Serum neurotrophin profile in systemic sclerosis

Autonomic dysfunction in systemic sclerosis: A scoping review

INTRODUCTION

Over the years several lines of evidence have implied a pathological involvement of autonomic nervous system (ANS) in systemic sclerosis (SSc). However, the relationship between autonomic dysfunction and SSc is not yet fully understood. The aims of this scoping review were to map the research done in this field and inform future research to investigate pathogenic hypotheses of ANS involvement.

METHODS

We performed a scoping review of publications collected through a literature search of MEDLINE and Web of Science databases, looking for dysautonomia in SSc. We included original data from papers that addressed ANS involvement in SSc regarding pathogenesis, clinical presentation and diagnostic tools.

RESULTS

467 papers were identified, 109 studies were selected to be included in the present review, reporting data from a total of 2742 SSc patients. Cardiovascular system was the most extensively investigated, assessing heart rate variability with 24 h HolterECG or Ewing's autonomic tests. Important signs of dysautonomia were also found in digital vasculopathy, gastrointestinal system and SSc skin, assessed both with non-invasive techniques and histologically. Research hypotheses mainly regarding the relationship between sympathetic system - ischemia and the role of neurotrophins were then developed and discussed.

CONCLUSION

We described the currently available evidence on pathogenesis, clinical presentation and diagnostic assessment of dysautonomia in SSc patients. A strong influence of ANS deregulation on SSc clearly emerges from the literature. Future research is warranted to clarify the mechanisms and timing of autonomic dysfunction in SSc.

Cytokine signatures differentiate systemic sclerosis patients at high versus low risk for pulmonary arterial hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) affects approximately 10% of patients with systemic sclerosis (SSc) and is a leading cause of death. We sought to identify serum cytokine signatures that risk stratify SSc patients for this potentially fatal complication.

METHODS

Subjects at high risk for PAH and with incident PAH based on right heart catheterization (RHC) were enrolled in the multi-center prospective registry, Pulmonary Hypertension Assessment and Recognition of Outcomes in Scleroderma (PHAROS). Low-risk SSc patients were enrolled at Stanford and had normal pulmonary function test and echocardiogram parameters. Serum was available from 71 high-risk patients, 81 incident PAH patients, 10 low-risk patients, and 20 healthy controls (HC). Custom 14- and 65-plex arrays were used for cytokine analysis. Cytokine expression was compared between patient groups by principal component analysis and Tukey's test result. A multiple hypotheses corrected p value <0.05 was considered significant.

RESULTS

Exploratory analysis using principal components showed unique clustering for each patient group. There was a significant difference in cytokine expression in at least one group comparison for every cytokine. Overall, there was very little difference in cytokine expression comparing high-risk and PAH patient groups; however, these groups had substantially different cytokine profiles compared to low-risk patients and HC.

CONCLUSION

These data suggest that cytokine profiles can distinguish SSc patients who are at high-risk for or have PAH from SSc patients who may be at lower risk for PAH and HC. However, high-risk and PAH patients had very similar cytokine profiles, suggesting that these patients are on a disease continuum.

Brain-derived neurotrophic factor in autoimmune inflammatory diseases (Review)

Numerous recent studies reported that brain-derived neurotrophic factor (BDNF) also exists in the peripheral blood to regulate the proliferation, differentiation and survival of lymphocytes. Besides the role of BDNF in neuron repair, circulatory BDNF also enhances the proliferation and reduces apoptosis of lymphocytes. Peripheral lymphocytes express both BDNF and its receptors. Increasing evidence has indicated that altered BDNF serum levels significantly affect patients with autoimmune inflammatory diseases and may also be linked to the pathogenesis of diseases. For instance, systemic lupus erythematosus, an autoimmune inflammatory disease involving multiple organs, is frequently linked to altered B lymphocyte function, imbalance of T-cell subpopulations and loss of immune tolerance, which dysregulates the immune regulatory network with excessive secretion of inflammatory cytokines. The present review summarized studies that suggest a potential link between circulatory BDNF and autoimmune inflammatory diseases.

