The pathogenesis of bone erosions in gouty arthritis

Dosing practices, pharmacokinetics, and effectiveness of allopurinol in gout patients receiving dialysis: a scoping review

Urate and oxypurinol, allopurinol's active metabolite, are predominantly eliminated by the kidneys. Therefore, optimising allopurinol dosing in patients on dialysis is challenging. This review explores allopurinol dosing practices, oxypurinol pharmacokinetics, and effectiveness in gout patients receiving haemodialysis or peritoneal dialysis (PD). Five databases and grey literature were searched. Studies on gout patients on allopurinol, receiving dialysis, and reporting dosing, pharmacokinetics, or effectiveness (reduction in urate and/or gout flares) were included. Abstract, full text screening and data extraction were done by two authors. Studies were grouped by dialysis modality. Eighteen studies were identified including 390 patients, most (n = 274, 70%) on haemodialysis with allopurinol administered after dialysis. The peritoneal dialytic clearance of oxypurinol (3.14 mL/min, n = 5) and urate (2.7-4 mL/min, n = 25) was similar. The haemodialytic clearance was 78-137 mL/min for oxypurinol (n = 21) and 80-165 mL/min for urate (n = 19). Allopurinol doses were higher in haemodialysis (100-600 mg/day) than PD (110-125 mg/day). Haemodialysis sessions decreased oxypurinol and urate concentrations by 39-57% (n = 30) and 56-71% (n = 6), respectively. Over time (1-230 days), urate concentrations in haemodialysis (n = 85) reduced by 14-41%. Target serum urate (< 0.36 mmol/L) was achieved in 61% (20/33) and 47% (13/28) of haemodialysis and PD patients, respectively. Gout flares decreased from 2 to 0.1 attacks/year in patients receiving dialysis (n = 79). Oxypurinol and urate clearance by haemodialysis was higher than PD, necessitating higher doses of allopurinol. POST dialysis allopurinol doses titrated to target urate are suggested. Future studies considering the impact of dialysis modality on allopurinol dose requirements are needed.

Spinal gout recovery with urate-lowering therapy: A case report

The occurrence of spinal gout resulting in erosion of the superior articular process in patients with low back pain is uncommon, potentially leading to misdiagnosis and inappropriate treatment. Urate-lowering therapy may be beneficial in improving joint destruction and bone erosion, as evidenced by our case.

Transdermal delivery of iguratimod and colchicine ethosome by dissolving microneedle patch for the treatment of recurrent gout

This study introduces a novel approach of repetitive modeling to simulate the pathological process of recurrent gout attacks in humans. This methodology addresses the instability issues present in rat models of gout, providing a more accurate representation of the damage recurrent gout episodes inflict on human skeletal systems. A soluble nanoneedle system encapsulating colchicine and iguratimod ethosomal formulations was developed. This system aims to modulate inflammatory cytokines and inhibit osteoclast activity, thereby treating inflammatory pain and bone damage associated with recurrent gout. Additionally, a comprehensive evaluation of the microneedles' appearance, morphology, mechanical properties, and penetration capability confirmed their effectiveness in penetrating the stratum corneum. Dissolution tests and skin irritation assessments demonstrated that these microneedles dissolve rapidly without irritating the skin. In vitro permeation studies indicated that transdermal drug delivery via these microneedles is more efficient and incurs lower drug loss compared to traditional topical applications. In vivo pharmacodynamic assessments conducted in animal models revealed significant analgesic and anti-inflammatory effects when both types of microneedles were used together. Further analyses, including X-ray imaging, hematoxylin and eosin (H&E) staining, Safranin-O/fast green staining, tartrate-resistant acid phosphatase staining, and quantification of osteoclasts, confirmed the bone-protective effects of the microneedle combination. In conclusion, the findings of this research underscore the potential of this novel therapeutic approach for clinical application in the treatment of recurrent gout.

Ultrasound Features in Gout: An Overview

The accurate diagnosis of gout frequently constitutes a challenge in clinical practice, as it bears a close resemblance to other rheumatologic conditions. An undelayed diagnosis and an early therapeutic intervention using uric acid lowering therapy (ULT) is of the utmost importance for preventing bone destruction, the main point of managing gout patients. Advanced and less invasive imaging techniques are employed to diagnose the pathology and ultrasonography (US) stands out as a non-invasive, widely accessible and easily reproducible method with high patient acceptability, enabling the evaluation of the full clinical spectrum in gout. The 2023 EULAR recommendations for imaging in diagnosis and management of crystal-induced arthropathies in clinical practice state that US is a fundamental imagistic modality. The guidelines underline its effectiveness in detecting crystal deposition, particularly for identifying tophi and the double contour sign (DCS). Its utility also arises in the early stages, consequent to synovitis detection. US measures of monosodium urate (MSU) deposits are valuable indicators, sensitive to change consequent to even short-term administration of ULT treatment, and can be feasibly used both in current daily practice and clinical trials. This paper aimed to provide an overview of the main US features observed in gout patients with reference to standardized imaging guidelines, as well as the clinical applicability both for diagnosis accuracy and treatment follow-up. Our research focused on summarizing the current knowledge on the topic, highlighting key data that emphasize gout as one of the few rheumatological conditions where US is recognized as a fundamental diagnostic and monitoring tool, as reflected in the most recent classification criteria.

Pathophysiology and Treatment of Gout Arthritis; including Gout Arthritis of Hip Joint: A Literature Review

Gout is triggered by the accumulation of uric acid in the body, leading to hyperuricemia. Genetic, metabolic, and environmental factors can influence this condition. Excessive uric acid buildup results in the formation of monosodium urate (MSU) crystals, which precipitate in specific areas of the body, including the joints, where they can cause symptoms of gout. While the acute and chronic symptoms of gout have been well-documented, diagnosis of gout affecting the hip joint poses significant challenges. The global incidence of gout, the most prevalent form of inflammatory arthritis, is on the rise. Evaluation of the clinical signs, laboratory results, and imaging results is generally required for diagnosis of gout in cases where MSU crystals have not been detected. Hyperuricemia is considered a primary cause of arthritis symptoms, and comprehensive guidelines for treatment are available. Therefore, the choice of medication is straightforward, and moderate effectiveness of treatment has been demonstrated. Gout is a chronic disease, requiring lifelong uric acid-lowering medications, thus application of a treatment strategy based on the target blood uric acid concentration is necessary. Consequently, cases of gout will likely be observed more frequently by hip surgeons in clinical scenarios in the future. The objective of this review is to provide an overview of the pathophysiology of gout and subsequently examine recent advances in diagnostic methods and therapeutic agents based on an understanding of its underlying mechanisms. In addition, literature on gout-related issues affecting the hip joint, providing a useful reference for hip surgeons is examined.

Time- and Concentration-Dependent Stimulation of Oxidative Stress in Chondrocytes by Intracellular Soluble Urate

BACKGROUND

Gout could result in irreversible bone erosion, and chondrocyte might be involved in the process. Increased soluble urate is the early stage of gout and is strongly oxidative.

OBJECTIVE

To explore the effect of intracellular urate on the oxidative status of chondrocytes.

METHODS

A chondrocyte model was used. Serial concentrations of exogenous urate were incubated with chondrocytes for increasing amounts of time. Reactive oxygen species (ROS), oxidant, and anti-oxidant molecules were measured with biochemical assays, rt-PCR, and western blot. A urate transport inhibitor and oxidative inhibitors were used to confirm the effect of exogenous urate.

RESULTS

All concentrations of exogenous urate stimulated the production of ROS in a time- and concentration-dependent manner, as well as oxidant molecules, including hydrogen peroxide (H2O2), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, nitric oxide (NO) inducible nitric oxide synthase (iNOS), and these effects, could be inhibited by oxidant inhibitors. However, anti-oxidant molecules, including acidic leucine-rich nuclear phosphoprotein-32A (ANP32A), ataxia-telangiectasia mutated (ATM), heme oxygenase-1 (HO-1), and the transcription factor nuclear factor erythroid 2 (NF-E2)-related (Nrf2), was decreased by high concentrations of exogenous urate after prolonged incubation, but not by low to medium concentrations of exogenous urate. By inhibiting soluble urate trafficking, benzbromarone significantly suppressed the effect of urate stimulus on the oxidant and anti-oxidant molecules.

CONCLUSION

Intracellular soluble urate could regulate chondrocyte redox balance in a time and concentration-dependent manner, and would be a target for regulating and protecting chondrocyte function in the early gout stage.

Chinese herbal compound Huangqin Qingrechubi capsule reduces lipid metabolism disorder and inflammatory response in gouty arthritis via the LncRNA H19/APN/PI3K/AKT cascade

CONTEXT

Gouty arthritis (GA) is a characteristically inflammatory disease often associated with lipid metabolism disorder. Huangqin Qingrechubi capsule (HQC) has been used for the treatment of GA.

