Impaired angiogenesis as a feature of digital ulcers in systemic sclerosis

Digital ulcers associated with scleroderma: A major unmet medical need

Scleroderma or systemic sclerosis (SSc)-associated digital ischaemic complications, such as digital ulcers (SSc-DUs), appear relatively early during the disease course and are a major burden with substantial deterioration of quality of life. Expert rheumatologist and wound specialists have defined a DU; however, international application of the definition is still disorganised. Appearance of SSc-DUs is secondary to the onset of Raynaud's phenomenon and as a consequence, recommended first-line of treatment mainly includes vasodilators; however, many DUs are refractory to this treatment. Despite important practical issues, such as a lack of well-characterised SSc-wound healing animal model, significant efforts are needed to mechanistically understand the pathogenesis of SSc-DUs for developing clinically targetable disease modifying therapies.

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.

Body composition parameters in systemic sclerosis-a systematic review and meta-analysis

BACKGROUND

The aim of this systematic review and meta-analysis was to summarize current evidence regarding body composition (BC) in SSc in order to gain new insights and improve clinical care in the context of the nutritional status of SSc patients.

METHODS

The databases Web of Science, PubMed, Scopus and Cochrane Library were searched on 4 January 2023. Studies were included if they provided data regarding BC obtained by dual-energy X-ray absorptiometry (DXA) or bioelectrical impedance analysis (BIA) in patients with SSc and healthy controls (HC). The study design criteria for inclusion were cohort and observational studies. The risk of bias assessment was performed using the Newcastle-Ottawa scale. For meta-analysis, mean difference with a 95% confidence interval was obtained and all results were depicted as forest plots.

RESULTS

The number of retrieved publications was 593, of which nine were included in a random-effects meta-analysis totalling 489 SSc patients and 404 HC. Overall, significantly lower body mass index, lean mass (LM), fat mass (FM) and phase angle values were found in SSc patients when compared with HC. Furthermore, FM and LM were significantly lower in SSc patients when the DXA method was applied, whereas the same parameters were comparable between two groups of participants when BIA was applied.

CONCLUSION

Altered BC is characteristic of SSc patients indicating the need for regular nutritional status assessment in order to improve the quality of life and clinical care of patients with SSc.

Automated nailfold capillary density measurement method based on improved YOLOv5

Nailfold capillary density is an essential physiological parameter for analyzing nailfold health; however, clinical images of the nailfold are taken in many situations, and most clinicians subjectively analyze nailfold images. Therefore, based on the improved "you only look once v5" (YOLOv5) algorithm, this study proposes an automated method for measuring nailfold capillary density. The improved technique can effectively and rapidly detect distal capillaries by incorporating methods or structures such as 9mosaic, spatial pyramid pooling cross-stage partial construction, bilinear interpolation, and efficient intersection over union. First, the modified YOLOv5 algorithm was used to detect nailfold capillaries. Subsequently, the number of distal capillaries was filtered using the 90° method. Finally, the capillary density was calculated. The results showed that the Average Precision (AP)@0.5 value of the proposed approach reached 85.2 %, which was an improvement of 4.93 %, 5.24 %, and 107 % compared with the original YOLOv5, YOLOv6, and simple-faster rapid-region convolutional network (R-CNN), respectively. For different nailfold images, using the density calculated by nailfold experts as a benchmark, the calculated results of the proposed method were consistent with the manually calculated results and superior to those of the original YOLOv5.

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.

Towards a Unified Approach in Autoimmune Fibrotic Signalling Pathways

Autoimmunity is a chronic process resulting in inflammation, tissue damage, and subsequent tissue remodelling and organ fibrosis. In contrast to acute inflammatory reactions, pathogenic fibrosis typically results from the chronic inflammatory reactions characterizing autoimmune diseases. Despite having obvious aetiological and clinical outcome distinctions, most chronic autoimmune fibrotic disorders have in common a persistent and sustained production of growth factors, proteolytic enzymes, angiogenic factors, and fibrogenic cytokines, which together stimulate the deposition of connective tissue elements or epithelial to mesenchymal transformation (EMT) that progressively remodels and destroys normal tissue architecture leading to organ failure. Despite its enormous impact on human health, there are currently no approved treatments that directly target the molecular mechanisms of fibrosis. The primary goal of this review is to discuss the most recent identified mechanisms of chronic autoimmune diseases characterized by a fibrotic evolution with the aim to identify possible common and unique mechanisms of fibrogenesis that might be exploited in the development of effective antifibrotic therapies.

