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Lidsky PV, Yuan J, Rulison JM, Andino-Pavlovsky R. Is Aging an Inevitable Characteristic of Organic Life or an Evolutionary Adaptation? BIOCHEMISTRY. BIOKHIMIIA 2022; 87:1413-1445. [PMID: 36717438 PMCID: PMC9839256 DOI: 10.1134/s0006297922120021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 09/27/2022] [Accepted: 11/04/2022] [Indexed: 01/15/2023]
Abstract
Aging is an evolutionary paradox. Several hypotheses have been proposed to explain it, but none fully explains all the biochemical and ecologic data accumulated over decades of research. We suggest that senescence is a primitive immune strategy which acts to protect an individual's kin from chronic infections. Older organisms are exposed to pathogens for a longer period of time and have a higher likelihood of acquiring infectious diseases. Accordingly, the parasitic load in aged individuals is higher than in younger ones. Given that the probability of pathogen transmission is higher within the kin, the inclusive fitness cost of infection might exceed the benefit of living longer. In this case, programmed lifespan termination might be an evolutionarily stable strategy. Here, we discuss the classical evolutionary hypotheses of aging and compare them with the pathogen control hypothesis, discuss the consistency of these hypotheses with existing empirical data, and present a revised conceptual framework to understand the evolution of aging.
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Affiliation(s)
- Peter V Lidsky
- Department of Microbiology and Immunology, University of California San Francisco, CA, USA.
| | - Jing Yuan
- Department of Microbiology and Immunology, University of California San Francisco, CA, USA
| | - Jacob M Rulison
- Department of Microbiology and Immunology, University of California San Francisco, CA, USA
- University of California Berkeley, CA, USA
| | - Raul Andino-Pavlovsky
- Department of Microbiology and Immunology, University of California San Francisco, CA, USA.
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2
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Winterhalter PR, Simm A. How Justified is the Assumption of Programmed Aging in Reminiscence of Weismann's Theories? BIOCHEMISTRY. BIOKHIMIIA 2022; 87:35-53. [PMID: 35491022 DOI: 10.1134/s0006297922010047] [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: 10/02/2021] [Revised: 11/30/2021] [Accepted: 12/15/2021] [Indexed: 06/14/2023]
Abstract
Theories about the benefits of death and the resulting increased likelihood of programmed aging are controversial, advocated only by a minority. The extent to which their assumptions might be justified should be investigated. To this end, various approaches to the possible utility or origin were considered, particularly potential benefits of the faster generational change caused by possible evolutionary compound interest. Reference was made to the thinking of Weismann, the father of regulated aging theories, who advocated non-adaptive concepts at the end of his career. In a thought experiment, circadian rhythms are discussed as a possible molecular source of aging regulation.
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Affiliation(s)
| | - Andreas Simm
- Martin-Luther-University of Halle-Wittenberg, Halle (Saale), 06120, Germany
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3
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Khalsa DS, Newberg AB. Spiritual Fitness: A New Dimension in Alzheimer's Disease Prevention. J Alzheimers Dis 2021; 80:505-519. [PMID: 33554917 PMCID: PMC8075383 DOI: 10.3233/jad-201433] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/08/2021] [Indexed: 01/17/2023]
Abstract
BACKGROUND Religious and spiritual interventions may have an effect on Alzheimer's disease prevention. Kirtan Kriya meditation has been shown to mitigate the deleterious effects of chronic stress on cognition, reverse memory loss, and create psychological and spiritual wellbeing, which may reduce multiple drivers of Alzheimer's disease risk. OBJECTIVE To detail a new concept in medicine called Spiritual Fitness, a merging of stress reduction, basic wellbeing, and psycho/spiritual wellbeing to prevent Alzheimer's disease. METHODS The literature on the topics mentioned above is described, including an in-depth discussion on why and how each are critical to advancing the future of Alzheimer's disease prevention. The many negative effects of chronic stress, and the benefits of Kirtan Kriya, are reviewed. The four pillars of basic wellbeing, six practical aspects of psychological wellbeing, and the four new non-sectarian features of spiritual fitness are then disclosed. Moreover, instructions on practicing Kirtan Kriya are offered in the Supplementary Material. CONCLUSION Religious and spiritual practices, including Kirtan Kriya, are crucial components in the development of enhanced cognition and well-being, which may help prevent and, in some cases, reverse cognitive decline. The key point of this review is that making a commitment to live a brain longevity lifestyle including spiritual fitness is a critically important way for aging Alzheimer's disease free. We hope that this article will inspire scientists, clinicians, and patients to embrace this new concept of spiritual fitness and make it a part of every multidomain program for the prevention of cognitive disability.
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Affiliation(s)
| | - Andrew B. Newberg
- Department of Integrative Medicine and Nutritional Sciences, Department of Radiology, Marcus Institute of Integrative Health, Thomas Jefferson University, Philadelphia, PA, USA
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4
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Vitousek MN, Taff CC, Ryan TA, Zimmer C. Stress Resilience and the Dynamic Regulation of Glucocorticoids. Integr Comp Biol 2019; 59:251-263. [PMID: 31168615 DOI: 10.1093/icb/icz087] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Vertebrates respond to a diversity of stressors by rapidly elevating glucocorticoid (GC) levels. The changes in physiology and behavior triggered by this response can be crucial for surviving a variety of challenges. Yet the same process that is invaluable in coping with immediate threats can also impose substantial damage over time. In addition to the pathological effects of long-term exposure to stress hormones, even relatively brief elevations can impair the expression of a variety of behaviors and physiological processes central to fitness, including sexual behavior, parental behavior, and immune function. Therefore, the ability to rapidly and effectively terminate the short-term response to stress may be fundamental to surviving and reproducing in dynamic environments. Here we review the evidence that variation in the ability to terminate the stress response through negative feedback is an important component of stress coping capacity. We suggest that coping capacity may also be influenced by variation in the dynamic regulation of GCs-specifically, the ability to rapidly turn on and off the stress response. Most tests of the fitness effects of these traits to date have focused on organisms experiencing severe or prolonged stressors. Here we use data collected from a long-term study of tree swallows (Tachycineta bicolor) to test whether variation in negative feedback, or other measures of GC regulation, predict components of fitness in non-chronically stressed populations. We find relatively consistent, but generally weak relationships between different fitness components and the strength of negative feedback. Reproductive success was highest in individuals that both mounted a robust stress response and had strong negative feedback. We did not see consistent evidence of a relationship between negative feedback and adult or nestling survival: negative feedback was retained in the best supported models of nestling and adult survival, but in two of three survival-related analyses the intercept-only model received only slightly less support. Both negative feedback and stress-induced GC levels-but not baseline GCs-were individually repeatable. These measures of GC activity did not consistently covary across ages and life history stages, indicating that they are independently regulated. Overall, the patterns seen here are consistent with the predictions that negative feedback-and the dynamic regulation of GCs-are important components of stress coping capacity, but that the fitness benefits of having strong negative feedback during the reproductive period are likely to manifest primarily in individuals exposed to chronic or repeated stressors.
