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.

Topical Steroid Withdrawal is a Targetable Excess of Mitochondrial NAD.

Background: Topical corticosteroids (TCS) are first-line therapies for numerous skin conditions. Topical Steroid Withdrawal (TSW) is a controversial diagnosis advocated by patients with prolonged TCS exposure who report severe systemic reactions upon treatment cessation. However, to date there have been no systematic clinical or mechanistic studies to distinguish TSW from other eczematous disorders. Methods: A re-analysis of a previous survey with eczematous skin disease was performed to evaluate potential TSW distinguishing symptoms. We subsequently conducted a pilot study of 16 patients fitting the proposed diagnostic criteria. We then performed: tissue metabolomics, transcriptomics, and immunostaining on skin biopsies; serum metabolomics and cytokine assessments; shotgun metagenomics on microbiome skin swabs; genome sequencing; followed by functional, mechanistic studies using human skin cell lines and mice. Results: Clinically distinct TSW symptoms included burning, flushing, and thermodysregulation. Metabolomics and transcriptomics both implicated elevated NAD+ oxidation stemming from increased expression of mitochondrial complex I and conversion of tryptophan into kynurenine metabolites. These abnormalities were induced by glucocorticoid exposure both in vitro and in a cohort of healthy controls (N=19) exposed to TCS. Targeting complex I via either metformin or the herbal compound berberine improved outcomes in both cell culture and in an open-label case series for patients with TSW. Conclusion: Taken together, our results suggest that TSW has a distinct dermatopathology. While future studies are needed to validate these results in larger cohorts, this work provides the first mechanistic evaluation into TSW pathology, and offers insights into clinical identification, pharmacogenomic candidates, and directed therapeutic strategies.

Interventions for anxiety and depression in patients with atopic dermatitis: a systematic review and meta-analysis.

Atopic dermatitis (AD) is a chronic inflammatory skin disease that is associated with anxiety and depression. Few studies have addressed interventions for symptoms of anxiety and depression in this population. To determine the efficacy of interventions for anxiety and depression in patients with AD. PubMed, MEDLINE, EMBASE, and PsycINFO were searched from inception to November 2023. English-language studies published in peer-reviewed journals evaluating the effect of interventions on anxiety and/or depression using validated assessment tools on patients with AD were included. Titles, abstracts, and articles were screened by at least two independent reviewers. Of 1410 references that resulted in the initial search, 17 studies were included. Fourteen of these studies are randomized controlled trials, while the other 3 studies are prospective controlled trials with pre and post-test designs. Data were extracted using a standardized extraction form, and the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were followed. To accommodate trials with multiple interventions (each compared to a control group), we conducted a mixed-effects meta-analysis with the trial as a random effect. Prespecified outcomes were changes in symptoms of anxiety and depression in patients with AD as evaluated using standardized assessment tools. Of the 17 studies included in this systematic review, 7 pharmacological intervention studies with 4723 participants examining 5 different medications were included in a meta-analysis. Of these studies, only 1 study evaluated medications prescribed to treat anxiety and/or depression; the rest evaluated medications prescribed to treat AD. Meta-analysis of all the pharmacological interventions resulted in significant improvement in anxiety, depression, and combined anxiety-depression scale scores (standardized mean difference [95% CI]: - 0.29 [- 0.49 to - 0.09], - 0.27 [- 0.45 to - 0.08], - 0.27 [- 0.45 to - 0.08]) respectively. The 10 non-pharmacological studies with 2058 participants showed general improvement in anxiety but not depression. A meta-analysis of the non-pharmacological interventions was not conducted due to variable approaches and limited data. Pharmacological interventions designed to improve AD were found to improve anxiety and depression in patients with moderate-severe disease. More comprehensive studies on non-pharmacological and pharmacological interventions that primarily target anxiety and depression are needed.

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.

