Endogenously produced catecholamines improve the regulatory function of TLR9-activated B cells.

The sympathetic nervous system (SNS) contributes to immune balance by promoting anti-inflammatory B cells. However, whether B cells possess a self-regulating mechanism by which they modulate regulatory B cell (Breg) function is not well understood. In this study, we investigated the ability of B cells to synthesize their own catecholamines upon stimulation with different B cell activators and found that expression of the enzyme tyrosine hydroxylase (TH), required to generate catecholamines, is up-regulated by Toll-like receptor (TLR)9. This TLR9-dependent expression of TH correlated with up-regulation of adrenergic receptors (ADRs), enhanced interleukin (IL)-10 production, and overexpression of the co-inhibitory ligands programmed death ligand 1 (PD-L1) and Fas ligand (FasL). Moreover, concomitant stimulation of ß1-3-ADRs together with a B cell receptor (BCR)/TLR9 stimulus clearly enhances the anti-inflammatory potential of Bregs to suppress CD4 T cells, a crucial population in the pathogenesis of autoimmune diseases, like rheumatoid arthritis (RA). Furthermore, TH up-regulation was also demonstrated in B cells during the course of collagen-induced arthritis (CIA), a mouse model for the investigation of RA. In conclusion, our data show that B cells possess an autonomous mechanism to modulate their regulatory function in an autocrine and/or paracrine manner. These findings help to better understand the function of B cells in the regulation of autoimmune diseases and the interplay of SNS.

Fibroblast-like synoviocytes preferentially induce terminal differentiation of IgD+ memory B cells instead of naïve B cells.

Rheumatoid arthritis (RA) is a systemic autoimmune disease driven by highly active autoantibody-producing B cells. Activation of B cells is maintained within ectopic germinal centres found in affected joints. Fibroblast-like synoviocytes (FLS) present in inflamed joints support B-cell survival, activation, and differentiation. CD27+ memory B cells and naive B cells show very different responses to activation, particularly by CD40 ligand (CD40L). We show that FLS-dependent activation of human B cells is dependent on interleukin-6 (IL-6) and CD40L. FLS have been shown to activate both naive and memory B cells. Whether the activating potential of FLS is different for naive and memory B cells has not been investigated. Our results suggest that FLS-induced activation of B cells is dependent on IL-6 and CD40L. While FLS are able to induce plasma cell differentiation, isotype switching, and antibody production in memory B cells, the ability of FLS to activate naive B cells is significantly lower.

Osteoarthritis patients exhibit an autonomic dysfunction with indirect sympathetic dominance.

BACKGROUND: Osteoarthritis (OA) is a chronic degenerative joint disease causing limited mobility and pain, with no curative treatment available. Recent in vivo studies suggested autonomic alterations during OA progression in patients, yet clinical evidence is scarce. Therefore, autonomic tone was analyzed in OA patients via heart rate variability (HRV) measurements. METHODS: Time-domain (SDRR, RMSSD, pRR50) and frequency-domain (LF, HF, LF/HF) HRV indices were determined to quantify sympathetic and parasympathetic activities. In addition, perceived stress, WOMAC pain as well as serum catecholamines, cortisol and dehydroepiandrosterone-sulphate (DHEA-S) were analyzed. The impact of the grade of disease (GoD) was evaluated by linear regression analysis and correlations with clinical data were performed. RESULTS: GoD significantly impacted the autonomic tone in OA patients. All time-domain parameters reflected slightly decreased HRV in early OA patients and significantly reduced HRV in late OA patients. Moreover, frequency-domain analysis revealed decreased HF and LF power in all OA patients, reflecting diminished parasympathetic and sympathetic activities. However, LF/HF ratio was significantly higher in early OA patients compared to late OA patients and implied a clear sympathetic dominance. Furthermore, OA patients perceived significantly higher chronic stress and WOMAC pain levels compared to healthy controls. Serum cortisol and cortisol/DHEA-S ratio significantly increased with GoD and positively correlated with WOMAC pain. In contrast, serum catecholamines only trended to increase with GoD and pain level. CONCLUSIONS: This prospective study provides compelling evidence of an autonomic dysfunction with indirect sympathetic dominance in early and late knee OA patients for the first time based on HRV analyses and further confirmed by serum stress hormone measurements. Increased sympathetic activity and chronic low-grade inflammation in OA as well as in its major comorbidities reinforce each other and might therefore create a vicious cycle. The observed autonomic alterations coupled with increased stress and pain levels highlight the potential of HRV as a prognostic marker. In addition, modulation of autonomic activity represents an attractive future therapeutic option.