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Affiliation(s)
- Maren N Vitousek
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA.,Cornell Lab of Ornithology, Ithaca, NY 14850, USA
| | - Conor C Taff
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA.,Cornell Lab of Ornithology, Ithaca, NY 14850, USA
| | - Thomas A Ryan
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
| | - Cedric Zimmer
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
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5
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Hargis K, Buechel HM, Popovic J, Blalock EM. Acute psychosocial stress in mid-aged male rats causes hyperthermia, cognitive decline, and increased deep sleep power, but does not alter deep sleep duration. Neurobiol Aging 2018; 70:78-85. [PMID: 30007167 PMCID: PMC6119089 DOI: 10.1016/j.neurobiolaging.2018.06.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 05/08/2018] [Accepted: 06/05/2018] [Indexed: 10/14/2022]
Abstract
Aging is associated with altered sleep architecture and worsened hippocampus-dependent cognition, highly prevalent clinical conditions that detract from quality of life for the elderly. Interestingly, exposure to psychosocial stress causes similar responses in young subjects, suggesting that age itself may act as a stressor. In prior work, we demonstrated that young animals show loss of deep sleep, deficits in cognition, and elevated body temperature after acute stress exposure, whereas aged animals are hyporesponsive on these measures. However, it is unclear if these age-altered stress responses occur in parallel over the course of aging. To address this, here we repeated the experiment in mid-aged animals. We hypothesized that mid-aged stress responses would be intermediate between those of young and aged subjects. Sixteen mid-aged (12 months) male F344 rats were implanted with EEG/EMG emitters to monitor sleep architecture and body temperature, and were trained on the Morris water maze for 3 days. On the fourth day, half of the subjects were restrained for 3 hours immediately before the water maze probe trial. Sleep architecture and body temperature were measured during the ensuing inactive period, and on the following day, endpoint measures were taken. Restrained mid-aged animals showed resistance to deep sleep loss, but demonstrated stress-induced water maze probe trial performance deficits as well as postrestraint hyperthermia. Taken in the context of prior work, these data suggest that age-related loss of sleep architecture stress sensitivity may precede both cognitive and body temperature-related stress insensitivity.
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Affiliation(s)
- Kendra Hargis
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Heather M Buechel
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Jelena Popovic
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Eric M Blalock
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, USA.
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6
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Leakey JEA, Seng JE, Barnas CR, Baker VM, Hart RW. A Mechanistic Basis for the Beneficial Effects of Caloric Restriction On Longevity and Disease: Consequences for the Interpretation of Rodent Toxicity Studies. Int J Toxicol 2016. [DOI: 10.1177/109158189801700203] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Caloric restriction in rodents has been repeatedly shown to increase life span while reducing the severity and retarding the onset of both spontaneous and chemically induced neoplasms. These effects of caloric restriction are associated with a spectrum of biochemical and physiological changes that characterize the organism's adaptation to reduced caloric intake and provide the mechanistic basis for caloric restriction's effect on longevity. Here, we review evidence suggesting that the primary adaptation appears to be a rhythmic hypercorticism in the absence of elevated adrenocorticotropin (ACTH) levels. This characteristic hypercorticism evokes a spectrum of responses, including reduced body temperature and increased metabolic efficiency, decreased mitogenic response coupled with increased rates of apoptosis, reduced inflammatory response, reduced oxidative damage to proteins and DNA, reduced reproductive capacity, and altered drug-metabolizing enzyme expression. The net effect of these changes is to (1) decrease growth and metabolism in peripheral tissues to spare energy for central functions, and (2) increase the organism's capacity to withstand stress and chemical toxicity. Thus, caloric restriction research has uncovered an evolutionary mechanism that provides rodents with an adaptive advantage in conditions of fluctuating food supply. During periods of abundance, body growth and fecundity are favored over endurance and longevity. Conversely, during periods of famine, reproductive performance and growth are sacrificed to ensure survival of individuals to breed in better times. This phenomena can be observed in rodent populations that are used in toxicity testing. Improvements over the last 30 years in animal husbandry and nutrition, coupled with selective breeding for growth and fecundity, have resulted in several strains now exhibiting larger animals with reduced survival and increased incidence of background lesions. The mechanistic data from caloric restriction studies suggest that these large animals will also be more susceptible to chemically induced toxicity. This creates a problem in comparing tests performed on animals of different weights and comparing data generated today with the historical database. The rational use of caloric restriction to control body weight to within preset guidelines is a possible way of alleviating this problem.
