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Vasudevan S, Vogt WC, Weininger S, Pfefer TJ. Melanometry for objective evaluation of skin pigmentation in pulse oximetry studies. COMMUNICATIONS MEDICINE 2024; 4:138. [PMID: 38992188 PMCID: PMC11239860 DOI: 10.1038/s43856-024-00550-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 06/11/2024] [Indexed: 07/13/2024] Open
Abstract
Pulse oximetry enables real-time, noninvasive monitoring of arterial blood oxygen levels. However, results can vary with skin color, thus detecting disparities during clinical validation studies requires an accurate measure of skin pigmentation. Recent clinical studies have used subjective methods such as self-reported color, race/ethnicity to categorize skin. Melanometers based on optical reflectance may offer a more effective, objective approach to assess pigmentation. Here, we review melanometry approaches and assess evidence supporting their use as clinical research tools. We compare performance data, including repeatability, robustness to confounders, and compare devices to each other, to subjective methods, and high-quality references. Finally, we propose best practices for evaluating melanometers and discuss alternate optical approaches that may improve accuracy. Whilst evidence indicates that melanometers can provide superior performance to subjective approaches, we encourage additional research and standardization efforts, as these are needed to ensure consistent and reliable results in clinical studies.
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Affiliation(s)
- Sandhya Vasudevan
- Center for Devices and Radiological Health, Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD, 20993, USA.
| | - William C Vogt
- Center for Devices and Radiological Health, Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD, 20993, USA
| | - Sandy Weininger
- Center for Devices and Radiological Health, Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD, 20993, USA
| | - T Joshua Pfefer
- Center for Devices and Radiological Health, Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD, 20993, USA
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2
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Snyman M, Walsdorf RE, Wix SN, Gill JG. The metabolism of melanin synthesis-From melanocytes to melanoma. Pigment Cell Melanoma Res 2024; 37:438-452. [PMID: 38445351 PMCID: PMC11178461 DOI: 10.1111/pcmr.13165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 02/06/2024] [Accepted: 02/18/2024] [Indexed: 03/07/2024]
Abstract
Melanin synthesis involves the successful coordination of metabolic pathways across multiple intracellular compartments including the melanosome, mitochondria, ER/Golgi, and cytoplasm. While pigment production offers a communal protection from UV damage, the process also requires anabolic and redox demands that must be carefully managed by melanocytes. In this report we provide an updated review on melanin metabolism, including recent data leveraging new techniques, and technologies in the field of metabolism. We also discuss the many aspects of melanin synthesis that intersect with metabolic pathways known to impact melanoma phenotypes and behavior. By reviewing the metabolism of melanin synthesis, we hope to highlight outstanding questions and opportunities for future research that could improve patient outcomes in pigmentary and oncologic disease settings.
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Affiliation(s)
- Marelize Snyman
- Dermatology Department, University of Texas Southwestern Medical Center, Dallas, Texas, 75235
| | - Rachel E. Walsdorf
- Dermatology Department, University of Texas Southwestern Medical Center, Dallas, Texas, 75235
| | - Sophia N. Wix
- Dermatology Department, University of Texas Southwestern Medical Center, Dallas, Texas, 75235
| | - Jennifer G. Gill
- Dermatology Department, University of Texas Southwestern Medical Center, Dallas, Texas, 75235
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Pachyn E, Aumiller M, Freymüller C, Linek M, Volgger V, Buchner A, Rühm A, Sroka R. Investigation on the influence of the skin tone on hyperspectral imaging for free flap surgery. Sci Rep 2024; 14:13979. [PMID: 38886457 PMCID: PMC11183063 DOI: 10.1038/s41598-024-64549-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 06/10/2024] [Indexed: 06/20/2024] Open
Abstract
Hyperspectral imaging (HSI) is a new emerging modality useful for the noncontact assessment of free flap perfusion. This measurement technique relies on the optical properties within the tissue. Since the optical properties of hemoglobin (Hb) and melanin overlap, the results of the perfusion assessment and other tissue-specific parameters are likely to be distorted by the melanin, especially at higher melanin concentrations. Many spectroscopic devices have been shown to struggle with a melanin related bias, which results in a clinical need to improve non-invasive perfusion assessment, especially for a more pigmented population. This study investigated the influence of skin tones on tissue indices measurements using HSI. In addition, other factors that might affect HSI, such as age, body mass index (BMI), sex or smoking habits, were also considered. Therefore, a prospective feasibility study was conducted, including 101 volunteers from whom tissue indices measurements were performed on 16 different body sites. Skin tone classification was performed using the Fitzpatrick skin type classification questionnaire, and the individual typology angle (ITA) acquired from the RGB images was calculated simultaneously with the measurements. Tissue indices provided by the used HSI-device were correlated to the possible influencing factors. The results show that a dark skin tone and, therefore, higher levels of pigmentation influence the HSI-derived tissue indices. In addition, possible physiological factors influencing the HSI-measurements were found. In conclusion, the HSI-based tissue indices can be used for perfusion assessment for people with lighter skin tone levels but show limitations in people with darker skin tones. Furthermore, it could be used for a more individual perfusion assessment if different physiological influencing factors are respected.
