Vasculopathy in scleroderma

Calcinosis Prevalence in Autoimmune Connective Tissue Diseases-A Retrospective Study

Background/Objectives: Calcinosis cutis is the deposition of insoluble calcium salts, which may cause inflammation, ulceration, pain, and restricted joint mobility. It rarely develops in damaged tissues (dystrophic subtype), most frequently in autoimmune connective tissue diseases (CTDs), but there is very limited data on the prevalence. Also, therapy remains an unsolved issue. In this study, we aimed to collect data on the prevalence of calcinosis in CTD patients to highlight that it is a considerable problem. Methods: A retrospective study was conducted in our department to assess the epidemiology of dystrophic calcinosis in CTDs between January 2003 and January 2024. Results: A total of 839 CTD patients were identified, of whom 56 had calcinosis (6.67%). The mean age of the calcinosis patients at diagnosis of underlying CTD was 41.16 ± 19.47 years. The mean time interval from the onset of calcinosis was 5.96 ± 8.62 years. Systemic sclerosis was the most common CTD complicated by calcinosis (n = 22). Conclusions: Our results are comparable to those reported previously in the literature. Although calcinosis is rare in the overall population, it is a present and unsolved problem in CTD patients. Therefore, further studies are needed on the factors involved in the development and progression of calcinosis as well as its treatment.

Single-cell transcriptomes and chromatin accessibility of endothelial cells unravel transcription factors associated with dysregulated angiogenesis in systemic sclerosis

OBJECTIVES

Vasculopathy emerges early in systemic sclerosis (SSc) and links to endothelial cell (EC) injury and angiogenesis. Understanding EC transcriptomes and epigenomes is crucial for unravelling the mechanisms involved.

METHODS

Transcriptomes and chromatin accessibility were assessed by single-cell RNA sequencing and single-nucleus transposase-accessible chromatin sequencing. Immunofluorescent staining of skin and proteomics assay were employed to confirm the altered SSc EC phenotypes. Gain-of-function assay was used to evaluate the effects of ETS transcription factors on human dermal ECs (hDECs).

RESULTS

Both control and SSc ECs shared transcriptomic signatures of vascular linages (arterial, capillary and venous ECs) and lymphatic ECs. Arterial ECs in SSc showed reduced number and increased expression of genes associated with apoptosis. Two distinct EC subpopulations, tip and proliferating ECs, were markedly upregulated in SSc, indicating enhanced proangiogenic and proliferative activities. Molecular features of aberrant SSc-ECs were associated with disease pathogenesis and clinical traits of SSc, such as skin fibrosis and digital ulcers. Ligand-receptor analysis demonstrated altered intercellular networks of SSc EC subpopulations with perivascular and immune cells. Furthermore, the integration of open chromatin profiles with transcriptomic analysis suggested an increased accessibility of regulatory elements for ETS family transcription factors in SSc ECs. Overexpression of ETS genes in hDECs suggested ELK4, ERF and ETS1 may orchestrate arterial apoptosis and dysregulated angiogenesis in SSc.

CONCLUSIONS

This study unveils transcriptional and chromatin alterations in driving endovascular dysregulation in SSc, proposing ELK4, ERF and ETS1 as novel targets in ECs for addressing vascular complications in the condition.

Immunogenetics of Systemic Sclerosis

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

Overlap syndrome of systemic sclerosis with antineutrophil cytoplasmic antibody-associated vasculitis according to 2022 ACR/EULAR criteria

BACKGROUND/AIMS

This study applied the 2022 American College of Rheumatology (ACR)/European Alliance of Associations for Rheumatology (EULAR) criteria for antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) to patients with systemic sclerosis (SSc) and investigated the frequency of overlap syndrome of SSc and AAV (SSc-AAV-OS).

METHODS

Among the 232 patients diagnosed with SSc, 105 with signs suggestive of small- or medium-vessel vasculitis, which were defined as the present of interstitial lung disease (ILD), peripheral neuropathy, or suspected renal vasculitis, were included in this study and analyzed.

RESULTS

Among the 105 SSc patients, the detection rate of ANCA was 19.0%. When the 2022 ACR/EULAR criteria were applied, the frequency of SSc-AAV-OS was 20.0%, which was much higher than 1.7% reported with previous criteria for AAV. ANCA positivity contributed to the reclassification of SSc-AAV-OS more than ANCA negativity in SSc patients with signs suggestive of small- or medium-vessel vasculitis.

CONCLUSION

The frequency of SSc-AAV-OS in SSc patients with signs suggestive of small- or medium-vessel vasculitis at diagnosis was 20.0%. Therefore, we suggest that physicians should perform ANCA tests in SSc patients exhibiting signs suggestive of small- or medium-vessel vasculitis and apply the new criteria for AAV.

Serum levels of AGGF1: Potential association with cutaneous and cardiopulmonary involvements in systemic sclerosis

Systemic sclerosis (SSc) is an autoimmune disease characterized by vasculopathy, aberrant immune activation, and extensive tissue fibrosis of the skin and internal organs. Because of the complicated nature of its pathogenesis, the underlying mechanisms of SSc remain incompletely understood. Angiogenic factor with a G-patch domain and a Forkhead-associated domain 1 (AGGF1) is a critical factor in angiogenesis expressed on vascular endothelial cells, associated with inflammatory and fibrotic responses. To elucidate the possible implication of AGGF1 in SSc pathogenesis, we investigated the association between serum AGGF1 levels and clinical manifestations in SSc patients. We conducted a cross-sectional analysis of AGGF1 levels in sera from 60 SSc patients and 19 healthy controls with enzyme-linked immunosorbent assay. Serum AGGF1 levels in SSc patients were significantly higher than those in healthy individuals. In particular, diffuse cutaneous SSc patients with shorter disease duration had higher levels compared to those with longer disease duration and limited cutaneous SSc patients. Patients with higher serum AGGF1 levels had a higher incidence of digital ulcers, higher modified Rodnan Skin Scores (mRSS), elevated serum Krebs von den Lungen-6 (KL-6) levels, C-reactive protein levels, and right ventricular systolic pressures (RVSP) on the echocardiogram, whereas they had reduced percentage of vital capacity (%VC) and percentage of diffusing capacity of the lungs for carbon monoxide (%DLCO) in pulmonary functional tests. In line, serum AGGF1 levels were significantly correlated with mRSS, serum KL-6 and surfactant protein D levels, RVSP, and %DLCO. These results uncovered notable correlations between serum AGGF1 levels and key cutaneous and vascular involvements in SSc, suggesting potential roles of AGGF1 in SSc pathogenesis.

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

Background

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

Methodology

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

Results

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

Discussion

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

Conclusion

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

Characterization of Vascular Niche in Systemic Sclerosis by Spatial Proteomics

BACKGROUND

Systemic sclerosis (SSc) is a connective tissue disease that can serve as a model to study vascular changes in response to inflammation, autoimmunity, and fibrotic remodeling. Although microvascular changes are the earliest histopathologic manifestation of SSc, the vascular pathophysiology remains poorly understood.

METHODS

We applied spatial proteomic approaches to deconvolute the heterogeneity of vascular cells at the single-cell level in situ and characterize cellular alterations of the vascular niches of patients with SSc. Skin biopsies of patients with SSc and control individuals were analyzed by imaging mass cytometry, yielding a total of 90 755 cells including 2987 endothelial cells and 4096 immune cells.

RESULTS

We identified 7 different subpopulations of blood vascular endothelial cells (VECs), 2 subpopulations of lymphatic endothelial cells, and 3 subpopulations of pericytes. A novel population of CD34+;αSMA+ (α-smooth muscle actin);CD31+ VECs was more common in SSc, whereas endothelial precursor cells were decreased. Co-detection by indexing and tyramide signal amplification confirmed these findings. The microenvironment of CD34+;αSMA+;CD31+ VECs was enriched for immune cells and myofibroblasts, and CD34+;αSMA+;CD31+ VECs expressed markers of endothelial-to-mesenchymal transition. The density of CD34+;αSMA+;CD31+ VECs was associated with clinical progression of fibrosis in SSc.