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Affiliation(s)
- Julian E. A. Leakey
- Office of Research, National Center for Toxicological
Research, Jefferson, Arkansas, USA
| | - John E. Seng
- Office of Research, National Center for Toxicological
Research, Jefferson, Arkansas, USA
| | - Crissy R. Barnas
- Office of Research, National Center for Toxicological
Research, Jefferson, Arkansas, USA, Department of Clinical Pharmacology and Geriatrics,
Northwestern University, 303 E. Superior St., Chicago, IL 60611, USA
| | - Vanessa M. Baker
- Office of Research, National Center for Toxicological
Research, Jefferson, Arkansas, USA
| | - Ronald W. Hart
- Office of Research, National Center for Toxicological
Research, Jefferson, Arkansas, USA
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7
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Chesnokova V, Pechnick RN, Wawrowsky K. Chronic peripheral inflammation, hippocampal neurogenesis, and behavior. Brain Behav Immun 2016; 58:1-8. [PMID: 26802985 PMCID: PMC4956598 DOI: 10.1016/j.bbi.2016.01.017] [Citation(s) in RCA: 182] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Revised: 01/19/2016] [Accepted: 01/19/2016] [Indexed: 02/07/2023] Open
Abstract
Adult hippocampal neurogenesis is involved in memory and learning, and disrupted neurogenesis is implicated in cognitive impairment and mood disorders, including anxiety and depression. Some long-term peripheral illnesses and metabolic disorders, as well as normal aging, create a state of chronic peripheral inflammation. These conditions are associated with behavioral disturbances linked to disrupted adult hippocampal neurogenesis, such as cognitive impairment, deficits in learning and memory, and depression and anxiety. Pro-inflammatory cytokines released in the periphery are involved in peripheral immune system-to-brain communication by activating resident microglia in the brain. Activated microglia reduce neurogenesis by suppressing neuronal stem cell proliferation, increasing apoptosis of neuronal progenitor cells, and decreasing survival of newly developing neurons and their integration into existing neuronal circuits. In this review, we summarize evolving evidence that the state of chronic peripheral inflammation reduces adult hippocampal neurogenesis, which, in turn, produces the behavioral disturbances observed in chronic inflammatory disorders. As there are no data available on neurogenesis in humans with chronic peripheral inflammatory disease, we focus on animal models and, in parallel, consider the evidence of cognitive disturbance and mood disorders in human patients.
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Affiliation(s)
- Vera Chesnokova
- Department of Medicine, Cedars Sinai Medical Center, Los Angeles, CA, United States.
| | - Robert N Pechnick
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific and Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA, United States
| | - Kolja Wawrowsky
- Department of Medicine, Cedars Sinai Medical Center, Los Angeles, CA, United States
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8
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Hau M, Casagrande S, Ouyang J, Baugh A. Glucocorticoid-Mediated Phenotypes in Vertebrates. ADVANCES IN THE STUDY OF BEHAVIOR 2016. [DOI: 10.1016/bs.asb.2016.01.002] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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9
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Veerawatananan B, Surakul P, Chutabhakdikul N. Maternal restraint stress delays maturation of cation-chloride cotransporters and GABAA receptor subunits in the hippocampus of rat pups at puberty. Neurobiol Stress 2015; 3:1-7. [PMID: 26844244 PMCID: PMC4730793 DOI: 10.1016/j.ynstr.2015.12.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 12/09/2015] [Indexed: 12/13/2022] Open
Abstract
The GABAergic synapse undergoes structural and functional maturation during early brain development. Maternal stress alters GABAergic synapses in the pup's brain that are associated with the pathophysiology of neuropsychiatric disorders in adults; however, the mechanism for this is still unclear. In this study, we examined the effects of maternal restraint stress on the development of Cation-Chloride Cotransporters (CCCs) and the GABAA receptor α1 and α5 subunits in the hippocampus of rat pups at different postnatal ages. Our results demonstrate that maternal restraint stress induces a transient but significant increase in the level of NKCC1 (Sodium–Potassium Chloride Cotransporter 1) only at P14, followed by a brief, yet significant increase in the level of KCC2 (Potassium-Chloride Cotransporter 2) at P21, which then decreases from P28 until P40. Thus, maternal stress alters NKCC1 and KCC2 ratio in the hippocampus of rat pups, especially during P14 to P28. Maternal restraint stress also caused biphasic changes in the level of GABAA receptor subunits in the pup's hippocampus. GABAA receptor α1 subunit gradually increased at P14 then decreased thereafter. On the contrary, GABAA receptor α5 subunit showed a transient decrease followed by a long-term increase from P21 until P40. Altogether, our study suggested that the maternal restraint stress might delay maturation of the GABAergic system by altering the expression of NKCC1, KCC2 and GABAA receptor α1 and α5 subunits in the hippocampus of rat pups. These changes demonstrate the dysregulation of inhibitory neurotransmission during early life, which may underlie the pathogenesis of psychiatric diseases at adolescence.
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Affiliation(s)
- Bovorn Veerawatananan
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Nakornpathom 73170, Thailand
| | - Pornprom Surakul
- Faculty of Allied Health Sciences, Burapha University, Chonburi 20131, Thailand
| | - Nuanchan Chutabhakdikul
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Nakornpathom 73170, Thailand
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10
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Haussmann MF, Heidinger BJ. Telomere dynamics may link stress exposure and ageing across generations. Biol Lett 2015; 11:20150396. [PMID: 26538535 PMCID: PMC4685533 DOI: 10.1098/rsbl.2015.0396] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 08/24/2015] [Indexed: 01/26/2023] Open
Abstract
Although exposure to stressors is known to increase disease susceptibility and accelerate ageing, evidence is accumulating that these effects can span more than one generation. Stressors experienced by parents have been reported to negatively influence the longevity of their offspring and even grand offspring. The mechanisms underlying these long-term, cross-generational effects are still poorly understood, but we argue here that telomere dynamics are likely to play an important role. In this review, we begin by surveying the current connections between stress and telomere dynamics. We then lay out the evidence that exposure to stressors in the parental generation influences telomere dynamics in offspring and potentially subsequent generations. We focus on evidence in mammalian and avian studies and highlight several promising areas where our understanding is incomplete and future investigations are critically needed. Understanding the mechanisms that link stress exposure across generations requires interdisciplinary studies and is essential to both the biomedical community seeking to understand how early adversity impacts health span and evolutionary ecologists interested in how changing environmental conditions are likely to influence age-structured population dynamics.
