Current advances in the treatment of systemic sclerosis

Upregulation of GPX4 drives ferroptosis resistance in scleroderma skin fibroblasts

The pathogenesis of systemic sclerosis (SSC) fibrosis involves the rapid proliferation of skin fibroblasts, and current anti-fibrotic treatments are limited. This study investigated the relationship between ferroptosis and SSC skin fibroblasts. We observed that erastin-induced ferroptosis was suppressed in SSC fibroblasts. RSL3, a direct inhibitor of Glutathione Peroxidase 4 (GPX4), significantly reduced the viability of the fibroblasts, and upregulation of GPX4 in the SSC fibroblasts contributed to ferroptosis resistance. Furthermore, we demonstrated that transferrin receptor 1 (TfR1) was a crucial transporter for iron deposition in the fibroblasts. Collectively, our results highlight that GPX4 inhibition could enhance the sensitivity to ferroptosis by SSC fibroblasts, which showed distinct characteristics of iron metabolism that were not observed in normal fibroblasts in this study. Taken together, these results suggest that targeting ferroptosis could be a therapeutic strategy for the treatment of SSC.

Growth arrest-specific protein 6 as a marker of nephritis in systemic sclerosis and juvenile systemic lupus erythematosus patients

Background: Renal impairments commonly occur as a complication of autoimmune connective tissue diseases (CTDs). Therefore, early nephritis prediction is vital for patient outcomes. Growth Arrest-Specific Protein 6 (GAS6) was found to be upregulated in many types of inflammatory renal disease, including diabetic nephropathy.Aim: To evaluate GAS6 as a predictor of renal impairment in adults with systemic sclerosis (SSc) and children with systemic lupus Erythematosus (SLE).Methods: The study included 60 patients with SSc and 40 children with SLE. The serum level of GAS6 was measured using the ELISA technique. In adults with SSc, total proteins in 24-h urine concentration of >300 mg/24 h indicated renal inflammation, while in children with SLE, nephritis was diagnosed by abnormal renal pathology.Results: In SSc patients, GAS6 significantly increased in patients with proteinuria. GAS6 is an independent predictor of nephritis with an odds ratio (OR) of 1.06 and a 95% confidence interval (CI) of 1.0-1.1. at cutoff 12.2 ng/mL GAS6 predicted proteinuria with sensitivity 86.7% (95% CI: 59.5% to 98.3%), specificity 57.8% (95% CI: 42.1% to 72.3%), positive predictive value 40.6% (95% CI: 31.5% to 50.4%), negative predictive value 92.9% (95% CI: 77.7% to 97.73%), and accuracy 65.0% (95% CI: 51.6% to 76.9%). In SLE patients, Serum GAS6 did not differ significantly between children with and without lupus nephritis.Conclusion: GAS6 is an independent predictor of nephritis in patients with SSc. However, there is no association between GAS6 and nephritis in juvenile patients with SLE.

Let‑7f‑5p Regulated by Hsa_circ_0000437 Ameliorates Bleomycin-Induced Skin Fibrosis

The current treatment of skin fibrosis is limited in its effectiveness due to a lack of understanding of the underlying mechanisms. Previous research has shown a connection between microRNAs (miRNAs) and the development of skin fibrosis. Therefore, investigating miRNA for the treatment of skin fibrotic diseases is highly important and merits further exploration. In this study, we have discovered that let-7f-5p could suppress the proliferation, migration, and expression of collagen type I alpha 1 (COL1A1) in human dermal fibroblasts (HDFs). It was further determined that let-7f-5p could target thrombospondin-1 (THBS1), thereby inhibiting the TGF-β2/Smad3 signaling pathway and exerting its biological effects. Additionally, let-7f-5p is regulated by Hsa_circ_0000437, which acts as a sponge molecule for let-7f-5p and consequently regulates the biological function of HDFs. Furthermore, our findings indicate that in vivo overexpression of let-7f-5p leads to a reduction in dermal thickness and COL1A1 expression, effectively inhibiting the progression of bleomycin (BLM)-induced skin fibrosis in mice. Hence, our research enhances the comprehension of the Hsa_circ_0000437/let-7f-5p/THBS1/TGF-β2/Smad3 regulatory network, highlighting the potential of let-7f-5p as a therapeutic approach for the treatment of skin fibrosis.

2023 Brazilian Society of Rheumatology guidelines for the treatment of systemic sclerosis

BACKGROUND

Systemic sclerosis (SSc) is a rare chronic autoimmune disease with heterogeneous manifestations. In the last decade, several clinical trials have been conducted to evaluate new treatment options for SSc. The purpose of this work is to update the recommendations of the Brazilian Society of Rheumatology in light of the new evidence available for the pharmacological management of SSc.

METHODS

A systematic review including randomized clinical trials (RCTs) for predefined questions that were elaborated according to the Patient/Population, Intervention, Comparison, and Outcomes (PICO) strategy was conducted. The rating of the available evidence was performed according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. To become a recommendation, at least 75% agreement of the voting panel was needed.

