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Jiang N, Cheng CJ, Liu Q, Strong R, Gelfond J, Nelson JF. Deciphering the Timing and Impact of Life-extending Drugs: A Novel Analytic Approach that Differentiates Early, Midlife, and Senescence Phase Efficacies. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.27.585737. [PMID: 38586027 PMCID: PMC10996648 DOI: 10.1101/2024.03.27.585737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Evidence that life-extending interventions are not uniformly effective across the lifespan calls for an analytic tool that can estimate age-specific treatment effects on mortality hazards. Here we report such a tool, applying it to mouse data from 42 agents tested in the NIA Interventions Testing Program. This tool identified agents that either reduced (22) or increased (16) mortality hazards or did both (6), all with marked variation in the duration of efficacy and magnitude of effect size. Only 7 reduced mortality hazards after the 90% mortality, when the burden of senescence is greatest. Sex differences were apparent in all parameters. This new analytic tool complements the commonly used log-rank test. It detects more potential life-extending candidates (22 versus 10) and indicates when during the life course they are effective. It also uncovers adverse effects. Most importantly, it identifies agents that specifically reduce mortality hazards during the senescent phase of life.
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Affiliation(s)
- Nisi Jiang
- The Sam and Ann Barshop Institute for Longevity and Aging Studies, UT Health San Antonio; San Antonio, TX, U.S.A
- Department of Cellular and Integrative Physiology, UT Health San Antonio; San Antonio, TX, U.S.A
| | - Catherine J. Cheng
- The Sam and Ann Barshop Institute for Longevity and Aging Studies, UT Health San Antonio; San Antonio, TX, U.S.A
- Department of Cellular and Integrative Physiology, UT Health San Antonio; San Antonio, TX, U.S.A
| | - Qianqian Liu
- Department of Population Health Sciences, UT Health San Antonio; San Antonio, TX, U.S.A
| | - Randy Strong
- The Sam and Ann Barshop Institute for Longevity and Aging Studies, UT Health San Antonio; San Antonio, TX, U.S.A
- Department of Pharmacology, UT Health San Antonio; San Antonio, TX, U.S.A
- South Texas Veterans Health Care System, San Antonio, TX, U.S.A
| | - Jonathan Gelfond
- The Sam and Ann Barshop Institute for Longevity and Aging Studies, UT Health San Antonio; San Antonio, TX, U.S.A
- Department of Population Health Sciences, UT Health San Antonio; San Antonio, TX, U.S.A
| | - James F. Nelson
- The Sam and Ann Barshop Institute for Longevity and Aging Studies, UT Health San Antonio; San Antonio, TX, U.S.A
- Department of Cellular and Integrative Physiology, UT Health San Antonio; San Antonio, TX, U.S.A
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2
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Keshavarz M, Xie K, Bano D, Ehninger D. Aging - what it is and how to measure it. Mech Ageing Dev 2023:111837. [PMID: 37302556 DOI: 10.1016/j.mad.2023.111837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 05/27/2023] [Accepted: 06/08/2023] [Indexed: 06/13/2023]
Abstract
The current understanding of the biology of aging is largely based on research aimed at identifying factors that influence lifespan. However, lifespan as a sole proxy measure of aging has limitations because it can be influenced by specific pathologies (not generalized physiological deterioration in old age). Hence, there is a great need to discuss and design experimental approaches that are well-suited for studies targeting the biology of aging, rather than the biology of specific pathologies that restrict the lifespan of a given species. For this purpose, we here review various perspectives on aging, discuss agreement and disagreement among researchers on the definition of aging, and show that while slightly different aspects are emphasized, a widely accepted feature, shared across many definitions, is that aging is accompanied by phenotypic changes that occur in a population over the course of an average lifespan. We then discuss experimental approaches that are in line with these considerations, including multidimensional analytical frameworks as well as designs that facilitate the proper assessment of intervention effects on aging rate. The proposed framework can guide discovery approaches to aging mechanisms in all key model organisms (e.g., mouse, fish models, D. melanogaster, C. elegans) as well as in humans.
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Affiliation(s)
- Maryam Keshavarz
- Translational Biogerontology Lab, German Center for Neurodegenerative Diseases (DZNE), Venusberg-Campus 1, 53127 Bonn, Germany
| | - Kan Xie
- Translational Biogerontology Lab, German Center for Neurodegenerative Diseases (DZNE), Venusberg-Campus 1, 53127 Bonn, Germany
| | - Daniele Bano
- Aging and Neurodegeneration Lab, German Center for Neurodegenerative Diseases (DZNE), Venusberg-Campus 1, 53127 Bonn, Germany
| | - Dan Ehninger
- Translational Biogerontology Lab, German Center for Neurodegenerative Diseases (DZNE), Venusberg-Campus 1, 53127 Bonn, Germany.
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3
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Mulla S, Ludlam AR, Elragig A, Slack C, Balklava Z, Stich M, Cheong A. A biphasic model of lifespan in nematode Caenorhabditis elegans worm. ROYAL SOCIETY OPEN SCIENCE 2023; 10:220991. [PMID: 36756060 PMCID: PMC9890093 DOI: 10.1098/rsos.220991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 01/11/2023] [Indexed: 06/18/2023]
Abstract
Ageing research focuses on identifying lifespan modifiers and understanding and appropriately interpreting their effects. One of the most relevant quantities being studied is the shape of the survival curve that can reveal crucial information on the mechanism of action. Here, we introduce a bilogistic model to describe the shape of the lifespan curves of Caenorhabditis elegans populations. Using the corrected Akaike information criterion and the RMSE as goodness-of-fit tests, we show that the bilogistic model provides a better fit to the experimental data from nematode worms than other mathematical models and can identify and confirm biphasic lifespan data. Our parametric model offers a method to interpret replicate experiments data in terms of the shape parameters of the lifespan curve and enables robust statistical analysis of intra- and inter-group variance. We apply the model to novel lifespan data from C. elegans and Drosophila melanogaster and provide a rational statistical analysis of lifespan modifiers such as temperature and daf-16/FOXO mutation.
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Affiliation(s)
- Suhayl Mulla
- Life and Health Sciences, Aston University, Birmingham B4 7ET, UK
- Engineering and Applied Science, Aston University, Birmingham B4 7ET, UK
| | - Adele R. Ludlam
- Life and Health Sciences, Aston University, Birmingham B4 7ET, UK
| | - Aiman Elragig
- Engineering and Applied Science, Aston University, Birmingham B4 7ET, UK
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London W1S 4BS, UK
| | - Cathy Slack
- Life and Health Sciences, Aston University, Birmingham B4 7ET, UK
| | - Zita Balklava
- Life and Health Sciences, Aston University, Birmingham B4 7ET, UK
| | - Michael Stich
- Engineering and Applied Science, Aston University, Birmingham B4 7ET, UK
- Departmento de Matemática Aplicada, Ciencia e Ingeniería de los Materiales y Tecnología Electrónica, Universidad Rey Juan Carlos, 28933 Móstoles, Spain
| | - Alex Cheong
- Life and Health Sciences, Aston University, Birmingham B4 7ET, UK
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4
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Wang Q, Yang Z, Zhuang J, Zhang J, Shen F, Yu P, Zhong H, Feng F. Antiaging function of Chinese pond turtle (Chinemys reevesii) peptide through activation of the Nrf2/Keap1 signaling pathway and its structure-activity relationship. Front Nutr 2022; 9:961922. [PMID: 35938097 PMCID: PMC9355154 DOI: 10.3389/fnut.2022.961922] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Accepted: 06/24/2022] [Indexed: 11/16/2022] Open
Abstract
Chinese pond turtle is a traditional nourishing food with high nutritional value and bioactivity and has been considered a dietary remedy for prolonging the lifespan since ancient times. However, only limited information about their effects on longevity is available. This study was performed to assess the antioxidant activities and antiaging potential of Chinese pond turtle peptide (CPTP) using Drosophila melanogaster model and uncover the possible mechanisms underlying the beneficial effects. CPTP exhibited excellent antioxidant capability in vitro with IC50 values of 3.31, 1.93, and 9.52 mg/ml for 1,1-diphenyl-2-pycryl-hydrazyl (DPPH), 2,2-azinobis (3-ethylbenzothiazo-line-6-sulfonic acid) diammonium salt (ABTS), and hydroxyl radical scavenging, respectively. In vivo, 0.8% of CPTP significantly extended the mean and median lifespan of female flies by 7.66 and 7.85%, followed by enhanced resistance to oxidative and heat stress. Besides, CPTP remarkably increased the antioxidant enzyme activities and diminished the peroxide product accumulation. Furthermore, CPTP upregulated the relative mRNA expression of antioxidant-related genes, including nuclear factor-erythroid-2-like 2 (Nrf2) and its downstream target genes, while downregulated the expression of Kelch-like ECH-associated protein 1 (Keap1). Taken together, CPTP displayed promising potential in both antioxidant and antiaging effects on flies by targeting the Nrf2/Keap1 pathway. Further peptide sequence determination revealed that 89.23% of peptides from the identified sequences in CPTP could exert potential inhibitory effects on Keap1. Among these peptides, ten representative peptide sequences could actively interact with the binding sites of Keap1-Nrf2 interaction through hydrogen bonds, van der Walls, hydrophobic interactions, and electrostatic interactions. Conclusively, CPTP could be utilized as health-promoting bioactive peptide with antioxidant and antiaging capacities.
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Affiliation(s)
- Qianqian Wang
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
| | - Zherui Yang
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
| | - Jiachen Zhuang
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
| | - Junhui Zhang
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
| | - Fei Shen
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
| | - Peng Yu
- Yuyao Lengjiang Turtle Industry, Ningbo, China
| | - Hao Zhong
- College of Food Science and Technology, Zhejiang University of Technology, Hangzhou, China
- *Correspondence: Hao Zhong,
| | - Fengqin Feng
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
- Fengqin Feng,
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5
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Li GY, Zhang ZQ. Age-specific mortality and fecundity of a spider mite under diet restriction and delayed mating. INSECT SCIENCE 2022; 29:889-899. [PMID: 34264548 DOI: 10.1111/1744-7917.12948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 06/03/2021] [Accepted: 06/20/2021] [Indexed: 06/13/2023]
Abstract
Numerous experimental life-history studies on aging are mainly baised on two classical models-fruit fly Drosophila melanogaster (Meigen) and nematode Caenorhabditis elegans (Maupas)-with relatively little attention given to other organisms with different life-history characters. Two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) differs from many other arthropods in that the females continue their growth in the early adult stage and can reproduce sexually and asexually. In this study, the influences of dietary restriction and delayed mating on the aging patterns of the spider mite were examined with the prevailing survival and reproduction trade-off hypothesis of aging being tested. Significant sex-specific responses of the spider mites were found. The females showed longevity extension on diet restriction (fasting for 2 days in every 4 days) compared with their counterparts being fed ad libitum, and after delayed mating for 9 days, while the males displayed a decrease in lifespan when experiencing diet restriction but were not significantly influenced by delayed mating. Path analysis was used to investigate the relationship between mite survival and reproduction traits, including longevity, female lifetime reproduction, age at first reproduction, early reproductive efforts and late reproductive efforts, yielding no evidence for trade-offs between these life-history traits. The additive effects of dietary restriction and delayed mating in lifespan extension of female spider mites were confirmed, proving that diet restriction is a robust anti-aging intervention, and that later onset of reproduction can prolong adult lifespan in females.