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Affiliation(s)
- Mark F Haussmann
- Department of Biology, Bucknell University, Lewisburg, PA 17837, USA
| | - Britt J Heidinger
- Biological Sciences Department, North Dakota State University, Stevens Hall, Fargo, ND 58108, USA
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11
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Khalsa DS. Stress, Meditation, and Alzheimer's Disease Prevention: Where The Evidence Stands. J Alzheimers Dis 2015; 48:1-12. [PMID: 26445019 PMCID: PMC4923750 DOI: 10.3233/jad-142766] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/26/2015] [Indexed: 12/19/2022]
Abstract
Although meditation is believed to be over five thousand years old, scientific research on it is in its infancy. Mitigating the extensive negative biochemical effects of stress is a superficially discussed target of Alzheimer's disease (AD) prevention, yet may be critically important. This paper reviews lifestyle and stress as possible factors contributing to AD and meditation's effects on cognition and well-being for reduction of neurodegeneration and prevention of AD. This review highlights Kirtan Kriya (KK), an easy, cost effective meditation technique requiring only 12 minutes a day, which has been successfully employed to improve memory in studies of people with subjective cognitive decline, mild cognitive impairment, and highly stressed caregivers, all of whom are at increased risk for subsequent development of AD. KK has also been shown to improve sleep, decrease depression, reduce anxiety, down regulate inflammatory genes, upregulate immune system genes, improve insulin and glucose regulatory genes, and increase telomerase by 43%; the largest ever recorded. KK also improves psycho-spiritual well-being or spiritual fitness, important for maintenance of cognitive function and prevention of AD. KK is easy to learn and practice by aging individuals. It is the premise of this review that meditation in general, and KK specifically, along with other modalities such as dietary modification, physical exercise, mental stimulation, and socialization, may be beneficial as part of an AD prevention program.
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Affiliation(s)
- Dharma Singh Khalsa
- Alzheimer’s Research and Prevention Foundation, Tucson, AZ, USA
- Department of Internal/Integrative Medicine, University of New Mexico School of Medicine, Albuquerque, NM, USA
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12
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Jaatinen K, Seltmann MW, Hollmén T, Atkinson S, Mashburn K, Öst M. Context dependency of baseline glucocorticoids as indicators of individual quality in a capital breeder. Gen Comp Endocrinol 2013; 191:231-8. [PMID: 23851039 DOI: 10.1016/j.ygcen.2013.06.022] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 06/17/2013] [Accepted: 06/23/2013] [Indexed: 11/23/2022]
Abstract
Identifying markers of individual quality is a central goal of life-history theory and conservation biology. The 'corticosterone (CORT)-fitness hypothesis' postulates that low fitness signals impaired ability to cope with the environment, resulting in elevated baseline CORT levels. CORT can, however, be negatively, positively or neutrally related to fitness, depending on the context. In order to clarify this controversial issue, we elucidate the utility of using baseline CORT as a correlate of individual fitness in incubating female eiders across variable environments. An increase in serum CORT with decreasing body condition was evident in older, more experienced breeders, while increased clutch mass was associated with elevated serum CORT in females breeding late in the season. For faecal CORT, the expected negative association with body condition was observed only in early breeders. We found a strong increase in faecal CORT with increasing baseline body temperature, indicating the utility of body temperature as a complementary stress indicator. Females in good body condition had a lower baseline body temperature, but this effect was only observed on open islands, a harsher breeding habitat less buffered against weather variability. Females with higher reproductive investment also maintained a lower baseline body temperature. Nest success strongly decreased with increasing serum and faecal CORT concentrations, and individual stress hormone and body temperature profiles were repeatable over years. Although our data support the tenet that baseline CORT is negatively related to fitness, the complex context-dependent effects call for cautious interpretation of relationships between stress physiology and phenotypic quality.
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Affiliation(s)
- Kim Jaatinen
- Evolution, Ecology & Genetics, Research School of Biology, ANU College of Medicine, Biology & Environment, The Australian National University, Canberra ACT 0200, Australia.
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13
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Vitousek MN, Romero LM. Stress responsiveness predicts individual variation in mate selectivity. Gen Comp Endocrinol 2013; 187:32-8. [PMID: 23524274 DOI: 10.1016/j.ygcen.2013.03.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 02/06/2013] [Accepted: 03/04/2013] [Indexed: 11/28/2022]
Abstract
Steroid hormones, including glucocorticoids, mediate a variety of behavioral and physiological processes. Circulating hormone concentrations vary substantially within populations, and although hormone titers predict reproductive success in several species, little is known about how individual variation in circulating hormone concentrations is linked with most reproductive behaviors in free-living organisms. Mate choice is an important and often costly component of reproduction that also varies substantially within populations. We examined whether energetically costly mate selection behavior in female Galápagos marine iguanas (Amblyrhynchus cristatus) was associated with individual variation in the concentrations of hormones previously shown to differ between reproductive and non-reproductive females during the breeding season (corticosterone and testosterone). Stress-induced corticosterone levels - which are suppressed in female marine iguanas during reproduction - were individually repeatable throughout the seven-week breeding period. Mate selectivity was strongly predicted by individual variation in stress-induced corticosterone: reproductive females that secreted less corticosterone in response to a standardized stressor assessed more displaying males. Neither baseline corticosterone nor testosterone predicted variation in mate selectivity. Scaled body mass was not significantly associated with mate selectivity, but females that began the breeding period in lower body condition showed a trend towards being less selective about potential mates. These results provide the first evidence that individual variation in the corticosterone stress response is associated with how selective females are in their choice of a mate, an important contributor to fitness in many species. Future research is needed to determine the functional basis of this association, and whether transient acute increases in circulating corticosterone directly mediate mate choice behaviors.
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Affiliation(s)
- Maren N Vitousek
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA.
