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1.
Nutrients ; 15(12)2023 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-37375594

RESUMO

Despite the reported prevalence of micronutrient deficiencies in older adults, it is not yet established whether multivitamin/multimineral (MV/MM) supplements improve blood micronutrient status in individuals over the age of 65. Therefore, a cohort of 35 healthy men (>67 years) was recruited for an MV/MM supplementation trial. The primary endpoint was, as an indicator of micronutrient status, changes in blood micronutrient biomarkers from baseline to at least six months of supplementation with MV/MM or placebo. The secondary endpoint was basal O2 consumption in monocytes as an indicator of cellular metabolism. MV/MM supplementation improved blood concentrations of pyridoxal phosphate, calcifediol, α-tocopherol, and ß-carotene concentrations throughout the cohort. By contrast, those in the placebo group generally showed declines in blood vitamin concentrations and an increased prevalence of suboptimal vitamin status during the study period. On the other hand, MV/MM supplementation did not significantly affect blood mineral concentrations, i.e., calcium, copper, iron, magnesium, and zinc. Interestingly, MV/MM supplementation prevented the decline in monocyte O2 consumption rate. Overall, MV/MM use improves or prevents declines in vitamin, but not mineral, status and limits declines in cellular O2 consumption, which may have important implications for metabolism and immune health in healthy older men.


Assuntos
Oligoelementos , Vitaminas , Masculino , Humanos , Idoso , Suplementos Nutricionais , Minerais , Micronutrientes , Biomarcadores , Metabolismo Energético , Método Duplo-Cego
2.
Clin Biomech (Bristol, Avon) ; 101: 105863, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36549050

RESUMO

BACKGROUND: Tailored, challenging and progressed exercise programs addressing risk factors are recommended for preventing falls in community-dwelling older adults. Knowing the biomechanical demands of exercises commonly performed in efficacious falls prevention programs provides evidence for exercise prescription. METHODS: Twenty-one non-sedentary older adults (10 men, 11 women, mean age 69 [SD 5] years) performed five standing exercises (hip abduction, side-step, squat, forward lunge, and side lunge). A biomechanical analysis of the dominant limb was performed to calculate peak joint angles and net joint moments at the ankle, knee and hip in multiple planes. Repeated-measures one-way analyses of variance followed by post-hoc comparisons were performed to identify differences in the calculated variables between exercises. FINDINGS: Peak hip abduction moments during hip abduction were greater than during the forward lunge and squat (P < 0.001). During the side-step, peak plantar flexion moments were greater than the squat and peak hip abduction moments were greater than the squat and forward lunge (P < 0.001). During the squat, peak hip flexion was greatest (P < 0.001) while peak plantar flexion (P < 0.001) and hip abduction moments (P ≤ 0.002) were less than all other exercises. During the forward lunge, peak hip extension moments (P < 0.001) were greatest. During the side lunge, peak knee extension moments were greater than all other exercises (P < 0.001). INTERPRETATION: These biomechanical data will allow clinicians to tailor exercises for falls prevention to efficiently challenge but not overload muscle groups and minimize exercise prescription redundancies.


Assuntos
Terapia por Exercício , Exercício Físico , Masculino , Humanos , Feminino , Idoso , Exercício Físico/fisiologia , Extremidade Inferior/fisiologia , Joelho/fisiologia , Articulação do Joelho/fisiologia , Fenômenos Biomecânicos/fisiologia
3.
Free Radic Biol Med ; 178: 330-346, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34890770

RESUMO

Mitochondria serve vital roles critical for overall cellular function outside of energy transduction. Thus, mitochondrial decay is postulated to be a key factor in aging and in age-related diseases. Mitochondria may be targets of their own decay through oxidative damage. However, treating animals with antioxidants has been met with only limited success in rejuvenating mitochondrial function or in increasing lifespan. A host of nutritional strategies outside of using traditional antioxidants have been devised to promote mitochondrial function. Dietary compounds are under study that induce gene expression, enhance mitochondrial biogenesis, mitophagy, or replenish key metabolites that decline with age. Moreover, redox-active compounds may now be targeted to mitochondria which improve their effectiveness. Herein we review the evidence that representative dietary effectors modulate mitochondrial function by stimulating their renewal or reversing the age-related loss of key metabolites. While in vitro evidence continues to accumulate that many of these compounds benefit mitochondrial function and/or prevent their decay, the results using animal models and, in some instances human clinical trials, are more mixed and sometimes even contraindicated. Thus, further research on optimal dosage and age of intervention are warranted before recommending potential mitochondrial rejuvenating compounds for human use.


