A closer look at osteoarthritis

The Role of Alarmins in the Pathogenesis of Rheumatoid Arthritis, Osteoarthritis, and Psoriasis

Alarmins are immune-activating factors released after cellular injury or death. By secreting alarmins, cells can interact with immune cells and induce a variety of inflammatory responses. The broad family of alarmins involves several members, such as high-mobility group box 1, S100 proteins, interleukin-33, and heat shock proteins, among others. Studies have found that the concentrations and expression profiles of alarmins are altered in immune-mediated diseases. Furthermore, they are involved in the pathogenesis of inflammatory conditions. The aim of this narrative review is to present the current evidence on the role of alarmins in rheumatoid arthritis, osteoarthritis, and psoriasis. We discuss their potential involvement in mechanisms underlying the progression of these diseases and whether they could become therapeutic targets. Moreover, we summarize the impact of pharmacological agents used in the treatment of these diseases on the expression of alarmins.

Probing the antinociceptive and therapeutic potential of probiotics in managing temporomandibular joint arthritis

This literature review explored the antinociceptive and therapeutic effects of probiotic therapy (PT) in the treatment of arthritic conditions affecting the temporomandibular joint (TMJ). Indexed databases were searched without time and language restrictions up to and including February 2023, to identify studies addressing the question: "Is PT effective for the management of TMJ arthritis?" The following keywords were used in different combinations with Boolean operators: arthritis, osteoarthritis, pain, probiotic, rheumatoid, temporomandibular disorders, and temporomandibular joint. Original clinical and experimental studies assessing the therapeutic efficacy of PT in the management of osteoarthritis were eligible for inclusion. Letters to the editor, reviews, commentaries, perspectives, and expert opinions were not sought. The structure of the current review was tailored to encapsulate relevant information. A total of 297 relevant studies were identified during the initial literature search, and the full text and reference lists of these studies were scrutinized. To date, the potential role of PT in managing osteoarthritis of the TMJ region remains uninvestigated. No clinical trials in the indexed literature have assessed the efficacy of PT in managing TMJ arthritis; however, this finding does not preclude a potential role of probiotics as antinociceptive and therapeutic agents in susceptible populations.

Association between weight-adjusted-waist index and the prevalence of rheumatoid arthritis and osteoarthritis: a population-based study

INTRODUCTION

The weight-adjusted-waist Index (WWI), an innovative metric for assessing obesity, exhibits superior efficacy in appraising lean muscle and adipose tissue mass relative to both the Body Mass Index (BMI) and Waist Circumference (WC). The objective of this research paper is to investigate the correlation between WWI and the incidence of Rheumatoid Arthritis (RA) and Osteoarthritis (OA).

METHODS

In this population-based study, we collected data from adult participants aged 20-80 years using the National Health and Nutrition Examination Survey (NHANES) conducted between 2011 and 2020 to analyze the association between WWI and the occurrence of RA and OA. NHANES, a nationally representative cross-sectional survey, is designed to evaluate the health and nutritional status of the U.S.

POPULATION

The current research incorporates an extensive, nationally representative sample of U.S. adults, utilizing weighted multivariate linear regression and smoothed curve fitting techniques to examine linear and non-linear relationships. Threshold effects were determined through a two-part linear regression model. Additionally, subgroup analyses and interaction tests were conducted to explore the connection between WWI and the incidence of RA and OA.

RESULTS

Our findings reveal a linear positive correlation between WWI and OA prevalence, indicating that an increase in WWI is linked to a heightened risk of OA. Conversely, a non-linear relationship was observed between WWI and RA prevalence, exhibiting a significant threshold effect with a saturation value of 11.21 cm/√kg. A positive association was detected to the left of the saturation point, while no significant association was present between the two variables to the right of the saturation point, suggesting a complex non-linear relationship between RA prevalence and WWI.

CONCLUSIONS

This investigation demonstrates a positive linear association between WWI and OA prevalence, as well as a complex non-linear relationship with RA prevalence in U.S. adults aged 20-80 years.

