Electroacupuncture Alleviates Pain by Suppressing P2Y12R-Dependent Microglial Activation in Monoarthritic Rats

Electroacupuncture (EA) effectively improves arthritis-induced hyperalgesia and allodynia by repressing spinal microglial activation, which plays a crucial role in pain hypersensitivity following tissue inflammation. However, the mechanism by which EA suppresses spinal microglial activation in monoarthritis (MA) remains unclear. In the present study, a rat model of MA was established through unilateral ankle intra-articular injection of complete Freund's adjuvant (CFA). The relationship among P2Y12 receptor (P2Y12R) expression, spinal microglial activation, and EA analgesia was investigated using quantitative real-time PCR (qRT‒PCR), western blotting, immunofluorescence (IF), and behavioral testing. The results found that EA treatment at the ipsilateral "Huantiao" (GB30) and "Yanglingquan" (GB34) acupoints markedly attenuated pain and spinal microglia M1 polarization in MA rats. In particular, P2Y12R expression was significantly increased at the mRNA and protein levels in the spinal dorsal horn in MA rats, whereas EA treatment effectively repressed the MA-induced upregulation of P2Y12R. IF analysis further revealed that most P2Y12R was expressed in microglia in the spinal dorsal horn. Pharmacological inhibition of P2Y12R by its antagonist (AR-C69931MX) decreased MA-induced spinal microglial activation and subsequent proinflammatory cytokine production. Consequently, AR-C69931MX significantly intensified the anti-pain hypersensitive function of EA in MA rats. Taken together, these results demonstrate that EA alleviates MA-induced pain by suppressing P2Y12R-dependent microglial activation.

Translational evaluation of gait behavior in rodent models of arthritic disorders with the CatWalk device - a narrative review

Arthritic disorders have become one of the main contributors to the global burden of disease. Today, they are one of the leading causes of chronic pain and disability worldwide. Current therapies are incapable of treating pain sufficiently and preventing disease progression. The lack of understanding basic mechanisms underlying the initiation, maintenance and progression of arthritic disorders and related symptoms represent the major obstacle in the search for adequate treatments. For a long time, histological evaluation of joint pathology was the predominant outcome parameter in preclinical arthritis models. Nevertheless, quantification of pain and functional limitations analogs to arthritis related symptoms in humans is essential to enable bench to bedside translation and to evaluate the effectiveness of new treatment strategies. As the experience of pain and functional deficits are often associated with altered gait behavior, in the last decades, automated gait analysis has become a well-established tool for the quantitative evaluation of the sequalae of arthritic disorders in animal models. The purpose of this review is to provide a detailed overview on the current literature on the use of the CatWalk gait analysis system in rodent models of arthritic disorders, e.g., Osteoarthritis, Monoarthritis and Rheumatoid Arthritis. Special focus is put on the assessment and monitoring of pain-related behavior during the course of the disease. The capability of evaluating the effect of distinct treatment strategies and the future potential for the application of the CatWalk in rodent models of arthritic disorders is also addressed in this review. Finally, we discuss important consideration and provide recommendations on the use of the CatWalk in preclinical models of arthritic diseases.

Delayed diagnosis of pediatric intra-articular epithelioid sarcoma: a case report and literature review

BACKGROUND

Epithelioid sarcoma (ES) is a rare form of mesenchymal malignancy that rarely occurs in children. Only seven cases of intra-articular epithelioid sarcoma have been reported in the medical literature.

CASE PRESENTATION

In this report, we presented the case of a 13-year-old girl with a delayed diagnosis of ES in the left knee. Her initial diagnosis was mistaken for Pigmented Villonodular Synovitis (PVNS) but ruled out later by the first biopsy. However, the lesion rapidly regrew again after arthroscopy, raising suspicions of malignancy. A comprehensive histochemistry examination was conducted again, leading to the diagnosis of INI-1 negative epithelioid sarcoma. Unfortunately, the girl passed away seven months later due to early metastasis of the tumor.

CONCLUSION

Careful consideration should be given to the differential diagnosis of pediatric patients presenting with monoarthritis. This report highlights the importance of early and accurate diagnosis and underscores the necessity for effective treatments for epithelioid sarcoma. Surgical resection or radical surgery is recommended, while novel treatment strategies targeting EZH2 show promise.

Intra-articular therapy with methotrexate or tumor necrosis factor inhibitors in rheumatoid arthritis: a systematic review

Background

Persistent monoarthritis in otherwise well-controlled rheumatoid arthritis presents a therapeutic challenge. Intra-articular (IA) steroids are a mainstay of treatment, though some have queried whether IA disease modifying anti-rheumatic drugs (DMARD) and biologics can be used in those who fail steroid injections.

