Assessment of disease outcome measures in systemic sclerosis

Exploring the mechanism of luteolin improving immune and inflammatory responses in systemic sclerosis based on systems biology and cell experiments

There is a growing trend of applying traditional Chinese medicine (TCM) to treat immune diseases. This study reveals the possible mechanism of luteolin, an active ingredient in the core prescription of TCM, in alleviating systemic sclerosis (SSc) inflammation. Bibliometrics was performed to retrieve the core keywords of SSc inflammation. The key inflammatory indicators in the serum samples of 50 SSc patients were detected by ELISA. Data mining was applied for correlation analysis, association rule analysis, and binary logistic regression analysis on the clinical indicators and medication of 50 SSc patients before and after treatment to determine the core prescription. Network pharmacology was used for identifying candidate genes and pathways; molecular docking was conducted to determine the core monomer components of the prescription, providing a basis for subsequent in vitro molecular mechanism research. The effect of luteolin on SSc-human dermal fibroblasts (HDF) viability and inflammatory factors was evaluated by means of ELISA, RT-PCR, and Western blot. The role of TNF in inflammation was explored by using a TNF overexpression vector, NF-κB inhibitor (PKM2), and SSc-HDF. The involvement of TNF/NF-κB pathway was validated by RT-PCR, Western blot, and immunofluorescence. TCM treatment partially corrected the inflammatory changes in SSc patients, indicating its anti-inflammatory effects in the body. Atractylodes, Yam, Astragalus root, Poria cocos, Pinellia ternata, Salvia miltiorrhiza, Safflower, Cassia twig, and Angelica were identified as the core prescriptions for improving inflammatory indicators. Luteolin was the main active ingredient in the prescription and showed a strong binding energy with TNF and NF-κB. Luteolin exerted anti-inflammatory effects in vitro by reducing inflammatory cytokines in SSc-HDF and inhibiting the activation of TNF/NF-κB. Mechanistically, luteolin inhibited the activation of the TNF/NF-κB pathway in SSc-HDF, as manifested by an increase in extranuclear p-P65 and TNF but a decrease in intranuclear p-P65. Interestingly, the addition of PKM2 augmented the therapeutic function of luteolin against inflammation in SSc-HDF. Our study showed the TCM alleviates the inflammatory response of SSc by inhibiting the activation of the TNF/NF-κB pathway and is an effective therapeutic agent for the treatment of SSc.

High-resolution peripheral quantitative computed tomography for the assessment of acro-osteolysis and calcinosis in patients with systemic sclerosis

OBJECTIVE

To assist the development of future treatments in systemic sclerosis (SSc), the development of reliable outcome measures is pivotal. We aimed to evaluate the use of high-resolution peripheral quantitative CT (HR-pQCT) for visualization and gradation of acro-osteolysis (AO) and calcinosis compared to conventional hand radiographs (CR) in patients with SSc.

METHODS

HR-pQCT scans of the 2nd to 4th fingers, CR, nail fold capillaroscopy, and a clinical examination were conducted. Images were reviewed for the presence and degree of AO and calcinosis according to semiquantitative grading scales.

RESULTS

Forty patients were included. Fourteen had AO according to CR, whereas HR-pQCT revealed AO in 18 patients. The sensitivity and specificity of classifying patients as having AO by HR-pQCT when CR was used as reference were 93% (95% CI: 66-99%) and 80% (95% CI: 59-93%), respectively. By CR and with HR-pQCT as reference, the sensitivity and specificity were 72% (95% CI: 47-90%) and 95% (95% CI: 76-99%). Patients with AO had more or larger calcifications than patients without AO according to the proposed HR-pQCT grading system, with a median grade of 2 (IQR: 1-3) versus 0 (IQR: 0-1) (P<0.01). Grade 3 changes were observed exclusively in patients with AO (n=6/14, 42.9%). Assessment of AO and calcinosis by HR-pQCT demonstrated moderate to excellent test-retest reliability.

