ANATOMICAL BASIS OF NERVE REGENERATION IN HUMAN SKIN TRANSPLANTS.
G.C.Panzica*°, A.Paraninfo°, A. Garzino°,
G.Ramieri§, M.Calcagni°°, M. Stella°°, S. Teich-Alasia^.
°Dept. Human Anatomy & Physiology, §Dept.Maxillo-Facial
Surgery, °°CTO, Dept. Plastic Surgery and Burn Unit, ^FPSRU, Torino
(Italy)
In recent years the study of the human skin innervation
received new impulses by immunohistochemical techniques. There are, however,
only a few studies dealing with functional markers in both the normal and
transplanted skin. Previous investigations performed in our laboratory
demonstrated the presence of nervous structures, identified by means of
structural markers (PGP 9.5, S-100), also in skin transplants. In the present
study we analyzed the immunoreactivity for both structural (PGP 9.5) and
functional markers of sensitive nerve fibers [calcitonin gene-related peptide
(CGRP), substance P (SP)] in biopsies of skin transplants from several
areas ranging from 3 months to 8 years. The PGP 9.5 immunoreactive structures
are qualitatively distributed in a similar way in normal and transplanted
skin, although a marked reduction was observed in the latest. We detected
the presence of innervated and non-innervated Merkel cells, intraepidermal
fibers, and, in a limited number, that of capsulated receptors. Immunoreactivity
for CGRP is present in almost all the structures detected with PGP 9.5
(including some of the Merkel cells, but not the capsulated receptors),
although their total number is greatly decreased. Finally in some samples
a very limited number of SP-immunoreactive structures (mainly intraepithelial
and intradermal fibers) was observed. Our study shows that regenerating
nervous structures in human skin may exhibit immunocytochemical markers
indicating a potential functional activity. Their number is greatly reduced
in comparison with normal skin, but their qualitative distribution seems
not altered, suggesting the regeneration involves all the different classes
of nerve fibers innervating the skin. Further quantitative studies are
required to understand if functional recovery of the transplant and presence
of neurochemical markers might be related.
This work was supported by FPSRU