Systemic sclerosis

Quantification of coronary artery calcification in systemic sclerosis using visual ordinal and deep learning scoring: Association with systemic sclerosis clinical features

OBJECTIVE

To investigate the association between systemic sclerosis (SSc) clinical features and the extent and progression of coronary artery calcifications.

METHODS

We conducted a single-center retrospective cohort study of patients with SSc. In our primary aim, we investigated the association between SSc clinical features and the annual progression of coronary artery calcium (CAC) scores quantified using the visual ordinal scoring method. In our secondary aim, we utilized DeepCAC, a deep learning-based method, to quantify coronary artery calcifications ("deep learning CAC score"), and explored its association with SSc clinical features.

RESULTS

Eighty-six SSc patients were included in the primary aim and 171 in the secondary aim. SSc disease duration was inversely associated with annual ordinal CAC score progression in the demographics-adjusted model (coefficient = -0.004, 95 % CI -0.006 to -0.001, p-value = 0.01) and the demographics- and cardiovascular (CV) risk factor-adjusted model (coefficient = -0.004, 95 % CI -0.008 to -0.0004, p-value = 0.03). The presence of "fingertip ischemic ulcers or digital pitting scars" (demographics-adjusted model: coefficient = 1.07, 95 % CI 0.29 to 1.85, p < 0.01; demographics- and CV risk factor-adjusted model: coefficient = 1.39, 95 % CI 0.43 to 2.34, p < 0.01) and Group 1 pulmonary hypertension (demographics-adjusted model: coefficient = 1.34, 95 % CI 0.34 to 2.35, p < 0.01; demographics- and CV risk factor-adjusted model: coefficient = 1.52, 95 % CI 0.38 to 2.65, p < 0.01) were both associated with the deep learning CAC score.

CONCLUSION

Our results suggest that the progression of coronary artery calcification accelerates early during the SSc disease course and that severe microvasculopathy may be a risk factor for atherosclerotic CVD.

Generation of human induced pluripotent stem cell lines (iPSC) from adipose-derived mesenchymal stromal cells from two patients with systemic sclerosis

Systemic sclerosis (SSc) is a rare and complex connective tissue disease associated with high morbidity and mortality. SSc is characterized by ischemic vasculopathy, cutaneous and visceral fibrosis and a dysimmune state (Denton and Khanna, 2017; Volkmann et al., 2023; Barnes and Mayes, 2012). We have derived induced pluripotent stem cell (iPSC) lines from two SSc patients aged 38 and 67 years with severe vascular phenotype. These iPSC lines expressed pluripotent markers, exhibited normal and stable genome, and differentiated into trilineage embryonic layers in teratoma formation assays. These SSc-specific iPSC lines can be differentiated into endothelial cells, providing a valuable model to elucidate vascular dysfunction and develop personalized therapeutic approaches.

The predictive value of anti-IFI16 antibodies for the development or persistence of digital ulcers in systemic sclerosis

To evaluate the association of anti-IFI16 antibodies with peripheral vasculopathy and the predictive value of anti-IFI16 antibodies for the development or persistence of digital ulcers (DPDU) in SSc. A total of 42 SSc patients and 42 age- and sex-matched healthy controls were enrolled. Anti-IFI16 antibodies were examined by ELISA. Nailfold videocapillaroscopy (NVC) and power Doppler ultrasound (PDUS) were used to assess the micro- and macro-vascular involvement in SSc. All patients were followed up for 6 months to evaluate DPDU. Potential risk factors for DPDU were analyzed by a Firth's penalized logistic regression model. Of the 42 SSc patients enrolled, 19.05% patients were positive for anti-IFI16 antibodies, compared to a significantly low positivity rate of 4.76% in healthy controls (p < 0.001). SSc patients who were positive for anti-IFI16 antibodies manifested higher ulnar artery resistance index than anti-IFI16 negative patients (p = 0.018). Within a 6-month follow-up, 14 (33.3%) patients suffered from DPDU, and the prevalence of anti-IFI16 antibodies in patients with DPDU was 42.9%, remarkably higher than 7.1% in those without DPDU (p = 0.012). Additionally, patients with DPDU were more likely to have digital ulcers (DUs) at enrollment and manifest lower finger pulp blood flow, lower ulnar artery (UA) flow velocity, lower UA resistance index, and higher UA resistance index at baseline in comparison to patients without DPDU. Multivariate analysis further identified DUs at enrollment (OR 5.81; 95% CI 1.09-30.86; p = 0.046) and the positivity of anti-IFI16 antibody (OR 8.64; 95% CI 1.05-70.87; p = 0.045) as independent risk factors for DPDU. Presence of anti-IFI16 antibody is associated with higher UA resistance index in SSc. Multivariate analysis further identified anti-IFI16 antibody as a predictive marker for DPDU in SSc. Key Points • SSc patients who were positive for anti-IFI16 antibodies manifested higher ulnar artery resistance at baseline. • The prevalence of anti-IFI16 antibodies in patients with DPDU during the 6-month follow-up was remarkably higher than those without DPDU. • Multivariate analysis identified DUs at enrollment and anti-IFI16 antibody positivity as independent risk factors for DPDU. • Anti-IFI16 antibody is associated with peripheral vasculopathy in SSc. Multivariate analysis further identified anti-IFI16 as a predictive biomarker for the development of DUs.

Comparison of Three Physician Global Assessment Instruments in Systemic Sclerosis

OBJECTIVE

Physician global assessments (PhyGAs) are variably applied in systemic sclerosis (SSc) clinical trials. The comparability of different PhyGA results is unknown. We sought to assess the comparability of results from three different PhyGA instruments simultaneously applied in the Australian Scleroderma Cohort Study (ASCS).

METHODS

Using data from 1,965 ASCS participants, we assessed the correlation between results of three PhyGA assessments: (1) overall health, (2) activity, and (3) damage. We evaluated the concordance of change in each PhyGA between study visits. Ordered logistic regression analysis was used to evaluate the clinical associations of each PhyGA.

RESULTS

The absolute scores of each PhyGA were strongly correlated at individual study visits. Concordant changes of the PhyGA scores occurred between 50% of study visits. Only patient-reported breathlessness was associated with all three PhyGA scores (overall health: odds ratio [OR] 1.67, P < 0.01; activity: OR 1.44, P < 0.01; damage: OR 1.32, P < 0.01). Changes in physician-assessed activity scores were also associated with patient-reported worsening skin disease (OR 1.25, P = 0.03) and fecal incontinence (OR 1.23, P = 0.01), whereas damage scores were associated with respiratory disease (pulmonary arterial hypertension: OR 1.25, P = 0.03; chronic obstructive pulmonary disease: OR 1.37, P = 0.04), as well as skin scores (OR 1.02, P < 0.01) and fecal incontinence (OR 1.21, P = 0.02).

CONCLUSION

PhyGAs of overall health, activity, and damage are each associated with different SSc features, and changes in different PhyGA scores are discordant 50% of the time. Our findings suggest results of variably worded PhyGAs are not directly interchangeable and support the development of a standardized PhyGA.

Topical Application of Nitrate Ameliorates Skin Fibrosis by Regulating ST2+CD4+ T Cells in Systemic Sclerosis Mouse Model

Systemic sclerosis (SSc) is characterized by intractable multiorgan fibrosis caused by vascular and immune dysfunction. Currently, effective therapeutic options for patients with SSc are limited. Nitrate, an abundant nutrient in the diet, has been demonstrated to be preventative and therapeutic for several diseases. To determine whether nitrate can slow or reverse SSc progression, topical application of nitrate delivered by dissolving microneedles was used to treat a bleomycin-induced dermal fibrosis mouse model. In this study, nitrate considerably attenuated dermal thickness, stiffness, and collagen deposition. Bulk RNA sequencing of skin revealed that Cd4 was a key hub gene in SSc nitrate therapy. In addition, bleomycin-induced cytokines and chemokines were inhibited by nitrate, and CD4+ T cells infiltration markedly declined. Il4, Il6, Il13, and Tgfb expressions in CD4+ T cells isolated from skin biopsies also significantly decreased. Mechanistically, Il1rl1, a type 2 immune response inducer, was markedly repressed in isolated CD4+ T cells and dermal tissues after nitrate treatment. Remarkably, compared with wild-type mice, mice lacking Il1rl1 showed impaired transcriptional profiles after intradermal bleomycin injection. Adoptive transfer of ST2+CD4+ T cells promoted bleomycin-induced Rag2-/- mice dermal fibrosis. Collectively, these findings demonstrate that nitrate targeting ST2+CD4+ T cells is an effective therapeutic option for SSc.

Preliminary nomogram model for predicting irreversible organ damage of patients with systemic sclerosis

OBJECTIVE

To investigate predictive factors for irreversible organ damage in systemic sclerosis (SSc) and establish a nomogram model.

METHODS

This retrospective study included patients with SSc who were treated at our hospital between March 2013 and March 2023. Irreversible organ damage included heart failure, respiratory failure, renal failure, and gangrene of the hands and feet. Cox and LASSO regression analyses were performed to determine the predictive factors. Based on the results, a nomogram model was developed. The model was evaluated using the C-indices, calibration plots and DCA.

