Diagnosing and Treating Gout: A Review to Aid Primary Care Physicians

Benzbromarone Analog SAR: Potent hURAT1 (SLC22A12) Inhibitors and Drug Transporter Interaction Studies

Purpose

There were two main purposes for this study. One, to report two benzbromarone analogs and test their in vitro activity in the URAT1 inhibition assay; and two, to probe the structure-activity relationship (SAR) of various benzbromarone analogs regarding other drug transporters that may play a role in the uric acid uptake/elimination interplay.

Methods

In brief, chemical synthesis of two benzbromarone analogs was prepared using methods analogous to those reported. Furthermore, drug transporter protein inhibition was investigated in vitro using oocytes expressing hURAT1, hURATv1 (GLUT9), hOAT1, hOAT3, hOAT10, hNPT4, OATP1B1, OATP1B3 and OATP2B1 prepared and utilized to conduct inhibition studies. In addition, one novel benzbromarone analog was studied via in vivo rat pharmacokinetic experiments to determine apparent oral bioavailability.

Results

Two analogs, 6-fluoro-benzbromarone (5) and 5,6-difluoro-benzbromarone (9), were synthetically prepared and 5 had a hURAT1 IC50 inhibition of 18 ± 4 nM, while analog (9) had an IC50 of 245 ± 64 nM. Analog (5) had good oral bioavailability (Fa) >0.6 in rat. Eadie-Hofstee plot and double-reciprocal plot of the Michaelis-Menten equation are summarized for benzbromarone (2) and its major Phase I metabolite 6-hydroxy-benzbromarone (3).

Conclusion

These results illustrate that the Km for [14C]UA uptake was not altered in the presence of 2 or 3, but rather the Vmax was reduced in the presence of inhibitors when added to the uptake solutions. As a result, these data support the notion that 2 and 3 inhibit [14C]UA uptake by non-competitive inhibition and not at the URAT1 binding site.

Interleukin-1β inhibitors for the management of acute gout flares: a systematic literature review

OBJECTIVES

The objective of this systematic review was to assess the effects of interleukin-1β (IL-1β) inhibitors on gout flares.

METHODS

Studies published between 2011 and 2022 that evaluated the effects of IL-1β inhibitors in adult patients experiencing gout flares were eligible for inclusion. Outcomes including pain, frequency and intensity of gout flares, inflammation, and safety were assessed. Five electronic databases (Pubmed/Medline, Embase, Biosis/Ovid, Web of Science and Cochrane Library) were searched. Two independent reviewers performed study screening, data extraction and risk of bias assessments (Cochrane Risk of Bias Tool 2 for randomised controlled trials [RCTs] and Downs and Black for non-RCTs). Data are reported as a narrative synthesis.

RESULTS

Fourteen studies (10 RCTs) met the inclusion criteria, with canakinumab, anakinra, and rilonacept being the three included IL-1β inhibitors. A total of 4367 patients with a history of gout were included from the 14 studies (N = 3446, RCTs; N = 159, retrospective studies [with a history of gout]; N = 762, post hoc analysis [with a history of gout]). In the RCTs, canakinumab and rilonacept were reported to have a better response compared to an active comparator for resolving pain, while anakinra appeared to be not inferior to an active comparator for resolving pain. Furthermore, canakinumab and rilonacept reduced the frequency of gout flares compared to the comparators. All three medications were mostly well-tolerated compared to their comparators.

CONCLUSION

IL-1β inhibitors may be a beneficial and safe medication for patients experiencing gout flares for whom current standard therapies are unsuitable.

REVIEW PROTOCOL REGISTRATION

PROSPERO ID: CRD42021267670.

Potential of Leave and Fruit Ethanolic Extract of Etlingera hemisphaerica as Antihyperuricemic in Mice (Mus musculus)