Activity limitation and participation restriction in Osteoarthritis and Rheumatoid arthritis: findings based on the National Health and Nutritional Examination Survey

Background

Osteoarthritis (OA) and Rheumatoid arthritis (RA) are the most common joint diseases leading to chronic pain and disability. Given the chronicity and disabling nature of OA and RA, they are likely to influence full participation of individuals in the society. An activity limitation occurs when a person has difficulty executing an activity; a participation restriction is experienced when a person has difficulty participating in a real-life situation. The aim of this study was to examine the associations between OA and RA and the domains of activity limitation and participation restriction.

Methods

A cross-sectional study design comprised 3604 adults from the 2009 to 2018 National Health and Nutrition Examination Survey (NHANES). All participants aged ≥ 20 years with complete data were included. Activity limitation and participation restriction were assessed by reported difficulty in performing 14 tasks selected from Physical Functioning Questionnaire. Data on OA and RA were obtained from Medical Conditions Questionnaire. Weighted logistic regression model was used to examine the associations between OA and RA and the selected tasks.

Results

Over 36% of participants had limitations. Both OA (OR = 2.11) and RA (OR = 2.36) were positively associated with activity limitation and participation restriction (p < 0.001). Poor or fair health was associated with difficulty in physical functioning, with highest odds observed in leisure activities (OR = 2.05), followed by difficulty in attending social events (OR = 1.99), walking for a quarter mile (OR = 1.97), preparing meals (OR = 1.93) and walking up ten steps (OR = 1.92).

Conclusion

Adults with OA and RA had nearly similar odds of having activity limitations and participation restrictions. Difficulty in executing most activities of daily living (ADLs) has significant association with poor or fair health. Holistic interdisciplinary care to individuals with OA or RA focusing on ADLs and environmental factors may improve health status.

Semaphorin 3A mitigates lipopolysaccharide-induced chondrocyte inflammation, apoptosis and extracellular matrix degradation by binding to Neuropilin-1

Semaphorin 3A (SEMA3A) and its receptor neuropilin-1 (NRP-1) are expressed low in chondrocytes under stress, and overexpressing SEMA3A reduces pro-inflammatory cytokine release. This study was aimed at exploring whether SEMA3A participates in lipopolysaccharide (LPS)-induced chondrocyte inflammation, apoptosis and extracellular matrix (ECM) degradation. SEMA3A and NRP-1 expression in LPS-induced ATDC5 cells was determined with RT-qPCR and western blotting. Following stimulation with LPS in the absence or presence of SEMA3A overexpression, the viability of ATDC5 cells was observed through CCK-8 assay. RT-qPCR and western blot were performed to detect the expression of pro-inflammatory cytokines. ATDC5 cell apoptosis was observed through TUNEL, and apoptosis-related proteins were assayed. Expression of ECM-related proteins was measured by RT-qPCR and western blotting. Additionally, the binding of SEMA3A to NRP-1 was verified by co-immunoprecipitation. After interference with NRP-1, cell viability, inflammation and ECM degradation were examined in LPS-induced ATDC5 cells with SEMA3A overexpression. Results revealed that SEMA3A expression in ATDC5 cells decreased following stimulation with LPS. Overexpressing SEMA3A improved cell viability and reduced the inflammatory injury of LPS-stimulated ATDC5 cells. Moreover, SEMA3A overexpression alleviated LPS-induced apoptosis and ECM degradation of ATDC5 chondrocytes. SEMA3A and NRP-1 bound to each other in ATDC5 cells. NRP-1 interference crippled the ameliorative effect of SEMA3A overexpression on LPS-induced chondrocyte inflammation, apoptosis and ECM degradation. To conclude, SEMA3A binds to NRP-1, mitigating LPS-induced chondrocyte inflammation, apoptosis and ECM degradation. This study elucidated the role of SEMA3A in osteoarthritis and illustrated its action mechanism involving NRP-1.

Osteoarthritis treatment: Decreasing pain, improving mobility

Osteoarthritis (OA) is the most common articular disease. The condition results in bone-on-bone contact, stiffness, pain, and decreased mobility. By the year 2050, 40 million individuals will be severely disabled because of OA, and there will be over 130 million individuals suffering from OA worldwide.