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14
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Kizaki T, Suzuki K, Ookawara T, Izawa T, Saitoh D, Oh-Ishi S, Suzuki K, Haga S, Ohno H. Stress- and aging-associated modulation of macrophage functions. Environ Health Prev Med 2012; 6:218-28. [PMID: 21432338 DOI: 10.1007/bf02897973] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2001] [Accepted: 11/16/2001] [Indexed: 01/13/2023] Open
Abstract
Effects of environmental (cold) stress and aging on cells in monocyte/macrophage lineage were investigated. We demonstrated that immune suppressive states seen in acute cold-stressed mice (8-10 weeks of age) is attributable to FcγRII(bright) suppressor macrophages. Serum corticosterone levels were markedly increased in acute cold-stressed mice. In addition, expression of glucocorticoids (GC) receptor mRNA was observed in FcγRII(bright) cells from these mice. The increase of FcγRII(bright) cells in peritoneal exudate cells caused by acute cold stress was inhibited by adrenalectomy or administration of a saturating amount of the GC antagonist RU 38486 (mifepristone). On the contrary, administration of the GC agonist, dexamethasone, markedly increased the proportion of FcγRII(bright) cells in peritoneal exudate cells of control mice. These results suggest that the generation of FcγRII(bright) suppressor cells of monocyte/macrophage lineage by acute cold stress was mediated by action of GC through the GC receptor. We likewise found that the proportion of FcγRII(bright) suppressor macrophages is increased in aged mice (22-24 months of age). Meanwhile, activated macrophages which function as antigen presenting cells were decreased in aged rats. Both the basal corticosterone concentrations in serum and the expression of mRNA for GC receptor in peritoneal macrophages increased significantly in aged animals, suggesting that these populational and functional changes of macrophages in aged animals were mediated, in part, by the increased basal levels of GC. This is probably being responsible for immunosenescence.
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Affiliation(s)
- Takako Kizaki
- Department of Molecular Predictive Medicine and Sport Science, Kyorin University, School of Medicine, 6-20-2, Shinkawa, Mitaka, 181-8611, Tokyo, Japan,
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15
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Stress responsiveness, age and body condition interactively affect flight initiation distance in breeding female eiders. Anim Behav 2012. [DOI: 10.1016/j.anbehav.2012.07.012] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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McConnachie SH, Cook KV, Patterson DA, Gilmour KM, Hinch SG, Farrell AP, Cooke SJ. Consequences of acute stress and cortisol manipulation on the physiology, behavior, and reproductive outcome of female Pacific salmon on spawning grounds. Horm Behav 2012; 62:67-76. [PMID: 22580596 DOI: 10.1016/j.yhbeh.2012.05.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 04/30/2012] [Accepted: 05/02/2012] [Indexed: 11/16/2022]
Abstract
Life-history theory predicts that stress responses should be muted to maximize reproductive fitness. Yet, the relationship between stress and reproduction for semelparous salmon is unusual because successfully spawning individuals have elevated plasma cortisol levels. To tease apart the effects of high baseline cortisol levels and stress-induced elevation of cortisol titers, we determined how varying degrees of cortisol elevation (i.e., acute and chronic) affected behavior, reproductive physiology, and reproductive success of adult female pink salmon (Oncorhynchus gorbuscha) relative to different states of ovulation (i.e., ripe and unripe). Exhaustive exercise and air exposure were applied as acute stressors to manipulate plasma cortisol in salmon either confined to a behavioral arena or free-swimming in a spawning channel. Cortisol (eliciting a cortisol elevation to levels similar to those in post-spawn female salmon) and metyrapone (a corticosteroid synthesis inhibitor) implants were also used to chemically manipulate plasma cortisol. Cortisol implants elevated plasma cortisol, and impaired reproductive success; cortisol-treated fish released fewer eggs and died sooner than fish in other treatment groups. In contrast, acute stressors elevated plasma cortisol and the metyrapone implant suppressed plasma cortisol, but neither treatment significantly altered reproductive success, behavior, or physiology. Our results suggest that acute stressors do not influence behavior or reproductive outcome when experienced upon arrival at spawning grounds. Thus, certain critical aspects of salmonid reproduction can become refractory to various stressful conditions on spawning grounds. However, there is a limit to the ability of these fish to tolerate elevated cortisol levels as revealed by experimental elevation of cortisol.
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Affiliation(s)
- Sarah H McConnachie
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, Canada K1S 5B6.
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Senemorphism: a novel perspective on aging patterns and its implication for diet-related biology. Biogerontology 2012; 13:457-66. [PMID: 22555514 PMCID: PMC3407360 DOI: 10.1007/s10522-012-9383-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 04/20/2012] [Indexed: 01/08/2023]
Abstract
Aging can be described as the accumulation of changes in organisms over time. Aging in organisms undergoing caloric restriction (CR) is widely considered as a slowed version of aging under ad libitum (AL) conditions. However, here we argue that aging under optimized CR is fundamentally different from aging under AL based on the following facts: (1) Comparing the two dietary groups, several age-related changes run in the opposite direction over time; (2) Switching from an AL to a CR diet clearly reverts (not only delays) several "normal" accumulated changes; (3) major causes of death are as different between both groups as they are between species. These observations support the idea that CR and AL initially modulate different metabolic and physiological programs, which exclusively over time generate two biologically different organisms. Such distinct diet-related senescence is analogous to the divergent aging processes and causes of death observed between castes of social insects, such as queens versus workers ("caste-related-senescence") and also between breeding versus non-breeding semelparous animals ("reproduction-related-senescence"). All these aging phenotypes are different not because they accumulate changes at a different rate, but because they accumulate different changes over time. Thus, the environment does not simply affect the individual aging rate through stochastic effects (e.g. U.V.) but also modulates the activation of a particular program/strategy that influences lifespan (e.g. caste, calorie intake). We refer to the environment-dependent aging patterns encoded by the genome as "senemorphism". Based on this idea we propose experimental schemes for aging, evolution and biomedical research.