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Affiliation(s)
- Ester Pachyn
- Department of Urology, Laser-Forschungslabor, LIFE Center, University Hospital, LMU Munich, Fraunhoferstrasse 20, 82152, Planegg, Germany.
| | - Maximilian Aumiller
- Department of Urology, Laser-Forschungslabor, LIFE Center, University Hospital, LMU Munich, Fraunhoferstrasse 20, 82152, Planegg, Germany
- Department of Urology, University Hospital, LMU Munich, 81377, Munich, Germany
| | - Christian Freymüller
- Department of Urology, Laser-Forschungslabor, LIFE Center, University Hospital, LMU Munich, Fraunhoferstrasse 20, 82152, Planegg, Germany
- Department of Urology, University Hospital, LMU Munich, 81377, Munich, Germany
| | - Matthäus Linek
- Department of Urology, Laser-Forschungslabor, LIFE Center, University Hospital, LMU Munich, Fraunhoferstrasse 20, 82152, Planegg, Germany
| | - Veronika Volgger
- Department of Otorhinolaryngology, University Hospital, LMU Munich, 81377, Munich, Germany
| | - Alexander Buchner
- Department of Urology, University Hospital, LMU Munich, 81377, Munich, Germany
| | - Adrian Rühm
- Department of Urology, Laser-Forschungslabor, LIFE Center, University Hospital, LMU Munich, Fraunhoferstrasse 20, 82152, Planegg, Germany
- Department of Urology, University Hospital, LMU Munich, 81377, Munich, Germany
| | - Ronald Sroka
- Department of Urology, Laser-Forschungslabor, LIFE Center, University Hospital, LMU Munich, Fraunhoferstrasse 20, 82152, Planegg, Germany
- Department of Urology, University Hospital, LMU Munich, 81377, Munich, Germany
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Shinde VR, Thanekar AM, Khatun S, Buddhiraju HS, Bhattacharjee B, Rengan AK. Melanin-Ce6-loaded polydopamine nanoparticles-based enhanced phototherapy for B16 melanoma cancer cells. NANOTECHNOLOGY 2024; 35:295101. [PMID: 38593752 DOI: 10.1088/1361-6528/ad3c4a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 04/09/2024] [Indexed: 04/11/2024]
Abstract
Melanoma is one of the most aggressive and lethal types of cancer owing to its metastatic propensity and chemoresistance property. An alternative therapeutic option is photodynamic and photothermal therapies (PDT/PTT), which employ near-infrared (NIR) light to generate heat and reactive oxygen species (ROS). As per previous reports, Melanin (Mel), and its synthetic analogs (i.e. polydopamine nanoparticles) can induce NIR light-mediated heat energy, thereby selectively targeting and ameliorating cancer cells. Similarly, chlorin e6 (Ce6) also has high ROS generation ability and antitumor activity against various types of cancer. Based on this tenet, In the current study, we have encapsulated Mel-Ce6 in a polydopamine (PDA) nanocarrier (MCP NPs) synthesized by the oxidation polymerization method. The hydrodynamic diameter of the synthesized spherical MCP NPs was 139 ± 10 nm. The MCP NPs, upon irradiation with NIR 690 nm laser for 6 min, showed photothermal efficacy of more than 50 °C. Moreover, the red fluorescence in the MCP NPs due to Ce6 can be leveraged for diagnostic purposes. Further, the MCP NPs exhibited considerable biocompatibility with the L929 cell line and exerted nearly 70% ROS-mediated cytotoxicity on the B16 melanoma cell line after the laser irradiation. Thus, the prepared MCP NPs could be a promising theranostic agent for treating the B16 melanoma cancer.
