The multifaceted problem of pulmonary arterial hypertension in systemic sclerosis

Exploring the Genetic Association Between Connective Tissue Diseases and the Risk of Pulmonary Arterial Hypertension: A Mendelian Randomization Analysis

This study aimed to explore the potential causal link between genetic predisposition to various connective tissue diseases (CTDs), namely systemic lupus erythematosus (SLE), Sjögren's syndrome (SS), polymyositis (PM), dermatomyositis (DM), systemic sclerosis (SSc), mixed connective tissue disease (MCTD), and rheumatoid arthritis (RA), and the incidence of pulmonary arterial hypertension (PAH) utilizing Mendelian randomization (MR). Employing a two-sample MR approach, genetic variants associated with CTDs served as instrumental variables to investigate the exposure-outcome relationship, with GWAS data sourced from the FinnGen Biobank. Comprehensive statistical analyses, including the inverse variance weighted (IVW) method, were conducted, alongside heterogeneity, pleiotropy, and sensitivity tests to ensure the robustness and validity of findings. The results revealed that in the Finnish population, no significant causal associations were identified between PAH and SLE, SS, PM, DM, MCTD, or RA. Notably, a significant association was observed between SSc and an increased risk of PAH (IVW: OR = 1.278, 95% CI = 1.061-1.540, p = 0.010). However, this finding was not replicated in other European populations. These results indicate the unique genetic and pathological pathways underlying SSc-associated PAH, emphasizing the need for tailored screening and management protocols in this patient group.

High resolution computed tomography in systemic sclerosis: From diagnosis to follow-up

Early diagnosis of interstitial lung disease (ILD) and pulmonary hypertension (PH) is crucial in systemic sclerosis (SSc) for both management and treatment. However, diagnosing SSc-ILD can be challenging because symptoms of lung involvement are often non-specific at the early stages of disease. High-resolution computed tomography (HRCT) of the chest is recognized as the most accurate imaging modality for baseline and follow-up evaluation of SSc-ILD. Key features of SSc-ILD on HRCT include a non-specific interstitial pneumonia (NSIP) pattern, with peripheral ground-glass opacities and extensive traction bronchiectasis. Less common HRCT manifestations include usual interstitial pneumonia (UIP) pattern, followed by diffuse alveolar damage (DAD), diffuse alveolar hemorrhage (DAH) and organizing pneumonia (OP). The extent of disease on HRCT is known to relate with prognosis and serial assessments can be helpful in monitoring disease progression or treatment response. We discuss the main chest computed tomography (CT) manifestations of SSc, highlighting the role of imaging at both baseline and follow-up evaluations.

Emergencies in inflammatory rheumatic diseases

Inflammatory rheumatic diseases (IRDs), encompassing a broad spectrum of chronic disorders, typically necessitate prolonged therapeutic intervention. Nevertheless, these diseases can sometimes manifest as severe emergencies requiring prompt and extensive medical intervention. Urgent intervention is essential for effectively recognizing and managing these situations, as they have the potential to be life-threatening and can result in severe morbidity and mortality. Emergencies in IRDs can occur with different frequencies and manifestations, including nervous system issues, severe infections, thrombosis-emboli, renal crises, gastrointestinal issues, and cardiovascular events. The fact that these events can occur across different IRDs underscores the necessity for heightened awareness and readiness among healthcare professionals. The pathophysiologic mechanisms that cause rheumatic emergencies are complex and involve multiple factors. These emergencies frequently arise due to the interplay between the inflammatory characteristics of rheumatic diseases and different systemic triggers. Early detection and treatment can have a substantial impact on an individual's prognosis in cases of severe and life-threatening disorders that require prompt recognition. Rapid decision-making and urgent care are required to effectively address rheumatic emergencies, as well as the implementation of a diagnostic flowchart. This article provides an overview of the emergencies linked to IRDs, classifying and assessing them individually. This article aims to enhance healthcare professionals' knowledge and awareness of critical situations by examining current recommendations and pathophysiological information. Implementing standardized diagnostic and treatment methods, providing patient education, and conducting continuing research into the underlying mechanisms are essential for enhancing the management of these critical situations and improving patient outcomes.

