Hyaluronic Acid: Molecular Mechanisms and Therapeutic Trajectory

Hyaluronic acid ameliorates intervertebral disc degeneration via promoting mitophagy activation

Activation of mitophagy was considered to be a potential therapeutic strategy for intervertebral disc degeneration (IDD). There was evidence suggesting that hyaluronic acid (HA) can protect mitochondria from oxidative stress in chondrocytes, but its protective effects and mechanism in nucleus pulposus cells (NPCs) remain unclear. This study aimed to confirm the effect of HA promoting mitophagy and protecting mitochondria function in NPCs, and explore its underlying mechanism. NPCs were treated with high molecular weight HA, tert-butyl hydroperoxide (TBHP) and Cyclosporin A (CsA). Mitophagy, mitochondrial function, apoptosis, senescence and extracellular matrix (ECM) degradation were measured. Then, NPCs were transfected with C1QBP siRNA, mitophagy and mitochondrial function were tested. The therapeutic effects of HA on IDD by promoting mitophagy were assessed in bovine intervertebral disc organ culture model. The results showed that TBHP induced oxidative stress, mitochondrial dysfunction, NPCs apoptosis, senescence and ECM degradation. Treated by HA, mitophagy was activated, concomitantly, mitochondrial dysfunction, apoptosis, senescence and ECM degradation were ameliorated. Mitophagy inhibition by CsA partially eliminated the protective effects of HA against oxidative stress. After transfected with C1QBP siRNA to reduce the expression of C1QBP in NPCs, the effect of HA promoting mitophagy was inhibited and the protective effect of HA against oxidative stress was weaken. Additionally, HA alleviated NPCs apoptosis and ECM degradation in bovine intervertebral disc organ culture model. These findings suggest that HA can protect mitochondrial function through activation of mitophagy in NPCs and ameliorate IDD. Furthermore, C1QBP is involved in HA promoting mitophagy and protecting NPCs from oxidative stress. Taken together, our results provide substantial evidence for the clinical applications of HA in the prevention and treatment of IDD.

The therapeutic effects of low-intensity pulsed ultrasound in musculoskeletal soft tissue injuries: Focusing on the molecular mechanism

Musculoskeletal soft tissue injuries are very common and usually occur during both sporting and everyday activities. The intervention of adjuvant therapies to promote tissue regeneration is of great importance to improving people's quality of life and extending their productive lives. Though many studies have focused on the positive results and effectiveness of the LIPUS on soft tissue, the molecular mechanisms standing behind LIPUS effects are much less explored and reported, especially the intracellular signaling pathways. We incorporated all research on LIPUS in soft tissue diseases since 2005 and summarized studies that uncovered the intracellular molecular mechanism. This review will also provide the latest evidence-based research progress in this field and suggest research directions for future experiments.

HYDRHA: Hydrogels of hyaluronic acid. New biomedical approaches in cancer, neurodegenerative diseases, and tissue engineering

In the last decade, hyaluronic acid (HA) has attracted an ever-growing interest in the biomedical engineering field as a biocompatible, biodegradable, and chemically versatile molecule. In fact, HA is a major component of the extracellular matrix (ECM) and is essential for the maintenance of cellular homeostasis and crosstalk. Innovative experimental strategies in vitro and in vivo using three-dimensional (3D) HA systems have been increasingly reported in studies of diseases, replacement of tissue and organ damage, repairing wounds, and encapsulating stem cells for tissue regeneration. The present work aims to give an overview and comparison of recent work carried out on HA systems showing advantages, limitations, and their complementarity, for a comprehensive characterization of their use. A special attention is paid to the use of HA in three important areas: cancer, diseases of the central nervous system (CNS), and tissue regeneration, discussing the most innovative experimental strategies. Finally, perspectives within and beyond these research fields are discussed.

Oxidized hyaluronic acid/adipic acid dihydrazide hydrogel as cell microcarriers for tissue regeneration applications

Hyaluronic acid (HA) is a biopolymer present in various human tissues, whose degradation causes tissue damage and diseases. The oxidized hyaluronic acid/adipic acid dihydrazide (oxi-HA/ADH) hydrogels have attracted attention due to their advantages such as thermosensitivity, injectability, in situ gelation, and sterilization. However, studies are still scarce in the literature as microcarriers. In that sense, this work is a study of oxi-HA/ADH microparticles of 215.6 ± 2.7 µm obtained by high-speed shearing (18,000 rpm at pH 7) as cell microcarriers. Results showed that BALB/c 3T3 fibroblasts and adipose mesenchymal stem cells (h-AdMSC) cultured on the oxi-HA/ADH microcarriers presented a higher growth of both cells in comparison with the hydrogel. Moreover, the extrusion force of oxi-HA/ADH microparticles was reduced by 35% and 55% with the addition of 25% and 75% HA fluid, respectively, thus improving its injectability. These results showed that oxi-HA/ADH microcarriers can be a potential injectable biopolymer for tissue regeneration applications.

Emerging pharmaceutical therapeutics and delivery technologies for osteoarthritis therapy

Osteoarthritis (OA) is one of the most common joint degenerative diseases in the world. At present, the management of OA depends on the lifestyle modification and joint replacement surgery, with the lifespan of prosthesis quite limited yet. Effective drug treatment of OA is essential. However, the current drugs, such as the non-steroidal anti-inflammatory drugs and acetaminophen, as well as glucosamine, chondroitin sulfate, hyaluronic acid, are accompanied by obvious side effects, with the therapeutic efficacy to be enhanced. Recently, novel reagents such as IL-1 antagonists and nerve growth factor inhibitors have entered clinical trials. Moreover, increasing evidence demonstrated that active ingredients of natural plants have great potential for treating OA. Meanwhile, the use of novel drug delivery strategies may overcome the shortcomings of conventional preparations and enhance the bioavailability of drugs, as well as decrease the side effects significantly. This review therefore summarizes the pathological mechanisms, management strategies, and research progress in the drug molecules including the newly identified active ingredient derived from medicinal plants for OA therapy, with the drug delivery technologies also summarized, with the expectation to provide the summary and outlook for developing the next generation of drugs and preparations for OA therapy.

The Booster Effect of a Single Quarterly Dose of Hyaluronic Acid in Knee Osteoarthritis: Five-Year Results of a Registry-Based Study

Objective

Viscosupplementation by hyaluronic acid (HA) is well established non-surgical treatment of knee osteoarthritis (KOA). This registry-based study investigated the booster effect of a quarterly intra-articular single knee injection (30mg/2ml) for five years.

Methods

Sixty patients, including 29 males and 31 females, with a mean ± SD age 61.07 ± 9.15 with Kellgren-Lawrence grade I-III KOA, have been selected from a registry of interventional treatments for musculoskeletal pain conditions. To be eligible, patients had to be treated with a single quarterly intraarticular injection of HA with a follow-up of at least five years and assessed with Western Ontario and McMaster Universities Arthritis Index (WOMAC) and Numeric Rating Scale (NRS) at baseline and after each HA injection in the first 24 months and at 36, 48, and 60 months.

Results

Sixty of 63 patients enrolled in this study completed the 60 months of follow-up. Patients had a marked improvement in knee function and pain, expressed by the significant reduction in WOMAC (T0 48.62±8.95 vs. T11 10.75±4.36; p<0.0001) and NRS scores (6.38±1.06 vs. T11 0.95±0.89 p<0.0001) from the baseline to the end of the follow-up period.

Conclusion

A quarterly injection of HA provides a rapid, safe, and stable long-term reduction of pain and improvement of function in elderly people with mild to moderate knee osteoarthritis along a five-year period of treatment and follow-up. Further investigations are necessary to confirm these findings.

