April 18, 2024

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Skin flora research and development: Cosmetics or pharmaceuticals?

Skin flora research and development: Cosmetics or pharmaceuticals?

Skin flora research and development: Cosmetics or pharmaceuticals?  In the past ten years, the rapid development of microbiome research has promoted the development of the microbiome industry. However, most of the microbiome research and microbial start-up companies treat the gut microbiota as a target. However, in recent years, with the rise of research on extraintestinal flora, skin flora has also attracted more and more attention.

Today, we are jointly focusing on startups in the skin microbiome industry, and specially compiled an article entitled “Out of your skin” published in Nature Biotechnology magazine. I hope this article can bring some inspiration and help to related industry professionals and readers.



Outside the intestine: skin flora

In the past ten years, almost all researches on the microbiome have been related to the gut. The annual investment in microbiome research funds is as high as 1.8 billion US dollars, but most of them are used for intestinal research. Product development in this field is also mainly for intestinal-related diseases; it can also be seen in the publication of the paper that the human microbiome is published Of the approximately 3,000 papers published in China, research on intestinal flora accounts for the vast majority.

But the gut’s monopoly on the development and commercialization of the microbiome may end. In October last year, the startup Azitra announced that it had received US$14 million in Series A financing to expand its clinical trials of microbial products for various skin diseases. This reflects people’s growing confidence in the skin as a microbial product to control inflammation or defend against pathogens.

Azitra’s main product, an engineered strain of Staphylococcus epidermidis, is in the first phase of clinical trials for the treatment of cancer-related rash (CTAR).

In addition, there are many start-up companies in the treatment of acne, atopic dermatitis (also known as eczema), athlete’s foot and other skin diseases at different clinical stages (Table 1).

The old model of treating some of these diseases is being replaced by a different way of thinking: these diseases are manifested in a state of dysbacteriosis, so they can be improved by re-nourishing the skin with beneficial microorganisms, rather than eliminating them with drugs.

But the question is, in a market dominated by cosmetics companies, how can microbial companies not only develop and grow, but also have sufficient resources to establish safe and effective product projects without having to meet the same standards?

Skin flora research and development: Cosmetics or pharmaceuticals?
Table 1. Some companies are developing microbial-based skin therapies



Largest organ

As the largest human organ, skin covers an area of ​​18 square feet (about 1.67 square meters) of our body. It is a barrier to prevent physical trauma, toxins, environmental damage and pathogenic organisms from invading. At the same time, it also provides a habitat for symbiotic microorganisms including bacteria, fungi and viruses. The exact number of resident microorganisms on the skin is difficult to obtain, but it is estimated that the number of microorganisms on the skin is about one-tenth of that in the intestine (ie 10 per square centimeter [5]).

The surface of the skin (stratum corneum or the outermost layer of the epidermis) is a dry and nutrient-poor environment composed of chemically cross-linked dead cells (non-nucleated keratinocytes), which are shed at an alarming rate: an average of 200 million sheds per hour Nearly 5 billion cells are shed every day.

The part of the epidermis below the stratum corneum consists of a layer of differentiated keratinocytes, which is interspersed with other cells such as melanocytes, Langerhans cells (an antigen presenting cell), Merkel cells (related to touch), and peripheral sensory nerves .

Another 90% of the skin is composed of the dermis, which contains other structures such as blood vessels, lymphatic vessels, hair follicles, sebaceous glands and sweat glands, all of which provide favorable conditions for the reproduction of microorganisms. Sweat itself contains antimicrobial peptides (AMPs) and fatty acids, while sebaceous glands secrete lipid-rich sebum. This is a lubricating, water-resistant coating that also has antibacterial properties, especially against gram-positive bacteria (Figure 1).

The complexity and stability of the skin microbiome vary with specific skin parts. It is important for protecting the body from environmental pathogens, regulating the immune system, and decomposing natural products.

Richard Gallo, chair of dermatology at the University of California, San Diego, is excited about recent progress in regulating skin microbes as a treatment for disease.

He said: “We are going beyond the level of genus or species and strains. We can now know the genes that the skin microbiome has and how to use them for treatment. In the intestine, the purpose of treatment is to correct the imbalance of the flora. /The imbalance of resident microorganisms that cause health risks. Ideally, microbiome therapy can target the underlying mechanisms of skin diseases, not just the symptoms.”

