One intra-articular injection of hyaluronan prevents cell death and improves cell metabolism in a model of injured articular cartilage in the rabbit

HYBID in osteoarthritis: Potential target for disease progression

HYBID is a new hyaluronan-degrading enzyme and exists in various cells of the human body. Recently, HYBID was found to over-express in the osteoarthritic chondrocytes and fibroblast-like synoviocytes. According to these researches, high level of HYBID is significantly correlated with cartilage degeneration in joints and hyaluronic acid degradation in synovial fluid. In addition, HYBID can affect inflammatory cytokine secretion, cartilage and synovium fibrosis, synovial hyperplasia via multiple signaling pathways, thereby exacerbating osteoarthritis. Based on the existing research of HYBID in osteoarthritis, HYBID can break the metabolic balance of HA in joints through the degradation ability independent of HYALs/CD44 system and furthermore affect cartilage structure and mechanotransduction of chondrocytes. In particular, in addition to HYBID itself being able to trigger some signaling pathways, we believe that low-molecular-weight hyaluronan produced by excess degradation can also stimulate some disease-promoting signaling pathways by replacing high-molecular-weight hyaluronan in joints. The specific role of HYBID in osteoarthritis is gradually revealed, and the discovery of HYBID raises the new way to treat osteoarthritis. In this review, the expression and basic functions of HYBID in joints were summarized, and reveal potential role of HYBID as a key target in treatment for osteoarthritis.

A novel nanoparticle system targeting damaged mitochondria for the treatment of Parkinson's disease

Mitochondrial damage is one of the primary causes of neuronal cell death in Parkinson's disease (PD). In PD patients, the mitochondrial damage can be repaired or irreversible. Therefore, mitochondrial damage repair becomes a promising strategy for PD treatment. In this research, hyaluronic acid nanoparticles (HA-NPs) of different molecular weights are used to protect the mitochondria and salvage the mild and limited damage in mitochondria. The HA-NPs with 2190 k Dalton (kDa) HA can improve the mitochondrial function of SH-SY5Y cells and PTEN induced putative kinase 1 (PINK1) knockout mouse embryo fibroblast (MEF) cells. In cases of irreversible damage, NPs with ubiquitin specific peptidase 30 (USP30) siRNA are used to promote mitophagy. Meanwhile, by adding PINK1 antibodies, the NPs can selectively target the irreversibly damaged mitochondria, preventing the excessive clearance of healthy mitochondria.

Intra-articular Injection of Type I Atelocollagen to Alleviate Knee Pain: A Double-Blind, Randomized Controlled Trial

OBJECTIVE

Collagen disruption is one of the underlying causes of knee pain in patients with osteoarthritis and/or diverse cartilage defects. Atelocollagen is a type of collagen that lacks telopeptides and thus has reduced antigenicity. The intra-articular injection of type I atelocollagen supplements collagen levels in the disrupted articular cartilage. This randomized controlled trial evaluated the effects of the intra-articular injection of atelocollagen for the management of knee pain.

DESIGN

Two hundred patients with osteoarthritis, chondromalacia, or other cartilage defects were randomly assigned to receive a 3-mL intra-articular injection of atelocollagen (BioCollagen group) or saline (Placebo group). Clinical improvement was evaluated over a 24-week period using the 100-mm visual analogue scale (VAS), the Western Ontario and McMaster University Osteoarthritis Index (WOMAC), and the 36-item Short-Form Health Survey (SF-36).

RESULTS

VAS scores were significantly better in the BioCollagen group as compared with the Placebo group at 24 weeks. More patients in the BioCollagen group reported exceeding 20% and 40% VAS improvements. The WOMAC and SF-36 scores were also significantly improved from baseline after the intra-articular injection of atelocollagen; although, the differences between the BioCollagen and Placebo groups were not significant. There were no unexpected or severe adverse events reported for either group.

CONCLUSIONS

The results show that an intra-articular injection of atelocollagen effectively alleviates knee pain, as intended. Therefore, the intra-articular injection of atelocollagen can be considered an alternative solution to controlling knee pain due to osteoarthritis and diverse cartilage defects.

