Exploring the Link between Uric Acid and Osteoarthritis

Colchicine combination therapy increases treatment tolerance in patients with arthritis: A systematic review and meta-analysis

BACKGROUND

Arthritis seriously affects people's quality of life, and there is an urgent clinical need to improve the efficacy of medications as well as to reduce the adverse effects induced by treatment. Combined colchicine therapy is gradually being embraced in clinical care, but the evidence remains insufficient.

METHODS

English databases were searched from the establishment to September 4, 2024. Eleven eligible Randomized controlled trials (RCTs) were included. The quality of the literature was assessed by the risk of bias tool in the Cochrane Handbook. Relative risk (RR) and Cohen's d (SMD) were used for categorical and continuous variables, respectively, at 95% confidence interval (CI), and Stata 17.0 software was used for statistical analysis. Sensitivity analyses were used to verify the stability of the analyzed results, and heterogeneity analyses were used to explore the sources of heterogeneity in the studies. Funnel plots and Egger's test were used to assess publication bias.

RESULTS

Eleven eligible RCTs were included in this study. Compared with conventional treatment, combined colchicine treatment improved patient's global assessment results (SMD = 1.24, 95% CI [0.01, 2.47], P = 0.05, I2 = 0]), stiffness (SMD = -0.81, 95% CI [-1.43, -0.19], P = 0.01, I2 = 63.91%]) and did not increase adverse effects (RR = 0.79, 95% CI [0.31, 1.27], P = 0.36, I2 = 0.00%). However, combined colchicine treatment did not improve visual analog scores (VAS) (SMD = -0.96, 95% CI [-2.85, 0.93], P = 0.13, I2 = 97.99%]), Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain (SMD = 0.01, 95% CI [-0.24, 0.27], P = 0.91, I2 = 0]), WOMAC function (SMD = -0.01, 95% CI [-0.36, 0.16], P = 0.44, I2 = 0]), Total WOMAC scale (SMD = -0.05, 95% CI [-0.33, 0.22], P = 0.70, I2 = 0]), physician 's global assessment (SMD = 0.36, 95% CI [-2.27, 3.00], P = 0.79, I2 = 97.04%]) and Modified Clinical Health Assessment Questionnaire (ModHAD) (SMD = -1.72, 95% CI [-4.90,1.45], P = 0.29, I2 = 99.11%]).

CONCLUSION

Compared with colchicine alone, combination therapy improves patients' quality of life without increasing the incidence of adverse events.

A comparative metabolomic analysis reveals the metabolic variations among cartilage of Kashin-Beck disease and osteoarthritis

Aims

The metabolic variations between the cartilage of osteoarthritis (OA) and Kashin-Beck disease (KBD) remain largely unknown. Our study aimed to address this by conducting a comparative analysis of the metabolic profiles present in the cartilage of KBD and OA.

Methods

Cartilage samples from patients with KBD (n = 10) and patients with OA (n = 10) were collected during total knee arthroplasty surgery. An untargeted metabolomics approach using liquid chromatography coupled with mass spectrometry (LC-MS) was conducted to investigate the metabolomics profiles of KBD and OA. LC-MS raw data files were converted into mzXML format and then processed by the XCMS, CAMERA, and metaX toolbox implemented with R software. The online Kyoto Encyclopedia of Genes and Genomes (KEGG) database was used to annotate the metabolites by matching the exact molecular mass data of samples with those from the database.

Results

A total of 807 ion features were identified for KBD and OA, including 577 positive (240 for upregulated and 337 for downregulated) and 230 negative (107 for upregulated and 123 for downregulated) ions. After annotation, LC-MS identified significant expressions of ten upregulated and eight downregulated second-level metabolites, and 183 upregulated and 162 downregulated first-level metabolites between KBD and OA. We identified differentially expressed second-level metabolites that are highly associated with cartilage damage, including dimethyl sulfoxide, uric acid, and betaine. These metabolites exist in sulphur metabolism, purine metabolism, and glycine, serine, and threonine metabolism.

