Adaptability of melanocytes post ultraviolet stimulation in patients with melasma.

BACKGROUND Dynamic in vivo changes in melanin in melasma lesions after exposure to ultraviolet (UV) irradiation have not been described. OBJECTIVES To determine whether melasma lesions and nearby perilesions demonstrated different adaptive responses to UV irradiation and whether the tanning responses were different among different locations on face. METHODS We collected sequential images from real-time cellular resolution full-field optical coherence tomography (CRFF-OCT) at melasma lesions and perilesions among 20 Asian patients. Quantitative and layer distribution analyses for melanin were performed using a computer-aided detection (CADe) system that utilizes spatial compounding-based denoising convolutional neural networks. RESULTS The detected melanin (D) is melanin with a diameter >0.5 µm, among which confetti melanin (C) has a diameter of >3.3 µm and corresponds to a melanosome-rich package. The calculated C/D ratio is proportional to active melanin transportation. Before UV exposure, melasma lesions had more detected melanin (p = 0.0271), confetti melanin (p = 0.0163), and increased C/D ratio (p = 0.0152) in the basal layer compared to those of perilesions. After exposure to UV irradiation, perilesions have both increased confetti melanin (p = 0.0452) and the C/D ratio (p = 0.0369) in basal layer, and this effect was most prominent in right cheek (p = 0.030). There were however no significant differences in the detected, confetti, or granular melanin areas before and after exposure to UV irradiation in melasma lesions in all the skin layers. CONCLUSIONS Hyperactive melanocytes with a higher baseline C/D ratio were noted in the melasma lesions. They were "fixed" on the plateau and were not responsive to UV irradiation regardless of the location on face. Perilesions retained adaptability with a dynamic response to UV irradiation, in which more confetti melanin was shed, mainly in the basal layer. Therefore, aggravating effect of UV on melasma was mainly due to UV-responsive perilesions rather than lesions.

[1]  M. Picardo,et al.  Shining Light on Autophagy in Skin Pigmentation and Pigmentary Disorders , 2022, Cells.

[2]  H. Miot,et al.  Update on Melasma—Part I: Pathogenesis , 2022, Dermatology and Therapy.

[3]  Yen-Jen Wang,et al.  Photoaging and Sequential Function Reversal with Cellular-Resolution Optical Coherence Tomography in a Nude Mice Model , 2022, International journal of molecular sciences.

[4]  M. Seabra,et al.  Reconstructed human pigmented skin/epidermis models achieve epidermal pigmentation through melanocore transfer , 2022, bioRxiv.

[5]  Yen-Jen Wang,et al.  Computer-Aided Detection (CADe) System with Optical Coherent Tomography for Melanin Morphology Quantification in Melasma Patients , 2021, Diagnostics.

[6]  G. Raposo,et al.  Melanin transfer and fate within keratinocytes in human skin pigmentation. , 2021, Integrative and comparative biology.

[7]  Yen-Jen Wang,et al.  Application of Cellular Resolution Full-Field Optical Coherence Tomography in vivo for the Diagnosis of Skin Tumours and Inflammatory Skin Diseases: A Pilot Study , 2021, Dermatology.

[8]  M. Seabra,et al.  Melanin Transfer in the Epidermis: The Pursuit of Skin Pigmentation Control Mechanisms , 2021, International journal of molecular sciences.

[9]  H. Miot,et al.  Deficit in autophagy: A possible mechanism involved in melanocyte hyperfunction in melasma. , 2021, Indian journal of dermatology, venereology and leprology.

[10]  J. Dover,et al.  Microneedling as an adjuvant to topical therapies for melasma: A systematic review and meta-analysis. , 2021, Journal of the American Academy of Dermatology.

[11]  X. Ji,et al.  The thermal dependence and molecular basis of physiological color change in Takydromus septentrionalis (Lacertidae) , 2021, Biology Open.

[12]  K. Kelly,et al.  A Clinical Perspective on the Automated Analysis of Reflectance Confocal Microscopy in Dermatology , 2021, Lasers in surgery and medicine.

[13]  Yin-Quan Tang,et al.  Perspective approaches on melanogenesis inhibition , 2021 .

[14]  B. Lin,et al.  Quantitative Outcome Assessment of Color Match and the Extent of Repigmentation after Pixel Array Epidermal Grafting for Head and Neck Stable Vitiligo: A Prospective Cohort Study , 2020, Dermatology.

