Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An acute attack of gouty arthritis is one of the most painful experiences reported throughout medical history. Therefore it is paramount to initiate appropriate therapy quickly in order to terminate the acute phase. This goal can be achieved with non-steroidal anti-inflammatory agents, colchicine, or corticosteroid-based therapies. Rarely, because of contraindications to these agents, only symptomatic treatment can be given until the attack subsides. The next step is to lower the serum urate level below the limit of solubility (i.e., below 40.8 mmol/L, or 6.8mg/dL) which reduces recurrences and begins to return the total body urate pool to normal. This equally important goal can be achieved by uricosuric agents or xanthine oxidase inhibitors, although the latter is generally favored. Allopurinol is the agent most commonly preferred because of its safety profile and ease of use, but there are known serious allergic reactions and untoward side effects that occasionally require discontinuation. Febuxostat, a xanthine oxidase inhibitor, and pegylated uricase are new agents under development and may be beneficial in these situations or when other comorbid conditions prevent the use of conventional treatments. Alcohol and dietary consumption are also related to hyperuricemia and acute gout. Recently beer, wine, and liquor were studied and the risk of gout varied according to the alcohol ingested. Furthermore, recent data sheds light on important dietary modifications that may help in the treatment of gout, and dispels certain beliefs about protein ingestion and the occurrence of acute gout. As we learn more about the associated conditions of hypertriglyceridemia, hypertension, and the metabolic syndrome, it may allow the tailoring of medical regimens that directly prevent or reduce recurrent attacks of gouty arthritis. There are specific approved treatments for these common comorbidities that have parallel effects of lowering serum urate levels. These recent findings may be especially important for treating refractory cases. While patient education remains a cornerstone to ensure compliance, other quality indicators for the management of this disease have been reported and should guide the clinician in the treatment of gout and result in improved care.
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PMID:Advances in the management of gout and hyperuricaemia. 1688 87

Recent epidemiological studies provide a clear evidence that hyperuricemia is associated with hypertension, coronary heart disease, left ventricular hypertrophy and progression of renal disease. Aim of our study was to assess the effect of low dosage of recombinant urate oxidase on hyperuricemia in renal failure patients that already receiving allopurinol. Our study group consisted of 43 renal failure patients, 23 women and 20 men. The mean age was 74 years (range 36-90 years). The following variables were studied on admission: serum creatinine, blood urea nitrogen and serum uric acid. Intravenous rasburicase was administered at a dose of 0.02 mg/kg/day on 3 consecutive days in patients with serum uric acid between 8-10 mg/dl, on 5 consecutive days in patients with serum uric acid between 10-15 mg/dl and on 7 consecutive days in patients with serum uric acid > 15 mg/dl. Uric acid levels were assayed after 48 hours and 7 days after rasburicase treatment. Mean values of uric acid levels after 48 hours were 2.47 mg/dl (+/- 1.58) in men and 2.77 mg/dl (+/- 2.24) in woman, where'as mean values of uric acid levels after 7 days were 4.45 mg/dl (+/- 2.0) in men and 5.75 mg/dl (+/- 1.9) in woman. No significant relationship were found between uric acid and creatinine as before as well after therapy. There were no side effects in all patients included in the study. After 7 days, the rasburicase therapy showed more antihyperuricemic effect in men (59%) than in women (46%).
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PMID:Is rasburicase an effective alternative to allopurinol for management of hyperuricemia in renal failure patients? A double blind-randomized study. 1797 Feb 34

Humans have relatively low plasma ascorbate levels and high serum uric acid levels compared to most mammals due to the presence of genetic mutations in l-gulonolactone oxidase and uricase, respectively. We review the major hypotheses for why these mutations may have occurred. In particular, we suggest that both mutations may have provided a survival advantage to early primates by helping maintain blood pressure during periods of dietary change and environmental stress. We further propose that these mutations have the inadvertent disadvantage of increasing our risk for hypertension and cardiovascular disease in today's society characterized by Western diet and increasing physical inactivity. Finally, we suggest that a "planetary biology" approach in which genetic changes are analyzed in relation to their biological action and historical context may provide the ideal approach towards understanding the biology of the past, present and future.
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PMID:The planetary biology of ascorbate and uric acid and their relationship with the epidemic of obesity and cardiovascular disease. 1833 82

