The main factors in the development of acne: sebum and the P. acnes strain

Researchers have long believed that Propionibacterium acnes causes acne . But these bacteria are found in abundance on everyone's skin, and yet not everyone has acne. Genetic sequencing recently revealed that not all P. acnes are the same—there are different strains, some of which are abundant in acne lesions and some of which are never found there.

However, acne research and therapeutic development have been hampered by the lack of an animal model that replicates the human condition. For example, when P. acnes is injected into mice, there is no long-term skin damage because the mouse's immune system quickly destroys the bacteria.

However, researchers at the University of California School of Medicine have developed a new mouse model that can reproduce human acne, allowing researchers to directly compare "good" (non-pathogenic) and "bad" (acne-related) strains of P. acnes bacteria.

In the article you can learn in detail about the decisive factors in the occurrence of acne.

The role of sebum in the development of acne

The team of researchers prepared synthetic sebum following a recipe they found in a previous scientific study. A simple mixture of four ingredients was used: fatty acids, triglycerides, waxes and squalene (a precursor compound to sterols such as cholesterol and steroid hormones), which add up to resemble human sebum.

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The researchers inoculated mice with P. acnes and applied synthetic sebum daily.

Without sebum, the mice had minimal breakouts and the bacteria died quickly. There were also no skin changes when using sebum alone.

But when the researchers applied both sebum and P. acnes, they saw true acne, with the bacteria surviving for several weeks. P. acnes strains also caused inflammation in the skin, as measured by increased levels of inflammatory molecules, called cytokines.

The role of the P. acnes strain in the development of acne

The researchers then tried to do the same with non-pathogenic strains of P. acnes. There were approximately twice as many lesions caused by acne-associated P. acnes strains as lesions caused by non-pathogenic strains.

Unlike humans, all the mice in these experiments were genetically identical.

This means that differences in the severity and number of acne lesions were caused only by differences between bacterial strains, and not by differences in the mice's innate ability to react to bacteria.

A promising direction of therapeutic tactics for acne eradication

The team hopes to identify genes that are unique to acne-associated strains of P. acnes and determine what it is in human sebum that allows these strains to spread.

What medications can cause drug-induced acne?

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This information could help the team better understand who is at increased risk for acne and how to develop personalized treatments and vaccines that target acne-promoting bacterial factors or sebum components.

Thank you for staying with Read other interesting articles in the “Dermatology” section. You may be interested in Vaccination against acne - a promising step into the future

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