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1.
Mol Cell Biochem ; 431(1-2): 97-102, 2017 Jul.
Article in English | MEDLINE | ID: mdl-28255846

ABSTRACT

Like mitochondria, peroxisomes produce reactive oxygen species (ROS), compounds which have been implicated to play an important role in many degenerative diseases and aging itself, and an exaggerated ROS production might occur in altered or older organelles. Growing evidence shows that autophagy, a required function in cell housekeeping during fasting, can remove damaged macromolecules, organelles, and membranes selectively. Proliferation of peroxisomes can be enhanced in liver cells by perfluorooctanoic acid (PFOA), which causes a marked increase of the Acyl-CoA oxidase (ACOX) activity and no significant change in urate oxidase (UOX) activity. The administration of antilipolytic drugs to fasted animals was shown to intensify autophagy. Here we tested the hypothesis that autophagy may distinguish and remove older from younger peroxisomes in rat liver. Male Sprague-Dawley rats were given PFOA (150 mg/kg body weight) or vehicle. Animals were sacrificed at different times following PFOA administration, and 3 h after the induction of autophagy with the antilipolytic agent 3,5-dimethyl pyrazole (DMP, 12 mg/kg body weight). The levels of ACOX and UOX activity were measured in the liver tissue. Results showed that autophagy caused a parallel, significant decrease in both enzymes activity in control rats, and that in PFOA-treated rats the effects were different and changed with PFOA time administration. Changes are compatible with the hypothesis that newly formed ACOX-rich peroxisomes are resistant to pexophagy and that sensitivity to pexophagy increases with increasing peroxisomal "age." In conclusion, there is indirect evidence supporting the hypothesis that autophagy may recognize and degrade older peroxisomes.


Subject(s)
Autophagy , Liver/metabolism , Mitochondria, Liver/metabolism , Peroxisomes/metabolism , Animals , Caprylates/pharmacology , Fluorocarbons/pharmacology , Male , Oxidoreductases/metabolism , Rats , Rats, Sprague-Dawley
2.
Lipids ; 51(4): 477-86, 2016 Apr.
Article in English | MEDLINE | ID: mdl-26968401

ABSTRACT

Dolichol, an end product of the mevalonate pathway, has been proposed as a biomarker of aging, but its biological role, not to mention its catabolism, has not been fully understood. UV-B radiation was used to induce oxidative stress in isolated rat hepatocytes by the collagenase method. Effects on dolichol, phospholipid-bound polyunsaturated fatty acids (PL-PUFA) and known lipid soluble antioxidants [coenzyme Q (CoQ) and α-tocopherol] were studied. The increase in oxidative stress was detected by a probe sensitive to reactive oxygen species (ROS). Peroxidation of lipids was assessed by measuring the release of thiobarbituric acid reactive substances (TBARS). Dolichol, CoQ, and α-tocopherol were assessed by high-pressure liquid chromatography (HPLC), PL-PUFA by gas-liquid chromatography (GC). UV-B radiation caused an immediate increase in ROS as well as lipid peroxidation and a simultaneous decrease in the levels of dolichol and lipid soluble antioxidants. Decrease in dolichol paralleled changes in CoQ levels and was smaller to that in α-tocopherol. The addition of mevinolin, a competitive inhibitor of the enzyme 3-hydroxy-3-methylglutaryl CoA reductase (HMG-CoAR), magnified the loss of dolichol and was associated with an increase in TBARS production. Changes in PL-PUFA were minor. These findings highlight that oxidative stress has very early and similar effects on dolichol and lipid soluble antioxidants. Lower levels of dolichol are associated with enhanced peroxidation of lipids, which suggest that dolichol may have a protective role in the antioxidant machinery of cell membranes and perhaps be a key to understanding some adverse effects of statin therapy.