Yasmine Belkaid, head of the Metaorganism Department of Immunology at the National Institute of Allergy and Infectious Diseases under the National Institutes of Health (NIH), also believes that the skin microbiome has broad therapeutic potential.

But she reminded that the interaction between microorganisms and the interaction between microorganisms and human cells not only differ from one strain to another, but also from strain to strain. Even if they promote health in some environments, they may also cause disease in other conditions. “If you don’t know the outcome that affects the response,” Belkaid said, “then the treatment may be counterproductive.”

Skin flora research and development: Cosmetics or pharmaceuticals?

Figure 1. Skin flora: The skin provides a different environment to accommodate different microorganisms. Image source: A. L. Byrd, Y. Belkaid & J. A. Segre, Nat. Rev. Microbiol. 16, 143–155 (2018).



Deep skin products

Skin care products sold as cosmetics, food or dietary supplements have begun to promote the health promotion effect of the “microbiome”.

These products include an increasing number of probiotics (live cultures of beneficial bacteria, such as Lactobacillus plantarum and Bifidobacterium longum), prebiotics (compounds that act as a source of nutrients for skin symbiosis), and even “epibiotics” (beneficial bacteria) Secondary metabolites and other natural products such as lipids and proteins).

Some cosmetics also include non-living microbial agents, called “lysates”, which claim to be able to modulate the microbiome to produce benefits, but there is very little data on mechanisms that clarify how they exert these effects.

In the field of unregulated cosmetics and supplements, companies that make health promotion claims (rather than claiming a role in treating or preventing diseases) do not need to provide regulatory agencies with evidence of the efficacy of their products (Box 1). According to Gallo, since most of these products do not have to undergo rigorous efficacy trials, “it is difficult to know how effective any of these products is.”

He added that to determine that regulating the microbiome is beneficial, relevant verification is needed. “However, with high-quality science and meticulous clinical trials, I am optimistic that treatment strategies based on the skin microbiome may have a transformative impact on medicine.”

Why does the commercialization of the skin microbiome lag behind companies that focus on intestinal diseases? One of the reasons is that the skin is different from the intestine, and the skin lacks an “integrator” of microbial activity, said Eric de La Fortelle, a partner at Seventure Partners, a life science venture capital firm based in Paris.

Intestinal researchers believe that fecal samples can reflect the microbial activity of the entire intestine, while the skin microbiome varies depending on the skin location, hygiene level and environmental conditions. de La Fortelle explains: “It is therefore difficult to draw general information about the disease. Laws and the specific link between microorganisms and diseases.”

Sampling the skin microbiome is also a challenge. Compared with the nutrient-rich intestinal environment, the skin temperature is relatively low, the pH is acidic, and in addition to basic proteins and lipids, it also lacks nutrients. Microorganisms on the skin adapt to this environment by ingesting available resources in sweat or sebum. The cells in a typical stool sample are almost all bacteria, but about 99% of the skin swabs are human cells. “So it is difficult for scientists to collect enough microbial DNA from the skin for analysis.” Gallo said.


Box1: Current State of Supervision

According to the intended use, skin care products can be divided into cosmetics and medicines and supervised accordingly.

The U.S. Food, Drug, and Cosmetic Act defines drugs as products used to diagnose, treat, or prevent diseases. Products containing living organisms are called living biological drugs (LBPs). In contrast, cosmetics refer to products used to clean, beautify, or change the appearance of the body.

Like other drugs, LBPs must obtain pre-market approval under the FDA’s New Drug Application Process (NDA), which requires corresponding trials in human volunteers. According to Paul Richards, spokesperson for the FDA’s Center for Biologics Evaluation and Research, the FDA does not distinguish between natural and genetically engineered LBPs. However, FDA approval is not required before cosmetics are marketed.

If a product is developed in the European market for the treatment or prevention of diseases, it is regulated by the European Medicines Agency as LBPs. The relevant legislation is the European Parliament Directive 2004/27/EC and the revised European Community Medicines for Human Use 2001/83 /EC directive. If the purpose of the product is to clean, protect, deodorize or change the appearance of the human body, the relevant legislation is Directive 1223/2009, and the supervision and supervision will be transferred to the national authorities.