Assuntos
Produtos Biológicos , Animais , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Produtos Biológicos/metabolismo , Produtos Biológicos/farmacologia , Humanos , Mitocôndrias/metabolismo , Mitofagia , Estresse Oxidativo
4.
J Gerontol A Biol Sci Med Sci ; 77(2): 283-290, 2022 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-34871395

RESUMO

The mitochondrial oxidative stress theory of aging suggests that the organelle's decay contributes to the aging phenotype via exacerbated oxidative stress, loss of organ coordination and energetics, cellular integrity, and activity of the mitochondrial electron transfer system (ETS). Recent advances in understanding the structure of the ETS show that the enzymatic complexes responsible for oxidative phosphorylation are arranged in supramolecular structures called supercomplexes that lose organization during aging. Their exact role and universality among organisms are still under debate. Here, we take advantage of marine bivalves as an aging model to compare the structure of the ETS among species ranging from 28 to 507 years in maximal life span. Our results show that regardless of life span, the bivalve ETS is arrayed as a set of supercomplexes. However, bivalve species display varying degrees of ETS supramolecular organization with the highest supercomplex structures found in Arctica islandica, the longest-lived of the bivalve species under study. We discuss this comparative model in light of differences in the nature and stoichiometry of these complexes and highlight the potential link between the complexity of these superstructures and longer life spans.


Assuntos
Bivalves , Longevidade , Animais , Bivalves/genética , Respiração Celular , Transporte de Elétrons , Elétrons , Longevidade/genética
5.
J Gerontol A Biol Sci Med Sci ; 76(5): 796-804, 2021 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-33257932

RESUMO

The role played by mitochondrial function in the aging process has been a subject of intense debate in the past few decades, as part of the efforts to understand the mechanistic basis of longevity. The mitochondrial oxidative stress theory of aging suggests that a progressive decay of this organelle's function leads to an exacerbation of oxidative stress, with a deleterious impact on mitochondrial structure and DNA, ultimately promoting aging. Among the traits suspected to be associated with longevity is the variation in the regulation of oxidative phosphorylation, potentially affecting the management of oxidative stress. Longitudinal studies using the framework of metabolic control analysis have shown age-related differences in the flux control of respiration, but this approach has seldom been taken on a comparative scale. Using 4 species of marine bivalves exhibiting a large range of maximum life span (from 28 years to 507 years), we report life-span-related differences in flux control at different steps of the electron transfer system. Increased longevity was characterized by a lower control by NADH (complex I-linked) and Succinate (complex II-linked) pathways, while respiration was strongly controlled by complex IV when compared to shorter-lived species. Complex III exerted strong control over respiration in all species. Furthermore, high longevity was associated with higher citrate synthase activity and lower ATP synthase activity. Relieving the control exerted by the electron entry pathways could be advantageous for reaching higher longevity, leading to increased control by complex IV, the final electron acceptor in the electron transfer system.


Assuntos
Bivalves/metabolismo , Longevidade/genética , Mitocôndrias/metabolismo , Animais , Bivalves/genética , Bivalves/crescimento & desenvolvimento , Respiração Celular/fisiologia , Transporte de Elétrons/fisiologia , Complexo IV da Cadeia de Transporte de Elétrons/fisiologia , NAD/metabolismo , Estresse Oxidativo/fisiologia , Ácido Succínico/metabolismo
6.
J Nutr ; 150(9): 2336-2345, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32692358

