Targeting Apoptosis and Necroptosis Inhibition to Improve Islet Graft Function

• Author / Creator

  Aggarwal, Saloni

• Islet cell transplantation is an effective method to treat type 1 diabetes mellitus, however, significant barriers currently exist preventing its implementation as the gold standard therapy. Of note, cell death in the acute post-transplant period accounts for loss of up to 80% of newly transplanted islets. Cell death can be mediated in multiple different ways, and the two primary forms of cell death are apoptosis and necrosis. Significant efforts have been applied in preventing apoptosis following islet transplantation, however, concurrent inhibition of both pathways simultaneously is a relatively new approach. In this thesis, we investigated the effect of apoptosis and regulated necrosis inhibition on β-cell survival and function, both in vivo and in vitro. MIN6 cells, derived from an immortalized mouse insulinoma, were cultured with and without apoptosis (ZVAD-FMK) and regulated necrosis inhibitors (Necrostatin 1, Necrostatin 1s) for 24-72 hours, and under basal and stressed conditions. Cell vitality, glucose stimulated insulin secretion, and oxygen consumption rates were measured and analyzed. This revealed statistically significant differences between treated and untreated cells, suggesting the therapeutic potential of treating islets with apoptosis and regulated necrosis inhibitors prior to islet transplantation.

  Next, human islets were treated for 24h with apoptosis and regulated necrosis inhibitors, and marginal mass transplantation of these islets under the kidney capsule of diabetic mice was performed. Mice were followed for 60 days, and improved reversal of diabetes and maintenance of glycemic control was observed in mice treated with the inhibitors in combination and alone. This indicates that pre-treatment of islets with apoptosis and regulated necrosis inhibitors prior to transplantation may reduce cell death following transplantation, and potentially improve islet engraftment. This is of great clinical relevance, as targeting regulated cell death effectively may in the future lead to improved single donor success rates, reduced islet mass required in each transplant, and long-term insulin independence following the procedure.

• Subjects / Keywords

  • Islet Transplantation
  • Type 1 Diabetes Mellitus
  • Cell Death
  • Necroptosis

• Graduation date

  Fall 2022

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-0v74-rb12

• License

  This thesis is made available by the University of Alberta Library 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.