Subject(s)
Antioxidants/analysis , Dolichols/analysis , Hepatocytes/radiation effects , Ultraviolet Rays/adverse effects , Aging/metabolism , Animals , Cells, Cultured , Chromatography, Liquid/methods , Hepatocytes/cytology , Lipid Peroxidation/radiation effects , Male , Rats , Reactive Oxygen Species/metabolism
3.
Mini Rev Med Chem ; 14(7): 551-6, 2014.
Article in English | MEDLINE | ID: mdl-24958217

ABSTRACT

Aging has been defined as a gradually decreasing ability to maintain homeostasis and increasing risk to die. Growing evidence supports malfunctioning with age of quality control system. At an older age, accumulation of altered macromolecules and membranes may impair cell functioning; accumulation of altered mitochondria and peroxisomes may boost the yield of ROS per unit of produced energy and accelerate the aging process. Evidence produced that autophagy, an essential part in cell housekeeping during fasting, may help removal of altered membranes, mitochondria and peroxisomes selectively and account for the antiaging effects of caloric restriction. Stimulation of autophagy may improve innate and adaptive immunity; decrease the risk of myopathy, heart disease, liver disease, neurodegeneration and cancer; and retard aging. Functioning of autophagy may decline in well fed adults and is almost negligible at older age. Induction of autophagy may result in "cleaner cells" lower in oxidative status and more resistant to injury and disease. The administration of antilipolytic drugs to fasted animals was shown to intensify autophagy in a physiologically appropriate manner, to enhance submaximal antiaging effects of low level of caloric restriction, to rapidly rescue older cells from the accumulation of altered mtDNA and older peroxisomes, to increase urinary 8-OHdG levels, and counteract the age-related hypercholesterolemia in rodents. In conclusion, benefits of long-lasting stimulation of autophagy and protein and organelle turnover shows that antilipolytic drugs might find a novel therapeutic application in antiaging medicine.


Subject(s)
Aging/drug effects , Antimetabolites/pharmacology , Lipolysis/drug effects , Pyrazoles/pharmacology , Autophagy/drug effects , Caloric Restriction , Humans
4.
Aging Clin Exp Res ; 26(1): 13-8, 2014 Feb.
Article in English | MEDLINE | ID: mdl-23982787

ABSTRACT

Autophagy, a health-promoting lysosomal degradation pathway that controls the quality of the cytoplasm by eliminating protein aggregates and damaged organelles including 8-OHdG-rich mitochondria, is under investigation as a target for prevention and/or treatment of several human diseases and decelerating aging. Stimulation of autophagy was shown to rescue older liver cells from accumulation of 8-OHdG-rich mitochondria and to increase urinary 8-OHdG levels. Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) is a recently recommended biomarker for monitoring oxidative status over time. In order to rule out the possibility that the in vivo stimulation of autophagy may cause an increase in the oxidative status, in this study we compared the effects of the stimulation of autophagy by two different procedures (the administration of antilipolytic drug and everolimus, an mTOR inhibitor in clinical use) on the urinary levels of 8-OHdG and 15-isoprostane F2t, another well-known biomarker of the oxidative status. Results show that both procedures increased the urinary 8-OHdG levels without any change in urinary 15-isoprostane F2t; this increase in urinary 8-OHdG levels after the antilipolytic drug was fully suppressed by the simultaneous injection of glucose to make rats transiently incompetent for the endocrine stimulation of autophagy. Conclusions are that the in vivo stimulation of autophagy does not affect the oxidative status and that the increasing effect on urinary 8-OHdG may be secondary to an increased degradation of previously accumulated 8-OHdG-rich (mt)DNA. The authors are aware that findings may open the way to a safe, easy, highly desirable non-invasive test for successful in vivo activation of autophagy after pharmacological stimulation.


Subject(s)
Autophagy/physiology , Oxidative Stress/physiology , 8-Hydroxy-2'-Deoxyguanosine , Animals , Autophagy/drug effects , Biomarkers/urine , Deoxyguanosine/analogs & derivatives , Deoxyguanosine/urine , Dinoprost/analogs & derivatives , Glucose/pharmacology , Isoprostanes/urine , Male , Oxidative Stress/drug effects , Rats , Rats, Sprague-Dawley
5.
Age (Dordr) ; 35(2): 261-70, 2013 Apr.
Article in English | MEDLINE | ID: mdl-22351421

ABSTRACT

8-Hydroxy-2-deoxyguanosine (8OHdG) excreted into the urine is considered a marker of oxidative stress effect on DNA, and it is reported to be mainly produced by the DNA repair system. In previous works, we showed that autophagy was also involved in 8OHdG disposal through the degradation of oxidatively altered mitochondria. Here, we show that aging in Sprague-Dawley male rats is associated with a decline in the in vitro function of liver autophagy and a slight and not significant decrease in the urinary excretion of 8OHdG. In addition, we demonstrate that anti-aging caloric restriction maintains levels of both liver autophagy and urinary excretion of 8OHdG at very high levels throughout life. Finally, we show the in vivo stimulation of autophagy by the administration of an antilipolytic agent or everolimus, which rescues rats from the accumulation of 8OHdG in the liver mtDNA, also causes a dramatic increase in the urinary excretion of 8OHdG. The intensification of autophagy by the administration of the antilipolytic drugs to fasting rats faded progressively with increasing age, together with a reduced increase in 8OHdG output into the urine. It is concluded that the process of autophagy may play a major role in the disposal of 8OHdG with urine, and that the assay of 8OHdG levels in the urine before and after the stimulation of autophagy may provide a novel, non-invasive and safe procedure to monitor the in vivo functioning of the process.


