Microbiome Medics

Skin Deep: The Microbiome's Role in Healthy Skin

• Konijn Podcasts • Season 1 • Episode 20

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In this episode of Microbiome Medics Podcast, I (Dr. Sheena Fraser) speak with Dr. Holly Wilkinson, a microbiome scientist at Hull York Medical School, about the vital role of the skin microbiome in health and disease. We discuss how the skin microbiome’s unique characteristics, influenced by factors like body location and hygiene, are crucial for maintaining skin health. Dr. Wilkinson explains the relationship between the skin barrier and microbiota and the implications for conditions like acne and eczema.

We also explore natural skincare options, the research on probiotics for wound healing, and her current studies on chronic wounds, emphasising microbiome composition as a predictor for healing outcomes. This engaging conversation underscores the importance of a holistic approach to skincare and the need for more awareness of microbiome science in clinical practice.

This podcast is brought to you in collaboration with the British Society of Lifestyle Medicine.

Disclaimer:
The content in this podcast is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your doctor or qualified healthcare provider. Never disregard professional medical advice or delay in seeking it because of something you have heard on this podcast.

Intro:

Hello and welcome to the Microbiome Medics Podcast. I'm Dr. Siobhan McCormack. And I'm Dr. Sheena Fraser, and we're your co-hosts. We are both GPs and lifestyle medics with a shared passion for microbiome science, and we have spent the last five years deep diving into the world of the gut microbiome. We'll be translating the evidence and packaging it into actionable, bite-sized chunks so that you could harness the power of the microbiome to improve your own health and that of your patients. Just before we start this interview, we'd like to remind our listeners to take a look at the Gut Microbiome for Clinicians course. It's available through bslm.org.uk. It's a comprehensive course on the gut microbiome, which takes you from the basics to the clinical application of this fascinating new area of medicine. This course will empower you to use microbiome science in your daily practice. is.

Sheena:

Hello and welcome to another episode of the Microbiomedics podcast. I'm Dr. Sheena Fraser and in today's episode I'm joined by Dr. Holly Wilkinson. She's a microbiome scientist and a senior lecturer at Hull York Medical School with a PhD in the field of skin and wound healing and she's going to talk to us today about the importance of the skin microbiome in health and disease. So hello Holly.

Guest:

Hi Sheena, it's lovely to be here. Thank you for inviting me on the podcast.

Sheena:

No problem it's so lovely to have you here because we haven't really covered the skin so far and actually skin is quite a passion of mine because after I finished my GP training I went back to hospital medicine for a little while and I did a six-month post in dermatology because I realized that about 20% of the work we we see in general practice is actually dermatological and and prior to that hadn't really had any good dermatology training um so I did six months in dermatology and actually loved it I started doing minor surgery um and I brought my skills back to general practice I did another nine months of clinical assistant work in dermatology, And I've used my skills in general practice ever since. And I've always had that interest in dermatology. So when I started looking into the microbiome and what the skin microbiome is like, as well as the gut microbiome, I realized that this had a lot of influence in the way we should be considering how we treat the skin and how we do things. So I'd really like to hear your perspective on this. So before we start, perhaps you could talk about where you've come from and how you got into the skin microbiome, just so you can set the scene for us.

Guest:

Yes, well, I actually began my career in a very different area of science. So I was working originally in the field of evolutionary biology, and then I ended up taking quite a serendipitous path to my current area of research. So I was lucky enough to be offered a job around kind of 10, 15 years ago when I was working at the university as a laboratory technician. And here I worked on a collaborative project with an industry partner initially, where we were testing antimicrobial wound dressings. So this was my first experience of the world of bacteria and wounds and infection. And at the time, it was all about kind of developing the most potent treatments possible to kill all bacteria. We saw all bacteria as being bad, and it took a while for us to be able to shift that mindset and start to understand that we have this living microbial ecosystem that generally lives in harmony with our skin. So then kind of following this work, I obviously became very interested in the skin so during my PhD I learned more around the fundamental biology of the skin and I focused on research understanding how the skin repairs itself following injury and also finding out key mechanisms to explain why wound healing is impaired in the elderly and diabetic and now we're only just you know beginning to appreciate that the microbiome is a key mechanism in this which which we'll obviously talk about in more detail later. And then finally, when I became an academic around four years ago, this is really where I... Brought together all of my research experience and started to understand how the microbiome is linked to skin ageing, wound healing and various other kinds of cutaneous pathologies.

Sheena:

Excellent that's really really interesting. So before we get into all the depths of your research could you just talk us through what the skin microbiome is because Shiva and I are always talking about the gut microbiome and you know that you've gone into lots of depth into that over the last year but but I think you know the skin microbiome we haven't really touched upon and and can you explain to the listeners what it is and how it differs from the the gut microbiome and and really what makes it so important?