RESUMO

BACKGROUND: α-Lipoic acid (LA) is a dietary supplement for maintaining energy balance, but well-controlled clinical trials in otherwise healthy, overweight adults using LA supplementation are lacking. OBJECTIVES: The primary objective was to evaluate whether LA supplementation decreases elevated plasma triglycerides in overweight or obese adults. Secondary aims examined if LA promotes weight loss and improves oxidative stress and inflammation. METHODS: Overweight adults [n = 81; 57% women; 21-60 y old; BMI (in kg/m2) ≥ 25] with elevated plasma triglycerides ≥100 mg/dL were enrolled in a 24-wk, randomized, double-blind, controlled trial, assigned to either (R)-α-lipoic acid (R-LA; 600 mg/d) or matching placebo, and advised not to change their diet or physical activity. Linear models were used to evaluate treatment effects from baseline for primary and secondary endpoints. RESULTS: R-LA did not decrease triglyceride concentrations, but individuals on R-LA had a greater reduction in BMI at 24 wk than the placebo group (-0.8; P = 0.04). The effect of R-LA on BMI was correlated to changes in plasma triglycerides (r = +0.50, P = 0.004). Improvement in body weight was greater at 24 wk in R-LA subgroups than in placebo subgroups. Women and obese participants (BMI ≥ 35) showed greater weight loss (-5.0% and -4.8%, respectively; both P < 0.001) and loss of body fat (-9.4% and -8.6%, respectively; both P < 0.005). Antioxidant gene expression in mononuclear cells at 24 wk was greater in the R-LA group (Heme oxygenase 1 [HMOX1] : +22%; P = 0.02) than in placebo. Less urinary F2-isoprostanes (-25%; P = 0.005), blood leukocytes (-10.1%; P = 0.01), blood thrombocytes (-5.1%; P = 0.03), and ICAM-1 (-7.4%; P = 0.04) at 24 wk were also observed in the R-LA group than in placebo. CONCLUSIONS: Long-term LA supplementation results in BMI loss, greater antioxidant enzyme synthesis, and less potential for inflammation in overweight adults. Improved cellular bioenergetics is also evident in some individuals given R-LA.This trial was registered at clinicaltrials.gov as NCT00765310.


Assuntos
Suplementos Nutricionais , Sobrepeso/tratamento farmacológico , Ácido Tióctico/administração & dosagem , Triglicerídeos/sangue , Adulto , Esquema de Medicação , Exercício Físico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Redução de Peso , Adulto Jovem
7.
Front Physiol ; 10: 946, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31404340

RESUMO

The mitochondrial oxidative stress theory of aging posits that membrane susceptibility to peroxidation and the organization of the electron transport system (ETS) linked with reactive oxygen species (ROS) generation are two main drivers of lifespan. While a clear correlation has been established from species comparative studies, the significance of these characteristics as potential modulators of lifespan divergences among populations of individual species is still to be tested. The bivalve Arctica islandica, the longest-lived non-colonial animal with a record lifespan of 507 years, possesses a lower mitochondrial peroxidation index (PI) and reduced H2O2 efflux linked to complexes I and III activities than related species. Taking advantage of the wide variation in maximum reported longevities (MRL) among 6 European populations (36-507 years), we examined whether these two mitochondrial properties could explain differences in longevity. We report no relationship between membrane PI and MRL in populations of A. islandica, as well as a lack of intraspecific relationship between ETS complex activities and MRL. Individuals from brackish sites characterized by wide temperature and salinity windows had, however, markedly lower ETS enzyme activities relative to citrate synthase activity. Our results highlight environment-dependent remodeling of mitochondrial phenotypes.

8.
Redox Biol ; 22: 101155, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30851669

RESUMO

The role of mitochondrial GSH (mGSH) in the enhanced age-related susceptibility to xenobiotic toxicity is not well defined. We determined mGSH status and indices of mitochondrial bioenergetics in hepatocytes from young and old F344 rats treated with 300 µM menadione, a concentration that causes 50% cell death in old. At this concentration, mGSH was significantly lost only in hepatocytes from old rats, and with near total depletion due to lower basal mGSH in aged cells. In old hepatocytes, menadione caused mitochondrial membrane potential to collapse, as well as significant deficits in maximal O2 consumption and respiratory reserve capacity, indicators of cellular bioenergetic resiliency. Further examination revealed that the menadione-mediated loss of respiratory reserve capacity in aged hepatocytes was from significant inhibition of Complex I activity and increased proton leak, for which an increase in Complex II activity was not able to compensate. These data demonstrate an age-related increase in mitochondrial susceptibility to a redox-cycling challenge, particularly in regards to Complex I activity, and provide a plausible mechanism to link this vulnerability to mGSH perturbations.