<b>Background and Objective:</b> Hyperuricemia is a disease triggered by disorders of uric acid metabolism. Therefore, this study evaluated the potential of leaves ethanolic extract of <i>Etlingera hemisphaerica</i> (LE3H) and fruits ethanolic extract <i>E. hemisphaerica</i> (FE3H) to restore hyperuricemia in mice. <b>Materials and Methods:</b> Six groups (A0, A1, A2, A3, A4 and A5) each consisted of four male mice. Hyperuricemia in mice was induced by giving 0.3 mL of fresh chicken liver juice (FCLJ) for seven days (A1, A2, A3, A4 and A5). The condition of hyperuricemia in A1 is not neutralized. Meanwhile, hyperuricemia conditions in A2, A3, A4 and A5 were neutralized for seven days by giving 0.01 mg g<sup></sup><sup>1</sup> body weight (BW) allopurinol, 0.13, 0.26 and 0.36 mg g<sup></sup><sup>1</sup> BW LE3H. The control group (A0) only received double-distilled water in the same way. Blood uric acid levels were measured with the GCU Meter Device before and after the induction of hyperuricemia and after efforts to neutralize the hyperuricemia condition. Six groups (B0, B1, B2, B3, B4, B5) each consisting of four male mice were also provided to test the potential of FE3H. The recovery potential FE3H against hyperuricemia was tested separately in the same way as was done for LE3H. <b>Results:</b> Giving FCLJ significantly increased (140.00-187.00%) uric acid compared to the control, so hyperuricemia was achieved. Doses of 0.13, 0.26 and 0.36 mg g<sup></sup><sup>1</sup> BW LE3H significantly recovered hyperuricemia as much as 54.09, 56.14 and 60.88%, respectively. Meanwhile, doses of 0.13, 0.26 and 0.36 mg g<sup></sup><sup>1</sup> FE3H significantly recovered hyperuricemia as much as 60.37, 62.24 and 65.572%, respectively. The LE3H and FE3H at the same dose showed that FE3H had a higher potential to restore hyperuricemia than LE3H. <b>Conclusion:</b> Leave and fruit ethanolic extract of <i>E. hemisphaerica</i> can potentially restore hyperuricemia in mice.

Crosstalk between xanthine oxidase (XO) inhibiting and cancer chemotherapeutic properties of comestible flavonoids- a comprehensive update

Gout is an inflammatory disease caused by metabolic disorder or genetic inheritance. People throughout the world are strongly dependent on ethnomedicine for the treatment of gout and some receive satisfactory curative treatment. The natural remedies as well as established drugs derived from natural sources or synthetically made exert their action by mechanisms that are closely associated with anticancer treatment mechanisms regarding inhibition of xanthine oxidase, feedback inhibition of de novo purine synthesis, depolymerization and disappearance of microtubule, inhibition of NF-ĸB activation, induction of TRAIL, promotion of apoptosis, and caspase activation and proteasome inhibition. Some anti-gout and anticancer novel compounds interact with same receptors for their action, e.g., colchicine and colchicine analogues. Dietary flavonoids, i.e., chrysin, kaempferol, quercetin, fisetin, pelargonidin, apigenin, luteolin, myricetin, isorhamnetin, phloretinetc etc. have comparable IC₅₀ values with established anti-gout drug and effective against both cancer and gout. Moreover, a noticeable number of newer anticancer compounds have already been isolated from plants that have been using by local traditional healers and herbal practitioners to treat gout. Therefore, the anti-gout plants might have greater potentiality to become selective candidates for screening of newer anticancer leads.

Comparative transcriptomic analysis of the l-4i silkworm (Lepidoptera: Bombyx mori) mutants and its wild-type strain P33 by RNA-Seq

The silkworm (Bombyx mori) is a domesticated holometabolous insect, and more than 400 Mendelian mutations have been identified. Investigating the mechanism behind these silkworm mutants is essential for understanding the development of silkworms and other lepidopterans, and lethal genes could be used for pest control. The lethal silkworm mutant in the fourth instar (l-4i) has been recently found; however, the underlying mechanism is not yet clear. Herein, we studied the l-4i mutant and its wild-type strain P33 using RNA sequencing (RNA-seq). Our results revealed that 2013 genes were significantly downregulated, and 20 biological processes, including spliceosomal snRNP assembly, protein folding and protein catabolic process, were significantly enriched in these downregulated genes. Moreover, 2405 genes were significantly upregulated in the l-4i mutant, and 20 biological processes, including purine nucleobase metabolic process, nucleoside metabolic process and de novo IMP biosynthetic process, were significantly enriched in these upregulated genes. The study suggests that the imbalance of multiple biological processes and pathways and abnormal protein generation from RNA alternative splicing may cause the death of the l-4i mutant.

