Imaging of intestinal lymphocyte homing by means of pinhole SPECT in a TNBS colitis mouse model

Chemically Induced Colitis-Associated Cancer Models in Rodents for Pharmacological Modulation: A Systematic Review

Animal models for colitis-associated colorectal cancer (CACC) represent an important tool to explore the mechanistic basis of cancer-related inflammation, providing important evidence that several inflammatory mediators play specific roles in the initiation and perpetuation of colitis and CACC. Although several original articles have been published describing the CACC model in rodents, there is no consensus about the induction method. This review aims to identify, summarize, compare, and discuss the chemical methods for the induction of CACC through the PRISMA methodology.

METHODS

We searched MEDLINE via the Pubmed platform for studies published through March 2021, using a highly sensitive search expression. The inclusion criteria were only original articles, articles where a chemically-induced animal model of CACC is described, preclinical studies in vivo with rodents, and articles published in English.

RESULTS

Chemically inducible models typically begin with the administration of a carcinogenic compound (as azoxymethane (AOM) or 1,2-dimethylhydrazine (DMH)), and inflammation is caused by repeated cycles of colitis-inducing agents (such as 2,4,6-trinitrobenzenesulfonic acid (TNBS) or dextran sulfate sodium (DSS)). The strains mostly used are C57BL/6 and Balb/c with 5-6 weeks. To characterize the preclinical model, the parameters more used include body weight, stool consistency and morbidity, inflammatory biomarkers such as tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-1β, angiogenesis markers such as proliferating cell nuclear antigen (PCNA), marker of proliferation Ki-67, and caspase 3, the presence of ulcers, thickness or hyperemia in the colon, and histological evaluation of inflammation.

CONCLUSION

The AOM administration seems to be important to the CACC induction method, since the carcinogenic effect is achieved with just one administration. DSS has been the more used inflammatory agent; however, the TNBS contribution should be more studied, since it allows a reliable, robust, and a highly reproducible animal model of intestinal inflammation.

Molecular Magnetic Resonance Imaging with Contrast Agents for Assessment of Inflammatory Bowel Disease: A Systematic Review

Background and Aims

Magnetic resonance imaging (MRI) has taken an important role in the diagnosis of inflammatory bowel diseases (IBD). In the wake of current advances in nanotechnology, the drug delivery industry has seen a surge of nanoparticles advertising high specificity in target imaging. Given the rapid development of the field, this review has assembled related articles to explore whether molecular contrast agents can improve the diagnostic capability on gastrointestinal imaging, especially for IBD.

Methods

Relevant articles published between 1998 and 2018 from a literature search of PubMed and EMBASE were reviewed. Data extraction was performed on the studies' characteristics, experimental animals, modelling methods, nanoparticles type, magnetic resonance methods, and means of quantitative analysis.

Results

A total of 8 studies were identified wherein the subjects were animals, and all studies employed MR equipment. One group utilized a perfluorocarbon solution and the other 7 groups used either magnetic nanoparticles or gadolinium- (Gd-) related nanoparticles for molecular contrast. With ultrasmall superparamagnetic iron oxide (USPIO) particles and Gd-related nanoparticles, signal enhancements were found in the mucosa or with focal lesion of IBD-related model in T1-weighted images (T1WI), whereas superparamagnetic iron oxide (SPIO) particles showed a signal decrease in the intestinal wall of the model in T1WI or T2-weighted images. The signal-to-noise ratio (SNR) was employed to analyze bowel intensity in 3 studies. And the percentage of normalized enhancement was used in 1 study for assessing the severity of inflammation.

Conclusion

Molecular MRI with contrast agents can improve the early diagnosis of IBD and quantitate the severity of inflammation in experimental studies.