Assuntos
Complexo I de Transporte de Elétrons/antagonistas & inibidores , Complexo I de Transporte de Elétrons/metabolismo , Glutationa/metabolismo , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Vitamina K 3/farmacologia , Fatores Etários , Animais , Respiração Celular , Relação Dose-Resposta a Droga , Hepatócitos/metabolismo , Masculino , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias Hepáticas/efeitos dos fármacos , Mitocôndrias Hepáticas/metabolismo , Oxirredução , Estresse Oxidativo , Ratos
9.
Redox Biol ; 10: 45-52, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27687220

RESUMO

Isolated hepatocytes from young (4-6mo) and old (24-26mo) F344 rats were exposed to increasing concentrations of menadione, a vitamin K derivative and redox cycling agent, to determine whether the age-related decline in Nrf2-mediated detoxification defenses resulted in heightened susceptibility to xenobiotic insult. An LC50 for each age group was established, which showed that aging resulted in a nearly 2-fold increase in susceptibility to menadione (LC50 for young: 405µM; LC50 for old: 275µM). Examination of the known Nrf2-regulated pathways associated with menadione detoxification revealed, surprisingly, that NAD(P)H: quinone oxido-reductase 1 (NQO1) protein levels and activity were induced 9-fold and 4-fold with age, respectively (p=0.0019 and p=0.018; N=3), but glutathione peroxidase 4 (GPX4) declined by 70% (p=0.0043; N=3). These results indicate toxicity may stem from vulnerability to lipid peroxidation instead of inadequate reduction of menadione semi-quinone. Lipid peroxidation was 2-fold higher, and GSH declined by a 3-fold greater margin in old versus young rat cells given 300µM menadione (p<0.05 and p≤0.01 respectively; N=3). We therefore provided 400µMN-acetyl-cysteine (NAC) to hepatocytes from old rats before menadione exposure to alleviate limits in cysteine substrate availability for GSH synthesis during challenge. NAC pretreatment resulted in a >2-fold reduction in cell death, suggesting that the age-related increase in menadione susceptibility likely stems from attenuated GSH-dependent defenses. This data identifies cellular targets for intervention in order to limit age-related toxicological insults to menadione and potentially other redox cycling compounds.


Assuntos
Envelhecimento/metabolismo , Glutationa/metabolismo , Hepatócitos/efeitos dos fármacos , Oxirredução/efeitos dos fármacos , Vitamina K 3/toxicidade , Acetilcisteína/farmacologia , Animais , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Glutationa Peroxidase/metabolismo , Hepatócitos/citologia , Hepatócitos/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , NAD(P)H Desidrogenase (Quinona)/metabolismo , Fosfolipídeo Hidroperóxido Glutationa Peroxidase , Ratos , Ratos Endogâmicos F344
10.
Free Radic Biol Med ; 89: 1184-91, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26549877

RESUMO

Nrf2 regulates the expression of numerous anti-oxidant, anti-inflammatory, and metabolic genes. We observed that, paradoxically, Nrf2 protein levels decline in the livers of aged rats despite the inflammatory environment evident in that organ. To examine the cause(s) of this loss, we investigated the age-related changes in Nrf2 protein homeostasis and activation in cultured hepatocytes from young (4-6 months) and old (24-28 months) Fischer 344 rats. While no age-dependent change in Nrf2 mRNA levels was observed (p>0.05), Nrf2 protein content, and the basal and anetholetrithione (A3T)-induced expression of Nrf2-dependent genes were attenuated with age. Conversely, overexpression of Nrf2 in cells from old animals reinstated gene induction. Treatment with A3T, along with bortezomib to inhibit degradation of existing protein, caused Nrf2 to accumulate significantly in cells from young animals (p<0.05), but not old, indicating a lack of new Nrf2 synthesis. We hypothesized that the loss of Nrf2 protein synthesis with age may partly stem from an age-related increase in microRNA inhibition of Nrf2 translation. Microarray analysis revealed that six microRNAs significantly increase >2-fold with age (p<0.05). One of these, miRNA-146a, is predicted to bind Nrf2 mRNA. Transfection of hepatocytes from young rats with a miRNA-146a mimic caused a 55% attenuation of Nrf2 translation that paralleled the age-related loss of Nrf2. Overall, these results provide novel insights for the age-related decline in Nrf2 and identify new targets to maintain Nrf2-dependent detoxification with age.