CONCLUSIONS

Using spatial proteomics, we unraveled the heterogeneity of vascular cells in control individuals and patients with SSc. We identified CD34+;αSMA+;CD31+ VECs as a novel endothelial cell population that is increased in patients with SSc, expresses markers for endothelial-to-mesenchymal transition, and is located in close proximity to immune cells and myofibroblasts. CD34+;αSMA+;CD31+ VEC counts were associated with clinical outcomes of progressive fibrotic remodeling, thus providing a novel cellular correlate for the crosstalk of vasculopathy and fibrosis.

Cardiovascular risk and inflammation in a population with autoimmune diseases: a narrative review

Juvenile Systemic Connective Tissue Diseases (JSCTD) are a heterogeneous group of chronic autoimmune diseases, associated with dyslipidemia and increased cardiovascular risk are related. Studies from the last 10 years, from 2013 to 2022, on lipid profiles in JSCTD were collected. Different studies on lipid profiles in children affected by JSCTD were selected, because the aim is to analyze the cardiovascular risk and the possibility of atherosclerosis in these patients in whom, sometimes, corticosteroid therapies and immunosuppressants increase the state of dyslipidemia. Several studies have shown that autoimmune diseases with an inflammatory substrate also share abnormalities in lipid profile and increased cardiovascular risk. Specifically, associations have been found between Juvenile Systemic Connective Tissue Diseases and elevated triglycerides, TC-C (Total Cholesterol), LDL-C (Low-Density Lipoprotein), low HDL-C (High-Density Lipoprotein), and increased risk of developing diseases such as myocardial infarction, peripheral vascular disease, pulmonary and arterial hypertension, and atrial fibrillation. Supplementation with alpha-linolenic acid (ALA) on the other hand has also been analyzed with positive results in reducing inflammatory parameters, such as IL-6 (Interleukin-6), CRP (C-reactive protein), and fasting glucose, in subjects with dyslipidemia. These observations suggest that supplementation with ALA, an omega-3 precursor, may positively modulate both the inflammatory status and dyslipidemic conditions in patients with autoimmune disorders.

Reliability and validity of the Turkish version of Scleroderma Skin Patient-Reported Outcome in patients with systemic sclerosis

Objectives

This study aimed to translate the Scleroderma Skin Patient-Reported Outcome (SSPRO) questionnaire to the Turkish (SSPRO-T) language and to assess its validity and reliability.

Patients and methods

Fifty-four systemic sclerosis (SSc) patients (51 females, 3 males; mean age: 49.8±10.4 years; range, 22 to 65 years) participated in the reliability and validity analysis between October 2022 and December 2022. The translation and cross-cultural adaptation of the SSPRO-T was applied in accordance with the procedure described by the Beaton guidelines. The SSPRO-T, the Scleroderma Health Assessment Questionnaire (SHAQ), the Health Assessment Questionnaire Disability Index (HAQ-DI), Skindex-29, and patient global skin severity were conducted in all participants for construct validity. The SSPRO-T was retested to assess its reliability after seven days.

Results

The SSPRO-T had a four-factor structure. The total SSPRO-T score and its subgroups correlated positively with SHAQ, HAQ-DI, Skindex-29, and patient global skin severity. The internal consistency and reliability were excellent in overall SSPRO-T and in the subgroups: physical effect, emotional effect, physical limitation, and social effect (Cronbach's α=0.94, 0.80, 0.95, 0.93, and 0.84, respectively). The SSPRO-T had excellent test-retest reliability (r=0.91, p<0.001). In addition, no floor effect or ceiling effect was observed.

Conclusion

The SSPRO-T questionnaire is a reliable and valid tool and can be used in research and clinical practice in Turkish patients with SSc.

Incidence of Systemic Vasculitis and Clinical Outcomes in Systemic Sclerosis: 2-Years Follow-Up of Asymptomatic Positive for Anti-Neutrophilic Cytoplasmic Antibody

Purpose

Anti-neutrophilic cytoplasmic antibody (ANCA)-associated vasculitis (AAV) overlap with systemic sclerosis (SSc) is uncommon. We aimed to determine the incidence of AAV and define clinical outcomes relevant to asymptomatic screening positive for ANCA in SSc after 2 years of follow-up.

Patients and Methods

The study was a cohort study of 185 Thai adult SSc patients testing for ANCA and having a 2-year follow-up at the Scleroderma Clinic, Khon Kaen University, Thailand. The incidence of AAV and outcomes of those who tested positive for ANCA were evaluated.

Results

A total of 185 SSc patients were tested for ANCA, of whom 21.6% were positive for either cytoplasmic ANCA, perinuclear ANCA (p-ANCA), anti-myeloperoxidase (anti-MPO), or anti-proteinase3 antibody. Only one 52-year-old female patient with dcSSc, negative for initial ANCA test, developed AAV (microscopic polyangiitis) 7 months after the first ANCA test for an incidence of AAV of 0.27 per 100-person-years (95% CI 0.01-1.5). She was positive for p-ANCA and anti-MPO. Eight of those who had an initial test were positive for ANCA and underwent a repeated test. Only two cases persisted as positive for ANCA (1 anti-MPO and 1 anti-PR3) and had no clinicals suspicious of vasculitis. Four cases that had ANCA turned to a negative result.

Conclusion

AAV is a rare complication in SSc, so ANCA may not have any role as a screening test for AAV as it cannot predict the development of AAV in SSc. We suggest testing for ANCA only in SSc patients with clinicals suspicious of AAV.

The Association of Telangiectasias with Other Peripheral Vascular Lesions of Systemic Sclerosis

Purpose

Systemic sclerosis (SSc) is a relatively rare collagenosis manifested as microvasculopathy, excessive cutaneous and visceral fibrosis in a background of autoimmune alteration. Autoimmune vasculopathy in SSc occurs early and begins with endothelial cell activation followed by blood vessel intimal proliferation in a context of defective angiogenesis. The alteration of peripheral micro and macrocirculation in SSc is evident through vascular lesions, such as Raynaud's phenomenon, telangiectasias, acrocyanosis, digital ulcers, gangrene, peripheral pulse deficiency. Our paper details the results of the study on the association between telangiectasias and other types of immune-mediated peripheral vascular lesions that can be identified in SSc. The presence of these peripheral vascular lesions can provide information about the magnitude of the peripheral vasculopathy.

Patients and Methods

A total of 37 patients diagnosed with SSc, recruited from a university clinic in Bucharest between February 2019 and March 2020, were enrolled in an observational study. We evaluated the presence of telangiectasias, as a stigma of autoimmune microvasculopathy, and their association with other immune-mediated peripheral vascular lesions that may be present in SSc.

Results

The presence of telangiectasias was identified in the absence, but especially in the presence of acrocyanosis and digital ulcerations, and patients with peripheral pulse deficiency almost always had telangiectasias. Less than a quarter of the patients with digital ulcers progressed unfavorably to gangrene, and only one required amputation, telangiectasias being present not only in the patient with amputation but in all patients with gangrene.

Conclusion

We appreciate that telangiectasias may be the clinical expression of peripheral vasculopathy characteristic of SSc, they can often be present in association with other peripheral vascular lesions and may represent a valuable indicator for the gangrene risk of digital ulcerations in SSc.

Systems-based identification of the Hippo pathway for promoting fibrotic mesenchymal differentiation in systemic sclerosis

Systemic sclerosis (SSc) is a devastating autoimmune disease characterized by excessive production and accumulation of extracellular matrix, leading to fibrosis of skin and other internal organs. However, the main cellular participants in SSc skin fibrosis remain incompletely understood. Here using differentiation trajectories at a single cell level, we demonstrate a dual source of extracellular matrix deposition in SSc skin from both myofibroblasts and endothelial-to-mesenchymal-transitioning cells (EndoMT). We further define a central role of Hippo pathway effectors in differentiation and homeostasis of myofibroblast and EndoMT, respectively, and show that myofibroblasts and EndoMTs function as central communication hubs that drive key pro-fibrotic signaling pathways in SSc. Together, our data help characterize myofibroblast differentiation and EndoMT phenotypes in SSc skin, and hint that modulation of the Hippo pathway may contribute in reversing the pro-fibrotic phenotypes in myofibroblasts and EndoMTs.