Subject(s)
Aging/metabolism , Autophagy/physiology , Caloric Restriction , Deoxyguanosine/analogs & derivatives , Liver/metabolism , 8-Hydroxy-2'-Deoxyguanosine , Analysis of Variance , Animals , Deoxyguanosine/urine , Everolimus , Hypolipidemic Agents/pharmacology , Male , Oxidative Stress , Rats , Rats, Sprague-Dawley , Sirolimus/analogs & derivatives , Sirolimus/pharmacology
6.
Mech Ageing Dev ; 132(6-7): 305-14, 2011.
Article in English | MEDLINE | ID: mdl-21741396

ABSTRACT

The age-related increased impedance in large arteries overloads the senescent heart, and the myocardial phenotype is hypertrophic. Together with qualitative changes observed in the senile heart, this can be responsible for impaired diastolic function. A restricted diet providing adequate nutrient intake, e.g. alternate-day fasting (ADF), has been shown to extend life-span and decrease incidence and progression of age-associated diseases in laboratory rodents, and to ameliorate some metabolic markers of aging in rhesus monkeys and humans. This study reports an age-related increase of some biological and morphological hypertrophy markers in the rat heart, together with increased plasma BNP, a well known marker of heart failure. The tissue modifications might likely be related to hyper-activation of two of the signaling pathways associated with myocardial pathological hypertrophy: ERK1/2 and PI3Kγ. Increased ERK1/2 activation might be in part related to the disturbance of STAT3, with a consequent decrease of SOCS3. In this context, the down-modulation of ERK1/2 and PI3Kγ signaling, together with the restoration of STAT3 activity and SOCS3 content, both observed with ADF, might help to reduce pathological hypertrophy stimuli and to rescue an important cardioprotective pathway, possibly opening new preventive and therapeutic perspectives in age-related heart failure.


Subject(s)
Cardiomegaly/metabolism , Fasting/metabolism , Longevity , MAP Kinase Signaling System , Mitogen-Activated Protein Kinase 3/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Animals , Biomarkers/metabolism , Cardiomegaly/pathology , Male , Rats , Rats, Sprague-Dawley , STAT3 Transcription Factor/metabolism , Suppressor of Cytokine Signaling 3 Protein , Suppressor of Cytokine Signaling Proteins/metabolism
7.
Free Radic Biol Med ; 48(1): 47-54, 2010 Jan 01.
Article in English | MEDLINE | ID: mdl-19818847

ABSTRACT

The free radical theory of aging is currently one of the most popular. In parallel, many studies have demonstrated the association of fibrosis and increased oxidative stress in the pathogenesis of some chronic human diseases, and fibrosis is often characteristic of aging tissues. One of the few interventions that effectively slow aging is calorie restriction and the protection against the age-associated increase of oxidative stress remains one of the foremost hypotheses to explain this action. As an alternative to traditional calorie restriction, another dietary regimen, termed alternate-day fasting, has also been tested, whose antiaging mechanisms have not been explored so much extensively. We thus studied the effects of alternate-day fasting, started at 2 months of age, on oxidative stress and fibrosis in the heart during aging. In the left ventricle of the heart of elderly (aged 24 months) versus young (aged 6 months) male rats we found a significant increase in oxidative stress paralleled by increased fibrosis. In parallel there was a significant increase in inflammatory cytokine levels and in NF-kB DNA binding activity with advancing age. Alternate-day fasting protected against all these age-related phenomena. These data support the hypothesis that this kind of dietary restriction protects against age-related fibrosis, at least in part by reducing inflammation and oxidative damage, and this protection can thus be considered a factor in the prevention of age-related diseases with sclerotic evolution.


