LDL oxidada: Como um fator de risco para doença cardiovascular no transplante renal / Oxidized LDL: As a risk factor for cardiovascular disease in renal transplantation

RESUMO Objetivos: A taxa de mortalidade de pacientes com doença renal crônica (DRC), que tenham sido submetidos à terapia de substituição renal, é muito elevada devido a doenças cardiovasculares (DCV). Alguns estudos indicaram que a ciclosporina A (CsA), um medicamento utilizado para prevenir a rejeição de transplante, está associada à perda óssea após o transplante. Além disso, ela tem um efeito oxidante sobre os lipídeos circulantes. Seu efeito pró-oxidante nas membranas celulares provoca a liberação de cálcio. Este estudo teve como objetivo analisar se o transplante renal pode ou não resultar em melhora no estresse oxidativo (EO); e avaliar a associação entre a LDL oxidada (LDL-ox) e algumas variáveis na predição do risco de DCV em pacientes transplantados renais (TR), comparados com o grupo controle. Materiais e Métodos: Um total de 30 pacientes com DRC foram recrutados para avaliação das alterações dependentes do tempo no biomarcador de EO antes e após TR. Foram avaliados: LDL-ox, parâmetros do metabolismo dos lipídeos, a CsA, creatinina, cálcio e fosfato tanto antes do TR, 10 dias e 6 meses após o TR, em comparação com o grupo controle (n = 30). Resultados: após 6 meses, a concentração de LDL-ox mudou de 79,7 ± 9,7-72 ± 7 mU/ml (p < 0,009). O nível de fosfato de cálcio foi positivamente correlacionado com a concentração de LDL-ox (R = 0,467, p = 0,011) e ciclosporina (r = 0,419, p = 0,024) 6 meses após o transplante. Conclusão: Os resultados indicaram que a restauração da função renal pelo transplante, melhora o estresse oxidativo induzido pela uremia. O produto de fosfato de cálcio, como um fator de risco independente para DCV, correlaciona-se com o LDL-ox antes do TR e 6 meses após o TR. O produto de fosfato de cálcio também se correlaciona com a ciclosporina no grupo TR.

ABSTRACT Objectives: The mortality rate of chronic kidney disease (CKD) patients that have undergone renal replacement therapy is very high due to cardiovascular diseases (CVD). Some studies have indicated that cyclosporine A, a drug used to prevent transplant rejection, is associated with bone loss following transplantation. Furthermore, it has an oxidative effect on circulating lipids. Its prooxidant effect on cell membranes causes calcium release. This study aimed to examine whether or not renal transplantation result in improvement in oxidative stress and to assess the association between oxidized LDL (ox-LDL) and some variables in the prediction of CVD risk in Renal Transplantation (RT) patients that were compared with the control group. Material and Methods: A total number of 30 CKD patients were recruited to evaluate time dependent changes in biomarker of OS before and after RT. The ox-LDL, lipid metabolism parameters, CsA, creatinine, calcium and phosphate were assessed both before RT, 10 days and 6 months after RT in comparison with the control group (n = 30). Results: Over 6 months, ox-LDL concentration changed from 79.7 ± 9.7 to 72 ± 7 mU/mL (p < 0.009). calcium phosphate level was positively correlated with the concentration of ox-LDL (R = 0.467, p = 0.011) and cyclosporine (R = 0.419, p = 0.024) 6 months after transplantation. Conclusion: The findings indicated that restoring renal function by transplantation, improves uremia induced oxidative stress. calcium phosphate product, as an independent risk factor for CVD, correlates with ox-LDL before RT and 6 months after RT. Calcium phosphate product correlates with cyclosporine in the RT group, too.