Fabrication Strategies Towards Hydrogels for Biomedical Application: Chemical and Mechanical Insights

This review aims at giving selected chemical and mechanical insights on design criteria that should be taken into account in hydrogel production for biomedical applications. Particular emphasis will be given to the chemical aspects involved in hydrogel design: macromer chemical composition, cross-linking strategies and chemistry towards "conventional" and smart/stimuli responsive hydrogels. Mechanical properties of hydrogels in view of regenerative medicine applications will also be considered.

BRAZILIAN CONSENSUS STATEMENT ON VISCOSUPPLEMENTATION OF THE HIP (COBRAVI-Q)

OBJECTIVE

The Brazilian Consensus on Hip Viscosupplementation aims to generate a referential and consensual source from the theoretical knowledge and clinical experience of specialists in the field.

METHODS

A multidisciplinary panel was formed with 15 specialists (sports medicine, orthopedists, physiatrists and rheumatologists), based on clinical and academic experience in the use of viscosupplementation of the hip. 12 statements were prepared, discussed and voted. Each panelist gave a value between 0 and 10 on a Likert scale, specifying their level of agreement with the statement.

RESULTS

The panel reached a consensus on several aspects of viscosupplementation of the hip, with emphasis on the following statements: best indication is for mild to moderate hip arthrosis; it may be indicated in severe osteoarthritis; results may vary according to the characteristics of the viscosupplement used; Viscosupplementation should not be performed as an isolated procedure, but in conjunction with other rehabilitation and pharmacological measures; best injection technique should be based on anatomical references coupled with imaging guidance; it is a cost-effective procedure.

CONCLUSION

Viscosupplementation is a safe and effective therapy for hip osteoarthritis, even in severe cases. Guided injection is recommended. Level of Evidence V, Expert Opinion.

Dynamic covalent crosslinked hyaluronic acid hydrogels and nanomaterials for biomedical applications

Hyaluronic acid (HA), one of the main components of the extracellular matrix (ECM), is extensively used in the design of hydrogels and nanoparticles for different biomedical applications due to its critical role in vivo, degradability by endogenous enzymes, and absence of immunogenicity. HA-based hydrogels and nanoparticles have been developed by utilizing different crosslinking chemistries. The development of such crosslinking chemistries indicates that even subtle differences in the structure of reactive groups or the procedure of crosslinking may have a profound impact on the intended mechanical, physical and biological outcomes. There are widespread examples of modified HA polymers that can form either covalently or physically crosslinked biomaterials. More recently, studies have been focused on dynamic covalent crosslinked HA-based biomaterials since these types of crosslinking allow the preparation of dynamic structures with the ability to form in situ, be injectable, and have self-healing properties. In this review, HA-based hydrogels and nanomaterials that are crosslinked by dynamic-covalent coupling (DCC) chemistry have been critically assessed.

Public Interest in Hyaluronic Acid Injections for Knee Osteoarthritis in the United States and Europe: An International Google Trends Analysis

Background

Hyaluronic acid injections remain a common nonsurgical alternative for the treatment of knee osteoarthritis despite limited clinical evidence and varying global recommendations regarding its use. We used the Google Trends tool to provide a quantitative analysis of public interest in hyaluronic acid injections for knee osteoarthritis in the United States and Europe.

Methods

We customized Google Trends parameters to obtain search data from January 2009 to December 2019 in both the United States and Europe. Combinations of "arthritis", "osteoarthritis", "hyaluronic acid", "knee arthritis", "knee osteoarthritis", and "knee injection" were entered into the Google Trends tool, and trend analyses were performed.

Results

The models generated to describe public interest in hyaluronic acid for knee injections in both the United States and Europe showed increased Google queries as time progressed (P < .001). The United States growth model displayed linear growth (r² = 0.90) while the European growth model displayed exponential growth (r² = 0.90).

Conclusions

Our results indicate a significant increase in Google queries related to hyaluronic acid injections for knee osteoarthritis since 2009 in both the United States and Europe. Our models suggest that despite mixed evidence supporting its use, orthopedic surgeons should expect continued public interest in hyaluronic acid for knee osteoarthritis. The results of our study may help to prepare surgeons for patient inquiries, inform the creation of evidence-based shared decision-making tools, and direct future research.

State-of-the-art glycosaminoglycan characterization

Glycosaminoglycans (GAGs) are heterogeneous acidic polysaccharides involved in a range of biological functions. They have a significant influence on the regulation of cellular processes and the development of various diseases and infections. To fully understand the functional roles that GAGs play in mammalian systems, including disease processes, it is essential to understand their structural features. Despite having a linear structure and a repetitive disaccharide backbone, their structural analysis is challenging and requires elaborate preparative and analytical techniques. In particular, the extent to which GAGs are sulfated, as well as variation in sulfate position across the entire oligosaccharide or on individual monosaccharides, represents a major obstacle. Here, we summarize the current state-of-the-art methodologies used for GAG sample preparation and analysis, discussing in detail liquid chromatograpy and mass spectrometry-based approaches, including advanced ion activation methods, ion mobility separations and infrared action spectroscopy of mass-selected species.

Bactericidal/Permeability-Increasing Protein Downregulates the Inflammatory Response in In Vivo Models of Arthritis

We investigated the effects of bactericidal/permeability-increasing protein (BPI) alone or in combination with hyaluronic acid (HA) in two animal models: collagen-induced arthritis (CIA) and crystal-induced inflammation. In CIA, mice were intraperitoneally injected with PBS, HA, or BPI plus or minus HA, twice a week for 2 months, and then euthanized to collect paw and blood. Arthritis was assessed in ankle joints by clinical and histological evaluation. Pathogenic crystals were intraperitoneally injected in mice plus or minus BPI, or with a composition of BPI and HA. After sacrifice, total and differential leukocyte counts were determined. Cytokine levels were measured in serum and peritoneal fluids. In CIA mice, BPI improved clinical and histological outcomes (histological scores ≥2-fold), and downregulated inflammatory mediators (47–93%). In crystal-induced inflammation, BPI reduced leukocyte infiltration (total count: ≥60%; polymorphonuclear cells: ≥36%) and inhibited cytokine production (35–74%). In both models, when mice were co-treated with BPI and HA, the improvement of all parameters was greater than that observed after administration of the two substances alone. Results show that BPI attenuates CIA and inflammation in mice, and this effect is enhanced by HA co-administration. Combined use of BPI and HA represents an interesting perspective for new potential treatments in arthritis.

Counts of hyaluronic acid-containing extracellular vesicles decrease in naturally occurring equine osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease with inadequately understood pathogenesis leading to pain and functional limitations. Extracellular vesicles (EVs) released by synovial joint cells can induce both pro- and anti-OA effects. Hyaluronic acid (HA) lubricates the surfaces of articular cartilage and is one of the bioactive molecules transported by EVs. In humans, altered EV counts and composition can be observed in OA synovial fluid (SF), while EV research is in early stages in the horse-a well-recognized OA model. The aim was to characterize SF EVs and their HA cargo in 19 horses. SF was collected after euthanasia from control, OA, and contralateral metacarpophalangeal joints. The SF HA concentrations and size distribution were determined with a sandwich-type enzyme-linked sorbent assay and size-exclusion chromatography. Ultracentrifugation followed by nanoparticle tracking analysis (NTA) were utilized to quantify small EVs, while confocal laser scanning microscopy (CLSM) and image analysis characterized larger EVs. The number and size distribution of small EVs measured by NTA were unaffected by OA, but these results may be limited by the lack of hyaluronidase pre-treatment of the samples. When visualized by CLSM, the number and proportion of larger HA-containing EVs (HA-EVs) decreased in OA SF (generalized linear model, count: p = 0.024, %: p = 0.028). There was an inverse association between the OA grade and total EV count, HA-EV count, and HA-EV % (r_s = - 0.264 to - 0.327, p = 0.012-0.045). The total HA concentrations were also lower in OA (generalized linear model, p = 0.002). To conclude, the present study discovered a potential SF biomarker (HA-EVs) for naturally occurring equine OA. The roles of HA-EVs in the pathogenesis of OA and their potential as a joint disease biomarker and therapeutic target warrant future studies.

