Combination of Enzymes and Rutin to Manage Osteoarthritis Symptoms: Lessons from a Narrative Review of the Literature.

Osteoarthritis is the most common joint disorder affecting over 300 million people worldwide. It typically affects the knees and the hips, and is characterized by a loss in normal joint movement, stiffness, swelling, and pain in patients. The current gold standard therapy for osteoarthritis targets pain management using nonsteroidal anti-inflammatory drugs (NSAIDs). NSAIDs are associated with several potentially serious side effects, the most common being gastrointestinal perforation and bleeding. Owing to the side effects, NSAID treatment doses need to be as low as possible and should be continued for the shortest duration possible, which is problematic in a chronic condition like osteoarthritis, which requires long-term management. Numerous clinical trials have examined oral enzyme combinations as a potential new approach in managing pain in patients with osteoarthritis. Oral enzyme combinations containing bromelain in combination with trypsin, both proteolytic enzymes, as well as the plant flavonoid rutin, may be an effective alternative to typical NSAIDs. The aim of this narrative review is to summarize and discuss the evidence on the efficacy of oral enzyme combinations compared to the gold standard (NSAID) in the management of osteoarthritis symptoms. Nine randomized controlled trials identified in this review assessed the efficacy and safety of the oral enzyme combination containing bromelain, trypsin, and rutin in patients with osteoarthritis. Most of the studies assessed the impact of the oral enzyme combination on the improvement of the Lequesne Algofunctional index score, treatment-related pain intensity alterations and adverse events compared to patients receiving NSAIDs. Although largely small scale, the study outcomes suggest that this combination is as effective as NSAIDs in the management of osteoarthritis, without the adverse events associated with NSAID use. INFOGRAPHIC.

Fib3-3 as a Biomarker for Osteoarthritis in a Rat Model with Metabolic Dysregulation.

OBJECTIVE: Fibulin-3 is a glycoprotein highly expressed in osteoarthritic cartilage and inhibits angiogenesis and chondrocyte differentiation. Recent studies have indicated that fibulin-3 has potential value as a biomarker in osteoarthritis. The aim of the present study is to examine the role of 3 fibulin-3 peptides (Fib3-1, Fib3-2, and Fib3-3) and a type II collagen degradation product in a rat osteoarthritis model with systemic metabolic alterations combined with local cartilage damage. DESIGN: Forty, 12-week-old male, Wistar rats were randomly divided over 2 groups: a standard or a high-fat diet inducing metabolic dysregulation. After 12 weeks, articular cartilage damage was induced on the femoral condyles (groove model), in 1 knee joint in 14 rats of each diet group. At endpoint, blood was collected and serum was isolated. Enzyme-linked immunosorbent assay on all selected fibulin-3 fragments was performed from serum samples in addition to immunohistochemical analysis for Fib3-3. RESULTS: Serum concentrations of Fib3-3 were increased by 29.9%, when cartilage damage was induced in addition to a high-fat diet. Fib3-3 was also associated with an increased histological total joint degeneration (r = 0.435) and cartilage degeneration (r = 0.435). Immunostainings demonstrated increased Fib3-3 in the superficial cartilage of animals with high-fat diet and/or cartilage damage. CONCLUSIONS: In the rat groove model combined with high-fat diet-induced metabolic dysregulation an increased Fib3-3 concentration was observed systemically, which is associated with local joint degeneration. This suggests that systemic Fib3-3 concentrations can indicate the status of joint degeneration and function as a biomarker in osteoarthritis.

Review of Soluble Biomarkers of Osteoarthritis: Lessons From Animal Models.