Nailfold videocapillaroscopy in antineutrophil cytoplasmic antibody-associated vasculitis

OBJECTIVE

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a group of illnesses that cause inflammation and alterations to small vessels in the body. Some of the most common and detrimental manifestations, including alveolar hemorrhage and glomerulonephritis, are caused by this capillary inflammation. We sought to clarify whether patients with AAV would have abnormal nailfold capillaries when evaluated with nailfold videocapillaroscopy.

METHODS

Patients with a current diagnosis of AAV and a control group were identified for enrollment. Nailfold videocapillaroscopy images were used for a semiquantitative analysis on capillary density, morphology, dilation, and microhemorrhage after review by 2 rheumatologists. Disease characteristics, occurrence of recent disease flare, and presence of ANCA were recorded.

RESULTS

Thirty-three patients with a diagnosis of AAV and 21 controls were recruited. The AAV group had a median age of 59 and 17 (52%) were women. Granulomatosis with polyangiitis was the most common diagnosis (19 [58%]), followed by eosinophilic granulomatosis with polyangiitis (7 [21%]) and microscopic polyangiitis (7 [21%]). Twenty-seven patients (82%) had positive ANCA tests. After assessment of capillary density, dilation, morphology, microhemorrhages, and disorganization, there were no statistically significant differences between the 2 groups.

CONCLUSION

There was no evidence of differences in nailfold capillaroscopy abnormalities between those diagnosed with AAV and the control group. While this cohort was relatively small, we did not find a high enough prevalence or specific phenotype of capillary abnormalities that could aid in diagnosis or prognostication of these diseases in the clinical setting.

Treatable Traits in Systemic Sclerosis

Systemic sclerosis (SSc) is a chronic systemic disease within the spectrum of connective tissue diseases, specifically characterized by vascular abnormalities and inflammatory and fibrotic involvement of the skin and internal organs resulting in high morbidity and mortality. The clinical phenotype of SSc is heterogeneous, and serum autoantibodies together with the extent of skin involvement have a predictive value in the risk stratification. Current recommendations include an organ-based management according to the predominant involvement with only limited individual factors included in the treatment algorithm. Similar to what has been proposed for other chronic diseases, we hypothesize that a "treatable trait" approach based on relevant phenotypes and endotypes could address the unmet needs in SSc stratification and treatment to maximize the outcomes. We provide herein a comprehensive review and a critical discussion of the literature regarding potential treatable traits in SSc, focusing on established and candidate biomarkers, with the purpose of setting the bases for a precision medicine-based approach. The discussion, structured based on the organ involvement, allows to conjugate the pathogenetic mechanisms of tissue injury with the proposed predictors, particularly autoantibodies and other serum biomarkers. Ultimately, we are convinced that precision medicine is the ideal guide to manage a complex condition such as SSc for which available treatments are largely unsatisfactory.

The Pathogenesis of Systemic Sclerosis: The Origin of Fibrosis and Interlink with Vasculopathy and Autoimmunity

Systemic sclerosis (SSc) is an autoimmune disease associated with increased mortality and poor morbidity, impairing the quality of life in patients. Whilst we know that SSc affects multiple organs via vasculopathy, inflammation, and fibrosis, its exact pathophysiology remains elusive. Microvascular injury and vasculopathy are the initial pathological features of the disease. Clinically, the vasculopathy in SSc is manifested as Raynaud's phenomenon (reversible vasospasm in reaction to the cold or emotional stress) and digital ulcers due to ischemic injury. There are several reports that medications for vasculopathy, such as bosentan and soluble guanylate cyclase (sGC) modulators, improve not only vasculopathy but also dermal fibrosis, suggesting that vasculopathy is important in SSc. Although vasculopathy is an important initial step of the pathogenesis for SSc, it is still unclear how vasculopathy is related to inflammation and fibrosis. In this review, we focused on the clinical evidence for vasculopathy, the major cellular players for the pathogenesis, including pericytes, adipocytes, endothelial cells (ECs), and myofibroblasts, and their signaling pathway to elucidate the relationship among vasculopathy, inflammation, and fibrosis in SSc.

GRB2 serves as a viable target against skin fibrosis in systemic sclerosis by regulating endothelial cell apoptosis

BACKGROUND

Systemic Sclerosis (SSc) is an autoimmune disease characterized by vascular and immune system dysfunction, along with tissue fibrosis. Our previous study found GRB2 was downregulated by salvianolic acid B, a small molecule drug that attenuated skin fibrosis of SSc.

OBJECTIVES

Here we aim to investigate the role of GRB2 in SSc.

METHODS

The microarray data of SSc skin biopsies in Caucasians were obtained from the Gene Expression Omnibus (GEO) database. The expression of GRB2 was further detected in Chinese SSc and healthy controls. Bleomycin (BLM)-induced skin fibrosis mice were used to explore how GRB2 downregulation affected fibrosis. The apoptosis of EA.hy926 endothelial cells was induced by H2O2 and apoptosis ratio was measured by flow cytometric. Transcriptome and phosphoproteomic analyses were performed to explore the regulated pathway.

RESULTS

The expression of GRB2 was significantly enhanced in SSc patient skin, 1.51-fold in Caucasians and 1.40-fold in Chinese. Double immunofluorescence staining showed the endothelial cells of SSc patient's skin highly expressed GRB2. The in vivo study revealed that GRB2 knockdown alleviated skin fibrosis and apoptosis of endothelial cells in BLM mouse skin. The in vitro study showed that GRB2 downregulation inhibited the apoptosis of EA.hy926 and protected them from H2O2-induced hyperpermeability. Moreover, transcriptome and phosphoproteomic analysis suggested the focal adhesion pathway was enriched in GRB2 siRNA transfected endothelial cells.

CONCLUSIONS

Our results demonstrated GRB2 highly expressed in endothelial cells of SSc skin, and inhibiting GRB2 could effectively attenuate BLM-induced skin fibrosis and endothelial cell apoptosis. GRB2 is expected to be a new therapeutic target for SSc.

Research progress on mesenchymal stem cells and their exosomes in systemic sclerosis

Systemic sclerosis (SSc) is a connective tissue disease with an unknown etiology. Clinically, it is characterized by localized or diffuse skin thickening and fibrosis. The pathogenesis of SSc includes microvascular injury, autoimmune-mediated inflammation, and fibroblast activation. These processes interact and contribute to the diverse clinicopathology and presentation of SSc. Given the limited effectiveness and substantial side effects of traditional treatments, the treatment strategy for SSc has several disadvantages. Mesenchymal stem cells (MSCs) are expected to serve as effective treatment options owing to their significant immunomodulatory, antifibrotic, and pro-angiogenic effects. Exosomes, secreted by MSCs via paracrine signaling, mirror the effect of MSCs as well as offer the benefit of targeted delivery, minimal immunogenicity, robust reparability, good safety and stability, and easy storage and transport. This enables them to circumvent the limitations of the MSCs. When using exosomes, it is crucial to consider preparation methods, quality standards, and suitable drug delivery systems, among other technical issues. Therefore, this review aims to summarize the latest research progress on MSCs and exosomes in SSc, offering novel ideas for treating SSc.

Novel Therapeutic Strategies in the Treatment of Systemic Sclerosis

Systemic sclerosis is a connective tissue disease of unknown origin and with an unpredictable course, with both cutaneous and internal organ manifestations. Despite the enormous progress in rheumatology and clinical immunology, the background of this disease is largely unknown, and no specific therapy exists. The therapeutic approach aims to treat and preserve the function of internal organs, and this approach is commonly referred to as organ-based treatment. However, in modern times, data from other branches of medicine may offer insight into how to treat disease-related complications, making it possible to find new drugs to treat this disease. In this review, we present therapeutic options aiming to stop the progression of fibrotic processes, restore the aberrant immune response, stop improper signalling from proinflammatory cytokines, and halt the production of disease-related autoantibodies.