Chronic Effects of the Sympathetic Nervous System in Inflammatory Models.

The immune system is embedded in a network of regulatory systems to keep homeostasis in case of an immunologic challenge. Neuroendocrine immunologic research has revealed several aspects of these interactions over the past decades, e.g., between the autonomic nervous system and the immune system. This review will focus on evidence revealing the role of the sympathetic nervous system (SNS) in chronic inflammation, like colitis, multiple sclerosis, systemic sclerosis, lupus erythematodes, and arthritis with a focus on animal models supported by human data. A theory of the contribution of the SNS in chronic inflammation will be presented that spans these disease entities. One major finding is the biphasic nature of the sympathetic contribution to inflammation, with proinflammatory effects until the point of disease outbreak and mainly anti-inflammatory influence thereafter. Since sympathetic nerve fibers are lost from sites of inflammation during inflammation, local cells and immune cells achieve the capability to endogenously produce catecholamines to fine-tune the inflammatory response independent of brain control. On a systemic level, it has been shown across models that the SNS is activated in inflammation as opposed to the parasympathetic nervous system. Permanent overactivity of the SNS contributes to many of the known disease sequelae. One goal of neuroendocrine immune research is defining new therapeutic targets. In this respect, it will be discussed that at least in arthritis, it might be beneficial to support ß-adrenergic and inhibit α-adrenergic activity besides restoring autonomic balance. Overall, in the clinical setting, we now need controlled interventional studies to successfully translate the theoretical knowledge into benefits for patients.

Anti-Inflammatory Effects of Cannabigerol in Rheumatoid Arthritis Synovial Fibroblasts and Peripheral Blood Mononuclear Cell Cultures Are Partly Mediated by TRPA1.

Since its medical legalization, cannabis preparations containing the major phytocannabinoids (cannabidiol (CBD) and δ9-tetrahydrocannabinol (THC)) have been used by patients with rheumatoid arthritis (RA) to alleviate pain and inflammation. However, minor cannabinoids such as cannabigerol (CBG) also demonstrated anti-inflammatory properties, but due to the lack of studies, they are not widely used. CBG binds several cellular target proteins such as cannabinoid and α2-adrenergic receptors, but it also ligates several members of the transient potential receptor (TRP) family with TRPA1 being the main target. TRPA1 is not only involved in nnociception, but it also protects cells from apoptosis under oxidative stress conditions. Therefore, modulation of TRPA1 signaling by CBG might be used to modulate disease activity in RA as this autoimmune disease is accompanied by oxidative stress and subsequent activation of pro-inflammatory pathways. Rheumatoid synovial fibroblasts (RASF) were stimulated or not with tumor necrosis factor (TNF) for 72 h to induce TRPA1 protein. CBG increased intracellular calcium levels in TNF-stimulated RASF but not unstimulated RASF in a TRPA1-dependent manner. In addition, PoPo3 uptake, a surrogate marker for drug uptake, was enhanced by CBG. RASF cell viability, IL-6 and IL-8 production were decreased by CBG. In peripheral blood mononuclear cell cultures (PBMC) alone or together with RASF, CBG-modulated interleukin (IL)-6, IL-10, TNF and immunoglobulin M and G production which was dependent on activation stimulus (T cell-dependent or independent). However, effects on PBMCs were only partially mediated by TRPA1 as the antagonist A967079 did inhibit some but not all effects of CBG on cytokine production. In contrast, TRPA1 antagonism even enhanced the inhibitory effects of CBG on immunoglobulin production. CBG showed broad anti-inflammatory effects in isolated RASF, PBMC and PBMC/RASF co-cultures. As CBG is non-psychotropic, it might be used as add-on therapy in RA to reduce IL-6 and autoantibody levels.

