Abstract
Purpose: :
To propose a site and mechanism of action of PG induced hair growth based on examination of the correlation of clinical hair growth manifestations with laboratory studies of events in the hair growth cycle.
Methods: :
In this report short-term latanoprost treatment (2-17 days, 3-25.5 ug total dosage) and hair growth findings of 5 patients with elevated IOP were recorded and compared with laboratory findings designed to define the inductive capacity of follicular components. Laboratory evidence used to define inductive signals and sources involved dermal papilla cells micro dissected from rat vibrissa follicles, cultured and then exposed to hair follicle buds. Combinations of cultured and uncultured epidermal and dermal papilla cell preparations from newborn and perinatal mice grafted onto the backs of 150 athymic nude mouse were also evaluated for their ability to induce hair follicle growth.
Results: :
The results of short-term latanoprost Rx were compared with long term therapy in 43 eyes as well as with the results of the laboratory study of hair follicle cells. In all 5 patients initiation of the anagen phase of hair growth induced by short-term latanoprost therapy included greater lash frequency, thickness, length, and pigmentation. In one patient a total low dosage of 3 ug administered over two days caused a complete picture of polytrichia and trichomegaly. Evidence from rat vibrissa dermal papilla cells demonstrated the ability to stimulate hair growth even after being cultured through 14 passages. Evidence from epidermal and dermal cell preparations demonstrated that dermal cells are essential to induce hair growth from very early budding follicles. More developed hair follicles did not require the presence of dermal papilla cells indicating that dermal papilla signals are only required very early in anagen.
Conclusions: :
Very short duration and dosage of PGs induced initiation of anagen in the lash follicles. Laboratory evidence demonstrated that the dermal papilla was the source of the signaling molecules that caused the epithelial germ cells to initiate anagen. Correlation of the clinical and laboratory findings permits the conclusion that PGs act at the dermal papilla to trigger the signaling cascade that causes initiation of anagen.
Keywords: eicosanoids • drug toxicity/drug effects • receptors: pharmacology/physiology