Guest:

Yeah so the skin is quite a unique area compared to other areas of the body such as the gut in that it is obviously externally facing and it's an incredibly harsh environment for microbes to live in because obviously if it wasn't then we would be exposed to infections constantly and it's also a very challenging area to research because there is much lower microbial mass in the skin than there is in the gut so we have to use very very sophisticated sequencing techniques to be able to identify the microbes in the skin and also understand what they're doing. And skin is harsh for microbes because it is highly acidic and the food sources there are very limited, you know, relative to the gut. So the microbes that live on our skin really have to be very highly adapted to the environment. And the way that the skin microbiome is made up in everybody is that we generally have what is called a core microbiome. So this is dominated by major types of bacteria, such as Staphylococcus. Carinibacteria, and Cutibacterium. And these core skin microbiota don't really change all that much between individuals. They're relatively stable as well. So they can deal with small fluctuations due to the environment. But then everyone also has what we call a transient microbiome as well. So these are bacteria that kind of, they come in, they hang around for a small while and then they, you know, they disappear again. And this includes microbes that we would consider to be pathogenic or opportunistic. So they're coming in, looking for opportunities, realising that there aren't opportunities and then leaving again. But what's particularly interesting about the skin is that the proportions of different types of bacteria really depend on body site location which correlates with the environmental conditions of those different body sites so the proportions of bacteria that you have on your face will be different to the proportions that you have on your feet as an example and what we tend to see is if you look at cutibacterium that's really a very lipid loving bacteria so that'll be in areas of your body where you have lots of sebaceous glands and sebum such as the face the upper back the chest and you know when we're thinking about acne they're they're obviously the areas that are very oily and they're where the areas where you're going to find a lot of cutibacterium and then areas that are very moist such as the armpit are dominated by bacteria such as staphylococcus and carini bacteria because this is where those bacteria are adapted to be using the substrates that are in the moist environments such as the salt and the sweat. Now, I think when we think about what a healthy microbiome is, this is quite challenging. And I don't think that there is a defining definition to say this is what a healthy microbiome is. Everyone is different. We all live in different biogeographical locations. We use different skincare products. We have different hygiene practices. But I think there are generally a few factors that are true regardless of the situation. So one of those is that the core skin microbiota is relatively stable, which I mentioned earlier. It returns to its normal state. You know, after you wash your hands, it depletes the microbiome, but that comes back quite rapidly. And number two is usually that if you have an issue in the microbiome, that is usually because there is some kind of perturbation in the skin already so this could be that there are changes in the hydration texture or pH of the skin. Which could be caused by ageing or skin pathology, or it could also be a situation where you have a breach to the skin barrier. So again, this could be linked to a skin condition like acne or eczema, or it could be because of a physical injury to the skin. I think the key message here is that if you want to really maintain a healthy skin microbiome, then you need to maintain good skin health. But likewise, if you have a perturbed microbiome or what we call microbial dysbiosis, then this could also be driving or contributing to exacerbating an existing skin condition.

Sheena:

Okay so we when we talk about the gut microbiome we we quite often talk about the the gut wall and the barrier there and how important that wall is in terms of the development of disease and everything and obviously the skin microbiome you know has a has a barrier and that obviously isn't microbial but very very important as part of the um the story of the the skin microbiome so can you can you talk about the skin barrier and and how that differs to say the gut um wall and and you know how that uh is it dynamic the way the gut wall is or is it something that you know is fairly static and always keeps everything out and you know what happens to that um over time Yeah.

Guest:

So the main difference is obviously we're looking at dry versus wet epithelia because the gut is kind of a wet epithelia, whereas the skin is a very dry epithelium. And the top layer of the skin, what we consider to be the skin barrier, is actually a layer of dead cells. So they're not viable. And it's kind of a brick and mortar kind of structure. So we have all of our dead corneocytes. And in between all of those dead corneocytes are lipids that kind of help glue everything together like a cement so it really acts like a physical strong barrier against the external environment and the dynamic component of it really is the underlying cells in the epidermis the keratinocytes because their role is to constantly replenish that barrier so they're constantly proliferating and differentiating up through the skin to replace those shedding dead corneocytes In terms of kind of the links between the crosstalk between the microbiome and the skin barrier, most of that is regulated by the immune cells that live in the skin. So they act as sentinels and they're kind of always patrolling and looking for any problems with the skin barrier. But it is also regulated by the keratinocytes themselves. So the epidermal cells can also sense and respond to the bacteria there. But I would say that generally, generally, The dynamic component of the skin is less so the homeostasis and more so if there is something like a breach to the barrier. So that's where kind of all the reprogramming mechanisms are put into place and the ability of the skin to regenerate and activate. That's when all of that happens.

Sheena:

And so how much are the microbiota in the skin, the microorganisms, how much are they playing a role in that barrier?

