Systemic sclerosis

Silica's silent threat: Contributing to skin fibrosis in systemic sclerosis by targeting the HDAC4/Smad2/3 pathway

Nowadays, silica products are widely used in daily life, especially in skin applications, which inevitably increases the risk of silica exposure in general population. However, inadequate awareness of silica's potential hazards and lack of self-protection are of concern. Systemic sclerosis (SSc) is characterized by progressive tissue fibrosis under environmental and genetic interactions. Silica exposure is considered an important causative factor for SSc, but its pathogenesis remains unclear. Within this study, we showed that lower doses of silica significantly promoted the proliferation, migration, and activation of human skin fibroblasts (HSFs) within 24 h. Silica injected subcutaneously into mice induced and exacerbated skin fibrosis. Notably, silica increased histone deacetylase-4 (HDAC4) expression by inducing its DNA hypomethylation in normal HSFs. The elevated HDAC4 expression was also confirmed in SSc HSFs. Furthermore, HDAC4 was positively correlated with Smad2/3 phosphorylation and COL1, α-SMA, and CTGF expression. The HDAC4 inhibitor LMK235 mitigated silica-induced upregulation of these factors and alleviated skin fibrosis in SSc mice. Taken together, silica induces and exacerbates skin fibrosis in SSc patients by targeting the HDAC4/Smad2/3 pathway. Our findings provide new insights for evaluating the health hazards of silica exposure and identify HDAC4 as a potential interventional target for silica-induced SSc skin fibrosis.

A study of the reliability and construct validity of the 1-minute sit-to-stand test for individuals with systemic sclerosis

OBJECTIVE

This study seeks to assess the reliability and construct validity of the 1-minute sit-to-stand test as an efficient tool for evaluating the functional capacity of individuals with systemic sclerosis, considering its time and space effectiveness.

METHODS

This cross-sectional study recruited forty-nine individuals with systemic sclerosis from a university hospital in Denmark. The 1-minute sit-to-stand test was conducted twice on the same day, with an interval of approximately 10 to 15 minutes between administrations, followed by a single administration of the 6-minute walk test. Reliability and validity were estimated using Bland-Altman statistics, intraclass correlation coefficient (ICC2,1), paired t-test, and Spearman's rank correlation coefficient (ρ).

RESULTS

The 1-minute sit-to-stand test exhibited excellent test-retest reliability with an ICC2,1 (CI) of 0.97 (0.95-0.99). The minimal metrically detectable change between separate measures on a subject for the difference in the measures to be considered real at the 95% confidence level was 2.9 repetitions and 11%, respectively. A learning effect of one repetition was observed between repeated measures. High construct validity was observed between the 1-minute sit-to-stand and 6-minute walk test (ρ = 0.78, p < .001).

CONCLUSIONS

This study demonstrates the 1-minute sit-to-stand test as highly reliable, with an 11% change indicating a true outcome change. It also demonstrates robust construct validity compared to the 6-minute walk test. The 1-minute sit-to-stand test appears feasible for assessing functional capacity in well-functioning individuals with systemic sclerosis, but prior familiarization with the task is recommended, as a small learning effect was observed with one repetition.

Bilateral Optic Neuropathy in Association with Diffuse Cutaneous Systemic Sclerosis with Interstitial Lung Disease

PURPOSE

To report a rare case of bilateral optic neuropathy in a patient with diffuse cutaneous systemic sclerosis with interstitial lung disease.

METHOD

Retrospective case report.

RESULT

A middle-aged female, who was a known case of systemic sclerosis with interstitial lung disease, was presented with sudden painless bilateral loss of vision for a month. The fundoscopy findings were suggestive of bilateral optic atrophy. Anti-topoisomerase I was found in the serum. Serum B12 and folate levels were reduced. HRCT Chest was suggestive of interstitial lung disease. MRI brain was normal and MRI orbit showed kinking of the left optic nerve. The findings were suggestive of diffuse cutaneous systemic sclerosis with interstitial lung disease and bilateral optic neuropathy.

CONCLUSION

This is a rare case of bilateral optic neuropathy in a patient with diffuse cutaneous systemic sclerosis and interstitial lung disease with profound vision loss, in the absence of renal or cardiac involvement.

Autoimmune diseases and atherosclerotic cardiovascular disease

Autoimmune diseases are associated with a dramatically increased risk of atherosclerotic cardiovascular disease and its clinical manifestations. The increased risk is consistent with the notion that atherogenesis is modulated by both protective and disease-promoting immune mechanisms. Notably, traditional cardiovascular risk factors such as dyslipidaemia and hypertension alone do not explain the increased risk of cardiovascular disease associated with autoimmune diseases. Several mechanisms have been implicated in mediating the autoimmunity-associated cardiovascular risk, either directly or by modulating the effect of other risk factors in a complex interplay. Aberrant leukocyte function and pro-inflammatory cytokines are central to both disease entities, resulting in vascular dysfunction, impaired resolution of inflammation and promotion of chronic inflammation. Similarly, loss of tolerance to self-antigens and the generation of autoantibodies are key features of autoimmunity but are also implicated in the maladaptive inflammatory response during atherosclerotic cardiovascular disease. Therefore, immunomodulatory therapies are potential efficacious interventions to directly reduce the risk of cardiovascular disease, and biomarkers of autoimmune disease activity could be relevant tools to stratify patients with autoimmunity according to their cardiovascular risk. In this Review, we discuss the pathophysiological aspects of the increased cardiovascular risk associated with autoimmunity and highlight the many open questions that need to be answered to develop novel therapies that specifically address this unmet clinical need.

Single-cell analysis in rheumatic and allergic diseases: insights for clinical practice

Since the advent of single-cell RNA sequencing (scRNA-seq) methodology, single-cell analysis has become a powerful tool for exploration of cellular networks and dysregulated immune responses in disease pathogenesis. Advanced bioinformatics tools have enabled the combined analysis of scRNA-seq data and information on various cell properties, such as cell surface molecular profiles, chromatin accessibility and spatial information, leading to a deeper understanding of pathology. This Review provides an overview of the achievements in single-cell analysis applied to clinical samples of rheumatic and allergic diseases, including rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, allergic airway diseases and atopic dermatitis, with an expanded scope beyond peripheral blood cells to include local diseased tissues. Despite the valuable insights that single-cell analysis has provided into disease pathogenesis, challenges remain in translating single-cell findings into clinical practice and developing personalized treatment strategies. Beyond understanding the atlas of cellular diversity, we discuss the application of data obtained in each study to clinical practice, with a focus on identifying biomarkers and therapeutic targets.

Protocol for the development of a tool to map systemic sclerosis pain sources, patterns, and management experiences: a Scleroderma Patient-centered Intervention Network patient-researcher partnership

INTRODUCTION

Systemic sclerosis (SSc) is a rare, complex autoimmune rheumatic disease with multiple factors that contribute to pain. People with SSc emphasize the effect pain has on their quality of life, but no studies have systematically examined the frequency and relative importance of different SSc pain sources, patterns of pain from different sources, and pain management experiences. Our objectives are to (1) develop a tool, jointly with researchers, health care providers, and patients, to map sources of pain in SSc, determine patterns of pain from different sources, and understand pain management experiences; and (2) administer the final tool version to participants in the large multinational Scleroderma Patient-centered Intervention Network (SPIN) Cohort.

METHODS

First, we will use validated pain assessment tools as templates to develop an initial version of our pain assessment tool, and we will obtain input from patient advisors to adapt it for SSc. The tool will include questions on pain sources, pain patterns, pain intensity, pain management techniques, and barriers to pain management in SSc. Second, we will conduct nominal group technique sessions with people living with SSc and health care providers who care for people with SSc to further refine the tool. Third, we will conduct individual usability testing sessions with SPIN Cohort participants. Once the tool has been finalized, we will administer it to individuals in the multinational SPIN Cohort, which currently includes over 1,300 active participants from 54 sites in 7 countries. We will perform unsupervised clustering using the KAy-Means for MIxed LArge data (KAMILA) method to identify participant subgroups with similar profiles of pain sources (present or absent) and to evaluate predictors of subgroup membership. We will use latent profile analysis to identify subgroups of participants with similar profiles based on pain intensity scores for each pain source and evaluate predictors.

DISCUSSION

Once completed, our pain assessment tool will allow our team and other researchers to map sources of pain in SSc and to understand pain management experiences of people living with SSc. This knowledge will provide avenues for studies on the pathophysiology of pain in SSc and studies of interventions to improve pain management.

Virus-Induced MicroRNA Modulation and Systemic Sclerosis Disease

MicroRNAs (miRNAs) are short noncoding RNA sequences that regulate gene expression at the post-transcriptional level. They are involved in the regulation of multiple pathways, related to both physiological and pathological conditions, including autoimmune diseases, such as Systemic Sclerosis (SSc). Specifically, SSc is recognized as a complex and multifactorial disease, characterized by vascular abnormalities, immune dysfunction, and progressive fibrosis, affecting skin and internal organs. Among predisposing environmental triggers, evidence supports the roles of oxidative stress, chemical agents, and viral infections, mostly related to those sustained by beta-herpesviruses such as HCMV and HHV-6. Dysregulated levels of miRNA expression have been found in SSc patients compared to healthy controls, at both the intra- and extracellular levels, providing a sort of miRNA signature of the SSc disease. Notably, HCMV/HHV-6 viral infections were shown to modulate the miRNA profile, often superposing that observed in SSc, potentially promoting pathological pathways associated with SSc development. This review summarizes the main data regarding miRNA alterations in SSc disease, highlighting their potential as prognostic or diagnostic markers for SSc disease, and the impact of the putative SSc etiological agents on miRNA modulation.

