What are the new milestones in the pathogenesis of systemic sclerosis?

Peripheral cells from patients with systemic sclerosis disease co-expressing M1 and M2 monocyte/macrophage surface markers: Relation to the degree of skin involvement

The monocyte/macrophage lineage cells were found involved in the pathogenesis of systemic sclerosis (SSc) disease. The naïve macrophages are activated either to M1 cells with proinflammatory roles or to M2 cells that function to resolve inflammation with tissue repair. Recently, cells with dual phenotypes were detected in SSc disease. So, we aimed in this study to demonstrate different monocyte/macrophage phenotypes in peripheral cells from a group of Egyptian SSc patients, correlating percentages of these cells with the clinical findings in patients. The study participants comprised 41 patients with diffuse cutaneous SSc disease and 25 healthy individuals as controls. Clinical, radiological, and laboratory tests were conducted for SSc patients. Different phenotypes of the monocyte/macrophage subsets were identified in peripheral blood of patients and controls by flow cytometry for characteristic M1 (CD80, CD86, and TLR4) and M2 (CD204, CD163 and CD206) markers. SSc patients showed higher percentages of peripheral cells of the M1, M2, and mixed M1/M2 phenotypes within the monocyte/macrophage lineage compared to controls. Different cell phenotypes were associated significantly with the disease duration, modified Rodnan's score, the Medsger skin score, and the Medsger lung in SSc patients. Some cells with the M1/M2 phenotypes were higher in SSc patients with pitting scars, arthritis, and myalgia.

Investigation of the effectiveness of Tai Chi exercise program in patients with scleroderma: A randomized controlled study

BACKGROUND

and Purpose: There were studies showing the positive effects of Tai Chi on sleep, fatigue, endurance, balance, anxiety and depression in rheumatologic diseases. The aim of this study was to investigate the effects of Tai Chi exercise program on trunk endurance, balance, sleep, fatigue, anxiety and depression in patients with systemic sclerosis (SSc).

MATERIALS AND METHODS

28 patients were randomly divided into two groups as Tai Chi (n:14, 53.35 ± 10.86 years) and home exercise group (n:14, 52.64 ± 9.45 years). Trunk Lateral Endurance Test, Berg Balance Scale, Pittsburg Sleep Quality Index, Fatigue Severity Scale and Fatigue Impact Scale, Hospital Anxiety and Depression Scale was used for assesment. All evaluations were performed at baseline and at the end of the 10th week.

RESULTS

After training, a statistically significant difference was observed in all parameters in Tai Chi group (p:0.00); there was a significant difference in trunk endurance and sleep quality in the home exercise group (p:0.00-0.03) compared to pre-training. When the delta values between groups were compared, Tai Chi group was superior to home exercise group in all parameters except trunk endurance (p:0.00-0.01). No side effects were observed during the exercises.

CONCLUSION

As a result of our study; Tai Chi has a possitive effect on endurance, balance, sleep quality, fatique, anxiety and depression in patients with SSc. Tai Chi should be included in rehabilitation programs as a safe alternative type of exercise to improve trunk endurance, balance, sleep quality and reduce fatigue, anxiety and depression in patients with SSc.

Ventilation distribution as a contributor to the functional exercise capacity in patients with systemic sclerosis-associated interstitial lung disease without pulmonary hypertension

Phenotypic differences have been described between patients with systemic sclerosis (SSc)-associated interstitial lung disease (ILD) and SSc-associated pulmonary hypertension, including performance differences in the 6-min walk test (6MWT). Moreover, the correlations between the 6MWT and traditional pulmonary function tests (PFTs) are weak, indicating the need to search for new parameters that explain exercise performance. Thus, our objective was to evaluate the impact of ventilation distribution heterogeneity assessed by the nitrogen single-breath washout (N2SBW) test and peripheral muscle dysfunction on the exercise capacity in patients with SSc-ILD and limited involvement of the pulmonary parenchyma. In this cross-sectional study, 20 women with SSc-ILD and 20 matched controls underwent PFTs (including spirometry, diffusing capacity for carbon monoxide (DLco), and the N2SBW test) and performed the 6MWT and knee isometric dynamometry. The 6-min walking distance (6MWD, % predicted) was strongly correlated with the phase III slope of the single-breath nitrogen washout (phase III slopeN2SBW) (r=-0.753, P<0.0001) and reasonably correlated with the forced vital capacity (FVC) (r=0.466, P=0.008) and DLco (r=0.398, P=0.011). The peripheral oxygen saturation (SpO2) during exercise was not significantly correlated with any of the pulmonary or muscle function parameters. The phase III slopeN2SBW was the only predictive variable for the 6MWD, whereas quadriceps strength and FVC/DLco were predictive variables for SpO2. Ventilation distribution heterogeneity is one factor that contributes to a lower 6MWD in SSc-ILD patients. In addition, muscle dysfunction and abnormal lung diffusion at least partly explain the decreased SpO2 of these patients.

