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Calorie restriction in rodents: Caveats to consider. Ageing Res Rev 2017; 39:15-28. [PMID: 28610949 DOI: 10.1016/j.arr.2017.05.008] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 05/30/2017] [Accepted: 05/31/2017] [Indexed: 02/08/2023]
Abstract
The calorie restriction paradigm has provided one of the most widely used and most useful tools for investigating mechanisms of aging and longevity. By far, rodent models have been employed most often in these endeavors. Over decades of investigation, claims have been made that the paradigm produces the most robust demonstration that aging is malleable. In the current review of the rodent literature, we present arguments that question the robustness of the paradigm to increase lifespan and healthspan. Specifically, there are several questions to consider as follows: (1) At what age does CR no longer produce benefits? (2) Does CR attenuate cognitive decline? (3) Are there negative effects of CR, including effects on bone health, wound healing, and response to infection? (4) How important is schedule of feeding? (5) How long does CR need to be imposed to be effective? (6) How do genotype and gender influence CR? (7) What role does dietary composition play? Consideration of these questions produce many caveats that should guide future investigations to move the field forward.
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Brewer RA, Gibbs VK, Smith DL. Targeting glucose metabolism for healthy aging. NUTRITION AND HEALTHY AGING 2016; 4:31-46. [PMID: 28035340 PMCID: PMC5166514 DOI: 10.3233/nha-160007] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Advancing age is the greatest single risk factor for numerous chronic diseases. Thus, the ability to target the aging process can facilitate improved healthspan and potentially lifespan. Lack of adequate glucoregulatory control remains a recurrent theme accompanying aging and chronic disease, while numerous longevity interventions result in maintenance of glucoregulatory control. In this review, we propose targeting glucose metabolism to enhance regulatory control as a means to ameliorate the aging process. We highlight that calorie restriction improves glucoregulatory control and extends both lifespan and healthspan in model organisms, but we also indicate more practical interventions (i.e., calorie restriction mimetics) are desirable for clinical application in humans. Of the calorie restriction mimetics being investigated, we focus on the type 2 diabetes drug acarbose, an α-glucosidase inhibitor that when taken with a meal, results in reduced enzymatic degradation and absorption of glucose from complex carbohydrates. We discuss alternatives to acarbose that yield similar physiologic effects and describe dietary sources (e.g., sweet potatoes, legumes, and berries) of bioactive compounds with α-glucosidase inhibitory activity. We indicate future research should include exploration of how non-caloric compounds like α-glucosidase inhibitors modify macronutrient metabolism prior to disease onset, which may guide nutritional/lifestyle interventions to support health and reduce age-related disease risk.
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Affiliation(s)
- Rachel A. Brewer
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Victoria K. Gibbs
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, USA
- Nutrition Obesity Research Center, Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, USA
- Comprehensive Center for Healthy Aging, University of Alabama at Birmingham, Birmingham, AL, USA
- Nathan Shock Center of Excellence in the Biology of Aging, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Daniel L. Smith
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, USA
- Nutrition Obesity Research Center, Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, USA
- Comprehensive Center for Healthy Aging, University of Alabama at Birmingham, Birmingham, AL, USA
- Nathan Shock Center of Excellence in the Biology of Aging, University of Alabama at Birmingham, Birmingham, AL, USA
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Kim SS, Choi KM, Kim S, Park T, Cho IC, Lee JW, Lee CK. Whole-transcriptome analysis of mouse adipose tissue in response to short-term caloric restriction. Mol Genet Genomics 2016; 291:831-47. [PMID: 26606930 DOI: 10.1007/s00438-015-1150-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Accepted: 11/16/2015] [Indexed: 12/22/2022]
Abstract
Caloric restriction (CR) has been shown to extend the lifespan of many species by improving cellular function and organismal health. Additionally, fat reduction by CR may play an important role in lengthening lifespan and preventing severe age-related diseases. Interestingly, CR induced the greatest transcriptome change in the epididymal fat of mice in our study. In this transcriptome analysis, we identified and categorized 446 genes that correlated with CR level. We observed down-regulation of several signaling pathways, including insulin/insulin-like growth factor 1 (insulin/IGF-1), epidermal growth factor (EGF), transforming growth factor beta (TGF-β), and canonical wingless-type mouse mammary tumor virus integration site (Wnt). Many genes related to structural features, including extracellular matrix structure, cell adhesion, and the cytoskeleton, were down-regulated, with a strong correlation to the degree of CR. Furthermore, genes related to the cell cycle and adipogenesis were down-regulated. These biological processes are well-identified targets of insulin/IGF-1, EGF, TGF-β, and Wnt signaling. In contrast, genes involved in specific metabolic processes, including the tricarboxylic acid cycle and the electron transport chain were up-regulated. We performed in silico analysis of the promoter sequences of CR-responsive genes and identified two associated transcription factors, Paired-like homeodomain 2 (Pitx2) and Paired box gene 6 (Pax6). Our results suggest that strict regulation of signaling pathways is critical for creating the optimal energy homeostasis to extend lifespan.