HLA Association among Thai Patients with Diffuse and Limited Cutaneous Systemic Sclerosis

This study aimed to clarify the association of HLA Class I and II with dcSSc and lcSSc in Thais. HLA typing for 11 gene loci (Class I: HLA-A, B and C, and Class II [HLA-DR, DP and DQ]) was carried out using the Next Generation DNA Sequencing method (three fields) in 92 Thai patients with systemic sclerosis (55 dcSSc, 37 lcSSc) and 135 healthy controls (HCs). The distribution of HLA alleles in patients with dcSSc and lcSSc was compared. When compared with HCs, the AF of A*24:02:01, A*24:07:01, B*27:04:01 and B*27:06 showed an increasing trend in lcSSc patients without statistical significance. DRB1*15:02:01, DRB5*01:02:01, DQA1*01:01:01, DQB1*05:01:24, DPA1*02:01:01 and DPB1*13:01:01 increased significantly in dcSSc patients. DQB1*05:01:24 and DPB1*13:01:01 also increased significantly in lcSSc patients, but less significantly than in dcSSc patients. The association of DPB1*05:01:01 with lcSSc was significantly protective. HLA-A*24:02:01, B*27:06 and C*03:04:01 formed a three-locus haplotype that also constituted an eight-locus haplotype with DRB1*15:02:01, DQA1*01:01:01, DQB1*05:01:24, DPA1*02:01:01 and DPB1*13:01:01. There was a possibility that HLA Class I would play a role in the pathogenesis of lcSSc, while Class II played more of a role in the dcSSc in Thai patients.

Low-Carbon Monoxide Diffusing Capacity, Patient-Reported Measures and Reduced Nailfold Capillary Density Are Associated with Interstitial Lung Disease in Systemic Sclerosis

The aim of this paper is to identify factors associated with interstitial lung disease (ILD) in patients with systemic sclerosis (SSc) and build an algorithm to better define this association for a personalised application in clinical practice.

METHODS

A total of 78 SSc patients underwent HRCT to assess ILD. Demographic, clinical and laboratory variables were collected, focusing on those associated either directly or indirectly with lung involvement. The discriminant value of each variable was determined using the operating characteristic curves (ROC) and included in a model to estimate the strength of ILD association in SSc.

RESULTS

Thirty-three (42.31%) patients showed ILD on HRCT. DLco, M-Borg, GERD-Q and capillary density were significantly associated with the presence of ILD-SSc. A model including these variables had a coefficient of determination (R2) of 0.697. DLco had an AUC of 0.861 (p < 0.001) with a cut-off of ≤72.3% (sensitivity 78.8%, specificity 91.1%, +LR 8.86). The m-Borg Scale showed an AUC of 0.883 (p < 0.001) with a cut-off >2 (sensitivity 84.8%, specificity 82.2%, +LR 4.77), GERD-Q had an AUC of 0.815 (p < 0.001) with a cut-off >7 (sensitivity 72.7%, specificity 86.7%, +LR 5.45). The capillary density showed an AUC of 0.815 (p < 0.001) with a cut-off of ≤4.78 (sensitivity 87.9%, specificity 68.9%, +LR 2.82). Based on the pre-test probability values, these four variables were applied to Fagan's nomogram to calculate the post-test probability of this association.

CONCLUSIONS

Our study identified four associated clinical factors of ILD in SSc patients. Moreover, their inclusion in an algorithm for the post-test probability, tailored to the specific patients' characteristics, significantly increases the ability to find out the presence of SSc-ILD.

Scleroderma and scleroderma-like syndromes

Systemic sclerosis is a systemic connective tissue disease whose main pathophysiological mechanism is a progressive fibrosis of internal organs and skin leading to thickening and induration. Blood vessels may also be involved. However, systemic scleroderma is not the only disease causing cutaneous sclerosis. There is a group of diseases that mimic scleroderma in their clinical presentation - these are scleroderma-like syndromes. A distinction can be made between syndromes of inflammatory/autoimmune, genetic, metabolic, toxic, drug-induced, occupational, paraneoplastic and syndromes caused by deposition disorders. In the following paper, we have reviewed the literature on scleroderma-like syndromes. We have outlined the factors predisposing to the development of each disease, its pathogenesis, clinical presentation, diagnostic and treatment process and the differences between each syndrome and systemic scleroderma.

Delivery technologies for therapeutic targeting of fibronectin in autoimmunity and fibrosis applications

Fibronectin (FN) is a critical component of the extracellular matrix (ECM) contributing to various physiological processes, including tissue repair and immune response regulation. FN regulates various cellular functions such as adhesion, proliferation, migration, differentiation, and cytokine release. Alterations in FN expression, deposition, and molecular structure can profoundly impact its interaction with other ECM proteins, growth factors, cells, and associated signaling pathways, thus influencing the progress of diseases such as fibrosis and autoimmune disorders. Therefore, developing therapeutics that directly target FN or its interaction with cells and other ECM components can be an intriguing approach to address autoimmune and fibrosis pathogenesis.

The potential pathogenic role of gut microbiota in rheumatic diseases: a human-centred narrative review

A growing amount of evidence suggests that gut microbiota plays an important role in human health, including a possible role in the pathogenesis of rheumatic and musculoskeletal diseases (RMD). We analysed the current evidence about the role of microbiota in rheumatoid arthritis (RA), spondyloarthritis (SpA), systemic lupus erythematosus (SLE) and systemic sclerosis (SSc). In RA, we found a general consensus regarding a reduction of diversity and a specific bacterial signature, with consistent changes according to the different ethnic and geographical areas. The major pathogenetic role in RA is recognised for P. copri, L. salivarius and Collinsella, even if findings become more heterogeneous when considering established disease. In SpA, we found a relative gut abundance of Akkermansia, Coprococcus, Ruminoccocus and a relative reduction in Bacterioides and Firmicutes spp. Human and preclinical data suggest loss of mucosal barrier, increased permeability and Th1- and Th17-mediated inflammation. Additionally, HLA-B27 seems to play a role in shaping the intestinal microbiota and the consequent inflammation. In SLE, the typical gut microbiota signature was characterised by a reduction in the Firmicutes/Bacteroidetes ratio and by enrichment of Rhodococcus, Eggerthella, Klebsiella, Prevotella, Eubacterium and Flavonifractor, even if their real pathogenic impact remains unclear. In SSc, gastrointestinal dysbiosis is well documented with an increase of pro-inflammatory species (Fusobacterium, Prevotella, Ruminococcus, Akkermansia, γ-Proteobacteria, Erwinia, Trabsulsiella, Bifidobacterium, Lactobacillus, Firmicutes and Actinobacteria) and a reduction of species as Faecalibacterium, Clostridium, Bacteroidetes and Rikenella. In conclusion, seems possible to recognise a distinct gut microbiota profile for each RMD, even if significant differences in bacterial species do exist between different studies and there is a high risk of bias due to the cross-sectional nature of such studies. Therefore longitudinal studies are needed, especially on patients with preclinical and early disease, to investigate the real role of gut microbiota in the pathogenesis of RMD.

Contributions of Synthetic Chemicals to Autoimmune Disease Development and Occurrence

PURPOSE OF REVIEW

Exposure to many synthetic chemicals has been linked to a variety of adverse human health effects, including autoimmune diseases. In this scoping review, we summarize recent evidence detailing the effects of synthetic environmental chemicals on autoimmune diseases and highlight current research gaps and recommendations for future studies.

RECENT FINDINGS

We identified 68 recent publications related to environmental chemical exposures and autoimmune diseases. Most studies evaluated exposure to persistent environmental chemicals and autoimmune conditions including rheumatoid arthritis (RA), systemic lupus (SLE), systemic sclerosis (SSc), and ulcerative colitis (UC) and Crohn's disease. Results of recent original research studies were mixed, and available data for some exposure-outcome associations were particularly limited. PFAS and autoimmune inflammatory bowel diseases (UC and CD) and pesticides and RA appeared to be the most frequently studied exposure-outcome associations among recent publications, despite a historical research focus on solvents. Recent studies have provided additional evidence for the associations of exposure to synthetic chemicals with certain autoimmune conditions. However, impacts on other autoimmune outcomes, particularly less prevalent conditions, remain unclear. Owing to the ubiquitous nature of many of these exposures and their potential impacts on autoimmune risk, additional studies are needed to better evaluate these relationships, particularly for understudied autoimmune conditions. Future research should include larger longitudinal studies and studies among more diverse populations to elucidate the temporal relationships between exposure-outcome pairs and to identify potential population subgroups that may be more adversely impacted by immune modulation caused by exposure to these chemicals.

IL-17 Control of Cutaneous Immune Homeostasis

IL-17 is widely recognized for its roles in host defense and inflammatory disorders. However, it has become clear that IL-17 is also an essential regulator of barrier tissue physiology. Steady-state microbe sensing at the skin surface induces low-level IL-17 expression that enhances epithelial integrity and resists pathogens without causing overt inflammation. Recent reports describe novel protective roles for IL-17 in wound healing and counteracting physiologic stress; however, chronic amplification of these beneficial responses contributes to skin pathologies as diverse as fibrosis, cancer, and autoinflammation. In this paper, we discuss the context-specific roles of IL-17 in skin health and disease and therapeutic opportunities.

Impaired LAIR-1-mediated immune control due to collagen degradation in fibrosis

Tissue repair is disturbed in fibrotic diseases like systemic sclerosis (SSc), where the deposition of large amounts of extracellular matrix components such as collagen interferes with organ function. LAIR-1 is an inhibitory collagen receptor highly expressed on tissue immune cells. We questioned whether in SSc, impaired LAIR-1-collagen interaction is contributing to the ongoing inflammation and fibrosis. We found that SSc patients do not have an intrinsic defect in LAIR-1 expression or function. Instead, fibroblasts from healthy controls and SSc patients stimulated by soluble factors that drive inflammation and fibrosis in SSc deposit disorganized collagen products in vitro, which are dysfunctional LAIR-1 ligands. This is dependent of matrix metalloproteinases and platelet-derived growth factor receptor signaling. In support of a non-redundant role of LAIR-1 in the control of fibrosis, we found that LAIR-1-deficient mice have increased skin fibrosis in response to repeated injury and in the bleomycin mouse model for SSc. Thus, LAIR-1 represents an essential control mechanism for tissue repair. In fibrotic disease, excessive collagen degradation may lead to a disturbed feedback loop. The presence of functional LAIR-1 in patients provides a therapeutic opportunity to reactivate this intrinsic negative feedback mechanism in fibrotic diseases.