RESULTS

A total of 361 patients with systemic sclerosis were randomly divided into the development (n = 181) and validation (n = 180) groups. Multivariate Cox regression analysis showed that age ≥65 years, weight loss, digital ulcers, mRSS ≥16, elevated creatinine, elevated myoglobin, elevated C-reactive protein, renal involvement and cardiac involvement were independent risk factors. Based on the LASSO analysis, a nomogram model of irreversible organ damage was established. The C-indices of the development group at 24, 60 and 96 m were 96.7, 84.5 and 85.7, whereas those of the validation group at 24, 60 and 96 m were 86.6, 79.1 and 78.5, respectively. The results of the DCA showed that the nomogram can be used as a valuable tool to predict irreversible organ damage in patients with SSc.

CONCLUSION

We included commonly used clinical indicators. According to the nomogram, the probability of irreversible organ damage can be calculated and high-risk patients can be identified.

Well-Being Therapy in systemic sclerosis outpatients: a randomized controlled trial

OBJECTIVES

Systemic sclerosis (SSc) patients have psychological distress and poor well-being and need a tailored treatment. Psychological interventions, rarely tested for efficacy, showed poor benefits. The present randomized controlled trial tested the efficacy of Well-Being Therapy (WBT) in SSc patients.

METHODS

Thirty-two outpatients were randomized (1:1) to WBT (n = 16) or Treatment As Usual (i.e. routine medical check-ups) (TAU) (n = 16). Primary outcome was well-being. Secondary outcomes included functional ability related to SSc, psychological distress, mental pain, suffering. All participants were assessed at baseline (T0). The WBT group was assessed after two months (end of WBT session 4) (T1), after four months (end of WBT session 8) (T2), after seven months (3-month follow-up) (T3) and after 10 months (6-month follow-up) (T4). The TAU group was assessed two (T1), four (T2), seven (T3) and ten (T4) months after baseline.

RESULTS

WBT produced a significant improvement in subjective well-being (P ≤ 0.001), personal growth (P = 0.006), self-acceptance (P = 0.003) compared with TAU, maintained at T3 as what concerns subjective well-being (P = 0.012). WBT produced a greater decrease in psychological distress (P = 0.010), mental pain (P = 0.010), suffering (P ≤ 0.001) compared with TAU, maintained at T4 as what concerns suffering (P ≤ 0.001). Participants reported high satisfaction with WBT.

CONCLUSION

The study provides preliminary evidence on the benefits of WBT as short-term approach for in- and out-patient SSc healthcare paths. Studies with larger samples are needed to have the evidence for recommending WBT to SSc patients.

Accrual of organ damage and one-year mortality in systemic sclerosis: A prospective observational study

OBJECTIVE

To determine cumulative organ damage in patients with systemic sclerosis (SSc) according to the Scleroderma Clinical Trials Consortium Damage Index (SCTC-DI), assess 1-year mortality risk, and identify associated factors.

METHODS

A prospective, single-center study was conducted in a cohort of patients with SSc. A cross-sectional study and a 12-month longitudinal follow-up were carried out. The main outcomes were SCTC-DI and all-cause mortality at 12 months. Other variables included clinical-laboratory data, modified Rodnan Skin Score (mRSS), EuroQoL 5-D (EQ-5D), and Steinbrocker functional status. Multivariate models were used to study factors associated with SCTC-DI and mortality.

RESULTS

The study population comprised 75 patients (97.3% females) with a mean age of 59.6 years. The median (IQR) of the SCTC-DI was 4(6), and only 4 (5.3%) patients had severe SCTC-DI (≥13). The factors associated with SCTC-DI were disease duration (β=0.276), mRSS (β=0.287), C-reactive protein (CRP) concentration (β=0.311), and EQ-5D (β= -0.207). After 1 year of follow-up, 4 patients had died. The factors associated with mortality at 12 months (OR [95% CI]) were baseline SCTC-DI ≥13 (44.5 [1.6-1237.9]; p = 0.025) and visual analog scale (VAS) of the EQ-5D (0.9 [0.8-0.9]; p = 0.018).

CONCLUSIONS

The SCTC DI can prove useful in clinical practice for assessing disease progression and short-term mortality risk. Cumulative damage was associated with disease duration, mRSS, CRP concentration, and a decline in EQ-5D, while the risk of death at 12 months was primarily associated with high SCTC-DI and low EQ-5D VAS. New studies are needed to improve assessment tools in patients with SSc.

The pathogenesis, diagnostic utility and clinical relevance of cutaneous telangiectasia in systemic sclerosis

Cutaneous telangiectasia (Tel) are visible permanently dilated postcapillary dermal venules and are one of the most common disease-specific manifestations of systemic sclerosis (SSc). Telangiectasia have long been recognised for their utility in the diagnosis and classification of SSc, but the clinical and prognostic relevance of these aberrant cutaneous vascular manifestations has been somewhat neglected by clinicians. Similarly, the impact of SSc-Tel on body image dissatisfaction and social discomfort has been under-appreciated. The paucity of evidence-based approaches to management has limited access to potential effective treatments for SSc-Tel. The present review examines the pathogenesis, diagnostic value, impact and clinical relevance of telangiectasia in SSc. We highlight the potentially overlooked prognostic value and clinical utility of SSc-Tel, as part of a broader appraisal of areas of unmet research need.

Inadequate sleep hygiene as a key factor in poor sleep quality in systemic sclerosis: an observational, cross-sectional study

This study aims to investigate the relationship between sleep hygiene and sleep quality in patients with systemic sclerosis (SSc) and to compare the sleep hygiene and sleep quality outcomes across three distinct groups: SSc patients, rheumatoid arthritis (RA) patients, and healthy controls (HC). This study employed an observational, cross-sectional, and parallel group design. SSc-related and RA-related variables, depression and anxiety were assessed. Physical function and quality of life, pain and fatigue of SSc patients were also evaluated. Sleep quality using the Pittsburg Sleep Quality Index (PSQI) and sleep hygiene using the Sleep Hygiene Index (SHI) were evaluated for all participants. Linear regression analysis was performed to show the relationship between the SHI scores and the other variables. Total PSQI and SHI scores were found to be significantly higher in SSc patients than in RA patients and HC. Fatigue, smoking, all SF-36 domains, depression and anxiety scores were associated with SHI scores in SSc patients. In the univariate logistic regression analysis, SSc patients exhibited 4.50 times higher odds (95% CI 2.165-9.353, p < 0.001) of experiencing poor sleep than RA patients and HC. In SSc patients, for every incremental increase in SHI score, the odds of poor sleep quality were 1.15 times higher (95% CI 1.093-1.220, p < 0.001). Sleep hygiene and sleep quality exhibit a more pronounced deterioration in SSc patients. Inadequate sleep hygiene is associated with compromised sleep quality in SSc. Therefore, improving sleep hygiene practices may be a key strategy to enhance the overall sleep quality in this population.

The B-cells paradigm in systemic sclerosis: an update on pathophysiology and B-cell-targeted therapies

Systemic sclerosis (SSc) is considered a rare autoimmune disease in which there are alterations of both the innate and adaptive immune response resulting in the production of autoantibodies. Abnormalities of the immune system compromise the normal function of blood vessels leading to a vasculopathy manifested by Raynaud's phenomenon, an early sign of SSc . As a consequence of this reactive picture, the disease can evolve leading to tissue fibrosis. Several SSc-specific autoantibodies are currently known and are associated with specific clinical manifestations and prognosis. Although the pathogenetic role of these autoantibodies is still unclear, their production by B cells and plasma cells suggests the importance of these cells in the development of SSc. This review narratively examines B-cell dysfunctions and their role in the pathogenesis of SSc and discusses B-cell-targeted therapies currently used or potentially useful for the management of end-organ complications.

Extracellular Matrix-Inspired Dendrimer Nanogels Encapsulating Cyclophosphamide for Systemic Sclerosis Treatment

Cyclophosphamide has a certain therapeutic effect on treating systemic sclerosis (SSc), while difficulties exist in controlling severe systematic side effects and enhancing targeting capacity. Here, inspired from the natural extracellular matrix composition, we propose a cyclophosphamide-encapsulated nanogel based on dendritic polymers polyamidoamine (PAMAM) for SSc treatment. We combine bovine serum albumin and generation 5 (G5) PAMAM dendrimers with polyphenol modification to obtain nanogels featured with antioxidant and anti-inflammatory effects. The nanogels can possess excellent biocompatibility and prevent fibroblasts from oxidative stress damage and TGF-β-mediated activation. Furthermore, in the bleomycin-induced SSc mouse model, dendrimer nanogels encapsulating cyclophosphamide also exhibit the ability to attenuate fibrosis by modulating immunity, suppressing inflammation, and reducing collagen synthesis. These findings underscore the value of this dendritic polymer nanogel in the treatment of chronic SSc, indicating its broader potential for clinical applications.

Cardiac involvement in systemic sclerosis: A critical review of knowledge gaps and opportunities

Cardiovascular complications are observed in up to one-third of patients with systemic sclerosis (SSc). Early identification and management of SSc-associated primary cardiac disease is often challenging, given the complex disease pathophysiology, significant variability in clinical presentation, and scarce disease-modifying therapeutics. Here, we review the molecular mechanisms involved in SSc-associated cardiac disease pathogenesis, novel diagnostic tools and emerging therapies.