Optimization of hyaluronic acid-tyramine/silk-fibroin composite hydrogels for cartilage tissue engineering and delivery of anti-inflammatory and anabolic drugs

Injury of articular cartilage leads to an imbalance in tissue homeostasis, and due to the poor self-healing capacity of cartilage the affected tissue often exhibits osteoarthritic changes. In recent years, injectable and highly tunable composite hydrogels for cartilage tissue engineering and drug delivery have been introduced as a desirable alternative to invasive treatments. In this study, we aimed to formulate injectable hydrogels for drug delivery and cartilage tissue engineering by combining different concentrations of hyaluronic acid-tyramine (HA-Tyr) with regenerated silk-fibroin (SF) solutions. Upon enzymatic crosslinking, the gelation and mechanical properties were characterized over time. To evaluate the effect of the hydrogel compositions and properties on extracellular matrix (ECM) deposition, bovine chondrocytes were embedded in enzymatically crosslinked HA-Tyr/SF composites (in further work abbreviated as HA/SF) or HA-Tyr hydrogels. We demonstrated that all hydrogel formulations were cytocompatible and could promote the expression of cartilage matrix proteins allowing chondrocytes to produce ECM, while the most prominent chondrogenic effects were observed in hydrogels with HA20/SF80 polymeric ratios. Unconfined mechanical testing showed that the compressive modulus for HA20/SF80 chondrocyte-laden constructs was increased almost 10-fold over 28 days of culture in chondrogenic medium which confirmed the superior production of ECM in this hydrogel compared to other hydrogels in this study. Furthermore, in hydrogels loaded with anabolic and anti-inflammatory drugs, HA20/SF80 hydrogel showed the longest and the most sustained release profile over time which is desirable for the long treatment duration typically necessary for osteoarthritic joints. In conclusion, HA20/SF80 hydrogel was successfully established as a suitable injectable biomaterial for cartilage tissue engineering and drug delivery applications.

Intra-articular Injections of Hyaluronic Acid on Osteochondral Lesions of the Talus After Failed Arthroscopic Bone Marrow Stimulation

BACKGROUND

The purpose of the study was to compare clinical and functional outcomes before and after hyaluronic acid (HA) injections in patients with osteochondral lesions of the talus who experienced a failure of their primary treatment with arthroscopic microfracture surgery.

METHODS

A total of 40 patients were included in the final study. These patients had received microfracture surgery but continued to experience postoperative pain over an average of 13.0 months (range, 0-81 months) and were available for investigation with a mean follow-up for 29.1 months (SD 14.7; range 2.6-79.6 months). All patients received intra-articular injections of HA once per week for 3 weeks. We assessed clinical and functional outcomes before and after injection using the American Orthopaedic Foot & Ankle Society (AOFAS) score, Foot and Ankle Outcome Score (FAOS), Short Form Health Survey (SF-36), the visual analog scale (VAS) for pain, and the Alexander subjective scale.

RESULTS

The AOFAS score significantly increased from 50.7 ± 13.8 to 79.9 ± 13.8 and the FAOS scores for symptom, pain, daily living, and sports were significantly higher postinjection compared to preinjection (all P < .001). Similarly, the mean VAS for pain was significantly decreased after 6 weeks following injection and continued to decrease over the follow-up period; the mean VAS was significantly lower postinjection compared to preinjection at 12 months (P < .001).

CONCLUSION

Intra-articular HA injections on average significantly improved clinical and functional scores after failed primary operative treatment. HA injections may provide an alternative to secondary operative treatment and provide better clinical outcomes than other conservative treatments.

LEVEL OF EVIDENCE

Level II, prospective observational cohort study.

Hyaluronan in experimental injured/inflamed cartilage: In vivo studies

Joint disease is characterized by an imbalance between the synthesis and degradation of articular cartilage and subchondral bone accompanied by capsular fibrosis, osteophyte formation and varying degrees of inflammation of the synovial membrane. Many animal models have been developed to study arthritis and osteoarthritis that enable experimental conditions, diet and environmental risk factors to be carefully controlled. Animal-based studies have demonstrated the positive effects of exogenous HA on the preservation of joint cartilage in different models of arthritis and osteoarthritis. Although many promising effects of exogenous HA have been reported, there remains uncertainty as to its effectiveness in reversing cartilage injury and other manifestations of joint diseases because of difficulties in interpreting and unifying the results of these studies. A review of the literature of the last decade was conducted to report the results and to determine what we have learned from animal models in relation to joint inflammation induced by experimental models and HA treatment.

