Prospects of Disease-Modifying Osteoarthritis Drugs

Animal Models of Osteoarthritis: Updated Models and Outcome Measures 2016-2023

Purpose

Osteoarthritis (OA) is a global musculoskeletal disorder that affects primarily the knee and hip joints without any FDA-approved disease-modifying therapies. Animal models are essential research tools in developing therapies for OA; many animal studies have provided data for the initiation of human clinical trials. Despite this, there is still a need for strategies to recapitulate the human experience using animal models to better develop treatments and understand pathogenesis. Since our last review on animal models of osteoarthritis in 2016, there have been exciting updates in OA research and models. The main purpose of this review is to update the latest animal models and key features of studies in OA research.

Method

We used our existing classification method and screened articles in PubMed and bibliographic search for animal OA models between 2016 and 2023. Relevant and high-cited articles were chosen for inclusion in this narrative review.

Results

Recent studies were analyzed and classified. We also identified ex vivo models as an area of ongoing research. Each animal model offers its own benefit in the study of OA and there are a full range of outcome measures that can be assessed. Despite the vast number of models, each has its drawbacks that have limited translating approved therapies for human use.

Conclusion

Depending on the outcome measures and objective of the study, researchers should pick the best model for their work. There have been several exciting studies since 2016 that have taken advantage of regenerative engineering techniques to develop therapies and better understand OA.

Lay Summary

Osteoarthritis (OA) is a chronic debilitating disease without any cure that affects mostly the knee and hip joints and often results in surgical joint replacement. Cartilage protects the joint from mechanical forces and degrades with age or in response to injury. The many contributing causes of OA are still being investigated, and animals are used for preclinical research and to test potential new treatments. A single consensus OA animal model for preclinical studies is non-existent. In this article, we review the many animal models for OA and provide a much-needed update on studies and model development since 2016.

Network analysis, in vivo, and in vitro experiments identified the mechanisms by which Piper longum L. [Piperaceae] alleviates cartilage destruction, joint inflammation, and arthritic pain

Osteoarthritis (OA) is characterized by irreversible joint destruction, pain, and dysfunction. Piper longum L. [Piperaceae] (PL) is an East Asian herbal medicine with reported anti-inflammatory, analgesic, antioxidant, anti-stress, and anti-osteoporotic effects. This study aimed to evaluate the efficacy of PL in inhibiting pain and progressive joint destruction in OA based on its anti-inflammatory activity, and to explore its potential mechanisms using in vivo and in vitro models of OA. We predicted the potential hub targets and signaling pathways of PL through network analysis and molecular docking. Network analysis results showed that the possible hub targets of PL against OA were F2R, F3, MMP1, MMP2, MMP9, and PTGS2. The molecular docking results predicted strong binding affinities for the core compounds in PL: piperlongumine, piperlonguminine, and piperine. In vitro experiments showed that PL inhibited the expression of LPS-induced pro-inflammatory factors, such as F2R, F3, IL-1β, IL-6, IL-17A, MMP-1, MMP-2, MMP-3, MMP-9, MMP-13, NOS2, PTGS2, PGE2, and TNF-β. These mechanisms and effects were dose-dependent in vivo models. Furthermore, PL inhibited cartilage degradation in an OA-induced rat model. Thus, this study demonstrated that multiple components of PL may inhibit the multilayered pathology of OA by acting on multiple targets and pathways. These findings highlight the potential of PL as a disease-modifying OA drug candidate, which warrants further investigation.

Clinical and Animal Studies of Waist and Knee Scraping Therapy for Knee Osteoarthritis

BACKGROUND

Knee osteoarthritis (KOA) is a degenerative condition with knee pain as the main clinical manifestation. Scraping is one of the commonly used traditional Chinese medicine treatment methods, which activates blood circulation, removes blood stasis, reduces inflammation, and so on. Although scholars have proposed that the synergistic treatment of the waist and knee for KOA is superior to simple knee treatment, there is no relevant reference literature on the application of scraping therapy. Therefore, this study aims to explore the effectiveness and potential mechanisms of waist and knee scraping therapy for treating KOA through clinical and animal studies in order to promote its clinical application.

OBJECTIVE

To explore the clinical efficacy of waist and knee scraping therapy in the treatment of KOA from clinical study and increase animal study on this basis to preliminarily explore its mechanism, providing an objective basis for better treatment of KOA.

METHODS

The clinical study recruited 90 KOA patients and divided them into a control group, a knee scraping group, and a waist and knee scraping group using a random number table method. All patients were evaluated for clinical efficacy, the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC), and Traditional Chinese Medicine Syndrome Score. The KOA rat model was established using the Hulth method. The rats were randomly divided into a control group, KOA group, waist scraping group, knee scraping group, and waist and knee scraping group. During the intervention process of rats, the pain sensitivity threshold was measured, and HE staining was performed on the synovium and cartilage. The protein and mRNA expression levels of TNF-α, IL- 1β, IL-6, PGP9.5, SP and TRPA1, TRPV4, SP, and NGF were measured by Western blot and real-time PCR.