Reliability, validity, and sensitivity of the Japanese version of the University of California Los Angeles scleroderma clinical trial consortium gastrointestinal tract instrument: Application to efficacy assessment of intravenous immunoglobulin administration

This study aimed to develop and assess the reliability, validity, and sensitivity of the Japanese version of the University of California Los Angeles Scleroderma Clinical Trial Consortium gastrointestinal tract (GIT) Instrument 2.0 (the GIT score), as an evaluation tool for GIT symptoms in systemic sclerosis (SSc). The Japanese version of the GIT score was constructed using the forward-backward method. The reliability and validity of this instrument were evaluated in a cohort of 38 SSc patients. Correlation analysis was conducted to assess the relationship between the GIT score and existing patient-reported outcome measures. Additionally, the sensitivity of the GIT score was examined by comparing GIT scores before and after intravenous immunoglobulin (IVIG) administration in 10 SSc-myositis overlap patients, as IVIG has recently demonstrated effectiveness in alleviating GIT symptoms of SSc. As a result, the Japanese version of the GIT score exhibited internal consistency and a significant association with the Frequency Scale for the Symptoms of Gastroesophageal Reflux Disease. Furthermore, the total GIT score, as well as the reflux and distention/bloating subscales, displayed moderate correlations with the EuroQol 5 dimensions (EQ-5D) pain/discomfort subscale and the Short Form-36 body pain subscale. Notably, following IVIG treatment, there was a statistically significant reduction in the total GIT score and multiple subscales. We first validated the Japanese version of the GIT score in Japanese SSc patients in real-world clinical settings. This instrument holds promise for application in future clinical trials involving this patient population.

Assessing hand and global disability in a cohort of Algerian patients with systemic sclerosis: Construct validities of the Arab Hand Function Index and the Arabic Health Assessment Questionnaire

Objective

The study aimed to assess the construct validity of the Arab Hand Function Index and the Arabic Health Assessment Questionnaire in Algerian patients with systemic sclerosis.

Methods

Consecutive Algerian patients who fulfilled the American College of Rheumatology/European League Against Rheumatism criteria for systemic sclerosis were included. In addition to disease characteristics, global disability and hand disability were assessed using the Arabic Health Assessment Questionnaire and the Arab Hand Function Index, respectively. Construct validity was assessed by convergent and divergent validity (Spearman's rank correlation coefficient) and factor analysis. The scale reliability was assessed using the Cronbach's alpha.

Results

We evaluated 100 systemic sclerosis patients (83 females) of mean ± standard deviation age 46.7 ± 12.3 years, including 59 limited cutaneous systemic sclerosis and 41 diffuse cutaneous systemic sclerosis. Raynaud's phenomenon was detected in 99 patients and digital ulcers in 25. Gastrointestinal tract involvement and interstitial lung disease were detected in 86/100 (86%) and 46/72 (63.9%) patients, respectively. Anti-topoisomerase I and anti-centromere antibodies were detected in 33/76 (43.4%) and 23/76 (30.3%) patients, respectively. The Arab Hand Function Index had a good construct validity with a total score explaining 61% of the variance of the Arabic Health Assessment Questionnaire which also had a good construct validity. Factor analysis of the Arab Hand Function Index and the Arabic Health Assessment Questionnaire items extracted two factors explaining 64% of the variance for the Arab Hand Function Index and one factor explaining 55% of the variance for the Arabic Health Assessment Questionnaire. The Arab Hand Function Index and the Arabic Health Assessment Questionnaire were reliable questionnaires with a Cronbach's alpha >0.8.

Conclusion

In Algerian patients with systemic sclerosis, Arab Hand Function Index and Arabic Health Assessment Questionnaire have a good construct validity and reliability.

Pulmonary function in Thai patients with systemic sclerosis; a single center 6-year retrospective study

Background

Pulmonary involvement is a major cause of internal organ complication and the leading cause of death in patients with systemic sclerosis (SSc). This study aimed to demonstrate the characteristics of pulmonary function (PF) in Thai patients with SSc and the association between PF and body mass index (BMI) and anti-topoisomerase (anti-Scl70).

Methods

All patients diagnosed with SSc in our tertiary care teaching hospital database between 2016 and 2021 were reviewed and analyzed.

Results

Of 211 SSc patients, 128 patients who underwent the PF test were enrolled; 102 (79.7%) were female. The mean age was 54 years. The median BMI for all patients was 21.7 kg/m 2. Regarding anti-Scl70, 10.9% of patients were positive, 7.8% were negative, and the status was unreported for 81.3%. The mean (SD) forced expiratory volume in one second (FEV1) forced vital capacity (FVC) ratio was 0.8 (0.1). The mean (SD) % predicted values of FEV1, FVC, and diffusing capacity of the lungs for carbon monoxide (DLCO) were 76.3 (16.3), 69.1 (15.8), and 75.5 (22.8), respectively. A restrictive spirometry pattern (RSP) was found in 78.8% of the patients. DLCO had a moderate positive linear correlation with FVC (r=0.50, p <0.001) and a moderate negative linear correlation with BMI (r=-0.36, p <0.001). However, there was no correlation between FVC and BMI. There was no statistical difference in demographic data or the presence of anti-Scl70 among patients with or without RSP.

Conclusions

RSP is common among Thai patients with SSc. However, the power of using demographic data and the presence of anti-Scl70 to determine the probability of pulmonary involvement remains limited.

Dysregulation of circulating collagen turnover markers in very early systemic sclerosis

OBJECTIVE

Clinical observation suggests that vascular activation and autoimmunity precede remodelling of the extracellular matrix (ECM) in systemic sclerosis (SSc). We challenge this paradigm by hypothesising that ECM biomarkers are already disturbed in patients with very early SSc (veSSc) when fibrosis is not yet clinically detectable.

METHODS

42 patients with veSSc, defined as the presence of Raynaud's phenomenon and at least one of puffy fingers, positive antinuclear antibodies or pathological nailfold capillaroscopy, not meeting the 2013 American College of Rheumatology/European Alliance of Associations for Rheumatology classification criteria for SSc, were compared with healthy controls (HCs, n=29). ECM degradation (BGM, C3M, C4M and C6M) and ECM formation biomarkers (PRO-C3, PRO-C4 and PRO-C5) were measured in serum using ELISAs. A cross-sectional analysis at baseline and a longitudinal analysis was performed.

RESULTS

Compared with HC, veSSc patients showed a strongly dysregulated turnover of type III and IV collagens (higher C3M, C4M, both p<0.0001 and PRO-C3, p=0.004, lower turnover ratios PRO-C3/C3M and PRO-C4/C4M, both p<0.0001). The biglycan degradation biomarker BGM was higher in veSSc than in HC (p=0.006), whereas the degradation biomarker for type VI collagen, C6M, was lower (p=0.002). In an ROC analysis, biomarkers of type III and IV collagen excellently distinguished between veSSc and HC: C3M, AUC=0.95, p<0.0001; C4M, AUC=0.97, p<0.0001; turnover ratios PRO-C3/C3M, AUC=0.80, p<0.0001; PRO-C4/C4M, AUC=0.97; p<0.0001.

CONCLUSION

These findings indicate ECM remodelling as a very early phenomenon of SSc occurring in parallel with microvascular and autoimmune changes. Biomarkers of type III and IV collagens distinguished between veSSc patients and HC, indicating them as potential biomarkers for the detection of veSSc.

The association between the neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and monocyte-to-lymphocyte ratio and systemic sclerosis and its complications: a systematic review and meta-analysis

Introduction

The identification of new, easily measurable biomarkers might assist clinicians in diagnosing and managing systemic sclerosis (SSc). Although the full blood count is routinely assessed in the evaluation of SSc, the diagnostic utility of specific cell-derived inflammatory indices, i.e., neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and monocyte-to-lymphocyte ratio (MLR), has not been critically appraised in this patient group.

Methods

We conducted a systematic review and meta-analysis of studies investigating the NLR, PLR, and MLR, in SSc patients and healthy controls and in SSc patients with and without relevant complications. PubMed, Scopus, and Web of Science were searched from inception to 23 February 2024. Risk of bias and certainty of evidence were assessed using validated tools.

Results

In 10 eligible studies, compared to controls, patients with SSc had significantly higher NLR (standard mean difference, SMD=0.68, 95% CI 0.46 to 0.91, p<0.001; I2 = 74.5%, p<0.001), and PLR values (SMD=0.52, 95% CI 0.21 to 0.83, p=0.001; I2 = 77.0%, p=0.005), and a trend towards higher MLR values (SMD=0.60, 95% CI -0.04 to 1.23, p=0.066; I2 = 94.1%, p<0.001). When compared to SSc patients without complications, the NLR was significantly higher in SSc with interstitial lung disease (ILD, SMD=0.31, 95% CI 0.15 to 0.46, p<0.001; I2 = 43.9%, p=0.11), pulmonary arterial hypertension (PAH, SMD=1.59, 95% CI 0.04 to 3.1, p=0.045; I2 = 87.6%, p<0.001), and digital ulcers (DU, SMD=0.43, 95% CI 0.13 to 0.74, p=0.006; I2 = 0.0%, p=0.49). The PLR was significantly higher in SSc patients with ILD (SMD=0.42, 95% CI 0.25 to 0.59, p<0.001; I2 = 24.8%, p=0.26). The MLR was significantly higher in SSc patients with PAH (SMD=0.63, 95% CI 0.17 to 1.08, p=0.007; I2 = 66.0%, p=0.086), and there was a trend towards a higher MLR in SSc patients with ILD (SMD=0.60, 95% CI -0.04 to 1.23, p=0.066; I2 = 94.1%, p<0.001).

