Surgical management of osteoarthritis

Osteoarthritis: Insights into Diagnosis, Pathophysiology, Therapeutic Avenues, and the Potential of Natural Extracts

Osteoarthritis (OA) stands as a prevalent and progressively debilitating clinical condition globally, impacting joint structures and leading to their gradual deterioration through inflammatory mechanisms. While both non-modifiable and modifiable factors contribute to its onset, numerous aspects of OA pathophysiology remain elusive despite considerable research strides. Presently, diagnosis heavily relies on clinician expertise and meticulous differential diagnosis to exclude other joint-affecting conditions. Therapeutic approaches for OA predominantly focus on patient education for self-management alongside tailored exercise regimens, often complemented by various pharmacological interventions primarily targeting pain alleviation. However, pharmacological treatments typically exhibit short-term efficacy and local and/or systemic side effects, with prosthetic surgery being the ultimate resolution in severe cases. Thus, exploring the potential integration or substitution of conventional drug therapies with natural compounds and extracts emerges as a promising frontier in enhancing OA management. These alternatives offer improved safety profiles and possess the potential to target specific dysregulated pathways implicated in OA pathogenesis, thereby presenting a holistic approach to address the condition's complexities.

LncRNA DNM3OS regulates GREM2 via miR-127-5p to suppress early chondrogenic differentiation of rat mesenchymal stem cells under hypoxic conditions

Background

Improved chondrogenic differentiation of mesenchymal stem cells (MSCs) by genetic regulation is a potential method for regenerating articular cartilage. MiR-127-5p has been reported to promote cartilage differentiation of rat bone marrow MSCs (rMSCs); however, the regulatory mechanisms underlying hypoxia-stimulated chondrogenic differentiation remain unknown.

Methods

rMSCs were induced to undergo chondrogenic differentiation under normoxic or hypoxic conditions. Expression of lncRNA DNM3OS, miR-127-5p, and GREM2 was detected by quantitative real-time PCR. Proteoglycans were detected by Alcian blue staining. Western blot assays were performed to examine the relative levels of GREM2 and chondrogenic differentiation related proteins. Luciferase reporter assays were performed to assess the association among DNM3OS, miR-127-5p, and GREM2.

Results

MiR-127-5p levels were upregulated, while DNM3OS and GREM2 levels were downregulated in rMSCs induced to undergo chondrogenic differentiation, and those changes were attenuated by hypoxic conditions (1% O₂). Further in vitro experiments revealed that downregulation of miR-127-5p reduced the production of proteoglycans and expression of chondrogenic differentiation markers (COL1A1, COL2A1, SOX9, and ACAN) and osteo/chondrogenic markers (BMP-2, p-SMAD1/2). MiR-127-5p overexpression produced the opposite results in rMSCs induced to undergo chondrogenic differentiation under hypoxic conditions. GREM2 was found to be a direct target of miR-127-5p, which was suppressed in rMSCs undergoing chondrogenic differentiation. Moreover, DNM3OS could directly bind to miR-127-5p and inhibit chondrogenic differentiation of rMSCs via regulating GREM2.

Conclusions

Our study revealed a novel molecular pathway (DNM3OS/miR-127-5p/GREM2) that may be involved in hypoxic chondrogenic differentiation.

miR-134 inhibits chondrogenic differentiation of bone marrow mesenchymal stem cells by targetting SMAD6

Various miRNAs have been reported to regulate the chondrogenic differentiation of bone marrow mesenchymal stem cells (BMSCs); however, whether miR-134 plays a role in this biological process remains undetermined. In the present study, we first evaluated the chondrogenic differentiation of BMSCs by Alcian blue staining, and examined the miR-134 expression by quantitative real-time PCR (qRT-PCR) during this process. And miR-134 inhibitor was used to investigate the functions of miR-134 in chondrogenic differentiation of BMSCs by Alcian blue staining, qRT-PCR, and Western blot. Subsequently, the correlation between miR-134 and SMAD6 was assessed via bioinformatics analysis and dual-luciferase reporter assay. Finally, the role of SMAD6 in chondrogenic differentiation of BMSCs was also determined through Alcian blue staining, qRT-PCR, and Western blot. As results showed that miR-134 expression was significantly down-regulated during chondrogenic differentiation, and inhibition of miR-134 obviously promoted chondrogenic differentiation. Dual-luciferase reporter assay indicated that miR-134 could directly target the 3′-UTRs of SMAD6, inhibit miR-134 expression in BMSCs, and up-regulate SMAD6 expression. Moreover, we found that overexpression of SMAD6 significantly promoted chondrogenic differentiation, and that SMAD6-induced promotion of chondrogenic differentiation could be reversed by miR-134 mimics. In conclusion, our findings suggest that miR-134 may act as a negative regulator during chondrogenic differentiation of BMSCs by interacting with SMAD6.