Objective Osteoarthritis (OA) is one of the leading causes of disability within the adult population. Currently, its diagnosis is mainly based on clinical examination and standard radiography. To date, there is no way to detect the disease at a molecular level, before the appearance of structural changes and symptoms. So an attractive alternative for monitoring OA is the measurement of biochemical markers in blood, urine, or synovial fluid, which could reflect metabolic changes in joint tissue and therefore disease onset and progression. Animal models are relevant to investigate the early stage of OA and metabolic changes occurring in joint tissues. The goal of this narrative review is to summarize the scientific data available in the literature on soluble biomarkers in animal models of OA. Design A literature search was conducted using the PubMed/Medline and Scopus databases between February 1995 and December 2015. All original articles, systematic and narrative reviews published in French or in English were considered. Results We summarized the data of 69 studies and proposed a classification scheme for OA biomarkers in animal studies, largely inspired by the BIPEDS classification. Conclusions Studies about biomarkers and animal models indicate that some markers could be valuable to monitor OA progression and assess therapeutic response in some animal models.

Regulation of subchondral bone osteoblast metabolism by cyclic compression.

OBJECTIVE: Recent data have shown that abnormal subchondral bone remodeling plays an important role in osteoarthritis (OA) onset and progression, and it was suggested that abnormal mechanical pressure applied to the articulation was responsible for these metabolic changes. This study was undertaken to evaluate the effects of cyclic compression on osteoblasts from OA subchondral bone. METHODS: Osteoblasts were isolated from sclerotic and nonsclerotic areas of human OA subchondral bone. After 28 days, the osteoblasts were surrounded by an abundant extracellular matrix and formed a resistant membrane, which was submitted to cyclic compression (1 MPa at 1 Hz) for 4 hours. Gene expression was evaluated by reverse transcription-polymerase chain reaction. Protein production in culture supernatants was quantified by enzyme-linked immunosorbent assay or visualized by immunohistochemistry. RESULTS: Compression increased the expression of genes coding for interleukin-6 (IL-6), cyclooxygenase 2, RANKL, fibroblast growth factor 2, IL-8, matrix metalloproteinase 3 (MMP-3), MMP-9, and MMP-13 but reduced the expression of osteoprotegerin in osteoblasts in both sclerotic and nonsclerotic areas. Colα1(I) and MMP-2 were not significantly affected by mechanical stimuli. Nonsclerotic osteoblasts were significantly more sensitive to compression than sclerotic ones, but after compression, differences in messenger RNA levels between nonsclerotic and sclerotic osteoblasts were largely reduced or even abolished. Under basal conditions, sclerotic osteoblasts expressed similar levels of α5, αv, ß1, and ß3 integrins and CD44 as nonsclerotic osteoblasts but 30% less connexin 43, an important mechanoreceptor. CONCLUSION: Genes involved in subchondral bone sclerosis are mechanosensitive. After compression, nonsclerotic and sclerotic osteoblasts expressed a similar phenotype, suggesting that compression could be responsible for the phenotype changes in OA subchondral osteoblasts.

Phenotypic characterization of osteoblasts from the sclerotic zones of osteoarthritic subchondral bone.

OBJECTIVE: To determine the phenotype of osteoblasts from the sclerotic zones of human osteoarthritic (OA) subchondral bone. METHODS: Human osteoblasts were isolated from sclerotic or nonsclerotic areas of subchondral bone and cultured for 14 days in monolayer. The expression of 14 genes was investigated by real-time reverse transcription-polymerase chain reaction. The activities of alkaline phosphatase (AP) and transglutaminases (TGases) were quantified by enzymatic assays. C-terminal type I procollagen propeptide (CPI), interleukin-1beta (IL-1beta), IL-6, IL-8, transforming growth factor beta1 (TGFbeta1), osteocalcin (OC), and osteopontin (OPN) were assayed in the culture medium by immunoassay. RESULTS: Gene expression levels of matrix metalloproteinase 13, COL1A1 and COL1A2, OPN, tissue-nonspecific AP, OC, vascular endothelial growth factor, ANKH, TGase 2, factor XIIIA, and dentin matrix protein 1 were significantly up-regulated in sclerotic osteoblasts compared with nonsclerotic osteoblasts. In contrast, parathyroid hormone receptor gene expression was depressed in sclerotic osteoblasts, but bone sialoprotein levels were unchanged. The activities of AP and TGases were increased in sclerotic osteoblasts, while matrix mineralization, revealed by alizarin red staining, was decreased. In parallel, protein synthesis of CPI, OC, OPN, IL-6, IL-8, and TGFbeta1 was significantly higher in sclerotic osteoblasts than in nonsclerotic osteoblasts, while IL-1beta production was similar in both groups. CONCLUSION: These findings contribute to a better understanding of the mechanisms involved in subchondral bone sclerosis and identify osteoblasts with an altered phenotype as a potential target for future OA therapies.