So, is there any flexibility in the regulation of European companies’ declarations on cosmetics? Bernhard Pützold, one of the founders of S-Biomedic, stated that the dividing line between European therapeutics and cosmetics is “not as clear as in the United States”.

S-Biomedic has chosen to develop microbial-based acne treatment products for the European consumer market because the choice of drugs requires years of clinical testing. Pützold added: “But we can’t use the same propaganda methods to promote sales in the United States.”

According to Magali Cordaillat-Simmons, director of scientific and regulatory affairs at the Pharmabiotic Institute in Napona, France, European authorities “will not regulate misleading information as long as the target population is not dangerous to use the product.”

However, she added that regulators may take measures to “clean up the market” in the next few years, and reminded that if cosmetics claims are highly misleading and pose risks to consumers, then “the authorities will sooner or later Time to catch you.”


Shotgun sequencing

However, the breakthrough of shotgun sequencing has opened the door to the skin microbiome for us, and at the same time brought treatment opportunities.

According to Julie Segre, head of the Division of Translational and Functional Genomics at the National Human Genome Institute of the National Institutes of Health, this method can capture all the genetic material in low-biomass samples (human and non-human samples) and provide enough Resolution to distinguish bacterial species and even strains.

The data so far show that in oily (face and chest), moist (groin) and dry (forearms and palms) body parts, bacteria are the most abundant skin microbes, and fungi are the least, although these differences also reflect that bacteria have more More reference genomes are available for comparison.

“Bacteria seem to work more easily with people,” Segre said, “but that doesn’t mean they are the most important.” She said that research on phages and eukaryotic viruses is particularly inadequate and requires further attention.

Emerging research results reveal how skin microbes are affected, and in turn, are affected by the biological makeup of the host.

Skin microbes regulate the developing immune system and play a very important role in inflammation and defense against pathogens. Belkaid said, for example, under the stimulation of microorganisms, immune cells can even migrate to other tissues of the body, such as the lungs.

Various bacteria also stimulate human cells to release AMPs, and some bacteria also produce their own AMPs to control pathogens. For example, Staphylococcus epidermidis and another commensal bacteria, Staphylococcus human (and possibly other bacteria) release AMPs, which kill Staphylococcus aureus. Among them, methicillin-resistant Staphylococcus aureus strains are considered to be one of the most dangerous staphylococci.

According to Gallo, human skin has evolved an extraordinary ability to protect the microbiota. Millions of hair follicles and sebaceous glands provide niches for established communities. Considering these tiny pits, the skin is actually the largest epithelial surface where the human body interacts with microorganisms.

Gallo cites a study that shows that habitual exposure to certain strains or strains can lead to long-term colonization. He said this shows that under the right conditions and with the right strains, even daily cleaning , It is also possible to supplement new skin microorganisms. However, he added: “This is not easy to achieve because the existing resident microorganisms will develop resistance and they want to protect their ecological niche.”

Biotechnology companies are taking advantage of this newly discovered biology. But the gut and skin markets are developing in different ways.

Intestinal microbial therapy starts with undefined mixtures, such as fecal bacterial transplantation (FMT), and then develops to single strain treatments-whether natural or engineered-and finally develops to microbial products with pharmaceutical effects.

Julia Oh, an assistant professor at the Jackson Laboratory in Farmington, Connecticut, said that the microbial content on the skin is too low, and the three-dimensional structure of the skin itself is too complex to be suitable for treatment similar to FMT.

She said: “Most of the applications you see are the use of single strains in local locations. This is the direction of development I see.”

Also according to Cain McClary, managing partner of KdT Ventures, a life science venture capital firm, there has not been significant progress in purifying biologically active microbial-derived compounds as a reasonable treatment for skin diseases.

McClary pointed out that most skin diseases are caused by the destruction of the skin barrier, which then leads to the reproduction of pathogens such as Staphylococcus aureus. Therefore, he said, these conditions are easier to receive simple treatment than those that affect the intestinal tract.


Unmodified strain

Unmodified strains can be used as a therapeutic agent. MatriSys Biosciences has developed a human Staphylococcus preparation for patients with atopic dermatitis, which affects approximately 11% (35 million) of the U.S. population. The company claims that commensal staphylococcus is a powerful alternative to current treatments, which include dilute bleach, antibiotics, steroids and moisturizers.

