The function of unique ceramides in dog skin cells revealed

Key points of the research

• The action of our proprietary ceramide, "Nano-Fermented Ceramide Plus," has also been elucidated in canine keratinocytes.
• This suggests an approach to enhance ceramide synthesis pathway gene expression in canine skin, leading to anti-inflammatory effects and improved barrier function.
• Evidence generation and expectations for clinical application of skin care interventions in veterinary medicine

Research Background

Figure 1: Conceptual diagram of the negative spiral in canine skin: "dryness → scratching → weakened barrier → inflammation → itching"

To date, scientific knowledge in the field of animal skin is still insufficient. Directly applying human knowledge to animals may not be appropriate due to differences in skin structure and function, including fur, and therefore, research specifically tailored to animals is needed.
On the other hand, in the treatment guidelines for atopic dermatitis in humans, skincare is considered fundamental to treatment and the prevention of inflammation relapse, and it has been shown that improving the skin barrier function through moisturizing contributes to suppressing inflammation relapse and exacerbation.
In dogs, too, a vicious cycle of itching, as shown in Figure 1, is known to form. This cycle contributes to the chronicity and recurrence of skin inflammation, so early intervention through skincare that maintains the skin barrier function is thought to help maintain skin health.
In this study, drawing on accumulated knowledge from human studies, we focused on the characteristics of canine skin and decided to comprehensively verify the effects of our proprietary ceramide, "Nano-Fermented Ceramide Plus," using canine keratinocytes.

result

Result 1: Increased expression of ceramide synthesis pathway genes was confirmed in canine keratinocytes (CPEK).

In an in vitro experiment aimed at comprehensively evaluating the effects of our proprietary ceramide, "Nano-Fermented Ceramide Plus," on canine keratinocytes (CPEK), we found that Nano-Fermented Ceramide Plus increases the gene expression of multiple ceramide synthesis-related enzymes. For reference, in human skin, as shown in Figure 2, many enzymes work in mainly two pathways to produce ceramide. In canine skin, the ceramide mixture also increases the gene expression of A (SPTLC1), B-1 (SMPD1), and B-2 (GBA2, GALC) among these enzymes, indicating that it activates multiple pathways and is considered beneficial for the production of various ceramides present in canine skin.

Figure 2: Changes in ceramide synthesis-related gene expression levels in canine keratinocytes and ceramide synthesis pathways and related enzymes in human skin.

Result 2: CPEK suggests improved barrier function.

In CPEK, treatment with nano-fermented ceramide plus after damaging cells resulted in a significant decrease in transepidermal water loss (TEWL) and a significant increase in transepithelial electrical resistance (TEER). Microscopic images also confirmed that it promoted CPEK recovery. This suggests that nano-fermented ceramide plus may contribute to the health of the skin barrier in dogs as well (Figure 3).

Figure 3: Changes in transepidermal water loss, transepithelial electrical resistance, and microscopic images of damaged cells in CPEK.

Result 3: Enhanced anti-inflammatory effect confirmed when used in combination with dipotassium glycyrrhizinate (DPG).

To investigate the anti-inflammatory effects of nano-fermented ceramide plus on immune cells, we examined inflammatory cytokine production (IL-6 and IL-8) using canine macrophage cell lines. Compared to the negative control group, a decrease in IL-6 and IL-8 production was observed in the groups treated with nano-fermented ceramide plus or DPG, and this inhibitory effect was further enhanced by mixing the two (Figure 4).

Figure 4: Suppression of inflammatory cytokine (IL-6, IL-8) production in canine macrophage cells.

Future outlook

This study confirmed that our proprietary ceramide, Nano-Fermented Ceramide Plus, which had previously been observed in humans, increases gene expression in the ceramide pathway and exhibits anti-inflammatory effects, in canine skin cells as well. This suggests that Nano-Fermented Ceramide Plus plays an important role in improving skin barrier function and suppressing inflammation in dogs.
Going forward, we will further explore the potential for clinical application in dogs, deepening our research while considering various factors such as breed differences and age differences. Through our skincare research, we aim to contribute to the health of animal skin based on scientific evidence and support a richer life for both humans and animals.

Terminology

*1: Our proprietary ceramide "Nano-fermented ceramide plus (CC)"
This raw material is made from plant-derived natural ceramides (dihydroxylignoceroylphytosphingosine and ceramide 6II) derived from the fermentation residue of soy sauce (white soy sauce) made from soybeans and wheat, and has been subjected to high-pressure nanotechnology processing to improve skin penetration.

*2: Canine keratinocytes (CPEK)
These are the main cells that make up the epidermis of canine skin, and they play an important role in barrier formation and protection from external stimuli.

*3: Transepidermal water loss (TEWL)
One indicator of skin barrier function. It refers to the amount of water that evaporates from the skin, and a higher value indicates a weakened skin barrier function.

*4: Transepithelial electrical resistance (TEER)
This index evaluates the adhesion between cells and the integrity of the skin barrier. It measures the electrical resistance when an electric current is passed through the cell layer; a higher value indicates better barrier function.

*5: Canine macrophage cell line
A cell line of macrophages derived from dogs. Macrophages are responsible for processing foreign substances and regulating inflammatory responses in the body.