CK19 and PDX1 as Markers of Differentiation and Maturation of Pancreatic Islet Endocrine Cells.

We studied patterns of staining for early cell markers in the forming pancreatic islets during months 5 and 6 of human prenatal development. The study was performed on 10 autopsy specimens of the fetal pancreas (gestational age 16-23 weeks) using multiple immunohistochemical staining with antibodies to PDX1 and CK19. Two main types of cells have been identified: cells with the intense staining for PDX1 and weak or no staining for CK19 that were located in the central area of the mantle islets or at one the poles of bipolar islets and may be referred to a population of β cells and cells with staining for CK19 and weak or no staining for PDX1 that were located at the periphery of the mantle islets or at the other pole of bipolar islets and may be referred to a population of α cells. The islet cells had additional phenotypes based on the staining for CK19 and PDX1, which requires further studies to determine the fate of these cells.