415 Targeting inflammation and specialized pro-resolving mediators to reinforce barrier function and scalp homeostasis.

Abstract

Specialized pro-resolving lipid mediators (SPMs) are endogeneous lipids that actively regulate the immune system to promote the resolution of inflammation. Although SPMs have been studied in the skin to end the inflammation process and promote tissue regeneration, no studies have been provided in the scalp. The fact that inflammation is one of the key elements of unhealthy scalp that drive to conditions such as dandruff, sebum excess or hair dull and hair loss, led us to investigate the presence and the role of SPMs. For this purpose, an extract of Anetholea anisita, well known for its anti-inflammatory properties, was tested. Anetholea anisita extract, was first investigated in-vitro on human follicle dermal papilla cells (HFDPC) to evaluate its antioxidant and anti-inflammatory properties. The extract was then clinically tested in a rinse-off shampoo formula for 28 days (n=40, 18-40 years) on a population of dandruff sufferers presenting oily hair. All results were compared to the placebo group. Pro-inflammatory markers and SPMs from sebum directly collected on volunteer’s scalps were evaluated by LC-MS/MS. Scalp integrity, by measuring the trans-epidermal water loss (TEWL) and the pH, was also evaluated. Finally, dandruff scoring and hair gloss measurement were achieved. Anetholea anisita exhibited strong antioxidant and anti-inflammatory properties on HFDPC. In-vivo, SPMs were identified for the first time on volunteer’s sebum. The Lipoxin B4 as well as the Resovins D1 and D2 showed an increase after application of the extract. In addition, a decrease of pro-inflammatory markers (PGE2, LTB4 and IL8) was found. Consequently, the scalp barrier was reinforced with improved TEWL and pH balance, to decrease dandruff and improved hair brightness. Overall, these results suggest that acting on the resolution of inflammation represents a promising strategy to improve scalp health. They also bring further support for the concept that targeting scalp disorders helps to improve hair conditions such as dandruff and hair brightness.