Assuntos
Envelhecimento/fisiologia , Hepatócitos/metabolismo , Homeostase/genética , MicroRNAs/genética , Fator 2 Relacionado a NF-E2/metabolismo , Biossíntese de Proteínas/genética , Animais , Células Cultivadas , Hepatócitos/citologia , Masculino , Fator 2 Relacionado a NF-E2/genética , RNA Mensageiro/genética , Ratos , Ratos Endogâmicos F344 , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa
11.
Annu Rev Nutr ; 33: 45-70, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23642198

RESUMO

New evidence for the regulation of vitamin C homeostasis has emerged from several studies of human genetic variation. Polymorphisms in the genes encoding sodium-dependent vitamin C transport proteins are strongly associated with plasma ascorbate levels and likely impact tissue cellular vitamin C status. Furthermore, genetic variants of proteins that suppress oxidative stress or detoxify oxidatively damaged biomolecules, i.e., haptoglobin, glutathione-S-transferases, and possibly manganese superoxide dismutase, affect ascorbate levels in the human body. There also is limited evidence for a role of glucose transport proteins. In this review, we examine the extent of the variation in these genes, their impact on vitamin C status, and their potential role in altering chronic disease risk. We conclude that future epidemiological studies should take into account genetic variation in order to successfully determine the role of vitamin C nutriture or supplementation in human vitamin C status and chronic disease risk.


Assuntos
Ácido Ascórbico/metabolismo , Variação Genética , Homeostase , Oxirredutases/metabolismo , Transportadores de Sódio Acoplados à Vitamina C/genética , Animais , Transporte Biológico , Humanos , Transportadores de Sódio Acoplados à Vitamina C/metabolismo
12.
Pharmacol Res ; 66(3): 199-206, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22609537

RESUMO

Lipoic acid (LA) shows promise as a beneficial micronutrient toward improving elder health. Studies using old rats show that (R)-α-LA (R-LA) significantly increases low molecular weight antioxidants that otherwise decline with age. Despite this rationale for benefiting human health, little is known about age-associated alterations in absorption characteristics of LA, or whether the commercially available racemic mixture of LA (R,S-LA) is equally as bioavailable as the naturally occurring R-enantiomer. To address these discrepancies, a pilot study was performed to establish which form of LA is most effectively absorbed in older subjects relative to young volunteers. Young adults (average age=32 years) and older adults (average age=79 years) each received 500 mg of either R- or R,S-LA. Blood samples were collected for 3h after supplementation. After a washout period they were given the other chiral form of LA not originally ingested. Results showed that 2 out of 6 elder males exhibited greater maximal plasma LA and area under the curve for the R-form of LA versus the racemic mixture. The elder subjects also demonstrated a reduced time to reach maximal plasma LA concentration following R-LA supplementation than for the racemic mixture. In contrast, young males had a tendency for increased bioavailability of R,S-LA. Overall, bioavailability for either LA isoform was much more variable between older subjects compared to young adults. Plasma glutathione levels were not altered during the sampling period. Thus subject age, and potential for varied response, should be considered when determining an LA supplementation regimen.


Assuntos
Ácido Tióctico/farmacocinética , Adulto , Fatores Etários , Idoso , Antioxidantes/metabolismo , Disponibilidade Biológica , Suplementos Nutricionais , Feminino , Glutationa/metabolismo , Humanos , Masculino , Projetos Piloto , Fatores Sexuais , Estereoisomerismo , Ácido Tióctico/sangue , Ácido Tióctico/química , Ácido Tióctico/farmacologia
13.
Semin Cell Dev Biol ; 23(7): 758-67, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22521482

RESUMO

Mitochondrial decay plays a central role in the aging process. Although certainly multifactorial in nature, defective operation of the electron transport chain (ETC) constitutes a key mechanism involved in the age-associated loss of mitochondrial energy metabolism. Primarily, mitochondrial dysfunction affects the aging animal by limiting bioenergetic reserve capacity and/or increasing oxidative stress via enhanced electron leakage from the ETC. Even though the important aging characteristics of mitochondrial decay are known, the molecular events underlying inefficient electron flux that ultimately leads to higher superoxide appearance and impaired respiration are not completely understood. This review focuses on the potential role(s) that age-associated destabilization of the macromolecular organization of the ETC (i.e. supercomplexes) may be important for development of the mitochondrial aging phenotype, particularly in post-mitotic tissues.