The effect of red grape seed extract on serum paraoxonase activity in patients with mild to moderate hyperlipidemia / O efeito do extrato de semente de uva vermelha na atividade do soro paraoxonase em doentes com hiperlipidemia leve a moderada

ABSTRACT: CONTEXT AND OBJECTIVE: Red grape seed extract (RGSE) contains oligomeric proanthocyanidin complexes as a class of flavonoids. These compounds are potent antioxidants and exert many health-promoting effects. This study aimed to determine the effects of RGSE on serum levels of triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), apolipoprotein AI (apo-AI) levels and paraoxonase (PON) activity in patients with mild to moderate hyperlipidemia (MMH). DESIGN AND SETTINGS: A randomized double-blind placebo-controlled clinical trial was conducted at Shahid-Modarres Hospital (Tehran, Iran) and Tabriz University of Medical Sciences. Seventy MMH patients were randomly assigned to receive treatment (200 mg/day of RGSE) or placebo for eight weeks. RESULTS: Significant elevation in serum levels of apo-AI (P = 0.001), HDL-C (P = 0.001) and PON activity (P = 0.001) and marked decreases in concentrations of TC (P = 0.015), TG (P = 0.011) and LDL-C (P = 0.014) were found in the cases. PON activity was significantly correlated with apo-AI (r = 0.270; P < 0.01) and HDL-C (r = 0.45; P < 0.001). Significant differences between the RGSE and control groups (before and after treatment) for TC (P = 0.001), TG (P = 0.001), PON (P = 0.03), apo-AI (P = 0.001) and LDL-C (P = 0.002) were seen. CONCLUSION: It is possible that RGSE increases PON activity mostly through increasing HDL-C and apo-AI levels in MMH patients. It may thus have potential beneficial effects in preventing oxidative stress and atherosclerosis in these patients.

RESUMO: CONTEXTO E OBJETIVO: Extrato de semente de uva vermelha (RGSE) contém complexos de proantocianidinas oligoméricas como classe de flavonoides. Estes compostos são antioxidantes potentes e exercem muitos efeitos de promoção da saúde. Este estudo visou determinar os efeitos de RGSE nos níveis séricos de triglicérides (TG), colesterol total (TC), colesterol de lipoproteína alta-densidade (HDL-C), colesterol de lipoproteína baixa-densidade (LDL-C), apolipoproteína AI (apo-AI) e atividade de paraoxonase (PON) em pacientes com hiperlipidemia leve a moderada (MMH). DESENHO E LOCAL: Estudo clínico randomizado duplo-cego controlado com placebo, realizado no Hospital Shahid-Modarres (Teerã, Irã) e na Universidade de Ciências Médicas de Tabriz. Setenta pacientes com MMH foram aleatoriamente designados para receber tratamento (200 mg/dia de RGSE) ou placebo durante oito semanas. RESULTADOS: Elevação significativa nos níveis séricos de apo-AI (P = 0,001), HDL-C (P = 0,001) e atividade de PON (P = 0,001) e diminuição marcada nas concentrações de TC (P = 0,015), TG (P = 0,011) e LDL-C (P = 0,014) foram encontradas nos casos. Atividade de PON mostrou correlação significativa com apo-AI (r = 0,270; P < 0,01) e HDL-C (r = 0,45; P < 0,001). Diferenças significativas entre os grupos RGSE e controle (antes e após tratamento) para TC (P = 0,001), TG (P = 0,001), PON (P = 0,03), apo-AI (P = 0,001) e LDL-C (P = 0,002) foram observadas. CONCLUSÃO: É possível que RGSE aumente atividade de PON principalmente através da elevação dos níveis de HDL-C e apo-AI em pacientes MMH. Ele pode, assim, ter efeitos benéficos potenciais na prevenção de estresse oxidativo e aterosclerose nesses pacientes.

Protective Effect of Fish Oil Supplementation on DNA Damage Induced by Cigarette Smoking.

