A Novel Method for Visualizing Melanosome and Melanin Distribution in Human Skin Tissues

Melanin incorporated into keratinocytes plays an important role in photoprotection; however, abnormal melanin accumulation causes hyperpigmentary disorders. To understand the mechanism behind the accumulation of excess melanin in the skin, it is essential to clarify the spatial distribution of melanosomes or melanin in the epidermis. Although several markers have been used to detect melanosomes or melanin, no suitable markers to determine the precise localization of melanin in the epidermis have been reported. In this study, we showed that melanocore-interacting Kif1c-tail (M-INK), a recently developed fluorescent probe for visualizing mature melanosomes, binds to purified melanin in vitro, and applied it for detecting melanin in human skin tissues. Frozen skin sections from different phototypes were co-stained for the hemagglutinin (HA)-tagged M-INK probe and markers of melanocytes or keratinocytes, and a wide distribution of melanin was observed in the epidermis. Analysis of the different skin phototypes indicated that the fluorescent signals of HA-M-INK correlated well with skin color. The reconstruction of three-dimensional images of epidermal sheets enabled us to observe the spatial distribution of melanin in the epidermis. Thus, the HA-M-INK probe is an ideal tool to individually visualize melanin (or melanosome) distribution in melanocytes and in keratinocytes in skin tissues.

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Cosmetic efficacy claims in vitro using a three-dimensional human skin model

International Journal of Cosmetic Science ◽

10.1046/j.1467-2494.2001.00098.x ◽

2001 ◽

Vol 23 (5) ◽

pp. 309-318 ◽

Cited By ~ 16

Author(s):

K. Schlotmann ◽

M. Kaeten ◽

A. F. Black ◽

O. Damour ◽

M. Waldmann-Laue ◽

...

Keyword(s):

Human Skin ◽

Three Dimensional ◽

Skin Model

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Probing Trace Elements in Human Tissues with Synchrotron Radiation

Crystals ◽

10.3390/cryst10010012 ◽

2019 ◽

Vol 10 (1) ◽

pp. 12 ◽

Cited By ~ 2

Author(s):

Mihai R. Gherase ◽

David E. B. Fleming

Keyword(s):

Trace Elements ◽

Spatial Distribution ◽

Synchrotron Radiation ◽

Research Effort ◽

Three Dimensional ◽

Human Tissues ◽

Chemical Affinity ◽

X Ray ◽

Current Research Effort

For the past several decades, synchrotron radiation has been extensively used to measure the spatial distribution and chemical affinity of elements found in trace concentrations (<few µg/g) in animal and human tissues. Intense and highly focused (lateral size of several micrometers) X-ray beams combined with small steps of photon energy tuning (2–3 eV) of synchrotron radiation allowed X-ray fluorescence (XRF) and X-ray absorption spectroscopy (XAS) techniques to nondestructively and simultaneously detect trace elements as well as identify their chemical affinity and speciation in situ, respectively. Although limited by measurement time and radiation damage to the tissue, these techniques are commonly used to obtain two-dimensional and three-dimensional maps of several elements at synchrotron facilities around the world. The spatial distribution and chemistry of the trace elements obtained is then correlated to the targeted anatomical structures and to the biological functions (normal or pathological). For example, synchrotron-based in vitro studies of various human tissues showed significant differences between the normal and pathological distributions of metallic trace elements such as iron, zinc, copper, and lead in relation to human diseases ranging from Parkinson’s disease and cancer to osteoporosis and osteoarthritis. Current research effort is aimed at not only measuring the abnormal elemental distributions associated with various diseases, but also indicate or discover possible biological mechanisms that could explain such observations. While a number of studies confirmed and strengthened previous knowledge, others revealed or suggested new possible roles of trace elements or provided a more accurate spatial distribution in relation to the underlying histology. This area of research is at the intersection of several current fundamental and applied scientific inquiries such as metabolomics, medicine, biochemistry, toxicology, food science, health physics, and environmental and public health.

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Assessment of the Ocular Irritancy Potential of Hair Conditioners in a Three-Dimensional in Vitro Human Skin Model

Journal of Toxicology Cutaneous and Ocular Toxicology ◽

10.3109/15569529409037518 ◽

1994 ◽

Vol 13 (2) ◽

pp. 117-125 ◽

Cited By ~ 1

Author(s):

T. Donnelly ◽

B. Decker ◽

M. Stemp ◽

L. A. Rheins ◽

P. Logemann

Keyword(s):

Human Skin ◽

Three Dimensional ◽

Skin Model

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Three-dimensional hydrogel scaffolds facilitate in vitro self-renewal of human skin-derived precursors

Acta Biomaterialia ◽

10.1016/j.actbio.2014.03.018 ◽

2014 ◽

Vol 10 (7) ◽

pp. 3177-3187 ◽

Cited By ~ 8

Author(s):

Xinyue Wang ◽

Shu Liu ◽

Qian Zhao ◽

Na Li ◽

Huishan Zhang ◽

...

