Animal models for the study of inflammatory bowel diseases. a meta-analysis on modalities for imaging inflammatory lesions

Inflammatory bowel diseases are lifelong disorders affecting the gastrointestinal tract characterized by intermittent disease flares and periods of remission with a progressive and destructive nature. Unfortunately, the exact etiology is still not completely known, therefore a causal therapy to cure the disease is not yet available. Current treatment options mainly encompass the use of non-specific anti-inflammatory agents and immunosuppressive drugs that cause significant side effects that often have a negative impact on patients' quality of life. As the majority of patients need a long-term follow-up it would be ideal to rely on a non-invasive technique with good compliance. Currently, the gold standard diagnostic tools for managing IBD are represented by invasive procedures such as colonoscopy and histopathology. Nevertheless, recent advances in imaging technology continue to improve the ability of imaging techniques to non-invasively monitor disease activity and treatment response in preclinical models of IBD. Novel and emerging imaging techniques not only allow direct visualization of intestinal inflammation, but also enable molecular imaging and targeting of specific alterations of the inflamed murine mucosa. Furthermore, molecular imaging advances allow us to increase our knowledge on the critical biological pathways involved in disease progression by characterizing in vivo processes at a cellular and molecular level and enabling significant improvements in the understanding of the etiology of IBD. This review presents a critical and updated overview on the imaging advances in animal models of IBD. Our aim is to highlight the potential beneficial impact and the range of applications that imaging techniques could offer for the improvement of the clinical monitoring and management of IBD patients: diagnosis, staging, determination of therapeutic targets, monitoring therapy and evaluation of the prognosis, personalized therapeutic approaches.