Serum BDNF and cognitive dysfunction in SLE: findings from a cohort of 111 patients

OBJECTIVE

The association between brain-derived neurotrophic factor (BDNF) and neuropsychiatric systemic lupus erythematosus (NPSLE) is controversial in the literature. Cognitive dysfunction (CD) is a common, underdiagnosed NPSLE manifestation, but its pathophysiology is unknown. Thus, we investigate serum BDNF as a potential biomarker of CD in a cohort of SLE patients.

METHODS

We included 63 SLE patients, 48 NPSLE, and 57 age- and gender-matched controls (CON). All participants underwent neuropsychological assessment. Data on cardiovascular comorbidities, SLE disease activity index (SLEDAI), and Systemic Lupus International Collaborating Clinics damage index (SLICC-DI) were compiled. Multiple regression analyses evaluated predictors of serum BDNF levels.

RESULTS

Serum BDNF levels were lower in SLE and NPSLE patients than in CON (SLE 800.4 ± 502.7 vs. NPSLE 779.7 ± 426.3 vs. CON 1,345.5 ng/mL ± 438.4; p < 0.001). In addition, hypertension (B: - 192.5, SE: 84.3, 95% CI: - 359.7 to - 25.3, p = 0.024) and SLICC-DI score (B: - 75.9, SE: 27.2, 95% CI: - 129.8 to - 22, p = 0.006) were predictors of serum BDNF levels in SLE. There was no relation between BDNF levels and CD.

CONCLUSION

BDNF levels are lower in SLE patients than CON and inversely associated with hypertension and SLICC-DI scores. No association between BDNF levels and CD or NPSLE was observed in this cohort. These findings indicate that BDNF may be associated with overall burden in SLE rather than specific manifestations such as cognition impairment. Key Points • BDNF is associated with an overall burden in SLE rather than specific manifestations such as cognition dysfunction. • BDNF levels are reduced in patients with SLE, and higher SLICC-DI scores and hypertension are independent predictors of lower serum BDNF levels. • The cognitive dysfunction rate is elevated (46%) among Brazilian SLE patients.

Seasonal Expression of NGF and Its Cognate Receptors in the Ovaries of Grey Squirrels (Sciurus carolinensis)

Simple Summary

Invasive alien species pose a significant threat to biodiversity, as once they have adapted to their new environment, they cause the reduction and even extinction of native species. In this framework, the American grey squirrel (Sciurus carolinensis) poses a serious threat to the European red species squirrel (Sciurus vulgaris), especially in the Umbria region of Italy. In fact, an invasive grey squirrel population has adapted well to the Umbrian territory, showing high reproductive success. In addition to its role in the development of the vertebrate nervous system, nerve growth factor (NGF) has recently been found to play an important role in reproduction. In order to investigate the reproductive physiology of female grey squirrels, the ovarian presence, distribution, and gene expression of NGF and its cognate receptors were evaluated during both breeding and nonbreeding seasons. The presence and gene expression of this system at the ovarian level, mainly during the breeding season, confirm the possible involvement of NGF and its receptors in the gonadal activity of this invasive grey squirrel population.

Abstract

The grey squirrel is an invasive alien species that seriously threatens the conservation of the native red squirrel species. With the aim of characterizing the reproductive physiology of this species due to its great reproductive success, the function of the ovarian nerve growth factor (NGF) system was analyzed in a grey squirrel population living in central Italy. During the breeding and nonbreeding seasons, the ovarian presence, distribution, and gene expression of NGF, neurotrophic tyrosine kinase receptor 1 (NTRK1), and nerve growth factor receptor (NGFR), as well as NGF plasma concentrations, were evaluated in female grey squirrels. NGF was found in the luteal cells and in the thecal and granulosa cells of follicles, while NTRK1 and NGFR were only observed in follicular thecal and granulosa cells. NGF and NGFR transcripts were almost two-fold greater during the breeding season, while no seasonal differences were observed in NTRK1 gene expression. During the breeding season, NGFR was more expressed than NTRK1. Moreover, no changes were observed in NGF plasma levels during the reproductive cycle. The NGF system seems to be involved in regulating the ovarian cycle mainly via local modulation of NGF/NGFR, thus playing a role in the reproductive physiology of this grey squirrel population.

