New treatments for osteoarthritis. Curr Opin Rheumatol. 2013;25:310-316. [PMID: 23425965 DOI: 10.1097/bor.0b013e32835f69b4]

The Effect of NSAID Use on Dextrose Prolotherapy in Patients With Knee Osteoarthritis: A Prospective Case Series

Objective

The objective was to determine whether oral non-steroidal anti-inflammatory drugs (NSAIDs) affect the efficacy of dextrose prolotherapy (DPT) in patients with knee osteoarthritis, and if the combination of these treatments is safe and well-tolerated.

Methods

Five patients with symptomatic knee osteoarthritis were included in this prospective case series. Participants underwent a series of three DPT injections at four-week intervals in their symptomatic knee(s) and were immediately prescribed a seven-day course of Ibuprofen after each injection. The main outcome measures included changes in the Knee Injury in Osteoarthritis (KOOS) questionnaire subscales (pain, symptoms, quality of life, sports and recreation function, and activities of daily living) and the Numeric Pain Rating Scale (NPRS).

Results

There was a statistically significant improvement in the KOOS subscales of pain (P < 0.0001), Symptoms (P = 0.01), and Quality of Life (P = 0.001) after 12 weeks. The KOOS subscales for Sports and Recreation function (P = 0.06) and Activities of Daily Living (P = 0.10) showed numerical improvement over time that fell short of statistical significance. There was a statistically significant improvement in the NPRS scores compared with baseline NPRS scores after 12 weeks (P < 0.0001). In addition, NPRS scores were significantly lower at one-week follow-up after each DPT injection (P = 0.01); (P = 0.025); (P < 0.0001). There were no reported adverse events.

Conclusions

Concomitant use of NSAIDS with dextrose prolotherapy injections is safe and well-tolerated with no adverse events and results in improvements in pain, symptoms, and overall quality of life associated with chronic knee OA. Controlled trials of this treatment are warranted.

A carrier-free nano-drug assembled via π-π stacking interaction for the treatment of osteoarthritis

Osteoarthritis (OA) is considered to be the most common joint disorder. Exogenous drug intervention is one of the effective means for OA treatment. Clinical applications of numerous drugs are restricted owing to the short retention as well as rapid clearance in the joint cavity. A wide variety of carrier-based nanodrugs have been developed, but additional carriers may bring unexpected side effects or even toxicity. Herein, by exploiting the spontaneous fluorescence of Curcumin, we designed a new carrier-free self-assembly nanomedicine Curcumin (Cur)/icariin (ICA) nanoparticles with adjustable particle size, which is composed of two small-molecule natural drugs assembled via π-π stacking interaction. Experimental results revealed that Cur/ICA NPs endowed with little cytotoxicity, high cellular uptake and sustained drug release, could inhibit secretion of inflammatory cytokines and reduce cartilage degeneration. Moreover, both the in vitro and in vivo experiments showed the NPs exerted superior synergism effects in anti-inflammatory and cartilage protection than either Cur or ICA alone, and self-monitored its retention by autofluorescence. Thus, the new self-assembly nano-drug combining Cur and ICA represents a new strategy for the treatment of osteoarthritis.

Diosmetin inhibits subchondral bone loss and indirectly protects cartilage in a surgically-induced osteoarthritis mouse model

Osteoarthritis (OA) is a common degenerative disease characterized by articular cartilage destruction, subchondral bone remodeling, ectopic osteophyte formation and synovitis. It is now recognized that the integrity of the underlying subchondral bone is crucial for the maintenance of the overlying articular cartilage. Therapeutic agents that can prevent subchondral bone loss are demonstrate potential in the prevention and treatment of OA. Diosmetin (DIOS; 3',5,7 -trihydroxy-4'-methoxy flavone), a natural flavonoid, has been shown to exert anti-oxidative, anti-inflammatory, anti-apoptotic and anticancer properties. In this study, we found that diosmetin suppressed the DMM-induced subchondral bone loss and reduced subsequent cartilage degradation in vivo. Cellular-based assays showed that diosmetin inhibited RANKL-induced osteoclast formation and bone resorption,but did not affect IL-1β-induced chondrocyte hypertrophy. Biochemical analyses demonstrated that the anti-osteoclastic effect of diosmetin was at least in part due to the suppression of RANKL-induced activation of the ERK, p38, and JNK MAPK signaling pathways. Collectively, our results show that diosmetin have potential as a therapeutic agent the treatment of abnormal subchondral bone loss and cartilage degradation associated with the onset of OA.

Efficacy of Oxygen-Ozone Therapy and Platelet-Rich Plasma for the Treatment of Knee Osteoarthritis: A Meta-analysis and Systematic Review

CONTEXT

This systematic review and meta-analysis evaluated the effect of the intra-articular injection of platelet-rich plasma (PRP) and oxygen-ozone therapy and provided an evidence-based methodology to treat KOA.

METHOD

Databases, including Cochrane Library, PubMed, and EMBASE, were searched. The retrieval period was before 2021. Two reviewers performed the process of screening and data extraction. Mean differences were calculated [95% confidence interval (CI)] with an inverse-variance method and fixed effect model. Meta-analysis was performed using the latest version of STATA version 16.

RESULTS

A total of 12 studies out of 769 articles were evaluated. The mean difference of visual analog scale score between ozone and control groups in the first month after injection was -0.02 (MD, -0.02; 95% CI: -0.32, 0.28; P < 0.05). Mean differences of WOMAC pain, stiffness, and physical function score between baseline and after PRP were -3.53 (MD: -3.53; 95% CI: -4.04, -3.02; P = 0.00), -0.60 (MD: -0.60; 95% CI: -4.0 - 0.864, -0.34; P = 0.00), and -5.96 (MD: -5.96; 95% CI: -7.83, -4.09; P = 0.00).

CONCLUSIONS

Our results showed that to treat knee osteoarthritis, using PRP for a longer period of 6 - 12 months after the intervention shows better clinical results, while oxygen-ozone therapy has short-term results.

An Updated Systematic Review and Meta-analysis of Duloxetine for Knee Osteoarthritis Pain

OBJECTIVE

We conducted the updated systematic review and meta-analysis of the best available quantitative and qualitative evidence to evaluate the effects and safety of duloxetine for the treatment of knee osteoarthritis (OA) pain.

METHODS

A comprehensive literature search used 3 English and 4 Chinese biomedical databases from inception through July 10, 2020. We included randomized controlled trials of duloxetine with intervention duration of 2 weeks or longer for knee OA. The primary outcome was pain intensity measured by Brief Pain Inventory and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscale. Secondary outcome measurements included 36-Item Short Form Health Survey, Patient's Global Impression of Improvement, Clinical Global Impressions of Severity, and adverse events (AEs). The quality of all included studies was evaluated using the Cochrane risk-of-bias criteria. The review was registered in the PROSPERO (CRD 42020194072).