Conclusion

This comprehensive comparative analysis of metabolism in OA and KBD cartilage provides new evidence of differences in the pathogenetic mechanisms underlying cartilage damage in these two conditions.

Cathelicidin-BF regulates the AMPK/SIRT1/NF-κB pathway to ameliorate murine osteoarthritis: In vitro and in vivo studie

Osteoarthritis (OA) is a chronic degenerative disease with a significant prevalence that causes cartilage damage and can lead to disability. The main factors contributing to the onset and progression of OA include inflammation and degeneration of the extracellular matrix. Cathelicidin-BF (BF-30), a natural peptide derived from Bungarus fasciatus venom, has shown multiple important pharmacological effects. However, the action mechanism of BF-30 in OA treatment remains to be elucidated. In this research, X-ray and Safranin O staining were employed to evaluate the imageology and histomorphology differences in the knee joints of mice in vivo. Techniques such as Western blot analysis, RT-qPCR, ELISA, and immunofluorescence staining were applied to examine gene and protein level changes in in vitro experiments. It was found that BF-30 significantly decreased inflammation and enhanced extracellular matrix metabolism. For the first time, it was demonstrated that the positive effects of BF-30 are mediated through the activation of the AMPK/SIRT1/NF-κB pathway. Moreover, when BF-30 was co-administered with Compound C, an AMPK inhibitor, the therapeutic benefits of BF-30 were reversed in both in vivo and in vitro settings. In conclusion, the findings suggest that BF-30 could be a novel therapeutic agent for OA improvement.

J-shaped association of serum uric acid concentrations with all-cause mortality in individuals with osteoarthritis: A prospective cohort study

OBJECTIVE

The purpose of this study was to explore the relationship between serum uric acid (SUA) concentrations and all-cause mortality in individuals with osteoarthritis (OA).

METHODS

All participant data were retrieved from the National Health and Nutrition Examination Survey database. A total of 4671 participants (age range: 20 to 85 years old), including 2988 females and 1683 males, were included in this study. The determination of death outcome was based on the National Death Index (up to December 31, 2019). We explored the nonlinear relationship between SUA concentrations and all-cause mortality in OA patients by establishing a Cox proportional risk model and a two-segment Cox proportional risk model and ran an interaction test to identify the high-risk population for all-cause mortality.

RESULTS

During 30,645 person-years of follow-up, the number of all-cause deaths for females and males was 736 and 516, respectively. After multivariate adjustment, we found a nonlinear relationship between SUA concentrations and all-cause mortality in both females and males with OA. In addition, we found a J-shaped relationship between SUA concentrations and all-cause mortality. The SUA concentration thresholds for all-cause mortality of females and males were stable at 5.6mg/dl and 6.2mg/dl, respectively. Compared with SUA concentrations below the inflection point, the all-cause mortality risk at higher SUA concentrations in females and males with OA increased by 20% (hazard ratio [HR]: 1.2, 95% confidence interval [CI]: 1.1 to 1.2) and 25% (HR: 1.2, 95% CI: 1.12 to 1.39), respectively.

CONCLUSIONS

There is a nonlinear relationship between SUA concentrations and all-cause mortality in the American OA population (J-shaped association). The all-cause mortality thresholds for SUA concentrations in females and males are 5.6mg/dl and 6.2mg/dl, respectively.

Targeting CD44 Receptor Pathways in Degenerative Joint Diseases: Involvement of Proteoglycan-4 (PRG4)

