Keratinocytes are the predominant cell found in the epidermis, the outermost layer of the skin. In humans, they constitute 90% of epidermal skin cells. Keratinocytes play a pivotal role in hair follicle morphogenesis and cycling.
Keratinocyte activity is a central feature of and provides a direct cellular yard-stick as to the efficacy or lack thereof of any given hair loss intervention.
It has been conclusively demonstrated that in Androgenetic Alopecia, keratinocyte proliferation associated with anagen hair growth is in the affected follicles, significantly inhibited.
To quote from this paper, “Wnt3a-dependent keratinocyte growth was suppressed by the addition of dihydrotestosterone in coculture with DP cells that were derived from AGA patients, but growth was not suppressed in coculture with DP cells from non-AGA males.”
In treating AGA, compounds that promote keratinocyte growth and proliferation are demonstrating efficacy not just on a subjective, observable level, but on a documented cellular level.
Among the many interventions available for intervening on hair loss, only a handful; Minoxidil, Emu Oil, and hydrolyzed Collagen Peptides have been found to confer this specific effect, which is essentially confirmatory regarding intervention efficacy.
Dr. Holick noted this specific mechanism in his patent:
The present invention is directed to the discovery that topical or parenteral administration of emu oil to a mammal stimulates the proliferation of skin. Emu oil can be used to treat skin wrinkles and rejuvenate aged and photo-damaged skin. It has also been discovered that emu oil can be topically applied to stimulate melanogenesis in the skin and to stimulate hair growth. Thus, emu oil is useful to treat pigmentation disorders such as hypopigmentation, stimulating melanogenesis to enhance skin tanning, and treating disorders relating to disturbances in hair cycling such as alopecia, male pattern baldness, female baldness, and chemotherapy-induced alopecia.
“ In order to decrease baldness and accelerate hair generation, it is necessary to bring the hair follicles from the telogen state into the normal anagen state. It has now been found that hair growth is stimulated by administering to a mammal emu oil or a biologically active fraction thereof. This aspect of the present invention has particular utility in the promotion of new hair growth or stimulation of the rate of hair growth, e.g., following chemotherapeutic treatment or for treating a form of alopecia, e.g., male pattern baldness and female hair loss.”
|Follow up studies have confirmed Dr Holick’s findings regarding keratinocyte up-regulation|
Poult Sci 2015 Sep;94(9):2288-96.
Ratite oils promote keratinocyte cell growth and inhibit leukocyte activation
Traditionally, native Australian aborigines have used emu oil for the treatment of inflammation and to accelerate wound healing. Studies on mice suggest that topically applied emu oil may have anti-inflammatory properties and may promote wound healing. We investigated the effects of ratite oils (6 emu, 3 ostrich, 1 rhea) on immortalized human keratinocytes (HaCaT cells) in vitro by culturing the cells in media with oil concentrations of 0%, 0.5%, and 1.0%. Peking duck, tea tree, and olive oils were used as comparative controls. The same oils at 0.5% concentration were evaluated for their influence on peripheral blood mononuclear cell (PBMC) survival over 48 hr and their ability to inhibit IFNγ production in PBMCs activated by phytohemagglutinin (PHA) in ELISpot assays. Compared to no oil control, significantly shorter population doubling time durations were observed for HaCaT cells cultured in emu oil (1.51×faster), ostrich oil (1.46×faster), and rhea oil (1.64×faster). Tea tree oil demonstrated significant antiproliferative activity and olive oil significantly prolonged (1.35×slower) cell population doubling time. In contrast, almost all oils, particularly tea tree oil, significantly reduced PBMC viability. Different oils had different levels of inhibitory effect on IFNγ production with individual emu, ostrich, rhea, and duck oil samples conferring full inhibition. This preliminary investigation suggests that emu oil might promote wound healing by accelerating the growth rate of keratinocytes. Combined with anti-inflammatory properties, ratite oil may serve as a useful component in bandages and ointments for the treatment of wounds and inflammatory skin conditions.
Although we have, and still have long standing reservations about minoxidil usage, it has also been confirmed to stimulate keratinocyte production.
Biphasic effects of minoxidil on the proliferation and
differentiation of normal human keratinocytes
Collagen Peptides, orally consumed are also documented to produce this effect.
Hydrolyzed Collagen Induces an Anti-Inflammatory Response
That Induces Proliferation of Skin Fibroblast and Keratinocytes
Again- stimulating keratinocyte proliferation is a cellular marker that equates to hair growth. Although we generally recommend a multi-faceted approach to treating hair loss, targeting this mechanism alone may understandably be a preferred and effective route by some who have reservations about interventions that affect the hormone axis.