Biomechanics of Chondrocytes and Chondrons in Healthy Conditions and Osteoarthritis: A Review of the Mechanical Characterisations at the Microscale

Inverse L-shaped association of triglyceride glucose index with all-cause and cerebral cardiovascular-related mortality in osteoarthritis patients: a cohort of 4145 patients

BACKGROUND

Currently, osteoarthritis (OA) is recognized as a systemic disease, wherein metabolic disturbances play a part in joint degeneration and elevated risk of mortality. This study investigates the prognostic value of the triglyceride-glucose (TyG) index in determining all-cause and cerebral cardiovascular mortality among OA patients, accentuating the necessity for customized interventions.

METHODS

A cohort of osteoarthritis patients from the 1999-2018 NHANES was linked to the 2019 National Death Index (NDI) for mortality confirmation. TyG index correlation with all-cause and cerebral cardiovascular mortality was assessed using Cox regression and Kaplan-Meier curves. Non-linear associations were examined with restricted cubic splines, and a two-piecewise Cox model was built around the inflection point.

RESULTS

A total of 4145 OA patients were followed for a median of 89 months, during which 1109 all-cause deaths and 427 cerebral cardiovascular-related deaths were observed. Restricted cubic splines showed an inverse L-shaped relationship between the TyG index and both types of mortality. The critical point was identified as 9.48, with a 1-unit increase associated with a 71% and 91% rise in adjusted all-cause and cerebral cardiovascular mortality, respectively (HR 1.71; 95% CI 1.30, 2.26 and HR 1.91; 95% CI 1.28, 2.86). Subgroup analyses revealed significant associations between the TyG index and elevated mortality risks among non-white OA patients and those with concurrent diabetes.

CONCLUSION

In OA patients, the TyG index and mortality (both all-cause and cerebral cardiovascular) share an inverse L-shaped relationship, with identified thresholds at 9.48. This threshold offers valuable insight for risk assessment, thus promoting a shift towards personalized healthcare strategies founded on metabolic status for enhanced outcomes within OA populations. Key points • The TyG index predicts all-cause and cerebral cardiovascular mortality in OA patients. • An inverse L-shaped relationship between the TyG index and mortality was found, with a critical threshold of 9.48. • Non-white OA patients and those with diabetes show significant associations with elevated mortality risks, highlighting the importance of personalized care.

Rethinking Osteoarthritis Management: Synergistic Effects of Chronoexercise, Circadian Rhythm, and Chondroprotective Agents

Osteoarthritis (OA) is a chronic and debilitating joint disease characterized by progressive cartilage degeneration for which no definitive cure exists. Conventional management approaches often rely on fragmented and poorly coordinated pharmacological and non-pharmacological interventions that are inconsistently applied throughout the disease course. Persistent controversies regarding the clinical efficacy of chondroprotective agents, frequently highlighted by pharmacovigilance agencies, underscore the need for a structured evidence-based approach. Emerging evidence suggests that synchronizing pharmacotherapy and exercise regimens with circadian biology may optimize therapeutic outcomes by addressing early pathological processes, including low-grade inflammation, oxidative stress, and matrix degradation. Recognizing the influence of the chondrocyte clock on these processes, this study proposes a 'prototype' for a novel framework that leverages the circadian rhythm-aligned administration of traditional chondroprotective agents along with tailored, accessible exercise protocols to mitigate cartilage breakdown and support joint function. In addition, this model-based framework emphasizes the interdependence between cartilage chronobiology and time-of-day-dependent responses to exercise, where strategically timed joint activity enhances nutrient and waste exchange, mitigates mitochondrial dysfunction, supports cellular metabolism, and promotes tissue maintenance, whereas nighttime rest promotes cartilage rehydration and repair. This time-sensitive, comprehensive approach aims to slow OA progression, reduce structural damage, and delay invasive procedures, particularly in weight-bearing joints such as the knee and hip. However, significant challenges remain, including inter-individual variability in circadian rhythms, a lack of reliable biomarkers for pharmacotherapeutic monitoring, and limited clinical evidence supporting chronoexercise protocols. Future large-scale, longitudinal trials are critical to evaluate the efficacy and scalability of this rational integrative strategy, paving the way for a new era in OA management.

Chondrocyte Ferritinophagy as a Molecular Mechanism of Arthritis-A Narrative Review

Osteoarthritis (OA) is a prevalent joint disease affecting orthopedic patients. Its incidence is steadily increasing, causing great economic hardship for individuals and society as a whole. OA is connected with risk factors such as genetics, obesity, and joint diseases; yet, its pathophysiology is still largely understood. At present, several cell death pathways govern the initiation and advancement of OA. It has been discovered that the onset and progression of OA are strongly associated with pyroptosis, senescence, apoptosis, ferroptosis, and autophagy. Ferroptosis and autophagy have not been well studied in OA, and elucidating their molecular mechanisms in chondrocytes is important for the diagnosis of OA. For this reason, we aim was reviewed recent national and international developments and provided an initial understanding of the molecular pathways underlying autophagy and ferroptosis in OA. We determined the reference period to be the last five years by searching for the keywords "osteoarthritis, mechanical stress, Pizeo1, ferroptosis, autophagy, ferritin autophagy" in the three databases of PUBMED, Web of Science, Google Scholar. We then screened irrelevant literature by reading the abstracts. Ferroptosis is a type of programmed cell death that is dependent on reactive oxygen species and Fe2+. It is primarily caused by processes linked to amino acid metabolism, lipid peroxidation, and iron metabolism. Furthermore, Piezoelectric mechanically sensitive ion channel assembly 1 (PIEZO1), which is triggered by mechanical stress, has been revealed to be intimately associated with ferroptosis events. It was found that mechanical injury triggers changes in the intracellular environment of articular chondrocytes (e.g., elevated levels of oxidative stress and increased inflammation) through PIEZO1, ultimately leading to iron death in chondrocytes. Therefore, we believe that PIEZO1 is a key initiator protein of iron death in chondrocytes. Widely present in eukaryotic cells, autophagy is a lysosome-dependent, evolutionarily conserved catabolic process that carries misfolded proteins, damaged organelles, and other macromolecules to lysosomes for breakdown and recycling. Throughout OA, autophagy is activated to differing degrees, indicating that autophagy may play a role in the development of OA. According to recent research, autophagy is a major factor in the process that leads cells to ferroptosis. Despite the notion of ferritinophagy being put forth, not much research has been done to clarify the connection between ferroptosis and autophagy in OA.