RESULTS

Six recommendations were elaborated regarding the pharmacological treatment of Raynaud's phenomenon, the treatment (healing) and prevention of digital ulcers, skin involvement, interstitial lung disease (ILD) and gastrointestinal involvement in SSc patients based on results available from RCTs. New drugs, such as rituximab, were included as therapeutic options for skin involvement, and rituximab, tocilizumab and nintedanib were included as therapeutic options for ILD. Recommendations for the pharmacological treatment of scleroderma renal crisis and musculoskeletal involvement were elaborated based on the expert opinion of the voting panel, as no placebo-controlled RCTs were found.

CONCLUSION

These guidelines updated and incorporated new treatment options for the management of SSc based on evidence from the literature and expert opinion regarding SSc, providing support for decision-making in clinical practice.

Advances in research on immunocyte iron metabolism, ferroptosis, and their regulatory roles in autoimmune and autoinflammatory diseases

Autoimmune diseases commonly affect various systems, but their etiology and pathogenesis remain unclear. Currently, increasing research has highlighted the role of ferroptosis in immune regulation, with immune cells being a crucial component of the body's immune system. This review provides an overview and discusses the relationship between ferroptosis, programmed cell death in immune cells, and autoimmune diseases. Additionally, it summarizes the role of various key targets of ferroptosis, such as GPX4 and TFR, in immune cell immune responses. Furthermore, the release of multiple molecules, including damage-associated molecular patterns (DAMPs), following cell death by ferroptosis, is examined, as these molecules further influence the differentiation and function of immune cells, thereby affecting the occurrence and progression of autoimmune diseases. Moreover, immune cells secrete immune factors or their metabolites, which also impact the occurrence of ferroptosis in target organs and tissues involved in autoimmune diseases. Iron chelators, chloroquine and its derivatives, antioxidants, chloroquine derivatives, and calreticulin have been demonstrated to be effective in animal studies for certain autoimmune diseases, exerting anti-inflammatory and immunomodulatory effects. Finally, a brief summary and future perspectives on the research of autoimmune diseases are provided, aiming to guide disease treatment strategies.

Pharmacokinetics of Fipaxalparant, a Small-Molecule Selective Negative Allosteric Modulator of Lysophosphatidic Acid Receptor 1, and the Effect of Food in Healthy Volunteers

Dysregulated lysophosphatidic acid receptor 1 (LPAR1) signaling is implicated in fibrotic diseases, including systemic sclerosis (SSc) and idiopathic pulmonary fibrosis (IPF). Fipaxalparant (HZN-825) is a small molecule acting as a negative allosteric modulator of LPAR1 and is in phase 2 clinical evaluations for treating diffuse cutaneous SSc and IPF. This open-label, phase 1 study examined the pharmacokinetics (PKs), food effect, and safety of fipaxalparant in healthy volunteers. Dose proportionality was evaluated for fipaxalparant single doses of 150, 300, and 450 mg under fasted conditions. Food effect was tested with a 450-mg single dose under fasted conditions or with a high-fat meal. Multiple-dose PKs for twice-daily dosing of either 300 or 450 mg with low- or high-fat meals was also assessed. Fipaxalparant was safe and well tolerated in healthy volunteers (n = 36) under all conditions. Fipaxalparant exposure increased in a less than dose-proportional manner from 150 to 450 mg. At 450 mg, a high-fat meal increased the maximum observed concentration and area under the curve by approximately 1.9- and 2.1-fold, respectively. These results, combined with prior preclinical and phase 2a data, informed dose selection of fipaxalparant 300 mg once and twice daily with a meal for phase 2b studies.

Lung Transplantation in Patients With Systemic Scleroderma-Description of the First Consecutive Cases in Poland: Case Series Report and a Short Literature Review

Pulmonary complications of systemic scleroderma (SSc), such as interstitial lung disease and pulmonary hypertension (PH), are responsible for up to 60% of deaths among patients. For many years, most centers considered SSc a contraindication to lung transplantation (LTx); however, recent publications show that appropriately selected SSc candidates for LTx give results comparable to patients with idiopathic PH or idiopathic pulmonary fibrosis. This paper presents the cases of a 60-year-old male patient (patient 1) and a 42-year-old female patient (patient 2) diagnosed with SSc in 2019 and 2013, respectively. In both patients, interstitial-fibrotic changes in the lungs leading to respiratory failure were confirmed by high-resolution computed tomography as well as pulmonary hypertension (WHO group 3), which was also diagnosed during right heart catheterization. In both cases, despite pharmacotherapy, pulmonary fibrosis progressed, leading to severe respiratory failure. The patients were referred for LTx qualification. LTx was possible to consider in patients due to the lack of significant changes in other internal organs. Double LTx was successfully performed in both patients (patient 1-July 19, 2022; patient 2-September 14, 2022). They were discharged from the hospital in good condition on the 22nd and 20th postoperative day, respectively. LTx is a last-chance therapy that saves lives among patients with extreme respiratory failure in the course of SSc. It prolongs and improves the quality of life. The selection of appropriate patients is key to the success of the procedure.

