Process parameter development for the scaled generation of stem cell-derived pancreatic endocrine cells

Metabolic switching, growth kinetics and cell yields in the scalable manufacture of stem cell-derived insulin-producing cells

BACKGROUND

Diabetes is a disease affecting over 500 million people globally due to insulin insufficiency or insensitivity. For individuals with type 1 diabetes, pancreatic islet transplantation can help regulate their blood glucose levels. However, the scarcity of cadaveric donor islets limits the number of people that could receive this therapy. To address this issue, human pluripotent stem cells offer a potentially unlimited source for generating insulin-producing cells through directed differentiation. Several protocols have been developed to make stem cell-derived insulin-producing cells. However, there is a lack of knowledge regarding the bioprocess parameters associated with these differentiation protocols and how they can be utilized to increase the cell yield.

METHODS

We investigated various bioprocess parameters and quality target product profiles that may influence the differentiation pipeline using a seven-stage protocol in a scalable manner with CellSTACKs and vertical wheel bioreactors (PBS-Minis).

RESULTS

Cells maintained > 80% viability through all stages of differentiation and appropriately expressed stage-specific markers. During the initial four stages leading up to the development of pancreatic progenitors, there was an increase in cell numbers. Following pancreatic progenitor stage, there was a gradual decrease in the percentage of proliferative cells, as determined by Ki67 positivity, and a significant loss of cells during the period of endocrine differentiation. By minimizing the occurrence of aggregate fusion, we were able to enhance cell yield during the later stages of differentiation. We suggest that glucose utilization and lactate production are cell quality attributes that should be considered during the characterization of insulin-producing cells derived from stem cells. Our findings also revealed a gradual metabolic shift from glycolysis, during the initial four stages of pancreatic progenitor formation, to oxidative phosphorylation later on during endocrine differentiation. Furthermore, the resulting insulin-producing cells exhibited a response to several secretagogues, including high glucose.

CONCLUSION

This study demonstrates process parameters such as glucose consumption and lactate production rates that may be used to facilitate the scalable manufacture of stem cell-derived insulin-producing cells.

Implanted pluripotent stem-cell-derived pancreatic endoderm cells secrete glucose-responsive C-peptide in patients with type 1 diabetes

An open-label, first-in-human phase 1/2 study is being conducted to evaluate the safety and efficacy of pancreatic endoderm cells (PECs) implanted in non-immunoprotective macroencapsulation devices for the treatment of type 1 diabetes. We report an analysis on 1 year of data from the first cohort of 15 patients from a single trial site that received subcutaneous implantation of cell products combined with an immunosuppressive regimen. Implants were well tolerated with no teratoma formation or severe graft-related adverse events. After implantation, patients had increased fasting C-peptide levels and increased glucose-responsive C-peptide levels and developed mixed meal-stimulated C-peptide secretion. There were immunosuppression-related transient increases in circulating regulatory T cells, PD1^high T cells, and IL17A⁺CD4⁺ T cells. Explanted grafts contained cells with a mature β cell phenotype that were immunoreactive for insulin, islet amyloid polypeptide, and MAFA. These data, and associated findings (Shapiro et al., 2021), are the first reported evidence of meal-regulated insulin secretion by differentiated stem cells in patients.

Process parameter development for the scaled generation of stem cell-derived pancreatic endocrine cells

Diabetes is a debilitating disease characterized by high blood glucose levels. The global prevalence of this disease has been projected to reach 700 million adults by the year 2045. Type 1 diabetes represents about 10% of the reported cases of diabetes. Although islet transplantation can be a highly effective method to treat type 1 diabetes, its widespread application is limited by the paucity of cadaveric donor islets. The use of pluripotent stem cells as an unlimited cell source to generate insulin‐producing cells for implant is a promising alternative for treating diabetes. However, to be clinically relevant, it is necessary to manufacture these stem cell‐derived cells at sufficient scales. Significant advances have been made in differentiation protocols used to generate stem cell‐derived cells capable of reversing diabetes in animal models and for testing in clinical trials. We discuss the potential of both stem cell‐derived pancreatic progenitors and more matured insulin‐producing cells to treat diabetes. We discuss the need for rigorous bioprocess parameter optimization and identify some critical process parameters and strategies that may influence the critical quality attributes of the cells with the goal of facilitating scalable manufacturing of human pluripotent stem cell‐derived pancreatic endocrine cells.