[15]  M. Ichihashi,et al.  Dermal Fibroblasts Internalize Phosphatidylserine-Exposed Secretory Melanosome Clusters and Apoptotic Melanocytes , 2020, International journal of molecular sciences.

[16]  H. Chan,et al.  A Systematic Review of Picosecond Laser in Dermatology: Evidence and Recommendations , 2020, Lasers in surgery and medicine.

[17]  B. Lin,et al.  Photoaging Reversibility in Asian Patients With Melasma Treated Using Picosecond Lasers With Diffractive Lens Array: A 1-Year Prospective Observational Cohort Study. , 2020, Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.].

[18]  Erh-Ti Lin,et al.  Prospective Randomised Controlled Trial Comparing Treatment Efficacy and Tolerance of Picosecond Alexandrite Laser with a Diffractive Lens Array and Triple Combination Cream in Female Asian Patients with Melasma. , 2019, Journal of the European Academy of Dermatology and Venereology : JEADV.

[19]  M. Seabra,et al.  The exocyst is required for melanin exocytosis from melanocytes and transfer to keratinocytes , 2020, Pigment cell & melanoma research.

[20]  A. Ganesan,et al.  In vivo multiphoton microscopy of melasma , 2018, Pigment cell & melanoma research.

[21]  H. Miot,et al.  Exploring pathways for sustained melanogenesis in facial melasma: an immunofluorescence study , 2018, International journal of cosmetic science.

[22]  Yen-Jen Wang,et al.  Epidermal grafting for leukoderma resulting from 1064‐nm quality‐switched neodymium‐doped yttrium aluminium garnet laser toning , 2018, International wound journal.

[23]  M. Picardo,et al.  Melasma, a photoaging disorder , 2018, Pigment cell & melanoma research.

[24]  N. Kollias,et al.  Melanin quantification by in vitro and in vivo analysis of near‐infrared fluorescence , 2018, Pigment cell & melanoma research.

[25]  J. Ramalho,et al.  Melanin Transferred to Keratinocytes Resides in Nondegradative Endocytic Compartments. , 2017, The Journal of investigative dermatology.

[26]  M. Stevens,et al.  Camouflage through colour change: mechanisms, adaptive value and ecological significance , 2017, Philosophical Transactions of the Royal Society B: Biological Sciences.

[27]  Kyoung-Chan Park,et al.  Heterogeneous Pathology of Melasma and Its Clinical Implications , 2016, International journal of molecular sciences.

[28]  M. Picardo,et al.  Rab11b mediates melanin transfer between donor melanocytes and acceptor keratinocytes via coupled exo/endocytosis. , 2014, The Journal of investigative dermatology.

[29]  M. Ichihashi,et al.  Melanosomes are transferred from melanocytes to keratinocytes through the processes of packaging, release, uptake, and dispersion. , 2012, The Journal of investigative dermatology.

[30]  P. Bahadoran,et al.  Melasma treatment with pulsed-dye laser and triple combination cream: a prospective, randomized, single-blind, split-face study. , 2011, Archives of dermatology.

[31]  M. Ichihashi,et al.  Involvement of pigment globules containing multiple melanosomes in the transfer of melanosomes from melanocytes to keratinocytes , 2011, Cellular logistics.

[32]  N. Kollias,et al.  Impact of long-wavelength UVA and visible light on melanocompetent skin. , 2010, The Journal of investigative dermatology.

[33]  W. G. Holmes,et al.  Conceptual issues and methodology in kin-recognition research : a critical discussion , 2010 .

[34]  A. Verkleij,et al.  Electron tomography of early melanosomes: Implications for melanogenesis and the generation of fibrillar amyloid sheets , 2008, Proceedings of the National Academy of Sciences.

[35]  S. Lepreux,et al.  Skin Ultrastructure in Senile Lentigo , 2006, Skin Pharmacology and Physiology.

[36]  S. Jee,et al.  The patterns of melanosome distribution in keratinocytes of human skin as one determining factor of skin colour , 2003, The British journal of dermatology.

[37]  G. Hillebrand,et al.  The effect of niacinamide on reducing cutaneous pigmentation and suppression of melanosome transfer , 2002, The British journal of dermatology.