Transcriptome analysis reveals intrinsic pro-inflammatory signaling in healthy African American skin

High-throughput proteomics identifies inflammatory proteins associated with disease severity and genetic ancestry in patients with hidradenitis suppurativa

BACKGROUND

Hidradenitis suppurativa (HS) is a chronic inflammatory skin condition with a greater prevalence and disease burden in patients who identify as African American and those with a family history of HS, suggesting a strong genetic component to its pathogenesis.

OBJECTIVES

To evaluate the relationship between plasma inflammatory protein expression, HS disease severity and genetic ancestry in a diverse cohort of patients with HS.

METHODS

We performed a case-control, single-centre study of patients with HS and age-, sex- and ethnicity-matched healthy control participants. We profiled circulating inflammatory proteins using Olink® high-throughput proteomics and determined genetic ancestry from whole-genome sequencing data.

RESULTS

Using linear regression, we identified novel proteins associated with HS, after adjusting for age, sex and ethnicity. Our analysis also revealed differences in the inflammatory proteome linked to disease severity. Specifically, we found that plasma levels of interleukin (IL)-6 can distinguish between different Hurley stages, indicating that IL-6 may serve as a marker of disease severity. Additionally, we found variations in inflammatory protein levels based on genetic ancestry: patients with predominantly African ancestry exhibited higher levels of inflammatory proteins associated with neutrophilic inflammation, while those with predominantly European ancestry showed increased levels of T helper 1-related inflammatory proteins.

CONCLUSIONS

Although we were unable to account for treatment status or comorbidities that may influence the level of inflammatory cytokines, genetic ancestry and disease severity may influence the plasma inflammatory profile in patients with HS.

Psoriasis in People With Skin of Color: An Evidence-Based Update

Variations in epidemiology, pathophysiology, genetics, clinical presentation, management, quality of life (QoL) impact, and access to care and research exist globally across the spectrum of individuals with psoriasis. This article aims to provide an evidence-based update on the characteristics of psoriasis in individuals with skin of color (SOC), a population in which psoriasis data have historically been limited. A literature search was conducted from January 2018 until August 2023 in Pubmed/MEDLINE/Cochrane Library and identified studies with I-III level of evidence using Oxford Centre for Evidence-Based Medicine recommendations. Multiple factors (including biological and non-biological) contribute to differences in clinical features and therapeutic nuances in patient populations with SOC. The prevalence of plaque psoriasis is lower in people with SOC but tends to be more severe. People with SOC are less likely to receive biologic treatment. Although the QoL impact of psoriasis is worse in populations with SOC than in White populations, more research is needed to elucidate variations in presentation and impact across diverse populations. An important limitation of this study is that ethnicity, race, and SOC have not been defined universally or used consistently in the literature. Available evidence provides limited information on populations with SOC outside North America, which limits generalizability across global populations. Furthering our understanding of psoriasis in individuals with SOC is crucial to improving patient care outcomes for diverse patient populations worldwide.

Genomic characterization of chronic lymphocytic leukemia in patients of African ancestry

Despite the considerable effort to characterize the genomic landscape of chronic lymphocytic leukemia (CLL), published data have been almost exclusively derived from patients of European Ancestry (EA), with significant underrepresentation of minorities, including patients of African Ancestry (AA). To begin to address this gap, we evaluated whether differences exist in the genetic and transcriptomic features of 157 AA and 440 EA individuals diagnosed with CLL. We sequenced 59 putative driver genes and found an increased frequency of high-impact mutations in AA CLL, including genes of the DNA damage repair (DDR) pathway. Telomere erosion was also increased in AA CLL, amplifying the notion of increased genomic instability in AA CLL. Furthermore, we found transcription enrichment of the Tumor Necrosis Factor-alpha (TNFα) Signaling via NF-κB pathway in AA CLL compared to EA CLL, suggesting that tumor promoting inflammation plays an important role in AA CLL. In summary, these results suggest that genomic instability and NF-kB activation is more prevalent in AA CLL than EA CLL.

