Investigating the gut microbiota's influence on psoriasis and psoriatic arthritis risk: a Mendelian randomization analysis

Role of miRNAs in the pathogenesis of psoriasis and psoriatic arthritis: a genome-wide Mendelian randomization study

BACKGROUND

MicroRNAs (miRNAs) are critical in the onset and treatment of skin diseases, but the miRNAs causally associated with psoriasis (PSO) and psoriatic arthritis (PsA) remain unclear. This study aims to identify miRNAs with causal associations with PSO and PsA.

METHODS

Five Mendelian randomization (MR) methods were employed, using miRNA expression quantitative trait loci (mirQTL) data as exposure variables and PSO and PsA as outcome variables. This approach was used to uncover the causal links of miRNAs with both PSO and PsA, with robust sensitivity analyses ensuring the stability of our findings. Finally, miRNet and enrichment analyses were used to predict target genes of the causal miRNAs and their potential biological roles.

RESULTS

Our robust findings indicated that miR-27b-3p, miR-204-5p, and miR-6891-3p were notably associated with an enhanced risk of PSO. Additionally, miR-6891-3p was greatly associated with an enhanced risk of PsA. Conversely, miR-29c-3p, miR-181a-3p, miR-181a-5p, miR-181b-5p, and miR-199a-3p were substantially associated with a reduced risk of both PSO and PsA. Enrichment analyses revealed that the target genes of these causal miRNAs were markedly enriched in biological pathways such as apoptosis, Wnt, and PI3K-AKT signaling.

CONCLUSION

This study identifies eight miRNAs causally associated with PSO and five miRNAs associated with PsA, with no observed heterogeneity or pleiotropy. These findings offer potential biomarkers for the diagnosis and treatment of PSO and PsA. Key Points • We conducted the first genome-wide MR study to explore the causal relationships between miRNAs and PSO and PsA. • The study found stable and reliable causal effects of 8 miRNAs on PSO and 5 miRNAs on PsA. • These miRNAs provide important insights into elucidating the pathophysiological mechanisms of PSO and PsA and developing new therapeutic approaches.

Antibiotics in inflammatory arthritis and background population one year before and after diagnosis: a nationwide drug utilization study

OBJECTIVES

To describe antibiotic use in patients with inflammatory arthritis (IA) and in the background population (BP) within one year before and after IA diagnosis.

METHODS

Using data from Danish nationwide registries, we identified all adults with a first-time diagnosis of RA, PsA, or AS/spondyloarthritis (AS/SpA) from 2010 through 2018. For each IA patient, we randomly sampled 10 persons from the BP, matched on sex and birthdate. We calculated the prevalence (n [%]) of any antibiotic dispensing and the total antibiotic dispensing in the year before and after diagnosis.

RESULTS

We identified 28 504 new-onset IA patients (RA, n = 16 130; PsA, n = 5988; AS/SpA, n = 6386) and 285 040 BP individuals. Within one year before diagnosis, the total amount of dispensed antibiotics was higher in both RA, PsA and As/SpA compared with the BP (prevalence rate ratios [PRR], 1.48 [1.46; 1.51]; 1.67 [1.62; 1.72]; 1.52 [1.47; 1.56], respectively). The amount increased with 22% in IA patients three months before diagnosis compared with the preceding three-month period.  Although the prevalence of any antibiotic dispensing in IA patients decreased in the year following the diagnosis (IA; 40.6%), the total one-year antibiotic dispensing remained constant in RA (PRR 0.99 [0.97; 1.01]), decreased in PsA (0.91 [0.87; 0.94]) and increased in AS/SpA (1.08 [1.04; 1.12]) patients after diagnosis compared with before.

CONCLUSION

Antibiotics are more frequently dispensed to individuals developing IA compared with the BP. Antibiotic utilization patterns change after IA diagnosis with marked differences among IA subgroups.

Investigating the causal relationship between skin microbiota and hypertrophic scar using bidirectional mendelian randomization

BACKGROUND

Hypertrophic scar (HS) is acknowledged as a pathological fibro-proliferative disease of the dermis, resulting from excessive connective tissue growth. HS significantly impacts patient quality of life due to both social and functional issues. Despite various treatments, therapeutic effectiveness remains limited, necessitating further exploration of underlying factors and mechanisms.

OBJECTIVE

The current study was designed to determine the causal relationship between skin microbiota and HS employing a bidirectional Mendelian randomization (MR) approach.

METHODS

We utilized genome-wide association study (GWAS) data from the PopGen cohort and the FinnGen database. Independent single nucleotide polymorphisms (SNPs) linked to the skin microbiota were identified as instrumental variables (IVs) chosen for the two-sample MR analysis. Key analytical approaches included inverse variance weighting (IVW), MR-Egger, simple median, simple mode, and weighted mode, with MR-Egger intercept test and Cochrane's Q test used to detect potential horizontal pleiotropy and heterogeneity.