Molecular roles in membrane receptor signaling pathways and cascade reactions in chondrocytes: a review

Articular cartilage (AC) is a specialized connective tissue with unique biological and mechanical properties, which depends on the biological effects of each resident chondrocyte and its surrounding extracellular matrix (ECM) to form a unit that operates in a constant and balanced feedback loop. The surface membrane receptors of chondrocytes play a crucial role in the feedback balance of this biological unit. Various biological signals outside chondrocytes, such as water-soluble chemical signal molecules and mechanical signals, are unable to directly enter the cell and must first bind to the plasma membrane receptors to induce changes in the level and activity of intracellular signal transduction molecules. These changes then transmit through signaling cascade pathways into the nucleus, changing the cell phenotype, and producing physiological or pathological changes. Specific chemical and mechanical signals break the feedback balance of cartilage tissue units through membrane receptors. In the ECM environment, the molecular actions of chondrocyte membrane receptors in response to these specific signals, along with associated ion channel receptors, collectively regulate the biological effects of chondrocytes. This leads to decreased chondrocyte survival and an imbalance in ECM regulation, ultimately disrupting the tissue's molecular framework and physiological feedback mechanisms, and resulting in pathological changes in cartilage tissue. To provide insights into addressing the complexities associated with cartilage tissue injury and repair engineering, this review provides a comprehensive overview of the molecular mechanisms and biological implications of chondrocyte membrane receptor-mediated signal transduction, including G protein-coupled receptors (GPCRs), enzyme-linked receptors (tyrosine kinase receptors (TKRs)), and integrin receptors.

Clinical research progress of umbilical cord blood mesenchymal stem cells in Knee articular cartilage repair: A review

Umbilical cord blood mesenchymal stem cells (UCB-MSCs) are a type of adult stem cell with multipotent differentiation potential and immunoregulatory functions, primarily found in neonatal cord blood. Due to their noninvasive collection method, abundance, and ease of preservation, UCB-MSCs represent a promising biological material. This review examines the clinical research on UCB-MSCs in knee articular cartilage repair, highlighting their regenerative potential for treating knee joint cartilage defects. Our aim is to provide insights into current applications and propose directions for future research, focusing on optimizing clinical use and enhancing patient outcomes.

1,25(OH)2D3 induces chondrocyte autophagy and reduces the loss of proteoglycans in osteoarthritis through inhibiting the NF-κB pathway

OBJECTIVE

Nuclear transcription factor-κB (NF-κB) activation is a pivotal event in the pathogenesis of osteoarthritis (OA). OA patients frequently exhibit vitamin D (VD) deficiency, which is commonly associated with NF-κB activation. Our study aimed to investigate whether VD could protect against OA by modulating NF-κB pathway and to explore the underlying mechanisms.

METHODS

Proteins levels were assessed by western blot analysis, gene expression was quantified by quantitative real-time polymerase chain reaction (qRT‒PCR) in vivo and in vitro. The expression of phosphorylated-p65 (p-p65) in knee OA rats was detected by immunohistochemistry, and an NF-κB nuclear translocation assay was validated in chondrocytes. Immunoprecipitation was employed to detect the interaction between NF-κB and vitamin D receptor (VDR) in vivo and in vitro. Small interfering RNA (Si-NF-κB and Si-VDR) transfection was used to investigate the role of NF-κB and VDR signaling pathway in knee OA rats under VD influence. Cartilage changes were visualized of knee OA rats using hematoxylin and eosin as well as safranin-O/fast green of staining.

RESULTS

Our findings indicated that VD alleviates OA by inhibiting NF-κB pathway, which in turn reduces chondrocyte apoptosis and extracellular matrix (ECM) degradation. Further analysis revealed that VD primarily stabilizes NF-κB through the interaction of VDR and NF-κB, modulating the AMPK/mTOR signaling pathway to enhance autophagy and delay the progression of OA.

CONCLUSION

This study highlights the protective role of VD in OA by stabilization of NF-κB, mainly through the interaction between VDR and NF-κB. This interaction regulates the AMPK/mTOR signaling pathway, promoting autophagy and suggesting a potential therapeutic strategy for OA management. Key Points • VD confers a protective effect on OA by primarily stabilizing NF-κB through the interaction between VDR and NF-κB, which in turn inhibits NF-κB phosphorylation and nuclear translocation. • In chondrocytes, VD helps shield against OA by blocking NF-κB's entry into the nucleus, subsequently regulating autophagy via the AMPK/mTOR signaling pathway.

Advancements in hydrogel design for articular cartilage regeneration: A comprehensive review

This review paper explores the cutting-edge advancements in hydrogel design for articular cartilage regeneration (CR). Articular cartilage (AC) defects are a common occurrence worldwide that can lead to joint breakdown at a later stage of the disease, necessitating immediate intervention to prevent progressive degeneration of cartilage. Decades of research into the biomedical applications of hydrogels have revealed their tremendous potential, particularly in soft tissue engineering, including CR. Hydrogels are highly tunable and can be designed to meet the key criteria needed for a template in CR. This paper aims to identify those criteria, including the hydrogel components, mechanical properties, biodegradability, structural design, and integration capability with the adjacent native tissue and delves into the benefits that CR can obtain through appropriate design. Stratified-structural hydrogels that emulate the native cartilage structure, as well as the impact of environmental stimuli on the regeneration outcome, have also been discussed. By examining recent advances and emerging techniques, this paper offers valuable insights into developing effective hydrogel-based therapies for AC repair.

Decoding ferroptosis: transforming orthopedic disease management

As a mechanism of cell death, ferroptosis has gained popularity since 2012. The process is distinguished by iron toxicity and phospholipid accumulation, in contrast to autophagy, apoptosis, and other cell death mechanisms. It is implicated in the advancement of multiple diseases across the body. Researchers currently know that osteosarcoma, osteoporosis, and other orthopedic disorders are caused by NRF2, GPX4, and other ferroptosis star proteins. The effective relief of osteoarthritis symptoms from deterioration has been confirmed by clinical treatment with multiple ferroptosis inhibitors. At the same time, it should be reminded that the mechanisms involved in ferroptosis that regulate orthopedic diseases are not currently understood. In this manuscript, we present the discovery process of ferroptosis, the mechanisms involved in ferroptosis, and the role of ferroptosis in a variety of orthopedic diseases. We expect that this manuscript can provide a new perspective on clinical diagnosis and treatment of related diseases.

