Improving skin comfort via nervous system modulation

A synthetic tetrapeptide, derived from opioid peptides, has been developed to decrease cutaneous hyper-reactivity to environmental stimuli or irritating agents, by activating the ??opioid receptor. In vivo skin comfort is promoted through a decrease of unpleasant sensations. In a complementary approach, an active rich in omega-3 fatty acids has been developed to promote healthy skin appearance by enhancing in vitro the dopamine release from neurons and by improving in vivo the skin microcirculation. The improvement of skin feeling and appearance is perceivable by the end user.

 Nowadays, the essential role of the skin nervous system is largely acknowledged.1 The skin innervation is formed by two branches: the sensory nerves and the autonomic nerves, playing an essential role in the skin’s adaptation to the outside environment, maintenance of homeostasis and, more generally, wellbeing sensation. Sensory nerves allow the central nervous system to be aware of the physiological or stressed skin state induced by outside factors. Among the several types of sensory nerves, unmyelinated C fibres are the smallest and have the lowest activation threshold for mechanic, thermal and chemical stimuli (low pH, capsaicin). After stimulation they react by sending messages to the central nervous system via activation of vanilloid receptors 1 (TRPV1)2 located on the neuron membrane; the induced action potential generates a nervous influx and then skin discomfort, itching, burning and even pain sensation. In parallel, the sensory nerve endings release locally in the skin pro-inflammatory neuromediators like CGRP (Calcitonin Gene Related Peptide) involved in neurogenic inflammation. An exaggeration of this nerve response is considered to be involved in the phenomenon of hyper-reactive skin, provoking unpleasant sensations that are experienced by half of the population (40% of men and 60% of women).3 The second branch, the skin autonomic nerves, is mainly constituted by sympathetic nerves detected near eccrine glands and blood vessels, regulating sweating and skin blood flow through release of stress hormone, acetylcholine or norepinephrin.1 Sympathetic neurons also release dopamine (catecholamine group),4 a hormone affecting central nervous system processes such as movement control, emotional response and capacity to feel pleasure. In skin, dopamine supports a proper irrigation through a non inflammatory mechanism4 and improves recovery of the skin barrier.5 Therefore, two complementary ways targeting modulation of the cutaneous nervous system have been used to promote skin comfort and wellbeing: reduction of unpleasant skin sensations by endorphin-like approach and skin wellbeing induction by dopamine stimulation.

Reduction of unpleasant skin sensations by endorphin-like approach