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ABSTRACT: To screen target proteins of oxidative stress which mediate the effects of exercise on preventing nonalcoholic fatty liver disease (NAFLD), the methods for selecting carbonylated proteins were modified, and carbonylated proteins were profiled. The results showed that treadmill training reduced oxidative stress and the levels of intrahepatic triglyceride (IHTG). The changes in IHTG showed a significant positive correlation with oxidative stress as indicated by malondialdehyde level. Further results from proteomics illustrated that 17 functional proteins were susceptible to oxidative modification, and exercise protected 3 proteins from carbonylation. The latter 3 proteins may serve as both direct target proteins of oxidative stress and mediators contributing to the beneficial effects of exercise. In particular, a long-chain specific acyl-CoA dehydrogenase (ACADL) which was a key enzyme in lipid metabolism was not carbonylated and with higher activities in exercise group. These findings indicate that this modified technique is practical and powerful in selecting carbonylated proteins. Long-term treadmill training is effective in ameliorating oxidative stress and preventing the accumulation of IHTG. Among the 17 target proteins of oxidative modification, 3 proteins contribute to the beneficial effects of exercise. Preventing ACADL from carbonylation may be involved in the physiological mechanism of exercise-induced NAFLD improvement.
Proteomics 03/2013; · 4.43 Impact Factor
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ABSTRACT: Oxidative stress is a key factor linked renal function decline with age. However, there is still no large cohort study exploring the potential role of oxidative stress in mild insufficiency of kidney function (MIKF) and chronic kidney disease (CKD) after adjusting for confounding factors. This study tested the hypothesis that oxidative stress, indicated by plasma malondialdehyde (MDA), is associated with the prevalence of MIKF and CKD after controlling the effects of confounding factors. Plasma levels of MDA and serum levels of fasting glucose, cholesterol, triglycerides, creatinine, alanine aminotransferase, and aspartate aminotransferase were analyzed from 2,169 Chinese Han adults. A questionnaire and physical examination were performed to identify and suspect risk factors of renal function decline with age. Kidney function, as indicated by estimated glomerular filtration rate, showed a significant decline with age in both male and female. Although the association between age and plasma MDA levels was nonlinear, MDA was negatively related to kidney function. The multivariate-adjusted odds ratios showed that plasma MDA had a significantly graded relation to the prevalence of MIKF and CKD with or without adjustment for covariates. By comparison with the lowest quartile, individuals with the highest quartile of MDA level had a 99% and 223% increased risk of developing MIKF and CKD, respectively. Further results from multiinteraction analysis demonstrated that plasma MDA may be the mediator linking different covariates with renal function decline. The most striking finding of this study was that oxidative stress, as indicated by plasma MDA levels, is associated with the prevalence of MIKF and/or CKD. Although imposing an increasing burden on the kidney and/or promoting a cyclical process of oxidative stress in the body, high levels of MDA in plasma may link the decline of kidney function with age.
Rejuvenation Research 04/2012; 15(3):257-64. · 3.83 Impact Factor
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ABSTRACT: Hematocrit is an important hemorheological parameter. Both hematocrit and nonalcoholic fatty liver disease (NAFLD) are strongly correlated with cardiovascular disease. However, there is no study to explore the direct relationship of hematocrit with NAFLD.
Hematocrit levels were analyzed from 1,821 Chinese Han adults, and questionnaire and physical examination were administered to know and suspect the relationship with NAFLD.
NAFLD morbidity was positively correlated with hematocrit levels in both male and female. Multivariate-adjusted odds ratio illustrated that, compared with the lowest quartile of hematocrit, the highest quartile subjects had a 185% and 386% increased risk for developing NAFLD in male and female, respectively. Further receiver operating characteristic analysis showed that the optimal cutoff value of hematocrit for detecting NAFLD was 42.75 in male and 37.55 in female. Unhealthy lifestyles had similar effects on NAFLD and hematocrit.
The prevalence of NAFLD is positively associated with hematocrit levels. Though the cause-effect relationship between NAFLD and hematocrit still needs further investigation to clarify, the elevated hematocrit in NAFLD patients may be of significance to link NAFLD and cardiovascular disease.
