1452-P: PDX1 and CKas Markers of Cell Maturation in the Human Pancreas

Regeneration of beta-cell mass is one of the fundamental problems in diabetology. Embryonic source of all pancreatic cell types is the epithelial cells of the primitive ducts. During pancreas development, epithelial progenitors differentiate in three directions, which is accompanied by changes in cell phenotype, including the expression of various types of cytokeratins, transcription factors, as well as hormones and some other antigens. The early markers of pancreatic epithelial progenitors are the homeodomain transcription factor Pdx 1 (pancreatic and duodenal homeobox 1) and an intermediate filament protein cytokeratin (CK19) . The aim of our work was to analyze the distribution of Pdx1 and CKduring endocrine pancreas development in humans. The study was performed on the pancreatic samples from 27 fetuses (gestational age 14-40 weeks) using double and triple immunohistochemistry with antibodies to Pdx1, CK19, and insulin or glucagon. During human prenatal development, the co-expression of CKand Pdx1 was detected in several cell types. Firstly, it was observed in the epithelial cells of the pancreatic ducts. During the branching of pancreatic ducts, CKexpression decreased in outgrows, while the Pdx1 expression was lowered in large ducts. Secondly, co-expression of CKand Pdx1 was detected in endocrine cells (mainly in alpha) . However, the intensity of the reaction to both markers in these cells was low. Phenotype of beta cells was Pdx1+/ CK19−. At the same time, during development, some cells with an intense reaction to CKand Pdx1 were detected in the forming islets. Apparently, an intense reaction to CK19/Pdx1 may characterized low-differentiated (progenitor) cells that are present in the epithelium of ducts and in the forming islets during the development of the human pancreas. Disclosure A.Proshchina: n/a. Y.Krivova: None. D.Otlyga: None. S.Saveliev: None.