Different doses of strontium ranelate and mechanical vibration modulate distinct responses in the articular cartilage of ovariectomized rats

OBJECTIVE

To investigate the effects of different strontium ranelate (SrR) doses alone or in combination with low-intensity and high-frequency mechanical vibration (MV) on articular cartilage in ovariectomized rats.

DESIGN

Fifty 6-month-old female Wistar rats underwent ovariectomy (OVX) and after 3 months were divided into: control group (Control); SrR 300 mg/kg/day (SrR300); SrR 625 mg/kg/day (SrR625); MV; SrR 625 mg/kg/day plus MV (SrR625 + MV). The vehicle and the SrR were administered by gavage 7 days/week and vibration (0.6 g/60 Hz) was performed for 20 min/day, 5 days/week. Bone mineral density (BMD) and body composition were evaluated by densitometry. Changes in cartilage were assessed 90 days after treatment by histomorphometry; immunohistochemistry analysis evaluating cell death (caspase-3), tumor necrosis factor-α (TNF-α), metalloproteinase 9 (MMP-9) and type II collagen; Osteoarthritis Research Society International (OARSI) grading system and glycosaminoglycans (GAGs) analyses.

RESULTS

SrR-treated groups exhibited a lower OARSI grade, a smaller number of chondrocyte clusters, increased levels of chondroitin sulfate (CS) and decreased expression of caspase-3. Additionally, compared to all the groups, SrR300 exhibited increased levels of hyaluronic acid (HA). Vibration applied alone or in combination accelerated cartilage degradation, as demonstrated by increased OARSI grade, reduced number of chondrocytes, increased number of clusters, elevated expression of type II collagen and cell death, and was accompanied by decreased amounts of CS and HA; however, MV alone was able to reduce MMP-9.

CONCLUSIONS

SrR and vibration modulate distinct responses in cartilage. Combined treatment accelerates degeneration. In contrast, SrR treatment at 300 mg/kg/day attenuates osteoarthritis (OA) progression, improving cartilage matrix quality and preserving cell viability in ovariectomized rats.

Synergistic anabolic actions of hyaluronic acid and platelet-rich plasma on cartilage regeneration in osteoarthritis therapy

Osteoarthritis (OA) is a common disease associated with tissue inflammation, physical disability and imbalanced homeostasis in cartilage. For advanced treatments, biological approaches are currently focused on tissue regeneration and anti-inflammation. This study was undertaken to evaluate the therapeutic efficacies of hyaluronic acid (HA) and platelet-rich plasma (PRP) (HA+PRP) on OA. Articular chondrocytes were obtained from five OA patients. The optimal HA and PRP concentrations were evaluated by MTT assay. The expressions of chondrogenic and inflammatory genes were analyzed by RT-PCR. Signaling pathway was examined by immunoblotting and the expressions of OA pathology-related chemokines and cytokines was demonstrated by real-time PCR-based SuperArray. The therapeutic efficacies of HA+PRP were then demonstrated in 3D arthritic neo-cartilage and ACLT-OA model. Here we showed that HA+PRP could greatly retrieve pro-inflammatory cytokines-reduced articular chondrocytes proliferation and chondrogenic phenotypes, the mechanism of which involve the sequential activation of specific receptors CD44 and TGF-βRII, downstream mediators Smad2/3 and Erk1/2, and the chondrogenic transcription factor SOX9. The real-time PCR-based SuperArray results also indicated that OA pathology-related chemokines and cytokines could be efficiently suppressed by HA+PRP. Moreover, the cartilaginous ECM could be retrieved from inflammation-induced degradation by HA+PRP in both 2D monolayer and 3D neo-cartilage model. Finally, the intra-articular injection of HA+PRP could strongly rescue the meniscus tear and cartilage breakdown and then decrease OA-related immune cells. The combination of HA+PRP can synergistically promote cartilage regeneration and inhibit OA inflammation. This study might offer an advanced and alternative OA treatment based on detailed regenerative mechanisms.