Safety of prolonged use of metoclopramide and domperidone as treatment for chronic gastrointestinal dysmotility disorders in patients with systemic sclerosis

Background

Metoclopramide and domperidone are prokinetic agents commonly used to treat gastrointestinal dysmotility disorders. This study aimed to evaluate the safety and associated side effects of prolonged-use metoclopramide and domperidone as treatment for chronic gastrointestinal dysmotility disorders in patients with systemic sclerosis (SSc).

Methods

A quantitative observational survey was conducted by interview questionnaire in rheumatology outpatients at a tertiary teaching hospital in Riyadh, Saudi Arabia. The study included all patients aged 25-80 years diagnosed with SSc. All patients were on metoclopramide or domperidone for the treatment of chronic gastrointestinal dysmotility symptoms over at least 12 weeks.

Results

Eighteen eligible patients were included. Most study participants were diagnosed with SSc complicated by interstitial lung disease (n = 13; 72.2 %). The most frequently reported side effect that occurred while taking prokinetic drugs was shortness of breath (n = 12; 66.7 %). None of the participants reported experiencing depression, galactorrhea, or syncope. CNS side effects were reported in 5.6 %. There were no differences in side effects based on the type and dosage of prokinetic drug used.

Conclusions

Use of metoclopramide and domperidone for the treatment of chronic gastrointestinal dysmotility in SSc patients for 12 weeks or longer was not associated with any troublesome side effects. Further studies with more participants are needed to confirm our findings.

F127-SE-tLAP thermosensitive hydrogel alleviates bleomycin-induced skin fibrosis via TGF-β/Smad pathway

BACKGROUND

Skin fibrosis affects the normal function of the skin. TGF-β1 is a key cytokine that affects organ fibrosis. The latency-associated peptide (LAP) is essential for TGF-β1 activation. We previously constructed and prepared truncated LAP (tLAP), and confirmed that tLAP inhibited liver fibrosis by affecting TGF-β1. SPACE peptide has both transdermal and transmembrane functions. SPACE promotes the delivery of macromolecules through the stratum corneum into the dermis. This study aimed to alleviate skin fibrosis through the delivery of tLAP by SPACE.

METHODS

The SPACE-tLAP (SE-tLAP) recombinant plasmid was constructed. SE-tLAP was purified by nickel affinity chromatography. The effects of SE-tLAP on the proliferation, migration, and expression of fibrosis-related and inflammatory factors were evaluated in TGF-β1-induced NIH-3T3 cells. F127-SE-tLAP hydrogel was constructed by using F127 as a carrier to load SE-tLAP polypeptide. The degradation, drug release, and biocompatibility of F127-SE-tLAP were evaluated. Bleomycin was used to induce skin fibrosis in mice. HE, Masson, and immunohistochemistry were used to observe the skin histological characteristics.

RESULTS

SE-tLAP inhibited the proliferation, migration, and expression of fibrosis-related and inflammatory factors in NIH-3T3 cells. F127-SE-tLAP significantly reduced ECM production, collagen deposition, and fibrotic pathological changes, thereby alleviating skin fibrosis.

CONCLUSION

F127-SE-tLAP could increase the transdermal delivery of LAP, reduce the production and deposition of ECM, inhibit the formation of dermal collagen fibers, and alleviate the progression of skin fibrosis. It may provide a new idea for the therapy of skin fibrosis.

Nintedanib downregulates the profibrotic M2 phenotype in cultured monocyte-derived macrophages obtained from systemic sclerosis patients affected by interstitial lung disease

BACKGROUND

Systemic sclerosis (SSc) is an autoimmune connective tissue disease characterized by vasculopathy and progressive fibrosis of skin and several internal organs, including lungs. Macrophages are the main cells involved in the immune-inflammatory damage of skin and lungs, and alternatively activated (M2) macrophages seem to have a profibrotic role through the release of profibrotic cytokines (IL10) and growth factors (TGFβ1). Nintedanib is a tyrosine kinase inhibitor targeting several fibrotic mediators and it is approved for the treatment of SSc-related interstitial lung disease (ILD). The study aimed to evaluate the effect of nintedanib in downregulating the profibrotic M2 phenotype in cultured monocyte-derived macrophages (MDMs) obtained from SSc-ILD patients.

METHODS

Fourteen SSc patients, fulfilling the 2013 ACR/EULAR criteria for SSc, 10 SSc patients affected by ILD (SSc-ILD pts), 4 SSc patients non affected by ILD (SSc pts no-ILD), and 5 voluntary healthy subjects (HSs), were recruited at the Division of Clinical Rheumatology-University of Genova, after obtaining Ethical Committee approval and patients' informed consent. Monocytes were isolated from peripheral blood, differentiated into MDMs, and then maintained in growth medium without any treatment (untreated cells), or treated with nintedanib (0.1 and 1µM) for 3, 16, and 24 h. Gene expression of macrophage scavenger receptors (CD204, CD163), mannose receptor-1 (CD206), Mer tyrosine kinase (MerTK), identifying M2 macrophages, together with TGFβ1 and IL10, were evaluated by quantitative real-time polymerase chain reaction. Protein synthesis was investigated by Western blotting and the level of active TGFβ1 was evaluated by ELISA. Statistical analysis was carried out using non-parametric Wilcoxon test.