Atopic dermatitis (AD) is a chronic, inflammatory disease characterized by dry, itchy skin that has become increasingly more common since around 1970. We aimed to identify chemicals that may cause atopic dermatitis (eczema). Building on prior work, we discovered that these chemicals could prevent the good bacteria that live on the skin from making the lipids and oils needed to keep human skin healthy. In this study, we combined new research methods with patient surveys. We link eczema to the chemical xylene, which is found in numerous home products. Exposure to xylene, benzene, or isocyanate containing fabrics (polyester, nylon, or spandex) disrupted the normal functions of skin bacteria. Our results indicate exposure to synthetic fabrics and other sources of these chemicals may contribute to eczema and deepen the understanding of how the environment can drive common diseases.

Examining allergy related diseases in Africa: A scoping review protocol.

During recent decades, allergy related diseases have emerged as a growing area of concern in developing regions of the world, including Africa. Worldwide prevalence of allergic diseases has grown to an estimated 262 million for asthma, 400 million for allergic rhinitis (or hay fever), 171 million with atopic dermatitis (or eczema), and over 200 million for food allergy. In Africa, considerable variability exists in the data surrounding prevalence at the continent-wide, regional, and study site levels. Furthermore, research conducted in many rural areas and underdeveloped countries in Africa remains limited, and presently, little has been done to characterize and map the extremely heterogeneous body of literature which confounds research efforts. This scoping review will seek to identify studies examining the prevalence, management strategies, outcomes, and associated risk factors for allergy related diseases in Africa. The Joanna Briggs Institute's scoping review methods will be followed, and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Review (PRISMA-ScR) was used for writing the protocol. Four databases (Embase, Global Health, PubMed, African Journals Online) will be searched for literature published from 2003 to 2023 in any language. Title and abstract screening and full-text screening will be completed by two independent reviewers using Covidence; conflicts resolved by a third reviewer. Data will be extracted using Covidence by two reviewers independently. To report the results, we will follow the PRISMA-ScR checklist and report descriptive statistics and a narrative summary.

The circadian metabolome of atopic dermatitis.

BACKGROUND: Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by dry, pruritic skin. Several studies have described nocturnal increases in itching behavior, suggesting a role for the circadian rhythm in modulating symptom severity. However, the circadian rhythm of metabolites in the skin and serum of patients with AD is yet to be described. OBJECTIVE: We sought to assess circadian patterns of skin and serum metabolism in patients with AD. METHODS: Twelve patients with moderate to severe AD and 5 healthy volunteers were monitored for 28 hours in a controlled environment. Serum was collected every 2 hours and tape strips every 4 hours from both lesional and nonlesional skin in participants with AD and location-, sex-, and age-matched healthy skin of controls. We then performed an untargeted metabolomics analysis, examining the circadian peaks of metabolism in patients with AD. RESULTS: Distinct metabolic profiles were observed in AD versus control samples. When accounting for time of collection, the greatest differences in serum metabolic pathways were observed in arachidonic acid, steroid biosynthesis, and terpenoid backbone biosynthesis. We identified 42 circadian peaks in AD or control serum and 17 in the skin. Pathway enrichment and serum-skin metabolite correlation varied throughout the day. Differences were most evident in the late morning and immediately after sleep onset. CONCLUSIONS: Although limited by a small sample size and observational design, our findings suggest that accounting for sample collection time could improve biomarker detection studies in AD and highlight that metabolic changes may be associated with nocturnal differences in symptom severity.

Patients' and Caregivers' Preferences for Mental Health Care and Support in Atopic Dermatitis.

Background: Atopic dermatitis (AD) has large mental health impacts for patients and caregivers, yet their preferences regarding how to relieve these impacts are poorly understood. Objective: To understand patients' and caregivers' preferences for AD-related mental health care and support. Methods: We surveyed 279 adult AD patients and 154 caregivers of children with AD across 26 countries regarding their AD-related mental health burden, preferred strategies for improving AD-related mental health, and experiences with mental health care in AD. Results: Caregivers reported significantly worse overall mental health (P = 0.01) and anxiety (P = 0.03) than adult patients when controlling for AD severity. Among adult patients, 58% selected treating the AD, 51% managing itch, 44% wearing clothing to cover up skin, 43% avoiding social situations, and 41% spending time alone, as strategies they felt would improve their own AD-related mental health. Caregivers selected managing itch and treating the AD most frequently for both their own (76% and 75%, respectively) and their children's (75% and 61%) mental health. Adult patients were less satisfied with mental health care from mental health providers versus nonmental health providers (P < 0.001). Conclusions: Effective AD management is the preferred method for improving mental health among patients as well as caregivers, who may experience the greatest mental health impacts. Self-care strategies should be considered in a shared decision-making approach.

