Dupilumab as an adjuvant treatment for keloid-associated symptoms

Revisiting roles of mast cells and neural cells in keloid: exploring their connection to disease activity

Background

Mast cells (MCs) and neural cells (NCs) are important in a keloid microenvironment. They might contribute to fibrosis and pain sensation within the keloid. However, their involvement in pathological excessive scarring has not been adequately explored.

Objectives

To elucidate roles of MCs and NCs in keloid pathogenesis and their correlation with disease activity.

Methods

Keloid samples from chest and back regions were analyzed. Single-cell RNA sequencing (scRNA-seq) was conducted for six active keloids (AK) samples, four inactive keloids (IK) samples, and three mature scar (MS) samples from patients with keloids.

Results

The scRNA-seq analysis demonstrated notable enrichment of MCs, lymphocytes, and macrophages in AKs, which exhibited continuous growth at the excision site when compared to IK and MS samples (P = 0.042). Expression levels of marker genes associated with activated and degranulated MCs, including FCER1G, BTK, and GATA2, were specifically elevated in keloid lesions. Notably, MCs within AK lesions exhibited elevated expression of genes such as NTRK1, S1PR1, and S1PR2 associated with neuropeptide receptors. Neural progenitor cell and non-myelinating Schwann cell (nmSC) genes were highly expressed in keloids, whereas myelinating Schwann cell (mSC) genes were specific to MS samples.

Conclusions

scRNA-seq analyses of AK, IK, and MS samples unveiled substantial microenvironmental heterogeneity. Such heterogeneity might be linked to disease activity. These findings suggest the potential contribution of MCs and NCs to keloid pathogenesis. Histopathological and molecular features observed in AK and IK samples provide valuable insights into the mechanisms underlying pain and pruritus in keloid lesions.

Identification and validation of CCR5 linking keloid with atopic dermatitis through comprehensive bioinformatics analysis and machine learning

There is sufficient evidence indicating that keloid is strongly associated with atopic dermatitis (AD) across ethnic groups. However, the molecular mechanism underlying the association is not fully understood. The aim of this study is to discover the underlying mechanism of the association between keloid and AD by integrating comprehensive bioinformatics techniques and machine learning methods. The gene expression profiles of keloid and AD were downloaded from the Gene Expression Omnibus (GEO) database. A total of 449 differentially expressed genes (DEGs) were found to be shared in keloid and AD using the training datasets of GEO (GSE158395 and GSE121212). The hub genes were identified using the protein-protein interaction network and Cytoscape software. 20 of the most significant hub genes were selected, which were mainly involved in the regulation of the inflammatory and immune response. Through two machine learning algorithms of LASSO and SVM-RFE, CCR5 was identified as the most important key gene. Subsequently, upregulated CCR5 gene expression was confirmed in validation GEO datasets (GSE188952 and GSE32924) and clinical samples of keloid and AD. Immune infiltration analysis showed that T helper (Th) 1, 2 and 17 cells were significantly enriched in the microenvironment of both keloid and AD. Positive correlations were found between CCR5 and Th1, Th2 and Th17 cells. Finally, two TFs of CCR5, NR3C2 and YY1, were identified, both of which were downregulated in keloid and AD tissues. Our study firstly reveals that keloid and AD shared common inflammatory and immune pathways. Moreover, CCR5 plays a key role in the pathogenesis association between keloid and AD. The common pathways and key genes may shed light on further mechanism research and targeted therapy, and may provide therapeutic interventions of keloid with AD.

Pruritus in keloid scars: mechanisms and treatments

Keloids occur after cutaneous injury and can cause distress due to physical appearance and associated symptoms such as pain and pruritus. Keloid-associated pruritus is a common manifestation and has negative impacts on quality of life. The mechanism underlying this type of pruritus is multifactorial and thought to involve small nerve fiber damage, neurogenic inflammation, and a Th2-predominant inflammatory response. Various agents have been shown to reduce keloid pruritus, including intralesional corticosteroids, botulinum toxin A, 5-fluorouracil, and bleomycin. Other treatment modalities such as cryotherapy and hyperbaric oxygen therapy are also effective. Future treatments targeting the mechanisms involved in keloid-associated itch could provide improvements in pruritus and quality of life in these patients, but further studies on the efficacy of these agents are needed.

