Epicutaneous Application Research Articles

Epicutaneous house dust mite (HDM)-induced skin lesions feature early activation of T helper 2 inflammatory and pruritogenic pathways in HDM-nonsensitised dogs.

Epicutaneously house dust mite-sensitised (HDM-S) healthy dogs are commonly used as canine atopic dermatitis (cAD) models; however, the exact mechanisms of HDM-induced AD immune activation in HDM-S and HDM-nonsensitised (NS) dogs remain unclear. To characterise the inflammatory and pruritogenic transcriptome of acute epicutaneous HDM-induced skin lesions at 6 h and 24 h in HDM-NS and HDM-S dogs; untreated skin at 0 h from each dog served as control. Six HDM-S and six HDM-NS laboratory beagles. Processed expression data from GEO deposited by Schamber etal. (G3 (Bethesda), 2014, 4 and 1787) (GSE58442) were downloaded and analysed using R and the Bioconductor package. Significance analysis was performed with the limma package; genes with false discovery rate <0.05 and fold-change ≤/≥1.5 were considered significantly differentially expressed (DEGs). A 2D principal component analysis revealed no clear separation between HDM-NS and HDM-S dogs at 6 h and 24 h time points. HDM-induced skin lesions in sensitised and nonsensitised dogs at the 24 h time point showed significant upregulation of T helper cell (Th)2 genes (interleukin [IL]-4R, IL-5, IL-13, CCL13 and CCL17), as well as proinflammatory- (LTB, IL-1A and IL-18), Th1- (CXCL10, OASL and MX-1) and Th17-related markers (IL-17B, IL-17F, CCL19 and CCL20). The key Th22-related maker, IL-22, was upregulated only in the HDM-S group at the 24 h time point. Both groups at 24 h featured significant upregulation of several noncytokine pruritogens, such as trypsin, chymase, cathepsin S, periostin and neuromedin B. Taken together, we establish that epicutaneous HDM patch application induces immune changes in HDM-NS dogs with Th2 dominance and activates several itch-promoting pathways.

Malassezia globosa Induces Differentiation of Pathogenic Th17 Cells by Inducing IL-23 Secretion by Keratinocytes.

Malassezia, the most abundant fungal commensal on the mammalian skin, has been linked to several inflammatory skin diseases such as atopic dermatitis, seborrheic dermatitis and psoriasis. This study reveals that epicutaneous application with Malassezia globosa (M. globosa) triggers skin inflammation in mice. RNA-sequencing of the resulting mouse lesions indicates activation of Interleukin-17 (IL-17) signaling and T helper 17 (Th17) cells differentiation pathways by M. globosa. Furthermore, our findings demonstrate a significant upregulation of IL-23, IL-23R, IL-17A, and IL-22 expressions, along with an increase in the proportion of Th17 and pathogenic Th17 cells in mouse skin exposed to M. globosa. In vitro experiments illustrate that M. globosa prompts human primary keratinocytes to secrete IL-23 via TLR2/MyD88/NF-κB signaling. This IL-23 secretion by keratinocytes is shown to be adequate for inducing the differentiation of pathogenic Th17 cells in the skin. Overall, these results underscore the significant role of Malassezia in exacerbating skin inflammation by stimulating IL-23 secretion by keratinocytes and promoting the differentiation of pathogenic Th17 cells.

Impact of Skin Exposure to Benzo[a]pyrene in Rat Model: Insights into Epidermal Cell Function and Draining Lymph Node Cell Response.

The skin is a direct target of the air pollutant benzo[a]pyrene (BaP). While its carcinogenic qualities are well-studied, the immunotoxicity of BaP after dermal exposure is less understood. This study examines the immunomodulatory effects of a 10-day epicutaneous BaP application, in environmentally/occupationally relevant doses, by analyzing ex vivo skin immune response (skin explant, epidermal cells and draining lymph node/DLN cell activity), alongside the skin's reaction to sensitization with experimental hapten dinitrochlorobenzene (DNCB). The results show that BaP application disrupts the structure of the epidermal layer and promotes immune cell infiltration in the dermis. BaP exposure led to oxidative stress in epidermal cells, characterized by decreased reduced glutathione and increased AHR and Cyp1A1 expression. Production and gene expression of proinflammatory cytokines (TNF, IL-1β) by epidermal cells decreased, while IL-10 response increased. Decreased spontaneous production of IFN-γ and IL-17, along with unchanged IL-10, was observed in DLC cells, whereas ConA-stimulated production of these cytokines was elevated. Local immunosuppression caused by BaP application seems to reduce the skin's response to an additional stimulus, evidenced by decreased effector activity of DLN cells three days after sensitization with DNCB. These findings provide new insight into the immunomodulatory effects and health risks associated with skin exposure to BaP.