Rheumatoid arthritis (RA), osteoarthritis (OA), and gout are the most prevalent degenerative joint diseases (DJDs). The pathogenesis underlying joint disease in DJDs remains unclear. Considering the severe toxicities reported with anti-inflammatory and disease-modifying agents, there is a clear need to develop new treatments that are specific in their effect while not being associated with significant toxicities. A key feature in the development of joint disease is the overexpression of adhesion molecules, e.g., CD44. Expression of CD44 and its variants in the synovial tissues of patients with DJDs is strongly associated with cartilage damage and appears to be a predicting factor of synovial inflammation in DJDs. Targeting CD44 and its downstream signaling proteins has emerged as a promising therapeutic strategy. PRG4 is a mucinous glycoprotein that binds to the CD44 receptor and is physiologically involved in joint lubrication. PRG4-CD44 is a pivotal regulator of synovial lining cell hemostasis in the joint, where lack of PRG4 expression triggers chronic inflammation and fibrosis, driven by persistent activation of synovial cells. In view of the significance of CD44 in DJD pathogenesis and the potential biological role for PRG4, this review aims to summarize the involvement of PRG4-CD44 signaling in controlling synovitis, synovial hypertrophy, and tissue fibrosis in DJDs.

The effects of allogeneic and autologous blood transfusion on immune function in patients receiving total hip replacement

OBJECTIVE

To evaluate the effects of allogeneic and autologous blood transfusion on immune function and postoperative inflammation in patients after total hip replacement.

METHODS

In this retrospective study, the clinical data of 60 patients undergoing total hip arthroplasty through a posterolateral approach were analyzed. The patients were grouped into an autologous blood transfusion group (allo group) (n = 30) and an autologous blood transfusion group (auto-group) (n = 30) according to the treatment they received. All patients did not receive preoperative and intraoperative blood transfusion. The blood collected in the operation area was transfused to the patients in the auto-group with the autotransfusion device and the allogeneic blood was transfused to the patients in the allo-group after the operation. The average amount of blood transfusion was 400 ml. The immune function after blood transfusion was mainly evaluated by natural killer cell cytotoxicity (NKCC) and interleukin-2 (IL-2) using ELISA kits, meanwhile the changes of cellular immune factor levels (differentiation cluster of differentiation, CD) (CD3+, CD4+) and humoral immune factor levels (Immunoglobulin E, IgE) after blood transfusion were determined by flow cytometry. The secondary outcome was postoperative inflammatory response measured by white blood cell (WBC) count, neutrophil percentage (NP) and C-reactive protein (CRP).

RESULTS

The parameters of both groups of patients were comparable. The auto-group significantly outperformed the Allo-group in the following laboratory parameters: NKCC (%, E:T = 10:1) at day 2 [26.1 (Auto) vs 19.3 (Allo); P = 0.0025], NKCC (%, E:T = 5:1) at day 2 [20.0 (Auto) vs 17.3 (Allo); P = 0.0094], CD3+ (%) at day 2 [50.5 (Auto) vs 40.8 (Allo); P = 0.0233], CD4+ (%) at day 2 [41.2 (Auto) vs 26.3 (Allo); P = 0.0122], IgE (U/mL) at day 2 [157.8 (Auto) vs 319.8 (Allo); P = 0.0064].

CONCLUSION

Autotransfusion can safely replace allogeneic blood transfusion and reduce the damage of postoperative immune function after total hip arthroplasty.

Hip and Knee Osteoarthritis in Patients with Chronic Myeloproliferative Neoplasms: A Cross-Sectional Study

BACKGROUND

Osteoarthritis (OA) is a progressive degenerative disease with an inflammatory background. Chronic myeloproliferative neoplasms (MPN) are clonal hematopoietic disorders characterized by chronic inflammation and a tendency for connective tissue remodeling.

AIM

This study aimed to investigate the prevalence and associated risk factors of symptomatic OA (sOA) in MPN patients.

PATIENTS AND METHODS

A total of 100 consecutive MPN (39 essential-thrombocythemia, 34 polycythemia-vera, 27 myelofibrosis) patients treated in two community hematologic centers were cross-sectionally evaluated. Patients were required to have both symptoms attributable to hip and/or knee OA and radiographic confirmation to be considered as having sOA.