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Affiliation(s)
- Vinod Ravasaheb Shinde
- Department of Biomedical Engineering, Indian Institute of Technology Hyderabad, Kandi, Telangana, 502284, India
| | - Ajinkya Madhukar Thanekar
- Department of Biomedical Engineering, Indian Institute of Technology Hyderabad, Kandi, Telangana, 502284, India
| | - Sajmina Khatun
- Department of Biomedical Engineering, Indian Institute of Technology Hyderabad, Kandi, Telangana, 502284, India
| | - Hima Sree Buddhiraju
- Department of Biomedical Engineering, Indian Institute of Technology Hyderabad, Kandi, Telangana, 502284, India
| | - Basu Bhattacharjee
- Department of Biomedical Engineering, Indian Institute of Technology Hyderabad, Kandi, Telangana, 502284, India
| | - Aravind Kumar Rengan
- Department of Biomedical Engineering, Indian Institute of Technology Hyderabad, Kandi, Telangana, 502284, India
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Goh CL, Kang HY, Morita A, Zhang C, Wu Y, Prakoeswa CRS, Sau NH, Kerob D, Flament F, Wei L. Awareness of sun exposure risks and photoprotection for preventing pigmentary disorders in Asian populations: Survey results from three Asian countries and expert panel recommendations. PHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE 2024; 40:e12932. [PMID: 38059515 DOI: 10.1111/phpp.12932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 11/07/2023] [Accepted: 11/09/2023] [Indexed: 12/08/2023]
Abstract
BACKGROUND In this article, we review and discuss the photoprotection behavior of Asians based on the literature, along with a subanalysis of an original online survey, and make recommendations to optimize photoprotection for Asian populations to prevent photoaging and pigmentary disorders. METHODS An international panel of eight dermatologists from Asia (China, Korea, Japan, Singapore, Indonesia, and Vietnam) met to discuss sunscreen photoprotection for Asian patients. Additionally, a subanalysis of an online survey by 3000 respondents from three Asian countries (China, Indonesia, and Japan) investigated general public awareness and attitudes to sun exposure. RESULTS A pre-meeting survey of the eight experts from Asia showed key concerns of Asian patients consulting dermatologists are pigmentary disorders, especially actinic/senile lentigo, post-inflammatory hyperpigmentation, melasma, vitiligo, and Hori's nevus. The survey subanalysis of participants from China, Indonesia, and Japan with predominantly Fitzpatrick skin types (FST) II to IV revealed that they are particularly concerned about sun exposure causing photoaging and pigmentary disorders. Most of the respondents indicated they have limited knowledge on sunlight radiation and appropriate sunscreen protection factors. Only 22%, 13%, and 3% for China, Indonesia, and Japan, respectively, systematically use multiple protective measures (using sunscreen, avoiding midday sun, staying in the shade, wearing a hat, protective clothing, and sunglasses) when exposed to the sun. CONCLUSIONS Further education is needed for Asian populations on the importance of comprehensive daily photoprotection, including broad-spectrum sunscreen, with high UVA and visible light protection, to reduce and prevent photoaging and pigmentary disorders.