Autoantibodies against PIP4K2B and AKT3 Are Associated with Skin and Lung Fibrosis in Patients with Systemic Sclerosis

Systemic sclerosis (SSc) is a rare autoimmune systemic disease that leads to decreased survival and quality of life due to fibrosis, inflammation, and vascular damage in the skin and/or vital organs. Early diagnosis is crucial for clinical benefit in SSc patients. Our study aimed to identify autoantibodies in the plasma of SSc patients that are associated with fibrosis in SSc. Initially, we performed a proteome-wide screening on sample pools from SSc patients by untargeted autoantibody screening on a planar antigen array (including 42,000 antigens representing 18,000 unique proteins). The selection was complemented with proteins reported in the literature in the context of SSc. A targeted antigen bead array was then generated with protein fragments representing the selected proteins and used to screen 55 SSc plasma samples and 52 matched controls. We found eleven autoantibodies with a higher prevalence in SSc patients than in controls, eight of which bound to proteins associated with fibrosis. Combining these autoantibodies in a panel could lead to the subgrouping of SSc patients with fibrosis. Anti-Phosphatidylinositol-5-phosphate 4-kinase type 2 beta (PIP4K2B)- and anti-AKT Serine/Threonine Kinase 3 (AKT3)-antibodies should be further explored to confirm their association with skin and lung fibrosis in SSc patients.

Hybrid enhancement algorithm for nailfold images with large fields of view

Collecting and analyzing human nailfold images is an important component of studying human microcirculation. However, the large-field-of-view and high-resolution nailfold images captured by research microscopes introduce issues such as uneven brightness, low imaging contrast, and unclear vascular contours. To overcome these issues, this paper proposes a hybrid enhancement algorithm for nailfold images with large fields of view. First, adaptive histogram equalization with limited contrast (Clahe) is used to redistribute gray levels to enhance the brightness and contrast of images. Next, nonlocal means denoising (NL-means) is used to remove the noise amplified by Clahe algorithm. Finally, unsharp masking (Usm) is used to enhance the edge contour information of nailfold blood vessels. Comparing the enhanced images reveals that the hybrid enhancement algorithm improves the brightness and contrast of the nailfold image, makes the nailfold vessel contour more obvious, and the image noise continues to remain small, and it obtains the best visual effect. It is superior to other algorithms in terms of objective indicators and subjective evaluation.

Current Trends in Vascular Biomarkers for Systemic Sclerosis: A Narrative Review

Systemic sclerosis (SSc, scleroderma) is a multifaceted rare connective tissue disease whose pathogenesis is dominated by immune dysregulation, small vessel vasculopathy, impaired angiogenesis, and both cutaneous and visceral fibrosis. Microvascular impairment represents the initial event of the disease, preceding fibrosis by months or years and accounting for the main disabling and/or life-threatening clinical manifestations, including telangiectasias, pitting scars, periungual microvascular abnormalities (e.g., giant capillaries, hemorrhages, avascular areas, ramified/bushy capillaries) clinically detectable by nailfold videocapillaroscopy, ischemic digital ulcers, pulmonary arterial hypertension, and scleroderma renal crisis. Despite a variety of available treatment options, treatment of SSc-related vascular disease remains problematic, even considering SSc etherogenity and the quite narrow therapeutic window. In this context, plenty of studies have highlighted the great usefulness in clinical practice of vascular biomarkers allowing clinicians to assess the evolution of the pathological process affecting the vessels, as well as to predict the prognosis and the response to therapy. The current narrative review provides an up-to-date overview of the main candidate vascular biomarkers that have been proposed for SSc, focusing on their main reported associations with characteristic clinical vascular features of the disease.

Endoglin and Systemic Sclerosis: A PRISMA-driven systematic review

Background

Systemic Sclerosis (SSc) is a rare autoimmune disease whose pathogenesis is still poorly understood. The Transforming Growth Factor β superfamily is considered pivotal and a crucial role has been suggested for the type III receptor, Endoglin (ENG). The aim of this systematic review is to investigate and combine the current clinical and molecular available data, to suggest novel hints for further studies.