The matrix stiffness is increased in the eutopic endometrium of adenomyosis patients: a study based on atomic force microscopy and histochemistry

Previous ultrasound studies suggest that patients with adenomyosis (AM) exhibit increased uterine cavity stiffness, although direct evidence regarding extracellular matrix (ECM) content and its specific impact on endometrial stiffness remains limited. This study utilized atomic force microscopy to directly measure endometrial stiffness and collagen morphology, enabling a detailed analysis of the endometrium's mechanical properties: through this approach, we established direct evidence of increased endometrial stiffness and fibrosis in patients with AM. Endometrial specimens were also stained with Picrosirius red or Masson's trichrome to quantify fibrosis, and additional analyses assessed α-SMA and Ki-67 expression. Studies indicate that pathological conditions significantly influence the mechanical properties of endometrial tissue. Specifically, adenomyotic endometrial tissue demonstrates increased stiffness, associated with elevated ECM and fibrosis content, whereas normal endometrial samples are softer with lower ECM content. AM appears to alter both the mechanical and histological characteristics of the eutopic endometrium. Higher ECM content may significantly impact endometrial mechanical properties, potentially contributing to AM-associated decidualization defects and fertility challenges.

Identification of ZNF652 as a Diagnostic and Therapeutic Target in Osteoarthritis Using Machine Learning

Purpose

Osteoarthritis (OA) is the most common degenerative joint disease. However, its etiology remains largely unknown. Zinc Finger Protein 652 (ZNF652) is a transcription factor implicated in various biological processes. Nevertheless, its role in OA has not been elucidated.

Methods

The search term "osteoarthritis" was utilized to procure transcriptome data relating to OA patients and healthy people from the Gene Expression Omnibus (GEO) database. Then a screening process was initiated to identify differentially expressed genes (DEGs). The DEGs were discerned using three distinct machine learning methods. The accuracy of these DEGs in diagnosing OA was evaluated using the Receiver Operating Characteristic (ROC) Curve. A competitive endogenous RNA (ceRNA) visualization network was established to delve into potential regulatory targets. The ZNF652 expression was confirmed in the cartilage of OA rats using quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blotting (WB) and analyzed using an independent t-test.

Results

ZNF652 was identified as a DEG and exhibited the highest diagnostic value for OA according to the ROC analysis. The GO and KEGG enrichment analyses suggest that ZNF652 plays a vital role in OA development through processes including nitric oxide anabolism, macrophage proliferation, immune response, and the PI3K/Akt and the MAPK signaling pathways. The increased expression of ZNF652 in OA was validated in qRT-PCR (1.193 ± 0.005 vs 1.000 ± 0.005, p < 0.001) and WB (0.981 ± 0.055 vs 0.856 ± 0.026, p = 0.012) analysis.

Conclusion

ZNF652 was found to be related to OA pathogenesis and can potentially serve as a diagnostic and therapeutic target of OA. The underlying mechanism is that ZNF652 was related to nitric oxide anabolism, macrophage proliferation, various signaling pathways, and immune cells and their functions in OA. Nevertheless, the findings need to be confirmed in clinical trials and the molecular mechanism requires further study.

Construction of ferroptosis-related gene signatures for identifying potential biomarkers and immune cell infiltration in osteoarthritis

Osteoarthritis (OA) is a comprehensive joint disorder. The specific genes that trigger OA and the strategies for its effective management are not fully understood. This study focuses on identifying key genes linked to iron metabolism that could influence both the diagnosis and therapeutic approaches for OA. Analysis of GEO microarray data and iron metabolism genes identified 15 ferroptosis-related DEGs, enriched in hypoxia and HIF-1 pathways. Ten key hub genes (ATM, GCLC, PSEN1, CYBB, ATG7, MAP1LC3B, PLIN2, GRN, APOC1, SIAH2) were identified. Through stepwise regression, we screened 4 out of the above 10 genes, namely, GCLC, GRN, APOC1, and SIAH2, to obtain the optimal model. AUROCs for diagnosis of OA for the four hub genes were 0.81 and 0.80 of training and validation sets, separately. According to immune infiltration results, OA was related to significantly increased memory B cells, M0 macrophages, regulatory T cells, and resting mast cells but decreased activated dendritic cells. The four hub genes showed a close relation to them. It is anticipated that this model will aid in diagnosing osteoarthritis by assessing the expression of specific genes in blood samples. Moreover, studying these hub genes may further elucidate the pathogenesis of osteoarthritis.

From polarity to pathology: Decoding the role of cell orientation in osteoarthritis

Cell polarity refers to the orientation of tissue and organelles within a cell and the direction of its function. It is one of the most critical characteristics of metazoans. The development, growth, and functional tissue distribution are closely related to holistic tissue or organ homeostasis. However, the connection between cell polarity and osteoarthritis (OA) is less well-known. In OA, multiple chondrocyte clusters and tissue disorganisation can be observed in the degraded cartilage tissue. The excessive upregulation of the planar cell polarity (PCP) signalling pathway leads to the loss of cell polarity and organisation in OA progression and aetiology. Recent research has become increasingly aware of the importance of cell polarity and its correlation with OA. Several cell polarity-related treatments have shed light on OA. A thorough understanding of cell polarity and OA would provide more insights for future investigations to treat this worldwide disease.

THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE

Understanding cell polarity, associated signalling pathways, organelle changes, and cell movement in the development of OA could lead to advances in precision medicine and enhanced treatment strategies for OA patients.

The Therapeutic Potential of Exosomes vs. Matrix-Bound Nanovesicles from Human Umbilical Cord Mesenchymal Stromal Cells in Osteoarthritis Treatment

Osteoarthritis (OA) is a degenerative joint disease with limited therapeutic options, where inflammation plays a critical role in disease progression. Extracellular vesicles (EV) derived from mesenchymal stromal cells (MSC) have shown potential as a therapeutic approach for OA by modulating inflammation and alleviating degenerative processes in the joint. This study evaluated the therapeutic effects for the treatment of OA of two types of EV-exosomes and matrix-bound nanovesicles (MBV)-both derived from the human umbilical cord MSC (UC-MSC) via differential ultracentrifugation. Different phenotypes of human monocyte-derived macrophages (MDM) were used to study the anti-inflammatory properties of EV in vitro, and the medial meniscectomy-induced rat model of knee osteoarthritis (MMx) was used in vivo. The study found that both EV reduced pro-inflammatory cytokines IL-6 and TNF-α in MDM. However, exosomes showed superior results, preserving the extracellular matrix (ECM) of hyaline cartilage, and reducing synovitis more effectively than MBVs. Additionally, exosomes downregulated inflammatory markers (TNF-α, iNOS) and increased Arg-1 expression in macrophages and synovial fibroblasts, indicating a stronger anti-inflammatory effect. These results suggest UC-MSC exosomes as a promising therapeutic option for OA, with the potential for modulating inflammation and promoting joint tissue regeneration.