Recent Progress on Hyaluronan-Based Products for Wound Healing Applications

Hyaluronic acid (HA) based nanocomposites are considered excellent for improving wound healing. HA is biocompatible, biodegradable, non-toxic, biologically active, has hemostatic ability, and resists bacterial adhesion. HA-based nanocomposites promote wound healing in four different sequential phases hemostasis, inflammation, proliferation, and maturation. The unique biological characteristics of HA enable it to serve as a drug, an antibacterial agent, and a growth factor, which combine to accelerate the healing process. In this review, we focus on the use of HA-based nanocomposites for wound healing applications and we describe the importance of HA for the wound healing process in each sequential phase, such as hemostasis, inflammation, proliferation, and maturation. Metal nanoparticles (MNPs) or metal oxide nanoparticles (MO-NPs) loaded with HA nanocomposite are used for wound healing applications. Insights into important antibacterial mechanisms are described in HA nanocomposites. Furthermore, we explain antibiotics loaded with HA nanocomposite and its combination with the MNPs/MO-NPs used for wound healing applications. In addition, HA derivatives are discussed and used in combination with the other polymers of the composite for the wound healing process, as is the role of the polymer in wound healing applications. Finally, HA-based nanocomposites used for clinical trials in animal models are presented for wound healing applications.

Joint together: The etiology and pathogenesis of ankylosing spondylitis

Spondyloarthritis (SpA) refers to a group of diseases with inflammation in joints and spines. In this family, ankylosing spondylitis (AS) is a rare but classic form that mainly involves the spine and sacroiliac joint, leading to the loss of flexibility and fusion of the spine. Compared to other diseases in SpA, AS has a very distinct hereditary disposition and pattern of involvement, and several hypotheses about its etiopathogenesis have been proposed. In spite of significant advances made in Th17 dynamics and AS treatment, the underlying mechanism remains concealed. To this end, we covered several topics, including the nature of the immune response, the microenvironment in the articulation that is behind the disease's progression, and the split between the hypotheses and the evidence on how the intestine affects arthritis. In this review, we describe the current findings of AS and SpA, with the aim of providing an integrated view of the initiation of inflammation and the development of the disease.

A novel immuno-device based on the specific binding of AuNP-supported CTAB with biotinylated antibody of hyaluronic acid toward an early-stage recognition of a biomarker: a bioanalytical assay in real samples using disposal biosensor technology

Hyaluronic Acid (HA) is a non-sulfated glycosaminoglycan, which is a potential biomarker that could be evaluated in the diagnosis of some cancers. For the first time, a novel label-free electrochemical immunosensor was developed based on modified ITO-PET (indium tin oxide-polyethylene terephthalate) electrodes for the sensitive recognition of hyaluronic acid (HA) in real samples. A disposable ITO-coated PET electrode was modified with gold nanoparticles (AuNPs) to construct a suitable substrate for the efficient immobilization of biotinylated antibodies of HA. Importantly, the encapsulation of biotinylated antibody of HA in KCC1-NH-CS2 was performed successfully, which was another innovative part of this bio-device construction. For determining the immobilization steps and optimization of the biosensor, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques were used. Furthermore, the morphological characterization of each ITO electrode surface was performed by field emission scanning electron microscopy (FESEM). Specific binding of gold nanoparticles supported CTAB to ITO-PET and its bioconjugation with the biotinylated antibody of HA was studied using the electroanalysis of the sensor performance. For the better performance of the antibody to generate an immunocomplex with HA (antigen), its encapsulation was performed, which led to the excellent behavior of the immunosensor. The proposed HA immunosensor indicated excellent reproducibility, high selectivity, and long-term stability. The HA electrochemical immunosensor performed perfectly with a wide determination range (0.078 to 160 ng mL-1) and a low limit of quantification (0.078 ng mL-1) in human plasma samples. It is recommended that the designed biosensor can be used as a diagnostic tool in clinical bioassays in the near future.

Efficacy of computer-guided versus conventional sodium hyaluronate injection in superior joint space in treatment of temporomandibular joint (TMJ) internal derangement: Comparative randomized controlled trial

OBJECTIVES

evaluate the feasibility and clinical outcomes of computer-guided sodium hyaluronate injection in superior joint space compared to conventional injection for the treatment of TMJ Internal Derangement (TMJ-ID).

PATIENTS AND METHODS

Randomized controlled trial conducted on 40 patients diagnosed with bilateral TMJ-ID divided into two groups. Group A treated with four computer-guided sodium hyaluronate injections in superior TMJ space with one-week intervals. Group B received similar injections but with the conventional method. The intraoperative assessment included total procedural time and patient convenience during the injection. The postoperative evaluation included maximum unassisted mouth opening (MUMO), modified Helkimo's clinical dysfunction index, and pain intensity on a visual analog scale (VAS).

RESULTS

Group A showed better improvement in maximum mouth opening and pain intensity than group B after a week of the second, third and fourth injection. At the six months, group A continued to show better improvement regarding maximum mouth opening, while improvement in pain and TMJ dysfunction was similar in both groups. There were differences between both groups regarding procedural time and patient convenience across the study except the time of the first injection, which was similar in both groups CONCLUSION: Using the virtual planning and injection guide for intra-articular TMJ injection is considered promising to increase the accuracy and efficacy of injectable material securing faster results besides rendering the procedure easily reproducible and simpler to both clinicians and patients. However, the authors could not ensure the long-term superiority of the computer-guided injection technique over the conventional one in light of the results of this study.

Hyaluronic Acid-Based Nanomaterials Applied to Cancer: Where Are We Now?

Cancer cells normally develop the ability to rewire or reprogram themselves to become resistant to treatments that were previously effective. Despite progress in understanding drug resistance, knowledge gaps remain regarding the underlying biological causes of drug resistance and the design of cancer treatments to overcome it. So, resistance acquisition remains a major problem in cancer treatment. Targeted therapeutics are considered the next generation of cancer therapy because they overcome many limitations of traditional treatments. Numerous tumor cells overexpress several receptors that have a high binding affinity for hyaluronic acid (HA), while they are poorly expressed in normal body cells. HA and its derivatives have the advantage of being biocompatible and biodegradable and may be conjugated with a variety of drugs and drug carriers for developing various formulations as anticancer therapies such as micelles, nanogels, and inorganic nanoparticles. Due to their stability in blood circulation and predictable delivery patterns, enhanced tumor-selective drug accumulation, and decreased toxicity to normal tissues, tumor-targeting nanomaterial-based drug delivery systems have been shown to represent an efficacious approach for the treatment of cancer. In this review, we aim to provide an overview of some in vitro and in vivo studies related to the potential of HA as a ligand to develop targeted nanovehicles for future biomedical applications in cancer treatment.

The role of hyaluronic acid in polidocanol foam: An in vitro study

Objective

To study the role of hyaluronic acid (HA) in polidocanol (POL) foam.

