Dr. Thomas Hitchcock discusses the protective role certain strains of Cutibacterium acnes play in balancing the skin biome and harnessing that knowledge to formulate new skincare technology.
Thomas Hitchcock, PhD, Chief Science Officer, Crown Laboratories, and Adjunct Faculty, East Tennessee State University, Johnson City, TN.
“…we made this huge assumption for many decades, that all bacteria within a species have the same effect, such as C. acnes causes acne; Staph aureus causes dermatitis; Staph epidermidis is a skin commensal. But it’s not that simple,” said Thomas Hitchcock, PhD, who participated on the Panel “Viewpoints from Formulation Chemists and Industry Insiders” at this year’s Science of Skincare Summit in Austin, Texas.
“We’ve now found that just because something may be protective, if you put it in the wrong environment, it actually can become pathogenic. And so when we looked at C. acnes back in 2012, Dr. Huiying Li at UCLA…published a paper1 that really opened my eyes to the importance of C. acnes as a species. [It] is the most important skin microbe in my opinion.”
According to Dr. Hitchcock, C. acnes has until recently been thought to be a pathogen, but the bacteria has 1000s of strains and plays a much more complex role within the skin biome.
“What we’ve shown over the last decade in our own research2 is there’s a plethora of benefits to the right strains of C. acnes. …we know that everybody on the face of the earth has C. acnes as a species on their skin. It’s actually the most predominant microbe, at least bacterially, on the skin. Yet we know also that certain strains do have higher affinity to a pathogenic state versus a healthy state.”
To find a way to curate that beneficial strain, Dr. Hitchcock founded Xycrobe Therapeutics in 2013. The company was acquired by Crown Laboratories in May 2019.
“We were taking cytokine genes and putting them into the microbes to basically act like little medicine factories to produce biologics.”
The Xycrobe research group examined the use of those genetically modified microbes vs microbes alone in both animal and human trials for the treatment of psoriasis.
“When exploring this, the wild type strain wasn’t reducing inflammatory markers as robustly as the modified strain, but we saw significant benefits with both and that’s when we started peeling back these layers…”
According to Dr. Hitchcock, those layers revealed that the propionic acid in C. acnes stops malassezia from proliferating, is a tyrosinase inhibitor, prevents S. aureus from making biofilms, and reduces the pH of skin.
“And now we’re finding that…certain strains of Staph epidermidis produce high amounts of a protease that causes things like atopic dermatitis. And C. acnes actually lowers the pH. That makes that protease less active, and it keeps Staph epidermidis and Staph aureus in check.”
Even the control group, which was treated with only the wild type C. acnes strain, experienced significant reductions in inflammation, he said.
“And that inspired me because I started thinking, well, we think of microbes as inferior organisms, yet they’re able to do things that we cannot do. And that got me learning a little bit more about the symbiosis between microbes in the human body and other organisms.”
Microbes Wield Power
Although unseen by the naked eye, microbes are a permanent part of the skin’s ecosystem, said Dr. Hitchcock. When skin microbes are in balance, skin is healthier and less prone to disease.
“One of the things that I keep telling people is, yes, in science, we’ve been able to tease apart some of these molecules that are very beneficial in a petri dish.”
However, in real life there are billions of microbes on the skin, he said.
“…every second of every day, those microbes are spitting something out… What they spit out is based on how you treat them, whether they’re happy or whether they’re not happy.”
In other words, healthy skin has happy microbes that help to keep the biome in balance. The opposite is also true.
“And so it’s not so simple and in dermatology, especially in [benchtop] research… We made this huge assumption for many decades that all bacteria within a species have the same effect. In reality, the benefits or detriments imparted by bacteria is very strain specific.”
Striving for Symbiosis
A balanced skin biome leads to improvements in inflammation, edema, redness, and pigmentation, and only a skin-native microbe can help to achieve this balance, said Dr. Hitchcock.
“Since C. acnes is the main constituent of the microbiome of the skin, if you curate the right strain and provide the right environment for that strain to function, what we’ve shown is you can help achieve better symbiosis.”2
That strain for Dr. Hitchcock and his team is XYCM42, which is derived from C. acnes subspecies defendens.
“C. acnes produces huge amounts of antioxidants. (And this is all not just opinion. This is stuff that is well documented and published on.) And these antioxidants make you wonder, ‘Have we been hurting ourselves by washing ourselves so much?’ because the antioxidants protect us from UV radiation and such.”
According to Dr. Hitchcock, there are tribes in Central America that are isolated from Western civilization who don’t experience the same skin diseases, including skin cancer, acne, psoriasis, and atopic dermatitis.
“We are trying to sterilize ourselves, and it is hurting us. And that’s what the technology is about. It’s about achieving some of these goals for symbiosis in a legitimately scientifically proven way.”
What Dr. Hitchcock and his team have developed isn’t skin care, he said. It’s skin “biome” care.
“…and there’s a reason for that. Everybody I’ve talked to about it gets it. It’s just that they hadn’t heard this before positioned this way. I think the world’s ready for skin biome care.”
References
- Tomida S, Nguyen L, Chiu BH, Liu J, Sodergren E, Weinstock GM, Li H. Pan-genome and comparative genome analyses of propionibacterium acnes reveal its genomic diversity in the healthy and diseased human skin microbiome. mBio. 2013 Apr 30;4(3):e00003-13. doi: 10.1128/mBio.00003-13. PMID: 23631911; PMCID: PMC3663185.
- Rhee MS, Alqam ML, Jones BC, Phadungpojna S, Day D, Hitchcock TM. Characterization of a live Cutibacterium acnes subspecies defendens strain XYCM42 and clinical assessment as a topical regimen for general skin health and cosmesis. J Cosmet Dermatol. 2023 Mar;22(3):1031-1045. doi: 10.1111/jocd.15510. Epub 2022 Nov 14. PMID: 36374551.
Additional Reading:
Day D, Hitchcock TM. Rebooting the Biome: How Properly Caring for Your Skin Biome Can Do More for Your Health and Beauty Than Any Skincare Ingredient on the Market. Prominence Publishing; 2023.
