Mitochondria from females exhibit higher antioxidant gene expression and lower oxidative damage than males

doi:10.1016/S0891-5849(02)01356-4

Free Radical Biology and Medicine

Volume 34, Issue 5, 1 March 2003, Pages 546-552

https://doi.org/10.1016/S0891-5849(02)01356-4 Get rights and content

Abstract

We have investigated the differential mitochondrial oxidative stress between males and females to understand the molecular mechanisms enabling females to live longer than males. Mitochondria are a major source of free radicals in cells. Those from female rats generate half the amount of peroxides than those of males. This does not occur in ovariectomized animals. Estrogen replacement therapy prevents the effect of ovariectomy. Mitochondria from females have higher levels of reduced glutathione than those from males. Those from ovariectomized rats have similar levels to males, and estrogen therapy prevents the fall in glutathione levels that occurs in ovariectomized animals. Oxidative damage to mitochondrial DNA in males is 4-fold higher than that in females. This is due to higher expression and activities of Mn-superoxide dismutase and of glutathione peroxidase in females, which behave as double transgenics overexpressing superoxide dismutase and glutathione peroxidase, conferring protection against free-radical-mediated damage in aging. Moreover, 16S rRNA expression, which decreases significantly with aging, is four times higher in mitochondria from females than in those from males of the same chronological age. The facts reported here provide molecular evidence to explain the different life span in males and females.

Introduction

Life expectancy doubled in Europe and the United States between 1900 and 1992 1, 2. In all cases life expectancy of women was higher than that of men. In Western countries in 1992, life expectancy for men was 73.7 years and for women it was 83.8 years, i.e., 9.9% higher than for men [1]. The basis of the difference in life expectancy between males and females is still unknown. This is not, however, a phenomenon specific to humans and thus attributable to social differences. In our laboratory, female Wistar rats show an average life span 16% longer than their male counterparts. The longer life span of female rats vs. males was studied in the 1960s and attributed to estrogens [3]. Estrogens have a cardioprotective effect [4], act as antioxidants in vitro [5], and have been postulated as possible protective agents against Alzheimer’s disease [6]. However, despite many studies examining the cytoprotective role of estrogens on the prevention of age-related diseases, the mechanism(s) underlying the effects of estrogens on the process of aging have not been elucidated.

Many theories have been postulated to explain aging [7]. One of the most prominent is the free radical theory of aging [8], which proposes that free radicals are involved in the cellular damage that accompanies aging and age-associated diseases [9]. A relationship between mitochondrial peroxide production and longevity of mammalian species has been reported 10, 11.

The aim of the present study was to investigate the molecular bases for the difference in life span between males and females. We found that estrogen administration has a protective effect against mitochondrial free radical production. Thus the present results may show an additional value of estrogen replacement therapy in postmenopausal women.

Section snippets

Animals

Wistar rats between 4 and 6 months of age were used. In some experiments, 4 month old OF 1 mice were used. Animals were housed at constant temperature and humidity and with a 12 h light/12 h dark cycle. They were fed on a standard laboratory diet (containing 590 g carbohydrates, 30 g lipids, and 160 g protein per kilogram of diet) and tap water ad libitum.

Ovariectomy was performed as follows: rats were anesthetized with ketamine (100 mg/kg) and acepromazine (2.5 mg/kg). Abdominal skin was cut,

Peroxide production by mitochondria from males and females

Figure 1 shows that peroxide production by hepatic mitochondria obtained from male rats is significantly (p < .01) higher than in females. This occurs using either succinate or pyruvate and malate as substrates. In both cases hepatic mitochondria from males produced 40% more peroxide than those from females. The effect is even more pronounced in brain mitochondria. Figure 1 shows that brain mitochondria in male rats produced over 80% more peroxides than in females of the same age. This change

Discussion

Mitochondria are an important source of free radicals in cells. Moreover, mitochondrial components are targets of free radical damage associated with aging 20, 23, 24, 25, 26. In view of the fact that mitochondrial oxidant production is related to longevity [11], we measured peroxide production by mitochondria from male and female rats. Figure 1 shows that mitochondria from males produce more peroxides than those from females of the same age. Moreover, synaptic mitochondria are more exposed to

Acknowledgements

This work was supported by grants from Fondo de Investigaciones Sanitarias (FIS 98/1462 and CICYT BFI-2001-2849 to J.V.) and from CICYT (PM 99/0148) to F.V.P. and SAF97-0015 to J.S.). We are grateful to Mrs. Juana Belloch and Miss Dolores Royo for their skillful technical assistance.