RESULTS

Six studies totaling 2059 patients met the eligibility criteria. Duloxetine had significant reductions in Brief Pain Inventory 24 hours average pain (mean difference [MD]=-0.74; 95% confidence interval [CI], -0.92 to -0.57; P<0.00001; I2=13%; 5 trials; 1695 patients); patient general activity (MD=-0.76; 95% CI, -0.96 to -0.56; P<0.00001; I2=0%; 5 trials; 1694 patients) WOMAC physical function subscale (MD=-4.22; 95% CI, -5.14 to -3.30; P<0.00001; I2=26%; 5 trials; 1986 patients); Patient's Global Impression of Improvement (MD=-0.48; 95% CI, -0.58 to -0.37; P<0.00001; I2=29%; 5 trials; 1741 patients); and Clinical Global Impressions of Severity (MD=-0.34; 95% CI, -0.44 to -0.24; P<0.00001; I2=0%; 4 trials; 1178 patients) compared with placebo control. However, no difference on WOMAC pain subscale (standard mean difference=-1.68; 95% CI, -3.45 to 0.08; P=0.06; I2=100%; 3 trials; 1104 patients) and in serious AEs (risk ratio=0.92; 95% CI, 0.40-2.11; P=0.84; I2=0%; 5 trials; 1762 patients) between duloxetine and placebo. Furthermore, duloxetine failed to show superior effects for improving the life quality and demonstrated more treatment-emergent AEs.

CONCLUSION

Duloxetine may be an effective treatment option for knee OA patients but further rigorously designed and well-controlled randomized trials are warranted.

CD226 Is Required to Maintain Megakaryocytes/Platelets Homeostasis in the Treatment of Knee Osteoarthritis With Platelet-Rich Plasma in Mice

Platelet-rich plasma (PRP) is a platelet-based application used to treat osteoarthritis (OA) clinically. The co-stimulatory molecule CD226 is expressed in T cells, NK cells, and also platelets. However, exact effects of CD226 on platelets and whether its expression level influences PRP efficacy are largely unknown. Here, CD226^fl/flPF4-Cre mice were obtained from mating CD226 ^fl/fl mice with PF4-Cre mice. Blood samples and washed platelets were collected from the mice eyeballs to undergo routine blood tests and transmission electron microscopy. Differentially expressed proteins were detected by iTRAQ-based proteomics analysis. Animal OA models were established through surgical destabilization of the medial meniscus (DMM) for C57BL/6 wildtype mice, followed by PRP injection to evaluate the effects of platelet CD226 on PRP efficacy. The results showed that deletion of platelet CD226 increased the number of megakaryocytes (MKs) in bone marrow (BM) but reduced MKs in spleen, combined with significantly decreased platelet amounts, α-granule secretion, and reduced immature platelets; indicating that absence of platelet CD226 may disrupt MK/platelet homeostasis and arrested platelet release from MKs. Sequencing analysis showed abnormal ribosomal functions and much downregulated proteins in the absence of platelet CD226. Autophagy-related proteins were also reduced in the CD226-absent MKs/platelets. Moreover, deletion of platelet CD226 diminished the protective effects of PRP on DMM-induced cartilage lesions in mice, and PDGF restored it. Therefore, deficiency of platelet CD226 inhibited platelet maturation, secretion, and normal ribosomal functions, which may lead to depressed PRP efficacy on OA, suggesting that CD226 is required to regulate platelet growth, functions, and its application.

An Anti-Inflammatory Composition of Boswellia serrata Resin Extracts Alleviates Pain and Protects Cartilage in Monoiodoacetate-Induced Osteoarthritis in Rats

The boswellic acids, the active compounds in Boswellia serrata gum resin extract, are potent anti-inflammatory agents and are specific nonredox inhibitors of 5-Lipoxygenase (5-LOX). Here, we present the anti-osteoarthritis (OA) efficacy of LI13019F1 (also known as Serratrin®), a unique composition containing the acidic and nonacidic fractions of B. serrata gum resin. This composition strongly inhibited 5-LOX activity with the half-maximal inhibitory concentration (IC₅₀) of 43.35 ± 4.90 μg/mL. Also, LI13019F1 strongly inhibited the leukotriene B₄ (IC₅₀, 7.80 ± 2.40 μg/mL) and prostaglandin E₂ (IC₅₀, 6.19 ± 0.52 μg/mL) productions in human blood-derived cells. Besides, LI13019F1 reduced TNF-α production with the IC₅₀ of 12.38 ± 0.423 μg/mL. On average, 1, 2.5, and 5 μg/mL doses of LI13019F1 protected 34.62, 47.66, and 62.29% SW1353 human chondrosarcoma cells from IL-1β induced SOX-9 depletion, respectively. Further, a 28-day preclinical proof-of-concept study evaluated the pain relief efficacy of LI13019F1 in monoiodoacetate- (MIA-) induced Sprague-Dawley rats. At the end of the study, 150 and 300 mg/kg doses of LI13019F1 supplemented rats showed significant improvements (55.17 ± 5.81 g (p < 0.05), and 66.22 ± 6.30 g (p < 0.05), respectively, vs. MIA: 31.22 ± 7.15 g) in body-weight-bearing capacities. Concurrently, LI13019F1-150 and LI13019F1-300 rats substantially (p < 0.05) increased the threshold of pain sensitivity to pressure (26.98 ± 2.36 and 28.06 ± 2.72-gram force, respectively; vs. 18.63 ± 5.82 in MIA) and increased (p < 0.05) the latent time to withdraw the paw after a thermal stimulus (23.61 ± 2.73 and 28.18 ± 1.90 sec, respectively; vs. 16.56 ± 1.22 sec. in MIA). Besides, the histological observations on Safranin-O green stained articular cartilage revealed that LI13019F1 also prevented the MIA-induced structural damage of the cartilage and reduced the loss of the extracellular matrix (ECM) components in the experimental rats. In conclusion, the present observations suggest that LI13019F1, a new composition of B. serrata gum resin extracts, reduces pain and protects articular cartilage from the damaging action of MIA in a rodent model.

A novel diclofenac-hydrogel conjugate system for intraarticular sustained release: Development of 2-pyridylamino-substituted 1-phenylethanol (PAPE) and its derivatives as tunable traceless linkers

A local sustained-release drug delivery system, or depot, for intra-articular injection offers the opportunity to release a therapeutic agent directly to the joint with limited need for reinjection. A successful system would provide more consistent efficacy and minimize systemic side effects. In this paper, we explore the potential use of diclofenac, a non-steroidal anti-inflammatory drug, for use in a polymer-conjugate depot system. During the course of our exploration it was determined that "conventional ester" conjugates of diclofenac were not appropriate as upon incubation in buffer (pH 7.4) or in bovine synovial fluid, a considerable amount of undesired diclofenac-lactam was released. Thus we developed a novel linker system for diclofenac in order to minimize the production of the lactam. This new linker enables a diclofenac conjugate system with tunable release rates and minimizes the production of undesired lactam side-products.