RESULTS

Cultured untreated SSc-ILD MDMs showed a significant increased protein synthesis of CD206 (p < 0.05), CD204, and MerTK (p < 0.01), together with a significant upregulation of the gene expression of MerTK and TGFβ1 (p < 0.05; p < 0.01) compared to HS-MDMs. Moreover, the protein synthesis of CD206 and MerTK and the gene expression of TGFβ1 were significantly higher in cultured untreated MDMs from SSc-ILD pts compared to MDMs without ILD (p < 0.05; p < 0.01). In cultured SSc-ILD MDMs, nintedanib 0.1 and 1µM significantly downregulated the gene expression and protein synthesis of CD204, CD206, CD163 (p < 0.05), and MerTK (p < 0.01) compared to untreated cells after 24 h of treatment. Limited to MerTK and IL10, both nintedanib concentrations significantly downregulated their gene expression already after 16 h of treatment (p < 0.05). In cultured SSc-ILD MDMs, nintedanib 0.1 and 1µM significantly reduced the release of active TGFβ1 after 24 h of treatment (p < 0.05 vs. untreated cells).

CONCLUSIONS

In cultured MDMs from SSc-ILD pts, nintedanib seems to downregulate the profibrotic M2 phenotype through the significant reduction of gene expression and protein synthesis of M2 cell surface markers, together with the significant reduction of TGFβ1 release, and notably MerTK, a tyrosine kinase receptor involved in lung fibrosis.

Exosomal microRNA-Based therapies for skin diseases

Based on engineered cell/exosome technology and various skin-related animal models, exosomal microRNA (miRNA)-based therapies derived from natural exosomes have shown good therapeutic effects on nine skin diseases, including full-thickness skin defects, diabetic ulcers, skin burns, hypertrophic scars, psoriasis, systemic sclerosis, atopic dermatitis, skin aging, and hair loss. Comparative experimental research showed that the therapeutic effect of miRNA-overexpressing exosomes was better than that of their natural exosomes. Using a dual-luciferase reporter assay, the targets of all therapeutic miRNAs in skin cells have been screened and confirmed. For these nine types of skin diseases, a total of 11 animal models and 21 exosomal miRNA-based therapies have been developed. This review provides a detailed description of the animal models, miRNA therapies, disease evaluation indicators, and treatment results of exosomal miRNA therapies, with the aim of providing a reference and guidance for future clinical trials. There is currently no literature on the merits or drawbacks of miRNA therapies compared with standard treatments.

S100A4-neutralizing monoclonal antibody 6B12 counteracts the established experimental skin fibrosis induced by bleomycin

OBJECTIVES

Our previous studies have demonstrated that the Damage Associated Molecular Pattern (DAMP) protein, S100A4, is overexpressed in the involved skin and peripheral blood of patients with SSc. It is associated with skin and lung involvement, and disease activity. By contrast, lack of S100A4 prevented the development of experimental dermal fibrosis. Herein we aimed to evaluate the effect of murine anti-S100A4 mAb 6B12 in the treatment of preestablished experimental dermal fibrosis.

METHODS

The effects of 6B12 were assessed at therapeutic dosages in a modified bleomycin-induced dermal fibrosis mouse model by evaluating fibrotic (dermal thickness, proliferation of myofibroblasts, hydroxyproline content, phosphorylated Smad3-positive cell count) and inflammatory (leukocytes infiltrating the lesional skin, systemic levels of selected cytokines and chemokines) outcomes, and transcriptional profiling (RNA sequencing).

RESULTS

Treatment with 7.5 mg/kg 6B12 attenuated and might even reduce pre-existing dermal fibrosis induced by bleomycin as evidenced by reduction in dermal thickness, myofibroblast count and collagen content. These antifibrotic effects were mediated by the downregulation of TGF-β/Smad signalling and partially by reducing the number of leukocytes infiltrating the lesional skin and decrease in the systemic levels of IL-1α, eotaxin, CCL2 and CCL5. Moreover, transcriptional profiling demonstrated that 7.5 mg/kg 6B12 also modulated several profibrotic and proinflammatory processes relevant to the pathogenesis of SSc.

CONCLUSION

Targeting S100A4 by the 6B12 mAb demonstrated potent antifibrotic and anti-inflammatory effects on bleomycin-induced dermal fibrosis and provided further evidence for the vital role of S100A4 in the pathophysiology of SSc.