Effects of working gas pressure on zirconium dioxide thin film prepared by pulsed plasma deposition: roughness, wettability, friction and wear characteristics

In joint arthroplasty one of the main issues related to the failure of prosthetic implants is due to the wear of the ultra-high molecular weight polyethylene (UHMWPE) component. Surface treatments and coatings have been recognized as enhancing methods, able to improve the tribological properties of the implants. Therefore, the main objective of this work was to investigate the possibility to fabricate yttria-stabilized zirconia (YSZ) coatings on a metal (AISI 316-L) substrate by means of Pulsed Electron Deposition, in order to improve the tribological behavior of the polymer-metal coupling, by reducing the initial wear of the UHMWPE component. In order to optimize the coating characteristics, the effects of working gas pressure on both its morphological and tribological properties were analyzed. Morphological characterization of the films was evaluated by Atomic Force Microscopy (AFM). Coating wettability was also estimated by contact angle (CA) measurement. Tribological performance (coupling friction and wear of UHMWPE) was evaluated by using a ball-on-disc tribometer during highly-stressing tests in dry and lubricated (i.e. NaCl and serum) conditions; friction and wear were specifically evaluated at the initial sliding distances - to highlight the main effect of coating morphology - and after 100m - where the influence of the intrinsic materials properties prevails. AFM analysis highlighted that the working pressure heavily affected the morphological characteristics of the realized films. The wettability of the coating at the highest and lowest deposition pressures (CA ~ 60°, closed to substrate value) decreased for intermediate pressures, reaching a maximum CA of ~ 90°. Regarding tribological tests, a strong correlation was found in the initial steps between friction coefficient and wettability, which decreased as the distance increased. Concerning UHMWPE wear associated to coated counterpart, at 100m a reduction rate of about 7% in dry, 12% in NaCl and 5% in presence of serum was obtained compared to the uncoated counterpart. Differently from what highlighted for friction, no correlation was found between wear rate and morphological parameters. These findings, in agreement with literature, underlined the effect of the deposition pressure on the morphological properties, but suggested that physical characteristics are influenced too. Further research on the deposition process will be required in order to improve the tribological performance of the coating at long distances, addressing - above all - orthopedic applications.

An overview of hydrogel-based intra-articular drug delivery for the treatment of osteoarthritis

Drug administration by intra-articular injection is an emerging popular treatment for knee osteoarthritis (OA). This method of drug administration minimizes the toxic effects of the drugs administered systemically, and maximizes local effects. However, traditional oral drugs delivered via intra-articular injection are limited by the lack of sustained release. Injectable materials such as hydrogels or hydrogel microspheres have been extensively studied for their applications as intra-articular injection for the treatment of OA, which is attribute to their minimally invasive manner, extended drug retention time and high loading efficiency. In this review, we summarized hydrogel types and hydrogel characteristics for intra-articular injection, and the drugs, proteins and cells used in the injectable delivery systems. Through this review, we hope to inspire researchers to construct novel hydrogel-based delivery system for the intra-articular injection treatment of knee OA.

How does surgery compare with advanced intra-articular therapies in knee osteoarthritis: current thoughts

The objectives of osteoarthritis (OA) management are to reduce pain and inflammation, slow cartilage degradation, improve function and reduce disability. Current strategies for managing knee OA include nonpharmacological interventions, oral pharmacological treatments, localized intra-articular injections, and surgery. It has become evident that the inflammatory response is a key contributor to the development and progression of knee OA. Signaling pathways involving growth factors and cytokines are being investigated for the development of new therapies that target the underlying biological processes causing the disease. This concept of 'molecular orthopedics' enables more patient-centered diagnostic and treatment strategies. In contrast to other conservative therapies, which ultimately only address OA symptoms, intra-articular injections, in particular autologous conditioned serum (ACS), provide benefits that have the potential to outweigh those of established pharmacological treatments and surgery. Surgery has historically been considered the final solution for treatment of knee OA, both by treating physicians and by patients; however, there are increasing concerns regarding the lack of randomized clinical trials providing evidence to support this opinion. Intra-articular injection of ACS has demonstrated efficacy as a treatment for knee OA in a number of studies, with a very low rate of adverse events and side effects, compared with surgery. Treatment with ACS utilizes the release of anti-inflammatory cytokines and regenerative growth factors to support the natural healing processes in the knee, and has the potential to provide a valuable alternative to surgical intervention.