Shotgun metagenomic sequencing on skin microbiome indicates dysbiosis exists prior to the onset of atopic dermatitis

Atopic Dermatitis and Psoriasis: Similarities and Differences in Metabolism and Microbiome

Atopic dermatitis and psoriasis are common chronic inflammatory diseases of high incidence that share some clinical features, including symptoms of pruritus and pain, scaly lesions, and histologically, acanthosis and hyperkeratosis. Meanwhile, they are both commonly comorbid with metabolic disorders such as obesity and diabetes, indicating that both diseases may exist with significant metabolic disturbances. Metabolomics reveals that both atopic dermatitis and psoriasis have abnormalities in a variety of metabolites, including lipids, amino acids, and glucose. Meanwhile, recent studies have highlighted the importance of the microbiome and its metabolites in the pathogenesis of atopic dermatitis and psoriasis. Metabolic alterations and microbiome dysbiosis can also affect the immune, inflammatory, and epidermal barrier, thereby influencing the development of atopic dermatitis and psoriasis. Focusing on the metabolic and microbiome levels, this review is devoted to elaborating the similarities and differences between atopic dermatitis and psoriasis, thus providing insights into the intricate relationship between both conditions.

Does "all disease begin in the gut"? The gut-organ cross talk in the microbiome

The human microbiome, a diverse ecosystem of microorganisms within the body, plays pivotal roles in health and disease. This review explores site-specific microbiomes, their role in maintaining health, and strategies for their upkeep, focusing on oral, lung, vaginal, skin, and gut microbiota, and their systemic connections. Understanding the intricate relationships between these microbial communities is crucial for unraveling mechanisms underlying human health. Recent research highlights bidirectional communication between the gut and distant microbiome sites, influencing immune function, metabolism, and disease susceptibility. Alterations in one microbiome can impact others, emphasizing their interconnectedness and collective influence on human physiology. The therapeutic potential of gut microbiota in modulating distant microbiomes offers promising avenues for interventions targeting various disorders. Through interdisciplinary collaboration and technological advancements, we can harness the power of the microbiome to revolutionize healthcare, emphasizing microbiome-centric approaches to promote holistic well-being while identifying areas for future research.

Spatial modeling connecting childhood atopic dermatitis prevalence with household exposure to pollutants

BACKGROUND

Atopic dermatitis (AD) is a chronic, inflammatory disease characterized by dry, pruritic skin. In the U.S., the prevalence of AD has increased over three-fold since the 1970s. We previously reported a geographic association between isocyanate-containing air pollution and AD as well as mechanistic data demonstrating that isocyanates induce skin dysbiosis and activate the host itch receptor TRPA1. However, non-spatial models are susceptible to spatial confounding and may overlook other meaningful associations.

METHODS

We added spatial analysis to our prior model, contrasting pollution data with clinical visits. In addition, we conducted a retrospective case-control survey of childhood exposure to BTEX-related products. Finally, we assessed implicated compounds, in pure form and as part of synthetic fabric, for their effect on the growth and metabolism of skin commensal bacteria.

RESULTS

Spatial analysis implicate benzene, toluene, ethylbenzene, and, most significantly, xylene (BTEX) compounds. Survey odds ratios for AD were significant for xylene-derived polyester bed sheets (OR = 9.5; CI 2.2-40.1) and diisocyanate-containing wallpaper adhesive (OR = 6.5; CI 1.5-27.8). Staphylococcus aureus lives longer on synthetic textiles compared to natural textiles. Meanwhile, synthetic fabric exposure shifts the lipid metabolism of health-associated commensals (Roseomonas mucosa and S. epidermidis) away from therapeutic pathways.

CONCLUSIONS

We propose that BTEX chemicals in their raw forms and in synthetic products represent a unifying hypothesis for environmentally induced AD flares through their ability to create dysbiosis in the skin microbiota and directly activate TRPA1. Unequal distribution of these pollutants may also influence racial disparities in AD rates.

The Skin Microbiome and its Significance for Dermatologists

The skin is a physical and immunological barrier to the external environment. Its large surface area is colonized by diverse communities of microorganisms, including bacteria, viruses, fungi, and Demodex species mites. These microorganisms and their genetic material together create the skin microbiome. Physiologic and anatomic properties of skin sites create biogeographical habitats (dry, moist, and sebaceous) where distinct microbiota communities reside. Although, in general, the composition of these habitats is maintained from person to person, the skin microbiome of an individual also has unique microbial features. Dysbiosis occurs when the normal abundance, composition, or location of the microbiota is changed, most notably there is a decrease in flora diversity. Certain skin diseases, including atopic dermatitis, rosacea, and psoriasis are associated with cutaneous dysbiosis, and even disruption of the gut microbiota. Studies have shown that current treatments for these dermatologic conditions can alter/stabilize the skin microbiome, and there is emerging research detailing the impact of prebiotics, probiotics, and postbiotics on these conditions. Although clinical guidelines do not currently exist, clinical studies support the safety and possible benefits of using topical prebiotics and postbiotics and oral probiotics for a variety of skin conditions. Until such guidelines exist, utilizing carefully designed clinical studies to inform clinical practice is recommended.