Effects and safety of the combination of platelet-rich plasma (PRP) and hyaluronic acid (HA) in the treatment of knee osteoarthritis: a systematic review and meta-analysis

BACKGROUND

Studies have shown that the combined application of hyaluronic acid (HA) and platelet-rich plasma (PRP) can repair degenerated cartilage and delay the progression of knee osteoarthritis (KOA). The purpose of this study was to explore the efficacy and safety of the intra-articular injection of PRP combined with HA compared with the intra-articular injection of PRP or HA alone in the treatment of KOA.

METHODS

The PubMed, Cochrane Library, EMBASE and China National Knowledge Infrastructure (CNKI) databases were searched from inception to December 2019. Randomized controlled trials and cohort studies of PRP combined with HA for KOA were included. Two orthopaedic surgeons conducted the literature retrieval and extracted the data. Outcome indicators included the Western Ontario and McMaster Universities Arthritis Index (WOMAC), the Lequesne Index, the visual analogue scale (VAS) for pain, and adverse events (AEs). Review Manager 5.3 was used to calculate the relative risk (RR) or standardized mean difference (SMD) of the pooled data. STATA 14.0 was used for quantitative publication bias evaluation.

RESULTS

Seven studies (5 randomized controlled trials, 2 cohort studies) with a total of 941 patients were included. In the VAS comparison after 6 months of follow-up, PRP combined with HA was more likely to reduce knee pain than PRP alone (SMD: - 0.31; 95% confidence interval (CI): - 0.55 to - 0.06; P = 0.01 < 0.05). PRP combined with HA for KOA achieved better improvements in the WOMAC Function Score (SMD: -0.32; 95% CI: - 0.54 to - 0.10; P < 0.05) and WOMAC Total Score (SMD: -0.42; 95% CI: - 0.67 to - 0.17; P < 0.05) at the 12-month follow-up than did the application of PRP alone. In a comparison of Lequesne Index scores at the 6-month follow-up, PRP combined with HA improved knee pain scores more than PRP alone (SMD: -0.42; 95% CI: - 0.67 to - 0.17; P < 0.05). In terms of AEs, PRP combined with HA was not significantly different from PRP or HA alone (P > 0.05).

CONCLUSIONS

Compared with intra-articular injection of PRP alone, that of PRP combined with HA can improve the WOMAC Function Scores, WOMAC Total Score, 6-month follow-up VAS ratings, and Lequesne Index scores. However, in terms of the incidence of AEs, PRP combined with HA is not significantly different from PRP or HA alone.

Oral Administration of Strontium Gluconate Effectively Reduces Articular Cartilage Degeneration Through Enhanced Anabolic Activity of Chondrocytes and Chondrogenetic Differentiation of Mesenchymal Stromal Cells

Osteoarthritis (OA), a common degenerative disease affecting articular cartilage, is caused by multiple factors, and currently, there are few approaches to effectively delay its progression. This study aimed to evaluate whether a strontium compound (in the form of strontium gluconate, Glu-Sr) could reduce OA pathology severity in osteoarthritic rat models by directly targeting chondrocytes, including catabolic/anabolic activities and/or chondrogenic differentiation. Glu-Sr was administered to OA rats by oral gavage beginning during OA induction and continuing for 8 weeks. Glu-Sr treatment was found to significantly reduce cartilage degeneration and delay OA progression. Further examination showed that collagen II, Sox9, and aggrecan (ACAN) genes were up-regulated whereas IL-1β was down-regulated in chondrocytes isolated from Glu-Sr-treated rats. Glu-Sr also antagonized the catabolic effects of IL-1β on chondrocytes. Furthermore, Glu-Sr was shown to promote the chondrogenic differentiation of bone marrow mesenchymal stem cells (BMMSCs), possibly through promoting chondrogenic gene expression, including CTGF and FGF1, as revealed by RNA-sequencing (RNA-seq). These results suggest that systemic administration of Glu-Sr may be useful in prophylactic and therapeutic treatment of chronic cartilage degradation through affecting multiple steps from chondrogenic differentiation of progenitors to matrix formation in mature chondrocytes.

Biologic Therapies for the Treatment of Knee Osteoarthritis

BACKGROUND

The use of biologic therapies for the management of knee osteoarthritis has increased, despite insufficient evidence of efficacy. Our aim was to complete a systematic review and analysis of reports utilizing the highest level-of-evidence evaluating: (1) platelet-rich plasma injections (PRPs); (2) bone marrow-derived mesenchymal stem cells (BMSCs); (3) adipose-derived mesenchymal stem cells (ADSCs); and (4) amnion-derived mesenchymal stem cells (AMSCs).

METHODS

PubMed, Embase, and Cochrane Library databases were queried for studies evaluating PRP injections, BMSCs, ADSCs, and AMSCs in patients with knee osteoarthritis. Of 1009 studies identified within the last 5 years, 123 met inclusion criteria. A comprehensive analysis of all levels-of-evidence was performed, as well as separate analysis on level-of-evidence I studies. Level-of-evidence was determined by the American Academy of Orthopedic Surgeons classification system.

RESULTS

Although the majority of PRP reports demonstrated improvements in pain and/or function, others revealed no substantial improvements. Similar findings were noted for BMSCs, ADSCs, and AMSCs. Assessments of BMSC studies yielded majority with positive clinical results, although short-lived. Studies on ADSCs revealed improved clinical outcomes, but equivocal radiographic outcomes. Studies evaluating AMSCs demonstrated improvements in pain and function, and decreased radiographic evidence of osteoarthritis.

CONCLUSION

Despite some promising early results for PRP, BMSC, ADSC, and AMSC therapies, the majority of level-of-evidence I studies have multiple problems: small sample sizes, potentially inappropriate control cohorts, short-term follow-up, and so on. Despite the limitations, there still appears to be evidence justifying their use for knee osteoarthritis management. More high-level, larger human studies utilizing standardized protocols are needed.

