Organ transplantation is a consolidated clinical procedure that prolongs and improves the quality of life of thousands of people with terminal organ failure. In 2018, Spain registered a total of 2,241 donors (48 donors per million inhabitants). As a world leader, this high donation rate allowed a total of 5,321 solid organ transplants in our country that same year: 3,313 renal, 1,230 hepatic, 321 cardiac, 369 pulmonary, 82 pancreatic and 6 small intestine. The Spanish Model in donation and transplantation is responsible for the remarkable improvement of organ donation in Spain. This activity was initially established by the National Transplant Organization (ONT), which in 2019 celebrates its 30th anniversary. Despite the increasing number of transplants performed compared to previous years and with other countries in the world, the number of patients who are in need of a transplant increases every year and represents one of the fundamental problems in solid organ transplantation: the discrepancy between the demand and the availability of organs..

Tissue engineering represents a promising approach to the problem of organ shortage. The development of organs generated by bioengineering from three-dimensional structures of extracellular matrix could become an unlimited potential source of organs for transplantation. This innovative perspective integrates multi-thematic approaches to areas such as tissue engineering, stem cell biology and transplant immunology.

Currently, the acceptance of transplanted organs depends on the immune response of the recipient. To avoid rejection, transplanted patients receive daily immunosuppressive drugs for life, which compromises the long-term survival of the transplanted organ due to their toxicity. Despite efforts to avoid the side effects of currently available immunosuppressive agents, no alternative regimen has seriously challenged the almost universal use of these medications. This underscores the need for additional approaches to develop tolerance induction protocols. Mixed chimerism, cell therapy and nanoimmunotherapy have recently emerged as therapeutic innovations that improve the effectiveness of current treatments. The clinical and pre-clinical results of these new experimental therapies demonstrate that induction of tolerance to the transplanted organ is possible in experimental animal models and in humans. Consequently, research centering on the prevention of organ-specific immune responses provides a framework for the development of targeted therapies that promote transplant tolerance.

Fundación Ramón Areces, CEU San Pablo University, the Carlos III Health Institute (ISCIII) and the National Transplant Organization (ONT) have organized this symposium which focuses on the latest advances in the field of organ transplant research and which aims to review the progress in the generation of bio-artificial organs and new approaches to tolerance induction. The objective of the meeting is to center the attention on the next frontier that represents the transformation of such advances into a clinical reality. A key element is to promote efficient research which improves current chronic immunosuppression therapies and overcomes existing limitations in organ transplantation.

The coordinators wish to express their gratitude to the Spanish Transplant Society (SET) and the Spanish Immunology Society (SEI) for their invaluable contributions to making this meeting a success.