Advancing Cartilage Tissue Engineering: A Review of 3D Bioprinting Approaches and Bioink Properties

Articular cartilage is crucial in human physiology, and its degeneration poses a significant public health challenge. While recent advancements in 3D bioprinting and tissue engineering show promise for cartilage regeneration, there remains a gap between research findings and clinical application. This review critically examines the mechanical and biological properties of hyaline cartilage, along with current 3D manufacturing methods and analysis techniques. Moreover, we provide a quantitative synthesis of bioink properties used in cartilage tissue engineering. After screening 181 initial works, 33 studies using extrusion bioprinting were analyzed and synthesized, presenting results that indicate the main materials, cells, and methods utilized for mechanical and biological evaluation. Altogether, this review motivates the standardization of mechanical analyses and biomaterial assessments of 3D bioprinted constructs to clarify their chondrogenic potential.

Matrix Viscoelasticity Tunes the Mechanobiological Behavior of Chondrocytes

In articular cartilage, the pericellular matrix acting as a specialized mechanical microenvironment modulates environmental signals to chondrocytes through mechanotransduction. Matrix viscoelastic alterations during cartilage development and osteoarthritis (OA) degeneration play an important role in regulating chondrocyte fate and cartilage matrix homeostasis. In recent years, scientists are gradually realizing the importance of matrix viscoelasticity in regulating chondrocyte function and phenotype. Notably, this is an emerging field, and this review summarizes the existing literatures to the best of our knowledge. This review provides an overview of the viscoelastic properties of hydrogels and the role of matrix viscoelasticity in directing chondrocyte behavior. In this review, we elaborated the mechanotransuction mechanisms by which cells sense and respond to the viscoelastic environment and also discussed the underlying signaling pathways. Moreover, emerging insights into the role of matrix viscoelasticity in regulating chondrocyte function and cartilage formation shed light into designing cell-instructive biomaterial. We also describe the potential use of viscoelastic biomaterials in cartilage tissue engineering and regenerative medicine. Future perspectives on mechanobiological comprehension of the viscoelastic behaviors involved in tissue homeostasis, cellular responses, and biomaterial design are highlighted. Finally, this review also highlights recent strategies utilizing viscoelastic hydrogels for designing cartilage-on-a-chip.

Mesenchymal Stem Cell-Derived Exosomes as a Treatment Option for Osteoarthritis

Osteoarthritis (OA) is a leading cause of pain and disability worldwide in elderly people. There is a critical need to develop novel therapeutic strategies that can effectively manage pain and disability to improve the quality of life for older people. Mesenchymal stem cells (MSCs) have emerged as a promising cell-based therapy for age-related disorders due to their multilineage differentiation and strong paracrine effects. Notably, MSC-derived exosomes (MSC-Exos) have gained significant attention because they can recapitulate MSCs into therapeutic benefits without causing any associated risks compared with direct cell transplantation. These exosomes help in the transport of bioactive molecules such as proteins, lipids, and nucleic acids, which can influence various cellular processes related to tissue repair, regeneration, and immune regulation. In this review, we have provided an overview of MSC-Exos as a considerable treatment option for osteoarthritis. This review will go over the underlying mechanisms by which MSC-Exos may alleviate the pathological hallmarks of OA, such as cartilage degradation, synovial inflammation, and subchondral bone changes. Furthermore, we have summarized the current preclinical evidence and highlighted promising results from in vitro and in vivo studies, as well as progress in clinical trials using MSC-Exos to treat OA.

Bioinformatics proved the existence of potential hub genes activating autophagy to participate in cartilage degeneration in osteonecrosis of the femoral head

The obvious degeneration of articular cartilage occurs in the late stage of osteonecrosis of the femoral head (ONFH), which aggravates the condition of ONFH. This study aimed to demonstrate aberrant activation of autophagy processes in ONFH chondrocytes through bioinformatics and to predict and identify relevant hub genes and pathways. Differentially expressed genes (DEGs) were identified using R software in the GSE74089 dataset from the GEO database. DEGs were crossed with the Human Autophagy Database (HADb) autophagy genes to screen out autophagy-related differential genes (AT-DEGs). GSEA, GSVA, GO, and KEGG pathway enrichment analyses of AT-DEGs were performed. The STRING database was used to analyze the protein-protein interaction (PPI) of the AT-DEGs network, and the MCODE and CytoHubba plugin in the Cytoscape software was used to analyze the key gene cluster module and screen the hub genes. The PPI network of hub genes was constructed using the GeneMANIA database, and functional enrichment and gene connectivity categories were analyzed. The expression levels of hub genes of related genes in the ONFH patients were verified in the dataset GSE123568, and the protein expression was verified by immunohistochemistry in tissues. The analysis of DEGs revealed abnormal autophagy in ONFH cartilage. AT-DEGs in ONFH have special enrichment in macroautophagy, autophagosome membrane, and phosphatidylinositol-3-phosphate binding. In the GSE123568 dataset, it was also found that ATG2B, ATG4B, and UVRAG were all significantly upregulated in ONFH patients. By immunohistochemistry, it was verified that ATG2B, ATG4B, and UVRAG were significantly overexpressed. These three genes regulate the occurrence and extension of autophagosomes through the PI3KC3C pathway. Finally, we determined that chondrocytes in ONFH undergo positive regulation of autophagy through the corresponding pathways involved in three genes: ATG2B, ATG4B, and UVRAG.

Excessive mechanical loading promotes osteoarthritis development by upregulating Rcn2

Exposure of articular cartilage to excessive mechanical loading is closely related to the pathogenesis of osteoarthritis (OA). However, the exact molecular mechanism by which excessive mechanical loading drives OA remains unclear. In vitro, primary chondrocytes were exposed to cyclic tensile strain at 0.5 Hz and 10 % elongation for 30 min to simulate excessive mechanical loading in OA. In vivo experiments involved mice undergoing anterior cruciate ligament transection (ACLT) to model OA, followed by interventions on Rcn2 expression through adeno-associated virus (AAV) injection and tamoxifen-induced gene deletion. 10 μL AAV2/5 containing AAV-Rcn2 or AAV-shRcn2 was administered to the mice by articular injection at 1 week post ACLT surgery, and Col2a1-creERT: Rcn2flox/flox mice were injected with tamoxifen intraperitoneally to obtain Rcn2-conditional knockout mice. Finally, we explored the mechanism of Rcn2 affecting OA. Here, we identified reticulocalbin-2 (Rcn2) as a mechanosensitive factor in chondrocytes, which was significantly elevated in chondrocytes under mechanical overloading. PIEZO type mechanosensitive ion channel component 1 (Piezo1) is a critical mechanosensitive ion channel, which mediates the effect of mechanical loading on chondrocytes, and we found that increased Rcn2 could be suppressed through knocking down Piezo1 under excessive mechanical loading. Furthermore, chondrocyte-specific deletion of Rcn2 in adult mice alleviated OA progression in the mice receiving the surgery of ACLT. On the contrary, articular injection of Rcn2-expressing adeno-associated virus (AAV) accelerated the progression of ACLT-induced OA in mice. Mechanistically, Rcn2 accelerated the progression of OA through promoting the phosphorylation and nuclear translocation of signal transducer and activator of transcription 3 (Stat3).