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Affiliation(s)
- Guang-Yun Li
- Centre for Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland, Auckland, New Zealand
- Manaaki Whenua-Landcare Research, Auckland, New Zealand
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
| | - Zhi-Qiang Zhang
- Centre for Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland, Auckland, New Zealand
- Manaaki Whenua-Landcare Research, Auckland, New Zealand
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6
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Zhao X, Golic FT, Harrison BR, Manoj M, Hoffman EV, Simon N, Johnson R, MacCoss MJ, McIntyre LM, Promislow DEL. The metabolome as a biomarker of aging in Drosophila melanogaster. Aging Cell 2022; 21:e13548. [PMID: 35019203 PMCID: PMC8844127 DOI: 10.1111/acel.13548] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 11/12/2021] [Indexed: 12/15/2022] Open
Abstract
Many biomarkers have been shown to be associated not only with chronological age but also with functional measures of biological age. In human populations, it is difficult to show whether variation in biological age is truly predictive of life expectancy, as such research would require longitudinal studies over many years, or even decades. We followed adult cohorts of 20 Drosophila Genetic Reference Panel (DGRP) strains chosen to represent the breadth of lifespan variation, obtain estimates of lifespan, baseline mortality, and rate of aging, and associate these parameters with age‐specific functional traits including fecundity and climbing activity and with age‐specific targeted metabolomic profiles. We show that activity levels and metabolome‐wide profiles are strongly associated with age, that numerous individual metabolites show a strong association with lifespan, and that the metabolome provides a biological clock that predicts not only sample age but also future mortality rates and lifespan. This study with 20 genotypes and 87 metabolites, while relatively small in scope, establishes strong proof of principle for the fly as a powerful experimental model to test hypotheses about biomarkers and aging and provides further evidence for the potential value of metabolomic profiles as biomarkers of aging.
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Affiliation(s)
- Xiaqing Zhao
- Department of Lab Medicine and Pathology University of Washington School of Medicine Seattle US
| | - Forrest T. Golic
- Department of Lab Medicine and Pathology University of Washington School of Medicine Seattle US
| | - Benjamin R. Harrison
- Department of Lab Medicine and Pathology University of Washington School of Medicine Seattle US
| | - Meghna Manoj
- Department of Lab Medicine and Pathology University of Washington School of Medicine Seattle US
| | - Elise V. Hoffman
- Department of Lab Medicine and Pathology University of Washington School of Medicine Seattle US
| | - Neta Simon
- Department of Lab Medicine and Pathology University of Washington School of Medicine Seattle US
| | - Richard Johnson
- Department of Genome Sciences University of Washington School of Medicine Seattle US
| | - Michael J. MacCoss
- Department of Genome Sciences University of Washington School of Medicine Seattle US
| | - Lauren M. McIntyre
- Genetics Institute University of Florida Gainesville USA
- Department of Molecular Genetics and Microbiology University of Florida Gainesville USA
| | - Daniel E. L. Promislow
- Department of Lab Medicine and Pathology University of Washington School of Medicine Seattle US
- Department of Biology University of Washington Seattle US
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7
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Reichard M, Blažek R, Žák J, Cellerino A, Polačik M. The sources of sex differences in aging in annual fishes. J Anim Ecol 2021; 91:540-550. [PMID: 34954818 DOI: 10.1111/1365-2656.13656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 12/06/2021] [Indexed: 11/30/2022]
Abstract
Inter-sexual differences in lifespan (age at death) and aging (increase in mortality risk associated with functional deterioration) are widespread among animals, from nematodes to humans. Males often live shorter than females, but there is substantial unexplained variation among species and populations. Despite extensive research, it is poorly understood how lifespan differences between the sexes are modulated by an interplay among genetic, environmental and social factors. The goal of our study was to test how sex differences in lifespan and ageing are modulated by social and environmental factors, and by intrinsic differences between males and females. To disentangle the complex basis of sex differences in lifespan and aging, we combined comparative data from sex ratios in 367 natural populations of four species of African annual killifish with experimental results on sex differences in lifespan and aging from eight laboratory populations tested in treatments that varied social and environmental conditions. In the wild, females consistently outlived males. In captivity, sex-specific mortality depended on social conditions. In social-housed experimental groups, male-biased mortality persisted in two aggressive species, but ceased in two placid species. When social and physical contacts were prevented by housing all fish individually, male-biased mortality ceased in all four species. This outcome held across benign and challenging environmental conditions. Fitting demographic survival models revealed that increased baseline mortality was primarily responsible for a shorter male lifespan in social-housing conditions. The timing and rate of aging were not different between the sexes. No marker of functional aging we recorded in our study (lipofuscin accumulation, proliferative changes in kidney and liver) differed between males and females, despite their previously confirmed association with functional aging in Nothobranchius killifish. We show that sex differences in lifespan and aging in killifish are driven by a combination of social and environmental conditions, rather than differential functional aging. They are primarily linked to sexual selection but precipitated through multiple processes (predation, social interference). This demonstrates how sex-specific mortality varies among species even within an ecologically and evolutionary discrete lineage and explains how external factors mediate this difference.
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Affiliation(s)
- Martin Reichard
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic.,Department of Ecology and Vertebrate Zoology, Faculty of Biology and Environmental Protection, University of Łódź, Łódź, Poland.,Department of Botany and Zoology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Radim Blažek
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
| | - Jakub Žák
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic.,Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Alessandro Cellerino
- Bio@SNS, Scuola Normale Superiore, Department of Neurosciences, Pisa, Italy.,Fritz Lipmann Institute for Age Research, Leibniz Institute, Beutenbergstr. 11, Jena, Germany
| | - Matej Polačik
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
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8
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Common features of aging fail to occur in Drosophila raised without a bacterial microbiome. iScience 2021; 24:102703. [PMID: 34235409 PMCID: PMC8246586 DOI: 10.1016/j.isci.2021.102703] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 04/30/2021] [Accepted: 06/07/2021] [Indexed: 02/07/2023] Open
Abstract
Lifespan is limited both by intrinsic decline in vigor with age and by accumulation of external insults. There exists a general picture of the deficits of aging, one that is reflected in a pattern of age-correlated changes in gene expression conserved across species. Here, however, by comparing gene expression profiling of Drosophila raised either conventionally, or free of bacteria, we show that ∼70% of these conserved, age-associated changes in gene expression fail to occur in germ-free flies. Among the processes that fail to show time-dependent change under germ-free conditions are two aging features that are observed across phylogeny, declining expression of stress response genes and increasing expression of innate immune genes. These comprise adaptive strategies the organism uses to respond to bacteria, rather than being inevitable components of age-dependent decline. Changes in other processes are independent of the microbiome and can serve as autonomous markers of aging of the individual.
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9
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Nelson PG, Promislow DEL, Masel J. Biomarkers for Aging Identified in Cross-sectional Studies Tend to Be Non-causative. J Gerontol A Biol Sci Med Sci 2020; 75:466-472. [PMID: 31353411 DOI: 10.1093/gerona/glz174] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Indexed: 12/14/2022] Open
Abstract
Biomarkers are important tools for diagnosis, prognosis, and identification of the causal factors of physiological conditions. Biomarkers are typically identified by correlating biological measurements with the status of a condition in a sample of subjects. Cross-sectional studies sample subjects at a single timepoint, whereas longitudinal studies follow a cohort through time. Identifying biomarkers of aging is subject to unique challenges. Individuals who age faster have intrinsically higher mortality rates and so are preferentially lost over time, in a phenomenon known as cohort selection. In this article, we use simulations to show that cohort selection biases cross-sectional analysis away from identifying causal loci of aging, to the point where cross-sectional studies are less likely to identify loci that cause aging than if loci had been chosen at random. We go on to show this bias can be corrected by incorporating correlates of mortality identified from longitudinal studies, allowing cross-sectional studies to effectively identify the causal factors of aging.
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Affiliation(s)
- Paul G Nelson
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson
| | | | - Joanna Masel
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson
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10
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Kharat P, Sarkar P, Mouliganesh S, Tiwary V, Priya VBR, Sree NY, Annapoorna HV, Saikia DK, Mahanta K, Thirumurugan K. Ellagic acid prolongs the lifespan of Drosophila melanogaster. GeroScience 2019; 42:271-285. [PMID: 31786733 DOI: 10.1007/s11357-019-00135-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 11/06/2019] [Indexed: 12/11/2022] Open
Abstract
Wild-type Canton-S flies of Drosophila melanogaster were treated with ellagic acid at 100 μM and 200 μM concentrations. Longevity assay showed male flies fed with 200 μM ellagic acid displayed longer mean lifespan and maximum lifespan than control flies. Female flies fed with 200 μM ellagic acid laid less number of eggs than control. The eclosion time was less in female flies fed with 200 μM ellagic acid. Ellagic acid fed female flies performed better than male flies and control flies for heat shock tolerance and starvation stress. Male flies treated with 100 μM ellagic acid recovered faster from cold shock compared with control flies. Male and female flies treated with ellagic acid displayed increased survival following exposure to 5% hydrogen peroxide. Gene expression studies displayed upregulated expressions of CAT, dFOXO, ATG1, and SOD2 in ellagic acid-treated male flies, and upregulated expressions of dFOXO, CAT, and SOD2 in ellagic acid-treated female flies. Results from these studies show the pro-longevity effect of ellagic acid on Drosophila melanogaster.
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Affiliation(s)
- Priyanka Kharat
- 206, Structural Biology Laboratory, Centre for Biomedical Research, School of Biosciences & Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632 014, India
| | - Priyanka Sarkar
- 206, Structural Biology Laboratory, Centre for Biomedical Research, School of Biosciences & Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632 014, India
| | - S Mouliganesh
- 206, Structural Biology Laboratory, Centre for Biomedical Research, School of Biosciences & Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632 014, India
| | - Vaibhav Tiwary
- 206, Structural Biology Laboratory, Centre for Biomedical Research, School of Biosciences & Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632 014, India
| | - V B Ramya Priya
- 206, Structural Biology Laboratory, Centre for Biomedical Research, School of Biosciences & Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632 014, India
| | - N Yamini Sree
- 206, Structural Biology Laboratory, Centre for Biomedical Research, School of Biosciences & Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632 014, India
| | - H Vinu Annapoorna
- 206, Structural Biology Laboratory, Centre for Biomedical Research, School of Biosciences & Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632 014, India
| | - Diganta K Saikia
- 206, Structural Biology Laboratory, Centre for Biomedical Research, School of Biosciences & Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632 014, India
| | - Kaustav Mahanta
- 206, Structural Biology Laboratory, Centre for Biomedical Research, School of Biosciences & Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632 014, India
| | - Kavitha Thirumurugan
- 206, Structural Biology Laboratory, Centre for Biomedical Research, School of Biosciences & Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, 632 014, India.