Dual αvβ3 and αvβ5 blockade attenuates fibrotic and vascular alterations in a murine model of systemic sclerosis

Systemic sclerosis (SSc) is a connective tissue disorder characterized by fibroblast activation and fibrosis of the skin and internal organs. Alterations in cell-integrin interaction are sufficient to initiate profibrotic processes. SSc fibroblasts express both αvβ3 and αvβ5 integrins and their activation induces myofibroblasts differentiation. The aim of the present study was to evaluate the effect of the anb3 and anb5 inhibitor, cilengitide, on the development of vascular and fibrotic changes in the chronic oxidant stress murine model of systemic sclerosis. SSc was induced in BALB/c mice by daily s.c. injections of HOCl for 6 weeks. Mice were randomized in three arms: HOCl alone (n=8), HOCl + Cilengitide (n=8), or Vehicle alone (n=8). Treatment with cilengitide 20 (mg/kg/i.p./day) was started 4 weeks after the first administration of HOCl and maintained throughout the remaining experimental period (2 weeks). Lung, skin, and heart fibrosis were evaluated by histology while kidney morphology by PAS staining. Collagen type I, focal adhesion kinase (FAK), and a-SMA were evaluated by immunostaining and p-FAK and TGF-β1 by Western blot and gene expression. Both cutaneous and pulmonary fibrosis induced by HOCl were attenuated by cilengitide treatment. Cilengitide administration reduced a-SMA, TGF-β1, and p-FAK expression and the increased deposition of fibrillar collagen in the heart and prevented glomeruli collapse in the kidneys. The inhibition of aνβ3 and aνβ5 integrin signaling prevented systemic fibrosis and renal vascular abnormalities in the reactive oxygen species model of SSc. Integrins aνβ3 and aνβ5 could prove useful as a therapeutic target in SSc.

Angiogenesis Dysregulation in the Pathogenesis of Systemic Sclerosis

Systemic sclerosis is a chronic autoimmune connective tissue disease characterized by vascular injury and fibrosis and by an impaired angiogenesis which cannot ensure an efficient vascular recovery. Vascular injury is responsible for hypoxia and tissual ischemia which are the primary triggers for angiogenesis and are not able to induce a compensatory angiogenesis. This review article is focused on current knowledge on the mechanisms responsible for angiogenesis dysregulation in systemic sclerosis.

Inhibition of angiogenesis by platelets in systemic sclerosis patients

INTRODUCTION

Systemic sclerosis (SSc) is a chronic autoimmune disease characterized by microvascular damage, inflammation, and fibrosis. It has become increasingly evident that platelets, beyond regulating hemostasis, are important in inflammation and innate immunity. Platelets may be an important source of proinflammatory and profibrotic cytokines in the vascular microenvironment. In this study, we sought to assess the contribution of platelet-derived factors in patients with SSc to the angiogenesis of human dermal microvascular endothelial cells (DMVECs) in a tubule formation assay and to characterize the secretion of profibrotic and proinflammatory cytokines in these platelets.

METHODS

We analyzed platelets obtained from 30 patients with SSc and 12 healthy control subjects. Angiogenesis was evaluated in vitro with a DMVEC tubule formation assay on Matrigel and platelet-derived angiogenic factors such as vascular endothelial growth factor (VEGF), 165b isoform (VEGF165b), and cytokine secretion was evaluated. Platelet serotonin content was also determined.

RESULTS

When DMVECs were incubated with SSc platelet releasates, tubule formation was significantly inhibited (p < 0.01, t test), and higher expression of endothelin-1 in these cells was observed compared with control subjects (p < 0.05, Mann-Whitney U test). In SSc platelet releasates, VEGF165b was significantly higher (p < 0.05, t test), and the VEGF165b/VEGF ratio was increased compared with that of control subjects. Higher secretion of transforming growth factor β (p < 0.01, t test) and CD40L (p < 0.01, t test) was observed compared with control subjects. Also, intraplatelet serotonin levels were lower in platelets obtained from patients with diffuse SSc compared with patients with limited SSc and control subjects (p < 0.05, t test).