Metabolic fingerprinting of systemic sclerosis: a systematic review

Introduction: Systemic sclerosis (SSc) is a chronic autoimmune disease, marked by an unpredictable course, high morbidity, and increased mortality risk that occurs especially in the diffuse and rapidly progressive forms of the disease, characterized by fibrosis of the skin and internal organs and endothelial dysfunction. Recent studies suggest that the identification of altered metabolic pathways may play a key role in understanding the pathophysiology of the disease. Therefore, metabolomics might be pivotal in a better understanding of these pathogenic mechanisms. Methods: Through a systematic review of the literature following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Guidelines (PRISMA), searches were done in the PubMed, EMBASE, Web of Science, and Scopus databases from 2000 to September 2022. Three researchers independently reviewed the literature and extracted the data based on predefined inclusion and exclusion criteria. Results: Of the screened studies, 26 fulfilled the inclusion criteria. A total of 151 metabolites were differentially distributed between SSc patients and healthy controls (HC). The main deregulated metabolites were those derived from amino acids, specifically homocysteine (Hcy), proline, alpha-N-phenylacetyl-L-glutamine, glutamine, asymmetric dimethylarginine (ADMA), citrulline and ornithine, kynurenine (Kyn), and tryptophan (Trp), as well as acylcarnitines associated with long-chain fatty acids and tricarboxylic acids such as citrate and succinate. Additionally, differences in metabolic profiling between SSc subtypes were identified. The diffuse cutaneous systemic sclerosis (dcSSc) subtype showed upregulated amino acid-related pathways involved in fibrosis, endothelial dysfunction, and gut dysbiosis. Lastly, potential biomarkers were evaluated for the diagnosis of SSc, the identification of the dcSSc subtype, pulmonary arterial hypertension, and interstitial lung disease. These potential biomarkers are within amino acids, nucleotides, carboxylic acids, and carbohydrate metabolism. Discussion: The altered metabolite mechanisms identified in this study mostly point to perturbations in amino acid-related pathways, fatty acid beta-oxidation, and in the tricarboxylic acid cycle, possibly associated with inflammation, vascular damage, fibrosis, and gut dysbiosis. Further studies in targeted metabolomics are required to evaluate potential biomarkers for diagnosis, prognosis, and treatment response.

Interstitial Lung Disease: How Should Therapeutics Be Implemented?

Systemic sclerosis-interstitial lung disease (SSc-ILD) is a major complication of SSc resulting in important morbidity and mortality. Next to cyclophosphamide and mycophenolate mofetil, tocilizumab and nintedanib have proven efficacy in the treatment of SSc-ILD. The highly variable course of SSc-ILD, the complexity in determining and predicting the progression of SSc-ILD, and the diversity of treatment options for SSc-ILD, pose many challenges for everyday clinical practice. In this review, currently available evidence for monitoring and treatment of SSc-ILD is summarized and areas where additional evidence is highly desirable are discussed.

Soluble guanylate cyclase stimulation fosters angiogenesis and blunts myofibroblast-like features of systemic sclerosis endothelial cells

OBJECTIVES

In SSc, angiogenesis impairment advances in parallel with the development of fibrosis orchestrated by myofibroblasts originating from different sources, including endothelial-to-mesenchymal transition (EndoMT). Soluble guanylate cyclase (sGC) stimulation has shown antifibrotic effects in SSc skin fibroblasts and mouse models. Here, we investigated the effects of pharmacological sGC stimulation on impaired angiogenesis and myofibroblast-like features of SSc dermal microvascular endothelial cells (SSc-MVECs).

METHODS

To determine whether sGC stimulation affected cell viability/proliferation, SSc-MVECs and healthy dermal MVECs (H-MVECs) were challenged with the sGC stimulator (sGCS) MK-2947 and assayed by annexin V/propidium iodide flow cytometry and the water-soluble tetrazolium salt (WST-1) assay. To study angiogenesis and EndoMT, MK-2947-treated SSc-MVECs were subjected to wound healing and capillary morphogenesis assays and analysed for the expression of endothelial/myofibroblast markers and contractile ability.