Methods

We followed PRISMA guidelines; the search was performed on three databases (MEDLINE, Web of Science, Embase) in date November 2nd, 2021. Subsequent to the exclusion of duplicates, we applied as inclusion criteria: 1. focus on the relationship between ENG and SSc; 2. English language. As exclusion criteria: 1. ENG exclusively as a cellular biomarker; 2. no focus on ENG-SSc relationship; 3. review articles and 4. abstracts that did not add novel data. Eligibility was assessed independently by each author to reduce biases. We divided records into clinical and molecular works and subgrouped them by their study features and aim.

Results

We selected 25 original papers and 10 conference abstracts. Molecular studies included 6 articles and 4 abstracts, whereas clinical studies included 17 articles and 6 abstracts; 2 articles presented both characteristics. Molecular studies were focussed on ENG expression in different cell types, showing an altered ENG expression in SSc-affected cells. Clinical studies mainly suggested that different disease phenotypes can be related to peculiar disregulations in soluble ENG concentrations.

Discussion

Concerning the possible limits of our search, boolean operators in our strings might have been uneffective. However, the use of different strings in different databases should have reduced this issue at a minimum. Another bias can be represented by the selection step, in which we excluded many articles based on the role of Endoglin as a histological vascular marker rather than a signaling receptor. We tried to reduce this risk by performing the selection independently by each author and discussing disagreements. Our systematic review pointed out that ENG has a pivotal role in activating different TGFβ-stimulated pathways that can be crucial in SSc pathogenesis and progression.

Cellular and Molecular Diversity in Scleroderma

With the increasing armamentarium of high-throughput tools available at manageable cost, it is attractive and informative to determine the molecular underpinnings of patient heterogeneity in systemic sclerosis (SSc). Given the highly variable clinical outcomes of patients labelled with the same diagnosis, unravelling the cellular and molecular basis of disease heterogeneity will be crucial to predicting disease risk, stratifying management and ultimately informing a patient-centered precision medicine approach. Herein, we summarise the findings of the past several years in the fields of genomics, transcriptomics, and proteomics that contribute to unraveling the cellular and molecular heterogeneity of SSc. Expansion of these findings and their routine integration with quantitative analysis of histopathology and imaging studies into clinical care promise to inform a scientifically driven patient-centred personalized medicine approach to SSc in the near future.

Vascular Endothelial Growth Factor Biology and Its Potential as a Therapeutic Target in Rheumatic Diseases

Rheumatic diseases constitute a diversified group of diseases distinguished by arthritis and often involve other organs. The affected individual has low quality of life, productivity even life-threatening in some severe conditions. Moreover, they impose significant economic and social burdens. In recent years, the patient outcome has been improved significantly due to clearer comprehension of the pathology of rheumatic diseases and the effectiveness of "treat to target" therapies. However, the high cost and the adverse effects are the concerns and full remissions are not often observed. One of the main processes that contributes to the pathogenesis of rheumatic diseases is angiogenesis. Vascular endothelial growth factor (VEGF), a central mediator that regulates angiogenesis, has different isoforms and functions in various physiological processes. Increasing evidence suggests an association between the VEGF system and rheumatic diseases. Anti-VEGF and VEGF receptor (VEGFR) therapies have been used to treat several cancers and eye diseases. This review summarizes the current understanding of VEGF biology and its role in the context of rheumatic diseases, the contribution of VEGF bioavailability in the pathogenesis of rheumatic diseases, and the potential implications of therapeutic approaches targeting VEGF for these diseases.

Vascular biomarkers and digital ulcerations in systemic sclerosis: results from a randomized controlled trial of oral treprostinil (DISTOL-1)

INTRODUCTION

Although there is abundant evidence of vascular perturbation from studies of peripheral blood in systemic sclerosis (SSc), there are few data about the ability to use biomarkers of vascular injury and growth factors to predict vascular outcomes and response to therapy. We sought to explore the association between candidate vascular biomarkers and digital ulcerations (DU) in a clinical trial context.

METHODS

We examined 19 circulating vascular, angiogenic, and inflammatory biomarkers in 124 patients with scleroderma and DU who participated in a randomized controlled trial of oral treprostinil diolamine (ClinicalTrials.gov identifier NCT00775463). Correlation, regression, and random forest analyses were conducted to assess biomarker relationships in response to drug treatment.

