Monosodium Urate Deposits Research Articles

Transcriptomic Analysis of THP-1 Cells Exposed by Monosodium Urate Reveals Key Genes Involved in Gout.

Gout is a common inflammatory arthritis, which is mainly caused by the deposition of monosodium urate (MSU) in tissues. Transcriptomics was used to explore the pathogenesis and treatment of gout in our work. The objective of the study was to analyze and validate potential therapeutic targets and biomarkers in THP-1 cells that were exposed to MSU. THP-1 cells were exposed to MSU. The inflammatory effect was characterized, and RNA-Seq analysis was then carried out. The differential genes obtained by RNA-Seq were analyzed with gene expression omnibus (GEO) series 160170 (GSE160170) gout-related clinical samples in the GEO database and gout-related genes in the GeneCards database. From the three analysis approaches, the genes with significant differences were verified by the differential genes' transcription levels. The interaction relationship of long non-coding RNA (lncRNA) was proposed by ceRNA network analysis. MSU significantly promoted the release of IL-1β and IL-18 in THP-1 cells, which aggravated their inflammatory effect. Through RNA-Seq, 698 differential genes were obtained, including 606 differential mRNA and 92 differential `LncRNA. Cross-analysis of the RNA-Seq differential genes, the GSE160170 differential genes, and the gout-related genes in GeneCards revealed a total of 17 genes coexisting in the tripartite data. Furthermore, seven differential genes-C-X-C motif chemokine ligand 8 (CXCL8), C-X-C motif chemokine ligand 2 (CXCL2), tumor necrosis factor (TNF), C-C motif chemokine ligand 3 (CCL3), suppressor of cytokine signaling 3 (SOCS3), oncostatin M (OSM), and MIR22 host gene (MIR22HG)-were verified as key genes that analyzed the weight of genes in pathways, the enrichment of inflammationrelated pathways, and protein-protein interaction (PPI) nodes combined with the expression of genes in RNA-Seq and GSE160170. It is suggested that MIR22HG may regulate OSM and SOCS3 through microRNA 4271 (miR-4271), OSM, and SOCS3m; CCL3 through microRNA 149-3p (miR-149-3p); and CXCL2 through microRNA 4652-3p (miR-4652-3p). The potential of CXCL8, CXCL2, TNF, CCL3, SOCS3, and OSM as gout biomarkers and MIR22HG as a therapeutic target for gout are proposed, which provide new insights into the mechanisms of gout biomarkers and therapeutic methods.

Epigenomic Reprogramming in Gout

Gout is a crystal-induced arthropathy in which monosodium urate (MSU) crystals precipitate within joints as a result of persistent hyperuricemia and elicit an inflammatory response. An intriguing aspect is the occurrence of gout in only 10–15% of hyperuricemic individuals, suggesting the presence of additional risk factors. Although MSU crystal deposition is widely recognized as the cause of gout flares, the variability in initiating the inflammatory response to hyperuricemia and MSU deposition is not well understood. Several studies bring up-to-date information about the environmental and genetic influences on the progression towards clinical gout. Elevated urate concentrations and exposure to different external factors precipitate gout flares, highlighting the potential involvement of epigenetic mechanisms in gouty inflammation. A better understanding of the alteration of the epigenetic landscape in gout may provide new perspectives on the dysregulated inflammatory response. In this review, we focus on understanding the current view of the role of epigenomic reprogramming in gout and the mechanistic pathways of action.

Phillyrin inhibits oxidative stress and neutrophil extracellular trap formation through the KEAP1/NRF2 pathway in gouty arthritis.

