RESUMO
Abstract Hyperuricemia is common in chronic kidney disease (CKD) and may be present in 50% of patients presenting for dialysis. Hyperuricemia can be secondary to impaired glomerular filtration rate (GFR) that occurs in CKD. However, hyperuricemia can also precede the development of kidney disease and predict incident CKD. Experimental studies of hyperuricemic models have found that both soluble and crystalline uric acid can cause significant kidney damage, characterized by ischemia, tubulointerstitial fibrosis, and inflammation. However, most Mendelian randomization studies failed to demonstrate a causal relationship between uric acid and CKD, and clinical trials have had variable results. Here we suggest potential explanations for the negative clinical and genetic findings, including the role of crystalline uric acid, intracellular uric acid, and xanthine oxidase activity in uric acid-mediated kidney injury. We propose future clinical trials as well as an algorithm for treatment of hyperuricemia in patients with CKD.
Resumo A hiperuricemia é comum na doença renal crônica (DRC) e pode estar presente em até 50% dos pacientes que se apresentam para diálise. A hiperuricemia pode ser secundária ao comprometimento da taxa de filtração glomerular (TFG) que ocorre na DRC. No entanto, ela também pode preceder o desenvolvimento da doença renal e mesmo prever uma DRC incidente. Estudos experimentais de modelos hiperuricêmicos descobriram que tanto o ácido úrico solúvel quanto o cristalino podem causar danos renais significativos, caracterizados por isquemia, fibrose tubulointersticial e inflamação. Entretanto, a maioria dos estudos de randomização Mendeliana falhou em demonstrar uma relação causal entre o ácido úrico e a DRC, e os ensaios clínicos têm apresentado resultados variáveis. Aqui sugerimos explicações potenciais para os achados clínicos e genéticos negativos, incluindo o papel do ácido úrico cristalino, do ácido úrico intracelular e da atividade da xantina oxidase na lesão renal mediada por ácido úrico. Propomos ensaios clínicos futuros, bem como um algoritmo para o tratamento de hiperuricemia em pacientes com DRC.
Assuntos
Humanos , Hiperuricemia/complicações , Insuficiência Renal Crônica/complicações , Insuficiência Renal Crônica/terapia , Ácido Úrico , Diálise Renal , Taxa de Filtração GlomerularRESUMO
Hyperuricemia is common in chronic kidney disease (CKD) and may be present in 50% of patients presenting for dialysis. Hyperuricemia can be secondary to impaired glomerular filtration rate (GFR) that occurs in CKD. However, hyperuricemia can also precede the development of kidney disease and predict incident CKD. Experimental studies of hyperuricemic models have found that both soluble and crystalline uric acid can cause significant kidney damage, characterized by ischemia, tubulointerstitial fibrosis, and inflammation. However, most Mendelian randomization studies failed to demonstrate a causal relationship between uric acid and CKD, and clinical trials have had variable results. Here we suggest potential explanations for the negative clinical and genetic findings, including the role of crystalline uric acid, intracellular uric acid, and xanthine oxidase activity in uric acid-mediated kidney injury. We propose future clinical trials as well as an algorithm for treatment of hyperuricemia in patients with CKD.
Assuntos
Hiperuricemia , Insuficiência Renal Crônica , Taxa de Filtração Glomerular , Humanos , Hiperuricemia/complicações , Diálise Renal , Insuficiência Renal Crônica/complicações , Insuficiência Renal Crônica/terapia , Ácido ÚricoRESUMO
The association between increased serum urate and hypertension has been a subject of intense controversy. Extracellular uric acid drives uric acid deposition in gout, kidney stones, and possibly vascular calcification. Mendelian randomization studies, however, indicate that serum urate is likely not the causal factor in hypertension although it does increase the risk for sudden cardiac death and diabetic vascular disease. Nevertheless, experimental evidence strongly suggests that an increase in intracellular urate is a key factor in the pathogenesis of primary hypertension. Pilot clinical trials show beneficial effect of lowering serum urate in hyperuricemic individuals who are young, hypertensive, and have preserved kidney function. Some evidence suggest that activation of the renin-angiotensin system (RAS) occurs in hyperuricemia and blocking the RAS may mimic the effects of xanthine oxidase inhibitors. A reduction in intracellular urate may be achieved by lowering serum urate concentration or by suppressing intracellular urate production with dietary measures that include reducing sugar, fructose, and salt intake. We suggest that these elements in the western diet may play a major role in the pathogenesis of primary hypertension. Studies are necessary to better define the interrelation between uric acid concentrations inside and outside the cell. In addition, large-scale clinical trials are needed to determine if extracellular and intracellular urate reduction can provide benefit hypertension and cardiometabolic disease.