Avocado/soybean unsaponifiables prevent the inhibitory effect of osteoarthritic subchondral osteoblasts on aggrecan and type II collagen synthesis by chondrocytes.

OBJECTIVE: To determine the effects of avocado/soybean unsaponifiables (ASU) on osteoblast-induced dysregulation of chondrocyte metabolism. METHODS: Human chondrocytes were isolated from osteoarthritis (OA) cartilage and cultured in alginate beads for 4 or 10 days in the absence or presence of osteoblasts isolated from nonsclerotic (NSC) or sclerotic (SC) zones of OA subchondral bone plate in monolayer. Before co-culture, osteoblasts were incubated or not with 10 microg/ml ASU for 72 hours. Aggrecan, type II collagen, matrix metalloproteinase-3 (MMP-3) and MMP-13, tissue inhibitor of metalloproteinase (TIMP-1), transforming growth factor-beta1 (TGF-beta1) and TGF-beta3, inducible NO synthase (iNOS), and cyclooxygenase-2 (COX-2) mRNA levels in chondrocytes were quantified by RT-PCR. Aggrecan, osteocalcin, TGF-beta1, interleukin 1beta (IL-1beta), and IL-6 production were assayed by immunoassays. RESULTS: In co-culture, SC osteoblasts induced a significant inhibition of matrix protein production and a significant increase of MMP synthesis by chondrocytes. In contrast, SC osteoblasts did not modify TIMP-1, TGF-beta1 and TGF-beta3, iNOS, or COX-2 mRNA levels in chondrocytes. The pretreatment of SC osteoblasts with ASU fully prevented the inhibitory effects of SC osteoblasts on matrix component production, and even significantly increased type II collagen mRNA level over the control (chondrocytes alone) value. In contrast, pretreatment of SC osteoblasts with ASU did not significantly modify the expression of MMP, TIMP-1, TGF-beta1, TGF-beta3, iNOS, or COX-2 gene by chondrocytes. CONCLUSION: ASU prevent the osteoarthritic osteoblast-induced inhibition of matrix molecule production, suggesting that this compound may promote OA cartilage repair by acting on subchondral bone osteoblasts. This finding constitutes a new mechanism of action for this compound, known for its beneficial effects on cartilage.

Differential regulation of chondrocyte metabolism by oncostatin M and interleukin-6.

OBJECTIVE: To determine the effects of interleukin (IL)-6 and oncostatin M (OSM) added separately or in combination with IL-1beta on human osteoarthritic (OA) chondrocytes in alginate beads. DESIGN: Human chondrocytes were isolated from OA cartilage and cultured in alginate beads for 12 days, in the absence or in the presence of increasing amounts of IL-6 (20-500ng/ml) with its soluble receptor or OSM (0.1-10ng/ml) and with or without IL-1beta (1.7ng/ml). Aggrecan (AGG), transforming growth factor-beta1 (TGF-beta1), stromelysin-1 [matrix metalloprotease (MMP)-3], tissue inhibitor of metalloproteinases-1 (TIMP-1), macrophage inflammatory protein-1 beta (MIP-1beta), IL-6 and IL-8 productions were assayed by specific enzyme amplified sensitivity immunoassays. Prostaglandin (PG)E(2) was measured by a specific radioimmunoassay and nitrite (NO(2)(-)) by a spectrophotometric method based upon the Griess reaction. RESULTS: OSM, but not IL-6, decreased basal AGG and TGF-beta1 synthesis. Although IL-6 stimulated basal TIMP-1 production, it did not significantly modify MMP-3/TIMP-1 ratio. In contrast, 10ng/ml OSM highly increased TIMP-1 production, and decreased by half the ratio MMP-3/TIMP-1. IL-1beta highly stimulated *NO, IL-8, IL-6, MIP-1beta and PGE(2) synthesis but decreased AGG and TGF-beta1 production. Neither IL-6 nor OSM modulated IL-1beta-inhibitory effect on AGG production. IL-6, but not OSM, reversed IL-1beta-induced TGF-beta1 inhibition. At 1-10ng/ml, OSM significantly decreased IL-1beta-stimulated IL-8, MIP-1beta, PGE(2) and *NO production but amplified IL-1beta stimulating effect on IL-6 production. IL-6 had no effect on these parameters. CONCLUSIONS: OSM and IL-6, two glycoprotein 130 binding cytokines, show different activity profiles on OA chondrocytes, indicating that these cytokines could play different roles in the OA disease process.