Gouty arthritis (GA) is an inflammatory disorder characterized by deposition of monosodium urate (MSU) crystal in joints. Phillyrin, a natural compound with anti-inflammatory properties, shows promise in mitigating inflammatory responses. This study investigates the therapeutic potential of phillyrin in GA and explores its mechanisms of action. GA was induced in mice via intraarticular MSU injection, and joint inflammation, inflammatory cell infiltration, and their level in serum/tissue were assessed. Key proteins in the NF-κB and NLRP3 pathways were examined using western blot analysis. The impact of phillyrin on oxidative stress, neutrophil extracellular trap (NET) formation, and neutrophil accumulation was evaluated by measuring CD11b + Ly6G + cells, MPO, CitH3, extracellular DNA ratio, and oxidative stress markers. In vitro studies assessed the effects of phillyrin on oxidative stress, cell viability, cytokine production, and NET formation in MSU-treated neutrophils. The KEAP1/NRF2 pathway's role was analyzed using ML385, an NRF2 inhibitor. Phillyrin significantly reversed MSU-induced ankle swelling and inflammatory cell infiltration in joint tissues. It suppressed pro-inflammatory cytokines and proteins in the NF-κB and NLRP3 pathways. Phillyrin reduced neutrophil infiltration, evidenced by lower MPO activity and NET formation, marked by reduced CitH3 expression. In vitro, phillyrin inhibited inflammatory marker expression and NET formation without affecting cell viability. It also restored antioxidant enzyme levels and reduced ROS production, regulating the KEAP1/NRF2 pathway, enhancing NRF2 expression and stability. These effects were reversed by NRF2 inhibition with ML385. Phillyrin alleviates GA by reducing joint inflammation, inhibiting NET formation, and suppressing oxidative stress through NRF2 modulation.

Systemic Inflammation In Asymptomatic Hyperuricemia With Sonographic Crystal Deposits, Including A Comparison With Normouricemia And Gout.

To describe the inflammatory profile of asymptomatic hyperuricemia (AH) with ultrasound evidence of monosodium urate (MSU) crystals (AH-MSUpos), vs AH without deposits (AH-MSUneg), intercritical gout, and normouricemia. Based on serum urate levels, musculoskeletal ultrasound, and history of flares, we divided 122 participants into four groups: normouricemia, AH-MSUneg, AH-MSUpos, and intercritical gout. We tested four ultrasound definitions for MSU deposition in AH: grade 2-3 (G2-3) double contour and/or tophi, G1-3 double contour and/or tophi, G1-3 Stewart scheme (double contour sign in knee cartilage and/or first metatarsophalangeal joint and/or tophi in first metatarsophalangeal joint), and G2-3 Stewart scheme. Serum acute phase reactants, cytokines, pyroptosis derivates, and neutrophil-related proteins were measured and compared between groups. A linear regression model was fitted to correlate crystal and inflammatory burden (measured by ultrasound) with inflammatory markers in hyperuricemics. Rates of MSU deposition in AH ranged from 26.0% to 68.8%, depending on the definition used. Levels of CRP, leukocytes, IL-1RA, IL-6, sIL-6R, IL-18, TNF-α, TGF-β, and galectin-3 were higher in hyperuricemics vs normouricemics. Sex, obesity, and comorbidity scores influenced some comparisons. We saw no differences comparing AH-MSUpos vs AH-MSUneg groups, except for higher calprotectin using G1-3 sonographic definitions and higher CRP and TGF-β when restricted to women and obese participants. Hyperuricemia is associated with substantial inflammation and some degree of active pyroptosis. Four different ultrasound definitions for AH with MSU deposits yielded similar findings, although we noted some differences in calprotectin, CRP, and TGF-β. Sex, obesity, and comorbidities influenced some inflammatory responses.

Activation of osmo-sensitive LRRC8 anion channels in macrophages is important for micro-crystallin joint inflammation

Deposition of monosodium urate and calcium pyrophosphate (MSU and CPP) micro-crystals is responsible for painful and recurrent inflammation flares in gout and chondrocalcinosis. In these pathologies, the inflammatory reactions are due to the activation of macrophages responsible for releasing various cytokines including IL-1β. The maturation of IL-1β is mediated by the multiprotein NLRP3 inflammasome. Here, we find that activation of the NLRP3 inflammasome by crystals and concomitant production of IL-1β depend on cell volume regulation via activation of the osmo-sensitive LRRC8 anion channels. Both pharmacological inhibition and genetic silencing of LRRC8 abolish NLRP3 inflammasome activation by crystals in vitro and in mouse models of crystal-induced inflammation. Activation of LRRC8 upon MSU/CPP crystal exposure induces ATP release, P2Y receptor activation and intracellular calcium increase necessary for NLRP3 inflammasome activation and IL-1β maturation. We identify a function of the LRRC8 osmo-sensitive anion channels with pathophysiological relevance in the context of joint crystal-induced inflammation.

