Target Cells for Stem Cell Factor in the Adult Islets of Langerhans, Simultaneously Synthesizing Glucagon and Insulin

C-kit—a stem cell receptor, or CD117, is one of the markers of human pancreatic endocrinocyte progenitor cells. Its important role in the proliferation and differentiation of pancreatic endocrine cells during human prenatal development has already been proven. However, the presence and role of c-kit-positive cells in adult pancreatic islets remains unclear. The purpose of our study was to establish the presence of c-kit-positive cells in the adult pancreatic islets and to assess whether they retain the ability to proliferate during a lifetime. We studied pancreatic autopsies of adults aged 50 to 70 years, which were obtained in pathology departments of Kazan hospitals. Samples of the pancreas were embedded in paraffin using standard techniques. Paraffin sections of the pancreas were stained immunohistochemically with commercial antibodies against c-kit, insulin, glucagon, and Ki-67. Few c-kit-positive cells simultaneously secreting insulin or glucagon were detected in all samples studied. These data suggest that such cells are in a state of differentiation into endocrinocytes, but no proliferation of c-kit-positive cells was observed.