RESULTS

In the clinical study, the clinical efficacy of the 2 scraping groups was significantly higher than that of the control group. The clinical efficacy of the waist and knee scraping group on the 60th day of treatment was significantly higher than that of the knee scraping group. In terms of improving WOMAC scores, all 3 groups had significance; The function and total score of the waist and knee scraping group on the 28th day of treatment, as well as the pain, function, and total score on the 60th day, were lower than those of the knee scraping group. In terms of improving pain while standing, pain when walking on flat ground, and total score, the scraping group had significant differences. The score of heavy limbs in the waist and knee scraping group was lower than that in the knee scraping group. In an animal study, during the 4th week after modeling, there were differences in the pain sensitivity threshold between the KOA group and the waist scraping group compared to the control group, while there were differences in the pain sensitivity threshold between the knee scraping group and the waist and knee scraping group compared to the KOA group. The expression levels of various proteins and genes in the KOA group and waist scraping group increased compared to the control group; The knee scraping group and the waist and knee scraping group were lower than those in the KOA group.

CONCLUSION

Scraping therapy can significantly alleviate knee joint pain and stiffness, improve joint function, and improve clinical efficacy, and the short-term and long-term effects of waist and knee scraping therapy are more significant. The scraping therapy has a definite therapeutic effect on KOA rats, which can improve the threshold of cold hyperalgesia and mechanical hyperalgesia, and the waist and knee scraping therapy is more obvious. This may be related to reducing inflammatory reactions in synovial and ganglion tissues.

A randomized, triple-blinded controlled clinical study with a novel disease-modifying drug combination in equine lameness-associated osteoarthritis

Objective

This study aimed to test a novel treatment combination (TC) (equivalent to sildenafil, mepivacaine, and glucose) with disease-modifying properties compared to Celestone® bifas® (CB) in a randomized triple-blinded phase III clinical study in horses with mild osteoarthritis (OA). Joint biomarkers (reflecting the articular cartilage and subchondral bone remodelling) and clinical lameness were used as readouts to evaluate the treatment efficacy.

Methods

Twenty horses with OA-associated lameness in the carpal joint were included in the study and received either TC (n = 10) or CB (n = 10) drug intra-articularly-twice in the middle carpal joint with an interval of 2 weeks (visit 1 & 2). Clinical lameness was assessed both objectively (Lameness locator) and subjectively (visually). Synovial fluid and serum were sampled for quantification of the extracellular matrix (ECM) neo-epitope joint biomarkers represented by biglycan (BGN²⁶²) and cartilage oligomeric matrix protein (COMP¹⁵⁶). Another two weeks later clinical lameness was recorded, and serum was collected for biomarkers analysis. The overall health status was compared pre and post-intervention by interviewing the trainer.

Results

Post-intervention, SF BGN²⁶² levels significantly declined in TC (P = 0.002) and COMP¹⁵⁶ levels significantly increased in CB (P = 0.002). The flexion test scores improved in the TC compared to CB (P =0.033) and also had an improved trotting gait quality (P =0.044). No adverse events were reported.

Conclusion

This is the first clinical study presenting companion diagnostics assisting in identifying OA phenotype and evaluating the efficacy and safety of a novel disease-modifying osteoarthritic drug.

Stem of Sorbus commixta Hedl. Extract Inhibits Cartilage Degradation and Arthritic Pain in Experimental Model via Anti-Inflammatory Activity

Osteoarthritis (OA) is a widespread joint disease that affects millions of people worldwide. Conventional treatments for OA, including non-steroidal anti-inflammatory drugs (NSAIDs) and steroids, have a risk of various adverse events, including liver, gastrointestinal, cardiovascular, and kidney disease, which are unsatisfactory in their effectiveness. In this study, Sorbus commixta Hedl. Stem extracts (SCE) were evaluated in animal models as potential inhibitors for the progression of OA. Sorbus commixta Hedl., which was found to have substantial anti-inflammatory and antioxidant activities in earlier investigations, has shown potential as a candidate for OA treatment. To mimic human OA symptoms, male rats were injected using sodium iodoacetate (MIA) in their knee joints. SCE significantly reduced MIA-induced weight-bearing loss in rats after the MIA injection and alleviated cartilage degradation and subchondral bone injury caused by MIA. In addition, SCE administration reduced levels of TNF-α and IL-1β such as pro-inflammatory cytokines in serum, as well as the levels of matrix metalloproteinases (MMPs) such as MMP-1, -3, -8 and -13 in the joint cartilage. SCE significantly inhibited the writhing responses in acetic acid-administered mice and was used to quantify pain. In lipopolysaccharide (LPS)-activated RAW264.7, SCE suppressed NO production and reduced the expression of TNF-α, PGE2, IL-6, IL-1β, MMP1, MMP3, MMP8, and MMP-13. Our study showed that SCE alleviated inflammation and cartilage degradation in arthritis through its anti-inflammatory activities on multiple targets.