OBJECTIVE

To explore the mechanism of HQC in the treatment of GA.

MATERIALS AND METHODS

A total of 30 GA patients (GA group) and 30 healthy subjects [normal control (NC) group] were recruited. The GA group was treated with HQC (3.6 g/d) for 10 days. Lipid metabolism and inflammation indexes were detected. Five herbal names of HQC, or 'gouty arthritis', 'hyperlipidemia' and 'inflammation' were used as key words to search related databases for network pharmacological analysis. Subsequently, GA-fibroblast-like synoviocytes (FLSs) were stimulated with GA-peripheral blood mononuclear cells (PBMCs) (3:1) and treated with HQC drug-containing serum (20%). RT-qPCR, Western blot, and ELISA were conducted to further explore the mechanism of HQC in improving GA.

RESULTS

In clinical observation, HQC decreased the expression of lncRNA H19 and IL-1β, and increased the expression of adiponectin (APN) and IL-4 in the GA group (about half). Through network pharmacology, the PI3K/AKT signaling pathway was identified. Cell experiments showed that HQC treatment reduced the viability of GA-FLSs (49.61%), up-regulated the expression of IL-4 (155.18%), IL-10 (165.13%), and APN (31.24%), and down-regulated the expression of lncRNA H19 (33.70%), IL-1β (64.70%), TNF-α (78.32%), p-PI3K (48.80%), and p-AKT (53.48%).

DISCUSSION AND CONCLUSIONS

HQC improved lipid metabolism disorder and inflammatory response of GA by regulating the lncRNA H19/APN/PI3K/AKT. Maintaining the stability of lipid metabolism may be an effective way to alleviate GA.

Mechanism of ShuiJingDan in Treating Acute Gouty Arthritis Flares Based on Network Pharmacology and Molecular Docking

Purpose

This study examined the underlying mechanisms of SJD's anti-inflammatory and analgesic effects on acute GA flares.

Methods

This study used pharmacology network and molecular docking methods. The active ingredients of ShuiJingDan (SJD) were obtained from the Traditional Chinese Medicine Systems Pharmacology Analysis Platform (TCMSP), and the relevant targets of GA were obtained from the Online Mendelian Inheritance in Man (OMIM) database and Therapeutic Target Database (TTD). The core drug group-target-disease Venn diagram was formed by crossing the active ingredients of SJD and the relevant targets. Gene Ontology (GO) analysis was conducted for functional annotation, DAVID was used for Kyoto Encyclopedia of Genes, and Genomes pathway enrichment analysis, and R was used to find the core targets. The accuracy of SJD network pharmacology analysis in GA treatment was verified by molecular docking simulations. Finally, a rat GA model was used to further verify the anti-inflammatory mechanism of SJD in the treatment of GA.

Results

SJD mainly acted on target genes including IL1B, PTGS2, CXCL8, EGF, and JUN, as well as signal pathways including NF-κB, Toll-like receptor (TLR), IL-17, and MAPK. The rat experiments showed that SJD could significantly relieve ankle swelling, reduce the local skin temperature, and increased the paw withdrawal threshold. SJD could also reduce synovial inflammation, reduced the concentrations of interleukin-1β (IL-1β), IL-8, and COX-2 in the synovial fluid, and suppressed the expression of IL1B, CXCL8, and PTGS2 mRNA in the synovial tissue.

Conclusion

SJD has a good anti-inflammatory effect to treat GA attacks, by acting on target genes such as IL-1β, PTGS2, and CXCL8.

Mechanisms and rationale for uricase use in patients with gout

Xanthine oxidase inhibitors such as allopurinol and febuxostat have been the mainstay urate-lowering therapy (ULT) for treating hyperuricaemia in patients with gout. However, not all patients receiving oral ULT achieve the target serum urate level, in part because some patients cannot tolerate, or have actual or misconceived contraindications to, their use, mainly due to comorbidities. ULT dosage is also limited by formularies and clinical inertia. This failure to sufficiently lower serum urate levels can lead to difficult-to-treat or uncontrolled gout, usually due to poorly managed and/or under-treated gout. In species other than humans, uricase (urate oxidase) converts urate to allantoin, which is more soluble in urine than uric acid. Exogenic uricases are an exciting therapeutic option for patients with gout. They can be viewed as enzyme replacement therapy. Uricases are being used to treat uncontrolled gout, and can achieve rapid reduction of hyperuricaemia, dramatic resolution of tophi, decreased chronic joint pain and improved quality of life. Availability, cost and uricase immunogenicity have limited their use. Uricases could become a leading choice in severe and difficult-to-treat gout as induction and/or debulking therapy (that is, for lowering of the urate pool) to be followed by chronic oral ULT. This Review summarizes the evidence regarding available uricases and those in the pipeline, their debulking effect and their outcomes related to gout and beyond.

Qingre Huazhuo Jiangsuan Decoction promotes autophagy by inhibiting PI3K/AKT/mTOR signaling pathway to relieve acute gouty arthritis

ETHNOPHARMACOLOGICAL RELEVANCE

Gout belongs to the category of "arthralgia syndrome" in traditional Chinese medicine. It is believed that gout is caused by stagnation of blood stasis, heat, and turbid toxin. Qingre Huazhuo Jiangsuan Decoction (QHJD) is a traditional Chinese medicine prescription developed from the classic Chinese medicine prescription Simiao powder to clear heat, remove turbidity, reduce acid, and reduce inflammation. Now Traditional Chinese Medicine (TCM) physicians often apply it to treat acute gouty arthritis (AGA). However, the mechanism of QHJD in relieving acute gouty arthritis is still unclear, and further research is needed.

AIM OF THE STUDY

Here, we aim to explore the potential mechanism of QHJD in relieving acute gouty arthritis.

MATERIALS AND METHODS

Acute gouty arthritis model was established by injecting monosodium urate (MSU) suspension into knee joint. The pathological state of synovial tissue in each group was evaluated by hematoxylin-eosin (HE) staining. The level of TNF-α, IL-6, and IL-1β were detected by enzyme-linked immunosorbent assay (ELISA). qRT-PCR was used to detect the mRNA expression of NLRP3, ATG5, ATG7, PI3K, AKT, and mTOR. The protein expression of LC3II/I, p62, ULK1, P-ULK1, Beclin-1, PI3K, AKT, mTOR, P-PI3K, P-AKT, and P-mTOR were detected by Western blot.

RESULTS

(1) The level of autophagy protein (mRNA) was significantly up-regulated in QHJD group and rapamycin, while the expression of autophagy protein (mRNA) was significantly downregulated in the 3-methyladenoenoic acid (3 MA) group; (2) QHJD and rapamycin significantly inhibited PI3K/AKT/mTOR pathway, while 3 MA group activated this pathway. (3) It was worth noting that after treatment with QHJD and rapamycin, the inflammatory pathological state of AGA synovial tissue was significantly reduced with the activation of the autophagy gene in knee synovial tissue, and the inhibition of PI3K/AKT/mTOR pathway.

CONCLUSIONS

This research revealed that QHJD activates autophagy by inhibiting PI3K/AKT/mTOR pathway, thereby relieving acute gouty arthritis.

Mechanism Investigation of Wuwei Shexiang Pills on Gouty Arthritis via Network Pharmacology, Molecule Docking, and Pharmacological Verification

Background

Gout is a common crystal-related arthritis caused by the deposition of monosodium urates (MSU). Tibetan medicine Wuwei Shexiang Pills (WSP) has been demonstrated to exhibit anti-inflammatory, antihyperuricemia, and antigout activities. However, the underlying mechanism is unknown.

Objectives

To explore the mechanisms of Wuwei Shexiang Pills on gouty arthritis via network pharmacology, molecule docking, and pharmacological verification.

Methods

The ingredients and targets of WSP were obtained by searching and screening in BATMAN-TCM and SwissADME. The targets involving the gout were acquired from public databases. The shared targets were put onto STRING to construct a PPI network. Furthermore, Metascape was applied for the GO and KEGG enrichment analysis to predict the biological processes and signaling pathways. And molecular docking was performed to validate the binding association between the key ingredients and the relative proteins of TNF signaling. Based on the serum pharmacology, the predicted antigout mechanism of WSP was validated in MSU-induced THP-1 macrophages. The levels of inflammatory cytokines and mRNA were measured by ELISA and qRT-PCR, respectively, and MAPK, NF-κB, and NLRP3 signaling-associated proteins were determined by western blot and immunofluorescence staining.

Results

48 bioactive ingredients and 165 common targets were found in WSP. The data showed that 5-Cis-Cyclopentadecen-1-One, 5-Cis-Cyclotetradecen-1-One, (-)-isoshyobunone, etc. were potential active ingredients. TNF signaling, HIF-1 signaling, and Jak-STAT signaling were predicted to be the potential pathways against gout. The molecule docking analysis found that most ingredients had a high affinity for p65, NLRP3, IL-1β, TNF-α, and p38. The data from in vitro experiment showed that WSP suppressed the production and gene expression of inflammatory cytokines. Furthermore, WSP could inhibit the activation of MAPK, NF-κB, and NLRP3 signaling pathways.

