Interactions of autonomic nervous, neuroendocrine, and immune systems in rheumatoid arthritis

β2‑adrenergic receptor functionality and genotype in two different models of chronic inflammatory disease: Liver cirrhosis and osteoarthritis

The present study was designed to investigate the functional status of β2 adrenoceptors (β2AR) in two models of chronic inflammatory disease: liver cirrhosis (LC) and osteoarthritis (OA). The β2AR gene contains three single nucleotide polymorphisms at amino acid positions 16, 27 and 164. The aim of the present study was to investigate the potential influence of lymphocyte β2AR receptor functionality and genotype in LC and OA patients. Blood samples from cirrhotic patients (n=52, hepatic venous pressure gradient 13±4 mmHg, CHILD 7±2 and MELD 11±4 scores), OA patients (n=30, 84% Kellgren‑Lawrence severity 4 grade, 14% knee replacement joint) and healthy volunteers as control group (n=26) were analyzed. Peripheral blood mononuclear cells (PBMC) were isolated from whole blood and basal and isoproterenol induced adenylate cyclase activity (isoproterenol stimulus from 10‑9 to 10‑4 mM), and β2AR allelic variants (rs1042713, rs1042714, rs1800888) were determined. β2AR functionality was decreased in the two different models of chronic inflammatory disease studied, OA (50% vs. control) and LC (85% vs. control). In these patients, the strength of the β2AR response to adrenergic stimulation was very limited. Adrenergic modulation of PBMC function through the β2AR stimulus is decreased in chronic inflammatory processes including LC and OA, suggesting that the adrenergic system may be important in the development of these processes.

Childhood Residential and Agricultural Pesticide Exposures in Relation to Adult-Onset Rheumatoid Arthritis in Women

Farming and pesticide exposure may influence risk of rheumatoid arthritis (RA); the role of early-life pesticide exposure is unknown. The Sister Study includes a US national cohort of women aged 35-74 years (enrolled 2004-2009); we examined childhood pesticide exposure in women in this cohort with adult-onset RA. Cases (n = 424) were compared with 48,919 noncases. Data included pesticide use at the longest childhood residence through age 14 years, farm residence of at least 12 months with agricultural pesticide exposure through age 18 years, and maternal farm experience. Odds ratios and 95% confidence intervals were adjusted for age, race or ethnicity, education, smoking, and childhood socioeconomic factors. Cases with RA reported more frequent and direct (personal) residential pesticide use in childhood (for infrequent/indirect pesticide use, odds ratio (OR) = 1.1; for frequent/direct use, OR = 1.8; P for trend = 0.013). Compared with women without residential farm history, odds of having RA increased for those reporting a childhood-only farm residence with personal exposure to pesticides used on crops (OR = 1.8, 95% confidence interval: 1.1, 2.9) or livestock (OR = 2.0, 95% confidence interval: 1.2, 3.3). Our findings suggest adult-onset RA may be related to childhood exposure to residential and agricultural pesticides, and support further investigations of lifetime pesticide use in RA.

Substance P and Chronic Pain in Patients with Chronic Inflammation of Connective Tissue

Objective

Evidence suggests that substance P (SP) is involved in chronic joint inflammation, such as the pathogenesis of rheumatoid arthritis and osteoarthritis. The goal of the research was to evaluate the correlation between chronic pain and changes in the SP level in patients with chronic inflammation of the connective tissue.

Methods

Patients with osteoarthritis and rheumatoid arthritis were enrolled in this study. The relationship between chronic pain intensity and the serum SP concentration was evaluated in these groups of patients with osteoarthritis and rheumatoid arthritis.

Results

The results showed a positive correlation between the serum SP concentrations and chronic pain intensity.

Conclusions

1. The SP serum concentration was significantly different between the groups of patients with OA and RA. 2. There was a positive correlation between the serum SP concentration and chronic pain intensity in OA and RA patients.