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Affiliation(s)
- Seung-Soo Kim
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, 136-701, Republic of Korea
| | - Kyung-Mi Choi
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, 136-701, Republic of Korea
| | - Soyoung Kim
- Department of Food and Nutrition, Yonsei University, Seoul, 120-749, Republic of Korea
| | - Taesun Park
- Department of Food and Nutrition, Yonsei University, Seoul, 120-749, Republic of Korea
| | - In-Cheol Cho
- Subtropical Animal Station, National Institute of Animal Science, Jeju, 690-150, Republic of Korea
| | - Jae-Won Lee
- Department of Statistics, Korea University, Seoul, 136-701, Republic of Korea
| | - Cheol-Koo Lee
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, 136-701, Republic of Korea.
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4
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Hou C, Bolt K, Bergman A. A general life history theory for effects of caloric restriction on health maintenance. BMC SYSTEMS BIOLOGY 2011; 5:78. [PMID: 21595962 PMCID: PMC3123202 DOI: 10.1186/1752-0509-5-78] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Accepted: 05/19/2011] [Indexed: 12/18/2022]
Abstract
Background Caloric restriction (CR) has been shown to keep organisms in a relatively youthful and healthy state compared to ad libitum fed counterparts, as well as to extend the lifespan of a diverse set of organisms. Several attempts have been made to understand the underlying mechanisms from the viewpoint of energy tradeoffs in organisms' life histories. However, most models are based on assumptions which are difficult to justify, or are endowed with free-adjusting parameters whose biological relevancy is unclear. Results In this paper, we derive a general quantitative, predictive model based on physiological data for endotherms. We test the hypothesis that an animal's state of health is correlated with biological mechanisms responsible for the maintenance of that animal's functional integrities. Such mechanisms require energy. By suppressing animals' caloric energy supply and biomass synthesis, CR alters animals' energy allocation strategies and channels additional energy to those maintenance mechanisms, therefore enhancing their performance. Our model corroborates the observation that CR's effects on health maintenance are positively correlated with the degree and duration of CR. Furthermore, our model shows that CR's effects on health maintenance are negatively correlated to the temperature drop observed in endothermic animals, and is positively correlated to animals' body masses. These predictions can be tested by further experimental research. Conclusion Our model reveals how animals will alter their energy budget when food availability is low, and offers better understanding of the tradeoffs between growth and somatic maintenance; therefore shedding new light on aging research from an energetic viewpoint.