Conclusion

Our finding suggested that the antigout effect of WSP could be achieved by inhibiting MAPK, NF-κB, and NLRP3 signaling pathways. WSP might be a candidate drug for gouty treatment.

The combination of sodium alginate and chlorogenic acid enhances the therapeutic effect on ulcerative colitis by the regulation of inflammation and the intestinal flora

Chlorogenic acid (CA) and sodium alginate (SA) each have good therapeutic effects on ulcerative colitis (UC) owing to their antioxidant and anti-inflammatory activity. This study aimed to investigate the effects of CA alone and in combination with SA on inflammatory cells and UC mice. In the Lipopolysaccharide (LPS)-induced RAW 264.7 inflammatory cell model, Nitric oxide (NO) and interleukin-6 (IL-6) levels were significantly lower after treatment with CA plus SA than with CA alone. In the DSS-induced UC mouse model, compared with CA alone, CA plus SA showed a better ability to alleviate weight loss, reduce the disease activity index (DAI), improve the colonic mucosa, reduce the expression of inflammatory factors in the serum and myeloperoxidase (MPO) in colonic tissue, increase superoxide dismutase (SOD) levels, protect the intestinal mucosa and regulate the abundance of Actinobacteriota, Lactobacillus, Bifidobacterium, Bacteroides, Subdoligranulum and Streptococcus. Thus, CA plus SA can improve the therapeutic efficacy of CA in UC by regulating inflammatory factors, oxidative stress, and the intestinal flora and by protecting ulcerative wounds. These findings broaden our understanding of the role of the combination of SA and CA in enhancing the effects of CA on UC and provide strategies for prevention and treatment.

Identification of Interleukin-1-Beta Inhibitors in Gouty Arthritis Using an Integrated Approach Based on Network Pharmacology, Molecular Docking, and Cell Experiments

Background

This study aimed to investigate the molecular mechanism of Tongfengding capsule (TFDC) in treating immune-inflammatory diseases of gouty arthritis (GA) and interleukin-1-beta (IL-1β) inhibitors by using network pharmacology, molecular docking, and cell experiments.

Methods

In this study, the compounds of TFDC and the potential inflammatory targets of GA were obtained from Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP), Online Mendelian Inheritance in Man (OMIM), and GeneCards databases. The TFDC-GA-potential targets interaction network was accomplished by the STRING database. The TFDC-active compound-potential target-GA network was constructed using Cytoscape software. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were used to further explore the GA mechanism and therapeutic effects of TFDC. Quantitative real-time PCR (qPCR) was used to verify whether the TFDC inhibited IL-1β in GA. Molecular docking technology was used to analyze the optimal effective compounds from the TFDC for docking with IL-1β.

Result

133 active compounds and 242 targets were screened from the TFDC, and 25 of the targets intersected with GA inflammatory targets, which were considered as potential therapeutic targets. Network pharmacological analysis showed that the TFDC active compounds such as quercetin, stigmasterol, betavulgarin, rutaecarpine, naringenin, dihydrochelerythrine, and dihydrosanguinarine had better correlation with GA inflammatory targets such as PTGS2, PTGS1, NOS2, SLC6A3, HTR3A, PPARG, MAPK14, RELA, MMP9, and MMP2. The immune-inflammatory signaling pathways of the active compounds for treating GA are IL-17 signaling pathway, TNF signaling pathway, NOD-like receptor signaling pathway, NF-kappa B signaling pathway, Toll-like receptor signaling pathway, HIF-1 signaling pathway, etc. The TFDC reduced IL-1β mRNA expression in GA by qPCR. Molecular docking results suggested that rutaecarpine was the most appropriate natural IL-1β inhibitor.

Conclusion

Our findings provide an essential role and bases for further immune-inflammatory studies on the molecular mechanisms of TFDC and IL-1β inhibitors development in GA.

Factors secreted by monosodium urate crystal-stimulated macrophages promote a proinflammatory state in osteoblasts: a potential indirect mechanism of bone erosion in gout

BACKGROUND

Tophi are lesions commonly present at sites of bone erosion in gout-affected joints. The tophus comprises a core of monosodium urate (MSU) crystals surrounded by soft tissue that contains macrophages and other immune cells. Previous studies found that MSU crystals directly reduce osteoblast viability and function. The aim of the current study was to determine the indirect, macrophage-mediated effects of MSU crystals on osteoblasts.

METHODS

Conditioned medium from the RAW264.7 mouse macrophage cell line cultured with MSU crystals was added to the MC3T3-E1 mouse osteoblastic cell line. Conditioned medium from the THP-1 human monocytic cell line cultured with MSU crystals was added to primary human osteoblasts (HOBs). Matrix mineralization was assessed by von Kossa staining. Gene expression was determined by real-time PCR, and concentrations of secreted factors were determined by enzyme-linked immunosorbent assay.

RESULTS

In MC3T3-E1 cells cultured for 13 days in an osteogenic medium, the expression of the osteoblast marker genes Col1a1, Runx2, Sp7, Bglap, Ibsp, and Dmp1 was inhibited by a conditioned medium from MSU crystal-stimulated RAW264.7 macrophages. Mineral staining of MC3T3-E1 cultures on day 21 confirmed the inhibition of osteoblast differentiation. In HOB cultures, the effect of 20 h incubation with a conditioned medium from MSU crystal-stimulated THP-1 monocytes on osteoblast gene expression was less consistent. Expression of the genes encoding cyclooxygenase-2 and IL-6 and secretion of the proinflammatory mediators PGE2 and IL-6 were induced in MC3T3-E1 and HOBs incubated with conditioned medium from MSU crystal-stimulated macrophages/monocytes. However, inhibition of cyclooxygenase-2 activity and PGE2 secretion from HOBs indicated that this pathway does not play a major role in mediating the indirect effects of MSU crystals in HOBs.

CONCLUSIONS

Factors secreted from macrophages stimulated by MSU crystals attenuate osteoblast differentiation and induce the expression and secretion of proinflammatory mediators from osteoblasts. We suggest that bone erosion in joints affected by gout results from a combination of direct and indirect effects of MSU crystals.

Genetic polymorphisms and decreased protein expression of ABCG2 urate transporters are associated with susceptibility to gout, disease severity and renal-overload hyperuricemia

Gout is a common crystal induced disease of high personal and social burden, characterised by severe arthritis and comorbidity if untreated. Impaired function of ABCG2 transporter is causative in gout and may be responsible for renal-overload type hyperuricemia. Despite its importance, there is limited information on how clinical parameters correlate with protein expression and that with genetic changes. Urate and clinical parameters of 78 gouty patients and healthy controls were measured among standardised circumstances from a Hungarian population. ABCG2 membrane expression of red blood cells was determined by flow cytometry-based method and SNPs of this protein were analysed by TaqMan-based qPCR. The prevalence of ABCG2 functional polymorphisms in gouty and control patients were 32.1 and 13.7%, respectively. Most common SNP was Q141K while one sample with R236X, R383C and the lately described M71V were found in the gouty population. These polymorphisms showed strong linkage with decreased protein expression while the latter was also associated with higher fractional urate excretion (FUE) and urinary urate excretion (UUE). This study firstly evaluated ABCG2 protein expression in a clinically defined gouty population while also proving its associations between ABCG2 genetic changes and renal-overload hyperuricemia. The paper also highlighted relations between ABCG2 SNPs, gout susceptibility and disease severity characterised by an early onset disease with frequent flares and tophi formation.

RvD1 disrupts nociceptor neuron and macrophage activation, and neuroimmune communication reducing pain and inflammation in gouty arthritis in mice

BACKGROUND AND PURPOSE

Gouty arthritis is characterised by an intense inflammatory response to monosodium urate crystals (MSU), which induces severe pain. Current therapies are often ineffective in reducing gout-related pain. Resolvin D1 (RvD1) is a specialised pro-resolving lipid mediator with anti-inflammatory and analgesic proprieties. In this study, we evaluated the effects and mechanisms of action of RvD1 in an experimental mouse model of gouty arthritis, an aim that was not pursued previously in the literature.

EXPERIMENTAL APPROACH

Male mice were treated with RvD1 (intrathecally or intraperitoneally) before or after intraarticular stimulation with MSU. Mechanical hyperalgesia was assessed using an electronic von Frey aesthesiometer. Leukocyte recruitment was determined by knee joint wash cell counting and immunofluorescence. IL-1β production was measured by ELISA. Phosphorylated NF-kB and apoptosis-associated speck-like protein containing CARD (ASC) were detected by immunofluorescence, and mRNA expression was determined by RT-qPCR. CGRP release was determined by EIA and immunofluorescence. MSU crystal phagocytosis was evaluated by confocal microscopy.