Subject(s)
Aging/physiology , Fasting/physiology , Heart , Myocardium/metabolism , Myocardium/pathology , NF-kappa B/antagonists & inhibitors , Oxidative Stress , Animals , Cytokines/immunology , Fibrosis/prevention & control , Inflammation/prevention & control , Male , NF-kappa B/metabolism , Oxidation-Reduction , Rats , Rats, Sprague-Dawley
8.
Rejuvenation Res ; 12(2): 77-84, 2009 Apr.
Article in English | MEDLINE | ID: mdl-19419245

ABSTRACT

Aging is characterized by several metabolic changes responsible for the decline of certain functions and the appearance of age-related diseases, including hypercholesterolemia, which is the main risk factor for atherosclerosis and cardiovascular disease. Similar changes in a number of morphological and biochemical parameters were observed in rats. Caloric restriction (CR) was shown to increase longevity and prevent age-related diseases in various organisms, and to counteract the age-associated increase in plasma cholesterol. CR was thought to operate through the stimulation of the process of macroautophagy. The aim of this work was to investigate the effect of the stimulation of macroautophagy on age-associated cholesterolemia. Mature Sprague-Dawley rats were fasted overnight and given the antilipolytic agent 3,5-dimethylpyrazole (DMP; 12 mg/kg b.w. in 0.2 mL of saline, intraperitoneally). The age-related changes in cholesterol plasma level, 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA-R) activity, and lipoperoxidation were determined. Low-density lipoprotein (LDL) receptor expression was determined by immunoblot of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE)-separated liver membranes. Results show that the stimulation of macroautophagy reduces the total LDL and high-density lipoprotein (HDL) cholesterol plasma level to juvenile values, and triglycerides levels even lower. The hypocholesterolemic action of DMP requires neither the counteraction of the age-related changes in the HMG-CoA-R activation state and regulation, nor the counteraction of the age-related increase in lipoperoxidation, and only involves a restoration of the numbers of LDL receptors on liver membranes to juvenile levels.


Subject(s)
Aging/drug effects , Aging/pathology , Autophagy/drug effects , Hypercholesterolemia/prevention & control , Lipolysis/drug effects , Pyrazoles/pharmacology , Aging/blood , Amino Acids, Branched-Chain/blood , Animals , Cell Extracts , Enzyme Activation/drug effects , Hydroxymethylglutaryl CoA Reductases/metabolism , Hypercholesterolemia/blood , Hypercholesterolemia/enzymology , Injections, Intraperitoneal , Lipids/blood , Liver/drug effects , Liver/enzymology , Male , Phosphorylation/drug effects , Pyrazoles/administration & dosage , Rats , Rats, Sprague-Dawley , Reactive Oxygen Species/metabolism , Receptors, LDL/metabolism , Time Factors
9.
Methods Enzymol ; 452: 441-55, 2009.
Article in English | MEDLINE | ID: mdl-19200897

ABSTRACT

The functioning of macroautophagy declines with increasing age in the liver of ad libitum fed animals, whereas it is preserved in rats submitted to antiaging caloric restriction. In this perspective, monitoring autophagy during aging may provide a useful biomarker of aging. Here we describe a procedure for the quantification of the ex vivo functioning of autophagy by the use of single-pass liver perfusion to measure the rate of degradation of prelabeled long-lived proteins. The maximum rate of autophagy can be measured after the pharmacological suppression of the supply of free fatty acids during fasting, which intensifies the activation of autophagy by a physiological mechanism. The effects of treatment on the plasma level of branched chain amino acids may be used as a minimally invasive indicator of the intensification of autophagy. The effects of aging on autophagic proteolysis and on amino acid and hormone control can also be assessed by measuring the rate of the 3-methyladenine-sensitive valine released from isolated liver cells incubated in vitro.


Subject(s)
Aging/physiology , Autophagy/physiology , Caloric Restriction , Liver/metabolism , Animals , Hepatocytes/metabolism , Rats , Rats, Inbred F344 , Rats, Sprague-Dawley , Rats, Wistar
10.
Mech Ageing Dev ; 129(12): 759-62, 2008 Dec.
Article in English | MEDLINE | ID: mdl-18929595

ABSTRACT

Levels of plasma cholesterol, particularly LDL cholesterol, increase with increasing age in humans and rodents. Feeding a fish oil-rich diet may exert hypocholesterolemic effects. The aim of this work was to examine the effects of a life-long administration of a PUFA-enriched diet and of a PUFA-deficient diet in male Sprague-Dawley rats on the age-associated increases in plasma cholesterol and triglycerides. Diet had small effects on body-weight, and had dramatic effects on liver phospholipids-fatty acids. Surprisingly, both diets counteracted the age-associated changes in plasma cholesterol and triglycerides similarly and benefits were already visible in adult rats.