RESULTS

The prevalence of hip and/or knee sOA was significantly higher among MPN patients than the previously reported prevalence in the general population of similar age (61% vs. 22%, p < 0.001). Hip sOA was present in 50%, knee sOA in 51% and sOA of both localizations in 41% of patients. A high proportion of MPN patients had radiographic signs of hip OA (94%) and knee OA (98%) in the presence of attributable symptoms. Among the other factors, sOA was univariately associated with the presence of JAK2 mutation, myelofibrosis phenotype, older age, higher body weight, and higher MPN-SAF score (p < 0.050 for all analyses). In the multivariate analysis, older age (odds ratio = 1.19, 95% confidence interval-CI 1.06-1.33) and higher body weight (OR = 1.15, 95% CI 1.06-1.25) were recognized as independent risk factors for sOA. On the other hand, cytoreductive treatment was a protective factor for sOA (OR = 0.07, 95% CI 0.006-0.86).

CONCLUSIONS

The prevalence of sOA in MPN patients was higher than that in the general population and seems to correlate with older age, increased myeloproliferation and a higher inflammatory state. Whether cytoreductive treatment may postpone OA development in MPN patients warrants additional confirmation.

Effects of Non-Essential Amino Acids on Knee Joint Conditions in Adults: A Randomised, Double-Blind, Placebo-Controlled Trial

Joint problems impair performance during exercise and daily activities and influence quality of life. The present study aimed to examine the effects of a combination of six non-essential amino acids (6AA) on joint conditions in an adult population. A total of 50 participants aged between 20 and 64 years with joint discomfort but no diagnosed joint disorder were randomly and blindly assigned to a control or 6AA group. The 6AA group took 12 g of the non-essential amino acid formulation orally (4 g three times a day) and the control group took equivalent doses of a placebo. Each group maintained the daily dose for 12 weeks. Primary outcome measures were evaluated with the visual analogue scale (VAS), the Japanese Knee Osteoarthritis Measure (JKOM), and the Japanese Orthopaedic Association score (JOA). These tests were taken before the experiment began at 4 weeks and 12 weeks after the intervention. The results of the VAS indicated that 6AA improved joint pain, discomfort, and stiffness both during a resting state and during normal activity. Participants' scores on the JKOM and JOA also showed significant improvements in the group that had taken the 6AA supplement. These results demonstrate that 6AA improves symptoms of joint problems, such as pain, discomfort, stiffness, and difficulty in performing daily activities after 4 weeks of daily consumption.

Colchicine versus Physical Therapy in Knee Osteoarthritis

Background: The treatment of osteoarthritis remains a major challenge due to the unavailability of a disease-modifying medication and the limitations of current therapeutic perspectives, which mainly target the symptoms, not the disease itself. The purpose of our study is to compare the efficacy of colchicine treatment versus physical therapy. Methods: The study included 62 patients diagnosed with knee osteoarthritis (KOA) according to the American College of Rheumatology (ACR) criteria, hospitalized within the time frame of October 2020−March 2022 in the Department of Rehabilitation Medicine and Physical Therapy of the Emergency Clinical County Hospital of Craiova. The participants were randomly divided into two groups. The observation period was 16 weeks long. The first group (31 patients) received colchicine at a dosage of 1 mg/day together with analgesics (acetaminophen < 2 g/day), while the second group (31 patients) received analgesics (acetaminophen < 2 g/day) together with a 16-week plan of physiotherapy. Results: Group II, in which patients underwent physical therapy, demonstrated a statistically significant decrease in both left (p < 0.001) and right (p = 0.012) knee VAS and WOMAC (p = 0.038) scores at 16 weeks, compared to the group treated with colchicine. Regarding the MSUS examination at 16 weeks, there were no significant changes in the structural abnormalities and no improvement in cartilage aspect or thickness. Higher BMI was associated with higher WOMAC score (p = 0.012), but not with higher VAS score (p = 0.062). Cholesterol and triglyceride levels were associated with high WOMAC (p < 0.001; p = 0.021) and high VAS (p = 0.023; p < 0.001) scores. Conclusions: Our study monitored VAS and WOMAC scores in two groups of patients with KOA, showing that physical therapy is more effective than colchicine in reducing symptoms. We found no statistically significant difference in musculoskeletal ultrasound (MSUS) feature improvement during the 16-week study.