Single-Cell Analysis of ADSC Interactions with Fibroblasts and Endothelial Cells in Scleroderma Skin

Adipose-derived stem cells (ADSCs) as part of autologous fat grafting have anti-fibrotic and anti-inflammatory effects, but the exact mechanisms of action remain unknown. By simulating the interaction of ADSCs with fibroblasts and endothelial cells (EC) from scleroderma (SSc) skin in silico, we aim to unravel these mechanisms. Publicly available single-cell RNA sequencing data from the stromal vascular fraction of 3 lean patients and biopsies from the skin of 10 control and 12 patients with SSc were obtained from the GEO and analysed using R and Seurat. Differentially expressed genes were used to compare the fibroblast and EC transcriptome between controls and SSc. GO and KEGG functional enrichment was performed. Ligand-receptor interactions of ADSCs with fibroblasts and ECs were explored with LIANA. Pro-inflammatory and extracellular matrix (ECM) interacting fibroblasts were identified in SSc. Arterial, capillary, venous and lymphatic ECs showed a pro-fibrotic and pro-inflammatory transcriptome. Most interactions with both cell types were based on ECM proteins. Differential interactions identified included NTN1, VEGFD, MMP2, FGF2, and FNDC5. The ADSC secretome may disrupt vascular and perivascular inflammation hubs in scleroderma by promoting angiogenesis and especially lymphangiogenesis. Key phenomena observed after fat grafting remain unexplained, including modulation of fibroblast behaviour.

When natural antibodies become pathogenic: autoantibodies targeted against G protein-coupled receptors in the pathogenesis of systemic sclerosis

Systemic sclerosis (SSc) is a chronic, multisystem connective tissue, and autoimmune disease with the highest case-specific mortality and complications among rheumatic diseases. It is characterized by complex and variable features such as autoimmunity and inflammation, vasculopathy, and fibrosis, which pose challenges in understanding the pathogenesis of the disease. Among the large variety of autoantibodies (Abs) present in the sera of patients suffering from SSc, functionally active Abs against G protein-coupled receptors (GPCRs), the most abundant integral membrane proteins, have drawn much attention over the last decades. These Abs play an essential role in regulating the immune system, and their functions are dysregulated in diverse pathological conditions. Emerging evidence indicates that functional Abs targeting GPCRs, such as angiotensin II type 1 receptor (AT1R) and the endothelin-1 type A receptor (ETAR), are altered in SSc. These Abs are part of a network with several GPCR Abs, such as those directed to the chemokine receptors or coagulative thrombin receptors. In this review, we summarize the effects of Abs against GPCRs in SSc pathologies. Extending the knowledge on pathophysiological roles of Abs against GPCRs could provide insights into a better understanding of GPCR contribution to SSc pathogenesis and therefore help in developing potential therapeutic strategies that intervene with pathological functions of these receptors.

M2 macrophage polarization in systemic sclerosis fibrosis: pathogenic mechanisms and therapeutic effects

Systemic sclerosis (SSc, scleroderma), is an autoimmune rheumatic disease characterized by fibrosis of the skin and internal organs, and vasculopathy. Preventing fibrosis by targeting aberrant immune cells that drive extracellular matrix (ECM) over-deposition is a promising therapeutic strategy for SSc. Previous research suggests that M2 macrophages play an essential part in the fibrotic process of SSc. Targeted modulation of molecules that influence M2 macrophage polarization, or M2 macrophages, may hinder the progression of fibrosis. Here, in an effort to offer fresh perspectives on the management of scleroderma and fibrotic diseases, we review the molecular mechanisms underlying the regulation of M2 macrophage polarization in SSc-related organ fibrosis, potential inhibitors targeting M2 macrophages, and the mechanisms by which M2 macrophages participate in fibrosis.

Additional value of T1 and T2 mapping techniques for early detection of myocardial involvement in scleroderma

BACKGROUND

We evaluated the prevalence of myocardial involvement by native T1 and T2 mapping, the diagnostic performance of mapping in addition to conventional Lake Louise Criteria (LLC), as well as correlations between mapping findings and clinical or conventional cardiovascular magnetic resonance (CMR) parameters in systemic sclerosis (SSc) patients.

METHODS

Fifty-five SSc patients (52.31 ± 13.24 years, 81.8% female) and 55 age- and sex-matched healthy subjects underwent clinical, bio-humoral assessment, and CMR. The imaging protocol included: T2-weighted, early post-contrast cine sequences, native T1 and T2 mapping by a segmental approach, and late gadolinium enhancement (LGE) technique.

RESULTS

Global myocardial T1 and T2 values were significantly higher in SSc patients than in healthy subjects. An increase in native T1 and/or T2 was present in the 62.1% of patients with normal conventional CMR techniques (negative LGE and T2-weighted images). Respectively, 13.5% and 59.6% of patients fulfilled original and updated LLC (overall agreement = 53.9%). Compared with patients with normal native T1, patients with increased T1 (40.0%) featured significantly higher left ventricular end-diastolic volume index and cardiac index, biventricular stroke volume indexes, and global heart T2 values, and more frequently had a history of digital ulcers. Biochemical and functional CMR parameters were comparable between patients with normal and increased T2 (61.8%).

CONCLUSION

T1 and T2 mapping are sensitive parameters that should be included in the routine clinical assessment of SSc patients for detecting early/subclinical myocardial involvement.

Prevalence of and factors independently associated with digital ischemic complications in patients with systemic sclerosis

Objective

To investigate the prevalence of and independent predictors for digital ischemic complications in patients with systemic sclerosis.

Method

Patients enrolled in the Siriraj Systemic Sclerosis Cohort registry during 2013-2019 were classified as having or not having digital ischemic complications at the baseline and 1-year timepoints.

Results

A total of 171 patients with systemic sclerosis were included. The prevalence of digital pulp loss, digital pitting scar, digital ulcer, and digital amputation at baseline and 1 year was 41.5%, 39.8%, 3.5%, 7.6% and 37.4%, 43.9%, 14.1%, 6.4%, respectively. Over half (58.5%) of overall systemic sclerosis had developed new digital ischemic complications during the 1-year follow-up. Those with digital ischemic complications at baseline were at high risk for developing new digital ischemic complications (odds ratio: 15.9). Diffuse cutaneous systemic sclerosis is associated with digital ischemic complications (odds ratio: 6.0), digital pitting scar (odds ratio: 4.9), and digital pulp loss (odds ratio: 6.4). Tendon friction rub is associated with digital pitting scar (odds ratio: 5.0). Salt-and-pepper skin appearance is associated with digital pulp loss (odds ratio: 3.0) and digital ulcer (odds ratio: 6.9). Disease duration > 3 years is associated with digital ulcer (odds ratio: 4.4). Male gender is associated with digital ulcer (odds ratio: 5.4).

Conclusion

Digital pulp loss, digital pitting scar, digital ulcer, and digital amputation were common manifestations of digital ischemic complications, and diffuse cutaneous systemic sclerosis was the strongest of the six independent predictors.

Proteomic aptamer analysis reveals serum markers that characterize preclinical systemic sclerosis (SSc) patients at risk for progression toward definite SSc

BACKGROUND

The study of molecular mechanisms characterizing disease progression may be relevant to get insights into systemic sclerosis (SSc) pathogenesis and to intercept patients at very early stage. We aimed at investigating the proteomic profile of preclinical systemic sclerosis (PreSSc) via a discovery/validation two-step approach.

METHODS

SOMAcan aptamer-based analysis was performed on a serum sample of 13 PreSSc (discovery cohort) according to 2001 LeRoy and Medsger criteria (characterized solely by Raynaud phenomenon plus a positive nailfold capillaroscopy and SSc-specific antibodies without any other sign of definite disease) and 8 healthy controls (HCs) age, gender, and ethnicity matched. Prospective data were available up to 4±0.6 years to determine the progression to definite SSc according to the EULAR/ACR 2013 classification criteria. In proteins with relative fluorescence units (RFU) > |1.5|-fold vs HCs values, univariate analysis was conducted via bootstrap aggregating models to determine the predicting accuracy (progression vs non-progression) of categorized baseline protein values. Gene Ontologies (GO terms) and Reactome terms of significant proteins at the adjusted 0.05 threshold were explored. Significant proteins from the discovery cohort were finally validated via ELISAs in an independent validation cohort of 50 PreSSc with clinical prospective data up to 5 years. Time-to-event analysis for interval-censored data was used to evaluate disease progression.