CCL24 and Fibrosis: A Narrative Review of Existing Evidence and Mechanisms

Tissue fibrosis results from a dysregulated and chronic wound healing response accompanied by chronic inflammation and angiogenesis. Regardless of the affected organ, fibrosis shares the following common hallmarks: the recruitment of immune cells, fibroblast activation/proliferation, and excessive extracellular matrix deposition. Chemokines play a pivotal role in initiating and advancing these fibrotic processes. CCL24 (eotaxin-2) is a chemokine secreted by immune cells and epithelial cells, which promotes the trafficking of immune cells and the activation of profibrotic cells through CCR3 receptor binding. Higher levels of CCL24 and CCR3 were found in the tissue and sera of patients with fibro-inflammatory diseases, including primary sclerosing cholangitis (PSC), systemic sclerosis (SSc), and metabolic dysfunction-associated steatohepatitis (MASH). This review delves into the intricate role of CCL24 in fibrotic diseases, highlighting its impact on fibrotic, immune, and vascular pathways. We focus on the preclinical and clinical evidence supporting the therapeutic potential of blocking CCL24 in diseases that involve excessive inflammation and fibrosis.

Residual Traditional Risk in Non-Traditional Atherosclerotic Diseases

Individuals with chronic inflammatory and immune disorders are at an increased risk of atherosclerotic events and premature cardiovascular (CV) disease. Despite extensive literature exploring the relationship between "non-traditional" atherosclerotic conditions and CV risk, many aspects remain unresolved, including the underlying mechanisms promoting the "non-traditional CV risk", the development of an innovative and comprehensive CV risk assessment tool, and recommendations for tailored interventions. This review aims to evaluate the available evidence on key "non-traditional" CV risk-enhancer conditions, with a focus on assessing and managing CV risk factors. We conducted a comprehensive review of 412 original articles, narrative and systematic reviews, and meta-analyses addressing the CV risk associated with "non-traditional" atherosclerotic conditions. The analysis examined the underlying mechanisms of these relationships and identified strategies for assessing and mitigating elevated risk. A major challenge highlighted is the difficulty in quantifying the contribution of individual risk factors and disease-specific elements to CV risk. While evidence supports the cardiovascular benefits of statins beyond lipid lowering, such as pleiotropic and endothelial effects, current guidelines lack specific recommendations for the use of statins or other therapies targeting non-traditional CV risk factors. Additionally, the absence of validated cardiovascular risk scores that incorporate non-traditional risk factors hinders accurate CV risk evaluation and management. The growing prevalence of "non-traditional CV risk-enhancer conditions" underscores the need for improved awareness of CV risk assessment and management. A thorough understanding of all contributing factors, including disease-specific elements, is crucial for accurate prediction of cardiovascular disease (CVD) risk. This represents an essential foundation for informed decision-making in primary and secondary prevention. We advocate for future research to focus on developing innovative, disease-specific CV risk assessment tools that incorporate non-traditional risk factors, recognizing this as a promising avenue for translational and clinical outcome research.

Gut-Heart Axis: Microbiome Involvement in Restrictive Cardiomyopathies

An intriguing aspect of restrictive cardiomyopathies (RCM) is the microbiome role in the natural history of the disease. These cardiomyopathies are often difficult to diagnose and so result in significant morbidity and mortality. The human microbiome, composed of billions of microorganisms, influences various physiological and pathological processes, including cardiovascular health. Studies have shown that gut dysbiosis, an imbalance in the composition of intestinal bacteria, can contribute to systemic inflammation, a key factor in many cardiovascular conditions. An increase in gut permeability, frequently caused by dysbiosis, allows bacterial endotoxins to enter the bloodstream, activating inflammatory pathways that exacerbate cardiac dysfunction. Recent reports highlight the potential role of microbiome in amyloidogenesis, as certain bacteria produce proteins that accelerate the formation of amyloid fibrils. Concurrently, advancements in amyloidosis treatments have sparked renewed hopes, marking a promising era for managing these kinds of diseases. These findings suggest that the gut-heart axis may be a potential factor in the development and progression of cardiovascular disease like RCM, opening new paths for therapeutic intervention. The aim of this review is to provide a detailed overview of the gut-heart axis, focusing on RCM.

Association of nutritional status indices with gastrointestinal symptoms in systemic sclerosis: a cross-sectional study

Gastrointestinal (GI) involvement is highly prevalent in systemic sclerosis (SSc) and significantly affects patient quality of life and clinical outcomes. This study investigates the potential of undernutrition scores, namely the Control of Nutritional Status (CONUT) score and the Prognostic Nutrition Index (PNI), in predicting GI involvement in patients with SSc. A total of 82 patients diagnosed with SSc were enrolled in this cross-sectional study. Participants were evaluated using the UCLA Scleroderma Clinical Research Consortium Gastrointestinal Tract 2.0 (UCLA GIT 2.0) tool, which assesses the severity of GI symptoms and their impact on health-related quality of life. Malnutrition was assessed using CONUT and PNI scores derived from routine laboratory parameters. The correlation between these malnutrition indices and the UCLA GIT 2.0 scores was analyzed to determine the predictive value of malnutrition in GI involvement. The study found that patients with higher CONUT scores, indicating malnutrition, had significantly higher total UCLA GIT 2.0 scores. A moderate positive correlation was observed between CONUT scores and total UCLA GIT 2.0 scores (r =.539; p <.01), while a negative correlation was found between CONUT scores and PNI (r = -.513; p <.01). These findings suggest that malnutrition, as measured by CONUT and PNI, is associated with greater GI involvement in SSc. This study shows that malnutrition indices such as CONUT and PNI in SSc patients, together with the UCLA GIT 2.0 score, may serve as usefull predictors of GI involvment in routine clinical practice.

Common biomarkers of idiopathic pulmonary fibrosis and systemic sclerosis based on WGCNA and machine learning

Interstitial lung disease (ILD) is known to be a major complication of systemic sclerosis (SSc) and a leading cause of death in SSc patients. As the most common type of ILD, the pathogenesis of idiopathic pulmonary fibrosis (IPF) has not been fully elucidated. In this study, weighted correlation network analysis (WGCNA), protein‒protein interaction, Kaplan-Meier curve, univariate Cox analysis and machine learning methods were used on datasets from the Gene Expression Omnibus database. CCL2 was identified as a common characteristic gene of IPF and SSc. The genes associated with CCL2 expression in both diseases were enriched mainly in chemokine-related pathways and lipid metabolism-related pathways according to Gene Set Enrichment Analysis. Single-cell RNA sequencing (sc-RNAseq) revealed a significant difference in CCL2 expression in alveolar epithelial type 1/2 cells, mast cells, ciliated cells, club cells, fibroblasts, M1/M2 macrophages, monocytes and plasma cells between IPF patients and healthy donors. Statistical analyses revealed that CCL2 was negatively correlated with lung function in IPF patients and decreased after mycophenolate mofetil (MMF) treatment in SSc patients. Finally, we identified CCL2 as a common biomarker from IPF and SSc, revealing the common mechanism of these two diseases and providing clues for the study of the treatment and mechanism of these two diseases.

Advances in chimeric antigen receptor T cell therapy for autoimmune and autoinflammatory diseases and their complications

Chimeric antigen receptor T (CAR-T) cells are genetically engineered T cells expressing transmembrane chimeric antigen receptors with specific targeting abilities. As an emerging immunotherapy, the use of CAR-T cells has made significant breakthroughs in cancer treatment, particularly for hematological malignancies. The success of CAR-T cell therapy in blood cancers highlights its potential for other conditions in which the clearance of pathological cells is therapeutic, such as liver diseases, infectious diseases, heart failure, and diabetes. Given the limitations of current therapies for autoimmune diseases, researchers have actively explored the potential therapeutic value of CAR-T cells and their derivatives in the field of autoimmune diseases. This review focuses on the research progress and current challenges of CAR-T cells in autoimmune diseases with the aim of providing a theoretical basis for the precise treatment of autoimmune diseases. In the future, CAR-T cells may present new therapeutic modalities and ultimately provide hope for patients with autoimmune diseases.

EULAR recommendations for the treatment of systemic sclerosis: 2023 update

OBJECTIVES

To update the 2017 European Alliance of Associations for Rheumatology (EULAR) recommendations for treatment of systemic sclerosis (SSc), incorporating new evidence and therapies.

METHODS

An international task force was convened in line with EULAR standard operating procedures. A nominal group technique exercise was performed in two rounds to define questions underpinning a subsequent systematic literature review. The evidence derived was discussed and overarching principles, recommendations and future research agenda were iteratively developed with voting rounds.

RESULTS

The task force agreed on 22 recommendations covering 8 clinical/organ domains including Raynaud's phenomenon, digital ulcers, pulmonary arterial hypertension, scleroderma renal crisis, skin fibrosis, interstitial lung disease (ILD), gastrointestinal manifestations and arthritis. Most new recommendations are related to skin fibrosis and ILD. These included novel recommendations for the use of mycophenolate mofetil, nintedanib, rituximab and tocilizumab for the treatment of these crucial disease manifestations. The recommendations also included first-line and second-line interventions, providing increased utility for rheumatology practitioners. Important additions to the future research agenda included consideration of novel interventions for the management of vascular, musculoskeletal and gastrointestinal manifestations and calcinosis, as well as for the local management of digital ulcers.

CONCLUSION

These updated recommendations include the first set of synthetic and biological targeted therapies recommended for key fibrotic manifestations of SSc as well as first-line combination treatment for newly diagnosed pulmonary artery hypertension and prioritise a new research agenda for the coming years.

Toll-Like Receptor 8 is Expressed in Monocytes in Contrast to Plasmacytoid Dendritic Cells and Mediates Aberrant Interleukin-10 Responses in Patients With Systemic Sclerosis

OBJECTIVE

Systemic sclerosis (SSc) is a severe rheumatic disease causing fibrotic tissue rearrangement. Aberrant toll-like receptor (TLR) 8 transcripts in plasmacytoid dendritic cells (pDCs) were recently linked to SSc pathogenesis, which is at least partially mediated by increased type I interferon (IFN-I) responses. Here, we addressed the functional role of TLR8 signaling in different immune cell subsets of patients with SSc.