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11
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Péron G, Lemaître JF, Ronget V, Tidière M, Gaillard JM. Variation in actuarial senescence does not reflect life span variation across mammals. PLoS Biol 2019; 17:e3000432. [PMID: 31518381 PMCID: PMC6760812 DOI: 10.1371/journal.pbio.3000432] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 09/25/2019] [Accepted: 08/29/2019] [Indexed: 12/22/2022] Open
Abstract
The concept of actuarial senescence (defined here as the increase in mortality hazards with age) is often confounded with life span duration, which obscures the relative role of age-dependent and age-independent processes in shaping the variation in life span. We use the opportunity afforded by the Species360 database, a collection of individual life span records in captivity, to analyze age-specific mortality patterns in relation to variation in life span. We report evidence of actuarial senescence across 96 mammal species. We identify the life stage (juvenile, prime-age, or senescent) that contributes the most to the observed variation in life span across species. Actuarial senescence only accounted for 35%-50% of the variance in life span across species, depending on the body mass category. We computed the sensitivity and elasticity of life span to five parameters that represent the three stages of the age-specific mortality curve-namely, the duration of the juvenile stage, the mean juvenile mortality, the prime-age (i.e., minimum) adult mortality, the age at the onset of actuarial senescence, and the rate of actuarial senescence. Next, we computed the between-species variance in these five parameters. Combining the two steps, we computed the relative contribution of each of the five parameters to the variance in life span across species. Variation in life span was increasingly driven by the intensity of actuarial senescence and decreasingly driven by prime-age adult mortality from small to large species because of changes in the elasticity of life span to these parameters, even if all the adult survival parameters consistently exhibited a canalization pattern of weaker variability among long-lived species than among short-lived ones. Our work unambiguously demonstrates that life span cannot be used to measure the strength of actuarial senescence, because a substantial and variable proportion of life span variation across mammals is not related to actuarial senescence metrics.
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Affiliation(s)
- Guillaume Péron
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Évolutive UMR5558, Villeurbanne, France
- * E-mail:
| | - Jean-François Lemaître
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Évolutive UMR5558, Villeurbanne, France
| | - Victor Ronget
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Évolutive UMR5558, Villeurbanne, France
| | - Morgane Tidière
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Évolutive UMR5558, Villeurbanne, France
| | - Jean-Michel Gaillard
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Évolutive UMR5558, Villeurbanne, France
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12
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A 2D analysis of correlations between the parameters of the Gompertz-Makeham model (or law?) of relationships between aging, mortality, and longevity. Biogerontology 2019; 20:799-821. [PMID: 31392450 DOI: 10.1007/s10522-019-09828-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 07/25/2019] [Indexed: 12/23/2022]
Abstract
When mortality (μ), aging rate (γ) and age (t) are treated according to the Gompertz model μ(t) = μ0eγt (GM), any mean age corresponds to a manifold of paired reciprocally changing μ0 and γ. Therefore, any noisiness of data used to derive GM parameters makes them negatively correlated. Besides this artifactual factor of the Strehler-Mildvan correlation (SMC), other factors emerge when the age-independent mortality C modifies survival according to the Gompertz-Makeham model μ(t) = C+μ0eγt (GMM), or body resources are partitioned between survival and protection from aging [the compensation effect of mortality (CEM)]. Theoretical curves in (γ, logμ0) coordinates show how μ0 decreases when γ increases upon a constant mean age. Within a species-specific range of γ, such "isoage" curves look as nearly parallel straight lines. The slopes of lines constructed by applying GM to survival curves modeled according to GMM upon changes in C are greater than the isoage slopes. When CEM is modeled, the slopes are still greater. Based on these observations, CEM is shown to contribute to SMC associated with sex differences in lifespan, with the effects of several life-extending drugs, and with recent trends in survival/mortality patterns in high-life-expectancy countries; whereas changes in C underlie differences between even high-life-expectancy countries, not only between high- and low-life-expectancy countries. Such interpretations make sense only if GM is not merely a statistical model, but rather reflects biological realities. Therefore, GM is discussed as derivable by applying certain constraints to a natural law termed the generalized Gompertz-Makeham law.
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Lenart P, Kuruczova D, Joshi PK, Bienertová-Vašků J. Male mortality rates mirror mortality rates of older females. Sci Rep 2019; 9:10589. [PMID: 31332232 PMCID: PMC6646351 DOI: 10.1038/s41598-019-47111-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 07/10/2019] [Indexed: 02/08/2023] Open
Abstract
Women on average live longer than men, which seems to suggest that women also age slower than men. However, the potential difference in the pace of aging between the sexes is a relatively controversial topic, and both positions, i.e. "men age faster" and "men and women age at the same pace", have found some support. We therefore employ parametric models previously established in model organisms as well as two nonparametric approaches to compare the pace of aging between the sexes using freely available mortality data from 13 high-income countries. Our results support the hypothesis that men age faster than women while also suggesting that the difference is small and that from a practical standpoint male mortality rates behave similarly to the mortality rates of women approximately eight years their senior.
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Affiliation(s)
- Peter Lenart
- Department of Pathological Physiology, Faculty of Medicine, Masaryk University, Kamenice 5, building A18, 625 00, Brno, Czech Republic.
- Research Centre for Toxic Compounds in the Environment, Faculty of Science, Masaryk University, Kamenice 5, building A29, 625 00, Brno, Czech Republic.
| | - Daniela Kuruczova
- Department of Pathological Physiology, Faculty of Medicine, Masaryk University, Kamenice 5, building A18, 625 00, Brno, Czech Republic
| | - Peter K Joshi
- Centre for Global Health Research, Usher Institute for Population Health Sciences and Informatics, University of Edinburgh, EH8 9AG, Edinburgh, UK
| | - Julie Bienertová-Vašků
- Department of Pathological Physiology, Faculty of Medicine, Masaryk University, Kamenice 5, building A18, 625 00, Brno, Czech Republic
- Research Centre for Toxic Compounds in the Environment, Faculty of Science, Masaryk University, Kamenice 5, building A29, 625 00, Brno, Czech Republic
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Cheng CJ, Gelfond JAL, Strong R, Nelson JF. Genetically heterogeneous mice exhibit a female survival advantage that is age- and site-specific: Results from a large multi-site study. Aging Cell 2019; 18:e12905. [PMID: 30801953 PMCID: PMC6516160 DOI: 10.1111/acel.12905] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 11/02/2018] [Accepted: 12/04/2018] [Indexed: 11/28/2022] Open
Abstract
The female survival advantage is a robust characteristic of human longevity. However, underlying mechanisms are not understood, and rodent models exhibiting a female advantage are lacking. Here, we report that the genetically heterogeneous (UM-HET3) mice used by the National Institute on Aging Interventions Testing Program (ITP) are such a model. Analysis of age-specific survival of 3,690 control ITP mice revealed a female survival advantage paralleling that of humans. As in humans, the female advantage in mice was greatest in early adulthood, peaking around 350 days of age and diminishing progressively thereafter. This persistent finding was observed at three geographically distinct sites and in six separate cohorts over a 10-year period. Because males weigh more than females and bodyweight is often inversely related to lifespan, we examined sex differences in the relationship between bodyweight and survival. Although present in both sexes, the inverse relationship between bodyweight and longevity was much stronger in males, indicating that male mortality is more influenced by bodyweight than is female mortality. In addition, male survival varied more across site and cohort than female survival, suggesting greater resistance of females to environmental modulators of survival. Notably, at 24 months the relationship between bodyweight and longevity shifted from negative to positive in both sexes, similar to the human condition in advanced age. These results indicate that the UM-HET3 mouse models the human female survival advantage and provide evidence for greater resilience of females to modulators of survival.
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Affiliation(s)
- Catherine J. Cheng
- Department of Cell Systems & AnatomyUT Health San AntonioSan AntonioTexas
- Barshop Institute for Longevity and Aging Studies, UT Health San AntonioSan AntonioTexas
| | - Jonathan A. L. Gelfond
- Barshop Institute for Longevity and Aging Studies, UT Health San AntonioSan AntonioTexas
- Department of Epidemiology and BiostatisticsUT Health San AntonioSan AntonioTexas
| | - Randy Strong
- Barshop Institute for Longevity and Aging Studies, UT Health San AntonioSan AntonioTexas
- South Texas Veterans Health Care SystemSan AntonioTexas
- Department of PharmacologyUT Health San AntonioSan AntonioTexas
| | - James F. Nelson
- Barshop Institute for Longevity and Aging Studies, UT Health San AntonioSan AntonioTexas
- Department of Cellular and Integrative PhysiologyUT Health San AntonioSan AntonioTexas
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Hoizumi M, Sato T, Shimizu T, Kato S, Tsukiyama K, Narita T, Fujita H, Morii T, Sassa MH, Seino Y, Yamada Y. Inhibition of GIP signaling extends lifespan without caloric restriction. Biochem Biophys Res Commun 2019; 513:974-982. [PMID: 31003779 DOI: 10.1016/j.bbrc.2019.04.036] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 04/04/2019] [Indexed: 01/02/2023]
Abstract
AIMS/INTRODUCTION Caloric restriction (CR) promotes longevity and exerts anti-aging effects by increasing Sirtuin production and activation. Gastric inhibitory polypeptide (GIP), a gastrointestinal peptide hormone, exerts various effects on pancreatic β-cells and extra-pancreatic tissues. GIP promotes glucose-dependent augmentation of insulin secretion and uptake of nutrients into the adipose tissue. MATERIALS AND METHODS Gipr-/- and Gipr+/+ mice were used for lifespan analysis, behavior experiments and gene expression of adipose tissue and muscles. 3T3-L1 differentiated adipocytes were used for Sirt1 and Nampt expression followed by treatment with GIP and α-lipoic acid. RESULTS We observed that GIP receptor-knockout (Gipr-/-) mice fed normal diet showed an extended lifespan, increased exploratory and decreased anxiety-based behaviors, which are characteristic behavioral changes under CR. Moreover, Gipr-/- mice showed increased Sirt1 and Nampt expression in the adipose tissue. GIP suppressed α-lipoic acid-induced Sirt1 expression and activity in differentiated adipocytes. CONCLUSIONS Although maintenance of CR is difficult, food intake and muscle endurance of Gipr-/- mice were similar to those of wild-type mice. Inhibition of GIP signaling may be a novel strategy to extend the lifespan of diabetic patients.
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Affiliation(s)
- Manabu Hoizumi
- Department of Endocrinology, Diabetes and Geriatric Medicine, Akita University Graduate School of Medicine, Japan
| | - Takehiro Sato
- Department of Endocrinology, Diabetes and Geriatric Medicine, Akita University Graduate School of Medicine, Japan
| | - Tatsunori Shimizu
- Department of Endocrinology, Diabetes and Geriatric Medicine, Akita University Graduate School of Medicine, Japan
| | - Shunsuke Kato
- Department of Endocrinology, Diabetes and Geriatric Medicine, Akita University Graduate School of Medicine, Japan
| | - Katsushi Tsukiyama
- Department of Endocrinology, Diabetes and Geriatric Medicine, Akita University Graduate School of Medicine, Japan
| | - Takuma Narita
- Department of Endocrinology, Diabetes and Geriatric Medicine, Akita University Graduate School of Medicine, Japan
| | - Hiroki Fujita
- Department of Endocrinology, Diabetes and Geriatric Medicine, Akita University Graduate School of Medicine, Japan
| | - Tsukasa Morii
- Department of Endocrinology, Diabetes and Geriatric Medicine, Akita University Graduate School of Medicine, Japan
| | - Mariko Harada Sassa
- Institute for Advancement of Clinical and Translational Science, Kyoto University Hospital, Japan
| | - Yutaka Seino
- Kansai Electric Power Medical Research Institute, Osaka, Japan
| | - Yuichiro Yamada
- Department of Endocrinology, Diabetes and Geriatric Medicine, Akita University Graduate School of Medicine, Japan.
