Human vomeronasal epithelium development: An immunohistochemical overview

Area of Science:

• Human embryology
• Neuroscience
• Immunohistochemistry

Background:

• The vomeronasal organ (VNO), part of the vomeronasal system (VNS), is a sensory structure in vertebrates.
• Its presence and functionality in humans remain debated, necessitating further investigation into its developmental trajectory.
• Understanding the VNO's developmental changes is crucial for clarifying its role in human sensory perception.

Purpose of the Study:

• To investigate the immunohistochemical changes in the human vomeronasal epithelium during fetal development.
• To assess the expression of neural, neuroendocrine, and epithelial markers in relation to fetal age.
• To evaluate the developmental status and potential regression of the human VNO.

Main Methods:

• Immunohistochemical analysis of 45 human fetuses across three age groups.
• Utilized primary antibodies against neuron-specific enolase, calretinin, neurofilament, chromogranin, synaptophysin, cytokeratin 7, pan-cytokeratin, and S100 protein.
• Performed digital slide analysis, colorimetric segmentation, and surface area measurements.

Main Results:

• The VNO was identified in 42.2% of specimens.
• Neuron-specific enolase and calretinin expression decreased with fetal age, while cytokeratin 7 expression increased.
• Other neural/neuroendocrine markers were negative; S100 protein expression decreased around the VNO.

Conclusions:

• The findings support the theory of neuroepithelial regression in the human VNO during fetal development.
• The observed changes in marker expression indicate a developmental trajectory towards reduced neuroepithelial components.
• This study provides immunohistochemical evidence contributing to the ongoing debate on human VNO functionality.