RESULTS

MK-2947 treatment did not affect H-MVEC viability/proliferation, while it significantly increased SSc-MVEC proliferation, wound healing capability and angiogenic performance. After MK-2947 treatment, SSc-MVECs exhibited significantly increased proangiogenic MMP9 and decreased antiangiogenic MMP12 and PTX3 gene expression. A significant increase in the expression of CD31 and vascular endothelial cadherin paralleled by a decrease in α-smooth muscle actin, S100A4, type I collagen and Snail1 mesenchymal markers was also found in MK-2947-treated SSc-MVECs. Furthermore, stimulation of sGC with MK-2947 significantly counteracted the intrinsic ability of SSc-MVECs to contract collagen gels and reduced phosphorylated-extracellular signal-regulated kinases 1 and 2 protein levels.

CONCLUSION

These findings demonstrate for the first time that pharmacological sGC stimulation effectively ameliorates the angiogenic performance and blunts the myofibroblast-like profibrotic phenotype of SSc-MVECs, thus providing new evidence for repurposing sGCSs for SSc.

Lung vascular changes as biomarkers of severity in systemic sclerosis-associated interstitial lung disease

OBJECTIVES

It has recently become possible to assess lung vascular and parenchymal changes quantitatively in thoracic CT images using automated software tools. We investigated the vessel parameters of patients with SSc, quantified by CT imaging, and correlated them with interstitial lung disease (ILD) features.

METHODS

SSc patients undergoing standard of care pulmonary function testing and CT evaluation were retrospectively evaluated. CT images were analysed for ILD patterns and total pulmonary vascular volume (PVV) extents with Imbio lung texture analysis. Vascular analysis (volumes, numbers and densities of vessels, separating arteries and veins) was performed with an in-house developed software. A threshold of 5% ILD extent was chosen to define the presence of ILD, and commonly used cut-offs of lung function were adopted.

RESULTS

A total of 79 patients [52 women, 40 ILD, mean age 56.2 (s.d. 14.2) years, total ILD extent 9.5 (10.7)%, PVV/lung volume % 2.8%] were enrolled. Vascular parameters for total and separated PVV significantly correlated with functional parameters and ILD pattern extents. SSc-associated ILD (SSc-ILD) patients presented with an increased number and volume of arterial vessels, in particular those between 2 and 4 mm of diameter, and with a higher density of arteries and veins of <6 mm in diameter. Considering radiological and functional criteria concomitantly, as well as the descriptive trends from the longitudinal evaluations, the normalized PVVs, vessel numbers and densities increased progressively with the increase/worsening of ILD extent and functional impairment.

CONCLUSION

In SSc patients CT vessel parameters increase in parallel with ILD extent and functional impairment, and may represent a biomarker of SSc-ILD severity.

The Use and Utility of Machine Learning in Achieving Precision Medicine in Systemic Sclerosis: A Narrative Review

BACKGROUND

Systemic sclerosis (SSc) is a rare connective tissue disease that can affect different organs and has extremely heterogenous presentations. This complexity makes it difficult to perform an early diagnosis and a subsequent subclassification of the disease. This hinders a personalized approach in clinical practice. In this context, machine learning (ML), a branch of artificial intelligence (AI), is able to recognize relationships in data and predict outcomes.

METHODS

Here, we performed a narrative review concerning the application of ML in SSc to define the state of art and evaluate its role in a precision medicine context.

RESULTS

Currently, ML has been used to stratify SSc patients and identify those at high risk of severe complications. Additionally, ML may be useful in the early detection of organ involvement. Furthermore, ML might have a role in target therapy approach and in predicting drug response.

CONCLUSION

Available evidence about the utility of ML in SSc is sparse but promising. Future improvements in this field could result in a big step toward precision medicine. Further research is needed to define ML application in clinical practice.

Decreased Serum Levels of SIRT1 and SIRT3 Correlate with Severity of Skin and Lung Fibrosis and Peripheral Microvasculopathy in Systemic Sclerosis

