Variations in skin composition causes psoriasis, atopic dermatitis: Study

About 845 million people suffer from skin conditions There are many different skin conditions that can be caused by ageing trauma environmental causes and genetics According to two recent UC Davis Health research psoriasis and atopic dermatitis may be caused by variations in skin composition Skin does not have a uniform composition throughout the body said Emanual Maverakis professor of dermatology molecular medical microbiology at UC Davis and senior author on both studies Different skin characteristics at different body sites may affect the skins susceptibility to certain diseasesBody site determines skin structure and function and disease susceptibilityThe skin is the largest organ in the body It has an average area of about 20 square feet thats the size of a 4 by 5 room Its outermost layer epidermis has a lipid matrix composed of free fatty acids cholesterol and ceramides a family of waxy lipid moleculesThis layer must meet the environmental challenges specific to each area of the body For example the skin of the face needs to be thin and flexible to accommodate facial expressions The skin covering the heel of the foot has to be thick and rigid to withstand force and protect it from objects we step onSkin composition depends on multiple factors including the structure of the skin barrier the cell types and the genes they expressUntil recently little was known about the cellular and molecular processes behind these differences In the first study researchers showed the mechanisms that lead to these structural changes in the skinThe epidermis has a brick and mortar structure molecules like ceramides cholesterol and fatty acids make up the mortar and cells called keratinocytes are the bricksThe researchers used singlecell sequencing to characterize how the keratinocytes differ at different body sites They also used targeted molecular profiling to characterize the molecules that form the mortar between the keratinocytes They then examined how these differences in gene expression matched the compositional differences in the lipid and protein structures across body sites These experiments explained why the skin looks so different at different body sitesThe compositional differences in the skins lipids and proteins across different body sites may also explain why different skin diseases are found at different body sites While characterizing the specific lipid alterations associated with various skin diseases the researchers discovered that lipids stuck to a piece of tape applied to the skin were sufficient to diagnose a patient with a particular skin diseaseThese discoveries will lead to nondiagnostic tests for common dermatologic disease said colead author Project Scientist Alexander MerleevThese differences are also relevant to the future design of skin care products said Stephanie Le dermatology resident and colead author of the study They demonstrate how skin care products should be specifically formulated to match the particular body site that they will be applied toPsoriasis and the immune systemIn the second study the research team studied how skin cells interact with the immune systemPreviously it was known that keratinocytes could secrete substances that both increase and decrease inflammation Using singlecell sequencing to analyze each keratinocyte individually the researchers observed that these immunemodulating molecules were expressed in certain layers of the epidermisKeratinocytes at the lowest layer of the epidermis secrete immuneattracting and immune antiinflammatory molecules This is to attract immune cells to the skin and park them in place to wait patiently to fight off any pathogenic microbe or parasite that might break through the physical barrier of the skin In contrast they found that the keratinocytes in the outer layer of the epidermis secrete proinflammatory molecules in particular IL36IL36 is a main mediator of a subtype of psoriasis an inflammatory skin disease The team found that the amount of IL36 in the skin was regulated by another molecule called PCSK9 and that individuals with variations in their PCSK9 gene were predisposed to developing psoriasisOur discovery that different layers of the skin secrete different immune mediators is an example of how the skin is highly specialized to interact with the immune system Some people develop skin diseases such as psoriasis when there is an imbalance in the molecules secreted by the different layers of the skin said UC Davis research fellow Antonio JiXu colead author of the studyAlso Read Everything you need to know about freezing your eggsThis story has been sourced from a third party syndicated feed agencies Midday accepts no responsibility or liability for its dependability trustworthiness reliability and data of the text Midday managementmiddaycom reserves the sole right to alter delete or remove without notice the content in its absolute discretion for any reason whatsoever