Translation, cross-cultural adaptation and validation of the Osteoarthritis Quality of Life (OAQoL) questionnaire for use in Portugal

Osteoarthritis (OA) is the most prevalent rheumatic disease and is a leading cause of decreased quality of life (QoL). The OA Quality of Life questionnaire (OAQoL) is an OA-specific patient-reported outcome measures. The aim of this study was to translate and validate the original UK English version of the Osteoarthritis Quality of Life (OAQoL) questionnaire into European Portuguese. The translation of the questionnaire was carried out according to a dual panel methodology (bilingual panel followed by lay panel). This was followed by cognitive debriefing interviews (CDIs) with OA patients to assess comprehension and relevance of the translated questionnaire. Finally, a validation survey was conducted to assess its psychometric properties. The Portuguese OAQoL, a comparator scale (the Nottingham Health Profile-NHP) as well as questions relating to demographic and disease information were administered to OA patients. A sub-sample of patients also completed the Portuguese OAQoL two weeks later, to assess test-retest reliability. The internal consistency, construct validity and known group validity (according to perceived OA severity) of the scale was also assessed. Both the bilingual and lay panels consisted of five individuals and no major difficulties relating to the translation process were identified. A total of ten patients with OA participated in the CDIs. The mean time to complete the questionnaire was 5 min. These interviews revealed that the Portuguese version of the OAQoL was clear, relevant and easy to complete. Finally, 53 OA patients (44 females; mean age of 67.6 years) completed the validation survey. Cronbach's alpha coefficient was 0.87, demonstrating high internal consistency. Test-retest reliability, assessed by Spearman's rank correlation coefficient, was 0.86. Moderate correlations were found with the majority of the NHP sections, providing evidence of construct validity. Significant differences in OAQoL scores were found between patients who differed according to their perceived OA severity, providing evidence of known group validity. The Portuguese version of the OAQoL is a valid and reliable questionnaire that can be used to assess QoL in OA, both in clinical practice and for research purposes.

Investigational drugs for the treatment of osteoarthritis, an update on recent developments

INTRODUCTION

Osteoarthritis (OA) is the leading cause of pain, loss of function, and disability among elderly, with the knee the most affected joint. It is a heterogeneous condition characterized by complex and multifactorial etiologies which contribute to the broad variation in symptoms presentation and treatment responses that OA patients present. This poses a challenge for the development of effective treatment on OA.

AREAS COVERED

This review will discuss recent development of agents for the treatment of OA, updating our previous narrative review published in 2015. They include drugs for controlling local and systemic inflammation, regulating articular cartilage, targeting subchondral bone, and relieving pain.

EXPERT OPINION

Although new OA drugs such as monoclonal antibodies have shown marked effects and favorable tolerance, current treatment options for OA remain limited. The authors believe there is no miracle drug that can be used for all OA patients'; treatment and disease stage is crucial for the effectiveness of drugs. Therefore, early diagnosis, phenotyping OA patients and precise therapy would expedite the development of investigational drugs targeting at symptoms and disease progression of OA.

What is new in pain modification in osteoarthritis?

There is a big need for the development of novel therapies for the safe management of chronic pain associated with OA. Here we reviewed PubMed (2015 onward) and ClinicalTrials.gov for ongoing and recently completed trials where pain in OA is the primary outcome measure. Three broad categories were identified: biological therapies, small molecules and cryoneurolysis. The most promising new strategy is blockade of nerve growth factor with antibodies. Two anti-nerve growth factor antibodies, tanuzemab and fasinumab, are in active development after the 2010 hold on trials was lifted in 2015. In addition, several active clinical trials are testing distinct mechanism-based interventions, including cytokine inhibition, selective μ, δ or κ opioid receptor agonists, zoledronate and intra-articular capsaicin. In addition to pharmacological approaches, cryoneurolytic strategies that directly target peripheral nerves may play a role in OA pain management, but efficacy profiles and long-term effects of such treatments need more study. Clearly, the therapeutic landscape for OA pain is rapidly expanding. Since symptomatic OA is a heterogeneous disease, the challenge will be to identify patients that will benefit the most from specific approaches.

Assessing patterns of T2/T1rho change in grade 1 cartilage lesions of the distal femur using an angle/layer dependent approach

PURPOSE

To assess changes in the patterns of T2 and T1rho values within grade 1 cartilage lesions of osteoarthritis (OA) patients compared to healthy controls.

MATERIALS AND METHODS

Twenty healthy knees and 25 OA knees were examined on a 3 T scanner. Areas of signal heterogeneity within the cartilage of the distal femur were identified using fat suppressed proton density-weighted imagines. T2 and T1rho values in each OA patient with grade 1 lesions were compared to average T2 and T1rho values of the corresponding areas in healthy subjects.

RESULTS

A total of 28 areas including grade 1 lesion were identified. Compared to normal cartilage, the majority of grade 1 cartilage lesions demonstrated either no significant change or a statistically significant increase in both T2 values (18/28, 64%) and T1rho values (23/28, 82%). Compared to T2, T1rho demonstrated a greater proportion of statistically significantly higher values in OA patients than those from the normal controls. However, T2 and T1rho values in grade 1 lesions can be decreased, or demonstrate mixed patterns compared to those in healthy cartilage.

CONCLUSION

Our results suggest that early degenerative cartilage lesions can demonstrate various patterns of T2 and T1rho changes.

The effects of injecting intra-articular platelet-rich plasma or prolotherapy on pain score and function in knee osteoarthritis

INTRODUCTION

Osteoarthritis (OA) is a chronic joint disease that usually occurs in older people and leads to pain and disabilities. OA treatment ranges from drug therapy to surgery. Drug and rehabilitation therapy are preferred over surgery, and, especially, there is a tendency toward compounds causing regenerative changes in the knee joint. In the present study, the effects of platelet-rich plasma (PRP) injection and prolotherapy (PRL) were examined on the level of pain and function of the knee joint in patients with OA.

METHODOLOGY

After fulfilling the inclusion criteria and signing the informed consent form, 42 patients with knee OA were scheduled for intra-articular injection in the present randomized, double-blind, clinical trial. Following admission to the operating pain room, the condition of the patient's knee was evaluated first via the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and, then, ultrasound-guided knee injection was done. Accordingly, patients in the PRP therapy group received 7 mL PRP solution and those in the PRL group received 7 mL 25% dextrose. Using the WOMAC, levels of pain and knee function were evaluated and recorded for each patient immediately prior to the first injection as well as at 1 month (immediately prior to the second injection), 2 months (a month after the second injection), and 6 months later. Data collected were analyzed using the SPSS v.20.

RESULTS

During the first and second months, a rapid decrease in the overall WOMAC score was observed in both groups. The overall WOMAC score increased at the sixth month, but was lower than the overall WOMAC score in the first month. Statistical analysis indicated that the overall WOMAC score significantly decreased in both groups of patients over 6 months.

CONCLUSION

Results of the present study suggested a significant decrease in the overall WOMAC score of patients who undergo either PRP therapy or PRL. This positive change in the overall WOMAC score led to an improvement in the quality of life of patients with knee OA shortly after the first injection. PRP injection is more effective than PRL in the treatment of knee OA.