Mechanism of Biqi capsules in the treatment of gout based on network pharmacology and experimental verification

Ethnopharmacological relevanceGout is a crystal-related arthropathy caused by monosodium urate (MSU) deposition, resulting from purine metabolism disorders and hyperuricemia (HUA). Gout belongs to the traditional medicine category of Bi syndrome. Biqi capsules (BQ) is a traditional Chinese medicine formula used to treat Bi syndrome. The BQ prescription is derived from the ancient prescription of Hua Tuo, a famous physician in the Han Dynasty. Aim of the studyTo study the effect and mechanism of BQ in treating acute gouty arthritis (AGA) and HUA. Materials and methodsAnalyzing BQ's signaling pathways for gout treatment via network pharmacology. The HUA model was induced orally with adenine and potassium oxonate. The rat AGA model was established by MSU injection. In vitro, MH7A and RAW 246.7 cells were treated with LPS and MSU. Serum uric acid, creatinine, and urea nitrogen levels were evaluated. Kidney and ankle joint pathology was observed via HE staining. Inflammatory signaling pathway proteins, epithelial-mesenchymal transition (EMT) pathway proteins, and uric acid metabolism-related proteins were detected by Western blot. Results1780 potential targets for gout treatment were identified, and 1039 target proteins corresponding to BQ's active ingredients were obtained. Pathway enrichment analysis revealed BQ improved gout mainly through inflammatory pathways. Experimental results showed BQ could reduce serum uric acid level and increase uric acid clearance rate by regulating the expression of adenosine deaminase (ADA), and organic anion transporter 1 (OAT1) and glucose transporter 9 (GLUT9) in HUA mice. BQ could improve renal function and injury by inhibiting the NLRP3 pathway in HUA mice' kidneys. Additionally, BQ could alleviate ankle joint swelling and synovial injury, inhibit the TLR4/NLRP3 pathway, and reduce levels of inflammatory factors including interleukin 6 (IL-6), interleukin 1β (IL-1β), and tumor necrosis factor-alpha (TNF-α) in AGA rats. The main component of BQ, brucine, could inhibit the activation of NLRP3/NF-κB pathway induced by MSU and reduce the expression level of inflammatory factors (IL-6, IL-1β, and TNF-α) in macrophages. Brucine could inhibit the activation of the EMT pathway and reduce the expression level of inflammatory factors (IL-6, TNF-α) in human fibroblast-like synoviocytes (MH7A cells) induced by MSU. ConclusionsBQ effectively reduced serum uric acid levels, improved kidney and joint damage, and ameliorated the inflammatory response caused by MSU. Its main component, brucine, effectively improved the inflammatory response and reduced the invasive ability of synoviocytes induced by MSU.

The pathogenesis of gout: molecular insights from genetic, epigenomic and transcriptomic studies.

The pathogenesis of gout involves a series of steps beginning with hyperuricaemia, followed by the deposition ofmonosodium urate crystal in articular structures and culminating in an innate immune response, mediated by the NLRP3 inflammasome, to the deposited crystals. Large genome-wide association studies (GWAS) of serum urate levels initially identified the genetic variants with thestrongest effects, mapping mainlyto genes that encode urate transporters in the kidney and gut. Other GWAS highlighted the importance of uncommon genetic variants. More recently, genetic and epigenetic genome-wide studies have revealed new pathways in the inflammatory process of gout, including genetic associations with epigenomic modifiers. Epigenome-wide association studies are also implicating epigenomic remodelling in gout, which perhaps regulates the responsiveness of the innate immune system to monosodium urate crystals. Notably, genes implicated in gout GWAS do not include those encodingcomponents of the NLRP3 inflammasome itself, but instead include genes encoding moleculesinvolved in its regulation. Knowledge of the molecular mechanisms underlying gout has advanced through the translation of genetic associations into specific molecular mechanisms. Notable examples include ABCG2, HNF4A, PDZK1, MAF and IL37. Current genetic studies are dominated by participants of European ancestry; however, studies focusing on other population groups are discovering informative population-specific variants associated with 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.