Recent Advances in Treatment of Systemic Sclerosis and Morphea

Systemic sclerosis (SSc) and morphea are autoimmune sclerosing diseases that cause significant morbidity, and in the case of SSc, mortality. The pathogenesis of both SSc and morphea share vascular dysfunction, auto-reactive T cells and Th2-associated cytokines, such as interleukin 4, and overproduction of transforming growth factor beta (TGFβ). TGFβ stimulates fibroblast collagen and extra-cellular matrix production. Although morphea and SSc have similar pathogenic pathways and histological findings, they are distinct diseases. Recent advances in treatment of morphea, skin sclerosis in SSc, and interstitial lung disease in SSc are focused on targeting known pathogenic pathways.

A Multidisciplinary Approach as a Goal for the Management of Complications in Systemic Scleroderma: A Literature Review and Case Scenario

Systemic sclerosis (also known as scleroderma) is a chronic fibrosing autoimmune disease with both skin and multisystem organ involvement. Scleroderma has the highest mortality among all rheumatic diseases. The pathophysiology mechanism of systemic sclerosis is a progressive self-amplifying process, which involves widespread microvascular damage, followed by a dysregulation of innate and adaptive immunity and inflammation and diffuse fibrosis of the skin and visceral organs. Fibrosis of internal organs is a hint for systemic sclerosis, moreover associated with interstitial lung disease (SSc-ILD) is a complex process. In order to correlate scientific data from the literature with clinical experience, we present the case of a 56-year-old woman who was diagnosed with systemic sclerosis 16 years ago. The association of numerous comorbidities characterized by a considerable level of seriousness characterizes this case: the highly extensive systemic damage, the cardiovascular impact of the illness, and the existence of severe pulmonary arterial hypertension. The systemic and clinical manifestations, respiratory functional tests, radiological features, and specific therapy are discussed.

Distinct molecular subtypes of systemic sclerosis and gene signature with diagnostic capability

Background

As Systemic Sclerosis (SSc) is a connective tissue ailment that impacts various bodily systems. The study aims to clarify the molecular subtypes of SSc, with the ultimate objective of establishing a diagnostic model that can inform clinical treatment decisions.

Methods

Five microarray datasets of SSc were retrieved from the GEO database. To eliminate batch effects, the combat algorithm was applied. Immune cell infiltration was evaluated using the xCell algorithm. The ConsensusClusterPlus algorithm was utilized to identify SSc subtypes. Limma was used to determine differential expression genes (DEGs). GSEA was used to determine pathway enrichment. A support vector machine (SVM), Random Forest(RF), Boruta and LASSO algorithm have been used to select the feature gene. Diagnostic models were developed using SVM, RF, and Logistic Regression (LR). A ROC curve was used to evaluate the performance of the model. The compound-gene relationship was obtained from the Comparative Toxicogenomics Database (CTD).

Results

The identification of three immune subtypes in SSc samples was based on the expression profiles of immune cells. The utilization of 19 key intersectional DEGs among subtypes facilitated the classification of SSc patients into three robust subtypes (gene_ClusterA-C). Gene_ClusterA exhibited significant enrichment of B cells, while gene_ClusterC showed significant enrichment of monocytes. Moderate activation of various immune cells was observed in gene_ClusterB. We identified 8 feature genes. The SVM model demonstrating superior diagnostic performance. Furthermore, correlation analysis revealed a robust association between the feature genes and immune cells. Eight pertinent compounds, namely methotrexate, resveratrol, paclitaxel, trichloroethylene, formaldehyde, silicon dioxide, benzene, and tetrachloroethylene, were identified from the CTD.

Conclusion

The present study has effectively devised an innovative molecular subtyping methodology for patients with SSc and a diagnostic model based on machine learning to aid in clinical treatment. The study has identified potential molecular targets for therapy, thereby offering novel perspectives for the treatment and investigation of SSc.

Further insight into systemic sclerosis from the vasculopathy perspective

Systemic sclerosis (SSc) is an autoimmune disease characterized by immune dysfunction, vascular system dysfunction, and tissue fibrosis. Vascular injury, vascular remodeling, and endothelial dysfunction are the hallmark pathological changes of the disease. In the early stages of SSc development, endothelial cell injury and apoptosis can lead to vascular and perivascular inflammation, oxidative stress, and tissue hypoxia, which can cause clinical manifestations in various organs from the skin to the parenchymal organs. Early diagnosis and rational treatment can improve patient survival and quality of life. Ancillary examinations such as nailfold capillaroscopy as well as optical coherence tomography can help early detect vascular injury in SSc patients. Studies targeting the mechanisms of vascular lesions will provide new perspectives for treatment of SSc.

Reference value for the 6-min walking distance in women with systemic sclerosis considering the impact of muscle strength

BACKGROUND

Early triage, the search for new therapies, and closer monitoring of patients with systemic sclerosis before their lung function irreversibly deteriorates are urgent concerns. Because it is an independent predictor of systemic sclerosis-related mortality, the 6-min walk test is a potentially useful tool to evaluate outcomes, along with pulmonary function and computed tomography. This study aimed to establish a reference value for the 6-min walking distance in women with diffuse cutaneous systemic sclerosis-associated interstitial lung disease that takes into account the effects of muscle and lung function.