Guest:

So the way that the microbiota the general microbiota that we're kind of thinking of as the commensal microbiota that are really you know good for the skin and kind of help to maintain the skin barrier there are a few things that those microbiota can do so one is that they already exist in the environment so it's very hard then for a pathogen to come in and gain a foothold because they act as a as a kind of a physical barrier that they're competing with pathogens for food sources that they're highly adapted to being able to take away from the pathogens so they can prevent colonization with pathogens by just their presence but then also the different commensal bacteria can also produce factors that really help the skin for example cutibacterium which we find in those sebaceous sites it's obviously a lipid loving bacteria and it breaks down lipids, but it can also signal to keratinocytes to make them produce more lipids. So it's really important for hydration of the skin, as an example. And that hydration of the skin is also, again, important to prevent pathogens from invading because it maintains that skin barrier as part of that cement and that brick and mortar structure. They can also, the commensal bacteria can also produce antimicrobials themselves so when we think about antimicrobials we tend to think about things that we're putting on the skin to prevent pathogens from growing but the natural bacteria that live on our skin also produce factors that can kill pathogens so cutie bacteria staphylococcus they've all been shown to produce things that can actually prevent pathogens like staphylococcus aureus the bacteria we associate with MRSA from being able to colonize the skin so they play a wide range of roles really in preventing that pathogen colonization and kind of maintaining that skin barrier yeah.

Sheena:

And and what about because a friend of mine who's a, herbalist would tell me that you know you shouldn't put anything on your skin that you're not prepared to eat um because of course the skin um does allow a certain amount of substances to to be absorbed. How is that regulated by skin bacteria?

Guest:

So in terms of kind of skincare, the skin bacteria can actually utilize some of the products that we find in skincare. So for example, ceramides are obviously a huge component of modern day skincare. So bacteria can utilize those substrates and then that helps them to produce more lipids. So when we're putting ceramides on our skin, not only are the ceramides having a direct positive influence on maintaining moisturization of our skin, but our commensal bacteria can utilize the ceramides themselves as a nutrient source. There's also been studies to show that hyaluronic acid, another example of a humectant that obviously helps to maintain hydration of the skin, has a positive effect on the microbiome. So it can actually reduce pathogens on the skin like Staphylococcus aureus and promote kind of diversity of the skin microbiome. So I think when we're thinking about what we're putting on our skin, I think we do need to kind of consider the effects that those products are having on the skin microbiome as well because obviously they will have a direct effect on our skin but we also need to consider their effects on the skin microbiome and I think we need to start to shift thinking a little bit because the way that we think about the skin and the microbiome is we think of them as two separate entities when actually when we talk about skin we should automatically think of the microbiome as being a component of the skin.

Sheena:

Yeah, no, I agree. And I think this has kind of been the missing link with a lot of, when we think about a lot of disease processes in general, we're thinking, pathophysiology, we're thinking biochemistry, you know, all these things, all these processes that are happening, but we're not considering, you know, how the bacterial population or the viral population or, you know, all the other microorganisms that are in the vicinity, how they're influencing that physiology. And I think that's key. So what's really interesting for me is I was reading a book and it was talking about Amazonian tribes. And there was a microbiome scientist that went out to actually live with the Amazonian tribes and study them. And one thing that they noticed was that their skin was perfect. They didn't have a lot of skin diseases the way we have in the West. So, you know, things like eczema, psoriasis, sacne, these weren't things that they suffered from. And their skin, it didn't require a lot of care. So, you know, the Amazonian tribes are not putting a lot of creams and potions and lotions on their skin. They're washing in local streams and they're not applying any moisturizer or anything like that to their skin. Um and and the the book that i was i was reading was talking about how the population of bacteria was much more diverse and much richer on the skin of the amazonian tribes um and they had bacteria that um we don't have in the west on their skin and bacteria for example that can eat the um the ammonia when we sweat that can take away the sort of sweaty smell from us. And the poor scientist from the West was belittled by them over there because he was very smelly in comparison to their population. But I found that really, really interesting. So how has our microbiome formed and developed? And how have we gone so far from that original hunter-gatherer microbiome to what we have now in the West?

Guest:

Yes, so I think I'll begin by answering the question about the development of the microbiome and then come back to the Amazonian research because it is very interesting. So the way that our microbiome develops is that it is seeded at birth. So once we are delivered through the birth canal, our initial skin bacteria is actually vaginal bacteria from our mothers. But obviously this can be affected depending on method of delivery. So there are lots of studies comparing vaginal versus cesarean delivery and how that affects not only the skin microbiome, but also how that affects the gut microbiome as well. But I think there's a lot of controversy in those studies to understand the potential impacts of those different microbiomes on later life. But initially, a baby's skin is colonized with the mother's microbiota, and this generally has high proportions of bacteria that we associate as being in the vagina, such as lactobacillus and Prevotella. And there's also fungal species there as well, like Candida albicans. So a lot of what we're talking about is focusing on the bacteria, but obviously the microbiome also incorporates fungal species, viruses, archaea as well. And that initial microbiome is really important because it trains and educates the baby's immune system so that the immune system of the baby knows how to tell the difference between a good and a bad bacteria. And then And... In children, these microbial communities are very, very transient. So obviously in adults, we have this core stable skin microbiota. But this changes in children throughout development as it differentiates and grows into what we know as being the adult skin microbiome. And there are a few kind of transitional stages in this as well. So one of the key ones is adolescence as an example, because this is associated with huge changes in hormones and sebum production. And then that obviously changes our microbiome. So children don't have a lot of cutibacterium as an example, but adults do. And that transition tends to happen during adolescence. With the Amazonian tribes, I think those studies are really interesting because they allow us to characterize the skin microbiomes of these indigenous communities, and gain some insight into what our skin microbiome would have looked like prior to industrial revolution and the use of antibiotics. Arctic so it's really allowing us to understand how modern civilization has altered our microbiome and the implications for this in health and disease as you mentioned the skin of the amazonians harbors bacteria that have been lost in the western world so a lot of these bacteria are bacteria that we associate with the environment so kind of soil bacteria water from the rivers bacteria from the rivers as an example and it's likely that they are procuring some kind of key evolutionary advantage to these hunter-gatherer communities that we don't require now in our kind of industrialized environments. But what is really interesting from those studies, as you mentioned, is that increase in diversity and the fact that those communities are less prone to a lot of skin conditions. So it's likely that this information is going to help us in really understanding why we are now in this era where a lot of people are more prone to allergies to acne to asthma for example um what i found really interested in those amazonian studies as well is that the researchers that were working on on these hunter-gatherer communities showed that the microbiota from these communities harbors antimicrobial resistance genes and i find this really interesting because these people are assumed to have never been exposed to antibiotics before so it's suggesting that our microbiota already have these antimicrobial resistance gene reservoirs that are already poised to fight antibiotics even pre-exposure to antibiotics and obviously this is huge in terms of medicine because obviously antibiotics have been an incredible development for modern medicine but at the same time we're now focused with this global health challenge of antimicrobial resistance systems. So. To know now that our skin just naturally harbors these antimicrobial resistance reservoirs, it might help us to understand why we are developing such widespread multi-drug resistance across lots of different strains of bacteria. And it's also interesting that as we get older as well, our antimicrobial resistance reservoirs increase. So it suggests that as we get older, we're more likely to develop an antimicrobial resistant infection just by the fact that the microbiota that live on our skin are naturally more resistant to those drugs that we're treating patients with.

Sheena:

That that is really interesting isn't it and and do you think there's any way that these populations have got exposure to antibiotics in some way or form um through their diet or through their environment in any way because Because obviously the West has encroached on the Amazon for a while.

Guest:

So there's two kind of ways to think about it. So it could be through exposure to man-made antibiotics. For example, maybe the antibiotics that could have gotten to the watercourses is one example. Or obviously if lots of researchers are going into these communities or they're coming onto mainland and having access to things, then that might obviously increase the chance of being exposed to man-made antibiotics but the other thing is also to think about the fact that we've developed antibiotics based on what we've learned from nature so obviously penicillin was originally created from mold so a lot of the it could just be that there's a lot of similarities in the genes so the antimicrobial resistance genes that are found in the people in the amazon are not necessarily targeted against these man-made antibiotics that we've made but they could just be natural antibiotic resistance genes that are produced by the bacteria against other bacteria but they are so so similar to to the ones that we're looking at in modern bacteria that they actually would confer resistance to our modern man-made antibiotics yeah.

Sheena:

That's really interesting and and obviously these microorganisms are just changing and adapting all the time aren't they You know, it seems to be important, therefore, if these Amazonians have a lovely, rich, diverse population of bacteria on their skin and they don't really get skin disorders, then it appears to have a similar protective mechanism to what we think of in the gut microbiome. You know, greater richness and diversity gives greater resilience and, you know, it can rebound back after infections much more readily and it can protect you from disease much more readily. So it seems to be a similar kind of story with the skin. But can you tell us, you know, is that the case?

Guest:

Yes. So I think a lot of what we're learning now in the skin, we're way, way, way behind what we know in terms of the gut. But I think for the skin, a lot of the time you can take lessons from the gut. And this is definitely one of those situations where what is happening in the gut is matching up to what we see in the skin. So having a rich and diverse population of bacteria appears to be important in the skin. And we do see reduced microbial diversity in the skin of people that we we know tend to be more at risk of having skin infections or skin complications or impaired wound healing. So for example, the elderly and diabetic have altered community structures in their microbiome. So they have less diversity and they also have more presence of pathogens on their skin as well. And there's examples with atopic dermatitis as an example where you also you see in atopic dermatitis that the microbiome shifts and this shift correlates with whether there's a disease flare or not. So when there is a disease flare, you see that the diversity of the microbiome goes down and there's an increased amount of pathogens like Staphylococcus aureus. And then when the disease flare goes down, the microbiome diversity goes up and returns to baseline. So there are these direct correlations between having that rich and diverse population of bacteria correlating with having a healthy skin environment. And we also know that, as we mentioned earlier, that the skin plays wide ranging roles in maintaining an effective barrier, preventing those infections and disease. So having that resilience and having that high variety and diversity of the microbiome is really important.

