Translational Strategies for the Clinical Transplantation of Neonatal Porcine Islets

• Author / Creator

  Ellis, Cara E

• The development of the Edmonton protocol was an important milestone in the process of establishing islet transplantation as a cure for diabetes. However, many challenges must still be overcome, including the shortage of donor organs. To address this issue, we believe that neonatal porcine islets (NPIs) are a clinically applicable, unlimited source of cells. In order for NPIs to be translated to the clinic, we believe two important issues must be addressed. The first aim of this thesis is to develop an alternate site. The second aim of this thesis focuses on developing a clinically applicable protocol for the isolation, culture, and delivery of NPIs. For the first aim, based on the understanding of the interactions between islets and extracellular matrix proteins, a type one collagen-based matrix is developed containing chitosan, chondroitin-6-sulfate, and laminin to support NPI viability and function both in vitro and in vivo in Chapter 2. Therein, we demonstrate that such a matrix has the capacity to deliver islets to an increasingly vascularized subcutaneous site. We further developed this collagen-based matrix in Chapter 3 by altering the crosslinking concentration and observing the effects on the matrix microstructure and other outcomes, including in vivo vascularization after subcutaneous transplantation. Our results indicate that this matrix could be modified to be applicable for many cell delivery systems. Chapters 4 and 5 address the second aim of this thesis, beginning with the development of a clinically applicable and scalable protocol for the isolation and culture of NPIs. Using an automated chopper, a general caspase inhibitor, and a protease inhibitor cocktail during culture in one petri dish instead of four resulted in islets with improved insulin content, β cell mass, and glucose responsiveness both in vitro and in vivo in a murine model. This modified protocol allows for the isolation of high quality islets from more pancreases in compliance with Good Manufacturing Practice (GMP), and may be further improved by replacing all reagents with those with GMP certification. Chapter 5 describes a protocol for cold storage of whole neonatal porcine pancreases as a means to transport organs from a designated pathogen free source animal housing facility to a GMP cell manufacturing facility. Finally, in Chapter 6 we explore some of the ethical and regulatory issues that must be considered to justify xenotransplantation clinical trials in Canada. We propose that NPIs have demonstrated efficacy to justify clinical trials; the safety data gathered from these clinical trials would then be extremely valuable for Canadian citizens to decide in a deliberative democratic model whether clinical trials for other cell or tissue xenotransplantation can also be justified. We conclude that there is a clear expected benefit for xenotransplantation as an unlimited source of donor tissue, particularly in the case of islet transplantation. Collectively, these studies demonstrate that NPIs have the potential to be utilized as a clinical cell therapy for type 1 diabetes, isolated and cultured following a clinically applicable protocol and delivered in a collagen-based matrix that can be further modified as required. This matrix could also be readily retrieved if necessary. Furthermore, sharing of expertise and expenses across centers is feasible with a successful cold storage protocol, further improving the translational relevance of NPIs. In summary, this thesis advances the applicability of the NPI cell therapy as a treatment for type 1 diabetes.

• Subjects / Keywords

  • Public health policy
  • Islet transplantation
  • Tissue-engineering
  • Neonatal porcine islets
  • Xenotransplantation
  • Diabetes
  • Biomaterials

• Graduation date

  Fall 2015

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3833N41N

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.