Topical application of a CCL22-binding aptamer suppresses contact allergy

Allergic contact dermatitis is a prevalent occupational disease with limited therapeutic options. The chemokine CCL22, a ligand of the chemokine receptor CCR4, directs the migration of immune cells. Here, it is shown that genetic deficiency of CCL22 effectively ameliorated allergic reactions in contact hypersensitivity (CHS), a commonly used mouse model of allergic contact dermatitis. For pharmacological inhibition of CCL22, DNA aptamers specific for murine CCL22 were generated by systematic evolution of ligands by exponential enrichment (SELEX). Nine CCL22-binding aptamers were initially selected and functionally tested in vitro. The 29-nucleotide DNA aptamer AJ102.29m profoundly inhibited CCL22-dependent T cell migration and did not elicit undesired Toll-like receptor-dependent immune activation. AJ102.29m efficiently ameliorated CHS in vivo after systemic application. Moreover, CHS-associated allergic symptoms were also reduced following topical application of the aptamer on the skin. Microscopic analysis of skin treated with AJ102.29m ex vivo demonstrated that the aptamer could penetrate into the epidermis and dermis. The finding that epicutaneous application of the aptamer AJ102.29m in a cream was as effective in suppressing the allergic reaction as intraperitoneal injection paves the way for therapeutic use of aptamers beyond the current routes of systemic administration.

Hygienic characteristics of ethanol for preventive use in skin antiseptics

Aim – to study the ethyl alcohol 70% of the Lux brand in respect to its chemical and analytical quality, toxicological safety, microbial effectiveness and to assess its use in skin antiseptics. Material and methods. The studies were performed using organoleptic, physical, chemical, toxicological and microbial analysis in accordance with standard modern methods. Results. Ethyl alcohol 70% has chemical, analytical and microbial quality indicators that meet the requirements of the State Pharmacopeia of the Republic of Belarus. According to toxicological indicators, it belongs to class IV – lowhazard substances, with no irritating effect, which corresponds to the regulatory toxicological indicators of the safety of skin antiseptics. During the primary epicutaneous application on volunteers, it does not cause subjective and objective symptoms of sensitization; it belongs to substances that do not have an irritating effect and sensitizing ability. Standard test cultures and clinical strains of microorganisms are highly sensitive to ethyl alcohol 70% in a qualitative suspension test tube and micromethod without protein load and moderately sensitive in the diskdiffusion method with an exposure of 1 min. In relation to these microorganisms, the antimicrobial activity of ethyl alcohol 70% is above 99.999% and a reduction factor above 5 lg at exposure of 1 min in a quantitative suspension method without a protein load. Ethyl alcohol 70% is also characterized by a high efficiency of normal skin disinfection and E.coli contaminated skin of volunteers over 99% and a reduction factor above 2 lg and 4 lg, respectively. Conclusion. Ethyl alcohol 70% of the brand "Lux" is a highquality, toxicologically safe and microbial effective drug. It can be recommended for skin antisepsis of the injection field (class A), as well as hygienic hand antisepsis (class B) and antiseptic sanitization of the skin in the Republic of Belarus and Russian Federation.

Forward genetics and functional analysis highlight Itga11 as a modulator of murine psoriasiform dermatitis.