KEY RESULTS

RvD1 inhibited MSU-induced mechanical hyperalgesia in a dose- and time-dependent manner by reducing leukocyte recruitment and IL-1β production in the knee joint. Intrathecal RvD1 reduced the activation of peptidergic neurons and macrophages as well as silenced nociceptor to macrophage communication and macrophage function. CGRP stimulated MSU phagocytosis and IL-1β production by macrophages. RvD1 downmodulated this phenomenon directly by acting on macrophages, and indirectly by inhibiting CGRP release and CGRP-dependent activation of macrophages.

CONCLUSIONS AND IMPLICATIONS

This study reveals a hitherto unknown neuro-immune axis in gouty arthritis that is targeted by RvD1.

Immunosuppression by piperine as a regulator of the NLRP3 inflammasome through MAPK/NF-κB in monosodium urate-induced rat gouty arthritis

Background and Aim: Gouty arthritis is a metabolic disorder involving monosodium urate (MSU) crystal deposition as a key initiator of acute inflammation. Dysregulation of the nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain-containing protein 3 (NLRP3) inflammasome is associated with the pathogenesis of gout through the maturation of interleukin-1β. Piperine (PIP) is a phytochemical with an anti-inflammatory activity that has the potential as an alternative treatment for gout. In this study, we examined the effect of PIP in immunosuppression of gout inflammation through the regulation of the NLRP3 inflammasome. Materials and Methods: An in silico study was done by pharmacodynamic modeling of PIP in suppressing MSU-induced inflammation through disruption of the NLRP3 inflammasome. In vivo tests, including inflammatory assessment, histopathology, cytology, estimation of lipid peroxidation index, and detection of systemic inflammatory reactants, were performed on two groups using preventive and curative protocols. Results: In silico studies of molecular docking demonstrated the activity of PIP as a competitive inhibitor of the mitogen-activated protein kinases/nuclear factor-kappaB axis, upstream of the NLRP3 inflammasome. Analysis of gout models with curative and preventive protocols revealed the immunosuppression activity of PIP by reducing inflammatory symptoms, inhibiting tophus formation resulting from NETosis, reducing cartilage erosion, inhibiting leukocyte exudation, suppressing lipid peroxidation index, and inhibiting the production of C-reactive protein. Conclusion: The results demonstrate the activity of PIP as an immunosuppressant in gout flare. These findings indicate the potential of PIP as a candidate for prophylactic and therapeutic agent for the treatment of gouty arthritis.

3β,23-Dihydroxy-12-ene-28-ursolic Acid Isolated from Cyclocarya paliurus Alleviates NLRP3 Inflammasome-Mediated Gout via PI3K-AKT-mTOR-Dependent Autophagy

Gout is regarded as a painful inflammatory arthritis induced by the deposition of monosodium urate crystals in joints and soft tissues. Nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome-mediated IL-1β production plays a crucial role in the pathological process of gout. Cyclocarya paliurus (CP) tea was found to have an effect on reducing the blood uric acid level of people with hyperuricemia and gout. However, its medicinal ingredients and mechanism for the treatment of gout are still unclear. Thus, this study was designed to investigate the effects of the active triterpenoids isolated from C. paliurus on gout and explore the underlying mechanism. The results showed that compound 2 (3β,23-dihydroxy-12-ene-28-ursolic acid) from C. paliurus significantly decreased the protein expression of IL-1β, caspase-1, pro-IL-1β, pro-caspase-1, and NLRP3. Furthermore, the production of ROS in the intracellular was reduced after compound 2 treatment. However, ROS agonist rotenone remarkably reversed the inhibitory effect of compound 2 on the protein expression of NLRP3 inflammasome. Additionally, the expression level of LC3 and the ratio of LC3II/LC3I were increased, but the expression level of p62 was suppressed by compound 2 whereas an autophagy inhibitor 3-methyladenine (3-MA) significantly abolished the inhibitory effects of compound 2 on the generation of ROS and the protein expression of NLRP3 inflammasome. Moreover, compound 2 could ameliorate the expression ratio of p-PI3K/PI3K, p-AKT/AKT, and p-mTOR/mTOR. Interestingly, mTOR activator MHY-1485 could block the promotion effect of compound 2 on autophagy regulation and inhibitory effect of compound 2 on induction of ROS and IL-1β. In conclusion, these findings suggested that compound 2 may effectively improve NLRP3 inflammasome-mediated gout via PI3K-AKT-mTOR-dependent autophagy and could be further investigated as a potential agent against gout.

Ethyl acetate extract of the Musa nana flower inhibits osteoclastogenesis and suppresses NF-κB and MAPK pathways

Banana flowers are consumed as a vegetable and traditionally used for managing several health problems including joint pain, a symptom of bone loss. Osteoclasts are key effector cells responsible for bone loss. Some flavonoids in banana flowers, such as quercetin and quercitrin, have been shown to be able to inhibit osteoclastogenesis. Whether banana flowers can inhibit osteoclast formation is unknown. In this study, we prepared the ethyl acetate fraction (FFE-EA) of an ethanolic extract of fresh flowers of Musa nana. Using UPLC-MS/MS analyses, 76 polyphenols were identified in FFE-EA. In RANKL-stimulated RAW264.7 macrophages, FFE-EA inhibited osteoclastogenesis and osteoclastic bone resorption. Mechanistic studies revealed that FFE-EA suppressed NF-κB and MAPK pathways, and lowered mRNA levels of osteoclast formation/function-related genes. These findings suggest that flowers of M. nana could be a source for formulating functional food that benefits bone health.

Quantitative assessment of crystal dissolution in gout during urate-lowering therapy with computer-aided MicroPure imaging: a cohort study

Background

To evaluate whether MicroPure imaging, an ultrasound (US) image-processing technique with computer-aided analysis, can quantitatively detect crystal dissolution during urate-lowering therapy (ULT) in gout.

Methods

This was a prospective study of gout patients requiring ULT. The first metatarsophalangeal joints were examined using US and MicroPure before and after 3 months of ULT. Elementary lesions of gout, including the double contour sign (DCS), aggregates, tophi, erosion, and other US features were recorded at baseline and 3 months. MicroPure imaging features were automatically calculated by a self-developed software. Patients were divided into goal-achieved and goal-not-achieved groups according to their urate levels at 3 months. The US and MicroPure imaging features of the two groups were analyzed at baseline and 3 months.

Results

A total of 55 consecutive patients were enrolled (25: goal-achieved group; 30: goal-not-achieved group). US findings demonstrated that the power Doppler signal grade decreased at 3 months, regardless of the group (both P<0.05). From baseline to 3 months, tophi size and the DCS reduced in the goal-achieved group (both P<0.05), while the US aggregate features showed no difference (P=0.250). However, on the MicroPure imaging, the number and density of aggregates at 3 months decreased in the goal-achieved group (both P<0.05). There were no significant changes at 3 months in any of the MicroPure imaging features in the goal-not-achieved group (all P>0.05).

Conclusions

In comparison with B-mode US, computer-aided MicroPure imaging can sensitively and quantitatively detect aggregate dissolution during effective ULT after only 3 months of treatment.

Prevalence of and risk factors for hallux rigidus: a cross-sectional study in Japan

Background

Hallux rigidus (HR) is a common osteoarthritis of the first metatarsophalangeal joint. However, the epidemiology and risk factors of this pathology have yet to be clarified.

Methods

We have been conducting cohort studies among individuals over 50 years old every 2 years since 1997. This study analyzed data from the 7th to 10th checkups in 2009, 2011, 2013, and 2015. We investigated the prevalence of HR and its risk factors in a total of 604 individuals (mean age, 67.1 ± 6.4 years; 208 men, 396 women). Radiographic HR was defined as Hattrup and Johnson classification grade 1 or higher. Knee osteoarthritis (KOA) was scored according to the Kellgren-Lawrence grading system. Radiographic KOA was defined as grade 2 or higher. Cases with a hallux valgus (HV) angle of 20° or higher were defined as showing HV. Statistical analyses were performed using the Kruskal-Wallis test, Fisher’s exact test, logistic regression modeling, and the Cochran-Armitage trend test. All p-values presented are two-sided and values of p < .05 were considered statistically significant.

Results

The prevalence of HR was 26.7% (161/604). Rates of grade 0, 1, 2, and 3 HR according to the Hattrup and Johnson classification were 73.3% (443/604), 16.4% (99/604), 8.0% (48/604), and 2.3% (14/604), respectively. Overall ratio of symptomatic HR was 8.1%. Univariate analysis revealed KOA, gout attack (GA), and HV as significantly associated with HR. The same factors were confirmed as independent risk factors for HR in multivariate analysis. All parameters were significantly associated with HR. Odds ratios of KOA, HV, and GA for HR were 1.73, 3.98, and 3.86, respectively. The presence or absence of KOA was significantly associated with severity of HR.