Tissue RNA Sequencing Reveals Novel Biomarkers Associated with Postoperative Keloid Recurrence

Keloids can be resected through surgery, but they may still recur. The purpose of this study was to explore the biomarkers to predict the postoperative recurrence of keloids. Patients who underwent surgical treatment and postoperative superficial X-ray radiation between January 2019 and December 2020 were recruited with clinical data and keloid samples for RNA-seq. By screening differentially expressed genes (DEGs) between postoperative recurrent and non-recurrent sample groups and constructing a co-expression network via the weighted gene co-expression network analysis (WGCNA), an immunity-related module was chosen for subsequent analysis. By constructing a DEG co-expression network and using the Molecular Complex Detection (MCODE) algorithm, five hub genes were identified in the key module. Receiver Operating Characteristic (ROC) curve analysis showed that the area under the curve (AUC) for the five combined hub genes was 0.776. The result of qRT-PCR showed that CHI3L1, IL1RN, MMP7, TNFAIP3, and TNFAIP6 were upregulated in the recurrent group with statistical significance (p < 0.05). Immune infiltration analysis showed that mast cells, macrophages, and T cells were the major components of the keloid immune microenvironment. This study provides potential biomarkers for predicting keloid recurrence and offers insights into genetic targets for recurrence prevention.

Evidence-based management of keloids and hypertrophic scars in dermatology

While normal, controlled wound-healing results in scars that are nearly imperceptible, hypertrophic scars (HTS) and keloids are the result of an abnormal wound-healing process that can leave unsightly, difficult-to-treat lesions. While such scars are classically associated with surgical incisions, they may also result from burns or accidental trauma to the skin. Several different measures can be taken to prevent the formation of scars or treat those that have already formed. Prevention focuses on reducing inflammation during the wound-healing process, and minimizing tension in the lesion when appropriate. Treatments range from non-invasive modalities such as pressure therapy, topicals, and symptom management, to invasive methods such as injections, lasers, and even surgery. While some treatments, such as corticosteroid injections, have been used in the treatment of HTS and keloids for decades, other newer therapies have only been described in case reports or are still in early phases of clinical trials. Because optimal scar management will not be the same for every patient, further investigation of newer agents and methods is warranted and may benefit a great number of patients. This paper will review the evidence-based management of scars, including current widely used treatment options and promising newly emerging therapies.

Dupilumab in Inflammatory Skin Diseases: A Systematic Review

Dupilumab was first approved for the treatment of atopic dermatitis (AD) and blocks the signaling of interleukin (IL)-4 and -13. Several other chronic skin conditions share mechanistic overlaps with AD in their pathophysiology, i.e., are linked to type 2 inflammation. Most recently, dupilumab was approved by the U.S. Food and Drug Administration for prurigo nodularis (PN). Given its relatively good safety profile, effective off-label use of dupilumab has been reported for a multitude of dermatologic diseases and several clinical trials for dermatologic skin conditions are currently ongoing. We conducted a systematic review of applications of dupilumab in dermatology other than AD and PN by searching the databases PubMed/Medline, Scopus, Web of Science and Cochrane Library as well as the clinical trial registry ClinicalTrials.gov. We found several reports for effective treatment of bullous autoimmune diseases, eczema, prurigo, alopecia areata, chronic spontaneous urticaria, Netherton syndrome and a variety of other chronic inflammatory skin diseases.

