New LC-MS/MS Study Finds Oral Barrier Has Similar Lipid Composition to Skin Barrier

Flat human skin | Image Credit: © PixieMe - stock.adobe.com

A recent study published in Cell Reports reveals new information about the composition of the oral permeability barrier, which protects the oral cavity from infection. The research, conducted by scientists at Hokkaido University in Sapporo, Japan, discovered that the lipid composition of the oral barrier is similar to that of the skin barrier.

In this study, liquid chromatography (LC)-tandem mass spectrometry (MS/MS) was used to perform detailed analyses of ceramides, including acylceramides and protein-bound ceramides, in the digestive tract. In addition, the role of acylceramides and protein-bound ceramides in oral barrier formation were analyzed.

The study identified the presence of two important lipid types, ω-O-acylceramides (acylceramides) and protein-bound ceramides, in the oral mucosae (buccal and tongue mucosae), esophagus, and stomach in mice. Acylceramides and protein-bound ceramides play a vital role in the formation of permeability barriers in the skin, but their role in the oral cavity was previously unknown.

Furthermore, the study found that the fatty acid elongase Elovl1 is involved in the synthesis of ceramides, including acylceramides and protein-bound ceramides, in the oral mucosae and esophagus. The researchers discovered that the conditional knockout of Elovl1 causes abnormal oral barrier morphology and increased pigment penetration into the mucosal epithelium of the tongue. Additionally, the Elovl1 deficiency results in enhanced aversive responses to capsaicin-containing water.

In humans, the researchers found acylceramides in the buccal and gingival mucosae and protein-bound ceramides in the gingival mucosa. These findings suggest that acylceramides and protein-bound ceramides are essential for the formation of the oral permeability barrier, which protects against bacterial and fungal infections.

The researchers believe that their findings could lead to new treatments for oral diseases. The discovery of the similarity in lipid composition between the oral and skin barriers could also have wider implications for dermatology and other medical fields. The study adds to our understanding of the complex biology of the oral cavity and highlights the importance of lipid composition in barrier function.

Reference

Sassa, T.; Kihara, A. Involvement of ω-O-acylceramides and proteinbound ceramides in oral permeability barrier formation. Cell Rep., 2023. DOI: https://doi.org/10.1016/j.celrep.2023.112363