Effect of aging, caloric restriction, and uncoupling protein 3 (UCP3) on mitochondrial proton leak in mice

Mitochondrial proton leak may modulate reactive oxygen species (ROS) production and play a role in aging. The purpose of this study was to determine proton leak across the life span in skeletal mitochondria from calorie-restricted and UCP2/3 overexpressing mice. Proton leak in isolated mitochondria and markers of oxidative stress in whole tissue were measured in female C57BL/6J mice fed ad-libitum (WT-Control) or a 30% calorie-restricted (WT-CR) diet, and in mice overexpressing UCP2 and UCP3 (Positive-TG), their non-overexpressing littermates (Negative-TG) and UCP3 knockout mice (UCP3KO). Proton leak in WT-CR mice was lower than that of control mice at 8 and 26 months of age. The Positive-TG mice had greater proton leak than the Negative-TG and UCP3KO mice at 8 months of age, but this difference disappeared by 19 and 26 months. Lipid peroxidation was generally lower in WT-CR vs. WT-Control mice and UCP3KO mice had greater concentrations of T-BARS (thiobarbituric acid reactive substances, a measure of lipid peroxidation) than did Positive-TG and Negative-TG. The results of this study indicate that sustained increases in muscle mitochondrial proton leak are not responsible for alterations in life span with calorie restriction or UCP3 overexpression in mice. However, UCP3 may contribute to the actions of CR through mechanisms distinct from increasing basal proton leak.     

氧化应激相关线粒体功能障碍与支气管哮喘

支气管哮喘(简称哮喘)是一种以不同程度的气流阻塞、气道高反应性和气道炎症为特点的复杂的炎症性疾病,受到遗传和环境因素的共同影响.分子生物学、细胞学以及动物模型研究提示线粒体功能障碍和氧化应激在哮喘发病中起着重要作用.哮喘状态下,炎症细胞内活性氧自由基生成增加,线粒体功能出现障碍,同时伴随气道上皮细胞损伤,并影响气道平滑肌功能.过敏性哮喘小鼠模型研究以及利用哮喘患者的外周细胞和组织进行的研究提示,抗氧化治疗有望成为哮喘预防与治疗的有效方法.本文将主要对以下方面进行讨论:①健康状态下的线粒体结构与功能;②氧化应激与线粒体功能障碍;③肺部氧化应激的来源及中和机制;④哮喘状态下的氧化应激和线粒体功能障碍;⑤线粒体靶向抗氧化剂的研究进展.     

Influence of aerobic fitness on age-related lymphocyte DNA damage in humans: relationship with mitochondria respiratory chain and hydrogen peroxide production

The aim of this study was to analyze the influence of aerobic fitness (AF) on age-related lymphocyte DNA damage in humans, giving special attention to the role of the mitochondrial respiratory chain and hydrogen peroxide production. Considering age and AF (as assessed by VO₂max), 66 males (19–59 years old) were classified as high fitness (HF) or low fitness (LF) and distributed into one of the following groups: young adults (19–29 years old), adults (30–39 years old), and middle-aged adults (over 40 years old). Peripheral lymphocytes obtained at rest were used to assess DNA damage (strand breaks and formamidopyrimidine DNA glycosylase (FPG) sites through the comet assay), activity of mitochondrial complexes I and II (polarographically measured), and the hydrogen peroxide production rate (assayed by fluorescence). Results revealed a significant interaction between age groups and AF for DNA strand breaks (F = 8.415, p = .000), FPG sites (F = 11.766, p = .000), mitochondrial complex I activity (F = 7.555, p = .000), and H₂O₂ production (F = 7.500, p = .000). Except for mitochondrial complex II activity, the age variation of the remaining parameters was significantly attenuated by HF. Considering each AF level, an increase in DNA strand breaks and FPG sites with age (r = 0.655, p = 0.000, and r = 0.738, p = 0.000, respectively) was only observed in LF. Moreover, decreased mitochondrial complex I activity with age (r = −.470, p = .009) was reported in LF. These results allow the conclusion that high AF seems to play a key role in attenuating the biological aging process.     

