Objective
The central goal of this project is to determine whether supplementing isolated pancreatic islets with healthy mitochondria can preserve their viability and insulin-secreting ability before transplantation. Specifically, we aim to:
1. Establish the feasibility of introducing mitochondria derived iPSCs into mouse islets, identify the optimal dose, and confirm whether these mitochondria integrate functionally or exert transient metabolic support.
2. Apply the optimized conditions to human donor islets, assessing whether mitochondrial co-culture maintains glucose-stimulated insulin secretion (GSIS), reduces apoptosis, and sustains mitochondrial energy output.
Together, these objectives will yield the first controlled dataset defining how exogenous mitochondria affect islet health and function, a critical prerequisite for future translational studies.
Background Rationale
During isolation and culture, islets experience hypoxia, nutrient stress and oxidative injury that trigger mitochondrial dysfunction and cell death. The resulting energy failure compromises insulin secretion and reduces graft survival after transplant. Approaches that restore mitochondrial integrity could therefore have an effect on clinical outcomes.
Mitochondrial transplantation has already shown remarkable results in other organs; in models of heart attack, liver ischemia, and lung injury, transferred mitochondria restored ATP production, reduced oxidative stress, and improved recovery. First-in-human studies in pediatric patients demonstrated safety and feasibility. However, no one has yet applied this concept to pancreatic islets, where mitochondrial failure is a well recognized issue.
Meanwhile, stem-cell-derived islets, a growing and promising field in beta cell replacement therapy, share similar problems; their mitochondria are immature and inefficient. Thus, developing a reproducible mitochondrial supplementation platform could benefit both current donor-based transplantation and next-generation cell-replacement therapies.
Description of Project
Type 1 diabetes (T1D) occurs when the immune system destroys the insulin-producing ß cells in the pancreas. While insulin therapy sustains life, it cannot match the precise glucose control of a healthy pancreas. For people with severe, unstable diabetes, islet transplantation can restore natural insulin production and dramatically improve quality of life. However, this therapy remains limited because few donor pancreases are available and, even when they are, the isolated islets rapidly lose function in the short culture period before transplantation.
This project explores a novel way to "re-energize" islets by providing them with healthy mitochondria, the tiny power plants of the cell that produce energy and regulate survival. When mitochondria fail, ß cells lose the ability to release insulin effectively. We propose supplementing donor islets with mitochondria isolated from induced pluripotent stem cells (iPSCs) to restore cellular energy metabolism, reduce oxidative stress, and prevent cell death.
In a pilot experiment, human islets were first cultured for 24 hours under standard conditions, then supplemented with mitochondria and cultured for an additional 24 hours. After 48 hours, the islets co-cultured with mitochondria maintained strong insulin secretion and cell viability, while untreated controls showed some decline.
The study will proceed in two phases. Phase 1 will use mouse islets to define the safest and most effective mitochondrial dose and to confirm integration of donor mitochondria. Phase 2 will apply the optimized protocol to discarded human pancreases, processed by the Toronto Islet Program, evaluating insulin secretion, apoptosis, oxidative stress, ATP levels, and oxygen consumption. All mitochondrial preparations will be produced in collaboration with a specialized partner lab experienced in mitochondrial isolation.
If successful, this work could improve both the quantity and quality of transplantable islets, enabling more people with T1D to benefit from transplantation. Beyond donor islets, the same approach could enhance the performance of stem-cell-derived islets, a rapidly developing field in islet cell transplantation, which also suffer from mitochondrial immaturity and stress sensitivity. Even if the results are mixed, the project will clarify how mitochondrial health shapes islet survival and point toward refined strategies such as vesicle-based mitochondrial delivery or antioxidant co-therapy.
Anticipated Outcome
We anticipate that islets co-cultured with iPSCs-derived mitochondria will show: higher cell viability, preserved GSIS and improved bioenergetics.
If confirmed, these findings would support shifting from a passive culture to an an active metabolic rescue strategy. Even if improvements are temporary, mapping the dose-response and mechanisms of mitochondrial uptake will guide optimization and combination approaches.
Relevance to T1D
This project speaks directly to the mission of Breakthrough T1D, to develop transformative therapies that restore natural insulin production. By improving survival of transplanted islets, mitochondrial supplementation could increase the number of successful transplants, reduce the need for multiple donors per patient, and enhance long-term graft function.
Additionally, the same technology could benefit the merging field of stem-cell-derived islet transplantation which still struggles with metabolic immaturity.
The knowledge gained here will help define how to strengthen these lab-grown cells before transplantation.
Ultimately, this work addresses one of the biggest obstacles to curing T1D, keeping ß cells alive, functional, and ready to respond to glucose once returned to the body.