A Conceptual Study on Vatarakta w.s.r. to Gouty Arthritis

The wellbeing of an individual depends on his/her diet and lifestyle. The rapid development and modernisation in India are causing serious health problems and Vatarakta is one of them. Vatarakta, is described under Vatavyadhis by different Acharya’s. The vitiated Vata and Rakta causes this disease, hence called Vatarakta. Gout is an inflammatory disease caused by deposition of Mono-Sodium Urate (MSU) crystals in and around synovial joints. Recent reports of prevalence and incidence of gout vary widely but ranges from prevalence of 1-2%, with greater than 5:1 male preponderance. It is imperative to comprehend complexities of Vatarakta in order to accurately diagnose and treat it, considering its increasing occurrence worldwide and the substantial influence, it has affected individuals’ quality of life. Methods: After a thorough literary review, focusing on classical Ayurvedic texts, alongside recent research articles and reviews. The gathered information was analysed to present cohesive narrative on the Niadana, Samprapti and Chikitsa of Vatarakta. Results: Vatarakta is a result of aggravated Vata Dosha and impaired Rakta Dhatu, leading to severe pain, inflammation, and joints deformity. The disease progression is influenced by dietary habits, lifestyle factors, and genetic predisposition. Its treatment involves a multi-factorial approach, including Shodhana, Shamana, dietary regulations, and lifestyle modification. Conclusion: The Ayurvedic perspective on Vatarakta offers a holistic approach in understanding and managing the disease, emphasizing the balance of bodily Doshas, detoxification, and rejuvenation. Integrating Ayurvedic principles with modern medical practices may provide a comprehensive treatment for Vatarakta.

Perfect Timing for Canakinumab Use in Gout

Gout is an inflammatory disease caused by the deposition of monosodium urate (MSU) crystals. Recently, the American College of Rheumatology (ACR) has recommended the usage of interleukin (IL)-1 inhibitor in gout patients who are refractory to typical anti-inflammatory drugs. An example of IL-1 inhibitor is canakinumab. Not much is known regarding the usage of canakinumab in gout arthritis. Thus, we decided to conduct a narrative review that summarizes the efficacy and safety of canakinumab in gout patients. In this review, we found that canakinumab is superior to non-steroidal anti-inflammatory drugs (NSAIDs) and corticosteroids in treating acute gout flares. In addition, canakinumab may also be considered as a preventive therapy for gout flares in patients receiving urate-lowering therapy. Overall, canakinumab has mild side effects but may occasionally cause serious infections. Canakinumab is also generally safe for use during pregnancy. Due to the lack of studies, the safety of canakinumab in lactating women, geriatric patients, and patients with hepatic or renal impairment is still unknown.

DUSP1 Mitigates MSU-Induced Immune Response in Gouty Arthritis Reinforcing Autophagy.

Persistent hyperuricemia can lead to the generation and deposition of monosodium urate (MSU) crystals. This can trigger gouty arthritis (GA), which in turn induces inflammation. Activation of the Nod-like receptor pyrin domain containing 3 (NLRP3) inflammasome plays a critical role in the onset and progression of GA. Autophagy may have a dual effect on GA with regard to the NLRP3 inflammasome. Therefore, the present study aimed to gain a deeper comprehension of the interaction between autophagy and NLRP3 inflammasome activation is imperative for developing more efficacious treatments for GA. Peripheral blood monocytes (PBMCs) were first isolated from GA patients and healthy controls and underwent bulk RNA sequencing analysis. Overexpression and knockdown of dual specificity phosphatase 1 (DUSP1) was performed in THP-1 monocytes to investigate its role in the immune response and mitochondrial damage. The luciferase assay and Western blot analysis were used to study the interaction between autophagy and NLRP3 inflammasome activation. Bulk RNA sequencing analysis showed significant upregulation of DUSP1 expression in PBMCs from GA patients compared to healthy controls. This result was subsequently verified by reverse transcription quantitative polymerase chain reaction (RT-qPCR). DUSP1 expression in human THP-1 monocytes was also shown to increase after MSU treatment. Downregulation of DUSP1 expression increased the secretion of inflammatory cytokines after MSU treatment, whereas the overexpression of DUSP1 decreased the secretion levels. Lipopolysaccharides (LPS) combined with adenosine-triphosphate (ATP) led to mitochondrial damage, which was rescued by overexpressing DUSP1. DUSP1 overexpression further increased the level of autophagy following MSU treatment, whereas downregulation of DUSP1 decreased autophagy. Treatment with the autophagy inhibitor 3-Methyladenine (3-MA) restored inflammatory cytokine secretion levels in the DUSP1 overexpression group. MSU caused pronounced pathological ankle swelling in vivo. However, DUSP1 overexpression significantly mitigated this phenotype, accompanied by significant downregulation of inflammatory cytokine secretion levels in the joint tissues. This study revealed a novel function and mechanism for DUSP1 in promoting autophagy to mitigate the MSU-induced immune response in GA. This finding suggests potential diagnostic biomarkers and anti-inflammatory targets for more effective GA therapy.