Avocado/soybean unsaponifiables increase aggrecan synthesis and reduce catabolic and proinflammatory mediator production by human osteoarthritic chondrocytes.

OBJECTIVE: To investigate the effects of avocado (A)/soybean (S) unsaponifiables on the metabolism of human osteoarthritic (OA) chondrocytes cultured in alginate beads over 12 days. METHODS: Enzymatically isolated OA chondrocytes were cultured in alginate beads in a well defined culture medium for 12 days, in the presence or not of 10-10 M interleukin 1beta (IL-1beta). DNA content was measured using a fluorometric method. Production of aggrecan (AGG), stromelysin-1 (MMP-3), tissue inhibitor of metalloproteinases-1 (TIMP-1), macrophage inflammatory protein-1beta (MIP-1beta), IL-6, and IL-8 were assayed by specific enzyme amplified sensitivity immunoassays. Prostaglandin (PG) E2 was measured by a specific radioimmunoassay and nitrite by a spectrophotometric method based on the Griess reaction. A commercial avocado and soybean mixture of unsaponifiables (A1S2) and each component separately were tested in a range of 0.625 to 40.0 micro g/ml. RESULTS: After 12 days' incubation, A1S2 increased AGG synthesis and accumulation in alginate beads in a dose and time dependent manner. A1S2 promoted the recovery of aggrecan synthesis after 3 days of IL-1beta treatment. A1S2 was a potent inhibitor of basal and IL-1beta stimulated MMP-3 production. The procedure also weakly reversed the inhibitory effect of IL-1beta on TIMP-1 production. A1S2 inhibited basal production of MIP-1beta, IL-6, IL-8, NO*, and PGE2 by OA chondrocytes and partially counteracted the stimulating effect of IL-1 on PGE2. Compared to avocado or soybean added separately, the mixture had a superior effect on NO* and IL-8 production. CONCLUSION: A1S2 stimulated aggrecan production and restored aggrecan production after IL-1beta treatment. In parallel, A1S2 decreased MMP-3 production and stimulated TIMP-1 production. These results suggest A1S2 could have structure-modifying effects in OA by inhibiting cartilage degradation and promoting cartilage repair.

Impact of the joint space width measurement method on the design of knee osteoarthritis studies.