Oxidative stress and severe walking disability among older women

Background

Oxidative stress has been implicated in sarcopenia and the loss of muscle strength with aging, but the relationship between oxidative stress and decrease in muscle strength and physical performance has not been well characterized. Serum protein carbonyls are markers of oxidative damage to proteins and are caused by oxidative stress.

Methods

Serum protein carbonyls were measured at baseline and compared with a decrease in walking speed and development of severe walking disability (inability to walk or walking speed <0.4 m/sec) over 36 months of follow-up in 545 moderately to severely disabled women, aged ≥65 years, living in the community in Baltimore, Maryland (the Women’s Health and Aging Study I).

Results

After adjusting for age, body mass index, smoking, and chronic diseases, log_e protein carbonyls (nmol/mg) were associated with a decrease in walking speed over 36 months (P = .002). During follow-up, 154 women (28.2%) developed severe walking disability. After adjusting for the same potential confounders, log_e protein carbonyls were associated with incident severe walking disability (hazards ratio 1.42, 95% confidence interval, 1.02-1.98, P = .037).

Conclusion

High oxidative stress, as indicated by oxidative damage to proteins, is an independent predictor of decrease in walking speed and progression to severe walking disability among older women living in the community.     

Oxidative stress,cardiolipin and mitochondrial dysfunction in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease(NAFLD) is today considered the most common form of chronic liver disease, affecting a high proportion of the population worldwide. NAFLD encompasses a large spectrum of liver damage, ranging from simple steatosis to steatohepatitis, advanced fibrosis and cirrhosis. Obesity, hyperglycemia, type 2 diabetes and hypertriglyceridemia are the most important risk factors. The pathogenesis of NAFLD and its progression to fibrosis and chronic liver disease is still unknown. Accumulating evidence indicates that mitochondrial dysfunction plays a key role in the physiopathology of NAFLD, although the mechanisms underlying this dysfunction are still unclear. Oxidative stress is considered an important factor in producing lethal hepatocyte injury associated with NAFLD. Mitochondrial respiratory chain is the main subcellular source of reactive oxygen species(ROS), which may damage mitochondrial proteins, lipids and mitochondrial DNA. Cardiolipin, a phospholipid located at the level of the inner mitochondrial membrane, plays an important role in several reactions and processes involved in mitochondrial bioenergetics as well as in mitochondrial dependent steps of apoptosis. This phospholipid is particularly susceptible to ROS attack. Cardiolipin peroxidation has been associated with mitochondrial dysfunction in multiple tissues in several physiopathological conditions, including NAFLD. In this review, we focus on the potential roles played by oxidative stress and cardiolipin alterations in mitochondrial dysfunction associated with NAFLD.     

Oxidative stress in testis of animals during aging with and without reproductive activity

The free radical theory of aging postulates that an imbalance between reactive oxygen species (ROS) and reactive nitrogen species (RNS) and antioxidant defenses is important in senescence. To address this issue and gain insight into the aging process, we have evaluated the antioxidant defenses and have assessed oxidative damage in testis tissues in aging male rats. In order to relate aging and reproduction, animals with and without reproductive activity were studied. In reproductive animals the results showed a progressive increase in antioxidant enzyme activity until 12 months of age followed by an abrupt fall at 24 months. In non-reproductive animals, antioxidant activity was stable through 12 months of age, but again, fell abruptly at 24 months of age. In addition, increased aconitase activity and increased testosterone levels were found among reproductively active animals. The data demonstrate the existence of metabolic differences in testis of reproductively experienced animals and reproductively naïve animals.     

