Two new studies have demonstrated how skin develops differently in various body regions, including the face, underarms, palms of our hands, and feet. Researchers discovered that differences directly influence the development of numerous skin illnesses across the body by profiling the changes in the skin.

Numerous skin diseases can be brought on by aging, trauma, environmental causes, and genetics. Skin function, structure, and disease susceptibility depend on the body site. The structure of the epidermis can be compared to that of a "brick and mortar" construction. Keratinocyte cells are the "bricks," whereas substances like ceramides, cholesterol, and fatty acids make up the "mortar."

The first study examined how the keratinocytes differed at various bodily areas using single-cell sequencing. Using targeted molecular profiling, they also studied the chemicals that serve as the "mortar" between the keratinocytes. They next looked at how the compositional variations in the lipid and protein structures across various body regions corresponded to these variances in gene expression. 

These studies explained why the skin appears differently on various body parts and can pave a new way towards developing non-diagnostic testing for common dermatologic diseases.

The second study focused on the relationship between skin cells and the immune system. The researchers discovered that these immune-modulating molecules were expressed in particular layers of the epidermis using single-cell sequencing to examine each keratinocyte individually.

The researchers found that the keratinocytes in the outer layer of the epidermis secrete pro-inflammatory chemicals, namely IL-36, which is a key mediator of a particular subtype of the inflammatory skin condition psoriasis. The team discovered that a different molecule called PCSK9 controlled the quantity of IL-36 in the skin and that people with abnormalities in their PCSK9 gene were more likely to develop psoriasis.  (The Print, 24 September, 2022)

https://theprint.in/health/studies-show-how-skin-diseases-form-differently-across-the-body/1140878/