Psoriasis is a chronic inflammatory skin condition. Repeated epicutaneous application of Aldara® (imiquimod) cream results in psoriasiform dermatitis in mice. The Aldara®-induced psoriasiform dermatitis (AIPD) mouse model has been used to examine the pathogenesis of psoriasis. Here, we used a forward genetics approach in which we compared AIPD that developed in 13 different inbred mouse strains to identify genes and pathways that modulated disease severity. Among our primary results, we found that the severity of AIPD differed substantially between different strains of inbred mice and that these variations were associated with polymorphisms in Itga11. The Itga11 gene encodes the integrin α11 subunit that heterodimerizes with the integrin β1 subunit to form integrin α11β1. Less information is available about the function of ITGA11 in skin inflammation; however, a role in the regulation of cutaneous wound healing, specifically the development of dermal fibrosis, has been described. Experiments performed with Itga11 gene-deleted (Itga11-/- ) mice revealed that the integrin α11 subunit contributes substantially to the clinical phenotype as well as the histopathological and molecular findings associated with skin inflammation characteristic of AIPD. Although the skin transcriptomes of Itga11-/- and WT mice do not differ from one another under physiological conditions, distinct transcriptomes emerge in these strains in response to the induction of AIPD. Most of the differentially expressed genes contributed to extracellular matrix organization, immune system, and metabolism of lipids pathways. Consistent with these findings, we detected a reduced number of fibroblasts and inflammatory cells, including macrophages, T cells, and tissue-resident memory T cells in skin samples from Itga11-/- mice in response to AIPD induction. Collectively, our results reveal that Itga11 plays a critical role in promoting skin inflammation in AIPD and thus might be targeted for the development of novel therapeutics for psoriasiform skin conditions. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Human NCF190H Variant Promotes IL-23/IL-17-Dependent Mannan-Induced Psoriasis and Psoriatic Arthritis.

Recently, a major single nucleotide variant on the NCF1 gene, leading to an amino acid replacement from arginine to histidine at position 90 (NCF1R90H), associated with low production of reactive oxygen species (ROS), was found to be causative for several autoimmune diseases. Psoriasis in the skin (PsO) and psoriatic arthritis (PsA) were induced with mannan by intraperitoneal injection or epicutaneous application, evaluated by visual and histology scoring. Immunostaining was used to identify macrophages, NCF1, and keratinocytes. The population of immune cells was quantified by flow cytometry, gene expression was analyzed by RT-qPCR, and the JAK/STAT signaling pathway was investigated by immunohistochemical staining and western blot. We found that the low ROS responder NCF190H variant promotes PsO and PsA (the MIP model). The NCF190H-expressing mice had hyperactivated macrophages, expanded keratinocytes, and dramatically increased numbers of γδT17 cells with upregulated IL-17A, IL-23, and TNF-α. In addition, the JAK1/STAT3 signaling pathway was also upregulated in cells in the psoriatic skin tissues of Ncf190H mice. To summarize, a defined SNP (NCF1-339, also named NCF190H) was found to activate the IL-23/IL-17 axis and JAK-STAT signaling pathways, leading to hyperactivation of macrophages and keratinocytes and causing mouse psoriasis and psoriatic arthritis.

Butyrate inhibits Staphylococcus aureus-aggravated dermal IL-33 expression and skin inflammation through histone deacetylase inhibition.

Atopic dermatitis (AD) is an inflammatory skin disease caused by the disruption of skin barrier, and is dominated by the type 2 immune responses. Patients with AD have a high risk of developing Staphylococcus aureus infection. Interleukin-33 (IL-33), an alarmin, has been implicated in the pathophysiology of AD development. Butyrate, a short chain fatty acid known to be produced from the fermentation of glycerol by the commensal skin bacterium, Staphylococcus epidermidis, has been reported to possess antimicrobial and anti-inflammatory properties that suppress inflammatory dermatoses. However, little is known about the effects of butyrate on dermal IL-33 expression and associated immune response in S. aureus-aggravated skin inflammation in the context of AD. To decipher the underlying mechanism, we established an AD-like mouse model with epidermal barrier disruption by delipidizing the dorsal skin to induce AD-like pathophysiology, followed by the epicutaneous application of S. aureus and butyrate. We discovered that S. aureus infection exacerbated IL-33 release from keratinocytes and aggravated dermal leukocyte infiltration and IL-13 expression. Moreover, we showed that butyrate could attenuate S. aureus-aggravated skin inflammation with decreased IL-33, IL-13, and leukocyte infiltration in the skin. Mechanistically, we demonstrated that butyrate suppressed IL-33 expression and ameliorated skin inflammation through histone deacetylase 3 (HDAC3) inhibition. Overall, our findings revealed the potential positive effect of butyrate in controlling inflammatory skin conditions in AD aggravated by S. aureus infection.