Methods

The dose-dependent effect of HA-POL on cultured human umbilical vein endothelial cells (HUVECs) as well as foam stability was evaluated by measuring optical density (OD) values and foam half-life time (FHT), respectively. An in vitro model was utilized for estimating the foam blood-displacement capacity by adopting maximum displacement distance (MDD) and displacement time. A comparison of foam viscosity was also carried out.

Results

The OD values of HUVECs treated with HA first increased and then decreased with the growing dosage of HA while cells treated with HA-POL died. Both FHT and displacement time were prolonged statistically with a gradually enhanced foam viscosity. As to MDD, there were no significant differences.

Conclusions

HA was found to promote HUVECs proliferation slightly, but this was almost negligible when compared to the cell-killing capacity of 1% POL. The viscosity of POL foam was enhanced by HA indicating its positive correlation with both stability and displacement capacity of POL foam.

Combinatorial approaches of nanotherapeutics for inflammatory pathway targeted therapy of prostate cancer

Prostate cancer (PC) is the most prevalent male urogenital cancer worldwide. PC patients presenting an advanced or metastatic cancer succumb to the disease, even after therapeutic interventions including radiotherapy, surgery, androgen deprivation therapy (ADT), and chemotherapy. One of the hallmarks of PC is evading immune surveillance and chronic inflammation, which is a major challenge towards designing effective therapeutic formulations against PC. Chronic inflammation in PC is often characterized by tumor microenvironment alterations, epithelial-mesenchymal transition and extracellular matrix modifications. The inflammatory events are modulated by reactive nitrogen and oxygen species, inflammatory cytokines and chemokines. Major signaling pathways in PC includes androgen receptor, PI3K and NF-κB pathways and targeting these inter-linked pathways poses a major therapeutic challenge. Notably, many conventional treatments are clinically unsuccessful, due to lack of targetability and poor bioavailability of the therapeutics, untoward toxicity and multidrug resistance. The past decade witnessed an advancement of nanotechnology as an excellent therapeutic paradigm for PC therapy. Modern nanovectorization strategies such as stimuli-responsive and active PC targeting carriers offer controlled release patterns and superior anti-cancer effects. The current review initially describes the classification, inflammatory triggers and major inflammatory pathways of PC, various PC treatment strategies and their limitations. Subsequently, recent advancement in combinatorial nanotherapeutic approaches, which target PC inflammatory pathways, and the mechanism of action are discussed. Besides, the current clinical status and prospects of PC homing nanovectorization, and major challenges to be addressed towards the advancement PC therapy are also addressed.

Multimodal Multidisciplinary Management of Patients with Moderate to Severe Pain in Knee Osteoarthritis: A Need to Meet Patient Expectations

Knee osteoarthritis (OA) is one of the most common and disabling medical conditions. In the case of moderate to severe pain, a single intervention may not be sufficient to allay symptoms and improve quality of life. Examples include first-line, background therapy with symptomatic slow-acting drugs for OA (SYSADOAs) or non-steroidal anti-inflammatory drugs (NSAIDs). Therefore, the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) performed a review of a multimodal/multicomponent approach for knee OA therapy. This strategy is a particularly appropriate solution for the management of patients affected by knee OA, including those with pain and dysfunction reaching various thresholds at the different joints. The multimodal/multicomponent approach should be based, firstly, on different combinations of non-pharmacological and pharmacological interventions. Potential pharmacological combinations include SYSADOAs and NSAIDs, NSAIDs and weak opioids, and intra-articular treatments with SYSADOAs/NSAIDs. Based on the available evidence, most combined treatments provide benefit beyond single agents for the improvement of pain and other symptoms typical of knee OA, although further high-quality studies are required. In this work, we have therefore provided new, patient-centered perspectives for the management of knee OA, based on the concept that a multimodal, multicomponent, multidisciplinary approach, applied not only to non-pharmacological treatments but also to a combination of the currently available pharmacological options, will better meet the needs and expectations of patients with knee OA, who may present with various phenotypes and trajectories.

Hyaluronic Acid Oligosaccharide Derivatives Alleviate Lipopolysaccharide-Induced Inflammation in ATDC5 Cells by Multiple Mechanisms

High molecular weight hyaluronic acids (HMW-HAs) have been used for the palliative treatment of osteoarthritis (OA) for decades, but the pharmacological activity of HA fragments has not been fully explored due to the limited availability of structurally defined HA fragments. In this study, we synthesized a series glycosides of oligosaccharides of HA (o-HAs), hereinafter collectively referred to as o-HA derivatives. Their effects on OA progression were examined in a chondrocyte inflammatory model established by the lipopolysaccharide (LPS)-challenged ATDC5 cells. Cell Counting Kit-8 (CCK-8) assays and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) showed that o-HA derivatives (≤100 μg/mL) exhibited no cytotoxicity and pro-inflammatory effects. We found that the o-HA and o-HA derivatives alleviated LPS-induced inflammation, apoptosis, autophagy and proliferation-inhibition of ATDC5 cells, similar to the activities of HMW-HAs. Moreover, Western blot analysis showed that different HA derivatives selectively reversed the effects of LPS on the expression of extracellular matrix (ECM)-related proteins (MMP13, COL2A1 and Aggrecan) in ATDC5 cells. Our study suggested that o-HA derivatives may alleviate LPS-induced chondrocyte injury by reducing the inflammatory response, maintaining cell proliferation, inhibiting apoptosis and autophagy, and decreasing ECM degradation, supporting a potential oligosaccharides-mediated therapy for OA.

Independent Control of Molecular Weight, Concentration, and Stiffness of Hyaluronic Acid Hydrogels

Hyaluronic acid (HA) hydrogels have been used for a multitude of applications, perhaps most notably for tissue engineering and regenerative medicine, owing to the versatility of the polymer and its tunable nature. Various groups have investigated the impact of hydrogel parameters (e.g., molecular weight, concentration, stiffness, etc.) in vitro and in vivo to achieve desired material performance characteristics. A limitation in the literature to date has been that altering one hydrogel parameter (a 'manipulated variable') to achieve a given hydrogel characteristic (a 'controlled variable') changes two variables at a time (e.g., altering molecular weight and/or concentration to investigate cell response to stiffness). Therefore, if cell responses differ, it may be possible that more than one variable caused the changes in observed responses. In the current study, we leveraged thiol-ene click chemistry with a crosslinker to develop a method that minimizes material performance changes and permitted multiple material properties to be independently held constant to evaluate a single variable at a time. Independent control was accomplished by tuning the concentration of crosslinker to achieve an effectively constant stiffness for different HA hydrogel molecular weights and polymer concentrations. Specific formulations were thereby identified that enabled the molecular weight (76 - 1550 kDa), concentration (2 - 10%), or stiffness (~1 - 350 kPa) to be varied while the other two were held constant, a key technical achievement. The response of rat mesenchymal stem cells to varying molecular weight, concentration, and stiffness demonstrated consistent upregulation of osteocalcin gene expression. The methodology presented to achieve independent control of hydrogel parameters may potentially be adopted by others for alternative hydrogel polymers, cell types, or cell culture medium compositions to minimize confounding variables in experimental hydrogel designs.

Effect of hyaluronic acid on cytokines and immune cells change in patients of knee osteoarthritis

Purpose

To evaluate the changes of cytokines and immune cells after Intra-articular hyaluronic acid(IAHA)injections in patients with knee osteoarthritis (KOA).

