Successful Construction of a Next-Generation Artificial Skin Model with Blood Vessels Possessing Cellular Diversity - Inventing a New Anti-Aging Care Theory Focused on How Cellular Diversity Creates Skin Elasticity

Rohto Pharmaceutical Co., Ltd. (Headquarters: Osaka City, President: Hidetoshi Segi), in a joint research effort with Professor Tatsuya Shimizu of the Institute of Advanced Biomedical Engineering and Science at Tokyo Women's Medical University, has constructed a next-generation artificial skin with blood vessels that autonomously reproduces the complex "cellular diversity" found in living skin. This model successfully cultivates populations of fibroblasts and pericyte-like cells, which are characteristic of living skin but difficult to maintain with conventional culture methods, achieving skin barrier function and elasticity close to that of living tissue. Furthermore, it has partially clarified the mechanism by which Vitamin C improves signs of skin aging via cells surrounding blood vessels. This achievement is expected to accelerate the development of next-generation skincare products and pharmaceuticals as an ethical and high-precision evaluation system to replace animal testing. The results of this research were published in the online scientific journal "EMBO Reports" on April 1st.

Figure 1. An artificial skin that highly reproduces the diversity and function of human dermal mesenchymal cells was developed by incorporating blood vessels.

1. Key Points of the Research

◆ Developed an artificial skin that reproduces the diversity of dermal cells similar to living tissue through co-culture with vascular endothelial cells.

◆ Discovered that the creation of cellular diversity improves the skin's barrier function and elasticity.

◆ Found that in skin with cellular diversity, the effects of Vitamin C in improving skin barrier function and elasticity are enhanced.

2. Research Background

Skin-composing cells have been broadly classified by their shape and function, such as epidermal keratinocytes and dermal fibroblasts. In recent years, with the development of technologies like single-cell gene expression analysis, it has become clear that even within the same classified cell type, individual cells have differences in function and properties that could be called individuality. Interestingly, it has been revealed that the individuality of dermal mesenchymal cells is lost with aging, and this is beginning to be considered an important factor in skin aging and diseases. However, with conventional cell culture technology, it was difficult to reproduce and analyze this cellular diversity, making it challenging to prove its connection to aging or to construct a care theory. Furthermore, with the global trend of reducing animal experiments, there is a demand for advanced alternative testing methods that can mimic the complexity of living organisms.

Therefore, in this research, we hypothesized that blood vessels play a crucial role in maintaining cellular diversity and began constructing an artificial skin model that reproduces human cellular diversity by creating an artificial skin with attached blood vessels. Furthermore, by comparing artificial skin with and without blood vessels, we investigated how cellular diversity supported by blood vessels affects the skin.

3. Results

・Construction of an artificial skin that reproduces the diversity of dermal mesenchymal cells by introducing vascular endothelial cells.

A typical artificial skin is a two-layer model consisting of two types of cells: epidermal keratinocytes and dermal fibroblasts. First, the research team constructed an artificial skin model with a vascular structure using three types of cells: epidermal keratinocytes, dermal fibroblasts, and umbilical cord-derived vascular endothelial cells (Figure 1). Next, they performed single-cell RNA sequencing analysis on the cells contained in the constructed artificial skin to evaluate the properties and diversity of the cells in the dermis. The dermis of living human skin contains diverse fibroblasts and vascular pericytes, but this diversity was lost in cells cultured two-dimensionally for research. On the other hand, it was confirmed that the diversity distribution pattern of fibroblasts and vascular pericytes in the constructed artificial skin was very similar to that of living human skin (Figure 2). This result indicates that a three-dimensional environment and cell-cell interactions between blood vessels and skin play a crucial role in reproducing the cellular heterogeneity of fibroblasts and vascular pericytes, which was conventionally difficult.

Figure 2. Comparison of dermal mesenchymal cell diversity in human skin and artificial skin by single-cell RNA sequencing.

・Improvement of skin barrier function and dermal elasticity by introducing vascular endothelial cells.

Next, we compared the functionality of artificial skin with and without blood vessels. The results showed improvements in the turnover function, which plays an important role in the skin's moisture barrier function and clarity, and in skin elasticity, which is related to wrinkles and sagging, due to the addition of blood vessels (Figure 3).

Figure 3. Functional changes in the artificial skin model due to the introduction of blood vessels.

・The turnover-improving and skin elasticity-improving effects of Vitamin C are enhanced in artificial skin with blood vessels.

Furthermore, we compared the reactivity of artificial skin to Vitamin C with and without blood vessels. The results confirmed that the usefulness of Vitamin C was enhanced by the addition of blood vessels in terms of turnover function, which plays an important role in the skin's moisture barrier function and clarity, and in skin elasticity, which is related to wrinkles and sagging (Figure 4).

Figure 4. Artificial skin model with introduced blood vessels

4. Future Outlook

This study revealed that the presence of vascular endothelial cells induces fibroblast diversity, which plays a decisive role in maintaining skin structure and function, as well as responsiveness to drugs. This research suggests the existence of a mechanism by which skin aging and diseases are controlled by the development and regression of blood vessels, and it supports a new skincare theory focused on blood vessels.

Furthermore, since the developed artificial skin model exhibits physiological responses closer to human skin than conventional models, we believe it can be a powerful tool to replace animal testing in the search for highly functional skincare ingredients, such as those for improving wrinkles and sagging, and in the safety and efficacy evaluation of pharmaceuticals.

Paper Information

<Title>

The heterogeneity of dermal mesenchymal cells reproduced in skin equivalents regulates barrier function and elasticity

<Author(s)>

Shun Kimura, Sachiko Sekiya, Sawa Yamashiro, Tetsutaro Kikuchi, Masatoshi Haga, & Tatsuya Shimizu

<Journal>

EMBO Reports

<DOI>

https://doi.org/10.1038/s44319-026-00757-w

Terminology

※1 Single-cell RNA sequencing

A method that uses a next-generation sequencer to comprehensively examine the entire mRNA content, i.e., the entire gene expression profile, within individual cells. General RNA sequencing extracts mRNA from all cells in a sample to investigate gene expression levels, so it only provides the averaged gene expression of the cell population. With single-cell sequencing, it is possible to investigate the differences in individual gene expression, which can be called the individuality of cells. Using this technology, it has been discovered that some cell populations within seemingly homogeneous cell types are useful for controlling various biological phenomena.

※2 Immunohistochemical analysis method

A method for staining and visualizing a target protein in a tissue by using an antibody that can bind to a specific protein. In this study, we used antibodies against proteins such as type I collagen, the main component of the dermis; CD31, which is characteristically present in vascular endothelial cells; and Ki67, which is present in proliferating epidermal keratinocytes during turnover, to investigate changes in tissue condition and skin function.