Management of Knee Osteoarthritis: What Internists Need to Know

MiR-146b-5p enriched bioinspired exosomes derived from fucoidan-directed induction mesenchymal stem cells protect chondrocytes in osteoarthritis by targeting TRAF6

Osteoarthritis (OA) is a common degenerative joint disease characterized by progressive cartilage degradation and inflammation. In recent years, mesenchymal stem cells (MSCs) derived exosomes (MSCs-Exo) have attracted widespread attention for their potential role in modulating OA pathology. However, the unpredictable therapeutic effects of exosomes have been a significant barrier to their extensive clinical application. In this study, we investigated whether fucoidan-pretreated MSC-derived exosomes (F-MSCs-Exo) could better protect chondrocytes in osteoarthritic joints and elucidate its underlying mechanisms. In order to evaluate the role of F-MSCs-Exo in osteoarthritis, both in vitro and in vivo studies were conducted. MiRNA sequencing was employed to analyze MSCs-Exo and F-MSCs-Exo, enabling the identification of differentially expressed genes and the exploration of the underlying mechanisms behind the protective effects of F-MSCs-Exo in osteoarthritis. Compared to MSCs-Exo, F-MSCs-Exo demonstrated superior effectiveness in inhibiting inflammatory responses and extracellular matrix degradation in rat chondrocytes. Moreover, F-MSCs-Exo exhibited enhanced activation of autophagy in chondrocytes. MiRNA sequencing of both MSCs-Exo and F-MSCs-Exo revealed that miR-146b-5p emerged as a promising candidate mediator for the chondroprotective function of F-MSCs-Exo, with TRAF6 identified as its downstream target. In conclusion, our research results demonstrate that miR-146b-5p encapsulated in F-MSCs-Exo effectively inhibits TRAF6 activation, thereby suppressing inflammatory responses and extracellular matrix degradation, while promoting chondrocyte autophagy for the protection of osteoarthritic cartilage cells. Consequently, the development of a therapeutic approach combining fucoidan with MSC-derived exosomes provides a promising strategy for the clinical treatment of osteoarthritis.

Placebo Response to Oral Administration in Osteoarthritis Clinical Trials and Its Associated Factors: A Model-Based Meta-analysis

IMPORTANCE

In osteoarthritis (OA) clinical trials, a placebo is often used as control. Therefore, a thorough understanding of the placebo response is important for guiding drug development in OA.

OBJECTIVE

To develop an oral placebo response model for OA.

DATA SOURCES

PubMed, EMBASE, and Cochrane Library databases were searched systematically from January 1, 1991, to July 2, 2022.

STUDY SELECTION

Randomized double-blind placebo-controlled trials of patients with primary OA were included. The interventions and placebo were administered orally. A total of 3032 trials were identified; of these, 130 (4.3%) met the inclusion criteria.

DATA EXTRACTION AND SYNTHESIS

Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, dosage form of the placebo, sample size, proportion of patients who previously used nonsteroidal anti-inflammatory drugs, publication year, intervention categories, Kellgren-Lawrence grades, proportion of White patients, duration of pain, funding source, and risk of bias were extracted. A model-based meta-analysis was used to evaluate the time course of the placebo response in OA treatment and estimate the influencing factors. For subgroup analyses, a meta-analysis with a random-effects model was used to summarize the typical values of the model parameters and their SEs.

MAIN OUTCOMES AND MEASURES

The primary end point was the time course of the oral placebo response on the WOMAC pain, stiffness, and function subscale scores.

RESULTS

The 130 trials selected for analysis included 12 673 participants (mean age, 59.9 years; 68.9% women). The baseline scores of WOMAC pain, stiffness, and function subscales were found to be significantly associated with the placebo response. The placebo response reached 90% of its maximum response between 5 and 7 weeks. The placebo responses on the WOMAC subscales were also associated with the sample size, proportion of patients who had previously used nonsteroidal anti-inflammatory drugs, intervention drugs, and publication year.

CONCLUSIONS AND RELEVANCE

In this study, an oral placebo response model of OA was developed that may quantitatively describe the placebo response at different baseline levels of symptoms. The findings may provide valuable references for future clinical trial design and decision-making.