RESULTS

Over the 20-week trial, 82 (66%) patients had their cardinal ulcer completely heal, 54 (44%) developed new ulcers, and 72 (58%) had complete healing of all ulcers; mean change in ulcer burden comparing week 20 with baseline was - 0.36 ± 1.70. Nineteen biomarkers were analyzed for their association and ability to predict clinical DU outcomes. After adjusting for multiple comparisons, no individual biomarker (baseline level, week 20 level, or change over time) was significantly associated with any of the clinical outcomes, suggesting that traditional vascular, angiogenic or inflammatory drivers are not predictive of ulcer fate.

CONCLUSIONS

The lack of strong response to any of the vascular, angiogenic, or inflammatory markers suggest that these pathways are not primary drivers in the development of DU clinical outcomes in a SSc population with prevalent DU.

KEY POINTS

• Currently we lack robust biomarkers to predict vascular outcomes or response to therapy in scleroderma patients with Raynaud's phenomenon.• Longitudinal assessment of vascular biomarkers in a clinical trial setting provides a unique opportunity to define biomarkers that predict vascular outcomes.• In a randomized controlled trial of oral treprostinil diolamine for treatment of scleroderma-associated digital ulcers, biomarkers involved in several vascular, inflammatory, and angiogenic pathways did not predict short-term clinical response to therapy or digital ulcer outcomes.• Further study of these and other biomarkers should be considered in Raynaud's clinical trials in scleroderma patients without prevalent digital ulcers.

Phase angle could be a marker of microvascular damage in systemic sclerosis

OBJECTIVES

Systemic sclerosis (SSc) is an autoimmune disease characterized by endothelial dysfunction with fibrosis of skin and internal organs. Integrity of the endothelial cell is important to its physiologic function such as production of angiogenetic factors. The aim of this study was to assess whether phase angle (PhA) is altered in patients with SSc and whether its values correlate with vascular endothelial growth factor (VEGF) and digital microvascular damage.

METHODS

Patients with SSc and matched healthy controls underwent VEGF determination and bioimpedentiometry (BIA) for PhA assessment. Clinical assessment, disease activity index (DAI), disease severity scale, and nailfold videocapillaroscopy (NCV) were performed in patients with SSc.

RESULTS

Fifty-five patients (46 women) with a mean age of 53.2 ± 13.7 y were studied. The mean value of VEGF was significantly higher in patients with SSc than in the healthy controls (240.3 ± 149.5 versus 139 ± 87.5; P = 0.035). The mean value of PhA was significantly lower in the patient grouop than in the healthy controls (4.51 ± 0.87 versus 5.22 ± 0.55; P < 0.0001). A significant positive correlation was found between VEGF and PhA (P = 0.009, beta coefficient = 1.48) in SSc patients. A negative correlation between VEGF and DAI (P = 0.048, β coefficient = 0.48) was found. PhA median value was significantly (P = 0.006) lower in patients with late pattern SSc (4.2 [2.5-5.3]). PhA median value was significantly (P < 0,0001) lower in patients with digital ulcers (DUs; 4.2 [2.5-5.3]) than in those without DUs (3.80 [2.50-5] versus 4.75 [2.80-7.3]). These data were confirmed in both female and male patients.

CONCLUSIONS

The evaluation of VEGF with PhA, NVC, and DUs could be useful to estimate cellular and microvascular damage in patients with SSc.

Association between baseline clinical and imaging findings and the development of digital ulcers in patients with systemic sclerosis

Objective

Systemic sclerosis (SSc) can lead to ischemic complications such as digital ulcers (DUs). The aim of the study was to find predictors of DUs by clinical and new imaging methods.

Patients and methods

All 79 SSc patients included in the study received a clinical, colour Doppler ultrasound (CDUS), fluorescence optical imaging (FOI) and capillaroscopy examination at baseline, and their capacity to predict new DU development was analysed in 76 patients at 12 months follow-up.