METHODS

This was a cross-sectional study in which 69 women with systemic sclerosis underwent the 6-min walk test, Health Assessment Questionnaire-Disability Index, pulmonary function, handgrip strength test, and quadriceps strength test.

FINDINGS

The mean 6-min walking distance was 447 ± 78 m, and 43.5% of the participants did not reach 80% of their predicted value. 6-min walking distance correlated positively with quadriceps strength (r = 0.418, P = 0.0004), forced vital capacity (r = 0.306, P = 0.011), pulmonary diffusion (r = 0.360, P = 0.002), maximum inspiratory pressure (r = 0.268, P = 0.029), and maximum expiratory pressure (r = 0.288, P = 0.019) and negatively with age (r = -0.378, P = 0.001), body mass index (r = -0.248, P = 0.039), and Health Assessment Questionnaire-Disability Index (r = -0.438, P = 0.0001). In the multiple linear regression analysis, quadriceps strength, body mass index, pulmonary diffusion, age, and maximum expiratory pressure explained 72% of the 6-min walking distance variability.

INTERPRETATION

Muscle function and, to a lesser extent, lung function are key contributors in determining the reference value for the 6-min walking distance in women with diffuse cutaneous systemic sclerosis-associated interstitial lung disease.

Biomarkers of fibrosis, inflammation, and extracellular matrix in the phase 3 trial of tocilizumab in systemic sclerosis

Drug development for systemic sclerosis (SSc) benefits from understanding the relationship between disease and circulating biomarkers to enable activities such as patient stratification and evaluation of therapeutic response. We measured biomarkers in serum from SSc patients from a phase 3 trial of tocilizumab (focuSSced) and compared baseline levels with healthy controls (HCs). Several baseline biomarkers appeared elevated in SSc patients compared to HCs, suggesting activation of epithelial damage, inflammation, fibrosis, and extracellular matrix (ECM) remodeling. Baseline correlations among both periostin/COMP and ECM biomarker subsets implicated their participation in fibroblast activation. Tocilizumab treatment modulated serum biomarkers of macrophage activation, inflammation, and ECM turnover, including collagen formation and degradation neoepitopes. Baseline CRP, periostin, and SP-D showed prognostic trends for worsening lung function, and IL-6, COMP, periostin, and Pro-C3 showed prognostic trends for worsening skin thickness. These prognostic results warrant confirmation in additional patient cohorts to verify their utility.

Scleromyositis: A Novel Entity Beyond Systemic Sclerosis and Autoimmune Myositis

Scleromyositis is a new clinical entity, which not only has clinical and histopathological components of systemic sclerosis and inflammatory myopathy but is also characterized by presenting unique characteristics, which may not be in the previously mentioned diseases. Up until now, there are no specific classification criteria proposed by the American College of Rheumatology or the European League Against Rheumatism (ACR/EULAR). This paper presents a case report of a female patient in her 60s who was admitted to our institution due to muscle weakness in her legs and dysphagia. Within her diagnosis approach, clinical characteristics compatible with autoimmune myopathy were found; however, she presented with anti-PM/Scl75 antibody-positive results. In this paper, we emphasized the clinical characteristics and forms of presentation of scleromyositis, additionally discussing the available treatment for this entity.

The Role of CCL24 in Systemic Sclerosis

Systemic sclerosis (SSc) is a chronic immune-mediated disease characterized by microangiopathy, immune dysregulation, and progressive fibrosis of the skin and internal organs. Though not fully understood, the pathogenesis of SSc is dominated by microvascular injury, endothelial dysregulation, and immune response that are thought to be associated with fibroblast activation and related fibrogenesis. Among the main clinical subsets, diffuse SSc (dSSc) is a progressive form with rapid and disseminated skin thickening accompanied by internal organ fibrosis and dysfunction. Despite recent advances and multiple randomized clinical trials in early dSSc patients, an effective disease-modifying treatment for progressive skin fibrosis is still missing, and there is a crucial need to identify new targets for therapeutic intervention. Eotaxin-2 (CCL24) is a chemokine secreted by immune cells and epithelial cells, which promotes trafficking of immune cells and activation of pro-fibrotic cells through CCR3 receptor binding. Higher levels of CCL24 and CCR3 were found in the skin and sera of patients with SSc compared with healthy controls; elevated levels of CCL24 and CCR3 were associated with fibrosis and predictive of greater lung function deterioration. Growing evidence supports the potency of a CCL24-blocking antibody as an anti-inflammatory and anti-fibrotic modulating agent in multiple preclinical models that involve liver, skin, and lung inflammation and fibrosis. This review highlights the role of CCL24 in orchestrating immune, vascular, and fibrotic pathways, and the potential of CCL24 inhibition as a novel treatment for SSc.