Preclinical Study in Vivo for New Pharmacological Approaches in Inflammatory Bowel Disease: A Systematic Review of Chronic Model of TNBS-Induced Colitis

The preclinical studies in vivo provide means of characterizing physiologic interactions when our understanding of such processes is insufficient to allow replacement with in vitro systems and play a pivotal role in the development of a novel therapeutic drug cure. Chemically induced colitis models are relatively easy and rapid to develop. The 2,4,6-trinitrobenzenesulfonic acid (TNBS) colitis model is one of the main models in the experimental studies of inflammatory bowel disease (IBD) since inflammation induced by TNBS mimics several features of Crohn’s disease. This review aims to summarize the existing literature and discuss different protocols for the induction of chronic model of TNBS-induced colitis. We searched MEDLINE via Pubmed platform for studies published through December 2018, using MeSH terms (Crohn Disease.kw) OR (Inflammatory Bowel Diseases.kw) OR (Colitis, Ulcerative.kw) AND (trinitrobenzenesulfonic acid.kw) AND (disease models, animal.kw) AND (mice.all). The inclusion criteria were original articles, preclinical studies in vivo using mice, chronic model of colitis, and TNBS as the inducer of colitis and articles published in English. Chronic TNBS-induced colitis is made with multiple TNBS intrarectal administrations in an average dose of 1.2 mg using a volume lower than 150 μL in 50% ethanol. The strains mostly used are Balb/c and C57BL/6 with 5–6 weeks. To characterize the preclinical model the parameters more used include body weight, stool consistency and morbidity, inflammatory biomarkers like interferon (IFN)-γ, myeloperoxidase (MPO), tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-10, presence of ulcers, thickness or hyperemia in the colon, and histological evaluation of the inflammation. Experimental chronic colitis is induced by multiple rectal instillations of TNBS increasing doses in ethanol using Balb/c and C57BL/6 mice.

Longitudinal PET/CT evaluation of TNBS-induced inflammatory bowel disease rat model

Inflammatory bowel disease (IBD) is a group of chronic disorders of the gastrointestinal tract, which two main types are Crohn's disease and ulcerative colitis. It has multifactorial etiologies, being essential the use of animal models and disease activity measures to develop new therapies. With this aim, the use of animal models in combination with non-invasive molecular imaging can play an important role in the development of new treatments. In this study, IBD was induced in rats using 2,4,6-trinitrobenzenesulfonic acid (TNBS) and longitudinal [¹⁸F]FDG PET/CT scans were conducted to assess disease progression post-TNBS administration. Afterwards, [¹⁸F]FDG PET/CT scans were carried out after treatment with methylprednisolone to validate the model. In non-treated rats, SUV_max (Standardized Uptake Value) rapidly increased after IBD induction, being particularly significant (p < 0.01) on days 7-13 after induction. There were no significant differences between non-treated and treated IBD rats from days 0-3. Nevertheless, treated IBD rats showed a significant decrease in SUV_max between days 7-13 (p < 0.01). Histological examination showed descending and transverse colon as the most affected regions. There was a moderate (R² = 0.61) and strong (R² = 0.82) correlation of SUV_max with Nancy grade (parameter for histological assessment of disease activity) and weight changes, respectively. In this study, we have performed the first longitudinal [¹⁸F]FDG PET/CT assessment of TNBS-induced IBD in rats, demonstrating the potential role of preclinical molecular imaging for the evaluation of new therapies in combination with IBD rat models.

Preparation of gelatin nanospheres incorporating quantum dots and iron oxide nanoparticles for multimodal cell imaging

The objective of this study is to prepare a multimodal probe which can simultaneously visualize cells by optical and magnetic resonance (MR) imaging modalities. Gelatin nanospheres incorporating quantum dots (QD) and iron oxide nanoparticles (IONP) were prepared by the conventional emulsion method. The percentage of QD and IONP incorporated in gelatin nanospheres was changed by the concentrations of gelatin and glutaraldehyde used. However, the apparent size and surface zeta potential were hardly changed. Gelatin nanospheres incorporating QD and IONP were treated with octa-arginine (R8) of a cell-penetrating peptide. When incubated with normal human articular chondrocytes, gelatin nanospheres incorporating QD and IONP were efficiently internalized into the cells although their cytotoxicity was observed at the R8 concentration of 320 μM. The cells internalizing gelatin nanospheres incorporating QD and IONP could be visualized by both the optical and MR imaging modalities. It is concluded that gelatin nanospheres incorporating QD and IONP are promising for the probe of multimodal cell imaging.

SPECT-computed tomography in rats with TNBS-induced colitis: A first step toward functional imaging

AIM

To assess the feasibility of SPECT-computed tomography (CT) in rats with trinitrobenzene sulfonic acid (TNBS)-induced acute colitis and confront it with model inflammatory characteristics.