Conclusions

This study revealed that the prevalence of HR in the elderly (≥50 years) was 26.7%. KOA, HV, and GA were independent risk factors for HR. KOA was associated with severity of HR.

Regulation of crystal induced inflammation: current understandings and clinical implications

Introduction: Accumulation of abnormal crystals in the body, derived from endogenous or exogenous materials can drive a wide spectrum of inflammatory disease states. It is well established that intra-articular deposition of monosodium urate (MSU) and calcium pyrophoshate (CPP) crystals contributes to joint destruction through pro-inflammatory processes.Areas covered: This review will focus on current understanding and recent novelty about the mechanisms and the clinical implications of the inflammation induced by MSU and CPP crystals.Expert opinion: Advances in molecular biology reveal that at the base of the inflammatory cascade, stimulated by MSU or CPP crystals, there are many complex cellular mechanisms mainly involving the NLRP3 inflammasome, the hallmark of autoinflammatory syndromes. The extensive studies carried out through in vitro and in vivo models along with a better clinical definition of the disease has led to an optimized use of existing drugs and the introduction of novel therapeutic strategies. In particular, the identification of IL-1 as the most important target in gout and pseudogout has made it possible to expand the pharmacological indications of anti-IL-1 biological drugs, opening new therapeutic perspectives for patients.

Minimally Invasive Embedding of Saturated MSU Induces Persistent Gouty Arthritis in Modified Rat Model

Introduction

Animal models are valid for in vivo research on the pathophysiological process and drug screening of gout arthritis. Intra-articular injection of monosodium urate (MSU) is the most common method, while stable MSU deposition enveloped by inflammatory cells was rarely reported.

Objective

To develop a modified gouty arthritis rat model characterized by intra-articular MSU deposition and continuous joint pain with a minimally invasive method.

Method

A total of twenty-four rats were randomly allocated into six groups. Three intervention groups of rats received intra-articular MSU embedment. Sham groups received pseudosurgeries with equal normal saline (NS). Gross parameters and pathological features of synovium harvested from anterior capsule were estimated. Mechanical pain threshold tests were conducted over a 96-hour period postoperatively. Moreover, quantitative immunofluorescence was conducted to assess tissue inflammation.

Result

After MSU embedding, rats got more persistent arthritic symptoms as well as tissue MSU deposition. More significant synovial swelling was detected in the MSU group compared to sham groups (P < 0.025). Behavioral tests showed that the embedding of MSU resulted in prolonged mechanical hyperalgesia during 2 hours to 96 hours postoperatively (P < 0.05). MSU depositions enveloped by inflammatory cells that express IL-1β and TNF-α were detected in embedding groups. Quantitative immunofluorescence suggested that the frequencies of MSU interventions upregulated expression of proinflammatory factors including IL-1β and TNF-α (P < 0.05).

Conclusion

A minimally invasive method was developed to establish modified rat model of intra-articular MSU deposition. This model was proved to be a simple reproducible method to mimic the pathological characteristics of persistent gouty arthritis.

Hyperuricemia and Cardiovascular Risk

As the prevalence of hyperuricemia (elevated uric acid levels in the blood) increases, the relationship between serum uric acid levels and cardiovascular risk has garnered increased interest. Several studies have highlighted that elevated uric acid levels are likely tied to increased cardiovascular disease risk. Specifically, the presence of hyperuricemia is well-established to contribute to the onset of gout (an inflammatory condition characterized by painful/swollen joints). Several studies have shown that the risk of developing gout is strongly associated with the degree of hyperuricemia. In this review, we will provide insight into the association between gout and cardiovascular disease risk. It is also important to gain insight into the pathophysiology of gout to understand the contributions to cardiovascular disease risk as well as improve diagnosis and target treatment more effectively. An interdisciplinary approach for gout management and areas for further investigation will be discussed in this review.

Effect of canakinumab on clinical and biochemical parameters in acute gouty arthritis: a meta-analysis

BACKGROUND

Targeted anti-IL-1β therapy may be a valuable option for the management of gouty arthritis. The present meta-analysis has evaluated the effect of canakinumab, an anti-IL-1β monoclonal antibody in gouty arthritis.

METHODS

A standard meta-analysis protocol was developed and after performing a comprehensive literature search in MEDLINE, Cochrane, and International Clinical Trial Registry Platform (ICTRP), reviewers assessed eligibility and extracted data from three relevant articles. A random-effects model was used to estimate the pooled effect size as the mean difference in Visual Analouge Scale (VAS) score, serum hsCRP, serum Amyloid A, and risk ratio for global assessment between the groups. Quality assessment was done using the risk of bias assessment tool and summary of findings was prepared using standard Cochrane methodology with GradePro GDT.

RESULTS

Treatment with canakinumab showed a mean reduction of VAS score by 14.59 mm [95% CI - 19.42 to - 9.77], serum hsCRP by 15.36 mg/L [95% CI 1.62-29.11], serum Amyloid A by 67.18 mg/L [95% CI 17.06-117.31], and improvement in patient global assessment (RR = 1.478; 95% CI 1.29-1.67) and physician global assessment (RR = 1.44; 95% CI 1.28-1.61). The probability that future studies may have a mean difference in VAS score less than zero has been calculated to be 27.3% using a cumulative distribution function (CDF) calculator.

CONCLUSION

This meta-analysis shows the beneficial effect of canakinumab over triamcinolone by reducing VAS score, serum hsCRP, serum amyloid A, and improvement in global assessments in acute gouty arthritis.

Anti-inflammatory Effects and Mechanisms of Rhein, an Anthraquinone Compound, and Its Applications in Treating Arthritis: A Review

Inflammation is a defensive response of living tissues to damaging agents, which exists in two forms, acute inflammation and chronic inflammation, and chronic inflammation is closely related to arthritis. Currently, the commonly prescribed anti-inflammatory medications are greatly limited by high incidence of gastrointestinal erosions in the clinical applications. Rhein, a bioactive constituent of anthraquinone, exhibits excellent anti-inflammatory activities and therapeutic effects on arthritis with less gastrointestinal damages. Although there are numbers of studies on anti-inflammatory effects and mechanisms of rhein in the last few decades, to the best of our knowledge, only a few review articles pay attention to the interactive relationships of rhein on multiple inflammatory signaling pathways and cellular processes from a comprehensive perspective. Herein, we summarized anti-inflammatory effects and mechanisms of rhein and its practical applications in the treatment of arthritis, thereby providing a reference for its basic researches and clinical applications.

Treatment of atypical gouty arthritis of the hip using total hip arthroplasty: A case report

RATIONALE

Gout and gouty arthritis typically involve peripheral and monoarticular joints, especially the first metatarsophalangeal joint and knees. Hip involvement in patients with gout is rare, and its diagnosis is very difficult, especially in the late stages of the disease. Total hip arthroplasty could be a surgical treatment for atypical gouty arthritis of the hip; however, few cases have been reported.

PATIENT CONCERNS

We reported an uncommon case of a 74-year-old man without typical symptoms of hip gout arthritis whom was misdiagnosed as having avascular necrosis of the femoral head.

DIAGNOSES

Clinical examination and imaging revealed bilateral avascular necrosis of the femoral head. However, the final pathology report revealed left hip gout arthritis.

INTERVENTIONS

The patient underwent left total hip arthroplasty and was followed up for 3years.

OUTCOMES

The outcome was favorable. The function of the left hip was almost normal.

LESSONS

Our case indicated the difficulty of the diagnosis of hip gout arthritis. Due to the lower rates of hip gout arthritis and lack of typical clinical examination, it is easy to misdiagnose. Furthermore, surgical treatment for the late stage of hip gout arthritis has not previously been reported. In our case, total hip arthroplasty proved to be a good option.

The prevalence and characteristics of osseous erosions associated with parameniscal cysts on knee MRI

OBJECTIVES

To determine the prevalence and characteristics of erosions associated with parameniscal cysts (PMCs) and to evaluate the profile of the associated meniscal tears MATERIALS AND METHODS: PACS database was reviewed for knee MRI scans performed over a 5-year period identifying those with PMCs in patients aged 18 years and above. The scans with PMCs were evaluated for the presence of associated osseous erosions. These erosions and PMCs were then analyzed.

RESULTS

The search revealed 6773 knee MRI examinations, of which 555 had confirmed PMCs. There were 7 PMC-associated erosions for a prevalence of 1.3% (95% CI 0.6, 2.6). All erosions involved the proximal tibia. Three of 7 erosions had underlying marrow edema, and 4 out of 7 had an overhanging margin. The mean dimension of all PMCs was 13 mm (SD = 11). The mean dimension of PMCs associated with erosions was 38 mm (SD = 22), while that of PMCs without erosions was 12 mm (SD = 10) (P < 0.001, Wilcoxon rank sum test). Ninety-three percent (95% CI 90.5, 94.8) of PMCs had associated meniscal tears, most commonly of the horizontal type (57%). All PMCs with underlying erosions were associated with meniscal tears, most commonly complex type tears (5/7).

