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Endocrine diffuse system. Histological and functional aspects interrelated with tumoral pathology
1Department of Histology, Faculty of Medicine, University of Medicine and Pharmacy "Gr. T. Popa", Iaşi.
Summary
The diffuse neuroendocrine system (DNES) comprises over 40 cell types with diverse origins, challenging the initial neural crest hypothesis. Distinguishing benign from malignant endocrine cell tumors remains difficult due to poorly defined boundaries.
Area of Science:
- Endocrinology
- Cell Biology
- Neuroscience
Background:
- The diffuse neuroendocrine system (DNES) was initially thought to originate solely from neural crest cells.
- Subsequent research identified over 40 distinct DNES cell types with varied developmental origins.
- Only a small subset, approximately 6-7 types, are confirmed to derive from neural crests.
Purpose of the Study:
- To explore the diverse origins and characteristics of diffuse neuroendocrine system cells.
- To highlight the challenges in differentiating benign and malignant neuroendocrine tumors.
- To underscore the overlap in hormones secreted by intestinal endocrine cells and the central nervous system.
Main Methods:
- Fluorescence microscopy to differentiate serotonin (yellow) and catecholamine (green) secreting cells using formaldehyde.
- Silver salt impregnation as a common staining technique for DNES cells.
- Electron microscopy to examine dense granules within endocrine cells and their alterations in malignancies.
Main Results:
- Demonstrated varied origins of DNES cells, contradicting the sole neural crest derivation theory.
- Identified distinct fluorescence patterns for serotonin and catecholamine secreting cells.
- Observed characteristic dense granules in endocrine cells via electron microscopy, with modifications noted in malignant counterparts.
- Found significant overlap between hormones secreted in the intestine and the central nervous system.
- Highlighted the indistinct boundary between benign proliferations and malignant tumors of these cells.
Conclusions:
- DNES cell origins are more complex than previously believed, with multiple sources.
- Standard histological and ultrastructural methods aid in characterizing DNES cells and their pathologies.
- The neuroendocrine system exhibits functional and molecular links between the gut and the brain.
- Further research is needed to refine diagnostic criteria for neuroendocrine tumors.