Influence of organ donor attributes and preparation characteristics on the dynamics of insulin secretion in isolated human islets

Abstract

In vitro studies of human pancreatic islets are critical for understanding normal insulin secretion and its perturbations in diabetic β‐cells, but the influence of islet preparation characteristics and organ donor attributes in such experiments is poorly documented. Preparations from normal donors were tested with a standardized protocol evaluating dynamic insulin secretion induced by glucose, tolbutamide, and cAMP (forskolin). Secretion rates, normalized to insulin content (fractional insulin secretion), were analyzed as a function of preparation and donor characteristics. Low purity (25–45%) of the preparation (n = 8) blunted the first phase of insulin secretion induced by glucose or tolbutamide and increased basal secretion, resulting in threefold lower stimulation index than in more pure (55–95%) preparations (n = 43). In these more pure preparations, cold ischemia time (1–13 h) before pancreas digestion did not impact insulin secretion. Islet size (estimated by the islet size index) did not influence the dynamics of secretion, but fractional insulin secretion rates were greater in large than small islets, and positively correlated with islet size. Age of the donors (20–68 years) had no influence on islet size and insulin content or on dynamics and amplitude of insulin secretion, which were also similar in islets from male and female donors. In contrast, islet size and islet insulin content (normalized for size), and basal or stimulated insulin secretion positively correlated with Body‐Mass Index (19–33). These results contradict previous reports on the impact of donor age and islet size and point to possible confounding effects of donor BMI in insulin secretion studies with isolated human islets.

Use of human islets to understand islet biology and diabetes: progress, challenges and suggestions

“…This discussion about the criteria for islet quality only applies to human islets used for research; clinical islet transplantation programmes have developed quality metrics for human islets used for clinical transplantation [12]. Three recent reports have assessed the in vitro islet insulin secretory function of a large number (>50) of human islet preparations by perifusion or static culture [9,13,14]. Two reports described human islet preparations generated at one or two islet isolation sites (the University of Alberta or the University of Louvain and the University of Lille) [9,13], and the third report described preparations from multiple IIDP-sponsored isolation centres [14].…”

“…Three recent reports have assessed the in vitro islet insulin secretory function of a large number (>50) of human islet preparations by perifusion or static culture [9,13,14]. Two reports described human islet preparations generated at one or two islet isolation sites (the University of Alberta or the University of Louvain and the University of Lille) [9,13], and the third report described preparations from multiple IIDP-sponsored isolation centres [14]. These studies used different methodologies to examine the determinants of human islet functional variability.…”

“…These studies used different methodologies to examine the determinants of human islet functional variability. Nonetheless, they represent a strong foundation to address sources of human islet functional inconsistency that may arise from variation in donor characteristics, pancreas processing and/or isolation centres [9,13,14].…”

A Call for Improved Reporting of Human Islet Characteristics in Research Articles

“…These include differences in donor characteristics (age, sex, ethnic background, health status prior to death, and cause of death); differences in pancreas procurement (isolation center, islet handling, estimated purity, and viability); warm and cold ischemia times; and tissue culture (1). All of these factors influence, to varying degrees, the morphology and function of the islets as investigated in the laboratory (2)(3)(4)(5). For example, out of the 13 islet preparations from donors without diabetes for which islet cell composition is provided in the Human Pancreas Analysis Program PancDB database of the Human Islet Research Network (6), the relative proportion of islet b-cells ranged from 28.5% to 75.8% of the total endocrine cell population (e.g., a-, b-, d-, and e-cells).…”

A call for improved reporting of human islet characteristics in research articles

“…These include differences in donor characteristics (age, sex, ethnic background, health status prior to death and cause of death); differences in pancreas procurement (isolation centre, islet handling, estimated purity and viability); warm and cold ischaemia times; and tissue culture [1]. All of these factors influence, to varying degrees, the morphology and function of the islets as investigated in the laboratory [2][3][4][5]. For example, out of the 13 islet preparations from donors without diabetes for which islet cell composition is provided in the Human Pancreas Analysis Program PancDB database of the Human Islet Research Network [6], the relative proportion of islet beta cells ranged from 28.5% to 75.8% of the total endocrine cell population (e.g.…”