Advancements in adipose-derived stem cell therapy for skin fibrosis

Pathological scarring and scleroderma, which are the most common conditions of skin fibrosis, pathologically manifest as fibroblast proliferation and extracellular matrix (ECM) hyperplasia. Fibroblast proliferation and ECM hyperplasia lead to fibrotic tissue remodeling, causing an exaggerated and prolonged wound-healing response. The pathogenesis of these diseases has not been fully clarified and is unfortunately accompanied by exceptionally high medical needs and poor treatment effects. Currently, a promising and relatively low-cost treatment has emerged-adipose-derived stem cell (ASC) therapy as a branch of stem cell therapy, including ASCs and their derivatives-purified ASC, stromal vascular fraction, ASC-conditioned medium, ASC exosomes, etc., which are rich in sources and easy to obtain. ASCs have been widely used in therapeutic settings for patients, primarily for the defection of soft tissues, such as breast enhancement and facial contouring. In the field of skin regeneration, ASC therapy has become a hot research topic because it is beneficial for reversing skin fibrosis. The ability of ASCs to control profibrotic factors as well as anti-inflammatory and immunomodulatory actions will be discussed in this review, as well as their new applications in the treatment of skin fibrosis. Although the long-term effect of ASC therapy is still unclear, ASCs have emerged as one of the most promising systemic antifibrotic therapies under development.

Umbilical-Cord-Derived Mesenchymal Stromal Cells Modulate 26 Out of 41 T Cell Subsets from Systemic Sclerosis Patients

Systemic sclerosis (SSc) is an immune-mediated disease wherein T cells are particularly implicated, presenting a poor prognosis and limited therapeutic options. Thus, mesenchymal-stem/stromal-cell (MSC)-based therapies can be of great benefit to SSc patients given their immunomodulatory, anti-fibrotic, and pro-angiogenic potential, which is associated with low toxicity. In this study, peripheral blood mononuclear cells from healthy individuals (HC, n = 6) and SSc patients (n = 9) were co-cultured with MSCs in order to assess how MSCs affected the activation and polarization of 58 different T cell subsets, including Th1, Th17, and Treg. It was found that MSCs downregulated the activation of 26 out of the 41 T cell subsets identified within CD4⁺, CD8⁺, CD4⁺CD8⁺, CD4^-CD8^-, and γδ T cells in SSc patients (HC: 29/42) and affected the polarization of 13 out of 58 T cell subsets in SSc patients (HC: 22/64). Interestingly, SSc patients displayed some T cell subsets with an increased activation status and MSCs were able to downregulate all of them. This study provides a wide-ranging perspective of how MSCs affect T cells, including minor subsets. The ability to inhibit the activation and modulate the polarization of several T cell subsets, including those implicated in SSc's pathogenesis, further supports the potential of MSC-based therapies to regulate T cells in a disease whose onset/development may be due to immune system's malfunction.

State-of-the-art evidence in the treatment of systemic sclerosis

Systemic sclerosis (SSc) is a rare autoimmune connective tissue disease with multi-organ involvement, fibrosis and vasculopathy. Treatment in SSc, including early diffuse cutaneous SSc (dcSSc) and the use of organ-specific therapies, has improved, as evident from randomized clinical trials. Treatments for early dcSSc include immunosuppressive agents such as mycophenolate mofetil, methotrexate, cyclophosphamide, rituximab and tocilizumab. Patients with rapidly progressive early dcSSc might be eligible for autologous haematopoietic stem cell transplantation, which can improve survival. Morbidity from interstitial lung disease and pulmonary arterial hypertension is improving with the use of proven therapies. Mycophenolate mofetil has surpassed cyclophosphamide as the initial treatment for SSc-interstitial lung disease. Nintedanib and possibly perfinidone can be considered in SSc pulmonary fibrosis. Pulmonary arterial hypertension is frequently treated with initial combination therapy (for example, with phosphodiesterase 5 inhibitors and endothelin receptor antagonists) and, if necessary, the addition of a prostacyclin analogue. Raynaud phenomenon and digital ulcers are treated with dihydropyridine calcium channel blockers (especially nifedipine), then phosphodiesterase 5 inhibitors or intravenous iloprost. Bosentan can reduce the development of new digital ulcers. Trial data for other manifestations are mostly lacking. Research is needed to develop targeted and highly effective treatments, best practices for organ-specific screening and early intervention, and sensitive outcome measurements.

Step forward in early recognition of systemic sclerosis: data from the Leiden CCISS cohort

BACKGROUND

Since 2009, Dutch patients with a confirmed diagnosis/suspicion of systemic sclerosis (SSc) can be referred to the Leiden Combined Care in Systemic Sclerosis (CCISS) cohort. This study evaluated whether early recognition of SSc has improved over time and whether disease characteristics and survival has changed over time.

METHODS

643 SSc patients fulfilling American College of Rheumatology/European Alliance of Associations for Rheumatology 2013 SSc criteria were included and categorised into three groups based on cohort-entry year: (1) 2010-2013 (n=229 (36%)), (2) 2014-2017 (n=207 (32%)) and (3) 2018-2021 (n=207 (32%)). Variables including disease duration, interstitial lung disease (ILD), digital ulcers (DU), diffuse cutaneous SSc (dcSSc), antitopoisomerase (ATA) and anticentromere (ACA) antibodies, and survival from disease onset were compared between cohort-entry groups, including analyses stratified for sex and autoantibodies.

