HS 3D-SeboSkin Model Enables the Preclinical Exploration of Therapeutic Candidates for Hidradenitis Suppurativa/Acne Inversa

Hidradenitis Suppurativa Tunnels: Unveiling a Unique Disease Entity

Hidradenitis suppurativa tunnel structures lined with epithelium within the dermis are unique features of advanced disease stages that significantly impair patients' QOL. The presence of hidradenitis suppurativa tunnels is associated with a decreased likelihood of achieving a clinical response, even when receiving biological therapy. The cellular and molecular mechanisms underlying tunnel formation and pathology are only partially understood, which hampers the development of more effective targeted therapies. Tunnels create a unique microenvironment that drives a vicious cycle of hidradenitis suppurativa inflammation, with tunnel keratinocytes exhibiting an activated phenotype characterized by distinct gene expression signatures. In this review, we summarize the current literature and discuss aspects of the pathophysiology of tunnels, including the role of hair follicle epidermal stem cells in tunnel formation, potential role of fibroblast-mediated epithelial-mesenchymal transition, role of dermal papilla fibroblasts, and aberrant proinflammatory repair response contributing to the observed fibrosis and scarring. Finally, tunnel structures are characterized by unique microbial dysbiosis and an overabundance of Gram-negative anaerobes that are not targeted by current therapeutics. In addition to outlining the possible mechanisms of tunnel formation, we provide perspectives on the translation of current knowledge into more effective treatment approaches for patients with hidradenitis suppurativa tunnels.

Hidradenitis Suppurativa Preclinical Studies: Models and Results

Hidradenitis suppurativa is a solely human disease for which-unlike for other inflammatory dermatoses-applied animal models are not available. In order to study skin cell immunology under conditions which approximate the in vivo functions, maintenance of structural tissue integrity in experimental models is essential. Consequently, several ex vivo human models using lesional, perilesional hidradenitis suppurativa and control healthy skin, have been described, which claim to represent fast and relatively simple methods to investigate the pathophysiology of hidradenitis suppurativa and to preclinically detect the effectiveness of candidate therapeutic agents. At least some of these models seem to approximate the in vivo situation by maintaining patients' skin architecture for several days and expressing biomarkers also detected in hidradenitis suppurativa skin in vivo. Validation still remains to be performed for the majority of the models by evaluating the ex vivo efficacy of drugs, which are introduced in clinical studies and/or have been approved for HS treatment.

The Inflammatory Landscape of a Whole-Tissue Explant Model of Hidradenitis Suppurativa

Hidradenitis suppurativa (HS) is a relatively common and highly morbid inflammatory skin disease. Due to the relatively limited understanding of HS's pathogenesis, there are currently insufficient treatment options available, and many patients' medical needs are not being met. This is partly due to the historical scarcity of ex vivo assays and animal models that accurately recapitulate the disease. Thus, we have developed a standardised whole-tissue explant model of HS to examine its pathogenic mechanisms and the efficacy of potential treatments within intact human tissue. We measured cytokine protein and RNA within whole tissue maintained in an agar-media solution, finding that IL-6 and IL-8 concentrations trended upwards in both HS explants and healthy controls, while IL-17A, IL-1β, and TNF-α exhibited increases in HS tissue alone. We also show that the explants were responsive to treatment with both dexamethasone and IL-2. Not only do our results show that this model effectively delivers treatments throughout the explants, but they also elucidate which cytokines are related to the explant process regardless of tissue state and which are related to HS tissue specifically, laying the groundwork for future implementations of this model.

Activated and Naïve Allogenic Human Placental Mesenchymal Stromal Cells Exert an Immunomodulatory Effect on Hidradenitis Suppurativa Patient Peripheral Blood Mononuclear Cells

This pilot study aimed to evaluate the immunomodulatory effect of placental mesenchymal stem/stromal cells (MSCs) on peripheral blood mononuclear cells (PBMCs) from patients with hidradenitis suppurativa (HS). Blood samples were collected from 3 healthy and 3 patients with HS. Isolated PBMCs were stained with carboxyfluorescein succinimidyl ester (CFSE) and stimulated with phorbol 12-myristate 13-acetate (PMA)/Ionomycin solution. The PBMCs of patients with HS were co-cultured with naïve MSCs (n-MSCs), activated with tumor necrosis factor (TNF)-α (10 ng/mL) and interferon (IFN)-γ (10 ng/mL) MSCs (a-MSCs), or adalimumab (30 μg/mL). The division index (proliferation inhibition) of PBMCs was analyzed by flow cytometry using the Proliferation Modeling tool after 5 days of coculture. The relative inflammatory gene expression dynamics and cytokine secretion were quantified in triplicate using real-time polymerase chain reaction (PCR) and Luminex assays. PBMCs from the HS control group showed statistically significant increases in interleukin (IL)-6 and IFN-γ cytokine concentrations and IL-17A gene expression when compared with healthy subjects. Statistically significant reduction of the division index was found in the a-MSCs group (P = 0.04). Also, the Luminex assay revealed significantly reduced proinflammatory cytokine concentrations of IL-9 (P = 0.022) and IL-17A (P = 0.022) in the a-MSCs group with the same trend of numerical lowering in n-MSCs group when compared to HS control. The results of real-time PCR revealed a numerical increase in the expression of the IL-1β, IL-36α, and TNF-α genes in both the a-MSCs and n-MSCs groups compared with the HS control. In conclusion, our findings suggest that MSCs can effectively curb PBMCs proliferation and suppress the production of inflammatory cytokines. Moreover, the preactivation of MSCs with IFN-γ and TNF-α before use can enhance their therapeutic effectiveness. Nevertheless, a larger sample size is imperative to validate these results.

Risk of dyslipidemia and major adverse cardiac events with tofacitinib versus adalimumab in rheumatoid arthritis: a real-world cohort study from 7580 patients

Objective

To compare the effects of tofacitinib and adalimumab on the risk of adverse lipidaemia outcomes in patients with newly diagnosed rheumatoid arthritis (RA).

Methods

Data of adult patients newly diagnosed with RA who were treated with tofacitinib or adalimumab at least twice during a 3-year period from 1 January 2018 to 31 December 2020, were enrolled in the TriNetX US Collaborative Network. Patient demographics, comorbidities, medications, and laboratory data were matched by propensity score at baseline. Outcome measurements include incidental risk of dyslipidemia, major adverse cardiac events (MACE) and all-cause mortality.

Results

A total of 7,580 newly diagnosed patients with RA (1998 receiving tofacitinib, 5,582 receiving adalimumab) were screened. After propensity score matching, the risk of dyslipidaemia outcomes were higher in the tofacitinib cohort, compared with adalimumab cohort (hazard ratio [HR] with 95% confidence interval [CI], 1.250 [1.076-1.453]). However, there is no statistically significant differences between two cohorts on MACE (HR, 0.995 [0.760-1.303]) and all-cause mortality (HR, 1.402 [0.887-2.215]).

Conclusion

Tofacitinib use in patients with RA may increase the risk of dyslipidaemia to some extent compared to adalimumab. However, there is no differences on MACE and all-cause mortality.