RESUMO
OBJETIVO: Avaliar o efeito da administração de uma dieta enteral industrializada com antioxidantes sobre as concentrações plasmáticas de tióis totais, carbonilas de proteínas e malondialdeído em pacientes após acidente vascular cerebral. MÉTODOS: A amostra foi constituída de 14 pacientes de um hospital geral que iniciaram nutrição enteral 48 horas após o evento. Falência múltipla, insuficiência hepática, obesidade mórbida e diabetes Mellitus associados foram critérios de exclusão. A dieta industrializada ofertada por gotejamento contínuo, com uso de bombas infusoras, continha mix de carotenoides, vitaminas C, E e minerais Se, Zn e Cu em sua formulação. As amostras de sangue foram coletadas antes do início da administração da dieta e após cinco dias de início da dieta enteral, somente de pacientes que tivessem recebido o volume necessário para completar o gasto energético total. Tióis plasmáticos e carbonilas de proteína foram determinados por meio do Reagente de Ellman e pela reação com dinitrofenilhidrazina respectivamente. O malondialdeído foi obtido pela determinação de substâncias reativas do ácido tiobarbitúrico. RESULTADOS: A média de idade foi M=70,3, DP=14,1 anos. Todos receberam acima de 100% da Dietary Reference Intakes para nutrientes antioxidantes, que não ultrapassaram os limites superiores toleráveis de ingestão. Não houve alteração da concentração de tióis, mas houve aumento da formação de carbonilas de proteínas (p=0,034). Nos pacientes entubados, esse marcador mostrou-se significativamente maior (p=0,048) após administração da dieta. Não houve diferença nas concentrações de malondialdeído após a oferta de antioxidantes dietéticos. CONCLUSÃO: A análise de biomarcadores não demonstrou redução do estresse oxidativo após administração de dieta enteral industrializada com antioxidantes.
OBJECTIVE: The aim of this study was to assess the effect of a commercial enteral diet with added antioxidants on total plasma thiol, protein carbonyl and malondialdehyde levels of stroke survivors. METHODS: Fourteen patients from a general hospital who had been started on enteral nutrition 48 hours after a stroke were included in the study. The exclusion criteria were multiple organ dysfunction syndrome, liver failure and morbid obesity associated with diabetes Mellitus. The commercial diet was fed by continuous drip via infusion pump and contained mixed carotenoids, vitamins C and E, and the minerals selenium, zinc and copper. Blood samples were collected at baseline and after 5 days of enteral diet, but only from patients whose diet intake met their total energy expenditure. Total plasma thiol and protein carbonyl levels were determined by Ellman's reagent and dinitrophenylhydrazine, respectively. Plasma malondialdehyde levels were measured by the assay of thiobarbituric acid reactive substances. RESULTS: The mean age of the sample was M=70.3 years, (SD=14.1). All patients received more than 100% of the Dietary Reference Intakes for the abovementioned antioxidants but none exceeded the tolerable upper limit. Plasma thiol and malondialdehyde levels did not vary over time but protein carbonyl levels were significantly higher (p=0.034), especially in intubated patients (p=0.048). CONCLUSION: Biomarker determinations showed that a commercial enteral diet with added antioxidants did not reduce oxidative stress.