Subject(s)
Aging/blood , Cholesterol/blood , Dietary Fats, Unsaturated/administration & dosage , Fatty Acids, Unsaturated/administration & dosage , Animals , Fatty Acids/chemistry , Fatty Acids/metabolism , Liver/metabolism , Male , Phospholipids/chemistry , Phospholipids/metabolism , Rats , Rats, Sprague-Dawley , Triglycerides/blood
11.
Mech Ageing Dev ; 129(12): 722-7, 2008 Dec.
Article in English | MEDLINE | ID: mdl-18930075

ABSTRACT

Intracellular concentration of cholesterol is regulated by the balance between endogenous synthesis and exogenous uptake; endogenous synthesis is subject to feedback control of hepatic 3-hydroxy-3-methyl-glutaryl-CoA reductase activity, while the exogenous supply is mainly controlled by the modulation of the low-density lipoprotein receptor. During ageing, hepatic lipid modifications occur and caloric restriction are able to prevent these changes. So, the aim of this work was to evaluate the mechanisms underlying the effect exerted both by caloric restrictions and by a diet enriched with Omega-3 fatty acids, on the cholesterol plasma levels during ageing, by studying the regulation of the protein involved in cholesterol homeostasis maintenance. Livers from diet restricted and Omega-3 supplemented diet fed 24-month-old rat were used to analyze, the protein complex of cholesterol homeostasis maintenance and those ones that are able to modulate 3-hydroxy-3-methyl-glutaryl-CoA reductase. The data obtained demonstrate that both caloric restriction and Omega-3 supplemented diets are able to prevent hypercholesterolemia, by regulating HMG-CoAR activation state by controlling ROS production and p38 phosphorylation. Moreover also the age-dependent loss of LDLr membrane exposition is prevented.


Subject(s)
Aging/metabolism , Caloric Restriction , Cholesterol/metabolism , Fatty Acids, Omega-3/administration & dosage , AMP-Activated Protein Kinases/metabolism , Aging/blood , Animals , Cholesterol/biosynthesis , Cholesterol/blood , Hydroxymethylglutaryl CoA Reductases/metabolism , Hypercholesterolemia/metabolism , Hypercholesterolemia/prevention & control , Liver/metabolism , Male , Rats , Rats, Sprague-Dawley , Reactive Oxygen Species/metabolism , Receptors, LDL/metabolism , p38 Mitogen-Activated Protein Kinases/metabolism
12.
J Gerontol A Biol Sci Med Sci ; 63(6): 550-5, 2008 Jun.
Article in English | MEDLINE | ID: mdl-18559627

ABSTRACT

Autophagy is a process that sequesters and degrades altered organelles and macromolecular cytoplasmic constituents for cellular restructuring and repair, and as a source of nutrients for metabolic use in early starvation it may be involved in anti-aging mechanisms of caloric restriction. The effects of 40% daily dietary restriction (DR) and intermittent feeding (EOD) on the age-related changes in the endocrine regulation of autophagic proteolysis were studied by monitoring the rate of valine release from isolated rat liver cells. Results show that in ad libitum-fed rats sensitivity of autophagy to glucagon and insulin declines by one order of magnitude in older rats. Both DR and EOD maintain the sensitivity to glucagon at juvenile levels, whereas only EOD can fully maintain response to insulin. It is concluded that changes in the sensitivity to glucagon may have a role in the aging process.


Subject(s)
Aging/physiology , Autophagy/physiology , Caloric Restriction , Liver/metabolism , Animals , Glucagon/physiology , Insulin/physiology , Male , Rats , Rats, Sprague-Dawley , Valine/metabolism
13.
Biochem Biophys Res Commun ; 366(3): 786-92, 2008 Feb 15.
Article in English | MEDLINE | ID: mdl-18082617