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Affiliation(s)
- Chen Hou
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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5
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Anisimov VN, Berstein LM, Popovich IG, Zabezhinski MA, Egormin PA, Piskunova TS, Semenchenko AV, Tyndyk ML, Yurova MN, Kovalenko IG, Poroshina TE. If started early in life, metformin treatment increases life span and postpones tumors in female SHR mice. Aging (Albany NY) 2011; 3:148-57. [PMID: 21386129 PMCID: PMC3082009 DOI: 10.18632/aging.100273] [Citation(s) in RCA: 203] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Accepted: 02/20/2011] [Indexed: 02/03/2023]
Abstract
Hyperglycemia and hyperinsulinemia accelerate both aging and cancer. Antidiabetic biguanides such as metformin decrease glucose, insulin and IGF-1 level. Metformin increases lifespan and prevents cancer in mice, although its effects vary, depending on mice strain and gender. Here we showed that chronic treatment of female outbred SHR mice with metformin started at the age of 3, 9 or 15 months decreased body temperature and postponed age-related switch-off of estrous function. Surprisingly, metformin did not affect levels of serum cholesterol, triglycerides, glucose and insulin. Treatment with metformin started at the age of 3 months increased mean life span by 14% and maximum life span by 1 month. The treatment started at the age of 9 months insignificantly increased mean life span by only 6%, whereas the treatment started at the age of 15 months failed to increase life span. The mean life span of tumor-free mice was increased by 21% in 'the youngest group', by 7% in 'middle-aged group' and in contrast was reduced by 13% in 'the oldest group'. When started at the age of 3 and 9 months, metformin delayed the first tumor detection by 22% and 25%, correspondingly. Thus, in female SHR mice, metformin increased life span and postponed tumors when started at the young and middle but not at the old age. In contrast, metformin improves reproductive function when started at any age.
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Affiliation(s)
- Vladimir N Anisimov
- N.N. Petrov Research Institute of Oncology, Pesochny-2, St. Petersburg, Russia.
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Abstract
Reducing food intake to induce undernutrition but not malnutrition extends the life spans of multiple species, ranging from single-celled organisms to mammals. This increase in longevity by dietary restriction (DR) is coupled to profound beneficial effects on age-related pathology. Historically, much of the work on DR has been undertaken using rodent models, and 70 years of research has revealed much about the physiological changes DR induces. However, little is known about the genetic pathways that regulate the DR response and whether or not they are conserved between species. Elucidating these pathways may facilitate the design of targeted pharmaceutical treatments for a range of age-related pathologies. Here, we discuss how recent work in nonmammalian model organisms has revealed new insight into the genetics of DR and how the discovery of DR-specific transcription factors will advance our understanding of this phenomenon.
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Affiliation(s)
- William Mair
- The Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
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Cabelof DC, Ikeno Y, Nyska A, Busuttil RA, Anyangwe N, Vijg J, Matherly LH, Tucker JD, Wilson SH, Richardson A, Heydari AR. Haploinsufficiency in DNA polymerase beta increases cancer risk with age and alters mortality rate. Cancer Res 2006; 66:7460-5. [PMID: 16885342 DOI: 10.1158/0008-5472.can-06-1177] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study uses a base excision repair (BER)-deficient model, the DNA polymerase beta heterozygous mouse, to investigate the effect of BER deficiency on tumorigenicity and aging. Aged beta-pol(+/-) mice express 50% less beta-pol transcripts and protein (P < 0.05) than aged beta-pol(+/+) mice, showing maintenance of the heterozygous state over the life span of the mouse. This reduction in beta-pol expression was not associated with an increase in mutation rate but was associated with a 100% increase in the onset of hypoploidy. Aged beta-pol(+/-) mice exhibited a 6.7-fold increase in developing lymphoma (P < 0.01). Accordingly, 38% of beta-pol(+/-) mice exhibited lymphoid hyperplasia, whereas none of the beta-pol(+/+) exhibited this phenotype. beta-pol(+/-) mice were also more likely to develop adenocarcinoma (2.7-fold increase; P < 0.05) and more likely to develop multiple tumors, as 20% of the beta-pol(+/-) animals died bearing multiple tumors compared with only 5% of the beta-pol(+/+) animals (P < 0.05). In spite of accelerated tumor development, no gross effect of beta-pol heterozygosity was seen with respect to life span. However, the survival curves for the beta-pol(+/+) and beta-pol(+/-) mice are not identical. A maximum likelihood estimation analysis showed a modest but significant (P < 0.05) acceleration of the age-dependent mortality rate in beta-pol(+/-) mice. Thus, the beta-pol(+/-) mouse represents a model in which mortality rate and tumor development are accelerated and provides evidence supporting the role of genomic maintenance in both aging and carcinogenesis.