Altered sympathetic-to-immune cell signaling via β₂-adrenergic receptors in adjuvant arthritis

Adjuvant-induced arthritic (AA) differentially affects norepinephrine concentrations in immune organs, and in vivo β-adrenergic receptor (β-AR) agonist treatment distinctly regulates ex vivo cytokine profiles in different immune organs. We examined the contribution of altered β-AR functioning in AA to understand these disparate findings. Twenty-one or 28 days after disease induction, we examined β₂-AR expression in spleen and draining lymph nodes (DLNs) for the arthritic limbs using radioligand binding and western blots and splenocyte β-AR-stimulated cAMP production using enzyme-linked immunoassay (EIA). During severe disease, β-AR agonists failed to induce splenocyte cAMP production, and β-AR affinity and density declined, indicating receptor desensitization and downregulation. Splenocyte β₂-AR phosphorylation (pβ₂-AR) by protein kinase A (pβ₂-AR_PKA) decreased in severe disease, and pβ₂-AR by G protein-coupled receptor kinases (pβ₂-AR_GRK) increased in chronic disease. Conversely, in DLN cells, pβ₂-AR_PKA rose during severe disease, but fell during chronic disease, and pβ₂-AR_GRK increased during both disease stages. A similar pβ₂-AR pattern in DLN cells with the mycobacterial cell wall component of complete Freund's adjuvant suggests that pattern recognition receptors (i.e., toll-like receptors) are important for DLN pβ₂-AR patterns. Collectively, our findings indicate lymphoid organ- and disease stage-specific sympathetic dysregulation, possibly explaining immune compartment-specific differences in β₂-AR-mediated regulation of cytokine production in AA and rheumatoid arthritis.

Adrenergic modulation of immune cells: an update

Sympathoadrenergic pathways are crucial to the communication between the nervous system and the immune system. The present review addresses emerging issues in the adrenergic modulation of immune cells, including: the specific pattern of adrenoceptor expression on immune cells and their role and changes upon cell differentiation and activation; the production and utilization of noradrenaline and adrenaline by immune cells themselves; the dysregulation of adrenergic immune mechanisms in disease and their potential as novel therapeutic targets. A wide array of sympathoadrenergic therapeutics is currently used for non-immune indications, and could represent an attractive source of non-conventional immunomodulating agents.

[Opioids in musculoskeletal pain]

Opioids are the most potent analgesics available and are well established for the treatment of severe acute, surgical and cancer pain. Due to their high effectiveness, their use in chronic non-cancer pain (CNCP) is being propagated. However, the use of opioids is still controversial due to their side effects, such as tolerance, addiction or withdrawal, and administrative difficulties associated with their prescription. Chronic rheumatic diseases, in particular low back pain and arthritis, are the leading causes of CNCP. The present article provides a brief overview of the role of opioids in chronic rheumatic diseases, pointing out that a national guideline for opioid use in CNCP is expected at the end of 2008. Furthermore, the peripheral effects of opioids on pain and inflammation in rheumatic diseases will be outlined.

Beta2-adrenergic receptors mediate the differential effects of catecholamines on cytokine production of PBMC

We determined characteristics of beta2-adrenergic receptors (beta2R) on peripheral blood mononuclear cells (PBMC) and cytokine production after mitogenic stimulation and coincubation with catecholamines. PBMCs were stimulated with interleukin-2 (IL-2), tetanus toxoid (TT), anti-CD3 antibody, or phytohemagglutinin (PHA). The cytokines interferon-gamma (IFN-gamma), IL-4, and IL-6 were determined by ELISA following coincubation with high-dose (10(-5) M) and low-dose (10(-9) M) epinephrine (EPI) and norepinephrine (NE). Intracellular IFN-gamma and IL-4 were studied by FACS analysis. The beta2R density was investigated using a radioligand binding assay. The stimuli induced various cytokine profiles in PBMCs. Synthesis of IFN-gamma was induced by all mitogens and could be suppressed by catecholamines (26%-85% reduction). In PHA-stimulated PBMCs, IL-4 synthesis was decreased by high-dose catecholamines (24%-28% reduction). Adding a beta-blocking agent attenuated most catecholamine effects. A highly significant negative correlation between the density of beta2R with IFN-gamma and IL-6 levels of PHA-activated PBMCs (r = -0.88 to -0.96, p < 0.01-< 0.001) was observed. The results indicate that the density of beta2R on PBMC plays a role in mediating the differential catecholamine effects on cytokine production of PBMC. Furthermore, changes in cytokine expression induced by catecholamines favor Th2 responses.

