Simvastatin and fluvastatin attenuate trauma-induced cell death and catabolism in human cartilage

Hip joint-preserving strategies for treating osteonecrosis of the femoral head: From nonoperative to operative procedures

Osteonecrosis of the femoral head (ONFH) has an exceedingly high prevalence and disability rate, causing a tremendous socioeconomic burden. The prevalence of ONFH is increasing, while the population of the patients with ONFH is becoming younger. Once the femoral head collapses, treatment becomes difficult and often requires a hip joint replacement, which is not favorable for young patients. Therefore, hip joint-preserving treatments at an early stage of ONFH are particularly important. This study provides a comprehensive review on hip-preserving strategies for treating ONFH, including nonoperative treatments (e.g., protective weight bearing, hyperbaric oxygen, pulsed electromagnetic, extracorporeal shockwave, bisphosphonate, anticoagulants, hypolipidemics, vasodilators, and traditional Chinese medicine) and operative treatments (e.g., core decompression, osteotomy, bone grafting, mesenchymal stem cell transplantation, tantalum rods, and tissue engineering). Nonoperative treatments aim to slow down the progression of the disease and delay the need for joint replacement; however, they usually cannot effectively prevent the progression of the disease, except in cases of small necrosis areas (<10 %). Additionally, nonoperative treatments have unclear mechanisms that require further investigation. In contrast, operative treatments may stop the negative outcomes of necrosis and therefore appear to be more promising. Currently, an emerging area in operative treatments is regenerative medicine, which could promote the generation of bone tissues and blood vessels and restore hip joint function to pre-necrotic levels as much as possible. This review seeks to not only provide an important reference for clinicians when choosing appropriate strategies for treating ONFH but also offer certain guidance for future basic research in developing ONFH treatments.

The translational potential of this article

The incidence of ONFH is increasing, and patients are becoming younger on average. Therefore, the development of hip joint-preserving strategies to treat ONFH at earlier stages is urgently needed, particularly for young patients. However, a comprehensive review is lacking regarding the currently-available hip joint-preserving strategies and their effectiveness. This study is motivated to fill this gap and serve as an important reference for clinicians in choosing appropriate strategies to treat ONFH.

Recent advances in the management of knee osteoarthritis: a narrative review

Knee osteoarthritis (OA) is a common condition that causes pain and reduces the quality of life for many people. It also leads to high health and financial costs. Managing knee OA pain requires using different methods together for the best results. This review overviews current therapeutic options for knee OA pain, focusing on their efficacy, safety, and potential roles in clinical practice. Topical treatments, such as NSAIDs and capsaicin, offer significant pain relief with minimal systemic side effects and are suitable for initial therapy, together with nonpharmacologic interventions like exercise and, when relevant, weight loss. Oral analgesics, including acetaminophen and opioids, have limited efficacy and serious side effects, making them appropriate only for short-term or rescue therapy. Intra-articular injections, such as corticosteroids, hyaluronic acid, and platelet rich plasma, demonstrate varying levels of efficacy and safety. Nutritional supplements, including curcumin, Boswellia serrata, and glucosaminechondroitin combinations, offer modest benefits and are best used as adjuncts to standart treatment. Nonpharmacological treatments, such as transcutaneous electrical nerve stimulation (TENS), acupuncture, and local heat therapy, provide variable pain relief and should be customized based on individual patient responses. Targeted biologic agents, such as antibodies to TNF-α, IL-1, and NGF, hold promise for more precise pain relief; however, further research is required to establish their routine use. Treating knee OA pain should be personalized, combining several methods. Research must continue to improve treatments and make them safer.

Senolytic therapy combining Dasatinib and Quercetin restores the chondrogenic phenotype of human osteoarthritic chondrocytes by the release of pro-anabolic mediators