Patients and Methods

Sixteen patients were included in the study, with a total of 65 IAHA injections. The Numeric Rating Scale (NRS) and Lysholm scores were evaluated at each visit. The immune cells and 14 cytokines of synovial fluid were analyzed at each visit. The association between immune cells and cytokines were examined.

Results

IL-6 and IL-8 were the most common cytokines in the synovial fluid of KOA patients. The synovial fluid was orchestrated by macrophages (69%) and Lymphocytes (18%). Neutrophils were less to count of the total cell population (< 2%). The cytokines decreased significantly after the first injection and then tended to be stable. Lymphocytes increased a lot, while Macrophages decreased in the early stage, then increased after multiple injections. The proposition of M1 decreased in the early stage, then increased after multiple injections, while M2 increased consistently. M1 and M2 were positively associated with IL-6 and IL-8.

Conclusion

The synovial fluid of KOA patients was orchestrated by macrophages (69%) and Lymphocytes (18%) and cytokines like IL-6 and IL-8. IAHA may play an anti-inflammatory functional role through the decreased production of IL-6 and IL-8 by macrophages through polarization. The results from this study partially revealed the effect of IAHA on cytokines and immune cells change in KOA patients, and therapies targeting pathogenic cytokines and immune cells might be used to attenuate the knee joint inflammation and release pain.

Trial registration

ChiCTR2100050133; date registered 17 August 2021.

Hyaluronic Acid: A Review of the Drug Delivery Capabilities of This Naturally Occurring Polysaccharide

The inclusion of physiologically active molecules into a naturally occurring polymer matrix can improve the degradation, absorption, and release profile of the drug, thus boosting the therapeutic impact and potentially even reducing the frequency of administration. The human body produces significant amounts of polysaccharide hyaluronic acid, which boasts exceptional biocompatibility, biodegradability, and one-of-a-kind physicochemical features. In this review, we will examine the clinical trials currently utilizing hyaluronic acid and address the bright future of this versatile polymer, as well as summarize the numerous applications of hyaluronic acid in drug delivery and immunomodulation.

High Molecular Weight Hyaluronic Acid Reduces the Expression of Virulence Genes fimA, mfa1, hagA, rgpA, and kgp in the Oral Pathogen Porphyromonas gingivalis

Porphyromonas gingivalis (P. gingivalis) is a cornerstone pathogen in the development and progression of periodontal and peri-implant tissue destruction. It is capable of causing dysbiosis of the microbial biofilm and modulation of the host immune system. Hyaluronic acid (HA) is a naturally occurring glycosaminoglycan found in all living organisms. It is well known and has been used for improving tissue healing. In addition, some studies have suggested that there may be an antimicrobial potential to HA. The aim of this study was to evaluate the effect of hyaluronic acid, azithromycin (AZM), and chlorhexidine (CHX) on the expression of genes (i.e., fimA, mfa1, hagA, rgpA, rgpB, and kgp) related to the virulence and adhesion of P. gingivalis. The study groups were divided into four: (1) HA treated group; (2) AZM treated group; (3) CHX treated group; and (4) untreated group to serve as a negative control. P. gingivalis ATCC 33277 was cultured and then exposed to four different concentrations (100% MIC, 50% MIC, 25% MIC, and 12.5% MIC) of HA, AZM, and CHX for 24 h. The expression levels of the aforementioned genes were measured using quantitative reverse transcription polymerase chain reaction (RT-qPCR). Relative fold-change values were calculated and compared between groups. The fold-change values of all genes combined were 0.46 ± 0.33, 0.31 ± 0.24, and 0.84 ± 0.77 for HA, AZM, and CHX, respectively. HA has downregulated all the genes by mostly a half-fold: 0.35 ± 0.20, 0.47 ± 0.35, 0.44 ± 0.25, 0.67 ± 0.46, 0.48 ± 0.33 and 0.35 ± 0.22 with fimA, mfa1, hagA, rgpA, rgpB and kgp, respectively. The effect of HA was significant on all genes except rgpB compared to the untreated control. Lower concentrations of HA tended to exhibit greater downregulation with 1 mg/mL being the most effective. High molecular weight (1.5 MDa) hyaluronic acid has a potent effect on P. gingivalis by downregulating fimA, mfa1, hagA, rgpA, and kgp. The effect of HA was generally less than that of AZM but greater than that of CHX.

A systematic review on the potential value of synovial fluid biomarkers to predict clinical outcomes in cartilage repair treatments

OBJECTIVE

Multiple biochemical biomarkers have been previously investigated for the diagnosis, prognosis and response to treatment of articular cartilage damage, including osteoarthritis (OA). Synovial fluid (SF) biomarker measurement is a potential method to predict treatment response and effectiveness. However, the significance of different biomarkers and their correlation to clinical outcomes remains unclear. This systematic review evaluated current SF biomarkers used in investigation of cartilage degeneration or regeneration in the knee joint and correlated these biomarkers with clinical outcomes following cartilage repair or regeneration interventions.

METHOD

PubMed, Institute of Science Index, Scopus, Cochrane Central Register of Controlled Trials, and Embase databases were searched. Studies evaluating SF biomarkers and clinical outcomes following cartilage repair intervention were included. Two researchers independently performed data extraction and Quality Assessment of Diagnostic Accuracy Score 2 (QUADAS-2) analysis. Biomarker inclusion, change following intervention and correlation with clinical outcome was compared.

RESULTS

9 studies were included. Study heterogeneity precluded meta-analysis. There was significant variation in sampling and analysis. 33 biomarkers were evaluated in addition to microRNA and catabolic/anabolic ratios. Five studies reported on correlation of biomarkers with six biomarkers significantly correlated with clinical outcomes following intervention. However, correlation was only demonstrated in isolated studies.

CONCLUSION

This review demonstrates significant difficulties in drawing conclusions regarding the importance of SF biomarkers based on the available literature. Improved standardisation for collection and analysis of SF samples is required. Future publications should also focus on clinical outcome scores and seek to correlate biomarkers with progression to further understand the significance of identified markers in a clinical context.

REGISTRATION NUMBER

PROSPERO CRD42022304298. Study protocol available on PROSPERO website.

Engineering of Viscosupplement Biomaterials for Treatment of Osteoarthritis: A Comprehensive Review

Osteoarthritis (OA) is a progressive degenerative disease that causes severe pain and functional limitation, especially during locomotion. It is the most common arthritis type that damages the surface of articular cartilage until the underlying bone. In the past decade, the scientific community has made a considerable effort to improve or discover therapeutical products used as a form of conservative treatment capable of restoring the damaged articular tissue, avoiding, as far as possible, the use of surgical practices. The most common and direct nonoperative application available for OA treatment is the viscosupplementation (VS) procedure that demonstrates a safe, effective method and is less painful for the patients. The most recent works dealing with the design, development, and validation of viscosupplement products in preclinical and clinical trials for OA treatment are overviewed herein. In general, despite the development of new products, hyaluronic acid continues to be among the most reported intra‐articular viscosupplement products used in clinical trials, typically used as an isolated product or conjugated with other biologicals or drugs, such as platelet‐rich plasma and corticosteroids (CS). However, this issue is still demanding innovation. Approaches comprising new biomaterials as VS products, with intrinsic bioactivity, economical, and environmental friendliness, are required.

3D Printable Dynamic Hydrogel: As Simple as it Gets!