Styles of emotion regulation and their associations with perceived health in patients with rheumatoid arthritis

BACKGROUND

Patients with rheumatoid arthritis face the challenge of adjusting to adverse health consequences and accompanying emotions. Styles of emotion regulation may affect health.

PURPOSE

The objective is to examine associations between styles of emotion regulation and perceived health, consisting of psychological well-being, social functioning, physical functioning, and disease activity.

METHODS

Principal component analysis was used to summarize styles of emotion regulation of 335 patients with rheumatoid arthritis. Relationships between emotion regulation and perceived health were examined with structural equation modeling.

RESULTS

Four styles of emotion regulation were identified: ambiguity, control, orientation, and expression. Ambiguity and control were mutually correlated, as were orientation and expression. Styles of emotion regulation were not uniquely related to perceived physical functioning and disease activity. Emotional ambiguity and orientation were related to poorer, whereas expression and control were related to more favorable psychological well-being and social functioning.

CONCLUSIONS

Our cross-sectional study suggests that emotion regulation is not of direct importance for perceived somatic health of patients with rheumatoid arthritis, but it may be of importance for psychological well-being and social functioning, and perhaps through this route for somatic health. The more conscious and controlled aspects of control and expression are positively related to psychosocial health, and the more unconscious automatic aspects of ambiguity and orientation are negatively related. Changing emotion regulation will potentially affect psychosocial health. It would be worthwhile to verify this possibility in prospective research.

Neuroendocrine-immune relationships between emotion regulation and health in patients with rheumatoid arthritis

OBJECTIVES

Emotion regulation is hypothesized to be related to health through neuroendocrine-immune changes. This study examined the role of the neuroendocrine variables 24-h urinary cortisol and noradrenaline, and the immune variable serum interleukin 6 as mediators between emotion regulation styles and health (perceived health and disease activity: erythrocyte sedimentation rate (ESR) and Thompson joint score).

METHODS

Sixty patients with rheumatoid arthritis (mean age 59.0+/-11.2 yr; 38 female) participated.

RESULTS

Emotion regulation was not associated with immune functioning or disease activity, but it was somewhat related to neuroendocrine functioning: one of the emotion regulation styles, ambiguity, was related to noradrenaline in women (r = 0.39) but not in men. The indicators of neuroendocrine functioning (cortisol and noradrenaline) were correlated (r = 0.40), as were indicators of immune functioning (interleukin 6) and inflammatory activity (ESR; r = 0.53), but analyses did not indicate a role of these physiological variables in mediating between emotion regulation and health: neuroendocrine variables were not related to interleukin 6 or ESR, and none of the physiological parameters was correlated with joint score or perceived health.

CONCLUSIONS

To examine whether the proposed mediational processes apply to individual patients, a longitudinal within-subjects design is needed. In our cross-sectional study, emotion regulation was somewhat related to neuroendocrine functioning, but our study did not uncover a potential mediational role of cortisol, noradrenaline or interleukin 6 in the relationship between emotion regulation and health in rheumatoid arthritis.

Gastrin-releasing peptide, substance P and cytokines in rheumatoid arthritis

Many studies have shown that modulation of cytokine function is effective in ameliorating symptoms of rheumatoid arthritis. Neuropeptides have recently been shown to have powerful effects on the production and release of cytokines and have also been shown to exert potent proinflammatory and anti-inflammatory effects in animal models of inflammatory diseases. An analysis of cytokine and neuropeptide content of synovial fluid from patients with rheumatoid arthritis has revealed a significant correlation between two neuropeptides, bombesin/gastrin-releasing peptide and substance P, and the proinflammatory cytokine interleukin-6 as well as the erythrocyte sedimentation rate. These findings provide further evidence for a role of neuropeptides and cytokines in the pathophysiology of rheumatoid arthritis, as well as suggesting additional approaches for the development of novel therapeutic interventions.