An Autologous Anti-Inflammatory Protein Solution Yielded a Favorable Safety Profile and Significant Pain Relief in an Open-Label Pilot Study of Patients with Osteoarthritis

Osteoarthritis (OA) is a progressive and degenerative disease, which may result in significant pain and decreased quality of life. Recent updates in our understanding of OA have demonstrated that it is a whole joint disease that has many similarities to an unhealed wound containing inflammatory cytokines. The nSTRIDE Autologous Protein Solution (APS) Kit is a medical device under development for the treatment of OA. The APS Kit processes a patient's own blood at the point of care to contain high concentrations of anti-inflammatory cytokines and anabolic growth factors. This study assessed the safety and treatment effects of a single intra-articular injection of APS. Eleven patients were enrolled in this study. Sufficient blood could not be drawn from one patient who was subsequently withdrawn, leaving 10 patients treated. Minor adverse events (AEs) were experienced by seven subjects (63.6%). There was one serious AE (diverticulitis) unrelated to the device or procedure. One subject experienced AEs that were judged “likely” to be procedure related (arthralgia/musculoskeletal discomfort) and all resolved within 6 days of injection. All other AEs were unrelated to the device or procedure. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain scores improved significantly over time (ANOVA, p < 0.0001, 12.0 ± 1.2 preinjection, 3.3 ± 2.9 one year postinjection, and 72.5% WOMAC pain improvement). There was significant positive correlation between white blood cell concentration in APS and improvement in WOMAC pain scores.

A protocol for developing a clinical practice guideline for intra-articular injection for treating knee osteoarthritis

Introduction

Osteoarthritis (OA) is the most prevalent disorder of articulating joints in humans. As one of the steps of advanced pharmacological management, intra-articular treatment is applied in knee OA. However, there is no clinical practice guideline (CPG) involving intra-articular injection for knee OA. Here, we will develop a CPG according to a recognized methodology.

Methods and analysis

We will develop the new CPG according to the Institute of Medicine, the Appraisal of Guidelines for Research & Evaluation Ⅱ (AGREE Ⅱ), and WHO guideline handbook and make recommendations based on systematic reviews. We will establish a Guideline Working Group (including a Guideline Steering Subgroup, a Guideline Development Subgroup, and a Guideline Secretary Subgroup); formulate clinical questions in the form of Population, Intervention, Comparison, Outcomes (PICO); and complete a literature search. The consensus will be developed through evidence syntheses and the Delphi method. We will also consider patients' values or preferences, peer review results, and declaration of interests in developing CPG. The present CPG was registered on the International Practice Guidelines Registry Platform (http://www.guidelines-registry.org/), and the registration number is IPGRP-2016CN004.

Ethics and dissemination

The protocol will provide us a roadmap to systematically develop evidence-based CPG for intra-articular injection for knee OA. The work will be disseminated electronically and in print. The guideline would be the first CPG that is developed primarily by orthopedic specialists in China and strictly based on systematic methodology.

Strontium ranelate, a promising disease modifying osteoarthritis drug

INTRODUCTION

The articular cartilage and subchondral bone may have potential crosstalk in the development and progression of osteoarthritis (OA). Strontium ranelate (SrR) has the ability to dissociate the bone remodeling process and to change the balance between bone resorption and bone formation. Its effect on subchondral bone makes it a potential disease- modifying osteoarthritis drug (DMOAD) in the treatment of OA. The aim of the current review is to summarize up-to-date pharmacological and clinical data of SrR for OA treatment. Areas covered: A literature search was performed on PubMed and European Medicines Agency (EMA) website for all publications and documents related to SrR and OA. References of related studies were searched by hand. Treatment with SrR, especially at the dosage of 2 g/day, was associated with reduced radiographic knee OA progression, and with meaningful clinical improvement. It was also significantly associated with decreased MRI-assessed cartilage volume loss (CVL) and bone marrow lesions (BMLs). Expert opinion: SrR could be a promising DMOAD particularly for OA patients with bone phenotypes. The clinical efficacy and side effects of SrR for OA treatment need to be further investigated in future clinical trials before clinical application.

Efficacy of celecoxib versus ibuprofen for the treatment of patients with osteoarthritis of the knee: A randomized double-blind, non-inferiority trial

Objective

To compare the efficacy and tolerability of celecoxib and ibuprofen for the treatment of knee osteoarthritis symptoms.

Method

In this 6-week, multicentre, double-blind, non-inferiority trial, patients were randomized to 200 mg celecoxib once daily, 800 mg ibuprofen three times daily or placebo. The primary outcome was non-inferiority of celecoxib to ibuprofen in Patient’s Assessment of Arthritis Pain (scored 0–100). Secondary outcomes included the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index, Pain Satisfaction Scale, and upper gastrointestinal tolerability.

Results

A total of 388 patients were treated (celecoxib n = 153; ibuprofen n = 156; placebo n = 79). Mean difference (95% confidence interval) between celecoxib and ibuprofen in the Patient’s Assessment of Arthritis Pain was 2.76 (−3.38, 8.90). As the lower bound was greater than −10, celecoxib was non-inferior to ibuprofen. The WOMAC total score was significantly improved with celecoxib and ibuprofen, versus placebo. Patients receiving celecoxib were significantly more satisfied (versus placebo) in 10 of 11 measures on the Pain Satisfaction Scale versus three measures with ibuprofen. Upper gastrointestinal events were less frequent with celecoxib (1.3%) than ibuprofen (5.1%) or placebo (2.5%).

Conclusion

Celecoxib was well tolerated and as effective as ibuprofen for symptoms associated with knee osteoarthritis.

ClinicalTrials.gov identifier

NCT00630929

Adding Intra-Articular Growth Hormone to Platelet Rich Plasma under Ultrasound Guidance in Knee Osteoarthritis: A Comparative Double-Blind Clinical Trial

INTRODUCTION

Intra-articular injections of platelet rich plasma (PRP) for the treatment of knee osteoarthritis have been shown to reduce pain and improve joint function. The aim of this study is to examine the joint function by adding intra-articular growth hormone to platelet rich plasma. This study was performed on the individuals with knee osteoarthritis and under ultrasound guidance.

METHODS

Fifty four patients who were scheduled for ultra-sound guided intra-articular injection were enrolled in the study. The patients were randomly allocated to groups P (platelet rich plasma) and PS (platelet rich plasma and Somatropin). Group P and PS were injected with 5 mL of platelet rich plasma, and 4 IU growth hormone (Somatropin) added to platelet rich plasma, respectively. Intra-articular injection was performed in two steps; the onset of study and one month after. Knee joint function based on Western Ontario and McMaster osteoarthritis index (WOMAC) score at the baseline, 1 and 2 month later, and complications were evaluated.

RESULTS

WOMAC score in both groups has been significantly reduced after injections (P = 0.030). WOMAC score reduction in group PS in first month was significantly higher than group P, but in second month 2, the difference between two groups was not significant (P = 0.235). No complication was observed.

CONCLUSIONS

These results showed that adding growth hormone to platelet rich plasma for intra-articular injection improved function of the osteoarthritic knee joint in short period of time.

The current progress in understanding the molecular functions and mechanisms of visfatin in osteoarthritis

Osteoarthritis, (OA), also known as degenerative arthritis or degenerative joint disease, is the most common form of arthritis, affecting millions of people worldwide. It is a group of mechanical abnormalities involving degradation of the joints and occurs when the protective cartilage (articular cartilage) on the ends of bones such as the knees, hips and fingers abrades over time. It mainly affects the whole joint structure, including the articular cartilage, subchondral bone and synovial tissue. Extensive work has been done in the past decades to investigate the cellular mechanism of this disease. However, to date, it is still poorly understood, and there is no effective treatment. Recently, both in vitro and in vivo studies have confirmed adipokines play critical roles during OA development. Among these, leptin and adiponectin have been well investigated, whereas the effect of the novel adipokine, visfatin, on OA still needs to be revealed. Therefore, in this short review, we will focus on visfatin and summarize the current progress in the research on its role in OA development.