3D Printing technology offers a vast range of applications for tissue engineering applications. Over the past decade a vast range of new equipment has been developed; while, 3D printable biomaterials, especially hydrogels, are investigated to fit the printability requirements. The current candidates for bioprinting often requires post-printing cross-linking to maintain their shape. On the other hand, dynamic hydrogels are considered as the most promising candidate for this application with their extrudability and self-healing properties. However, it proves to be very difficult to match the required rheological in a simple material. Here, we present for the first time the simplest formulation of a dynamic hydrogel based on thiol-functionalized hyaluronic acid formulated with gold ions that fulfill all the requirements to be printed without the use of external stimuli, as judged by the rheological studies. The printability was also demonstrated with a 3D printer allowing to print the dynamic hydrogel as it is, achieving 3D construct with a relatively good precision and up to 24 layers, corresponding to 10 mm high. This material is the simplest 3D printable hydrogel and its mixture with cells and biological compounds is expected to open a new era in 3D bioprinting. This article is protected by copyright. All rights reserved.

New Hyaluronic Acid from Plant Origin to Improve Joint Protection—An In Vitro Study

Background: In recent decades, hyaluronic acid (HA) has attracted great attention as a new treatment option for osteoarthritis. Classical therapies are not able to stop the cartilage degeneration process nor do they favor tissue repair. Nowadays, it is accepted that high molecular weight HA can reduce inflammation by promoting tissue regeneration; therefore, the aim of this study was to verify the efficacy of a new high molecular weight HA of plant origin (called GreenIuronic®) in maintaining joint homeostasis and preventing the harmful processes of osteoarthritis. Methods: The bioavailability of GreenIuronic® was investigated in a 3D intestinal barrier model that mimics human oral intake while excluding damage to the intestinal barrier. Furthermore, the chemical significance and biological properties of GreenIuronic® were investigated in conditions that simulate osteoarthritis. Results: Our data demonstrated that GreenIuronic® crosses the intestinal barrier without side effects as it has a chemical–biological profile, which could be responsible for many specific chondrocyte functions. Furthermore, in the osteoarthritis model, GreenIuronic® can modulate the molecular mechanism responsible for preventing and restoring the degradation of cartilage. Conclusion: According to our results, this new form of HA appears to be well absorbed and distributed to chondrocytes, preserving their biological activities. Therefore, the oral administration of GreenIuronic® in humans can be considered a valid strategy to obtain beneficial therapeutic effects during osteoarthritis.

Hyaluronic Acid: Its Versatile Use in Ocular Drug Delivery with a Specific Focus on Hyaluronic Acid-Based Polyelectrolyte Complexes

Extensive research is currently being conducted into novel ocular drug delivery systems (ODDS) that are capable of surpassing the limitations associated with conventional intraocular anterior and posterior segment treatments. Nanoformulations, including those synthesised from the natural, hydrophilic glycosaminoglycan, hyaluronic acid (HA), have gained significant traction due to their enhanced intraocular permeation, longer retention times, high physiological stability, inherent biocompatibility, and biodegradability. However, conventional nanoformulation preparation methods often require large volumes of organic solvent, chemical cross-linkers, and surfactants, which can pose significant toxicity risks. We present a comprehensive, critical review of the use of HA in the field of ophthalmology and ocular drug delivery, with a discussion of the physicochemical and biological properties of HA that render it a suitable excipient for drug delivery to both the anterior and posterior segments of the eye. The pivotal focus of this review is a discussion of the formation of HA-based nanoparticles via polyelectrolyte complexation, a mild method of preparation driven primarily by electrostatic interaction between opposing polyelectrolytes. To the best of our knowledge, despite the growing number of publications centred around the development of HA-based polyelectrolyte complexes (HA-PECs) for ocular drug delivery, no review articles have been published in this area. This review aims to bridge the identified gap in the literature by (1) reviewing recent advances in the area of HA-PECs for anterior and posterior ODD, (2) describing the mechanism and thermodynamics of polyelectrolyte complexation, and (3) critically evaluating the intrinsic and extrinsic formulation parameters that must be considered when designing HA-PECs for ocular application.

Microfluidic-driven mixing of high molecular weight polymeric complexes for precise nanoparticle downsizing

Chitosan (CHIT) and hyaluronic acid (HA) are two polysaccharides (PSs) with high value in several biomedical applications. In this study, we present a microfluidic method to synthetize CHIT-HA NPs to overcome the disadvantages of the dropwise approach generally used for nanoprecipitation of polyelectrolyte complexes. The proposed microfluidic approach enables to generate monodisperse suspensions of NPs with ≈100 nm of size compared to the dropwise method that generated ≈2 times bigger NPs. Finally, we evaluated the potential of obtained NPs in an inflammatory scenario. The treatment with NPs led to the reduction of the main inflammatory molecules produced by macrophages (PGE₂, IL-6, IL-8, MCAF and TNF-α) and fibroblasts (IL-1 α, PGE₂, TNF-α) stimulated with lipopolysaccharide or conditioned medium, respectively. This study demonstrates that our approach can be used to enhance the synthesis of nanocarriers based on bioactive macromolecules.

Development and Characterization of a Topically Deliverable Prophylactic Against Oxidative Damage in Cochlear Cells

Hearing loss affects roughly 466 million people worldwide. While the causes of hearing loss are diverse, mechanistically, inflammation and oxidative stress have been identified as major players in hearing loss regardless of pathogenesis. Treatment options remain extremely limited and there is currently no FDA approved drug therapy. Studies indicate that antioxidants such as d-Methionine have shown some protective effects; however, these studies involved systemic or invasive localized delivery methods and highlighted the need for the development of minimally invasive localized therapeutic approaches. Described herein is the development of an antioxidant-conjugated system that shows prophylactic potential against oxidative damage and appears suitable for topical delivery. Specifically, our covalent conjugate of hyaluronan with d-Methionine shows cytocompatibility and protection from oxidative stress in two mouse cochlear cell lines (HEI-OC1 and SV-k1). Mechanistically, the data indicate that the protective effects of the conjugate are due to the hyaluronan-mediated cellular internalization of the antioxidant. Most notably, the conjugate can efficiently permeate through an in vitro round window membrane model without the loss of the attached antioxidant, for subsequent delivery of the therapeutic cargo to the hearing sensory cells. Collectively these findings show that the novel conjugate could be a potential topical preventive agent against hearing loss.

Hyaluronic Acid-Based Nanomaterials as a New Approach to the Treatment and Prevention of Bacterial Infections

Bacterial contamination of medical devices is a great concern for public health and an increasing risk for hospital-acquired infections. The ongoing increase in antibiotic-resistant bacterial strains highlights the urgent need to find new effective alternatives to antibiotics. Hyaluronic acid (HA) is a valuable polymer in biomedical applications, partly due to its bactericidal effects on different platforms such as contact lenses, cleaning solutions, wound dressings, cosmetic formulations, etc. Because the pure form of HA is rapidly hydrolyzed, nanotechnology-based approaches have been investigated to improve its clinical utility. Moreover, a combination of HA with other bactericidal molecules could improve the antibacterial effects on drug-resistant bacterial strains, and improve the management of hard-to-heal wound infections. This review summarizes the structure, production, and properties of HA, and its various platforms as a carrier in drug delivery. Herein, we discuss recent works on numerous types of HA-based nanoparticles to overcome the limitations of traditional antibiotics in the treatment of bacterial infections. Advances in the fabrication of controlled release of antimicrobial agents from HA-based nanosystems can allow the complete eradication of pathogenic microorganisms.