Comparative Study of Anti-Gouty Arthritis Effects of Sam-Myo-Whan according to Extraction Solvents

Sam-Myo-Whan (SMW) has been used in Korean and Chinese traditional medicine to help treat gout, by reducing swelling and inflammation and relieving pain. This study compared the effects of SMW extracted by using different solvents, water (SMWW) and 30% EtOH (SMWE), in the treatment of gouty arthritis. To this end, we analyzed the main components of SMWW and SMWE, using high-performance liquid chromatography (HPLC). Anti-hyperuricemic activity was evaluated by measuring serum uric acid levels in hyperuricemic rats. The effects of SMWW and SMWE on swelling, pain, and inflammation in gouty arthritis were investigated by measuring affected limb swelling and weight-bearing, as well as by enzyme-linked immunosorbent assays, to assess the levels of proinflammatory cytokines and myeloperoxidase (MPO). In potassium oxonate (PO)-induced hyperuricemic rats, SMWW and SMWE both significantly decreased serum uric acid to similar levels. In monosodium urate (MSU)-induced gouty arthritis mice, SMWE more efficiently decreased paw swelling and attenuated joint pain compare to SMWW. Moreover, SMWE and SMWW suppressed the level of inflammation by downregulating proinflammatory cytokines (interleukin-1β, tumor necrosis factor-α, and interleukin-6) and MPO activity. HPLC analysis further revealed that berberine represented one of the major active ingredients demonstrating the greatest change in concentration between SMWW and SMWE. Our data demonstrate that SMWE retains a more effective therapeutic concentration compared to SMWW, in a mouse model of gouty arthritis.

Metabolomic profiling of goslings with visceral gout reveals a distinct metabolic signature

1.The objective of the experiment was to analyse serum profiles of goslings with visceral gout and compare them with those of healthy individuals to identify differentially-abundant metabolites as potential biomarkers. 2.Untargeted gas chromatography and time-of-flight mass spectrometry (GC-TOF-MS) metabolomic profiling was used to compare the serum metabolome of 15 goslings (Anser cygnoides) with gout and 15 healthy goslings (control). 3.Goslings with gout had a metabolic profile distinct from that of the controls, with 45 metabolite levels differing significantly (VIP > 1; P < 0.05) between both groups. Nine metabolites (hydrocortisone, glucose, trans-4-hydroxy-L-proline, galactose, 2-deoxy-D-galactose, beta-mannosylglycerate, d-glucoheptose, zymosterol, and hypoxanthine) were selected through receiver operating characteristics (ROC) analysis (area under curve (AUC) score ≥0.85) as potential biomarkers. Pathway analysis revealed that metabolites with differing levels were mainly involved in galactose, arginine and proline and purine metabolisms. 4.These results provided new insights into the pathogenesis of gout. Increased xanthine and hypoxanthine with decreased hydrocortisone provide promising biomarkers for gosling gout diagnosis. The findings suggested that hepatic metabolic disorders frequently occur in the development of avian gout.

Study on the diagnosis of gout with xanthine and hypoxanthine

BACKGROUND

Hyperuricemia is the only biochemical index in the classification of acute gouty arthritis in American Rheumatism Association 1977 and the main basis of clinical diagnosis for most doctors. However, nearly half of the time gout occurs without hyperuricemia, especially in an acute attack，which leads to an urgent need to find a new substitute diadynamic criteria of gout. Xanthine and hypoxanthine, as precursors of uric acid, have been reported to be high in gout patients with hyperuricemia and presumed to be gout biomarkers.

OBJECTIVES

To further explore the possibility of xanthine and hypoxanthine to be gout biomarkers as substitutes for uric acid.

METHODS

A reversed-phase HPLC-UV method was employed for simultaneous quantitative detection of uric acid (UA), xanthine (X), and hypoxanthine (HX) in gout patients' (with and without hyperuricemia) and healthy persons' serum.

RESULTS

The xanthine and hypoxanthine concentrations in gout patients with hyperuricemia and without hyperuricemia are higher than in healthy persons with a P < 0.001.

CONCLUSIONS

This study supplements previous researches by confirming that xanthine and hypoxanthine are significantly elevated in gout patients' serum especially in patients' with normouricemia, which supported xanthine and hypoxanthine may have clinical application for the diagnosis of gout.

