New Concepts of Regeneration and Renewal of Adrenal Chromaffin Cells.

Chromaffin cells are neuroendocrine cells found in the adrenal medulla and paraganglia. They represent enigmatic cell population with origins and properties that have undergone a change in scientific interpretations over the last few decades. Earlier concepts consider that chromaffin cells derive from neuronal progenitors, and their cell fate is similar to neurons that lack the ability to proliferate and maintain renewal of cell population in postnatal life. Growing evidence of postnatal proliferation and response to proliferative stimuli were inconsistent with traditional views and required their reassessment and further research on chromaffin cell regeneration sources. The present review summarizes data on embryonic origin and development and transcriptional control of the adrenal chromaffin cells as well as available information about their postnatal proliferation. The authors also represent their findings in cellular and molecular events associated with the physiological transition from organ growth to self-maintenance of cell populations in intact rats and in experimental dismorphogenesis of the adrenals. The authors familiarize readers with available information about the early development and molecular changes in chromaffin cells in postnatal period and propose their new theories concerning mechanisms of adrenomedullary chromaffin cell regeneration. Further research on induction and management of these mechanisms will allow us to maintain cultured chromaffin cells in vitro, which will obviously make a significant contribution to practical regenerative medicine.