Inflammatory bowel diseases: current therapeutic approaches and potential of using stem cells

Inflammatory bowel diseases (IBDs) are chronic and progressively deteriorating in nature without many promising curative treatments. Chronic inflammation of not well defined origins is considered to be the root cause of the problem which affects intestinal mucosa with or without transmural involvement. IBDs are divided in two main categories: Crohn's disease (CD) and ulcerative colitis (UC). While there is no long lasting cure for IBDs, current therapies can only reduce the causative inflammatory process with the hope to induce long-term remission. Treatment modalities for the IBDs are still evolving. The increased understanding of the underlying immunopathology has helped identify new targeted treatment options like immunosuppressive antibodies directed against signaling molecules. Use of stem cells, which are capable of modulating the immune system, can offer a long lasting relief to the patients suffering from the disease. The goal for stem cell-based therapy is to achieve long lasting cure, if not a permanent one. To achieve this, it would be desirable to obtain cell types, whether genetically modified or naturally occurring, having a high migratory ability in addition to homing ability into the afflicted parts of intestine. These cells should also have high in vivosurvival potential, and then be able to regulate the immune reaction without provoking any response from the host’s immune system and repair the injured tissue. Hematopoietic stem cells (HSC) and mesenchymal stromal cells (MSC) therapies are being investigated as a treatment for IBDs. MSC therapy is well tolerated and has minimal established side-effects compared to HSC therapy, which involves ablative chemotherapy. Several clinical studies using MSCs have been initiated and some early results suggest several inherent problems. In each study, optimization of MSC therapy appears to be the most urgent problem, which can be resolved only by scientifically unveiling the mechanisms of therapeutic action of stem cells. In this review, we summarize current therapies for IBDs and recent advances in the field of stem cell therapy, which offer promise to become the next generation treatment of choice.