Induced pluripotent stem cells in cartilage tissue engineering: a literature review

Osteoarthritis (OA) is a long-term, persistent joint disorder characterized by bone and cartilage degradation, resulting in tightness, pain, and restricted movement. Current attempts in cartilage regeneration are cell-based therapies using stem cells. Multipotent stem cells, such as mesenchymal stem cells (MSCs), and pluripotent stem cells, such as embryonic stem cells (ESCs), have been used to regenerate cartilage. However, since the discovery of human-induced pluripotent stem cells (hiPSCs) in 2007, it was seen as a potential source for regenerative chondrogenic therapy as it overcomes the ethical issues surrounding the use of ESCs and the immunological and differentiation limitations of MSCs. This literature review focuses on chondrogenic differentiation and 3D bioprinting technologies using hiPSCS, suggesting them as a viable source for successful tissue engineering.

METHODS

A literature search was conducted using scientific search engines, PubMed, MEDLINE, and Google Scholar databases with the terms 'Cartilage tissue engineering' and 'stem cells' to retrieve published literature on chondrogenic differentiation and tissue engineering using MSCs, ESCs, and hiPSCs.

RESULTS

hiPSCs may provide an effective and autologous treatment for focal chondral lesions, though further research is needed to explore the potential of such technologies.

CONCLUSIONS

This review has provided a comprehensive overview of these technologies and the potential applications for hiPSCs in regenerative medicine.

Revolutionizing osteoarthritis treatment: How mesenchymal stem cells hold the key

Osteoarthritis (OA) is a multifaceted disease characterized by imbalances in extracellular matrix metabolism, chondrocyte and synoviocyte senescence, as well as inflammatory responses mediated by macrophages. Although there have been notable advancements in pharmacological and surgical interventions, achieving complete remission of OA remains a formidable challenge, oftentimes accompanied by significant side effects. Mesenchymal stem cells (MSCs) have emerged as a promising avenue for OA treatment, given their ability to differentiate into chondrocytes and facilitate cartilage repair, thereby mitigating the impact of an inflammatory microenvironment induced by macrophages. This comprehensive review aims to provide a concise overview of the diverse roles played by MSCs in the treatment of OA, while elucidating the underlying mechanisms behind these contributions. Specifically, the roles include: (a) Promotion of chondrocyte and synoviocyte regeneration; (b) Inhibition of extracellular matrix degradation; (c) Attenuating the macrophage-induced inflammatory microenvironment; (d) Alleviation of pain. Understanding the multifaceted roles played by MSCs in OA treatment is paramount for developing novel therapeutic strategies. By harnessing the regenerative potential and immunomodulatory properties of MSCs, it may be possible to devise more effective and safer approaches for managing OA. Further research and clinical studies are warranted to optimize the utilization of MSCs and realize their full potential in the field of OA therapeutics.

The role of targeting glucose metabolism in chondrocytes in the pathogenesis and therapeutic mechanisms of osteoarthritis: a narrative review

Osteoarthritis (OA) is a common degenerative joint disease that can affect almost any joint, mainly resulting in joint dysfunction and pain. Worldwide, OA affects more than 240 million people and is one of the leading causes of activity limitation in adults. However, the pathogenesis of OA remains elusive, resulting in the lack of well-established clinical treatment strategies. Recently, energy metabolism alterations have provided new insights into the pathogenesis of OA. Accumulating evidence indicates that glucose metabolism plays a key role in maintaining cartilage homeostasis. Disorders of glucose metabolism can lead to chondrocyte hypertrophy and extracellular matrix degradation, and promote the occurrence and development of OA. This article systematically summarizes the regulatory effects of different enzymes and factors related to glucose metabolism in OA, as well as the mechanism and potential of various substances in the treatment of OA by affecting glucose metabolism. This provides a theoretical basis for a better understanding of the mechanism of OA progression and the development of optimal prevention and treatment strategies.

LncRNA-mediated cartilage homeostasis in osteoarthritis: a narrative review

Osteoarthritis (OA) is a degenerative disease of cartilage that affects the quality of life and has increased in morbidity and mortality in recent years. Cartilage homeostasis and dysregulation are thought to be important mechanisms involved in the development of OA. Many studies suggest that lncRNAs are involved in cartilage homeostasis in OA and that lncRNAs can be used to diagnose or treat OA. Among the existing therapeutic regimens, lncRNAs are involved in drug-and nondrug-mediated therapeutic mechanisms and are expected to improve the mechanism of adverse effects or drug resistance. Moreover, targeted lncRNA therapy may also prevent or treat OA. The purpose of this review is to summarize the links between lncRNAs and cartilage homeostasis in OA. In addition, we review the potential applications of lncRNAs at multiple levels of adjuvant and targeted therapies. This review highlights that targeting lncRNAs may be a novel therapeutic strategy for improving and modulating cartilage homeostasis in OA patients.

Association between niacin intake and knee osteoarthritis pain and function: a longitudinal cohort study

BACKGROUND

This research investigates the relationship between niacin intake and knee osteoarthritis (OA) severity, focusing on pain and functional ability due to niacin's role as a NAD(P)+ precursor, promoting cellular energy, and offering anti-inflammatory, analgesic, and antioxidant effects.

METHODS

The population-based Osteoarthritis Initiative (OAI) cohort with radiographically confirmed knee OA was analyzed through a Food Frequency Questionnaire determining niacin intake and scores from the Knee Injury and Osteoarthritis Outcome Score (KOOS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), using generalized additive mixed models.

RESULTS

A significant correlation was pinpointed in 2375 OA patients (1001 men and 1374 women; 55.96% aged between 45 and 65 and 44.04% aged ≥65) between niacin intake and reduced knee pain and functional degrees after a 48-month follow-up, evident in improved KOOS and WOMAC scores (P < 0.05). The fully adjusted models estimated a decrease of 0.26 points for every additional 1 unit of Ln-niacin intake of daily niacin intake on the WOMAC pain subscale, 0.83 points on the WOMAC function subscale, and an increase of 1.71 and 1.58 on the KOOS pain and quality of life score. Strikingly, subgroups including middle-aged individuals, women, white race, obese individuals, and those with specific dietary habits showed a more substantial improvement with increased niacin.

CONCLUSION

The association between increased niacin intake and reduced pain and function scores, as well improved quality of life in knee OA patients, is significant. Certain cohorts, according to a stratified analysis, could see more considerable benefits with increased niacin consumption.

