Knowledge grows exponentially
When I started my career in science, in my student-mind, I saw a knowledge-landscape, much like a jigsaw with large areas of missing pieces just waiting to be filled. At one extreme there was the world of physics, maths and computing. In the middle, I saw chemistry with the disciplines covering the various biologies leading through to psychology and the arts, placed at the other extremity.
Over time my flat knowledge-landscape had to become a sphere to accommodate the many connections between the different scientific disciplines. The rate of new discoveries grew steadily and then seemed to suddenly explode exponentially with the arrival of algorithm-driven computing taking DNA technology to new heights. For example, the human genome, with about 3 billion nucleotides, took 13 years to sequence starting back in 1990 but by 2017 the whole human genome could be sequenced in an hour. Suddenly, my knowledge-landscape was rapidly changing as 100s of the missing jigsaw pieces were put in place. Among many other things, the new DNA technologies revealed was the true extent of the human microbiome.
It was clear that thousands’ more microbes were living in us and on us than we had previously realised, and the compositions of our microbiome can affect our health, beauty and well-being. Cosmetic science is therefore just one of many disciplines finding itself running to catch up.
Microbiome – the missing step
Outnumbering our human cells types by around 10 to 1, the gut microbiome holds answers to many imponderables, such as why one individual may respond to treatment better than another. Differences in identical twin can be epigenetic but they can also be due to their different microbiome. Evidence is amassing on how the dynamic interactions between our intestinal epithelium and our gut microbiota/metabolites, influence our immune system.
Researchers have compared the gut microbiome composition of allergic and non-allergic infants and seen significant differences. Could our infant gut microbiome have prepared us (or not) to respond proportionately to antigens? Atopic Eczema is one disorder that has been linked to low bacterial diversity in the gut, particularly in the Proteobacteria and Bacteroidetes phylum. Interestingly, Proteobacteria cell walls contain lipopolysaccharide, which can trigger an immune response and infants subject to low exposure to lipopolysaccharides are at higher risk of atopic eczema.
Most exciting, with implications that microbiome composition could be controlling our well-being, is the discovery that two-way neuronal, hormonal and immunological signalling takes place between our gut and our brain.
Stress influences the integrity of the gut epithelium and alters peristalsis, secretions and mucin production, which in turn alters the composition of the intestinal microbiome. Could this work in reverse with the gut microbiome reducing stress? Studies are linking low numbers or the absence of certain bacteria in the gut microbiome sampled from people suffering from depression. This chicken and egg situation is a fast-developing area of interest that potentially opens doors to a different way of understanding and managing mood.
Skin Microbiome Modulation – No more Mr Bad Guy.
Since the 1890s, Koch postulate has underpinned medical thinking on assigning microbes to diseases. Based on cause and effect, the original postulate asserts that bacteria must be isolated from the host with the disease and grown in pure culture. The specific disease must reoccur when the pure bacterial culture is introduced into a healthy subject. The same bacteria must them be present in the newly infected host and the bacteria must be present in every case of the disease. Early microbiologists, intent on finding a microbe responsible for acne, isolated acne bacillus from acne lesions.
Back in the 1890s, it was noted then that these slow-growing isolates were always contaminated with faster-growing bacteria. In 1899, Gilchris succeeded in preparing pure cultures of acne bacillus, directly from acne nodules by planting the gelatinous contents on an acid glycerin agar. The isolated acne bacillus was later renamed Propionibacterium acnes (P. acnes), and strains were shown to be capable of synthesising a gelatinous biofilm. With thanks again to DNA technologies, the classification of P. acnes has been changed from Propionibacterium to Cutibacterium, so P. acnes is now correctly known as Cutibacterium acnes (C. acnes). Despite not fulfilling all the criteria stipulated in Koch’s postulate, for decades P. acnes had been labelled as the bad guy responsible for skin blemishes and acne type conditions.
With the imponderable that P. acnes was present on most people, yet most people did not have blemished skin, products for clear skin have fixated on reducing or eliminating P. acnes. Thankfully, as we learn even more about the skin microbiome’s complex and interdependent communities the cosmetic industry is beginning to move away from talk of bad guys and towards modulating the microbiome. Consequently, the Skin Microbiome Modulators Market is being predicted to Reach $2.97 Billion by 2030. Coming soon C. acnes – the probiotic of choice? And what should we expect to come next? Perhaps soon, genetically modify microbiome bacteria will be detecting and directing changes in the skin.
Rather than trying to reduce C. acnes, Cargol’s team in Spain are taking advantage of their abundance on skin and in sebaceous glands. They are using the latest gene editing tools to turn C. acnes into in situ sensors, sensitive to external changes which sense threatening levels of UV radiation or in internal changes such as hormone levels.
Once a change is detected, they could initiate a response in skin and so could become the cosmetic formulator’s probiotic of choice for controlling sebum or for soothing and reducing inflammation.
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