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Anisimov VN, Labunets IF, Popovich IG, Tyndyk ML, Yurova MN, Golubev AG. In mice transgenic for IGF1 under keratin-14 promoter, lifespan is decreased and the rates of aging and thymus involution are accelerated. Aging (Albany NY) 2019; 11:2098-2110. [PMID: 30981207 PMCID: PMC6503882 DOI: 10.18632/aging.101903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 03/31/2019] [Indexed: 11/25/2022]
Abstract
IGF1 signaling is supposedly a key lifespan determinant in metazoans. However, controversial lifespan data were obtained with different means used to modify IGF1 or its receptor (IGF1R) expression in mice. The emerging puzzle lacks pieces of evidence needed to construct a coherent picture. We add to the available evidence by using the Gompertz model (GM), with account for the artifactual component of the Strehler-Mildvan correlation between its parameters, to compare the survival patterns of female FVB/N and FVB/N-derived K14/mIGF1 mice. In K14/mIGF1 vs. FVB/N mice, the rate of aging (γ) is markedly increased without concomitant changes in the initial mortality (μ0). In published cases where IGF1 signaling was altered by modifying liver or muscle IGF1 or whole body IGF1R expression, lifespan changes are attributable to μ0. The accelerated aging and associated tumor yield in K14/mIGF1 mice are consistent with the finding that the age-associated decreases in thymus weight and serum thymulin are accelerated in K14/mIGF1 mice. Our results underscore the importance of accounting for the mathematical artifacts of data fitting to GM in attempts to resolve discrepancies in survival data and to differentiate the contributions of the initial mortality and the rate of aging to changes in lifespan.
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Affiliation(s)
- Vladimir N Anisimov
- Department of Carcinogenesis and Oncogerontology, N.N. Petrov National Medical Research Center of Oncology, Saint Petersburg 197758, Russia
| | - Irina F Labunets
- Laboratory of Experimental Models, State Institute of Genetic and Regenerative Medicine, National Academy of Medical Sciences of Ukraine, Kiev 04114, Ukraine
| | - Irina G Popovich
- Department of Carcinogenesis and Oncogerontology, N.N. Petrov National Medical Research Center of Oncology, Saint Petersburg 197758, Russia
| | - Margarita L Tyndyk
- Department of Carcinogenesis and Oncogerontology, N.N. Petrov National Medical Research Center of Oncology, Saint Petersburg 197758, Russia
| | - Maria N Yurova
- Department of Carcinogenesis and Oncogerontology, N.N. Petrov National Medical Research Center of Oncology, Saint Petersburg 197758, Russia
| | - Alexey G Golubev
- Department of Carcinogenesis and Oncogerontology, N.N. Petrov National Medical Research Center of Oncology, Saint Petersburg 197758, Russia
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Golubev A, Panchenko A, Anisimov V. Applying parametric models to survival data: tradeoffs between statistical significance, biological plausibility, and common sense. Biogerontology 2018; 19:341-365. [PMID: 29869230 DOI: 10.1007/s10522-018-9759-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 05/30/2018] [Indexed: 12/18/2022]
Abstract
Parametric models for survival data help to differentiate aging from other lifespan determinants. However, such inferences suffer from small sizes of experimental animal samples and variable animals handling by different labs. We analyzed control data from a single laboratory where interventions in murine lifespan were studied over decades. The minimal Gompertz model (GM) was found to perform best with most murine strains. However, when several control datasets related to a particular strain are fitted to GM, strikingly rigid interdependencies between GM parameters emerge, consistent with the Strehler-Mildvan correlation (SMC). SMC emerges even when survival patterns do not conform to GM, as with cancer-prone HER2/neu mice, which die at a log-normally distributed age. Numerical experiments show that SMC includes an artifact whose magnitude depends on dataset deviation from conformance to GM irrespectively of the noisiness of small datasets, another contributor to SMC. Still another contributor to SMC is the compensation effect of mortality (CEM): a real tradeoff between the physiological factors responsible for initial vitality and the rate of its decline. To avoid misinterpretations, we advise checking experimental results against a SMC based on historical controls or on subgroups obtained by randomization of control animals. An apparent acceleration of aging associated with a decrease in the initial mortality is invalid if it is not greater than SMC suggests. This approach applied to published data suggests that the effects of calorie restriction and of drugs believed to mimic it are different. SMC and CEM relevance to human survival patterns is discussed.
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Affiliation(s)
- Alexey Golubev
- N.N. Petrov Research Institute of Oncology, Pesochny-2, Saint-Petersburg, 197758, Russia.
| | - Andrei Panchenko
- N.N. Petrov Research Institute of Oncology, Pesochny-2, Saint-Petersburg, 197758, Russia
| | - Vladimir Anisimov
- N.N. Petrov Research Institute of Oncology, Pesochny-2, Saint-Petersburg, 197758, Russia
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18
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Calorie restriction is the most reasonable anti-ageing intervention: a meta-analysis of survival curves. Sci Rep 2018; 8:5779. [PMID: 29636552 PMCID: PMC5893623 DOI: 10.1038/s41598-018-24146-z] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 03/22/2018] [Indexed: 01/08/2023] Open
Abstract
Despite technological advances, the survival records from longevity experiments remain the most indispensable tool in ageing-related research. A variety of interventions, including medications, genetic manipulations and calorie restriction (CR), have been demonstrated to extend the lifespan of several species. Surprisingly, few systematic studies have investigated the differences among these anti-ageing strategies using survival data. Here, we conduct a comprehensive and comparative meta-analysis of numerous published studies on Caenorhabditis elegans and Drosophila. We found that CR and genetic manipulations are generally more effective than medications at extending the total lifespan in both models, and CR can improve the ageing pattern of C. elegans. We further analysed the survival variation for different anti-ageing medications and determined that hypoglycaemic agents and antioxidants are advantageous despite only moderately increasing the overall lifespan; therefore, these two types of medications are promising CR mimetics. Analysis of genetic manipulations also indicated that the genes or pathways that extend lifespan in a healthier pattern are associated with CR. These results suggest that CR or CR mimetics may be the most reasonable and potentially beneficial anti-ageing strategy.
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19
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Tai TH, Noymer A. Models for estimating empirical Gompertz mortality: With an application to evolution of the Gompertzian slope. POPUL ECOL 2018. [DOI: 10.1007/s10144-018-0609-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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20
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A Reassessment of Genes Modulating Aging in Mice Using Demographic Measurements of the Rate of Aging. Genetics 2018; 208:1617-1630. [PMID: 29444805 PMCID: PMC5887152 DOI: 10.1534/genetics.118.300821] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 02/07/2018] [Indexed: 02/07/2023] Open
Abstract
Many studies have reported genetic interventions that have an effect on mouse life span; however, it is crucial to discriminate between manipulations of aging and aging-independent causes of life extension. Here, we used the Gompertz equation to determine whether previously reported aging-related mouse genes statistically affect the demographic rate of aging. Of 30 genetic manipulations previously reported to extend life span, for only two we found evidence of retarding demographic aging: Cisd2 and hMTH1. Of 24 genetic manipulations reported to shorten life span and induce premature aging features, we found evidence of five accelerating demographic aging: Casp2, Fn1, IKK-β, JunD, and Stub1. Overall, our reassessment found that only 15% of the genetic manipulations analyzed significantly affected the demographic rate of aging as predicted, suggesting that a relatively small proportion of interventions affecting longevity do so by regulating the rate of aging. By contrast, genetic manipulations affecting longevity tend to impact on aging-independent mortality. Our meta-analysis of multiple mouse longevity studies also reveals substantial variation in the controls used across experiments, suggesting that a short life span of controls is a potential source of bias. Overall, the present work leads to a reassessment of genes affecting the aging process in mice, with broad implications for our understanding of the genetics of mammalian aging and which genes may be more promising targets for drug discovery.
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21
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Briga M, Koetsier E, Boonekamp JJ, Jimeno B, Verhulst S. Food availability affects adult survival trajectories depending on early developmental conditions. Proc Biol Sci 2018; 284:rspb.2016.2287. [PMID: 28053061 DOI: 10.1098/rspb.2016.2287] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 12/01/2016] [Indexed: 12/18/2022] Open
Abstract
Food availability modulates survival in interaction with (for example) competition, disease and predators, but to what extent food availability in natural populations affects survival independent of these factors is not well known. We tested the effect of food availability on lifespan and actuarial senescence in a large population of captive zebra finches by increasing the effort required to obtain food, reflecting natural contrasts in food availability. Food availability may not affect all individuals equally and we therefore created heterogeneity in phenotypic quality by raising birds with different numbers of siblings. Low food availability had no effect on lifespan for individuals from benign developmental conditions (raised in small broods), but shortened lifespan for individuals from harsh developmental conditions. The lifespan difference arose through higher baseline mortality rate of individuals from harsh developmental conditions, despite a decrease in the rate of actuarial senescence. We found no evidence for sex-specific environmental sensitivity, but females lived shorter than males due to increased actuarial senescence. Thus, low food availability by itself shortens lifespan, but only in individuals from harsh developmental conditions. Our food availability manipulation resembles dietary restriction as applied to invertebrates, where it extends lifespan in model organisms and we discuss possible reasons for the contrasting results.
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Affiliation(s)
- Michael Briga
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Egbert Koetsier
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Jelle J Boonekamp
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Blanca Jimeno
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Simon Verhulst
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
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Nowak S, Neidhart J, Szendro IG, Rzezonka J, Marathe R, Krug J. Interaction Analysis of Longevity Interventions Using Survival Curves. BIOLOGY 2018; 7:biology7010006. [PMID: 29316622 PMCID: PMC5872032 DOI: 10.3390/biology7010006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 12/30/2017] [Accepted: 01/03/2018] [Indexed: 01/05/2023]
Abstract
A long-standing problem in ageing research is to understand how different factors contributing to longevity should be expected to act in combination under the assumption that they are independent. Standard interaction analysis compares the extension of mean lifespan achieved by a combination of interventions to the prediction under an additive or multiplicative null model, but neither model is fundamentally justified. Moreover, the target of longevity interventions is not mean life span but the entire survival curve. Here we formulate a mathematical approach for predicting the survival curve resulting from a combination of two independent interventions based on the survival curves of the individual treatments, and quantify interaction between interventions as the deviation from this prediction. We test the method on a published data set comprising survival curves for all combinations of four different longevity interventions in Caenorhabditis elegans. We find that interactions are generally weak even when the standard analysis indicates otherwise.
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Affiliation(s)
- Stefan Nowak
- Systems Biology of Ageing Cologne (Sybacol), University of Cologne, 50931 Cologne, Germany.
- Institut für Theoretische Physik, Universität zu Köln, 50937 Cologne, Germany.
| | - Johannes Neidhart
- Systems Biology of Ageing Cologne (Sybacol), University of Cologne, 50931 Cologne, Germany.
- Institut für Theoretische Physik, Universität zu Köln, 50937 Cologne, Germany.
- MBR Optical Systems, 42279 Wuppertal, Germany.
| | - Ivan G Szendro
- Systems Biology of Ageing Cologne (Sybacol), University of Cologne, 50931 Cologne, Germany.
- Institut für Theoretische Physik, Universität zu Köln, 50937 Cologne, Germany.
| | - Jonas Rzezonka
- Systems Biology of Ageing Cologne (Sybacol), University of Cologne, 50931 Cologne, Germany.
- Institut für Theoretische Physik, Universität zu Köln, 50937 Cologne, Germany.
| | - Rahul Marathe
- Systems Biology of Ageing Cologne (Sybacol), University of Cologne, 50931 Cologne, Germany.
- Institut für Theoretische Physik, Universität zu Köln, 50937 Cologne, Germany.
- Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, 110016 New Delhi, India.
| | - Joachim Krug
- Systems Biology of Ageing Cologne (Sybacol), University of Cologne, 50931 Cologne, Germany.
- Institut für Theoretische Physik, Universität zu Köln, 50937 Cologne, Germany.