Keyword(s):

Human Skin ◽

Three Dimensional ◽

Self Renewal ◽

Hydrogel Scaffolds

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Rapid formation of functional muscle in vitro using fibrin gels

Journal of Applied Physiology ◽

10.1152/japplphysiol.00273.2004 ◽

2005 ◽

Vol 98 (2) ◽

pp. 706-713 ◽

Cited By ~ 201

Author(s):

Yen-Chih Huang ◽

Robert G. Dennis ◽

Lisa Larkin ◽

Keith Baar

Keyword(s):

Physiological Function ◽

Three Dimensional ◽

Force Production ◽

Force Transducer ◽

Force Frequency ◽

Platinum Electrodes ◽

Fibrin Gel ◽

Novel Method

The transition of a muscle cell from a differentiated myotube into an adult myofiber is largely unstudied. This is primarily due to the difficulty of isolating specific developmental stimuli in vivo and the inability to maintain viable myotubes in culture for sufficient lengths of time. To address these limitations, a novel method for rapidly generating three-dimensional engineered muscles using fibrin gel casting has been developed. Myoblasts were seeded and differentiated on top of a fibrin gel. Cell-mediated contraction of the gel around artificial anchors placed 12 mm apart culminates 10 days after plating in a tubular structure of small myotubes (10-μm diameter) surrounded by a fibrin gel matrix. These tissues can be connected to a force transducer and electrically stimulated between parallel platinum electrodes to monitor physiological function. Three weeks after plating, the three-dimensional engineered muscle generated a maximum twitch force of 329 ± 26.3 μN and a maximal tetanic force of 805.8 ± 55 μN. The engineered muscles demonstrated normal physiological function including length-tension and force-frequency relationships. Treatment with IGF-I resulted in a 50% increase in force production, demonstrating that these muscles responded to hormonal interventions. Although the force production was maximal at 3 wk, constructs can be maintained in culture for up to 6 wk with no intervention. We conclude that fibrin-based gels provide a novel method to engineer three-dimensional functional muscle tissue and that these tissues may be used to model the development of skeletal muscle in vitro.

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A novel human pluripotent stem cell-based assay to predict developmental toxicity

Archives of Toxicology ◽

10.1007/s00204-020-02856-6 ◽

2020 ◽

Vol 94 (11) ◽

pp. 3831-3846

Author(s):

Karin Lauschke ◽

Anna Kjerstine Rosenmai ◽

Ina Meiser ◽

Julia Christiane Neubauer ◽

Katharina Schmidt ◽

...

Keyword(s):

Developmental Toxicity ◽

Three Dimensional ◽

Cell Types ◽

Microtiter Plate ◽

Embryoid Bodies ◽

The Body ◽

Chemically Induced ◽

Novel Method ◽

Induced Pluripotent

Abstract There is a great need for novel in vitro methods to predict human developmental toxicity to comply with the 3R principles and to improve human safety. Human-induced pluripotent stem cells (hiPSC) are ideal for the development of such methods, because they are easy to retrieve by conversion of adult somatic cells and can differentiate into most cell types of the body. Advanced three-dimensional (3D) cultures of these cells, so-called embryoid bodies (EBs), moreover mimic the early developing embryo. We took advantage of this to develop a novel human toxicity assay to predict chemically induced developmental toxicity, which we termed the PluriBeat assay. We employed three different hiPSC lines from male and female donors and a robust microtiter plate-based method to produce EBs. We differentiated the cells into cardiomyocytes and introduced a scoring system for a quantitative readout of the assay—cardiomyocyte contractions in the EBs observed on day 7. Finally, we tested the three compounds thalidomide (2.3–36 µM), valproic acid (25–300 µM), and epoxiconazole (1.3–20 µM) on beating and size of the EBs. We were able to detect the human-specific teratogenicity of thalidomide and found the rodent toxicant epoxiconazole as more potent than thalidomide in our assay. We conclude that the PluriBeat assay is a novel method for predicting chemicals’ adverse effects on embryonic development.

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Prediction of the layered ink layout for 3D printers considering a desired skin color and line spread function

Optical Review ◽

10.1007/s10043-021-00679-z ◽

2021 ◽

Author(s):

Kazuki Nagasawa ◽

Junki Yoshii ◽

Shoji Yamamoto ◽

Wataru Arai ◽

Satoshi Kaneko ◽

...

Keyword(s):

Human Skin ◽

Skin Color ◽

Three Dimensional ◽

Estimation Method ◽

Three Dimensional Printing ◽

Line Spread Function ◽

Spread Function ◽

3D Printers ◽

Dimensional Printing ◽

Line Spread

AbstractWe propose a layout estimation method for multi-layered ink using a measurement of the line spread function (LSF) and machine learning. The three-dimensional printing market for general consumers focuses on the reproduction of realistic appearance. In particular, for the reproduction of human skin, it is important to control translucency by adopting a multilayer structure. Traditionally, layer design has depended on the experience of designers. We, therefore, developed an efficient layout estimation to provide arbitrary skin color and translucency. In our method, we create multi-layered color patches of human skin and measure the LSF as a metric of translucency, and we employ a neural network trained with the data to estimate the layout. As an evaluation, we measured the LSF from the computer-graphics-created skin and fabricate skin using the estimated layout; evaluation with root-mean-square error showed that we can obtain color and translucency that are close to the target.

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