Peripheral blood brain-derived neurotrophic factor level and tyrosine kinase B expression on T lymphocytes in systemic lupus erythematosus: Implications for systemic involvement

OBJECTIVE

Brain-derived neurotrophic factor (BDNF) has been reported to be involved in the pathogenesis of autoimmune diseases and tyrosine kinase B (TrkB) is the specific receptor for BDNF. Our aim in this study was to investigate serum BDNF level and TrkB expression on peripheral blood T cell surface in patients with systemic lupus erythematosus (SLE) and explore potential relationship between serum BDNF and SLE.

METHODS

Samples from fifty SLE patients and thirty healthy controls were evaluated. Serum BDNF level was measured by enzyme-linked immunosorbent assay (ELISA) and the percentages of TrkB expression on the surface of CD3 + CD4 + and CD3 + CD8 + T lymphocytes were measured by flow cytometry. The SLE patients were divided into subgroups according to whether they exhibited brain, kidney or lung involvement, and whether the disease was active or inactive.

RESULTS

Serum BDNF levels in SLE patients were decreased when compared to the controls (p < 0.001). Comparing with the SLE individuals without systemic involvement, the BDNF levels were decreased in SLE patients with lupus nephritis (p = 0.042) and in SLE patients with neuropsychiatric manifestations (p = 0.04). On the other hand, the BDNF level was significantly increased in the inactive SLE group (p < 0.001) compared to the active SLE group. In addition, the percentages of TrkB expression on CD3 + CD4 + and CD3 + CD8 + T cell surface in SLE were significantly higher (p < 0.001; p < 0.001, respectively) than that in the controls.

CONCLUSIONS

Serum BDNF level combined with TrkB expression on T cell surface can reflect SLE activity. It is possible that BDNF may be used as a potential serological biomarker for disease activity of SLE. In addition, the significant decrease in serum BDNF level may imply systemic involvement of SLE, as well as, possibly, differentiate neuropsychiatric SLE from hormone-induced mental disorders.

Abnormalities in endothelial form of nitric oxide synthase is pathogenic in limited cutaneous systemic sclerosis

BACKGROUND

Limited cutaneous systemic sclerosis is one subtype of systemic sclerosis which is characterized by a prototypic multisystem fibrotic disorder.

OBJECTIVE

This study aimed to further investigate the pathological mechanism of limited cutaneous systemic sclerosis (lcSSc).

METHODS

The dataset GSE76807 generated from 10 lcSSc patients and five healthy controls was used. After the preprocessing of the original data, differentially expressed genes (DEGs) were identified and then performed functional analysis, protein-protein interaction (PPI) network and module analysis. Additionally, the transcription factors (TFs) and miRNAs which potentially regulating DEGs were identified and the co-regulatory network was constructed. Finally, DEGs targeted by current drugs were identified. Real-time quantitative PCR analyses of some DEGs in mice with lcSSc were performed.

RESULTS

Total 203 up-regulated and 189 down-regulated DEGs were obtained. The up-regulated genes were enriched in protein interactions at the synapses neuronal system, NCAM1 interactions, and CREB phosphorylation through the activation of CaMKII, while, cilium assembly, and endothelial form of nitric oxide synthase (eNOS) activation were enriched by down-regulated genes. SCRT2 and RABEP1 regulated by miR-218 were hub nodes in the network. DRD4 and GRIN2D were the main drug targets. RABEP1 and SSB were found lowly expressed in mice model with lcSSc.

CONCLUSION

Endothelial form of NOS activation would be suppressed, and the process of neuronal migration and outgrowth would be activated to participant in the pathological mechanism of lcSSc.

