmus can also occur. Crohn’s disease symptoms typically include abdominal pain, diarrhea and weight loss. There is currently no cure for IBD and treatments aim to control symptoms, encourage remission and avoid relapse; unfortunately, treatments such as corticosteroids and immunosuppressive drugs can cause secondary health problems.

Preclinical Models

Model Description Length Endpoints
DSS-Induced Colitis
(acute/chronic)
Endoscopy colitis scores peak on
day 10, persists through day 21
10-21 days Colitis score, weight, blood in stool and diarrhea, histology, colon length and weight
DSS-Induced Colitis
(chronic/repeated cycles)
Endoscopy colitis scores chronically elevated from day 11 through day 35 35 days
TNBS-Induced Colitis (acute) Colitis severity peaks on day 3, persists through day 5 5 days
OXZ-Induced Colitis (acute) Colitis severity peaks on day 3, persists through day 5 5 days
CD-40 mAb-Induced Colitis Colitis severity peaks on day 3, persists through day 7 7 days
CD45RBᴴᴵᴳᴴ Adoptive T-Cell Transfer Disease onset begins 3-5 weeks after adoptive transfer 8 weeks In addition to traditional endpoints, FACS analysis for further evaluation
CD62L⁺/CD44⁻
Adoptive T-Cell Transfer

 

Acute/Chronic Dextran Sulfate Sodium (DSS)-Induced Colitis

Animals are given DSS-treated drinking water for 6 days and are evaluated daily for survival, body weight, evidence of bloody stool and diarrhea. Endoscopy occurs on days 3, 5, 7, 12 and 21; after animals are sacrificed, colon length and weight are determined and colon histology is performed. In classical IBD models, the measure of mucosal healing has been under-assessed, since the primary endpoint of histology mandates animal sacrifice and precludes the continual tracking of disease course. The use of video endoscopy for these models provides a method for daily visual assessment of the severity of colitis as well as tracking of mucosal healing following a therapeutic intervention.

Study Design

 

Mean Endoscopy Colitis Score

*Endoscopy colitis severity scores resulting from acute DSS exposure

 

DSS_Induced Colitis : Endoscopy and Histology

* Representative photos of the colon (top) and of the corresponding histology (bottom) after acute DSS treatment.

 

 

Chronic Dextran Sulfate Sodium (DSS)-Induced Colitis

Animals are given DSS-treated drinking water according to a 5 days on, 7 days off cycle for a period of 3 cycles and are evaluated daily for survival, body weight, evidence of bloody stool and diarrhea. Endoscopy occurs on days 11, 18, 26 and 35; after animals are sacrificed, colon length and weight are determined and colon histology is performed. In classical IBD models, the measure of mucosal healing has been under-assessed, since the primary endpoint of histology mandates animal sacrifice and precludes the continual tracking of disease course. The use of video endoscopy for these models provides a method for daily visual assessment of the severity of colitis as well as tracking of mucosal healing following a therapeutic intervention.

Study Design

 

Mean Percent Body Weight Change

 

Mean Endoscopic Colitis Scores

Mean Endoscopic Colitis Scores on Day 34

*Endoscopy colitis severity scores resulting from chronic DSS exposure

 

DSS- Induced Colitis: Day 34 Endoscopy and Histology

*Representative photos of the colon (top) and histology (bottom) after chronic DSS treatment.

 

Trinitrobenzene Sulfonic Acid (TNBS)-Induced Colitis

Animals receive a single intrarectal dose of TNBS and are evaluated daily for survival, body weight, evidence of bloody stool and diarrhea. Endoscopy occurs on days 3 and 5; after animals are sacrificed, colon length and weight are determined and colon histology is performed. In classical IBD models, the measure of mucosal healing has been under-assessed, since the primary endpoint of histology mandates animal sacrifice and precludes the continual tracking of disease course. The use of video endoscopy for these models provides a method for daily visual assessment of the severity of colitis as well as tracking of mucosal healing following a therapeutic intervention.

Study Design

 

Mean Endoscopy Colitis Score

*Endoscopy colitis severity scores resulting from acute TNBS exposure

 

TNBS- Induced Colitis : Endoscopy and Histology

*Representative photos of the colon (top) and of the corresponding histology (bottom) after acute TNBS treatment.

 

Acute Oxazalone (OXZ)-Induced Colitis

Animals receive a single intrarectal dose of OXZ and are evaluated daily for survival, body weight, evidence of bloody stool and diarrhea. Endoscopy occurs on days 3, 7 and 10; after animals are sacrificed, colon length and weight are determined and colon histology is performed. In classical IBD models, the measure of mucosal healing has been under-assessed, since the primary endpoint of histology mandates animal sacrifice and precludes the continual tracking of disease course. The use of video endoscopy for these models provides a method for daily visual assessment of the severity of colitis as well as tracking of mucosal healing following a therapeutic intervention.

Study Design

 

Mean Endoscopy Colitis Score

*Endoscopy colitis severity scores resulting from acute OXZ exposure

 

Oxazolone – Induced Colitis : Endoscopy and Histology

*Representative photos of the colon (top) and of the corresponding histology (bottom) after acute OXZ treatment.

