Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0018099 (gout)
 5,192 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Xanthine oxidase is a flavoprotein enzyme which catalyzes the oxidative hydroxylation of purine substrates. Because of its availability, it has become a model for structural molybdoenzymes in general. The enzyme is a well-established target of drugs against gout and hyperuricemia and exists in two forms: oxidase and deshydrogenase. In some pathologies, its level increases in oxidase form, being the source of free radicals which can cause damage to surrounding tissues. It is important to understand the mechanisms of the enzyme inhibition to help in the search of new inhibitors. The main active center is a molybdopterin buried in a cavity. Theoretical calculations can be of some help for distinguishing the important aspects in the inhibition: attraction inside the cavity and anchorage. In this paper, the molybdopterin molecule geometry has been optimized by ab initio with the DFT method and the results have been shown to be very similar to the X-ray coordinates. In order to evaluate the attraction inside the cavity, the electrostatic potential between the charged molybdopterin molecule and two series of inhibitors, some flavonoids, and some gallic acid derivatives have been calculated using the multipolar development supplied by the Gaussian package. The good concordance between the electrostatic force and IC(50) indicates that the attraction is an important factor in the inhibition and must be taken into account in the designing of new drugs.
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PMID:Theoretical study of the mechanism of inhibition of xanthine oxidase by flavonoids and gallic acid derivatives. 2003 Apr 6

Gout is the most common inflammatory arthritis in an elderly population, and can be diagnosed with absolute certainty by polarization microscopy. However, diagnosis may be challenging because atypical presentations are more common in the elderly. Management of hyperuricemia in the elderly with gout requires special consideration because of co-medication, contra-indications, and risk of adverse reactions. Urate-lowering agents include allopurinol and uricosuric agents. These also must be used sensibly in the elderly, especially when renal function impairment is present. However, if used at the lowest dose that maintains the serum urate level below 5.0 to 6.0 mg/dL (0.30 to 0.36 mmol/L), the excess urate in the body will eventually be eliminated, acute flares will no longer occur, and tophi will resolve. Febuxostat, a new xanthine oxidase inhibitor, is welcomed, as few alternatives for allopurinol are available. Its pharmacokinetics and pharmacodynamics are not significantly altered in patients with moderate renal function or hepatic impairment. Its antihyperuricemic efficacy at 80 to 120 mg/day is better than "standard dosage" allopurinol (300 mg/day). Long-term safety data and efficacy data on tophus diminishment and reduction of gout flares have recently become available. Febuxostat may provide an important option in patients unable to use allopurinol, or refractory to allopurinol.
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PMID:Management of hyperuricemia in gout: focus on febuxostat. 2016 38

Uric acid (UA) results from xanthine oxidase (XO) catabolism of xanthine and is the final product of purine catabolism in humans. In this species, hyperuricemia is associated with gout, nephropathy, and increased cardiovascular disease risk. Although the effects of hyperuricemia in vascular biology are overall controversial, UA has been described as an antioxidant and as potentially improving endothelial function. Hypertension is associated with endothelial dysfunction. We hypothesized that UA improves the endothelial function of aorta from deoxycorticosterone acetate (DOCA)-salt hypertensive rats. UA (100 microM) in the presence of the uricase inhibitor oxonic acid (10 microM) did not modify relaxation to acetylcholine (ACh) (1 nM-10 microM) in the aorta from nontreated, sham normotensive, and DOCA-salt hypertensive rats [response to 10 microM ACh for UA versus vehicle, respectively: nontreated = 37 +/- 7 versus 48 +/- 7%, sham = 53 +/- 15 versus 57 +/- 20%, DOCA = 81 +/- 4 versus 85 +/- 2% from 20 microM prostaglandin 2alpha (PGF(2alpha))-induced contraction]. Allopurinol (100 microM), a XO inhibitor, did not significantly alter the ACh-induced relaxation of sham and DOCA aortic rings (response to 10 microM ACh for allopurinol versus vehicle, respectively: sham = 61 +/- 5 versus 68 +/- 9%, DOCA = 87 +/- 6 versus 88 +/- 3% from 20 microM PGF(2alpha)-induced contraction). Uricemia, ranging from unmeasurable to 547 microM in sham and to 506 microM in DOCA rats, was not significantly different between these two groups. The expression and activity of XO, as well as the expression of uricase, were not different between sham and DOCA rat aorta. We conclude that, at least in vitro, UA does not affect the ACh-induced relaxation of normotensive and DOCA-salt hypertensive rats.
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PMID:Uric acid does not affect the acetylcholine-induced relaxation of aorta from normotensive and deoxycorticosterone acetate-salt hypertensive rats. 2021 10