CONCLUSION

Erosions can rarely be associated with contiguous parameniscal cysts (PMCs). These cysts are significantly larger compared with those without underlying erosions.

Musculoskeletal ultrasound in the Differential Diagnosis of Gouty Arthritis and Rheumatoid Arthritis

Objective:

To explore the role of musculoskeletal ultrasound (MSUS) in the differential diagnosis of gouty arthritis (GA) and rheumatoid arthritis (RA) and to analyze the ultrasound imaging features of the two diseases.

Methods:

A retrospective study was carried out. A total of 66 patients who had been admitted to The First Medical Center of Chinese PLA General Hospital from May 2018 to March 2019 were enrolled. Among them, 34 patients were diagnosed with RA and were included in the RA group; 32 patients were diagnosed with gouty arthritis and were included in the GA group. The imaging features of musculoskeletal ultrasound were compared between the two groups of patients.

Results:

A total of 34 patients were included in the RA group, including 17 males and 17 females. A total of 32 patients were included in the GA group, including 14 males and 18 females. There were no significant differences in gender composition, age, and duration of disease between the two groups (P>0.05). In the RA group, there were joint bone erosions with a clear boundary in seven cases and with a blurred boundary in 27 cases; synovial hyperplasia was observed in 27 cases, and point-like hyperechoic masses were observed in four cases. In the GA group, there were joint bone erosions with a clear boundary in 27 cases and with a blurred boundary in five cases; synovial hyperplasia was observed in four cases, tophus was observed in 23 cases, point-like hyperechoic masses were observed in 27 cases, and the tram-track sign was observed in 23 cases. The differences in bone erosion boundaries (c2=26.854, P<0.01), synovial hyperplasia (c2=29.631, P<0.01), tophus (P<0.01), point-like hyperechoic mass (c2=33.095, P<0.01), and tram-track sign (P<0.01) were statistically significant between the two groups of patients. In the RA group, blood flow signaling was Grade 0 in one case, Grade-I in five cases, Grade-II in 14 cases, and Grade-III in 14 cases. In the GA group, blood flow signaling was Grade 0 in 26 cases, Grade-I in three cases, Grade-II in three cases, and Grade-III in zero cases. The difference in the synovial blood flow signaling between the two groups of patients was statistically significant (c2=34.323, P<0.01).

Conclusions:

MSUS has certain diagnostic value in the differentiation of GA and RA. Moreover, the two conditions have their own ultrasound imaging features.

Prevalence and Factors Associated With Bone Erosion in Patients With Gout

OBJECTIVE

To determine the prevalence, distribution, and factors associated with bone erosion detectable by ultrasound in patients with gout.

METHODS

Ultrasound scans were performed in 980 patients with gout, and bone erosion was detected. The prevalence and distribution of bone erosion in gout patients were calculated. Both clinical variables and ultrasound signs were entered into a multivariate logistic regression analysis to clarify the factors associated with bone erosion in patients with gout.

RESULTS

Bone erosion was found in 431 (44.0%) of the 980 patients with gout, and in 338 (78.4%) of these patients, the bone erosion was found in the first metatarsophalangeal (MTP) joint. A multivariable logistic regression analysis showed that age, duration of gout, the existence of tophi, ultrasound-detected synovial hypertrophy, and joint effusion were independently associated with bone erosion. A tophus was the most powerful factor associated with bone erosion, with an odds ratio (OR) of 4.218 (95% confidence interval 3.092-5.731). The risk for bone erosion also increased as the number of tophi increased (P < 0.001). However, after stratifying the size of tophi, the ORs did not increase significantly (P = 0.206).

CONCLUSION

A high percentage of gout patients had bone erosions; the first MTP joint was the most frequently involved site. Age, duration of gout, tophi, and synovial hypertrophy were factors associated with bone erosion in gout patients. The number of tophi, but not their size, was strongly associated with bone erosion in patients with gout.

[Lesion clearance combined with Ilizarov technique for treatment of tophi in first metatarsophalangeal joint with bone defect]

Objective

To evaluate the effectiveness of lesion clearance combined with Ilizarov technique for the treatment of tophi in first metatarsophalangeal (MTP) joint with bone defect.

Methods

Between July 2016 and June 2018, 14 cases of tophi in the first MTP joint with bone defect were treated by lesion clearance combined with Ilizarov technique. There were 12 males and 2 females. The average age was 39.3 years (range, 22-60 years). The disease duration ranged from 5 to 15 years, with an average of 11.2 years. The tophi volume ranged from 2.5 cm×2.7 cm×2.2 cm to 5.2 cm×2.9 cm×2.4 cm. The X-ray films showed that the length of the bone defect ranged from 2.0 to 4.6 cm, with an average of 3.4 cm. Preoperative visual analogue scale (VAS) score was 7.6±0.9; American Orthopaedic Foot and Ankle Society (AOFAS) score was 47.5±4.3; short-form 36 health survey scale (SF-36) score was 79.7±4.7.

Results

The incision primarily healed in 13 patients after operation. The skin necrosis at the edge of the incision occurred in 1 patient and recovered after symptomatic treatment. All 14 patients were followed up 12-16 months, with an average of 13.6 months. X-ray films showed that the first metatarsal column defects were repaired. The time of bone extension ranged from 2 to 6 weeks, with an average of 3.6 weeks. The time of bone healing ranged from 9 to 16 weeks, with an average of 11.2 weeks. During follow-up, no complication such as nerve, blood vessel, or tendon injury, needle tract infection, or stress fracture occurred. At last follow-up, VAS score was 1.4±0.5, AOFAS score was 86.6±4.8, and SF-36 score was 89.1±3.3, all of which were superior to preoperative scores, with significant differences ( t=22.532, P=0.000; t=22.702, P=0.000; t=6.124, P=0.000).

Conclusion

Lesion clearance combined with Ilizarov technique is a safe and effective method for the treatment of tophi in the first MTP joint with bone defect.

Plantar Fasciitis in Diabetic Foot Patients: Risk Factors, Pathophysiology, Diagnosis, and Management

Plantar fasciitis (PF) is a common degenerative disorder and a frequent cause of heel pain, mostly affecting patients in their fourth and fifth decades. Diabetic patients are particularly at risk due to the presence of common risks and co-morbidities such as obesity or a sedentary lifestyle. The diagnosis of PF is mainly clinical. Imaging is not recommended for the initial approach. The initial management is conservative and should include physiotherapy, off-loading, stretching exercises, and nonsteroidal anti-inflammatory drugs. Glucocorticoid injections or surgery is an option at a later stage in recalcitrant cases. The overall management of PF does not differ between patients with diabetic foot problems and non-diabetic patients, although the details can differ. This narrative review summarizes the state of the art in terms of the risk factors, pathophysiology, diagnosis, assessment, and management of PF in diabetic patients.

Relationship between urate within tophus and bone erosion according to the anatomic location of urate deposition in gout: A quantitative analysis using dual-energy CT volume measurements

The aim of this study was to measure the urate volume within tophus and bone erosion volume using dual-energy computed tomography in patients with tophaceous gout. Furthermore, our study aims to quantitatively analyze the relationship between monosodium urate (MSU) crystal deposition and bone erosion according to the anatomic location of urate deposition.Seventy-seven subjects with chronic gout were positively identified for the presence of urate deposition. Only 27 subjects identified for the presence of urate in contact with bone erosion were included in this study. The urate volumes and associated erosion volumes were measured. The relationships between urate within tophus and bone erosion were separately analyzed according to the anatomic location of urate deposition.Twenty-seven subjects were all male (100%) with a median (interquartile range, IQR) age of 52 (45-61) years. From all the subjects, 103 tophi depositions were identified in contact with bone erosion, including 58/103 tophi that contained an intraosseous component and 45/103 nonintraosseous tophi. Tophi containing intraosseous components were larger than nonintraosseous tophi (urate volume: median [IQR] 45.64 [4.79-250.89] mm vs 19.32 [6.97-46.71] mm, P = .035) and caused greater bone erosion (erosion volume: 249.03 [147.08-845.33] mm vs 69.07 [32.88-111.24] mm, P < .001). Almost all erosion volumes were larger than urate volumes in nonperiarticular tophi, in contrast to most erosion volumes, which were less than urate volumes in the tophi that contained a periarticular component (odds ratio, 95% confidence interval: 74.00, 14.70-372.60; P < .001). Urate volume and erosion volume demonstrated positive correlations in intraosseous tophi, intraosseous-intra-articular-periarticular tophi, and intraosseous-intra-articular tophi (rs = 0.761, rs = 0.695, rs = 0.629, respectively, P < .05).MSU crystal deposition shows a promoting effect on the development of bone erosions in varying degrees, associated with the location of MSU crystals deposited in the joints. The intraosseous tophi contribute the most to bone erosions, followed by intra-articular tophi, and periarticular tophi.