METHODS

Monocytes, conventional dendritic cells (cDCs), and pDCs from the blood and skin of patients with SSc were analyzed for TLR8 protein expression. To assess TLR function, cytokine responses upon TLR7 and TLR8 stimulation were studied. To identify relevant alterations specific for patients with SSc (n = 16), patients with primary Sjögren disease (pSS; n = 10) and healthy controls (HCs; n = 13) were included into the study.

RESULTS

In all individuals, TLR8 was expressed in monocytes and cDCs but not in pDCs. The TLR8 expression levels were overall similar in patients with SSc and pSS and HCs. Additionally, in all study participants, TLR8 stimulation of pDCs did not induce IFN-I expression. In contrast, monocytes from patients with SSc revealed increased interleukin (IL)-10 responses upon TLR8 (patients with SSc vs HCs, P = 0.0126) and TLR7/8 stimulation (patients with SSc vs HCs, P = 0.0170).

CONCLUSION

TLR8 protein is not expressed in pDCs of patients with SSc. Accordingly, they do not respond to TLR8 stimulation. In contrast, monocytes of patients with SSc respond to TLR8 stimulation with increased IL-10 responses. Therefore, TLR8 signaling in monocytes participates in SSc pathogenesis by conferring aberrant IL-10 expression.

Diversity and Epitope Spreading of Anti-RNA Polymerase III Antibodies in Systemic Sclerosis: A Potential Biomarker for Skin and Lung Involvement

OBJECTIVE

Epitope spreading (ES), involving autoantibodies, plays a crucial role in the development and persistence of autoimmune reactions in various autoimmune diseases. This study aimed to investigate the relationship between ES of anti-RNA polymerase III (RNAP III) antibodies (ARAs) and the clinical manifestations of systemic sclerosis (SSc).

METHODS

We investigated whether intermolecular ES occurs in the subunits of the RNAP III complex and whether intramolecular ES targets the major antigen, RNA polymerase III subunit A (RPC1), in patients with SSc. To achieve this, we synthesized 17 full-length subunit proteins of the RNAP III complex and 5 truncated forms of RPC1 in vitro using a wheat germ cell-free translation system. Subsequently, we prepared antigen-binding plates and measured autoantibodies in the serum of patients with SSc.

RESULTS

Autoantibodies against different RNAP III complex subunits were found in patients who were ARA-positive with SSc. The intermolecular ES indicators significantly correlated with the modified Rodnan skin thickness score (mRSS) and surfactant protein-D, a biomarker of interstitial lung disease. However, the extent of disease on high-resolution computed tomography or pulmonary function tests did not show any significant correlation. Intramolecular ES indicator against RPC1 were significantly correlated with mRSS and renal crisis. Furthermore, longitudinal assessment of ES in RNAP III complex subunits correlated with mRSS and exhibited potential as a disease activity biomarker.

CONCLUSION

Our findings indicate a correlation between ES levels and the severity of skin sclerosis or the risk of other complications in SSc. This study suggests that measuring ES in SSc serves as a novel biomarker for disease activity.

Neurovascular dysregulation in systemic sclerosis: novel insights into pathophysiology, diagnosis, and treatment utilizing invasive cardiopulmonary exercise testing

PURPOSE OF REVIEW

Pathologic abnormalities in skeletal muscle and the systemic vasculature are common in patients with systemic sclerosis (SSc). These abnormalities may lead to impaired systemic peripheral oxygen extraction (EO 2 ), known as neurovascular dysregulation, which may be because of abnormal blood flow distribution in the vasculature, microvascular shunting, and/or skeletal muscle mitochondrial dysfunction. Findings from invasive cardiopulmonary exercising testing (iCPET) provide important insights and enable diagnosis and treatment of this SSc disease manifestation.

RECENT FINDINGS

Recent findings from noninvasive cardiopulmonary exercise testing (niCPET) support the existence of neurovascular dysregulation in patients with SSc. Invasive cardiopulmonary exercise testing (iCPET) has pointed to reduced systemic vascular distensibility as a possible mechanism for neurovascular dysregulation in patients with connective tissue diseases, including SSc.

SUMMARY

Neurovascular dysregulation is likely an underappreciated cause of exercise impairment and dyspnea in patients with SSc in the presence or absence of underlying cardiopulmonary disease. It is posited to be related to microcirculatory and muscle dysfunction. Further studies are needed to clarify the pathophysiology of neurovascular dysregulation in SSc and to identify novel treatment targets and additional therapies.

Innovative cell therapies for systemic sclerosis: available evidence and new perspectives

INTRODUCTION

Systemic sclerosis (SSc) is the rheumatic disease with the highest individual mortality rate with a detrimental impact on quality of life. Cell-based therapies may offer new perspectives for this disease as recent phase I trials support the safety of IV infusion of allogeneic mesenchymal stromal cells in SSc and case reports highlight the potential use of Chimeric Antigen Receptor (CAR)-T cells targeting CD19 in active SSc patients who have not responded to conventional immunosuppressive therapies.

AREAS COVERED

This narrative review highlights the most recent evidence supporting the use of cellular therapies in SSc as well as their potential mechanisms of action and discusses future perspectives for cell-based therapies in SSc. Medline/PubMed was used to identify the articles of interest, using the keywords 'Cellular therapies,' 'Mesenchymal stromal cells,' 'Chimeric Antigen Receptor' AND 'systemic sclerosis.' Milestones articles reported by the authors were also used.

EXPERT OPINION

Cellular therapies may represent an opportunity for long-term remission/cure in patients with different autoimmune diseases, including SSc who have not responded to conventional therapies. Multiple ongoing phase I/II trials will provide greater insights into the efficacy and toxicity of cellular therapies.

The role of GRB2 in diabetes, diabetes complications and related disorders

Growth factor receptor-bound protein 2 (GRB2) is a key adaptor protein involved in multiple signalling pathways, and its dysregulation is associated with various diseases. Type 2 diabetes is a systemic condition characterized by insulin resistance and impaired β-cell function. The complications of diabetes significantly reduce life expectancy and quality of life, imposing a substantial burden on society. However, the role of GRB2 in diabetes and associated complications is largely unknown. Emerging evidence suggests that GRB2 plays a crucial role in insulin resistance, inflammation, immune activation and the regulation of cellular processes such as cell proliferation, growth, metabolism, angiogenesis, apoptosis and differentiation. Dysregulation of GRB2-mediated pathways contributes to the progression of diabetic neuropathy, cognitive dysfunction, nephropathy, retinopathy and related disorders. This review provides a comprehensive overview of the current understanding of the role of GRB2 in diabetes, diabetes complications and related disorders, alongside recent advances in the development of GRB2-targeted therapies. Elucidating the complex role of GRB2 in these disorders provides valuable insights into potential therapeutic strategies targeting GRB2-mediated pathways.

Single-cell transcriptomic profiling of lung fibroblasts in a bleomycin-induced systemic sclerosis mouse model

Systemic sclerosis (SSc) is a complex autoimmune disease characterized by fibrosis, vascular abnormalities, and immune dysfunction, with no definitive cure. Patients with progressive pulmonary fibrosis face a high mortality risk, underscoring the urgent need for effective treatments. Although fibroblasts are recognized as key drivers of fibrosis, the precise molecular mechanisms remain poorly understood. In this study, we employ single-cell RNA sequencing to explore the role of fibroblasts in pulmonary fibrosis. Using a mouse model induced by subcutaneous bleomycin administration, we identify two distinct fibroblast subpopulations: nephronectin-positive (NPNT) and peptidase inhibitor 16-positive cells(PI16). NPNT-positive fibroblasts, located around the alveoli, exhibit increased extracellular matrix expression following bleomycin treatment. To further understand pulmonary fibrosis, subcutaneous and intratracheal bleomycin-induced mouse models are compared. A comparative gene expression analysis reveals shared and unique features between the models, highlighting the complexity of the fibrotic process. These findings offer valuable insights into the molecular mechanisms of SSc-associated pulmonary fibrosis and may inform the development of therapies targeting specific fibroblast subpopulations or pathways.

The Role of Cardiac Magnetic Resonance Imaging Parameters in Prognostication of Systemic Sclerosis in Patients with Cardiac Involvement: A Systematic Review of the Literature

BACKGROUND

Systemic sclerosis (SSc) is an immune dysregulation disorder affecting multiple organs. Cardiac involvement, prevalently myocardial, is associated with poor outcomes in SSc patients. Several investigations explored the role of cardiac magnetic resonance (CMR) imaging in the diagnosis of scleroderma-related cardiomyopathy and analyzed the clinical, radiologic, and pathologic correlations utilizing CMR examinations. However, fewer studies investigated the role of traditional and novel CMR parameters, including functional values, strain, late gadolinium enhancement (LGE), and parametric mapping variables, in predicting outcomes in SSc patients. We aimed to review the literature to seek for the role of different CMR features in outcome prediction of SSc patients.

METHODS

We systematically reviewed PubMed/Medline, EMBASE, Web of Science, and Scopus databases to find publications that analyzed the prognostic value of CMR-derived parameters for adverse events, particularly all-cause mortality, in SSc patients published from January of 1960, up to the May 1, 2023. In this regard, we excluded the reviews, editorials, case reports, and case series. Also, we excluded the studies with the target population possessing obstructive coronary artery disease, other rheumatologic conditions, moderate to severe pulmonary hypertension and history of intervention for arrhythmia. Two of the authors principally extracted data, and disagreements were resolved through consensus. Information from each investigation was registered. Two of the authors utilized the Quality in Prognostic Studies (QUIPS) tool for risk of bias assessment, and a third reviewer was involved in cases of inconsistencies. Consequently, the main findings of the conducted projects were outlined and depicted in tables.