HIGHLIGHTS

• Increased niacin intake is linked to reduced knee pain and better function in OA patients. • Specific subgroups, such as middle-aged individuals, women, and those with certain dietary habits, benefit more from increased niacin consumption. • Niacin shows promise for enhancing the quality of life in knee OA patients by reducing pain and improving function.

Does Walking Have an Association with Osteoarthritis? A Two-Sample Mendelian Randomization Analysis

Objective

Osteoarthritis (OA) is one of the major disabling human diseases. The related studies indicate a potential correlation between walking and OA. However, there is still a lack of evidence in genetics to support the correlation between walking and OA. Therefore, this study aimed to explore the relationship between walking and OA at the genetic level.

Methods

The publicly available Genome Wide Association Study (GWAS) data were used, with inverse variance weighting (IVW, the random-effects model) as the main analysis method, whereas MR-Egger, Weighted median, Simple mode, and Weighted mode as the secondary analysis methods. In addition, Cochran's Q test, pleiotropy test, and MR-Egger intercept test were conducted to examine the heterogeneity and pleiotropy of the outcome.

Results

In the MR analysis, IVW results showed a negative correlation between types of physical activity in last 4 weeks: Walking for pleasure (not as a means of transport) and OA (KOA or HOA) (odds ratio (OR) = 0.3224, 95% confidence interval (CI): 0.1261 to 0.8243), and the difference was of statistical significance (P = 0.0181). Moreover, IVW results also revealed a negative correlation between types of physical activity in last 4 weeks: Walking for pleasure (not as a means of transport) and KOA (OR = 0.1396, 95% CI: 0.0484 to 0.4026), and the difference was statistically significant (P = 0.0003). However, IVW results did not demonstrate any statistical significance types of physical activity in last 4 weeks: Walking for pleasure (not as a means of transport) and HOA (OR = 1.2075, 95% CI: 0.1978 to 7.3727, P = 0.8381).

Conclusion

From genetic studies, types of physical activity in last 4 weeks: Walking for pleasure (not as a means of transport) is negatively correlated with knee osteoarthritis (KOA), but there is no clear evidence supporting its correlation with hip osteoarthritis (HOA).

Alteration in cartilage matrix stiffness as an indicator and modulator of osteoarthritis

Osteoarthritis (OA) is characterized by cartilage degeneration and destruction, leading to joint ankylosis and disability. The major challenge in diagnosing OA at early stage is not only lack of clinical symptoms but also the insufficient histological and immunohistochemical signs. Alteration in cartilage stiffness during OA progression, especially at OA initiation, has been confirmed by growing evidences. Moreover, the stiffness of cartilage extracellular matrix (ECM), pericellular matrix (PCM) and chondrocytes during OA development are dynamically changed in unique and distinct fashions, revealing possibly inconsistent conclusions when detecting cartilage matrix stiffness at different locations and scales. In addition, it will be discussed regarding the mechanisms through which OA-related cartilage degenerations exhibit stiffened or softened matrix, highlighting some critical events that generally incurred to cartilage stiffness alteration, as well as some typical molecules that participated in constituting the mechanical properties of cartilage. Finally, in vitro culturing chondrocytes in various stiffness-tunable scaffolds provided a reliable method to explore the matrix stiffness-dependent modulation of chondrocyte metabolism, which offers valuable information on optimizing implant scaffolds to maximally promote cartilage repair and regeneration during OA. Overall, this review systematically and comprehensively elucidated the current progresses in the relationship between cartilage stiffness alteration and OA progression. We hope that deeper attention and understanding in this researching field will not only develop more innovative methods in OA early detection and diagnose but also provide promising ideas in OA therapy and prognosis.

Effect of Traditional Chinese Non-Pharmacological Therapies on Knee Osteoarthritis: A Narrative Review of Clinical Application and Mechanism

Knee osteoarthritis (KOA) stands as a degenerative ailment with a substantial and escalating prevalence. The practice of traditional Chinese non-pharmacological therapy has become a prevalent complementary and adjunctive approach. A mounting body of evidence suggests its efficacy in addressing KOA. Recent investigations have delved into its underlying mechanism, yielding some headway. Consequently, this comprehensive analysis seeks to encapsulate the clinical application and molecular mechanism of traditional Chinese non-pharmacological therapy in KOA treatment. The review reveals that various therapies, such as acupuncture, electroacupuncture, warm needle acupuncture, tuina, and acupotomy, primarily target localized knee components like cartilage, subchondral bone, and synovium. Moreover, their impact extends to the central nervous system and intestinal flora. More perfect experimental design and more comprehensive research remain a promising avenue in the future.

Screening of Biomarkers Associated with Osteoarthritis Aging Genes and Immune Correlation Studies

Purpose

Osteoarthritis (OA) is a joint disease with a long and slow course, which is one of the major causes of disability in middle and old-aged people. This study was dedicated to excavating the cellular senescence-associated biomarkers of OA.

Methods

The Gene Expression Omnibus (GEO) database was searched and five datasets pertaining to OA were obtained. After removing the batch effect, the GSE55235, GSE55457, GSE82107, and GSE12021 datasets were integrated together for screening of the candidate genes by differential analysis and weighted gene co-expression network analysis (WGCNA). Next, those genes were further filtered by machine learning algorithms to obtain cellular senescence-associated biomarkers of OA. Subsequently, enrichment analyses based on those biomarkers were conducted, and we profiled the infiltration levels of 22 types immune cells with the ERSORT algorithm. A lncRNA-miRNA-mRNA regulatory and drug-gene network were constructed. Finally, we validated the senescence-associated biomarkers at both in vivo and in vitro levels.

Results

Five genes (BCL6, MCL1, SLC16A7, PIM1, and EPHA3) were authenticated as cellular senescence-associated biomarkers in OA. ROC curves demonstrated the reliable capacity of the five genes as a whole to discriminate OA samples from normal samples. The nomogram diagnostic model based on 5 genes proved to be a reliable predictor of OA. Single-gene GSEA results pointed to the involvement of the five biomarkers in immune-related pathways and oxidative phosphorylation in the development of OA. Immune infiltration analysis manifested that the five genes were significantly correlated with differential immune cells. Subsequently, a lncRNA-miRNA-mRNA network and gene-drug network containing were generated based on five cellular senescence-associated biomarkers in OA.

Conclusion

A foundation for understanding the pathophysiology of OA and new insights into OA diagnosis and treatment were provided by the identification of five genes, namely BCL6, MCL1, SLC16A7, PIM1, and EPHA3, as biomarkers associated with cellular senescence in OA.

Relationship of weight change patterns from young to middle adulthood with incident rheumatoid arthritis and osteoarthritis: a retrospective cohort study

Background

The relationship between weight change patterns and arthritis onset, specifically rheumatoid arthritis (RA) and osteoarthritis (OA), is unclear. We examined the association between weight changes from young adulthood to midlife and arthritis onset.