RESULTS

The two-sample MR analysis identified significant causal relationships between specific skin microbiota features and HS. Notably, Enhydrobacter, Micrococcus, and Acinetobacter on moist skin exhibited protective effects against HS, whereas Finegoldia and Lactobacillales on dry skin were linked to an increased risk of HS. Sensitivity analyses verified the strength of these results, revealing no notable horizontal pleiotropy or heterogeneity.

CONCLUSION

Our research reveals a unidirectional causal relationship between certain skin microbiota and HS, suggesting that modulation of skin microbiota could be a novel therapeutic approach for HS management. These results emphasize the significance of considering skin microbiota in the pathogenesis and treatment of HS.

Refractory psoriatic arthritis: emerging concepts in whole process management

Psoriatic arthritis (PsA) is a chronic and progressive inflammatory arthritis associated with psoriasis, mainly affecting the axial and peripheral joints, characterized by a wide range of complex phenotypes, significant heterogeneity, and a multifactorial etiology. To effectively address the distinct challenges in managing PsA, a pivotal emphasis is placed on clarifying the concept of refractory PsA. Here, we propose a distinction between refractory PsA, differentiating between difficult-to-treat PsA (D2T PsA) and Pseudo-D2T PsA. The former centers on the lack of efficacy of multiple disease-modifying anti-rheumatic drugs (DMARDs) and signs suggestive of active/progressive disease, while also considering the challenges posed by comorbidities. The latter focuses on misdiagnosis and mismanagement, detailing the difficulties caused by artificial factors, whether by clinicians or patients. Hoping the clarification of these distinctions will enable clinicians to manage patients with refractory PsA more effectively.

The causal relationship between hydatidiform mole and nutrients: A two-sample Mendelian randomization study

BACKGROUND

Hydatidiform mole (HM), a subset of gestational trophoblastic disease, is considered precancerous and exhibits geographical variation. The incidence of HM is linked to nutritional factors. This study aimed to investigate the causal relationship between nutrients and HM using a bidirectional two-sample Mendelian randomization (MR) approach.

METHODS

We utilized publicly available genome-wide association study data to assess the causal associations between levels of specific vitamins (retinol, vitamins B12, B6, C, D, E, folate, and carotene) and minerals (iron, calcium, and magnesium) with HM. The MR analysis was conducted and reported following the STROBE-MR guidelines, employing MR Egger and inverse variance weighted (IVW) methods to estimate associations, with MR-PRESSO for pleiotropy testing.

RESULTS

The study revealed vitamin B6 as a significant protective factor against HM (MR-Egger OR: 0.094, 95 % CI: 0.011-0.0778, P < 0.05; IVW OR: 0.365, 95 % CI: 0.142-0.936, P < 0.05). Folate and magnesium showed suggestive associations with HM, whereas most other nutrients did not exhibit a causal relationship. MR-PRESSO analysis supported the absence of horizontal pleiotropy of vitamin B6. Besides, reverse MR analysis did not reveal a significant causal association between HM and serum nutrient levels, suggesting that differences of nutrients in HM patients may not be directly attributed to the mole.

CONCLUSION

This MR study provides evidence that vitamin B6 may protect against HM, and suggests potential roles for folate and magnesium in HM development, while highlighting the need for further research to confirm these findings.

Causal Relationship of Skin Microbiota on Psoriasis: A Mendelian Randomization Study

Objective

Epidemiological investigations have indicated an association between skin microbiota imbalance and psoriasis, however, the causal relationship has not been confirmed through Mendelian randomization (MR). MR employed genetic instrumental variables (IVs) to evaluate the causal relationship between skin microbiota and psoriasis, providing new insights for potential treatments.

Methods

Summary statistics for psoriasis and related traits were available from FinnGen R10 and United Kingdom Biobank (UKB) consortium. The genome-wide association studies (GWAS) on skin microbiota in three skin microenvironments came from two population-based German cohorts. Several selection processes were used to determine the optimal instrumental variables. Five MR methods were performed and different sensitivity analyses approaches yield robustness evidence under different assumptions.

Results

449 SNPs were employed as IVs for 53 bacterial genera, with F-statistics between 20.18 and 42.44, indicating no evidence of weak instrument bias. Bacteroides was associated with psoriasis from UKB in IVW (OR, 95% CI: 0.914, 0.869-0.961; P < 0.001, PB-H = 0.007). The taxon was also associated with psoriasis vulgaris (IVW: OR, 95% CI, 0.918, 0.872-0.967; P = 0.001, P B-H = 0.054) and psoriasis and related disorders (IVW: OR, 95% CI, 0.915, 0.875-0.957; P < 0.001, P B-H = 0.008). Consistent causal estimates were identified in terms of both magnitude and direction, indicating a protective effect of Bacteroides.

Conclusion

The MR study found that Bacteroides in the antecubital fossa may protect against psoriasis, offering genetic proof that skin microbiota helps prevent the condition.

Gut microbiota and psoriasis: pathogenesis, targeted therapy, and future directions

Background

Psoriasis is one of the most common autoimmune skin diseases. Increasing evidence shows that alterations in the diversity and function of microbiota can participate in the pathogenesis of psoriasis through various pathways and mechanisms.