BACKGROUND AND AIMS: Recent guidelines recommend measurement of articular loss over several years, determined by conventional X-rays, as the principal outcome measure in clinical trials of potential structure-modifying drugs in osteoarthritis (OA). The aim of this study was to assess the impact of the joint space width measurement method on sample size calculation in knee OA studies. METHODS: Standard knee X-rays were taken in 212 patients with knee OA at baseline and after 3 years of follow-up. Mean joint space width (JSW) was measured with an in-house computer-assisted method. Minimum JSW, measured with a graduated magnifying lens, was taken as external standard. After calculation of the intra- and inter-observer reproducibility of the JSW, sensitivity to change was assessed using the standardized response mean (SRM). The number of patients needed to identify a mean significant difference of 0.5 mm in joint space narrowing between the placebo and the treated group, after 3 years of follow-up, was then calculated. RESULTS: JSW measured with the computer-assisted technique showed better intra- and inter-observer reproducibility than when using the magnifying lens. JSW values measured with our computer-assisted method were significantly correlated with JSW values obtained using the magnifying lens (r=0.87, p<0.001). The SRM were 0.44 and 0.40 for the computer-assisted method and magnifying lens, respectively. The number of patients needed was 131 per group using the computer-assisted method, and 104 using the magnifying lens. CONCLUSIONS: Our method of measurement of JSW may be of potential use in longitudinal studies evaluating the effect of structure-modifying drugs in OA, due to its high level of precision and efficiency. However, although sensitivity to change is markedly better with the digitized method compared with the graduated magnifying lens, we recommend the measurement of mean and minimum JSW in structure-modifying OA trials.

Biochemical markers of bone and cartilage remodeling in prediction of longterm progression of knee osteoarthritis.

OBJECTIVE: To investigate the relationship between biochemical markers of bone and cartilage remodeling and severity or progression (symptoms and structure) of knee osteoarthritis (OA). METHODS: Mean and minimal joint space width (JSW) of the femorotibial joint were measured from standardized radiographs taken at baseline and at the end of a 3-year longitudinal study of patients with knee OA. Pain, stiffness, and physical function subscales of the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index were assessed at the same time points. Biochemical markers [serum keratan sulfate (KS), serum hyaluronic acid (HA), urine pyridinoline (PYD) and deoxypyridinoline (DPD), serum osteocalcin (OC), cartilage oligomeric matrix protein (COMP)] were assessed at baseline and after 1 year. RESULTS: At baseline, no significant correlations were observed between values of biochemical markers and JSW or any of the WOMAC scores. Baseline markers were not correlated with 3-year percentage changes observed in mean or minimal JSW and WOMAC scores. Changes observed after 1 year in OC and HA were significantly correlated with 3-year progression in mean JSW (r = -0.24, p = 0.04 and r = 0.27, p = 0.02, respectively) and in minimal JSW (r = -0.31, p = 0.01 and r = 0.24, p = 0.04, respectively). In patients from the lowest quartile of 1-year changes in HA (< -21.22 ng/ml), mean JSW decreased after 3 years by 0.76 (1.23) mm compared to an increase of 0.11 (0.83) mm in patients in the highest quartile (> +14.34 ng/ml) (p = 0.03). CONCLUSION: The 3-year radiological progression of knee OA could be predicted by a 1-year increase in OC or a 1-year decrease in HA levels.

Effects of rhein on human articular chondrocytes in alginate beads.

This study was designed to investigate the effects of rhein, the active metabolite of diacerhein, on the metabolic functions of human chondrocytes cultured in alginate beads. Enzymatically isolated osteoarthritic (OA) chondrocytes were cultured in alginate beads in a well-defined culture medium for 12 days. Rhein was tested in a range of concentrations comprised between 10(-7) and 4 x 10(-5)M, in the presence or absence of 10(-10)M IL-1beta. Interleukin (IL)-6 and -8, macrophage inflammatory protein (MIP-1beta), stromelysin-1 (MMP-3), aggrecan (AGG), tissue inhibitor of metalloproteinases-1 (TIMP-1), prostaglandin E(2) (PGE(2)) and nitric oxide (NO) productions were assayed. Cyclooxygenase-2 (COX-2) and inducible NO synthase (iNOS) mRNA steady-state levels were also quantified. In the basal condition, 10(-5)M rhein increased by 46.5% the production of AGG, decreased by 17-30% the production of IL-6, MMP-3, NO and MIP-1beta but enhanced by 50% the production of PGE(2). IL-1beta increased IL-6, IL-8, MIP-1beta, NO, PGE(2) and MMP-3 productions, but inhibited AGG and TIMP-1 synthesis. Rhein partially reversed the effect of IL-1beta on TIMP-1 and NO production, had no effect on AGG, IL-6 and MIP-1beta production, but up-regulated the IL-1beta stimulated PGE(2) production. The COX-2 and iNOS mRNA levels and IL-8 production were not modified by rhein.Overall, these results contribute to explain the clinical efficiency of rhein and give new information on its mechanisms of action.