A Randomized, Double-Blind, Placebo-Controlled, Multicenter, 16-Week Trial to Evaluate the Efficacy and Safety of FB-401 in Children, Adolescents, and Adult Subjects (Ages 2 Years and Older) with Mild-to-Moderate Atopic Dermatitis.

BACKGROUND: Atopic dermatitis is a common chronic, relapsing, and remitting inflammatory skin disorder associated with cutaneous dysbiosis. Current treatment options often fail to adequately control the disease and have unfavorable safety profiles. There is a need for new options that address these treatment shortcomings. OBJECTIVE: The aim of the study was to evaluate the efficacy, safety, and tolerability of FB-401, a live therapeutic product of 3 strains of Roseomonas mucosa, compared to matching placebo applied topically 3 times per week to participants ages ≥2 years of age with mild-to-moderate atopic dermatitis. METHODS: A randomized, double-blind, placebo-controlled, parallel-group study was conducted. The primary outcome was the proportion of participants with 50% improvement in Eczema Area and Severity Index score from baseline at week 16. 154 subjects aged 2 or older with a clinical diagnosis of atopic dermatitis as defined by Hanifin and Rajka criteria with mild or moderate severity were randomized 1:1 via interactive web response system to FB-401 or placebo. RESULTS: The proportion of subjects who achieved the primary outcome was similar between both treatment groups, with no significant treatment group differences observed at any post-baseline visit. The number of treatment-emergent adverse events and the number of subjects with at least one were similar across treatment groups. One serious adverse event not related to treatment was reported. No treatment-emergent adverse events led to treatment discontinuation or study discontinuation. CONCLUSIONS: FB-401 showed an acceptable safety profile but failed to prove superior to placebo in treating children and adults with mild-to-moderate atopic dermatitis.

De novo assembly of Roseomonas mucosa isolated from patients with atopic dermatitis.

Roseomonas mucosa is associated with the normal skin microflora. Here, we present de novo sequence assemblies from R. mucosa isolates obtained from the skin lesions of three atopic dermatitis patients.

De novo assembly of Roseomonas mucosa isolates from healthy human volunteers used to treat atopic dermatitis.

Roseomonas mucosa is a bacterium that is found in the natural microbiota of human skin. Here, we present de novo sequence assemblies from R. mucosa isolated from the skin microflora of three healthy human volunteers that were used to treat atopic dermatitis patients.

Antimony Compounds Associate with Atopic Dermatitis and Influence Models of Itch and Dysbiosis.

Compared to the myriad of known triggers for rhinitis and asthma, environmental exposure research for atopic dermatitis (AD) is not well established. We recently reported that an untargeted search of U.S. Environmental Protection Agency (EPA) databases versus AD rates by United States (U.S.) postal codes revealed that isocyanates, such as toluene diisocyanate (TDI), are the pollutant class with the strongest spatiotemporal and epidemiologic association with AD. We further demonstrated that (di)isocyanates disrupt ceramide-family lipid production in commensal bacteria and activate the thermo-itch host receptor TRPA1. In this report, we reanalyzed regions of the U.S. with low levels of diisocyanate pollution to assess if a different chemical class may contribute. We identified antimony compounds as the top associated pollutant in such regions. Exposure to antimony compounds would be expected from brake dust in high-traffic areas, smelting plants, bottled water, and dust from aerosolized soil. Like TDI, antimony inhibited ceramide-family lipid production in Roseomonas mucosa and activated TRPA1 in human neurons. While further epidemiologic research will be needed to directly evaluate antimony exposure with surrounding AD prevalence and severity, these data suggest that compounds which are epidemiologically associated with AD, inhibit commensal lipid production, and activate TRPA1 may be causally related to AD pathogenesis.

Survey of topical exposure concerns for patients and caregivers dealing with atopic dermatitis.

