Effect of topical application of raspberry ketone on dermal production of insulin-like growth factor-I in mice and on hair growth and skin elasticity in humans.
Sensory neurons release calcitonin gene-related peptide (CGRP) on activation. We recently reported that topical application of capsaicin increases facial skin elasticity and promotes hair growth by increasing dermal insulin-like growth factor-I (IGF-I) production through activation of sensory neurons in mice and humans. Raspberry ketone (RK), a major aromatic compound contained in red raspberries (Rubus idaeus), has a structure similar to that of capsaicin. Thus, it is possible that RK activates sensory neurons, thereby increasing skin elasticity and promoting hair growth by increasing dermal IGF-I production. In the present study, we examined this possibility in mice and humans. RK, at concentrations higher than 1muM, significantly increased CGRP release from dorsal root ganglion neurons (DRG) isolated from wild-type (WT) mice and this increase was completely reversed by capsazepine, an inhibitor of vanilloid receptor-1 activation. Topical application of 0.01% RK increased dermal IGF-I levels at 30min after application in WT mice, but not in CGRP-knockout mice. Topical application of 0.01% RK increased immunohistochemical expression of IGF-I at dermal papillae in hair follicles and promoted hair re-growth in WT mice at 4 weeks after the application. When applied topically to the scalp and facial skin, 0.01% RK promoted hair growth in 50.0% of humans with alopecia (n=10) at 5 months after application and increased cheek skin elasticity at 2 weeks after application in 5 females (p<0.04). These observations strongly suggest that RK might increase dermal IGF-I production through sensory neuron activation, thereby promoting hair growth and increasing skin elasticity.
Traduzione
Neuroni sensoriali rilascio calcitonina gene-correlato peptide (CGRP), su attivazione. Abbiamo recentemente riferito che l'applicazione topica di capsaicina aumenta l'elasticità della pelle del viso e promuove la crescita dei capelli, aumentando cutanea insulin-like growth factor-I (IGF-I), la produzione attraverso l'attivazione di neuroni sensoriali nei topi e nell'uomo. Lampone chetone (RK), uno dei principali composti aromatici contenuti in rosso lamponi (Rubus idaeus), ha una struttura simile a quella di capsaicina. Così, è possibile che i neuroni sensoriali RK attiva, quindi, di aumentare l'elastic
Sensory neurons release calcitonin gene-related peptide (CGRP) on activation. We recently reported that topical application of capsaicin increases facial skin elasticity and promotes hair growth by increasing dermal insulin-like growth factor-I (IGF-I) production through activation of sensory neurons in mice and humans. Raspberry ketone (RK), a major aromatic compound contained in red raspberries (Rubus idaeus), has a structure similar to that of capsaicin. Thus, it is possible that RK activates sensory neurons, thereby increasing skin elasticity and promoting hair growth by increasing dermal IGF-I production. In the present study, we examined this possibility in mice and humans. RK, at concentrations higher than 1muM, significantly increased CGRP release from dorsal root ganglion neurons (DRG) isolated from wild-type (WT) mice and this increase was completely reversed by capsazepine, an inhibitor of vanilloid receptor-1 activation. Topical application of 0.01% RK increased dermal IGF-I levels at 30min after application in WT mice, but not in CGRP-knockout mice. Topical application of 0.01% RK increased immunohistochemical expression of IGF-I at dermal papillae in hair follicles and promoted hair re-growth in WT mice at 4 weeks after the application. When applied topically to the scalp and facial skin, 0.01% RK promoted hair growth in 50.0% of humans with alopecia (n=10) at 5 months after application and increased cheek skin elasticity at 2 weeks after application in 5 females (p<0.04). These observations strongly suggest that RK might increase dermal IGF-I production through sensory neuron activation, thereby promoting hair growth and increasing skin elasticity.
Traduzione
Neuroni sensoriali rilascio calcitonina gene-correlato peptide (CGRP), su attivazione. Abbiamo recentemente riferito che l'applicazione topica di capsaicina aumenta l'elasticità della pelle del viso e promuove la crescita dei capelli, aumentando cutanea insulin-like growth factor-I (IGF-I), la produzione attraverso l'attivazione di neuroni sensoriali nei topi e nell'uomo. Lampone chetone (RK), uno dei principali composti aromatici contenuti in rosso lamponi (Rubus idaeus), ha una struttura simile a quella di capsaicina. Così, è possibile che i neuroni sensoriali RK attiva, quindi, di aumentare l'elastic