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18
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Khalsa DS. Alzheimer Disease. Integr Med (Encinitas) 2012. [DOI: 10.1016/b978-1-4377-1793-8.00009-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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19
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Wilcoxen TE, Boughton RK, Bridge ES, Rensel MA, Schoech SJ. Age-related differences in baseline and stress-induced corticosterone in Florida scrub-jays. Gen Comp Endocrinol 2011; 173:461-6. [PMID: 21827761 DOI: 10.1016/j.ygcen.2011.07.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 06/22/2011] [Accepted: 07/22/2011] [Indexed: 11/17/2022]
Abstract
In physiological studies of free-living species, it is essential to consider the context of the life history stage at which an individual was observed in order to link measures of physiology with ecological parameters. One such measure that is important to consider is the age of an individual. We tested whether baseline or stress-induced corticosterone levels vary with age in free-living Florida scrub-jays (Aphelocoma coerulescens) during the pre-breeding period. Corticosterone (CORT), the primary avian stress hormone, is released in response to stressful stimuli, and stimulates gluconeogenesis; however, it also serves as a chemical messenger that can influence other physiological processes, reproduction, and behavior. We monitored both baseline CORT levels longitudinally throughout a five-year period and stress-induced CORT responses over a shorter two-year period. We predicted that older jays would have lower baseline CORT levels and a dampened stress response compared to younger birds, as has been shown in other avian species. We found no significant differences in baseline CORT levels with age. We found a decrease in total corticosterone responses to a stressor with age, however, the oldest birds in the population showed greater total corticosterone responses to a stressor. These results may be a product of age-related changes in physiological processes related to the stress response or a result of selection acting on the population, resulting in only the most responsive individuals surviving to old age.
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Affiliation(s)
- Travis E Wilcoxen
- Department of Biological Sciences, University of Memphis, Memphis, TN 38152, USA.
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20
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Hruska KA, Hinch SG, Healey MC, Patterson DA, Larsson S, Farrell AP. Influences of sex and activity level on physiological changes in individual adult sockeye salmon during rapid senescence. Physiol Biochem Zool 2010; 83:663-76. [PMID: 20482369 DOI: 10.1086/652411] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
A noninvasive biopsy protocol was used to sample plasma and gill tissue in individual sockeye salmon (Oncorhynchus nerka) during the critical life stage associated with spawning-arrival at a spawning channel through senescence to death several days later. Our main objective was to characterize the physiological changes associated with rapid senescence in terms of the physiological stress/cortisol hypersecretion model and the energy exhaustion model. Salmon lived an average of 5 d in the spawning channel, during which time there were three major physiological trends that were independent of sexual status: a large increase in plasma indicators of stress and exercise (i.e., lactate and cortisol), a decrease in the major plasma ions (i.e., Cl(-) and Na(+)) and osmolality, and a decrease in gross somatic energy reserves. Contrary to a generalized stress response, plasma glucose decreased in approximately 2/3 of the fish after arrival, as opposed to increasing. Furthermore, plasma cortisol levels at spawning-ground arrival were not correlated with the degree of ionoregulatory changes during rapid senescence. One mechanism of mortality in some fish may involve the exhaustion of energy reserves, resulting in the inability to mobilize plasma glucose. Sex had a significant modulating effect on the degree of physiological change. Females exhibited a greater magnitude of change for gross somatic energy, osmolality, and plasma concentrations of Cl(-), Na(+), cortisol, testosterone, 11-ketotestosterone, 17,20beta-progesterone, and estradiol. The activity level of an individual on the spawning grounds appeared to influence the degree of some physiological changes during senescence. For example, males that received a greater frequency of attacks exhibited larger net decreases in plasma 11-ketotestosterone while on the spawning grounds. These results suggest that rapid senescence on spawning grounds is influenced by multiple physiological processes and perhaps behavior. This study provides some of the first data to look at sex differences in senescence in Pacific salmon.
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Affiliation(s)
- Kimberly A Hruska
- Centre for Applied Conservation Research and Department of Forest Sciences, University of British Columbia, Vancouver, BC
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21
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Heidinger BJ, Chastel O, Nisbet ICT, Ketterson ED. Mellowing with age: older parents are less responsive to a stressor in a long-lived seabird. Funct Ecol 2010. [DOI: 10.1111/j.1365-2435.2010.01733.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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22
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Von Dras DD, Blumenthal HT. Biological, Social-Environmental, and Psychological Dialecticism: An Integrated Model of Aging. BASIC AND APPLIED SOCIAL PSYCHOLOGY 2010. [DOI: 10.1207/s15324834basp2203_7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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23
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Barry TP, Marwah A, Nunez S. Inhibition of cortisol metabolism by 17alpha,20beta-P: mechanism mediating semelparity in salmon? Gen Comp Endocrinol 2010; 165:53-9. [PMID: 19523470 DOI: 10.1016/j.ygcen.2009.06.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2008] [Revised: 04/13/2009] [Accepted: 06/02/2009] [Indexed: 11/19/2022]
Abstract
In vitro experiments were conducted to test the hypothesis that 17alpha,20beta-dihydroxy-4-prengnen-3-one (17,20-P) regulates cortisol metabolism in Pacific salmon. In both rainbow trout and coho salmon, cortisol metabolism was significantly higher in the kidney compared to the liver. The rainbow trout kidney converted cortisol primarily into an unidentified water-soluble metabolite with a molecular mass of 354. The coho salmon kidney converted cortisol primarily into cortisol-21-sulfate. High physiological concentrations of 17,20-P had no effect on cortisol metabolism by the rainbow trout kidney, but almost completely inhibited the production of cortisol-21-sulfate by the coho salmon kidney. This was accompanied by a coincident increase in the production several neutral cortisol metabolites, including cortisone. Cortisone was also found to inhibit renal sulfotransferase (SULT) activity suggesting that there could be a local positive feedback mechanism initiated by the rise in 17,20-P that quickly reduces SULT activity as follows: the pre-spawning rise in 17,20-P inhibits SULT, cortisol is metabolized to cortisone instead of cortisol-21-sulfate, cortisone further inhibits SULT, more cortisone is produced, and so on. If SULT normally acts as a gatekeeper enzyme to protect the cell from cortisol excess, this mechanism would rapidly remove enzymatic protection and expose tissues to high local concentrations of cortisol. In addition, the inhibition of peripheral cortisol metabolism by 17,20-P could increase circulating concentrations of the corticosteroid. These events could be a part of the mechanism that leads to the symptoms of cortisol excess associated with the post-spawning mortality of semelparous Pacific salmon.