Radiologic features poorly predict clinical outcomes in knee osteoarthritis.

OBJECTIVES: To assess the impact of radiographic severity and progression on pain and disability. METHODS: Measurements of mean joint space width (JSW), narrowest join space (NJS) point and assessment of symptoms by the WOMAC questionnaire were performed at baseline and after three years in 212 subjects over 50 years with primary knee OA. RESULTS: At baseline, JSW and NJS were not significantly correlated with the scores recorded for the WOMAC global index or its pain, stiffness or function subscales. A statistically significant correlation was observed between the joint space narrowing over three years and the changes observed in the pain subscale of the WOMAC during the same period. The three-year changes in the global WOMAC index in patients within the lowest and the highest quartiles of mean joint space width at baseline showed, in both cases, a statistically (p<0.05) significant favorable difference between patients treated with glucosamine sulphate and those having received placebo. CONCLUSION: Radiographic and clinical progressions of the disease are significantly associated but the clinical relevance of the association is questionable.

Metabolism of human articular chondrocytes cultured in alginate beads. Longterm effects of interleukin 1beta and nonsteroidal antiinflammatory drugs.

OBJECTIVES: To investigate the longterm effects (12 days) of nonsteroidal antiinflammatory drugs [NSAID: aceclofenac (ACECLO), sodium diclofenac (DICLO), indomethacin (INDO), nimesulide (NIM), rofecoxib (ROFE), celecoxib (CELE), piroxicam (PIROX), and ibuprofen (IBUP)] on the metabolism of human chondrocytes cultured in alginate beads. METHODS: Enzymatically isolated osteoarthritic (OA) chondrocytes were cultured in alginate beads in a well defined culture medium for 12 days. The DNA content was measured according to a fluorimetric method and cell proliferation was determined by the incorporation of 3H-thymidine in the newly synthesized DNA. Interleukin 6 (IL-6) and IL-8, stromelysin [matrix metalloproteinase-3 (MMP-3)], and aggrecan (AGG) production were assayed by specific enzyme amplified sensitivity immunoassays, and prostaglandin E2 (PGE2) production by specific radioimmunoassay. All NSAID were tested at the mean peak plasma concentration (Cmax) obtained after oral administration of a therapeutic dose. RESULTS: In alginate beads, chondrocytes synthesized high amounts of AGG, which were largely (98%) immobilized in the alginate matrix. A large amount (43%) of the IL-8 produced was stored in the alginate beads, whereas almost all IL-6 production (94%) was released in the culture supernatant. At the therapeutic concentration, all NSAID tested fully blocked PGE2 production. ACECLO, DICLO, INDO, NIM significantly inhibited basal and IL-1beta stimulated IL-6 production; CELE and IBUP only inhibited IL-1beta stimulated IL-6 production; and ROFE and PIROX had no significant effects. No NSAID showed significant effects on basal and IL-1beta stimulated IL-8 production, except CELE and IBUP, which slightly increased basal IL-8 production. ACECLO and INDO increased AGG content by 25% in the alginate beads, while the other NSAID were without significant effect. No NSAID were able to modify the inhibitory effect of IL-1beta on AGG production. NSAID did not modify MMP-3 production. CONCLUSION: The mechanism of action of NSAID seems to be multifactorial and not limited to the inhibition of cyclooxygenases. Further, in our culture conditions, at the Cmax and by comparison with other NSAID, ACECLO and INDO show an advantageous activity profile. They fully blocked PGE2 production, inhibited IL-6 synthesis, and increased aggrecan synthesis. These effects appear advantageous for the longterm treatment of chronic joint diseases such as osteoarthritis.