Low levels of dehydroepiandrosterone sulphate in plasma, and reduced sympathoadrenal response to hypoglycaemia in premenopausal women with rheumatoid arthritis

OBJECTIVES

To evaluate the function of the hypothalamic-pituitary-adrenal axis and sympathoadrenal system in premenopausal women with rheumatoid arthritis (RA).

METHODS

Insulin-induced hypoglycaemia (0.1 IU/kg) was produced in 15 glucocorticoid-naive patients with long term RA with low disease activity and in 14 healthy women matched for age and body mass index. Concentrations of glucose, adrenocorticotropic hormone (ACTH), cortisol, Delta4-androstenedione (ASD), dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulphate (DHEAS), 17alpha-hydroxyprogesterone (17OHP), epinephrine (EPI), norepinephrine (NE), interleukin 6 (IL6), and tumour necrosis factor alpha (TNFalpha) were analysed in plasma.

RESULTS

Patients had comparable responses of glucose, cortisol, ACTH, ASD, and 17OHP to hypoglycaemia, without any signs of hypothalamic insufficiency. Patients had lower basal DHEAS than controls (3.03 (0.37) micromol/l v 5.1 (0.9) micromol/l, respectively; p<0.05); borderline lower basal DHEA levels (p = 0.067); while the response of DHEA to hypoglycaemia was comparable to that of controls. Patients with RA had lower EPI (p = 0.005) and NE (p<0.001) responses to hypoglycaemia. TNFalpha and IL6 were higher (p<0.05) in patients with RA (TNFalpha 8 (2.8) pg/ml in RA v 1.1 (0.5) pg/ml in controls and IL6 15.1 (6.7) pg/ml v 1.4 (0.7) pg/ml).

CONCLUSIONS

Lower basal DHEAS levels, without concomitant differences or changes in DHEA, ASD, 17OHP, and cortisol responses to hypoglycaemia in patients with RA, indicate an isolated decrease in adrenal androgen production. Significantly lower responses of EPI and NE to hypoglycaemia may suggest sympathoadrenal hyporeactivity in patients with RA.

Search for disease-specific cardiovascular reactivity patterns: developing the methodology

Aberrations of CVR (cardiovascular reactivity), an expression of autonomic function, lack specificity for a particular disorder. Recently, a CVR pattern particular to chronic fatigue syndrome has been observed. In the present study, we aimed to develop methodologies for assessing disease-specific CVR patterns. As a prototype, a population of 50 consecutive patients with FMF (familial Mediterranean fever) was studied and compared with control populations. A 10 min supine/30 min head-up tilt test with recording of the heart rate and blood pressure or the pulse transit time was performed. Five studies were conducted applying different methods. In each study, statistical analysis identified independent predictors of CVR in FMF. Based on regression coefficients of these predictors, a linear DS (discriminant score) was computed for every subject. Each study established an equation to assess CVR, calculate DS for FMF and determine the sensitivity and specificity of the DS cut-off. In each of the five studies, abnormal CVR was observed in FMF patients. The best accuracy (88% sensitivity and 90.1% specificity for FMF) was obtained by a method based on beat-to-beat heart rate and pulse transit time recordings. Data was processed by fractal and recurrence quantitative analysis with recordings in FMF patients compared with a mixed control population. Identification of disease-specific CVR patterns was possible with the methodologies described in the present study. In FMF, disease-specific CVR may be explained by the interplay between neuroendocrine loops specific to FMF with cardiovascular homoeostatic mechanisms. Recognition of disease-specific CVR patterns may advance the understanding of homoeostatic mechanisms and have implications in clinical practice.

The effects of age, seropositivity and disease duration on autonomic cardiovascular reflexes in patients with rheumatoid arthritis

Previous studies have shown that autonomic cardiovascular reflexes (ACRs) are impaired in rheumatoid arthritis (RA) and in old age. To investigate the integrity of ACRs in patients with RA, with reference to age, duration of disease and rheumatoid factor (RF) positivity, we conducted a prospective open study of 62 RA outpatients (age 38-84) and 41 healthy controls (age 22-82) using five standard tests of ACR function. Patients of all ages with RA were found to have blunted ACRs when compared with younger controls, though this effect was subclinical. Older RA patients did not have significantly more ACR impairment than older controls. There was a tendency to greater impairment of ACRs in RA patients with a positive RF. The age-associated changes in ACRs in normal subjects are similar to those seen in RA patients of all ages. The effects of RA and age on ACRs do not appear to be additive.