Systemic sclerosis (SSc, scleroderma) is a severe autoimmune connective tissue disease characterized by widespread peripheral microvasculopathy, and progressive cutaneous and visceral fibrosis, leading to significant organ dysfunction. Sirtuins (SIRTs) are a family of NAD-dependent protein deacetylases with pleiotropic effects on a variety of biological processes, including metabolism, cell survival, and aging. In the last decades, increasing studies have explored the contribution of SIRTs to the pathogenesis of SSc, highlighting a significant antifibrotic effect of both SIRT1 and SIRT3. On these bases, the aim of this study was to measure circulating SIRT1 and SIRT3 levels by enzyme-linked immune-sorbent assay in a well-characterized cohort of SSc patients (n = 80) and healthy controls (n = 71), focusing on their possible association with disease clinical features, and their potential as biomarkers reflecting SSc activity and severity. Significantly decreased serum levels of both SIRT1 and SIRT3 were found in SSc patients compared to controls. In SSc, the reduction in circulating SIRT1 and SIRT3 associated with a greater extent of cutaneous fibrosis, presence of interstitial lung disease, and worse pulmonary function. Serum SIRT1 and SIRT3 decrease also correlated with the severity of nailfold microvascular damage, with SIRT3 levels being additionally related to the occurrence of digital ulcers. The levels of these two proteins showed a direct correlation with one another in the circulation of SSc patients. Of the two SIRTs, serum SIRT3 was found to better reflect disease activity and severity in a logistic regression analysis model. Our findings suggest that serum SIRT1 and SIRT3 may represent novel potential biomarkers of increased risk for a more severe, life-threatening SSc disease course.

The lncRNAs/miR-30e/CHI3L1 Axis Is Dysregulated in Systemic Sclerosis

Systemic sclerosis (SSc) is an autoimmune disease with completely undefined etiology and treatment difficulties. The expression of both protein coding and non-coding RNAs is dysregulated during disease development. We aimed to examine a possible regulatory axis implemented in the control of chitinase-3 like protein 1 (CHI3L1) or YKL-40, an inflammation-associated glycoprotein, shown to be elevated in SSc. A panel of seven miRNAs and three lncRNAs potentially involved in the control of CHI3L1 were selected on the basis of in silico analysis. TagMan assay was used to evaluate the expression levels of miRNAs and RT-qPCR for lncRNAs in white blood cells (WBCs) and plasma from SSc patients and healthy controls. Among the eight screened miRNAs, miR-30e-5p (p = 0.04) and miR-30a-5p (p = 0.01) were significantly downregulated in WBCs and plasma of SSc patients, respectively. On the contrary, the expression of the metastasis associated lung adenocarcinoma transcript 1 (MALAT1) (p = 0.044) and the Nuclear enriched abundant transcript 1 (NEAT1) (p = 0.008) in WBCs was upregulated compared to the controls. Increased levels of MALAT1 and NEAT1 could be associated with the downregulation of miR-30e-5p and miR-30a-5p expression in WBCs and plasma. We present novel data on the involvement of a possible regulatory axis lncRNAs/miR-30e/CHI3L1 in SSc and hypothesize that MALAT1 and NEAT1 could act as miR-30e-5p and miR-30a-5p decoys. This may be a reason for the increased serum levels of CHI3L1 in SSc patients.

New Insights into Profibrotic Myofibroblast Formation in Systemic Sclerosis: When the Vascular Wall Becomes the Enemy

In systemic sclerosis (SSc), abnormalities in microvessel morphology occur early and evolve into a distinctive vasculopathy that relentlessly advances in parallel with the development of tissue fibrosis orchestrated by myofibroblasts in nearly all affected organs. Our knowledge of the cellular and molecular mechanisms underlying such a unique relationship between SSc-related vasculopathy and fibrosis has profoundly changed over the last few years. Indeed, increasing evidence has suggested that endothelial-to-mesenchymal transition (EndoMT), a process in which profibrotic myofibroblasts originate from endothelial cells, may take center stage in SSc pathogenesis. While in arterioles and small arteries EndoMT may lead to the accumulation of myofibroblasts within the vessel wall and development of fibroproliferative vascular lesions, in capillary vessels it may instead result in vascular destruction and formation of myofibroblasts that migrate into the perivascular space with consequent tissue fibrosis and microvessel rarefaction, which are hallmarks of SSc. Besides endothelial cells, other vascular wall-resident cells, such as pericytes and vascular smooth muscle cells, may acquire a myofibroblast-like synthetic phenotype contributing to both SSc-related vascular dysfunction and fibrosis. A deeper understanding of the mechanisms underlying the differentiation of myofibroblasts inside the vessel wall provides the rationale for novel targeted therapeutic strategies for the treatment of SSc.