Intra-articular injection of rhFGF-18 improves the healing in microfracture treated chondral defects in an ovine model

Microfracture is a common cartilage repair procedure. Strategies to improve healing post-microfracture include the use of growth factors to enhance hyaline cartilage production. This study investigates the effect of intra-articular recombinant human fibroblastic growth factor 18 (rhFHF18) on the healing of a chondral defect treated with microfracture in an ovine model. Chondral defects (8 mm diameter) were created in the medial femoral condyle of 80 sheep (n = 16/treatment group). Defects were treated with microfracture alone or microfracture + intra-articular rhFGF-18 (administered either as one or two cycles of 3× weekly injections). Outcome measures included mechanical testing, macroscopic International Cartilage Repair Society repair score, modified O'Driscoll histology score, qualitative histology, and immunohistochemistry for types I, II, and VI collagen. In treated animals, there was a statistically significant improvement in ICRS tissue repair score and tissue infill score, in the modified O'Driscoll score between control and 1 cycle of rhFGF-18 at 6 m, and in the cartilage repair score and structural characteristic score between the control and both rhFGF-18 groups at 6 m. There was no evidence of degeneration of adjacent cartilage in the rhFGF-18 treated cartilage. The increase in hyaline cartilage-like tissue formed in the microfracture + rhFGF-18 treated groups indicates that rhFGF-18 potentiates the formation of hyaline cartilage repair following microfracture.

[Treatment of acute full-thickness chondral defects with high molecular weight hyaluronic acid; an experimental model]

PURPOSE

To evaluate the effect of 2 different protocols of intra-articular hyaluronic acid (HA, hylan G-F20) to articular cartilage regeneration in acute full-thickness chondral defects.

MATERIALS AND METHODS

Full-thickness chondral defects of 3 x 6 mm were performed into the lateral femoral condyles of New Zealand rabbits, treated with a single or three doses of HA. The animals were sacrified at 12 weeks and the regenerated tissue was evaluated by direct observation and histology with the ICRS scale. Macroscopically, in both groups treated with HA the defects were filled with irregular tissue with areas similar to hyaline cartilage and others in which depressed areas with exposed subchondral bone were observed. Histological analysis showed in both groups treated with HA a hyaline-like cartilage compared to control group. However, the score of the International Cartilage Repair Society (ICRS) scale did not show differences between the groups treated with HA.

CONCLUSION

The use of single dose or 3 doses of AH in acute chondral lesions has a limited and similar benefit in articular cartilage regeneration.

Intra-articular administration of hyaluronic acid increases the volume of the hyaline cartilage regenerated in a large osteochondral defect by implantation of a double-network gel

Implantation of PAMPS/PDMAAm double-network (DN) gel can induce hyaline cartilage regeneration in the osteochondral defect. However, it is a problem that the volume of the regenerated cartilage tissue is gradually reduced at 12 weeks. This study investigated whether intra-articular administration of hyaluronic acid (HA) increases the volume of the cartilage regenerated with the DN gel at 12 weeks. A total of 48 rabbits were used in this study. A cylindrical osteochondral defect created in the bilateral femoral trochlea was treated with DN gel (Group DN) or left without any implantation (Group C). In both Groups, we injected 1.0 mL of HA in the left knee, and 1.0 mL of saline solution in the right knee. Quantitative histological evaluations were performed at 2, 4, and 12 weeks, and PCR analysis was performed at 2 and 4 weeks after surgery. In Group DN, the proteoglycan-rich area was significantly greater in the HA-injected knees than in the saline-injected knees at 12 weeks (P = 0.0247), and expression of type 2 collagen, aggrecan, and Sox9 mRNAs was significantly greater in the HA-injected knees than in the saline-injected knees at 2 weeks (P = 0.0475, P = 0.0257, P = 0.0222, respectively). The intra-articular administration of HA significantly enhanced these gene expression at 2 weeks and significantly increased the volume of the hyaline cartilage regenerated by implantation of a DN gel at 12 weeks. This information is important to develop an additional method to increase the volume of the hyaline cartilage tissue in a potential cartilage regeneration strategy using the DN gel.

Intra-articular injections of hyaluronic acid induce positive clinical effects in knees of patients affected by haemophilic arthropathy

INTRODUCTION

Haemophilic arthropathy is the most common clinical manifestation of haemophilia, secondary to recurrent haemarthrosis and chronic synovitis, and the knee represents the main target joint. Modern bleeding prevention has significatively limited the incidence of severe arthropathy, and primary approach is usually conservative. Viscosupplementation is felt as one of the most efficient treatments for the early stages of knee haemophilic arthropathy, based on short-term follow-up studies. The aim of this prospective case series study is to assess the clinical effectiveness of intra-articular administration of hyaluronic acid in the knee, evaluating long-term results, and focusing on the necessity of further treatments after viscosupplementation.