CONCLUSION

HR-pQCT allowed precise and reliable classification and grading of acro-osteolysis and acral calcinosis. The modality could prove helpful for detecting and monitoring these lesions as well as facilitating early diagnosis and guide treatment of these patients.

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

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Development and validation of a new diagnostic prediction model of ENHO and NOX4 for early diagnosis of systemic sclerosis

Objective

Systemic sclerosis (SSc) is a chronic autoimmune disease characterized by fibrosis. The challenge of early diagnosis, along with the lack of effective treatments for fibrosis, contribute to poor therapeutic outcomes and high mortality of SSc. Therefore, there is an urgent need to identify suitable biomarkers for early diagnosis of SSc.

Methods

Three skin gene expression datasets of SSc patients and healthy controls were downloaded from Gene Expression Omnibus (GEO) database (GSE130955, GSE58095, and GSE181549). GSE130955 (48 early diffuse cutaneous SSc and 33 controls) were utilized to screen differentially expressed genes (DEGs) between SSc and normal skin samples. Least absolute shrinkage and selection operator (LASSO) regression and support vector machine recursive feature elimination (SVM-RFE) were performed to identify diagnostic genes and construct a diagnostic prediction model. The results were further validated in GSE58095 (61 SSc and 36 controls) and GSE181549 (113 SSc and 44 controls) datasets. Receiver operating characteristic (ROC) curves were applied for assessing the level of diagnostic ability. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to verify the diagnostic genes in skin tissues of out cohort (10 SSc and 5 controls). Immune infiltration analysis were performed using CIBERSORT algorithm.

Results

A total of 200 DEGs were identified between SSc and normal skin samples. Functional enrichment analysis revealed that these DEGs may be involved in the pathogenesis of SSc, such as extracellular matrix remodeling, cell-cell interactions, and metabolism. Subsequently, two critical genes (ENHO and NOX4) were identified by LASSO and SVM-RFE. ENHO was found down-regulated while NOX4 was up-regulated in skin of SSc patients and their expression levels were validated by above three datasets and our cohort. Notably, these differential expressions were more pronounced in patients with diffuse cutaneous SSc than in those with limited cutaneous SSc. Next, we developed a novel diagnostic model for SSc using ENHO and NOX4, which demonstrated strong predictive power in above three cohorts and in our own cohort. Furthermore, immune infiltration analysis revealed dysregulated levels of various immune cell subtypes within early SSc skin specimens, and a negative correlation was observed between the levels of ENHO and Macrophages M1 and M2, while a positive correlation was observed between the levels of NOX4 and Macrophages M1 and M2.

Conclusion

This study identified ENHO and NOX4 as novel biomarkers that can be serve as a diagnostic prediction model for early detection of SSc and play a potential role in the pathogenesis of the disease.

Biomarkers in the Pathogenesis, Diagnosis, and Treatment of Systemic Sclerosis

Systemic sclerosis (SSc) is a complex autoimmune disease characterized by vascular damage, vasoinstability, and decreased perfusion with ischemia, inflammation, and exuberant fibrosis of the skin and internal organs. Biomarkers are analytic indicators of the biological and disease processes within an individual that can be accurately and reproducibly measured. The field of biomarkers in SSc is complex as recent studies have implicated at least 240 pathways and dysregulated proteins in SSc pathogenesis. Anti-nuclear antibodies (ANA) are classical biomarkers with well-described clinical classifications and are present in more than 90% of SSc patients and include anti-centromere, anti-Th/To, anti-RNA polymerase III, and anti-topoisomerase I antibodies. Transforming growth factor-β (TGF-β) is central to the fibrotic process of SSc and is intimately intertwined with other biomarkers. Tyrosine kinases, interferon-1 signaling, IL-6 signaling, endogenous thrombin, peroxisome proliferator-activated receptors (PPARs), lysophosphatidic acid receptors, and amino acid metabolites are new biomarkers with the potential for developing new therapeutic agents. Other biomarkers implicated in SSc-ILD include signal transducer and activator of transcription 4 (STAT4), CD226 (DNAX accessory molecule 1), interferon regulatory factor 5 (IRF5), interleukin-1 receptor-associated kinase-1 (IRAK1), connective tissue growth factor (CTGF), pyrin domain containing 1 (NLRP1), T-cell surface glycoprotein zeta chain (CD3ζ) or CD247, the NLR family, SP-D (surfactant protein), KL-6, leucine-rich α2-glycoprotein-1 (LRG1), CCL19, genetic factors including DRB1 alleles, the interleukins (IL-1, IL-4, IL-6, IL-8, IL-10 IL-13, IL-16, IL-17, IL-18, IL-22, IL-32, and IL-35), the chemokines CCL (2,3,5,13,20,21,23), CXC (8,9,10,11,16), CX3CL1 (fractalkine), and GDF15. Adiponectin (an indicator of PPAR activation) and maresin 1 are reduced in SSc patients. A new trend has been the use of biomarker panels with combined complex multifactor analysis, machine learning, and artificial intelligence to determine disease activity and response to therapy. The present review is an update of the various biomarker molecules, pathways, and receptors involved in the pathology of SSc.