Sheena:

Yeah, yeah, yeah. So on that, if we want a really rich, diverse population of bacteria, I mean, obviously we can't all just up sticks and go and live in the jungle. How can we do that in our modern lives? You know, if we're living in the middle of the city, how can we diversify our skin microbiome?

Guest:

So it's actually quite challenging at the moment because there's very, very little research into this area. So right now, it's hard to say how we can actually modify our microbiome. And the general consensus is if you have a healthy skin, then your skin is already going to have a the health of microbiome and it's more that if you have issues with your skin then we need to start looking towards how can we modulate the microbiome to improve the skin's health in those situations so there are a lot of studies where you know clinical studies now that are going through where they are trying to do things to modulate the microbiome for example so this can be via using prebiotics, probiotics, postbiotics, I mean, methods as well. So there are studies where they are transplanting commensal bacteria that we know are really good for the skin onto people's skin who have skin conditions, and that is fighting against the pathogens that are on the skin, and that's helping to improve the skin condition, such as acne. We know that people are also modifying the bacteria as well. So if we have a bacteria, we know that a certain factor is really good for the skin, then we can do genetic engineering of the bacteria to make them produce lots of that factor and then put that on someone's skin. So there have been studies in wombs where they have put, for example, lactobacillus, that they have engineered to produce factors that promote wound healing and they've thrown the lactobacillus into those wombs. And then that has improved wound healing it's combated those pathogens in those wound environments so it's not something that we have available on the shelves to us right now and but probably in the near future we will be able to start kind of pick and choose in these probiotic postbiotic various different microbiome modulating agents and putting those on our skin interesting.

Sheena:

And so So going back to your sort of wound healing, tell us about your current research and what it is you're finding when it comes to wound healing, because that's a really interesting area. I mean, everybody gets wounds. We all get them from time to time. We all want them to heal up really quickly. We don't want infections. You know, we don't want horrible scars. So what are you finding with your research?

Guest:

Yeah, so I think it's actually quite an under-researched area, wound healing. And I don't think a lot of people, if you say cancer to somebody, they know what a cancer is. But when you say chronic wound, people are a bit less sure, unless they've had a direct experience of a chronic wound, they're a bit less sure about what that actually is. But as you said, we're all getting injuries all the time. They are going to be prone to infections. We might go in for surgery and then think there's surgical site wounds that then need to heal as well. So it is a very diverse area. Burns are another type of wound. wound so it is something where we do need to be doing more research and understanding the role of the microbiome in various different types of healing processes. So the primary condition that my lab researches is these chronic non-healing skin wounds. They primarily affect the elderly and diabetic and they can be pretty devastating for the patients that have those because they're at more risk of amputations and sepsis and other types of infections as well. So what we're really trying to do is understand what is driving poor healing in these patients so that we can both prevent these wounds from happening in the first place and also effectively treat them because we don't really have very good treatments for these wounds. Most of the time it's a case of sticking a wound dressing on and hoping it heals. So within this our group is looking at the microbiome. And we're using DNA sequencing approaches to characterize the microbiome in elderly and diabetic people with and without wounds so that we can understand what's different between healthy versus aged or the diabetic microbiome so we can start to manipulate that and target it. We've also been profiling the microbiome of chronic wounds and we've found that actually the microbiome profile of a wound upon presentation in the clinic can actually predict whether the wound will go on to heal six to 12 weeks later. So that's really demonstrating that that core microbiome is really, really important to determine whether a wound will heal or not. And it also suggests that hopefully sometime in the near future, we might also be able to use the microbiome as a predictive screening approach to basically identify those patients that are most at risk and be able to stratify them and get them the treatment that they'll need. So something as well that's really important in microbiome research, we talk about all these studies that everyone's doing, but a lot of these are correlative profiling studies. So you see that somebody has acne, you swab them and then you show that their microbiome is different to someone that doesn't have acne. But obviously this is kind of just correlation and we really need more studies that are taking a multi-pronged approach to understand what is driving those changes. Is Is it that the microbiome is changing and then driving acne? Is it that the acne is happening and then the microbiome is changing in response to that? So we're also now trying to make more suitable laboratory models to be able to investigate this because in the skin community, because we are so far behind where we are in the blood, we don't have suitable models at the moment to be able to look at the role that the microbiome play functionally in the skin. So we've just received research to take some of our existing skin models for microbiome research and really translate them and make them more clinically relevant. And then finally, if we just go back to wound infections and antibiotics. So we're obviously interested in looking just at the microbiome, but we're also interested in figuring out better ways to tackle infections. And one of those that we're working on is by developing microbial agents that just target specific pathogens. Because now we're starting to appreciate the microbiome is really important. Broad spectrum antibiotics can sometimes also be really bad for infections because what can happen in those situations is the broad spectrum antibiotics kill the native microbiome and then the only bacteria that's left in that environment is the antimicrobial resistant bacteria that then has no competition and that can thrive really well so we've been developing targeted antimicrobials that only kill Staphylococcus aureus. And some of our preclinical research has shown that we can use these targeted antimicrobials to just kill that pathogen, restore the natural skin microbiome, and then accelerate healing. So we're hoping that these kinds of studies that we're doing now will work their way through clinical trials and then eventually get to patients and then offer a valid alternative to current antimicrobial treatments.