Discussion

Pending the results of appropriately designed prospective studies, the results of this systematic review and meta-analysis suggest that blood cell-derived indices of inflammation, particularly the NLR and PLR, may be useful in the diagnosis of SSc and specific complications.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42024520040.

Immunogenetics of Systemic Sclerosis

Systemic sclerosis (SSc) is a rare autoimmune connective tissue disorder characterized by massive fibrosis, vascular damage, and immune imbalance. Advances in rheumatology and immunology over the past two decades have led to a redefinition of systemic sclerosis, shifting from its initial perception as primarily a "hyperfibrotic" state towards a recognition of systemic sclerosis as an immune-mediated disease. Consequently, the search for genetic markers has transitioned from focusing on fibrotic mechanisms to exploring immune regulatory pathways. Immunogenetics, an emerging field at the intersection of immunology, molecular biology, and genetics has provided valuable insights into inherited factors that influence immunity. Data from genetic studies conducted thus far indicate that alterations in genetic messages can significantly impact disease risk and progression. While certain genetic variations may confer protective effects, others may exacerbate disease susceptibility. This paper presents a comprehensive review of the most relevant genetic changes that influence both the risk and course of systemic sclerosis. Special emphasis is placed on factors regulating the immune response, recognizing their pivotal role in the pathogenesis of the disease.

Anti-CX3CL1 (fractalkine) monoclonal antibody attenuates lung and skin fibrosis in sclerodermatous graft-versus-host disease mouse model

BACKGROUND

Systemic sclerosis (SSc) is an autoimmune disease characterized by vascular injury and inflammation, followed by excessive fibrosis of the skin and other internal organs, including the lungs. CX3CL1 (fractalkine), a chemokine expressed on endothelial cells, supports the migration of macrophages and T cells that express its specific receptor CX3CR1 into targeted tissues. We previously reported that anti-CX3CL1 monoclonal antibody (mAb) treatment significantly inhibited transforming growth factor (TGF)-β1-induced expression of type I collagen and fibronectin 1 in human dermal fibroblasts. Additionally, anti-mouse CX3CL1 mAb efficiently suppressed skin inflammation and fibrosis in bleomycin- and growth factor-induced SSc mouse models. However, further studies using different mouse models of the complex immunopathology of SSc are required before the initiation of a clinical trial of CX3CL1 inhibitors for human SSc.

METHODS

To assess the preclinical utility and functional mechanism of anti-CX3CL1 mAb therapy in skin and lung fibrosis, a sclerodermatous chronic graft-versus-host disease (Scl-cGVHD) mouse model was analyzed with immunohistochemical staining for characteristic infiltrating cells and RNA sequencing assays.

RESULTS

On day 42 after bone marrow transplantation, Scl-cGVHD mice showed increased serum CX3CL1 level. Intraperitoneal administration of anti-CX3CL1 mAb inhibited the development of fibrosis in the skin and lungs of Scl-cGVHD model, and did not result in any apparent adverse events. The therapeutic effects were correlated with the number of tissue-infiltrating inflammatory cells and α-smooth muscle actin (α-SMA)-positive myofibroblasts. RNA sequencing analysis of the fibrotic skin demonstrated that cGVHD-dependent induction of gene sets associated with macrophage-related inflammation and fibrosis was significantly downregulated by mAb treatment. In the process of fibrosis, mAb treatment reduced cGVHD-induced infiltration of macrophages and T cells in the skin and lungs, especially those expressing CX3CR1.

CONCLUSIONS

Together with our previous findings in other SSc mouse models, the current results indicated that anti-CX3CL1 mAb therapy could be a rational therapeutic approach for fibrotic disorders, such as human SSc and Scl-cGVHD.

TLR8 aggravates skin inflammation and fibrosis by activating skin fibroblasts in systemic sclerosis

OBJECTIVES

Innate immunity significantly contributes to SSc pathogenesis. TLR8 is an important innate immune mediator that is implicated in autoimmunity and fibrosis. However, the expression, mechanism of action, and pathogenic role of TLR8 in SSc remain unclear. The aim of this study was to explore the roles and underlying mechanisms of TLR8 in SSc.

METHODS

The expression of TLR8 was analysed, based on a public dataset, and then verified in skin tissues and skin fibroblasts of SSc patients. The role of TLR8 in inflammation and fibrosis was investigated using a TLR8-overexpression vector, activator (VTX-2337), inhibitor (cu-cpt-8m), and TLR8 siRNA in skin fibroblasts. The pathogenic role of TLR8 in skin inflammation and fibrosis was further validated in a bleomycin (BLM)-induced mouse skin inflammation and fibrosis model.

RESULTS

TLR8 levels were significantly elevated in SSc skin tissues and myofibroblasts, along with significant activation of the TLR8 pathway. In vitro studies showed that overexpression or activation of TLR8 by a recombinant plasmid or VTX-2337 upregulated IL-6, IL-1β, COL I, COL III and α-SMA in skin fibroblasts. Consistently, both TLR8-siRNA and cu-cpt-8m reversed the phenotypes observed in TLR8-activating fibroblasts. Mechanistically, TLR8 induces skin fibrosis and inflammation in a manner dependent on the MAPK, NF-κB and SMAD2/3 pathways. Subcutaneous injection of cu-cpt-8m significantly alleviated BLM-induced skin inflammation and fibrosis in vivo.

CONCLUSION

TLR8 might be a promising therapeutic target for improving the treatment strategy for skin inflammation and fibrosis in SSc.

Journey into the Esophageal Complications: Decoding Systemic Sclerosis with Cutting-Edge Endoscopy, Manometry, and Ambulatory pH-Study

Purpose

Systemic Sclerosis (SSc) is a rare connective tissue disorder characterized by autoimmunity, fibrosis, and vasculopathy that affects the skin and internal organs, including the gastrointestinal tract, particularly the esophagus. This article highlights the characteristics and clinical symptoms of esophageal involvement in patients with SSc.

Patients and Methods

This study was conducted between November 2022 to August 2023, including 26 already diagnosed cases of SSc in the Department of Rheumatology and Rehabilitation and Kurdistan Center for Gastroenterology and Hepatology-Sulaymaniyah, Iraq. Esophageal involvement was investigated using esophageal manometry, esophagogastroduodenoscopy (EGD), and 24-hour impedance-pH monitoring.

Results

Females were significantly predominant (P = 0.019) regarding the symptoms; 76.9% of the patients had heart burn, 76.9% dysphagia, 73.1% water brush, and 69.2% regurgitation. In total, 69.2% of the patients showed erosive gastrointestinal reflux disease (GERD) on EGD, 76.9% had decreased lower esophageal sphincter pressure (DLESP) and decreased distal esophageal peristaltic contractions (DDEPC) on esophageal manometry, and 84.6% had reflux on pH monitoring. Raynaud's phenomenon is the most common and typically the earliest clinical manifestation of SSc. The presence of erosive GERD was found to significantly increase the risk of developing dysphagia (B = 4.725, P = 0.014, OR = 3.482) and regurgitation (B = 3.521, P = 0.006, OR = 4.030).

Conclusion

It is crucial to take gender-specific considerations into account when diagnosing and managing esophageal complications in patients with systemic sclerosis (SSc). Additionally, employing various diagnostic assessments to detect esophageal involvement during SSc is essential. Erosive GERD has been identified as a risk factor that contributes to the development of dysphagia and regurgitation in individuals with SSc.

Immune profiling analysis of double-negative T cells in patients with systemic sclerosis

OBJECTIVE

To construct a molecular immune map of patients with systemic sclerosis (SSc) by mass flow cytometry, and compare the number and molecular expression of double-negative T (DNT) cell subsets between patients and healthy controls (HC).

METHODS

Peripheral blood mononuclear cells (PBMCs) were extracted from the peripheral blood of 17 SSc patients and 9 HC. A 42-channel panel was set up to perform mass cytometry by time of flight (CyTOF) analysis for DNT subgroups. Flow cytometry was used to validate subpopulation functions. The clinical data of patients were collected for correlation analysis.

RESULTS

Compared with HC, the number of total DNT cells decreased in SSc patients. Six DNT subsets were obtained from CyTOF analysis, in which the proportion of cluster1 increased, while the proportion of cluster3 decreased. Further analysis revealed that cluster1 was characterized by high expression of CD28 and CCR7, and cluster3 was characterized by high expression of CD28 and CCR5. After in vitro stimulation, cluster1 secreted more IL-4 and cluster3 secreted more IL-10 in SSc patients compared to HC. Clinical correlation analysis suggested that cluster1 may play a pathogenic role while cluster3 may play a protective role in SSc. ROC curve analysis further revealed that cluster3 may be a potential indicator for determining disease activity in SSc patients.

CONCLUSION

We found a new CCR5+CD28+ DNT cell subset, which played a protective role in the pathogenesis of SSc. Key Points • The number of DNT cells decreased in SSc patients' peripheral blood. • DNT cells do not infiltrate in the skin but secrete cytokines to participate in the pathogenesis of SSc. • A CCR5+CD28+ DNT cell population may play a protective role in SSc.

Insight into the role of IRF7 in skin and connective tissue diseases

Interferons (IFNs) are signalling proteins primarily involved in initiating innate immune responses against pathogens and promoting the maturation of immune cells. Interferon Regulatory Factor 7 (IRF7) plays a pivotal role in the IFNs signalling pathway. The activation process of IRF7 is incited by exogenous or abnormal nucleic acids, which is followed by the identification via pattern recognition receptors (PRRs) and the ensuing signalling cascades. Upon activation, IRF7 modulates the expression of both IFNs and inflammatory gene regulation. As a multifunctional transcription factor, IRF7 is mainly expressed in immune cells, yet its presence is also detected in keratinocytes, fibroblasts, and various dermal cell types. In these cells, IRF7 is critical for skin immunity, inflammation, and fibrosis. IRF7 dysregulation may lead to autoimmune and inflammatory skin conditions, including systemic scleroderma (SSc), systemic lupus erythematosus (SLE), Atopic dermatitis (AD) and Psoriasis. This comprehensive review aims to extensively elucidate the role of IRF7 and its signalling pathways in immune cells and keratinocytes, highlighting its significance in skin-related and connective tissue diseases.