[Role of the sympathetic nervous system in chronic inflammation]. / Rolle des sympathischen Nervensystems bei chronischen Entzündungen.

In this review article the current model of the interaction between the sympathetic nervous system (SNS) and the immune system in the context of chronic inflammation is presented. Mechanisms in the interaction between the SNS and the immune system are shown, which are similar for all disease entities: 1) the biphasic effect of the sympathetic system on the inflammatory response with a proinflammatory, stimulating effect before and during the activation of the immune system (early) and a more inhibitory effect in late phases of immune activation (chronic). 2) The interruption of communication between immune cells and the brain by withdrawal of sympathetic nerve fibers from areas of inflammation, such as the spleen, lymph nodes or peripheral foci of inflammation. 3) The local replacement of catecholamines by neurotransmitter-producing cells to fine-tune the local immune response independently of the brain. 4) Increased activity of the SNS due to an imbalance of the autonomic nervous system at the systemic level, which provides an explanation for known disease sequelae and comorbidities due to the long duration of chronic inflammatory reactions, such as increased cardiovascular risk with hypertension, diabetes mellitus and catabolic metabolism. The understanding of neuroimmune interactions can lead to new therapeutic approaches, e.g., a stimulation of beta-adrenergic and even more an inhibition of alpha-adrenergic receptors or a restoration of the autonomic balance in the context of arthritis ) can make an anti-inflammatory contribution (more influence of the vagus nerve); however, in order to translate the theoretical findings into clinical action that is beneficial for the patient, controlled interventional studies are required.

[Energy metabolism of the immune system : Consequences in chronic inflammation]. / Energiemetabolismus des Immunsystems : Konsequenzen bei chronischen Entzündungen.

BACKGROUND: Energy is the currency of life. The systemic and intracellular energy metabolism plays an essential role for the energy supply of the resting and activated immune system and this also applies to chronic inflammatory diseases. OBJECTIVE: This presentation examines both components of the systemic and cellular energy metabolism in health and chronic inflammation. MATERIAL AND METHODS: A literature search was conducted using PubMed, Embase and the Cochrane Library. The information is presented in the form of a narrative review. RESULTS: A chronically activated immune system acquires large amounts of energy-rich substrates that are lost for other functions of the body. In particular, the immune system and the brain are in competition. The consequences of this competition are many known diseases, such as fatigue, anxiety, depression, anorexia, sleep problems, sarcopenia, osteoporosis, insulin resistance, hypertension and others. The permanent change in the brain causes long-term alterations that stimulate disease sequelae even after disease remission. In the intracellular energy supply, chronic inflammation typically involves a conversion to glycolysis (to lactate, which has its own regulatory functions) and the pentose phosphate pathway in disorders of mitochondrial function. The chronic changes in immune cells of patients with rheumatoid arthritis (RA) lead to a disruption of the citric acid cycle (Krebs cycle). The hypoxic situation in the inflamed tissue stimulates many alterations. A differentiation is made between effector functions and regulatory functions of immune cells. CONCLUSION: Based on the energy changes mentioned, novel treatment suggestions can be made in addition to those already known in energy metabolism.

[S1 Guideline Post-COVID/Long-COVID]. / S1-Leitlinie Post-COVID/Long-COVID.

The German Society of Pneumology initiated the AWMFS1 guideline Post-COVID/Long-COVID. In a broad interdisciplinary approach, this S1 guideline was designed based on the current state of knowledge.The clinical recommendation describes current post-COVID/long-COVID symptoms, diagnostic approaches, and therapies.In addition to the general and consensus introduction, a subject-specific approach was taken to summarize the current state of knowledge.The guideline has an expilcit practical claim and will be continuously developed and adapted by the author team based on the current increase in knowledge.

Association between autoantibody level and disease activity in rheumatoid arthritis is dependent on baseline inflammation.

