Nourishing and preserving the skin’s natural barrier is essential to dermal health and longevity. The normal human epidermal keratinocyte, or NHEK, is the most significant cell type in the epidermis, comprising approximately 90% of the skin’s outer layer. Originating in the deepest layer of the epidermis, these cells progress up to the outermost layer composing the skin’s natural barrier. Thus, NHEK is vital to the integrity and health of the skin’s outermost layer, the stratum corneum. Here, we discuss the process and explain why stimulating NHEK differentiation is key to preserving this natural barrier, locking in moisture, and protecting the epidermis.
The life of the normal human epidermal keratinocyte
NHEK cells form in the foundations of the epidermis, the stratum basale. Here in the basal layer, they divide and proliferate, and begin to move up towards the skin’s outer layer, the stratum corneum. This process is referred to as differentiation, where the NHEK cells undergo gradual changes to their morphology. As they make their way towards the stratum corneum, they start producing various compounds and proteins that are vital to skin health, including keratin, cytokines, and growth factors.
Once they reach the stratum corneum, NHEK cells are found as flat, nucleus-free, keratin-rich squamous cells (Eckert and Rorke, 1989). Here, their high keratin content ‘cornifies’ the cell, creating the skin’s firm outer layer. These keratinocytes are highly sophisticated cells that play an integral role in forming a cohesive stratum corneum, and thus, the skin’s natural defenses. By forming a tight barrier with other cells, NHEKs prevent foreign bodies from permeating the epidermis, supporting the immune system while maintaining moisture.
Keratinocytes and skin hydration
As such, NHEK cells play an indispensable role in maintaining the skin’s natural defenses. Keratinocytes are critical to forming the skin’s natural barrier, promoting greater luminosity, flexibility, and smoothness, and of course, that highly coveted younger-looking appearance. The foundation of these benefits is hydration, within which NHEK differentiation plays an integral role. Keratinocytes build the skin’s barrier layer, locking in moisture and protecting the epidermis.
Consumers are well aware of the importance of hydration for overall skin health and longevity. For instance, a recent Mintel study found that of the 20,000 American adults surveyed, 72% of women used a facial moisturizer. This tendency is reflected in other markets; in China, 75% of women use a daily moisturizer and a further 64% also use a complimentary night cream. It’s also important for the industry to note that the demand for moisturizing products is also growing in the male grooming space. Currently, 27% of American men and 39% of British men use a daily moisturizing product.
Stimulating NHEK differentiation for rich, nourishing hydration
Although the concept of NHEK differentiation may not be common parlance on beauty product labels, this process is integral to the efficacy of these products. By supporting the differentiation process and nourishing these cells, products protect and improve the skin’s natural barrier. Through stimulating this process, moisturizing products can substantiate their claims and provide richer, more potent moisturization. Actives like Provital’s Aquaxtrem™ have been developed with NHEK cells in mind, activating the differentiation process to tighten the stratum corneum’s cell structure. Learn more about this innovative active here.