METHODS

Twenty-seven haemophilic patients with knee arthropathy underwent at least two cycles of injections of hyaluronians between 2003 and 2009. They were evaluated with VAS, SF-36, WFH, Pettersson score, and WOMAC, with a seven-year follow-up.

RESULTS

All patients showed improvement in pain relief and functional recovery without any complications. Considering the severity of arthropathy in haemophilic patients, only a limited number of subjects (five) underwent total knee arthroplasty for persistent pain or functional limitation.

CONCLUSIONS

Viscosupplementation is a safe and effective therapeutic strategy in knee haemophilic arthropathy, with no complications, persisting good clinical results, and determining in most cases a delay of surgery.

Hylan G-F 20 maintains cartilage integrity and decreases osteophyte formation in osteoarthritis through both anabolic and anti-catabolic mechanisms

OBJECTIVE

To perform a molecular mechanism-based investigation of the chondroprotective potential of hylan G-F 20.

METHOD

The effects of hylan G-F 20 on IL-1β-induced glycosaminoglycan (GAG) depletion and matrix metalloproteinase (MMP) expression in bovine and human cartilage explants were evaluated. Three weekly intra-articular hylan G-F 20 or control injections were administered 4 weeks post-operatively to rabbits with surgically induced osteoarthritis (OA). Cartilage histopathologic scores and osteophyte size were evaluated at 1, 4, and 8 weeks post-injections. Histomorphometry and immunostaining were used to quantify cartilage area and type II collagen (Col II) intensity, and real-time polymerase chain reaction (PCR) was used to examine the mRNA levels of Col2A1, MMP-13, -16 and IL-1β at 1 week.

RESULTS

Hylan G-F 20 retained GAG in IL-1β-exposed bovine and human cartilage explants and abrogated IL-1β-mediated increases in MMP-1, -3, and -13 in human explant culture. Hylan G-F 20‒treated OA joints had significantly better cartilage integrity at 1 and 4 weeks post-treatment and significantly smaller osteophytes at 4 weeks compared with control. Col2A1 mRNA increased with hylan G-F 20 treatment, which correlated with a trend toward increased Col II immunostaining. MMP-13 and -16 mRNAs increased in OA cartilage, but were not significantly altered by hylan G-F 20. IL-1β mRNA was undetectable in cartilage and unaltered in the synovium.

CONCLUSIONS

Hylan G-F 20 improved cartilage integrity and decreased osteophyte formation in the rabbit model of OA. Our results suggest that hylan G-F 20 may stimulate cartilage repair by increasing Col II, and inhibit IL-1β-mediated matrix degradation by decreasing MMPs.

Therapeutic effects of mesenchymal stem cells and hyaluronic Acid injection on osteochondral defects in rabbits' knees

Purpose

To evaluate the treatment results of intraarticular injection according to the frequency of hyaluronic acid with mesenchymal stem cells on the osteochondral defect of rabbits' medial femoral condyles.

Materials and Methods

A 5 mm diameter and 4 mm depth osteochondral defect was made on the medial femoral condyles of 18 rabbits, divided into six groups. One week after osteochondral defect, group B was injected intraarticularly with hyaluronic acid (HA), group C with mesenchymal stem cells (MSCs), and group D, E and F with both HA and MSCs. Group E and F received second HA injection a week after. Further, group F received third HA injection in the third week.

Results

In a macroscopic evaluation, groups B (6; range, 5-8), C (6; range, 6-7), D (7; range, 6-7), E (6.5; range, 6-8) and F (7.5; range, 6-8) showed statistically significant improvements in osteochondral defect healing, compared with that of group A (4; range, 3-5) (p=0.002). In histological evaluation, groups B (11.5; range, 11-13), C (13; range, 12-18), D (16; range, 13-18), E (17.5; range, 13-20), and F (19.5; range, 12-22) showed statistically significant differences in osteochondral defect healing, compared with group A (8; range, 6-9) (p=0.006).

Conclusions

The intraarticular injections of MSCs or HA can play an effective role during the healing osteochondral defects in rabbits.