Permethrin Steal Effect by Unmasked Corneocytic Keratin in Topical Therapy of Scabies

Introduction: The use of epicutaneously applied permethrin in the treatment of common scabies is considered to be the first-line therapy. Due to increasing clinical treatment failure, the development of genetic resistance to permethrin in Sarcoptes scabiei var. hominis has been postulated. In addition, metabolic resistance and pharmacokinetic limitations by parasitic digestion and reactive thickening of stratum corneum are suspected to cause a reduction in cutaneous bioavailability. Methods: Since lipophilic permethrin is known to form hydrophobic interactions with proteins via van der Waals interactions, a similar interaction was assumed and investigated for permethrin and the protein keratin. Using keratin particles extracted from animal material, a model for hyperkeratotic and parasitic digested scabies skin was developed. Using fluorescence-labeled keratin and ³H-permethrin, their interaction potential was validated by loading and unloading experiments. Additionally, the impact of keratin to permethrin penetration was investigated based on an in vitro model using Franz diffusion cells. Results: For the first time, keratin particles were introduced as a model for dyskeratotic skin, as we were able to show, the keratin particles’ interaction potential with permethrin but no penetration behavior into the stratum corneum. Moreover, comparative penetration experiments of a reference formulation with and without added keratin or keratin-adherent permethrin showed that keratin causes a steal effect for permethrin, leading to a relevant reduction in cutaneous bioavailability in the target compartment. Conclusion: The results provide further evidence for a relevant pharmacokinetic influencing factor in the epicutaneous application of permethrin and a rationale for the necessity of keratolytic pretreatment in hyperkeratotic skin for the effective use of topical permethrin application in scabies.

Epicutaneous Immunotherapy with CBir1 Alleviates Intestinal Inflammation.

Inflammatory bowel disease may be due to failed tolerance to normal gut bacteria. We demonstrate that epicutaneous immunotherapy (ET) to ovalbumin can alleviate colitis in murine models. However, most people are tolerant to or have anergy to ovalbumin. Half of Crohn's disease (CD) patients have CBir1 antibodies that can be elevated years before CD development. We determined whether ET with a CBir1 multi-epitope peptide (MEP1) could alleviate colitis. Wild type mice (C57BL/6) were transferred with CBir1 T cell receptor (TCR) T cells followed by epicutaneous application of MEP1. Proliferating Foxp3+ T cells were measured in mesenteric lymph nodes (LNs), spleen, small intestine, and colon by flow cytometry. Lymphocytes from MEP1 epicutaneously exposed and immunized C57BL/6 mice were cultured with MEP1. Interferon (IFN)-γ production was measured. Colitis was induced by transferring CD4+CD45Rbhi T cells from CBIR1 TCR or C57BL/6 mice into RAG1-/- mice. Mice were treated with ET. Body weight, colon length, colonic cytokine production, histological inflammation, inflammatory genes, and regulatory T cells (Tregs) from lamina propria were measured. ET with 10 μg of MEP1 induced CBir1-specific Tregs that migrated to the small intestine and colon and suppressed MEP1-specific IFN-γ production. ET alleviated colitis when the model utilized CBir1 TCR T cells in mice colonized with CBir1 or A4Fla2 positive bacteria. Treated mice had improved colon length and histological inflammation and reduced colonic IFN-γ production. Epicutaneous immunotherapy with MEP1 induced Tregs that migrate to intestines and suppress inflammation in mice with CBir1 or A4Fla2-positive bacterial colonization. This could be a potential strategy to treat CD and warrants further study.

Epicutaneous Application of Mannan Induces Psoriasis-like Inflammation in an Inbred Mouse Strain.

Mannan from yeast induces psoriasis-like inflammation in the skin of inbred mouse strains. Limitations of available models led us to develop a new psoriasis model with a rapid disease onset, severe disease course, short duration, and a simple and easy-to-induce protocol with much more practically convenient features and cost-benefits. Mannan-induced skin inflammation (MISI) is more severe than the classical imiquimod (IMQ)-induced skin inflammation (IISI), with characteristic features resembling human plaque psoriasis but with relatively fewer toxicity issues. Epicutaneous application of mannan (5 mg) in incomplete Freund's adjuvant or Vaseline induces severe psoriasis in BALB/c female mice. Psoriasis area and severity index (PASI) and histological evaluation of the skin could help assess the disease development. MISI mimics natural environmental factors affecting the skin relatively more closely than IISI. This disease model can be used to dissect inflammatory pathways in the skin, identify genetic and environmental factors affecting psoriasis, and test potential pharmacological agents or new combinations of available drugs for treatment before designing clinical trials. Key features • S. cerevisiae mannan induces psoriasis-like skin inflammation (MISI) when applied on the skin of inbred mice. • The MISI model has a rapid onset, severe disease, short duration, and simple and easy-to-induce protocol. • MISI is more severe than imiquimod-induced skin inflammation (IISI). • Female mice had a more severe disease than males in the MISI model, thereby allowing the study of sex-dependent disease mechanisms. • The MISI model identifies skin inflammatory pathways and genetic/environmental factors affecting psoriasis. • The MISI model can be used as a drug testing platform for potential pharmaceuticals to develop new therapeutics for psoriasis patients. • The MISI model can be used to explore the relative contribution of different pattern recognition receptors in the development and severity of psoriasis.