Assuntos
Hipertensão/sangue , Ácido Úrico/sangue , Animais , Ensaios Clínicos como Assunto , Humanos , Hipertensão/tratamento farmacológico , Hipertensão/epidemiologia , Hipertensão/etiologia , Análise da Randomização Mendeliana , Uricosúricos/uso terapêuticoRESUMO
Urate is a cause of gout, kidney stones, and acute kidney injury from tumor lysis syndrome, but its relationship to kidney disease, cardiovascular disease, and diabetes remains controversial. A scientific workshop organized by the National Kidney Foundation was held in September 2016 to review current evidence. Cell culture studies and animal models suggest that elevated serum urate concentrations can contribute to kidney disease, hypertension, and metabolic syndrome. Epidemiologic evidence also supports elevated serum urate concentrations as a risk factor for the development of kidney disease, hypertension, and diabetes, but differences in methodologies and inpacts on serum urate concentrations by even subtle changes in kidney function render conclusions uncertain. Mendelian randomization studies generally do not support a causal role of serum urate in kidney disease, hypertension, or diabetes, although interpretation is complicated by nonhomogeneous populations, a failure to consider environmental interactions, and a lack of understanding of how the genetic polymorphisms affect biological mechanisms related to urate. Although several small clinical trials suggest benefits of urate-lowering therapies on kidney function, blood pressure, and insulin resistance, others have been negative, with many trials having design limitations and insufficient power. Thus, whether uric acid has a causal role in kidney and cardiovascular diseases requires further study.
Assuntos
Injúria Renal Aguda/epidemiologia , Doenças Cardiovasculares/epidemiologia , Educação/organização & administração , Hipertensão/epidemiologia , Hiperuricemia/epidemiologia , Injúria Renal Aguda/sangue , Injúria Renal Aguda/fisiopatologia , Fatores Etários , Doenças Cardiovasculares/sangue , Doenças Cardiovasculares/fisiopatologia , Comorbidade , Feminino , Humanos , Hipertensão/sangue , Hipertensão/fisiopatologia , Hiperuricemia/sangue , Hiperuricemia/fisiopatologia , Masculino , Prevalência , Prognóstico , Ensaios Clínicos Controlados Aleatórios como Assunto , Medição de Risco , Índice de Gravidade de Doença , Fatores Sexuais , Análise de Sobrevida , Estados UnidosRESUMO
INTRODUCTION: Host lipid metabolism influences viral replication and lifecycle of hepatitis C virus. Our aim was to evaluate changes in glucose and lipid metabolism of patients with chronic hepatitis C after therapy with direct acting antivirals (DAA). MATERIAL AND METHODS: We considered patients consecutively treated between January and November 2015 recording clinical data at baseline and week 24 of follow-up. Frozen serum samples were used for apolipoprotein A1 (apoA1), apolipoprotein B (apoB) and lipoprotein (a) [Lp(a)]. Wilcoxon test was utilized to estimate trends and Logistic Regression for predictors of lipid changes. RESULTS: We enrolled 100 patients, mostly cirrhotic (81%) and with genotype 1b (59%). Ninety-three patients achieved sustained virological response (SVR), while 7 relapsed. Homeostasis model assessment of insulin resistance declined (from 3 to 2.7, p < 0.001); non-high density lipoprotein (HDL) cholesterol increased from 102 ± 29 to 116 ± 35 (p < 0.001), and Lp(a) from 5.6 ± 6.5 to 9.8 ± 11.5 mg/dL (p < 0.001). Rise of low-density lipoprotein/HDL and apoB/apoA1 ratio were registered (from 1.79 ± 1.10 to 2.08 ± 1.05 and from 0.48 ± 0.18 to 0.53 ± 0.18 mg/dL, p < 0.001). We conducted a subanalysis on patients with relapse. In this subgroup, no change of lipid profile was recorded. At multivariate analysis emerged that the addition of ribavirin to DAA, represented an independent predictor of increased Lp(a) (OR 3.982, 95% CI 1.206-13.144, p = 0.023). CONCLUSION: DAA therapy led to reduction of insulin resistance. In contrast, pro-atherogenic lipid changes were observed in patients with SVR. Further studies will be necessary to evaluate the cardiovascular balance between amelioration of glucose metabolism and negative changes of lipid profile.