RESULTS

The initial search yielded 4623 papers. After removing duplicates and irrelevant titles/abstracts, 120 full-text articles were reviewed. Nine studies met the criteria with study population ranging from 24 to 260 patients in included studies. The following CMR parameters were powerful predictors of all-cause mortality: myocardial LGE, native T1 value, extracellular volume (ECV), and ventricular strain. Although less studied, left atrial strain, diffusion/perfusion, and stress-CMR parameters were also predictors of outcomes.

DISCUSSION

In SSc patients, CMR findings, including myocardial LGE, native T1 value, ECV, and ventricular strain values, were robust predictors of adverse outcomes. Other CMR parameters, consisting of diffusion/perfusion and stress-CMR values, were less studied. A drawback encountered while we were reviewing the studies was the versatility of measurement criteria among the included studies that precluded us from driving a meta-analysis. Further longitudinal multiparametric CMR studies are required to investigate the prognostic role of CMR examination in SSc patients.

REGISTRATION

The systematic review protocol containing the planned methods was registered in PROSPERO before starting the review process (PROSPERO, registration ID: CRD42023446391).

Immunometabolic shifts in autoimmune disease: Mechanisms and pathophysiological implications

Autoimmune diseases occur when the immune system abnormally attacks the body's normal tissues, causing inflammation and damage. Each disease has unique immune and metabolic dysfunctions during pathogenesis. In rheumatoid arthritis (RA), immune cells have different metabolic patterns and mitochondrial/lysosomal dysfunctions at different disease stages. In systemic lupus erythematosus (SLE), type I interferon (IFN) causes immune cell metabolic dysregulation, linking activation to metabolic shifts that may worsen the disease. In systemic sclerosis (SSc), mitochondrial changes affect fibroblast metabolism and the immune response. Idiopathic inflammatory myopathies (IIMs) patients have mitochondrial and metabolic issues. In primary Sjögren's syndrome (pSS), immune cell metabolism is imbalanced and mitochondrial damage can lead to cell/tissue damage. Metabolic reprogramming links cellular energy needs and immune dysfunctions, causing inflammation, damage, and symptoms in these diseases. It also affects immune cell functions like differentiation, proliferation, and secretion. This review discusses the potential of targeting metabolic pathways to restore immune balance, offering directions for future autoimmune disease research and treatment.

Aberrant Chitinase 3-Like 1 Expression in Basal Cells Contributes to Systemic Sclerosis Fibrosis

Systemic sclerosis (SSc) is an autoimmune disease characterized by extensive skin and internal organ fibrosis. However, the mechanism underlying fibrosis remains unclear, and effective treatments for halting or reversing fibrosis are lacking. In this study, single-cell RNA sequencing is used to obtain a comprehensive overview of skin cells from patients with SSc and healthy controls. A subset of basal cells with high chitinase 3-like 1 (Chi3L1) expression, which potentially plays an important role in fibroblast activation, is identified in SSc. Subsequently, patients with SSc are present with increased expression of Chi3L1 in the skin and serum, and elevated serum levels are associated with skin induration and pulmonary function. Furthermore, Chi3L1 promoted the differentiation of SSc dermal fibroblasts into myofibroblasts, and Chi3L1-deficient (Chi3L1-/-) mice showed amelioration of fibrosis in a bleomycin-induced SSc (BLM-SSc) model. Mechanistically, Chi3L1 mediates fibroblast activation primarily by interacting with interleukin-17 receptor A (IL-17RA), thereby initiating downstream nuclear factor kappa B and mitogen-activated protein kinases signaling pathways. Moreover, the anti-fibrotic effect of IL-17RA antagonists in BLM-SSc mice is demonstrated. In conclusion, Chi3L1 is a potential biomarker for the degree of fibrosis in SSc. Chi3L1 and its receptor, IL-17RA, are promising therapeutic targets for patients with SSc.

Inhibiting triggering receptor expressed on myeloid cells 1 signaling to ameliorate skin fibrosis

Systemic sclerosis (SSc) is characterized by immune system failure, vascular insult, autoimmunity, and tissue fibrosis. TGF-β is a crucial mediator of persistent myofibroblast activation and aberrant extracellular matrix production in SSc. The factors responsible for this are unknown. By amplifying pattern recognition receptor signaling, triggering receptor expressed on myeloid cells 1 (TREM-1) is implicated in multiple inflammatory conditions. In this study, we used potentially novel ligand-independent TREM-1 inhibitors in preclinical models of fibrosis and explanted SSc skin fibroblasts in order to investigate the pathogenic role of TREM-1 in SSc. Selective pharmacological TREM-1 blockade prevented and reversed skin fibrosis induced by bleomycin in mice and mitigated constitutive collagen synthesis and myofibroblast features in SSc fibroblasts in vitro. Our results implicate aberrantly activated TREM-1 signaling in SSc pathogenesis, identify a unique approach to TREM-1 blockade, and suggest a potential therapeutic benefit for TREM-1 inhibition.

Psychological features of systemic sclerosis: results from an observational study

Objectives

(a) Assessing mental disorders, psychological distress, psychological wellbeing in patients with systemic sclerosis (SSc); (b) identifying psychological features independently contributing to the status of having the diagnosis of SSc.

Methods

Two hundred SSc outpatients were compared with 100 healthy subjects. Mental disorders were assessed via the Mini International Neuropsychiatric Interview (MINI). Self-reported rating scales were administered: Health Assessment Questionnaire Disability Index (HAQ-DI), Symptom Checklist-90-Revised (SCL-90-R), Psychological Well Being scales (PWB). General linear models allowed to verify which psychological feature would individually make unique contributions to overall status of having the diagnosis of SSc.

Results

Major depressive episode/disorder, panic disorder were more prevalent among patients with SSc (p < 0.05); SCL-90-R somatization and depression were more severe (p < 0.05) in SSc; PWB personal growth, positive relationships with others, purposes in life were poorer (p < 0.05) in patients with SSc if compared to healthy controls. The final general linear model, accounting for 20.4% of variance, showed that having the diagnosis of SSc was associated to lower SCL-90-R paranoid ideation and poorer PWB relationships with others.

Conclusion

SSc showed to present psychological features in need of assessment since some of them individually made unique contributions to overall status of having the SSc diagnosis.

The Role of Pharmacometrics in Advancing the Therapies for Autoimmune Diseases

Autoimmune diseases (AIDs) are a group of disorders in which the immune system attacks the body's own tissues, leading to chronic inflammation and organ damage. These diseases are difficult to treat due to variability in drug PK among individuals, patient responses to treatment, and the side effects of long-term immunosuppressive therapies. In recent years, pharmacometrics has emerged as a critical tool in drug discovery and development (DDD) and precision medicine. The aim of this review is to explore the diverse roles that pharmacometrics has played in addressing the challenges associated with DDD and personalized therapies in the treatment of AIDs. Methods: This review synthesizes research from the past two decades on pharmacometric methodologies, including Physiologically Based Pharmacokinetic (PBPK) modeling, Pharmacokinetic/Pharmacodynamic (PK/PD) modeling, disease progression (DisP) modeling, population modeling, model-based meta-analysis (MBMA), and Quantitative Systems Pharmacology (QSP). The incorporation of artificial intelligence (AI) and machine learning (ML) into pharmacometrics is also discussed. Results: Pharmacometrics has demonstrated significant potential in optimizing dosing regimens, improving drug safety, and predicting patient-specific responses in AIDs. PBPK and PK/PD models have been instrumental in personalizing treatments, while DisP and QSP models provide insights into disease evolution and pathophysiological mechanisms in AIDs. AI/ML implementation has further enhanced the precision of these models. Conclusions: Pharmacometrics plays a crucial role in bridging pre-clinical findings and clinical applications, driving more personalized and effective treatments for AIDs. Its integration into DDD and translational science, in combination with AI and ML algorithms, holds promise for advancing therapeutic strategies and improving autoimmune patients' outcomes.

Autoimmune dysphagia

PURPOSE OF REVIEW

Dysphagia is a complication of several autoimmune rheumatic diseases and otorhinolaryngologists are likely to be involved in the assessment and management of patients with such conditions. This review provides an update on rheumatic diseases that may cause swallowing impairment, with particular focus on the epidemiology, pathophysiology and management of dysphagia in these conditions.

RECENT FINDINGS

Dysphagia is a common complication of the following rheumatic diseases: idiopathic inflammatory myopathies, systemic sclerosis, Sjogren's syndrome, systemic lupus erythematosus and rheumatoid arthritis. It may also be a complication of rarer autoimmune conditions such as Bechet's syndrome, sarcoidosis and granulomatosis with polyangiitis. All three stages of swallowing (oral, pharyngeal and oesophageal) may be impaired in these conditions. Both medical therapy and surgical intervention play an important role in the management of autoimmune dysphagia.

SUMMARY

The investigation and management of autoimmune dysphagia requires close collaboration between rheumatologists and otorhinolaryngologists. There is a need for further research to establish standardised guidelines on the assessment and management of autoimmune dysphagia.

