Can low-dose methotrexate reduce effusion-synovitis and symptoms in patients with mid- to late-stage knee osteoarthritis? Study protocol for a randomised, double-blind, and placebo-controlled trial

Methotrexate and the Risk of Dementia: A Two-Sample Mendelian Randomization Study

INTRODUCTION

Recent studies have suggested a potential association between methotrexate use and an increased risk of dementia. However, the causal relationship between methotrexate and dementia remains unclear. This study aims to investigate the potential causal effect of methotrexate use on the risk of dementia using a two-sample Mendelian randomization (TSMR) approach.

METHODS

We conducted a TSMR study using summary statistics from genome-wide association studies (GWAS) of methotrexate use and dementia. We obtained genetic instruments for methotrexate use from a large-scale GWAS meta-analysis and genetic instruments for dementia from a separate GWAS meta-analysis. We performed several statistical analyses, including inverse-variance weighted (IVW), weighted median (WM1), weighted mode (WM2), and MR-Egger regression methods, to estimate the causal effect of methotrexate on dementia risk.

RESULTS

Our TSMR analysis showed a significant positive association between genetic predisposition to methotrexate use and dementia risk. The IVW method estimated a causal odds ratio (OR) of 0.476 [95% confidence interval (CI) 0.362-0.626] per unit increase in the log odds ratio of methotrexate use. WM1, WM2, and MR-Egger methods provided consistent results.

CONCLUSION

The findings of this mendelian randomization (MR) study suggest a potential causal effect of methotrexate use on the risk of dementia. However, further research is needed to validate these findings and explore the underlying mechanisms. Since methotrexate is widely prescribed for various autoimmune diseases, a better understanding of its potential impact on dementia risk is crucial for optimizing treatment strategies and addressing potential adverse effects.

Update on recent developments in imaging of inflammation in osteoarthritis: a narrative review

Synovitis is an important component of the osteoarthritis (OA) disease process, particularly regarding the "inflammatory phenotype" of OA. Imaging plays an important role in the assessment of synovitis in OA with MRI and ultrasound being the most deployed imaging modalities. Contrast-enhanced (CE) MRI, particularly dynamic CEMRI (DCEMRI) is the ideal method for synovitis assessment, but for several reasons CEMRI is not commonly performed for OA imaging in general. Effusion-synovitis and Hoffa-synovitis are commonly used as surrogate markers of synovitis on non-contrast-enhanced (NCE) MRI and have been used in many epidemiological observational studies of knee OA. Several semiquantitative MRI scoring systems are available for the evaluation of synovitis in knee OA. Synovitis can be a target tissue for disease-modifying OA drug (DMOAD) clinical trials. Both MRI and ultrasound may be used to determine the eligibility and assess the therapeutic efficacy of DMOAD approaches. Ultrasound is mostly used for evaluation of synovitis in hand OA, while MRI is typically used for larger joints, namely knees and hips. The role of other modalities such as CT (including dual-energy CT) and nuclear medicine imaging (such as positron-emission tomography (PET) and its hybrid imaging) is limited in the context of synovitis assessment in OA. Despite research efforts to develop NCEMRI-based synovitis evaluation methods, these typically underestimate the severity of synovitis compared to CEMRI, and thus more research is needed before we can rely only on NCEMRI.

Current Approaches to Four Challenging Pain Syndromes

During a conference of pain specialists, some of the experts addressed the potential management of four prevalent but difficult painful conditions, namely, chronic postsurgical pain (CPSP), knee osteoarthritis, chest trauma, and facet joint arthropathy. In all cases, the conditions posed challenges in accurate diagnoses as well as safe, effective treatments, especially using locoregional blocks. It is not clear why some surgical patients develop CPSP and others do not, although some risk factors have been identified. More importantly, the transitional phase of pain from acute to chronic deserves greater scrutiny. It appears as if more aggressive and more effective perioperative and postoperative analgesia could help mitigate or possibly prevent CPSP. Knee osteoarthritis is prevalent but is often managed pharmacologically and then with joint replacement; many patients simply live with the condition which can be viewed as a disease of the entire joint. New approaches with intra-articular injections of hyaluronic acid, platelet-rich plasma, and botulinum toxin may provide safe, effective, and durable pain control. Chest trauma can be extremely painful and a source of morbidity, but its management tends to rely on watchful waiting and drug therapy. New approaches to regional nerve blocks can be beneficial and may reduce troublesome symptoms such as the inability to cough or clear the lungs. Facet joint arthropathy is very prevalent among older people but is not completely clarified. It may be the source of intense pain with limited management strategies. The role of nerve blocks in facet joint arthropathy is an important new addition to the armamentarium of pain management, particularly for geriatric patients.