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Affiliation(s)
- Terence P Barry
- Department of Animal Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA.
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24
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Heidinger BJ, Nisbet IC, Ketterson ED. Changes in adrenal capacity contribute to a decline in the stress response with age in a long-lived seabird. Gen Comp Endocrinol 2008; 156:564-8. [PMID: 18378235 DOI: 10.1016/j.ygcen.2008.02.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2007] [Revised: 02/16/2008] [Accepted: 02/22/2008] [Indexed: 11/24/2022]
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25
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p21Cip1 restricts neuronal proliferation in the subgranular zone of the dentate gyrus of the hippocampus. Proc Natl Acad Sci U S A 2008; 105:1358-63. [PMID: 18172194 DOI: 10.1073/pnas.0711030105] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The subgranular zone (SGZ) of the dentate gyrus of the hippocampus is a brain region where robust neurogenesis continues throughout adulthood. Cyclin-dependent kinases (CDKs) have a primary role in controlling cell division and cellular proliferation. p21(Cip1) (p21) is a CDK inhibitor that restrains cell cycle progression. Confocal microscopy revealed that p21 is abundantly expressed in the nuclei of cells in the SGZ and is colocalized with NeuN, a marker for neurons. Doublecortin (DCX) is a cytoskeletal protein that is primarily expressed by neuroblasts. By using FACS analysis it was found that, among DCX-positive cells, 42.8% stained for p21, indicating that p21 is expressed in neuroblasts and in newly developing neurons. p21-null (p21(-/-)) mice were examined, and the rate of cellular proliferation, as measured by BrdU incorporation, was increased in the SGZ of p21(-/-) compared with WT mice. In addition, the levels of both DCX and NeuN protein were increased in p21(-/-) mice, further demonstrating increased hippocampal neuron proliferation. Chronic treatment with the tricyclic antidepressant imipramine (10 mg/kg per day i.p. for 21 days) markedly decreased hippocampal p21 mRNA and protein levels, produced antidepressant-like behavioral changes in the forced swim test, and stimulated neurogenesis in the hippocampus. These results suggest that p21 restrains neurogenesis in the SGZ and imipramine-induced stimulation of neurogenesis might be a consequence of decreased p21 expression and the subsequent release of neuronal progenitor cells from the blockade of proliferation. Because many antidepressants stimulate neurogenesis, it is possible that their shared common mechanism of action is suppression of p21.
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Schmidt AL, Taggart DA, Holz P, Temple-Smith PD, Bradley AJ. Plasma steroids and steroid-binding capacity in male semelparous dasyurid marsupials (Phascogale tapoatafa) that survive beyond the breeding season in captivity. Gen Comp Endocrinol 2006; 149:236-43. [PMID: 16884721 DOI: 10.1016/j.ygcen.2006.06.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2006] [Revised: 05/28/2006] [Accepted: 06/08/2006] [Indexed: 11/16/2022]
Abstract
The semelparous dasyurids display a unique life history, in that all males die within a few weeks of the completion of the breeding season. Studies of several semelparous species have revealed that the male die-off is stress-related, and accompanied by increased plasma androgen and cortisol levels and decreased corticosteroid binding capacity, resulting in suppression of immune and inflammatory responses. This study examines the endocrine profile of male brush-tailed phascogales (Phascogale tapoatafa) that survive beyond the breeding season in captivity. Plasma cortisol, corticosteroid binding globulin and albumin levels were monitored in both males and females and steroid partitioning calculated. Captive males surviving beyond the breeding season did not show the elevation in plasma cortisol and decrease in corticosteroid binding capacity reported in wild males. Plasma albumin concentrations also remained constant during the sampling period. These data indicate that captive males do not undergo the same stress response described in wild populations.
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Affiliation(s)
- A L Schmidt
- Department of Anatomical Sciences, School of Biomedical Sciences, The University of Queensland, St. Lucia, Qld 4072, Australia
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27
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Heidinger BJ, Nisbet IC, Ketterson ED. Older parents are less responsive to a stressor in a long-lived seabird: a mechanism for increased reproductive performance with age? Proc Biol Sci 2006; 273:2227-31. [PMID: 16901843 PMCID: PMC1635515 DOI: 10.1098/rspb.2006.3557] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In many taxa, reproductive performance increases throughout the lifespan and this may occur in part because older adults invest more in reproduction. The mechanisms that facilitate an increase in reproductive performance with age, however, are poorly understood. In response to stressors, vertebrates release glucocorticoids, which enhance survival but concurrently shift investment away from reproduction. Consequently, when the value of current reproduction is high relative to the value of future reproduction and survival, as it is in older adults, life history theory predicts that the stress response should be suppressed. In this study, we tested the hypothesis that older parents would respond less strongly to a stressor in a natural, breeding population of common terns (Sterna hirundo). Common terns are long-lived seabirds and reproductive performance is known to increase throughout the lifespan of this species. As predicted, the maximum level of glucocorticoids released in response to handling stress decreased significantly with age. We suggest that suppression of the stress response may be an important physiological mechanism that facilitates an increase in reproductive performance with age.
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Affiliation(s)
- Britt J Heidinger
- Department of Biology, Indiana UniversityBloomington, IN 47405, USA
- Center for the Integrative Study of Animal Behaviour, Indiana UniversityBloomington, IN 47405, USA
- Author and address for correspondence: Department of Biology, Indiana University, 1001 East 3rd Street, Bloomington, IN 47405, USA ()
| | - Ian C.T Nisbet
- I. C. T. Nisbet & Company150 Alder Lane, North Falmouth, MA 02556, USA
| | - Ellen D Ketterson
- Department of Biology, Indiana UniversityBloomington, IN 47405, USA
- Center for the Integrative Study of Animal Behaviour, Indiana UniversityBloomington, IN 47405, USA
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28
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Liu HH, Payne HR, Wang B, Brady ST. Gender differences in response of hippocampus to chronic glucocorticoid stress: role of glutamate receptors. J Neurosci Res 2006; 83:775-86. [PMID: 16498614 DOI: 10.1002/jnr.20782] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Glucocorticoids (GC) play critical roles in the pathophysiological reactions to environmental stress. In brain, morphological changes were examined in hippocampal CA3 neurons with 2 weeks of chronic elevation of GC in male and female mice. Molecular correlates and underlying mechanisms paralleling these morphologic changes in hippocampus were investigated. Although the hippocampal neurons in the CA3 area in male mice atrophy with chronically elevated GC, female mice show minimal morphological changes with comparable GC regimens. These sexual morphological differences correlate with differences in the postsynaptic dense protein (PSD95) as well as the spectrum of glutamate receptors induced by GC treatment in male and female mice, including NMDA, AMPA, and KA receptors. These findings suggest that synaptic receptor composition is adapted to the unique physiological requirements of males and females and illuminate underlying mechanisms of GC/stress responses in the brain.