METHODS

Colitis was induced in Sprague-Dawley rats by intrarectal injection of TNBS (n = 10) while controls received vehicle (n = 10). SPECT-CT with intravenous injection of 10 MBq of 67Ga-Citrate was performed at day 2. SPECT-CT criteria were colon wall thickness and maximal wall signal intensity. Laboratory parameters were assessed: colon weight:length ratio, colon cyclooxygenase-2 expression by western blot and histological inflammatory score.

RESULTS

Colon weight/length ratio, colon COX-2 expression and histological inflammatory score were significantly higher in the TNBS group than in the control group (P = 0.0296, P < 0.0001, P = 0.0007 respectively). Pixel max tend to be higher in the TNBS group than in the control group but did not reach statistical significance (P = 0.0662). Maximal thickness is significantly increased in the TNBS group compared to the control group (P = 0.0016) while colon diameter is not (P = 0.1904). Maximal thickness and colon diameter were correlated to colon COX-2 expression (P = 0.0093, P = 0.009 respectively) while pixel max was not (P = 0.22). Maximal thickness was significantly increased when inflammation was histologically observed (P = 0.0043) while pixel max and colon diameter did not (P = 0.2452, P = 0.3541, respectively).

CONCLUSION

SPECT-CT is feasible and easily distinguished control from colitic rats.

Molecular Imaging in Preclinical Models of IBD with Nuclear Imaging Techniques: State-of-the-Art and Perspectives

Inflammatory bowel disease (IBD), which includes ulcerative colitis and Crohn's disease, is characterized by chronic unregulated inflammation of the intestinal mucosa of the gastrointestinal tract. To date, this pathology has no cure. Colonoscopy and biopsies are the current gold standard diagnostic tools. However, being a chronic disease, IBD requires continuous follow-up to check for disease progress, treatment response, and remission. Unfortunately, these 2 diagnostic procedures are invasive and generally unable to show the cellular and molecular changes that take place in vivo. In this context, it is clear that there is a strong need for optimized noninvasive imaging techniques able to overcome the aforementioned limitations. This review aims to bring to light the scientific advancements that have been achieved so far in nuclear medicine in relation to tracking of immune cells involved in the preclinical models of IBD. In particular, this review will explore the advantages and limitations of the radiopharmaceuticals that aim to track whole cells like neutrophils, those that involve the radiolabeling of immune cell substrates or available human IBD medical therapies, and those that aim to track cell signaling molecules (e.g., cytokines and cell adhesion molecules). After a detailed critical summary of the state-of-the art, the challenges and perspectives of molecular imaging applied to IBD studies will be analyzed. Special attention will be paid to the translational potential of the described techniques and on the potential impact of these innovative approaches on the drug discovery pipelines and their contribution to the evolution of personalized medicine.

Reporter gene technologies for imaging cell fates in hematopoiesis

Advances in noninvasive imaging technologies that allow for in vivo dynamic monitoring of cells and cellular function in living research subjects have revealed new insights into cell biology in the context of intact organs and their native environment. In the field of hematopoiesis and stem cell research, studies of cell trafficking involved in injury repair and hematopoietic engraftment have made great progress using these new tools. Stem cells present unique challenges for imaging since after transplantation, they proliferate dramatically and differentiate. Therefore, the imaging modality used needs to have a large dynamic range, and the genetic regulatory elements used need to be stably expressed during differentiation. Multiple imaging technologies using different modalities are available, and each varies in sensitivity, ease of data acquisition, signal to noise ratios (SNR), substrate availability, and other parameters that affect utility for monitoring cell fates and function. For a given application, there may be several different approaches that can be used. For mouse models, clinically validated technologies such as magnetic resonance imaging (MRI) and positron emission tomography (PET) have been joined by optical imaging techniques such as in vivo bioluminescence imaging (BLI) and fluorescence imaging (FLI), and all have been used to monitor bone marrow and stem cells after transplantation into mice. Photoacoustic imaging that utilizes the sound created by the thermal expansion of absorbed light to generate an image best represents hybrid technologies. Each modality requires that the cells of interest be marked with a genetic reporter that acts as a label making them uniquely visible using that technology. For each modality, there are several labels to choose from. Multiple methods for applying these different labels are available. This chapter provides an overview of the imaging technologies and commonly used labels for each, as well as detailed protocols for gene delivery into hematopoietic cells for the purposes of applying these specific labels to cell trafficking. The goal of this chapter is to provide adequate background information to allow the design and implementation of an experimental system for in vivo imaging in mice.