IL-1 signaling enrichment in inflammatory skin disease loci with higher-risk allele frequencies in African ancestry

Inflammatory skin diseases (ISDs) exhibit varying prevalence across different ancestry background and geographical regions. Genetic research for complex ISDs has predominantly centered on European Ancestry (EurA) populations and genetic effects on immune cell responses but generally failed to consider contributions from other cell types in skin. Here, we utilized 273 genetic signals from seven different ISDs: acne, alopecia areata (AA), atopic dermatitis (AD), psoriasis, systemic lupus erythematosus (SLE), systemic sclerosis (SSc), and vitiligo, to demonstrate enriched IL1 signaling in keratinocytes, particularly in signals with higher risk allele frequencies in the African ancestry. Using a combination of ATAC-seq, Bru-seq, and promoter capture Hi-C, we revealed potential regulatory mechanisms of the acne locus on chromosome 2q13. We further demonstrated differential responses in keratinocytes upon IL1β stimulation, including the pro-inflammatory mediators CCL5, IL36G, and CXCL8. Taken together, our findings highlight IL1 signaling in epidermal keratinocytes as a contributor to ancestry-related differences in ISDs.

Oral Tranexamic Acid for Prevention and Treatment of Postinflammatory Hyperpigmentation

BACKGROUND

Postinflammatory hyperpigmentation (PIH) is a skin disorder characterized by hyperpigmentation resulting from heightened inflammation and/or damage to the basement membrane, melanocytes, and keratinocytes, leading to abnormal and excessive pigment deposition. Oral tranexamic acid (TXA), originally used as an antifibrinolytic for managing excessive bleeding, has garnered attention for its demonstrated safety and efficacy in treating melasma. There is a growing body of evidence regarding the use of TXA in the treatment of PIH.

OBJECTIVE

To review the mechanism of action of oral TXA in treating PIH and examine the use of oral TXA in preventing and/or treating PIH associated with laser-based and light-based treatments in individuals with skin color.

METHODS

Review of relevant articles from 2000 to present found in the Cochrane Library, PubMed, Embase, and Google Scholar, regarding the use of oral TXA in the treatment of PIH.

RESULTS

Studies reviewed investigated the efficacy of oral tranexamic acid (TXA) in treating postinflammatory hyperpigmentation (PIH) and use in preventing PIH when used in conjunction with other treatments. All studies demonstrated significant improvement in PIH without significant adverse effects and side effects.

CONCLUSION

Oral tranexamic acid is emerging as a safe and effective treatment in the prevention and treatment of postinflammatory hyperpigmentation.

Activation of IL1A/IRAK1 axis and downstream proinflammatory signaling in healthy adult and neonatal African American skin

Differences in prevalence of inflammatory skin diseases including atopic dermatitis and psoriasis in African American (AA) versus White Non-Hispanic (WNH) population are well recognized. However, the underlying mechanisms are largely unknown. We previously observed significant differences in healthy AA skin transcriptome with differentially expressed genes (DEG) enriched for inflammation and cornification processes. Here we analyzed proteome in skin biopsies from healthy AA and WNH volunteers using Olink ® Explore Inflammation 384 biomarker panel. Among proteins with higher expression in AA skin were IRAK1, IL1A, IL4, IL22RA1. IL1A binding to IL1R1 receptor is known to result in recruitment of adapter molecules such as IRAK1, and activation of downstream NF-κB and MAPK signaling. We confirmed NF-κB and ERK1/2 activation in AA skin by Western blot analysis of their phosphorylation at specific activating sites. Importantly, we observed similar differences between AA and WNH neonatal foreskin and between AA and WNH 3D skin organoids. Further analysis of DEG promoters by Gene Transcription Regulation Database (GTRD) pointed to NF-κB and AP1 as key transcription factors involved in AA DEG regulation. Overall, proinflammatory signaling in healthy AA skin starting early in childhood may contribute to the increased risk of certain inflammatory skin diseases within the AA population.