CONCLUSIONS

Our findings suggest that antiangiogenic factors such as VEGF165b, together with proinflammatory and profibrotic factors secreted by platelets, can contribute to the progression of peripheral microvascular damage, defective vascular repair, and fibrosis in patients with SSc.

Involvement of collagen-binding heat shock protein 47 in scleroderma-associated fibrosis

Uncontrolled fibrosis of skin and internal organs is the main characteristic of scleroderma, and collagen is a major extracellular matrix protein that deposits in the fibrotic organs. As the chaperone of collagen, heat shock protein 47 (HSP47) is closely related with the development of fibrosis. To explore the potential function of HSP47 in the pathogenesis of scleroderma, the clinical, in vivo and in vitro studies were performed. In clinical, the increased mRNA level of HSP47 was observed in the skin fibroblasts and PBMC from scleroderma patients, and the enhanced protein level of HSP47 was also detected in the skin biopsy and plasma of the above patients. Unexpectedly, the enhanced levels of HSP47 were positively correlated with the presence of anti-centromere antibody in scleroderma patients. Moreover, a high expression of HSP47 was found in the skin lesion of BLM-induced scleroderma mouse model. Further in vitro studies demonstrated that HSP47 knockdown could block the intracellular and extracellular collagen over-productions induced by exogenous TGF-β. Therefore, the results in this study provide direct evidence that HSP47 is involved in the pathogenesis of scleroderma. The high expression of HSP47 can be detected in the circulatory system of scleroderma patients, indicating that HSP47 may become a pathological marker to assess the progression of scleroderma, and also explain the systemic fibrosis of scleroderma. Meanwhile, collagen over-expression is blocked by HSP47 knockdown, suggesting the possibility that HSP47 can be a potential therapeutic target for scleroderma.

Lower limb muscle strength is associated with functional performance and quality of life in patients with systemic sclerosis

Background:

Complaints of peripheral muscle weakness are quite common in patients with systemic sclerosis (SSc). It is likely that the muscle impairments may reduce the patients' exercise performance, which in turn may decrease their functional capacity and exert a direct impact on their quality of life.

Objectives:

To assess the peripheral and respiratory muscle strength in individuals with SSc and to investigate their correlation with the 6-min walk distance (6MWD) and quality of life measurements. Moreover, we aimed to characterize their nutritional status, pulmonary function, functional capacity, and quality of life compared to the controls.

Method:

The present cross-sectional study included 20 patients with SSc and 20 control subjects. All of the participants were subjected to isometric dynamometry, surface electromyography, bioelectrical impedance analysis, pulmonary function testing, and the 6-min walk test. Patients with SSc also responded to the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) and the Health Assessment Questionnaire Disability Index (HAQ-DI).

Results:

The individuals with SSc exhibited a reduction in quadriceps strength (p=0.0001), increased quadriceps fatigability (p=0.034), impaired pulmonary function, and a reduced 6MWD (p=0.0001) compared to the controls. Quadriceps strength was significantly correlated with the 6MWD (Rho=0.719; p=0.0004) and the HAQ-DI (Rho=-0.622; p=0.003). We also found significant correlations between quadriceps fatigability and maximal inspiratory (Rho=0.684; p=0.0009) and maximal expiratory (Rho=0.472; p=0.035) pressure.

Conclusions:

Patients with SSc exhibited reduced respiratory muscle and quadriceps strength and an increase in its fatigability. In these individuals, there was a relationship between quadriceps strength, functional capacity, and quality of life.

Impaired endothelium-mesenchymal stem cells cross-talk in systemic sclerosis: a link between vascular and fibrotic features

INTRODUCTION

To assess if an impaired cross-talk between endothelial cells (ECs) and perivascular/multipotent mesenchymal stem cells (MSCs) might induce a perturbation of vascular repair and leading to a phenotypic switch of MSC toward myofibroblast in Systemic Sclerosis (SSc).

METHODS

We investigated different angiogenic and profibrotic molecules in a tridimentional matrigel assay, performing co-cultures with endothelial cells (ECs) and bone marrow derived MSCs from patients and healthy controls (HC). After 48 hours of co-culture, cells were sorted and analyzed for mRNA and protein expression.

