Note: Among cell populations of HF the folloving are the most important:
- Cells of epithelial origin: matrix trichocytes [M] and ORS [outer root sheath] cells.
- Cells of dermal origin: DP fibroblasts and dermal sheath [DS] fibroblasts.
The last play in HF predominantly regulation role, while the former represent mitotically active populations.
In vitro, DS and ORS cells, when cultured together in 3-D gel produce 2 types of structures:
Sphere-shaped pearls with keratinous type of terminal differentiation of ORS.
Root-like structures. Type of terminal differentiation of ORS was not established here.
JAHODA CA., REYNOLDS AJ ., Dermal- epidermal interaction . Follicle derived cell populations in the study of hair growth mechanism . // J. Invest. Dermatol. 1993 vol. 101 p. 33s-38s
Thus, distal DS play the following functions:
Regenerative function – it regenerate new DP.
Regulatory role – it control migration, proliferation and terminal differentiation of epithelial cells of HF.
Concerning proximal DS, there is no single opinion about it potentialities. Most recent experiments indicate, that its cells can [yet in smaller extent] regenerate new HFs and specifically control terminal differentiation of trichocytes |
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