A Detailed Protocol for Dynamic Islet Perifusion

Since the publication of the Edmonton protocol in 2000, the number of studies to further improve the clinical islet transplantation process has increased tremendously. Perifusion systems allow scientists to examine the responsiveness of isolated islets in an environment that is designed to more closely mimic in vivo conditions.

This involves bathing the islets in fluids containing glucose or other agents that stimulate insulin release. Perfusate samples can then be collected and used for biomarker analyses.

There are a variety of perifusion systems being used in laboratories around the world.  Standardization and reliability of such methods are of particular concern to those working in the clinical transplantation field. Bensti-Barnes and colleagues set out to answer these concerns in the recent publication of their dynamic perifusion procedure.  An important goal of this work was to provide a detailed and validated method for assessing b-cell function.

In this study, insulin secretion was measured after stimulation with glucose (with or without potassium chloride), carbachol or Exendin 4.  Various technical aspects were addressed including temperature regulation, insulin degradation, islet viability and robust insulin measurements. The authors concluded that the cost-effective perifusion procedure they used provides highly repeatable and reproducible data, and can be modified for use in any laboratory.

An important part of obtaining robust results in these types of studies is the use of a high quality biomarker assay.  Bentsi-Barnes and colleagues used the Mercodia Insulin ELISA to determine insulin concentrations in perfusate samples.  This assay is also the approved method for the Clinical Islet Transplantation (CIT) Consortium’s glucose-stimulated insulin release (GSIR) studies.

Bentsi-Barnes et al. (2011) Detailed protocol for evaluation of dynamic perifsuion of human islets to assess b-cell function. Islets 3:284-290