Methods

A systematic literature review was conducted using four medical databases to identify randomized, controlled trials assessing IA therapies in RA patients. Included studies underwent Cochrane Risk of Bias 2 assessment for quality.

Results

Twelve studies were included, 6 of which examined intra-articular (IA) TNF inhibitors (TNFi), and 6 studies evaluating IA methotrexate. Of those evaluating IA TNFi, one study reported statistical improvement in TNFi therapy when compared with placebo. The remaining 5 studies compared IA TNFi therapy with steroid injections. IA TNFi had statistically improved symptom scores and clinical assessments comparable with IA steroid treatments.

In the 6 studies evaluating IA methotrexate, the addition of methotrexate to steroid intra-articular therapy was not found to be beneficial, and singular methotrexate injection was not superior to the control arms (saline or triamcinolone). Risk-of-bias (ROB) assessment with the Revised Cochrane ROB tool indicated that 2 of 6 TNFi studies were at some risk or high risk for bias, compared with 5 out of 6 methotrexate studies.

Conclusion

For persistent monoarthritis in rheumatoid arthritis, IA methotrexate was not found to have clinical utility. Intra-articular TNFi therapy appears to have equal efficacy to IA steroids, though the optimal dose and frequency of injections is yet unknown.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04651-5.

[Post-Corona-Virus-Disease‑19 arthritis. Manifestation under the clinical picture of a reactive arthritis]

A total of 13 case reports of reactive arthritis reported in the literature in connection with coronavirus disease 2019 (COVID‑19) are reviewed. Men were affected more frequently than women. The arthritis was manifested 4-44 days after the infection or the occurrence of the COVID‑19 symptoms. Acute arthritis was monoarticular or oligoarticular. Only 1 out of 7 patients examined was human-leucocyte-antigen(HLA)-B27 positive. A direct viral infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) could not be detected in the synovial fluid and was not investigated in the synovial membrane. The arthritis was successfully treated with nonsteroidal anti-inflammatory drugs and/or intra-articular or systemic corticosteroids. The pathogenesis of post-COVID‑19 reactive arthritis is unknown.

Approach to a patient with monoarticular disease

PURPOSE

To reassess the diagnostic approach to a patient with a monoarticular disease in light of the up-to-date medical literature and to examine the practical utility of traditional and newer imaging tools in the setting of monoarthritis.

RESULTS

The monoarticular disease can represent a medical emergency on the one hand and be a diagnostic conundrum on the other. The management rules of patients with monoarthritis have been established long ago, but various pitfalls still lead physicians off the right diagnosis at times. Septic, pseudoseptic arthritis and hemarthrosis are the most common diagnoses made in patients with an acute presentation, and a decision not to perform a diagnostic arthrocentesis is the most prevalent cause of misdiagnosis in this setting. Many rheumatic and infectious diseases can present with more indolent monoarthritis; careful history and physical examination frequently provide clues to the straightforward diagnosis in some cases, but the extensive investigation is needed in others. Imaging methods become indispensable in individuals with the non-inflammatory monoarticular disease, with magnetic resonance imaging being the gold standard for diagnosing pigmented villonodular synovitis, lipoma arborescence, avascular necrosis, or neuropathic arthropathy.

CONCLUSIONS

A great variety of medical disorders can present as a monoarticular disease. The disease presentation dictates different diagnostic behavior, while knowing the available imaging methods' diagnostic potential should further shorten the diagnostic process.

[Recurrence of septic arthritis of the wrist by Pseudomonas aeruginosa due to colonization of a central venous indwelling catheter]

A diabetic patient, wearer of a port and with a history of gonarthritis due to Pseudomonas aeruginosa presented with subacute arthritis of a wrist. After a protracted interval P. aeruginosa was detected by microbial culture from the explanted port and the affected joint. This case shows that in patients with unclear arthritis of the wrist, a history of septic arthritis with P. aeruginosa and risk factors for hematogenous spread, a recurrent infection should be excluded. The treatment consisted of explantation of the port, débridement with synovectomy of the joint and adequate antibiotic treatment.

Pain-related behavior is associated with increased joint innervation, ipsilateral dorsal horn gliosis, and dorsal root ganglia activating transcription factor 3 expression in a rat ankle joint model of osteoarthritis

Supplemental Digital Content is Available in the Text.

In a rat model of osteoarthritis, we found increased joint sensory and sympathetic innervation and glia changes in dorsal horn, accompanying pain-related behavior onset.