Clinical hemorheology and microcirculation 01/2012; 51(1):59-68. · 3.40 Impact Factor
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ABSTRACT: To study the role of oxidative stress in hypertension and pre-hypertension, this study analysed plasma levels of reactive carbonyl species (RCS) in 1204 Chinese Han adults. Results showed a statistically significant positive correlation (p < 0.001) between blood pressure and plasma RCS levels with or without being adjusted for covariates. Multivariate-adjusted odds ratio (OR) illustrated that, compared with the lowest quartile of plasma RCS levels, the highest quartile subjects had a 59% and a 130% increase in the risk for developing pre-hypertension and hypertension, respectively. The multi-interaction analysis manifested that the underlying mechanism of the increase of hypertensive risk or pre-hypertensive risk by overweight and unhealthy lifestyles might, at least in part, be through oxidative stress. In conclusion, these findings suggest that oxidative stress, as indicated by plasma RCS levels, are not the necessary consequence of pre-hypertension or hypertension, but reliable risk factors for developing pre-hypertension or hypertension in Chinese Han adults.
Free radical research 02/2011; 45(5):568-74. · 2.22 Impact Factor
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ABSTRACT: Oxidative stress plays a critical role in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). However, there is still no large cohort study to explore the direct risk role of oxidative stress for NAFLD. This study is to test the hypothesis that elevated oxidative stress is a direct risk factor for the pathogenesis of NAFLD under controlling the potential effects of covariates.
The levels of serum cholesterol, serum triglyceride, fasting plasma glucose and plasma reactive carbonyl species (RCS) were measured from 1204 Chinese Han adults, and the questionnaire and physical examination were administered to those with known and suspected risk factors for NAFLD.
Statistically significant high levels of blood pressure, fasting plasma glucose, serum cholesterol and triglyceride, body mass index, serum alanine aminotransferase and aspartate aminotransferase, and plasma RCS were observed in NAFLD subjects compared to healthy subjects (P < 0.01). Multivariate-adjusted odds ratio illustrated that, compared with the lowest quartile of plasma RCS levels, the highest quartile subjects had a 132% increase in the risk of developing NAFLD. Further results from multi-interaction analysis demonstrated that the underlying mechanism of the risk of NAFLD by unhealthy physical conditions and lifestyles might be, at least in part, through the oxidative stress.
Our findings provide credible evidence from a large population that oxidative stress, as indicated by plasma RCS levels, may be a direct risk factor for developing NAFLD.
Journal of Gastroenterology and Hepatology 01/2011; 26(6):1010-5. · 2.87 Impact Factor
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ABSTRACT: Reactive carbonyl species (RCS) have been widely used as indicators of oxidative stress. However, the associations of carbonyl stress with aging process and biochemical alteration of erythrocyte are still poorly understood. Fresh blood samples in vacutainer tubes containing sodium heparinate were obtained from 874 volunteers who were divided into young, adult and old groups based on their age. Plasma RCS and thiols concentrations between different age groups and erythrocyte membrane protein carbonylation in the adult group were detected within 24h of the blood sampling. Results showed that the plasma thiols concentration decreased gradually during aging process, and the p-values between all three groups are less than 0.05. The plasma RCS concentration in different age groups showed a nonlinear association with age. The levels in the young group were slightly higher than the adult group (not significant) and lower than the old group (p < 0.01). The protein carbonylation of erythrocyte membrane was positively correlated with plasma RCS concentration (p < 0.01), but not plasma thiols concentration. We conclude that higher levels of RCS, not lower levels of thiols, in plasma are a direct risk factor for the protein carbonylation of erythrocyte membrane. Owing to the decrease of thiols levels and increase of RCS levels during aging process, a shift from RCS-related redox allostasis to carbonyl stress would contribute to age-related biological dysfunction and even aging process.
Clinical hemorheology and microcirculation 01/2010; 46(4):305-11. · 3.40 Impact Factor
