Jordi Monfort

Biochemical basis of the effect of chondroitin sulphate on osteoarthritis articular tissues

Osteoarthritis is a chronic disease characterised by irreversible damage to joint structures, including loss of articular cartilage, osteophyte formation, alterations in the subchondral bone and synovial inflammation. Pain, functional disability and impairment of health-related quality of life are major complaints in patients with osteoarthritis. Several compounds have been investigated for their positive effects on the relief of clinical symptoms and improvement of structural changes in osteoarthritis. It has been shown that chondroitin sulphate interferes with the progression of structural changes in joint tissues and is used in the management of patients with osteoarthritis. This review summarises data from relevant reports describing the mechanisms of action of chondroitin sulphate involved in the beneficial effects of the drug.

Combined chondroitin sulfate and glucosamine for painful knee osteoarthritis: a multicentre, randomised, double-blind, non-inferiority trial versus celecoxib

Objectives To compare the efficacy and safety of chondroitin sulfate plus glucosamine hydrochloride (CS+GH) versus celecoxib in patients with knee osteoarthritis and severe pain. Methods Double-blind Multicentre Osteoarthritis interVEntion trial with SYSADOA (MOVES) conducted in France, Germany, Poland and Spain evaluating treatment with CS+GH versus celecoxib in 606 patients with Kellgren and Lawrence grades 2–3 knee osteoarthritis and moderate-to-severe pain (Western Ontario and McMaster osteoarthritis index (WOMAC) score ≥301; 0–500 scale). Patients were randomised to receive 400 mg CS plus 500 mg GH three times a day or 200 mg celecoxib every day for 6 months. The primary outcome was the mean decrease in WOMAC pain from baseline to 6 months. Secondary outcomes included WOMAC function and stiffness, visual analogue scale for pain, presence of joint swelling/effusion, rescue medication consumption, Outcome Measures in Rheumatology Clinical Trials and Osteoarthritis Research Society International (OMERACT-OARSI) criteria and EuroQoL-5D. Results The adjusted mean change (95% CI) in WOMAC pain was −185.7 (−200.3 to −171.1) (50.1% decrease) with CS+GH and −186.8 (−201.7 to −171.9) (50.2% decrease) with celecoxib, meeting the non-inferiority margin of −40: −1.11 (−22.0 to 19.8; p=0.92). All sensitivity analyses were consistent with that result. At 6 months, 79.7% of patients in the combination group and 79.2% in the celecoxib group fulfilled OMERACT-OARSI criteria. Both groups elicited a reduction >50% in the presence of joint swelling; a similar reduction was seen for effusion. No differences were observed for the other secondary outcomes. Adverse events were low and similarly distributed between groups. Conclusions CS+GH has comparable efficacy to celecoxib in reducing pain, stiffness, functional limitation and joint swelling/effusion after 6 months in patients with painful knee osteoarthritis, with a good safety profile. Trial registration number: NCT01425853.

The contribution of sensory system functional connectivity reduction to clinical pain in fibromyalgia

Summary Clinical pain in fibromyalgia is associated with functional changes at different brain levels in a pattern suggesting a general weakening of sensory integration. ABSTRACT Fibromyalgia typically presents with spontaneous body pain with no apparent cause and is considered pathophysiologically to be a functional disorder of somatosensory processing. We have investigated potential associations between the degree of self‐reported clinical pain and resting‐state brain functional connectivity at different levels of putative somatosensory integration. Resting‐state functional magnetic resonance imaging was obtained in 40 women with fibromyalgia and 36 control subjects. A combination of functional connectivity‐based measurements were used to assess (1) the basic pain signal modulation system at the level of the periaqueductal gray (PAG); (2) the sensory cortex with an emphasis on the parietal operculum/secondary somatosensory cortex (SII); and (3) the connectivity of these regions with the self‐referential “default mode” network. Compared with control subjects, a reduction of functional connectivity was identified across the 3 levels of neural processing, each showing a significant and complementary correlation with the degree of clinical pain. Specifically, self‐reported pain in fibromyalgia patients correlated with (1) reduced connectivity between PAG and anterior insula; (2) reduced connectivity between SII and primary somatosensory, visual, and auditory cortices; and (3) increased connectivity between SII and the default mode network. The results confirm previous research demonstrating abnormal functional connectivity in fibromyalgia and show that alterations at different levels of sensory processing may contribute to account for clinical pain. Importantly, reduced functional connectivity extended beyond the somatosensory domain and implicated visual and auditory sensory modalities. Overall, this study suggests that a general weakening of sensory integration underlies clinical pain in fibromyalgia.