Effects of depression and inflammatory factors on chronic conditions of the wrist

Aims

Chronic conditions of the wrist may be difficult to manage because pain and psychiatric conditions are correlated with abnormal function of the hand. Additionally, intra-articular inflammatory cytokines may cause pain. We aimed to validate the measurement of inflammatory cytokines in these conditions and identify features associated with symptoms.

Patients and Methods

The study included 38 patients (18 men, 20 women, mean age 43 years) with a chronic condition of the wrist who underwent arthroscopy. Before surgery, the Self-Rating Depression Scale (SDS), Hand20 questionnaire and a visual analogue scale (VAS) for pain were used. Cytokine and chemokine levels in the synovial fluid of the wrist were measured using enzyme-linked immunosorbent assays and correlations between the levels with pain were analysed. Gene expression profiles of the synovial membranes were assessed using quantitative polymerase chain reaction.

Results

Older patients had high pre-operative Hand20 scores. One-year post-operative Hand20 and VAS scores and pre-operative VAS scores correlated with SDS scores. Post-operative VAS scores negatively correlated with the expression of nerve growth factor and SDS scores positively correlated with the expression of tumour necrosis factor-alpha and negatively correlated with the expression of tumour necrosis factor-converting enzyme.

Conclusion

There was a positive correlation between depression and chronic conditions of the wrist. Levels of some cytokines correlate with pain and depression. Additionally, cytokines may be important in the assessment and treatment of chronic conditions of the wrist and depression. Cite this article: Bone Joint J 2016;98-B:961–8.

Intra-articular treatment of knee osteoarthritis: from anti-inflammatories to products of regenerative medicine

OBJECTIVES

Knee osteoarthritis (OA) is a debilitating condition that may ultimately require total knee arthroplasty (TKA). Non-operative treatments are bracing, oral analgesics, physical therapy, and intra-articular knee injection (IAKI). The objective of this paper is to provide a systematic literature review regarding intra-articular treatment of knee OA and insight into promising new products of regenerative medicine that may eventually have a substantial effect on treatment.

METHODS

A literature search was executed using Medline, Cochrane, and Embase with keywords "knee osteoarthritis" and "injection." Specifically, 45 articles that discussed intra-articular knee injection using corticosteroids, hyaluronic acid, analgesics, local anesthetics, and newer products of regenerative medicine, such as platelet-rich plasma (PRP) and mesenchymal stem cells (MSC), were analyzed. Of these, eleven were level 1, three were level 2, twelve were level 3, two were level 4, and seventeen were level 5 evidence. Papers included animal models.

RESULTS

Local anesthetics have potential side effects and may only be effective for a few hours. Morphine and ketorolac may provide significant pain relief for 24 hours. Corticosteroids may give patients weeks to months of effective analgesia, but complications may occur, such as systemic hyperglycemia, septic arthritis, and joint degradation . Hyaluronic acid is a natural component of synovial fluid, but efficacy with respect to analgesia is controversial. Platelet-rich plasma formulations, autologous conditioned serum, autologous protein solution, and mesenchymal stem cell injections contain anti-inflammatory molecules and have been proposed to attenuate joint destruction or potentially remodel the joint.

CONCLUSIONS

Currently, knee OA treatment does not address the progressively inflammatory environment of the joint. More investigation is needed regarding products of regenerative medicine, but they may ultimately have profound implications in the way knee OA is managed.

Human genome-wide expression analysis reorients the study of inflammatory mediators and biomechanics in osteoarthritis

A major objective of this article is to examine the research implications of recently available genome-wide expression profiles of cartilage from human osteoarthritis (OA) joints. We propose that, when viewed in the light of extensive earlier work, this novel data provides a unique opportunity to reorient the design of experimental systems toward clinical relevance. Specifically, in the area of cartilage explant biology, this will require a fresh evaluation of existing paradigms, so as to optimize the choices of tissue source, cytokine/growth factor/nutrient addition, and biomechanical environment for discovery. Within this context, we firstly discuss the literature on the nature and role of potential catabolic mediators in OA pathology, including data from human OA cartilage, animal models of OA, and ex vivo studies. Secondly, due to the number and breadth of studies on IL-1β in this area, a major focus of the article is a critical analysis of the design and interpretation of cartilage studies where IL-1β has been used as a model cytokine. Thirdly, the article provides a data-driven perspective (including genome-wide analysis of clinical samples, studies on mutant mice, and clinical trials), which concludes that IL-1β should be replaced by soluble mediators such as IL-17 or TGF-β1, which are much more likely to mimic the disease in OA model systems. We also discuss the evidence that changes in early OA can be attributed to the activity of such soluble mediators, whereas late-stage disease results more from a chronic biomechanical effect on the matrix and cells of the remaining cartilage and on other local mediator-secreting cells. Lastly, an updated protocol for in vitro studies with cartilage explants and chondrocytes (including the use of specific gene expression arrays) is provided to motivate more disease-relevant studies on the interplay of cytokines, growth factors, and biomechanics on cellular behavior.

T1rho mapping of entire femoral cartilage using depth- and angle-dependent analysis

Objectives

To create and evaluate normalized T1rho profiles of the entire femoral cartilage in healthy subjects with three-dimensional (3D) angle- and depth-dependent analysis.

Methods

T1rho images of the knee from 20 healthy volunteers were acquired on a 3.0-T unit. Cartilage segmentation of the entire femur was performed slice-by-slice by a board-certified radiologist. The T1rho depth/angle-dependent profile was investigated by partitioning cartilage into superficial and deep layers, and angular segmentation in increments of 4° over the length of segmented cartilage. Average T1rho values were calculated with normalized T1rho profiles. Surface maps and 3D graphs were created.

Results

T1rho profiles have regional and depth variations, with no significant magic angle effect. Average T1rho values in the superficial layer of the femoral cartilage were higher than those in the deep layer in most locations (p < 0.05). T1rho values in the deep layer of the weight-bearing portions of the medial and lateral condyles were lower than those of the corresponding non-weight-bearing portions (p < 0.05). Surface maps and 3D graphs demonstrated that cartilage T1rho values were not homogeneous over the entire femur.

Conclusions

Normalized T1rho profiles from the entire femoral cartilage will be useful for diagnosing local or early T1rho abnormalities and osteoarthritis in clinical applications.

Key Points

• T1rho profiles are not homogeneous over the entire femur.

• There is angle- and depth-dependent variation in T1rho profiles.

• There is no influence of magic angle effect on T1rho profiles.

