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Assessing islet cellular composition and beta cell viability using Flow Cytometry (FC) and Laser Scanning Cytometry (LSC) may aid in determining the transplant quality of islets. Human islets (2500 IEQ, n = 44, purity >or=80%) dissociated into a single cell suspension were stained with ductal marker CA19, with Newport Green (NG) and FluoZin3 (FL3) for beta-cell identification, with TMRE to assess mitochondrial membrane potential, with DAPI to identify live vs. dead cells, and with Annexin-V/DAPI to differentiate apoptotic and necrotic cells. For LSC, cell preparations (n = 9) were stained for insulin (beta-cells), glucagon (alpha-cells), somatostatin (delta cells), and pancreatic polypeptide (ppp cells). Fluorescence microscopy (EtBr/FDA) and insulin response were also measured. DAPI- staining was 73.78% +/- 1.37, while EtBr/FDA was 96% +/- 0.48. 52.5% +/- 3.73 of all cells were NG+, of which 58.08% +/- 2.61 were NG+/TMRE+. Annexin-V/DAPI staining (n = 26) showed 13.8% +/- 0.89 apoptotic, 27.2% +/- 2.0 necrotic, and 51.9% +/- 2.22 live cells. 26.0% +/- 5.19 of cells were CA19 positive (n = 17), of which 45.5% +/- 4.37 were also TMRE+, and 5.2% +/- 1.2 of the TMRE+ were also NG+/CA19+. NG and FL3 showed similar staining (n = 8). Comparison of short-term (or=3 days) culture showed similar TMRE+/NG+ averages, albeit lower percentages of live (36.4% vs 51.9%), and higher percentages of apoptotic (19.2% vs 13.8%) and necrotic cells (37.4% vs 27.2%) for long-term, as determined by Annexin-V staining. LSC resulted in 54.17% +/- 4.62 beta-cells, 33.33% +/- 4.16 alpha-cells, 8.75% +/- 2.5 delta-cells, and 3.75% +/- 0.79 ppp cells. There is no significant difference between insulin positive cells and NG positive cells (P

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