Colitis and Inflammatory Bowel Disease

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.

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

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 Table

DSS Dose Endoscopy Colitis Evaluation Disease Peak Duration  Endpoints 
DSS in drinking water for 6 days Days 3, 5, 7, 12 and 21 Disease severity peaks on days 10-12 and persists until day 21 10-21 Days

Colitis score, Weight, Blood in stool and diarrhea, Histology, Colon length and weight

 

Endoscopy colitis severity scores resulting from acute DSS exposure
Representative photos of the colon (top) and of the corresponding histology (bottom) after acute DSS treatment
Dextran Sulfate Sodium (DSS)-Induced Colitis (Chronic)

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 Table

DSS Dose Endoscopy Colitis Evaluation Disease Peak Duration  Endpoints 
DSS treated drinking water, 5 days on, 7 days off for 3 cycles Four days between day 11 and day 35 Chronic elevation begins day 11 and persists to day 35 35 Days

Colitis score, Weight, Blood in stool and diarrhea, Histology, Colon length and weight

 

Mean percent body weight change
Endoscopy colitis severity scores resulting from chronic DSS exposure
Endoscopy colitis severity scores resulting from chronic DSS exposure
Representative photos of the colon (top) and histology (bottom) after chronic DSS treatment on Day 34
Trinitrobenzene Sulfonic Acid (TNBS)-Induced Colitis (Acute)

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 Table

TNBS Dose (Day 0) Endoscopy Colitis Evaluation Disease Peak Duration  Endpoints 
Single intrarectal dose of TNBS Days 3 and 5 Disease severity peaks at day 3 and persists to day 5 5 Days

Colitis score, Weight, Blood in stool and diarrhea, Histology, Colon length and weight

 

Endoscopy colitis severity scores resulting from acute TNBS exposure
Representative photos of the colon (top) and of the corresponding histology (bottom) after acute TNBS treatment
Oxazolone (OXZ)-Induced Colitis (Acute)

Animals receive a single intrarectal dose of Oxazolone (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 Table

OXZ Dose Endoscopy Colitis Evaluation Disease Peak Duration  Endpoints 
Single intrarectal dose of OXZ Days 3 and 7 Disease severity peaks at day 3 7 Days

Colitis score, Weight, Blood in stool and diarrhea, Histology, Colon length and weight

 

Endoscopy colitis severity scores resulting from acute OXZ exposure
Representative photos of the colon (top) and of the corresponding histology (bottom) after acute OXZ treatment
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 Table

Model Endoscopy Colitis Evaluation Disease Peak Duration  Endpoints 
CD-40mAb Days 3, 7 and 14 Disease severity peaks at day 3, persists through day 7 7-14 Days

Colitis score, Weight, Blood in stool and diarrhea, Histology, Colon length and weight

 

Day 7 Mean Histology Sum Score
Day 7 Endoscopy Colitis Scores
Mean percent weight change
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)
Naïve TH cell Adoptive Transfer Induced 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 sorting methods result in models with comparable disease course, duration, and outcome.

Mice are weighed and monitored daily for signs of disease, and blood can be drawn regularly 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.) can be 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 Table

Model Endoscopy Colitis Evaluation Disease Peak Duration  Endpoints 
Adoptive naïve TH cell transfer Day 14 onwards Progressive 35-56 Days

Colitis score, Weight, Blood in stool and diarrhea, Histology, Colon length and weight

 

Disease induction schematic- Splenocytes are harvested from donor C57Bl/6 mice, and naïve TH cell are sorted by either fluorescent or magnetic methods. Purified naïve TH cells are then transferred into RAG2-/- recipients
Naïve TH cell sort schematic. Representative pre- and post-sort dot plots shown. Whole splenocytes are magnetically sorted to yield a CD4+, CD44-, CD62L+ population (top row). When sorted magnetically, a >97% pure population of CD45RBHIGH cells is obtained (bottom row); equivalent to fluorescent sorting specifically targeting CD45RB.
Animals are monitored daily and their percent weight change relative to day 0 is calculated. Transfer of naïve TH cells (grey line) induces robust weight loss that begins between days 21 and 35 and progressively increases. Transfer of memory TH cells does not induce disease (red line). Treatment with either anti TNFα (blue line) or anti p40 (green line) antibodies has only a mild effect on weight loss.
Intestinal inflammation was assessed by video endoscopy one per week from day 14 onwards. Transfer of naïve TH cells (grey line) induces inflammation that is measureable by day 14 (prior to onset of weight loss) and progressively increases. Transfer of memory TH cells induces transient inflammation that spontaneously resolves (red line). Treatment with either anti TNFα (blue line) or anti p40 (green line) antibodies significantly reduces intestinal inflammation compared to untreated animals.
Engraftment assessment. ~100 µL peripheral blood is collected at regular time points to assess engraftment - transferred cells are identified as CD45+, CD4+ events. Mice that did not receive a transfer have no circulating T cells; mice that did receive a transfer of 0.5x106 naïve TH cells have a robust population of cells in the peripheral blood at day 14, which continues to expand throughout the time course of the model.
Colon histopathology. Inflammation was assessed by histopathology of colon tissue collected at sacrifice. Transfer of naïve TH cells (grey bar) induces robust disease as evidenced by cellular infiltrate, edema, goblet cell depletion, and epithelial damage; the sum score is displayed in the bar chart. Transfer of memory TH cells (red bar) induces only very mild disease that is not statistically different from the naïve controls (yellow bar). Treatment with either anti TNFα (blue bar) or anti p40 (green bar)
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