The role of immunosuppressive myofibroblasts in the aging process and age-related diseases

Tissue-resident fibroblasts are mesenchymal cells which control the structural integrity of the extracellular matrix (ECM). Fibroblasts possess a remarkable plasticity to allow them to adapt to the changes in the microenvironment and thus maintain tissue homeostasis. Several stresses, also those associated with the aging process, convert quiescent fibroblasts into myofibroblasts which not only display fibrogenic properties but also act as immune regulators cooperating both with tissue-resident immune cells and those immune cells recruited into affected tissues. TGF-β cytokine and reactive oxygen species (ROS) are major inducers of myofibroblast differentiation in pathological conditions either from quiescent fibroblasts or via transdifferentiation from certain other cell types, e.g., macrophages, adipocytes, pericytes, and endothelial cells. Intriguingly, TGF-β and ROS are also important signaling mediators between immunosuppressive cells, such as MDSCs, Tregs, and M2 macrophages. It seems that in pathological states, myofibroblasts are able to interact with the immunosuppressive network. There is clear evidence that a low-grade chronic inflammatory state in aging tissues is counteracted by activation of compensatory immunosuppression. Interestingly, common enhancers of the aging process, such as oxidative stress, loss of DNA integrity, and inflammatory insults, are inducers of myofibroblasts, whereas anti-aging treatments with metformin and rapamycin suppress the differentiation of myofibroblasts and thus prevent age-related tissue fibrosis. I will examine the reciprocal interactions between myofibroblasts and immunosuppressive cells within aging tissues. It seems that the differentiation of myofibroblasts with age-related harmful stresses enhances the activity of the immunosuppressive network which promotes tissue fibrosis and degeneration in elderly individuals.

Biomarkers in Systemic Sclerosis: An Overview

Systemic sclerosis (SSc) is a complex autoimmune disease characterized by significant fibrosis of the skin and internal organs, with the main involvement of the lungs, kidneys, heart, esophagus, and intestines. SSc is also characterized by macro- and microvascular damage with reduced peripheral blood perfusion. Several studies have reported more than 240 pathways and numerous dysregulation proteins, giving insight into how the field of biomarkers in SSc is still extremely complex and evolving. Antinuclear antibodies (ANA) are present in more than 90% of SSc patients, and anti-centromere and anti-topoisomerase I antibodies are considered classic biomarkers with precise clinical features. Recent studies have reported that trans-forming growth factor β (TGF-β) plays a central role in the fibrotic process. In addition, interferon regulatory factor 5 (IRF5), interleukin receptor-associated kinase-1 (IRAK-1), connective tissue growth factor (CTGF), transducer and activator of transcription signal 4 (STAT4), pyrin-containing domain 1 (NLRP1), as well as genetic factors, including DRB1 alleles, are implicated in SSc damage. Several interleukins (e.g., IL-1, IL-6, IL-10, IL-17, IL-22, and IL-35) and chemokines (e.g., CCL 2, 5, 23, and CXC 9, 10, 16) are elevated in SSc. While adiponectin and maresin 1 are reduced in patients with SSc, biomarkers are important in research but will be increasingly so in the diagnosis and therapeutic approach to SSc. This review aims to present and highlight the various biomarker molecules, pathways, and receptors involved in the pathology of SSc.