Assuntos
Metabolismo Energético , Mitocôndrias/metabolismo , Estresse Oxidativo , Superóxidos/metabolismo , Envelhecimento , Animais , Humanos , Metabolismo dos Lipídeos
14.
Biochim Biophys Acta ; 1823(6): 1102-9, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22521877

RESUMO

Little is known about either the basal or stimulated homeostatic mechanisms regulating nuclear tenure of Nf-e2-related factor 2 (Nrf2), a transcription factor that mediates expression of over 200 detoxification genes. Our data show that stress-induced nuclear Nrf2 accumulation is largely from de novo protein synthesis, rather than translocation from a pre-existing cytoplasmic pool. HepG2 cells were used to monitor nuclear Nrf2 24h following treatment with the dithiol micronutrient (R)-α-lipoic acid (LA; 50µM), or vehicle. LA caused a ≥2.5-fold increase in nuclear Nrf2 within 1h. However, pretreating cells with cycloheximide (50µg/ml) inhibited LA-induced Nrf2 nuclear accumulation by 94%. Providing cells with the mTOR inhibitor, rapamycin, decreased basal Nrf2 levels by 84% after 4h, but LA overcame this inhibition. LA-mediated de novo protein translation was confirmed using HepG2 cells transfected with a bicistronic construct containing an internal ribosome entry sequence (IRES) for Nrf2, with significant (P<0.05) increase in IRES use under LA treatment. These results suggest that a dithiol stimulus mediates Nrf2 nuclear tenure via cap-independent protein translation. Thus, translational control of Nrf2 synthesis, rather than reliance solely on pre-existing protein, may mediate the rapid burst of Nrf2 nuclear accumulation following stress stimuli.


Assuntos
Inativação Metabólica , Fator 2 Relacionado a NF-E2/biossíntese , Biossíntese de Proteínas/efeitos dos fármacos , Capuzes de RNA/metabolismo , Estresse Fisiológico/efeitos dos fármacos , Ácido Tióctico/farmacologia , Sequência de Bases , Compartimento Celular/efeitos dos fármacos , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Células Hep G2 , Humanos , Complexo de Endopeptidases do Proteassoma/metabolismo , Inibidores de Proteassoma , Capuzes de RNA/efeitos dos fármacos , Sirolimo/farmacologia
15.
Mech Ageing Dev ; 133(2-3): 99-106, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22322067

RESUMO

The aging heart displays a loss of bioenergetic reserve capacity partially mediated through lower fatty acid utilization. We investigated whether the age-related impairment of cardiac fatty acid catabolism occurs, at least partially, through diminished levels of L-carnitine, which would adversely affect carnitine palmitoyltransferase 1 (CPT1), the rate-limiting enzyme for fatty acyl-CoA uptake into mitochondria for ß-oxidation. Old (24-28 mos) Fischer 344 rats were fed±acetyl-L-carnitine (ALCAR; 1.5% [w/v]) for up to four weeks prior to sacrifice and isolation of cardiac interfibrillar (IFM) and subsarcolemmal (SSM) mitochondria. IFM displayed a 28% (p<0.05) age-related loss of CPT1 activity, which correlated with a decline (41%, p<0.05) in palmitoyl-CoA-driven state 3 respiration. Interestingly, SSM had preserved enzyme function and efficiently utilized palmitate. Analysis of IFM CPT1 kinetics showed both diminished V(max) and K(m) (60% and 49% respectively, p<0.05) when palmitoyl-CoA was the substrate. However, no age-related changes in enzyme kinetics were evident with respect to L-carnitine. ALCAR supplementation restored CPT1 activity in heart IFM, but not apparently through remediation of L-carnitine levels. Rather, ALCAR influenced enzyme activity over time, potentially by modulating conditions in the aging heart that ultimately affect palmitoyl-CoA binding and CPT1 kinetics.


Assuntos
Acetilcarnitina/metabolismo , Carnitina O-Palmitoiltransferase/genética , Carnitina O-Palmitoiltransferase/metabolismo , Carnitina/metabolismo , Suplementos Nutricionais , Miocárdio/metabolismo , Fatores Etários , Animais , Cinética , Masculino , Mitocôndrias/metabolismo , Mitocôndrias Cardíacas/metabolismo , Modelos Biológicos , Palmitoil Coenzima A/metabolismo , Ratos , Ratos Endogâmicos F344
16.
Aging Cell ; 11(2): 297-304, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22212472