Results

Twenty-two of 76 patients (28.9%) developed new ulcers during follow-up (diffuse SSc 48.1%; limited SSc 18.4%). Receiver operating characteristic (ROC) curve analysis revealed an area under the curve of 0.7576 for DU development, with a specificity of 87% and a sensitivity of 54.6% (p = 0.0003, OR = 8.1 [95%CI 2.5–25.6]) at a cut-off of ≥ 21 points (ACR/EULAR classification criteria for SSc). Capillaroscopy and CDUS had high sensitivity (100% and 95.5%) but low specificity (28.9% and 22.2%) for ulcer occurrence when used alone, but better specificity (46.3%) when combined (OR = 18.1 [95%CI 2.3–144.4]; p = 0.0004). Using FOI, fingers with pathologic staining had a higher risk for new ulcer development in the same finger (p = 0.0153). General future DU (i.e. DU also in other fingers) was associated with a missing FOI signal in the right digit III at baseline (p = 0.048).

Conclusion

New imaging modalities can predict digital ulcer development in SSc patients with high sensitivity for capillaroscopy and CDUS and enhanced specificity when combined. A missing signal of FOI in the right digit III at baseline was associated with general future DU.

Position article and guidelines 2018 recommendations of the Brazilian Society of Rheumatology for the indication, interpretation and performance of nailfold capillaroscopy

Nailfold capillaroscopy (NFC) is a reproducible, simple, low-cost, and safe imaging technique used for morphological analysis of nail bed capillaries. It is considered to be extremely useful for the investigation of Raynaud's phenomenon and for the early diagnosis of systemic sclerosis (SSc). The capillaroscopic pattern typically associated with SSc, scleroderma ("SD") pattern, is characterized by dilated capillaries, microhemorrhages, avascular areas and/or capillary loss, and distortion of the capillary architecture. The aim of these recommendations is to provide orientation regarding the relevance of NFC, and to establish a consensus on the indications, nomenclature, the interpretation of NFC findings and the technical equipments that should be used. These recommendations were formulated based on a systematic literature review of studies included in the database MEDLINE (PubMed) without any time restriction.

Image enhancement effect on inter and intra-observer reliability of nailfold capillary assessment

BACKGROUND

Nailfold capillaroscopy (NC) is a diagnostic imaging technique that is used to assess the blood capillary network in the nailfold area. NC is routinely used for patients with microcirculation problems, such as systemic sclerosis and other connective tissue diseases. Experts commonly use subjective evaluation as a reference point in images of nailfold video capillaroscopy, so it is important to reduce the inherent ambiguities in human judgment and diagnosis. Image quality is an important factor that affects measurement error and assessment time of NC images.

OBJECTIVE

In this study, a new image enhancement technique was introduced and evaluated subjectively.

METHODS

In total, 475 nailfold video capillaroscopy images from 18 healthy subjects and 41 systemic lupus erythematosus patients were used. The images were randomly divided into two sets, one each with 275 and 200. Eight independent observers who were familiar with the capillaroscopy technique participated in this study. The set of 275 images was evaluated by three observers with the forced-choice pairwise comparison method. Elliptic broken line (EBL) was used to count the number of capillaries. The intra- and inter-observer reliability of the original and enhanced images was evaluated on 200 images by five observers.

RESULT

Except for eight images, all observers preferred the enhanced images in the visual quality comparison method. The intra-class correlation coefficient (ICC) of intra- and inter-observer reliability increased from 0.76-0.84 to 0.82-0.89, respectively, when using the enhancement method.

CONCLUSION

By improving the image quality, more capillary details will be visible, and an observer can document more details that may not be visible in the original image and can do so more efficiently.

Lumbar sympathectomy regulates vascular cell turnover in rat hindfoot plantar skin

BACKGROUND

Sympathetic denervation and impaired angiogenesis cause skin diseases. However, the relationship between the sympathetic nervous system and vascular cell turnover in normal skin remains unclear.

OBJECTIVE

To determine the effects of sympathetic denervation on vascular cell turnover in normal skin.

METHODS

Rats underwent bilateral L2-4 sympathetic trunk resection (sympathectomy group) or sham operation (control). Hindfoot plantar skin was analyzed 2 weeks and 3 months postoperatively.

RESULTS

Mural cell marker (α-smooth muscle actin; p < 0.001, and desmin; p = 0.047) expression decreased 2 weeks after sympathectomy, but recovered 3 months after sympathectomy (p > 0.05). CD31 levels were lower in the experimental group than in the control group at 2 weeks (p = 0.009), but not at 3 months. Von Willebrand factor, vascular endothelial growth factor, and angiopoietin-2 expression were not significantly different between the groups (p > 0.05). Angiopoietin-1 expression levels were higher in the experimental group than in the control group at 2 weeks (p = 0.035), but not at 3 months.