SUMO: A new perspective to decipher fibrosis

Fibrosis is characterized by excessive extracellular matrix (ECM) deposition resulting from dysregulated wound healing and connective tissue repair mechanisms. Excessive accumulation of ECM leads to fibrous tissue formation, impairing organ function and driving the progression of various fibrotic diseases. Recently, the role of small ubiquitin-like modifiers (SUMO) in fibrotic diseases has attracted significant attention. SUMO-mediated SUMOylation, a highly conserved posttranslational modification, participates in a variety of biological processes, including nuclear-cytosolic transport, cell cycle progression, DNA damage repair, and cellular metabolism. Conversely, SUMO-specific proteases cleave the isopeptide bond of SUMO conjugates, thereby regulating the deSUMOylation process. Mounting evidence indicates that SUMOylation and deSUMOylation regulate the functions of several proteins, such as Smad3, NF-κB, and promyelocytic leukemia protein, which are implicated in fibrotic diseases like liver fibrosis, myocardial fibrosis, and pulmonary fibrosis. This review summarizes the role of SUMO in fibrosis-related pathways and explores its pathological relevance in various fibrotic diseases. All evidence suggest that the SUMO pathway is important targets for the development of treatments for fibrotic diseases.

Critical Analysis of Cytoplasmic Progression of Inflammatory Signaling Suggests Potential Pharmacologic Targets for Wound Healing and Fibrotic Disorders

Successful skin wound healing is dependent on an interplay between epidermal keratinocytes and dermal fibroblasts as they react to local extracellular factors (DAMPs, PAMPs, cytokines, etc.) surveyed from that environment by numerous membrane receptors (e.g., TLRs, cytokine receptors, etc.). In turn, those receptors are the start of a cytoplasmic signaling pathway where balance is key to effective healing and, as needed, cell and matrix regeneration. When directed through NF-κB, these signaling routes lead to transient responses to the benefit of initiating immune cell recruitment, cell replication, local chemokine and cytokine production, and matrix protein synthesis. The converse can also occur, where ongoing canonical NF-κB activation leads to chronic, hyper-responsive states. Here, we assess three key players, TAK1, TNFAIP3, and TNIP1, in cytoplasmic regulation of NF-κB activation, which, because of their distinctive and yet inter-related functions, either promote or limit that activation. Their balanced function is integral to successful wound healing, given their significant control over the expression of inflammation-, fibrosis-, and matrix remodeling-associated genes. Intriguingly, these three proteins have also been emphasized in dysregulated NF-κB signaling central to systemic sclerosis (SSc). Notably, diffuse SSc shares some tissue features similar to an excessive inflammatory/fibrotic wound response without eventual resolution. Taking a cue from certain instances of aberrant wound healing and SSc having some shared aspects, e.g., chronic inflammation and fibrosis, this review looks for the first time, to our knowledge, at what those pathologies might have in common regarding the cytoplasmic progression of NF-κB-mediated signaling. Additionally, while TAK1, TNFAIP3, and TNIP1 are often investigated and reported on individually, we propose them here as three proteins whose consequences of function are very highly interconnected at the signaling focus of NF-κB. We thus highlight the emerging promise for the eventual clinical benefit derived from an improved understanding of these integral signal progression modulators. Depending on the protein, its indirect or direct pharmacological regulation has been reported. Current findings support further intensive studies of these points in NF-κB regulation both for their basic function in healthy cells as well as with the goal of targeting them for translational benefit in multiple cutaneous wound healing situations, whether stemming from acute injury or a dysregulated inflammatory/fibrotic response.

Vascular endothelial growth factor as a potential biomarker in systemic sclerosis: a systematic review and meta-analysis

Introduction

Systemic sclerosis (SSc), a chronic autoimmune condition, is characterized by microvascular dysfunction, ineffective angiogenesis, and fibrosis. The identification of robust biomarkers reflecting these processes may assist in clinical management and lead to the discovery of new therapies. We sought to address this issue by conducting a systematic review and meta-analysis of studies investigating one such biomarker, vascular endothelial growth factor (VEGF), in SSc patients and healthy controls and in SSc patients with localized or diffuse disease, different video capillaroscopy patterns (early, active, or late), and presence or absence of complications.

Methods

We searched PubMed, Scopus, and Web of Science from inception to 15 May 2024. We assessed the risk of bias and the certainty of evidence using the JBI checklist for analytical studies and GRADE, respectively.

Results

In 42 eligible studies, compared to controls, patients with SSc had significantly higher plasma or serum VEGF concentrations (standard mean difference, SMD=0.93, 95% CI 0.71 to 1.15, p<0.001; moderate certainty). In further analyses, VEGF concentrations were significantly higher in SSc patients with diffused disease than those with localized disease (SMD=0.30, 95% CI 0.01 to 0.59, p=0.046; very low certainty), in patients with late vs. active video capillaroscopy pattern (SMD=0.35, 95% CI 0.09 to 0.61, p=0.008; very low certainty), and in patients with pulmonary hypertension than those without (SMD=0.93, 95% CI 0.34 to 1.53, p=0.002; very low certainty). By contrast, no significant differences were observed between SSc patients with and without digital ulcers, interstitial lung disease, and telangiectasias, whereas limited evidence was available for alveolitis. Meta-regression and subgroup analysis of studies investigating VEGF in SSc patients and controls showed no significant associations between the effects size and various patient and study characteristics, including SSc duration and use of corticosteroids, immunosuppressors and vasodilators. By contrast, significant associations were observed with the geographical location where the study was conducted.

Discussion

The results of this systematic review and meta-analysis suggest that VEGF can be useful in the assessment and management of SSc and in the identification of novel therapeutic strategies in this patient group.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero, identifier CRD42024552925.

Impact of gastrointestinal symptoms and psychological distress on quality of life in systemic sclerosis: a cross-sectional study

BACKGROUND

Systemic sclerosis (SSc) is a chronic autoimmune disease characterised by microvascular damage and fibrosis. Mortality in patients with SSc has significantly decreased. Consequently, patients with SSc have longer life expectancy, and health-related quality of life (HrQoL) has become more relevant in the comprehensive management of the disease.

OBJECTIVE

To evaluate the impact between gastrointestinal (GI) symptom burden and psychological well-being on HrQoL in patients with SSc.

DESIGN

Nested cross-sectional study conducted between January and July 2022.

PARTICIPANTS

A single-centre cohort of 166 patients with SSc, including 103 (55%) with limited cutaneous SSc, 43 (24%) with diffuse SSc and 37 (21%) with sine-sclerosis SSc.

MAIN MEASURES

GI symptom burden was assessed using the University of California Los Angeles Scleroderma Clinical Trial Consortium gastrointestinal tract 2.0 (UCLA SCTC GIT 2.0) questionnaire, psychological well-being was measured with the Hospital Anxiety and Depression Scale (HADS), and HrQoL was evaluated using the Short Form 36 (SF-36) questionnaire. Demographic, clinical and immunological data were collected from a prospectively maintained database.

KEY RESULTS

Patients with moderate to severe GI symptoms (UCLA SCTC GIT 2.0 score >0.5, n=95, 57%) reported decreased HrQoL in all subdomains except vitality by SF-36, and higher anxiety and depression scores by HADS (all p<0.05). The severity of GI symptom burden and depression were independently associated with a decline in the physical component of QoL (β=-0.273 and β=-0.411, respectively, p<0.01 for both). Only the severity of depression and anxiety (β=-0.482 and β=-0.213, respectively, p<0.05), but not GI symptom burden, were independently associated with a decline in the mental component of QoL.

CONCLUSIONS

Our data suggest that in patients with SSc, GI and psychological burden negatively influence quality of life independently, highlighting the need for a holistic approach to patient's care.

Performance of the EULAR Systemic sclerosis Impact of Disease (ScleroID) questionnaire as a patient-reported outcome measure for patients with diffuse systemic sclerosis

OBJECTIVE

Systemic sclerosis Impact of Disease (ScleroID) is the first comprehensive patient-reported outcome measure (PROM) specifically developed for systemic sclerosis (SSc). We investigated the performance of ScleroID in patients with diffuse cutaneous SSc (dcSSc), as a prerequisite for its use in randomised controlled trials (RCTs) testing potentially disease-modifying drugs.

METHODS

All patients with dcSSc from the large, multicentric, ScleroID cohort were included. SSc-Health Assessment Questionnaire (HAQ), EuroQol-5 Dimensions and 36-item Short Form Health Survey (SF-36) were used as comparators. The study includes a longitudinal arm with a reliability visit at 7±3 days and a 12 months follow-up visit. The performance of ScleroID in dcSSc was assessed according to the Outcome Measures in Rheumatology filter.

RESULTS

In total, 152 dcSSc patients were analysed (29% male, median age 54 years). ScleroID reflected well the disease impact of dcSSc, showing a good construct validity with high Spearman's correlation coefficients with comparators (SSc-HAQ, 0.79, 95% CI (0.69, 0.86); HAQ-Disability Index, 0.72 95% CI (0.60, 0.80); SF-36 physical score, -0.69 95% CI (-0.77, -0.60)). The internal consistency was strong (Cronbach's alpha 0.87, split-half reliability coefficient 0.88).In the longitudinal arm, 44 patients had a reliability visit and 113 had a follow-up visit, of whom 19/113 (17%) reported a significant change (11 improved, 8 worsened). ScleroID showed a good consistency and discriminative ability with excellent test-retest reliability (intraclass correlation coefficient 0.89, 95% CI (0.84, 0.92)) and moderate sensitivity to change (standardised response mean -0.63 in the improved subgroup and 0.48 in the worsened subgroup), but superior to the comparators.