The extrafollicular response is sufficient to drive initiation of autoimmunity and early disease hallmarks of lupus.

Many autoimmune diseases are characterized by germinal center (GC)-derived, affinity-matured, class-switched autoantibodies, and strategies to block GC formation and progression are currently being explored clinically. However, extrafollicular responses can also play a role. The aim of this study was to investigate the contribution of the extrafollicular pathway to autoimmune disease development. We blocked the GC pathway by knocking out the transcription factor Bcl-6 in GC B cells, leaving the extrafollicular pathway intact. We tested the impact of this intervention in two murine models of systemic lupus erythematosus (SLE): a pharmacological model based on chronic epicutaneous application of the Toll-like receptor (TLR)-7 agonist Resiquimod (R848), and 564Igi autoreactive B cell receptor knock-in mice. The B cell intrinsic effects were further investigated in vitro and in autoreactive mixed bone marrow chimeras. GC block failed to curb autoimmune progression in the R848 model based on anti-dsDNA and plasma cell output, superoligomeric DNA complexes, and immune complex deposition in glomeruli. The 564Igi model confirmed this based on anti-dsDNA and plasma cell output. In vitro, loss of Bcl-6 prevented GC B cell expansion and accelerated plasma cell differentiation. In a competitive scenario in vivo, B cells harboring the genetic GC block contributed disproportionately to the plasma cell output. We identified the extrafollicular pathway as a key contributor to autoimmune progression. We propose that therapeutic targeting of low quality and poorly controlled extrafollicular responses could be a desirable strategy to curb autoreactivity, as it would leave intact the more stringently controlled and high-quality GC responses providing durable protection against infection.

Establishing an experimental model for canine atopic dermatitis through epicutaneous application of Dermatophagoides farinae.

There is no established protocol for the development of an experimental canine atopic dermatitis model in laboratory beagles. This study aimed to establish an experimental model that mimics spontaneous canine atopic dermatitis (CAD) clinically, immunologically, and microbiologically, by repeated epicutaneous applications of mite antigens and to describe the entire process including sensitization and provocation in detail for reproducibility. Six intact male laboratory beagle dogs aged 14 months were included in this study. During the sensitization and provocation phase, the house dust mite (HDM) paste consisted of Dermatophagoides farinae (Der f ) and mineral oil, which was applied focally to the 10 × 10 cm area of the right groin as evenly as possible. Further, 120 mg of Der f was applied to each dog twice a week for 12 weeks during the sensitization phase and 25 mg and 120 mg was applied to each dog for the first 2 weeks and subsequent 2 weeks, respectively, during the provocation phase. Thereafter, the applied area was covered with a dressing. Skin lesions including erythema, hyperpigmentation, excoriation, and lichenification were induced and exacerbated gradually through the experimental time course in all six dogs. The canine atopic dermatitis extent and severity index (CADESI) score and transepidermal water loss (TEWL) significantly increased after sensitization and provocation. IL-13 and IL-31 levels increased significantly after provocation as a result of the activation of the T helper-2 (Th2) response. On the contrary, the IL-10 levels decreased significantly after sensitization, which suggested a suppression of Tregs activity. After the completion of provocation, skin microbiome analysis showed that Firmicutes was the most abundant phylum, which indicated bacterial dysbiosis. This study demonstrated that epicutaneous application of HDM in beagle dogs resulted in the elevation of serum HDM-specific IgE levels and clinical atopic scores, a high TEWL, and microbiome dysbiosis resembling spontaneous CAD. These results suggest that this tailored protocol of epicutaneous exposure to Der f may provide support for the development of the experimental CAD model in laboratory beagles.