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Latitudinal and age-specific patterns of larval mortality in the damselfly Lestes sponsa: Senescence before maturity? Exp Gerontol 2017; 95:107-115. [PMID: 28502774 DOI: 10.1016/j.exger.2017.05.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 04/27/2017] [Accepted: 05/09/2017] [Indexed: 11/21/2022]
Abstract
Latitudinal differences in life history traits driven by differences in seasonal time constraints have been widely documented. Yet, latitudinal patterns in (age-specific) mortality rates have been poorly studied. Here, we studied latitudinal differences in pre-adult age-specific mortality patterns in the strictly univoltine damselfly Lestes sponsa. We compared individuals from three latitudes reared from the egg stage in the laboratory at temperatures and photoperiods simulating those at the latitude of origin (main experiment) and under common-garden conditions at a fixed temperature and photoperiod (supplementary experiment). Results from the main experiment showed that the high-latitude population exhibited higher mortality rates than the central and southern populations, likely reflecting a cost of their faster development. Age-specific mortality patterns, also indicated higher ageing rates in the high-latitude compared to the low-latitude population, which likely had a genetic basis. The strong within-population variation in hatching dates in the low-latitude population caused variation in mortality rates; individuals that hatched later showed higher mortality rates presumably due to their shorter development times compared to larvae that hatched earlier. In both experiments, larvae from all three latitudes showed accelerated mortality rates with age, which is consistent with a pattern of senescence before adulthood.
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Harvanek ZM, Mourão MA, Schnell S, Pletcher SD. A computational approach to studying ageing at the individual level. Proc Biol Sci 2017; 283:rspb.2015.2346. [PMID: 26865300 DOI: 10.1098/rspb.2015.2346] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The ageing process is actively regulated throughout an organism's life, but studying the rate of ageing in individuals is difficult with conventional methods. Consequently, ageing studies typically make biological inference based on population mortality rates, which often do not accurately reflect the probabilities of death at the individual level. To study the relationship between individual and population mortality rates, we integrated in vivo switch experiments with in silico stochastic simulations to elucidate how carefully designed experiments allow key aspects of individual ageing to be deduced from group mortality measurements. As our case study, we used the recent report demonstrating that pheromones of the opposite sex decrease lifespan in Drosophila melanogaster by reversibly increasing population mortality rates. We showed that the population mortality reversal following pheromone removal was almost surely occurring in individuals, albeit more slowly than suggested by population measures. Furthermore, heterogeneity among individuals due to the inherent stochasticity of behavioural interactions skewed population mortality rates in middle-age away from the individual-level trajectories of which they are comprised. This article exemplifies how computational models function as important predictive tools for designing wet-laboratory experiments to use population mortality rates to understand how genetic and environmental manipulations affect ageing in the individual.
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Affiliation(s)
- Zachary M Harvanek
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA Medical Scientist Training Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Márcio A Mourão
- Mathematical Biosciences Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Santiago Schnell
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Scott D Pletcher
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA Geriatrics Center, University of Michigan, Ann Arbor, MI 48109, USA
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Shen J, Landis GN, Tower J. Multiple Metazoan Life-span Interventions Exhibit a Sex-specific Strehler-Mildvan Inverse Relationship Between Initial Mortality Rate and Age-dependent Mortality Rate Acceleration. J Gerontol A Biol Sci Med Sci 2017; 72:44-53. [PMID: 26893470 PMCID: PMC6292450 DOI: 10.1093/gerona/glw005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 01/07/2016] [Indexed: 11/14/2022] Open
Abstract
The Gompertz equation describes survival in terms of initial mortality rate (parameter a), indicative of health, and age-dependent acceleration in mortality rate (parameter b), indicative of aging. Gompertz parameters were analyzed for several published studies. In Drosophila females, mating increases egg production and decreases median life span, consistent with a trade-off between reproduction and longevity. Mating increased parameter a, causing decreased median life span, whereas time parameter b was decreased. The inverse correlation between parameters indicates the Strehler-Mildvan (S-M) relationship, where loss of low-vitality individuals yields a cohort with slower age-dependent mortality acceleration. The steroid hormone antagonist mifepristone/RU486 reversed these effects. Mating and mifepristone showed robust S-M relationships across genotypes, and dietary restriction showed robust S-M relationship across diets. Because nutrient optima differed between females and males, the same manipulation caused opposite effects on mortality rates in females versus males across a range of nutrient concentrations. Similarly, p53 mutation in Drosophila and mTOR mutation in mice caused increased median life span associated with opposite direction changes in mortality rate parameters in females versus males. The data demonstrate that dietary and genetic interventions have sex-specific and sometimes sexually opposite effects on mortality rates consistent with sexual antagonistic pleiotropy.
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Affiliation(s)
- Jie Shen
- College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Hangzhou, China
| | - Gary N Landis
- Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles
| | - John Tower
- Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles.
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26
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Blažek R, Polačik M, Kačer P, Cellerino A, Řežucha R, Methling C, Tomášek O, Syslová K, Terzibasi Tozzini E, Albrecht T, Vrtílek M, Reichard M. Repeated intraspecific divergence in life span and aging of African annual fishes along an aridity gradient. Evolution 2016; 71:386-402. [PMID: 27859247 DOI: 10.1111/evo.13127] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 11/07/2016] [Accepted: 11/09/2016] [Indexed: 01/22/2023]
Abstract
Life span and aging are substantially modified by natural selection. Across species, higher extrinsic (environmentally related) mortality (and hence shorter life expectancy) selects for the evolution of more rapid aging. However, among populations within species, high extrinsic mortality can lead to extended life span and slower aging as a consequence of condition-dependent survival. Using within-species contrasts of eight natural populations of Nothobranchius fishes in common garden experiments, we demonstrate that populations originating from dry regions (with short life expectancy) had shorter intrinsic life spans and a greater increase in mortality with age, more pronounced cellular and physiological deterioration (oxidative damage, tumor load), and a faster decline in fertility than populations from wetter regions. This parallel intraspecific divergence in life span and aging was not associated with divergence in early life history (rapid growth, maturation) or pace-of-life syndrome (high metabolic rates, active behavior). Variability across four study species suggests that a combination of different aging and life-history traits conformed with or contradicted the predictions for each species. These findings demonstrate that variation in life span and functional decline among natural populations are linked, genetically underpinned, and can evolve relatively rapidly.
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Affiliation(s)
- Radim Blažek
- Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Květná 8, 603 65, Brno, Czech Republic
| | - Matej Polačik
- Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Květná 8, 603 65, Brno, Czech Republic
| | - Petr Kačer
- Laboratory of Medicinal Diagnostics, Department of Organic Technology, University of Chemistry and Technology, Technická 5, 166 28, Prague, Czech Republic
| | - Alessandro Cellerino
- Bio@SNS, Scuola Normale Superiore, Department of Neurosciences, Piazza dei Cavalieri 7, 56126, Pisa, Italy.,Fritz Lipmann Institute for Age Research, Leibniz Institute, Beutenbergstr. 11, D-07745, Jena, Germany
| | - Radomil Řežucha
- Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Květná 8, 603 65, Brno, Czech Republic
| | - Caroline Methling
- Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Květná 8, 603 65, Brno, Czech Republic
| | - Oldřich Tomášek
- Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Květná 8, 603 65, Brno, Czech Republic.,Department of Zoology, Faculty of Sciences, Charles University in Prague, Viničná 7, 128 44, Praha, Czech Republic
| | - Kamila Syslová
- Laboratory of Medicinal Diagnostics, Department of Organic Technology, University of Chemistry and Technology, Technická 5, 166 28, Prague, Czech Republic
| | - Eva Terzibasi Tozzini
- Bio@SNS, Scuola Normale Superiore, Department of Neurosciences, Piazza dei Cavalieri 7, 56126, Pisa, Italy
| | - Tomáš Albrecht
- Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Květná 8, 603 65, Brno, Czech Republic.,Department of Zoology, Faculty of Sciences, Charles University in Prague, Viničná 7, 128 44, Praha, Czech Republic
| | - Milan Vrtílek
- Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Květná 8, 603 65, Brno, Czech Republic
| | - Martin Reichard
- Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Květná 8, 603 65, Brno, Czech Republic
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27
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Different Mechanisms of Longevity in Long-Lived Mouse and Caenorhabditis elegans Mutants Revealed by Statistical Analysis of Mortality Rates. Genetics 2016; 204:905-920. [PMID: 27638422 DOI: 10.1534/genetics.116.192369] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 08/28/2016] [Indexed: 12/23/2022] Open
Abstract
Mouse and Caenorhabditis elegans mutants with altered life spans are being used to investigate the aging process and how genes determine life span. The survival of a population can be modeled by the Gompertz function, which comprises two parameters. One of these parameters ("G") describes the rate at which mortality accelerates with age and is often described as the "rate of aging." The other parameter ("A") may correspond to the organism's baseline vulnerability to deleterious effects of disease and the environment. We show that, in mice, life-span-extending mutations systematically fail to affect the age-dependent acceleration of mortality (G), but instead affect only baseline vulnerability (A). This remains true even when comparing strains maintained under identical environmental conditions. In contrast, life-span-extending mutations in C. elegans were associated with decreases in G These observations on mortality rate kinetics suggest that the mechanisms of aging in mammals might fundamentally differ from those in nematodes.
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28
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Reichard M. Evolutionary ecology of aging: time to reconcile field and laboratory research. Ecol Evol 2016; 6:2988-3000. [PMID: 27069592 PMCID: PMC4809807 DOI: 10.1002/ece3.2093] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 02/25/2016] [Accepted: 03/03/2016] [Indexed: 12/19/2022] Open
Abstract
Aging is an increase in mortality risk with age due to a decline in vital functions. Research on aging has entered an exciting phase. Advances in biogerontology have demonstrated that proximate mechanisms of aging and interventions to modify lifespan are shared among species. In nature, aging patterns have proven more diverse than previously assumed. The paradigm that extrinsic mortality ultimately determines evolution of aging rates has been questioned and there appears to be a mismatch between intra‐ and inter‐specific patterns. The major challenges emerging in evolutionary ecology of aging are a lack of understanding of the complexity in functional senescence under natural conditions and unavailability of estimates of aging rates for matched populations exposed to natural and laboratory conditions. I argue that we need to reconcile laboratory and field‐based approaches to better understand (1) how aging rates (baseline mortality and the rate of increase in mortality with age) vary across populations within a species, (2) how genetic and environmental variation interact to modulate individual expression of aging rates, and (3) how much intraspecific variation in lifespan is attributable to an intrinsic (i.e., nonenvironmental) component. I suggest integration of laboratory and field assays using multiple matched populations of the same species, along with measures of functional declines.
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Affiliation(s)
- Martin Reichard
- Institute of Vertebrate Biology Academy of Sciences of the Czech Republic Brno Czech Republic
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29
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Shenoi VN, Ali SZ, Prasad NG. Evolution of increased adult longevity in Drosophila melanogaster populations selected for adaptation to larval crowding. J Evol Biol 2015; 29:407-17. [PMID: 26575793 DOI: 10.1111/jeb.12795] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 11/10/2015] [Indexed: 11/29/2022]
Abstract
In holometabolous animals such as Drosophila melanogaster, larval crowding can affect a wide range of larval and adult traits. Adults emerging from high larval density cultures have smaller body size and increased mean life span compared to flies emerging from low larval density cultures. Therefore, adaptation to larval crowding could potentially affect adult longevity as a correlated response. We addressed this issue by studying a set of large, outbred populations of D. melanogaster, experimentally evolved for adaptation to larval crowding for 83 generations. We assayed longevity of adult flies from both selected (MCUs) and control populations (MBs) after growing them at different larval densities. We found that MCUs have evolved increased mean longevity compared to MBs at all larval densities. The interaction between selection regime and larval density was not significant, indicating that the density dependence of mean longevity had not evolved in the MCU populations. The increase in longevity in MCUs can be partially attributed to their lower rates of ageing. It is also noteworthy that reaction norm of dry body weight, a trait probably under direct selection in our populations, has indeed evolved in MCU populations. To the best of our knowledge, this is the first report of the evolution of adult longevity as a correlated response of adaptation to larval crowding.