Cellular senescence is associated with various age-related disorders and is assumed to play a major role in the pathogenesis of osteoarthritis (OA). Based on this, we tested a senolytic combination therapy using Dasatinib (D) and Quercetin (Q) on aged isolated human articular chondrocytes (hACs), as well as in OA-affected cartilage tissue (OARSI grade 1-2). Stimulation with D + Q selectively eliminated senescent cells in both, cartilage explants and isolated hAC. Furthermore, the therapy significantly promoted chondroanabolism, as demonstrated by increased gene expression levels of COL2A1, ACAN, and SOX9, as well as elevated collagen type II and glycosaminoglycan biosynthesis. Additionally, D + Q treatment significantly reduced the release of SASP factors (IL6, CXCL1). RNA sequencing analysis revealed an upregulation of the anabolic factors, inter alia, FGF18, IGF1, and TGFB2, as well as inhibitory effects on cytokines and the YAP-1 signaling pathway, explaining the underlying mechanism of the chondroanabolic promotion upon senolytic treatment. Accordingly, stimulation of untreated hAC with conditioned medium of D + Q-treated cells similarly induced the expression of chondrogenic markers. Detailed analyses demonstrated that chondroanabolic effects could be mainly attributed to Dasatinib, while monotherapeutical application of Quercetin or Navitoclax did not promote the chondroanabolism. Overall, D + Q therapy restored the chondrogenic phenotype in OA hAC most likely by creating a pro-chondroanabolic environment through the reduction of SASP factors and upregulation of growth factors. This senolytic approach could therefore be a promising candidate for further testing as a disease-modifying osteoarthritis drug.

Therapeutic role of aripiprazole in cartilage defects explored through a drug repurposing approach

Articular cartilage has a limited regenerative capacity, resulting in poor spontaneous healing of damaged tissue. Despite various scientific efforts to enhance cartilage repair, no single method has yielded satisfactory results. With rising drug development costs, drug repositioning has emerged as a viable alternative. This study aimed to identify a drug capable of improving cartilage defects by analyzing chondrogenesis-related microarray data from the Gene Expression Omnibus (GEO) public database. We utilized datasets GSE69110, GSE107649, GSE111822, and GSE116173 to identify genes associated with cartilage differentiation, employing StringTie for differential gene expression analysis and extracting drug data from the Drug-Gene Interaction database. Additionally, we aimed to verify the cartilage regeneration potential of the identified drug through experiments using cellular and animal models. We evaluated the effects of aripiprazole on adipose-derived mesenchymal stem cells (ADMSCs) and chondrocytes using qRT-PCR and a 3D pellet culture system. In vivo, we assessed cartilage restoration by combining aripiprazole with a scaffold and implanting it into artificially induced cartilage defects in Sprague-Dawley rats. Subsequent mRNA sequencing provided insights into the mechanistic pathways involved. Our results showed that aripiprazole significantly increased mRNA expression of COL2A1 and SOX9, markers of chondrogenesis, and promoted chondrogenic condensation in vitro. Furthermore, aripiprazole effectively enhanced cartilage regeneration in the rat model. KEGG pathway and Gene Ontology Biological Processes (GOBP) analyses of the mRNA sequencing data revealed that aripiprazole upregulated genes related to ribosomes and cytoplasmic translation, thereby facilitating chondrogenesis. In conclusion, our findings suggest that aripiprazole is a promising candidate for improving damaged cartilage, offering a novel approach to cartilage regeneration.

Causal impact of statins on susceptibility to osteoarthritis: insights from a two-sample Mendelian randomization analysis

BACKGROUND

Osteoarthritis is a widely prevalent cause of pain and disability among older adults. It is an incurable condition, and most treatments are aimed at alleviating symptoms.

AIM

This study aimed to investigate the impact of statins on osteoarthritis by using a two-sample Mendelian randomization approach, using genetic variants associated with statin use as instrumental variables.

METHOD

Information on single nucleotide polymorphisms associated with statin medication was obtained from the FinnGen study, and data on osteoarthritis were sourced from the UK Biobank. The inverse variance weighted method was used as the primary analytical approach for the Mendelian randomization analysis. Sensitivity analyses were conducted to evaluate horizontal pleiotropy and heterogeneity. To examine the genetic relationship between statins and osteoarthritis, linkage disequilibrium score regression-based estimates were used.

RESULTS

Mendelian randomization analysis indicated a positive effect of statin use on the treatment of osteoarthritis (odds ratio 0.951, 95% confidence interval 0.914-0.99, p < 0.05). This conclusion was supported by various Mendelian randomization methods. Sensitivity analyses revealed no significant directional pleiotropy or influential single nucleotide polymorphisms that could compromise the overall causal inference. Linkage disequilibrium score regression-based estimates suggested a modest genetic correlation between statin use and osteoarthritis (Rg = 0.098, Se = 0.034, p < 0.05), thus reinforcing the robustness of the Mendelian randomization analysis.

CONCLUSION

Statins reduce the risk of osteoarthritis, aligning with the results of observational studies. Further research is essential to validate these results and explore the underlying mechanisms in detail.

Assessing the causal associations of different types of statins use and knee/hip osteoarthritis: A Mendelian randomization study

OBJECTIVE

This study comprehensively evaluated the causal relationship between different types of statins use and knee/hip osteoarthritis (OA) using a two-sample and multivariate Mendelian randomization (MR) method.

