Investigation on Microecology of Hair Root Fungi in Androgenetic Alopecia Patients

Heat-treated Limosilactobacillus fermentum LM1020 with menthol, salicylic acid, and panthenol promotes hair growth and regulates hair scalp microbiome balance in androgenetic alopecia: A double-blind, randomized and placebo-controlled clinical trial

BACKGROUND

Androgenetic alopecia (AGA) is a common and chronic problem characterized by hair follicle miniaturization.

AIMS

In this study, heat-treated Limosilactobacillus fermentum LM1020 (HT-LM1020) was investigated in human follicle dermal papilla cell (HFDPC), scalp tissue, and clinical trials for patients with AGA.

PATIENTS/METHODS

Cell proliferation and the expression of cyclins and cyclin-dependent kinases (CDKs) were measured in HFDPC. The relative gene expression of 5α-reductase and growth factors were investigated in hair scalp. This double-blind, randomized, placebo-controlled clinical trial was conducted over 24 weeks. Primary efficacy was evaluated by measuring hair density, and secondary efficacy was assessed by experts and self-assessment. Changes in the microbiota of the hair scalps were analyzed using 16S metagenome amplicon sequencing.

RESULTS

HT-LM1020 promoted cell growth (p < 0.001) and cyclin B1 expression, and it reduced 5α-reductase and induced fibroblast growth factor 7 (FGF7), FGF10, and epithelial growth factor7 (EGF7) (p < 0.001). In the clinical trial, the experimental group demonstrated an increase in hair density from 133.70 to 148.87 n/cm2 at Week 24 (p < 0.001), while also expressing satisfaction with their hair density, reduced hair loss, and hairline. At Week 24, the total ratio of lactic acid bacteria operational taxonomic unit (OTU) in the scalp increased from 6.65% to 26.19%. At the same period, placebo-controlled group decreased Staphylococcus caprae OTU from 77.95% to 14.57% while experimental group decreased from 65.80% to 41.02%.

CONCLUSIONS

These present results showed that HT-LM1020 was a co-effector of ingredients for anti-hair loss contributing to cell proliferation and the expression of CDKs.

Illuminating microflora: shedding light on the potential of blue light to modulate the cutaneous microbiome

Cutaneous diseases (such as atopic dermatitis, acne, psoriasis, alopecia and chronic wounds) rank as the fourth most prevalent human disease, affecting nearly one-third of the world's population. Skin diseases contribute to significant non-fatal disability globally, impacting individuals, partners, and society at large. Recent evidence suggests that specific microbes colonising our skin and its appendages are often overrepresented in disease. Therefore, manipulating interactions of the microbiome in a non-invasive and safe way presents an attractive approach for management of skin and hair follicle conditions. Due to its proven anti-microbial and anti-inflammatory effects, blue light (380 - 495nm) has received considerable attention as a possible 'magic bullet' for management of skin dysbiosis. As humans, we have evolved under the influence of sun exposure, which comprise a significant portion of blue light. A growing body of evidence indicates that our resident skin microbiome possesses the ability to detect and respond to blue light through expression of chromophores. This can modulate physiological responses, ranging from cytotoxicity to proliferation. In this review we first present evidence of the diverse blue light-sensitive chromophores expressed by members of the skin microbiome. Subsequently, we discuss how blue light may impact the dialog between the host and its skin microbiome in prevalent skin and hair follicle conditions. Finally, we examine the constraints of this non-invasive treatment strategy and outline prospective avenues for further research. Collectively, these findings present a comprehensive body of evidence regarding the potential utility of blue light as a restorative tool for managing prevalent skin conditions. Furthermore, they underscore the critical unmet need for a whole systems approach to comprehend the ramifications of blue light on both host and microbial behaviour.

Clinical Translation of Microbiome Research in Alopecia Areata: A New Perspective?

The continuous research advances in the microbiome field is changing clinicians’ points of view about the involvement of the microbiome in human health and disease, including autoimmune diseases such as alopecia areata (AA). Both gut and cutaneous dysbiosis have been considered to play roles in alopecia areata. A new approach is currently possible owing also to the use of omic techniques for studying the role of the microbiome in the disease by the deep understanding of microorganisms involved in the dysbiosis as well as of the pathways involved. These findings suggest the possibility to adopt a topical approach using either cosmetics or medical devices, to modulate or control, for example, the growth of overexpressed species using specific bacteriocins or postbiotics or with pH control. This will favour at the same time the growth of beneficial bacteria which, in turn, can impact positively both the structure of the scalp ecosystem on the host’s response to internal and external offenders. This approach, together with a “systemic” one, via oral supplementation, diet, or faecal transplantation, makes a reliable translation of microbiome research in clinical practice and should be taken into consideration every time alopecia areata is considered by a clinician.