Objective

To review the connection between microbial changes and psoriasis, how microbial-targeted therapy can be used to treat psoriasis, as well as the potential of prebiotics, probiotics, synbiotics, fecal microbiota transplantation, diet, and Traditional Chinese Medicine as supplementary and adjunctive therapies.

Methods

Literature related to the relationship between psoriasis and gut microbiota was searched in PubMed and CNKI.

Results

Adjunct therapies such as dietary interventions, traditional Chinese medicine, and probiotics can enhance gut microbiota abundance and diversity in patients with psoriasis. These therapies stimulate immune mediators including IL-23, IL-17, IL-22, and modulate gamma interferon (IFN-γ) along with the NF-kB pathway, thereby suppressing the release of pro-inflammatory cytokines and ameliorating systemic inflammatory conditions.

Conclusion

This article discusses the direction of future research and clinical treatment of psoriasis from the perspective of intestinal microbiota and the mechanism of traditional Chinese medicine, so as to provide clinicians with more comprehensive diagnosis and treatment options and bring greater hope to patients with psoriasis.

Gut microbiota's influence on erysipelas: evidence from a two-sample Mendelian randomization analysis

Background

Previous studies have suggested a link between gut microbiota and skin diseases, including erysipelas, an inflammatory skin condition. Despite this, the precise nature of the relationship between erysipelas and gut microbiota remains unclear and subject to debate.

Methods

We conducted a Mendelian Randomization (MR) analysis using publicly available summary data from genome-wide association studies (GWAS) to explore the potential causal relationship between gut microbiota and erysipelas. Instrumental variables (IVs) were identified using a comprehensive set of screening methods. We then performed MR analyses primarily using the Inverse Variance Weighted (IVW) method, complemented by alternative approaches such as MR Egger, weighted median, simple mode, and weighted mode. A series of sensitivity analyses, including Cochran's Q test, MR-Egger intercept test, Mendelian Randomization Pleiotropy RESidual Sum and Outlier (MR-PRESSO) test, and a leave-one-out test, were executed to ensure the robustness and validity of our findings.

Results

We identified potential associations between erysipelas and various gut microbiota, including Alcaligenaceae (OR 1.23; 95% CI 1.06-1.43; p=0.006), Rikenellaceae (OR 0.77; 95% CI 0.67-0.90; p=0.001), and others. Notably, associations with Actinomyces, Lachnospiraceae NC2004 group, Ruminiclostridium 9, Ruminococcaceae UCG014, Odoribacter, and Actinobacteria were also observed. Sensitivity analyses confirmed the robustness of these associations.

Conclusion

Our MR analysis suggests both potentially beneficial and harmful causal relationships between various gut microbiota and the incidence of erysipelas. This study provides new theoretical and empirical insights into the pathogenesis of erysipelas and underscores the potential for innovative preventive and therapeutic approaches.

The Role of the Gut Microbiome and Microbial Dysbiosis in Common Skin Diseases

Dermatoses are an increasingly common problem, particularly in developed countries. The causes of this phenomenon include genetic factors and environmental elements. More and more scientific reports suggest that the gut microbiome, more specifically its dysbiosis, also plays an important role in the induction and progression of diseases, including dermatological diseases. The gut microbiome is recognised as the largest endocrine organ, and has a key function in maintaining human homeostasis. In this review, the authors will take a close look at the link between the gut-skin axis and the pathogenesis of dermatoses such as atopic dermatitis, psoriasis, alopecia areata, and acne. The authors will also focus on the role of probiotics in remodelling the microbiome and the alleviation of dermatoses.

The Skin Microbiome and Its Role in Psoriasis: A Review

The skin microbiome is made of various microorganisms, most of which have the function of protecting individuals from harmful pathogens, and they are involved in innate and adaptive immune responses. The skin acts as a physical and immunological barrier against external stimuli, including pathogens and physical damage. Changes in the composition of the skin microbiome can trigger inflammatory processes leading to inflammatory skin diseases in susceptible individuals. Psoriasis (PsO) is a chronic inflammatory disease with a multifactorial etiology, where breakdown of immune tolerance to cutaneous microorganisms is implicated in its pathogenesis. Dysregulation of the microbiome due to genetic and environmental factors plays a significant role in the development of psoriatic disease. Dermatologic conditions such as atopic dermatitis, acne, psoriasis, and rosacea have been associated with intestinal dysbiosis. The skin microbiota composition is crucial for the development of appropriate immune responses, and alterations in the skin microbiome can contribute to changes in physiology and susceptibility to skin diseases or inflammatory conditions. Understanding the microbial settlement of the skin and the network of interactions that occur throughout life is essential for comprehending the pathogenesis of skin diseases and developing innovative treatments. With this article we tried to explore the relationship between the human microbiome and psoriatic disease, shedding light on the functions of the microbiome and the inflammatory disease processes to identify additional therapeutic targets. This review aims to highlight the relationship between skin and gut microbiome functions and inflammatory processes in skin psoriasis and psoriatic arthritis (PsA). The goal is to facilitate future studies on the skin microbiome to identify potential novel therapies for patients with psoriatic disease.