An Atopic Dermatitis-Like Mouse Model by Alternate Epicutaneous Application of Dinitrofluorobenzene and an Extract of Dermatophagoides Farinae.

Several studies have tried to establish mice models of atopic dermatitis (AD) through the allergen of Dermatophagoides farinae (Df). However, there are no typical skin lesions after epicutaneous application of an extract of Df (DfE) on BALB/c mice. Dinitrofluorobenzene (DNFB) is a common hapten that brings about contact dermatitis. Skin dysfunction induced by DNFB may be a way to enhance the effects of DfE on mice skin. Thus, we hypothesized that alternate epicutaneous application of DNFB and DfE could induce AD-like skin lesions on BALB/c mice. To test this hypothesis, we alternately applied the DNFB and DfE to the back skin of BALB/c mice for 8 weeks. Changes in mice skin lesions and the frequency of scratching behavior were recorded. The variation of Th1-related cytokines (interferon-γ [IFN-γ] and interleukin two [IL-2]) and Th2-related cytokines (IL-4 and IL-13) was detected in serum and lesional skin. Eventually, the BALB/c mice developed severe erythema, erosion, scarring, and excoriation on the entire back, showing a high frequency of scratching behavior. In addition, Th2 cells' dominant cytokines appeared in both serum and lesional skin. Those results indicate that alternating epicutaneous exposure to DNFB and DfE can produce AD-like models with typical clinical features and Th2-type immune responses in BALB/c mice. This model could be valuable for studying the pathogenesis of AD and developing novel therapeutic agents for it.

AI/ML‐driven simulation of the skin retention of opioid analgesics following topical administration in normal skin and cutaneous lesions

Topical drug administration in the treatment of skin disorders is known to have high efficacy with a favorable safety profile in clinical settings. Disposition of the active pharmaceutical ingredient (API) in the skin layers plays a critical role for the dose regimen calculator required for desired therapy efficiency. Experimental measurements of the API skin concentration are complicated and inaccurate and can be replaced with physiologically based pharmacokinetic modeling predicting local and systemic drug exposure. Opioid analgesics are commonly used in treating severe pain and it is frequently associated with putative adverse effects. Topical applications of opioids were shown to have high efficacy with a favorable safety profile in clinical settings. Clinical investigations of transdermal drug formulations, especially in patients with skin lesions, are often hindered due to the patient intolerance, high cost of the studies, and ethical aspects.BIOiSIM, a hybrid artificial intelligence computational platform integrating machine learning optimization with mechanistic modeling was implemented to accurately simulate in vivo plasma concentration profile and predict partition coefficients and API skin retention for two opioid analgesics in healthy skin and simulated skin lesions. Publicly available drug parameters and physiological data were used for the model building.The platform successfully predicted API systemic exposure and skin concentration following the epicutaneous application of central opioid agonist buprenorphine and peripheral opioid agonist oxycodone in healthy human skin and simulated subjects impaired skin. Experimentally observed plasma concentration for both drugs demonstrated validity of the in‐silico methods. The results indicated that buprenorphine permeates rapidly through the stratum corneum and partitions into the dermis, where its concentration slowly declines as the reservoir in the compound vehicle is depleted. Thus, the impact of lesions is not as significant. In contrast, the hydrophilic oxycodone, where the rate‐limiting stratum corneum layer prevents a significant portion of the compound from permeating deeper in healthy patients. Hence, concentration of oxycodone sharply declines over the first hours of exposure in deeper indicating poorer accumulation capacity in the skin in the presence of lesions.An AI/ML‐driven PBPK model was applied for accurate simulation skin concentrations of two opioid analgesics – buprenorphine and oxycodone. The results have confirmed that both these drugs have good skin retention and can stimulate opioid receptors located in skin. The results suggest that buprenorphine showing substantial skin retention capacity can be applied topically for the treatment of skin disorders in in patients.