The skin of patients with atopic dermatitis colonizes high levels of Staphylococcus aureus and lacks AMPs, such as antimicrobial peptides and β-defensins. Without these antibacterial drugs to prevent its growth, Staphylococcus aureus will multiply on the skin, exacerbating inflammation and related disease symptoms.

In 2017, Galloa, co-founder of MatriSys, reported that the use of Staphylococcus human preparations for one day can inhibit the growth of Staphylococcus aureus on the skin of patients with atopic dermatitis.

According to Mark Wilson, President and CEO of MatriSys, these findings have been repeated in a 7-day study that showed a statistically significant improvement in symptoms of atopic dermatitis (such as rash and itching) .

Galloa said that the unpublished results of the study will be announced at the next Annual Meeting of the Society of Dermatology Investigations in Scottsdale, Arizona, May 13-20, 2021.

MatriSys, headquartered in La Jolla, California, obtained Gallo’s intellectual property authorization from the University of California, San Diego, and successfully completed the pre-new drug application review in March last year. Thereafter, the company will join forces with an undisclosed biopharmaceutical company to plan a 16-week phase 2 trial with the proprietary strain Staphylococcus humans A9.

Wilson said that after freeze-drying and grinding, the bacteria can be stored in an anhydrous oil carrier at room temperature for more than one year.

In San Francisco, startup Naked Biome is developing an unmodified microbiome product for acne, another key skin disease market. The US subsidiary of the established dermatology pharmaceutical company LEO Pharma is one of the company’s major investors.

As a chronic skin inflammation, acne affects nearly 60 million Americans (12 million of which are adults). The disease is related to certain strains of Propionibacterium acnes, one of the most abundant residents in the skin microbiome.

Not all P. acnes carriers will have acne symptoms, which reflects how the host’s immunity and hormone status dominate the pathogenic effect of the bacteria.

In adolescence, hormone-induced increase in sebum secretion often triggers symptoms; P. acnes decomposes sebum into glycerol (the bacteria’s metabolites) and free fatty acids, thereby triggering inflammation.

The difference between the strains will determine whether it can cause acne; some disease-related P. acnes strains produce more free fatty acids than others; some strains release high levels of porphyrin, which is an inflammatory hemoglobin Metabolites. Studies have shown that from the perspective of strains, P. acnes is equally common in people with and without acne, but disease-related strains are more likely to appear in acne patients.

The current methods of treating acne have the following drawbacks: Both benzoyl peroxide and retinoic acid, two commonly used programs, can cause skin irritation and cause dry skin.

Emma Taylor, co-founder and CEO of Naked Biome, believes that adding the health-related P. acnes species to the skin will be a better way to “prevent disease-causing strains from clustering together.”

Naked Biome’s researchers used metagenomic sequencing to identify healthy P. acnes strains with clinically relevant genotype and phenotypic characteristics based on published research results, and developed the company’s main product: one A health-related P. acnes strain named MBO1 has low inflammatory potential.

In a recent phase 1b clinical trial of 14 subjects, MBO1 treatment was conducted twice a day for 12 weeks. The results showed that it was well tolerated and reduced several inflammatory markers of acne.

Taylor shared his research results at the Microbiome & Probiotics Series held in the United States, which was held in San Diego from October 29th to 30th last year. The proof-of-concept study cannot detect a significant difference from the baseline, but at least the evidence shows that microorganisms have shifted to the MBO1 genotype and have a tendency to reduce inflammatory damage.


S-Biomedic, based in Beerse, Belgium, uses what they call a bottom-up approach to study which molecules produced by P. acnes are related to acne. It turns out that one of the primary culprits is linoleic acid isomerase, which can effectively stimulate the lipid production of sebocytes, release reactive oxygen species and inflammation, thereby causing acne symptoms.

In a recently published study, S-Biomedic showed that they can regulate the skin microbiome by continuously applying a mixture of bacteria from healthy individuals. They are now working with industrial partners to prepare an isomer that produces low levels of linoleic acid. Strains of enzymes are used to make acne treatment products.

The company’s CSO Bernhard Pätzold said that due to different regulatory requirements in Europe, they will be able to launch their products over the counter (Box1). “There is a legal framework around it. We can argue very well that we are a general consumer product, especially when it comes to acne. How many acne do you need to be considered a skin disease?” he asked.