Degenerative joint disease induced by repeated intra-articular injections of monosodium urate crystals in rats as investigated by translational imaging

The objective of this work was to assess the consequences of repeated intra-articular injection of monosodium urate (MSU) crystals with inflammasome priming by lipopolysaccharide (LPS) in order to simulate recurrent bouts of gout in rats. Translational imaging was applied to simultaneously detect and quantify injury in different areas of the knee joint. MSU/LPS induced joint swelling, synovial membrane thickening, fibrosis of the infrapatellar fat pad, tidemark breaching, and cartilage invasion by inflammatory cells. A higher sensitivity to mechanical stimulus was detected in paws of limbs receiving MSU/LPS compared to saline-injected limbs. In MSU/LPS-challenged joints, magnetic resonance imaging (MRI) revealed increased synovial fluid volume in the posterior region of the joint, alterations in the infrapatellar fat pad reflecting a progressive decrease of fat volume and fibrosis formation, and a significant increase in the relaxation time T2 in femoral cartilage, consistent with a reduction of proteoglycan content. MRI also showed cyst formation in the tibia, femur remodeling, and T2 reductions in extensor muscles consistent with fibrosis development. Repeated intra-articular MSU/LPS injections in the rat knee joint induced pathology in multiple tissues and may be a useful means to investigate the relationship between urate crystal deposition and the development of degenerative joint disease.

Temporal relationship between osteoarthritis and comorbidities: a combined case control and cohort study in the UK primary care setting

Objective

To determine the burden of comorbidities in OA and their temporal relationships in the UK.

Methods

The Clinical Practice Research Datalink (CPRD) GOLD was used to identify people with incident OA and age, gender and practice matched non-OA controls from UK primary care. Controls were assigned the same index date as matched cases (date of OA diagnosis). Associations between OA and 49 individual comorbidities and multimorbidities (two or more comorbidities excluding OA) both before and after OA diagnosis were estimated, adjusting for covariates, using odds ratios (aORs) and hazard ratios (aHRs), respectively.

Results

During 1997–2017, we identified 221 807 incident OA cases and 221 807 matched controls. Of 49 comorbidities examined, 38 were associated with OA both prior to and following the diagnosis of OA and 2 (dementia and systemic lupus erythematosus) were associated with OA only following the diagnosis of OA. People with OA had a higher risk of developing heart failure [aHR 1.63 (95% CI 1.56, 1.71)], dementia [aHR 1.62 (95% CI 1.56, 1.68)], liver diseases [aHR 1.51 (95% CI 1.37, 1.67)], irritable bowel syndrome [aHR 1.51 (95% CI 1.45, 1.58)], gastrointestinal bleeding [aHR 1.49 (95% CI 1.39, 1.59)], 10 musculoskeletal conditions and 25 other conditions following OA diagnosis. The aOR for multimorbidity prior to the index date was 1.71 (95% CI 1.69, 1.74), whereas the aHR for multimorbidity after the index date was 1.29 (95% CI 1.28, 1.30).

Conclusions

People with OA are more likely to have other chronic conditions both before and after the OA diagnosis. Further study on shared aetiology and causality of these associations is needed.

Platelet Anti-Aggregant Activity and Bioactive Compounds of Ultrasound-Assisted Extracts from Whole and Seedless Tomato Pomace

Tomato paste production generates a residue known as tomato pomace, which corresponds to peels and seeds separated during tomato processing. Currently, there is an opportunity to use tomato pomace to obtain a functional extract with antithrombotic properties, such as platelet anti-aggregant activity. The aim of this study was to evaluate the yield and inhibitory activity of different extracts of tomato pomace on in vitro platelet aggregation, comparing this activity with commercial cardioprotective products, and quantify bioactive compounds. Aqueous or ethanolic/water (1:1) extracts of whole tomato pomace, seedless tomato pomace, tomato pomace supplemented with seeds (50% and 20%), and only seeds were obtained with different ultrasound-assisted extraction times. The inhibition of platelet aggregation was evaluated using a lumi-aggregometer. The quantification of bioactive compounds was determined by HPLC-MS. From 5 g of each type of tomato pomace sample, 0.023-0.22 g of a dry extract was obtained for the platelet aggregation assay. The time of sonication and extraction solvent had a significant role in platelet anti-aggregant activity of some extracts respect the control. Thus, the most active extracts decreased adenosine diphosphate (ADP)-induced platelet aggregation from 87 ± 6% (control) to values between 26 ± 6% and 34 ± 2% (p < 0.05). Furthermore, different ultrasound-assisted extraction conditions of tomato pomace fractions had varied concentration of flavonoids and nucleosides, and had an effect on extract yield.

