LEO Foundation

Skin barrier dysfunction is central to inflammation and susceptibility to infection in atopic dermatitis (AD). Cutaneous T-cell lymphoma (CTCL) shares clinical similarities with AD and is also associated with a high prevalence of Staphylococcus aureus (S. aureus) colonisation. However, the mechanisms driving skin barrier damage in CTCL and the contribution of bacteria remain poorly understood. We investigate how the interplay between S. aureus (and staphylococcal enterotoxins (SEs)) and primary malignant- and non-malignant T cells affects keratinocyte expression of skin barrier proteins; invitro, in an EL4 murine lymphoma model of bacteria-driven tumour progression, and in CTCL patient lesions colonised with SE-producing S. aureus before and after bacterial eradication by antibiotic treatment. S. aureus and SEs activate malignant and non-malignant T cells to release barrier-repressing cytokines, including IL-4, IL-13, IL-22, and OSM, and JAK-dependent downregulation of filaggrin and loricrin in keratinocytes. In the EL4 model, bacteria-colonised tumour-bearing mice show significant filaggrin loss in tumour-adjacent epidermis, whereas antibiotic-treated mice maintain near-normal expression. Clinically, antibiotic eradication of SE-producing S. aureus partially restores filaggrin and loricrin expression in three of four patients, paralleling reduced inflammatory signalling. SE-producing S. aureus promotes skin barrier impairment in CTCL through cytokine-driven, JAK-dependent repression of structural proteins in keratinocytes. These findings identify microbial-immune crosstalk as a contributor to CTCL skin pathology and provide mechanistic rationale for strategies targeting S. aureus colonisation as adjunctive therapy in CTCL.

Psoriasis is a chronic inflammatory disease with a well-established association with obesity. However, the role of diet remains unclear. This study examined dietary habits in patients with psoriasis and compared adherence to national dietary guidelines with matched healthy controls. We included 466 patients with psoriasis from the BIOSKIN cohort and 1,029 healthy controls from the Copenhagen General Population Study. According to a Food Frequency Questionnaire, 53% of the patients reported a “healthy and varied diet,” and 39% “no specific diet”. Approximately 10% practiced intermittent fasting, while smaller proportions followed a Mediterranean diet (4%), a ketogenic/low-carb, high-fat diet (3%), or an anti-inflammatory diet (2%). Overall, 90% showed high or intermediate adherence to dietary guidelines. Patients with mild psoriasis adhered more often to guidelines than those with moderate-to-severe disease (33% vs. 17%, p = 0.001). No significant difference in dietary adherence was observed between patients with psoriasis and matched healthy controls (p = 0.79). In conclusion, patients with moderate-to-severe psoriasis have less healthy dietary patterns compared to those with mild disease. When comparing all patients with psoriasis to healthy controls, no difference in adherence to dietary guidelines was found. Due to the cross-sectional nature of this study, the causal relationship between diet and psoriasis remains unclear.

Understanding of mononuclear phagocyte (MNP) diversity in the human intestine and the alterations this compartment undergoes in inflammation remains incomplete. Here, we used single-cell RNA sequencing, cellular indexing of trancriptomes and epitopes by sequencing, flow cytometry, and imaging to explore MNP heterogeneity in human ileal and colonic laminae propriae (LPs) in health and Crohn's disease (CD). In addition to monocytes, macrophage subsets, and conventional type 1 dendritic cells (cDC1s) and cDC2s, we found a CD1c+ cDC subset with transcriptional features of DC3s. Using computational tools, we identified monocyte-to-macrophage trajectories as well as putative subset-specific DC precursors. We further showed that LP CCR7+ cDCs are increased in CD and provided evidence that these cells arise from intestinal cDC2s/DC3s but not cDC1s. Collectively, these findings extend our current understanding of intestinal MNP diversity and development, highlighting both tissue-specific and inflammation-induced changes in MNP composition and function.

In situ forming implants (ISFIs) present a promising approach for sustained parenteral drug delivery, offering reduced first pass metabolism, fewer systemic side effects, and improved patient compliance. This study investigates defocused spatially-offset Raman spectroscopy (SORS) as a real-time, non-invasive, and label-free method for monitoring implant formation and drug release from ISFIs loaded with the model drugs 4-cyanophenol (4-CP) or all-trans retinoic acid (RA). A custom-designed flow-through diffusion cell, incorporating full-thickness porcine skin, was developed to enable ex vivo release studies, allowing simultaneous defocused SORS measurements of subcutaneously-implanted formulations and HPLC quantification of drug released into the receptor medium. Confocal Raman microscopy cross-section imaging validated defocused SORS findings, while static ex vivo release studies using Franz diffusion cells served as a reference for flow-through experiments. Both Franz cell and flow-through release studies revealed a pronounced burst release for the hydrophilic 4-CP after injection (90.7% and 94.8% released after 2.5 d under static and flow-through conditions, respectively) and a delayed, attenuated release for the hydrophobic RA (3.3% and 2.1% after 2.5 d). Defocused SORS further confirmed a correlation between implant formation and drug release, highlighting solvent exchange as a key driver of burst release. These findings demonstrate the unique capability of defocused SORS for the comprehensive, non-invasive, and real-time characterization of ISFI formulations. By combining the relevance of biological tissue with experimental accessibility, the ex vivo flow-through configuration (enhanced by defocused SORS) provides a novel and powerful platform for formulation development and individualized therapeutic drug monitoring, with strong potential for clinical translation.