References (39)

H. Ku et al.
Relationship between mitochondrial superoxide and hydroperoxide production and longevity of mammalian species
Free Radic. Biol. Med
(1993)
J.C.K. Lai et al.
Preparation of synaptic and nonsynaptic mitochondria from mammalian brain
Methods Enzymol
(1979)
R. Brigelius et al.
Identification and quantitation of glutathione in hepatic protein mixed disulfides and its relationship to glutathione disulfide
Biochem. Pharmacol
(1983)
L. Flohe et al.
Superoxide dismutase assays
Methods Enzymol
(1984)
J. Miquel et al.
Mitochondrial role in cell aging
Exp. Gerontol
(1980)
J. Sastre et al.
Aging of the liverage-associated mitochondrial damage in intact hepatocytes
Hepatology
(1996)
R.P. Brandes et al.
Gender differences in the generation of superoxide anions in the rat aorta
Life Sci
(1997)
D.R. Crawford et al.
Down regulation of mammalian mitochondrial RNAs during oxidative stress
Free Radic. Biol. Med
(1997)
M. Calleja et al.
Mitochondrial DNA remains intact during Drosophila aging, but the levels of mitochondrial transcripts are significantly reduced
J. Biol. Chem
(1993)
R. Fernandez-Ballesteros et al.
Spain

J.R. Wilmoth et al.

Increase of maximum life span in Sweden, 1861–1999

Science

(2000)

S.A. Asdell et al.

The effects of sex steriod hormones upon longevity in rats

J. Reprod. Fertil

(1967)

J.F. Arnal et al.

Ethinylestradiol does not enhance the expression of nitric oxide synthase in bovine endothelial cells but increases the release of bioactive nitric oxide by inhibiting superoxide anion production

Proc. Natl. Acad. Sci. USA

(1996)

M.B. Ruiz-Larrea et al.

Antioxidant action of estrogens in rat hepatocytes

Rev. Esp. Fisiol

(1997)

V.W. Henderson et al.

Estrogen for Alzheimer’s disease in women. Randomized, double-blind, placebo-controlled trial

Neurology

(2000)

Z. Medvedev

An attempt at a rational classification of theories of ageing

Biol. Rev. Camb. Philos. Soc

(1990)

D. Harman

Aginga theory based on free radical and radiation chemistry

J. Gerontol

(1956)

K.B. Beckman et al.

The free radical theory of aging matures

Physiol. Rev

(1998)

M. Lopez Torres et al.

Maximum life span in vertebratesrelationship with liver antioxidant enzymes, glutathione system, ascorbate, urate sensitivity to peroxidation, true malondialdehyde, in vivo H₂O₂ and basal and maximum aerobic capacity

Mech. Aging Dev

(1993)

Cited by (516)

