Prevalence of Autonomic Neuropathy in Patients of Rheumatoid Arthritis and Its Correlation with Disease Severity

Neurologic Manifestations of Rheumatologic Disorders

OBJECTIVE

This article provides an overview of the neurologic manifestations of sarcoidosis and select rheumatologic disorders. An approach to the assessment and differential diagnosis of characteristic clinical presentations, including meningitis and vasculitis, is also reviewed. A review of treatment options is included as well as discussion of distinct areas of overlap, including rheumatologic disease in the setting of neuromyelitis spectrum disorder and demyelinating disease in the setting of tumor necrosis factor-α inhibitors.

LATEST DEVELOPMENTS

An increased understanding of the immune mechanisms involved in sarcoidosis and rheumatologic diseases has resulted in a greater diversity of therapeutic options for their treatment. Evidence directing the treatment of the central nervous system (CNS) manifestations of these same diseases is lacking, with a paucity of controlled trials.

ESSENTIAL POINTS

It is important to have a basic knowledge of the common CNS manifestations of rheumatologic diseases and sarcoidosis so that they can be recognized when encountered. In the context of many systemic inflammatory diseases, including systemic lupus erythematosus, IgG4-related disease, and sarcoidosis, CNS disease may be a presenting feature or occur without systemic manifestations of the disease, making familiarity with these diseases even more important.

Ventricular Tachycardia Has Mainly Non-Ischaemic Substrates in Patients with Autoimmune Rheumatic Diseases and a Preserved Ejection Fraction

Non-sustained ventricular tachycardia (NSVT) is a potentially lethal arrhythmia that is most commonly attributed to coronary artery disease. We hypothesised that among patients with NSVT and preserved ejection fraction, cardiovascular magnetic resonance (CMR) would identify a different proportion of ischaemic/non-ischaemic arrhythmogenic substrates in those with and without autoimmune rheumatic diseases (ARDs). In total, 80 consecutive patients (40 with ARDs, 40 with non-ARD-related cardiac pathology) with NSVT in the past 15 days and preserved left ventricular ejection fraction were examined using a 1.5-T system. Evaluated parameters included biventricular volumes/ejection fractions, T2 signal ratio, early/late gadolinium enhancement (EGE/LGE), T1 and T2 mapping and extracellular volume fraction (ECV). Mean age did not differ across groups, but patients with ARDs were more often women (32 (80%) vs. 15 (38%), p < 0.001). Biventricular systolic function, T2 signal ratio and EGE and LGE extent did not differ significantly between groups. Patients with ARDs had significantly higher median native T1 mapping (1078.5 (1049.0–1149.0) vs. 1041.5 (1014.0–1079.5), p = 0.003), higher ECV (31.0 (29.0–32.0) vs. 28.0 (26.5–30.0), p = 0.003) and higher T2 mapping (57.5 (54.0–61.0) vs. 52.0 (48.0–55.5), p = 0.001). In patients with ARDs, the distribution of cardiac fibrosis followed a predominantly non-ischaemic pattern, with ischaemic patterns being more common in those without ARDs (p < 0.001). After accounting for age and cardiovascular comorbidities, most findings remained unaffected, while only tissue characterisation indices remained significant after additionally correcting for sex. Patients with ARDs had a predominantly non-ischaemic myocardial scar pattern and showed evidence of diffuse inflammatory/ischaemic changes (elevated native T1-/T2-mapping and ECV values) independent of confounding factors.

Proarrhythmic electrophysiological and structural remodeling in rheumatoid arthritis

Chronic inflammatory disorders, including rheumatoid arthritis (RA), are associated with a twofold increase in the incidence of sudden cardiac death (SCD) compared with the healthy population. Although this is partly explained by an increased prevalence of coronary artery disease, growing evidence suggests that ischemia alone cannot completely account for the increased risk. The present review explores the mechanisms of cardiac electrophysiological remodeling in response to chronic inflammation in RA. In particular, it focuses on the roles of nonischemic structural remodeling, altered cardiac ionic currents, and autonomic nervous system dysfunction in ventricular arrhythmogenesis and SCD. It also explores whether common genetic elements predispose to both RA and SCD. Finally, it evaluates the potential dual effects of disease-modifying therapy in both diminishing and promoting the risk of ventricular arrhythmias and SCD.

Ganglionic Acetylcholine Receptor Antibodies and Autonomic Dysfunction in Autoimmune Rheumatic Diseases

Autonomic neuropathy has been reported in autoimmune rheumatic diseases (ARD) including Sjögren’s syndrome, systemic sclerosis, rheumatoid arthritis, and systemic lupus erythematosus. However, the pathophysiological mechanism underlying autonomic dysfunction remains unknown to researchers. On the other hand, autoimmune autonomic ganglionopathy (AAG) is an acquired immune-mediated disorder, which causes dysautonomia that is mediated by autoantibodies against ganglionic acetylcholine receptors (gAChRs). The purpose of this review was to describe the characteristics of autonomic disturbance through previous case reports and the functional tests used in these studies and address the importance of anti-gAChR antibodies. We have established luciferase immunoprecipitation systems to detect antibodies against gAChR in the past and determined the prevalence of gAChR antibodies in various autoimmune diseases including AAG and rheumatic diseases. Autonomic dysfunction, which affects lower parasympathetic and higher sympathetic activity, is usually observed in ARD. The anti-gAChR antibodies may play a crucial role in autonomic dysfunction observed in ARD. Further studies are necessary to determine whether anti-gAChR antibody levels are correlated with the severity of autonomic dysfunction in ARD.

Role of miR-9-5p in preventing peripheral neuropathy in patients with rheumatoid arthritis by targeting REST/miR-132 pathway

MicroRNAs (miRNAs) are found to play a key role in neural cell differentiation, peripheral nerve injury, and rheumatoid arthritis (RA). However, no study has yet been conducted highlighting their role in RA-induced peripheral neuropathy. Here, we investigated the role of miRNAs in RA-induced peripheral neuropathy. Levels of six miRNAs were detected in serum collected from 15 patients with RA and peripheral neuropathy and 16 patients with RA. In vitro, Schwann cells were treated with 0.1 ng/mL IL-6 and 20 ng/mL TNF-α. The expression level of miR-9-5p and its association with the repressor element-1 silencing transcription factor (REST) were investigated. The roles of miR-9-5p and REST in Schwann cell injury were examined after transfection of miR-9-5p mimics or REST siRNA. In patients with RA and peripheral neuropathy, serum miR-9-5p was significantly downregulated when compared with RA. In IL-6- and TNF-α-stimulated Schwann cells, apoptosis was induced, while the cell viability and level of miR-9-5p were inhibited. A significantly negative correlation was observed between miR-9-5p and REST. Transfection of miR-9-5p mimics and REST siRNA significantly reversed the inhibition of cell viability and induction of apoptosis caused by IL-6 and TNF-α. In addition, overexpression of miR-9-5p upregulated the expression of miR-132, miRNA targeting E1A binding protein EP300 (EEP300), phosphatase and tensin homolog (PTEN) and forkhead box O3 (FOXO3). These results showed that Schwann cells were protected by miR-9-5p from inflammatory damage by targeting REST/miR-132 pathway, which could provide new targets for treatment of RA-induced peripheral neuropathy.