Matrix Metalloproteinase-3 induces proteoglycan degradation in gouty arthritis model

BACKGROUND

Gout is an inflammatory arthritis resulting from precipitation of monosodium urate (MSU) crystals in joints and surrounding tissues. However, the mechanism underlying high levels of uric acid inducing gouty arthritis has not been clarified.

OBJECTIVE

The purpose was to investigate the role of Matrix Metalloproteinase-3 (MMP-3) in the development of gouty arthritis from hyperuricemia.

METHOD

MSU crystal-induced gouty arthritis model and chondrocytes were used to evaluate changes of MMP-3 levels. Western blot, qPCR and ELISA were performed to detect MMP-3, Tissue Inhibitors of Metalloproteinase-1 (TIMP-1) and A Disintegrin and Metalloproteinase with Thrombospondin Motifs-4 (ADAMTS-4) expressions in rabbit chondrocytes. Expression of proteoglycan was determined through toluidine blue staining. Concentrations of glycosaminoglycan, Interleukin-6 (IL-6), Interleukin-1β (IL-1β) and Tumor Necrosis Factor-α (TNF-α) in chondrocytes were assessed via ELISA kits. Concentration of uric acid in supernate was tested by Automatic Analyzer.

RESULTS

MMP-3 was significantly increased in rat serum, synovial fluid, cartilages and chondrocytes treated with high-level uric acid. Increased concentration of glycosaminoglycancould be observed in chondrocytes incubated with MMP-3, as well as the remarkable downregulation of proteoglycan expression. Furthermore, high-level uric acid contributed to the degradation of proteoglycan via the activation of MMP-3. IL-6, IL-1β and TNF-α concentrations were increased significantly in 35 °C compared to 37 °C with MMP-3 and high-level uric acid.

CONCLUSION

Our study showed that MMP-3 was enhanced by high levels of uric acid, which promoted proteoglycan degradation, and induced MSU crystallization in turn. A low temperature environment is an important factor in the development of gout.

Common Musculoskeletal Disorders in the Elderly: The Star Triad

Musculoskeletal disorders are debilitating conditions that significantly impair the state of health, especially in elderly subjects. A pathological triad of inter-related disorders that are highly prevalent in the elderly consists of the following main “components”: sarcopenia, tendinopathies, and arthritis. The aim of this review is to critically appraise the literature relative to the different disorders of this triad, in order to highlight the pathophysiological common denominator and propose strategies for personalized clinical management of patients presenting with this combination of musculoskeletal disorders. Their pathophysiological common denominator is represented by progressive loss of (focal or generalized) neuromuscular performance with a risk of adverse outcomes such as pain, mobility disorders, increased risk of falls and fractures, and impaired ability or disability to perform activities of daily living. The precise management of these disorders requires not only the use of available tools and recently proposed operational definitions, but also the development of new tools and approaches for prediction, diagnosis, monitoring, and prognosis of the three disorders and their combination.