Induction of regulatory T cells and efficacy of low-dose interleukin-2 in systemic sclerosis: interventional open-label phase 1-phase 2a study

BACKGROUND

Systemic sclerosis (SSc) is a chronic autoimmune disease, with impaired immune response, increased fibrosis and endothelial dysfunction. Regulatory T cells (Tregs), which are essential to control inflammation, tissue repair and autoimmunity, have a decreased frequency and impaired function in SSc patients. Low-dose interleukin-2 (IL-2LD) can expand and activate Tregs and has, therefore, a therapeutic potential in SSc.

OBJECTIVE

We aimed to assess the safety and biological efficacy of IL-2LD in patients with SSc.

METHODS

As part of the TRANSREG open-label phase IIa basket trial in multiple autoimmune diseases, we studied nine patients with SSc without severe organ involvement. Patients received 1 million international units (MIU)/day of IL-2 for 5 days, followed by fortnightly injections for 6 months. Laboratory and clinical evaluations were performed between baseline and month 6.

RESULTS

At day 8, the primary endpoint (Treg frequency) was reached with a 1.8±0.5-fold increase of Treg levels among CD4+ T lymphocytes (p=0.0015). There were no significant changes in effector T cells nor in B cells. IL-2LD was well tolerated, and no serious adverse events related to treatment occurred. There was a globally stable measurement in the modified Rodnan skin score and Valentini score at month 6. Disease activity and severity measures, the quality of life evaluated by EuroQL-5D-5L and pulmonary function test parameters remained stable during the study period.

CONCLUSION

IL-2LD at a dosage of 1 MIU/day safely and selectively activates and expands Tregs. Clinical signs remain stable during the study period. This opens the door to properly powered phase II efficacy trials investigating IL-2LD therapeutic efficacy in SSc.

Neutrophil-Driven M2-Like Macrophages Are Critical for Skin Fibrosis in a Systemic Sclerosis Model

Systemic sclerosis (SSc) is a challenging autoimmune disease characterized by progressive fibrosis affecting the skin and internal organs. Despite the known infiltration of macrophages and neutrophils, their precise contributions to SSc pathogenesis remain elusive. In this study, we elucidated that CD206hiMHCIIlo M2-like macrophages constitute the predominant pathogenic immune cell population in the fibrotic skin of a bleomycin-induced SSc mouse model. These cells emerged as pivotal contributors to the profibrotic response by orchestrating the production of TGF-β1 through a MerTK signaling-dependent manner. Notably, we observed that neutrophil infiltration was a prerequisite for accumulation of M2-like macrophages. Strategies such as neutrophil depletion or inhibition of CXCR1/2 were proven effective in reducing M2-like macrophages, subsequently mitigating SSc progression. Detailed investigations revealed that in fibrotic skin, neutrophil-released neutrophil extracellular traps were responsible for the differentiation of M2-like macrophages. Our findings illuminate the significant involvement of the neutrophil-macrophage-fibrosis axis in SSc pathogenesis, offering critical information for the development of potential therapeutic strategies.

EGR1 Mediated Reduction of Fibroblast Secreted-TGF-β1 Exacerbated CD8+ T Cell Inflammation and Migration in Vitiligo

Vitiligo is a T cell-mediated depigment skin disease caused by the complex interplay between melanocyte dysfunction, environmental stimulation, and dysregulated immune signals. Transforming growth factor-β1 (TGF-β1), which typically derives from regulatory T cells, has long been identified at low levels in the peripheral system of vitiligo patients. Here, through RNA-sequencing and transcription factor enrichment, we revealed that in response to CD8+ T cell-secreted interferon-gamma (IFN-γ), stromal fibroblast downregulates early growth response 1 (EGR1) activity, leading to TGF-β1 deficiency. The defective immune regulation loop further exacerbated local CD8+ T cell inflammation and promoted inflammatory cell migration in vitiligo. Thus, fibroblast-derived TGF-β1 plays an important stromal signal in vitiligo pathogenesis.

Systemic sclerosis associated respiratory involvement: Scopus-based analysis of articles in 2013-2022

BACKGROUND

Systemic sclerosis (SSc), a complex autoimmune disorder, manifests as a convergence of rheumatologic, dermatologic, and pulmonary challenges. Among the severe complications contributing to morbidity and mortality are SSc Associated Interstitial Lung Disease (SSc-ILD) and pulmonary hypertension. Over the past decade, research on pulmonary involvement in SSc has intensified, leading to a heightened understanding of its pathogenesis, diagnostic methods, and therapeutic strategies.

AIM

This study aims to provide a data-driven overview of the current state of systemic sclerosis research, identifying emerging trends and fostering informed decisions regarding resource allocation and research priorities.

METHODS

A literature search was conducted in the Scopus database, using MESH keywords such as "systemic sclerosis" AND "lungs" OR "pulmonary hypertension" OR "interstitial lung disease". After applying exclusion criteria, a thorough analysis was performed, considering factors such as document category, authorship, journal source, citation frequency, country of publication, language, and keywords. The bibliometric analysis utilized Scopus as the preferred database, leveraging its extensive coverage, user-friendly interface, and commitment to data accuracy. Visual networks were constructed using VOSviewer software to map the relationships between keywords, countries, and authors. Altmetric Attention Scores (AAS) were employed to assess the social impact of articles.

RESULTS

The analysis revealed a total of 2538 scholarly items, with 55.7% identified as open access. The USA (n = 532), Italy (n = 458), France (n = 304), Japan (n = 271), and the UK (n = 236) emerged as primary contributors, with English being the predominant language. A notable upward tendency in annual publication and citation scores indicated sustained interest and relevance in SSc-ILD research. The top journals, including Rheumatology United Kingdom, Clinical and Experimental Rheumatology, Clinical Rheumatology, Arthritis and Rheumatology, and Journal of Rheumatology, played a pivotal role in scholarly output. Original Articles (n = 1795; 70.7%) constituted the majority of publications, followed by Reviews, Letters, Notes, and Editorials. The analysis of publication impact within different scholarly formats revealed varying citation patterns, with Original Articles and Reviews leading in influence. The identification of influential research hubs and key contributors provided insights into collaborative efforts and geographic distribution. A strong correlation (rho = 0.612, p < 0.001) was observed between the quantity of Mendeley readers and the citations received by scholarly articles.

CONCLUSION

This bibliometric analysis offers a comprehensive overview of SSc-ILD research, highlighting its dynamic and interdisciplinary nature. The surge in publications, citation scores, and the identification of key contributors underscore the continued relevance and impact of this field. The nuanced relationships between social attention and scientific recognition, as revealed by Mendeley readership and AAS, contribute to a deeper understanding of the multifaceted nature of scholarly impact.

Systemic Sclerosis in Individuals With Exposure to World Trade Center Ground Zero Rescue and Recovery Efforts: A Case Series

OBJECTIVE

The World Trade Center (WTC) attack in New York resulted in a dust plume containing silica, hydrocarbons, and asbestos. Autoimmune disorders have been reported among those with WTC site exposure. The characteristics of individuals developing systemic sclerosis (SSc) have not been previously described. The purpose of this study was to describe the features of patients with SSc with WTC exposure.

METHODS

Data were collected from 11 patients with SSc or SSc spectrum conditions who reported exposure to the WTC site. Seven patients completed an exposure assessment.

RESULTS

Of the 11 patients, the majority (n = 8) were female. The median (range) for age at diagnosis was 46 (36-75) years, time between exposure and first non-Raynaud phenomenon SSc symptom was 8 (1-19) years, and time between exposure and diagnosis was 11 (2-18) years. Fifty-five percent had SSc onset > 5 years from WTC exposure. Five patients had limited cutaneous SSc, 3 patients had diffuse cutaneous SSc, 1 patient with SSc features met criteria for mixed connective tissue disease (CTD), and 2 patients had undifferentiated CTD with features of SSc. Four patients had overlapping features with other CTDs. Interstitial lung disease (ILD) was present in 10 patients. Five of 11 patients had a history of tobacco use. Seven of 7 patients who completed the questionnaire reported other hazardous exposures outside of WTC. Of these, only 2 patients reported personal protective equipment use.

CONCLUSION

A high frequency of ILD and overlap features were observed among patients with SSc with WTC exposure. Future studies are needed to characterize this association.

MicroRNA-21a-5p inhibition alleviates systemic sclerosis by targeting STAT3 signaling

BACKGROUND

MicroRNA (miRNA)-21-5p participates in various biological processes, including cancer and autoimmune diseases. However, its role in the development of fibrosis in the in vivo model of systemic sclerosis (SSc) has not been reported. This study investigated the effects of miRNA-21a-5p overexpression and inhibition on SSc fibrosis using a bleomycin-induced SSc mouse model.

METHODS

A murine SSc model was induced by subcutaneously injecting 100 μg bleomycin dissolved in 0.9% NaCl into C57BL/6 mice daily for 5 weeks. On days 14, 21, and 28 from the start of bleomycin injection, 100 μg pre-miRNA-21a-5p or anti-miRNA-21a-5p in 1 mL saline was hydrodynamically injected into the mice. Fibrosis analysis was conducted in lung and skin tissues of SSc mice using hematoxylin and eosin as well as Masson's trichrome staining. Immunohistochemistry was used to examine the expression of inflammatory cytokines, phosphorylated signal transducer and activator of transcription-3 (STAT3) at Y705 or S727, and phosphatase and tensin homologue deleted on chromosome-10 (PTEN) in skin tissues of SSc mice.