The study examined the influence of fish oil (FO) supplementation on serum 8-hydroxy-2’-deoxyguanosine (8-OHdG) levels as indicated by DNA damage markers and total antioxidant capacity (TAC) among male cigarette smokers. This double-blind, placebo-controlled randomized study was conducted among healthy cigarette smokers (n=40) who were part of a larger prospective cohort study. Twenty smokers were randomly selected to receive FO for 3 months (1 g/day), and another 20 smokers received a placebo for 3 months; 8-OHdG and TAC levels were measured in blood samples before and after the intervention. Serum 8-OHdG significantly decreased (p=0.001) and TAC increased (p<0.001) after 3 months of treatment with FO. Between baseline and endline, the difference in 8-OHdG significantly correlated with the difference in TAC among smokers who received FO (r=-0.540, p=0.014). The study provides evidence that FO supplementation can modify decreased antioxidants and increased oxidative DNA damage in cigarette smokers.

Preventive effect of onion juice on selenite-induced experimental cataract.

Purpose: To evaluate the effects of onion juice on sodium-selenite induced cataract formation. Materials and Methods: Thirty-two 10-day-old Wistar-albino rat pups were divided into four equal groups. Group 1 received only subcutaneous saline injection. In Group 2, sodium-selenite (30 nmol / g body weight) was injected subcutaneously. In Group 3, subcutaneous sodium-selenite was injected and one drop 50% diluted fresh juice of crude onion was instilled every 8 h into the right eye for 14 days; the left eye received no treatment. Group 4 rats were similar to those of Group 3, the only difference being that of undiluted fresh juice of crude onion. The development of cataract was assessed. Rat lenses were analyzed for total antioxidant (TA) level, and for activities of glutathione peroxidase (GPX) and superoxide dismutase (SOD). Results: Both eyes of all rats in Group 1 did not exhibit cataract formation . In Group 2, all rats developed Grade 3 cataract in the lenses of both eyes. The difference in exhibited cataract in the lens of the right eyes in all rats between Group 2 and any eyes of groups 3 or 4 were significant ( P = 0.001). The mean TA level and mean activities of SOD and GPX in Group 2 rat lenses were significantly lower than the values in lenses of all rats in Group 1 ( P = 0.001, 0.003, 0.001), and in the lenses of the right eyes of rats in Groups 3 and 4 ( P = 0.001, 0.020, 0.001). Conclusion: Instillation of onion juice into the rat eyes can effectively prevent selenite-induced cataract formation. This effect was associated with increased TA level, SOD and GPX activities in the lens.

Comparison study on the effect of prenatal administration of high dose and low dose folic acid

To evaluate the effect of high dose and low dose folic acid on the levels of hemocysteine Hcy concentration during the first trimester of pregnancy and at delivery, and to examine the association of Hcy serum levels and preeclampsia. In a single blinded randomized clinical trial, which was conducted in Tabriz, Iran, from 2005-2008, 246 nulliparous pregnant women in 2 similar groups, received folic acid daily from early pregnancy until delivery 5 mg/day in group one and 0.5 mg/ day in group 2. The incidence of hypertension and laboratory changes in the levels of serum Hcy, lactate dehydrogenase, and uric acid in addition to the levels of urine creatinine and protein were compared between the groups. There was no presence of any type of hypertension in each group. The systolic blood pressures BP mm Hg at the first trimester were 114.01 +/- 8.78 for group one, 114.16 +/- 9.05 for group 2, and at delivery, 117.24 +/- 6.91 for group one, and 117.23 +/- 11.48 for group 2 p = 0.32. The diastolic BP at the first trimester were 74.90 +/- 7.45 for group one, 73.30 +/- 8.90 for group 2, and at delivery 76.46 +/- 5.58 for group one, and 76.69 +/- 8.62 for group 2 p = 0.42. Although the level of Hcy umol/L decreased significantly at the delivery time in group one 11.81 +/- 3.85 decreased to 6.44 +/- 1.88, and 2 9.08 +/- 3.24, decreased to 7.44 +/- 2.99, this decrement was more significant in the first group p < 0.001. The results show that folic acid supplement throughout pregnancy, irrespective of the dosage, could eliminate hypertensive disorders, and decreases serum level of Hcy, although it is reduced more significant in the first group