Validation of different replication markers for the detection of beta-cell proliferation in human pancreatic tissue

Introduction: Beta-cell-regeneration is considered as a future option for the therapy of diabetes, but the detection of beta-cell replication in human pancreas is still challenging. Therefore, the expression of Ki67, PCNA and MCM-7 in human pancreatic tissue was quantified in order to validate their use as beta-cell replication markers. Methods: Human pancreatic tissue samples were stained for Ki67, PCNA, MCM7, insulin and nuclei, and the expression of replication markers was quantified. Co-expression of the markers was assessed by four-colour fluorescence-staining. Results: All three markers could be detected in endocrine and exocrine tissue. There was a significant correlation between the expression frequencies of all three markers in the exocrine tissue (r>0.49, respectively) and in beta-cells (r>0.95, respectively). A subset of beta-cells with differential expression of the three replication markers was identified. Quantitative analyses revealed that only 36-55% of all exocrine cells expressed two markers at the same time. Conclusions: The expression of Ki67. MCM-7 and PCNA in adult human pancreas is highly correlated, but the labelling of individual cells differs between the markers. The analysis of a combination of markers, preferably MCM7 and Ki67, appears to yield the most reliable results for the determination of beta-cell replication and may allow for a differentiation of cell cycle stages. (C) 2010 Elsevier B.V. All rights reserved.