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Affiliation(s)
- V N Shenoi
- Indian Institute of Science Education and Research Mohali, Mohali, India
| | - S Z Ali
- Indian Institute of Science Education and Research Mohali, Mohali, India
| | - N G Prasad
- Indian Institute of Science Education and Research Mohali, Mohali, India
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30
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Boonekamp JJ, Briga M, Verhulst S. The heuristic value of redundancy models of aging. Exp Gerontol 2015; 71:95-102. [PMID: 26362219 DOI: 10.1016/j.exger.2015.09.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 09/03/2015] [Accepted: 09/04/2015] [Indexed: 11/18/2022]
Abstract
Molecular studies of aging aim to unravel the cause(s) of aging bottom-up, but linking these mechanisms to organismal level processes remains a challenge. We propose that complementary top-down data-directed modelling of organismal level empirical findings may contribute to developing these links. To this end, we explore the heuristic value of redundancy models of aging to develop a deeper insight into the mechanisms causing variation in senescence and lifespan. We start by showing (i) how different redundancy model parameters affect projected aging and mortality, and (ii) how variation in redundancy model parameters relates to variation in parameters of the Gompertz equation. Lifestyle changes or medical interventions during life can modify mortality rate, and we investigate (iii) how interventions that change specific redundancy parameters within the model affect subsequent mortality and actuarial senescence. Lastly, as an example of data-directed modelling and the insights that can be gained from this, (iv) we fit a redundancy model to mortality patterns observed by Mair et al. (2003; Science 301: 1731-1733) in Drosophila that were subjected to dietary restriction and temperature manipulations. Mair et al. found that dietary restriction instantaneously reduced mortality rate without affecting aging, while temperature manipulations had more transient effects on mortality rate and did affect aging. We show that after adjusting model parameters the redundancy model describes both effects well, and a comparison of the parameter values yields a deeper insight in the mechanisms causing these contrasting effects. We see replacement of the redundancy model parameters by more detailed sub-models of these parameters as a next step in linking demographic patterns to underlying molecular mechanisms.
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Affiliation(s)
- Jelle J Boonekamp
- Groningen Institute for Evolutionary Life Sciences University of Groningen P.O. Box 11103, 9700CC Groningen, The Netherlands.
| | - Michael Briga
- Groningen Institute for Evolutionary Life Sciences University of Groningen P.O. Box 11103, 9700CC Groningen, The Netherlands
| | - Simon Verhulst
- Groningen Institute for Evolutionary Life Sciences University of Groningen P.O. Box 11103, 9700CC Groningen, The Netherlands.
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31
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Gruber J, Chen CB, Fong S, Ng LF, Teo E, Halliwell B. Caenorhabditis elegans: What We Can and Cannot Learn from Aging Worms. Antioxid Redox Signal 2015; 23:256-79. [PMID: 25544992 DOI: 10.1089/ars.2014.6210] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
SIGNIFICANCE The nematode Caenorhabditis elegans is a widely used model organism for research into aging. However, nematodes diverged from other animals between 600 and 1300 million years ago. Beyond the intuitive impression that some aspects of aging appear to be universal, is there evidence that insights into the aging process of nematodes may be applicable to humans? RECENT ADVANCES There have been a number of results in nematodes that appear to contradict long-held beliefs about mechanisms and causes of aging. For example, ablation of several key antioxidant systems has often failed to result in lifespan shortening in C. elegans. CRITICAL ISSUES While it is clear that some central signaling pathways controlling lifespan are broadly conserved across large evolutionary distances, it is less clear to what extent downstream molecular mechanisms of aging are conserved. In this review we discuss the biology of C. elegans and mammals in the context of aging and age-dependent diseases. We consider evidence from studies that attempt to investigate basic, possibly conserved mechanisms of aging especially in the context of the free radical theory of aging. Practical points, such as the need for blinding of lifespan studies and for appropriate biomarkers, are also considered. FUTURE DIRECTIONS As data on the aging process(es) in different organisms increase, it is becoming increasingly clear that there are both conserved (public) and private aspects to aging. It is important to explore the dividing lines between these two aspects and to be aware of the large gray areas in-between.
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Affiliation(s)
- Jan Gruber
- 1 Department of Biochemistry, National University of Singapore , Singapore, Singapore .,2 Yale-NUS College , Singapore, Singapore
| | - Ce-Belle Chen
- 3 Department of Physics, National University of Singapore , Singapore, Singapore
| | - Sheng Fong
- 4 Duke-NUS Graduate Medical School , Singapore, Singapore
| | - Li Fang Ng
- 1 Department of Biochemistry, National University of Singapore , Singapore, Singapore
| | - Emelyne Teo
- 1 Department of Biochemistry, National University of Singapore , Singapore, Singapore
| | - Barry Halliwell
- 1 Department of Biochemistry, National University of Singapore , Singapore, Singapore
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32
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Lee KP. Dietary protein:carbohydrate balance is a critical modulator of lifespan and reproduction in Drosophila melanogaster: a test using a chemically defined diet. JOURNAL OF INSECT PHYSIOLOGY 2015; 75:12-19. [PMID: 25728576 DOI: 10.1016/j.jinsphys.2015.02.007] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 02/18/2015] [Accepted: 02/22/2015] [Indexed: 06/04/2023]
Abstract
Macronutrient balance is an important determinant of fitness in many animals, including insects. Previous studies have shown that altering the concentrations of yeast and sugar in the semi-synthetic media has a profound impact on lifespan in Drosophila melanogaster, suggesting that dietary protein:carbohydrate (P:C) balance is the main driver of lifespan and ageing processes. However, since yeast is rich in multiple nutrients other than proteins, this lifespan-determining role of dietary P:C balance needs to be further substantiated through trials using a chemically-defined, synthetic diet. In the present study, the effects of dietary P:C balance on lifespan and fecundity were investigated in female D. melanogaster flies fed on one of eight isocaloric synthetic diets differing in P:C ratio (0:1, 1:16, 1:8, 1:4, 1:2, 1:1, 2:1 or 4:1). Lifespan and dietary P:C ratio were related in a convex manner, with lifespan increasing to a peak at the two intermediate P:C ratios (1:2 and 1:4) and falling at the imbalanced ratios (0:1 and 4:1). Ingesting nutritionally imbalanced diets not only caused an earlier onset of senescence but also accelerated the age-dependent increase in mortality. Egg production was suppressed when flies were fed on a protein-deficient food (0:1), but increased with increasing dietary P:C ratio. Long-lived flies at the intermediate P:C ratios (1:2 and 1:4) stored a greater amount of lipids than those short-lived ones at the two imbalanced ratios (0:1 and 4:1). These findings provide a strong support to the notion that adequate dietary P:C balance is crucial for extending lifespan in D. melanogaster and offer new insights into how dietary P:C balance affects lifespan and ageing through its impacts on body composition.
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Affiliation(s)
- Kwang Pum Lee
- Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, Republic of Korea.
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33
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Weon BM. A solution to debates over the behavior of mortality at old ages. Biogerontology 2015; 16:375-81. [PMID: 25650286 DOI: 10.1007/s10522-015-9555-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 01/29/2015] [Indexed: 11/29/2022]
Abstract
As humans live longer, the precise modeling of mortality curves in very old age is becoming more important in aging research and public health. Here, we address a methodology that utilizes a modified stretched exponential survival function where a stretched exponent is relevant to heterogeneity in human populations. This function allows better estimation of the maximum human lifespan by providing a good description of the mortality curves in very old age. Demographic analysis of Swedish females over three recent decades revealed an important trend: the maximum human lifespan (existing around 125 years) gradually decreased at a constant rate of ~1.6 years per decade, while the characteristic life gradually increased at a constant rate of ~1.2 years per decade. This trend indicates that the number of aging people is increasingly concentrated at very old age, which is consistent with the definition of population aging. Importantly analyzing the stretched exponents would help in evaluating the heterogeneity trends in human populations.
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Affiliation(s)
- Byung Mook Weon
- School of Advanced Materials Science and Engineering, SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 440-746, Korea,
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34
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Gene pathways that delay Caenorhabditis elegans reproductive senescence. PLoS Genet 2014; 10:e1004752. [PMID: 25474471 PMCID: PMC4256158 DOI: 10.1371/journal.pgen.1004752] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 09/15/2014] [Indexed: 11/25/2022] Open
Abstract
Reproductive senescence is a hallmark of aging. The molecular mechanisms regulating reproductive senescence and its association with the aging of somatic cells remain poorly understood. From a full genome RNA interference (RNAi) screen, we identified 32 Caenorhabditis elegans gene inactivations that delay reproductive senescence and extend reproductive lifespan. We found that many of these gene inactivations interact with insulin/IGF-1 and/or TGF-β endocrine signaling pathways to regulate reproductive senescence, except nhx-2 and sgk-1 that modulate sodium reabsorption. Of these 32 gene inactivations, we also found that 19 increase reproductive lifespan through their effects on oocyte activities, 8 of them coordinate oocyte and sperm functions to extend reproductive lifespan, and 5 of them can induce sperm humoral response to promote reproductive longevity. Furthermore, we examined the effects of these reproductive aging regulators on somatic aging. We found that 5 of these gene inactivations prolong organismal lifespan, and 20 of them increase healthy life expectancy of an organism without altering total life span. These studies provide a systemic view on the genetic regulation of reproductive senescence and its intersection with organism longevity. The majority of these newly identified genes are conserved, and may provide new insights into age-associated reproductive senescence during human aging. Female reproductive senescence is one hallmark of human aging, and as the germline ages, there is increased incidence of chromosome non-dysjunction and DNA damage. Delayed childbearing is a general feature in modern society, resulting in high risk of infertility, miscarriage and birth defects. Thus, understanding the molecular mechanisms regulating reproductive senescence and its association with somatic senescence is increasingly relevant to human health, and will shed light on the prolongation of reproductive longevity and the improvement of post-reproductive health. Here we conducted a genomic screen in Caenorhabditis elegans, searching for genetic regulators of reproductive senescence. We identified 32 gene inactivations that extend reproductive lifespan. Functional characterization of these genes has revealed their interactions with insulin/IGF-1 and TGF-β signaling pathways, their effects in different genders on the regulation of reproductive longevity, and their implications in the control of healthy life expectancy. Many of these genes are conserved between worms and humans. Our studies thus provide new insights into the molecular control of reproductive aging and the mechanistic link between reproductive senescence and organism longevity.
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35
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Antosh M, Fox D, Hasselbacher T, Lanou R, Neretti N, Cooper LN. Drosophila melanogaster show a threshold effect in response to radiation. Dose Response 2014; 12:551-81. [PMID: 25552957 PMCID: PMC4267449 DOI: 10.2203/dose-response.13-047.antosh] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
We investigate the biological effects of radiation using adult Drosophila melanogaster as a model organism, focusing on gene expression and lifespan analysis to determine the effect of different radiation doses. Our results support a threshold effect in response to radiation: no effect on lifespan and no permanent effect on gene expression is seen at incident radiation levels below 100 J/kg. We also find that it is more appropriate to compare radiation effects in flies using the absorbed energy rather than incident radiation levels.