OBJECTIVES: It is still controversial whether autoantibody (AAb) serum levels have a value for response monitoring in rheumatoid arthritis (RA). Therefore, we retrospectively investigated a real-life outpatient RA cohort to determine which factors are associated with change in serum AAb levels and RA disease activity. The primary goal of the study was to determine predictors for changes in DAS28 and autoantibodies over time and identify traits of non-rituximab treated patients, which would define strong association of disease activity with changes in AAb-levels. METHODS: Seventy-eight patients with seropositive RA were monitored for DAS28, CRP, ESR, anti-cyclic citrullinated peptides (CCP), anti-mutated citrullinated vimentin (MCV), and rheumatoid factor (RF). Using linear mixed regression modelling, factors influencing DAS28 and serum AAb were determined. Patients showing above (good correlators) and below (bad correlators) average correlation of serum AAb with DAS28 were further characterised. RESULTS: In non-rituximab treated patients (88.5%), associations of changes in AAb and DAS28 were strengthened with more morning stiffness (p=0.002), DMARD use (p=0.02), tender joints (p=0.01), swollen joints (p<0.01), higher ESR (p<0.01) and VAS (p<0.001) at baseline. Decrease of anti-CCP was also predicted by longer disease duration (-4.4 U/ml per year disease duration, p=0.048) and/or no erosions (-2.0 U/ml/month, p<0.01) at baseline, whereas erosive disease predicted an increase (+1.4 U/ml/month, p=0.015) in anti-CCP. Conversely, patients with erosive disease showed a trend to decrease RF (-1.9 U/ml/month, p=0.06). CONCLUSIONS: In non-rituximab treated RA patients, the association between disease activity and change in autoantibody levels is not static, but strengthens with increase in signs of inflammation (ESR, VAS, swollen joints, tender joints, morning stiffness) at baseline. Therefore, studies of changes in AAb need to consider baseline inflammation as confounder.

Joints for joints: cannabinoids in the treatment of rheumatoid arthritis.

PURPOSE OF REVIEW: An increasing number of patients with rheumatoid arthritis (RA) are using cannabis to treat their symptoms, although systematic studies regarding efficacy in RA are lacking. Within this review we will give an overview on the overall effects of cannabinoids in inflammation and why they might be useful in the treatment of RA. RECENT FINDINGS: Peripherally, cannabinoids show anti-inflammatory effects by activating cannabinoid type 2 receptors (CB2) which decrease cytokine production and immune cell mobilization. In contrast, cannabinoid type 1 receptor (CB1) activation on immune cells is proinflammatory while CB1 antagonism provides anti-inflammatory effects by increasing ß2-adrenergic signaling in the joint and secondary lymphoid organs. In addition, the nonpsychotropic cannabinoid, cannabidiol (CBD) demonstrated antiarthritic effects independent of cannabinoid receptors. In addition to controlling inflammation, cannabinoids reduce pain by activating central and peripheral CB1, peripheral CB2 receptors and CBD-sensitive noncannabinoid receptor targets. SUMMARY: Cannabinoids might be a suitable treatment for RA, but it is important to target the right receptors in the right place. For clinical studies, we propose a combination of a CB2 agonist to decrease cytokine production, a peripheral CB1 antagonist to prevent detrimental CB1 signaling and to support anti-inflammatory effects of CB2 via activation of ß2-adrenergic receptors and CBD to induce cannabinoid-receptor-independent anti-inflammatory effects.

Tryptophan metabolism in rheumatoid arthritis is associated with rheumatoid factor and predicts joint pathology evaluated by the Rheumatoid Arthritis MRI Score (RAMRIS).

