Publications by authors named "Jean Francois Michelet"

Hair thinning occurs during normal chronological aging in women and in men leading to an increased level of thinner hair shafts alongside original thicker shafts. However, the characteristics of age-associated thin hairs remain largely unknown. Here we analyzed these characteristics by comparing at multiscale thin and thick hairs originated from Caucasian women older than 50 years.

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Androgenic alopecia (AGA) is a common and chronic condition. It may impact self-esteem, self-image and quality of life. Benefit, tolerability, cosmetic acceptance and patient satisfaction are key to ensure good treatment outcome.

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Background: Jasmonates are plant hormones that exhibit anti-cancer and anti-inflammatory properties and have therefore raised interest for human health applications. The molecular basis of these activities remains poorly understood, although increasing evidence suggests that a variety of mechanisms may be involved. Recently, we have reported that a jasmonate derivative (JAD) displayed anti-aging effects on human skin by inducing extracellular matrix (ECM) remodeling.

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Dermal fibroblasts are responsible for the generation of mechanical forces within their surrounding extracellular matrix and can be potentially targeted by anti-aging ingredients. Investigation of the modulation of fibroblast contraction by these ingredients requires the implementation of three-dimensional in situ imaging methodologies. We use multiphoton microscopy to visualize unstained engineered dermal tissue by combining second-harmonic generation that reveals specifically fibrillar collagen and two-photon excited fluorescence from endogenous cellular chromophores.

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Article Synopsis
  • - The study aimed to assess the melanogenic activity of human hair follicles using [14C]-2-thiouracil, which integrates into melanin.
  • - Results showed that [14C]-2-TU was mainly incorporated in pigmented hair follicles, particularly around the dermal papilla and within the hair fiber, with increased incorporation when treated with forskolin, linked to elevated tyrosinase levels.
  • - In contrast, the competitive inhibitor kojic acid led to a significant decrease in [14C]-2-TU incorporation, while the MC1-R agonist alpha-MSH did not result in notable changes, highlighting the potential of this model for studying hair pigmentation regulators.
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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.

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Article Synopsis
  • TRP-2, an enzyme involved in melanin production, impacts how melanocytes respond to stress and was studied in the WM35 melanoma cell line.
  • Overexpressing TRP-2 increased cell survival against oxidative stress, protected DNA from damage, and raised glutathione levels, a key antioxidant.
  • However, the protective effects of TRP-2 were not observed in HEK epithelial cells, suggesting the benefits depend on the specific cell type or environment.
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Prostanoid pathway in hair follicle gained closer attention since trichogenic side-effects on hair growth has been observed concomitantly with prostaglandin F(2alpha) receptor (FP) agonist treatment of intraocular pressure. We thus investigated prostanoid receptor distribution in anagen hair follicle and different cell types from hair and skin. Using RT-PCR, Western blot and immunohistochemistry (IHC), we found that all receptors were present in hair follicle.

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Prostaglandins regulate a wide number of physiological functions. Recently PGF(2alpha) analogue such as latanoprost was shown to have a real impact on hair regrowth. The aim of this study was to investigate and describe the expression profile in human hair follicle of prostaglandin metabolism key enzymes, i.

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