RESUMO
Introduction: Homocysteine (Hcy) tissue accumulation occurs in a metabolic disease characterized biochemically by cystathionine ß-synthase (CBS) deficiency and clinically by mental retardation, vascular problems, and skeletal abnormalities. Previous studies indicate the occurrence of DNA damage secondary to hyperhomocysteinemia and it was observed that DNA damage occurs in leukocytes from CBS-deficient patients. This study aimed to investigate whether an oxidative mechanism could be involved in DNA damage previously found and investigated the in vitro effect of N-acety-L-cysteine (NAC) on DNA damage caused by high Hcy levels. Methods: We evaluated a biomarker of oxidative DNA damage in the urine of CBSdeficient patients, as well as the in vitro effect of NAC on DNA damage caused by high levels of Hcy. Moreover, a biomarker of lipid oxidative damage was also measured in urine of CBS deficient patients. Results: There was an increase in parameters of DNA (8-oxo-7,8-dihydro-2'- deoxyguanosine) and lipid (15-F2t-isoprostanes levels) oxidative damage in CBS-deficient patients when compared to controls. In addition, a significant positive correlation was found between 15-F2t-isoprostanes levels and total Hcy concentrations. Besides, an in vitro protective effect of NAC at concentrations of 1 and 5 mM was observed on DNA damage caused by Hcy 50 µM and 200 µM. Additionally, we showed a decrease in sulfhydryl content in plasma from CBS-deficient patients when compared to controls. Discussion: These results demonstrated that DNA damage occurs by an oxidative mechanism in CBS deficiency together with lipid oxidative damage, highlighting the NAC beneficial action upon DNA oxidative process, contributing with a new treatment perspective of the patients affected by classic homocystinuria.
Assuntos
Humanos , Feminino , Criança , Adolescente , Adulto , Adulto Jovem , Acetilcisteína/farmacologia , Dano ao DNA , Estresse Oxidativo , Cistationina/metabolismo , Desoxiguanosina/urina , Homocistinúria/genética , Antioxidantes/farmacologia , Biomarcadores/urina , Estudos de Casos e Controles , Creatinina/urina , Ensaio Cometa , Cistationina/biossíntese , Cistationina/sangue , Isoprostanos/análise , Desoxiguanosina/análogos & derivados , Homocisteína/sangue , Homocistinúria/sangueRESUMO
Introducción: La vía intracellular de RhoA/Rho kinasa es activada por agonistas de receptores acoplados a proteínas G pequeñas unidas a membrana. Su activación está relacionada al remodelado cardiovascular patológico. Previamente hemos observado aumento de actividad de Rho kinasa (ROCK) en pacientes con hipertensión arterial (HT) e hipertrofia ventricular izquierda como daño de órgano blanco. Pero su activación en relación a la diabetes no ha sido explorada en estos pacientes. Objetivo: Evaluar activación de Rho kinasa y parámetros de estrés oxidativo en pacientes hipertensos con diabetes tipo II (DMII). Métodos: Estudio comparativo entre pacientes con HT sin tratamiento, HT con DMII y hemoglobina glicosi-lada Alc > 7,5 por ciento y un grupo control normotenso. Se realizó ecocardiograma de superficie. Se midió activación de ROCK en leucocitos circulantes midiendo MYPT1 fosforilado/total (p/t) por Western blot y la velocidad de pulso carotídeo-femoral (PWV) para estimar distensibilidad arterial. El stress oxidativo se estimó midiendo ma-londialdehído (MDA) y 8-isoprostano (8-ISO) en suero. Resultados: Se incluyeron 21 pacientes hipertensos con DMII, 38 pacientes hipertensos sin DMII y 34 controles normotensos. La edad promedio fue 51 +/- 0,9; 48 +/- 0,9 y 52 (p: NS) +/- 1,1 y el 47 por ciento, 50 por ciento y 52 por ciento (p: NS) eran mujeres respectivamente. Los pacientes HT con DMII presentaron MYPTl p/t (5,6 +/- 1,3; 3,6 +/- 0,4; 2,1 +/- 0,1 p< 0,01), MDA (1,8 +/- 0,4/
