Characterization of Ovine Dermal Papilla Cell Aggregation.

Context: The dermal papilla (DP) is a condensation of mesenchymal cells at the proximal end of the hair follicle, which determines hair shaft size and regulates matrix cell proliferation and differentiation. DP cells have the ability to regenerate new hair follicles. These cells tend to aggregate both in vitro and in vivo.

The Effect of Ovine Secreted Soluble Factors on Human Dermal Papilla Cell Aggregation.

Context: In androgenetic alopecia, follicular miniaturization and dynamic changes to the hair cycle produce patterned baldness. The most effective treatment for baldness is hair transplantation surgery. The major limitation to hair transplantation is the availability of donor hair from the relatively unaffected occipital scalp.

The arrector pili muscle, the bridge between the follicular stem cell niche and the interfollicular epidermis.

Proximally, the arrector pili muscle (APM) attaches to the follicular stem cell niche in the bulge, but its distal properties are comparatively unclear. In this work, a novel method employing an F-actin probe, phalloidin, was employed to visualize the APM anatomy. Phalloidin staining of the APM was validated by comparison with conventional antibodies/stains and by generating three-dimensional reconstructions.

Culture of Dermal Papilla Cells from Ovine Wool Follicles: An In Vitro Model for Papilla Size Determination.

Common human balding or hair loss is driven by follicle miniaturization. Miniaturization is thought to be caused by a reduction in dermal papilla size. The molecular mechanisms that regulate papilla size are poorly understood, and their elucidation would benefit from a tractable experimental model.

Hair transplantation in mice: Challenges and solutions.

Hair follicle cells contribute to wound healing, skin circulation, and skin diseases including skin cancer, and hair transplantation is a useful technique to study the participation of hair follicle cells in skin homeostasis and wound healing. Although hair follicle transplantation is a well-established human hair-restoration procedure, follicular transplantation techniques in animals have a number of shortcomings and have not been well described or optimized. To facilitate the study of follicular stem and progenitor cells and their interaction with surrounding skin, we have established a new murine transplantation model, similar to follicular unit transplantation in humans.

Beyond goosebumps: does the arrector pili muscle have a role in hair loss?

The arrector pili muscle (APM) consists of a small band of smooth muscle that connects the hair follicle to the connective tissue of the basement membrane. The APM mediates thermoregulation by contracting to increase air-trapping, but was thought to be vestigial in humans. The APM attaches proximally to the hair follicle at the bulge, a known stem cell niche.

The Germinative Epithelium of Sheep Vibrissae and Wool Follicles has Extensive Proliferative Potential but is Dependent on the Dermal Papilla.

Aim: To investigate the growth potential of keratinocytes derived from the germinative epithelium (GE) of ovine hair follicles. Stem cells from the outer root sheath (ORS) of hair follicles migrate to the GE in the lower follicle where they proliferate and differentiate to form the hair fiber. It has been suggested that the GE comprises transit-amplifying cells and that the duration of anagen is determined by their limited proliferative potential.