Prediction and primary prevention of major vascular complications in systemic sclerosis

OBJECTIVE

In Systemic Sclerosis (SSc), vasculopathy is the background of major vascular complications (MVCs), like digital ulcers (DUs), pulmonary arterial hypertension (PAH) and scleroderma renal crisis (SRC). We aimed to identify the predictors and to test the primary preventive effect of vasoactive/vasodilating drugs (VVD) for the development of MVCs in SSc MVCs-naïve patients.

METHODS

patients fulfilling the ACR/EULAR 2013 classification criteria for SSc without history of MVCs were eligible. Data about clinical manifestations, laboratory and instrumental assessments and treatments were retrospectively collected at baseline and latest available follow-up.

RESULTS

134 SSc patients were enrolled (mean age 56.5 years ± 14.2, females 88.1%, limited subset 61.9%, ACA positivity 60.4%). In a mean of 43 ± 19 months of follow-up 12 (9.0%) patients developed at least 1 MVC (10 DU, 2 PAH and 1 SRC). Dyspnoea and arthritis at baseline were independent predictors for MVCs development (p = 0.012, and p = 0.002 respectively). No primary preventive effect of VVD on MVCs development was found. However, sildenafil reduced the renal resistive index increase (p = 0.042) and alprostadil slowed the DLco decline (p = 0.029). Both iloprost and angiotensin-receptor blockers (ARBs) delayed MVCs development, while angiotensin converting enzyme inhibitors (ACEi) determined an earlier onset of such MCVs.

CONCLUSIONS

in SSc patients, our data confirm the role of arthritis and dyspnea as independent predictors of major vascular complications, in particular in MVCs-naïve patients. Prostanoids, sildenafil and ARBs, even in absence of a primary preventive action, might help in slowing disease progression and postponing the onset of MVCs.

The Relationship between Pulmonary Damage and Peripheral Vascular Manifestations in Systemic Sclerosis Patients

Systemic sclerosis (SSc) is an autoimmune disease, characterized by the presence of generalized vasculopathy and tissue fibrosis. Collagen vascular disorder in SSc is due to fibroblast and endothelial cell dysfunctions. This leads to collagen overproduction, vascular impairment and immune system abnormalities and, in the last stage, multi-organ damage. Thus, to avoid organ damage, which has a poor prognosis, all patients should be carefully evaluated and followed. This is particularly important in the initial disease phase, so as to facilitate early identification of any organ involvement and to allow for appropriate therapy. Pulmonary disease in SSc mainly involves interstitial lung disease (ILD) and pulmonary arterial hypertension (PAH). High-resolution computed tomography (HRCT) and pulmonary function tests (PFT) have been proposed to monitor parenchymal damage. Although transthoracic echocardiography is the most commonly used screening tool for PAH in SSc patients, definitive diagnosis necessitates confirmation by right heart catheterization (RHC). Moreover, some studies have demonstrated that nailfold videocapillaroscopy (NVC) provides an accurate evaluation of the microvascular damage in SSc and is able to predict internal organ involvement, such as lung impairment. This review provides an overview of the correlation between lung damage and microvascular involvement in SSc patients.

The Treatment of Lung Involvement in Systemic Sclerosis

Systemic sclerosis (SSc) patients are often affected by interstitial lung disease (ILD) and, although there have been recent treatment advances, it remains the leading cause of death among SSc, with a 10-year mortality up to 40%. African Americans and subjects with diffuse cutaneous SSc or anti-topoisomerase 1 antibodies are most commonly affected. Currently, early ILD diagnosis can be made, and it is pivotal to improve the prognosis. The diagnostic mainstay test for SSc-ILD is high-resolution computed tomography for the morphology and pulmonary function tests for the functional aspects. Treatment planning and intensity are guided by the disease severity and risk of progression. Traditionally, therapy has depended on combinations of immunosuppressants, particularly cyclophosphamide and mycophenolate mofetil, which can be supplemented by targeted biological and antifibrotic therapies. Benefits have been observed in trials on hematopoietic autologous stem cell transplantation for patients with progressive SSc, whilst lung transplantation is reserved for refractory SSc-ILD cases. Herein, recent advances in SSc-ILD treatment will be explored.