Background: Despite the recent expansion of treatment options in atopic dermatitis (AD), most management responsibilities fall on the patient and/or caregivers. Disease control often requires vigilance about and avoidance of common exposures, however the concerns for patients and caregivers living with AD have not been well enumerated. Methods: An IRB approved survey was distributed to the public to evaluate the patient and caregiver concerns for topical exposures and potential triggers. Results: 323 people accessed the link to the survey with 259 providing response to at least one section of questions (response rate 80.2%). Results indicated that temperature and other weather related changes were the most common trigger. Nearly all respondents avoided at least one topical ingredient, with fragrances being the most common. Steroid exposure was common, however respondents expressed concerns about overall steroid exposure. Conclusions: Our results attempt to enumerate the daily topical exposure concerns for patients and caregivers living with AD. While our online survey is both limited and without mechanistic insights, our results provide insight to providers by highlighting the role of temperature in AD symptoms; identifying commonly perceived triggers; indicating the value of provider insight for topical product selection; and indicating that no specific aspect of topical corticosteroid exposure may alleviate the general steroid concerns for patients or caregivers.

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

BACKGROUND: While the microbiome is increasingly seen as a targetable contributor to atopic dermatitis (AD), questions remain as to whether the dysbiosis is secondary to diseased skin or if it predates symptom onset. Previous work has evaluated how the skin microbiome changes with age and established the influence of factors like delivery mode and breastfeeding on global microbiome diversity. However, these studies were unable to identify taxa which predict subsequent AD. METHODS: Skin swab samples were collected from the first week of life for 72 children in the neonatal intensive care unit (NICU) at a single site hospital. Participants were followed for 3 years to determine their health status. We applied shotgun metagenomic sequencing to assess the microbiome differences between 31 children who went on to develop AD and 41 controls. RESULTS: We identified that subsequent development of AD was associated with differential abundance of several bacterial and fungal taxa as well as several metabolic pathways, each of which have been previously associated with active AD. CONCLUSIONS: Our work provides evidence of reproducibility for the previously reported dysbiotic signatures predating AD onset while also expanding prior findings through the first use of metagenomic assessment prior to AD onset. While extrapolation of our findings beyond the pre-term, NICU cohort is limited, our findings add to the evidence that the dysbiosis associated with AD pre-dates disease onset rather than reflect a secondary consequence of skin inflammation.

Diisocyanates influence models of atopic dermatitis through direct activation of TRPA1.

We recently used EPA databases to identify that isocyanates, most notably toluene diisocyanate (TDI), were the pollutant class with the strongest spatiotemporal and epidemiologic association with atopic dermatitis (AD). Our findings demonstrated that isocyanates like TDI disrupted lipid homeostasis and modeled benefit in commensal bacteria like Roseomonas mucosa through disrupting nitrogen fixation. However, TDI has also been established to activate transient receptor potential ankyrin 1 (TRPA1) in mice and thus could directly contribute to AD through induction of itch, rash, and psychological stress. Using cell culture and mouse models, we now demonstrate that TDI induced skin inflammation in mice as well as calcium influx in human neurons; each of these findings were dependent on TRPA1. Furthermore, TRPA1 blockade synergized with R. mucosa treatment in mice to improve TDI-independent models of AD. Finally, we show that the cellular effects of TRPA1 are related to shifting the balance of the tyrosine metabolites epinephrine and dopamine. This work provides added insight into the potential role, and therapeutic potential, or TRPA1 in the pathogenesis of AD.

Exposure to isocyanates predicts atopic dermatitis prevalence and disrupts therapeutic pathways in commensal bacteria.

Atopic dermatitis (AD) is a chronic inflammatory skin condition increasing in industrial nations at a pace that suggests environmental drivers. We hypothesize that the dysbiosis associated with AD may signal microbial adaptations to modern pollutants. Having previously modeled the benefits of health-associated Roseomonas mucosa, we now show that R. mucosa fixes nitrogen in the production of protective glycerolipids and their ceramide by-products. Screening EPA databases against the clinical visit rates identified diisocyanates as the strongest predictor of AD. Diisocyanates disrupted the production of beneficial lipids and therapeutic modeling for isolates of R. mucosa as well as commensal Staphylococcus. Last, while topical R. mucosa failed to meet commercial end points in a placebo-controlled trial, the subgroup who completed the full protocol demonstrated sustained, clinically modest, but statistically significant clinical improvements that differed by study site diisocyanate levels. Therefore, diisocyanates show temporospatial and epidemiological association with AD while also inducing eczematous dysbiosis.