RESULTS

In the discovery cohort, 286 out of 1306 proteins analyzed via SomaScan, were differentially expressed versus HCs. Ten proteins were significantly associated with disease progression; analysis through GO and Reactome showed differentially enriched pathways involving angiogenesis, endothelial cell chemotaxis, and endothelial cell chemotaxis to fibroblast growth factor (FGF). In the validation cohort, endostatin (HR=10.23, CI95=2.2-47.59, p=0.003) was strongly associated with disease progression, as well as bFGF (HR=0.84, CI95=0.709-0.996, p=0.045) and PAF-AHβ (HR=0.372, CI95=0.171-0.809, p=0.013) CONCLUSIONS: A distinct protein profile characterized PreSSc from HCs and proteins associated with hypoxia, vasculopathy, and fibrosis regulation are linked with the progression from preclinical to definite SSc. These proteins, in particular endostatin, can be regarded both as markers of severity and molecules with pathogenetic significance as well as therapeutic targets.

Extensive and Persistent Extravascular Dermal Fibrin Deposition Characterizes Systemic Sclerosis

Systemic sclerosis (SSc) is an autoimmune disease characterized by progressive multiorgan fibrosis. While the cause of SSc remains unknown, a perturbed vasculature is considered a critical early step in the pathogenesis. Using fibrinogen as a marker of vascular leakage, we found extensive extravascular fibrinogen deposition in the dermis of both limited and diffuse systemic sclerosis disease, and it was present in both early and late-stage patients. Based on a timed series of excision wounds, retention on the fibrin deposit of the splice variant domain, fibrinogen αEC, indicated a recent event, while fibrin networks lacking the αEC domain were older. Application of this timing tool to SSc revealed considerable heterogeneity in αEC domain distribution providing unique insight into disease activity. Intriguingly, the fibrinogen-αEC domain also accumulated in macrophages. These observations indicate that systemic sclerosis is characterized by ongoing vascular leakage resulting in extensive interstitial fibrin deposition that is either continually replenished and/or there is impaired fibrin clearance. Unresolved fibrin deposition might then incite chronic tissue remodeling.

Association between oxygen delivery and digital ulcers in systemic sclerosis

OBJECTIVE

Tissue hypoxia due to microvasculopathy is the main cause of digital ulcers (DUs) in systemic sclerosis (SSc). Reduced oxygen delivery (DO2) to the tissues may also contribute to the development of DU. This study was conducted to investigate the association between DO2 and DUs in patients with SSc.

METHODS

In all, 111 patients and 30 healthy controls were enrolled. DO2 was calculated by using the formula; DO2 = Cardiac output × arterial oxygen saturation (SpO2) × serum haemoglobin level × 1.39 × 10. Both right index finger SpO2 measurements (index-SpO2) and highest value of SpO2 (maximum SpO2) obtained among the fingers of the subjects were used for the calculations and DO2 results were adjusted both for weight and body surface area (BSA).

RESULTS

Mean DO2 was lower in SSc patients as compared to controls in all 4 different calculations but the difference was only statistically significant when using index-SpO2 and adjusting for BSA (498 mL/min/m² vs 549 mL/min/m², p = 0.03). There was a strong positive correlation between cardiac output and DO2 calculated by using the index-SpO2 (r = 0.903; p < 0.001). Of the SSc patients, 46 (41.4 %) had DUs within the last 12 months. Patients with DUs had higher mean mRSS, lover mean FVC and more frequently diffuse disease, interstitial lung disease, anti-SCL70 antibody positivity (p < 0.05 for all). No difference was observed in DO2 among DU positive or DU negative groups by any calculation (p > 0.05 for all).

CONCLUSIONS

DO2 in SSc patients seems to be lower than healthy controls. However, DO2 is similar between the patients with and without DUs. Our results suggest that the contribution of DO2 is negligible to the development of DU and support the major role of microvasculopathy in SSc patients with DUs.

Wenyang Huazhuo Tongluo formula alleviates pulmonary vascular injury and downregulates HIF-1α in bleomycin-induced systemic sclerosis mouse model

Background

Vascular damage, autoimmune abnormalities, and fibrosis are the three pathological features of systemic sclerosis (SSc).However, pulmonary vascular damage is the main factor affecting the progression and prognosis of SSc. The main purpose of this study was to explore the molecular mechanism of Wenyang Huazhuo Tongluo Formula in alleviating pulmonary vascular injury in bleomycin-induced SSc mouse model.

Methods

Masson staining and H&E staining were used to analyze the degree of pulmonary vascular fibrosis and the infiltration of leukocyte cells in lung tissue ofbleomycin-induced SSc mouse models treated with saline (BLM group), Wenyang Huazhuo Tongluo Formula (WYHZTL group) and HIF-1α inhibitor KC7F2 (KC7F2 group). Blood vessel exudation was determined by analyzing the cell number and albumin concentration in bronchoalveolar lavage fluid using a cell counter and ELISA assay, respectively. The degree of vascular injury was assessed by measuring the expression levels of vWF, E-selectin, ICAM-1, VCAM-1, VE-cadherin and claudin-5 in serum and pulmonary vascular endothelial cells using ELISA and immunofluorescence staining. Finally, the effect of Wenyang Huazhuo Tongluo Formula on the expression of HIF-1α was detected using immunofluorescence staining.

Results

Wenyang Huazhuo Tongluo Formula and KC7F2 significantly inhibited bleomycin-induced pulmonary vascular fibrosis and the level of perivascular inflammatory cell infiltration. The number of cells and the concentration of albumin were significantly reduced in the bronchoalveolar lavage fluid of the WYHZTL group and KC7F2 group compared with the BLM group. In addition, treatment with Wenyang Huazhuo Tongluo Formula and KC7F2 significantly downregulated the expression levels of vWF, E-selectin, ICAM-1, VCAM-1 and HIF-1α, but upregulated the expression of VE-cadherin and claudin-5 in serum and pulmonary vascular endothelial cells, compared with treatment with saline.

Conclusions

This study reveals that Wenyang Huazhuo Tongluo Formula plays a new role in the treatment of SSc by alleviating pulmonary vascular damage. Furthermore, we found that Wenyang Huazhuo Tongluo Formula alleviates pulmonary vascular injury and inhibits HIF-1α expression.

Role of NLRP3 inflammasome in systemic sclerosis

Systemic sclerosis (SSc) is an autoimmune rheumatic disease with high mortality, which is featured by inflammation, vascular damage, and aggressive fibrosis. To date, the pathogenesis of SSc remains unclear and effective treatments are still under research. Active NLRP3 recruits downstream proteins such as ASC and caspase-1 and assembles into inflammasome, resulting in excretion of inflammatory cytokines including IL-1β and IL-18, as well as in pyroptosis mediated by gasdermin D. Various studies demonstrated that NLRP3 inflammasome might be involved in the mechanism of tenosynovitis, arthritis, fibrosis, and vascular damage. The pathophysiological changes might be due to the activation of proinflammatory Th2 cells, profibrotic M2 macrophages, B cells, fibroblasts, and endothelial cells. Here, we review the studies focused on NLRP3 inflammasome activation, its association with innate and adaptive immune cells, endothelium injury, and differentiation of fibroblasts in SSc. Furthermore, we summarize the prospect of therapy targeting NLRP3 pathway.

Cross-tissue, single-cell stromal atlas identifies shared pathological fibroblast phenotypes in four chronic inflammatory diseases

BACKGROUND

Pro-inflammatory fibroblasts are critical for pathogenesis in rheumatoid arthritis, inflammatory bowel disease, interstitial lung disease, and Sjögren's syndrome and represent a novel therapeutic target for chronic inflammatory disease. However, the heterogeneity of fibroblast phenotypes, exacerbated by the lack of a common cross-tissue taxonomy, has limited our understanding of which pathways are shared by multiple diseases.

METHODS

We profiled fibroblasts derived from inflamed and non-inflamed synovium, intestine, lungs, and salivary glands from affected individuals with single-cell RNA sequencing. We integrated all fibroblasts into a multi-tissue atlas to characterize shared and tissue-specific phenotypes.