Diagnosis and Management of Osteoarthritis with Hyaluronic Acid

BACKGROUND: Osteoarthritis (OA) of the genu joint is a degenerative disease of the genu joint, which due to functional limitations leads to deterioration of the quality of life of these patients. In many cases, surgical therapy prosthesis of articular surfaces represents the gold standard of treatment for these patients. AIM: In this study, it is proposed to evaluate the effectiveness of hyaluronic acid (HA) injected under the direction of Echo (ultrasound) in the genu articulation accompanied by a rehabilitation program. MATERIALS AND METHODS: Fifteen patients with knee OA were studied. According to the Kellgren-Lawrence radiological classification, Grade II-III arthrosis does not qualify for surgical treatment. Patients underwent intra-articular injection with HA, under ultrasound guidance, and after 6 days continued with rehabilitative treatment aimed at combating the patient’s analgesic posture, recovery of muscle traction participating in genu joint movement, decompression maneuvers, and decompaction in monopodial load. Patients were evaluated at the beginning and after 3 months. RESULTS: In the evaluation of patients at the beginning and after 3 months, a reduction in> 60% of the pain was found, and the Western Ontario and McMaster University Osteoarthritis test in 40% of patients after the first intra-articular injection. No significant side effects were observed during infiltrative procedures. CONCLUSIONS: This study confirms the effectiveness of the combined treatment of the rehabilitation program and intra-articular therapy under the guidance of Echos, in patients suffering from knee OA, significantly reducing pain and recovery of functional capacity.

Hyaluronic acid coated teriflunomide (A771726) loaded lipid carriers for the oral management of rheumatoid arthritis

Systemic rheumatoid arthritis treatment has been associated with numerous side effects. We attempted to formulate hyaluronic acid (HA)-coated teriflunomide (TER)-loaded nanostructured lipid carriers (NLCs) that can target inflamed rheumatic joints following oral administration. In vitro evaluation including colloidal characteristics, drug release and stability studies were conducted. Also, cytotoxicity studies on THP1 and peripheral blood mononuclear cells besides testing the binding of HA coated TER-NLCs to CD44 receptors were carried out. Furthermore, pharmacokinetics following oral administration, anti-arthritic effects, hepato and nephrotoxicity of NLCs were assessed. Selected NLCs formulation was approximately 284.9 ± 3.8 nm in size with 96.89 ± 0.45% entrapment efficiency and provided a sustained release for 30 days. NLCs showed good stability that was confirmed by TEM examination. Cell culture studies revealed that HA-coated TER- NLCs showed superior cytotoxicity and binding affinity to CD44 receptors compared with TER suspension. In vivo studies demonstrated the superiority of NLCs in increasing TER bioavailability, reducing TNF-α serum levels and improving joint healing that was evidenced in both histopathological and X-ray radiographic examination. This may be attributed to the ability of HA-coated TER-NLCs to target rheumatic joints passively and actively by targeting CD44 receptors that are overexpressed in rheumatic joints.

Progress of Platelet Derivatives for Cartilage Tissue Engineering

Articular cartilage has limited self-regeneration ability for lacking of blood vessels, nerves, and lymph that makes it a great challenge to repair defects of the tissue and restore motor functions of the injured or aging population. Platelet derivatives, such as platelet-rich plasma, have been proved effective, safe, and economical in musculoskeletal diseases for their autologous origin and rich in growth factors. The combination of platelet derivatives with biomaterials provides both mechanical support and localized sustained release of bioactive molecules in cartilage tissue engineering and low-cost efficient approaches of potential treatment. In this review, we first provide an overview of platelet derivatives and their application in clinical and experimental therapies, and then we further discuss the techniques of the addition of platelet derivatives and their influences on scaffold properties. Advances in cartilage tissue engineering with platelet derivatives as signal factors and structural components are also introduced before prospects and concerns in this research field. In short, platelet derivatives have broad application prospects as an economical and effective enhancement for tissue engineering–based articular cartilage repair.

Comparing the Risk of Osteonecrosis of the Femoral Head Following Intra-Articular Corticosteroid and Hyaluronic Acid Injections

BACKGROUND

Although intra-articular corticosteroid injections (CSIs) are a cornerstone in the nonoperative management of hip pathology, recent reports have raised concerns that they may cause osteonecrosis of the femoral head (ONFH). However, these studies might have been limited by nonrepresentative patient samples. Therefore, the purpose of this study was to assess the incidence of ONFH after CSI and compare it with the incidence in a similar patient population that received a non-CSI injection.

METHODS

This was a retrospective propensity-matched cohort study of patients in the MarketScan database who underwent an intra-articular hip injection from 2007 to 2017. Patients receiving hip CSIs were matched 4:1 with patients receiving hip hyaluronic acid injections (HAIs) based on age, sex, geographic region, comorbidities, type of hip pathology, injection year, and baseline and follow-up time using propensity scores. The patients' first injections were identified, and the time to development of ONFH was analyzed using Kaplan-Meier curves and Cox proportional-hazards models. Patients with a history of osteonecrosis or those who received both types of injections were excluded.

RESULTS

A total of 3,710 patients undergoing intra-articular hip injection were included (2,968 CSIs and 742 HAIs; mean [standard deviation] age, 53.1 [9.2] years; 55.4% men). All baseline factors were successfully matched between the groups (all p > 0.57). The estimated cumulative incidence (95% confidence interval [CI]) of ONFH for CSI and HAI patients was 2.4% (1.8% to 3.1%) versus 2.1% (1.1% to 3.5%) at 1 year and 2.9% (2.2% to 3.7%) versus 3.0% (1.7% to 4.8%) at 2 years (hazard ratio, 1.05; 95% CI, 0.59 to 1.84; p = 0.88). The results held across a range of sensitivity analyses.

CONCLUSIONS

The incidence of ONFH after intra-articular hip injection was similar between patients who received CSIs and those who received HAIs. Although this study could not determine whether intra-articular injections themselves (regardless of the drug that was used) lead to ONFH, the results suggest that ONFH after CSI often may be due, in part, to the natural course of the underlying disease. Future randomized controlled trials are needed to definitively answer this question; in the interim, clinicians may be reassured that they may continue judicious use of CSIs as clinically indicated.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Bioinspired Hydrogels as Platforms for Life-Science Applications: Challenges and Opportunities

Hydrogels, as interconnected networks (polymer mesh; physically, chemically, or dynamic crosslinked networks) incorporating a high amount of water, present structural characteristics similar to soft natural tissue. They enable the diffusion of different molecules (ions, drugs, and grow factors) and have the ability to take over the action of external factors. Their nature provides a wide variety of raw materials and inspiration for functional soft matter obtained by complex mechanisms and hierarchical self-assembly. Over the last decade, many studies focused on developing innovative and high-performance materials, with new or improved functions, by mimicking biological structures at different length scales. Hydrogels with natural or synthetic origin can be engineered as bulk materials, micro- or nanoparticles, patches, membranes, supramolecular pathways, bio-inks, etc. The specific features of hydrogels make them suitable for a wide variety of applications, including tissue engineering scaffolds (repair/regeneration), wound healing, drug delivery carriers, bio-inks, soft robotics, sensors, actuators, catalysis, food safety, and hygiene products. This review is focused on recent advances in the field of bioinspired hydrogels that can serve as platforms for life-science applications. A brief outlook on the actual trends and future directions is also presented.

Toll-like receptors and damage-associated molecular patterns in the pathogenesis of heart transplant rejection

Significant strides have been made in our understanding of the immune system and its role in cardiac transplant rejection. Despite the growing knowledge of immune responses, the mortality rate following cardiac transplantation remains grim. Related to procedural and pathological complications, toll-like receptor (TLR) and damage-associated molecular pattern (DAMP) signaling is the most direct and earliest interface between tissue integration and the innate immune response. This in turn can activate an adaptive immune response that further damages myocardial tissue. Furthermore, relevant literature on the status of DAMPs in the context of heart-transplantation remains limited, warranting further attention in clinical and translational research. This review aims to critically appraise the perspectives, advances, and challenges on DAMP-mediated innate immune response in the immune-mediated rejection of cardiac transplantation. Detailed analysis of the influence of TLR and DAMP signaling in mounting the immune response against the transplanted heart holds promise for improving outcomes through early detection and prevention of varied forms of organ rejection.