RESULTS

ECs-SSc showed a decreased tube formation ability which is not improved by co-cultures with different MSCs. After sorting, we showed: i. an increased production of vascular endothelial growth factor A (VEGF-A) in SSc-MSCs when co-cultured with SSc-ECs; ii. an increased level of transforming growth factor beta (TGF-β) and platelet growth factor BB (PDGF-BB) in SSc-ECs when co-cultured with both HC- and SSc-MSCs; iii. an increase of TGF-β, PDGF-R, alpha smooth muscle actin (α-SMA) and collagen 1 (Col1) in both HC- and SSc-MSCs when co-cultured with SSc-ECs.

CONCLUSION

We showed that during SSc, the ECs-MSCs crosstalk resulted in an altered expression of different molecules involved in the angiogenic processes, and mainly SSc-ECs seem to modulate the phenotypic switch of perivascular MSCs toward a myofibroblast population, thus supporting the fibrotic process.

Intensive aerobic and muscle endurance exercise in patients with systemic sclerosis: a pilot study

Background

No previous studies have examined the effect of intensive exercise in systemic sclerosis patients with pulmonary impairment. The objective of this study was to examine the effect of an eight-week intensive aerobic exercise and muscle endurance training program for patients with systemic sclerosis with 50–100% of forced vital capacity.

Methods

A single-subject experimental design with repeated systematic measures during a six week A-phase (non-interventional baseline period) and an eight week B-phase (exercise intervention period) was used. Three women and one man with median age 66 years and median disease duration of 3.5 years completed aerobic exercise corresponding to 15 on the Borg RPE scale (strenuous) and muscular endurance training three times/week. Physical capacity (six-minute walk test), aerobic capacity (submaximal treadmill test) and muscle endurance in shoulder and hip flexion (Functional Index 2) were assessed every other week throughout the 14-week study. Activity limitation (Health Assessment Questionnaire), quality of life (Short Form 36), Raynaud, Fatigue and Global Health during the recent week (Visual Analogue Scales) were assessed at weeks 0, 6, 14.

Results

Three participants improved significantly in muscular endurance, and two participants improved significantly or clinically relevant in aerobic capacity. All other variables remained unchanged, except for a trend towards reduced fatigue.

Conclusions

This eight week exercise program was largely successful with positive effects on aerobic capacity and muscle endurance.

Trial registration

Clinicaltrials.gov Identifier: NCT01813578

Targeting the PDGF signaling pathway in the treatment of non-malignant diseases

Platelet-derived growth factor (PDGF) is a family of mesenchymal mitogens with important functions during the embryonal development and in the control of tissue homeostasis in the adult. The PDGF isoforms exert their effects by binding to α-and β-tyrosine kinase receptors. Overactivity of PDGF signaling has been linked to the development of certain malignant and non-malignant diseases, including atherosclerosis and various fibrotic diseases. Different types of PDGF antagonists have been developed, including inhibitory monoclonal antibodies and DNA aptamers against PDGF isoforms and receptors, and receptor tyrosine kinase inhibitors. Beneficial effects have been recorded using such inhibitors in preclinical models and in patients with certain malignant as well as non-malignant diseases. The present communication summarizes the use of PDGF antagonists in the treatment of non-malignant diseases.

Vascular involvement in systemic sclerosis (scleroderma)

Systemic sclerosis (SSc) is an acquired multiorgan connective tissue disease with variable mortality and morbidity dictated by clinical subset type. The etiology of the basic disease and pathogenesis of the systemic autoimmunity, fibrosis, and fibroproliferative vasculopathy are unknown and debated. In this review, the spectrum of vascular abnormalities and the options currently available to treat the vascular manifestations of SSc are discussed. Also discussed is how the hallmark pathologies (ie, how autoimmunity, vasculopathy, and fibrosis of the disease) might be effected and interconnected with modulatory input from lysophospholipids, sphingosine 1-phosphate, and lysophosphatidic acid.

The vascular microenvironment and systemic sclerosis

The role of the vascular microenvironment in the pathogenesis Systemic Sclerosis (SSc) is appreciated clinically as Raynaud's syndrome with capillary nail bed change. This manifestation of vasculopathy is used diagnostically in both limited and diffuse cutaneous subsets of SSc, and is thought to precede fibrosis. The degree of subsequent fibrosis may also be determined by the vascular microenvironment. This paper describes why the vascular microenvironment might determine the degree of end-organ damage that occurs in SSc, with a focus on vascular cell senescence, endothelial progenitor cells (EPC) including multipotential mesenchymal stem cells (MSC), pericytes, and angiogenic monocytes. An explanation of the role of EPC, pericytes, and angiogenic monocytes is important to an understanding of SSc pathogenesis. An evolving understanding of the vascular microenvironment in SSc may allow directed treatment.