Anti-inflammatory effects of traditional mixed extract of medicinal herbs (MEMH) on monosodium urate crystal-induced gouty arthritis

Korean oriental medicine prescription is widely used for the treatment of gouty diseases. In the present study, we investigated anti-inflammatory effects of modified Korean herbal formulation, mixed extract of medicinal herbs (MEMH), and its modulatory effects on inflammatory mediators associated with gouty arthritis. Both in vitro and in vivo studies were carried out to assess the anti-inflammatory efficacy of MEMH on monosodium urate (MSU) crystals-induced gouty inflammation. MSU crystals stimulated human chondrosarcoma cell line, SW1353, and human primary chondrocytes were treated with MEMH in vitro. The expression levels of pro-inflammatory mediators and metalloproteases were analyzed. The effect of MEMH on NFκB signaling pathway in SW1353 cells was examined. Effect of MEMH on the mRNA expression level of pro-inflammatory mediators and chemotactic factor from human monocytic cell line, THP-1, was also analyzed. The probable role of MEMH in the differentiation process of osteoblast like cells, SaOS-2, after MSU treatment was also observed. To investigate the effects of MEMH in vivo, MSU crystals-induced ankle arthritic model was established. Histopathological changes in affected joints and plasma levels of pro-inflammatory mediators (IL-1β and TNFα) were recorded. MEMH inhibited NFκB signaling pathway and COX-2 protein expression in chondrocytes. MSU-induced mRNA expressions of pro-inflammatory mediators and chemotactic cytokines were suppressed by MEMH. In MSU crystals-induced ankle arthritic mouse model, administration of MEMH relieved inflammatory symptoms and decreased the plasma levels of IL-1β and TNFα. The results indicated that MEMH can effectively inhibit the expression of inflammatory mediators in gouty arthritis, demonstrating its potential for treating gouty arthritis.

Treatment of gout combined with Kienböck's disease: A case report

Cases of Kienböck's disease combined with gout are rare; to the best of our knowledge, the current report is the third such case reported in the literature. The current report presents the case of a 49-year-old male patient with Kienböck's disease combined with gout. The patient had experienced swelling and pain of their right wrist for 1 month. Through a combination of clinical history, physical examination, laboratory results, radiological and intraoperative findings, the patient was diagnosed with stage IIIB-IV Kienböck's disease and gout. The patient recovered well following a synovectomy and medication for gout. The rarity of the present case makes it difficult to examine the potential association between gout and Kienböck's disease. Kienböck's disease combined with gout tends to be ignored and is easily misdiagnosed. However, the surgical procedure selection for Kienböck's disease combined with gout is markedly different from the conventional surgery for Kienböck's disease or gout alone. The current study outlines a successful treatment strategy for gout combined with Kienbock's disease.

Combining Hyperechoic Aggregates and the Double-Contour Sign Increases the Sensitivity of Sonography for Detection of Monosodium Urate Deposits in Gout

OBJECTIVES

To compare the sensitivities of individual and combined sonography of hyperechoic aggregates and the double-contour sign in detecting monosodium urate (MSU) crystal deposits in gouty joints.

METHODS

Monosodium urate crystal deposits in symptomatic and contralateral asymptomatic joints of 70 patients with acute gout were evaluated by sonography of hyperechoic aggregates and the double-contour sign individually and in combination. All patients with acute gout in this study had at least 1 symptomatic joint with MSU deposits determined by dual-energy computed tomography.

RESULTS

Of 195 symptomatic joints (92 in the upper limbs and 103 in the lower limbs) and an equal number of asymptomatic joints: (1) 97.14% (68 of 70) of patients had hyperechoic aggregate/double-contour sign-positive joints versus 74.29% (52 of 70) with double-contour sign-positive and 63.89% (46 of 70) with hyperechoic aggregate-positive joints; (2) 86.96% (80 of 92) of the symptomatic upper limb joints were double-contour sign/hyperechoic aggregate positive versus 46.74% (43 of 92) that were double-contour sign positive and 70.65% (65 of 92) that were hyperechoic aggregate positive; and (3) 98.06% (101 of 103) of the symptomatic lower limb joints were double-contour sign/hyperechoic aggregate positive versus 92.23% (95 of 103) that were double-contour sign positive and 41.75% (43 of 103) that were hyperechoic aggregate positive.

CONCLUSIONS

Hyperechoic aggregates and the double-contour sign in combination improve the investigative sensitivity of sonography than either hyperechoic aggregates or the double-contour sign individually for detecting MSU crystal deposits in gouty joints.