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Affiliation(s)
- Diane C Cabelof
- Karmanos Cancer Institute, Developmental Therapeutics Program, Wayne State University School of Medicine, 110 East Warren, Detroit, MI 48201, USA.
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Ikeno Y, Hubbard GB, Lee S, Richardson A, Strong R, Diaz V, Nelson JF. Housing density does not influence the longevity effect of calorie restriction. J Gerontol A Biol Sci Med Sci 2006; 60:1510-7. [PMID: 16424282 DOI: 10.1093/gerona/60.12.1510] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This study examined the effect of housing density on the longevity-extending and disease-delaying actions of calorie restriction (CR). Singly or multiply housed (four per cage) mice were either fed ad libitum (AL) or were on CR beginning at 2 months. All CR mice were fed 40% less food than were multiply housed AL mice. CR increased median longevity by 19%, and housing density had no effect on this increase. CR also reduced neoplastic lesions in both housing groups, but lymphoma, the most common neoplasm, was reduced more in singly than in multiply housed mice. Singly housed AL mice ate 40% more food than did multiply housed AL mice, but weighed the same and lived as long as multiply housed AL mice. These results indicate that CR can extend life span as effectively in multiply as in singly housed mice, even though housing density can differentially affect the cancer-reducing effect of CR.
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Affiliation(s)
- Yuji Ikeno
- Geriatric Research, Education and Clinical Center, South Texas Veterans Health Care Systems, San Antonio, TX, USA
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9
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Abstract
It has long been held that food restriction extends the life span of rodents and other species by decreasing caloric intake and slowing the rate of aging. Recent findings challenge these concepts. This review assesses these controversial issues. The conclusion is that caloric restriction underlies the life extension of rats, but not of Drosophila. Mortality characteristics show that food restriction slows the rate of aging of rats and, in some studies, of mice. However, in other mouse studies and in Drosophila, mortality characteristics have been interpreted as indicating that it delays the start but does not slow the rate of aging; the author believes that this interpretation is faulty. These differences in mortality responses to food restriction provide a potentially powerful tool for uncovering basic mechanisms underlying its life-prolonging action. A hypothesis is presented for use in the search for these mechanisms.
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Affiliation(s)
- Edward J Masoro
- Department of Physiology, University of Texas Health Science at San Antonio, TX, USA.
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10
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Abstract
A number of lines of evidence, including nonhuman primate and human studies, suggest that regulatory pathways similar to those invoked by caloric restriction (CR) may be involved in determining human longevity. Thus, pharmaceuticals capable of mimicking the molecular mechanisms of life- and health-span extension by CR (CR mimetics) may have application to human health. CR acts rapidly, even in late adulthood, to begin to extend life- and health-span in mice. We have linked these effects with rapid changes in the levels of specific gene transcripts in the liver and the heart. Our results are consistent with the rapid effects of caloric intake on the lifespan and/or biochemistry and physiology of Drosophila, rodents, rhesus macaques and humans. To test the hypothesis that existing pharmaceuticals can mimic the physiologic effects of CR, we evaluated the effectiveness of glucoregulatory drugs and putative cancer chemo-preventatives in reproducing the hepatic gene-expression profiles produced by long-term CR (LTCR). We found that 8 weeks of metformin treatment was superior to 8 weeks of CR at reproducing the specific changes in transcript levels produced by LTCR. Consistent with these results, metformin reduces cancer incidence in diabetic humans and ameliorates the onset and severity of metabolic syndrome. Metformin extends the mean and maximum lifespans of female transgenic HER-2/neu mice by 8% and 13.1% in comparison with control mice. Phenformin, a close chemical relative of metformin, extends lifespan and reduces tumor incidence in C3H mice. These results indicate that gene-expression biomarkers can be used to identify promising candidate CR mimetics.
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Affiliation(s)
- Stephen R Spindler
- Department of Biochemistry, University of California, Riverside, CA 92521, USA.