Introduction:

Osteoarthritis (OA)-associated pain is often poorly managed, as our understanding of the underlying pain mechanisms remains limited. The known variability from patient to patient in pain control could be a consequence of a neuropathic component in OA.

Methods:

We used a rat monoiodoacetate model of the ankle joint to study the time-course of the development of pain-related behavior and pathological changes in the joint, dorsal root ganglia (DRG), and spinal cord, and to investigate drug treatments effects.

Results:

Mechanical hypersensitivity and loss of mobility (as assessed by treadmill) were detected from 4 weeks after monoiodoacetate. Cold allodynia was detected from 5 weeks. Using histology and x-ray microtomography, we confirmed significant cartilage and bone degeneration at 5 and 10 weeks. We detected increased nociceptive peptidergic and sympathetic fiber innervation in the subchondral bone and synovium at 5 and 10 weeks. Sympathetic blockade at 5 weeks reduced pain-related behavior. At 5 weeks, we observed, ipsilaterally only, DRG neurons expressing anti-activating transcription factor 3, a neuronal stress marker. In the spinal cord, there was microgliosis at 5 and 10 weeks, and astrocytosis at 10 weeks only. Inhibition of glia at 5 weeks with minocycline and fluorocitrate alleviated mechanical allodynia.

Conclusion:

Besides a detailed time-course of pathology in this OA model, we show evidence of contributions of the sympathetic nervous system and dorsal horn glia to pain mechanisms. In addition, late activating transcription factor 3 expression in the DRG that coincides with these changes provides evidence in support of a neuropathic component in OA pain.

[Multiple erythema annulare centrifugum associated with knee monoarthritis revealing Capnocytophagacanimorsus infection]

INTRODUCTION

Capnocytophagacanimorsus (C. canimorsus), a commensal Gram-negative bacillus found in the oral cavity of dogs and cats, is pathogenic for humans, with the most common clinical manifestations being septicemia, meningitis and endocarditis. Herein we report a case of CC bacteremia manifesting as multiple plaques of erythema annulare centrifugum associated with monoarthritis of the knee.

PATIENTS AND METHODS

A 66-year-old man consulted for a skin rash and monoarthritis of the right knee with fever following an insect bite on his right hallux. Cutaneous examination revealed numerous erythematous annular plaques on the trunk and limbs with centrifugal extension. Analysis of synovial fluid from the right knee showed an inflammatory liquid with a sterile bacteriological culture and PCR was negative for Borrelia. C. canimorsus bacteria were isolated from blood cultures. 16S RNA PCR performed on the synovial fluid was positive for the same organism. The patient's history revealed that his hallux wound had been licked by his dog.

DISCUSSION

C. canimorsus most frequently affects immunosuppressed subjects. Cutaneous signs are seen in half of all cases, most frequently presenting as cellulitis, pathological livedo or thrombotic purpura. We report herein a case of CC bacteremia in an immunocompetent patient manifesting as multiple plaques of erythema annulare centrifugum, an unusual sign, and monoarthritis of one knee.

Case series: Monoarticular rheumatoid arthritis

Objective

Monoarticular presentation of rheumatoid arthritis is infrequent and has been previously reported to involve large joints such as the hip and knee joints. Here we report a case series of four patients presenting to the University of Michigan in 2015 with monoarticular rheumatoid arthritis, one with small and three with large joint involvement.

Material and Methods

In total, four patients with monoarticular rheumatoid arthritis were treated in the Division of Rheumatology, University of Michigan. All the patients were retrospectively reviewed with permission from our Institutional Review Board; informed consent was provided by the patients for enrollment in a clinical trial for patients with rheumatoid arthritis. All the patients were assessed using the 2010 ACR/EULAR classification criteria for rheumatoid arthritis.

Results

All the patients presented with monoarthritis; three patients had large joint involvement and one had small joint involvement. Serologies were positive, with each patient having positive Anti-cyclic citrullinated peptide (anti-CCP) antibodies, two patients having a positive rheumatoid factor, three patients having elevated CRP levels, and one patient having positive ESR. All patients met the criteria of the duration of symptoms being at least 6 weeks. The findings of imaging, although not a part of the criteria, were consistent with active rheumatoid arthritis in all the patients.

Conclusion

While the 2010 ACR/EULAR classification criteria are the most sensitive criteria for diagnosing RA to date, the exclusion of these cases of monoarthritis demonstrates that further specificity can still be achieved for diagnosing these types of patients as early as possible using the current guidelines. Further, we suggest the inclusion of an imaging measure added to the inclusion criteria to further increase the yield in establishing diagnosis of rheumatoid arthritis in the current reported patient population.