Zisheng Shenqi decoction ameliorates monosodium urate crystal-induced gouty arthritis in rats through anti-inflammatory and anti-oxidative effects

Based on traditional Chinese medicinal theories on gouty arthritis, Zisheng Shenqi decoction (ZSD), a novel Chinese medicinal formula, was developed due to its multiple functions, including reinforcing renal function, promoting blood circulation and relieving pain. In the present study, the effect of ZSD on monosodium urate (MSU) crystal-induced gouty arthritis in rats was investigated and the underlying mechanisms were examined. The data from these investigations showed that the injection of MSU crystals into the ankle joint cavity caused significant elevations in ankle swelling and inflammatory cell infiltration into the synovium, whereas these abnormal changes were markedly suppressed by oral administration of ZSD (40 mg/kg) for 7 days. Mechanically, ZSD treatment prevented MSU crystal-induced inflammatory responses, as evidenced by downregulation in the expression levels of NACHT domain, leucine-rich repeat and pyrin domain containing protein (NALP) 1 and NALP6 inflammasomes, decreased serum levels of tumor necrosis factor-α and interleukin-1β, and inhibited activation of nuclear factor-κB. In addition, ZSD administration markedly enhanced the anti-oxidant status in MSU crystal-induced rats by the increase in the activities of superoxide dismutase and glutathione peroxidase, and the levels of reduced glutathione. These results indicated that ZSD effectively prevented MSU crystal-induced gouty arthritis via modulating multiple anti-oxidative and anti-inflammatory pathways, suggesting a promising herbal formula for the prevention and treatment of gouty arthritis.

Sonographic Findings in Gouty Arthritis: Diagnostic Value and Association with Disease Duration

The objective of this work was to evaluate the sonographic features of gouty arthritis and correlate findings with disease duration. The study was conducted on 100 patients in ambulatory care aged ≥40 y. Inclusion criteria included mono- or oligo-arthritis with effusion of the knee or the first metatarsophalangeal (MTP) joint and no known history of gout. A complete medical history was obtained with emphasis on the known risk factors or causes of gouty arthritis. A 12-MHz Medison linear probe was used for ultrasonography (US). Synovial fluid analysis with polarizing light microscopy was performed on all patients. Ninety-eight knee joints and 33 first MTP joints were examined. Gouty arthritis was found by US in four forms: (i) floating echogenic foci in effusion fluid or Baker cysts, (ii) deposits on the cartilage surface (double contour sign), (iii) erosions and (iv) mature tophus/tophi. These were found in 78.9%, 42.3%, 39.4% and 28.2% of patients, respectively. The overall sensitivity and specificity of US in detecting gout (as defined by the clinical gold standard, i.e., detection of urate crystals by polarizing light microscopy) were 85.9% and 86.7%, respectively. Detection of echogenic foci in effusion fluid was associated with the shortest duration of symptoms (median duration 2 y) followed by double contour sign (3.5 y), erosions (4 y) and tophus (12.5 y). Sonographic findings in gout can be assigned a temporal pattern, with echogenic foci being associated with the shortest and full tophus formation with the longest disease duration.

Gout Prophylaxis Evaluated According to the 2012 American College of Rheumatology Guidelines: Analysis from the CORRONA Gout Registry

OBJECTIVE

To analyze prophylaxis using the CORRONA (COnsortium of Rheumatology Researchers Of North America) Gout Registry according to the American College of Rheumatology (ACR) guidelines, and to evaluate whether differences in disease characteristics influenced prophylaxis.

METHODS

All patients with gout in the CORRONA Gout Registry between November 1, 2012, and November 26, 2013, were included. They were divided into 2 groups: "receiving prophylaxis" versus "not receiving prophylaxis" at the time of enrollment. Patients having a flare at time of visit were excluded. Descriptive statistics and multivariable logistic regression models were performed to evaluate the factors associated with prophylaxis.

RESULTS

There were 1049 patients with gout available for analysis. There were 441 patients (42%) receiving prophylaxis and 608 (58%) not receiving prophylaxis. The most common drugs used for prophylaxis were colchicine (78%) and nonsteroidal antiinflammatory drugs (32%). Prophylaxis drug combination was used by 45 patients (10.2%). Patients in the "receiving prophylaxis" group were more likely to have a gout duration of ≤ 1 year (n = 68, p < 0.001), ≥ 1 flare in the year previous to enrollment (p < 0.001), ≥ 1 healthcare uses in the last year [Emergency Department (p = 0.029); outpatient visit to primary care, rheumatologist, or urgent care clinic (p < 0.001)], have tophi (p < 0.001), report pain > 3 (p = 0.001), and have disease activity > 10 (p < 0.001) compared with patients in the "not receiving prophylaxis" group.