Multifactor dimensionality reduction reveals a strong gene-gene interaction between STC1 and COL11A1 genes as a possible risk factor of knee osteoarthritis

Articular cartilage is an avascular tissue with a structure that allows it to support and cushion the overload of the surfaces in contact. It maintains its metabolic functions due to the contribution of different signaling pathways. However, several factors play a role in its deterioration, allowing to the development of osteoarthritis (OA), and one of the major factors is genetic. Our goal was to identify gene-gene interactions (epistasis) between five signaling pathways involved in the articular cartilage metabolism as possible indicators of OA risk. We applied the Multifactor-Dimensionality Reduction (MDR) method to identify and characterize the epistasis between 115 SNPs located in 73 genes related to HIF-1α, Wnt/β-catenin, cartilage extracellular matrix metabolism, oxidative stress, and uric acid transporters. Ninety three patients diagnosed with primary knee OA and 150 healthy controls were included in the study. Genotyping was performed with the OpenArray system, the statistical analysis was carried out with the STATA software v14, and epistasis was analyzed with the MDR software v3.0.2. The MDR analysis revealed that the best interaction model was between polymorphisms rs17786744 of the STC1 gene and rs2615977 of the COL11A1 gene, with an entropy value of 4.44%, CVC 8/10, OR 5.60, 95% CI 3.27-9.59, p < 0.0001. Under this interaction model, we identified high and low risk genotypes involved in OA development. Our results suggest complex interactions between STC1 and COL11A1 genes that might have an impact on genetic susceptibility to develop OA. Further studies are required to confirm it.

Common gene variants interactions related to uric acid transport are associated with knee osteoarthritis susceptibility

BACKGROUND

The presence of genetic variants in uric acid (UA) transporters can be associated with hyperuricemia, and therefore with an increased risk of monosodium urate (MSU) crystal precipitation. The inflammatory process triggered by these crystals leads to cartilage damage, which, in turn, could promote knee osteoarthritis (KOA).

OBJECTIVE

To determine whether genetic polymorphisms of the UA transporters and their interactions are associated with KOA.

MATERIALS AND METHODS

Two hundred forty-three unrelated Mexican-mestizo individuals were recruited for this case-control study. Ninety-three of them were KOA patients but without gout, and one hundred and fifty healthy individuals with no symptoms or signs of KOA were recruited as controls. Forty-one single-nucleotide polymorphisms (SNPs) involved in the UA transporters were genotyped with OpenArray technology in a QuantStudio 12K flex-System with both cases and controls.

RESULTS

After adjusting by age, gender, BMI, and ancestry, significant associations were found for eight SNPs: rs1260326 (GCKR), rs780093 (GCKR), rs17050272 (INHBB), rs1471633 (PDZK1), rs12129861 (PDZK1), rs7193778 (IGF1R), rs17786744 (STC1), and rs1106766 (R3HDM2). With respect to gene-gene interactions, the pairwise interactions of rs112129861 (PDZK1) and rs7193778 (IGF1R); rs17050272 (INHBB) and rs1106766 (R3HDM2); rs1106766 (R3HDM2) and rs780093 (GCKR); rs1260326 (GCKR) and rs17786744 (STC1); and rs17786744 (STC1) and rs1106766 (R3HDM2) make it possible to visualize the synergistic or antagonistic effect of their genotypes or alleles on KOA development.

CONCLUSIONS

Our preliminary results show that the common gene variants related to UA transport are associated with KOA in the Mexican population. Further studies must be carried out to corroborate it.

Proteoglycans isolated from the bramble shark cartilage show potential anti-osteoarthritic properties

Osteoarthritis (OA) causes articular cartilage destruction, initiating pain and inflammation in the joints, resulting in joint disability. Medications are available to manage these symptoms; however, their effects on the disease progression are limited. Loss of proteoglycans (PGs) was reported to contribute articular cartilage destruction in OA. Therapeutics approaches were previously studied in the animal models of OA. In the present study, we investigated the oral efficacy of four dosages of PGs (25 mg/kg, 50 mg/kg, 100 mg/kg and 200 mg/kg), isolated from the bramble shark cartilage, in an animal model of OA. Indomethacin was used as a bioequivalent formulation. Primarily, the mass spectrum analysis of the purified PGs obtained from bramble shark cartilage revealed the presence of two unique peptides including AGWLSDGSVR and LDGNPINLSK, that showed sequence similarity with aggrecan core-protein and epiphycan, respectively. The levels of C-reactive protein and uric acid in the OA rats were reduced when treated with PGs. Histopathology analysis displayed less cartilage erosion and neovascularization in OA rats treated with PGs. The X-ray imaging presented higher bone density with 200 mg/kg dosage of PG treatment in OA rats. The expressions of the inflammatory modulators including TNF-α, IL-1β, MMP13, NOS2, IL-10 and COX-2 were found to be moderated with PG treatment. In addition, PG treatment maintained the activities of antioxidant enzymes, including SOD and catalase in the joint tissues with a higher GSH content, in a dose-dependent manner. Taken together, our preliminary findings report the anti-osteoarthritic properties of PGs and recommend to evaluate its efficacy and safety in randomized trials.