RESULTS

MiRNA-21a-5p overexpression promoted lung fibrosis in bleomycin-induced SSc mice, inducing infiltration of cells expressing TNF-α, IL-1β, IL-6, or IL-17, along with STAT3 phosphorylated cells in the lesional skin. Conversely, anti-miRNA-21a-5p injection improved fibrosis in the lung and skin tissues of SSc mice, reducing the infiltration of cells secreting inflammatory cytokines in the skin tissue. In particular, it decreased STAT3-phosphorylated cell infiltration at Y705 and increased the infiltration of PTEN-expressing cells in the skin tissue of SSc mice.

CONCLUSION

MiRNA-21a-5p promotes fibrosis in an in vivo murine SSc model, suggesting that its inhibition may be a therapeutic strategy for improving fibrosis in SSc.

Neurological, cardiac, musculoskeletal, and renal manifestations of scleroderma along with insights into its genetics, pathophysiology, diagnostic, and therapeutic updates

Background

Scleroderma, also referred to as systemic sclerosis, is a multifaceted autoimmune condition characterized by abnormal fibrosis and impaired vascular function. Pathologically, it encompasses the persistent presence of inflammation, abnormal collagen buildup, and restructuring of blood vessels in various organs, resulting in a wide range of clinical symptoms. This review incorporates the most recent scientific literature on scleroderma, with a particular emphasis on its pathophysiology, clinical manifestations, diagnostic approaches, and treatment options.

Methodology

A comprehensive investigation was carried out on numerous databases, such as PubMed, MEDLINE, Scopus, Web of Science, and Google Scholar, to collect pertinent studies covering diverse facets of scleroderma research.

Results

Scleroderma presents with a range of systemic manifestations, such as interstitial lung disease, gastrointestinal dysmotility, Raynaud's phenomenon, pulmonary arterial hypertension, renal complications, neurological symptoms, and cardiac abnormalities. Serological markers, such as antinuclear antibodies, anti-centromere antibodies, and anti-topoisomerase antibodies, are important for classifying diseases and predicting their outcomes.

Discussion

The precise identification of scleroderma is crucial for promptly and correctly implementing effective treatment plans. Treatment approaches aim to improve symptoms, reduce complications, and slow down the progression of the disease. An integrated approach that combines pharmacological agents, including immunosuppressants, endothelin receptor antagonists, and prostanoids, with nonpharmacological interventions such as physical and occupational therapy is essential for maximizing patient care.

Conclusion

Through the clarification of existing gaps in knowledge and identification of emerging trends, our goal is to improve the accuracy of diagnosis, enhance the effectiveness of therapeutic interventions, and ultimately enhance the overall quality of life for individuals suffering from scleroderma. Ongoing cooperation and creative research are necessary to advance the field and achieve improved patient outcomes and new therapeutic discoveries.

Validity and reliability of measurement of peripheral oxygen saturation during the 6-Minute Walk Test in patients with systemic sclerosis

Peripheral oxygen saturation (SpO2) using the fingers may have important limitations due to Raynaud's phenomenon and sclerodactyly in patients with systemic sclerosis (SSc). Sensors located at more central body positions may be more accurate as these as less prone to Raynaud attacks. To determine the validity and reliability of the SpO2 measured at the finger, forehead, and earlobe during the 6-Minute Walk Test (6MWT). Eighty two patients with SSc had an arterial line placed while performing the 6MWT. Peripheral oxygen saturation was simultaneously measured by finger, forehead, and earlobe sensors and compared to the arterial oxygen saturation (SaO2) measured before and after the 6MWT. 40 patients repeated the 6MWT one week later to determine re-test reliability. We used Bland-Altman plots to display the agreement between SpO2 and SaO2. The intraclass correlation coefficient for repeated measurement of minimum SpO2 was calculated. The mean difference between SpO2 and SaO2 after the 6MWT was - 3% (SD: ± 5), 0% (SD: ± 2), and 1% (SD: ± 2) for the finger, forehead, and earlobe, respectively. The minimum SpO2 measured at the finger demonstrated the poorest re-test reliability: The ICC (95% CI) showed good agreement using the ear and forehead probe (ICCear = 0.89 [95% CI 0.80; 0.94]; ICCforehead = 0.77 [95% CI 0.60; 0.87]), while a modest reliability was found using the finger probe (ICCfinger = 0.65 95% CI [0.43; 0.80]). SpO2 should be measured using either the earlobe or forehead during the 6MWT in patients with SSc. Clinical Trials.Gov (NCT04650659).

Emerging therapeutic targets in systemic sclerosis

Systemic sclerosis is an autoimmune connective tissue disease which is characterised by vascular perturbations, inflammation, and fibrosis. Although huge progress recently into the underlying molecular pathways that are perturbed in the disease, currently no therapy exists that targets the fibrosis element of the disease and consequently there is a huge unmet medical need. Emerging studies reveal new dimensions of complexity, and multiple aberrant pathways have been uncovered that have shed light on disturbed signalling in the disease, primarily in inflammatory pathways that can be targeted with repurposed drugs. Pre-clinical animal models using these inhibitors have yielded proof of concept for targeting these signalling systems and progressing to clinical trials. This review will examine the recent evidence of new perturbed pathways in SSc and how these can be targeted with new or repurposed drugs to target a currently intractable disease.

Different Kynurenine Pathway Dysregulation in Systemic Sclerosis in Men and Women

Systemic sclerosis (SSc), a predominantly female-affected systemic autoimmune disease, requires tailored treatment strategies contingent on organ involvement and symptom severity. Given SSc's inflammatory nature, the involvement of the kynurenine pathway (KP) in its pathophysiology is underexplored. Our study aimed to investigate sex-related differences in KP activation among SSc patients and assess the impact of angiotensin-converting enzyme (ACE) inhibitors and estimated glomerular filtration rate (eGFR) on KP metabolite concentrations. We enrolled 48 SSc patients and 53 healthy controls, quantifying KP metabolites (tryptophan (TRP), kynurenine (KYN), and kynurenic acid (KYNA)) in serum via high-performance liquid chromatography. Separate multivariate analyses of covariance (MANCOVAs) for women and men were performed to ascertain mean differences between patients and healthy controls while correcting for age. For our secondary objective, we conducted a MANCOVA to explore disparities in ACE inhibitor users and non-users among patients, with BMI correction. Our findings revealed decreased TRP concentrations but increased KYNA/TRP ratio and KYN/TRP ratio in both male and female SSc patients compared to their respective controls. Unlike women, SSc males exhibited higher KYN concentrations and decreased KYNA/KYN ratio relative to their controls. Additionally, SSc patients using ACE inhibitors had higher serum KYNA levels than non-users. Notably, we established a significant correlation between eGFR and KYNA in SSc patients. These results indicate differential KP activation in male and female SSc patients, with males demonstrating heightened KP activation. While ACE inhibitors may influence the KP in SSc patients, further research is necessary to comprehensively understand their impact on symptoms and prognosis in the context of these KP alterations.

Single-cell epigenomic dysregulation of Systemic Sclerosis fibroblasts via CREB1/EGR1 axis in self-assembled human skin equivalents

Systemic sclerosis (SSc) is an autoimmune disease characterized by skin fibrosis, internal organ involvement and vascular dropout. We previously developed and phenotypically characterized an in vitro 3D skin-like tissue model of SSc, and now analyze the transcriptomic (scRNA-seq) and epigenetic (scATAC-seq) characteristics of this model at single-cell resolution. SSc 3D skin-like tissues were fabricated using autologous fibroblasts, macrophages, and plasma from SSc patients or healthy control (HC) donors. SSc tissues displayed increased dermal thickness and contractility, as well as increased α-SMA staining. Single-cell transcriptomic and epigenomic analyses identified keratinocytes, macrophages, and five populations of fibroblasts (labeled FB1 - 5). Notably, FB1 APOE-expressing fibroblasts were 12-fold enriched in SSc tissues and were characterized by high EGR1 motif accessibility. Pseudotime analysis suggests that FB1 fibroblasts differentiate from a TGF-β1-responsive fibroblast population and ligand-receptor analysis indicates that the FB1 fibroblasts are active in macrophage crosstalk via soluble ligands including FGF2 and APP. These findings provide characterization of the 3D skin-like model at single cell resolution and establish that it recapitulates subsets of fibroblasts and macrophage phenotypes observed in skin biopsies.

Novel and potential future therapeutic options in systemic autoimmune diseases

Autoimmune inflammation is caused by the loss of tolerance to specific self-antigens and can result in organ-specific or systemic disorders. Systemic autoimmune diseases affect a significant portion of the population with an increasing rate of incidence, which means that is essential to have effective therapies to control these chronic disorders. Unfortunately, several patients with systemic autoimmune diseases do not respond at all or just partially respond to available conventional synthetic disease-modifying antirheumatic drugs and targeted therapies. However, during the past few years, some new medications have been approved and can be used in real-life clinical settings. Meanwhile, several new candidates appeared and can offer promising novel treatment options in the future. Here, we summarize the newly available medications and the most encouraging drug candidates in the treatment of systemic lupus erythematosus, rheumatoid arthritis, Sjögren's disease, systemic sclerosis, systemic vasculitis, and autoimmune myositis.

Association of serum Ly6/PLAUR domain-containing protein 1 levels with skin sclerosis in systemic sclerosis

Systemic sclerosis (SSc) is a connective tissue disease characterized by aberrant immune activation, vascular injury, and fibrosis of the skin and internal organs. Ly6/PLAUR domain-containing protein 1 (LYPD1) was reported to be secreted and to have various physiological functions such as anti-angiogenic effects. Here we investigated serum LYPD1 levels in SSc patients and the association of serum LYPD1 levels with clinical features of SSc. Serum samples were obtained from 75 SSc patients and 22 healthy individuals as controls. We measured serum LYPD1 levels using enzyme-linked immunosorbent assay kits. Then, the relationship between serum LYPD1 levels and clinical features of SSc was analyzed. Serum LYPD1 levels in diffuse cutaneous SSc (dcSSc) patients were significantly higher than those in the limited cutaneous SSc (lcSSc) patients (median [25-75th percentiles], 1693.43 [1086.61-1917.57] vs. 904.55 [714.356-1285.56] pg/mL), while there were no significant differences in the serum LYPD1 levels between lcSSc and healthy controls (904.55 [714.356-1285.56] vs. 750.71 pg/mL [544.00-912.14]). Further analysis revealed that serum LYPD1 levels in patients correlated with skin thickness scores and serum interleukin (IL)-6 levels, which were known to reflect the extent of skin thickening in SSc. Moreover, serum LYPD1 levels showed a decrease with improvement in skin thickness after treatment, along with a decrease in serum IL-6 levels. These results indicate that LYPD1 might be a potential marker for monitoring skin sclerosis and evaluating the efficacy of skin fibrosis treatment in SSc patients.