Assuntos
Humanos , Masculino , Feminino , Idoso , Acidente Vascular Cerebral/dietoterapia , Carbonilação Proteica , Estresse Oxidativo , Nutrição EnteralRESUMO
BACKGROUND: Chronic kidney disease (CKD) is characterized by progressive kidney dysfunction accompanied by accumulation of uremic toxins and a potential disequilibrium between the redox status and the generation of prooxidants, resulting in oxidative stress and chronic inflammation which is associated with complications (particularly cardiovascular disease) in this population. We aimed to analyze the concentration of total plasma thiols (indicator of antioxidant capacity) and the protein carbonyl content (a marker of carbonyl stress) in relation to kidney function and inflammation in a group of patients with CKD. PATIENTS AND METHODS: A group of 68 patients with CKD (stages 2-5; mean age 57 ± 12 years, 46% male, 34% diabetics) and another group of 21 patients who underwent living donor kidney transplantation (mean age 36 ± 17 years, 50% male, 10% diabetics, and 9 ± 2 months after renal transplantation) were included in the study. Total plasma thiol and protein carbonyl levels were determined by the DTNB and DNPH methods, respectively, and were adjusted to the plasma albumin concentrations. Plasma levels of fibrinogen and C-reactive protein (CRP) were measured by routine methods and used as markers of inflammation. RESULTS: Mean glomerular filtration rate (GFR) was 48 ml/min, and there was a positive correlation between GFR and thiol (r = 0.25, p < 0.05) and a negative correlation between GFR and carbonyl (r = -0.26, p < 0.05), fibrinogen (r = -0.45, p < 0.0001) and CRP (r = -0.14, p = ns). Carbonyl strongly correlated with CRP (0.49, p < 0.0001) and fibrinogen (0.30, p < 0.01). There was a significant reduction in plasma carbonyl after renal transplantation (1.4 ± 0.4 nmol/mg albumin), compared with the levels before the procedure (2.0 ± 1.4 nmol/mg albumin, p < 0.05), which parallels an improvement in thiol levels (15 ± 4 vs. 21 ± 5 nmol/mg albumin, p < 0.001). In addition, there was a significant correlation between CRP and carbonyl after the transplantation (r = 0.65; p < 0.005). CONCLUSION: We observed that patients with CKD present an altered redox status and increased signs of carbonyl stress and inflammatory activity as kidney function deteriorates, which was partially but significantly improved after renal transplantation. These findings indicate the importance of renal function in the complications of CKD related to oxidative stress and inflammation.
Assuntos
Mediadores da Inflamação/sangue , Falência Renal Crônica/sangue , Falência Renal Crônica/terapia , Transplante de Rim/tendências , Estresse Oxidativo/fisiologia , Carbonilação Proteica/fisiologia , Compostos de Sulfidrila/sangue , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Estudos Transversais , Progressão da Doença , Feminino , Humanos , Falência Renal Crônica/diagnóstico , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Adulto JovemRESUMO
BACKGROUND: Kidney transplant (Tx) patients present a reduced cardiovascular (CV) mortality in comparison to the dialysis population, but in comparison to the general population, it is still several-fold higher. METHODS: We studied risk factors for CV disease in a group of 38 patients (50% males, median age 36 years) who underwent a living donor Tx at the baseline and after 3 +/- 1 and 9 +/- 2 months. RESULTS: The prevalence of overweight increased from 26 to 54% after Tx (p < 0.001). The mean systolic blood pressure decreased significantly after the Tx (148 +/- 27.6 vs. 126 +/- 12.7 mm Hg). There was a significant increase in LDL (97 +/- 30 vs. 114 +/- 35) and hematocrit (33.8 +/- 4.4 to 42 +/- 5.7%) levels and a significant reduction in fibrinogen levels (394 +/- 91 vs. 366 +/- 100 mg/dl) after 9 months as compared to the baseline. Obesity and dislipidemia were significantly correlated with inflammation. Significant changes in left ventricle mass index (293 +/- 116 vs. 241 +/- 96) were observed after the Tx. Patients with a low glomerular filtration rate (GFR) in the follow-up evaluation presented higher LDL (128 +/- 7 vs. 99 +/- 7 mg/dl; p < 0.05) and higher fibrinogen levels (399 +/- 21 vs. 332 +/- 22 mg/dl; p < 0.05) compared to patients with a high GFR. CONCLUSION: Most of the risk factors analyzed (particularly the uremia-related) improved after the renal Tx, which could justify the positive impact of Tx on the development of CV disease. Inflammation and dyslipidemia were related to renal dysfunction after the Tx, suggesting that complete restoration of renal function may have an impact on reducing CV mortality in CKD patients treated with renal Tx.