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Affiliation(s)
| | - Hee Young Kang
- Department of Dermatology, Ajou University School of Medicine, Suwon, South Korea
| | - Akimichi Morita
- Department of Geriatric and Environmental Dermatology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Chengfeng Zhang
- Department of Dermatology, Huashan Hospital, Fudan University, Shanghai, China
| | - Yan Wu
- Department of Dermatology, Peking University First Hospital, Beijing, China
| | - Cita Rosita Sigit Prakoeswa
- Department of Dermatology and Venerology, Faculty of Medicine, Universitas Airlangga - Dr Soetomo General Academic Hospital, Surabaya, East Java, Indonesia
| | - Nguyen Huu Sau
- Hanoi Medical University and National Hospital of Dermatology and Venereology, Hanoi, Vietnam
| | - Delphine Kerob
- Laboratoire Dermatologique La Roche-Posay, Levallois-Perret, France
| | | | - Liu Wei
- Department of Dermatology, The General Hospital of Air Force PLA, Beijing, China
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Roulin A, Dubey S, Ito S, Wakamatsu K. Melanin-based plumage coloration and melanin content in organs in the barn owl. JOURNAL OF ORNITHOLOGY 2023; 165:429-438. [PMID: 38496038 PMCID: PMC10940376 DOI: 10.1007/s10336-023-02137-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 11/22/2023] [Accepted: 11/28/2023] [Indexed: 03/19/2024]
Abstract
Although the evolutionary ecology of melanin pigments and melanin-based coloration has been studied in great details, particularly in birds, little is known about the function of melanin stored inside the body. In the barn owl Tyto alba, in which individuals vary in the degree of reddish pheomelanin-based coloration and in the size of black eumelanic feather spots, we measured the concentration in melanin pigments in seven organs. The eyes had by far the most melanin then the skin, pectoral muscle, heart, liver, trachea, and uropygial gland. The concentration in eumelanin was not necessarily correlated with the concentration in pheomelanin suggesting that their production can be regulated independently from each other. Redder barn owls had more pheomelanin in the skin and uropygial gland than white owls, while owls displaying larger black feather spots had more eumelanin in the skin than small-spotted owls. More data are required to evaluate whether melanin-based traits can evolve as an indirect response to selection exerted on melanin deposition in organs.
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Affiliation(s)
- Alexandre Roulin
- Department of Ecology and Evolution, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
| | - Sylvain Dubey
- Department of Ecology and Evolution, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
- HW Romandie SA, Avenue Des Alpes 25, CH-1820 Montreux, Switzerland
| | - Shosuke Ito
- Institute for Melanin Chemistry, Fujita Health University, Toyoake, Aichi 470-1192 Japan
| | - Kazumasa Wakamatsu
- Institute for Melanin Chemistry, Fujita Health University, Toyoake, Aichi 470-1192 Japan
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Mazur E, Kwiatkowska D, Reich A. Photodynamic Therapy in Pigmented Basal Cell Carcinoma-A Review. Biomedicines 2023; 11:3099. [PMID: 38002098 PMCID: PMC10669876 DOI: 10.3390/biomedicines11113099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 11/16/2023] [Accepted: 11/19/2023] [Indexed: 11/26/2023] Open
Abstract
This review summarizes the effectiveness of photodynamic therapy (PDT) in the treatment of the pigmented subtype of basal cell carcinoma (BCC) based on the current literature. PDT is a light-activated treatment, non-invasive, that selectively destroys tumor cells and tissues via the interaction of a photosensitizer, light, and molecular oxygen. It can induce cancer cell death through direct tumor vascular damage or via the induction of immune response. However, human skin is also an absorption and scattering medium since it contains hemoglobin and melanin that act as chromophores. Eumelanin can be considered a light-absorber and an intracellular antioxidant that can neutralize PDT-induced ROS and, therefore, decrease PDT success. Various factors, including tumor depth, the degree of pigmentation in malignant cells, and the individual's skin phototype, can impact the outcome of this intricate biochemical process. It has been widely recognized that PDT exhibits limited efficacy in the treatment of pigmented lesions. However, new combination techniques such as curettage or debulking before PDT show promising results in the treatment of pigmented BCC.
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Affiliation(s)
- Ewelina Mazur
- Department of Dermatology, Institute of Medical Sciences, Medical College of Rzeszow University, 35-055 Rzeszow, Poland (D.K.)
- Doctoral School, University of Rzeszow, 35-959 Rzeszow, Poland
| | - Dominika Kwiatkowska
- Department of Dermatology, Institute of Medical Sciences, Medical College of Rzeszow University, 35-055 Rzeszow, Poland (D.K.)
| | - Adam Reich
- Department of Dermatology, Institute of Medical Sciences, Medical College of Rzeszow University, 35-055 Rzeszow, Poland (D.K.)