OBJECTIVES: Tryptophan and its metabolites have been suggested to play a role in inflammatory processes. However, studies in rheumatoid arthritis (RA) are scarce, which prompted us to investigate two cohorts of RA patients to better understand the importance of tryptophan metabolism in this disease. METHODS: Tryptophan and its metabolites were characterised by ELISA in a cross-sectional cohort 1 (81 RA, 55 OA) and a longitudinal cohort 2 (25 RA, 3 visits over 6 months) to investigate discriminatory power between diseases and predicitive value for radiologic outcome, respectively. Radiologic outcome was monitored by RA MRI Score (RAMRIS), including grading of synovitis, bone oedema and erosion, as well as delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) index assessing cartilage quality of the MCP II joint. RESULTS: RA patients showed higher levels of serum serotonin (RA: 206.8 ng/ml ± 156.7; OA: 81.2 ng/ml ± 63.6) and estimated indoleamine (2,3)-dioxygenase (IDO) activity (kynurenine / tryptophan ratio; RA: 0.065±0.067; OA: 0.021±0.010). IDO activity showed similar, or better discriminatory power between RA and OA (AUC 0.914) than anti-CCP antibody level (AUC 0.922) and rheumatoid factor (RF, AUC 0.783), respectively. In cohort 2, regression analysis revealed a predictive value of baseline serotonin levels and IDO activity for changes in RAMRIS score and erosions at month six, respectively. CONCLUSIONS: This study supports the hypothesis that tryptophan and its metabolites can be used as biomarkers predicting radiologic outcome and discriminate between RA and OA patients. Overall, our results strengthen the notion that tryptophan metabolism is closely linked to RA disease mechanisms.

Identification of antibodies against extracellular matrix proteins in human osteoarthritis.

We investigated the presence of autoantibodies against the extracellular matrix proteins thrombospondin-4 (TSP-4), cartilage oligomeric matrix protein (COMP), C-type lectin domain family 3 member A (CLEC3A), collagen II, collagen VI, matrilin-3, and fibrillin-2 in the serum of osteoarthritis (OA) patients. We compared those results with the presence of such antibodies in rheumatoid arthritis (RA) patients and in healthy donors (HD). Our study examines whether antibodies against extracellular proteins can be used as potential biomarkers to support the clinical diagnosis of OA. 10 OA, 10 RA patients and 10 HD were enrolled in this explorative cross-sectional study. SDS-PAGE and immunoblot were used to investigate the presence of antibodies against extracellular matrix proteins. The serum of 5/10 OA patients but 0/10 HD exhibited TSP-4 IgG isotype antibodies (P = 0.033). The serum of 8/10 OA patients but only 1/10 HD exhibited IgG isotype antibodies against TSP-4 or COMP (P = 0.005). The serum of 9/10 OA patients but only 1/10 HD exhibited IgG isotype antibodies against TSP-4, COMP or CLEC3A (P = 0.005). We found strong evidence for the presence of IgG isotype autoantibodies against the cartilage extracellular matrix proteins TSP-4, COMP and CLEC3A in OA. The detection of IgG isotype autoantibodies against TSP-4, COMP and CLEC3A may support the clinical diagnosis of OA. OA with autoantibodies against cartilage extracellular matrix proteins defines a new OA subgroup suggesting that patients with high concentrations of autoantibodies may benefit from an immune suppressive therapy.

The ability of rheumatologists blinded to prior workup to diagnose rheumatoid arthritis only by clinical assessment: a cross-sectional study.

Objectives: We aimed to study the ability of board-certified rheumatologists, blinded to all prior diagnostic test results, to establish the presence/absence of an inflammatory rheumatic disease (IRD) or RA among polyarthralgia or arthritis patients, solely relying on clinical assessment. Methods: We performed a prospective, examiner-blinded, cross-sectional study documenting the diagnostic work in four sequential steps (medical history, physical examination, musculoskeletal ultrasonography and laboratory tests) of board-certified rheumatologists in a convenience cohort of 100 patients referred for inpatient diagnostic workup to a tertiary care rheumatology centre. Results: The ability to correctly identify patients with or without an IRD (diagnostic accuracy) increased from 27% after the clinical assessment to 53% after the ultrasonography and to 70% after taking laboratory test results into account. The corresponding values for correctly identifying patients with or without RA were 19, 42 and 60%, respectively. Therefore the diagnostic accuracy of solely clinical assessment for determining the diagnosis of IRD or RA compared with the diagnosis established by a consecutive thorough in-patient workup was only 27 and 19% in our cohort, respectively. Pretreatment with corticosteroids (in the prior 7 days) vs none did not alter these results substantially (20 vs 29% for IRD, 15% vs 20% for RA). Conclusion: Experienced rheumatologists, if deprived of information on prior external imaging and laboratory workup by blinding, were not able to correctly classify the majority of patients presenting with polyarthralgia or arthritis symptoms for inpatient workup, relying only on a brief symptom-focused medical history and physical examination.

