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How Melanocytes Improve the Efficacy of 3D Human Skin Models

Primarily located in the basal cell of the epidermis, melanocytes are a type of cell that produces melanin. Melanin, as you may know, is the brown pigment responsible for skin colouration and UV protection, but also has an impact on the skin’s immune response and protects the body from toxic chemicals and pollutants.

When it comes to testing cosmetics, wound care and other product ingredients on 3D human skin equivalent models such as Labskin, there’s no one size or colour that fits all skin types. That’s why the Labskin team, in collaboration with the University of Bradford are developing skin models containing melanocytes. By introducing donor cells from different ethnic backgrounds, a wider variety of tests can be performed on skin with different levels of pigmentation.

The function of melanocytes on the skin

Melanocytes, known for their ability to produce and distribute pigmentation, can be found in other areas of the body, such as hair follicles and irises of the eyes. Evidence has increasingly shown that not only are they melanin-producing cells but have several functions including:

  • UV protection
  • Natural immune response
  • Protection from toxic chemicals and pollutants
Melanocytes (green) transferring melanin to keratinocytes (red) in a tissue model

UV protection

Melanocytes produce two different types of melanin; eumelanin, which is dark brown in colour, and pheomelanin, which can have a red or yellow tint. Eumelanin has superior photoprotective properties compared to pheomelanin and provides a stronger barrier from UV-induced skin damage. As darker skin tones contain more eumelanin than fairer skin, the same skin care products can have different effects on various skin types.

Introducing melanocytes to skin test models when developing new cosmetic and sun protection factor (SPF) products can help explore UV exposure, skin damage, and beneficial effects more precisely. Therefore, the efficacy of each product can be certified to a greater degree, a more personalised approach to skin care can be offered, while marketing spend can niche down to a more targeted audience.

Melanocytes as part of a natural immune response

Several recent studies have shown that melanocytes are capable of sensing and responding to bacterial and viral infections. As the skin covers the body, it’s known to be the first line of defence against a range of pathogens such as arboviruses and bacteria. Since melanocytes have a large surface area, dendritic nature, and are strategically positioned in the superficial layers of the skin, it raises the possibility that they are immunologically important cells in the skin’s immune system. Especially when you note that certain skin infections are more common in fair skin, compared to those with darker skin.

With this information in hand, medical and cosmetic skincare companies that treat conditions such as eczema and psoriasis could benefit from a skin model that uses melanocytes in their skin model. This allows them to test the cellular and antimicrobial response of product ingredients on different skin tones while validating products with a more targeted outcome.

Protection from toxic chemicals and pollutants

There is a strong connection between the binding nature of melanocytes with toxic chemicals and melanomas. Various drugs and pollutants can bind to melanin and be retained for extended periods of time, such as:

  • Heavy metals
  • Organic amines
  • Polycyclic aromatic hydrocarbons

In the short term, melanin plays a role in protecting pigmented cells and adjacent tissues by adsorbing any harmful chemicals and pollutants. Over time, harmful substances can be slowly released at non-toxic levels. However, if the skin is exposed to high levels of noxious chemicals in the long-term, which are then stored on the melanin, degeneration and lesions can occur in the cells themselves, along with the surrounding tissues. Ultimately leading to malignant melanomas in a worst-case scenario.

If melanocytes were used to create 3D human skin models, the impact of certain product ingredients on various skin tones could be more deeply explored, especially for products that claim to have detoxifying properties that are designed to eliminate toxic chemicals and pollutants from the skin.

Continuous innovation in lab-grown, full-thickness human skin models

As the Greek philosopher, Heraclitus once wrote, “the only constant in life is change”, never has this been more apparent in the world of technology innovation. Labskin, offering the only commercially available lab-grown, human skin model that naturally mimics the skin’s microbiome, continues to innovate and explore new possibilities for testing skin care, cosmetics, health care, drug delivery, or wound care products.

By developing new 3D human skin models using melanocytes, Labskin will open up opportunities for global skin care companies to test and authenticate product ingredients on a wider range of skin tones and ethnicities.