Islet isolation for allotransplantation: variables associated with successful islet yield and graft function

Abstract

Aims/hypothesis: Efficient islet isolation is an important prerequisite for successful clinical islet transplantation. Although progressively improved, islet yield and quality are, however, unpredictable and variable and require standardisation. Methods: Since 1989 we have processed 437 pancreases using the automated method. The donor characteristics, pancreas procurement, and digestion and purification procedures including a wide enzyme characterisation of these pancreases were analysed and correlated with islet yield and transplant outcome. Results: By univariate analysis, islet yield was significantly associated with donor age (r=0.16; p=0.0009), BMI (r=0.19; p= 0.0004), good pancreas condition (p=0.0031) and weight (r=0.15; p=0.0056), total collagenase activity (r=0.22; p= 0.0001), adjusted collagenase activity/mg (r=0.18; p=0.0002), collagenase activity/solution volume (r=0.18; p=0.0002) and neutral protease activity/solution volume (r=0.14; p= 0.0029). A statistically significant contribution to the variability of islet yield in a multivariate analysis performed on donor variables was found for donor BMI (p=0.0008). In a multivariate analysis performed on pancreas variables a contribution was found for pancreas weight (p=0.0064), and for a multivariate analysis performed on digestion variables we found a contribution for digestion time (p= 0.0048) and total collagenase activity (p=0.0001). Twenty-four patients with type 1 diabetes received single islet preparations from single donors. In these patients, multivariate analyses showed that the reduction in insulin requirement was significantly associated with morphological aspects of islets (p= 0.0010) and that 1-month C-peptide values were associated with islet purity (p=0.0071). Conclusions/interpretation: These data provide baseline donor, digestion and purification selection criteria for islet isolation using the automated method and indicate that the morphological aspect may be a clinically relevant measure of islets on which the decision for transplant can be based.

Acute insulin response of donors is correlated with pancreatic islet isolation outcome in the pig

“…cause of death, length of intensive care). The predictive value of these non-specific criteria, derived from retrospective cohort analyses [3][4][5][6], remains limited, with the mean success rate of clinical islet isolation hardly surpassing 50% even in the most experienced centres [7,8].…”

“…Unfortunately, the variability of human islet isolation outcome remains an exasperating and expensive issue in clinical islet transplantation [1]. Despite significant technical improvements, results remain highly dependent on donor characteristics and on the conditions of pancreas procurement and storage [3][4][5][6]. Potential donors are, therefore, habitually selected according to non-specific criteria derived from retrospective analysis of large series of human islet isolation [7].…”

Predicting the outcome of islet isolation in large mammals

“…In humans, BMI was found to be the most consistent variable in several large retrospective studies [2]. Although BMI is often used for selecting donors before pancreas retrieval [3], it has only been marginally correlated with the outcome of islet isolation and has little independent predictive value.…”

Surface-Enhanced Raman Spectroscopy-Based Label-Free Insulin Detection at Physiological Concentrations for Analysis of Islet Performance

“…From our measurements, the enhancement factor of the substrate for sensing insulin was calculated to be 3×10 7 . 40 This enhancement primarily originates from the exceptionally strong plasmonic (electromagnetic) enhancement of the 3D Au-NP clusters.…”

“…Before transplantation these islets are screened for their viability and functional response to changing glucose concentration in order to reduce the chances of transplant failure. [7][8][9] Sensors capable of detecting secretion of insulin from beta cells in a costeffective, label-free manner with minimal stress to the cells can serve vital roles in clinical quality assessment of islets. External monitoring of insulin concentration can also help in disease diagnosis and management as well as prevent potentially fatal insulin overdoses or hypoglycemia in diabetic patients.…”