A Descriptive, Post Hoc Analysis of Efficacy and Safety of Risankizumab in Diverse Racial and Ethnic Patient Populations With Moderate-to-Severe Psoriasis

INTRODUCTION

Historically, patients with skin of color are underdiagnosed with psoriasis and underrepresented in clinical trials. In this study, we assess the efficacy and safety of risankizumab in patients with moderate-to-severe plaque psoriasis by race and ethnicity in the open label extension LIMMitless (NCT03047395).

METHODS

Patients received continuous treatment with 150 mg risankizumab through their initial trial and the open label extension. Patients self-identified their race and ethnicity. Efficacy was assessed using Psoriasis Area Severity Index (PASI) and Dermatology Life Quality Index (DLQI). Safety is reported by events/100 patient-years.

RESULTS

A total of 897 patients (race: 662 White, 196 Asian, 25 Black or African American, 14 Other; ethnicity: 98 Hispanic or Latino, 799 non-Hispanic or Latino) were included in this analysis. Compared to baseline, patients had a mean percent reduction in PASI between 94.6% (Asian) and 99.3% (Black or African American) and reported mean percent improvements in DLQI ranging from 87.1% (Asian and Black or African American) to 93.7% (Hispanic or Latino) at week 100.

CONCLUSION

While the data presented here comprise a small retrospective descriptive analysis and cannot detect statistical differences, efficacy of risankizumab for the treatment of moderate-to-severe plaque psoriasis appears similar across the racial and ethnic groups studied and no new safety signals were detected.

Evaluating skin colour diversity in the validation of scar assessment tools

Across scar studies, there is a lack of dark-skinned individuals, who have a predisposition for keloid formation, altered pigmentation and poorer quality of life (QOL). There is a need for patients of colour to be included in scar scale development and validation. In this study, we evaluate the racial diversity of patients included in the validation of scar assessment scales. A systematic review was conducted for articles reporting on the validation of a scar assessment tool. Racial, ethnic and Fitzpatrick skin type (FST) data were extracted. Fifteen scar scale validation studies were included. Nine of the studies did not mention FST, race or ethnicity of the patients. Two of the studies that reported FST or race information only included White patients or included no FST V/VI patients: mapping assessment of scars (MAPS) and University of North Carolina '4P'. Only four studies included non-White patients or dark-skinned patients in the validation of their scar scale: the modified Vancouver Scar Scale (VSS), modified Patient and Observer Scar Assessment Scale (POSAS), acne QOL and SCAR-Q scales. The patients included in the modified VSS validation were 7% and 13% FST V/VI, 14% African in the modified POSAS and 4.5% FST V/VI in the SCAR-Q. We highlight the severe lack of diversity in scar scale validation, with only 4 out of 15 studies including dark-skinned patients. Given the susceptibility of darker-skinned individuals to have poorer scarring outcomes, it is critical to include patients of colour in the very assessment tools that determine their scar prognosis. Inclusion of patients of colour in scar scale development will improve scar assessment and clinical decision-making.

Predictors of female age, health and attractiveness perception from skin feature analysis of digital portraits in five ethnic groups

OBJECTIVE

Research indicates the impact of skin colour, tone evenness and surface topography on ratings of age, health and attractiveness in women. In addition to subjective assessments, these effects have been quantified with objective measures derived from skin image analysis. Signs of skin ageing may manifest differently across ethnic groups. However, comparisons have been limited to research with two ethnic groups, preventing conclusions about an ethnicity-specific ranking of skin ageing signs.

METHODS

We report results from a multi-ethnic and multi-centre study in which faces of women (n = 180; aged 20-69 years) from five ethnic groups were imaged. Facial images were rated for age, health and attractiveness by members of the same ethnic group (each n = 120). Digital image analysis was used to quantify skin colour, gloss, tone evenness and wrinkling/sagging. We assessed associations between face ratings and skin image measurements in the total sample (i.e. all ethnic groups) and separately by ethnicity.