FINDINGS

Two shared clusters, CXCL10+CCL19+ immune-interacting and SPARC+COL3A1+ vascular-interacting fibroblasts, were expanded in all inflamed tissues and mapped to dermal analogs in a public atopic dermatitis atlas. We confirmed these human pro-inflammatory fibroblasts in animal models of lung, joint, and intestinal inflammation.

CONCLUSIONS

This work represents a thorough investigation into fibroblasts across organ systems, individual donors, and disease states that reveals shared pathogenic activation states across four chronic inflammatory diseases.

FUNDING

Grant from F. Hoffmann-La Roche (Roche) AG.

Lung-kidney interactions and their role in chronic kidney disease-associated pulmonary diseases

Chronic illnesses rarely present in a vacuum, devoid of other complications, and chronic kidney disease is hardly an exception. Comorbidities associated with chronic kidney disease lead to faster disease progression, expedited dialysis dependency, and a higher mortality rate. Although chronic kidney disease is most commonly accompanied by cardiovascular diseases and diabetes, there is clear cross talk between the lungs and kidneys pH balance, phosphate metabolism, and immune system regulation. Our present understanding of the exact underlying mechanisms that contribute to chronic kidney disease-related pulmonary disease is poor. This review summarizes the current research on kidney-pulmonary interorgan cross talk in the context of chronic kidney disease, highlighting various acute and chronic pulmonary diseases that lead to further complications in patient care. Treatment options for patients presenting with chronic kidney disease and lung disease are explored by assessing activated molecular pathways and the body's compensatory response mechanisms following homeostatic imbalance. Understanding the link between the lungs and kidneys will potentially improve health outcomes for patients and guide healthcare professionals to better understand how and when to treat each of the pulmonary comorbidities that can present with chronic kidney disease.

Angiogenic T Cells: Potential Biomarkers for the Early Diagnosis of Interstitial Lung Disease in Autoimmune Diseases?

(1) Background: We explored, for the first time, the contribution of angiogenic T cells (TAng) in interstitial lung disease associated to autoimmune disease (AD-ILD+) as potential biomarkers of the disease, evaluating their role in the underlying vasculopathy and lung fibrosis. Additionally, the relationship of TAng with clinical manifestations and cellular and molecular endothelial dysfunction-related biomarkers was assessed. (2) Methods: We included 57 AD-ILD+ patients (21 with rheumatoid arthritis (RA)-ILD+, 21 with systemic sclerosis (SSc)-ILD+ and 15 with other AD-ILD+) and three comparative groups: 45 AD-ILD− patients (25 RA-ILD− and 20 SSc-ILD−); 21 idiopathic pulmonary fibrosis (IPF) patients; 21 healthy controls (HC). TAng were considered as CD3+CD184+CD31+ by flow cytometry. (3) Results: A similar TAng frequency was found between AD-ILD+ and IPF, being in both cases lower than that observed in AD-ILD− and HC. A lower TAng frequency was associated with negative Scl-70 status and lower FEV1/FVC ratio in SSc-ILD+, as well as with men in RA-ILD+ and non-specific interstitial pneumonia radiological pattern in other AD-ILD+. No relationship between TAng and endothelial progenitor cells, endothelial cells and vascular endothelial growth factor gene expression and protein levels was disclosed. (4) Conclusions: Our findings suggest TAng as potential biomarkers for the early diagnosis of ILD in AD.

Impaired fibrinolysis is linked with digital vasculopathy and onset of new digital ulcers in systemic sclerosis

Objective

To assess thrombin generation, fibrin formation and structure together with the fibrinolytic status in patients with systemic sclerosis (SSc) in relation to the occurrence of digital ulcers (DUs) during the course of disease.

Methods

We studied parameters of endothelial dysfunction, thrombin generation, overall haemostatic potential and fibrin clot turbidity in plasma from 58 SSc patients (39 with DUs history and 19 DU naïve) and 46 matched healthy controls (HC). Fibrin structure was visualised using scanning electron microscopy (SEM). Finally, 39 patients with a history of DUs were followed for 1.5 years and the predictive value of all investigated markers for new DU onset was explored.

Results

Significantly enhanced endogenous thrombin potential (ETP) and prolonged clot lysis time (CLT) were found in patients with DUs compared to HC. CLT was prolonged in patients with DUs compared to those without, showing good validity in identifying DUs with an area under the curve of 0.7, 95% CI 0.6-0.8. The levels of ETP and Intercellular Adhesion Molecule (ICAM1) were independently associated with CLT. Over the follow-up period, 20 patients developed new DU. CLT was prolonged (p<0.001) in patients with new DU episodes, especially those with recurrent DUs. Regression analysis showed that VAS Raynaud and CLT were predictors of new DUs (OR 1.1, 95%CI1.02-1.1; OR 1.2, 95%CI1.1-1.3, respectively. SEM confirmed denser fibrin clots in patients with new DUs.

Conclusion

Our results implicate that impaired fibrinolysis might have an emerged role in the underlying digital vasculopathy and its progression in SSc.

Clinical Relevance of Liver Involvement in the Clinical Course of Systemic Sclerosis

Liver involvement in systemic sclerosis (SSc) is rare. We evaluated the prevalence of liver fibrosis and hepatic autoimmunity in SSc patients in a retrospective observational cohort (97 SSc or mixed connective tissue disease with sclerodermic manifestations patients undergoing transient elastography, evaluating liver stiffness (LS) and controlled attenuation parameter (CAP), due to clinical indications along with biochemistry assessments and major antibodies associated to liver autoimmunity). Among them, 11 had LS ≥ 7.5 kPa and 5 showed an LS compatible with cirrhosis (LS ≥ 12.5 kPa). Predictors of LS ≥ 7.5 fibrosis were alcohol consumption (>14 or >7 alcoholic units/week for men and women, respectively), waist circumference (>102 or >88 cm for men and women, respectively), elevated alkaline phosphatase, and anti-La and anti-mitochondrial antibody (AMA) positivity. Six patients had CAP values compatible with severe steatosis (≥280 dB/m). Waist circumference, body mass index and diabetes mellitus were significant predictors of steatosis. Out of 97 patients, 19 were positive for AMA, 4 for anti-Sp100, 1 for anti-Gp210 and 7 were diagnosed with primary biliary cholangitis. Among SSc patients, hepatic fibrosis biomarkers and AMA prevalence are relatively high, suggesting the opportunity of performing a transient elastography and a screening for hepatic autoimmunity at diagnosis and/or during disease progression.

Targeting Systemic Sclerosis from Pathogenic Mechanisms to Clinical Manifestations: Why IL-6?

Systemic sclerosis (SS) is a chronic autoimmune disorder, which has both cutaneous and systemic clinical manifestations. The disease pathogenesis includes a triad of manifestations, such as vasculopathy, autoimmunity, and fibrosis. Interleukin-6 (IL-6) has a special role in SS development, both in vascular damage and in the development of fibrosis. In the early stages, IL-6 participates in vascular endothelial activation and apoptosis, leading to the release of damage-associated molecular patterns (DAMPs), which maintain inflammation and autoimmunity. Moreover, IL-6 plays an important role in the development of fibrotic changes by mediating the transformation of fibroblasts into myofibroblasts. All of these are associated with disabling clinical manifestations, such as skin thickening, pulmonary fibrosis, pulmonary arterial hypertension (PAH), heart failure, and dysphagia. Tocilizumab is a humanized monoclonal antibody that inhibits IL-6 by binding to the specific receptor, thus preventing its proinflammatory and fibrotic actions. Anti-IL-6 therapy with Tocilizumab is a new hope for SS patients, with data from clinical trials supporting the favorable effect, especially on skin and lung damage.