Fatty acid oxidation drives mitochondrial hydrogen peroxide production by α-ketoglutarate dehydrogenase
2024, Journal of Biological Chemistry
In the present study, we examined the mitochondrial hydrogen peroxide (mH₂O₂) generating capacity of α-ketoglutarate dehydrogenase (KGDH) and compared it to components of the electron transport chain using liver mitochondria isolated from male and female C57BL6N mice. We show for the first time there are some sex dimorphisms in the production of mH₂O₂ by electron transport chain complexes I and III when mitochondria are fueled with different substrates. However, in our investigations into these sex effects, we made the unexpected and compelling discovery that 1) KGDH serves as a major mH₂O₂ supplier in male and female liver mitochondria and 2) KGDH can form mH₂O₂ when liver mitochondria are energized with fatty acids but only when malate is used to prime the Krebs cycle. Surprisingly, 2-keto-3-methylvaleric acid (KMV), a site-specific inhibitor for KGDH, nearly abolished mH₂O₂ generation in both male and female liver mitochondria oxidizing palmitoyl-carnitine. KMV inhibited mH₂O₂ production in liver mitochondria from male and female mice oxidizing myristoyl-, octanoyl-, or butyryl-carnitine as well. S1QEL 1.1 (S1) and S3QEL 2 (S3), compounds that inhibit reactive oxygen species generation by complexes I and III, respectively, without interfering with OxPhos and respiration, had a negligible effect on the rate of mH₂O₂ production when pyruvate or acyl-carnitines were used as fuels. However, inclusion of KMV in reaction mixtures containing S1 and/or S3 almost abolished mH₂O₂ generation. Together, our findings suggest KGDH is the main mH₂O₂ generator in liver mitochondria, even when fatty acids are used as fuel.
Sex-specific antioxidant biomarker depletion in patients with a history of mild traumatic brain injury
2024, Advances in Redox Research
Individuals with a history of mild traumatic brain injury (mTBI) are at an increased risk for neurodegenerative disease, suggesting that intrinsic neuroprotective mechanisms, such as the endogenous antioxidant reservoir, may be depleted long-term after mTBI. Here, we retrospectively analyzed symptoms and blood antioxidants in patients with a history of mTBI who presented to Resilience Code, a sports medicine clinic in Colorado. Significant decreases in alpha-tocopherol, selenium, linoleic acid, taurine, docosahexaenoic acid, and total omega-3 were measured in the total mTBI population versus controls. Male mTBI patients showed depletion of a larger array of antioxidants than females. Patients with a history of mTBI also reported significantly worsened emotional, energy, head, and cognitive symptoms, with males displaying more extensive symptomology. Multiple or chronic mTBI patients had worsened symptoms than single or acute/subchronic mTBI patients, respectively. Finally, male mTBI patients with the largest reductions in polyunsaturated fatty acids (PUFAs) displayed worse symptomology than male mTBI patients with less depletion of this antioxidant reservoir. These results demonstrate that antioxidant depletion persists in patients with a history of mTBI and these deficits are sex-specific and associated with worsened symptomology. Furthermore, supplementation with specific antioxidants, like PUFAs, may diminish symptom severity in patients suffering from chronic effects of mTBI.
Analysis of the cognitive and functional behavior of female rats in the periestropause after hormone therapy with estrogen
2024, Behavioural Brain Research
Perimenopause is a critical period, with severe cycle irregularity and lower estrogen secretion altering redox state biomarkers, leading to behavioral changes. The estrogen hormonal therapy (EHT) being commonly used to alleviate climacteric effects. Therefore, the aim of this study was to analyze anxiolytic profile, recognition memory (short and long term), ambulation, redox status, cell synaptic activity in locus coeruleus and hippocampus of Wistar rats in the periestropause after EHT. Forty rats participated in the study; 20 were treated with corn oil (group 21Mo/Veh; corn oil/0.2 mL/sc; 2x/week) and 20 were submitted to EHT (group 21Mo/E2; 17β-estradiol/15 μg/Kg/sc; 2x/week) for 120 days. Open field, elevated plus maze, object recognition (RO), and footprint tests were performed immediately before and at the end of the treatment period. From the decapitated brains, isolated hippocampus were destined for biochemical analysis, in turn, perfused brains were destined for histological analysis. The 21Mo/E2 group had a significantly greater total time in the central region and a significantly greater number of entries into the open arms compared to the 21Mo/Veh group, as in crossing, rearing and grooming behaviors, evidencing an anxiolytic profile. In the RO test, the 21Mo/Veh group decreased long-term memory, and the 21Mo/E2 group maintained the same index as at 17 months of age, in addition to a better balance of the hippocampal redox state, prevention of neuronal cell loss and better gait. Based on the results, it appears that exogenous E2 supplementation during periestropause may help preserve neurological functions and potentially prevent neuropsychological and neurodegenerative disorders.