Brain ingress of regulatory T cells in a murine model of HIV-1 encephalitis

CD4+CD25+ regulatory T cells (Treg) transform the HIV-1 infected macrophage from a neurotoxic to a neuroprotective phenotype. This was demonstrated previously in a murine model of HIV-1 encephalitis induced by intracranial injection of HIV-1/vesicular stomatitis virus-infected bone marrow macrophages. In this report, relationships between Treg ingress of end organ tissues, notably the brain, and neuroprotection were investigated. Treg from EGFP-transgenic donor mice were expanded, labeled with indium-111, and adoptively transferred. Treg distribution was assayed by single photon emission computed tomography and immunohistochemistry. Treg readily migrated across the blood brain barrier and were retained within virus-induced neuroinflammatory sites. In non-inflamed peripheral tissues (liver and spleen) Treg were depleted. These observations demonstrate that Treg migrate to sites of inflammation where they modulate immune responses.

An Ultrahigh Resolution SPECT System for I-125 Mouse Brain Imaging Studies

This paper presents some initial experimental results obtained with a dual-head prototype single photon emission microscope system (SPEM) that is dedicated to mouse brain studies using I-125 labeled radiotracers. In particular, this system will be used for in vivo tacking of radiolabeled T cells in mouse brain. This system is based on the use of the intensified electron multiplying charge-coupled device (I-EMCCD) camera that offers the combination of an excellent intrinsic spatial resolution, a good signal-to-noise ratio, a large active area and a reasonable detection efficiency over an energy range between 27-140keV. In this study, the dual-head SPEM system was evaluated using both resolution phantoms and a mouse with locally injected T cells labelled with I-125. It was demonstrated that for a relatively concentrated source object, the current dual-head SPEM system is capable of visualizing the tiny amount of radioactivity (~12 nCi) carried by a very small number (<1000) of T cells. The current SPEM system design allows four or six camera heads to be installed in a stationary system configuration that offers a doubled or tripled sensitivity at a spatial resolution similar to that obtained with the dualhead system. This development would provide a powerful tool for in vivo and non-invasive tracking of radiolabeled T cells in mouse brain and potentially for other rodent brain imaging studies.

Glutathione peroxidase 2 and aquaporin 8 as new markers for colonic inflammation in experimental colitis and inflammatory bowel diseases: an important role for H2O2?

OBJECTIVE

Different mouse models of inflammatory bowel diseases (IBD) demonstrate various aspects of the pathophysiology of IBD. We looked for overlapping gene expression profiles in three different mouse models of experimental colitis and analysed whether these overlapping genes are of help to find new genes that could be used as general markers in human IBD.

METHODS

Using Agilent mouse TOX oligonucleotide microarrays, we analysed the gene expression profiles in three widely used models of experimental colitis: 2,4,6-trinitrobenzene sulphonic acid, dextran sodium sulfate and CD4CD45RB transfer and looked for overlapping gene expression in these models. Overlapping genes were analysed using Lightcycler (Roche Diagnostics, Mannheim, Germany) in biopsy materials from human IBD and control tissue.

RESULTS

Compared with control mice in dextran sodium sulfate, 2,4,6-trinitrobenzene sulphonic acid and the CD45RB transfer colitis mice five known genes, extracellular proteinase inhibitor (Expi), glutathione peroxidase 2 (Gpx2), mast cell protease 1 (Mcpt1), resistin-like beta (Retnlb) and sulphatase 2 (Sulf2), and two unknown genes were upregulated and the two genes aquaporin 8 (Aqp8) and kallikrein 5 (Klk5) were downregulated in all three models. In human Crohn's disease and ulcerative colitis biopsies, one of the upregulated glutathione peroxidase (Gpx2) and one of the downregulated Aqp8 genes in the mouse models were also differentially expressed in affected colonic tissue of patients with IBD.

CONCLUSION

Experimental mouse models are suitable models for the search of new markers for human IBD. As both Gpx2 and Aqp8 are involved in H2O2 metabolism (Gpx2 as a radical scavenger whereas Aqp8 facilitates its diffusion), upregulation of Gpx2 and downregulation of Aqp8 could be a mechanism to defend against severe oxidative stress and indicate that H2O2 is a universal mediator in the inflammatory process in the colon. This provides a focus on homeostasis of the antioxidant pathway and its importance in IBD.