Altered Functional Magnetic Resonance Imaging Responses to Nonpainful Sensory Stimulation in Fibromyalgia Patients

Fibromyalgia (FM) is a disorder characterized by chronic pain and enhanced responses to acute noxious events. However, the sensory systems affected in FM may extend beyond pain itself, as FM patients show reduced tolerance to non‐nociceptive sensory stimulation. Characterizing the neural substrates of multisensory hypersensitivity in FM may thus provide important clues about the underlying pathophysiology of the disorder. The aim of this study was to characterize brain responses to non‐nociceptive sensory stimulation in FM patients and their relationship to subjective sensory sensitivity and clinical pain severity.

Decreased metalloproteinase production as a response to mechanical pressure in human cartilage: a mechanism for homeostatic regulation

Articular cartilage is optimised for bearing mechanical loads. Chondrocytes are the only cells present in mature cartilage and are responsible for the synthesis and integrity of the extracellular matrix. Appropriate joint loads stimulate chondrocytes to maintain healthy cartilage with a concrete protein composition according to loading demands. In contrast, inappropriate loads alter the composition of cartilage, leading to osteoarthritis (OA). Matrix metalloproteinases (MMPs) are involved in degradation of cartilage matrix components and have been implicated in OA, but their role in loading response is unclear. With this study, we aimed to elucidate the role of MMP-1 and MMP-3 in cartilage composition in response to mechanical load and to analyse the differences in aggrecan and type II collagen content in articular cartilage from maximum- and minimum-weight-bearing regions of human healthy and OA hips. In parallel, we analyse the apoptosis of chondrocytes in maximal and minimal load areas. Because human femoral heads are subjected to different loads at defined sites, both areas were obtained from the same hip and subsequently evaluated for differences in aggrecan, type II collagen, MMP-1, and MMP-3 content (enzyme-linked immunosorbent assay) and gene expression (real-time polymerase chain reaction) and for chondrocyte apoptosis (flow cytometry, bcl-2 Western blot, and mitochondrial membrane potential analysis). The results showed that the load reduced the MMP-1 and MMP-3 synthesis (p < 0.05) in healthy but not in OA cartilage. No significant differences between pressure areas were found for aggrecan and type II collagen gene expression levels. However, a trend toward significance, in the aggrecan/collagen II ratio, was found for healthy hips (p = 0.057) upon comparison of pressure areas (loaded areas > non-loaded areas). Moreover, compared with normal cartilage, OA cartilage showed a 10- to 20-fold lower ratio of aggrecan to type II collagen, suggesting that the balance between the major structural proteins is crucial to the integrity and function of the tissue. Alternatively, no differences in apoptosis levels between loading areas were found – evidence that mechanical load regulates cartilage matrix composition but does not affect chondrocyte viability. The results suggest that MMPs play a key role in regulating the balance of structural proteins of the articular cartilage matrix according to local mechanical demands.

Identification of opticin, a member of the small leucine-rich repeat proteoglycan family, in human articular tissues : a novel target for MMP-13 in osteoarthritis