Zeaxanthin exerts anti-inflammatory effects in vitro and provides significant neuroprotection in mice subjected to transient middle cerebral artery occlusion
2024, PharmaNutrition
Preclinical and clinical evidence supports the value of nutraceuticals as prophylactic or adjuvant therapeutics to reduce stroke risk or to improve post-stroke recovery. Given the beneficial properties of xantophyll carotenoids, we aimed at assessing the putative neuroprotective effects of zeaxanthin, evaluating its anti-inflammatory and anti-oxidant properties in vitro and in vivo.
Exposure to zeaxanthin (25 μM for 24 h) reverted the elevation of inducible nitric oxide synthase (iNOS) expression prompted by tumor necrosis factor (TNF)-α in macrophages from mouse bone marrow. In mice subjected to transient (30-min) middle cerebral artery occlusion (MCAo), oral pre-treatment with zeaxanthin (2 mg/kg, 48 h, 24 h and 1 h before MCAo) prevented the elevation of serum levels of reactive oxygen species induced by the ischemic insult, while it did not affect the reduction of antioxidant barrier efficiency. Analysis of lipid peroxidation showed a significant increase in hydroperoxide level in the brain of mice subjected to MCAo, and the latter effect was inhibited by pretreatment with zeaxanthin. Finally, we originally demonstrated that oral administration of zeaxanthin significantly reduced neurological deficits and brain damage caused by transient MCAo in mice.
Our data, in combination with the evidence that zeaxanthin is a well-tolerated carotenoid, strengthen the nutritional value of this xanthophyll in the prevention of ischemic stroke injury.
Sex differences in frailty among older adults
2023, Experimental Gerontology
By definition, aging is a natural, gradual and continuous process. On the other hand, frailty reflects the increase in vulnerability to stressors and shortens the time without disease (health span) while longevity refers to the length of life (lifespan). The average life expectancy has significantly increased during the last few decades. A longer lifespan has been accompanied by an increase in frailty and decreased independence in older adults, with major differences existing between men and women. For example, women tend to live longer than men but also experience higher rates of frailty and disability. Sex differences prevent optimization of lifestyle interventions and therapies to effectively prevent frailty. Sex differences in frailty and aging are rooted in a complex interplay between uncontrollable (genetic, epigenetic, physiological), and controllable factors (psychosocial and lifestyle factors). Thus, understanding the underlying causes of sex differences in frailty and aging is essential for developing personalized interventions to promote healthy aging and improve quality of life in older men and women. In this review, we have discussed the key contributors and knowledge gaps related to sex differences in aging and frailty.
Mitochondrial network adaptations of microglia reveal sex-specific stress response after injury and UCP2 knockout
2023, iScience
Mitochondrial networks remodel their connectivity, content, and subcellular localization to support optimized energy production in conditions of increased environmental or cellular stress. Microglia rely on mitochondria to respond to these stressors, however our knowledge about mitochondrial networks and their adaptations in microglia in vivo is limited. Here, we generate a mouse model that selectively labels mitochondria in microglia. We identify that mitochondrial networks are more fragmented with increased content and perinuclear localization in vitro vs. in vivo. Mitochondrial networks adapt similarly in microglia closest to the injury site after optic nerve crush. Preventing microglial UCP2 increase after injury by selective knockout induces cellular stress. This results in mitochondrial hyperfusion in male microglia, a phenotype absent in females due to circulating estrogens. Our results establish the foundation for mitochondrial network analysis of microglia in vivo, emphasizing the importance of mitochondrial-based sex effects of microglia in other pathologies.

View all citing articles on Scopus

View full text

Original contributionMitochondria from females exhibit higher antioxidant gene expression and lower oxidative damage than males