Antibody-mediated neutralization of galectin-3 as a strategy for the treatment of systemic sclerosis

Systemic sclerosis (SSc) is an autoimmune, inflammatory and fibrotic disease with limited treatment options. Developing new therapies is therefore crucial to address patient needs. To this end, we focused on galectin-3 (Gal-3), a lectin known to be associated with several pathological processes seen in SSc. Using RNA sequencing of whole-blood samples in a cross-sectional cohort of 249 patients with SSc, Gal-3 and its interactants defined a strong transcriptomic fingerprint associated with disease severity, pulmonary and cardiac malfunctions, neutrophilia and lymphopenia. We developed new Gal-3 neutralizing monoclonal antibodies (mAb), which were then evaluated in a mouse model of hypochlorous acid (HOCl)-induced SSc. We show that two of these antibodies, D11 and E07, reduced pathological skin thickening, lung and skin collagen deposition, pulmonary macrophage content, and plasma interleukin-5 and -6 levels. Moreover, E07 changed the transcriptional profiles of HOCl-treated mice, resulting in a gene expression pattern that resembled that of control mice. Similarly, pathological pathways engaged in patients with SSc were counteracted by E07 in mice. Collectively, these findings demonstrate the translational potential of Gal-3 blockade as a therapeutic option for SSc.

Low cognitive functioning and depressive symptoms in patients with rheumatoid arthritis and systemic sclerosis: a clinical study

BACKGROUND

Recently, cognitive deficits occurring in rheumatic diseases have attracted scientific attention. Cognitive symptoms in patients with Rheumatoid Arthritis (RA) and Systemic Sclerosis (SSc) have not been thoroughly studied. This study aimed to assess cognitive function and its relationship with depressive symptoms in RA and SSc and compare it to mild neurocognitive disorder due to Alzheimer's disease (MiND) and to individuals without cognitive impairment.

METHODS

Cognitive function and depressive symptoms were tapped with the Cognitive Telephone Screening Instrument plus (COGTEL+), the Serial Seven Test (SST), the Mini-Mental State Examination (MMSE) and the Geriatric Depression scale-15 (GDS), respectively. Statistical analyses included between groups-, correlation- and regression analyses. Demographic characteristics were considered in the regression models.

RESULTS

The study included 30 individuals with RA, 24 with SSc, 26 adults without cognitive impairment and 33 individuals with MiND. Lower performance in verbal short-term memory, concentration/attention, verbal fluency and MMSE in patients with RA compared to individuals without cognitive impairment was detected. Of note, performance on verbal fluency, concentration/attention, inductive reasoning and MMSE was lower in RA compared to MiND. Individuals with SSc performed worse in verbal fluency and in MMSE in comparison to adults without cognitive deficits. Verbal fluency deficits in SSc exceeded that in MiND. Performance on MMSE, COGTEL+, prospective memory, working memory, verbal fluency and concentration/attention was related to GDS scores, which did not vary across the groups.

CONCLUSIONS

Patients with RA and SSc encountered cognitive dysfunction, which partially pertains to depressive symptoms. Of note, the severity of cognitive dysfunction in many cases exceeded that of MiND.

Malignancies in systemic rheumatic diseases: A mini review

There is an increased risk of malignancies in patients with many systemic rheumatic diseases, which negatively impact on their quality of life. The risk and types of malignancies can differ by the type of rheumatic diseases. Possible mechanisms linking them are dynamic and complicated, including chronic inflammation and damage in rheumatic disease, inability to clear oncogenic infections, shared etiology and some anti-rheumatic therapies. Although certain disease-modifying anti-rheumatic drugs (DMARDs) have been proved to be potentially carcinogenic, the majority of them were not associated with increased risk of most malignancies in patients with systemic rheumatic diseases.