Sensing the main health concerns in patients with established rheumatoid arthritis

CdSe magic-sized quantum dots attenuate reactive oxygen species generated by neutrophils and macrophages with implications in experimental arthritis

The biological applicability of nanomaterials has been limited due to cytotoxicity. Studies have described the effects of nanomaterials on different tissues and cell types, but their actions on immune cells are less elucidated. This study describes unprecedented in vitro and in vivo antioxidant activities of cadmium selenide magic-sized quantum dots (CdSe MSQDs) with implications on rheumatoid arthritis. While the generation of ROS induced by nanomaterials is linked to cytotoxicity, we found that CdSe MSQDs reduced ROS production by neutrophils and macrophages following opsonized-zymosan stimuli, and we did not find cytotoxic effects. Interestingly, inherent antioxidant properties of CdSe MSQDs were confirmed through DPPH, FRAP, and ORAC assays. Furthermore, CdSe MSQDs reduced ROS levels generated by infiltrating leukocytes into joints in experimental model of rheumatoid arthritis. Briefly, we describe a novel application of CdSe MSQDs in modulating the inflammatory response in experimental rheumatoid arthritis through an unexpected antioxidant activity.

Chronic Pain in Patients with Rheumatoid Arthritis

PURPOSE OF REVIEW

Chronic pain is highly prevalent in patients with rheumatoid arthritis (RA) and can cause various physical and psychological impairments. Unfortunately, the appropriate diagnosis of chronic pain syndromes in this population can be challenging because pain may be primary to RA-specific inflammation and/or secondary to other conditions, typically osteoarthritis (OA) and fibromyalgia (FM). This disparity further poses a clinical challenge, given that chronic pain can often be discordant or undetected with standard RA-specific surveillance strategies, including serological markers and imaging studies. In this review, we provide a robust exploration of chronic pain in the RA population with emphasis on epidemiology, mechanisms, and management strategies.

RECENT FINDINGS

Chronic pain associated with RA typically occurs in patients with anxiety, female sex, and elevated inflammatory status. Up to 50% of these patients are thought to have chronic pain despite appropriate inflammatory suppression, typically due to peripheral and central sensitization as well as secondary OA and FM. In addition to the standard-of-care management for OA and FM, patients with RA and chronic pain benefit from behavioral and psychological treatment options. Moreover, early and multimodal therapies, including non-pharmacological, pharmacological, interventional, and surgical strategies, exist, albeit with varying efficacy, to help suppress inflammation, provide necessary analgesia, and optimize functional outcomes. Overall, chronic pain in RA is a difficult entity for both patients and providers. Early diagnosis, improved understanding of its mechanisms, and initiation of early, targeted approaches to pain control may help to improve outcomes in this population.

Increased Serum Interleukin-2 Levels Are Associated with Abnormal Peripheral Blood Natural Killer Cell Levels in Patients with Active Rheumatoid Arthritis

Objective

To investigate the relationship between serum interleukin-2 (IL-2) levels and disease activity, absolute numbers of peripheral lymphocyte subsets, autoantibodies, and associated cytokines in patients with rheumatoid arthritis (RA).

Methods

This study included 106 patients with RA, evaluated their disease activity (DAS28 score), and divided them into disease remission (DAS28 ≤ 2.6), low disease activity (DAS28 ≤ 3.2), and moderate-high disease activity (DAS28 > 3.2) groups. Flow cytometry was used to detect the absolute numbers of peripheral lymphocyte subpopulations and CD4+ T cell subsets in each group, and serum cytokine levels were measured using cytometric bead array.

Results

Serum IL-2 levels in RA patients were positively correlated with disease activity and rheumatoid factor titers (p < 0.001 and p = 0.045, respectively), and multiple regression analysis revealed that serum IL-2 levels were an independent factor affecting disease activity. Serum IL-2 levels were positively correlated with Th17/Treg ratios (p = 0.013). Compared with the remission group, peripheral lymphocyte and CD4+ T lymphocyte subsets in patients with active RA decreased to varying degrees; however, the numbers of peripheral natural killer (NK) cells were significantly higher in the moderate-high disease activity group than in the remission (p = 0.046) and low disease activity (p = 0.020) groups; the percentages of NK cells had the same trend. In addition, the number and percentage of NK cells were positively correlated with serum IL-2 levels (p = 0.018 and p = 0.006, respectively).

Conclusions

In RA patients, serum IL-2 levels were not only correlated with patients' disease activity and autoantibody levels but were also involved in their Th17/Treg immune imbalance. In addition, in patients with active RA, NK cell levels were abnormally elevated, possibly due to high serum levels of IL-2.

Association of Pain Centralization and Patient-Reported Pain in Active Rheumatoid Arthritis

OBJECTIVE

Pain is a significant burden for patients with rheumatoid arthritis (RA) despite advancements in treatment. We undertook this study to examine the independent contribution of pain centralization to the pain experience of patients with active RA.

METHODS

A total of 263 RA patients with active disease underwent quantitative sensory testing (QST), including assessment of extraarticular pressure pain thresholds (PPTs), temporal summation (TS), and conditioned pain modulation (CPM). The pain experience was assessed by a pain intensity numeric rating scale and the Patient-Reported Outcomes Measurement Information System pain interference computerized adaptive test. We examined associations between QST measures and pain intensity and pain interference. Multiple linear regression models were adjusted for demographic and clinical variables, including swollen joint count and C-reactive protein level.

RESULTS

Patients with the lowest PPTs (most central dysregulation) reported higher pain intensity than patients with the highest PPTs (adjusted mean difference 1.02 [95% confidence interval (95% CI) 0.37, 1.67]). Patients with the highest TS (most central dysregulation) had higher pain intensity than those with the lowest TS (adjusted mean difference 1.19 [95% CI 0.54, 1.84]). CPM was not associated with differences in pain intensity. PPT and TS were not associated with pain interference. Patients with the lowest CPM (most centrally dysregulated) had lower pain interference than patients with the highest CPM (adjusted mean difference -2.35 [95% CI -4.25, -0.44]).

CONCLUSION

Pain centralization, manifested by low PPTs and high TS, was associated with more intense pain. Clinicians should consider pain centralization as a contributor to pain intensity, independent of inflammation.

Mechanisms for Joint Pain in Rheumatoid Arthritis (RA): from Cytokines to Central Sensitization

PURPOSE OF REVIEW

Pain in rheumatoid arthritis (RA) may be due to different etiologies, ranging from peripheral inflammation to dysregulation of central nervous system (CNS) processing. This review evaluates relevant literature published on RA pain mechanisms in recent years.

RECENT FINDINGS

Despite successes of disease-modifying antirheumatic drugs (DMARDs), pain persists for many RA patients. Studies involving patient-reported outcomes, quantitative sensory testing, and neuroimaging indicate that, in addition to joint inflammation, abnormalities in CNS pain processing may contribute to pain. Some DMARDs (e.g., janus kinus inhibitors) may work via multiple pathways to decrease pain. Adjunctive treatments (e.g., antidepressants, antiepileptics) may also be useful in managing pain in RA patients with well-controlled disease. Both peripheral and central mechanisms play key roles in the expression of pain in RA. To effectively manage pain, physicians need accurate assessment tools to identify the pathways involved in each patient so that treatments may be appropriately targeted.