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11
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de Grey ADNJ. Resistance to debate on how to postpone ageing is delaying progress and costing lives. Open discussions in the biogerontology community would attract public interest and influence funding policy. EMBO Rep 2005; 6 Spec No:S49-53. [PMID: 15995663 PMCID: PMC1369265 DOI: 10.1038/sj.embor.7400399] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Merry BJ. Dietary restriction in rodents—delayed or retarded ageing? Mech Ageing Dev 2005; 126:951-9. [PMID: 15893804 DOI: 10.1016/j.mad.2005.03.015] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2004] [Revised: 12/02/2004] [Accepted: 03/15/2005] [Indexed: 11/26/2022]
Abstract
Dietary restriction (DR) feeding increases survival significantly in strains of rats and mice. There remains however, the question as to whether these two species are always responding in an identical manner to the feeding regime. Enhanced survival can be achieved either through a set-point effect, where there is a change in the elevation of the Ln age-specific mortality rate or, by a decrease in the slope of the Ln age-specific mortality rate that results in a significant increase in the time to double the rate of mortality. It is only the second response that is evidence of a slower rate of ageing. These two possible responses to DR feeding may confound attempts to identify the biochemical mechanisms underlying the effect of DR on survival. A general lack of consistency is evident in the data and this is apparent when evaluating the free radical hypothesis of ageing in this model. Further, this hypothesis as currently viewed may be too simplistic to explain the variety and complexity of the ageing phenotype. What may be more important is not oxidative macromolecular damage but the slow transition to this cellular endpoint through the slow development of oxidative stress and the role it plays in modifying cell gene expression profiles.
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Affiliation(s)
- B J Merry
- School of Biological Sciences, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK.
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13
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Masoro EJ. Overview of caloric restriction and ageing. Mech Ageing Dev 2005; 126:913-22. [PMID: 15885745 DOI: 10.1016/j.mad.2005.03.012] [Citation(s) in RCA: 698] [Impact Index Per Article: 36.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2004] [Revised: 12/06/2004] [Accepted: 03/15/2005] [Indexed: 01/21/2023]
Abstract
It has been known for some 70 years that restricting the food intake of laboratory rats extends their mean and maximum life span. In addition, such life extension has been observed over the years in many other species, including mice, hamsters, dogs, fish, invertebrate animals, and yeast. Since this life-extending action appears to be due to a restricted intake of energy, this dietary manipulation is referred to as caloric restriction (CR). CR extends life by slowing and/or delaying the ageing processes. The underlying biological mechanism responsible for the life extension is still not known, although many hypotheses have been proposed. The Growth Retardation Hypothesis, the first proposed, has been tested and found wanting. Although there is strong evidence against the Reduction of Body Fat Hypothesis, efforts have recently been made to resurrect it. While the Reduction of Metabolic Rate Hypothesis is not supported by experimental findings, it nevertheless still has advocates. Currently, the most popular concept is the Oxidative Damage Attenuation Hypothesis; the results of several studies provide support for this hypothesis, while those of other studies do not. The Altered Glucose-Insulin System Hypothesis and the Alteration of the Growth Hormone-IGF-1 Axis Hypothesis have been gaining favor, and data have emerged that link these two hypotheses as one. Thus, it may now be more appropriate to refer to them as the Attenuation of Insulin-Like Signaling Hypothesis. Finally, the Hormesis Hypothesis may provide an overarching concept that embraces several of the other hypotheses as merely specific examples of hormetic processes. For example, the Oxidative Damage Attenuation Hypothesis probably addresses only one of likely many damaging processes that underlie aging. It is proposed that low-intensity stressors, such as CR, activate ancient hormetic defense mechanisms in organisms ranging from yeast to mammals, defending them against a variety of adversities and, when long-term, retarding senescent processes.
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Affiliation(s)
- Edward J Masoro
- Barshop Center for Longevity and Aging Studies, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA.