 

 

Adoptive Transfer Colitis

In the adoptive transfer model, donor cells are harvested from the spleens of C57Bl/6 mice and naïve TH cells are sorted by a combination of negative magnetic separation and/or flow cytometry. Cells are transferred intra-peritoneally into MHC-matched RAG2-/- recipients at 0.5×106 cells per dose. Naïve T cells are defined as either CD4+, CD45RBHIGH, or CD4+, CD44-, CD62L+; the two models have comparable disease course, duration, and outcome.

Mice are weighed and monitored daily for signs of disease, and blood is drawn every two weeks to assess engraftment. Day 14 CD4+ T cell count in peripheral blood correlates strongly with endpoint weight loss and endoscopy score, and therefore can be used to stratify mice prior to the onset of weight loss. Colonoscopies are performed at regular intervals following the onset of observed morbidity.

Disease onset is expected to occur at 3-5 weeks post-transfer.

Study endpoints include endoscopy colitis scores, weight, blood in stool and diarrhea. In addition, organs (e.g. colon, small intestine, lymph nodes, etc.) are removed and processed for further evaluation by histology and/or cellular characterization by flow cytometry.

Most studies using this model rely on weight loss data alone to determine time of onset and severity of disease. Biomodels provides an extra level of clinically relevant disease evaluation by using serial colonoscopies to visualize extent and severity of colitis during the course of the model, as well as histological examinations of preserved tissues.

Study Design

 

CD45RBHIGH

Naïve TH cell sort schematic. A: Splenocyte prep. B: Comparison of CD4+ enriched population (red) and cells retained in magnetic column (black). C: CD4+ enriched population (red) is approximately 91% pure. D: >96% of the sorted cells (blue) fall within the CD4+, CD45RBHIGH gate. E: Sorted cells (blue) are transferred into recipient RAG2-/- mice at 0.5×106 cells per dose.

 

CD62L+/CD44-

CD62L+/CD44- Naïve TH cell sort schematic. Pre-sort (whole spleen prep) and post-sort dot plots are shown. Splenocytes are magnetically sorted for differential CD62L and CD44 expression by negative selection; CD45RB expression levels shown for comparison. Sorted cells are transferred into recipient RAG2-/- mice at 0.5×106 cells per dose.

 

T cell Engraftment

Representative dots plots showing T cell engraftment following transfer. 100µL peripheral blood was analyzed for CD45 (pan-leukocyte marker) and CD4 (TH marker) to assess naïve TH cell engraftment

 

Percent Weight Change Following Cell Transfer

Mice were weighed daily and the percent weight change was calculated relative to the starting weight on day 0. The two sorting methods provide similar disease outcomes; onset of weight loss and progression to 15% weight loss is more rapid in the CD62L+/CD44- model. n=10 (transfer mice), n=5 (control mice) for each model. Data is presented as mean ±SEM.

 

Adoptive Transfer Colitis: Endoscopy and Histology

Disease is apparent by 5 weeks post transfer as assessed by colonoscopy and histology.
*Mice that received the naïve TH cell transfer (right column) have obvious signs of inflammation, including edema and bleeding, as well as diarrhea.
*H & E staining of colon sections shows a similar pattern including inflammatory cell infiltrate, areas of mucosal necrosis, and edema.
*Mice that received vehicle alone (left column) do not show any signs of pathology throughout the time course of the model.

 

 

CD-40 mAb- Induced Colitis

Animals are given a single intraperitoneal injection of an agonistic CD40 mAb, which is dependent upon tumor necrosis factor-α as well as interleukin-12 p40 and interleukin-23 p40 secretion, for disease induction. The benefit of this particular model is it allows investigators to probe the contribution of inflammatory cytokines in the disease’s progression. Animals are evaluated daily for survival, body weight, evidence of bloody stool and diarrhea. Endoscopy occurs on days 3, 7 and 14; after animals are sacrificed, colon length and weight are determined and colon histology is performed. In classical IBD models, the measure of mucosal healing has been under-assessed, since the primary endpoint of histology mandates animal sacrifice and precludes the continual tracking of disease course. The use of video endoscopy for these models provides a method for daily visual assessment of the severity of colitis as well as tracking of mucosal healing following a therapeutic intervention.

 

Study Design

 
 

 

 

 

CD-40 mAb-Induced Colitis: Day 7 Endoscopy and Histology

*Representative photos of the colon (top) and histology (bottom). Animals administered anti-CD40 antibody had multifocal areas of inflammation (black arrows) associated with epithelial damage (red arrows) and goblet cell depletion. Goblet cell depletion is evident when comparing the number of goblet cells in inflamed areas to the goblet cell density in surrounding, unaffected tissue (dashed arrows)

 

Publications

Computational repositioning of the anticonvulsant topiramate for inflammatory bowel disease
Joel T. Dudley,et al.
Science Translational Medicine DOI: 10.1126/scitranslmed.3002648

Essential role for mast cell tryptase in acute experimental colitis
Matthew J. Hamilton, et al.
Proceedings fo the National Academy of Sciences DOI:10.1073/pnas.100575810