Hi there. So in this lecture, we will focus on novel treatment options for the transplant recipient. Namely cellular therapy. These include various cells. Including mesenchymal stromal cells, also called MSCs, and regulatory T cells. Since these cells are immunosuppressive and might have less side effects compared to the current therapy, they are of interest in transplantation. So in this lecture we have chosen to focus on MSCs. In the lecture of tolerance you will get to know more about the regulatory T cells. We will answer the following questions. What are MSCs? Why are they of interest in the transplant field? And which steps are performed from isolation to infusion? And what are the indications, initial results and lessons learned so far? So, after this movie, you will be able to answer these questions. MSCs of interest in various clinical protocols in transplantation, with the aim to induce tolerance, to prolong allograft survival, to inhibit and treat rejection, and to minimize fibrosis. Moreover, they can be used in protocols with minimization of the other toxic medications. First clinical studies are now starting to test these indications, after safety and feasibility has been tested. So let's now look at the movie, the whole process from isolation through infusion and follow up will be described. MSCs are an interesting candidate in the transplant recipient due to their immune suppressive and reparative properties. MSCs can be isolated from the bone marrow from the iliac crest through bone marrow aspiration. The bone marrow contains mainly hematopoietic cells which have been used to treat severe diseases of the bone marrow, including leukemia. These cells have also been used in clinical protocols after transplantation with the aim to induce tolerance of the transplanted organ. The bone marrow also contains a small fraction of primary MSCs, making the amplification of MSCs ex vivo necessary. Criteria that identify MSCs are, their adherence to plastic in standard culture conditions. Their differentiation capacity in cartilage, adipose tissue, and bone and their phenotype. Besides the bone marrow, MSCs can easily be isolated from fat tissue. In addition, they can be isolated from virtually all organs, including the kidney, which is of interest for renal repair. Why are MSCs of interest after transplantation? MSC's have important effects on various players of the innate and adaptive immune system. Including macrophages, DC's, T-cells and B-cells, via the production of immune modulating factors including IDO, PGE2, IL-10 and HLA-G. MSCs also inhibit fibrosis by releasing various vectors including HGF and BMP-7. MSCs have direct effects on the endothelium by enhancing angiogenesis via various angiogenic factors including VEGF and angiopoeitins. All these effects by MSCs could be of major importance for repair of the transplanted kidney. The amplification of MSCs should be performed under strict good manufacturing practice conditions. After the isolation, MSCs are cultured and expended through different steps. First, mononuclear cells are isolated from the bone marrow using density gradient separation. Then the mononuclear cells are cultured using an optimal combination of growth factors and cytokines. Through plastic adherence, MSCs are selected. To obtain enough cells, the culture and expansion process will take about four weeks. Before MSCs are released, several quality tests are performed, which include service marker expression, absence of microbial contamination. Spindle shaped morphology, colorless cell suspension devoid of cell aggregates. No genetic abnormalities, and viability. Awaiting the results of the quality tests, and to make infusion of MSC a later time point possible, MCSs are frozen. To maintain cell viability control rate freezing is used with a guided temperature profile. After this controlled procedure, MSCs are stored in vapor phase nitrogen until their use. The source can be autologous from the patient itself, or allogeneic from a third party donor or from the kidney donor. Most protocols in renal transplantation use autologous MSCs. Allogeneic MSCs are also of interest, since these cells can be taken off the shelf at any moment. However, these cells from another donor might induce immunization of the patient. Therefore, HLA selection criteria are advised. MSCs are infused in a patient via intravenous infusion. Follow up studies during the outpatient clinics include determination of safety and feasibility, lab and urinary markers for renal function, histology, immune monitoring, and measurement of biomarkers. Of importance follow up should not only be performed in the short term, but also on the long term. So are you able to explain the different steps of MSC isolation to treatment after seeing this movie? Let's look at the important lessons. So first of all, MSCs are of interest for transplantation due to immunosuppressive and reparative properties. Second, the process from isolation through administration is complex. And third indications include treatment of rejection, induction of tolerance and prevention of fibrosis. And fourth, close follow up of the treated patients is of major importance. There are still many questions which should be investigated the coming years regarding cell therapy. There is optional literature on this subject so I invite to discuss the challenges online. What do you think are the major challenges and can you come up with solutions? In the fourth module in the interview with Professor Wood about tolerance, you will learn more about the regulatory T cells. Years of research in her lab have now led to one of the first clinical trials of regulatory T cells into human transplantation.