Asma Al-Jasser

By K.A. Al-Anazi and A.M. Al-Jasser

Mesenchymal stem cells (MSCs) are heterogeneous progenitor cells that have the capacity of self-renewal and multi-lineage differentiation. These adult stem cells can be derived from several sources including bone marrow (BM), peripheral blood, cord blood, placenta, amniotic fluid, skin and adipose tissue. They have certain distinguishing features and their immunomodulatory and immunosuppressive properties enable them to have several therapeutic and clinical applications. Recently, MSCs have gained enormous potential as they can potentially cure various intractable and chronic diseases and as they have shown effectiveness in the treatment of various infections in animal models and in early clinical trials. MSCs are essential constituents of the framework that supports organ integrity and tissue barriers. Suppression of both T and B cells allows them to be major players in the innate response to bacterial infection and in controlling inflammatory response. Human BM-MSCs possess direct antibacterial activity against Gram-negative bacilli and they have been shown to improve survival and reduce mortality in animal models having septic complications. BM-MSCs are effective in treating sepsis and acute respiratory distress syndrome in high-risk patients such as those with malignant hematological disorders, recipients of solid organ and hematopoietic stem cell transplantation (HSCT) and patients receiving advanced level of care in intensive care units. Additionally, human BM-MSCs can act as drug delivery vehicles by enhancing the effectiveness of conventional antimicrobials and thus they may prevent the evolution of drug-resistant microbes. MSCs contain a subset of interleukin-17+ that is capable of inhibiting the growth of Candida albicans (C. albicans). Also, CD 271+ BM-MSCs may provide a long-term protective intracellular niche in the host where Mycobacterium tuberculosis (M.TB) organisms remain viable but in a dormant state. Two recent clinical trials in humans that included 57 patients have shown that autologous transplantation of MSCs can successfully treat multidrug resistant (MDR) strains of M.TB. Animal studies have demonstrated that MSCs enhance host defenses against malaria. MSC therapy improves liver function and promotes hepatocellular regeneration in patients with hepatic fibrosis caused by schistosomiasis. Transplantation of MSCs has been shown to reverse right ventricular dilatation, cardiomyopathy and advanced cardiac involvement caused by Trypanosoma cruzi infection.

Part of the book: Progress in Stem Cell Transplantation

By Khalid Ahmed Al-Anazi, Waleed K. Al-Anazi and Asma M. Al-Jasser

Mesenchymal stem cells are heterogenous adult multipotent stromal cells that can be isolated from various sources including: bone marrow, peripheral blood, umbilical cord blood, dental pulp, and adipose tissue. They have certain immunomodulatory, immunosuppressive, and antimicrobial properties that enable them to have several therapeutic and clinical applications including: treatment of autoimmune disorders, role in hematopoietic stem cell transplantation and regenerative medicine, as well as treatment of various infections and their associated complications such as septic shock and acute respiratory distress syndrome. Although more success has been achieved in preclinical trials on the use of mesenchymal stem cells in animal models than in human clinical trials, particularly in septic shock and Chagas disease, more progress has been made in both disorders after the recent use of specific sources and certain doses of mesenchymal stem cells. Nevertheless, the utilization of this type of stem cells has shown remarkable progress in the treatment of few infections such as tuberculosis. The clinical application of mesenchymal stem cells in the treatment of several diseases still faces real challenges that need to be resolved. The following book chapter will be an updated review on the role of mesenchymal stem cells in various infections and their complications.

Part of the book: Update on Mesenchymal and Induced Pluripotent Stem Cells