CONCLUSION

Forty-two percent of patients with gout in the CORRONA Gout Registry were receiving prophylaxis. Prophylaxis was significantly more common in patients with a higher disease burden and activity, which is in agreement with the ACR guidelines. Our study highlights disease characteristics influencing prophylaxis and furthers our knowledge on current use of flare prophylaxis.

A prospective evaluation of ultrasound as a diagnostic tool in acute microcrystalline arthritis

INTRODUCTION

The performance of ultrasound (US) in the diagnosis of acute gouty (MSU) arthritis and calcium pyrophosphate (CPP) arthritis is not yet well defined. Most studies evaluated US as the basis for diagnosing crystal arthritis in already diagnosed cases of gout and few prospective studies have been performed.

METHODS

One hundred nine consecutive patients who presented an acute arthritis of suspected microcrystalline arthritis were prospectively included. All underwent an US of the symptomatic joints(s) and of knees, ankles and 1(st) metatarsopalangeal (MTP) joints by a rheumatologist "blinded" to the clinical history. 92 also had standard X-rays. Crystal identification was the gold standard.

RESULTS

Fifty-one patients had MSU, 28 CPP and 9 had both crystals by microscopic analysis. No crystals were detected in 21. One had septic arthritis. Based on US signs in the symptomatic joint, the sensitivity of US for both gout and CPP was low (60% for both). In gout, the presence of US signs in the symptomatic joint was highly predictive of the diagnosis (PPV = 92%). When US diagnosis was based on an examination of multiple joints, the sensitivity for both gout and CPP rose significantly but the specificity and the PPV decreased. In the absence of US signs in all the joints studied, CPP arthritis was unlikely (NPV = 87%) particularly in patients with no previous crisis (NPV = 94%). X-ray of the symptomatic joints was confirmed to be not useful in diagnosing gout and was equally sensitive or specific as US in CPP arthritis.

CONCLUSIONS

Arthrocenthesis remains the key investigation for the diagnosis of microcrystalline acute arthritis. Although US can help in the diagnostic process, its diagnostic performance is only moderate. US should not be limited to the symptomatic joint. Examination of multiple joints gives a better diagnostic sensitivity but lower specificity.

Development, external validation, and comparative assessment of a new diagnostic score for hepatic steatosis

OBJECTIVES

We used data from population-based studies to determine the accuracy of the Fatty Liver Index (FLI) and the Hepatic Steatosis Index (HSI) in determining individual risk of hepatic steatosis. We also developed a new risk scoring system and validated all three indices using external data.

METHODS

We used data from the Study of Health in Pomerania (SHIP; n=4,222), conducted in North-eastern Germany, to validate the existing scoring systems and to develop our own index. Data from the South German Echinococcus Multilocularis and Internal Diseases in Leutkirch (EMIL) study (n=2,177) were used as an external validation data set. Diagnostic performance was evaluated in terms of discrimination (area under the receiver operating characteristic curve (AUC)) and calibration plots. We applied boosting for generalized linear models to select relevant diagnostic separators.

RESULTS

The FLI accurately discriminated patients with fatty liver disease from those without (AUC=0.817) but had poor calibration, in that predicted risks differed considerably from observed risks, based on SHIP data. The FLI performed well in discrimination and calibration in the analysis of EMIL data (AUC=0.890). The HSI performed worse than the FLI in analysis of both data sets (SHIP: AUC=0.782 and EMIL: AUC=0.841), showing an extremely skewed calibration. Our newly developed risk score had a good performance in the development data set (SHIP: AUC=0.860) and also good discrimination ability in the validation data (EMIL: AUC=0.876), but it had low calibration based on the validation data set.

CONCLUSIONS

We compared the ability of the FLI, HSI, and our own scoring system to determine the risk of hepatic steatosis using two population-based data sets (one for the development of our own system and one for validation). In the development and independent replication data set, all three indices discriminated well between patients with and without hepatic steatosis, but the predicted risks did not match well with the observed risks, when applied to external data. Scoring systems for fatty liver disease could depend on methodological standardization of ultrasound diagnosis and laboratory measurements.