Chitosan, hyaluronan and chondroitin sulfate in tissue engineering for cartilage regeneration: a review

Injection of hyaluronan into osteoarthritic joints restores the viscoelasticity, augments the flow of joint fluid, normalizes endogenous hyaluronan synthesis, and improves joint function. Chitosan easily forms polyelectrolyte complexes with hyaluronan and chondroitin sulfate. Synergy of chitosan with hyaluronan develops enhanced performances in regenerating hyaline cartilage, typical results being structural integrity of the hyaline-like neocartilage, and reconstitution of the subchondral bone, with positive cartilage staining for collagen-II and GAG in the treated sites. Chitosan qualifies for the preparation of scaffolds intended for the regeneration of cartilage: it yields mesoporous cryogels; it provides a friendly environment for chondrocytes to propagate, produce typical ECM, and assume the convenient phenotype; it is a good carrier for growth factors; it inactivates metalloproteinases thus preventing collagen degradation; it is suitable for the induction of the chondrogenic differentiation of mesenchymal stem cells; it is a potent means for hemostasis and platelet delivery.

Analgesic control and functional outcome after knee arthroscopy: results of a randomized double-blinded trial comparing a hyaluronic acid supplement with bupivacaine

OBJECTIVE

Hyaluronic acid (HA) is a naturally occurring substance within normal synovial joints. Although its efficacy in treating osteoarthritis has been evaluated, it has not been established whether it is of benefit after routine arthroscopic procedures. We hypothesized that immediate supplementation with HA after completion of arthroscopy would result in improved short-term analgesic and functional outcomes after knee arthroscopy.

DESIGN

Double-blinded randomized controlled trial.

SETTING

Tertiary referral center.

PATIENTS

One hundred ten patients presenting for routine arthroscopic procedures were invited to participate in the study. After exclusion criteria were applied, 98 patients were randomized to receive either 10 mL of 0.5% bupivacaine or 3 mL of HA into the joint immediately after completion of surgery.

INTERVENTIONS

After completion of surgery, all patients were randomized to receive either 10 mL of 0.5% bupivacaine or 3 mL of HA into the knee joint.

MAIN OUTCOME MEASURES

Visual analogue scale (VAS) pain scores were obtained at baseline; 1, 2, and 24 hours; and 1, 2, and 6 weeks after surgery. Western Ontario and McMaster Universities (WOMAC) and Tegner-Lysholm scores were obtained at baseline and then at 1, 2, and 6 weeks after surgery.

RESULTS

Forty-nine patients received intra-articular bupivacaine and 49 received HA. There was no statistical difference in any of the outcome measures (VAS pain scores, WOMAC, and Tegner-Lysholm) at any time point between the groups overall.

CONCLUSIONS

There was no benefit of HA injection immediately at the end of knee arthroscopy in the first 6 weeks after surgery.

CLINICAL RELEVANCE

Routine use of HA at the time of knee arthroscopy cannot be recommended.

Intraarticular Hyaluronic Acid Injection after Microfracture Technique for the Management of Full-Thickness Cartilage Defects Does Not Improve the Quality of Repair Tissue

OBJECTIVE

Tissue repair that occurs after microfracture does not include hyaline-like cartilage. Therefore, other treatment modalities must be combined with microfracture to improve repair tissue quality. In this study, we combined exogenous hyaluronic acid with microfracture.

DESIGN

Thirty mature New Zealand rabbits were randomly divided into 3 groups as control, microfracture (MF), and microfracture and hyaluronic acid (MFHA). Four-millimetre full-thickness cartilage defects were created in the medial femoral condyle of each rabbit. Microfracture was performed on defects in the MF and MFHA groups. At 1 week following surgery, 1 mL of saline was injected into the knees of the control and MF groups, whereas 1 mL (15 mg/mL) hyaluronic acid was injected into the knees of the MFHA group 3 times weekly. At 6 months postsurgery, defects were evaluated according to the ICRS (International Cartilage Repair Society) and Wakitani scales.

RESULTS

According to the ICRS and Wakitani scales, the quality of repair tissue was improved in MF and MFHA groups as compared the control group (P = 0.001 and 0.001, respectively). No significant difference was observed between the MF and MFHA groups (P = 0.342).

CONCLUSIONS

According to the model in this study, no beneficial effect was obtained when HA injection was combined with microfracture in the treatment of full-thickness cartilage defects.