Patient characteristics, pain treatment patterns, and incidence of total joint replacement in a US population with osteoarthritis

BACKGROUND

Currently available medications for chronic osteoarthritis pain are only moderately effective, and their use is limited in many patients because of serious adverse effects and contraindications. The primary surgical option for osteoarthritis is total joint replacement (TJR). The objectives of this study were to describe the treatment history of patients with osteoarthritis receiving prescription pain medications and/or intra-articular corticosteroid injections, and to estimate the incidence of TJR in these patients.

METHODS

This retrospective, multicenter, cohort study utilized health plan administrative claims data (January 1, 2013, through December 31, 2019) of adult patients with osteoarthritis in the Innovation in Medical Evidence Development and Surveillance Distributed Database, a subset of the US FDA Sentinel Distributed Database. Patients were analyzed in two cohorts: those with prevalent use of "any pain medication" (prescription non-steroidal anti-inflammatory drugs [NSAIDs], opioids, and/or intra-articular corticosteroid injections) using only the first qualifying dispensing (index date); and those with prevalent use of "each specific pain medication class" with all qualifying treatment episodes identified.

RESULTS

Among 1 992 670 prevalent users of "any pain medication", pain medications prescribed on the index date were NSAIDs (596 624 [29.9%] patients), opioids (1 161 806 [58.3%]), and intra-articular corticosteroids (323 459 [16.2%]). Further, 92 026 patients received multiple pain medications on the index date, including 71 632 (3.6%) receiving both NSAIDs and opioids. Altogether, 20.6% of patients used an NSAID at any time following an opioid index dispensing and 17.2% used an opioid following an NSAID index dispensing. The TJR incidence rates per 100 person-years (95% confidence interval [CI]) were 3.21 (95% CI: 3.20-3.23) in the "any pain medication" user cohort, and among those receiving "each specific pain medication class" were NSAIDs, 4.63 (95% CI: 4.58-4.67); opioids, 7.45 (95% CI: 7.40-7.49); and intra-articular corticosteroids, 8.05 (95% CI: 7.97-8.13).

CONCLUSIONS

In patients treated with prescription medications for osteoarthritis pain, opioids were more commonly prescribed at index than NSAIDs and intra-articular corticosteroid injections. Of the pain medication classes examined, the incidence of TJR was highest in patients receiving intra-articular corticosteroids and lowest in patients receiving NSAIDs.

The use of platelet-rich plasma in management of musculoskeletal pain: a narrative review

Musculoskeletal pain is the most common pain reported by patients. Platelet-rich plasma (PRP) is widely used to treat musculoskeletal pain. However, the efficacy of PRP to treat this pain remains controversial. This review highlights the application of PRP in the treatment of musculoskeletal pain. PRP treatment appears to reduce pain and improve function in patients with musculoskeletal pain. However, there are limitations to the currently published studies. These limitations include the PRP preparation methods, type of activators, types of pathology to be treated, methods and times of administration, and association of PRP with other treatments.

Glucocorticoid caused lactic acid accumulation and damage in human chondrocytes via ROS-mediated inhibition of Monocarboxylate Transporter 4

Osteoarthritis (OA) is a common joint disease lacking effective treatments. Dexamethasone (Dex) is often used to relieve joint pain. However, the adverse effects of Dex on cartilage can't be ignored. This study aimed to investigate the effect of Dex on articular cartilage and its mechanism by in vitro and in vivo experiments. The results showed that intra-articular injection with Dex damaged the matrix synthesis of cartilage. In vitro, Dex induced human chondrocytes mitochondrial dysfunction and increased reactive oxygen species (ROS) level, while down-regulated or unchanged key glycolysis genes, but increased lactic acid (LA) concentration. It was showed that high concentrations of LA induced chondrocytes apoptosis. Mechanistically, monocarboxylate transporter 4 (MCT4) was inhibited by Dex and had a significant negative correlation with ROS level. Further results showed that the trimethyl-histone H3-K4 (H3K4me3) level of MCT4 was reduced by Dex, and the ROS scavenger N-Acetyl-L-cysteine (NAC) and α-ketoglutarate (α-KG) alleviated the Dex-induced obstruction of matrix synthesis and high level of ROS by up-regulating the H3K4me3 level of MCT4 and its expression. In conclusion, Dex exhibited harm to cartilage, shown as mitochondrial dysfunction and increased ROS. The latter further caused LA accumulation in chondrocytes via decreasing the H3K4me3 level of MCT4 and its expression, which may account for the long-term side effects of Dex on chondrocytes. And α-KG may be used as an auxiliary drug to weaken the toxic effect of Dex on cartilage.