Methods

Using data from NHANES 1999-2018, participants with self-reported arthritis were selected. Age at diagnosis determined arthritis onset. Weight change patterns were based on BMI at age 25 and 10 years before the survey. Patterns were categorized as stable non-obese, non-obese to obese, obese to non-obese, and stable obese. Cox regression models and restricted cubic spline (RCS) analysis were employed, calculating hazard ratios (HRs) and 95% confidence intervals (CIs) considering covariates.

Results

Out of 20,859 participants (male 11,017, 52.82%), 4922 developed arthritis over a mean 8.66-year follow-up. Compared to stable non-obese individuals, the HRs for arthritis were 1.55 (95% CI=1.45 to 1.66, P < 0.0001) for non-obese to obese and 1.74 (95% CI=1.56 to 1.95, P < 0.0001) for stable obese. Those gaining 10-20 kg had a HR of 1.33 (95% CI=1.22 to 1.46, P < 0.0001), and gains >20 kg had a HR of 1.56 (95% CI=1.42 to 1.71, P < 0.0001), compared to stable weight (change within 2.5 kg). Identical results observed for OA and RA. RCS showed a nonlinear relationship between weight change and arthritis (all P < 0.01).

Conclusions

Stable obesity and weight gain during adulthood increase arthritis risk. Maintaining a non-obese weight throughout adult years might reduce arthritis risk in later life.

Long Non-coding RNA DLEU1 Promotes Progression of Osteoarthritis via miR-492/TLR8 Axis

BACKGROUND

Long non-coding RNAs (LncRNAs) are generally reported to participate in the development of Osteoarthritis (OA) by acting as competing endogenous RNAs (ceRNAs). However, the molecular mechanism is largely unknown. This study aimed to investigate the possible mechanisms contributing to osteoarthritis (OA).

METHODS

Four gene expression profiles from patients with OA were downloaded from a public database and integrated to screen important RNAs associated with OA. Differentially expressed (DE) lncRNAs, microRNAs (miRNAs), and mRNAs were filtered, and a ceRNA network was constructed. An in vitro OA model was established by treating chondrocytes with IL-1β. The expression levels of MMP-13, COL2A1, aggrecan, and RUNX2 were detected by qRT-PCR and western blot. Cell proliferation ability was detected by CCK-8 assay. Flow cytometry was used for apoptosis assay. A dual luciferase reporter gene was used to confirm the relationship between DLEU1, miR-492, and TLR8.

RESULTS

An OA-related ceRNA network, including 11 pathways, 3 miRNAs, 7 lncRNAs, and 16 mRNAs, was constructed. DLEU1 and TLR8 were upregulated, and miR-492 was downregulated in IL-1β-induced chondrocytes. Overexpression of DLEU1 suppressed viability and promoted apoptosis and extracellular matrix (ECM) degradation in IL-1β induced chondrocytes. Luciferase reporter assay validated the regulatory relations among DLEU1, miR-492, and TLR8. Further study revealed that the effects of DLEU1 on chondrocytes could be reversed by miR-492.

CONCLUSION

DLEU1 may be responsible for the viability, apoptosis, and ECM degradation in OA via miR-492/TLR8 axis.

Research progress in arthritis treatment with the active components of Herba siegesbeckiae

Arthritis is a group of diseases characterized by joint pain, swelling, stiffness, and limited movement. Osteoarthritis, rheumatoid arthritis, and gouty arthritis are the most common types of arthritis. Arthritis severely affects the quality of life of patients and imposes a heavy financial and medical burden on their families and society at large. As a widely used traditional Chinese medicine, Herba siegesbeckiae has many pharmacological effects such as anti-inflammatory and analgesic, anti-ischemic injury, cardiovascular protection, and hypoglycemic. In addition, it has significant therapeutic effects on arthritis. The rich chemical compositions of H. siegesbeckiae primarily include diterpenoids, sesquiterpenoids, and flavonoids. As one of the main active components of H. siegesbeckiae, kirenol and quercetin play a vital role in reducing arthritis symptoms. In the present study, the research progress in arthritis treatment with the active components of H. siegesbeckiae is reviewed.

Musculoskeletal Diseases: From Molecular Basis to Therapy

Musculoskeletal diseases (MSDs) comprise a plethora of different disorders (more than 150 conditions) affecting the locomotor system [...].

Tanshinone IIA Facilitates Efficient Cartilage Regeneration under Inflammatory Factors Caused Stress via Upregulating LncRNA NEAT1_2

(1) Background: Osteoarthritis (OA) is a crippling condition characterized by chondrocyte dedifferentiation, cartilage degradation, and subsequent cartilage defects. Unfortunately, there is a lack of effective medicines to facilitate the repair of cartilage defects in OA patients. In this study, we investigated the role of lncRNA NEAT1_2 in maintaining the chondrocyte phenotype and identified tanshinone IIA(TAN) as a natural medicine that enhances NEAT1_2 levels, resulting in efficient cartilage regeneration under inflammatory cytokines. (2) Methods: The transcriptional levels of NEAT1_2 and cartilage phenotype-related genes were identified by RT-qPCR. The siRNA interference approach was utilized to silence NEAT1_2; the Alamar Blue assay was performed to determine chondrocyte viability under inflammatory conditions. To evaluate the concentrations of collagen type II and glycosaminoglycans distributed by chondrocytes in vitro and in vivo, immunohistochemical staining and Safranin O staining were used. (3) Results: IL-1β suppresses NEAT1_2 and genes related to the chondrocytic phenotype, whereas TAN effectively upregulates them in a NEAT1_2-dependent manner. Consistently, TAN alleviated chondrocyte oxidative stress inhibited cartilage degradation by modulating the relevant genes and promoted efficient cartilage regeneration in vitro and in vivo when chondrocytes are exposed to inflammatory cytokines. (4) Conclusions: TAN enhances the expression of NEAT1_2 inhibited by IL-1β and affects the transcription of chondrocytic phenotype-related genes, which promotes cartilage regeneration in an inflammatory environment.

The effects of physiological and injurious hydrostatic pressure on murine ex vivo articular and growth plate cartilage explants: an RNAseq study

Introduction

Chondrocytes are continuously exposed to loads placed upon them. Physiological loads are pivotal to the maintenance of articular cartilage health, while abnormal loads contribute to pathological joint degradation. Similarly, the growth plate cartilage is subject to various loads during growth and development. Due to the high-water content of cartilage, hydrostatic pressure is considered one of the main biomechanical influencers on chondrocytes and has been shown to play an important role in the mechano-regulation of cartilage.