Oxidative stress in alcohol-related liver disease

Alcohol consumption is one of the leading causes of the global burden of disease and results in high healthcare and economic costs. Heavy alcohol misuse leads to alcohol-related liver disease, which is responsible for a significant proportion of alcohol-attributable deaths globally. Other than reducing alcohol consumption, there are currently no effective treatments for alcohol-related liver disease. Oxidative stress refers to an imbalance in the production and elimination of reactive oxygen species and antioxidants. It plays important roles in several aspects of alcohol-related liver disease pathogenesis. Here, we review how chronic alcohol use results in oxidative stress through increased metabolism via the cytochrome P4502E1 system producing reactive oxygen species, acetaldehyde and protein and DNA adducts. These trigger inflammatory signaling pathways within the liver leading to expression of pro-inflammatory mediators causing hepatocyte apoptosis and necrosis. Reactive oxygen species exposure also results in mitochondrial stress within hepatocytes causing structural and functional dysregulation of mitochondria and upregulating apoptotic signaling. There is also evidence that oxidative stress as well as the direct effect of alcohol influences epigenetic regulation. Increased global histone methylation and acetylation and specific histone acetylation inhibits antioxidant responses and promotes expression of key pro-inflammatory genes. This review highlights aspects of the role of oxidative stress in disease pathogenesis that warrant further study including mitochondrial stress and epigenetic regulation. Improved understanding of these processes may identify novel targets for therapy.     

Oxidative stress, sperm survival and fertility control

The human spermatozoon is highly susceptible to oxidative stress. This process induces peroxidative damage in the sperm plasma membrane and DNA fragmentation in both the nuclear and mitochondrial genomes. Such stress may arise from a variety of sources including a lack of antioxidant protection, the presence of redox cycling xenobiotics, infiltrating leukocytes and excess reactive oxygen species production by the spermatozoa. Whenever the levels of oxidative stress in the male germ line are high, the peroxidation of unsaturated fatty acids in the sperm plasma membrane ensures that normal fertilization cannot occur. However, at lower levels of oxidative stress, spermatozoa may retain their capacity for fertilization while carrying significant levels of oxidative damage in their DNA. Epidemiological evidence suggests that subsequent aberrant repair of such damage in the zygote may result in the creation of mutations associated with pre-term pregnancy loss and a variety of pathologies in the offspring, including childhood cancer. Thus, while the induction of oxidative stress in spermatozoa is causally involved in the aetiology of male infertility, the prospects of using such a strategy for male contraception is fraught with potential problems, should the suppression of fertility be incomplete and DNA-damaged spermatozoa gain access to the oocyte.     

Telomerase,mitochondria and oxidative stress

Telomerase plays an important role in cellular proliferation capacity and survival under conditions of stress. A large part of this protective function is due to telomere capping and maintenance. Thus it contributes to cellular immortality in stem cells and cancer. Recently, evidence has accumulated that telomerase can contribute to cell survival and stress resistance in a largely telomere-independent manner. Telomerase has been shown to shuttle dynamically between different cellular locations. Under increased oxidative stress telomerase is excluded from the nucleus and can be found within the mitochondria. This phenotype correlates with decreased oxidative stress within telomerase expressing cells and improved mitochondrial function by currently largely unknown mechanisms. Our data suggest that mitochondrial protection could be an important non-canonical function for telomerase in cell survival and ageing. This review summarises briefly our knowledge about extra-telomeric functions of telomerase and discusses the potential significance of its mitochondrial localisation.     

Oxidative stress induces gastric submucosal arteriolar dysfunction in the elderly

AIM:To evaluate human gastric submucosal vascular dysfunction and its mechanism during the aging process.METHODS:Twenty male patients undergoing subtotal gastrectomy were enrolled in this study.Young and elderly patient groups aged 25-40 years and 60-85 years,respectively,were included.Inclusion criteria were:no clinical evidence of cardiovascular,renal or diabetic diseases.Conventional clinical examinations were carried out.After surgery,gastric submucosal arteries were immediately dissected free of fat and connective tissue.Vascular responses to acetylcholine(ACh)and sodium nitroprusside(SNP)were measured by isolated vascular perfusion.Morphological changes in the gastric mucosal vessels were observed by hematoxylin and eosin(HE)staining and Verhoeff van Gieson(EVG)staining.The expression of xanthine oxidase(XO)and manganese-superoxide dismutase(Mn-SOD)was assessed by Western blotting analysis.The malondialdehyde(MDA)and hydrogen peroxide(H2O2)content and the activities of superoxide dismutase(SOD)and glutathione peroxidase(GSH-Px)were determined according to commercial kits.RESULTS:The overall structure of vessel walls was shown by HE and EVG staining,respectively.Disruption of the internal elastic lamina or neointimal layers was not observed in vessels from young or elderly patients;however,cell layer number in the vessel wall increased significantly in the elderly group.Compared with submucosal arteries in young patients,the amount of vascular collagen fibers,lumen diameter and media cross-sectional area were significantly increased in elderly patients.Ach-and SNP-induced vasodilatation in elderly arterioles was significantly decreased compared with that of gastric submucosal arterioles from young patients.Compared with the young group,the expression of XO and the contents of MDA and H2O2in gastric submucosal arterioles were increased in the elderly group.In addition,the expression of Mn-SOD and the activities of SOD and GSH-Px in the elderly group decreased significantly compared with those in the young gr     

