Ultrastructural cytochemistry of the human adrenal medulla

Are Human Adrenal Medullary Chromaffin Cells Adrenaline or Noradrenaline Cells? A Lesson Regarding the Importance of Understanding a Process to Reach a Conclusion

A scientist may realize, during a long academic career, that a widely accepted notion is not actually factual. An example for me is the fraction of adrenaline-secreting cells in human adrenal medullary chromaffin (AMC) cells. Even the authoritative textbooks for medical physiology differ regarding the fraction of adrenaline cells in human AMC cells, stating that it is 80% or 100%. This confusion may be ascribed to the substitution of the fraction of adrenaline in the catecholamines extracted from the human adrenal medulla for the fraction of adrenaline cells in human AMC cells. In this commentary, I look into the possible cause of this substitution and highlight the importance of understanding a process to reach a conclusion.

Organization, fine structure, and viability of the human adrenal medulla: considerations for neural transplantation

Recent reports of adrenal medullary autografts in patients with Parkinson's disease raise several important questions with respect to the cell types actually being transplanted as well as the potential for chromaffin cell banking prior to neural transplantation. In this study, we determined the general morphological characteristics of the human adrenal medulla and assessed factors important for the maintenance of cultured chromaffin cells for later use as transplants. The human adrenal medulla contained islands of cortical cells scattered throughout the gland as well as Schwann cells, nerve endings, endothelial cells, pericytes, isolated ganglionic neurons, and connective tissue elements such as fibroblasts and smooth muscle cells. Because many of these cell types are mitotically active, transplantation of medullary fragments that contain these cells could have far-reaching consequences. One approach that could circumvent the problems arising from multiple cell types in the medulla is differential plating of chromaffin cells prior to transplantation. Differential plating yielded relatively pure populations of chromaffin cells that demonstrated excellent viability if processed within 2 hours after cessation of the gland's circulation. Chromaffin cells cultured in the presence of nerve growth factor exhibited a neuronal phenotype, possessed catecholamine histofluorescence, and displayed tyrosine hydroxylase- and dopamine beta-hydroxylase-like immunoreactivity. The sex and age of the donor did not affect cell viability or morphological characteristics.