Gouty panniculitis with ulcerations in a patient with multiple organ dysfunctions

Gouty panniculitis is a rare manifestation of gout. Clinically, it is characterized by indurated subcutaneous nodules in nonjoint areas. Pathologically, typical characteristic gouty tophi can be seen in subcutaneous tissue. It is postulated that gouty panniculitis develops as a consequence of uric acid accumulation in the body and localized inflammatory changes in subcutaneous tissue. We report a case of a 46-year-old man with 20-year history of gout, who developed multiple subcutaneous nodules over the abdomen and right groin/thigh area over a 2-year period. After a recent episode of congestive heart failure and acute renal failure, the nodules increased in size and the overlying skin became erythematous and ulcerated. Pathologic examination demonstrated typical tophi in the dermis and subcutaneous tissue. A review of the literature yielded fifteen similar cases that had been previously reported. We conclude that gouty panniculitis may be a manifestation of undertreated gout and may be exacerbated by the deterioration of other systemic functions.

Fuzzy optimization for detecting enzyme targets of human uric acid metabolism

MOTIVATION

Mathematical modeling and optimization have been used for detecting enzyme targets in human metabolic disorders. Such optimal drug design methods are generally differentiated as two stages, identification and decision-making, to find optimal targets. We developed a unified method named fuzzy equal metabolic adjustment to formulate an optimal enzyme target design problem for drug discovery. The optimization framework combines the identification of enzyme targets and a decision-making strategy simultaneously. The objectives of this algorithm include evaluations of the therapeutic effect of target enzymes, the adverse effects of drugs and the minimum effective dose (MED).

RESULTS

An existing generalized mass action system model of human uric acid (UA) metabolism was used to formulate the fuzzy optimization method for detecting two types of enzymopathies: hyperuricemia caused by phosphoribosylpyrophosphate synthetase (PRPPS) overactivity and Lesch-Nyhan syndrome. The fuzzy objectives were set so that the concentrations of the metabolites were as close as possible to the healthy levels. The target design included a diet control of ribose-5-phospahate (R5P). The diet control of R5P served as an extra remedy to reduce phosphate uptake entering the purine metabolic pathway, so that we could obtain a more satisfactory treatment than obtained for those without a diet control. Moreover, enhancing UA excretion resulted in an effective treatment of hyperuricemia caused by PRPPS overactivity. This result correlates with using probenecid and benbromazone, which are uricosuric agents present in current clinical medications. By contrast, the Lesch-Nyhan syndrome required at least three enzyme targets to cure hyperuricemia.

Current concepts in the treatment of gouty arthritis

Gouty arthritis is an extremely painful condition that causes functional impairment. Gouty arthritis has become increasingly complex because of multiple comorbidities, iatrogenic factors and hyperuricemia that is refractory to treatment. In this review, we present a general overview of gouty arthritis including its pathophysiology, clinical presentations, diagnosis, predisposing factors and prophylactic therapy for preventing gouty arthritis flares.

Effects of Extract from Mangifera indica Leaf on Monosodium Urate Crystal-Induced Gouty Arthritis in Rats

The leaves of Mangifera indica L. (Anacardiaceae) is used as a medicinal material in traditional herb medicine for a long time in India, China, and other Eastern Asian countries. Our present study investigated the therapeutic effects of the ethanol extract from Mangifera indica (EMI) in rat with monosodium urate (MSU) crystals-induced gouty arthritis. Effects of EMI (50, 100, and 200 mg/kg, p.o.) administrated for 9 days on the ankle swelling, synovial tumor necrosis factor-alpha (TNF-α), and interleukin-1beta (IL-1β) levels were assessed in MSU crystal rat. Data from our study showed that rat with gouty arthritis induced by MSU crystal demonstrated an elevation in ankle swelling, synovial TNF-α, IL-1β mRNA, and protein levels. Oral administration of 100 and 200 mg/kg EMI for 9 days reversed the abnormalities in ankle swelling, synovial TNF-α, IL-1β mRNA, and protein levels. The results indicated that the beneficial antigouty arthritis effect of EMI may be mediated, at least in part, by inhibiting TNF-α and IL-1β expression in the synovial tissues. Our study suggests that Mangifera indica and its extract may have a considerable potential for development as an anti-gouty arthritis agent for clinical application.

Treatment of chronic gouty arthritis: it is not just about urate-lowering therapy

OBJECTIVES

The management of gouty arthritis is focused on treating pain and inflammation associated with acute flares and preventing further acute flares and urate crystal deposition. A challenge associated with the successful management of gouty arthritis is an increased risk of acute flares during the first months after initiation of urate-lowering therapy (ULT). This increase in flare frequency can occur regardless of the choice of ULT and is linked to suboptimal patient adherence to ULT. Current treatment recommendations for the use of prophylaxis are limited. There are no definitive recommendations as to which agents should be used or for how long therapy is beneficial after starting ULT. This article aims to improve awareness of the importance of gouty arthritis flare prophylaxis when initiating ULT and to summarize current recommendations and clinical findings related to the efficacy and safety of currently available and investigational new therapies.