Sheena:

I think that's really encouraging actually because you know that's what we worry about as doctors as medics you know that we're giving this antibiotic and and the fallout from giving the antibiotic is that we're then knocking out all these beautiful beneficial microorganisms that we're discovering are really really doing a good job for us and we don't want to knock out these populations so so I think that makes a lot of sense to be able to to home in on the the ones that are really causing the problem, the bacteria that are really problematic and try to reduce that population. And I like also what you were saying before about using other bacteria to lower the populations in the same way that we sort of use. Probiotic bacteria you know to to increase the richness and diversity of those populations of beneficial bacteria and that then has that knock-on effect of knocking down the population of harmful bacteria in a very sort of antimicrobial way so we're using the sort of antimicrobial properties of these very beneficial microorganisms and you know i i've done that um you know through just using things like natural yogurt and things like this but interestingly i've used natural on my skin occasionally when, you know, actually around my eyes, interestingly, I had some blepharitis and it wasn't clearing with normal bathing. So I put natural yogurt in my eye, which is probably not the smartest thing to do, but it actually really cleared my eye up. And, you know, my thinking was to use those natural bacteria to outnumber the harmful ones that were driving the inflammation in my eye and it certainly appeared to work. It was a wee bit stingy though. Maybe the lactic acid in the yogurt was maybe a little bit acidic for my eye. But I just did it as an experiment. I wouldn't recommend it to all the listeners, by the way. But are we at the stage where we could start using these probiotic preparations? I know that there are companies out there producing probiotics for the skin. Could we start using things like this for wounds that are not healing or for situations like that?

Guest:

I think potentially in the future we will be able to. I think that what we really need is some kind of evidence-based research to demonstrate that this would be a good approach to take. As i said earlier you know probiotic there has been some preclinical studies to show that probiotics can modulate the microbiome in wounds and then improve wound healing and it seems like the most obvious path to take but obviously a lot of these companies that are also developing these, skin products that contain probiotics postbiotics are having to also deal with the challenges around being able to for example with probiotics it's thinking about how do you formulate those probiotics how do you kind of keep them alive in the formulation for people to be able to use and gain those benefits so i think that's something that is kind of challenging in terms of the cosmetics field is how how to actually incorporate those into products that people can use and be able to demonstrate those effects.

Sheena:

And if we go to sort of skincare in general, you know, since I learned about the skin microbiome, I have changed my skincare regime a little bit. I was quite perturbed that I might be knocking out a lot of the population of lovely bacteria on my skin through my use of soaps. And so I decided to stop using soap and see what happened to my skin microbiome and see whether or not I could tolerate not using soaps. And it's an interesting experiment, but I have actually not been using soaps on my skin now for around about two or three years now. And I only use shampoo still on my hair because I can't tolerate not having clean hair. And I couldn't I couldn't persevere with that one but I did find that it was quite interesting just going from using soap daily to not using soap on my skin because I found that my skin did stop developing a lot of sort of very minor imperfections I don't have a skin disease as such but even just minor imperfections little things little spots little separate warts these type of things. I haven't developed so many of these since I stopped using soap. And the other interesting thing for me was that I was always having to moisturize my legs because they were really dry all the time. And I haven't had to use moisturizer on them since I stopped using soap. So I've definitely noticed an improvement in my skin since I stopped using soap. So what do you think about that holly do you think that there's much evidence base for for that or do you think we should still use soaps i.

Guest:

Think i kind of agree with you here in terms of kind of soaps and chemicals i think the best way to think about kind of what is good for the skin is going to be good for the microbiome as well so i think that's kind of when we're thinking about soaps if they're going to aggravate your skin then that's obviously going to have an effect on your microbiome as well and if you're using soaps that are stripping all of those natural oils, then that is going to have an effect on those commensal bacteria. So I do think that there is value in this and it's kind of the same as your hair as well. You know, when you're talking about using the shampoos, you find if you're washing your hair more often, it gets greasier faster and faster and faster. Whereas if you kind of slow down on that, your hair balances itself and your skin balances itself self as well. So I definitely agree that kind of moving away from those more harsh chemicals and products that are going to strip the skin of its natural oils is obviously the way to go in terms of kind of maintaining that healthy skin and healthy barrier and also healthy microbiome. And I think, you know, my skincare routine has also changed over time, especially as I've learned more around the microbiome and kind of moving away from those more hard products. And I think, you, It used to be when you were a teenager years ago, you'd be throwing all kinds of harsh chemicals on your skin to deal with your acne. And obviously, that just aggravates acne. That just makes it worse. So anything where you can be reducing that stress on the skin is going to have a good effect. Because inflammation is going to drive changes in the skin microbiome and then that is going to aggravate the skin. I think there's also a lot of links between the gut and skin as well. So any type of gut inflammation or stress to the body um is also going to have an impact on the skin so maintaining good gut health is inadvertently going to be good for the skin health as well.