Molecular pathology of malignant gliomas

Malignant gliomas, the most common type of primary brain tumor, are a spectrum of tumors of varying differentiation and malignancy grades. These tumors may arise from neural stem cells and appear to contain tumor stem cells. Early genetic events differ between astrocytic and oligodendroglial tumors, but all tumors have an initially invasive phenotype, which complicates therapy. Progression-associated genetic alterations are common to different tumor types, targeting growth-promoting and cell cycle control pathways and resulting in focal hypoxia, necrosis, and angiogenesis. Knowledge of malignant glioma genetics has already impacted clinical management of these tumors, and researchers hope that further knowledge of the molecular pathology of malignant gliomas will result in novel therapies.

In vivo imaging of mucosal CD4+ T cells using single photon emission computed tomography in a murine model of colitis

Immune responses that occur in the context of human infectious and inflammatory diseases are usually studied by sampling cells from peripheral blood, from biopsies, or by end-point harvests at necropsy. These approaches are likely to yield information that is incomplete and/or non-representative. Here, we report the development and validation of a non-invasive method to localize and to quantitate the disposition of specific subpopulations of cells in vivo. In a murine model of dextran sulfate sodium (DSS)-induced colitis, CD4+ T cells were visualized in the colon by single photon emission computed tomography (SPECT-CT) after injection of monoclonal, non-depleting, indium-111 (111In) labeled anti-CD4+ antibodies. The SPECT-CT colon uptake ratio (CUR) was found to correlate (p<0.01) with the number of total CD4+ T cells and with standard measures of pathology (colon length, cell counts, and histopathologic evidence of apoptosis, edema, and cellular infiltrates) as assessed by direct examination of diseased colon. Each of these parameters, including the SPECT-CT signal uptake, increased as a function of DSS dose (p<0.05). We conclude that CT-SPECT imaging using an 111In-labeled anti-CD4+ antibody is reflective of traditional parameters of pathology in this experimental model of murine colitis. This approach should be readily applicable to the imaging of discrete cell subpopulations in non-human primates and in humans, thus augmenting our understanding of infectious diseases and inflammation in vivo.

Comparative analysis of colonic gene expression of three experimental colitis models mimicking inflammatory bowel disease

BACKGROUND

Mouse models of inflammatory bowel diseases (IBD) are used to unravel the pathophysiology of IBD and to study new treatment modalities, but their relationship to Crohn's disease (CD) or ulcerative colitis (UC) is speculative.

METHODS

Using Agilent mouse TOX oligonucleotide microarrays, we analyzed colonic gene expression profiles in three widely used models of experimental colitis. In 2 of the models (TNBS and DSS-induced colitis), exogenous agents induce the colitis. In the third model the colitis is induced after transfer of a T-cell population (CD4(+)CD45RB(high) T cells) that lacks regulatory cells into an immunodeficient host.

RESULTS

Compared with control mice, in DSS, TNBS, and the CD45RB transfer colitis mice, 387, 21, and 582 genes were more than 2-fold upregulated in the intestinal mucosa. Analyses of exclusively shared gene expression profiles between the different models revealed that DSS/transfer colitis share 69 concordantly upregulated genes, DSS/TNBS 6, and TNBS/transfer colitis 1. Seven genes were upregulated in all three models. The CD45RB transfer model expression profile included the most genes that are known to be upregulated in IBD. Of 32 genes that are known to change transcriptional activity in IBD (TNF, IFN-gamma, Ltbeta, IL-6, IL-16, IL-18R1, IL-22, CCR2, 7, CCL2, 3, 4, 5, 7, 11, 17, 20, CXCR3, CXCL1, 5, 10, Mmp3, 7,9, 14, Timp1, Reg3gamma, and Pap, S-100a8, S-100a9, Abcb1, and Ptgs2), 2/32 are upregulated in TNBS, 15/32 are upregulated or downregulated in DSS and 30/32 are upregulated or downregulated in the CD45RB transfer colitis.

CONCLUSION

The pattern of gene expression in the CD45RB transfer model most closely reflects altered gene expression in IBD.