Peripheral elimination of the sympathetic nervous system stimulates immunocyte retention in lymph nodes and ameliorates collagen type II arthritis.

OBJECTIVES: In collagen type II-induced arthritis (CIA), early activation of the sympathetic nervous system (SNS) is proinflammatory. Here, we wanted to find new target organs contributing to proinflammatory SNS effects. In addition, we wanted to clarify the importance of SNS-modulated immunocyte migration. METHODS: A new technique termed spatial energy expenditure configuration (SEEC) was developed to demonstrate bodily areas of high energy demand (to find new targets). We studied homing of labeled cells in vivo, lymphocyte expression of CCR7, supernatant concentration of CCL21, and serum levels of sphingosine-1-phosphate (S1P) in sympathectomized control/arthritic animals. RESULTS: During the course of arthritis, SEEC identified an early marked increase of energy expenditure in draining lymph nodes and spleen (nowhere else!). Although early sympathectomy ameliorated later disease, early sympathectomy increased energy consumption, organ weight, and cell numbers in arthritic secondary lymphoid organs, possibly a sign of lymphocyte retention (also in controls). Elimination of the SNS retained lymph node cells, elevated expression of CCR7 on lymph node cells, and increased CCL21. Serum levels of S1P, an important factor for lymphocyte egress, were higher in arthritic than control animals. Sympathectomy decreased S1P levels in arthritic animals to control levels. Transfer of retained immune cells from draining lymph nodes of sympathectomized donors to sympathectomized recipients markedly increased arthritis severity over weeks. CONCLUSIONS: By using the SEEC technique, we identified draining lymph nodes and spleen as major target organs of the SNS. The data show that the SNS increases egress of lymphocytes from draining lymph nodes to stimulate arthritic inflammation.

A sustained high fat diet for two years decreases IgM and IL-1 beta in ageing Wistar rats.

BACKGROUND: The immune system undergoes several alterations of innate and adaptive immunity during ageing. The main features of the aged immune system are a reduced diversity of T cell receptors and a reduced activity of innate immune cells with subsequent changes in adaptive immunity resulting in a less effective, less specific, and dys-regulated immune response and in an increased susceptibility towards infection, malignancy, and autoimmunity. The process is referred to as immunosenescence and is also modulated by environmental modifiers, such as dietary factors. High fat diet (HFD), via direct modulation of immune cell function by fatty acids and/or increased body fat mass, influences immune function. However, it is not clear whether HFD is beneficial or detrimental for the functioning of the ageing immune system. METHODS: Male Wistar rats fed with either a high fat diet (HFD 43 en% of fat) or control diet (SD, 25 en% of fat) over up to 24 month and were analyzed for plasma IL-1ß, IL-6, TNF, IgM, IgG1, IgA, IgG2a, IgG2b, IgG2c, light chains lambda and kappa, testosterone, prolactin and percentage of splenic B cells and apoptosis rate, respectively. RESULTS: In general, all analyzed immunoglobuline isotypes increased with age, except for IgA. This increase was attenuated by HFD. In HFD and SD rats the percentage of B cells in the spleen and also their apoptotic rate was lower in aged as compared to young animals with no additional diet-induced effect. Testosterone and prolactin levels were lower in old animals, as expected. There was a statistical trend towards an increased prolactin/testosterone ratio in middle aged (6-12 monthsnth) HFD rats as compared to SD. IL-6 was neither affected by HFD nor age. On the other hand, HFD rats showed a decrease in IL-1ß as compared to SD, which correlated with the above-mentioned suppressive effect on immunoglobulin isotypes, especially IgM. CONCLUSION: In Wistar rats, HFD reveals an immunosuppressive effect in ageing animals by decreasing immunoglobulins, especially IgM, and IL-1ß when compared to SD.

IL-7 receptor α expressing B cells act proinflammatory in collagen-induced arthritis and are inhibited by sympathetic neurotransmitters.