As women of childbearing potential constitute a considerable portion of the total psoriasis population, dermatologists must consider both the clinical and psychosocial implications of psoriasis when treating these patients. This review summarizes key clinical considerations when treating women of childbearing potential with psoriasis, regarding family planning, pregnancy, and the postpartum period, aiming to assist in identifying common concerns within this population. Many women report initiating the discussion on family planning but having limited access to information. Concerns about the impact of psoriasis and its treatment on fertility, pregnancy, and lactation are common, and lack of adequate information can lead to irrevocable decisions. Despite conflicting results, current evidence suggests a potential negative correlation between moderate-to-severe psoriasis and fertility. Studies on adverse maternal and neonatal events associated with psoriasis show inconsistent outcomes and should be communicated with caution. With the increase in available treatment options during pregnancy and lactation, particularly in cases of severe psoriasis, personalized treatment plans are becoming more achievable, allowing dermatologists to better address the needs of their patients. The majority of patients can be treated during pregnancy with topical treatments or ultraviolet-B irradiation. While the general recommendation is to stop systemic treatment before conception, decisions should be made on an individualized basis. If treatment cannot be discontinued, tumor necrosis factor-α inhibitors and cyclosporine can be used. It is essential to inform parents of the additional risks associated with live or live-attenuated vaccines in cases where the mother has received systemic treatment during pregnancy and to delay vaccinations accordingly.

Non-healing venous leg ulcers are characterized by dysfunctional wound healing and frequently exhibit an absence of classical inflammatory signs, despite substantial bacterial loads of the Gram-negative pathogen Pseudomonas aeruginosa. To investigate this clinical observation, we used a porcine wound infection model and complementary in vitro cell and enzymatic activity assays. In vivo, P. aeruginosa infected wounds resulted in attenuated inflammatory responses compared to those infected with Staphylococcus aureus. Protease activity was elevated in P. aeruginosa-infected wounds relative to uninfected controls, while pro-inflammatory cytokine levels decreased over time. In vitro analyses employing cell cultures, wildtype and mutant strains, and clinical isolates from venous ulcers and blood, revealed that P. aeruginosa elastase (LasB) degrades a range of pro-inflammatory cytokines (G-CSF, GM-CSF, IFN-γ, IL-1ra, IL-6, IL-12p40, IL-23, TNF-α) and chemokines (Gro-α, IL-8, IP-10, MCP-1, MIP-1α, MIP-1β) in the extracellular milieu, without impacting cell morphology, transcription factor activation, or subsequent intracellular cytokine production. Correspondingly, wound fluids from non-healing ulcers colonized/infected with P. aeruginosa degraded cytokines, whereas fluids from uninfected wounds did not. Collectively, our findings indicate that P. aeruginosa modulates host inflammation by degrading cytokines and chemokines.

Structured AbstractBackgroundIndividuals with common variable immunodeficiency (CVID) are at increased risk of respiratory infections such as SARS-CoV-2 infection due to poorly understood defects within the memory B cell (MBC) compartment. The COVID-19 pandemic presented a unique opportunity to investigate the effects of a novel pathogen and vaccination on the immune system of patients with CVID.MethodsA cross-sectional, single-center, cohort study was used to evaluate the immunologic effect of SARS-CoV-2 vaccination and/or disease on the immune system. We examined the antibody levels, neutralization capacity, MBC, and CD4+T follicular helper cell (TFH) response against two SARS-CoV-2 variants in 23 CVID patients and 51 age- and sex-matched healthy individuals with both vaccine-induced and hybrid immunity across multiple immunization events.ResultsOur study shows that while CVID patients mount a sufficient CD4+TFHresponse against both ancestral and Omicron variants, and some levels of neutralizing antibodies, Spike-specific MBC formation is severely inhibited. Only CVID patients with hybrid immunity were able to generate switched MBCs against both variants. These MBCs were transient however, as Spike-specific switched MBCs did not persist over time in CVID patients. We found that the level of switched MBCs correlated with both CD21 and BAFF-R expression in patients, many of whom expressed low levels of either receptor.ConclusionTaken together, our study shows that CVID patients generate a sufficient CD4+TFHresponse against SARS-CoV-2 but rarely cross-reactive MBCs, and suggest that this effect is correlated with CD21 and BAFF-R dysregulation which might cause switched MBC obsolescence.Trial registration21/54057.FundingLundbeck Foundation, Novo Nordisk Foundation and Odense University Hospital.

Abstract This study explores the antidiabetic potential of bioactive compounds isolated from Juglans regia Linn. fruit endocarp fractions. The ethanolic extract was screened for α ‐amylase inhibition, revealing the chloroform fraction as the most potent (18.45 ± 0.76%), followed by the n ‐hexane fraction (12.65 ± 0.52%) and results were compared to acarbose (21.84 ± 1.67%). These results were further supported by the nonenzymatic glycosylation of hemoglobin assay. Five compounds were isolated by employing column chromatography from both fractions and were structurally characterized using ¹H NMR and ¹ 3 C NMR spectroscopy. Density functional theory (DFT) analysis confirmed their stability and reactivity. Molecular docking, molecular dynamics (MD) simulations, and MM/GBSA calculations revealed that compounds 2 and 5 displayed strong interactions with human pancreatic α ‐amylase (PDB: 4GQR) and hemoglobin (PDB: 2D60), respectively. MM/GBSA analysis quantified the binding free energies, reinforcing the stability of these interactions, while MD simulations validated the dynamic behavior of these complexes over time, confirming their potential as stable inhibitors. ADMET analysis confirmed favorable pharmacokinetic and toxicity profiles, suggesting these compounds as promising candidates for diabetes treatment. This study provides a strong foundation for further drug development targeting diabetes management.