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14
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Abstract
Restriction of food intake extends lifespan in evolutionarily diverse organisms, including mammals. Dietary restriction (DR) also delays the appearance of ageing-related damage and pathology and keeps organisms in a youthful state for longer. DR has hence been suggested to lower the rate of ageing. Analysis of mortality rates can be used to test this idea. During ageing, mortality rates in general increase, approximately exponentially. Lifespan can be extended either by a reduction in the rate of increase in mortality rate with age or a lowering of the initial rate of mortality. A reduction in the slope of a mortality trajectory has generally been taken to indicate that the rate of ageing has been lowered. Data on the effects of temperature on mortality in Drosophila are in accordance with this idea. Lowered temperature extends lifespan solely by lowering the slope of the mortality trajectory and flies with a hotter thermal history have permanently elevated death rates. In contrast, lowering of the initial rate of mortality has been taken to leave the rate of ageing unaffected. In Drosophila and in mice, but not in rats, DR extends lifespan by lowering the initial mortality rate. In Drosophila, the effect of DR is acute, and mortality rate switches rapidly between DR and control values with the corresponding changes in nutritional regime. DR in Drosophila therefore has no impact upon the rate of ageing. Possible mechanisms by which DR can both delay damage and pathology and yet act acutely to determine mortality rates are discussed. In rodents, some phenotypes associated with DR, including microarray profiles, show rapid switching with changed nutritional regime, pointing to potentially acute effects of DR in mammals.
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Affiliation(s)
- Linda Partridge
- Department of Biology, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK.
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15
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Dhahbi JM, Kim HJ, Mote PL, Beaver RJ, Spindler SR. Temporal linkage between the phenotypic and genomic responses to caloric restriction. Proc Natl Acad Sci U S A 2004; 101:5524-9. [PMID: 15044709 PMCID: PMC397416 DOI: 10.1073/pnas.0305300101] [Citation(s) in RCA: 196] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2003] [Indexed: 12/20/2022] Open
Abstract
Caloric restriction (CR), the consumption of fewer calories while avoiding malnutrition, decelerates the rate of aging and the development of age-related diseases. CR has been viewed as less effective in older animals and as acting incrementally to slow or prevent age-related changes in gene expression. Here we demonstrate that CR initiated in 19-month-old mice begins within 2 months to increase the mean time to death by 42% and increase mean and maximum lifespans by 4.7 (P = 0.000017) and 6.0 months (P = 0.000056), respectively. The rate of age-associated mortality was decreased 3.1-fold. Between the first and second breakpoints in the CR survival curve (between 21 and 31 months of age), tumors as a cause of death decreased from 80% to 67% (P = 0.012). Genome-wide microarray analysis of hepatic RNA from old control mice switched to CR for 2, 4, and 8 weeks showed a rapid and progressive shift toward the gene expression profile produced by long-term CR. This shift took place in the time frame required to induce the health and longevity effects of CR. Shifting from long-term CR to a control diet, which returns animals to the control rate of aging, reversed 90% of the gene expression effects of long-term CR within 8 weeks. These results suggest a cause-and-effect relationship between the rate of aging and the CR-associated gene expression biomarkers. Therefore, therapeutics mimicking the gene-expression biomarkers of CR may reproduce its physiological effects.
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Affiliation(s)
- Joseph M Dhahbi
- BioMarker Pharmaceuticals, Incorporated, 900 East Hamilton Avenue, Campbell, CA 95008, USA
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16
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van der Lely AJ. Hormone use and abuse: what is the difference between hormones as fountain of youth and doping in sports? J Endocrinol Invest 2003; 26:932-6. [PMID: 14964448 DOI: 10.1007/bf03345246] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
GH can induce changes in body composition that are considered to be advantageous to aging subjects especially. However, there are no results indicating that the use of GH during aging should be advocated, because of the lack of any proven efficacy for whatever parameter. Also, data indicate that calorie restriction can extend life spans by altering the rate of decline in reserve capacity as well as by reducing the cumulative exposure to GH. Moreover, animal data suggest that lower GH actions are positively correlated with longevity. The abuse of GH by sportsmen is based on the belief that it has potent anabolic effects, while it is difficult to detect the abuse. Again, this supposed efficacy cannot be supported by any scientific data.
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Affiliation(s)
- A J van der Lely
- Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands.