Sheena:

Yeah no absolutely i agree with that and interestingly um i i've also found that moving to sort of more natural skin oils you know essential oils seems to be um much better or harmonizing the the oil control in my face um and and certainly i have a daughter going through puberty um and and getting acne in her skin and and actually when we change to more natural skin products like face oils and just made from essential oils we found that her um her sebum balance was much improved um and her skin was much improved on the on all the natural products guts um so i do wonder whether we should be adopting sort of more natural means with our skin a little bit more readily um and and i'm interested also in the the sort of phytochemicals that natural plant oils contain in comparison to things like mineral oil and whether or not these are having an additional effect because i know that plant polyphenols and phytochemicals are utilized by the the gut bacteria um and and i wonder is it the same in the skin microbiome do they do the skin microbiota utilize those phytochemicals and is it beneficial then for them.

Guest:

Yes so it's the same in the skin so the skin can utilize those chemicals and the skin bacteria can utilize those chemicals and then it can also then lead to greater production of ceramides as an an example another lipids to increase moisture levels and you know maintain the skin barrier what's also really interesting is that um a lot of those phytochemicals also incorporate um things that are good for the skin separate to the microbiome so they have lots of antioxidant properties and we know that that's especially in terms of skin aging that's really important we know that there are those links between skin aging and the microbiome we just don't know, kind of what is driving what we don't know if it's the changes in you know more wrinkles means your bacteria going to change or your bacteria change and then drive more wrinkles but definitely. Having access to more of those natural plant-derived products not only can have a positive effect on the skin microbiome but it can have a direct effect on the skin. We work a lot as well separate to the microbiome but they are probably linked and we probably should be looking at this is we work a lot on phytoestrogens and kind of those natural soy type products from plants because we know especially in women when you go through the menopause circulating oestrogen drops and that is directly correlated with skin aging so as soon as a woman goes through menopause their skin rapidly declines they're more at risk of lots of different types of skin conditions and you can actually reverse that a lot of people obviously take HRT and that kind of reverses that but there are negative connotations with HRT some people are more at risk of cancer etc so by using those more natural phytoestrogens that's one way of been able to get around that um but then also you know thinking about the the beneficial effects that those phytoestrogens could potentially have on the microbiome as well and.

Sheena:

Can you i mean obviously you'd be ingesting most of those phytoestrogens through eating soy and things like that i mean is there are there products for using um phytoestrogens on the skin uh, is there anything that you could apply to the skin directly that would help with the aging.

Guest:

I'm not sure if there are any on the market at the moment um i think there are there are products that contain obviously the the kind of the plant derived um phytochemicals but i'm not sure if any of those are estrogen linked but yeah if you if you go to lots of different um, suppliers you can find those kind of natural phytoestrogen tablets and things and you can take those every day um i know a lot of people that do take those natural estrogens and soy derived products purely for the for the beneficial effects that they have in terms of skin aging.

Sheena:

Interesting and i also know that you know in in terms of skin care um a lot of people use um things like natural yogurt on their face or kefir just on their skin as a sort of face mask type thing. I've got a good friend, Janice, who is my fermenting buddy, and she uses kefir on her skin and she reckons that that really improves her skin and is very anti-aging. And she has great skin. So I'm wondering how much is actually influenced by that and whether you think that these bacteria in the kefir could have that impact.

Guest:

I think definitely because obviously in the gut that fermentation process is really important. It generates lots of factors that are really important in terms of dampening inflammation and protecting the body. So one of those main products that is produced during fermentation in the gut is butyrate and there have been studies to show that butyrate if you put butyrate on the skin it also has those beneficial effects and it's very very recently been shown now that the bacteria that live on your skin can actually produce butyrate so we didn't know that before so there are things that have been produced in the gut by bacteria in the gut that actually our skin are also capable of producing through those same fermentation processes and just to very quickly come back to those amazonian tribes who have the brilliant skin and diverse microbiomes um so i went to the the amazon rainforest a very long time ago for completely different reasons but while i was there we walked through some of the tribes and we had to drink these fermented liquid products that they had produced from kind of you know fermenting sugars etc and i do wonder kind of if they're naturally consuming these fermented products as well is that also have an effect on their health and their microbiome that's.

Sheena:

Interesting isn't it um i think a lot of the the cultures that eat or consume a lot of fermented foods certainly tend to tend to do well with longevity don't they um yeah no it's really interesting the other one that i'm wondering about that we've obviously been using in medicine for a while is raw honey. Interestingly, I had a case very recently of somebody with a wound within the mouth, actually, that wasn't healing at all. And we tried all the sort of usual tricks that we have medically wise, and nothing was working on this. And it was a horrible ulcer. And my patient rather smartly got some manuka honey and started applying the manuka honey to it. And got complete clearance of this ulcer in her mouth within a week or so. And obviously with long-term wounds like the ones that you were describing in the diabetics, these nasty ulcers in the lower legs that we see a lot that just don't heal, we have used honey in these patients and there are honey dressings as well. Do you know much about how honey is working and what that's actually doing?