CONCLUSION

The European Alliance of Associations for Rheumatology (EULAR) ScleroID performs well for patients with dcSSc. This supports its inclusion and regular assessment as PROM in RCTs.

Research Progress of Fibroblasts in Human Diseases

Fibroblasts, which originate from embryonic mesenchymal cells, are the predominant cell type seen in loose connective tissue. As the main components of the internal environment that cells depend on for survival, fibroblasts play an essential role in tissue development, wound healing, and the maintenance of tissue homeostasis. Furthermore, fibroblasts are also involved in several pathological processes, such as fibrosis, cancers, and some inflammatory diseases. In this review, we analyze the latest research progress on fibroblasts, summarize the biological characteristics and physiological functions of fibroblasts, and delve into the role of fibroblasts in disease pathogenesis and explore treatment approaches for fibroblast-related diseases.

Prevalence of hybrid TLR4+M2 monocytes/macrophages in peripheral blood and lung of systemic sclerosis patients with interstitial lung disease

Introduction

Systemic sclerosis (SSc) is a complex autoimmune connective tissue disease characterized by microvascular damage, immune system reactivity and progressive fibrosis of skin and internal organs. Interstitial lung disease is the leading cause of death for SSc patients (SSc-ILD), and the process of lung fibrosis involves also circulating monocytes and alveolar macrophages.

Methods

Current study aimed to identify monocyte/macrophage phenotypes in lung and peripheral blood of SSc-ILD patients by immunostaining and flow cytometry, respectively. Single immunostaining was performed using primary antibodies against CD68 (pan-macrophage marker), CD80, CD86, TLR4 (M1 markers), CD163, CD204, and CD206 (M2 markers). Flow cytometry analysis included the evaluation of CD45, CD14, CD16 (monocyte lineage), CD1c (dendritic lineage), together with M1 and M2 activation markers on circulating monocytes. Protein synthesis of TLR4 and M2 markers was also investigated in cultured monocytes-derived macrophages (MDMs) from SSc-ILD patients by Western Blotting.

Results

Lung samples were obtained from 9 SSc-ILD patients (50 ± 9 years old) and 5 control non-SSc patients without lung fibrosis (58 ± 23 years old). Alveolar macrophages (CD68+ cells) showed a significantly higher positivity of M1 and M2 markers in SSc-ILD lung samples than in controls (p<0.05 for CD80, p<0.01 for CD86, p<0.001 for CD68, p<0.0001 for TLR4, CD163, CD204 and CD206). In CD68 positive areas of SSc-ILD samples, a significantly higher percentage of TLR4, CD163, CD204, and CD206 positive cells was observed compared to CD80 and CD86 positive cells (p<0.001 in both cases), suggesting the possible presence of hybrid TLR4+M2 macrophages (CD68+CD80-CD86-TLR4+CD163+CD204+CD206+cells) in SSc-ILD samples. A second cohort of 26 SSc-ILD patients (63 ± 14 years old) and 14 SSc patients without ILD (63 ± 19 years old) was recruited for flow cytometry analysis of circulating monocytes. Again, a significantly higher percentage of hybrid TLR4+M2 monocytes (CD1c-CD80-TLR4+CD163+CD204+CD206+cells) was found in SSc-ILD positive than SSc-ILD negative patients (p<0.05). Moreover, the protein synthesis of TLR4 and M2 markers was also found higher in cultured MDMs obtained from SSc-ILD patients than in MDMs from SSc patients without ILD and this increase was significantly higher for CD163 (p<0.05) and CD206 (p<0.01).

Conclusions

The presence of hybrid TLR4+M2 markers on both circulating monocytes and resident lung macrophages in SSc-ILD patients, is reported for the first time. Therefore, the detection of circulating hybrid TLR4+M2 monocytes in SSc-ILD might represent a further potential biomarker of progressive organ fibrosis, to be searched in blood samples of SSc patients.

Autoimmune disease: a view of epigenetics and therapeutic targeting

Autoimmune diseases comprise a large group of conditions characterized by a complex pathogenesis and significant heterogeneity in their clinical manifestations. Advances in sequencing technology have revealed that in addition to genetic susceptibility, various epigenetic mechanisms including DNA methylation and histone modification play critical roles in disease development. The emerging field of epigenetics has provided new perspectives on the pathogenesis and development of autoimmune diseases. Aberrant epigenetic modifications can be used as biomarkers for disease diagnosis and prognosis. Exploration of human epigenetic profiles revealed that patients with autoimmune diseases exhibit markedly altered DNA methylation profiles compared with healthy individuals. Targeted cutting-edge epigenetic therapies are emerging. For example, DNA methylation inhibitors can rectify methylation dysregulation and relieve patients. Histone deacetylase inhibitors such as vorinostat can affect chromatin accessibility and further regulate gene expression, and have been used in treating hematological malignancies. Epigenetic therapies have opened new avenues for the precise treatment of autoimmune diseases and offer new opportunities for improved therapeutic outcomes. Our review can aid in comprehensively elucidation of the mechanisms of autoimmune diseases and development of new targeted therapies that ultimately benefit patients with these conditions.

IL-22, a vital cytokine in autoimmune diseases

Interleukin-22 (IL-22) is a vital cytokine that is dysregulated in various autoimmune conditions including rheumatoid arthritis (RA), multiple sclerosis (MS), and Alzheimer's disease (AD). As the starting point for the activation of numerous signaling pathways, IL-22 plays an important role in the initiation and development of autoimmune diseases. Specifically, imbalances in IL-22 signaling can interfere with other signaling pathways, causing cross-regulation of target genes which ultimately leads to the development of immune disorders. This review delineates the various connections between the IL-22 signaling pathway and autoimmune disease, focusing on the latest understanding of the cellular sources of IL-22 and its effects on various cell types. We further explore progress with pharmacological interventions related to targeting IL-22, describing how such therapeutic strategies promise to usher in a new era in the treatment of autoimmune disease.

Detection of decline in pulmonary function in patients with systemic sclerosis-associated interstitial lung disease using home monitoring in the Netherlands (DecreaSSc): a prospective, observational study

BACKGROUND

In patients with systemic sclerosis, interstitial lung disease (ILD) is the leading cause of mortality. Early detection of progressive ILD associated with systemic sclerosis is warranted for timely adjustment of management strategies and improved prognosis. We aimed to investigate the validity of home spirometry to detect a decline in pulmonary function in patients with systemic sclerosis-associated ILD.

METHODS

DecreaSSc was a prospective, observational study done in two tertiary referral centres in the Netherlands. Eligible patients were aged 18 years or older, fulfilled the American College of Rheumatology-European Alliance of Associations for Rheumatology criteria for systemic sclerosis, had a disease duration from first non-Raynaud phenomenon symptom of 5 years or less, had high-resolution CT-confirmed diagnosis of ILD, and had a maximum immunosuppressive treatment duration of 8 weeks at baseline. Patients took weekly home spirometry measurements using a handheld spirometer for 1 year. At baseline and at semi-annual study visits, patients pulmonary function testing was done in the hospital and patients completed questionnaires on patient-reported outcome measurements. The primary outcome was the κ agreement between home and hospital measurements after 1 year to detect a decline in force vital capacity (FVC) of 5% or more, estimated using separate linear regression analyses for home-based and hospital-based FVC% predicted in individual patients. The sensitivity and specificity of home spirometry to detect an absolute decline in FVC% predicted of 5% or more was assessed using the hospital pulmonary function test as the gold standard. The longitudinal correlation between hospital and home measurements was assessed with regression analysis, whereas the cross-sectional correlation was assessed with the intraclass coefficient. People with lived experience were involved at several stages of the study.

FINDINGS

Between Jan 26, 2021, and Feb 27, 2023, 43 patients were enrolled, 35 of whom completed 6 months of follow-up and 31 of whom completed 12 months of follow-up. The last follow-up visit took place on March 28, 2024. 20 (57%) of patients were women and 15 (43%) were men; 32 (91%) were White. Mean age was 57·7 years (SD 10·7). The agreement between hospital and home measurements had a κ value of 0·40 (95% CI 0·01-0·79). The sensitivity of home spirometry to detect a decline in FVC% predicted of 5% or more was 60% (95% CI 44-76) and specificity was 87% (75-98). Regression analysis showed that the course of pulmonary function was not different between hospital and home assessment as the interaction term was not significant (-0·0003 [95% CI -0·0006 to 0·000008]; p=0·057) with a longitudinal correlation of 0·55 (95% CI 0·26-0·74; p=0·0070). The intraclass coefficient between both measurements was 0·85 (95% CI 0·73-0·92; p<0·0001) at baseline, 0·84 (0·71-0·92; p<0·0001) at 6 months, and 0·72 (0·50-0·86; p<0·0001) at 12 months.

INTERPRETATION

Home spirometry has the potential to detect a decline in pulmonary function in patients with systemic sclerosis-associated ILD earlier when used in addition to regular health care management. Future research could reveal whether home spirometry can contribute to improved outcomes of patients with systemic sclerosis-associated ILD.

FUNDING

Galapagos and Boehringer Ingelheim.

Brain functional alternation in patients with systemic sclerosis: a resting-state functional magnetic resonance imaging study

BACKGROUND

Neuropsychiatric manifestations, such as cognitive impairment, are relatively prevalent in systemic sclerosis (SSc) patients. This study aimed to investigate the resting state (RS) functional alternations of SSc patients and the potential influenced factors.