• Maps/graphs might be useful if several difficulties are solved.

New developments in the treatment of osteoarthritis - focus on biologic agents

Osteoarthritis (OA) is one of the most common diseases around the world. Medical, social, and financial consequences oblige clinicians, surgeons, and researchers to focus on finding the best treatment option, to eradicate and stop this degenerative joint disease, in order to avoid surgical options which in many instances are over-indicated. Noninvasive treatments, such as anti-inflammatory drugs, physiotherapy, orthotic devices, dietary supplements, have demonstrated lack of effectiveness. The possibility to perform intra-articular injections with hyaluronic acid, corticosteroids, or the newest but criticized treatment based on platelet-rich plasma (PRP) has changed the management of OA disease. The use of PRP has led to many differences in treatment since there is a lack of consensus about protocols, indications, number of doses, cost-effectiveness, and duration of the treatment. Many publications have suggested efficacy in tendon injuries, but when PRP has been indicated to treat cartilage injuries, things are more inconsistent. Some authors have reported their experience treating OA with PRP, and it seems that, if well indicated, it is an option as a supplementary therapy. Therefore, we need to understand that OA is a mechanical disease which not only produces changes in radiographs, but also affects the quality of life. Pathogenesis of OA has been well explained, providing us new knowledge and future possibilities to improve the clinical approach. From basic science to surgery, there is a great field we all need to contribute to, because the general population is aging and total joint replacements should not be the only solution for OA. So herein is an actual review of the developments for treating OA with biologics, intended to be useful for the population inside orthopedics who could be called bio-orthopedists, since OA is a molecular homeostasis disbalance between catabolism and anabolism triggered by mechanical stress.

Fetal vs adult mesenchymal stem cells achieve greater gene expression, but less osteoinduction

AIM: To investigate adenoviral transduction in mesenchymal stem cells (MSCs) and effects on stemness in vitro and function as a cell therapy in vivo.

METHODS: Bone marrow-derived adult and fetal MSC were isolated from an equine source and expanded in monolayer tissue culture. Polyethylenimine (PEI)-mediated transfection of pcDNA3-eGFP or adenoviral transduction of green fluorescent protein (GFP) was evaluated in fetal MSCs. Adenoviral-mediated transduction was chosen for subsequent experiments. All experiments were carried out at least in triplicate unless otherwise noted. Outcome assessment was obtained by flow cytometry or immunohystochemistry and included transduction efficiency, cell viability, stemness (i.e., cell proliferation, osteogenic and chondrogenic cell differentiation), and quantification of GFP expression. Fetal and adult MSCs were then transduced with an adenoviral vector containing the gene for the bone morphogenic protein 2 (BMP2). In vitro BMP2 expression was assessed by enzyme linked immunosorbent assay. In addition, MSC-mediated gene delivery of BMP2 was evaluated in vivo in an osteoinduction nude mouse quadriceps model. New bone formation was evaluated by microradiography and histology.

RESULTS: PEI provided greater transfection and viability in fetal MSCs than other commercial chemical reagents. Adenoviral transduction efficiency was superior to PEI-mediated transfection of GFP in fetal MSCs (81.3% ± 1.3% vs 35.0% ± 1.6%, P < 0.05) and was similar in adult MSCs (78.1% ± 1.9%). Adenoviral transduction provided significantly greater expression of GFP in fetal than adult MSCs (7.4 ± 0.1 vs 4.4 ± 0.3 millions of mean fluorescence intensity units, P < 0.01) as well as significantly greater in vitro BMP2 expression (0.16 pg/cell-day vs 0.10 pg/cell-day, P < 0.01). Fraction of fetal MSC GFP positive cells decreased significantly faster than adult MSCs (1.15% ± 0.05% vs 11.4% ± 2.1% GFP positive at 2 wk post-transduction, P < 0.05). Cell proliferation and osteogenic differentiation in vitro were not affected by Ad transduction in both fetal and adult MSCs, but fetal MSCs had reduced chondrogenic differentiation in vitro when compared to adult (P < 0.01). Chondrogenic differentiation was also significantly reduced in Ad-GFP transduced cells (P < 0.05). Ad-BMP2 transduced adult MSCs induced new bone formation in more thighs than Ad-BMP2 transduced fetal MSCs (83% vs 17% of the six treated thighs per group, P < 0.05) and resulted in increased femur midshaft diameter due to greater extent of periosteal new bone (1.57 ± 0.35 mm vs 1.27 ± 0.08 mm, P < 0.05).

CONCLUSION: Fetal MSCs may be genetically manipulated ex vivo with adenoviral vectors. Nonetheless, the abbreviated expression of the exogenous gene may limit their applications in vivo.

Management of Osteoarthritis with Avocado/Soybean Unsaponifiables

Osteoarthritis (OA) is a painful and life-altering disease that severely limits the daily activity of millions of Americans, and is one of the most common causes of disability in the world. With obesity on the rise and the world's population living longer, the prevalence of OA is expected to increase dramatically in the coming decades, generating burdensome socioeconomic costs. This review summarizes current pharmaceutical, non-pharmaceutical, and prospective new treatments for OA, with primary focus on the dietary supplement Avocado/Soybean Unsaponifiables (ASU). ASU modulates OA pathogenesis by inhibiting a number of molecules and pathways implicated in OA. Anticatabolic properties prevent cartilage degradation by inhibiting the release and activity of matrix metalloproteinases (MMP-2,3,13) and increasing tissue inhibitors of these catabolic enzymes (TIMP-1). ASU also inhibits fibrinolysis by stimulating the expression of plasminogen activator inhibitor (PAI-1). Anabolic properties promote cartilage repair by stimulating collagen and aggrecan synthesis via inhibition of inflammatory cytokines such as IL1, IL6, IL8, TNF, ERK, and PGE2. Chondroprotective effects are mediated by correcting growth factor abnormalities, increasing TGFβ while decreasing vascular endothelial growth factor (VEGF) in synovial fluid. ASU also inhibits cholesterol absorption and endogenous cholesterol biosynthesis, which mediate reactive oxygen species pathology in chondrocytes. At the clinical level, ASU reduces pain and stiffness while improving joint function, resulting in decreased dependence on analgesics.

Efficacy of platelet-rich plasma injections in osteoarthritis of the knee: a systematic review and meta-analysis

BACKGROUND

The effectiveness of platelet-rich plasma (PRP) injections for osteoarthritis (OA) is still controversial. We investigated the effect of PRP injections in patients with knee OA based on decreasing pain, improving function, global assessment and changes regarding joint imaging.

METHODS

We performed a comprehensive, systematic literature search in computerised databases (MEDLINE, EMBASE, CINAHL, CENTRAL, Web of Science and PEDro) until June 2014 for randomised or non-randomised controlled trials. These were graded for risk of bias and a level of evidence was provided. If possible, meta-analysis was performed.

