A combination of pyridine-2, 4-dicarboxylic acid diethyl ester and resveratrol stabilizes hypoxia-inducible factor 1-alpha and improves hair density in female volunteers.

OBJECTIVE: The aim of this study was first to demonstrate that a combination of pyridine-2, 4-dicarboxylic acid diethyl ester and resveratrol could synergize in vitro on biological pathways associated with hair growth and then to demonstrate the benefit on hair density in a clinical study. METHODS: The effects of pyridine-2, 4-dicarboxylic acid diethyl ester and resveratrol directly on the hypoxic inducible factor-1α protein (HIF-1α) and related genes expression were demonstrated on keratinocytes in culture in vitro using western-blot analysis and real time quantitative polymerase chain reaction analysis. The effect of resveratrol against oxidative stress induced by hydrogen peroxide treatment was studied in hair follicle and hair matrix cells in vitro using the sensitive probe Dichloro-dihydro-fluorescein diacetate (DCFH-DA). Finally, a randomized clinical study on hair density was conducted on 79 Caucasian female subjects to assess the effect of this combination of actives. RESULTS: Pyridine-2, 4-dicarboxylic acid diethyl ester and resveratrol stabilized HIF-1a protein and increased the expression of HIF-1α target genes. Resveratrol significantly reduced the oxygen peroxide-induced oxidative stress generated in hair follicle and hair matrix cells. The clinical study showed that a topical treatment with the combination significantly increased the hair density on women from 1.5 months. CONCLUSION: In addition to the antioxidant properties of resveratrol, the association of pyridine-2, 4-dicarboxylic acid diethyl ester and resveratrol revealed a synergistic effect on the HIF-1α pathway. The results of the clinical study confirmed the importance of such a combination to increase the hair density.

L'alopécie peut affecter 50% des femmes au cours de leur vie ce qui induit une perte de leur estime de soi et une diminution de leur qualité de vie. Au-delà des solutions chirurgicales et des traitements pouvant induire des effets secondaires potentiellement dangereux, il y a un besoin d'améliorer l'efficacité des produits cosmétiques qui permettent de prévenir la chute des cheveux tout en préservant la sécurité des patients. Ainsi, nous avons sélectionné une combinaison de pyridine-2, 4-dicarboxylic acide diethyle ester et de resvératrol pour activer des voies biologiques associées à la croissance du cheveu. Nous avons d'abord montré, in vitro, que la combinaison de pyridine-2, 4-dicarboxylic acide diethyle ester et de resvératrol permet de stabiliser la protéine HIF-1α conduisant ainsi à un effet synergique sur l'expression de gènes clés de la voie HIF-1α. Nous avons aussi démontré, in vitro, que le resvératrol permet de protéger significativement les follicules pileux et les cellules de la matrice du stress oxydatif induit par traitement au peroxide d'hydrogène. En final, une étude clinique randomisée mesurant la densité capillaire a été réalisée sur 79 femmes caucasiennes. Cette étude montre qu'une application topique d'une solution contenant de 5% pyridine-2, 4-dicarboxylic acide diethyle ester et 0.25% de resvératrol augmentent significativement la densité capillaire chez les femmes après 1.5 mois. En conclusion, ces résultats démontrent l'intérêt de stimuler la voie HIF-1α tout en protégeant les cheveux et le scalp du stress oxydatif afin d'améliorer la croissance des cheveux chez les femmes.

Polygonum multiflorum Radix extract protects human foreskin melanocytes from oxidative stress in vitro and potentiates hair follicle pigmentation ex vivo.

OBJECTIVE: To examine the ability of an extract from traditional Chinese medicine, Polygonum multiflorum Radix, to protect melanocyte viability from oxidative stress, a key mechanism in the initiation and progression of hair greying. METHODS: To assess the antioxidant capacity of Polygonum multiflorum Radix extract, primary human foreskin melanocytes were treated with a commercially available Polygonum multiflorum Radix extract added to culture medium and exposed to hydrogen peroxide (H2 O2 ), using intracellular reactive oxygen species concentrations and glutathione/protein ratios as endpoints. To improve solubility for cosmetic uses, a new Polygonum multiflorum Radix extract was derived. As hair greying is the consequence of melanocyte disappearance in an oxidative stress environment, we checked whether the antioxidant capacity of the new Polygonum multiflorum Radix extract could preserve melanocyte viability in response to H2 O2 -induced oxidative stress, and preserve pigmentation within ex vivo human hair follicles. RESULTS: In vitro treatment of primary human foreskin melanocytes with traditional available Polygonum multiflorum Radix extract resulted in decreased intracellular ROS accumulation in response to H2 O2 exposure with a concomitant preservation of glutathione-to-protein ratio, consistent with a protective response against H2 O2 exposure and demonstrating the promise of this extract for protecting melanocytes against oxidative stress. Melanocytes treated with the improved Polygonum multiflorum Radix extract exhibited attenuated H2 O2 -induced cell death, demonstrating a clear cytoprotective effect. Treatment of ex vivo human hair follicles with the improved Polygonum multiflorum Radix extract resulted in a higher level of melanin compared to vehicle-treated controls, demonstrating an ex vivo protective effect on hair pigmentation. CONCLUSION: Polygonum multiflorum Radix extract protects in vitro primary human foreskin melanocytes from the deleterious effects of H2 O2 exposure and improves pigmentation within ex vivo human hair follicles, demonstrating the utility of Polygonum multiflorum Radix extract as a potential active ingredient for the protection of melanocytes against premature death. This data provides in vitro mechanistic evidence consistent with existing in vivo studies for the use of Polygonum multiflorum Radix extract as a strategy for the prevention of oxidative stress-induced hair greying, in line with traditional Polygonum multiflorum Radix uses.