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17
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Takahashi R, Goto S. Effect of dietary restriction beyond middle age: accumulation of altered proteins and protein degradation. Microsc Res Tech 2002; 59:278-81. [PMID: 12424789 DOI: 10.1002/jemt.10205] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Dietary restriction (DR) from weaning or young adult stages in rodents throughout their usual life span has been shown to prolong longevity and lower or delay (or both) the occurrence of many late-onset diseases, but the effects of DR when performed at middle age or later have not been well investigated. We have studied the effect of DR initiated late in life on altered proteins and protein degradation. DR initiated in 23.5-month-old mice and continued for 2 months reduced the amount of altered proteins and shortened the half-life of proteins, including oxidatively modified ones. Furthermore, our more recent studies in rats demonstrated that DR initiated later in life (26.5 months old) restored the activities of proteasomes that have been implicated in removal of altered proteins. Thus, DR initiated even relatively late in life appears to have beneficial effects, restoring an animal's youthful condition in terms of the age-related accumulation of altered proteins.
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Affiliation(s)
- Ryoya Takahashi
- Department of Biochemistry, School of Pharmaceutical Sciences, Toho University, Chiba 274-8510, Japan.
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18
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Cavallini G, Donati A, Gori Z, Pollera M, Bergamini E. The protection of rat liver autophagic proteolysis from the age-related decline co-varies with the duration of anti-ageing food restriction. Exp Gerontol 2001; 36:497-506. [PMID: 11250121 DOI: 10.1016/s0531-5565(00)00224-2] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Restricting caloric intake (CR) well below that of ad libitum (AL) fed animals retards and/or delays many characteristics of ageing and the occurrence and progression of age-associated diseases, efficacy depending on duration. The hypothesis that the anti-ageing effect of CR might involve stimulation of the cell-repair mechanism autophagy was tested. The effects of ageing and duration of anti-ageing CR on liver autophagic proteolysis (AP) were explored in male AL Sprague-Dawley rats aged 2-, 6-, 12- and 24-months; and 24-month-old rats on a CR diet initiated at 2-, 6- and 12-month of age or initiated at age 2-months and interrupted at age 18 months. The age-related changes in the regulation of AP were studied by monitoring the rate of valine release in the incubation medium from isolated liver cells by an HPLC procedure. Results show that the maximum attainable rate and the regulation of AP decline with increasing age; that changes are prevented by anti-ageing CR initiated at young age, that the protective effects of CR change with the duration of diet. It is concluded that the data are compatible with the hypothesis that AP and improved membrane maintenance might be involved in the antiageing mechanism of CR.
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Affiliation(s)
- G Cavallini
- Dipartimento di Patologia sperimentale, Biotecnologie mediche, Infettivologia e Epidemiologia, Via Roma 55, 56126, Pisa, Italy
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Allison DB, Miller RA, Austad SN, Bouchard C, Leibel R, Klebanov S, Johnson T, Harrison DE. Genetic variability in responses to caloric restriction in animals and in regulation of metabolism and obesity in humans. J Gerontol A Biol Sci Med Sci 2001; 56 Spec No 1:55-65. [PMID: 12088213 DOI: 10.1093/gerona/56.suppl_1.55] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Panel 5 focused on genetic factors that might mediate or moderate the effects of caloric restriction (CR) on longevity. Panel members stated that currently there is limited information directly addressing these issues. Therefore, they focused attention on what studies could be done. In addition, the panel believed that certain conceptual issues merited clarification and focused attention on this issue. Human studies and studies of nonhuman model organisms were discussed. The panel found at least three reasons why it would be valuable to find genes that influence the (putative) longevity-promoting effect of CR in humans. Such knowledge would offer: (a) the ability to predict individual responses to CR; (b) increased understanding of physiological mechanisms; and (c) the potential to develop mechanism-based interventions to promote longevity or healthy aging. In addition, the panel emphasized several macro-level recommendations regarding research strategies to avoid, research strategies to emphasize, and resources needing development.
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Affiliation(s)
- D B Allison
- Obesity Research Center, St. Luke's-Roosevelt Hospital, Columbia University College of Physicians & Surgeons, New York City, NY 10025, USA.
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