Endothelial dysfunction is a characteristic feature during the renal damage induced by mild hyperuricemia. The mechanism by which uric acid reduces the bioavailability of intrarenal nitric oxide is not known. We tested the hypothesis that oxidative stress might contribute to the endothelial dysfunction and glomerular hemodynamic changes that occur with hyperuricemia. Hyperuricemia was induced in Sprague-Dawley rats by administration of the uricase inhibitor, oxonic acid (750 mg/kg per day). The superoxide scavenger, tempol (15 mg/kg per day), or placebo was administered simultaneously with the oxonic acid. All groups were evaluated throughout a 5-wk period. Kidneys were fixed by perfusion and afferent arteriole morphology, and tubulointerstitial 3-nitrotyrosine, 4-hydroxynonenal, NOX-4 subunit of renal NADPH-oxidase, and angiotensin II were quantified. Hyperuricemia induced intrarenal oxidative stress, increased expression of NOX-4 and angiotensin II, and decreased nitric oxide bioavailability, systemic hypertension, renal vasoconstriction, and afferent arteriolopathy. Tempol treatment reversed the systemic and renal alterations induced by hyperuricemia despite equivalent hyperuricemia. Moreover, because tempol prevented the development of preglomerular damage and decreased blood pressure, glomerular pressure was maintained at normal values as well. Mild hyperuricemia induced by uricase inhibition causes intrarenal oxidative stress, which contributes to the development of the systemic hypertension and the renal abnormalities induced by increased uric acid. Scavenging of the superoxide anion in this setting attenuates the adverse effects induced by hyperuricemia.
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PMID:Role of oxidative stress in the renal abnormalities induced by experimental hyperuricemia. 1870 32

In humans, uric acid is the main urinary metabolite of purines. Serum levels are higher compared with other mammalians. Uric acid is an antioxidant and perhaps helps to control blood pressure during a low Na+ diet through stimulation of the renin-angiotensin system. Serum uric acid is also considered a marker of tubular reabsorption and 'effective' circulating blood volume. Moreover, hyperuricemia seems to be a cofactor in Na+ -sensitive hypertension, a marker and possibly itself responsible for microvascular damage through stimulation of the renin-angiotensin system, inhibition of endothelial nitric oxide, and proliferative effects on vascular smooth muscle. As fructose-rich diets increase uric acid levels, hyperuricemia may also play a role in the metabolic syndrome, triggering insulin resistance and hypertension.A number of studies on rats rendered hyperuricemic by administration of uricase inhibitors have recently confirmed induction of arterial hypertension and microvascular injury, particularly in the remnant kidney or in cyclosporine-induced renal fibrosis.
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PMID:Uric acid: bystander or culprit in hypertension and progressive renal disease? 1885 44

Gout is the most common form of inflammatory arthritis in the elderly. In the last two decades, both hyperuricemia and gout have increased markedly and similar trends in the epidemiology of the metabolic syndrome have been observed. Recent studies provide new insights into the transporters that handle uric acid in the kidney as well as possible links between these transporters, hyperuricemia, and hypertension. The treatment of established hyperuricemia has also seen new developments. Febuxostat and PEG-uricase are two novel treatments that have been evaluated and shown to be highly effective in the management of hyperuricemia, thus enlarging the therapeutic options available to lower uric acid levels. Monosodium urate (MSU) crystals are potent inducers of inflammation. Within the joint, they trigger a local inflammatory reaction, neutrophil recruitment, and the production of pro-inflammatory cytokines as well as other inflammatory mediators. Experimentally, the uptake of MSU crystals by monocytes involves interactions with components of the innate immune system, namely Toll-like receptor (TLR)-2, TLR-4, and CD14. Intracellularly, MSU crystals activate multiple processes that lead to the formation of the NALP-3 (NACHT, LRR, and pyrin domain-containing-3) inflammasome complex that in turn processes pro-interleukin (IL)-1 to yield mature IL-1 beta, which is then secreted. The inflammatory effects of MSU are IL-1-dependent and can be blocked by IL-1 inhibitors. These advances in the understanding of hyperuricemia and gout provide new therapeutic targets for the future.
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PMID:Developments in the scientific and clinical understanding of gout. 1894 74