S100A4 a classical DAMP as a therapeutic target in fibrosis

Fibrosis regardless of aetiology is characterised by persistently activated myofibroblasts that are contractile and secrete excessive amounts of extracellular matrix molecules that leads to loss of organ function. Damage-Associated Molecular Patterns (DAMPs) are endogenous host-derived molecules that are released from cells dying or under stress that can be triggered by a variety of insults, either chemical or physical, leading to an inflammatory response. Among these DAMPs is S100A4, part of the S100 family of calcium binding proteins that participate in a variety of cellular processes. S100A4 was first described in context of cancer as a pro-metastatic factor. It is now appreciated that aside from its role in cancer promotion, S100A4 is intimately involved in tissue fibrosis. The extracellular form of S100A4 exerts its effects through multiple receptors including Toll-Like Receptor 4 and RAGE to evoke signalling cascades involving downstream mediators facilitating extracellular matrix deposition and myofibroblast generation and can play a role in persistent activation of myofibroblasts. S100A4 may be best understood as an amplifier of inflammatory and fibrotic processes. S100A4 appears critical in systemic sclerosis pathogenesis and blocking the extracellular form of S100A4 in vivo in various animal models of disease mitigates fibrosis and may even reverse established disease. This review appraises S100A4's position as a DAMP and its role in fibrotic conditions and highlight therapeutically targeting this protein to halt fibrosis, suggesting that it is a tractable target.

Measurement equivalence of the English and French versions of the self-efficacy to manage chronic disease scale: a Scleroderma Patient-Centered Intervention Network (SPIN) study

PURPOSE

The Self-Efficacy to Manage Chronic Disease (SEMCD) scale is widely used, including in systemic sclerosis (SSc). The SEMCD has been validated in SSc, but the metric equivalence of the English and French versions has not been assessed (i.e., whether psychometric properties are equivalent across English and French).

METHODS

Participants were adults from the Scleroderma Patient-Centered Intervention Network (SPIN) Cohort (N = 2159) who completed baseline measures in English (n = 1473) or French (n = 686) between May 2014 to July 2020. Analyses assessed internal consistency reliability via Cronbach's alpha and McDonald's omega, convergent validity via Pearson's correlations, structural validity via confirmatory factor analysis (CFA), and differential item functioning via the Multiple-Indicator Multiple-Cause (MIMIC) model.

RESULTS

Internal consistency reliability was high in English (α = .93, ω = .93) and French (α = .92, ω = .93). All correlations between the SEMCD and measures of health outcomes were moderate to large, statistically significant, and in the hypothesized direction in both languages. The CFA demonstrated that the one-factor model of self-efficacy, overall, fit reasonably well (CFI = .96, TLI = .93, SRMR = .03, RMSEA = .14). Standardized factor loadings were large (.76 to .88). Three items displayed statistically significant uniform DIF and all six displayed nonuniform DIF; all DIF was of minimal magnitude. Comparison of unadjusted and DIF-adjusted models indicated that DIF did not meaningfully impact total score (ICC = 0.999, r = 0.999).

CONCLUSION

Scores from English- and French-speaking adults with SSc can be combined for analysis or compared.

Psychometric evaluation of the Pain Vigilance and Awareness Questionnaire (PVAQ) in fibromyalgia: Confirmatory factor analysis and the development of a Swedish 8-item version

BACKGROUND

Excessive attention to pain, or hypervigilance, is associated with negative outcomes in chronic pain conditions such as fibromyalgia. The Pain Vigilance and Awareness Questionnaire (PVAQ) is a self-report questionnaire to measure attention to pain. This study aimed to evaluate the psychometric properties of a Swedish version of the PVAQ.

METHODS

Psychometric evaluation on cross-sectional data derived from a clinical trial for fibromyalgia (N = 274). We evaluated item characteristics, factor structure in a confirmatory factor analytic framework, internal consistency, and construct validity in terms of correlations with other clinical variables.

RESULTS

Though confirmatory factor analysis did not result in a satisfactory solution for the full 16-item scale, acceptable two-factor solutions could be based on either nine or eight items (the PVAQ-9 and PVAQ-8). Internal consistency for both the PVAQ-9 and PVAQ-8 were good to excellent, and associations with pain catastrophizing, anxiety, depression, disability, and overall fibromyalgia impact were largely supportive of construct validity. An unexpected result was that, contrary to previous findings, no version of the PVAQ correlated consistently with pain intensity.

CONCLUSIONS

The Swedish PVAQ-9 and PVAQ-8 appear to have acceptable psychometric properties when administered online to individuals with fibromyalgia. The PVAQ-8 may be preferable due to being shorter and including an equal number of items per factor. Replication is warranted.

SIGNIFICANCE

This study evaluated the psychometric properties of a Swedish translation of the PVAQ in individuals with fibromyalgia. No convincing factor structure was found for the 16-item version. We could, however, confirm the factor structure of an established 9-item version (the PVAQ-9), and recommend further use of a new 8-item version (the PVAQ-8). In summary, the PVAQ exhibited more convincing psychometric properties when the number of items was roughly cut in half.

Factors associated with satisfaction with social roles and activities among people with systemic sclerosis: a Scleroderma Patient-centered Intervention Network (SPIN) cohort cross-sectional study

OBJECTIVE

The objectives were to (1) compare satisfaction with social roles and activities in a large multinational systemic sclerosis (SSc) cohort to general population normative data and (2) identify sociodemographic, lifestyle and SSc disease factors associated with satisfaction with social roles and activities.

METHODS

Participants in the Scleroderma Patient-centered Intervention Network Cohort completed the Patient Reported Outcomes Information System Version 2 satisfaction with social roles and activities domain questionnaire. Multivariable regression was used to assess associations with sociodemographic, lifestyle and disease factors.

RESULTS

Among 2385 participants, mean satisfaction with social roles and activities T-score (48.1, SD=9.9) was slightly lower than the US general population (mean=50, SD=10). Factors independently associated with satisfaction were years of education (0.54 per SD, 95% CI 0.14 to 0.93); non-White race or ethnicity (-1.13, 95% CI -2.18 to -0.08); living in Canada (-1.33, 95% CI -2.40 to -0.26 (reference USA)) or the UK (-2.49, 95% CI -3.92 to -1.06); body mass index (-1.08 per SD, 95% CI -1.47 to -0.69); gastrointestinal involvement (-3.16, 95% CI -4.27 to -2.05); digital ulcers (-1.90, 95% CI -3.05 to -0.76); moderate (-1.62, 95% CI -2.78 to -0.45) or severe (-2.26, 95% CI -3.99 to -0.52) small joint contractures; interstitial lung disease (-1.11, 95% CI -1.97 to -0.25); pulmonary arterial hypertension (-2.69, 95% CI -4.08 to -1.30); rheumatoid arthritis (-2.51, 95% CI -4.28 to -0.73); and Sjogren's syndrome (-2.42, 95% CI -3.96 to -0.88).

CONCLUSION

Mean satisfaction with social roles and activities is slightly lower in SSc than the general population and associated with multiple sociodemographic and disease factors.

Effects of B Cell Depletion by CD19-Targeted Chimeric Antigen Receptor T Cells in a Murine Model of Systemic Sclerosis

OBJECTIVE

Our goal was to study the tolerance and efficacy of two B cell depletion strategies, including one with CD19-targeted chimeric antigen receptor (CAR) T cells, in a preclinical model mimicking the severe lung damages observed in systemic sclerosis.

METHODS

B cell depletion strategies were evaluated in the Fra-2 transgenic (Tg) mouse model. We considered a first group of 16 untreated mice, a second group of 15 mice receiving a single dose of anti-CD20 monoclonal antibody (mAb), and a third group of 8 mice receiving CD19-targeted CAR-T cells in combination with anti-CD20 monoclonal antibody. After six weeks of clinical evaluation, different validated markers of inflammation, lung fibrosis, and pulmonary vascular remodeling were assessed.

RESULTS

CD19-targeted CAR-T cells infusion in combination with anti-CD20 mAb resulted in a deeper B cell depletion than anti-CD20 mAb alone in the peripheral blood and lesional lungs of Fra-2 Tg mice. CAR-T cell infusion worsened the clinical score and increased mortality in Fra-2 Tg mice. In line with the above findings, CAR-T cell infusion significantly increased lung collagen content, the histological fibrosis score, and right ventricular systolic pressure. CAR-T cells accumulated in lesional lungs and promoted T activation and inflammatory cytokine production. Treatment with anti-CD20 mAb in monotherapy had no impact on lung inflammation-driven fibrosis and pulmonary hypertension.

CONCLUSION

B cell therapies failed to show efficacy in the Fra2 Tg mice. The exacerbated Fra-2 lung inflammatory burden stimulated accumulation and expansion of activated CD19-targeted CAR-T cells, secondarily inducing T cell activation and systemic inflammation, finally leading to disease worsening.

Deficiency and altered phenotype of mucosal-associated invariant T cells in systemic sclerosis

Objective

Systemic sclerosis is an autoimmune disease characterized by fibrosis of the skin and internal organs including the lung. Mucosal-associated invariant T cells are innate-like T lymphocytes able to produce various cytokines and cytotoxic mediators such as granzyme B. A large body of evidence supports a role of mucosal-associated invariant T cells in autoimmune disease but more recent reports suggest also a potential role in fibrotic conditions. Therefore, we herein addressed the question as whether mucosal-associated invariant T cells may have an altered profile in systemic sclerosis.

