Miliacin Associated with Polar Lipids: Effect on Growth Factors Excretion and Extracellular Matrix of the Dermal Papilla Hair Follicle Model Maintained in Survival Conditions

Background: The Dermal Papilla (DP) consists in specialized dermal fibroblasts located at the base of hair follicles and secreting extracellular matrix, especially collagen and glycosaminoglycans. DP cells are responsible for the production of hair fibers, by inducing anagen phase, and by maintaining the hair in this growth phase. Miliacin (contained in millet oil) is known for its healing properties and activity thereof on cellular proliferation. Miliacin has been associated with polar lipids, which are known to act as a vector, for increasing the bioavailability of the active compounds. Objectives: To explain the cellular hair bulb stimulation by miliacin associated with polar lipids (MPL), we used a model of hair follicle maintained in survival conditions. The modulation of collagen and glycosaminoglycans in the DP, the mitotic index for keratinocytes in the hair bulb and the growth factors excretion (IGF1 and KGF assays) were studied. Materials and Methods: Human hair scalp fragments were maintained in survival conditions for 7 days and treated by MPL diluted in the culture media. Results: A significant increase (14.1%) of IGF1 with an important (140%) and significant stimulation of mitotic index (Ki67 positive cells) was observed in the epithelial cells of hair bulb with MPL. A significant increase (20.8%) of collagen thickness was measured in the connective tissue sheath of the hair in contact with MPL. Conclusion: Miliacin associated with polar lipids acts on dermal papilla where it stimulates IGF1 growth factor production and renewal of keratinocytes in hair bulb. It also increases the thickness of extracellular matrix of the connective tissue sheaths.