RESUMO

NFE2-related factor 2 (Nrf2) transcriptionally governs the cellular response to harmful electrophiles, xenobiotics, and reactive oxygen species. Its nuclear levels decline with age (Suh et al., 2004a), which in part explains the age-related loss of phase II detoxification. However, little work has yet characterized how age affects Nrf2 DNA binding or the role that alterations to the Nrf2 transcriptional apparatus plays in modulating Nrf2-mediated gene expression. In this study, we used immunoprecipitation assays to show that Nrf2 bound to the active antioxidant response element (ARE) of the catalytic subunit of glutamate cysteine ligase (GCLC) is significantly lower in hepatic chromatin from aged vs. young rats. Moreover, the activity at this ARE locus is diminished during aging because of the presence of Bach1 and the absence of CREB-binding protein (CBP), a transcriptional repressor and co-activator, respectively. Further analysis reveals that Nrf2 occupies an alternate ARE site located -2.2 kb downstream from the normally active ARE binding site in livers of old rats, indicating an age-specific adaptation to maintain gene expression. Our results, thus, show that the conversion of Nrf2 binding from an active ARE to an alternative ARE element is not adequate to maintain basal expression of hepatic Gclc in old rats, which provides a potential mechanism for the age-related loss of glutathione synthetic and other phase II enzymes.


Assuntos
Envelhecimento , Antioxidantes/metabolismo , Glutamato-Cisteína Ligase/metabolismo , Glutationa/biossíntese , Fígado/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Elementos de Resposta , Animais , Células Cultivadas , Loci Gênicos , Masculino , Ligação Proteica , Ratos , Ratos Endogâmicos F344
17.
Am J Physiol Regul Integr Comp Physiol ; 302(5): R587-97, 2012 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-22049228

RESUMO

To determine the effects of age and lipoic acid supplementation on hepatic gene expression, we fed young (3 mo) and old (24 mo) male Fischer 344 rats a diet with or without 0.2% (wt/wt) R-α-lipoic acid (LA) for 2 wk. Total RNA isolated from liver tissue was analyzed by Affymetrix microarray to examine changes in transcriptional profiles. Results showed elevated proinflammatory gene expression in the aging liver and evidence for increased immune cell activation and tissue remodeling, together representing 45% of the age-related transcriptome changes. In addition, age-related increases in transcripts of genes related to fatty acid, triglyceride, and cholesterol synthesis, including acetyl-CoA carboxylase-ß (Acacb) and fatty acid synthase (Fasn), were observed. Supplementation of old animals with LA did not reverse the necroinflammatory phenotype but, intriguingly, altered the expression of genes governing circadian rhythm. Most notably, Arntl, Npas2, and Per changed in a coordinated manner with respect to rhythmic transcription. LA further caused a decrease in transcripts of several bile acid and lipid synthesis genes, including Acacb and Fasn, which are regulated by first-order clock transcription factors. Similar effects of LA supplementation on bile acid and lipid synthesis genes were observed in young animals. Transcript changes of lipid metabolism genes were corroborated by a decrease in FASN and ACC protein levels. We conclude that advanced age is associated with a necroinflammatory phenotype and increased lipid synthesis, while chronic LA supplementation influences hepatic genes associated with lipid and energy metabolism and circadian rhythm, regardless of age.


Assuntos
Envelhecimento/efeitos dos fármacos , Ritmo Circadiano/efeitos dos fármacos , Perfilação da Expressão Gênica , Hepatite/prevenção & controle , Metabolismo dos Lipídeos/efeitos dos fármacos , Ácido Tióctico/farmacologia , Ácido Tióctico/uso terapêutico , Fatores de Transcrição ARNTL/genética , Fatores de Transcrição ARNTL/metabolismo , Envelhecimento/metabolismo , Animais , Ritmo Circadiano/genética , Peptídeos e Proteínas de Sinalização do Ritmo Circadiano/genética , Peptídeos e Proteínas de Sinalização do Ritmo Circadiano/metabolismo , Suplementos Nutricionais , Metabolismo Energético/efeitos dos fármacos , Metabolismo Energético/fisiologia , Expressão Gênica/efeitos dos fármacos , Expressão Gênica/fisiologia , Hepatite/genética , Hepatite/metabolismo , Metabolismo dos Lipídeos/fisiologia , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Modelos Animais , Proteínas Circadianas Period/genética , Proteínas Circadianas Period/metabolismo , Ratos , Ratos Endogâmicos F344 , Ácido Tióctico/administração & dosagem
18.
Pharmacol Res ; 64(5): 431-7, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21745572

RESUMO

The use of antioxidants is now often used as a pharmacological adjunct to limit infertility. Indeed, the lay public rightly perceives oxidative stress and, thus, antioxidant treatment as important modulators of infertility. While the direct effects of antioxidant treatment on the quality of semen and oocytes are still under investigation, a significant body of evidence points to loss of vascular tone as a root-cause of erectile dysfunction and, possibly, alterations to female reproduction. In this article, we will critically review the often neglected link between vascular dysfunction and infertility. A particular emphasis will be on the potential use of antioxidants to increase fertility and promote conception.