A Topical Botanical Ointment for Self-Reported Hip and/or Knee Pain: A Randomized Placebo-Controlled Clinical Trial

Joint pain is a common ailment among adults worldwide. Six men and 14 women (aged 51 ± 10 years) with self-reported joint pain were randomly assigned, using a cross-over design, to a botanical ointment (Yeahhh Baby!®) or placebo, twice daily for 14 days. Subjects completed questionnaires regarding their joint pain and discomfort (eg, WOMAC and subjective pain using a visual analog scale [VAS]) each evening and underwent a washout period of two weeks before crossing into the other condition. Pain and discomfort scores improved for subjects when using Yeahhh Baby!® ointment from day 1 to the average of days 2-15. For certain measures, similar, albeit insignificant, improvements were noted when subjects used the placebo—demonstrating the powerful placebo effect. Specifically, with Yeahhh Baby!® ointment, effects were noted for WOMAC pain ( P = .008), WOMAC physical function ( P = .024), WOMAC total ( P = .019), and VAS mood interference ( P = .042). The most pronounced improvement was noted for WOMAC pain ( P = .048), with a 25% reduction observed with Yeahhh Baby!®, with a 10% reduction noted for placebo. These findings indicate that, as compared to a placebo, Yeahhh Baby!® ointment may provide relief to individuals suffering from joint pain in their knees and/or hips.

Comparison between Intra-Articular Injection of Infrapatellar Fat Pad (IPFP) Cell Concentrates and IPFP-Mesenchymal Stem Cells (MSCs) for Cartilage Defect Repair of the Knee Joint in Rabbits

Mesenchymal stem cells (MSCs) have emerged as a promising therapeutic method in regenerative medicine. Our previous research adopted a simple nonenzymatic strategy for the preparation of a new type of ready-to-use infrapatellar fat pad (IPFP) cell concentrates. The aim of this study was to compare the therapeutic efficacy of intra-articular (IA) injection of autologous IPFP cell concentrates and allogeneic IPFP-MSCs obtained from these concentrates in a rabbit articular cartilage defect model. IPFP-MSCs sprouting from the IPFP cell concentrates were characterized via flow cytometry as well as based on their potential for differentiation into adipocytes, osteoblasts, and chondrocytes. In the rabbit model, cartilage defects were created on the trochlear groove, followed by treatment with IPFP cell concentrates, IPFP-MSCs, or normal saline IA injection. Distal femur samples were evaluated at 6 and 12 weeks posttreatment via macroscopic observation and histological assessment based on the International Cartilage Repair Society (ICRS) macroscopic scoring system as well as the ICRS visual histological assessment scale. The macroscopic score and histological score were significantly higher in the IPFP-MSC group compared to the IPFP cell concentrate group at 12 weeks. Further, both treatment groups had higher scores compared to the normal saline group. In comparison to the latter, the groups treated with IPFP-MSCs and IPFP cell concentrates showed considerably better cartilage regeneration. Overall, IPFP-MSCs represent an effective therapeutic strategy for stimulating articular cartilage regeneration. Further, due to the simple, cost-effective, nonenzymatic, and safe preparation process, IPFP cell concentrates may represent an effective alternative to stem cell-based therapy in the clinic.

Facile Synthesis of Hollow MnO2 Nanoparticles for Reactive Oxygen Species Scavenging in Osteoarthritis

Osteoarthritis (OA) is a progressive degenerative joint disease whose molecular mechanism has not been revealed clearly, and there is still no effective approach to cure OA completely. Recently, reactive oxygen species (ROS) are exposed as an important mediator of OA's inflammatory response, and it has been regarded as a therapeutic target for OA treatment. MnO₂ nanoparticles possess good biocompatibility and can act as an artificial nanoenzyme to scavenge ROS in various diseases effectively. In this study, the modified Stöber method was applied to synthesize hollow MnO₂ (H-MnO₂) and H-MnO₂ was modified with NH₂-PEG-NH₂, which possesses excellent biological stability and biocompatibility. It induced a change in the articular cartilage structure changes in vivo, with the knee tissue staining and micro-CT scanning of the whole knee suggesting that H-MnO₂ nanoparticles could effectively remove ROS and significantly relieve the inflammatory response of OA without obvious side effects. This study reveals the therapeutic effects of MnO₂-based nanomedicine toward OA, which provides potential alternative therapeutic options for patients with inflammation tissue.