Patterns of cardiovascular reactivity in disease diagnosis

BACKGROUND

Aberrations of cardiovascular reactivity (CVR), an expression of autonomic function, occur in a number of clinical conditions, but lack specificity for a particular disorder. Recently, a CVR pattern particular to chronic fatigue syndrome was observed.

AIM

To assess whether specific CVR patterns can be described for other clinical conditions.

METHODS

Six groups of patients, matched for age and gender, were evaluated with a shortened head-up tilt test: patients with chronic fatigue syndrome (CFS) (n = 20), non-CFS fatigue (F) (n = 15), neurally-mediated syncope (SY) (n = 21), familial Mediterranean fever (FMF) (n = 17), psoriatic arthritis (PSOR) (n = 19) and healthy subjects (H) (n = 20). A 10-min supine phase was followed by recording 600 cardiac cycles on tilt (5-10 min). Beat-to-beat heart rate (HR) and pulse transit time (PTT) were measured. Results were analysed using conventional statistics, recurrence plot analysis and fractal analysis.

RESULTS

Multivariate analysis evaluated independent predictors of the CVR in each patient group vs. all other groups. Based on these predictors, equations were determined for a linear discriminant score (DS) for each group. The best sensitivities and specificities of the DS, consistent with disease-related phenotypes of CVR, were noted in the following groups: CFS, 90.0% and 60%; SY, 93.3% and 62.5%; FMF, 90.1% and 75.4%, respectively.

DISCUSSION

Pathological disturbances may alter cardiovascular reactivity. Our data support the existence of disease-related CVR phenotypes, with implications for pathogenesis and differential diagnosis.

CD44-stimulated human B cells express transcripts specifically involved in immunomodulation and inflammation as analyzed by DNA microarrays

A number of studies have implicated a role for the cell surface glycoprotein CD44 in several biologic events, such as lymphopoiesis, homing, lymphocyte activation, and apoptosis. We have earlier reported that signaling via CD44 on naive B cells in addition to B-cell receptor (BCR) and CD40 engagement generated a germinal center-like phenotype. To further characterize the global role of CD44 in B differentiation, we examined the expression profile of human B cells cultured in vitro in the presence or absence of CD44 ligation, together with anti-immunoglobulin (anti-Ig) and anti-CD40 antibodies. The data sets derived from DNA microarrays were analyzed using a novel statistical analysis scheme created to retrieve the most likely expression pattern of CD44 ligation. Our results show that genes such as interleukin-6 (IL-6), IL-1alpha, and beta(2)-adrenergic receptor (beta(2)-AR) were specifically up-regulated by CD44 ligation, suggesting a novel role for CD44 in immunoregulation and inflammation.

Neuroendocrinology of autoimmunity

The HPA axis is fundamental for long-term survival and protection from the ravages of autoimmune disease. Continuing investigations suggest that the hypothesis linking susceptibility to autoimmune disease and a hyporesponsive HPA axis is somewhat simplistic. Instead, data from a number of different human diseases and from preclinical studies in a variety of models have suggested a more complicated picture. Alterations in the diurnal rhythms of ACTH, cortisol, and immune parameters appear to be linked to severity of disease. The use of low doses of steroids timed to target disrupted diurnal immune system changes in patients with RA may reduce the unfortunate side effects of long-term steroid use. Studies in cancer patients have related alterations in diurnal cortisol to survival. Whether differences in individual cortisol profiles are predictive of a deterioration in symptoms of autoimmune disease remains to be established. Responsiveness of the HPA axis to subtle challenges such as the dexamethasone suppression test and the related dexamethasone-CRF test suggest that there are different sub-populations of patients with RA and MS and these may have confounded earlier, apparently contradictory, studies. These different responses may be related to the severity of the disease. That these HPA axis differences can be altered beneficially through the use of antidepressants, as has been shown in MS, may impact on future health care strategies. However, reports of negative developments in arthritis associated with SSRI use suggest that the SSRIs may be unsuitable under some circumstances. The link of behavioral differences to alterations in neurotransmitter changes associated with disease is intriguing and opens new avenues of research. These future studies will require input from neuroscientists, neuroendocrinologists, psychologists, and immunologists working with the clinical specialties already involved in treating patients with autoimmune disease. These multidisciplinary studies reflecting the increased importance of hormonal and neurotransmitter involvement with the immune system hold great promise for the future.