26775 Vancomycin-associated drug-induced hypersensitivity syndrome after IV therapy with vancomycin and implantation of a vancomycin-eluting spacer and absorbable beads

Drug-induced hypersensitivity syndrome (DIHS) is a life-threatening severe cutaneous adverse reaction with multisystem involvement. DIHS usually occurs in the context of orally or intravenously administered medications, but can be reactivated with epicutaneous application of culprit medications. We present a case of a 31-year-old woman who developed vancomycin-induced DIHS after treatment of a prosthetic joint infection. Her total hip arthroplasty prosthesis infection was treated with removal of the prosthesis, IV vancomycin and implantation of a polymethyl methacrylate vancomycin-eluting spacer along with vancomycin-eluting absorbable calcium beads. 26 days after treatment, she developed a pruritic morbilliform exanthema along with malaise, nausea, dysphagia, neck-swelling, chills and was noted to have an AST of 389 and an ALT of 338. IV vancomycin was replaced with daptomycin and patient was started on 100mg of daily prednisolone. After initiation of prednisolone, she had rapid improvement of her neck-swelling and rash, but her AST and ALT remained elevated for 10 days despite treatment with corticosteroids. Given her persistently elevated AST and ALT, multidisciplinary discussions were held to consider removing the implanted vancomycin-eluting spacer. Surgery was deferred due to the patient’s high dose corticosteroids, increased risk of infection and incremental clinical improvement. She continued to improve and eventually tapered off her steroids after discharge. This is the first reported case of DIHS in a patient treated with drug-eluting absorbable beads, implant and IV antibiotics. In conclusion, we recommend careful consideration of the relative risks and benefits along with close clinical monitoring before surgical revision in complex cases of DIHS.

Mdivi-1 alleviates atopic dermatitis through the inhibition of NLRP3 inflammasome.

Atopic dermatitis (AD) is a chronic inflammatory cutaneous disorder with few treatment options. Dynamin-related protein 1 (Drp1)-dependent mitochondrial fission contributes to the activation of NLRP3 inflammasome, and inhibiting Drp1has been become an attractive therapeutic strategy for inflammatory diseases. This study aimed to investigate the effects of Drp1 inhibitor mdivi-1 on experimental AD. We firstly detected the effects of mdivi-1 on primary human keratinocytes in an inflammatory cocktail-induced AD-related inflammation in vitro. Results showed that mdivi-1 inhibited NLRP3 inflammasome activation and pyroptosis which were evidenced by decreased expression of NLRP3, ASC, cleavage of caspase-1, GSDMD-NT, mature interleukin (IL)-1β and IL-18 in keratinocytes under AD-like inflammation. Next, mouse model of AD-like skin lesions was induced by epicutaneous application of 2,4-dinitrochlorobenzene (DNCB) and mdivi-1 (25mg/kg/day, days 5-33 during construction of AD model) was intraperitoneally injected into DNCB-induced mice. AD mice with mdivi-1 treatment exhibited ameliorated AD symptoms, lower serum IgE level, and reduced epidermal thickening, mast cells infiltration, and production of IL-4, IL-5 and IL-13 in the lesional tissues. Indeed, mdivi-1significantly inhibited NLRP3 inflammasome activation and pyroptotic injury occurred in DNCB-treated skin tissues. Mechanically, mdivi-1 regulated the expression of mitochondrial dynamic proteins and suppressed the activation of NF-κB signal pathway which is an upstream of NLRP3 inflammasome both in vitro and in vivo. This study demonstrated that mdivi-1 could protect against experimental AD through inhibiting the activation of NLRP3 inflammasome and subsequent inflammatory cytokine release, and mdivi-1might exert this function by inhibiting mitochondrial fission and subsequently blocking NF-κB pathway.

Pre-Existing Humoral Immunity Enhances Epicutaneously-Administered Allergen Capture by Skin DC and Their Migration to Local Lymph Nodes.

Due to its richness in antigen presenting cells, e.g., dendritic cells (DC), the skin has been identified as a promising route for immunotherapy and vaccination. Several years ago, a skin delivery system was developed based on epicutaneous patches allowing the administration of antigen through intact skin. Using mouse models, we have shown that epicutaneous allergen application leads to a rapid uptake and transport of allergen-positive cells to skin-draining lymph nodes (LN). This occurred primarily in animals previously sensitized to the same allergen. In that context, we sought to better understand the role of the specific preexisting immunity in allergen capture by skin DC and their subsequent migration to LN. Specifically, we investigated the role of humoral immunity induced by sensitization and the involvement of IgG Fc receptors (FcγR). Epicutaneous patches containing fluorescently-labeled ovalbumin (OVA) were applied to naïve mice that had previously received either sera or purified IgG isolated from OVA-sensitized mice. To investigate the involvement of FcγR, animals received 2.4G2 (anti-FcγRII/RIII) blocking antibody, 24 hours before patch application. Mice that received sera or purified IgG originating from OVA-sensitized mice showed an increase in the quantity of OVA-positive DC in skin and LN. Moreover, the blockade of FcγR reduced the number of OVA-positive DC in LN to a level similar to that observed in naïve animals. Overall, these results demonstrate that preexisting specific-IgG antibodies are involved in allergen capture by skin DC following EPIT through the involvement of antigen-specific IgG-FcγR.