ABSTRACT

Autophagy is an intracellular pathway induced by starvation, inhibited by nutrients, that is responsible for degradation of long-lived proteins and altered cell organelles. This process is involved in cell maintenance could be induced by antilipolytic drugs and may have anti-aging effects [A. Donati, The involvement of macroautophagy in aging and anti-aging interventions, Mol. Aspects Med. 27 (2006) 455-470]. We analyzed the effect of an intraperitoneal injection of an antilipolytic agent (3,5'-dimethylpyrazole, DMP, 12mg/kg b.w.), that mimics nutrient shortage on autophagy and expression of autophagic genes in the liver of male 3-month-old Sprague-Dawley albino rats. Autophagy was evaluated by observing electron micrographs of the liver autophagosomal compartment and by monitoring protein degradation assessed by the release of valine into the bloodstream. LC3 gene expression, whose product is one of the best known markers of autophagy, was also monitored. As expected, DMP decreased the plasma levels of free fatty acids, glucose, and insulin and increased autophagic vacuoles and proteolysis. DMP treatment caused an increase in the expression of the LC3 gene although this occurred later than the induction of authophagic proteolysis caused by DMP. Glucose treatment rescued the effects caused by DMP on glucose and insulin plasma levels and negatively affected the rate of autophagic proteolysis, but did not suppress the positive regulatory effect on LC3 mRNA levels. In conclusion, antilipolytic drugs may induce both autophagic proteolysis and higher expression of an autophagy-related gene and the effect on autophagy gene expression might not be secondary to the stimulation of autophagic proteolysis.


Subject(s)
Autophagy/physiology , Gene Expression Regulation/physiology , Hypolipidemic Agents/administration & dosage , Liver/metabolism , Proteome/metabolism , Pyrazoles/administration & dosage , Animals , Autophagy/drug effects , Dose-Response Relationship, Drug , Gene Expression Regulation/drug effects , Liver/drug effects , Male , Rats , Rats, Sprague-Dawley
14.
Biogerontology ; 9(1): 1-10, 2008 Feb.
Article in English | MEDLINE | ID: mdl-17902036

ABSTRACT

Proteasome activity is known to decrease with aging in ad libitum (AL) fed rats. Severe caloric restriction (CR) significantly extends the maximum life-span of rats, and counteracts the age-associated decrease in liver proteasome activities. Since few investigations have explored whether lower CR diets might positively counteract the age associated decrease in proteasome activity, we then investigated the effects of a mild CR regimen on animal life-span, proteasome content and function. In addition, we addressed the question whether both CR regimens might also affect the expression of Hsc70 protein, a constitutive chaperone reported to share a role in the function of proteasome complex and in the repair of proteotoxic damage, and whose level decreased during aging. In contrast to severe CR, mild CR had a poor effect on life-span; however, it better counteracted the decrease of proteasome activities. Both regimens, however, maintain Hsc70 in liver of old rats at level comparable to that of young rats. Interestingly, the effects of aging and CRs on liver proteasome enzyme activities did not appear to be associated with parallel changes in the amount of proteasome proteins suggesting that the quality (molecular activity of the enzymes) rather than the quantity are likely to be modified with age. In conclusion, the results presented in this work show that a mild CR can have beneficial effects on liver function of aging rats because is adequate to counteract the decrease of proteasome function and Hsc70 chaperone level.


Subject(s)
Aging/metabolism , Caloric Restriction , HSC70 Heat-Shock Proteins/metabolism , Proteasome Endopeptidase Complex/metabolism , Animals , Blotting, Western , Male , Rats , Rats, Sprague-Dawley
15.
Curr Aging Sci ; 1(1): 4-9, 2008 Mar.
Article in English | MEDLINE | ID: mdl-20021367

ABSTRACT

Accumulation of oxidatively altered cell components may play a role in the age-related cell deterioration and associated diseases. Caloric restriction is the most robust anti-aging intervention that extends lifespan and retards the appearance of age-associated diseases. Autophagy is a highly conserved cell-repair process in which the cytoplasm, including excess or aberrant organelles, is sequestered into double-membrane vesicles and delivered to the degradative vacuoles. Autophagy has an essential role in adaptation to fasting and changing environmental conditions. Several pieces of evidence show that autophagy may be an essential part in the anti-aging mechanism of caloric restriction: 1. The function of autophagy declines with increasing age; 2. The temporal pattern of the decline parallels the changes in biomarkers of membrane aging and in amino acid and hormone signalling. 3. These age-dependent changes in autophagy are prevented by calorie restriction. 4. The prevention of the changes in autophagy and biomarkers of aging co-varies with the effects of calorie restriction on life-span. 5. A long-lasting inhibition of autophagy accelerates the process of aging. 6. A long-lasting stimulation of autophagy retards the process of aging in rats. 7. Stimulation of autophagy may rescue older cells from accumulation of altered mtDNA. 8. Stimulation of autophagy counteracts the age-related hypercholesterolemia in rodents. It is suggested that the pharmacological intensification of suppression of aging (P.I.S.A. treatment) by the stimulation of autophagy might prove to be a big step towards retardation of aging and prevention of age-associated diseases in humans.