CONCLUSIONS

Lumbar sympathectomy regulates vascular cell turnover in rat hindfoot plantar skin by inhibiting mural cell proliferation and increasing angiopoietin-1 expression. Sympathetic nerves therefore play an important role in plantar skin vascular cell turnover.

Age-related modulation of angiogenesis-regulating factors in the swine meniscus

An in‐depth knowledge of the native meniscus morphology and biomechanics in its different areas is essential to develop an engineered tissue. Meniscus is characterized by a great regional variation in extracellular matrix components and in vascularization. Then, the aim of this work was to characterize the expression of factors involved in angiogenesis in different areas during meniscus maturation in pigs. The menisci were removed from the knee joints of neonatal, young and adult pigs, and they were divided into the inner, intermediate and outer areas. Vascular characterization and meniscal maturation were evaluated by immunohistochemistry and Western blot analysis. In particular, expression of the angiogenic factor Vascular Endothelial Growth Factor (VEGF) and the anti‐angiogenic marker Endostatin (ENDO) was analysed, as well as the vascular endothelial cadherin (Ve‐CAD). In addition, expression of Collagen II (COLL II) and SOX9 was examined, as markers of the fibro‐cartilaginous differentiation. Expression of VEGF and Ve‐CAD had a similar pattern in all animals, with a significant increase from the inner to the outer part of the meniscus. Pooling the zones, expression of both proteins was significantly higher in the neonatal meniscus than in young and adult menisci. Conversely, the young meniscus revealed a significantly higher expression of ENDO compared to the neonatal and adult ones. Analysis of tissue maturation markers showed an increase in COLL II and a decrease in SOX9 expression with age. These preliminary data highlight some of the changes that occur in the swine meniscus during growth, in particular the ensemble of regulatory factors involved in angiogenesis.

The role of endothelial cells in the vasculopathy of systemic sclerosis: A systematic review

INTRODUCTION

Systemic sclerosis (SSc) is an autoimmune connective tissue disorder characterized by fibroproliferative vasculopathy, immunological abnormalities and progressive fibrosis of multiple organs including the skin. In this study, all English speaking articles concerning the role of endothelial cells (ECs) in SSc vasculopathy and representing biomarkers are systematically reviewed and categorized according to endothelial cell (EC) (dys)function in SSc.

METHODS

A sensitive search on behalf of the EULAR study group on microcirculation in Rheumatic Diseases was developed in Pubmed, The Cochrane Library and Web of Science to identify articles on SSc vasculopathy and the role of ECs using the following Mesh terms: (systemic sclerosis OR scleroderma) AND pathogenesis AND (endothelial cells OR marker). All selected papers were read and discussed by two independent reviewers. The selection process was based on title, abstract and full text level. Additionally, both reviewers further searched the reference lists of the articles selected for reading on full text level for supplementary papers. These additional articles went through the same selection process.

RESULTS

In total 193 resulting articles were selected and the identified biomarkers were categorized according to description of EC (dys)function in SSc. The most representing and reliable biomarkers described by the selected articles were adhesion molecules for EC activation, anti-endothelial cell antibodies for EC apoptosis, vascular endothelial growth factor (VEGF), its receptor VEGFR-2 and endostatin for disturbed angiogenesis, endothelial progenitors cells for defective vasculogenesis, endothelin-1 for disturbed vascular tone control, Von Willebrand factor for coagulopathy and interleukin (IL)-33 for EC-immune system communication. Emerging, relatively new discovered biomarkers described in the selected articles, are VEGF₁₆₅b, IL-17A and the adipocytokines. Finally, myofibroblasts involved in tissue fibrosis in SSc can derive from ECs or epithelial cells through a process known as endothelial-to-mesenchymal transition.

CONCLUSION

This systematic review emphasizes the growing evidence that SSc is primarily a vascular disease where EC dysfunction is present and prominent in different aspects of cell survival (activation and apoptosis), angiogenesis and vasculogenesis and where disturbed interactions between ECs and various other cells contribute to SSc vasculopathy.