Can nerve damage disrupt neuroendocrine immune homeostasis? Leprosy as a case in point

The crucial clinical problem in leprosy is the occurrence of acute inflammatory episodes that lead to nerve damage, even after the infecting organisms have been killed by antibiotics. We suggest that the instability of these inflammatory sites is attributable to a disturbance of the role that nerves play in the regulation of inflammation. The destruction of sensory C fibers and sympathetic innervation will remove anti-inflammatory feedback circuits. Moreover, diminishing levels of neuropeptides and changes in the cytokine profile will affect the cortisol-sensitivity of infiltrating T cells, and modulate the cortisol-cortisone shuttle so that the inflammatory site becomes resistant to physiological levels of anti-inflammatory adrenocortical steroids.

Regulation of beta2-adrenergic receptors on CD4 and CD8 positive lymphocytes by cytokines in vitro

Increasing evidence points to a close relationship between the autonomic nervous system and the immune system. To further investigate mechanisms regulating beta2-adrenergic receptor (beta2R) expression in lymphocytes, the influence of cytokines on the density of beta2R on purified CD4+ and CD8+ lymphocytes was determined in vitro. beta2R were determined by means of a radioligand binding assay with (125I)iodocyanopindolol. CD4+ and CD8+ lymphocytes were incubated with catecholamines, interleukin 1beta (IL-1beta) and interleukin 2 (IL-2) for 6-72 h. The results demonstrate declining beta2R numbers on CD4+ and CD8+ lymphocytes in vitro augmented by epinephrine. IL-1beta has no effect on beta2R expression compared to medium. However, incubation with IL-2 resulted in an up-regulation of beta2R on CD8+ lymphocytes. Thus, the study demonstrates a differential regulation of beta2R on T-lymphocyte subpopulations with CD8+ lymphocytes being more susceptible to mechanisms of beta2R modulation than CD4+ lymphocytes. The findings further strengthen the concept of a close interplay between the autonomic nervous system and the immune system.

Neuroendocrine immune mechanisms in rheumatic diseases. An overview and future implications

A new physiopathogenetic paradigm may be proposed for RA and possibly its related systemic rheumatic diseases (i.e., mechanisms whereby multiple risk factors initially perturb the homeostasis of core physiologic components over an extended premorbid phase, which may progress to clinical disease in later decompensated stages). These complex interactive processes are likely to be individualized according to genetic, nongenomic somatic, developmental, behavioral, and environmental influences. Future research promises to further elucidate the roles of neuroendocrine mechanisms in the rheumatic diseases and offers promise for enhanced therapies and possible avenues for disease modification if not eventual prevention.

Hormonal and immunologic risk factors for the development of rheumatoid arthritis: an integrative physiopathogenetic perspective

Evidence indicates that women who are susceptible to premenopausal onset of RA and men each have identifiable risk factors or risk markers long before onset of the clinical disease. Accordingly, further definition of such predictive factors promises to identify persons who are susceptible to developing RA during preclinical phases. Like coronary artery disease, once risks for developing RA can be reliably quantitated, research in primary prevention should become a realistic objective. Disease prevention objectives are central to the public health strategy of the National Arthritis Action Plan and the US Public Health Service "Healthy People 2000" plan (2010 plan also proposed). The decade of arthritis and musculoskeletal diseases (2000-2010) offers an incentive to nurture a new paradigm of RA prevention. Further research in neuroendocrine, immunologic, and microvascular risk factors for the development of RA promises to unravel its complex physiopathogenetic mechanisms and permit identification of persons who are at high risk for developing this disease. Successful research in identifying reliable risk factors (or markers) can be expected to lead to prevention strategies. Effective programs in identifying persons susceptible to RA could lead to earlier control measures and significantly reduce the enormous burden of this common disease, which affects all segments of the population.