Mechanism of neutrophil extracellular traps in the pathogenesis of gout.

Gout is a self-limited inflammatory disease caused by the deposition of monosodium urate (MSU) crystals in joints and surrounding tissues due to abnormal purine metabolism. Neutrophil extracellular traps (NETs) are formed by neutrophils in response to pathogen attack. During gout, NETs induced by MSU crystals exacerbate inflammation, and aggregated NETs (aggNETs) promote the resolution of gout-associated inflammation by encapsulating MSU crystals, degrading cytokines and chemokines, and blocking the recruitment and activation of neutrophils. With disease progression, NETs participate in the formation of tophi. Therefore, aggNETs are a possible mechanism of spontaneous gout regression. Studying the specific mechanism by which NETs affect inflammatory bursts and spontaneous regression in gout patients is important. This review summarises the role of NETs in different stages of gout and the specific pathogenesis of NETs in gout to provide new ideas for the diagnosis and treatment of gout.

Gout, hyperuricemia and NLRP3 inflammasome: a literature review

Gout is a form of self-limiting inflammatory arthritis caused by hyperuricemia and the deposition of monosodium urate (MSU) crystals in joint tissues. This deposition causes the activation of the NLRP3 inflammasome, thus triggering an inflammatory cascade. Intense activation of the NLRP3 inflammasome is associated with the pathogenesis of several inflammatory diseases, including gout. For this reason, this inflammasome has become a potential target for controlling this type of inflammation. In this review, 33 publications were selected from the Google Scholar, Scielo and PubMed platforms, thus providing a comprehensive perspective on the condition of gout and its relationship with the NLRP3 inflammasome. This review provides a broad view of the inflammatory process associated with gout, focusing on the NLRP3 inflammasome. In this context, interventions targeting these inflammasome and IL-1 pathways appear promising for the treatment of this disease.

Major cardiovascular events in patients with cardiovascular monosodium urate deposits in atherosclerotic plaques.

To determine the association of cardiovascular atherosclerotic plaque monosodium urate deposits with the occurrence of major cardiovascular events in gout and hyperuricemia patients. This retrospective cohort study included patients with clinically suspicion of gout, who performed a dual energy computed tomography of the affected limb and thorax between June 1st, 2012 and December 5th, 2019. Clinical and laboratory parameters were retrieved from patientś charts. Established cardiovascular risk factors were evaluated. Medical history review identified the presence of major adverse cardiac events with a median follow up time of 33 months (range 0-108 months) after the performed computed tomography scan. Full data sets were available for 189 patients: 131 (69.3%) gout patients, 40 (21.2%) hyperuricemia patients, and 18 (9.5%) controls. Patients with cardiovascular monosodium urate deposits (n = 85/189, 45%) revealed increased serum acute phase reactants, uric acid levels and calcium scores in computed tomography compared with patients without cardiovascular monosodium urate deposits. Major adverse cardiac events were observed in 35 patients (18.5%) with a higher prevalence in those patients revealing cardiovascular monosodium urate deposits (n = 22/85, 25.9%) compared with those without cardiovascular monosodium urate deposits (n = 13/104, 12.5%, OR 2.4, p= 0.018). This is the first study demonstrating the higher hazard of major adverse cardiac events in patients with dual energy computed tomography-verified cardiovascular monosodium urate deposits. The higher prevalence of cardiac events in patients with cardiovascular monosodium urate deposits may facilitate risk stratification of gout patients, as classical cardiovascular risk scores or laboratory markers fail in their proper identification.

CD8 T cell-derived perforin regulates macrophage-mediated inflammation in a murine model of gout.