Assuntos
Antioxidantes/uso terapêutico , Infertilidade/tratamento farmacológico , Óxido Nítrico Sintase Tipo III/metabolismo , Animais , Antioxidantes/farmacologia , Feminino , Fertilidade/efeitos dos fármacos , Fertilização/efeitos dos fármacos , Humanos , Masculino
19.
Pharmacol Res ; 63(1): 23-9, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20934512

RESUMO

Inflammation results in heightened mitochondrial ceramide levels, which cause electron transport chain dysfunction, elevates reactive oxygen species, and increases apoptosis. As mitochondria in aged hearts also display many of these characteristics, we hypothesized that mitochondrial decay stems partly from an age-related ceramidosis that heretofore has not been recognized for the heart. Intact mitochondria or their purified inner membranes (IMM) were isolated from young (4-6 mo) and old (26-28 mo) rats and analyzed for ceramides by LC-MS/MS. Results showed that ceramide levels increased by 32% with age and three ceramide isoforms, found primarily in the IMM (e.g. C(16)-, C(18)-, and C(24:1)-ceramide), caused this increase. The ceramidosis may stem from enhanced hydrolysis of sphingomyelin, as neutral sphingomyelinase (nSMase) activity doubled with age but with no attendant change in ceramidase activity. Because (R)-α-lipoic acid (LA) improves many parameters of cardiac mitochondrial decay in aging and lowers ceramide levels in vascular endothelial cells, we hypothesized that LA may limit cardiac ceramidosis and thereby improve mitochondrial function. Feeding LA [0.2%, w/w] to old rats for two weeks prior to mitochondrial isolation reversed the age-associated decline in glutathione levels and concomitantly improved Complex IV activity. This improvement was associated with lower nSMase activity and a remediation in mitochondrial ceramide levels. In summary, LA treatment lowers ceramide levels to that seen in young rat heart mitochondria and restores Complex IV activity which otherwise declines with age.


Assuntos
Envelhecimento/metabolismo , Ceramidas/metabolismo , Mitocôndrias Cardíacas/efeitos dos fármacos , Ácido Tióctico/farmacologia , Administração Oral , Fatores Etários , Animais , Senescência Celular , Ceramidases/metabolismo , Cromatografia Líquida de Alta Pressão , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Glutationa/metabolismo , Hidrólise , Masculino , Mitocôndrias Cardíacas/metabolismo , Membranas Mitocondriais/efeitos dos fármacos , Membranas Mitocondriais/metabolismo , Ratos , Ratos Endogâmicos F344 , Esfingomielina Fosfodiesterase/metabolismo , Esfingomielinas/metabolismo , Espectrometria de Massas em Tandem , Ácido Tióctico/administração & dosagem
20.
Artigo em Inglês | MEDLINE | ID: mdl-22255615

RESUMO

A wearable, multi-modal sensor is presented that can non-invasively monitor a patient's activity level and heart function concurrently for more than a week. The 4 in(2) sensor incorporates both a non-contact heartrate sensor and a 5-axis inertial measurement unit (IMU), allowing simultaneous heart, respiration, and movement monitoring without requiring physical contact with the skin [1]. Hence, this Oregon State University Life and Activity Monitor (OLAM) provides the unique opportunity to combine motion data with heart-rate information, enabling assessment of actual physical activity beyond conventional movement sensors. OLAM also provides a unique platform for non-contact sensing, enabling the filtering of movement artifacts generated by the non-contact capacitive interface, using the IMU data as a movement noise channel. Intended to be used in clinical trials for weeks at a time with no physician intervention, the OLAM allows continuous non-invasive monitoring of patients, providing the opportunity for long-term observation into a patient's physical activity and subtle longitudinal changes.


Assuntos
Aceleração , Actigrafia/instrumentação , Eletrocardiografia Ambulatorial/instrumentação , Frequência Cardíaca/fisiologia , Atividade Motora/fisiologia , Processamento de Sinais Assistido por Computador/instrumentação , Telemetria/instrumentação , Humanos , Transdutores
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