METHODS

MR analysis was conducted using publicly available summary statistics data from genome-wide association studies (GWAS) to assess the causal associations between total statins use (including specific types) and knee/hip OA. The primary analysis utilized the inverse variance-weighted (IVW) method, with sensitivity analysis conducted to assess robustness. Multivariable MR (MVMR) analysis adjusted for low-density lipoprotein cholesterol (LDL-C), intermediate-density lipoprotein cholesterol (IDL-C), high-density lipoprotein cholesterol (HDL-C), and body mass index (BMI).

RESULTS

The MR analysis revealed a significant inverse association between genetically predicted total statins use and the risk of knee OA (OR = 0.950, 95%CI: 0.920-0.982, p = 0.002) as well as hip OA (OR = 0.932, 95%CI: 0.899-0.966, p <0.001). Furthermore, this study highlighted a reduced risk of knee/hip OA with the use of atorvastatin and simvastatin. Rosuvastatin use was associated with a decreased risk of hip OA but showed no association with knee OA. MVMR results indicated no correlation between exposure factors and outcomes after adjusting for LDL-C or IDL-C. HDL-C may not significantly contribute to statin-induced osteoarthritis, while BMI may play an important role.

CONCLUSION

This study provides compelling evidence of the close relationship between statin use and a reduced risk of knee/hip OA, particularly with atorvastatin and simvastatin. LDL-C and IDL-C may mediate these effects. These findings have important implications for the clinical prevention and treatment of knee/hip OA.

Increase of cell surface vimentin is associated with vimentin network disruption and subsequent stress-induced premature senescence in human chondrocytes

Accumulation of dysfunctional chondrocytes has detrimental consequences on the cartilagehomeostasis and is thus thought to play a crucial role during the pathogenesis of osteoarthritis(OA). However, the underlying mechanisms of phenotypical alteration in chondrocytes areincompletely understood. Here, we provide evidence that disruption of the intracellularvimentin network and consequent phenotypical alteration in human chondrocytes results in anexternalization of the intermediate filament. The presence of the so-called cell surfacevimentin (CSV) on chondrocytes was associated with the severity of tissue degeneration inclinical OA samples and was enhanced after mechanical injury of cartilage tissue. By meansof a doxorubicine-based in vitro model of stress-induced premature senescence (SIPS), wecould confirm the connection between cellular senescence and amount of CSV. AlthoughsiRNA-mediated silencing of CDKN2A clearly reduced the senescent phenotype as well asCSV levels of human chondrocytes, cellular senescence could not be completely reversed.Interestingly, knockdown of vimentin resulted in a SIPS-like phenotype and consequentlyincreased CSV. Therefore, we concluded that the integrity of the intracellular vimentinnetwork is crucial to maintain cellular function in chondrocytes. This assumption could beconfirmed by chemically- induced collapse of the vimentin network, which resulted in cellularstress and enhanced CSV expression. Regarding its biological function, CSV was found to beassociated with enhanced chondrocyte adhesion and plasticity. While osteogenic capacitiesseemed to be enhanced in chondrocytes expressing high levels of CSV, the chondrogenicpotential was clearly compromised. Overall, our study reinforces the importance of thevimentin network in maintenance of the chondrogenic phenotype and introduces CSV as anovel membrane-bound marker of dysfunctional chondrocytes.

Oxidative stress as a key modulator of cell fate decision in osteoarthritis and osteoporosis: a narrative review

During aging and after traumatic injuries, cartilage and bone cells are exposed to various pathophysiologic mediators, including reactive oxygen species (ROS), damage-associated molecular patterns, and proinflammatory cytokines. This detrimental environment triggers cellular stress and subsequent dysfunction, which not only contributes to the development of associated diseases, that is, osteoporosis and osteoarthritis, but also impairs regenerative processes. To counter ROS-mediated stress and reduce the overall tissue damage, cells possess diverse defense mechanisms. However, cellular antioxidative capacities are limited and thus ROS accumulation can lead to aberrant cell fate decisions, which have adverse effects on cartilage and bone homeostasis. In this narrative review, we address oxidative stress as a major driver of pathophysiologic processes in cartilage and bone, including senescence, misdirected differentiation, cell death, mitochondrial dysfunction, and impaired mitophagy by illustrating the consequences on tissue homeostasis and regeneration. Moreover, we elaborate cellular defense mechanisms, with a particular focus on oxidative stress response and mitophagy, and briefly discuss respective therapeutic strategies to improve cell and tissue protection.