Scalp Microbiome and Sebum Composition in Japanese Male Individuals with and without Androgenetic Alopecia

The skin microbiome and sebum may be associated with inflammation-related diseases of the scalp. To assess the pathogenesis and progression of androgenetic alopecia (AGA), we analyzed the composition of sebum and the bacterial and fungal microbiomes of the scalps of 118 Japanese male individuals with and without AGA, then discussed their roles in the pathogenesis of AGA. Sebum triglyceride and palmitic acid contents were higher in the AGA group than in the non-AGA group. Malassezia restricta, a lipophilic fungus that consumes palmitic acid, was abundant on the scalps of patients with AGA. Cutibacterium, Corynebacterium, and Staphylococcus were the most common genera in both groups, and patients with AGA exhibited scalp dysbiosis (increased abundance of Cutibacterium and decreased abundance of Corynebacterium). Our findings suggest that both sebum and the bacterial and fungal microbiomes of the scalp may be involved in the development of AGA.

Exploring the human hair follicle microbiome

Human hair follicles (HFs) carry complex microbial communities that differ from the skin surface microbiota. This likely reflects that the HF epithelium differs from the epidermal barrier in that it provides a moist, less acidic, and relatively ultraviolet light-protected environment, part of which is immune-privileged, thus facilitating microbial survival. Here we review the current understanding of the human HF microbiome and its potential physiological and pathological functions, including in folliculitis, acne vulgaris, hidradenitis suppurativa, alopecia areata and cicatricial alopecias. While reviewing the main human HF bacteria (such as Propionibacteria, Corynebacteria, Staphylococci and Streptococci), viruses, fungi and parasites as human HF microbiome constituents, we advocate a broad view of the HF as an integral part of the human holobiont. Specifically, we explore how the human HF may manage its microbiome via the regulated production of antimicrobial peptides (such as cathelicidin, psoriasin, RNAse7 and dermcidin) by HF keratinocytes, how the microbiome may impact on cytokine and chemokine release from the HF, and examine hair growth-modulatory effects of antibiotics, and ask whether the microbiome affects hair growth in turn. We highlight major open questions and potential novel approaches to the management of hair diseases by targeting the HF microbiome.

The Potential Relevance of the Microbiome to Hair Physiology and Regeneration: The Emerging Role of Metagenomics

Human skin and hair follicles are recognized sites of microbial colonization. These microbiota help regulate host immune mechanisms via an interplay between microbes and immune cells, influencing homeostasis and inflammation. Bacteria affect immune responses by controlling the local inflammatory milieu, the breakdown of which can result in chronic inflammatory disorders. Follicular microbiome shifts described in some inflammatory cutaneous diseases suggest a link between their development or perpetuation and dysbiosis. Though the hair follicle infundibulum is an area of intense immunological interactions, bulb and bulge regions represent immune-privileged niches. Immune privilege maintenance seems essential for hair growth and regeneration, as collapse and inflammation characterize inflammatory hair disorders like alopecia areata and primary cicatricial alopecia. Current research largely focuses on immunological aberrations. However, studies suggest that external stimuli and interactions across the follicular epithelium can have profound effects on the local immune system, homeostasis, and cycling. Herein, we review hair follicle bacterial colonization, its possible effects on the underlying tissue, and links to the pathogenesis of alopecia, beyond the pure investigation of specific species abundance. As skin microbiology enters the metagenomics era, multi-dimensional approaches will enable a new level of investigations on the effects of microorganisms and metabolism on host tissue.

Characteristics of healthy and androgenetic alopecia scalp microbiome: Effect of Lindera strychnifolia roots extract as a natural solution for its modulation

OBJECTIVE

The human scalp harbours a vast community of microbiotal mutualists. Androgenetic alopecia (AGA), the most common form of hair loss in males, is a multifactorial condition involving genetic predisposition and hormonal changes. The role of microflora during hair loss remains to be understood. After having characterized the scalp microbiota of 12 healthy male subjects and 12 AGA male subjects (D0), the aim of this investigation was to evaluate the capacity of Lindera strychnifolia root extract (LsR) to restore a healthy bacterial and fungal scalp microflora after 83 days (D83) of treatment.

MATERIAL AND METHODS

The strategy used was based on high-throughput DNA sequencing targeting the encoding 16S ribosomal RNA for bacteria and Internal Transcribed Spacer 1 ribosomal DNA for fungi.

RESULTS

Test analysis of relative abundance comparing healthy and AGA subjects showed a significant increase of Cutibacterim acnes (P < 0.05) and Stenotrophomonas geniculata (P < 0.01) in AGA subjects. AGA scalp condition was also associated with a significant (P < 0.05) decrease of Staphylococcus epidermidis relative abundance. A lower proportion of Malassezia genus in samples corresponding to AGA scalps and an increase of other bacterial genera (Wallemia, Eurotium) were also noted. At the species level, mean relative abundance of Malassezia restricta and Malassezia globosa were significantly lower (P < 0.05) in the AGA group. Eighty-three days of treatment induced a significant decrease in the relative abundance of C. acnes (P < 0.05) and S. geniculata (P < 0.01). S. epidermidis increased significantly (P < 0.05). At the same time, LsR treatment induced a significant increase in the proportion of M. restricta and M. globosa (P < 0.05).

CONCLUSION

Data from sequencing profiling of the scalp microbiota strongly support a different microbial composition of scalp between control and AGA populations. Findings suggest that LsR extract may be a potential remedy for scalp microbiota re-equilibrium.