Cell therapies for inflammatory bowel diseases.

Present therapy of inflammatory bowel diseases (IBDs) is aimed at relieving inf lammation and treating signs and symptoms. Therapy consists of nonspecific anti-inflammatory agents, such as 5-aminosalicylic acid, glucocorticoids, immunomodulators and anti-TNF therapy. The goals of therapy should include the induction and maintenance of remission and an attempt to heal the mucosa with the ultimate goal being restitution of normal intestinal function. Despite an optimized use of immunosuppressors and the new biologic agents, the need for intestinal resection in Crohn’s disease (CD) has remained stable [1]. Primary and secondary failure to respond to approved therapies and, in some cases, the inability to provide a surgical solution to a particular patient owing to the extension and/or location of the lesions, represent unmet needs in the treatment of IBD. Two streams of research, experimental and clinical, are the origins of the increasing utilization of cell therapies for severe immune-mediated diseases, including IBD. The types of cell therapies for these diseases can be divided into two different areas: stem cell therapies and selected/conditioned immune cell therapies, the latter including dendriticand Treg-based cell therapies. The considerable excitement surrounding the stem cell field was initially based on the unique biological properties of these cells and their capacity to selfrenew and regenerate tissue and organ systems. Later, the immuno modulatory ability of stem cell therapy has also become apparent. The definition of a ‘stem cell’ conventionally indicates the hemato poietic variety, with reference to the myeloid and lymphoid lineages. However, a distinct lineage is now known to consist of mesenchymal stromal cells. Similar to hematopoietic stem cells (HSCs), mesenchymal stem cells (MSCs) are rare in the bone marrow, representing one in 10,000 nucleated cells [2]. The ontogenic relationship between HSCs and MSCs remains unclear.