Human research islet cell culture outcomes at the Alberta Diabetes Institute IsletCore

Abstract

Human islets from deceased organ donors have made important contributions to our understanding of pancreatic endocrine function and continue to be an important resource for research studies aimed at understanding, treating, and preventing diabetes. Understanding the impacts of isolation and culture upon the yield of human islets for research is important for planning research studies and islet distribution to distant laboratories. Here, we examine islet isolation and cell culture outcomes at the Alberta Diabetes Institute (ADI) IsletCore (n = 197). Research-focused isolations typically have a lower yield of islet equivalents (IEQ), with a median of 252,876 IEQ, but a higher purity (median 85%) than clinically focused isolations before culture. The median recovery of IEQs after culture was 75%, suggesting some loss. This was associated with a shift toward smaller islet particles, indicating possible islet fragmentation, and occurred within 24 h with no further loss after longer periods of culture (up to 136 h). No overall change in stimulation index as a measure of islet function was seen with culture time. These findings were replicated in a representative cohort of clinical islet preparations from the Clinical Islet Transplant Program at the University of Alberta. Thus, loss of islets occurs within 24 h of isolation, and there is no further impact of extended culture prior to islet distribution for research.

Keywords: Human; biobanking; cell culture; insulin; islet; secretion.

Graphical abstract

Figure 1.

Post-culture loss of islets at the alberta diabetes institute IsletCore. Comparison of pre- and post-culture total islet equivalents (IEQ) (A), islet particle number (IPN) (B), insulin content (C), and DNA content (D) in preparations from the alberta diabetes institute IsletCore. Data shows median and interquartile ranges.

Figure 2.

Loss of larger islets and gain of smaller islets post-culture. Comparison from pre- to post-culture of islet particle index (IPI) (A) and the relative proportions of islet diameter categories (B) from the alberta diabetes institute IsletCore. Data show median and interquartile ranges.

Figure 3.

Islet loss occurs within 24 h, and then is unchanged for greater than 72 h. Relationship between culture time with recovery of islet equivalents (IEQs) post-culture and stimulation index (SI) of islet preparations from the alberta diabetes institute IsletCore (A,B) and in a replication cohort from the university of alberta clinical islet transplant program (C,D). The post-hoc within pairs testing p-value shown is from Wilcox rank sum adjusted with Bonferroni correction. Median and interquartile range are shown.