氧化应激与Graves眼病

Graves眼病(GO)患者血清活性氧簇(ROS)水平明显增高;后者刺激患者眼眶成纤维细胞(OF)分化,促进氨基葡聚糖(GAG)的生成,诱导人白细胞抗原-DR(HLA-DR)和热休克蛋白-72、细胞间黏附分子-1(ICAM-1)的表达,促进GO的发生、发展.吸烟作为最重要的环境因素,主要通过促进ROS的增加和抗氧化物质的减少,加剧GO的发展.因此,抗氧化剂可通过清除氧自由基抑制ROS所诱导的一系列反应.可见,氧化应激在GO发病机制中发挥重要作用.     

Oxidative stress in hypertensive,diabetic, and diabetic hypertensive rats

BACKGROUND: Reactive oxygen species play a key role in the formation of endothelial dysfunction accompanying diabetes mellitus, hypertension, and other cardiovascular diseases. METHOD: This study compares oxidative stress (OS) in Wistar-Kyoto rats (WKY), spontaneously hypertensive rats (SHR), non-insulin-dependent Cohen Diabetic rats (CDR), and Cohen Rosenthal diabetic hypertensive rats (CRDH), a unique animal model of both diabetes and hypertension. The OS was evaluated with a newly developed thermochemiluminiscence (TCL) analyzer (Lumitest Ltd., Nesher, Israel) that measures the oxidizability (ie, susceptibility to oxidation) of a test sample. RESULTS: The TCL oxidizability test results of sera from the different rats groups showed a time-dependent increase in TCL of up to 145% +/- 7% for WKY, 160% +/- 8% for SHR, 179% +/- 12% for CDR, and 226% +/- 15% for CRDH. These results were significant: P <.001 for SHR and CDR and P <.0001 for CRDH in comparison to WKY. Lipid peroxide levels also increased in each strain of rats: to 80 +/- 7.8 nmol/mL in WKY, 104 +/- 10.1 nmol/mL in SHR, 110 +/- 9.4 nmol/mL in CDR, and 167 +/- 11.7 nmol/mL in CRDH. These results were also significant: P <.001 for SHR, CDR and CRDH in comparison to WKY. CONCLUSION: The combination of hypertension and diabetes is accompanied by higher oxidative stress than that seen with either disorder alone.     

一种新发现的线粒体DNA大片段缺失与衰老的关系初探

目的 在人外周血细胞中筛选新的线粒体DNA（mtDNA）大片段缺失突变,探讨mtDNA尤其在片段缺失突变与衰老的关系。方法 以人外周血细胞DNA为模板,进行聚合酶链反应（PCR）扩增,产物克隆、测序。用PCR半定量方法测定1条长达13．1kb的mtDNA缺失突变,＜60岁组和≥60岁组突变型与野生型的比例,差异有显著性。结论 该突变以前未见报道,可能是一种与衰老有关的缺失突变。     

氧化应激与糖尿病神经病变

氧化应激与糖尿病神经病变的发生、发展密切相关,晚期糖基化终末产物、多元醇通路和蛋白激酶C激活等途径均可增加体内氧化应激反应导致糖尿病神经病变的发生、发展。应用α-硫辛酸,维生素C、E和褪黑素等抗氧化治疗将为糖尿病神经病变的防治提供新的思路。     

帕金森病的线粒体功能障碍与氧化应激

帕金森病(PD)是一种中老年人神经系统变性疾病,其病因和发病机制至今仍未明确,大量研究表明线粒体功能障碍、氧化应激、细胞凋亡、兴奋性氨基酸毒性、炎症反应都参与了帕金森病的发病过程.线粒体功能障碍与氧化应激一直是研究的热点,现主要就帕金森病的线粒体功能障碍与氧化应激做一综述.     