This position paper aims to clarify the presumed place of febuxostat in the management of gout patients. Since this novel xanthine oxidase inhibitor is now available, an international group of gout experts decided to formulate an international consensus statement. This statement presents the place for this new xanthine oxidase inhibitor in the treatment of gout which may contribute to optimize treatment of gout patients in Europe and worldwide.
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PMID:International position paper on febuxostat. 2040 6

Hyperuricemia is a condition of defective purine metabolism characterized with elevated serum uric acid (UA) level that further leads to gout and gouty nephrolithiasis disorders. Gout is a world wide distributed rheumatic disease comprises 1% of the total population and still is in increasing state. One of the factors contributing to overproduction of UA is the hydroxylation of xanthine catalyzed by xanthine oxidase (XO). In the present study, 3D modeling of Arthrobacter sp. XL26 (xodB) protein was performed by comparative modeling approach using Rhodobacter capsulatus XDH (PDB ID: 2W3sF) as template in SWISS-MODEL, Geno3D and MODELLER program server. The best model was selected based on overall stereochemical quality (Procheck, PROSA, GenThreader), energy minimized, refined and used for active site characterization in BioMed CAChe workspace. The enzyme-inhibitor interaction was studied by docking to screen the possible inhibitors and application of model in design and development of anti-gout agents.
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PMID:Homology modeling and docking study of xanthine oxidase of Arthrobacter sp. XL26. 2040 78

Gout is a disorder of purine metabolism, of varied etiology, associated with an increase in serum uric acid and a recurrent arthritis. The defect may be either metabolic or renal, or either unknown etiology or associated with other disease states. The acute arthritis has been shown to be due to a crystal (sodium urate) synovitis. The many chronic complications, arthritic, renal and vascular, necessitate a vigorous and longterm treatment program. With the advent of the xanthine oxidase inhibiter Allopurinol, excellent control of gout and its complications can be achieved in a large number of patients, with good control in the remainder.
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PMID:Gout: current concepts and treatment. 2046 63

Gout is a common, painful, and often debilitating rheumatologic disorder that remains one of the few arthritic conditions that can be diagnosed with certainty and cured with appropriate therapy. Allopurinol is the most frequently prescribed agent for gout in the United States. Unfortunately, most patients treated with allopurinol do not achieve target serum uric acid (sUA) levels, possibly due to a perceived intolerability to allopurinol in doses above 300 mg and the need for reduced doses in patients with renal insufficiency. Febuxostat, an orally administered, nonpurine inhibitor of xanthine oxidase, was recently approved by the U.S. Food and Drug administration for chronic management of hyperuricemia in patients with gout. Patients treated with febuxostat achieve rapid and substantial reductions in sUA levels. Compared with allopurinol-treated patients, patients receiving febuxostat 80 mg/day were more likely to achieve sUA concentrations less than 6 mg/dl. In long-term studies (up to 5 yrs), febuxostat demonstrated sustained reductions in sUA levels, nearly complete elimination of gout flares, and a frequency of adverse effects comparable to allopurinol. The most commonly reported adverse effects were liver function abnormalities, rash, nausea, and arthralgias. The recommended starting dose of febuxostat is 40 mg/day, which may be increased to 80 mg/day after 2 weeks if patients do not achieve sUA levels less than 6 mg/dl. Dosage adjustment in mild-to-moderate renal insufficiency is unnecessary; however, data are lacking on the safety of febuxostat in patients with severe renal impairment. Although more costly than allopurinol, febuxostat appears to be an acceptable alternative for the treatment of gout and hyperuricemia, and may be advantageous in patients with renal impairment, intolerance to allopurinol, or the inability to attain sUA levels less than 6 mg/dl despite adequate therapy with available agents.
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PMID:Urate-lowering therapy for gout: focus on febuxostat. 2050 48