In vitro and in vivo studies with tetra-hydro-jasmonic acid (LR2412) reveal its potential to correct signs of skin ageing.

BACKGROUND: LR2412, a synthetic derivative of jasmonic acid, improved the reconstruction and homeostasis of our organotypic skin models. OBJECTIVES: The need for efficient 'anti-ageing' treatments, in particular for the management of photoaged skin, prompted us to investigate this new ingredient for its potential to correct signs of skin ageing in vitro and in vivo and to identify its mode of action. RESULTS: In vitro, penetration of LR2412 was evaluated using a Franz diffusion cell on excised human skin. Its exfoliating properties and interactions with the stratum corneum were studied using electron microscopy and X-ray diffraction. Experiments were performed on a human reconstructed skin model. In vivo, the effects of LR2412 on steroid-induced skin atrophy, a clinical skin ageing model, were assessed vs. vehicle. A patch test study evaluated its effect on deposition of fibrillin-rich microfibrils in the papillary dermis in clinically photoaged volunteers. A clinical study on the appearance of crow's feet wrinkles was conducted over 3 months of daily application. Penetration studies revealed that LR2412 reaches viable epidermis and superficial dermis, which are skin targets of anti-ageing actives. Within the upper layers of the stratum corneum LR2412 accelerates desquamation and improves the mechanical properties. At the dermal-epidermal junction of reconstructed skin, collagen IV, laminin-5 and fibrillin were stimulated. In vivo, LR2412 reversed steroid-induced atrophy. The patch test model confirms the deposition of fibrillin-rich microfibrils, then an in use clinical study revealed that it reduced facial wrinkles. CONCLUSIONS: The in vitro and in vivo data demonstrate that based on its multiple interactions within human skin, LR2412 has potential to partially correct the signs of ageing in intrinsically and photoaged skin.

6-O glucose linoleate supports in vitro human hair growth and lipid synthesis.

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.

Activation of cytoprotective prostaglandin synthase-1 by minoxidil as a possible explanation for its hair growth-stimulating effect.

Data from the literature indicate that nonsteroidal anti-inflammatory drugs (NSAIDs), such as indomethacin, naproxen, piroxicam, or ibuprofen, induce hair loss in vivo. These NSAIDs are well-known inhibitors of both the cytoprotective isoform of prostaglandin endoperoxide synthase-1 (PGHS-1) and of the inducible form (PGHS-2). By immunohistochemical staining, we found that PGHS-1 is the main isoform present in the dermal papilla from normal human hair follicle (either anagen or catagen), whereas PGHS-2 was only faintly and exclusively expressed in anagen dermal papilla. Thus, PGHS-1 might be the primary target of the hair growth-inhibitory effects of NSAIDs. We thus speculated that activation of PGHS-1 might be a mechanism by which minoxidil (2,4-diamino-6-piperidinopyrimidine-3-oxyde) stimulates hair growth in vivo. We demonstrate here that minoxidil is a potent activator of purified PGHS-1 (AC50 = 80 microM), as assayed by oxygen consumption and PGE2 production. This activation was also evidenced by increased PGE2 production by BALB/c 3T3 fibroblasts and by human dermal papilla fibroblasts in culture. Our findings suggest that minoxidil and its derivatives may have a cytoprotective activity in vivo and that more potent second-generation hair growth-promoting drugs might be designed, based on this mechanism.

Pro-inflammatory cytokine cascade in human plucked hair.

Using reverse transcriptase polymerase chain reaction we showed that freshly plucked human anagen hair expressed both type 1 (80 kD) and type 2 (60 kD) interleukin (IL)-1 receptor mRNAs. The IL-1 receptor type 1 was functional since after in vitro stimulation of plucked hair with IL-1 alpha, we observed the induction of mRNA(s) for the inflammatory cytokines IL-1 beta, tumour necrosis factor alpha and IL-6 as well as for the chemokines monocyte chemotactic and activating factor and IL-8. In addition, the growth of dissected human anagen hairs in culture in vitro was significantly and dose-dependently inhibited by IL-1 alpha as a consequence of hair bulb degradation. These observations, together with those of other authors in IL-1 alpha transgenic mice evidence the inhibitory role of IL-1 on human hair growth. Therefore, in order to identify individuals with high inflammatory potential in their hair follicle environment, we designed a rapid and simple assay to detect variations in the level of IL-1 alpha production in the overnight supernatant of plucked hairs in culture. We observed that 32.7% of the specimens from the volunteers tested (n = 116) could be considered highly inflammatory in terms of IL-1 alpha production. Altogether, these results suggest that in alopecia androgenetica, hair growth might be negatively influenced by IL-1, directly produced by the outer root sheath keratinocytes. Consequently, identifying the "inflammatory alopecic individual' might be of clinical interest to discriminate among individuals for whom anti-IL-1 strategies might be of therapeutic relevance.