氧化应激与肝脏保护

活性氧自由基引发的氧化应激是多种肝病发病的共同病理生理基础,在各种慢性肝病的形成和发展过程中起重要作用。本文主要阐述氧化应激与肝脏保护的关系,并根据两者关系阐述了目前保肝抗氧化物质的抗氧化作用机制。     

Oxidative stress participates in age-related changes in rat lumbar intervertebral discs

Aging is a major factor associated with lumber intervertebral disc degeneration, and oxidative stress is known to play an essential role in the pathogenesis of many age-related diseases. In this study, we investigated oxidative stress in intervertebral discs of Wistar rats in three different age groups: youth, adult, and geriatric. Age-related intervertebral disc changes were examined by histological analysis. In addition, oxidative stress was evaluated by assessing nitric oxide (NO), superoxide dismutase (SOD), malondialdehyde (MDA), and advanced oxidation protein products (AOPPs). Intervertebral disc, but not serum, NO concentrations significantly differed between the three groups. Serum and intervertebral disc SOD activity gradually decreased with age. Furthermore, both serum and intervertebral disc MDA and AOPP levels gradually increased with age. Our studies suggest that oxidative stress is associated with age-related intervertebral disc changes.     

Evaluation of sex differences on mitochondrial bioenergetics and apoptosis in mice

It has been postulated that the differences in longevity observed between organisms of different sexes within a species can be attributed to differences in oxidative stress. It is generally accepted that differences are due to the higher female estrogen levels. However, in some species males live the same or longer despite their lower estrogen values. Therefore, in the present study, we analyze key parameters of mitochondrial bioenergetics, oxidative stress and apoptosis in the B6 (C57Bl/6J) mouse strain. There are no differences in longevity between males and females in this mouse strain, although estrogen levels are higher in females. We did not find any differences in heart, skeletal muscle and liver mitochondrial oxygen consumption (State 3 and State 4) and ATP content between male and female mice. Moreover, mitochondrial H(2)O(2) generation and oxidative stress levels determined by cytosolic protein carbonyls and concentration of 8-hydroxy-2'-deoxyguanosine in mitochondrial DNA were similar in both sexes. In addition, markers of apoptosis (caspase-3, caspase-9 and mono- and oligonucleosomes: the apoptosis index) were not different between male and female mice. These data show that there are no differences in mitochondrial bioenergetics, oxidative stress and apoptosis due to gender in this mouse strain according with the lack of differences in longevity. These results support the Mitochondrial Free Radical Theory of Aging, and indicate that oxidative stress generation independent of estrogen levels determines aging rate.     

支气管哮喘中氧化应激与抗氧化状态

氧化应激被认为在支气管哮喘（哮喘）的气道慢性炎症中起着重要作用。本文阐述了氧化应激对机体的损伤作用，评估了哮喘患者体内氧化应激状态，以及糖皮质激素、饮食、抗氧化治疗等因素对哮喘患者氧化应激状态的影响。     

氧化应激与支气管哮喘气道黏液高分泌研究进展

哮喘是一种以支气管收缩可逆性、肺部炎症及气道重塑为特点的慢性气道炎症性疾病.黏液过度分泌导致气道阻塞、肺功能下降、气道重塑和感染增加.过度的活性氧/活性氮(ROS/RNS)产生造成气道炎症,气道高反应性,气道微血管高通透性和气道黏液高分泌,以及组织损伤和形态的改变.减轻氧化应激或增加抗氧化能够减轻气道嗜酸粒细胞,减少黏液分泌,减轻支气管高反应性.本文就氧化应激与哮喘气道黏液高分泌的关系作一综述.