Subject(s)
Aging/physiology , Autophagy , Caloric Restriction , Cellular Senescence , Aging/genetics , Aging/metabolism , Animals , Autophagy/drug effects , Autophagy/genetics , Biomarkers/metabolism , Cellular Senescence/drug effects , Cellular Senescence/genetics , DNA, Mitochondrial/metabolism , Evidence-Based Medicine , Humans , Lipolysis/drug effects , Longevity , Oxidative Stress , Rats
16.
Ann N Y Acad Sci ; 1114: 69-78, 2007 Oct.
Article in English | MEDLINE | ID: mdl-17934054

ABSTRACT

Aging denotes a postmaturational deterioration of cells and organisms with the passage of time, an increased vulnerability to challenges and prevalence of age-associated diseases, and a decreased ability to survive. Causes of this deterioration may be found in an enhanced production of reactive oxygen species (ROS) and oxidative damage and incomplete "housekeeping." Caloric restriction is the most robust anti-aging intervention known so far. Similar beneficial effects on median and maximum life span were obtained by feeding animals a 40%-reduced diet or by every-other-day ad libitum feeding. In both instances, animals are forced to spend a great part of their time in a state of fasting and activated autophagy. Autophagy is a highly conserved process in eukaryotes, in which the cytoplasm, including excess or aberrant organelles, is sequestered into double-membrane vesicles and delivered to the lysosome/vacuole, for breakdown and eventual recycling of the resulting macromolecules. This process has an essential role in adaptation to fasting and changing environmental conditions, cellular remodeling during development, and accumulation of altered ROS-hypergenerating organelles in older cells. Several pieces of evidence show that autophagy is involved in aging and is an essential part of the anti-aging mechanism of caloric restriction. As an application, intensification of autophagy by the administration of an antilipolytic drug rescued older cells from accumulation of altered mtDNA in less than 6 hours. It is concluded that the pharmacologic intensification of autophagy (PISA treatment) has anti-aging effects and might prove to be a big step toward retardation of aging and prevention of age-associated diseases in humans.


Subject(s)
Autophagy/physiology , Caloric Restriction , Cellular Senescence/physiology , Longevity/physiology , Animals , Humans
17.
Free Radic Res ; 41(11): 1283-8, 2007 Nov.
Article in English | MEDLINE | ID: mdl-17957544

ABSTRACT

Dolichol, a long-chain polyisoprenoid broadly distributed in all tissues and cellular membranes with unknown function(s), might have a role in free radical metabolism [it accumulates in older tissues and decreases after CCl4 (in liver) or phenylhydrazine (in spleen and liver) administration]. The effects of the NADPH-ADP-Fe system on Dolichol levels in isolated hepatocytes were explored and the time-course of changes was compared with the release of MDA in the incubation medium and the decrease in CoQ 9 and 10 and Vitamin E levels. Results showed that the system increased lipid peroxidation and decreased Dolichol and CoQ levels in-parallel fashions and lowered Vitamin E levels with shorter latency. Meanwhile, no increase in dead cells and no Dolichol release in the medium were detected. In conclusion, an increase in oxidative stress possibly caused a rapid degradation of dolichol by the same (unknown) mechanism responsible for the breakdown of Ubiquinone isoprenoid chains.


Subject(s)
Dolichols/metabolism , Hepatocytes/metabolism , Oxidative Stress/physiology , Animals , Cells, Cultured , Male , Malondialdehyde/metabolism , Models, Biological , Peroxides/pharmacology , Rats , Rats, Sprague-Dawley , Ubiquinone/metabolism , Vitamin E/metabolism
18.
J Cell Biochem ; 101(1): 235-43, 2007 May 01.
Article in English | MEDLINE | ID: mdl-17203467