Methods

Herein, we conducted RNAseq analysis of ex vivo hip cap (articular), and metatarsal (growth plate) cartilage cultures subjected to physiological (5 MPa) and injurious (50 MPa) hydrostatic pressure, using the Illumina platform (n = 4 replicates).

Results

Several hundreds of genes were shown to be differentially modulated by hydrostatic pressure, with the majority of these changes evidenced in hip cap cartilage cultures (375 significantly upregulated and 322 downregulated in 5 MPa versus control; 1022 upregulated and 724 downregulated in 50 MPa versus control). Conversely, fewer genes were differentially affected by hydrostatic pressure in the metatarsal cultures (5 significantly upregulated and 23 downregulated in 5 MPa versus control; 7 significantly upregulated and 19 downregulated in 50 MPa versus control). Using Gene Ontology annotations for Biological Processes, in the hip cap data we identified a number of pathways that were modulated by both physiological and injurious hydrostatic pressure. Pathways upregulated in response to 50 MPa versus control, included those involved in the generation of precursor metabolites and cellular respiration. Biological processes that were downregulated in this tissue included ossification, connective tissue development, and chondrocyte differentiation.

Discussion

Collectively our data highlights the divergent chondrocyte phenotypes in articular and growth plate cartilage. Further, we show that the magnitude of hydrostatic pressure application has distinct effects on gene expression and biological processes in hip cap cartilage explants. Finally, we identified differential expression of a number of genes that have previously been identified as osteoarthritis risk genes, including Ctsk, and Chadl. Together these data may provide potential genetic targets for future investigations in osteoarthritis research and novel therapeutics.

Development of Anti-OSCAR Antibodies for the Treatment of Osteoarthritis

Osteoarthritis (OA) is the most common joint disease that causes local inflammation and pain, significantly reducing the quality of life and normal social activities of patients. Currently, there are no disease-modifying OA drugs (DMOADs) available, and treatment relies on pain relief agents or arthroplasty. To address this significant unmet medical need, we aimed to develop monoclonal antibodies that can block the osteoclast-associated receptor (OSCAR). Our recent study has revealed the importance of OSCAR in OA pathogenesis as a novel catabolic regulator that induces chondrocyte apoptosis and accelerates articular cartilage destruction. It was also shown that blocking OSCAR with a soluble OSCAR decoy receptor ameliorated OA in animal models. In this study, OSCAR-neutralizing monoclonal antibodies were isolated and optimized by phage display. These antibodies bind to and directly neutralize OSCAR, unlike the decoy receptor, which binds to the ubiquitously expressed collagen and may result in reduced efficacy or deleterious off-target effects. The DMOAD potential of the anti-OSCAR antibodies was assessed with in vitro cell-based assays and an in vivo OA model. The results demonstrated that the anti-OSCAR antibodies significantly reduced cartilage destruction and other OA signs, such as subchondral bone plate sclerosis and loss of hyaline cartilage. Hence, blocking OSCAR with a monoclonal antibody could be a promising treatment strategy for OA.

IL-17 in osteoarthritis: A narrative review

Osteoarthritis (OA) is a painful joint disease that is common among the middle-aged and elderly populations, with an increasing prevalence. Therapeutic options for OA are limited, and the pathogenic mechanism of OA remains unclear. The roles of cytokines and signaling pathways in the development of OA is a current research hot spot. Interleukin (IL)-17 is a pleiotropic inflammatory cytokine produced mainly by T helper 17 cells that has established roles in host defense, tissue repair, lymphoid tissue metabolism, tumor progression, and pathological processes of immune diseases, and studies in recent years have identified an important role for IL-17 in the progression of OA. This narrative review focuses on the mechanisms by which IL-17 contributes to articular cartilage degeneration and synovial inflammation in OA and discusses how IL-17 and the IL-17 signaling pathway affect the pathological process of OA. Additionally, therapeutic targets that have been proposed in recent years based on IL-17 and its pathway in OA are summarized as well as recent advances in the study of IL-17 pathway inhibitors and the potential challenges of their use for OA treatment.

Knee Cartilage Lesion Management-Current Trends in Clinical Practice

Many patients, particularly those aged above 40, experience knee joint pain, which hampers both sports activities and daily living. Treating isolated chondral and osteochondral defects in the knee poses a significant clinical challenge, particularly in younger patients who are not typically recommended partial or total knee arthroplasty as alternatives. Several surgical approaches have been developed to address focal cartilage defects. The treatment strategies are characterized as palliation (e.g., chondroplasty and debridement), repair (e.g., drilling and microfracture), or restoration (e.g., autologous chondrocyte implantation, osteochondral autograft, and osteochondral allograft). This review offers an overview of the commonly employed clinical methods for treating articular cartilage defects, with a specific focus on the clinical trials conducted in the last decade. Our study reveals that, currently, no single technology fully meets the essential requirements for effective cartilage healing while remaining easily applicable during surgical procedures. Nevertheless, numerous methods are available, and the choice of treatment should consider factors such as the location and size of the cartilage lesion, patient preferences, and whether it is chondral or osteochondral in nature. Promising directions for the future include tissue engineering, stem cell therapies, and the development of pre-formed scaffolds from hyaline cartilage, offering hope for improved outcomes.

Evaluation of Cartilage Integrity Following Administration of Oral and Intraarticular Nifedipine in a Murine Model of Osteoarthritis

Osteoarthritis (OA) ranks as the prevailing type of arthritis on a global scale, for which no effective treatments are currently available. Arterial hypertension is a common comorbidity in OA patients, and antihypertensive drugs, such as nifedipine (NIF), may affect the course of OA progression. The aim of this preclinical study was to determine the effect of nifedipine on healthy and OA cartilage, depending on its route of administration. In this study, we used the destabilization of medial meniscus to develop a mouse model of OA. Nifedipine was applied per os or intraarticularly (i.a.) for 8 weeks to both mice with OA and healthy animals. Serum biomarker concentrations were evaluated using the Luminex platform and alterations in the knee cartilage were graded according to OARSI histological scores and investigated immunohistochemically. Nifedipine treatment per os and i.a. exerted protective effects, as assessed by the OARSI histological scores. However, long-term nifedipine i.a. injections induced the deterioration of healthy cartilage. Lubricin, cartilage intermediate layer matrix protein (CILP), collagen type VI (COLVI), CILP, and Ki67 were upregulated by the nifedipine treatment. Serum biomarkers MMP-3, thrombospondin-4, and leptin were upregulated in the healthy groups treated with nifedipine, while only the levels of MMP-3 were significantly higher in the OA group treated with nifedipine per os compared to the untreated group. In conclusion, this study highlights the differential effects of nifedipine on cartilage integrity, depending on the route of administration and cartilage condition.