Heterocyclic homoprostanoid derivative attenuates monoarthritis in rats: An in vitro and in vivo preclinical paradigm

From our lab, among the nineteen heterocyclic homoprostanoids (HHPs), three derivatives (compounds 3, 3b and 3c) exerted antioxidant and anti-inflammatory activity. Present study is an extension of the earlier work, and, is designed to establish their therapeutic potential in monoarthritis in rats. In addition, their possible mechanism of action would be investigated. A battery of in vitro tests such as lipopolysaccharide (LPS)-induced nitrite (NO)/reactive oxygen species (ROS) and NO/interleukin (IL)-6 generation in murine macrophages and whole blood (WhB), respectively were conducted. Later, in vitro cyclooxygenase (COX) enzyme inhibitory activity was also evaluated. All the tested compounds showed comparable efficacy against ROS and NO in LPS-stimulated murine macrophages. However, compound 3 did not exert inhibitory effect on LPS-induced NO/IL-6 generation in WhB assay. Compounds (3b and 3c) inhibited the NO generation in LPS-stimulated WhB. However, only compound 3b reversed the raised IL-6 levels in this assay. None of the test compounds inhibited COX iso-enzymes in the in vitro assay. All three HHPs showed comparable efficacy against carrageenan-induced paw inflammation. However, none of them exhibited any dose-dependent effect in this model. Based upon previous reports, compound 3c was explored against adjuvant-induced monoarthritis (AIA) in male Sprague-Dawley rats, where it exerted promising therapeutic effect. In addition to radiological and histological examinations of tibio-tarsal joint, various parameters such as chronic inflammation/pain, clinical score, interleukin (IL)-6 levels and complete blood cell profile were evaluated in AIA rats. Chronic treatment with 3c halted the disease progression in rats, improved the overall health of animals, as demonstrated by haematological, clinical scoring and joint examinations (radiological and histopathological). Inhibitory effect on elevated IL-6 in AIA rats suggested the possible mechanism of 3c on cytokine signalling. Overall, the study supports the anti-arthritic potential of compound 3c.

Inhibition of HCN channel activity in the thalamus attenuates chronic pain in rats

Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels regulate neuronal excitability in both peripheral and central nerve systems. Emerging evidence indicates that HCN channels are involved in the development and maintenance of chronic pain. However, the impact of HCN channel activity in the thalamus on chronic pain has not been examined. In this report, we evaluated the effect on nociceptive behaviors after infusion of a HCN channel blocker ZD7288 into the ventral posterolateral (VPL) nucleus of the thalamus in rats with neuropathic pain or monoarthritis. We show that ZD7288 dose-dependently attenuated mechanical allodynia and thermal hyperalgesia in rats with chronic pain. In the thalamus, immunoreactivity of both HCN1 and HCN2 subunits was increased in both rat models. These results suggest that the increased HCN channel activity in the thalamus of the ascending nociceptive pathway contributes to both chronic neuropathic and inflammatory pain conditions.

Managing monoarthritis in children

Monoarthritis, defined as inflammation of a single joint, requires a thorough physical examination in children, as pain may be lacking in 10% to 30% of cases and joint stiffness may be the only symptom. Joint aspiration is a crucial diagnostic tool that remains markedly underused. Joint aspiration may be unnecessary, however, when the family history or other investigations provide the diagnosis. Radiographs of the involved joint may supply information on the severity of the lesions. In doubtful cases and in patients with arthralgia, B-mode and Doppler ultrasound or magnetic resonance imaging (MRI) may confirm the presence of synovitis. Although suspected septic arthritis is an emergency and occurs frequently, particularly before 2 years of age, acute monoarthritis is often a post-infectious manifestation and therefore associated with a good outcome. Lyme disease should be sought, particularly when a lower limb joint is involved, as tick bites often go unnoticed. Chronic monoarthritis is very often a manifestation of juvenile idiopathic arthritis (JIA), which exists as several variants. Oligoarthritis is a specifically pediatric joint disease, whereas the other patterns of JIA have corresponding forms in adults, despite a number of specific features due to their onset during childhood. Tests for antinuclear antibodies should be performed routinely in children with monoarthritis persisting longer than 3 weeks. A decline in general health or a fever should suggest arthritis revealing a malignancy, which is a hematological disease in most cases. Finally, suggestive symptoms are often present in patients with less common causes such as auto-inflammatory diseases and connective tissue diseases.