Guest:

Yes, so honey is known to have natural antimicrobial and also anti-inflammatory properties. And there have been a lot of studies to show that that can have that beneficial effect on wound healing. I think it's certainly, especially in certain people, it can have that beneficial effect. And there are these honey containing dressings available on the market. Market but I think the reason that they're not widely used clinically is I think partly because, a lot of the time that clinicians are treating these patients they're using the general standard products that they are being given and kind of not deviating from that I think there's a lot of, socioeconomic considerations to take there as well if they can use a much lower cost dressing then that might be used instead but then I think on the opposite side of that you do have people that are just very recalcitrant. So even if you put something like a honey-containing dressing on their wound, it might not have the effects that you would want it to have. So I think kind of being able to have, different options is useful. And I think maybe being able to do something where we are directly modulating the microbiome would potentially be able to deliver those positive effects as well. But yeah, honey is great for lots of reasons. I definitely recommend honey.

Sheena:

Yeah. And I'm really fortunate because my dad has lots of bees. And so we always have tons of raw honey at home. And yeah, I'm a big fan. So thank you so much, Holly. That has been really, really interesting for me. I thought I knew a bit about the skin microbiome, but I definitely know a lot more now. So thank you so much. You've really taught us a lot today. And I'm really interested to hear where your research takes you on this, because, you know, I think we definitely need more scientists like yourself that can keep, you know, pushing the boundaries of research and and finding out more about what we can do to maintain these really healthy ecosystems. And I think this stuff should really be common knowledge for our clinicians as well who are working with skin. On that, by the way, is there anything that you're doing to get that knowledge base out to clinicians?

Guest:

So at the moment, a lot of what I do is working kind of collaboratively with industry so that that's in terms of because a lot of academia is very kind of insular and we don't engage externally a lot of the time so we are really trying to push that and one of the ways is by kind of working more with industry partners so that we can develop more products that are evidence-based and will have those effects and we in our group as well we work with the clinical departments at our institution so we think that that's obviously really important to have that those two-way conversations between what we're doing and the clinicians and also bringing in patients into the discussion as well so we do a lot of work with patients and public involvement to see what they're thinking about the research that we're doing because at the end of the day there's no point doing some research and not thinking about the clinical side and what the patients think and then getting to the end of that and then realizing that actually that treatment would not be practical for patients. So it's something that I think historically it was always you know ignored and I think a lot of basic research was more you know we're looking at this because we're interested in it whereas now I think it is moving more in a translational direction and there is more of a kind of a push to be working more with patients, with clinicians, collaborations with industry as well, so that we can really develop those products that, can actually make a difference yeah.

Sheena:

Yeah i mean you know the products are one side of the coin but as we we already know with microbiomes um you know they need a natural approach too um and and i think it's really important to go back to nature and appreciate you know what nature does for our microbiomes and as you say you know living in the amazon rainforest having that exposure to soil exposure to you know natural um springs and things like that you know that's something that um you know if we had better uh less polluted countrysides and riverways um you know we could we could essentially have a more enriched microbiome from spending more time in nature and you know i'm sure that if you compared skin microbiomes of of nice organic uh gardeners like my parents and and people who live in the city you'd probably find big differences in their skin microbiome um see.

Guest:

We we have done a small amount of work on that actually so we've we've compared um kind of socio-economic backgrounds so we've we've swabbed skin from people from elderly people that are in socially deprived areas versus elderly people that are in more affluent areas and they're going out and they're playing a lot of golf and keeping very active and their microbiomes are completely different so it's not just about the fact that you're going to get old and your microbiome is going to change you can do things to prevent that from happening also from just like a health and environment perspective so that the microbiome of the elderly people that are more active and are living in those affluent areas mimics more of the microbiome that you see in younger people whereas the people that are living in those more socially deprived areas they have more incidents of health problems they're smoking their microbiome is the the microbiome that is going to make you more susceptible to a chronic wound.

Sheena:

Okay, so lots of things that we can do essentially to enhance our microbiome just through our lifestyle, which is what Shiv and I talk about all the time really. And I think that's an important message. you know when you if you have a skin disorder or even if you don't have a skin disorder and you just want a really healthy skin microbiome then you know spend some time in nature get out and exercise meet friends you know diversify your skin microbiome from from getting out there and and and having lots of exposure to to the natural environment as well as eating a healthy diet and getting your sleep. You know, all these things are important. So thank you so much. I think on that note, we've covered the skin microbiome pretty well today. Obviously, there's lots more we could discuss. And I would love to have some more conversations on other clinical skin disorders at some stage. But thank you so much, Holly. You've given me lots of your time today. And And I've learned a lot. So thanks so much for coming.

Guest:

Thank you. It's been great. Thank you.