Methods for Imaging Cell Fates in Hematopoiesis

Modern imaging technologies that allow for in vivo monitoring of cells in intact research subjects have opened up broad new areas of investigation. In the field of hematopoiesis and stem cell research, studies of cell trafficking involved in injury repair and hematopoietic engraftment have made great progress using these new tools. Multiple imaging modalities are available, each with its own advantages and disadvantages, depending on the specific application. For mouse models, clinically validated technologies such as magnetic resonance imaging (MRI) and positron emission tomography (PET) have been joined by optical imaging techniques such as in vivo bioluminescence imaging (BLI) and fluorescence imaging, and all have been used to monitor bone marrow and stem cells after transplantation into mice. Each modality requires that the cells of interest be marked with a distinct label that makes them uniquely visible using that technology. For each modality, there are several labels to choose from. Finally, multiple methods for applying these different labels are available. This chapter provides an overview of the imaging technologies and commonly used labels for each, as well as detailed protocols for gene delivery into hematopoietic cells for the purposes of applying these labels. The goal of this chapter is to provide adequate background information to allow the design and implementation of an experimental system for in vivo imaging in mice.

Quantitative magnetic resonance and SPECT imaging for macrophage tissue migration and nanoformulated drug delivery

We posit that the same mononuclear phagocytes (MP) [bone marrow (BM) and blood monocytes, tissue macrophages, microglia, and dendritic cells] which serve as targets, reservoirs, and vehicles for HIV dissemination, can be used as vehicles for antiretroviral therapy (ART). Toward this end, BM macrophages (BMM) were used as carriers for nanoparticle-formulated indinavir (NP-IDV), and the cell distribution was monitored by single photon emission computed tomography (SPECT), transverse relation time (T2)* weighted magnetic resonance imaging (MRI), histology, and gamma-scintillation spectrometry. BMM labeled with super paramagnetic iron oxide and/or 111indium oxine were infused i.v. into naïve mice. During the first 7 h, greater than 86% of cell label was recorded within the lungs. On Days 1, 3, 5, and 7, less than 10% of BMM were in lungs, and 74-81% and 13-18% were in liver and spleen, respectively. On a tissue volume basis, as determined by SPECT and MRI, BMM densities in spleen and liver were significantly greater than other tissues. Migration into the lymph nodes on Days 1 and 7 accounted for 1.5-2% of the total BMM. Adoptive transfer of BMM loaded with NP-IDV produced drug levels in lymphoid and nonlymphoid tissues that exceeded reported therapeutic concentrations by 200- to 350-fold on Day 1 and remained in excess of 100- to 300-fold on Day 14. These data show real-time kinetics and destinations of macrophage trafficking and demonstrate the feasibility of monitoring macrophage-based, nanoformulated ART.

Magnetic resonance imaging of experimental mouse colitis and association with inflammatory activity

BACKGROUND

Ulcerative colitis and Crohn's disease are the major chronic inflammatory bowel diseases affecting the gastrointestinal tract in humans. Imaging techniques such as endoscopy and computed tomography are used to monitor disease activity. Magnetic resonance imaging (MRI) is emerging as a diagnostic modality, and studies have shown that MRI can be used in the diagnostic procedure of patients with inflammatory bowel disease. The aim of the present study was to investigate the role of MRI in quantitatively reflecting inflammation in an experimental mouse colitis model.

METHODS

Colonic inflammation was induced by exposing mice to dextran sulfate sodium. MRI was used to assess colon wall thickness, T2-weighted (T2w) signal, and contrast-enhanced T1-weighted (T1w) signal in inflamed and healthy animals in vivo. Haptoglobin and interleukin-1beta served as systemic and local inflammatory markers, and macroscopic ex vivo scoring of the colon was performed to assess colonic inflammation.

RESULTS

Dextran sulfate sodium-exposed animals displayed increased levels of inflammatory markers and higher inflammatory score compared with healthy animals. Colon wall thickness and contrast-enhanced T1w signal were significantly increased in dextran sulfate sodium-exposed compared with healthy animals. In addition, the T2w signal was positively correlated with haptoglobin levels and colon wall thickness in the inflamed animals.

CONCLUSIONS

Our results show that MRI can be used to depict healthy and inflamed mouse colon and that the T2w signal, contrast-enhanced T1w signal, and colon wall thickness may be used to characterize inflammation in experimental colitis. These potential biomarkers may be useful in the evaluation of putative drugs in longitudinal studies in both mice and humans.