RESULTS

Skin image analysis revealed differences between ethnic groups, including skin colour, gloss, tone evenness, wrinkling and sagging. Differences in the relative predictive utility of individual skin features in accounting for ratings of age, health and attractiveness also were observed between ethnic groups. Facial wrinkling and sagging were the best predictors of face ratings in each ethnic group, with some differences in the type (or predictive magnitude) of skin features.

CONCLUSION

The current findings corroborate previous reports of differences between ethnic groups in female facial skin and indicate differential effects of skin features on ratings of age, health and attractiveness, within and between ethnic groups. Facial wrinkling and sagging were the best predictors of age and attractiveness ratings, and skin tone evenness and gloss had an additional role in ratings of health.

Post-Inflammatory Hyperpigmentation in Dark Skin: Molecular Mechanism and Skincare Implications

Human skin is characterized by significant diversity in color and tone, which are determined by the quantity and distribution of melanin pigment in the epidermis. Melanin absorbs and reflects ultraviolet radiation (UVR), preventing the damage to genomic DNA in the epidermis and degradation of collagen in the dermis; therefore, darker skin types are thought to be well protected from the photodamage because of the high melanin content. However, increased content of melanin in combination with the extrinsic stress factors causing inflammation such as excess UVR, allergic reactions, or injury can also frequently lead to cosmetic problems resulting in discoloration and scarring. This review summarizes current knowledge on histopathology and likely molecular signatures of one of the most common problems, post-inflammatory hyperpigmentation (PIH). The mechanisms proposed so far are subsequently discussed in the context of other factors characterizing darker skin types. This includes the common cellular features, organization of upper skin layers, and major biomarkers, with particular emphasis on increased propensities to systemic and localized inflammation. Enhanced or prolonged inflammatory responses can not only affect the process of melanogenesis but also have been implicated in injury-related skin pathologies and aging. Finally, we summarize the major cosmetic treatments for PIH and their known anti-inflammatory targets, which can be beneficial for darker skin tones and combined with broad-spectrum filters against UVR.

Recent advances in hidradenitis suppurativa: Role of race, genetics, and immunology

Hidradenitis suppurativa (HS) is a multifactorial chronic skin disease characterized by inflammation around the hair follicles commonly affecting intertriginous areas. The underlying pathogenesis of HS and its molecular mechanisms are largely understudied. Genetic studies in families have identified variants within the γ-secretase complex associated with HS; however, no definitive genotype-phenotype correlations have been made. The lack of knowledge regarding the intersection of genetics, immunology and environmental risk factors is a major obstacle to improving treatment for patients with HS. This article provides an overview of the role of race, genetics, and immunology in HS to provide insight into the multiple factors influencing the pathophysiology of HS.

Roles Played by Stress-Induced Pathways in Driving Ethnic Heterogeneity for Inflammatory Skin Diseases

Immune-mediated skin conditions (IMSCs) are a diverse group of autoimmune diseases associated with significant disease burden. Atopic dermatitis and psoriasis are among the most common IMSCs in the United States and have disproportionate impact on racial and ethnic minorities. African American patients are more likely to develop atopic dermatitis compared to their European American counterparts; and despite lower prevalence of psoriasis among this group, African American patients can suffer from more extensive disease involvement, significant post-inflammatory changes, and a decreased quality of life. While recent studies have been focused on understanding the heterogeneity underlying disease mechanisms and genetic factors at play, little emphasis has been put on the effect of psychosocial or psychological stress on immune pathways, and how these factors contribute to differences in clinical severity, prevalence, and treatment response across ethnic groups. In this review, we explore the heterogeneity of atopic dermatitis and psoriasis between African American and European American patients by summarizing epidemiological studies, addressing potential molecular and environmental factors, with a focus on the intersection between stress and inflammatory pathways.