A comparative study of efficacy of 1064-nm Q-switched Neodymium: YAG laser at sub photothermolytic fluence alone and in combination therapy with epicutaneous 20% azelaic acid and in sequential therapy with microdermabrasion in melasma in South India

Introduction: Melasma is a symmetric hyperpigmentary disorder defined by irregular light to brown macules over the face. Treating melasma is demanding and there is curiosity in anticipation of recent various therapeutic options like sub photothermolytic fluence – 1064-nm Q switched Nd:YAG laser (SPF-1064-nm-QSNdYL) with combinational and sequential therapies. Aim: To study and compare the therapeutic effect of SPF-1064-nm-QSNdYL alone and in combinational therapy with epicutaneous 20% Azelaic Acid and in sequential therapy with microdermabrasion in melasma in three study groups of 20 cases each. Materials and Methods: Sixty female cases identified as melasma were randomly segregated into three factions [group L(laser only) = 20 cases of melasma treated with SPF-1064-nm-QSNdYL at weekly intervals, group C (combinational) = 20 cases of melasma treated with twice daily epicutaneous application of 20% azelaic acid and SPF-1064-nm-QSNdYL at weekly intervals and group S (sequential) = 20 cases of melasma treated with Sequential therapy with microdermabrasion followed by SPF-1064-nm-QSNdYL once weekly as given in group L]. The study duration was of 12 weeks for each. The outcome to therapy was analyzed using melasma area and severity index scoring. Results: Convincing therapeutic response was noted in all the three factions. It was statistically highly significant in Group C as compared to Group L (P 0.05). Conclusions: This study highlights the superior therapeutic effect of combinational therapy using SPF-1064-nm- QSNdYL with azelaic acid in epidermal, dermal and mixed types of melasma with minimal adverse effects followed by sequential therapy of microdermabrasion with SPF-1064-nm- QSNdYL and SPF-1064-nm- QSNdYL alone therapy. Keywords: Azelaic acid, SPF-1064-nm-QSNdYL, Microdermabrasion, Melasma.

Zaburzenia snu w stwardnieniu rozsianym

Abstrakt&#x0D; Stwardnienie rozsiane (sclerosis multiplex, SM) to schorzenie autoimmunologiczne, w którym limfocyty, autoreaktywne względem antygenów komórek nerwowych, naciekają ośrodkowy układ nerwowy i prowadzą do jego uszkodzenia. Stan ten doprowadza u osoby chorej do postępującego w sposób ciągły lub rzutami, pogarszania funkcji fizycznych, poznawczych, emocjonalnych oraz społecznych. U 43-67% chorych na SM obserwuje się nieprawidłowości związane ze snem, związane z bezsennością, zaburzeniami rytmu dobowego, oraz pojawiające się w następstwie zaburzeń ruchowych oraz zaburzeń oddychania. Zaburzenia te mogą pogarszać przebieg SM, jak i SM może pogarszać i zwiększać prawdopodobieństwo wystąpienia zaburzeń snu. Ta dwukierunkowa zależność związana jest z istotną rolą układu immunologicznego zarówno w patogenezie SM, jak i zaburzeń snu.&#x0D; W przygotowanym artykule przeglądowym przedstawiamy najnowsze informacje dotyczące etiologii i roli układu immunologicznego w SM oraz immunopatomechanizmu tego schorzenia, zwracając szczególną uwagę na współistniejące zaburzenia snu. W dalszej części omawiane są metody terapeutyczne SM, ze szczególnym uwzględnieniem naskórnej aplikacji antygenu białkowego, które oprócz ograniczenia postępu choroby potencjalnie mogą prowadzić do ograniczenia współistniejących zaburzeń snu.&#x0D;