Rank correlation inferences for clustered data with small sample size.

This paper develops methods to test for associations between two variables with clustered data using a U-Statistic approach with a second-order approximation to the variance of the parameter estimate for the test statistic. The tests that are presented are for clustered versions of: Pearsons χ 2 test, the Spearman rank correlation and Kendall's τ for continuous data or ordinal data and for alternative measures of Kendall's τ that allow for ties in the data. Shih and Fay use the U-Statistic approach but only consider a first-order approximation. The first-order approximation has inflated significance level in scenarios with small sample sizes. We derive the test statistics using the second-order approximations aiming to improve the type I error rates. The method applies to data where clusters have the same number of measurements for each variable or where one of the variables may be measured once per cluster while the other variable may be measured multiple times. We evaluate the performance of the test statistics through simulation with small sample sizes. The methods are all available in the R package cluscor.

Impact of Skin Tissue Collection Method on Downstream MALDI-Imaging.

MALDI imaging is a novel technique with which to study the pathophysiologies of diseases. Advancements in the field of metabolomics and lipidomics have been instrumental in mapping the signaling pathways involved in various diseases, such as cancer and neurodegenerative diseases (Parkinson's). MALDI imaging is flexible and can handle many sample types. Researchers primarily use either formalin-fixed paraffin-embedded (FFPE) or fresh frozen tissue samples to answer their scientific questions. FFPE samples allow for easy long-term storage, but the requirement for extensive sample processing may limit the ability to provide a clear picture of metabolite distribution in biological tissue. Frozen samples require less handling, but present logistical challenges for collection and storage. A few studies, mostly focused on cancer cell lines, have directly compared the results of MALDI imaging using these two tissue fixation approaches. Herein, we directly compared FFPE and fresh frozen sample preparation for murine skin samples, and performed detailed pathway analysis to understand how differences in processing impact MALDI results from otherwise identical tissues. Our results indicate that FFPE and fresh frozen methods differ significantly in the putative identified metabolite content and distribution. The fixation methods shared only 2037 metabolites in positive mode and only 4079 metabolites in negative ion mode. However, both fixation approaches allowed for downstream fluorescent staining, which may save time and resources for samples that are clinically precious. This work represents a direct comparison of the impacts of the two main tissue processing methods on subsequent MALDI-MSI. While our results are similar to previous work in cancer tissue, they provide novel insights for those using MALDI-MSI in skin.

IFNγ regulates NAD+ metabolism to promote the respiratory burst in human monocytes.

Interferon γ (IFNγ) is an essential and pleiotropic activator of human monocytes, but little is known about the changes in cellular metabolism required for IFNγ-induced activation. We sought to elucidate the mechanisms by which IFNγ reprograms monocyte metabolism to support its immunologic activities. We found that IFNγ increased oxygen consumption rates (OCR) in monocytes, indicative of reactive oxygen species generation by both mitochondria and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Transcriptional profiling revealed that this oxidative phenotype was driven by IFNγ-induced reprogramming of NAD+ metabolism, which is dependent on nicotinamide phosphoribosyltransferase (NAMPT)-mediated NAD+ salvage to generate NADH and NADPH for oxidation by mitochondrial complex I and NADPH oxidase, respectively. Consistent with this pathway, monocytes from patients with gain-of-function mutations in STAT1 demonstrated higher-than-normal OCR, whereas chemical or genetic disruption of mitochondrial complex I (rotenone treatment or Leigh syndrome patient monocytes) or NADPH oxidase (diphenyleneiodonium treatment or chronic granulomatous disease [CGD] patient monocytes) reduced OCR. Interestingly, inhibition of NAMPT in healthy monocytes completely abrogated the IFNγ-induced oxygen consumption, comparable to levels observed in CGD monocytes. These data identify an IFNγ-induced, NAMPT-dependent, NAD+ salvage pathway that is critical for IFNγ activation of human monocytes.