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Affiliation(s)
- Michael Antosh
- Institute for Brain and Neural Systems, Brown University
| | - David Fox
- Institute for Brain and Neural Systems, Brown University
| | | | | | - Nicola Neretti
- Institute for Brain and Neural Systems, Brown University
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University
| | - Leon N. Cooper
- Institute for Brain and Neural Systems, Brown University
- Department of Physics, Brown University
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36
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Archer CR, Duffy E, Hosken DJ, Mokkonen M, Okada K, Oku K, Sharma MD, Hunt J. Sex‐specific effects of natural and sexual selection on the evolution of life span and ageing in
Drosophila simulans. Funct Ecol 2014. [DOI: 10.1111/1365-2435.12369] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- C. Ruth Archer
- Centre for Ecology and Conservation College of Life and Environmental Sciences University of Exeter Penryn CampusTR10 9EZ UK
- Max Planck Research Group Modelling the Evolution of Ageing Max Planck Institute for Demographic Research Konrad‐Zuse‐Str. 1 18057 Rostock Germany
| | - Eoin Duffy
- Centre for Ecology and Conservation College of Life and Environmental Sciences University of Exeter Penryn CampusTR10 9EZ UK
- Institute of Environmental Science Jagiellonian University Gronostajowa 730‐387 Krakow Poland
| | - David J. Hosken
- Centre for Ecology and Conservation College of Life and Environmental Sciences University of Exeter Penryn CampusTR10 9EZ UK
| | - Mikael Mokkonen
- Centre for Ecology and Conservation College of Life and Environmental Sciences University of Exeter Penryn CampusTR10 9EZ UK
- Department of Biological and Environmental Science University of Jyväskylä P.O. Box 35 (YA)FI‐40014 Jyväskylä Finland
| | - Kensuke Okada
- Centre for Ecology and Conservation College of Life and Environmental Sciences University of Exeter Penryn CampusTR10 9EZ UK
- Laboratory of Evolutionary Ecology Graduate School of Environmental Sciences Okayama University Tsushima‐naka 1‐1‐1Okayama Japan
| | - Keiko Oku
- Centre for Ecology and Conservation College of Life and Environmental Sciences University of Exeter Penryn CampusTR10 9EZ UK
- Laboratory of Entomology Wageningen University P.O. Box 80316700 EH Wageningen The Netherlands
| | - Manmohan D. Sharma
- Centre for Ecology and Conservation College of Life and Environmental Sciences University of Exeter Penryn CampusTR10 9EZ UK
| | - John Hunt
- Centre for Ecology and Conservation College of Life and Environmental Sciences University of Exeter Penryn CampusTR10 9EZ UK
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37
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Barks PM, Laird RA. Senescence in duckweed: age‐related declines in survival, reproduction and offspring quality. Funct Ecol 2014. [DOI: 10.1111/1365-2435.12359] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Patrick M. Barks
- Department of Biological Sciences University of Lethbridge Lethbridge AlbertaT1K 3M4 Canada
| | - Robert A. Laird
- Department of Biological Sciences University of Lethbridge Lethbridge AlbertaT1K 3M4 Canada
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38
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Lohr JN, David P, Haag CR. Reduced lifespan and increased ageing driven by genetic drift in small populations. Evolution 2014; 68:2494-508. [PMID: 24897994 DOI: 10.1111/evo.12464] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 05/15/2014] [Indexed: 11/28/2022]
Abstract
Explaining the strong variation in lifespan among organisms remains a major challenge in evolutionary biology. Whereas previous work has concentrated mainly on differences in selection regimes and selection pressures, we hypothesize that differences in genetic drift may explain some of this variation. We develop a model to formalize this idea and show that the strong positive relationship between lifespan and genetic diversity predicted by this model indeed exists among populations of Daphnia magna, and that ageing is accelerated in small populations. Additional results suggest that this is due to increased drift in small populations rather than adaptation to environments favoring faster life histories. First, the correlation between genetic diversity and lifespan remains significant after statistical correction for potential environmental covariates. Second, no trade-offs are observed; rather, all investigated traits show clear signs of increased genetic load in the small populations. Third, hybrid vigor with respect to lifespan is observed in crosses between small but not between large populations. Together, these results suggest that the evolution of lifespan and ageing can be strongly affected by genetic drift, especially in small populations, and that variation in lifespan and ageing may often be nonadaptive, due to a strong contribution from mutation accumulation.
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Affiliation(s)
- Jennifer N Lohr
- Department of Biology, Ecology and Evolution, University of Fribourg, Chemin du Musée 10, 1700, Fribourg, Switzerland; Tvärminne Zoological Station, FIN-10900, Hanko, Finland.
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39
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Boonekamp JJ, Salomons M, Bouwhuis S, Dijkstra C, Verhulst S. Reproductive effort accelerates actuarial senescence in wild birds: an experimental study. Ecol Lett 2014; 17:599-605. [DOI: 10.1111/ele.12263] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Jelle J. Boonekamp
- Behavioural Biology; University of Groningen; P.O.Box 11103 9700CC Groningen The Netherlands
| | - Martijn Salomons
- Behavioural Biology; University of Groningen; P.O.Box 11103 9700CC Groningen The Netherlands
| | - Sandra Bouwhuis
- Behavioural Biology; University of Groningen; P.O.Box 11103 9700CC Groningen The Netherlands
- Institute of Avian Research; An der Vogelwarte 21 D-26386 Wilhelmshaven Germany
| | - Cor Dijkstra
- Behavioural Biology; University of Groningen; P.O.Box 11103 9700CC Groningen The Netherlands
| | - Simon Verhulst
- Behavioural Biology; University of Groningen; P.O.Box 11103 9700CC Groningen The Netherlands
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40
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Stone CM. Transient population dynamics of mosquitoes during sterile male releases: modelling mating behaviour and perturbations of life history parameters. PLoS One 2013; 8:e76228. [PMID: 24086715 PMCID: PMC3781073 DOI: 10.1371/journal.pone.0076228] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2012] [Accepted: 08/23/2013] [Indexed: 12/31/2022] Open
Abstract
The release of genetically-modified or sterile male mosquitoes offers a promising form of mosquito-transmitted pathogen control, but the insights derived from our understanding of male mosquito behaviour have not fully been incorporated into the design of such genetic control or sterile-male release methods. The importance of aspects of male life history and mating behaviour for sterile-male release programmes were investigated by projecting a stage-structured matrix model over time. An elasticity analysis of transient dynamics during sterile-male releases was performed to provide insight on which vector control methods are likely to be most synergistic. The results suggest that high mating competitiveness and mortality costs of released males are required before the sterile-release method becomes ineffective. Additionally, if released males suffer a mortality cost, older males should be released due to their increased mating capacity. If released males are of a homogenous size and size-assortative mating occurs in nature, this can lead to an increase in the abundance of large females and reduce the efficacy of the population-suppression effort. At a high level of size-assortative mating, the disease transmission potential of the vector population increases due to male releases, arguing for the release of a heterogeneously-sized male population. The female population was most sensitive to perturbations of density-dependent components of larval mortality and female survivorship and fecundity. These findings suggest source reduction might be a particularly effective complement to mosquito control based on the sterile insect technique (SIT). In order for SIT to realize its potential as a key component of an integrated vector-management strategy to control mosquito-transmitted pathogens, programme design of sterile-male release programmes must account for the ecology, behaviour and life history of mosquitoes. The model used here takes a step in this direction and can easily be modified to investigate additional aspects of mosquito behaviour or species-specific ecology.
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Affiliation(s)
- Christopher M. Stone
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- * E-mail:
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Simons MJP, Koch W, Verhulst S. Dietary restriction of rodents decreases aging rate without affecting initial mortality rate -- a meta-analysis. Aging Cell 2013; 12:410-4. [PMID: 23438200 DOI: 10.1111/acel.12061] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/12/2013] [Indexed: 12/22/2022] Open
Abstract
Dietary restriction (DR) extends lifespan in multiple species from various taxa. This effect can arise via two distinct but not mutually exclusive ways: a change in aging rate and/or vulnerability to the aging process (i.e. initial mortality rate). When DR affects vulnerability, this lowers mortality instantly, whereas a change in aging rate will gradually lower mortality risk over time. Unraveling how DR extends lifespan is of interest because it may guide toward understanding the mechanism(s) mediating lifespan extension and also has practical implications for the application of DR. We reanalyzed published survival data from 82 pairs of survival curves from DR experiments in rats and mice by fitting Gompertz and also Gompertz-Makeham models. The addition of the Makeham parameter has been reported to improve the estimation of Gompertz parameters. Both models separate initial mortality rate (vulnerability) from an age-dependent increase in mortality (aging rate). We subjected the obtained Gompertz parameters to a meta-analysis. We find that DR reduced aging rate without affecting vulnerability. The latter contrasts with the conclusion of a recent analysis of a largely overlapping data set, and we show how the earlier finding is due to a statistical artifact. Our analysis indicates that the biology underlying the life-extending effect of DR in rodents likely involves attenuated accumulation of damage, which contrasts with the acute effect of DR on mortality reported for Drosophila. Moreover, our findings show that the often-reported correlation between aging rate and vulnerability does not constrain changing aging rate without affecting vulnerability simultaneously.
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Affiliation(s)
- Mirre J. P. Simons
- Behavioural Biology Centre for Life Sciences University of Groningen PO Box 11103Groningen 9700CCThe Netherlands
| | - Wouter Koch
- Behavioural Biology Centre for Life Sciences University of Groningen PO Box 11103Groningen 9700CCThe Netherlands
| | - Simon Verhulst
- Behavioural Biology Centre for Life Sciences University of Groningen PO Box 11103Groningen 9700CCThe Netherlands
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Reciprocal cross differences in Drosophila melanogaster longevity: an evidence for non-genomic effects in heterosis phenomenon? Biogerontology 2013; 14:153-63. [PMID: 23529279 DOI: 10.1007/s10522-013-9419-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 03/21/2013] [Indexed: 12/20/2022]
Abstract
Reciprocal cross effects (i.e., differences between reciprocal hybrids that are developed by reversing the strains from which the dam and the sire are taken) are commonly used as a measure of sex-linkage or maternal effects. However, the papers reporting parental effects on life span of experimental animals are scarce. In order to investigate the potential of parent-of-origin effects for the longevity of hybrids, we determined the life spans of the inbred lines of Drosophila melanogaster [Oregon-R (OR), Canton-S (CS) and Uman (Um)] that differ significantly in longevity, as well as the life span of the progeny from the reciprocal crosses among them. The hybridization caused the increase in both flies' mean and maximum life span mainly shifting the survival curves upward proportionally at all ages. This resulted in the reduction in the Gompertz intercept (frailty) whereas the Gompertz slope (the rate of aging) was predominantly unchanged. Better-parent heterosis was observed in hybrids between OR and Um inbred lines and the extent of heterosis was more pronounced in hybrids between CS and Um inbred lines if long-lived parent was used as the female parent, and short-lived parent was used as the male parent in the crossing scheme. Such discrepancy in life span between reciprocal crosses may indicate that non-chromosomal factors are significantly contributing to a heterotic response. Our data are in line with the previous reports suggesting the involvement of non-genomic factors, particularly epigenetic events attributed to hybridization, in the manifestation of heterosis.