Failure of cartilage regeneration: emerging hypotheses and related therapeutic strategies

Osteoarthritis (OA) is a disabling condition that affects billions of people worldwide and places a considerable burden on patients and on society owing to its prevalence and economic cost. As cartilage injuries are generally associated with the progressive onset of OA, robustly effective approaches for cartilage regeneration are necessary. Despite extensive research, technical development and clinical experimentation, no current surgery-based, material-based, cell-based or drug-based treatment can reliably restore the structure and function of hyaline cartilage. This paucity of effective treatment is partly caused by a lack of fundamental understanding of why articular cartilage fails to spontaneously regenerate. Thus, research studies that investigate the mechanisms behind the cartilage regeneration processes and the failure of these processes are critical to instruct decisions about patient treatment or to support the development of next-generation therapies for cartilage repair and OA prevention. This Review provides a synoptic and structured analysis of the current hypotheses about failure in cartilage regeneration, and the accompanying therapeutic strategies to overcome these hurdles, including some current or potential approaches to OA therapy.

Biomarkers for osteoarthritis: Current status and future prospects

Osteoarthritis (OA) is the most common form of arthritis globally and a major cause of pain, physical disability, and loss of economic productivity, with currently no causal treatment available. This review article focuses on current research on OA biomarkers and the potential for using biomarkers in future clinical practice and clinical trials of investigational drugs. We discuss how biomarkers, specifically soluble ones, have a long path to go before reaching clinical standards of care. We also discuss how biomarkers can help in phenotyping and subtyping to achieve enhanced stratification and move toward better-designed clinical trials. We also describe how biomarkers can be used for molecular endotyping and for determining the clinical outcomes of investigational cell-based therapies. Biomarkers have the potential to be developed as surrogate end points in clinical trials and help private-public consortia and the biotechnology and pharmaceutical industries develop more effective and targeted personalized treatments and enhance clinical care for patients with OA.

Efficacy, Safety, and Accuracy of Intra-articular Therapies for Hand Osteoarthritis: Current Evidence

The lifetime risk of symptomatic hand osteoarthritis (OA) is 39.8%, with one in two women and one in four men developing the disease by age 85 years and no disease-modifying drug (DMOAD) available so far. Intra-articular (IA) therapy is one of the options commonly used for symptomatic alleviation of OA disease as it can circumvent systemic exposure and potential side effects of oral medications. The current narrative review focuses on the efficacy and safety profiles of the currently available IA agents in hand OA (thumb-base OA or interphalangeal OA) such as corticosteroids and hyaluronic acid (HA), as well as the efficacy and safety of IA investigational injectates in phase 2/3 clinical trials such as prolotherapy, platelet-rich plasma, stem cells, infliximab, interferon-? and botulinum toxin, based on the published randomized controlled trials on PubMed database. The limited published literature revealed the short-term symptomatic benefits of corticosteroids in interphalangeal OA while long-term data are lacking. Most of the short-term studies showed no significant difference between corticosteroids and hyaluronic acid in thumb-base OA, usually with a faster onset of pain relief in the corticosteroid group and a slower but greater (statistically insignificant) pain improvement in the HA group. The majority of studies in investigational agents were limited by small sample size, short-term follow-up, and presence of serious side effects. In addition, we reported higher accuracy rates of drug administrations under imaging guidance than landmark guidance (blind method), and then briefly describe challenges for the long-term efficacy and prospects of IA therapeutics.

Repurposed and investigational disease-modifying drugs in osteoarthritis (DMOADs)

In spite of a major public health burden with increasing prevalence, current osteoarthritis (OA) management is largely palliative with an unmet need for effective treatment. Both industry and academic researchers have invested a vast amount of time and financial expense to discover the first diseasing-modifying osteoarthritis drugs (DMOADs), with no regulatory success so far. In this narrative review, we discuss repurposed drugs as well as investigational agents which have progressed into phase II and III clinical trials based on three principal endotypes: bone-driven, synovitis-driven and cartilage-driven. Then, we will briefly describe the recent failures and lessons learned, promising findings from predefined post hoc analyses and insights gained, novel methodologies to enhance future success and steps underway to overcome regulatory hurdles.