METHODS

This review discusses the pathophysiology of acute gouty arthritis flares during initiation of ULT and examines the literature on the use of anti-inflammatory prophylaxis for reduction of these flares.

RESULTS

It has recently become clear that, even when the patient is asymptomatic, chronic inflammation is often present in patients with chronic gouty arthritis. Chronic anti-inflammatory therapy should therefore be added to chronic ULT. Prophylaxis with colchicine as well as with nonsteroidal anti-inflammatory drugs (NSAIDs) during ULT initiation can reduce the incidence and severity of gouty arthritis flares substantially; however, safety concerns associated with colchicine and NSAIDs may limit their use.

CONCLUSION

When colchicine and NSAIDs are contraindicated or poorly tolerated, rilonacept and canakinumab, interleukin-1 inhibitors in trials, may prove to be useful alternatives for flare prevention. (Of note, although both inhibit the IL-1β pathway, rilonacept also binds to IL-1α and IL-1RA, in contrast to canakinumab, which binds selectively to IL-1β.).

Giant gouty tophi of the hand and wrist

Gout is an inflammatory-rheumatic disease characterized by an elevated serum urate concentration and recurrent flares, including painful, hot, red, and swollen joints and surrounding tissue. Untreated gout often develops into a chronic disease with tophi and destruction of joint surfaces. Giant tophi are often resistant to medication and change in diet.This article presents a case of a 44-year-old man with giant gouty tophi at his hand and wrist. The last acute gout flare in his left wrist was approximately 3 years prior. For 2 years he had refused adequate nutrition, such as a low-purine diet, and had refused to take any preventive medication. Blood urate level was elevated to 8.7 mg/dL (normal range, 3.4-7.0 mg/dL). In time, the tophi led to a massive limitation of motion and use of especially the left wrist and thumb. Under the condition that the patient changed his diet and took the medication for his underlying disease, we surgically removed the almost skin-perforating tophi. Surgical debulking significantly improved joint function and cosmetic appearance.The best treatment for gouty tophi is prevention by ensuring adequate nutrition, treating the underlying causes, and taking effective medication. In the case of massive limitation of joint motion, skin breakdown with risk of infection, and compression of neurovascular structures, surgical debulking of the tophi should be considered.

Canakinumab reduces the risk of acute gouty arthritis flares during initiation of allopurinol treatment: results of a double-blind, randomised study

OBJECTIVE

This study assessed the efficacy and safety of canakinumab, a fully human anti-interleukin 1β monoclonal antibody, for prophylaxis against acute gouty arthritis flares in patients initiating urate-lowering treatment.

METHODS

In this double-blind, double-dummy, dose-ranging study, 432 patients with gouty arthritis initiating allopurinol treatment were randomised 1:1:1:1:1:1:2 to receive: a single dose of canakinumab, 25, 50, 100, 200, or 300 mg subcutaneously; 4×4-weekly doses of canakinumab (50+50+25+25 mg subcutaneously); or daily colchicine 0.5 mg orally for 16 weeks. Patients recorded details of flares in diaries. The study aimed to determine the canakinumab dose having equivalent efficacy to colchicine 0.5 mg at 16 weeks.

RESULTS

A dose-response for canakinumab was not apparent with any of the four predefined dose-response models. The estimated canakinumab dose with equivalent efficacy to colchicine was below the range of doses tested. At 16 weeks, there was a 62% to 72% reduction in the mean number of flares per patient for canakinumab doses ≥50 mg versus colchicine based on a negative binomial model (rate ratio: 0.28-0.38, p≤0.0083), and the percentage of patients experiencing ≥1 flare was significantly lower for all canakinumab doses (15% to 27%) versus colchicine (44%, p<0.05). There was a 64% to 72% reduction in the risk of experiencing ≥1 flare for canakinumab doses ≥50 mg versus colchicine at 16 weeks (hazard ratio (HR): 0.28-0.36, p≤0.05). The incidence of adverse events was similar across treatment groups.

CONCLUSIONS

Single canakinumab doses ≥50 mg or four 4-weekly doses provided superior prophylaxis against flares compared with daily colchicine 0.5 mg.