These three companies-MatriSys, Naked Biome and S-Biomedic-treat skin diseases with symbiotic bacteria isolated from human skin. But researchers will also sample other species to determine candidate strains for treatment.

When Robert Brucker was an undergraduate in conservation biology, he isolated a bacterium with antifungal properties from a red-backed salamander in a forest in Virginia. After obtaining a doctorate in biomedicine, he started a research project on applied microbes at Harvard University. He co-founded DermBiont. The bacteria, Janthinobacterium lividum, not only exists on the skin of amphibians, but also The main component of the human skin microbiota.

The bacterium is currently undergoing clinical trials to combat tinea pedis, the famous Hong Kong foot. The most common cause of foot in Hong Kong is Trichophyton rubrum, a fungus that reproduces on the upper layer of dead skin. Cases of Hong Kong foot are often described as infections, usually treated with topical or oral antifungal drugs, but the effective ratio is less than 50%.

According to Brucker, these drugs are not always effective because “the treatment model is wrong: this is not an infection, but a flora disorder.”

J.lividum will multiply on human skin, but the abundance level is very low; DermBiont’s strategy is to use a suspension of J.lividum separated from healthy human skin and incorporate it into a proprietary formula to add Great anti-fungal effect to treat Hong Kong feet.

Company representatives claimed that in the Phase 2a clinical trial completed in October last year, the probiotic therapy (DB1-001) reached the safety endpoint and improved symptoms. Currently, a Phase 2b trial is recruiting patients, and the company plans to conduct a trial of DB1-001 against fungal nail infections later this year.



Engineered strains

At the same time, some bold companies are further advancing microbiome therapy-transforming bacteria to make them more powerful to improve the effects that unmodified probiotics can achieve.

For example, Xycrobe Therapeutics has a patent for a modified strain of Propionibacterium acnes, which secretes the anti-inflammatory cytokine interleukin-10 (IL-10), which is found in peripheral blood mononuclear cells of patients with acne and psoriasis. -10 down.

Last year, Xycrobe was acquired by Crown Laboratories for an unknown amount. Thomas Hitchcock, the founder of Xycrobe, became the Chief Security Officer of Crown Laboratories. Hitchcock explained that people with low IL-10 levels overreact to the skin microbiome, making them susceptible to skin diseases.

According to the company’s patent application, the company has been testing the effect of a lactose-induced IL-10 genetically modified Propionibacterium acnes, which is linked to a signal peptide that secretes anti-inflammatory cytokines.

Xycrobe has also introduced auxotrophy into IL-10 engineered P. acnes strains (for example, by knocking out glutamine synthetase to cause glutamine auxotrophy or by knocking out aspartate kinase or aspartate Semialdehyde dehydrogenase causes aspartic acid auxotrophy) so that it can control engineered microorganisms after being released into the skin (removal of amino acids will cause starvation of engineered strains).

Azitra is also developing engineered microbial therapies. All engineering strains of the company have knocked out genes related to D-alanine biosynthesis (alanine racemase and D-alanine aminotransferase) to achieve the purpose of assisted growth, because D-alanine Amino acid is needed for these bacteria to build cell walls: by supplementing different levels of amino acids in its therapeutic formula, Azitra can control the growth of applied engineered microbial products.

Its leading product, ATR-04, is a symbiotic strain of Staphylococcus epidermidis that can defeat the pathogenic Staphylococcus aureus, which overgrows in the skin of patients receiving epidermal growth factor receptor (EGFR) inhibitor cancer treatment.

“EGFR inhibitors reduce the defenses of the skin and increase the possibility of patients getting rashes, so that in some cases, patients cannot continue to receive cancer treatment,” said Travis Whitfill, executive director of advanced technology at Azitra. “Our epidermis Staphylococcus can prevent Staphylococcus aureus from multiplying, thereby preventing infection.”

According to Whitfill, the company recently completed a phase 1 safety test, demonstrating that engineered bacteria can successfully colonize the skin, integrate with the skin microbiome, and promote the expression of the host’s immune defense system. Although it is known that Staphylococcus epidermidis can overcome pathogens by forming biofilms and may stimulate the production of host AMPs, the exact mechanism is still unclear. The company plans to conduct a phase 2 trial of CTAR in 2020.