Interaction of the p.Q141K Variant of the ABCG2 Gene with Clinical Data and Cytokine Levels in Primary Hyperuricemia and Gout

Gout is an inflammatory arthritis influenced by environmental risk factors and genetic variants. The common dysfunctional p.Q141K allele of the ABCG2 gene affects gout development. We sought after the possible association between the p.Q141K variant and gout risk factors, biochemical, and clinical determinants in hyperuricemic, gouty, and acute gouty arthritis cohorts. Further, we studied the correlation of p.Q141K allele and levels of pro-/anti-inflammatory cytokines. Coding regions of the ABCG2 gene were analyzed in 70 primary hyperuricemic, 182 gout patients, and 132 normouricemic individuals. Their genotypes were compared with demographic and clinical parameters. Plasma levels of 27 cytokines were determined using a human multiplex cytokine assay. The p.Q141K variant was observed in younger hyperuricemic/gout individuals (p = 0.0003), which was associated with earlier disease onset (p = 0.004), trend toward lower BMI (p = 0.056), and C-reactive protein (CRP, p = 0.007) but a higher glomerular filtration rate (GFR, p = 0.035). Levels of 19 cytokines were higher, mainly in patients with acute gouty arthritis (p < 0.001), irrespective of the presence of the p.Q141K variant. The p.Q141K variant influences the age of onset of primary hyperuricemia or gout and other disease-linked risk factors and symptoms. There was no association with cytokine levels in the circulation.

Omnipresence of inflammasome activities in inflammatory bone diseases

The inflammasomes are intracellular protein complexes that are assembled in response to a variety of perturbations including infections and injuries. Failure of the inflammasomes to rapidly clear the insults or restore tissue homeostasis can result in chronic inflammation. Recurring inflammation is also provoked by mutations that cause the constitutive assembly of the components of these protein platforms. Evidence suggests that chronic inflammation is a shared mechanism in bone loss associated with aging, dysregulated metabolism, autoinflammatory, and autoimmune diseases. Mechanistically, inflammatory mediators promote bone resorption while suppressing bone formation, an imbalance which over time leads to bone loss and increased fracture risk. Thus, while acute inflammation is important for the maintenance of bone integrity, its chronic state damages this tissue. In this review, we discuss the role of the inflammasomes in inflammation-induced osteolysis.

Central Tendon-Splitting Approach and Double Row Suturing for the Treatment of Insertional Achilles Tendinopathy

BACKGROUND

To assess the clinical outcomes of central tendon-splitting approach and double row anchor suturing for the treatment of insertional Achilles tendinopathy.

METHODS

28 patients (28 feet) diagnosed with insertional Achilles tendinopathy were included in this study. The inclusions were symptom of hindfoot pain around the insertion of the Achilles tendon, radiographic demonstration of calcification, or degeneration of the Achilles tendon, showing no symptom improvement even after standard nonsurgical treatment for more than six months. The X-ray revealed that patients had obvious posterior superior calcaneal exostosis with the possibility of friction with the Achilles tendon or intratendinous calcification. Surgical correction by the central tendon-splitting approach and double row Achilles tendon suturing was performed. The ankles were immobilized with plaster for four weeks postoperatively. The American Orthopaedic Foot and Ankle Society (AOFAS) score and visual analogue score (VAS) were assessed preoperatively and at 2 years postoperatively. At final follow-up, the Manchester-Oxford Foot Questionnaire (MOXFQ) as patient-reported outcome measures (PROMs) was also evaluated.

RESULTS

No complication, including postoperative wound infection and tendon rupture, was not found. All the patients resumed their daily activities with no high level of daily activities, such as jumping and jogging after 6 weeks postoperatively. 27 patients were available for follow-up for at least 2 years, while only one patient was lost to follow-up. At postoperative 2 years, the postoperative AOFAS score increased significantly, while the VAS score decreased statistically when compared with preoperative values. At final follow-up, 24 patients had complete alleviation of pain, whereas the remaining 3 patients complained of mild heel pain after walking for a long time. The MOXFQ score showed obvious relief of previous symptoms for all included cases.

CONCLUSIONS

Central tendon-splitting approach and double row Achilles tendon suture provide excellent intraoperative visual field, larger tendon-bone contact area, and stronger pullout strength and, thus, facilitate early rehabilitation. It can be a safe and effective method for the treatment of insertional Achilles tendinopathy.

LncRNA-Jak3:Jak3 coexpressed pattern regulates monosodium urate crystal-induced osteoclast differentiation through Nfatc1/Ctsk expression

LncRNA transcripts have been emerged as gene regulators through transcriptional and posttranscriptional regulation. Monosodium urate monohydrate (MSU) elicits inflammatory response and a critical regulator of bone erosion in gout. The aim of this study is to clarify the pro-osteogenic role of LncRNA in MSU-induced osteoclast differentiation. We performed microarray analysis to identify stage specific expressions of LncRNA and mRNA during osteoclast differentiation in RAW264.7 cells. Among the 314 pairs of LncRNA-mRNA coexpressed patterns in the osteoclast lineage, 22 pairs revealed to have inflammatory function. Importantly, LncRNA-Jak3 and Jak3 co-expression patterns were significantly upregulated in the osteoclasts. In specific, Jak3 contributes to MSU-induced osteoclasts differentiation by positively regulating expression of the osteoclast factor, nuclear factor of activated T-cells 1 (Nfatc1). Mechanistically, LncRNA-Jak3-mediated Nfatc1 activation upregulated cathepsin K (Ctsk) expressions. LncRNA-Jak3 knockdown abolished formation of MSU-induced mature osteoclasts. In addition, we found that gout patients showed increased levels of LncRNA-Jak3 in the mononuclear cells. Our data demonstrate that the critical functional role of LncRNA-Jak3 in osteoclast differentiation via Jak3/Nfatc1/Ctsk axis. Finally, characterization of these regulatory networks is likely to reveal novel drug targets and opportunities for therapeutic intervention in bone erosion.

Leptin Increases Particle-Induced Osteolysis in Female ob/ob Mice

Particles generated from wear of prosthesis joint bearing surfaces induce inflammation-mediated periprosthetic bone resorption (osteolysis). Morbidly obese leptin-deficient ob/ob mice are resistant to polyethylene particle-induced bone loss, suggesting that leptin, a hormone produced by adipocytes that circulates in concentrations proportional to total body adiposity, increases osteolysis. To confirm that particles induce less osteolysis in leptin-deficient mice after controlling for cold stress (room temperature)-induced bone loss, ob/ob mice on a C57BL/6 (B6) background and colony B6 wildtype (WT) mice housed at thermoneutral temperature were randomized to control or particle treatment groups (N = 5/group). Polyethylene particles were implanted over calvaria and mice sacrificed 2 weeks later. Compared to particle-treated WT mice, particle-treated ob/ob mice had lower osteolysis score, less infiltration of immune cells, and less woven bone formation. To determine the role of leptin in particle-induced osteolysis, ob/ob mice were randomized into one of 4 groups (n = 6-8/group): (1) control, (2) particles, (3) particles + continuous leptin (osmotic pump, 6 μg/d), or (4) particles + intermittent leptin (daily injection, 40 μg/d). Leptin treatment increased particle-induced osteolysis in ob/ob mice, providing evidence that the adpiokine may play a role in inflammation-driven bone loss. Additional research is required to determine whether altering leptin levels within the physiological range results in corresponding changes in polyethylene-particle-induced osteolysis.

Ultrasonographic Features of Lower-Limb Joints in Gout: Which Joints and Clinical Characteristics Would Provide More Information for Diagnosis?

OBJECTIVE

This observational cross-sectional study evaluated the distribution of ultrasound (US) features of lower-limb joints and the risk factors of tophus in gout patients.

METHODS

We examined 588 joints including the bilateral knee, ankle, and first metatarsophalangeal (MTP) joints in 98 gout patients by US between March to August in 2017. The distribution of double-contour (DC), tophus, aggregates, synovitis, effusion and erosion in different joint, course, and age groups were investigated by Cochran Q and χ test. The risk factors of tophus were analyzed using logistic regression method.

RESULTS

Double-contour was most commonly observed in the knee (p = 0.005). Tophus, aggregates, synovitis, and erosion were mostly detected in the first MTP (p < 0.001, p = 0.01, p = 0.001, p < 0.001, respectively). The prevalence rates of DC, tophus, and erosion in patients with a longer course were significantly higher (p = 0.029, p = 0.002, p < 0.001, respectively). Older patients had more detectable tophus and erosion than younger patients (p = 0.028, p = 0.021). Patients of older age (odds ratio [OR], 3.83; 95% confidence interval [CI], 1.27-11.48), with frequent attacks (OR, 3.80; 95% CI, 1.10-13.15), and with longer course (OR, 6.52; 95% CI, 1.37-30.96) had higher risks of tophus.

