Hello,
I recently began researching the long term effects of retinoids on the
appearance of facial skin, and came across this article on Medline,
posted below.   It says that type VII collagen is inhibited by
retinoids, and that this in turn limits the production of anchoring
fibrils.  Forgive me if I sound ignorant here, but is there reason to
think that over time this could accelerate the breakdown of the
structure of the skin, and increase laxity and the appearance of
sagging?

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Authors: Chen M. Goyal S. Cai X. O'Toole EA. Woodley DT.
Institution: Department of Dermatology, Northwestern University
Medical School
Title: Modulation of type VII collagen (anchoring fibril) expression
by retinoids in human skin cells.
Source: Biochimica et Biophysica Acta. 1351(3):333-40, 1997 Apr 10.

Abstract: We examined the effects of retinoids on the expression of
type VII collagen, a major component of anchoring fibrils, in human
keratinocytes and amnion cells (WISH). All-trans retinoic acid (RA) (5
X l0(-6) M) decreased the steady-state levels of type VII collagen
mRNA by at least 80% after 18 h. The inhibition was evident within 6 h
after the addition of RA, maximal at 18 h, and was dose-dependent.
Reduction of type VII mRNA expression also occurred when cell cultures
were incubated with retinol, retinal, and 13-cis RA. Retinoid-mediated
inhibition of type VII collagen mRNA expression was observed in
keratinocytes growing in either serum-free keratinocyte growth medium
(KGM) or KGM supplemented with 1.4 mM Ca2+. Cycloheximide blocked RA-
mediated inhibition of type VII collagen mRNA, demonstrating the need
for de novo protein synthesis. The mRNA levels for fibronectin and
glyceraldehyde phosphate dehydrogenase were not affected by the
retinoids, suggesting selective inhibition on type VII collagen
expression. In addition, the decrease in type VII collagen mRNA was
accompanied by a parallel decrease in secretion of the 290 kDa, type
VII collagen alpha chains.

-Donna