Yet all current eczema treatments ignore the microbiome. Furthermore, almost every current treatment, like topical steroid creams or lotions are time-intensive and must be applied to the skin at least once a day. Other effective treatments such as the Dupixent, which is injected twice per month, requires fewer applications but is extremely expensive. Our team at the National Institutes of Allergy and Infectious Diseases decided to develop a different approach, with the skin microbiome in mind.
We suspected that having the “wrong” kind of Gram-negative bacteria on the skin could lead to eczema. To test the hypothesis we used one particular strain of Gram-negative bacteria, Roseomonas mucosa, collected from the skin of healthy people, to see whether this microbe would calm irritated skin.
Good versus bad bacteria
In humans, R. mucosa boosted the immune system in human skin cells. In contrast, when R. mucosa was collected from people with atopic dermatitis and tested in the same manner, it had no impact or made the eczema worse. This suggests that replacing “bad” strains of R. mucosa with “good” ones might be the key to treating patients.
What distinguishes the “bad” strains of R. mucosa from the bad? That’s a tricky question. To date we have learned that “bad” strains of R. mucosa produce skin irritants — specifically the histamine relative, histidinol, and monomethylgluterate. In contrast, the “good” bacteria make fatty molecules, lipids, that are known to protect the skin from dryness and S. aureus. It appears that the “good” and bad” the strains differ due to subtle changes in their DNA, but more research is needed.
What we do know is that it appears that all the R. mucosa found on healthy people is the “good” kind, while all the R. mucosa on eczema patients is “bad.” While some of the molecular details separating R. mucosa strains are unclear, our results gave us enough actionable information to design an early stage clinical trial to assess the safety and efficacy of applying a mix of three live R. mucosa strains collected from the skin of healthy volunteers and proven to be “good.”
This was the first study to ever evaluate if directly treating the bacteria on the skin could improve skin disease.
Just like in adults, no one suffered ill effects and most saw their eczema improve. These kids then reduced the number of days they needed to use topical creams. The bacteria treatment also reduced the population of S. aureus.
Seeing such profound results left me with a mixture of emotions. On one hand, it was extremely gratifying to hear patients and parents relay how much better they or their children felt and to see such amazing differences in both their skin and disposition after treatment.
However, no one on our team, myself included, could feel fully satisfied seeing the disappointment in the patients for whom the treatments failed. Every volunteer expressed enjoyment in participating in the study, learning about their disease, and contributing the medical knowledge. However, anything less than 100 percent improvement in 100 percent of patients suggests we still have more work to do.
Probiotics for the skin?
By using this approach, we hope to offer a way to reduce symptoms and the need for daily treatment — at a reasonable cost. If the good bacteria are capable of colonizing the skin and making it their home, then there is a chance that these microbes could provide long-term benefits long after active treatment stops.
Ian Myles is an assistant clinical investigator at the National Institute of Allergy and Infectious Diseases.
News credit : Cnn