OBJECTIVES: The sympathetic nervous system (SNS) as well as the interleukin (IL)-7/IL-7 receptor (IL-7R) system play a role in the pathogenesis of arthritis. However, the target cells and mechanisms involved are not fully resolved. The goal of this study was to determine if B cells are influenced by IL-7 and to investigate the possible interplay between the SNS and the IL-7/IL-7R system on B cells in arthritis. METHODS: Collagen type II-induced arthritis (CIA) in DBA1 mice. ELISA to determine specific anti-CII antibodies. Fluorescence activated cell sorting (FACS) analysis to determine IL-7R+ cells and intracellular phosphorylated signal transducer and activator of transcription 5 (pSTAT5). Immunohistochemistry to show IL-7R+ B cells in rheumatoid arthritis (RA) and osteoarthritis (OA) synovial tissue. RESULTS: IL-7 stimulated IL-7R+ mature B cells act proinflammatory (increased clinical score, increased anticollagen type II antibodies) after cell transfer in CIA. The sympathetic neurotransmitter norepinephrine abrogates this effect. Expression of IL-7Rα is increased when B cells are activated (anti-CD40 or lipopolysaccharide) in vitro and stimulating the IL-7R induces intracellular accumulation of pSTAT5. α- And ß-adrenergic agonists show no influence on expression levels of IL-7R on activated B cells; however, intracellular IL-7R downstream signalling is abrogated via the ß2-adreonceptor (ß2AR) agonist terbutaline. IL-7R and ß2AR are also expressed on B cells in synovial tissue from RA and OA patients. CONCLUSIONS: These data indicate that IL7R+ B cells have a proinflammatory role in arthritis which can be inhibited by the sympathetic neurotransmitter norepinephrine via inhibition of IL-7R signalling.

Impact of filgotinib on pain control in the phase 3 FINCH studies.

OBJECTIVE: This post hoc analysis of the FINCH 1-3 (NCT02889796, NCT02873936 and NCT02886728) studies assessed specific effects of filgotinib on pain control and their relationship with other aspects of efficacy in patients with rheumatoid arthritis (RA). METHODS: Assessments included: residual pain responses of ≤10 and ≤20 mm on a 100 mm visual analogue scale (VAS); the proportion of patients who achieved VAS pain responses in addition to remission or low disease activity by Disease Activity Score-28 with C-reactive protein (DAS28-CRP) or Clinical Disease Activity Index (CDAI) criteria. RESULTS: Across studies, filgotinib reduced pain from week 2, with responses sustained throughout the studies. In FINCH 1, at week 24, 35.8%, 25.0%, 24.6% and 11.6% of patients in the filgotinib 200 mg, filgotinib 100 mg, adalimumab and placebo arms (each plus methotrexate) achieved VAS pain ≤20 mm in addition to DAS28-CRP remission; 26.3%, 17.9%, 17.2% and 7.6% achieved VAS pain ≤10 mm in addition to DAS28-CRP remission. A similar pattern was seen for CDAI remission. Time during which VAS pain was ≤10 or ≤20 mm was longest with filgotinib 200 mg and comparable between adalimumab and filgotinib 100 mg. Similar findings were reported for filgotinib in FINCH 2 and 3. CONCLUSION: In all RA populations studied, pain improvements occurred from week 2 and were sustained over time. In FINCH 1, filgotinib 100 mg provided similar pain amelioration to adalimumab, whereas filgotinib 200 mg resulted in greater pain improvement and higher proportion of patients with residual pain ≤10 or ≤20 mm and meeting DAS28-CRP remission criteria.

Neuronal α1/2-adrenergic stimulation of IFN-γ, IL-6, and CXCL-1 in murine spleen in late experimental arthritis.