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Wakamatsu K, Ito S. Recent Advances in Characterization of Melanin Pigments in Biological Samples. Int J Mol Sci 2023; 24:ijms24098305. [PMID: 37176019 PMCID: PMC10179066 DOI: 10.3390/ijms24098305] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 04/23/2023] [Accepted: 04/28/2023] [Indexed: 05/15/2023] Open
Abstract
The melanin pigments eumelanin (EM) and pheomelanin (PM), which are dark brown to black and yellow to reddish-brown, respectively, are widely found among vertebrates. They are produced in melanocytes in the epidermis, hair follicles, the choroid, the iris, the inner ear, and other tissues. The diversity of colors in animals is mainly caused by the quantity and quality of their melanin, such as by the ratios of EM versus PM. We have developed micro-analytical methods to simultaneously measure EM and PM and used these to study the biochemical and genetic fundamentals of pigmentation. The photoreactivity of melanin has become a major focus of research because of the postulated relevance of EM and PM for the risk of UVA-induced melanoma. Our biochemical methods have found application in many clinical studies on genetic conditions associated with alterations in pigmentation. Recently, besides chemical degradative methods, other methods have been developed for the characterization of melanin, and these are also discussed here.
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Affiliation(s)
- Kazumasa Wakamatsu
- Institute for Melanin Chemistry, Fujita Health University, Toyoake 470-192, Aichi, Japan
| | - Shosuke Ito
- Institute for Melanin Chemistry, Fujita Health University, Toyoake 470-192, Aichi, Japan
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Dooley TP, Anderson S, Ito S, Wakamatsu K. Cyclic oscillations in melanization within
Hystrix
porcupine quills. Pigment Cell Melanoma Res 2023; 36:321-324. [DOI: 10.1111/pcmr.13084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 03/13/2023] [Indexed: 04/03/2023]
Affiliation(s)
| | - Sydney Anderson
- Department of Mammalogy American Museum of Natural History New York New York USA
| | - Shosuke Ito
- Institute for Melanin Chemistry Fujita Health University Toyoake Japan
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Pena AM, Ito S, Bornschlögl T, Brizion S, Wakamatsu K, Del Bino S. Multiphoton FLIM Analyses of Native and UVA-Modified Synthetic Melanins. Int J Mol Sci 2023; 24:4517. [PMID: 36901948 PMCID: PMC10002570 DOI: 10.3390/ijms24054517] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/14/2023] [Accepted: 02/21/2023] [Indexed: 03/02/2023] Open
Abstract
To better understand the impact of solar light exposure on human skin, the chemical characterization of native melanins and their structural photo-modifications is of central interest. As the methods used today are invasive, we investigated the possibility of using multiphoton fluorescence lifetime (FLIM) imaging, along with phasor and bi-exponential fitting analyses, as a non-invasive alternative method for the chemical analysis of native and UVA-exposed melanins. We demonstrated that multiphoton FLIM allows the discrimination between native DHI, DHICA, Dopa eumelanins, pheomelanin, and mixed eu-/pheo-melanin polymers. We exposed melanin samples to high UVA doses to maximize their structural modifications. The UVA-induced oxidative, photo-degradation, and crosslinking changes were evidenced via an increase in fluorescence lifetimes along with a decrease in their relative contributions. Moreover, we introduced a new phasor parameter of a relative fraction of a UVA-modified species and provided evidence for its sensitivity in assessing the UVA effects. Globally, the fluorescence lifetime properties were modulated in a melanin-dependent and UVA dose-dependent manner, with the strongest modifications being observed for DHICA eumelanin and the weakest for pheomelanin. Multiphoton FLIM phasor and bi-exponential analyses hold promising perspectives for in vivo human skin mixed melanins characterization under UVA or other sunlight exposure conditions.
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Affiliation(s)
- Ana-Maria Pena
- L’Oréal Research and Innovation, 93601 Aulnay-sous-Bois, France
| | - Shosuke Ito
- Institute for Melanin Chemistry, Fujita Health University, Toyoake 470-1192, Japan
| | | | | | - Kazumasa Wakamatsu
- Institute for Melanin Chemistry, Fujita Health University, Toyoake 470-1192, Japan
| | - Sandra Del Bino
- L’Oréal Research and Innovation, 93601 Aulnay-sous-Bois, France
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