CONCLUSIONS

Most signs were detected by US in the first MTP, except that DC was most commonly observed in the knees. Patients of older age with frequent attacks and longer course may experience higher risks for tophus. Comprehensive assessment of the lower limbs, particularly the knee and first MTP, can significantly help diagnosis.

Differentiating the acute phase of gout from the intercritical phase with ultrasound and quantitative shear wave elastography

OBJECTIVES

To evaluate the value of ultrasound (US) in differentiating the acute phase of gout from the intercritical phase, particularly using shear wave elastography (SWE).

METHODS

57 gout patients were prospectively enrolled and divided into acute phase and intercritical phase groups. The patients underwent US and SWE examinations for the first metatarsophalangeal joints with the same protocol. Maximum synovial thickness was measured. US features were reviewed by two radiologists independently. The maximum (E_max) and mean (E_mean) elastic moduli of synovium were calculated. Diagnostic performances of US, SWE and combined US and SWE were evaluated.

RESULTS

US findings demonstrated that the colour Doppler flow signal grade in the acute phase was higher than that in the intercritical phase (p = 0.001), whereas no differences were found for B-mode US features between the two groups (all p > 0.05). For SWE, E_max and E_mean were significantly higher in the intercritical phase than in the acute phase (both p < 0.001). The areas under the receiver operating characteristic curve (AUROCs) were 0.494-0.553 for B-mode US, 0.735 for colour Doppler US (CDUS), 0.887 for E_max and 0.882 for E_mean. The combination of CDUS and SWE increased the AUROC, sensitivity and accuracy significantly in comparison with CDUS alone (all p < 0.001). However, the combined set did not show stronger diagnostic performance in comparison with SWE alone.

CONCLUSION

SWE increases the diagnostic performance in differentiating the acute phase of gout from the intercritical phase in comparison with conventional US.

KEY POINTS

• Colour Doppler flow signal grade is higher in acute phase of gout than in intercritical phase. • SWE demonstrates that synovium stiffness is higher in intercritical phase of gout than in acute phase. • SWE increases diagnostic performance in differentiating acute phase of gout from intercritical phase in comparison with conventional US.

Role of inflammasome regulation on immune modulators

Inflammatory responses are essential in eliminating harmful substrates from damaged tissue and inducing recovery. Several cytokines participate in and facilitate this response. Certain cytokines such as interleukin (IL)-1β and IL-18 are initially produced in precursor form in response to toll-like receptor (TLR) ligands and undergo maturation by inflammasomes, which are cytosolic multi-protein complexes containing nucleotide-binding oligomerization domain (NOD)-containing protein 2-like receptors (NLRs). Immune modulators targeting inflammasomes have been investigated to control inflammatory diseases such as metabolic syndrome. However, most immune modulators possessing anti-inflammasome properties attenuate production of other cytokines, which are essential for host defense. In this review, we analyzed the effect of anti-inflammasome agents on the production of cytokines which are not regulated by inflammasome and involving in initial immune responses. As a result, the inflammasome inhibitors are put into three categories: non-effector, stimulator, or inhibitor of cytokine production. Even the stimulator of cytokine production ameliorated symptoms resulting from inflammasome activation in mouse models. Thus, we suggest ideal immune modulators targeting inflammasomes in order to enhance cytokine production while inhibiting cytokine maturation.

Inflammation in gout: mechanisms and therapeutic targets

The acute symptoms of gout are triggered by the inflammatory response to monosodium urate crystals, mediated principally by macrophages and neutrophils. Innate immune pathways are of key importance in the pathogenesis of gout, in particular the activation of the NLRP3 inflammasome, which leads to the release of IL-1β and other pro-inflammatory cytokines. The orchestration of this pro-inflammatory cascade involves multiple intracellular and extracellular receptors and enzymes interacting with environmental influences that modulate the inflammatory state. Furthermore, the resolution of inflammation in gout is becoming better understood. This Review highlights recent advances in our understanding of both positive and negative regulatory pathways, as well as the genetic and environmental factors that modulate the inflammatory response. Some of these pathways can be manipulated and present novel therapeutic opportunities for the treatment of acute gout attacks.

Gout: An old disease in new perspective - A review

Gout is a picturesque presentation of uric acid disturbance. It is the most well understood and described type of arthritis. Its epidemiology is studied. New insights into the pathophysiology of hyperuricemia and gouty arthritis; acute and chronic allow for an even better understanding of the disease. The role of genetic predisposition is becoming more evident. The clinical picture of gout is divided into asymptomatic hyperuricemia, acute gouty arthritis, intercritical period, and chronic tophaceous gout. Diagnosis is based on laboratory and radiological features. The gold standard of diagnosis is identification of characteristic MSU crystals in the synovial fluid using polarized light microscopy. Imaging modalities include conventional radiography, ultrasonography, conventional CT, Dual-Energy CT, Magnetic Resonance Imaging, nuclear scintigraphy, and positron emission tomography. There is remarkable progress in the application of ultrasonography and Dual-Energy CT which is bound to influence the diagnosis, staging, follow-up, and clinical research in the field. Management of gout includes management of flares, chronic gout and prevention of flares, as well as management of comorbidities. Newer drugs in the pharmacological armamentarium are proving successful and supplement older ones. Other important points in its management include patient education, diet and life style changes, as well as cessation of hyperuricemic drugs.

Images in clinical medicine: Tophi

Tophi (plural of tophus, Latin for “stone”) are stone-like deposits of monosodium urate in the soft tissues, synovial tissues, or in bones near the joints. They are pathognomonic for gout, the most common inflammatory arthritis in the United States, with an estimated lifetime prevalence of 4%. It is usually the end result of loss of the balance between uric acid production and excretion. It can be found anywhere in the body especially in areas of friction or trauma. It is usually painless and rarely to present as the initial manifestation of gout. It is diagnosed mainly clinically. Imaging is mainly used to assess the complication like bony erosions. The American College of Rheumatology (ACR) guidelines currently indicate that urate-lowering therapy should be initiated in patients with the presence of tophi visible on examination or imaging (ACR Evidence A). First-line therapy for urate lowering remains the xanthine oxidase inhibitor allopurinol. The ACR currently recommends colchicine, 0.6 mg (or 0.5 mg) once or twice daily, or low dose NSAIDs should be continued to reduce gout flare incidence for six months after resolution of the tophus. Daily prednisone ≤10 mg has been endorsed as an acceptable second-line prophylactic agent.

Abbreviations: ACR: American College of Rheumatology; NSAID: non-steroidal anti-inflammatory drug

Crystal arthritides - gout and calcium pyrophosphate arthritis : Part 2: clinical features, diagnosis and differential diagnostics

Gout develops in four stages beginning with an asymptomatic increase in blood levels of uric acid. An acute gout attack is an expression of an underlying inflammatory process, which in the course of time is self-limiting. Without therapy monosodium urate crystals remain in the synovial fluid and synovial membrane and trigger more acute attacks. In the course of the disease monosodium urate crystals form deposits (tophi) leading in severe forms to irreversible joint deformities with loss of functionality. In 20% of cases gout leads to involvement of the kidneys. Overproduction of uric acid can cause nephrolithiasis. These stones can be composed of uric acid or calcium phosphate. Another form of kidney disease caused by gout is uric acid nephropathy. This is a form of abacterial chronic inflammatory response with deposition of sodium urate crystals in the medullary interstitium. Acute obstructive nephropathy is relatively rare and characterized by renal failure due to uric acid precipitation in the tubules because of rapid cell lysis that occurs, for example, with chemotherapy. There is a causal interdependence between the occurrence of hyperuricemia and hypertension. Uric acid activates the renin-angiotensin-aldosterone (RAA) system and inhibits nitric oxide (NO) with the possible consequence of a rise in systemic vascular resistance or arteriolar vasculopathy; however, uric acid is also an apparently independent risk factor for atherosclerosis. In contrast to young patients, the diagnosis of an acute gout attack in the elderly can be a challenge for the physician. Polyarticular manifestations and obscure symptoms can make it difficult to differentiate it from rheumatoid arthritis and calcium pyrophosphate deposition disease (CPPD). Aspiration of synovial fluid with visualization of urate crystals using compensated polarized light microscopy is the gold standard for diagnosis of acute gout. Moreover, analysis of synovial fluid enables a distinction from septic arthritis by Gram staining and bacterial culture. Soft tissue ultrasonography is useful to detect affected synovial tissue and monosodium urate crystals within the synovial fluid. Involvement of bone occurs relatively late in the disease so that x‑ray images are not useful in the early stages but might be helpful in differential diagnostics. Dual energy computed tomography (CT) and magnetic resonance imaging (MRI) can be used for certain indications.