Methods

Mucosal-associated invariant T cell frequency was analyzed by flow cytometry, using fresh peripheral blood from 74 consecutive systemic sclerosis patients who were compared to 44 healthy donors. In addition, in-depth mucosal-associated invariant T cell phenotype and function were analyzed in unselected 29 women with systemic sclerosis who were compared to 23 healthy women donors.

Results

Proportion of circulating mucosal-associated invariant T cells was significantly reduced by 68% in systemic sclerosis compared to healthy donors (0.78% in systemic sclerosis vs 2.5%, p < 0.0001). Within systemic sclerosis subsets, mucosal-associated invariant T cells were reduced in patients with interstitial lung disease (systemic sclerosis-interstitial lung disease) (0.56% vs 0.96% in patients without interstitial lung disease, p = 0.04). Moreover, in systemic sclerosis patients, mucosal-associated invariant T cells displayed an activated phenotype indicated by markedly increased CD69+ mucosal-associated invariant T cell frequency (20% mucosal-associated invariant T cell CD69+ compared to 9.4% in healthy donors, p = 0.0014). Interestingly, mucosal-associated invariant T cells from systemic sclerosis-interstitial lung disease patients had a more pronounced altered phenotype compared to systemic sclerosis without interstitial lung disease with a correlation between mucosal-associated invariant T cells expressing CCR6+ and mucosal-associated invariant T cell frequency (r = 0.8, p = 0.006).

Conclusion

Circulating mucosal-associated invariant T cells were reduced and exhibited an activated phenotype in systemic sclerosis patients. This peripheral mucosal-associated invariant T cell deficiency may be related to enhanced apoptosis and/or homing in inflamed tissue, particularly in systemic sclerosis-interstitial lung disease patients.

Systemic sclerosis patients with negative antinuclear antibodies have distinctive clinical manifestations: a multicenter CRDC cohort in China

BACKGROUND

The presence of circulating antinuclear antibodies (ANAs) is a hallmark of immune dysregulation in patients with systemic sclerosis (SSc).

OBJECTIVE

A variety of ANAs are associated with unique sets of disease manifestations and are widely used in clinical practice in SSc. This study aimed to investigate the clinical features of SSc patients negative for ANAs in a Chinese Rheumatism Data Center (CRDC) multicenter cohort in China.

METHODS

Patients were prospectively recruited between April 2008 and June 2019 from 154 clinical centers nationwide, and all cases fulfilled the 2013 ACR/EULAR classification criteria for systemic sclerosis. Results for antinuclear antibodies were intensively collected. Demographic, clinical, and laboratory data were compared between ANA-positive SSc patients and those negative for ANAs.

RESULTS

Antinuclear antibodies were detected in 2129 of 2809 patients enrolled in the study; 4.2% of patients were negative. There were more males among ANA-negative SSc patients (29/60 vs. 294/1746, p < 0.001). The incidence of certain critical organ involvement, including gastroesophageal reflux (5.6% vs. 18.5%, p = 0.002), interstitial lung disease (65.2% vs. 77.9%, p = 0.015), and pulmonary arterial hypertension (11.5% vs. 29.0%, p = 0.006) was significantly lower in ANA-negative patients than in ANA-positive patients. The proportion of abnormal erythrocyte sedimentation rate (32.4% vs. 47.6%, p = 0.013) and IgG elevation (14.3% vs. 37.0%, p = 0.003), an indicator of disease activity, was significantly lower in ANA-negative patients than in ANA-positive patients.

CONCLUSION

Antinuclear antibodies are strongly associated with the clinical manifestations of systemic sclerosis, with ANA-negative SSc patients tending to exhibit relatively milder disease.

Performance of myotonometer in the assessment of skin involvement in systemic sclerosis

OBJECTIVES

A clinically practical tool to assess skin biomechanical properties rapidly and accurately is still lacking. Our aim was to examine the intra- and inter-observer reproducibility of a myotonometer for objective skin property assessment in systemic sclerosis (SSc), comparing it with the modified Rodnan skin score (mRSS), and distinguishing patients from healthy controls.

METHOD

Thirty-four patients (21 limited and 13 diffuse SSc), and 31 age and gender-matched healthy controls were enrolled. Skin tone and stiffness were measured at four different anatomical sites (the forearm, hand, leg, and foot) using a myotonometer. The correlation between the mRSS and skin properties was assessed. Also, hand functionality was evaluated for possible correlations between the variables. The differences in skin properties between dcSSc and lcSSc patients, and healthy controls were assessed using variance analysis.

RESULTS

Intra- and inter-examiner reproducibility were excellent (ICC = 0.70 to 0.98) for tone and stiffness except for non-dominant hand tone, which showed good reliability (ICC = 0.64 to 0.74). Stiffness and tone values of the hands, forearms, and feet significantly correlated with mRSS total score (r = 0.40 to 0.71, p < 0.05). Additionally, tone and stiffness of the hands and forearms moderately correlated with hand function (p < 0.05). Tone and stiffness values increased in patients with dcSSc compared to healthy controls, or patients with lcSSc, at the hands, forearms, and legs (p < 0.05).

CONCLUSIONS

Our findings emphasize the potential utility of the myotonometer for assessing skin properties and differentiating SSc patients from controls, demonstrating its promise as a valuable clinical evaluation tool in this context. Key Points •The myotonometer displayed excellent intra- and inter-examiner reproducibility for assessing skin properties. •Skin tone and stiffness parameters well correlated with the mRSS scores. •The myotonometer can distinguish patients with diffuse cutaneous SSc from healthy controls.

Part I: Epidemiology, pathophysiology, and clinical considerations of primary and secondary Raynaud's phenomenon

Raynaud's phenomenon (RP) is a relatively common disease with both primary and secondary forms. It is well understood as a vasospastic condition affecting the acral and digital arteries, resulting in characteristic, well-demarcated color changes typically in the hands and feet in response to cold or stress. Secondary RP (SRP) has been described in association with a variety of rheumatologic and nonrheumatologic diseases, environmental exposures, and/or medications. While both primary RP and SRP may impact the quality of life, SRP may lead to permanent and potentially devastating tissue destruction when undiagnosed and untreated. It is therefore crucial for dermatologists to distinguish between primary and secondary disease forms early in clinical evaluation, investigate potential underlying causes, and risk stratify SRP patients for the development of associated autoimmune connective tissue disease. The epidemiology, pathogenesis, and clinical presentation and diagnosis of both forms of RP are described in detail in this review article.

Tree shrews as a new animal model for systemic sclerosis research

Objective

Systemic sclerosis (SSc) is a chronic systemic disease characterized by immune dysregulation and fibrosis for which there is no effective treatment. Animal models are crucial for advancing SSc research. Tree shrews are genetically, anatomically, and immunologically closer to humans than rodents. Thus, the tree shrew model provides a unique opportunity for translational research in SSc.

Methods

In this study, a SSc tree shrew model was constructed by subcutaneous injection of different doses of bleomycin (BLM) for 21 days. We assessed the degree of inflammation and fibrosis in the skin and internal organs, and antibodies in serum. Furthermore, RNA sequencing and a series of bioinformatics analyses were performed to analyze the transcriptome changes, hub genes and immune infiltration in the skin tissues of BLM induced SSc tree shrew models. Multiple sequence alignment was utilized to analyze the conservation of selected target genes across multiple species.

Results

Subcutaneous injection of BLM successfully induced a SSc model in tree shrew. This model exhibited inflammation and fibrosis in skin and lung, and some developed esophageal fibrosis and secrum autoantibodies including antinuclear antibodies and anti-scleroderma-70 antibody. Using RNA sequencing, we compiled skin transcriptome profiles in SSc tree shrew models. 90 differentially expressed genes (DEGs) were identified, which were mainly enriched in the PPAR signaling pathway, tyrosine metabolic pathway, p53 signaling pathway, ECM receptor interaction and glutathione metabolism, all of which are closely associated with SSc. Immune infiltration analysis identified 20 different types of immune cells infiltrating the skin of the BLM-induced SSc tree shrew models and correlations between those immune cells. By constructing a protein-protein interaction (PPI) network, we identified 10 hub genes that were significantly highly expressed in the skin of the SSc models compared to controls. Furthermore, these genes were confirmed to be highly conserved in tree shrews, humans and mice.

Conclusion

This study for the first time comfirmed that tree shrew model of SSc can be used as a novel and promising experimental animal model to study the pathogenesis and translational research in SSc.

Nephrotic syndrome due to focal segmental glomerulosclerosis complicating scleroderma: a case report

BACKGROUND

Systemic scleroderma (SSc) is an insidious autoimmune connective tissue disorder with multiorgan involvement. Renal involvement is one of the important causes of morbidity and mortality in scleroderma; however, nephrotic syndrome is reported rarely in association with SSc. We present a patient with SSc who developed focal segmental glomerulosclerosis (FSGS) as a complication of scleroderma.

CASE PRESENTATION

A 59 year old Caucasian female patient, with a known history of diffuse systemic sclerosis from 8 years, presented to our clinic with symptoms of anasarca and weight gain. Her physical examination was unremarkable except for periorbital and extremity edema. Her biochemistry assessment revealed decreased serum albumin levels and elevated serum creatinine levels. A renal biopsy was performed, which showed histopathological patterns of FSGS type of nephrotic syndrome. After administration of high doses of steroid and rituximab in the course of her treatment for 6 months, her symptoms and proteinuria were improved without the occurrence of scleroderma renal crises.

CONCLUSION

SSc is a complex multisystemic autoimmune disorder. SRC is the most prominent renal involvement in SSc, but other renal pathologies may also occur. Each patient should be precisely investigated since managing these renal conditions can differ significantly. Nephrotic syndrome is a rare complication of SSc, which could be managed with prompt diagnosis and steroid administration.