Hypertrophic Scars and Keloids: Advances in Treatment and Review of Established Therapies

Hypertrophic scars and keloids can have significant detrimental effects on patients both psychosocially and functionally. A careful identification of patient risk factors and a comprehensive management plan are necessary to optimize outcomes. Patients with a history of dystrophic scarring should avoid unnecessary procedures and enhance the wound-healing process using various preventive strategies. As there is no single, fully efficacious treatment modality, prevention remains the best approach in reducing aberrant scar formation. When prevention therapies fail, keloids have been shown to be respond to a variety of therapies including topical and injectable corticosteroids, 5-fluorouracil, radiotherapy, lasers, and surgical excision, all with varying efficacies. As such, management should be tailored to the individual patient's risk factors with the use of combination therapies to reduce recurrence rates. Still, keloid and hypertrophic scar therapies are widely diverse with novel treatment modalities providing alternatives for recurring lesions. Laser-assisted drug delivery, skin priming, and novel topical therapies may provide alternative options for the management of hypertrophic scars and keloids.

Comorbidities of Keloid and Hypertrophic Scars Among Participants in UK Biobank

Importance

Keloids and hypertrophic scars (excessive scarring) are relatively understudied disfiguring chronic skin conditions with high treatment resistance.

Objective

To evaluate established comorbidities of excessive scarring in European individuals, with comparisons across ethnic groups, and to identify novel comorbidities via a phenome-wide association study (PheWAS).

Design, Setting, and Participants

This multicenter cross-sectional population-based cohort study used UK Biobank (UKB) data and fitted logistic regression models for testing associations between excessive scarring and a variety of outcomes, including previously studied comorbidities and 1518 systematically defined disease categories. Additional modeling was performed within subgroups of participants defined by self-reported ethnicity (as defined in UK Biobank). Of 502 701 UKB participants, analyses were restricted to 230078 individuals with linked primary care records.

Exposures

Keloid or hypertrophic scar diagnoses.

Main Outcomes and Measures

Previously studied disease associations (hypertension, uterine leiomyoma, vitamin D deficiency, atopic eczema) and phenotypes defined in the PheWAS Catalog.

Results

Of the 972 people with excessive scarring, there was a higher proportion of female participants compared with the 229 106 controls (65% vs 55%) and a lower proportion of White ethnicity (86% vs 95%); mean (SD) age of the total cohort was 64 (8) years. Associations were identified with hypertension and atopic eczema in models accounting for age, sex, and ethnicity, and the association with atopic eczema (odds ratio [OR], 1.68; 95% CI, 1.36-2.07; P < .001) remained statistically significant after accounting for additional potential confounders. Fully adjusted analyses within ethnic groups revealed associations with hypertension in Black participants (OR, 2.05; 95% CI, 1.13-3.72; P = .02) and with vitamin D deficiency in Asian participants (OR, 2.24; 95% CI, 1.26-3.97; P = .006). The association with uterine leiomyoma was borderline significant in Black women (OR, 1.93; 95% CI, 1.00-3.71; P = .05), whereas the association with atopic eczema was significant in White participants (OR, 1.68; 95% CI, 1.34-2.12; P < .001) and showed a similar trend in Asian (OR, 2.17; 95% CI, 1.01-4.67; P = .048) and Black participants (OR, 1.89; 95% CI, 0.83-4.28; P = .13). The PheWAS identified 110 significant associations across disease systems; of the nondermatological, musculoskeletal disease and pain symptoms were prominent.

Conclusions and Relevance

This cross-sectional study validated comorbidities of excessive scarring in UKB with comprehensive coverage of health outcomes. It also documented additional phenome-wide associations that will serve as a reference for future studies to investigate common underlying pathophysiologic mechanisms.

An updated review of the immunological mechanisms of keloid scars

Keloid is a type of disfiguring pathological scarring unique to human skin. The disorder is characterized by excessive collagen deposition. Immune cell infiltration is a hallmark of both normal and pathological tissue repair. However, the immunopathological mechanisms of keloid remain unclear. Recent studies have uncovered the pivotal role of both innate and adaptive immunity in modulating the aberrant behavior of keloid fibroblasts. Several novel therapeutics attempting to restore regulation of the immune microenvironment have shown variable efficacy. We review the current understanding of keloid immunopathogenesis and highlight the potential roles of immune pathway-specific therapeutics.