At the same time, Azitra is also developing ATR-01 for the treatment of Netherton syndrome, a genetic disease characterized by scaly and red skin. Netherton syndrome is attributed to mutations in the SPINK5 gene, which encodes a serine protease inhibitor called LEKTI (lympho-epithelial Kazal-type-related inhibitor), which puts newborns at risk of dehydration and sepsis.

Azitra’s treatment strategy is to design a strain of Staphylococcus epidermidis to secrete LEKTI protein on the skin of patients. According to Whitfill, the company plans to submit a new drug research application and start clinical trials in the fourth quarter of 2020.


Dual business strategy

In January of this year, Azitra and Bayer signed a joint development agreement to jointly develop consumer health products for the cosmetics market, including a product for eczema skin.

As in the case of probiotic dietary supplements, the commercialization of skin cosmetics is much faster and can generate revenue faster. Currently, no drug targeting the intestinal or skin microbiome has been approved by the regulatory authorities (FMT is still considered an investigational product), but skin cosmetics based on the microbiome have been widely marketed.

For example, Dakota BioTech has a product line called LaFlore, which is marketed as “combining live probiotics with advanced science to create healthy skin at every age.”

According to the company’s CSO Maya Ivanjesku, LaFlore products contain the same bacterial species as commercial probiotic dietary supplements. Although these products have been tested for stability and toxicity, Ivanjesku stated that studies describing their efficacy or performance have never been publicly released.

Oh from the Jackson Laboratory, who works with Azitra, said that cosmetics do not need to be tested for efficacy, adding that the manufacturers of these products often make unproven claims, such as the impact of cosmetics on skin quality and hydration . But in fact, most companies in the skin microbiome field are developing cosmetics and drugs sequentially or at the same time.

Take AOBiome as an example, which was originally a cosmetics company that promoted nitrosamine oxidizing bacteria (AOB), such as Nitrosomonas eutropha. These skin symbiotic bacteria can metabolize ammonia in sweat to produce nitrite and nitric oxide (NO), which have anti-inflammatory and anti-infective properties, thereby reducing body odor.

According to the company’s CEO Todd Krueger, AOBs once appeared on human skin but were wiped out by soaps and deodorants. AOBiome claims that these bacteria can restore the skin to a “natural, healthier (and less pungent) state” and added them to a product line called Mother Dirt, which is currently licensed to SC Johnson Company, the company is a manufacturer of cleaning products.

Krueger said that after AOBiome discovered that AOBs would produce NO, a clinically promising by-product, it turned to therapeutic development.

“NO is a natural anti-infective agent,” he said, “and we don’t want to be a cosmetics company to conduct drug trials.” Currently, a proprietary bacterium has been tested for various diseases in human trials. Including wound healing and acne treatment, AOBiome is pursuing atopic dermatitis-related pruritus as its main indication.

Whitfill said that Azitra’s CTAR product was originally developed for the cosmetics market, “but then we switched to using it only for treatment because it is an engineered strain,” Whitfill said. “A lot of the big companies we talked to don’t want to Add engineered living organisms to the cosmetics market-at least not yet.”

According to Seventure’s de La Fortelle, most companies in this field are struggling to solve the problem of how to balance the benefits of beauty and treatment. It is not unusual that the same bacterial strain can be used for both purposes. He said the only difference is that therapeutic applications usually rely on higher doses, which can better “embed” into the skin and last longer.

“It all has to do with how you profit from science,” he said. “You can do cheaper cosmetic trials and sell your products faster, or you can take an expensive treatment route and get more in the future. High pricing.”

These options also play a role when biotech companies seek to acquire or collaborate with large companies. “The buyer will depend on the specific indication,” KdT’s McClary said, “and it should be noted that cosmetics partners have more hesitations about genetically modified products.”

According to de La Fortelle, dermatology and cosmetics companies have shown great interest in skin microbiome startups.

“But so far, there is very little public information about these partnerships,” he said. “We are still in the pioneering stage. But we should see a lot of the results of the second phase next year. Once we get a clear and effective treatment It proves that everyone will catch up, investment funds will follow, and promote the development of this field.”

(source:internet, reference only)

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