Gout is characterized by hyperuricemia and recurrent inflammatory episodes caused by intra-articular crystal deposition of monosodium urate (MSU). There is a clear relationship between gout and metabolic syndrome. Recent evidence indicates that perforin plays a role in regulating glucose homeostasis and provides protection in diet-induced non-alcoholic steatohepatitis models. However, the impact of perforin on immune inflammation in gout remains unclear. We induced acute gout models in both wild-type (WT) mice and Prf1null mice by administering intra-articular injections of MSU crystals. We compared the ankle joint swelling and the histological score between the two groups. Furthermore, we investigated underlying mechanisms through in vitro co-culture experiments involving CD8 T cells and macrophages. In this study, Prf1null mice showed significantly more pronounced ankle swelling with increased inflammatory cell infiltrations compared with WT mice 24h after local MSU injection. Moreover, MSU-induced Prf1null mice exhibited increased accumulation of CD8 T cells but not NK cells. Perforin-deficient CD8 T cells displayed reduced cytotoxicity towards bone marrow-derived M0 and M1 macrophages and promoted TNF-α secretion from macrophage. Perforin from CD8 T cells limits joint inflammation in mice with acute gout by downregulating macrophage-mediated inflammation. Key Points • Perforin deficiency increased swelling in the ankle joints of mice upon MSU injection. • Perforin deficiency is associated with increased immune cell recruitment and severe joint damage in gout. • Perforin regulated CD8 T cell accumulation in gout and promoted CD8 T cell cytotoxicity towards M0 and M1 macrophages. • CD8 T cell-derived perforin regulated pro-inflammatory cytokine secretion of macrophage.

Spatiotemporal Observation of Monosodium Urate Crystals Deposition in Synovial Organoids Using Label-Free Stimulated Raman Scattering.

Gout, a common form of arthritis, is characterized by the deposition of monosodium urate (MSU) crystals in joints. MSU deposition in synovial tissues would initiate arthritis flares and recurrence, causing irreversible joint damage. However, the dynamic deposition of MSU crystals in tissues lacks experimental observation. In this study, we used chemical-specific, label-free stimulated Raman scattering (SRS) microscopy to investigate the spatiotemporal deposition and morphological characteristics of MSU crystals in human synovial organoids. Our findings revealed a critical 12-h window for MSU deposition in the lining layer of gouty synovium. Moreover, distinctive inflammatory reactions of the lining and sublining synovial layers in gout using SRS microscopy were further verified by immunofluorescence. Importantly, we identified a crucial proinflammatory role of sublining fibroblast-like synoviocytes, indicating a need for targeted medication treatment on these cells. Our work contributes to the fundamental understanding of MSU-based diseases and offers valuable insights for the future development of targeted gout therapies.

Optimising the Use of Ultrasound in Gout: A Review from the Ground Up

The use of ultrasonography (US) has considerable potential for the diagnosis and monitoring of gout due to its capacity to detect monosodium urate deposits. In the last decade, a critical amount of scientific data has become available. Consensus-based definitions for ultrasonographic elementary lesions in gout have been developed, tested, and validated, as well as a semiquantitative scoring system for their quantification. Many scanning protocols have been proposed in different clinical scenarios. In this review, we formulate a set of practical suggestions for the use of the US in daily practice. We discuss the current knowledge to indicate which joints and structures are to be scanned and which elementary findings are to be evaluated according to the clinical scenario. While for some clinical settings, a quite definite scanning protocol can be indicated, others still need to be further investigated, and how to obtain the best out of the US is still entrusted to the individual experience.

Frequently Encountered Artifacts in the Application of Dual-Energy Computed Tomography to Cardiovascular Imaging for Urate Crystals in Gout: A Matched-Control Study.