Prevalence and Clinical Associations of Antiphospholipid Antibodies in Systemic Sclerosis: New Data From a French Cross-Sectional Study, Systematic Review, and Meta-Analysis

Objectives: Antiphospholipid antibodies (aPL) can be present in the sera of systemic sclerosis (SSc) patients. This study aimed to determine the prevalence of aPL in a cross-sectional study of SSc patients, to assess their clinical associations, to perform a systematic review of published reports and a meta-analysis to estimate the worldwide prevalence of aPL in SSc. Methods: Two-hundred and forty-nine SSc patients were consecutively tested once for lupus anticoagulant (LA), anticardiolipin (aCL), and anti-β2glycoprotein I (anti-β2GpI) antibodies. Clinical associations with aPL positivity were studied using a logistic regression model. A systematic review of the literature was carried out in PubMed and Embase. Meta-analysis was performed using number of aPL positive (at least one of the three antibodies positive) and negative patients. Meta-regression was used to study potential factors explaining the heterogeneity between studies. Results: In our cross-sectional study, aPL positivity was found in 16 patients (prevalence 6.4%; 95%CI [3.8-10.4]). In multivariate analysis, there was a significant association between aPL positivity and venous thrombosis (VT) (OR 6.25 [1.18-33.00]; p = 0.028) and miscarriage (OR 5.43; 95%CI [1.31-22.13]; p = 0.017). Twenty-four studies were included in the meta-analysis, representing a total population of 3036 SSc patients. The overall pooled prevalence of aPL in SSc was 14% (9-20) with a high degree of heterogeneity among studies. Conclusion: This study found a prevalence of aPL positivity in our SSc population of 6.4% (3.8-10.4) and an overall worldwide pooled prevalence of 14% (9-20). In our SSc population, aPL positivity was associated with VT and miscarriage. These data provide additional insights into the role of aPL in the vasculopathy observed in SSc.

Changes in serum NGF levels after the exercise load in dogs: a pilot study

Serum nerve growth factor (NGF) levels are increased by the external stress in mice, humans and horses; however, similar variations have been unclear in dogs. Since dogs are usually subjected to conditions of work, exercise and activity as important partners of humans, we measured serum NGF levels post-exercise and compared them with serum cortisol levels, as a biomarker of physical stress. Serum cortisol levels were immediately elevated post-exercise and returned to basal levels within 1 hr. On the other hand, serum NGF levels were significantly increased 1 hr post-exercise and gradually returned to basal levels. Further research is necessary; nevertheless, we have demonstrated for the first time that serum NGF levels respond to exercise stress in dogs.

Raynaud's phenomenon: new aspects of pathogenesis and the role of nailfold videocapillaroscopy

Raynaud's phenomenon (RP) refers to paroxysmal pallor or cyanosis of the digits of the hands or feet and, infrequently, the tips of the nose or ears (acral parts) owing to cold-induced vasoconstriction of the digital arteries, precapillary arterioles, and cutaneous arteriovenous shunts.

Raynaud's phenomenon reflects an exaggeration of normal central and local vasomotor responses to cold or emotion. Raynaud's phenomenon has been classified as primary or secondary, depending on whether it occurs as an isolated condition or is associated mainly with a connective tissue disease.

Dysregulation of autonomic and sensitive nerve fibers, functional and structural vessel changes, and intravascular alterations can be observed in the pathogenesis of RP.

Nailfold videocapillaroscopy (NVC) is the best non-invasive and repetitive diagnostic technique for detecting morpho-functional changes in the microcirculation. Nailfold videocapillaroscopy is accepted in early diagnosis and monitoring of primary and secondary RP.