Management of Endothelial Dysfunction in Systemic Sclerosis: Current and Developing Strategies

Systemic Sclerosis (SSc) is an autoimmune disease marked by dysregulation of the immune system, tissue fibrosis and dysfunction of the vasculature. Vascular damage, remodeling and inadequate endothelial repair are hallmarks of the disease. Since early stages of SSc, damage and apoptosis of endothelial cells (ECs) can lead to perivascular inflammation, oxidative stress and tissue hypoxia, resulting in multiple clinical manifestations. Raynaud's phenomenon, edematous puffy hands, digital ulcers, pulmonary artery hypertension, erectile dysfunction, scleroderma renal crisis and heart involvement severely affect quality of life and survival. Understanding pathogenic aspects and biomarkers that reflect endothelial damage in SSc is essential to guide therapeutic interventions. Treatment approaches described for SSc-associated vasculopathy include pharmacological options to improve blood flow and tissue perfusion and, more recently, cellular therapy to enhance endothelial repair, promote angiogenesis and heal injuries. This mini-review examines the current knowledge on cellular and molecular aspects of SSc vasculopathy, as well as established and developing therapeutic approaches for improving the vascular compartment.

Functions and Inhibition of Galectin-7, an Emerging Target in Cellular Pathophysiology

Galectin-7 is a soluble unglycosylated lectin that is able to bind specifically to β-galactosides. It has been described to be involved in apoptosis, proliferation and differentiation, but also in cell adhesion and migration. Several disorders and diseases are discussed by covering the aforementioned biological processes. Structural features of galectin-7 are discussed as well as targeting the protein intracellularly or extracellularly. The exact molecular mechanisms that lie behind many biological processes involving galectin-7 are not known. It is therefore useful to come up with chemical probes or tools in order to obtain knowledge of the physiological processes. The objective of this review is to summarize the roles and functions of galectin-7 in the human body, providing reasons why it is necessary to design inhibitors for galectin-7, to give the reader structural insights and describe its current inhibitors.

Endothelial CCR6 expression due to FLI1 deficiency contributes to vasculopathy associated with systemic sclerosis

Background

We have recently demonstrated that serum CCL20 levels positively correlate with mean pulmonary arterial pressure in patients with systemic sclerosis (SSc). Considering a proangiogenic effect of CCL20 on endothelial cells via CCR6, the CCL20/CCR6 axis may contribute to the development of SSc vasculopathy. Therefore, we explored this hypothesis using clinical samples, cultured cells, and murine SSc models.

Methods

The expression levels of CCL20 and CCR6 in the skin, mRNA levels of target genes, and the binding of transcription factor FLI1 to the target gene promoter were evaluated by immunostaining, quantitative reverse transcription PCR, and chromatin immunoprecipitation, respectively. Vascular permeability was evaluated by Evans blue dye injection in bleomycin-treated mice. Angiogenic activity of endothelial cells was assessed by in vitro angiogenesis assay.

Results

CCL20 expression was significantly elevated in dermal fibroblasts of patients with early diffuse cutaneous SSc, while CCR6 was significantly up-regulated in dermal small vessels of SSc patients irrespective of disease subtypes and disease duration. In human dermal microvascular endothelial cells, FLI1 siRNA induced the expression of CCR6, but not CCL20, and FLI1 bound to the CCR6 promoter. Importantly, vascular permeability, a representative SSc-like vascular feature of bleomycin-treated mice, was attenuated by Ccr6 siRNA treatment, and CCR6 siRNA suppressed the angiogenic activity of human dermal microvascular endothelial cells assayed by in vitro tube formation.

Conclusions

The increased expression of endothelial CCR6 due to FLI1 deficiency may contribute to the development of SSc vasculopathy.

The role of the Notch pathway in the pathogenesis of systemic sclerosis: clinical implications

INTRODUCTION

Systemic sclerosis (SSc) is a chronic debilitating disease characterized by vascular insufficiency, widespread fibrosis and immune activation. Current understanding of its pathophysiology remains incomplete, which translates into inefficient therapies. Notch signaling is a central player in the development of physiological and pathological fibrosis not only in general but also in the context of SSc and is most likely involved in the vascular dysfunction that characterizes the disease.

AREAS COVERED

This review explores the role of the Notch pathway in the pathophysiology of SSc and the potential implications for the diagnosis, evaluation, and management of this yet incurable disease.

EXPERT OPINION

Although major issues still exist about the comprehension of SSc and the design of effective treatments, the knowledge of the role of the Notch pathway in fibrogenesis and vascular biology has shed light and enthusiasm over the field. Drugs that target components of Notch signaling are currently in development including already some in clinical trials. As such, Notch may become a very important topic in the near future (considering both the pathophysiology and treatment perspectives), not only in the context of SSc but also in the vascular-dependent fibrotic processes present in a multitude of diseases.

Systemic sclerosis sine scleroderma in children

Objective

Juvenile systemic sclerosis (JSSc) is a rare condition in childhood and its variety with no skin involvement, sine scleroderma (ssJSSc), is anecdotal. We report the first case series of patients with ssJSSc.

Methods

Demographic, clinical and laboratory data of patients with JSSc followed at our centre were retrospectively collected. Patients with no skin involvement but with all of the features RP, positive ANA, intestinal dysmotility and/or interstitial lung disease (ILD) or pulmonary arterial hypertension (PAH) and/or cardiac or renal involvement typical of scleroderma were defined as having ssJSSc and compared with those with classic JSSc (cJSSc).

Results

Among 52 JSSc patients seen in 20 years, five (9.6%) presented with ssJSSc. Their clinical features and those of the only two patients reported in the literature so far were compared with classic JSSc with available complete data. Six patients had cardiac involvement as presenting feature, three primary cardiomyopathy, three secondary to PAH. Two patients died after a brief disease course and one rapidly underwent heart transplantation. In comparison with cJSSc, ssJSSc showed a significantly longer diagnostic delay (20.1 vs 8.3 months, P = 0.017), higher frequency of cardiac involvement (85.7 vs 15.6%, P = 0.001) and worse outcome, intended as mortality or end-stage organ failure rates (42.9% vs 6.2%, P < 0.001).

Conclusion

Cardiac involvement represents the most important characteristic of ssJSSc and carries a high morbidity and mortality rate. The longer delay in diagnosis underlines the need for a comprehensive rheumatological work-up in patients with isolated cardiomyopathy or PAH/ILD.

Similarities between COVID-19 and systemic sclerosis early vasculopathy: A "viral" challenge for future research in scleroderma

OBJECTIVE

To review similarities between COVID-19 and systemic sclerosis (SSc) early vasculopathy to provide novel insights into both diseases.

METHODS

A narrative review of the literature supplemented with expert opinion.

RESULTS

There is clear evidence that the endothelium is at the centre stage in SSc and COVID-19, with endothelial cell activation/injury and dysfunction creating the crucial evolving step in the pathogenesis of both diseases. The angiotensin system has also been implicated in the early stages of both COVID-19 and SSc. Autoptic studies provide novel insights into the effects of SARS-CoV-2 on the endothelium. Normal endothelium and endothelial dysfunction in COVID-19 and SSc are discussed. It is debated whether SARS-CoV-2 infection triggers autoimmunity with production of autoantibodies which is of mechanistic interest because other viral illnesses are potentially involved in endothelial dysfunction and in SSc pathogenesis.

CONCLUSION

COVID-19 is due to a direct assault of SARS-CoV-2 on the vascular system as an acute infection, whereas SSc remains a chronic/sub-acute autoimmune disease of largely unknown etiology Further study and exploration of the SARS-CoV-2 pathogenic mechanisms might provide further useful milestones in the understanding of the early SSc pathogenesis.

Arterial evaluation of systemic sclerosis patients with Doppler ultrasound: What did we find?

AIM

The aim of this study was to detect macrovascular findings in systemic sclerosis (SSc) by means of color Doppler ultrasonography (CDUS) and to evaluate the relationship between the laboratory and clinical findings in the setting of the disease.

METHODS

This was a cross-sectional study. Eighty-eight patients were included in the study. CDUS examinations of the bilateral carotid, vertebral, and peripheral arteries were performed. The presence of macrovascular involvement was investigated and recorded, and its relationships with the clinical, laboratory, and cardiovascular risk factors were evaluated.