OBJECTIVE: Functional cross-talk exists between sympathetic nerve fibers and cytokine-producing splenic cells in early collagen type II-induced arthritis (CIA) (day 32). These earlier experiments demonstrated exclusively neuronal sympathetic regulation of IFN-γ, CXCL1, IL-6, and TGF-ß. However, in late arthritis, the sympathetic influence might change due to loss of sympathetic nerve fibers and appearance of neurotransmitter-producing cells. We aimed to investigate neurotransmitter-dependent regulation of IFN-γ, CXCL1, IL-6, and TGF-ß in murine spleen in late CIA. METHODS: Spleens were removed when animals reached day 58 (46-68) after immunization to generate 0.35 mm-thick spleen slices, which were transferred to superfusion microchambers to electrically induce release of neurotransmitters. Using respective neurotransmitter antagonists, effects of released neurotransmitters on cytokine secretion were investigated. RESULTS: There was electrically induced inhibition of IFN-γ, CXCL1, and IL-6, and stimulation of TGF-ß, which was much less pronounced than in early CIA. There existed ß adrenergic inhibition of IFN-γ, IL-6, and TGF-ß (and stimulation of CXCL1) independent of electrical stimulation (interpreted as non-neuronal). However, there was a neuronal α1/2 adrenergic stimulation of IFN-γ, CXCL1, and IL-6 and, we observed neuronal A1-adenosinergic stimulation of TGF-ß. CONCLUSIONS: In the late phase of CIA, non-neuronal modulation of cytokine secretion increases while neuronal regulation strikingly decreases. Particularly, ß-adrenergic effects are non-neuronal while α1/2-adrenergic effects are clearly neuronal. We suggest that alterations in sympathetic innervation of the spleen fundamentally change the functional neuroimmune interplay in the spleen of arthritic mice.

Components of the sympathetic nervous system as targets to modulate inflammation - rheumatoid arthritis synovial fibroblasts as neuron-like cells?

BACKGROUND: Catecholamines are major neurotransmitters of the sympathetic nervous system (SNS) and they are of pivotal importance in regulating numerous physiological and pathological processes. Rheumatoid arthritis (RA) is influenced by the activity of the SNS and its neurotransmitters norepinephrine (NE) and dopamine (DA) and early sympathectomy alleviates experimental arthritis in mice. In contrast, late sympathectomy aggravates RA, since this procedure eliminates anti-inflammatory, tyrosine hydroxylase (TH) positive cells that appear in the course of RA. While it has been shown that B cells can take up, degrade and synthesize catecholamines it is still unclear whether this also applies to synovial fibroblasts, a mesenchymal cell that is actively engaged in propagating inflammation and cartilage destruction in RA. Therefore, this study aims to present a detailed description of the catecholamine pathway and its influence on human RA synovial fibroblasts (RASFs). RESULTS: RASFs express all catecholamine-related targets including the synthesizing enzymes TH, DOPA decarboxylase, dopamine beta-hydroxylase, and phenylethanolamine N-methyltransferase. Furthermore, vesicular monoamine transporters 1/2 (VMAT1/2), dopamine transporter (DAT) and norepinephrine transporter (NET) were detected. RASFs are also able to degrade catecholamines as they express monoaminoxidase A and B (MAO-A/MAO-B) and catechol-O-methyltransferase (COMT). TNF upregulated VMAT2, MAO-B and NET levels in RASFs. DA, NE and epinephrine (EPI) were produced by RASFs and extracellular levels were augmented by either MAO, COMT, VMAT or DAT/NET inhibition but also by tumor necrosis factor (TNF) stimulation. While exogenous DA decreased interleukin-6 (IL-6) production and cell viability at the highest concentration (100 µM), NE above 1 µM increased IL-6 levels with a concomitant decrease in cell viability. MAO-A and MAO-B inhibition had differential effects on unstimulated and TNF treated RASFs. The MAO-A inhibitor clorgyline fostered IL-6 production in unstimulated but not TNF stimulated RASFs (10 nM-1 µM) while reducing IL-6 at 100 µM with a dose-dependent decrease in cell viability in both groups. The MAO-B inhibitor lazabemide hydrochloride did only modestly decrease cell viability at 100 µM while enhancing IL-6 production in unstimulated RASFs and decreasing IL-6 in TNF stimulated cells. CONCLUSIONS: RASFs possess a complete and functional catecholamine machinery whose function is altered under inflammatory conditions. Results from this study shed further light on the involvement of sympathetic neurotransmitters in RA pathology and might open therapeutic avenues to counteract inflammation with the MAO enzymes being key candidates.