Injectable hyaluronic acid-tyramine hydrogels for the treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease caused by inflammation of the synovial membrane, leading in turn to articular cartilage destruction. In this work, injectable tyramine modified hyaluronic acid (HA-Tyr) hydrogels were developed for the treatment of RA. HA-Tyr conjugate was synthesized by amide bond formation between carboxyl groups of HA and amine groups of tyramine. Then, HA-Tyr hydrogels were prepared by radical crosslinking reaction using H(2)O(2) and horse-radish peroxidase. Intra-articular injection of HA-Tyr hydrogels encapsulating dexamethasone (DMT) as a model drug resulted in successful treatment of RA with reduced interlukine-6, prostaglandin E2 and four types of cytokine levels in collagen-induced arthritis animal models. Histological analysis with hematoxylin and eosin (H&E) staining also confirmed the therapeutic effect of injectable HA-Tyr hydrogels with DMT. Taken together, the injectable HA-Tyr hydrogels were thought suitable to be developed as a therapeutically effective drug carrier for the treatment of RA.

Anti-Flt1 peptide - hyaluronate conjugate for the treatment of retinal neovascularization and diabetic retinopathy

Anti-angiogenic therapeutics has been investigated extensively for the treatment of retinal and choroidal vascular diseases, and diabetic retinopathy. Anti-Flt1 peptide of GNQWFI is an antagonistic peptide for vascular endothelial growth factor receptor 1 (VEGFR1 or Flt1) inhibiting VEGFR1-mediated endothelial cell migration and tube formation. In this work, anti-Flt1 peptide (GGNQWFI) was chemically conjugated to tetra-n-butyl ammonium modified hyaluronate (HA-TBA) via amide bond formation in dimethyl sulfoxide (DMSO) using benzotriazol-1-yloxy-tris(dimethylamino)phosphonium hexafluorophosphate (BOP). The resulting HA - GGNQWFI conjugate self-assembled to form micelle-like nanoparticles in aqueous solution, as confirmed and characterized by transmission electron microscopy (TEM). According to in vitro biological activity tests, HA - GGNQWFI conjugate exhibited a dose-dependent inhibition effect on the binding of Flt1-Fc to VEGF(165) coated on the well. Furthermore, anti-Flt1 peptide - HA conjugate effectively inhibited retinal choroidal neovascularization (CNV) in laser induced CNV model rats. The retinal vascular permeability and the deformation of retinal vascular structure were also significantly reduced in diabetic retinopathy model rats after treatment with anti-Flt1 peptide - HA conjugate. Pharmacokinetic analysis confirmed the increased mean residence time of anti-Flt1 peptide after conjugation to HA longer than 2 weeks.

Efficacy and safety of hylan G-F 20 for symptomatic glenohumeral osteoarthritis: a prospective, pilot study

OBJECTIVE

To determine the safety and efficacy of 2 intra-articular, fluoroscopically guided hylan G-F 20 injections for painful glenohumeral osteoarthritis.

DESIGN

This study was a prospective open-label pilot investigation with both U.S. Food and Drug Administration and institutional review board approval.

SETTING

Private, outpatient practice within a tertiary care, university medical school.

PARTICIPANTS

Thirty-six subjects with moderate to severe glenohumeral osteoarthritis, with pain (visual analog scale [VAS] 40 mm or greater) despite following a 3-month standard, nonsurgical treatment program.

INTERVENTIONS

Two injections of 2 mL hylan G-F 20, under fluoroscopic guidance confirmed by arthrography, 2 weeks apart. No new treatments were allowed during the course of the study. Analgesics were discontinued 24 hours before visits.

MAIN OUTCOME MEASUREMENTS

Data collected were radiographs; rotator cuff integrity as determined with magnetic resonance imaging; VAS for pain at rest, at night, and with activity; and shoulder-related quality of life (Western Ontario Rotator Cuff Index [WORC]). Subjects were re-evaluated after each injection and at 6 weeks, 3 months, and 6 months. Changes from baseline for VAS and WORC were recorded in Excel and analyzed using SPSS. Intent-to-treat analysis was performed. The type and severity of adverse events were recorded.

RESULTS

Mean VAS at baseline was 63 mm (SD 14.5). Clinically (>or=20% improvement) and statistically significant improvements (P < .001) in VAS pain were seen at 6 weeks, 3 months, and 6 months. Mean improvement in WORC at 6 months was 16.5 (P < .01), with most gains in "lifestyle" and "emotion" questions. Age, gender, body mass index, and rotator cuff pathology did not correlate with response. Three subjects described heightened pain for a few days after injections. Three subjects reported greater pain at 6 months and were unsatisfied. Four experienced no effect of treatment. There were no inflammatory reactions.