ABSTRACT

Ageing has been defined as a progressive decrease in physiological capacity and a reduced ability to respond to environmental stresses. It has been observed that diet-restricted animals show a minor morbidity in age-related disease. Among these age-related diseases, hypercholesterolemia is the most recurring one and it is often associated with cardiac failure. Several studies have been published indicating age-dependent changes in circulating levels of cholesterol in both humans and in rodents; recently changes have also been reported in the proteins involved in cholesterol homeostasis, that is, 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoAR), Insig-induced gene (Insig) protein, SREBP cleavage activating protein (SCAP), sterol regulatory element binding protein (SREBP), and low density lipoprotein receptor (LDLr). Most age-related modifications of biochemical parameters are normalized or very improved in food-restricted animals, so the aim of this work is to examine whether or not alterations of the factors involved in cholesterol homeostasis which occur during ageing could be counteracted by caloric restriction (CR). The data show that the diet restrictions used attenuate the age-related effects on the factors involved in the synthesis and the degradation rate of HMG-CoAR; in spite of this, CRs have a good effect on the age-related hypercholesterolemia whose reduction seems to depend both on the correct membrane LDLr localization and on the proper restored HMG-CoAR activity.


Subject(s)
Aging/physiology , Caloric Restriction , Hydroxymethylglutaryl CoA Reductases/metabolism , Hypercholesterolemia/metabolism , Intracellular Signaling Peptides and Proteins/metabolism , Membrane Proteins/metabolism , Receptors, LDL/metabolism , Animals , Cholesterol/blood , Gene Expression Regulation , Hydroxymethylglutaryl CoA Reductases/genetics , Hypercholesterolemia/genetics , Intracellular Signaling Peptides and Proteins/genetics , Liver/metabolism , Male , Membrane Proteins/genetics , Random Allocation , Rats , Rats, Sprague-Dawley , Receptors, LDL/genetics
19.
Autophagy ; 3(1): 26-7, 2007.
Article in English | MEDLINE | ID: mdl-16963838

ABSTRACT

Autophagy is a major intracellular degradation/recycling system ubiquitous in eukaryotic cells. It contributes to the turnover of cellular components by delivering portions of the cytoplasm and organelles to lysosomes, where they are digested. Starvation-induced autophagy is required for maintaining an amino acid pool for gluconeogenesis and for the synthesis of proteins essential to survival under starvation conditions. In addition, autophagy plays an important role in the degradation of excess or injured organelles, including mitochondria. To test the hypothesis of an involvement of a decrease in autophagy in the process of aging, we explored the antiaging effects of pharmacological stimulation of autophagy on the age-dependent accumulation of 8-OHdG-rich mitochondria in rat liver. Male 3-month and 16-month-old 24 hours-fasted Sprague Dawley rats were injected with the antilipolytic agent [3,5-dimethylpyrazole (DMP)] intraperitoneally. Results showed that drug injection rescued older cells from the accumulation of 8-OHdG in the mtDNA in less than 6 hours, but no significant decrease in the level of cytochrome c oxidase activity was observed. Together, these data provide indirect evidence that 8-OHdG might accumulate in a small pool of mitochondria with increasing age rather than be degraded by the autophagic machinery selectively.


Subject(s)
Aging/physiology , Autophagy/physiology , Mitochondria/physiology , 8-Hydroxy-2'-Deoxyguanosine , Animals , Caloric Restriction , Cytochromes c/metabolism , DNA, Mitochondrial/metabolism , Deoxyguanosine/analogs & derivatives , Deoxyguanosine/analysis , Male , Mitochondria/chemistry , Pyrazoles/pharmacology , Rats , Rats, Sprague-Dawley
20.
Mol Aspects Med ; 27(5-6): 455-70, 2006.
Article in English | MEDLINE | ID: mdl-16973209

ABSTRACT

Macroautophagy is a process that sequesters and degrades organelles and macromolecular constituents of cytoplasm for cellular restructuring and repair, and as a source of nutrients for metabolic use in early starvation. Extensive evidence has been reported that macroautophagy process declines with increasing age. This impairment, probably due to ad libitum feeding, may cause accumulation of altered structures leading to the age-related decline in cell functions. It has been suggested that caloric restriction (CR) and disruption of insulin-like signals contrast the process of aging by prolonged stimulation of macroautophagy. According to this hypothesis, it is shown that life-long weekly administration of an anti-lipolytic drug decreases glucose and insulin levels, stimulates autophagy and intensifies anti-aging effects of submaximal CR.


Subject(s)
Aging/physiology , Autophagy , Cellular Senescence/physiology , Aging/drug effects , Animals , Caloric Restriction , Cellular Senescence/drug effects , Humans , Insulin/metabolism , Signal Transduction
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