Dynamic hormone secretion model : perifusion system
The definitive measure of β-cell quality in an islet is the measurement of β-cell function, i.e., the ability of the islets to release insulin in response to minute changes in ambient glucose levels. Continuous flow or dynamic perifusion of the solution containing glucose and secretagogues through the islets is the most accurate assessment of regulated insulin release in vitro.
Therefore perifusion techiques is a precious tool to investigate the dynamic insulin secretion of human pancreatic islets:
- in response to glucose stimulation
- in response to external stimuli, injury, stress, or new drugs
- to evaluate innovative devices for encapsulation and islet transplantation
Dynamic perifusion predicts islet function in humans
Glucose-stimulated-insulin-secretion index assessed by perifusion techniques reflects insulin secretion in human islets transplanted patients
Insulin secretion pattern and magnitude are heterogeneous among islet preparations. Schematic representation of standard glucose-mediated insulin secretion by perifusion for islet quality determination. Secretion values of absolute insulin (µIU/ml/min; red curve) and glucose (g/L; blue curve). B: basal, S1: stimulatory phase 1, S2: stimulatory phase 2.
Dynamic perifusion-derived insulin secretion profiles of 61 islet preparations. B: basal, S1: stimulatory phase 1, S2: stimulatory phase 2.
An added value of perfusion is that although the results are comparable to those by static incubation, the secretion indices obtained by perfusion are higher and correlate with the functionality of pancreatic islets transplanted in vivo into diabetic subjects, making it a unique technique to predict in vitro the functionality of islets in response to a drug or a stimulus.