There is surging interest in using dual-energy computed tomography (DECT) to identify cardiovascular monosodium urate (MSU) deposits in patients with gout. We sought to examine the prevalence and characterization of cardiovascular DECT artifacts using non-electrocardiogram (EKG)-gated DECT pulmonary angiograms. We retrospectively reviewed non-EKG-gated DECT pulmonary angiograms performed on patients with and without gout at a single academic center. We noted the presence and locations of vascular green colorization using the default postprocessing two-material decomposition algorithm for MSU. The high- and low-energy grayscale images and advanced DECT measurements were used to determine whether they were true findings or artifacts. We classified artifacts into five categories: streak, contrast medium mixing, misregistration due to motion, foreign body, and noise. Our study included CT scans from 48 patients with gout and 48 age- and sex-matched controls. The majority of patients were male with a mean age of 67 years. Two independent observers attributed all areas of vascular green colorization to artifacts. The most common types of artifacts were streak (56% vs 57% between patients and controls, respectively) and contrast medium mixing (51% vs 65%, respectively). Whereas some of the default DECT measurements of cardiovascular green colorization were consistent with values reported for subcutaneous tophi, advanced DECT measurements were not consistent with that of tophi. Artifacts that could be misconstrued as cardiovascular MSU deposits were commonly identified in patients with and without gout on non-EKG-gated DECT pulmonary angiograms. These artifacts can inform future vascular DECT studies on patients with gout to minimize false-positive findings.

Targeting Neutrophil Extracellular Traps in Gouty Arthritis: Insights into Pathogenesis and Therapeutic Potential.

Gouty arthritis (GA) is an immune-mediated disorder characterized by severe inflammation due to the deposition of monosodium urate (MSU) crystals in the joints. The pathophysiological mechanisms of GA are not yet fully understood, and therefore, the identification of effective therapeutic targets is of paramount importance. Neutrophil extracellular traps (NETs), an intricate structure of DNA scaffold, encompassing myeloperoxidase, histones, and elastases - have gained significant attention as a prospective therapeutic target for gouty arthritis, due to their innate antimicrobial and immunomodulatory properties. Hence, exploring the therapeutic potential of NETs in gouty arthritis remains an enticing avenue for further investigation. During the process of gouty arthritis, the formation of NETs triggers the release of inflammatory cytokines, thereby contributing to the inflammatory response, while MSU crystals and cytokines are sequestered and degraded by the aggregation of NETs. Here, we provide a concise summary of the inflammatory processes underlying the initiation and resolution of gouty arthritis mediated by NETs. Furthermore, this review presents an overview of the current pharmacological approaches for treating gouty arthritis and summarizes the potential of natural and synthetic product-based inhibitors that target NET formation as novel therapeutic options, alongside elucidating the intrinsic challenges of these inhibitors in NETs research. Lastly, the limitations of HL-60 cell as a suitable substitute of neutrophils in NETs research are summarized and discussed. Series of recommendations are provided, strategically oriented towards guiding future investigations to effectively address these concerns. These findings will contribute to an enhanced comprehension of the interplay between NETs and GA, facilitating the proposition of innovative therapeutic strategies and novel approaches for the management of GA.

Development of a deep learning model for the automated detection of green pixels indicative of gout on dual energy CT scan

BackgroundDual-energy CT (DECT) is a non-invasive way to determine the presence of monosodium urate (MSU) crystals in the workup of gout. Color-coding distinguishes MSU from calcium following material decomposition and post-processing. Most software labels MSU as green and calcium as blue. There are limitations in the current image processing methods of segmenting green-encoded pixels. Additionally, identifying green foci is tedious, and automated detection would improve workflow. This study aimed to determine the optimal deep learning (DL) algorithm for segmenting green-encoded pixels of MSU crystals on DECTs. MethodsDECT images of positive and negative gout cases were retrospectively collected. The dataset was split into train (N = 28) and held-out test (N = 30) sets. To perform cross-validation, the train set was split into seven folds. The images were presented to two musculoskeletal radiologists, who independently identified green-encoded voxels. Two 3D Unet-based DL models, Segresnet and SwinUNETR, were trained, and the Dice similarity coefficient (DSC), sensitivity, and specificity were reported as the segmentation metrics. ResultsSegresnet showed superior performance, achieving a DSC of 0.9999 for the background pixels, 0.7868 for the green pixels, and an average DSC of 0.8934 for both types of pixels, respectively. According to the post-processed results, the Segresnet reached voxel-level sensitivity and specificity of 98.72 % and 99.98 %, respectively. ConclusionIn this study, we compared two DL-based segmentation approaches for detecting MSU deposits in a DECT dataset. The Segresnet resulted in superior performance metrics. The developed algorithm provides a potential fast, consistent, highly sensitive and specific computer-aided diagnosis tool. Ultimately, such an algorithm could be used by radiologists to streamline DECT workflow and improve accuracy in the detection of gout.