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SESN-1 is a positive regulator of lifespan in Caenorhabditis elegans. Exp Gerontol 2013; 48:371-9. [PMID: 23318476 DOI: 10.1016/j.exger.2012.12.011] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Revised: 11/20/2012] [Accepted: 12/22/2012] [Indexed: 01/20/2023]
Abstract
Aging is a process of gradual functional decline leading to death. Reactive oxygen species (ROS) not only contribute to oxidative stress and cell damage that lead to aging but also serve as signaling molecules. Sestrins are evolutionarily conserved in all multicellular organisms and are required for regenerating hyperoxidized forms of peroxiredoxins and ROS clearance. However, whether sestrins regulate longevity in metazoans is still unclear. Here, we demonstrated that SESN-1, the only sestrin ortholog in Caenorhabditis elegans, is a positive regulator of lifespan. sesn-1 gene mutant worms had significantly shorter lifespans compared to wild-type animals, and overexpression of sesn-1 prolonged lifespan. Moreover, sesn-1 was found to play a key role in defense against several life stressors, including heat, hydrogen peroxide and the heavy metal copper; and sesn-1 mutants expressed higher levels of ROS and showed a decline in body muscle function. Surprisingly, loss of sesn-1 did not weaken the innate immune function of the worms. Together, these results suggest that SESN-1 is required for normal lifespan and its function in muscle cells prevents muscle degeneration over a lifetime.
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Linford NJ, Bilgir C, Ro J, Pletcher SD. Measurement of lifespan in Drosophila melanogaster. J Vis Exp 2013:50068. [PMID: 23328955 DOI: 10.3791/50068] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Aging is a phenomenon that results in steady physiological deterioration in nearly all organisms in which it has been examined, leading to reduced physical performance and increased risk of disease. Individual aging is manifest at the population level as an increase in age-dependent mortality, which is often measured in the laboratory by observing lifespan in large cohorts of age-matched individuals. Experiments that seek to quantify the extent to which genetic or environmental manipulations impact lifespan in simple model organisms have been remarkably successful for understanding the aspects of aging that are conserved across taxa and for inspiring new strategies for extending lifespan and preventing age-associated disease in mammals. The vinegar fly, Drosophila melanogaster, is an attractive model organism for studying the mechanisms of aging due to its relatively short lifespan, convenient husbandry, and facile genetics. However, demographic measures of aging, including age-specific survival and mortality, are extraordinarily susceptible to even minor variations in experimental design and environment, and the maintenance of strict laboratory practices for the duration of aging experiments is required. These considerations, together with the need to practice careful control of genetic background, are essential for generating robust measurements. Indeed, there are many notable controversies surrounding inference from longevity experiments in yeast, worms, flies and mice that have been traced to environmental or genetic artifacts(1-4). In this protocol, we describe a set of procedures that have been optimized over many years of measuring longevity in Drosophila using laboratory vials. We also describe the use of the dLife software, which was developed by our laboratory and is available for download (http://sitemaker.umich.edu/pletcherlab/software). dLife accelerates throughput and promotes good practices by incorporating optimal experimental design, simplifying fly handling and data collection, and standardizing data analysis. We will also discuss the many potential pitfalls in the design, collection, and interpretation of lifespan data, and we provide steps to avoid these dangers.
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Affiliation(s)
- Nancy J Linford
- Department of Molecular and Integrative Physiology, University of Michigan, Michigan, USA.
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45
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Sun Y, Yolitz J, Wang C, Spangler E, Zhan M, Zou S. Aging studies in Drosophila melanogaster. Methods Mol Biol 2013; 1048:77-93. [PMID: 23929099 DOI: 10.1007/978-1-62703-556-9_7] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Drosophila is a genetically tractable system ideal for investigating the mechanisms of aging and developing interventions for promoting healthy aging. Here we describe methods commonly used in Drosophila aging research. These include basic approaches for preparation of diets and measurements of lifespan, food intake, and reproductive output. We also describe some commonly used assays to measure changes in physiological and behavioral functions of Drosophila in aging, such as stress resistance and locomotor activity.
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Affiliation(s)
- Yaning Sun
- Translational Gerontology Branch, National Institute on Aging, Baltimore, MD, USA
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46
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Moorad JA, Promislow DEL, Flesness N, Miller RA. A comparative assessment of univariate longevity measures using zoological animal records. Aging Cell 2012; 11:940-8. [PMID: 22805302 DOI: 10.1111/j.1474-9726.2012.00861.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Comparative biogerontology evaluates cellular, molecular, physiological, and genomic properties that distinguish short-lived from long-lived species. These studies typically use maximum reported lifespan (MRLS) as the index with which to compare traits, but there is a general awareness that MRLS is not ideal owing to statistical shortcomings that include bias resulting from small sample sizes. Nevertheless, MRLS has enough species-specific information to show strong associations with many other species-specific traits, such as body mass, stress resistance, and codon usage. The major goal of this study was to see if we could identify surrogate measures with better statistical properties than MRLS but that still capture inter-species differences in extreme lifespan. Using zoological records of 181 bird and mammal species, we evaluated 16 univariate metrics of aging and longevity, including nonparametric quantile-based measures and parameters derived from demographic models of aging, for three desirable statistical properties. We wished to identify those measures that: (i) correlated well with MRLS when the biasing effects of sample size were removed; (ii) correlated weakly with population size; and (iii) were highly robust to the effects of sampling error. Nonparametric univariate descriptors of the distribution of lifespans clearly outperformed the measures derived from demographic analyses. Mean adult lifespan and quantile-based measures, and in particular the 90th quantile of longevity, performed particularly well, demonstrating far less sensitivity to small sample size effects than MRLS while preserving much of the information contained in the maximum lifespan measure. These measures should take the place of MRLS in comparative studies of lifespan.
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Archer CR, Sakaluk SK, Selman C, Royle NJ, Hunt J. Oxidative stress and the evolution of sex differences in life span and ageing in the decorated cricket, Gryllodes sigillatus. Evolution 2012; 67:620-34. [PMID: 23461314 DOI: 10.1111/j.1558-5646.2012.01805.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The Free Radical Theory of Ageing (FRTA) predicts that oxidative stress, induced when levels of reactive oxygen species exceed the capacity of antioxidant defenses, causes ageing. Recently, it has also been argued that oxidative damage may mediate important life-history trade-offs. Here, we use inbred lines of the decorated cricket, Gryllodes sigillatus, to estimate the genetic (co)variance between age-dependent reproductive effort, life span, ageing, oxidative damage, and total antioxidant capacity within and between the sexes. The FRTA predicts that oxidative damage should accumulate with age and negatively correlate with life span. We find that protein oxidation is greater in the shorter lived sex (females) and negatively genetically correlated with life span in both sexes. However, oxidative damage did not accumulate with age in either sex. Previously we have shown antagonistic pleiotropy between the genes for early-life reproductive effort and ageing rate in both sexes, although this was stronger in females. In females, we find that elevated fecundity early in life is associated with greater protein oxidation later in life, which is in turn positively correlated with the rate of ageing. Our results provide mixed support for the FRTA but suggest that oxidative stress may mediate sex-specific life-history strategies in G. sigillatus.
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Affiliation(s)
- Catharine R Archer
- Centre for Ecology and Conservation, The University of Exeter, Cornwall Campus, Penryn, Cornwall, TR10 9EZ, United Kingdom
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48
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Soh JW, Marowsky N, Nichols TJ, Rahman AM, Miah T, Sarao P, Khasawneh R, Unnikrishnan A, Heydari AR, Silver RB, Arking R. Curcumin is an early-acting stage-specific inducer of extended functional longevity in Drosophila. Exp Gerontol 2012; 48:229-39. [PMID: 23063786 DOI: 10.1016/j.exger.2012.09.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 07/27/2012] [Accepted: 09/27/2012] [Indexed: 01/07/2023]
Abstract
Larval feeding with curcumin induces an extended health span with significantly increased median and maximum longevities in the adult fly. This phenotype is diet insensitive and shows no additive effect on longevity when combined with an adult dietary restriction (DR) diet, suggesting that curcumin and DR operate via the same or overlapping pathways for this trait. This treatment significantly slows the aging rate so that it is comparable with that of genetically selected long lived animals. The larval treatment also enhances the adult animal's geotactic activity in an additive manner with DR, suggesting that curcumin and DR may use different pathways for different traits. Feeding the drug to adults during only the health span also results in a significantly extended health span with increased median and maximum life span. This extended longevity phenotype is induced only during these stage-specific periods. Feeding adults with the drug over their whole life results in a weakly negative effect on median longevity with no increase in maximum life span. There are no negative effects on reproduction, although larval curcumin feeding increases development time, and also apparently accelerates the normal late-life neuromuscular degeneration seen in the legs. Gene expression data from curcumin-fed larvae shows that the TOR pathway is inhibited in the larvae and the young to midlife adults, although several other genes involved in longevity extension are also affected. These data support the hypothesis that curcumin acts as if it is a DR mimetic nutraceutical. These data also suggest that the search for DR mimetics may be enhanced by the use of stage-specific screening of candidate molecules.
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Affiliation(s)
- Jung-Won Soh
- Department of Biological Sciences, Wayne State University, Detroit, 48202, USA.
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49
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McDonald P, Maizi BM, Arking R. Chemical regulation of mid- and late-life longevities in Drosophila. Exp Gerontol 2012; 48:240-9. [PMID: 23044027 DOI: 10.1016/j.exger.2012.09.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 09/26/2012] [Accepted: 09/27/2012] [Indexed: 01/16/2023]
Abstract
We tested the effects of a Class I histone deacetylase inhibitor (HDAcI), sodium butyrate (NaBu), on the longevity of normal- and long-lived strains of Drosophila melanogaster. This HDAcI has mixed effects in the normal-lived Ra strain as it decreases mortality rates and increases longevity when administered in the transition or senescent spans, but decreases longevity when administered over the health span only or over the entire adult lifespan. Mostly deleterious effects are noted when administered by either method to the long-lived La strain. Thus "mid- to late-life" drugs may have different stage-specific effects on different genomes of a model organism. A different HDAcI (suberoylanilide hydroxamic acid, SAHA) administered to the normal-lived strain showed similar late-life extending effects, suggesting that this is not an isolated effect of one drug. These data also show that the use of an HDAcI can significantly alter the mortality rate of the senescent span by decreasing its vulnerability, or short-term risk of death, in a manner similar to that of dietary restriction. These studies may help to shed light on the frailty syndrome affecting some aging organisms.
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Affiliation(s)
- Philip McDonald
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, United States.
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50
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Stone CM, Jackson BT, Foster WA. Effects of plant-community composition on the vectorial capacity and fitness of the malaria mosquito Anopheles gambiae. Am J Trop Med Hyg 2012; 87:727-36. [PMID: 22927493 DOI: 10.4269/ajtmh.2012.12-0123] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Dynamics of Anopheles gambiae abundance and malaria transmission potential rely strongly on environmental conditions. Female and male An. gambiae use sugar and are affected by its absence, but how the presence or absence of nectariferous plants affects An. gambiae abundance and vectorial capacity has not been studied. We report on four replicates of a cohort study performed in mesocosms with sugar-poor and sugar-rich plants, in which we measured mosquito survival, biting rates, and fecundity. Survivorship was greater with access to sugar-rich plant species, and mortality patterns were age-dependent. Sugar-poor populations experienced Weibull mortality patterns, and of four populations in the sugar-rich environment, two female and three male subpopulations were better fitted by Gompertz functions. A tendency toward higher biting rates in sugar-poor mesocosms, particularly for young females, was found. Therefore, vectorial capacity was pulled in opposing directions by nectar availability, resulting in highly variable vectorial capacity values.
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Affiliation(s)
- Christopher M Stone
- Department of Entomology, University of Kentucky, Lexington, KY 40546-0091, USA.
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