Intra-Articular Injections of Allogeneic Mesenchymal Stromal Cells vs. High Molecular Weight Hyaluronic Acid in Dogs With Osteoarthritis: Exploratory Data From a Double-Blind, Randomized, Prospective Clinical Trial

This double-blind, randomized, prospective clinical trial was conducted to obtain exploratory data comparing the efficacy of intra-articular allogeneic mesenchymal stem/stromal cells (MSC) to high molecular weight hyaluronic acid (HA) for the treatment of pain associated with canine osteoarthritis (OA). Objective gait analysis (%Body Weight Distribution, %BWD), accelerometry, clinical metrology instruments and veterinary exams were used as outcome measures during various time points throughout the 48-week study period. Fourteen dogs with elbow or coxofemoral OA were enrolled and assigned in a 2:1 ratio to the treatment groups. Each patient received a set of two injections 4 weeks apart. Self-limiting joint flare was observed in seven patients, with six of these in the MSC group. Ten patients completed all follow-up appointments. Both treatment groups showed evidence of mild improvement following the treatment, but the results were inconsistent among the various outcome measures assessed. Overall, dogs enrolled in the HA group showed greater improvement compared to the MSC group. The primary outcome measure, %BWD, showed evidence of improvement, when compared to baseline values, at 36 weeks after injection for the HA group only (p = 0.048, estimated difference: 4.7). Similarly, when treatment groups were compared, evidence of a difference between treatment groups (with the HA-group showing greater improvement) were identified for weeks 24 and 36 (p = 0.02 and 0.01, respectively). The small sample size of this exploratory study does not allow firm conclusions. However, until studies with larger sample sizes are available, the current literature combined with our data do not support the clinical use of intra-articular MSC therapy over high molecular weight HA for the treatment of canine OA at this time.

Impaired glucose metabolism underlies articular cartilage degeneration in osteoarthritis

Osteoarthritis (OA) is the leading joint disease characterized by cartilage destruction and loss of mobility. Accumulating evidence indicates that the incidence and severity of OA increases with diabetes, implicating systemic glucose metabolism in joint health. However, a definitive link between cellular metabolism in articular cartilage and OA pathogenesis is not yet established. Here, we report that in mice surgically induced to develop knee OA through destabilization of medial meniscus (DMM), expression of the main glucose transporter Glut1 is notably reduced in joint cartilage. Inducible deletion of Glut1 specifically in the Prg4-expressing articular cartilage accelerates cartilage loss in DMM-induced OA. Conversely, forced expression of Glut1 protects against cartilage destruction following DMM. Moreover, in mice with type I diabetes, both Glut1 expression and the rate of glycolysis are diminished in the articular cartilage, and the diabetic mice exhibit more severe cartilage destruction than their nondiabetic counterparts following DMM. The results provide proof of concept that boosting glucose metabolism in articular chondrocytes may ameliorate cartilage degeneration in OA.

Improved Joint Health Following Oral Administration of Glycosaminoglycans with Native Type II Collagen in a Rabbit Model of Osteoarthritis

Simple Summary

Osteoarthritis is an incurable chronic disease. For this reason, new therapies are constantly emerging to improve clinical signs and the quality of life of our pets. Chondroitin sulfate, glucosamine and hyaluronic acid have been proven effective and are the most widely used in many formulations. In the present study, adding native type II collagen to the combination of chondroitin sulfate, glucosamine and hyaluronic acid showed improvements on osteoarthritis progression in an experimental model of osteoarthritis induced by transection of the cranial cruciate ligament of the knee in New Zealand white rabbits. Disease progression was monitored at different time points using magnetic resonance imaging biomarkers, measurement of hyaluronic acid in synovial fluid, and macroscopic and microscopic evaluations of cartilage, synovial membrane and subchondral bone. Overall, our results showed that adding native type II collagen to a combination of glycosaminoglycans allows a significantly slower osteoarthritis progression, compared to glycosaminoglycans alone.

Abstract

A prospective, experimental, randomized, double blinded study was designed to evaluate the effects of glycosaminoglycans, with or without native type II collagen (NC), in an osteoarthritis model induced by cranial cruciate ligament transection. The following compounds were tested: chondroitin sulfate (CS), glucosamine hydrochloride (GlHCl), hyaluronic acid (HA) and NC. Fifty-four female 12-week-old New Zealand rabbits were classified into three groups: CTR (control–no treatment), CGH (CS + GlHCl + HA) and CGH-NC (CS + GlHCl + HA + NC). Each group was subdivided into three subgroups according to survival times of 24, 56 and 84 days. Over time, all rabbits developed degenerative changes associated with osteoarthritis. CGH-NC showed significantly improved values on macroscopic evaluation, compared to CTR and CGH. Microscopically, significantly better results were seen with CGH and CGH-NC, compared to CTR, and synovial membrane values were significantly better with CGH-NC compared to CGH. A significant improvement in magnetic resonance imaging biomarkers was also observed with CGH-NC in cartilage transversal relaxation time (T2) and subchondral bone D2D fractal dimension in the lateral condyle. In conclusion, our results show beneficial effects on joint health of CGH and CGH-NC and also supports that adding NC to CGH results in even greater efficacy.

A Review on Current Strategies for Extraction and Purification of Hyaluronic Acid

Since it is known that hyaluronic acid contributes to soft tissue growth, elasticity, and scar reduction, different strategies of producing HA have been explored in order to satisfy the current demand of HA in pharmaceutical products and formulations. The current interest deals with production via bacterial and yeast fermentation and extraction from animal sources; however, the main challenge is the right extraction technique and strategy since the original sources (e.g., fermentation broth) represent a complex system containing a number of components and solutes, which complicates the achievement of high extraction rates and purity. This review sheds light on the main pathways for the production of HA, advantages, and disadvantages, along with the current efforts in extracting and purifying this high-added-value molecule from different sources. Particular emphasis has been placed on specific case studies attempting production and successful recovery. For such works, full details are given together with their relevant outcomes.

Anti-Skin-Aging Effect of a Treatment with a Cosmetic Product and a Food Supplement Based on a New Hyaluronan: A Randomized Clinical Study in Healthy Women

Hyaluronic acid (HA) has long been used for its anti-age properties, as an ingredient in both topical applications and food supplements. In this study, a novel sodium hyaluronate, based on the innovative full spectrum technology, was administered as an ingredient of a cosmetic product and as the main constituent of a food supplement to evaluate its efficacy in counteracting skin ageing signs. Seventy-five female subjects were randomly assigned to the following treatments for 4 weeks: an active food supplement and a placebo cosmetic product, an active cosmetic product and a placebo food supplement, and a combination of the two products containing the active ingredient, that is, an “In&Out” treatment. The subjects used the placebo cosmetic product for another 14 days. Improvement of all the outcome measures (skin moisturization, elasticity, firmness and profilometry) was achieved by all treatments (p < 0.05); however, the combined treatment resulted in a further amelioration of the skin aging signs with respect to the two single active treatments (p < 0.001), and such effect lasted also after the follow-up period. In conclusion, such results confirmed that the concomitant administration of hyaluronans by these two different routes represents more than an interesting approach to counteract skin aging signs.