RESULTS

Ten trials were included. In these, intra-articular PRP injections were more effective for pain reduction (mean difference (MD) -2.45; 95% CI -2.92 to -1.98; p value <0.00001 and MD -2.07; 95% CI -2.59 to -1.55; p value <0.00001, single and double PRP injections, respectively) compared with placebo at 6 months postinjection. Intra-articular PRP injections were compared with hyaluronic acid and showed a statistically significant difference in favour of PRP on pain reduction based on the visual analogue scale and numeric rating scale (standardised mean difference -0.92; 95% CI -1.20 to -0.63; p value <0.00001) at 6 months postinjection. Almost all trials revealed a high risk of bias.

CONCLUSIONS

On the basis of the current evidence, PRP injections reduced pain more effectively than did placebo injections in OA of the knee (level of evidence: limited due to a high risk of bias). This significant effect on pain was also seen when PRP injections were compared with hyaluronic acid injections (level of evidence: moderate due to a generally high risk of bias). Additionally, function improved significantly more when PRP injections were compared with controls (limited to moderate evidence). More large randomised studies of good quality and low risk of bias are needed to test whether PRP injections should be a routine part of management of patients with OA of the knee.

TNF-α/TNFR1 signaling is required for the development and function of primary nociceptors

Primary nociceptors relay painful touch information from the periphery to the spinal cord. Although it is established that signals generated by receptor tyrosine kinases TrkA and Ret coordinate the development of distinct nociceptive circuits, mechanisms modulating TrkA or Ret pathways in developing nociceptors are unknown. We have identified tumor necrosis factor (TNF) receptor 1 (TNFR1) as a critical modifier of TrkA and Ret signaling in peptidergic and nonpeptidergic nociceptors. Specifically, TrkA+ peptidergic nociceptors require TNF-α-TNFR1 forward signaling to suppress nerve growth factor (NGF)-mediated neurite growth, survival, excitability, and differentiation. Conversely, TNFR1-TNF-α reverse signaling augments the neurite growth and excitability of Ret+ nonpeptidergic nociceptors. The developmental and functional nociceptive defects associated with loss of TNFR1 signaling manifest behaviorally as lower pain thresholds caused by increased sensitivity to NGF. Thus, TNFR1 exerts a dual role in nociceptor information processing by suppressing TrkA and enhancing Ret signaling in peptidergic and nonpeptidergic nociceptors, respectively.

Future directions for the management of pain in osteoarthritis

Osteoarthritis (OA) is the predominant form of arthritis worldwide, resulting in a high degree of functional impairment and reduced quality of life owing to chronic pain. To date, there are no treatments that are known to modify disease progression of OA in the long term. Current treatments are largely based on the modulation of pain, including NSAIDs, opiates and, more recently, centrally acting pharmacotherapies to avert pain. This review will focus on the rationale for new avenues in pain modulation, including inhibition with anti-NGF antibodies and centrally acting analgesics. The authors also consider the potential for structure modification in cartilage/bone using growth factors and stem cell therapies. The possible mismatch between structural change and pain perception will also be discussed, introducing recent techniques that may assist in improved patient phenotyping of pain subsets in OA. Such developments could help further stratify subgroups and treatments for people with OA in future.

What about strontium ranelate in osteoarthritis? Doubts and securities

Abstract Osteoarthritis (OA) is the most common disabling joint disease worldwide and its treatment is based on a combination of non-pharmacological and pharmacological modalities. Commonly prescribed OA medications include symptomatic drugs (non-steroidal anti-inflammatory drugs, analgesics, locally administered corticosteroids, viscosupplementation) and new compounds that are potentially able to reduce or stop the disease progression, called "Disease Modifying Osteoarthritis Drugs (DMOADs)". Strontium ranelate (SR) is an anti-osteoporotic treatment that increases bone formation, while decreasing bone resorption and it potentially acts as a new DMOAD. The objective of this review is to summarize the currently available information on clinical effects and mechanism of action of SR in OA. We have examined two post hoc analysis conducted on the large, randomized Treatment of Peripheral Osteoporosis study and the double-blind, randomized, controlled trial about SR in knee OA. Furthermore, we analyzed three studies in animal models and two in vitro experiments to better understand the mechanism of action of SR in OA. The available data demonstrate that SR could be considered a new promising symptomatic and disease-modifying agent in the treatment of OA and was safe and well tolerated. Additionally, there is a need for further investigations to establish the optimal dosage and to better clarify the mechanism of action of SR in OA.

Induction of nerve growth factor expression and release by mechanical and inflammatory stimuli in chondrocytes: possible involvement in osteoarthritis pain

Introduction

Nerve growth factor (NGF) level is increased in osteoarthritis (OA) joints and is involved in pain associated with OA. Stimuli responsible for NGF stimulation in chondrocytes are unknown. We investigated whether mechanical stress and proinflammatory cytokines may influence NGF synthesis by chondrocytes.

Methods

Primary cultures of human OA chondrocytes, newborn mouse articular chondrocytes or cartilage explants were stimulated by increasing amounts of IL-1β, prostaglandin E₂ (PGE₂), visfatin/nicotinamide phosphoribosyltransferase (NAMPT) or by cyclic mechanical compression (0.5 Hz, 1 MPa). Before stimulation, chondrocytes were pretreated with indomethacin, Apo866, a specific inhibitor of NAMPT enzymatic activity, or transfected by siRNA targeting visfatin/NAMPT. mRNA NGF levels were assessed by real-time quantitative PCR and NGF released into media was determined by ELISA.

Results

Unstimulated human and mouse articular chondrocytes expressed low levels of NGF (19.2 ± 8.7 pg/mL, 13.5 ± 1.0 pg/mL and 4.4 ± 0.8 pg/mL/mg tissue for human and mouse articular chondrocytes and costal explants, respectively). Mechanical stress induced NGF release in conditioned media. When stimulated by IL-1β or visfatin/NAMPT, a proinflammatory adipokine produced by chondocytes in response to IL-1β, a dose-dependent increase in NGF mRNA expression and NGF release in both human and mouse chondrocyte conditioned media was observed. Visfatin/NAMPT is also an intracellular enzyme acting as the rate-limiting enzyme of the generation of NAD. The expression of NGF induced by visfatin/NAMPT was inhibited by Apo866, whereas IL-1β-mediated NGF expression was not modified by siRNA targeting visfatin/NAMPT. Interestingly, PGE₂, which is produced by chondrocytes in response to IL-1β and visfatin/NAMPT, did not stimulate NGF production. Consistently, indomethacin, a cyclooxygenase inhibitor, did not counteract IL-1β-induced NGF production.

Conclusions

These results show that mechanical stress, IL-1β and extracellular visfatin/NAMPT, all stimulated the expression and release of NGF by chondrocytes and thus suggest that the overexpression of visfatin/NAMPT and IL-1β in the OA joint and the increased mechanical loading of cartilage may mediate OA pain via the stimulation of NGF expression and release by chondrocytes.