Validation of methodologies for quantifying isolated human islets: an Islet Cell Resources study.
BACKGROUND
Quantification of islet mass is a crucial criterion for defining the quality of the islet product ensuring a potent islet transplant when used as a therapeutic intervention for select patients with type I diabetes.


METHODS
This multi-center study involved all eight member institutions of the National Institutes of Health-supported Islet Cell Resources Consortium. The study was designed to validate the standard counting procedure for quantifying isolated, dithizone-stained human islets as a reliable methodology by ascertaining the accuracy, repeatability (intra-observer variability), and intermediate precision (inter-observer variability). The secondary aim of the study was to evaluate a new software-assisted digital image analysis method as a supplement for islet quantification.


RESULTS
The study demonstrated the accuracy, repeatability and intermediate precision of the standard counting procedure for isolated human islets. This study also demonstrated that software-assisted digital image analysis as a supplemental method for islet quantification was more accurate and consistent than the standard manual counting method.


CONCLUSIONS
Standard counting procedures for enumerating isolated stained human islets is a valid methodology, but computer-assisted digital image analysis assessment of islet mass has the added benefit of providing a permanent record of the isolated islet product being evaluated that improves quality assurance operations of current good manufacturing practice.
Kissler
H J
HJ
Department of Surgery, Northwestern University, Chicago, IL 60611, USA.
Niland
J C
JC
Olack
B
B
Ricordi
C
C
Hering
B J
BJ
Naji
A
A
Kandeel
F
F
Oberholzer
J
J
Fernandez
L
L
Contreras
J
J
Stiller
T
T
Sowinski
J
J
Kaufman
D B
DB
D002469:Cell Separation / Q000379:methods; D048429:Cell Size; D003697:Delphi Technique; D005434:Flow Cytometry; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007515:Islets of Langerhans / Q000166:cytology*; D016381:Islets of Langerhans Transplantation / Q000379:methods; D015203:Reproducibility of Results