Spatial Distributionof StemCell-Like keratinocytes in Dissected Compound Hair Follicles of the Dog
Authors
Dominique J. Wiener, Marcus G. Doherr, Eliane J. Müller, Monika M. Welle
Institution
University of Bern
Country
Switzerland
Year
2016
Journal
PLOS One
Abstract
Hair cycle disturbances are common in dogs and comparable to some alopecic disorders in
humans. A normal hair cycle is maintained by follicular stem cells which are predominately
found in an area known as the bulge. Due to similar morphological characteristics of the
bulge area in humans and dogs, the shared particularity of compound hair follicles as well
as similarities in follicular biomarker expression, the dog is a promising model to study
human hair cycle and stem cell disorders. To gain insight into the spatial distribution of follicular
keratinocytes with stem cell potential in canine compound follicles, we microdissected
hair follicles in anagen and telogen from skin samples of freshly euthanized dogs. The keratinocytes
isolated from different locations were investigated for their colony forming efficiency,
growth and differentiation potential as well as clonal growth. Our results indicate that
i) compound and single hair follicles exhibit a comparable spatial distribution pattern with
respect to cells with high growth potential and stem cell-like characteristics, ii) the lower isthmus
(comprising the bulge) harbors most cells with high growth potential in both, the anagen
and the telogen hair cycle stage, iii) unlike in other species, colonies with highest
growth potential are rather small with an irregular perimeter and iv) the keratinocytes
derived from the bulbar region exhibit characteristics of actively dividing transit amplifying
cells. Our results now provide the basis to conduct comparative studies of normal dogs and
those with hair cycle disorders with the possibility to extend relevant findings to human
patients.