RESULTS

Over time, duration between onset of disease symptoms and cohort entry decreased in males and females, but was always longer in females than in males.The proportion of patients presenting with DU decreased, especially in ACA+SSc patients. Almost no ACA+ patients presented with ILD, while in ATA+ patients this proportion was 25% in 2010-2013 and decreased to 19% in 2018-2021. A reduction in patients presenting with clinically meaningful ILD and dcSSc was observed.Overall 8-year survival for males was 59% (95% CI 40% to 73%) and for females 89% (95% CI 82% to 93%). Eight-year survival showed a trend for improvement over time, and was always worse in males.

CONCLUSION

We observed a decrease in disease duration in Leiden CCISS cohort at cohort entry, possibly indicating more timely diagnosis of SSc. This could provide opportunities for early interventions. While symptom duration at presentation is longer in females, mortality is consistently higher in males, underlining the urge for sex-specific treatment and follow-up.

Scleromyositis: A distinct novel entity within the systemic sclerosis and autoimmune myositis spectrum. Implications for care and pathogenesis

Systemic sclerosis and autoimmune myositis are both associated with decreased quality of life and increased mortality. Their prognosis and management largely depend on the disease subgroups. Indeed, systemic sclerosis is a heterogeneous disease, the two predominant forms of the disease being limited and diffuse scleroderma. Autoimmune myositis is also a heterogeneous group of myopathies that classically encompass necrotizing myopathy, antisynthetase syndrome, dermatomyositis and inclusion body myositis. Recent data revealed that an additional disease subset, denominated "scleromyositis", should be recognized within both the systemic sclerosis and the autoimmune myositis spectrum. We performed an in-depth review of the literature with the aim of better delineating scleromyositis. Our review highlights that this concept is supported by recent clinical, serological and histopathological findings that have important implications for patient management and understanding of the disease pathophysiology. As compared with other subsets of systemic sclerosis and autoimmune myositis, scleromyositis patients can present with a characteristic pattern of muscle involvement (i.e. distribution of muscle weakness) along with multisystemic involvement, and some of these extra-muscular complications are associated with poor prognosis. Several autoantibodies have been specifically associated with scleromyositis, but they are not currently integrated in diagnostic and classification criteria for systemic sclerosis and autoimmune myositis. Finally, striking vasculopathic lesions at muscle biopsy have been shown to be hallmarks of scleromyositis, providing a strong anatomopathological substratum for the concept of scleromyositis. These findings bring new insights into the pathogenesis of scleromyositis and help to diagnose this condition, in patients with subtle SSc features and/or no autoantibodies (i.e. "seronegative" scleromyositis). No guidelines are available for the management of these patients, but recent data are showing the way towards a new therapeutic approach dedicated to these patients.

Human Regulatory T Cells: Understanding the Role of Tregs in Select Autoimmune Skin Diseases and Post-Transplant Nonmelanoma Skin Cancers

Regulatory T cells (Tregs) play an important role in maintaining immune tolerance and homeostasis by modulating how the immune system is activated. Several studies have documented the critical role of Tregs in suppressing the functions of effector T cells and antigen-presenting cells. Under certain conditions, Tregs can lose their suppressive capability, leading to a compromised immune system. For example, mutations in the Treg transcription factor, Forkhead box P3 (FOXP3), can drive the development of autoimmune diseases in multiple organs within the body. Furthermore, mutations leading to a reduction in the numbers of Tregs or a change in their function facilitate autoimmunity, whereas an overabundance can inhibit anti-tumor and anti-pathogen immunity. This review discusses the characteristics of Tregs and their mechanism of action in select autoimmune skin diseases, transplantation, and skin cancer. We also examine the potential of Tregs-based cellular therapies in autoimmunity.

The Microbiome in Systemic Sclerosis: Pathophysiology and Therapeutic Potential

Systemic sclerosis (SSc), also known as scleroderma, is an autoimmune disease with unknown etiology characterized by multi-organ fibrosis. Despite substantial investigation on SSc-related cellular and molecular mechanisms, effective therapies are still lacking. The skin, lungs, and gut are the most affected organs in SSc, which act as physical barriers and constantly communicate with colonized microbiota. Recent reports have documented a unique microbiome signature, which may be the pathogenic trigger or driver of SSc. Since gut microbiota influences the efficacy and toxicity of oral drugs, evaluating drug-microbiota interactions has become an area of interest in disease treatment. The existing evidence highlights the potential of the microbial challenge as a novel therapeutic option in SSc. In this review, we have summarized the current knowledge about molecular mechanisms of SSc and highlighted the underlying role of the microbiome in SSc pathogenesis. We have also discussed the latest therapeutic interventions using microbiomes in SSc, including drug-microbiota interactions and animal disease models. This review aims to elucidate the pathophysiological connection and therapeutic potential of the microbiome in SSc. Insights into the microbiome will significantly improve our understanding of etiopathogenesis and developing therapeutics for SSc.