Inflammation in osteoarthritis: is it time to dampen the alarm(in) in this debilitating disease?

Osteoarthritis (OA) is the most common joint disease that strongly reduces the quality of life in patients; However, no disease-modifying therapy is available. For a long time, OA was considered a non-inflammatory disease that was the result of 'wear-and-tear' and abnormal mechanics, and therefore many considered the term 'osteoarthritis' a misnomer. However, during the last decades the notion arose that inflammation is not only present in the majority of OA patients but, rather, actively involved in the progression of the disease. Influx of immune cells is observed in the synovium and a plethora of inflammatory mediators is present in tissues and fluids from OA patients. These mediators cause the production of degrading enzymes that break down the cartilage matrix, which is the main hallmark of OA. Alarmins, which belong to the group of danger signals, have been implicated in many inflammatory diseases. They are among the first factors to be released upon cell stress due to, for example, infection, damage and inflammation. They attract and activate cells of the immune system and therefore lie at the base of the inflammatory reaction. In this narrative review, an overview of the history of OA, the evolving concept of inflammation as important factor in the OA pathogenesis, and particularly the central role that alarmins play in the initiation and maintenance of the low-grade inflammatory response in OA, is provided. Moreover, the targeting of alarmins as a promising approach to dampen the inflammation in OA is highlighted.

Colchicine lack of effectiveness in symptom and inflammation modification in knee osteoarthritis (COLKOA): a randomized controlled trial

OBJECTIVES

Uric acid may activate an innate immune response in osteoarthritis (OA), contributing to disease pathology and progression. We evaluated the effectiveness of colchicine on pain and function in symptomatic knee OA (KOA) and the underlying mechanism of action.

METHODS

Colchicine effectiveness in symptoms and inflammation modification in knee osteoarthritis (COLKOA) was a double-blind, placebo-controlled, randomized trial comparing 16 weeks of treatment with 0.5 mg twice-daily oral colchicine to placebo for knee osteoarthritis (KOA). The primary endpoint was ≥30% improvement in total Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score at week 16. Secondary endpoints included improvement in pain (0-10 Likert scales); WOMAC pain; patient global assessment (0-100); physical function; the OARSI-OMERACT response; quality of life; and change in serum, urine, synovial fluid (SF) biomarkers of cartilage metabolism and inflammation, and plasma/SF colchicine concentrations.

RESULTS

Of 109 randomly assigned participants, 39% (95% confidence interval (CI) 27-52%) and 49% (95% CI 36-62%) in the colchicine and placebo arms respectively met the primary endpoint at study end (P = 0.284, odds ratio 0.66, 95% CI 0.31-1.41). No strong evidence of treatment differences was identified on clinical secondary endpoints. Treatment significantly reduced mean serum hs-CRP (P = 0.008) and SF CTXI (P = 0.002); treatment tended to reduce inflammatory markers (SF IL-6, IL8, TNFα, CD14 and IL-18), but these differences were not statistically significant.

CONCLUSION

Colchicine (0.5 mg twice-daily orally) reduced inflammation and high bone turnover biomarkers known to be associated with OA severity and progression risk, but did not reduce KOA symptoms over a 16-week study period. A longer-term study to evaluate for slow-acting disease modifying effects is warranted.

TRIAL REGISTRATION

The trial has been registered at clinicaltrials.gov as NCT02176460. Date of registration: June 26, 2014.