The substitution of natural, bio-based and/or biodegradable polymers for those of petrochemical origin in consumer formulations has become an active area of research and development as the sourcing and destiny...

No abstract

The skin is the organ that is most susceptible to the impact of the exposome.Located at the interface with the external environment, it protects internal organs through the barrier function of the epidermis. It must adapt to the consequences of the harmful effects of solar radiation, the various chemical constituents of atmospheric pollution, and wounds associated with mechanical damage: oxidation, cytotoxicity, inflammation, and so forth. In this biological context, a capacity to adapt to the various stresses caused by the exposome is essential; otherwise, more or less serious conditions may develop accelerated aging, pigmentation disorders, atopy, psoriasis, and skin cancers. Nrf2-controlled pathways play a key role at this level. Nrf2 is a transcription factor that controls genes involved in oxidative stress protection and detoxification of chemicals. Its involvement in UV protection, reduction of inflammation in processes associated with healing, epidermal differentiation for barrier function, and hair regrowth, has been demonstrated. The modulation of Nrf2 in the skin may therefore constitute a skin protection or care strategy for certain dermatological stresses and disorders initiated or aggravated by the exposome. Nrf2 inducers can act through different

NAD(+) dependent 15-hydroxyprostaglandin dehydrogenate (15-PGDH) catalyses oxidation of 15(S)-hydroxyl group of prostaglandins and as a result inactivates their physiological potential. Positive effects of prostaglandins or prostaglandin analogues were reported on terminal hair, vellus hair or eyelash growth and a complex prostaglandin network was recently described in human hair follicle. In the present study, we showed that 15-PGDH was expressed in human hair follicle mainly in melanocytes and keratinocytes, which brought us to consider this enzyme as a possible target to sustain local prostaglandin production. Using a recombinant enzymatic strategy, specific 15-PGDH inhibitors were screened. We identified a thiazolidine dione derivative exhibiting efficacy on follicular outer root sheath keratinocytes, since it concomitantly decreased the production of deactivated 13,14 dihydro 15-ketoprostaglandin F(2alpha) and sustained prostaglandin F(2alpha)in vitro production. In the context of recent interest in prostaglandins and prostaglandin analogues as hair regrowth agents, we postulated that the use of selected 15-PGDH inhibitors could reinforce or prolong the effect of these physiological mediators on hair and skin.

The hair follicle is a very active organ with a complex structure, which produces a hair fibre at a rate of 0.3 mm a day. Accordingly, the hair follicle is highly demanding in energy source, as the hair bulb matrix cells are endowed with one of the highest rates of proliferation in the human body. Moreover, recent data have shown the involvement of lipids in hair follicle function. As in vitro-grown hair follicle keeps producing a hair fibre that closely resembles the natural hair fibre, we decided to use this model to investigate the role of a new of glucose linoleate derivative (6-O-linoleyl-d-glucose: 6-O-GL) as a lipid precursor and energy provider. Our results demonstrated that 6-O-GL was (i) quite stable and surprisingly resistant to oxidative degradation, and (ii) readily taken up and metabolized by the hair follicle into various lipids, namely neutral lipids, ceramides and polar lipids. Moreover, it supported hair follicle growth and survival in a glucose- and linoleic-acid free medium. 6-O-GL thus appeared to be a bi-functional nutrient, ensuring both proper fibre quality and production by the hair follicle.