In order to further understand and assess the validity of herbal medicine, we investigated the potential inhibitory effect of various extracts from Fraxinus angustifolia and Pistacia lentiscus, two plants used traditionally in Algeria against several inflammatory diseases such as rheumatism, arthritis, and gout, on purified bovine milk xanthine oxidase (XO) activity. The total phenolic contents of the leaves and bark of F. angustifolia and the leaves and seeds of P. lentiscus were estimated. P. lentiscus aqueous fractions from hexane and chloroform extractions and F. angustifolia aqueous fraction from ethyl acetate extraction inhibited XO activity by 72.74 +/- 2.63% (50% inhibitory concentration [IC(50)] = 27.52 microg/mL), 68.97 +/- 3.89% (IC(50) = 42.46 microg/mL) and 53.92 +/- 3.17% (IC(50) = 58.84 mmicroug/mL), respectively, at 100 microg/mL, compared to that of reference drug, allopurinol (98.18% [IC(50) = 6.34 microg/mL]). Moreover, at a concentration of 50 microg/mL, both P. lentiscus extracts showed inhibition rates higher than 50%. F. angustifolia leaf extracts showed only mild inhibition. Lineweaver-Burk analysis showed that the inhibitory activity exerted by F. angustifolia bark aqueous extract and P. lentiscus aqueous extracts is of mixed type, whereas the leaf extracts from F. angustifolia inhibited XO noncompetitively. Positive correlations were established between XO inhibition and total phenols (r = 0.89) and flavonoids (r = 0.93) for P. lentiscus and with total phenols (r = 0.72) and tannins (r = 0.54) for F. angustifolia. Our findings suggest that the therapeutic use of these plants may be due to the observed XO inhibition, thereby supporting their use in traditional folk medicine against inflammatory-related diseases, in particular, gout.
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PMID:Kinetic study on the inhibition of xanthine oxidase by extracts from two selected Algerian plants traditionally used for the treatment of inflammatory diseases. 2055 85

The prevalence of gout in the western countries is 1-2%. The disease has become more common during the last two decades, and the same time its clinical picture has changed. The disease is often polyarticular, the patients are older than before and they have more often associated cardiovascular diseases and renal insufficiency. Effective treatment of acute gout is nonsteroidal anti-inflammatory drugs with intra-articular or systematic corticosteroids. The goal for the treatment of intermittent and chronic gout is to maintain serum urate concentration velow 360 micromol/l by diet and by antihyperuricemic meditation, primarly allopurinole and probenecid. Febuxostat is a new xanthine oxidase inhibitor, which will be available for the treatment of refractory gout in the near future. Special attention should be paid on detecting and treating cardiovascular diseases and their risk factors in patients with gout.
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PMID:[The clinical picture of gout is changing]. 2061 51

Around 1.4% of the UK population have gout, the prevalence of which increases with age to around 3% in women and 7% in men aged over 75 years. Acute gout is intensely painful and can reduce patients' quality of life. It occurs when the serum uric acid concentration (SUA) rises (hyperuricaemia) and persists above the solubility threshold of monosodium urate (400 micromol/L [6.8 mg/dL]), leading to urate crystal formation that causes arthritis, gouty tophi (nodules) in subcutaneous tissues and renal calculi. The mainstay of treatment for chronic gout is allopurinol, which inhibits xanthine oxidase (an enzyme involved in the production of uric acid in the body). However, this drug has to be stopped in a minority of patients due to rashes or hypersensitivity. Febuxostat (Adenuric - Menarini/Ipsen), another xanthine oxidase inhibitor, is a newly licensed treatment for chronic hyperuricaemia in conditions where urate deposition has occurred. Here we consider its place for patients with gout.
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PMID:Febuxostat for gout. 2063 Nov 96


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