[Lipoma arborescens of the knee in a patient with ankylosing spondylitis: case report and literature review]

Lipoma arborescens (LA) is defined as a villous lipomatous proliferation of the synovial membrane with diffuse substitution of the synovial tissue by mature fat cells. The injury is very rare, involving the knee joint (suprapatellar region) and is associated with degenerative joint disease. We describe the case of a male patient, suffering from ankylosing spondylitis with monoarthritis of the right knee and swelling in suprapatellar region important. The diagnosis of lipoma arborescens was confirmed from the MRI of the right knee.

Antinociceptive and anti-arthritic effects of kramecyne

AIMS

The aim of this study was to evaluate the antinociceptive (acute assays) and anti-inflammatory (chronic assays) effects of kramecyne (KACY), a peroxide isolated from Krameria cytisoides.

MAIN METHODS

The antinociceptive activity of KACY was evaluated using the hot plate, acetic acid and formalin tests. The effects of KACY on heat-induced hemolysis in rat erythrocytes were also evaluated. The in vivo anti-inflammatory assays were performed using the chronic TPA (12-O-tetradecanoylphorbol 13-acetate) method to induce ear edema and carrageenan-kaolin induced arthritis (CKIA). In the CKIA model, the hot plate test was performed, serum samples were obtained for the quantitation of pro-inflammatory (IL-1β, IL-6, IL-12 and TNF-α) and anti-inflammatory (IL-4 and IL-10) cytokines.

KEY FINDINGS

KACY possess antinociceptive effects with comparable activity to naproxen (NPX). KACY inhibited hemolysis (EC50 = 180 μg/mL), in comparison to the untreated group and with a higher potency than NPX (EC50 = 263 μg/mL). KACY at 50 mg/kg decreased inflammation by 38% (chronic TPA-induced edema model) and by 26% (CKIA model), in comparison with the vehicle group and with similar activity to the positive controls 8 mg/kg indomethacin (IND) and 1 mg/kg methotrexate (MTX), respectively. In the CKIA model, KACY increased the release of anti-inflammatory (IL-4 and IL-10) cytokines but reduced the production of pro-inflammatory cytokines (IL-1β, IL-6, IL-12 and TNF-α). KACY at 50 and 100 mg/kg showed antinociceptive effects by 27% and 23%, respectively, in mice with mono-arthritis.

SIGNIFICANCE

KACY might be a good alternative for the treatment of rheumatoid arthritis (RA) due its antinociceptive and anti-inflammatory activities.

An unreported clindamycin adverse reaction: wrist monoarthritis

Clindamycin is a lincosamide antibiotic which is approved for the treatment of Anaerobic, Streptococcal and Staphylococcal infections. There has been an increased interest in the use of clindamycin since it achieves high intracellular levels in phagocytic cells, high levels in bone and appears to have an antitoxin effect against the toxin elaborating strains of streptococci and staphylococci. Clindamycin is considered as a bacteriostatic antibiotic, while it is bactericidal against some strains of Staphylococci, Streptococci and Anaerobes such as B. fragilis. Its major disadvantage is its propensity to cause antibiotic-associated diarrhea. In spite of expanded use of clindamycin in bone infections, the adverse reactions of this antibiotic are minor. Polyarthritis is a rare adverse effect of this antibiotic. In this case report, we studied a 75-year-old male patient with past history of drop attack and subdural hematoma who developed skull osteomyelitis after the surgery. After two weeks of intravenous antibiotic therapy, wound discharge was stopped and the patient was discharged from the hospital with the maintenance oral antibiotic therapy including clindamycin 300 mg q8 h, ciprofloxacin 500 mg q12 h and rifampin 600 mg fasting. Six days after the beginning of oral antibiotics, right wrist monoarthritis was developed. It was unresponsive to nonsteroidal anti-inflammatory drug and improved after decreased doses of clindamycin. As best as we know, monoarthritis was not reported with clindamycin previously.

Monoarthritis Induced by Bupropion Hydrochloride

Bupropion hydrochloride is an inhibitor of dopamine and norepinephrine, which is commonly prescribed for major depression, smoking cessation, and bipolar depression. Here we report a highly unusual case of bupropion induced knee monoarthritis in a bipolar depression patient. With bupropion XL 150 mg for 2 weeks, her left knee began to swell; at the third week, this condition was worsening. The aggravation of the left knee effusion stopped after the discontinuation of bupropion XL. The effusion and swelling disappeared after 15 ml of synovial fluid was drawn out and the effusion has never returned. Analysis of the synovial fluid showed noninflammatory effusion. Her left knee swelling was most likely due to angioedema caused by bupropion XL.