OBJECTIVE One of the proteoglycan families is the small leucine-rich proteoglycans (SLRPs) that are characterized by their association with collagen fibrils and/or some glycosaminoglycans. Opticin is a glycoprotein and class III member of the SLRP family, which was initially identified in the vitreous humour of the eye. In this study, we first investigated whether opticin is expressed and produced in normal and OA human articular tissues/cells. Further, we investigated the ability of the key metalloprotease involved in cartilage pathology, MMP-13, to cleave human cartilage opticin. METHODS Opticin gene expression was investigated in normal and OA human chondrocytes, synovial fibroblasts, and subchondral bone osteoblasts by reverse transcriptase-polymerase chain reaction (RT-PCR). Opticin protein production was determined in normal and OA synovial membrane and cartilage by immunohistochemistry. Opticin was isolated from human cartilage using guanidinium chloride extraction, and human MMP-13-induced opticin degradation analyzed by Western blotting. Finally, the opticin MMP-13 cleavage site was determined. RESULTS Opticin was expressed in human chondrocytes, synovial fibroblasts and subchondral osteoblasts, and the protein identified in synovial membrane and cartilage. At the protein level, OA cartilage showed a slightly higher level of opticin positive stained chondrocytes than normal cartilage; this did not reach statistical significance. However, in contrast with OA, normal cartilage demonstrated a high level of matrix staining in the superficial zone of the tissue, suggesting that in the OA cartilage matrix, opticin is degraded. Data also showed that cartilage opticin could be cleaved by MMP-13 after only 2h of incubation, indicating a preferential substrate compared to other SLRPs for this enzyme. Microsequencing revealed a major cleavage site at the G(104)/L(105)LAAP and a minor at P(109)/A(110)NHPG upon MMP-13 exposure. CONCLUSION We demonstrated, for the first time, that opticin is expressed and produced in human articular tissues. Our data also showed that opticin in OA cartilage is degraded in a process that could be mediated by MMP-13. As opticin may contribute towards the structural stability of cartilage, its cleavage by MMP-13 may predispose cartilage to degeneration, particularly at the surface.

Chondroitin sulphate for symptomatic osteoarthritis: critical appraisal of meta-analyses

ABSTRACT Background: Chondroitin sulphate (CS) is an important structural component of cartilage and is approved and regulated as a symptomatic slow-acting drug for osteoarthritis (OA) (SYSADOA) in Europe and some other countries. Although numerous studies have shown the clinical benefits of CS to decrease pain, improve functional disability, reduce non-steroidal anti-inflammatory drug (NSAID) or acetaminophen consumption, and good tolerability with an additional carry-over effect, there are still some concerns regarding its effectiveness in treating OA. Purpose: To examine the data provided by meta-analyses to clarify the effectiveness of CS as a symptomatic treatment for OA. Methods: A MEDLINE database search was conducted for appropriate meta-analyses published between 1997 and 2007. Five meta-analyses that limited their analysis to randomised controlled trials (RCTs) comparing CS with placebo or no-treatment control arms were retrieved. Results: Four meta-analyses showed significant clinical effects of CS compared with placebo for pain and function measures and one demonstrated greater reduction of analgesic co-medication in patients assigned to the active treatment. In one meta-analysis, the 20 trials included in the study showed a high degree of heterogeneity and the conclusion that CS showed minimal symptomatic benefits was based on the analysis of only three trials. One meta-analysis showed that pain relief after CS treatment steadily increased between 4 and 12 weeks of treatment, whereas the time course of pain relief after treatment with NSAIDs decreased. Two meta-analyses reported consistently higher frequencies of side effects in the placebo group than in patients treated with CS. Conclusion: Data provided by these meta-analyses indicate that CS has a slight to moderate efficacy in the symptomatic treatment of OA, with an excellent safety profile.

Effectiveness of chondroitin sulphate in patients with concomitant knee osteoarthritis and psoriasis: a randomized, double-blind, placebo-controlled study

OBJECTIVE The aim of the trial was to assess the efficacy of chondroitin sulphate (CS) on symptomatic knee osteoarthritis (OA) associated to psoriasis. METHODS In this randomized, double-blind, placebo (PBO)-controlled clinical trial 129 patients with symptomatic knee OA and concomitant psoriasis were randomized into two groups receiving 800 mg daily of CS or PBO for 3 months. The primary efficacy outcome for knee OA was the Huskissons visual analogue scale (VAS) and for psoriasis was the Psoriasis Area and Severity Index (PASI). Additionally, other secondary efficacy criteria for both conditions were assessed. RESULTS After 3 months of treatment, CS was more effective than PBO, relieving pain VAS (CS -26.9+/-24.8 vs PBO -14.23+/-20.8mm, P<0.01), decreasing the Lequesne index (CS -4.8+/-3.4 vs PBO -3.3+/-3.5, P<0.05) and reducing the number of patients using acetaminophen as rescue medication (CS 43% vs PBO 64%, P<0.05). Regarding PASI, Overall Lesion Severity Scale and Physicians Global Assessment of Change no statistically significant changes were detected in front of PBO. However, CS improved plantar psoriasis compared to PBO (CS 87% vs PBO 27%, P<0.05). Quality of life improved significantly in CS-treated patients according to the Short Form-36 health survey and the Dermatology Life Quality Index (DLQI). CS tolerability was excellent. Adverse events were infrequent and evenly distributed among groups. The incidence of psoriatic flares did not increase after treatments. CONCLUSIONS This study confirms the efficacy and safety of CS as a symptomatic slow-acting drug in patients with knee OA and shows that CS improves plantar psoriasis. The use of CS could represent a special benefit in patients with both pathologies since non-steroidal anti-inflammatory drugs have been reported to induce or exacerbate psoriasis.