RESULTS

An atheromatous plaque was found in 67.7% of the 1936 arteries examined by CDUS. Of these 1936 arteries, 37.4% demonstrated a narrowing of the intraluminal diameter. On the other hand, the carotid intima-media thickness (CIMT) was found to have increased in 55.7% of the patients. This increase was found to be statistically correlated with disease duration, the modified Rodnan Skin Thickness Score, and the Medsger Disease Activity Score. But no relation existed with the disease subtype, age, or cardiovascular risk factors. Arterial occlusion was detected in 10 patients. An association was found between the CIMT values and arterial occlusion.

CONCLUSIONS

In this study, we examined the arteries by means of CDUS, and we detected structural alterations in the peripheral and carotid arteries. We witnessed that these macrovascular changes had a close association with certain features of SSc. We think there is a need for broader prospective studies in order to evaluate the contribution of these factors to the macrovascular changes stated in the article.

Peripheral Vascular Abnormalities in Anorexia Nervosa: A Psycho-Neuro-Immune-Metabolic Connection

Immune, neuroendocrine, and autonomic nervous system dysregulation in anorexia nervosa lead to cardiovascular complications that can potentially result in increased morbidity and mortality. It is suggested that a complex non-invasive assessment of cardiovascular autonomic regulation-cardiac vagal control, sympathetic vascular activity, and cardiovascular reflex control-could represent a promising tool for early diagnosis, personalized therapy, and monitoring of therapeutic interventions in anorexia nervosa particularly at a vulnerable adolescent age. In this view, we recommend to consider in the diagnostic route, at least in the subset of patients with peripheral microvascular symptoms, a nailfold video-capillaroscopy as an easy not invasive tool for the early assessing of possible cardiovascular involvement.

Fli1 deficiency suppresses RALDH1 activity of dermal dendritic cells and related induction of regulatory T cells: a possible role in scleroderma

BACKGROUND

Aldehyde dehydrogenase 1 family member A1 (RALDH1)-producing dermal dendritic cells (DCs), a conventional DC subset regulating skin fibrosis, are decreased in the involved skin of patients with systemic sclerosis (SSc). In this study, we investigated the contribution of Fli1 deficiency, a potential predisposing factor of SSc, to the phenotypical alteration of RALDH1-producing dermal DCs by using SSc model mice and SSc skin samples.

METHODS

Bleomycin (BLM)-induced skin fibrosis was generated with Fli1^+/- and wild-type mice. The proportions of DC and CD4⁺ T cell subsets were determined by flow cytometry in the dermis of BLM-treated mice. Fli1 expression in dermal DCs was evaluated by immunofluorescence with skin samples of SSc and healthy control subjects.

RESULTS

RALDH activity of dermal DCs was significantly decreased in BLM-treated Fli1^+/- mice compared with BLM-treated wild-type mice, whereas the proportion of CD103^-CD11b^- dermal DCs, a major DC subset producing RALDH1 in response to BLM injection, was comparable between groups. Relevant to this finding, the proportion of regulatory T cells (Tregs) in the dermis was decreased in BLM-treated Fli1^+/- mice relative to BLM-treated wild-type mice, while the proportions of Th1, Th2 and Th17 cells were unaltered. In the involved skin of SSc patients, Fli1 was downregulated in CD11c⁺ cells, including dermal DCs.

CONCLUSIONS

Fli1 deficiency inhibits RALDH1 activity of CD103^-CD11b^- dermal DCs and related induction of Tregs in BLM-treated mice. Considering Fli1 reduction in SSc dermal DCs, Fli1deficiency may impair the dermal DC-Treg system, contributing to the development of skin fibrosis in SSc.

Endothelial-to-mesenchymal transition in systemic sclerosis

Systemic sclerosis (SSc) is an autoimmune disease characterized by significant vascular alterations and multi-organ fibrosis. Microvascular alterations are the first event of SSc and injured endothelial cells (ECs) may transdifferentiate towards myofibroblasts, the cells responsible for fibrosis and collagen deposition. This process is identified as endothelial-to-mesenchymal transition (EndMT), and understanding of its development is pivotal to identify early pathogenetic events and new therapeutic targets for SSc. In this review, we have highlighted the molecular mechanisms of EndMT and summarize the evidence of the role played by EndMT during the development of progressive fibrosis in SSc, also exploring the possible therapeutic role of its inhibition.

Regulation of Monocyte Adhesion and Type I Interferon Signaling by CD52 in Patients With Systemic Sclerosis

OBJECTIVE

Systemic sclerosis (SSc) is characterized by dysregulation of type I interferon (IFN) signaling. CD52 is known for its immunosuppressive functions in T cells. This study was undertaken to investigate the role of CD52 in monocyte adhesion and type I IFN signaling in patients with SSc.

METHODS

Transcriptome profiles of circulating CD14+ monocytes from patients with limited cutaneous SSc (lcSSc), patients with diffuse cutaneous SSc (dcSSs), and healthy controls were analyzed by RNA sequencing. Levels of CD52, CD11b/integrin αΜ, and CD18/integrin β2 in whole blood were assessed by flow cytometry. CD52 expression was analyzed in relation to disease phenotype (early, lcSSc, dcSSc) and autoantibody profiles. The impact of overexpression, knockdown, and antibody blocking of CD52 was analyzed by gene and protein expression assays and functional assays.

RESULTS

Pathway enrichment analysis indicated an increase in adhesion- and type I IFN-related genes in monocytes from SSc patients. These cells displayed up-regulated expression of CD11b/CD18, reduced expression of CD52, and enhanced adhesion to intercellular adhesion molecule 1 and endothelial cells. Changes in CD52 expression were consistent with the SSc subtypes, as well as with immunosuppressive treatments, autoantibody profiles, and monocyte adhesion properties in patients with SSc. Overexpression of CD52 led to decreased levels of CD18 and monocyte adhesion, while knockdown of CD52 increased monocyte adhesion. Experiments with the humanized anti-CD52 monoclonal antibody alemtuzumab in blood samples from healthy controls increased monocyte adhesion and CD11b/CD18 expression, and enhanced type I IFN responses. Monocytic CD52 expression was up-regulated by interleukin-4 (IL-4)/IL-13 via the STAT6 pathway, and was down-regulated by lipopolysaccharide and IFNs α, β, and γ in a JAK1 and histone deacetylase IIa (HDAC IIa)-dependent manner.

CONCLUSION

Down-regulation of the antiadhesion CD52 antigen in CD14+ monocytes represents a novel mechanism in the pathogenesis of SSc. Targeting of the IFN-HDAC-CD52 axis in monocytes might represent a new therapeutic option for patients with early SSc.

Association of serum CCL20 levels with pulmonary vascular involvement and primary biliary cholangitis in patients with systemic sclerosis

AIM

Systemic sclerosis (SSc) is a chronic autoimmune disease resulting in vasculopathy and fibrosis of the skin and major internal organs. Especially, interstitial lung disease and pulmonary arterial hypertension are the leading causes of mortality. C-C motif ligand 20 (CCL20) is known as a homeostatic and inflammatory chemokine, which is associated with fibrosis and angiogenesis and constantly expressed in organs involved in SSc. Therefore, we investigated the potential contribution of CCL20 to the development of SSc.

METHOD

We conducted cross-sectional analyses of 67 SSc patients and 20 healthy controls recruited in a single center for 9 years. Serum CCL20 levels were measured by enzyme-linked immunosorbent assay. Statistical analyses were performed with the Mann-Whitney U test, the Kruskal-Wallis test followed by Dunn's multiple comparison test, Fisher's exact probability test and the Spearman's rank correlation coefficient.

RESULTS

SSc patients had significantly higher serum CCL20 levels than healthy controls. In SSc patients, serum CCL20 levels correlated inversely with the percentage of predicated diffusion lung capacity for carbon monoxide and positively with mean pulmonary artery pressure (mPAP). In addition, SSc patients with increased serum CCL20 levels had anti-mitochondrial antibody M2 titer significantly elevated relative to those with normal levels, and SSc patients with asymptomatic primary biliary cholangitis (PBC) possessed higher serum CCL20 levels than those without. Importantly, serum CCL20 levels were associated positively with mPAP values and PBC presence by multivariate regression analysis.

CONCLUSION

Serum CCL20 levels may be involved in the development of pulmonary vascular involvement leading to pulmonary arterial hypertension and asymptomatic PBC in SSc patients.