CONCLUSION

Two hylan G-F 20 injections improved pain and function, and should be considered as part of a multimodal shoulder osteoarthritis treatment program.

Effects of hyaluronic acid on mitochondrial function and mitochondria-driven apoptosis following oxidative stress in human chondrocytes

Hyaluronic acid is widely used in the treatment of osteoarthritis and exerts significant chondroprotective effects. The exact mechanisms of its chondroprotective action are not yet fully elucidated. Human articular chondrocytes actively produce reactive oxygen and nitrogen species capable of causing cellular dysfunction and death. A growing body of evidence indicates that mitochondrial dysfunction and mitochondrial DNA damage play a causal role in disorders linked to excessive generation of oxygen free radicals. We hypothesized that the chondroprotective effects of hyaluronic acid on oxidatively stressed chondrocytes are due to preservation of mitochondrial function and amelioration of mitochondria-driven apoptosis. When primary human chondrocyte cultures were exposed to reactive oxygen or nitrogen species generators, mitochondrial DNA damage along with mitochondrial dysfunction and mitochondria-driven apoptosis accumulated as a consequence. In addition, cytokine-treated primary human chondrocytes showed increased levels of mitochondrial DNA damage. Pretreatment of chondrocytes with hyaluronic acid caused a decrease of mitochondrial DNA damage, enhanced mitochondrial DNA repair capacity and cell viability, preservation of ATP levels, and amelioration of apoptosis. The results of these studies demonstrate that enhanced chondrocyte survival and improved mitochondrial function under conditions of oxidative injury are probably important therapeutic mechanisms for the actions of hyaluronic acid in osteoarthritis.

The efficacy of intra-articular hyaluronan injection after the microfracture technique for the treatment of articular cartilage lesions

BACKGROUND

Although the exact mechanism of action has yet to be elucidated, recent animal studies have demonstrated chondroprotective and anti-inflammatory properties of hyaluronic acid viscosupplementation.

HYPOTHESIS

Intra-articular hyaluronic acid after microfracture improves the quality of the repair leading to a more hyaline-like repair tissue with better defect fill and adjacent area integration.

STUDY DESIGN

Controlled laboratory study.

METHODS

Full-thickness cartilage defects were created in the weightbearing area of the medial femoral condyle in 36 female New Zealand White rabbits. The defects were then treated with surgical microfracture. Eighteen rabbits formed the 3-month cohort and the other 18 formed the 6-month cohort. Within each cohort, 6 rabbits were randomly assigned to receive 3 weekly injections of hyaluronic acid (group A), 5 weekly injections (group B), or control injections of normal saline (group C). At 3 and 6 months postmicrofracture, the animals were sacrificed and the operative knee harvested. Repair tissue was assessed blinded- both grossly, using a modified component of the International Cartilage Repair Society (ICRS) Cartilage Repair Assessment scoring scale, and histologically, using the modified O'Driscoll histological cartilage scoring system. Comparisons were made with respect to gross and histologic findings between treatment groups at each time point. Effects of each treatment type were also evaluated longitudinally by comparing the 3-month results with the 6-month results. Statistical analysis was performed using unpaired Student t tests with significance defined as P < .05.

RESULTS

At 3 months, gross and histologic evaluation of the repair tissue demonstrated that the 3-injection group had significantly better fill of the defects and more normal appearing, hyaline-like tissue than controls (a mean ICRS score of 1.92 vs 1.26; P < .05 and a mean modified O'Driscoll score of 10.3 vs 7.6; P < .02). Specimens treated with 5 weekly injections were not significantly improved compared with controls. At 6 months, the mean gross appearance and histologic scores between the 3 specimen cohorts were not significantly different. However, examination of the entire operative knee demonstrated a significantly greater extent of degenerative changes (synovial inflammation and osteophyte formation) in the control group than in both hyaluronic acid treatment groups (P < .05).

CONCLUSION

Supplementing the microfracture technique with 3 weekly injections of intra-articular hyaluronic acid had a positive effect on the repair tissue that formed within the chondral defect at the early follow-up time point. This improvement was not found for the 3-injection group at 6 months or for the 5-injection group at either time point. Additionally, hyaluronic acid supplementation had a possible chondroprotective and anti-inflammatory effect, limiting the development of degenerative changes within the knee joint.

CLINICAL RELEVANCE

The adjunctive use of hyaluronic acid appears to hold promise in the treatment of chondral injuries and warrants further investigation.