Background: Rho/Rho-kinase intracellular pathway is activated by membrane bound small G-proteins. Activation of Rho/Rho-kinase pathway is related to pathologic cardiac remodeling. We have previously observed this activation (ROCK) in hypertensive patients with left ventricular hypertrophy. The influence of diabetes in this relationship has not been explored. Aim: to evaluate the activation of Rho-kinase and oxi-dative stress in hypertensive patients with type II diabetes (DMII). Methods: A comparative study between patients with untreated hypertension (HT), hypertensive patients with diabetes and hemoglobin A1c > 7.5 percent and normotensi-ve control subjects was performed. LVH was assessed by echocardiography. ROCK activity was measured in peripheral leukocytes by Western blot determination of phosphorilated / total MYPT1 ratio. Arterial compliance was determined by the relationship of carotid and femoral velocity signals (PWV) Oxidative stress was estimated by serum levels of malondialdehyde (MDA) and 8-isoprostane (8-ISO). Results: Hypertensives with DMII (n=21) had a mean age of 51 +/- 0.9 years, and 47 percent were females. Corresponding figures for 38 hypertensive patients without DM and 34 control patients were 48 ± 0,9 and 52 +/- 1,1 (NS) and 50 percent and 52 percent females, respectively (NS). The MYPT1 p/t ratio was 5,6 +/- 1,3; 3,6 +/- 0,4; 2,1 +/- 0,1 (p<0.01) in the 3 groups, respectively. MDA for the 3 groups was 1,8 +/- 0,4/Assuntos
Humanos
, Masculino
, Adulto
, Feminino
, Pessoa de Meia-Idade
, /enzimologia
, Hipertensão/enzimologia
, Estresse Oxidativo
, Quinases Associadas a rho/metabolismo
, Análise de Variância
, Pressão Arterial
, Arteriosclerose
, Western Blotting
, Estudos Transversais
, Ecocardiografia
, Ativação Enzimática
, Isoprostanos/análise
, Malondialdeído/análise
, Volume Sistólico
RESUMO
We investigated whether isoprostanes, as a marker of lipid peroxidation, may be involved in the development of impaired glucose tolerance (IGT) or diabetes. Using a nested case-control study, we tracked the changes in isoprostane levels, insulin sensitivity (IS) and beta-cell function (BCF) in Afro-Jamaicans who progressed to IGT and diabetes over 3.9 years. Anthropometry, glucose tolerance, insulin levels, blood pressure and urinary isoprostane concentration were measured at baseline and follow-up. IS and BCF were estimated by the method of homeostasis assessment. Fifty-two individuals who progressed to IGT or diabetes and 44 age, sex and body mass index (BMI) matched controls were studied. Progression to glucose intolerance was significantly related with baseline BCF (p< or =0.01), but not isoprostane levels or IS. Glucose concentrations (fasting and 2 h) on follow-up were significantly correlated to baseline IS, baseline BCF, follow-up IS and follow-up BCF (p-values<0.05). In multiple regression analysis, only follow-up IS and BCF (p-values< or =0.001) independently predicted fasting glucose and 2h glucose levels at follow-up. Isoprostanes were not significantly associated with IS or BCF (p-values>0.1). We concluded that isoprostanes may not be causally involved in the development of glucose intolerance, insulin resistance or deteriorating BCF.
Assuntos
Intolerância à Glucose/etiologia , Isoprostanos/urina , Adulto , Idoso , Antropometria , Biomarcadores/urina , População Negra/etnologia , Glicemia/análise , Pressão Sanguínea , Índice de Massa Corporal , Estudos de Casos e Controles , Estudos de Coortes , Jejum , Seguimentos , Teste de Tolerância a Glucose , Humanos , Insulina/sangue , Células Secretoras de Insulina/metabolismo , Isoprostanos/análise , Jamaica/epidemiologia , Peroxidação de Lipídeos , Pessoa de Meia-Idade , Análise de Regressão , Estudos Retrospectivos , Fatores de Tempo , População Urbana/estatística & dados numéricosRESUMO
The onset of lipid peroxidation within cellular membranes is associated with changes in their physicochemical properties and with the impairment of protein functions located in the membrane environment. This article provides current information on the origin and function of polyunsaturated fatty acids in nature, lipid peroxidation of cellular membranes: enzymatic (lipoxygenases) and non-enzymatic. The latest knowledge on in vivo biomarkers of lipid peroxidation including isoprostanes, isofurans and neuroprostanes are discussed. A further focus is placed on analytical methods for studying lipid peroxidation in membranes with emphasis in chemiluminescence and its origin, rod outer segments of photoreceptors, the effect of antioxidants, fatty acid hydroperoxides and lipid protein modifications. Since rhodopsin, the major integral protein of rod outer segments is surrounded by phospholipids highly enriched in docosahexaenoic acid, the author proposes the outer segments of photoreceptors as an excellent model to study lipid peroxidation using the chemiluminescence assay since these membranes contain the highest concentration of polyunsaturated fatty acids of any vertebrate tissue and are highly susceptible to oxidative damage.