Serum nerve grow factor and brain-derived neurotrophic factor profiles in Sjögren's syndrome concomitant with interstitial lung disease

The aim of this study is to investigate the serum levels and clinical significance of nerve grow factor (NGF) and brain-derived neurotrophic factor (BDNF) in Sjogren's syndrome (SS) with interstitial lung disease (ILD). Fifty two untreated patients with SS were enrolled in the study. Of them, 25 patients only displayed salivary glands damage and/or lacrimal gland injury (simple SS group). The other 27 patients were lacrimal and/or salivary gland involvement as well as being concomitant only with intestinal lung disease (ILD group). Twenty-five serum samples from healthy volunteers were examined as controls. We measure serum NGF and BDNF levels by ELISA and correlate them with clinical data. Serum NGF levels were significantly higher in ILD patients (372 ± 129 pg/ml) and simple SS patients (293 ± 72 pg/ml) when compared with healthy controls (187 ± 47 pg/ml) (both p < 0.01). Significant difference were also found between the two patient groups (p < 0.01). In contrast, BDNF were significantly decreased in ILD patients (1,005 ± 143 pg/ml) when compared with either simple SS patients (1,204 ± 176 pg/ml, p < 0.01) or healthy controls (1,217 ± 155 pg/ml, p < 0.01). Correlation analysis showed NGF levels in ILD patient were positively correlated with serum levels of C-reactive protein and IgG (both p < 0.05). The abnormal NGF and BDNF in sera may be a potential character of ILD secondary to pSS.

Raynaud's phenomenon: from molecular pathogenesis to therapy

Raynaud's phenomenon (RP) is a well defined clinical syndrome characterized by recurrent episodes of digital vasospasm triggered by exposure to physical/chemical or emotional stress. RP has been classified as primary or secondary, depending on whether it occurs as an isolated condition (pRP) or is associated to an underlying disease, mainly a connective tissue disease (CTD-RP). In both cases, it manifests with unique "triple" (pallor, cyanosis and erythema), or "double" color changes. pRP is usually a benign condition, while sRP can evolve and be complicated by acral digital ulcers and gangrene, which may require surgical treatment. The pathogenesis of RP has not yet been entirely clarified, nor is it known whether autoantibodies have a role in RP. Even so, recent advances in our understanding of the pathophysiology have highlighted novel potential therapeutic targets. The aim of this review is to discuss the etiology, epidemiology, risk factors, clinical manifestations, recently disclosed pathogenic mechanisms underlying RP and their correlation with the available therapeutic options, focusing primarily on pRP and CTD-RP.

Serum and lymphocytic neurotrophins profiles in systemic lupus erythematosus: a case-control study

BACKGROUND

Neurotrophins play a central role in the development and maintenance of the nervous system. However, neurotrophins can also modulate B and T cell proliferation and activation, especially via autocrine loops. We hypothesized that both serum and lymphocytic neurotrophin levels may be deregulated in systemic Lupus erythematosus (SLE) and may reflect clinical symptoms of the disease.

METHODS

Neurotrophins in the serum (ELISA tests) and lymphocytes (flow cytometry) were measured in 26 SLE patients and 26 control subjects. Th1 (interferon-γ) and Th2 (IL-10) profiles and serum concentration of BAFF were assessed by ELISA in the SLE and control subjects.

FINDINGS

We have demonstrated that both NGF and BDNF serum levels are higher in SLE patients than healthy controls (p=0.003 and p<0.001), independently of Th1 or Th2 profiles. Enhanced serum NT-3 levels (p=0.003) were only found in severe lupus flares (i.e. SLEDAI ≥ 10) and significantly correlated with complement activation (decreased CH 50, Γ=-0.28, p=0.03). Furthermore, there was a negative correlation between serum NGF levels and the number of circulating T regulatory cells (Γ=0.48, p=0.01). In circulating B cells, production of both NGF and BDNF was greater in SLE patients than in healthy controls. In particular, the number of NGF-secreting B cells correlated with decreased complement levels (p=0.05). One month after SLE flare treatment, BDNF levels decreased; in contrast, NGF and NT-3 levels remained unchanged.

CONCLUSION

This study demonstrates that serum and B cell levels of both NGF and BDNF are increased in SLE, suggesting that the neurotrophin production pathway is deregulated in this disease. These results must be confirmed in a larger study with naive SLE patients, in order to avoid the potential confounding influence of prior immune-modulating treatments on neurotrophin levels.