METHODS

Forty-four SSc patients (mean age, 46.3 ± 11.4 years; 40 females) and 19 age and sex comparable healthy volunteers (mean age, 42.6 ± 11.3 years; 16 females) were recruited and underwent RS functional MR imaging (fMRI) and neuropsychological assessments. Functional segregation analysis was performed to calculate the amplitude of low frequency fluctuation (ALFF) and regional homogeneity (ReHo). Functional integration analysis was conducted using group independent component analysis to calculate intra-network and inter-network functional connectivity (FC). The fMRI measurements were compared between SSc patients and healthy volunteers using voxel-based pairwise two-sample t-tests. The correlations between clinical characteristics and fMRI measurements were also analyzed.

RESULTS

Compared to healthy volunteers, SSc patients exhibited significantly decreased ALFF and increased ReHo (all P < 0.01, FWE corrected). SSc patients predominantly showed decreased intra-network and inter-network FC in the auditory network, visual network, default mode network, frontoparietal network and attention network (intra-network FC: P < 0.01, uncorrected, cluster size > 30; inter-network FC: P < 0.05, FDR correction). Furthermore, clinical characteristics including disease duration (r value ranged from - 0.31 to 0.36), elevated erythrocyte sedimentation rate (r = 0.35), Montreal Cognitive Assessment score (r = 0.43), and Hamilton Depression Scale score (r = -0.40) were significantly associated with fMRI measurements (all P < 0.05).

CONCLUSIONS

Spontaneous activity and functional connectivity alternations can be seen in SSc patients, which are partially associated with neuropsychiatric manifestations and tend to aggravate with disease duration.

A Phase II study of avenciguat, a novel soluble guanylate cyclase activator, in patients with systemic sclerosis: Study design and rationale of the VITALISScE™ study

Introduction

Systemic sclerosis is a rare autoimmune connective tissue disease characterised by (1) microvasculopathy; (2) immune dysregulation; and (3) progressive fibrosis of the skin and internal organs. Soluble guanylate cyclase plays an important role in maintaining vascular and immunological homeostasis and preventing organ fibrosis. Pharmacological modulation of soluble guanylate cyclase with soluble guanylate cyclase stimulators has shown anti-inflammatory and antifibrotic effects in animal models of systemic sclerosis, with a trend towards clinical efficacy in a Phase II study (RISE-SSc). However, the efficacy of soluble guanylate cyclase stimulators may be reduced under conditions of hypoxia and oxidative stress. Soluble guanylate cyclase activators have the potential to overcome this limitation. This paper describes the study design of VITALISScE™, a Phase II clinical trial assessing the efficacy, safety and tolerability of avenciguat, a novel soluble guanylate cyclase activator in patients with active systemic sclerosis at risk of progression.

Methods

The VITALISScE™ study (NCT05559580) is evaluating the action of avenciguat on all three aspects of systemic sclerosis pathophysiology. The primary endpoint is the rate of decline in forced vital capacity (mL) over 48 weeks. Secondary endpoints include absolute change from baseline at Week 48 in modified Rodnan skin score, Health Assessment Questionnaire Disability Index score and the proportion of responders based on the revised Composite Response Index in Systemic Sclerosis. Additional endpoints include a composite assessment of Raynaud's phenomenon, digital ulcer burden, functional outcomes and quality of life, safety, pharmacokinetics, and biomarkers associated with systemic sclerosis and the mechanism of action of avenciguat.

Results

VITALISScE™ is an ongoing, multicentre (180 sites; 38 countries), placebo-controlled, double-blind, parallel-group, Phase II clinical study. Recruitment is currently ongoing.

Conclusions

The VITALISScE™ study is assessing the efficacy, safety and tolerability of avenciguat in patients with active systemic sclerosis at risk of progression. Results will inform further development of avenciguat.

Trial Registration

VITALISScE™; EU CT No. 2022-500332-11-00; Clinicaltrials.gov: NCT05559580 (https://www.clinicaltrials.gov/study/NCT05559580).

Barriers to CAR T-cell therapy in rheumatology

Chimeric antigen receptor (CAR) T cells have recently shown remarkable promise in treating rheumatic diseases, including systemic lupus erythematosus (SLE), idiopathic inflammatory myopathies, and systemic sclerosis. Currently, there are 37 clinical trials registered for CAR T-cell therapy in rheumatic diseases and many more are being planned. Much of this enthusiasm is justifiable, but widespread adoption of CAR T-cell therapy in rheumatology faces several barriers. The trajectory of autoimmune diseases differs from malignancies and a surprisingly narrow population could be eligible for CAR T-cell therapy. Current CAR T-cell approaches rely on B-cell depletion, which has a mixed record of success for many diseases. The high cost of CAR T-cell therapy and potential safety concerns, such as cytokine release syndrome and long-term infection risks, also pose substantial challenges. Moving forward, more targeted CAR T-cell approaches, such as antigen-specific chimeric autoantibody receptors or chimeric autoantigen T-cell receptors, could offer greater efficacy and safety in treating rheumatic diseases.

Chronic low-grade inflammation in patients with systemic sclerosis is associated with increased risk for arteriosclerotic cardiovascular disease

Background

Vasculopathy is a hallmark of systemic sclerosis (SSc) putting patients at an increased risk of cardiovascular disease. Approximately 20-25% of all SSc patients show prolonged elevated C-reactive protein (CRP) levels and thus signs of chronic low-grade inflammation. While CRP-positivity is an independent predictor of cardiovascular disease in non-SSc populations, the relationship between CRP-positivity and cardiovascular health/atherosclerosis in SSc patients is only incompletely understood. Here, we aimed to assess (1) which general, SSc disease-specific and cardiovascular parameters are associated with CRP-positivity in a cohort of SSc patients with prolonged CRP elevations (CRP+ SSc group) relative to SSc patients without CRP elevations (CRP- SSc group). In addition (2), we aimed to investigate whether prolonged CRP-positivity in SSc patients is associated with a higher cardiovascular risk and an increased atherosclerotic burden. We also aimed to (3) identify via random forest classification modeling which combined cardiovascular and/or SSc-specific parameters could differentiate best between SSc patients with elevated CRP levels (the so-called "inflammatory SSc subtype") and SSc patients without increased CRP levels.

Methods

Sixty-five SSc patients were recruited and assigned to the CRP+ SSc group (n = 20) if their CRP levels were > 5 mg/L in at least three half-yearly visits within 2 years before enrolment or to the CRP- SSc group (n = 45), respectively. All patients underwent an anamnesis, physical examination, blood draw, and bilateral carotid ultrasound in order to assess arteriosclerotic burden including the presence, number and height of plaques, and carotid intima-media thickness (CIMT) as well as lipid profiles. 10-year ASCVD risk was estimated via the ASCVD risk estimator plus. Statistical evaluation included Spearman's correlations, logistic regression and random forest modeling under 5-fold cross-validation, and permutation testing to determine combinations of cardiovascular variables highly discriminatory for CRP-positivity.

Results

SSc groups showed comparable mean age, height, and extent of SSc organ involvement. Regarding cardiovascular health, CRP+ SSc patients exhibited a significantly altered HDL-, LDL-, and triglyceride profile (0.001 ≤ p ≤ 0.017) and a significantly higher 10-year ASCVD risk (p = 0.047), relative to CRP- SSc patients. Additionally, within the subgroup of CRP+ SSc patients, positive correlations between CRP levels and CIMT right (ρ = 0.657, p = 0.002) and mean CIMT left and right (ρ = 0.497, p = 0.026) were seen. Combined ROC models identified the four lipid components (HDL, LDL, total cholesterol, and triglycerides) or the SSc duration and ASCVD category to differentiate with high cross-validated ROC-AUCs (AUC: 0.83 ± 0.15, and AUC: 0.86 ± 0.09, p < 0.001) for prolonged CRP-positivity among SSc patients.

Conclusion

Our data indicate that persistent CRP-positivity and thus chronic low-grade inflammation in SSc patients enhance the risk for arteriosclerotic-cardiovascular disease significantly beyond the ASCVD risk observed for our SSc patients without CRP elevations. It seems to be along with a disrupted lipid profile the hallmark of a distinct "inflammatory" subgroup of SSc patients. However, large population-based studies and clinical trials in patients with SSc are needed to validate our findings in a prospective or interventional setting.

Gut microbiome and metabolomics in systemic sclerosis: feature, link and mechanisms

Systemic sclerosis (SSc) is a rare and highly heterogeneous chronic autoimmune disease characterized by multi-organ and tissue fibrosis, often accompanied by a poor prognosis and high mortality rates. The primary pathogenic mechanisms of SSc are considered to involve tissue fibrosis, autoimmune dysfunction, and microvascular abnormalities. Recent studies have shed light on the gut microbiota (GM) and metabolites in SSc patients, revealing their association with gastrointestinal symptoms and disease phenotypes. However, further elucidation is needed on the specific mechanisms underlying the interactions between GM, metabolites, and the immune system and their roles in the pathogenesis of SSc. This review outlines the characteristics of GM and metabolites in SSc patients, exploring their interrelationships and analyzing their correlations with the clinical phenotypes of SSc. The findings indicate that while the α-diversity of GM in SSc patients resembles that of healthy individuals, notable differences exist in the β-diversity and the abundance of specific bacterial genera, which are closely linked to gastrointestinal symptoms. Moreover, alterations in the levels of amino acids and lipid metabolites in SSc patients are prominently observed and significantly associated with clinical phenotypes. Furthermore, this review delves into the potential immunopathological mechanisms of GM and metabolites in SSc, emphasizing the critical role of interactions between GM, metabolites, and the immune system in comprehending the immunopathological processes of SSc. These insights may offer new scientific evidence for the development of future treatment strategies.