Towards a neurophysiological signature for fibromyalgia

Abstract Patients with fibromyalgia (FM) show characteristically enhanced unpleasantness to painful and nonpainful sensations accompanied by altered neural responses. The diagnostic potential of such neural alterations, including their sensitivity and specificity to FM (vs healthy controls) is unknown. We identify a brain signature that characterizes FM central pathophysiology at the neural systems level. We included 37 patients with FM and 35 matched healthy controls, and analyzed functional magnetic resonance imaging responses to (1) painful pressure and (2) nonpainful multisensory (visual–auditory–tactile) stimulation. We used machine-learning techniques to identify a brain-based FM signature. When exposed to the same painful stimuli, patients with FM showed greater neurologic pain signature (NPS; Wager et al., 2013. An fMRI-based neurologic signature of physical pain. N Engl J Med 2013;368:1388–97) responses. In addition, a new pain-related classifier (“FM-pain”) revealed augmented responses in sensory integration (insula/operculum) and self-referential (eg, medial prefrontal) regions in FM and reduced responses in the lateral frontal cortex. A “multisensory” classifier trained on nonpainful sensory stimulation revealed augmented responses in the insula/operculum, posterior cingulate, and medial prefrontal regions and reduced responses in the primary/secondary sensory cortices, basal ganglia, and cerebellum. Combined activity in the NPS, FM pain, and multisensory patterns classified patients vs controls with 92% sensitivity and 94% specificity in out-of-sample individuals. Enhanced NPS responses partly mediated mechanical hypersensitivity and correlated with depression and disability (Puncorrected < 0.05); FM-pain and multisensory responses correlated with clinical pain (Puncorrected < 0.05). The study provides initial characterization of individual patients with FM based on pathophysiological, symptom-related brain features. If replicated, these brain features may constitute objective neural targets for therapeutic interventions. The results establish a framework for assessing therapeutic mechanisms and predicting treatment response at the individual level.

Comparative efficacy of intra-articular hyaluronic acid and corticoid injections in osteoarthritis of the first carpometacarpal joint: results of a 6-month single-masked randomized study.

OBJECTIVE The study aim was to compare the efficacy and safety of ultrasound-guided intra-articular injections of hyaluronic acid and betamethasone in the management of patients with osteoarthritis of the thumb. METHODS Eighty-eight evaluable patients diagnosed with osteoarthritis of the thumb (Kellgren-Lawrence grade II-III) received ultrasound-guided intra-articular treatment with hyaluronic acid (48) or betamethasone (40). In total, 3 local injections were scheduled at 7-day intervals. Assessments were performed at baseline and at 7, 14, 30, 90, and 180 days. RESULTS In both study groups, the pain Visual Analogue Scale and Functional Index for Hand Osteoarthritis scores decreased significantly during follow-up compared to baseline. There were no significant differences between the groups. However, at 90 days, the functional score showed a trend towards greater clinical improvement in the hyaluronic acid group (P 0.071). A subanalysis of patients with Functional Index score≥5 and Visual Analogue Scale score≥3 at baseline showed a significantly higher median functionality score in the hyaluronic acid group (P 0.005 at 90 days and P 0.020 at 180 days). Further limiting analysis to a baseline pain score≥5 showed significantly greater improvement in functionality score (P 0.004 at 180 days), which was already apparent after the second intra-articular injection at 14 days (P 0.028). In this patient subset, the mean pain score also improved significantly at 180 days (P 0.02). CONCLUSIONS Both hyaluronic acid and betamethasone were effective and well-tolerated for the management of rhizarthrosis. Hyaluronic acid was more effective over time and more efficiently improved functionality and pain in patients with more severe symptoms.