Could hypoxia rehabilitate the osteochondral diseased interface? Lessons from the interplay of hypoxia and purinergic signals elsewhere

The osteochondral unit comprises the articular cartilage (90%), subchondral bone (5%) and calcified cartilage (5%). All cells present at the osteochondral unit that is ultimately responsible for matrix production and osteochondral homeostasis, such as chondrocytes, osteoblasts, osteoclasts and osteocytes, can release adenine and/or uracil nucleotides to the local microenvironment. Nucleotides are released by these cells either constitutively or upon plasma membrane damage, mechanical stress or hypoxia conditions. Once in the extracellular space, endogenously released nucleotides can activate membrane-bound purinoceptors. Activation of these receptors is fine-tuning regulated by nucleotides' breakdown by enzymes of the ecto-nucleotidase cascade. Depending on the pathophysiological conditions, both the avascular cartilage and the subchondral bone subsist to significant changes in oxygen tension, which has a tremendous impact on tissue homeostasis. Cell stress due to hypoxic conditions directly influences the expression and activity of several purinergic signalling players, namely nucleotide release channels (e.g. Cx43), NTPDase enzymes and purinoceptors. This review gathers experimental evidence concerning the interplay between hypoxia and the purinergic signalling cascade contributing to osteochondral unit homeostasis. Reporting deviations to this relationship resulting from pathological alterations of articular joints may ultimately unravel novel therapeutic targets for osteochondral rehabilitation. At this point, one can only hypothesize how hypoxia mimetic conditions can be beneficial to the ex vivo expansion and differentiation of osteo- and chondro-progenitors for auto-transplantation and tissue regenerative purposes.

A review of osteoarthritis signaling intervention using small-molecule inhibitors

Numerous small-molecule inhibitors (SMIs) have been approved as adjuvant or first-line therapies for malignancies. Based on cancer treatment using SMIs, next-generation SMIs that can be used to optimize the therapeutic index, overcome drug resistance, and establish combination therapies are in development. Osteoarthritis (OA) is the most common chronic joint disease with senescence, and there are various approaches to OA treatment; however, the gold standard treatment is controversial. Therefore, in this manuscript, we demonstrated the potential of using SMIs in OA treatment and described the general strategies for using SMIs in OA treatment.

New Trends in Pharmacological Treatments for Osteoarthritis

Osteoarthritis (OA) is the leading cause of function loss and disability among the elderly, with significant burden on the individual and society. It is a severe disease for its high disability rates, morbidity, costs, and increased mortality. Multifactorial etiologies contribute to the occurrence and development of OA. The heterogeneous condition poses a challenge for the development of effective treatment for OA; however, emerging treatments are promising to bring benefits for OA management in the future. This narrative review will discuss recent developments of agents for the treatment of OA, including potential disease-modifying osteoarthritis drugs (DMOADs) and novel therapeutics for pain relief. This review will focus more on drugs that have been in clinical trials, as well as attractive drugs with potential applications in preclinical research. In the past few years, it has been realized that a complex interaction of multifactorial mechanisms is involved in the pathophysiology of OA. The authors believe there is no miracle therapeutic strategy fitting for all patients. OA phenotyping would be helpful for therapy selection. A variety of potential therapeutics targeting inflammation mechanisms, cellular senescence, cartilage metabolism, subchondral bone remodeling, and the peripheral nociceptive pathways are expected to reshape the landscape of OA treatment over the next few years. Precise randomized controlled trials (RCTs) are expected to identify the safety and efficacy of novel therapies targeting specific mechanisms in OA patients with specific phenotypes.