This work develops and validates an electrochemical approach for uric acid (UA) determinations in both endogenous (cell lysate) and physiological (serum) samples. This approach is based on the electrocatalytic reduction of enzymatically generated H(2)O(2) at the biosensor of uricase-thionine-single-walled carbon nanotube/glassy carbon (UOx-Th-SWNTs/GC) with the use of Th-SWNTs nanostructure as a mediator and an enzyme immobilization matrix. The biosensor, which was fabricated by immobilizing UOx on the surface of Th-SWNTs, exhibited a rapid response (ca. 2 s), a low detection limit (0.5 +/- 0.05 microM), a wide linear range (2 microM to 2 mM), high sensitivity (approximately 90 microA mM(-1) cm(-2)), as well as good stability and repeatability. In addition, the common interfering species, such as ascorbic acid, 3,4-dihydroxyphenylacetic acid, 4-acetamidophenol, etc., did not cause any interference due to the use of a low operating potential (-400 mV vs saturated calomel electrode). Therefore, this work has demonstrated a simple and effective sensing platform for selective detection of UA in the physiological levels. In particular, the developed approach could be very important and useful to determine the relative role of endogenous and physiological UA in various conditions such as hypertension and cardiovascular disease.
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PMID:Low-potential detection of endogenous and physiological uric acid at uricase-thionine-single-walled carbon nanotube modified electrodes. 2016 56

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

The evolutionary loss of hepatic urate oxidase (uricase) has resulted in humans with elevated serum uric acid (urate). Uricase loss may have been beneficial to early primate survival. However, an elevated serum urate has predisposed man to hyperuricemia, a metabolic disturbance leading to gout, hypertension, and various cardiovascular diseases. Human serum urate levels are largely determined by urate reabsorption and secretion in the kidney. Renal urate reabsorption is controlled via two proximal tubular urate transporters: apical URAT1 (SLC22A12) and basolateral URATv1/GLUT9 (SLC2A9). In contrast, the molecular mechanism(s) for renal urate secretion remain unknown. In this report, we demonstrate that an orphan transporter hNPT4 (human sodium phosphate transporter 4; SLC17A3) was a multispecific organic anion efflux transporter expressed in the kidneys and liver. hNPT4 was localized at the apical side of renal tubules and functioned as a voltage-driven urate transporter. Furthermore, loop diuretics, such as furosemide and bumetanide, substantially interacted with hNPT4. Thus, this protein is likely to act as a common secretion route for both drugs and may play an important role in diuretics-induced hyperuricemia. The in vivo role of hNPT4 was suggested by two hyperuricemia patients with missense mutations in SLC17A3. These mutated versions of hNPT4 exhibited reduced urate efflux when they were expressed in Xenopus oocytes. Our findings will complete a model of urate secretion in the renal tubular cell, where intracellular urate taken up via OAT1 and/or OAT3 from the blood exits from the cell into the lumen via hNPT4.
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PMID:Human sodium phosphate transporter 4 (hNPT4/SLC17A3) as a common renal secretory pathway for drugs and urate. 2081 Jun 51

Gout is a condition presenting with inflammatory arthritis caused by crystallization and phagocytosis of monosodium urate in synovial fluid. It is the most common form of arthritis in men above the age of 40 years. Four clinical stages of gout have been distinguished: asymptomatic hyperuricemia, acute gouty arthritis, intercritical gout, and chronic gout. Experimental and epidemiologic studies provide growing evidence that hyperuricemia is not only the driving force behind symptoms attributed to the deposition of monosodium urate in the musculoskeletal system but also the important etiological factor in common morbidities of modern societies such as arterial hypertension, cardiovascular disease, chronic kidney disease, and type 2 diabetes mellitus. Today, the majority of gout cases demonstrate clinical features of the metabolic syndrome. Recommendations of the European League Against Rheumatism (EULAR) published in 2006 address key issues in the diagnosis of gout, as well as in the nonpharmacologic and pharmacologic management with regard to the clinical condition and comorbidities of the individual patient. Routinely used antihyperuricemic drugs include allopurinol, colchicine, and uricosuric agents. New agents have recently been introduced into clinical practice, like pegylated uricase and febuxostat, a nonpurine inhibitor analog of xanthine oxidase. Thus, novel therapeutic options are now available to combat this chronic illness which often leads to significant disability.
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PMID:[Gout and comorbidities associated with hyperuricemia]. 2136 38


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