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Affiliation(s)
- Howard H Liu
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Illinois 60612, USA
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29
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Raouf SA, Smith LC, Brown MB, Wingfield JC, Brown CR. Glucocorticoid hormone levels increase with group size and parasite load in cliff swallows. Anim Behav 2006. [DOI: 10.1016/j.anbehav.2005.03.027] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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30
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Morbey YE, Brassil CE, Hendry AP. Rapid Senescence in Pacific Salmon. Am Nat 2005; 166:556-68. [PMID: 16224721 DOI: 10.1086/491720] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2004] [Accepted: 07/19/2005] [Indexed: 11/04/2022]
Abstract
Any useful evolutionary theory of senescence must be able to explain variation within and among natural populations and species. This requires a careful characterization of age-specific mortality rates in nature as well as the intrinsic and extrinsic factors that influence these rates. We perform this task for two populations of semelparous Pacific salmon. During the breeding season, estimated daily mortality rates increased from 0 to 0.2-0.5 (depending on the year) over the course of several weeks. Early-arriving individuals had a later onset and/or a lower rate of senescence in each breeding season, consistent with adaptive expectations based on temporal variation in selection. Interannual variation in senescence was large, in part because of extrinsic factors (e.g., water temperature). Predation rates were higher in Pick Creek sockeye salmon (anadromous Oncorhynchus nerka) than in Meadow Creek kokanee (nonanadromous O. nerka), but in contrast to evolutionary theory, senescence was not more rapid in the former. Interannual variation may have obscured interpopulation divergence in senescence. Pacific salmon are a promising system for further studies on the physiological, evolutionary, and genetic bases of senescence. In particular, we encourage further research to disentangle the relative importance of adaptive and nonadaptive variation in senescence.
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Affiliation(s)
- Yolanda E Morbey
- Department of Zoology, Ramsay Wright Zoological Laboratories, University of Toronto, 25 Harbord Street, Toronto, Ontario M5S 3G5, Canada.
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31
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Brunson KL, Baram TZ, Bender RA. Hippocampal neurogenesis is not enhanced by lifelong reduction of glucocorticoid levels. Hippocampus 2005; 15:491-501. [PMID: 15744738 PMCID: PMC2921196 DOI: 10.1002/hipo.20074] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Neurogenesis of dentate gyrus granule cells is generally considered to be negatively regulated by glucocorticoids. We tested the hypothesis that exposure to low plasma corticosteroid levels starting in the early postnatal period enhances granule cell proliferation rate during adulthood. Rat pups were adrenalectomized (ADX) on postnatal day 10 and were then "clamped" throughout life at low corticosterone levels via oral supplementation. Neurogenesis was determined using BrdU immunochemistry at 3 and 12 months in clamped rats as compared with age-matched, sham-operated controls. Rate of neurogenesis did not differ between the groups at either 3 or 12 months. It was significantly lower in 12-month-old compared with 3-month-old rats, despite the presence of an age-dependent increase of plasma corticosterone only in the sham-ADX rats. Granule cell layer volume, granule cell density, and granule cell degeneration (determined using apoptotic markers) were indistinguishable in the two groups, further supporting the comparable rate of neurogenesis under differing chronic glucocorticoid levels. In addition, whereas acute deprivation of plasma glucocorticoids (adrenalectomy) in adult rats evoked a burst of granule cell neurogenesis, complete elimination of these hormones (by stopping hormone supplementation) in adult, early-life ADX/clamped rats did not. These data do not support a simple inverse relationship between chronic plasma glucocorticoid levels and granule cell neurogenesis. Specifically, chronic modulation of glucocorticoid levels commencing early in life evokes additional, adaptive, and compensatory mechanisms that contribute to the regulation of granule cell proliferation.
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Affiliation(s)
- Kristen L. Brunson
- Departments of Anatomy/Neurobiology and Pediatrics, University of California, Irvine, California
| | - Tallie Z. Baram
- Departments of Anatomy/Neurobiology and Pediatrics, University of California, Irvine, California
| | - Roland A. Bender
- Departments of Anatomy/Neurobiology and Pediatrics, University of California, Irvine, California
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32
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Guayerbas N, De La Fuente M. An impairment of phagocytic function is linked to a shorter life span in two strains of prematurely aging mice. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2003; 27:339-350. [PMID: 12590967 DOI: 10.1016/s0145-305x(02)00103-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In previous cross-sectional studies on Swiss mouse populations we have shown that at the same chronological age, animals that take longer to explore a simple T-maze (slow mice) are hyper-emotional and show an impairment of the immune system than those which quickly explore the maze (fast mice). Therefore, we have proposed that the slow mice are a model of prematurely aging mice (PAM). In the present work we have carried out a longitudinal study of age-dependent changes in key functions of phagocytic cells (peritoneal macrophages) such as phagocytosis and superoxide anion production in both male and female Swiss (outbred strain) and BALB/c (inbred strain) PAM and non-prematurely aging mice (NPAM). Gender differences were found showing the females better phagocytic and digestion capacities with concomitant longer life span. The PAM showed an impaired phagocytosis capacity and intracellular superoxide anion production as well as an increase of its extracellular production as compared to NPAM, which could be related to the shortened life span of those animals in both sexes and strains.
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Affiliation(s)
- Noelia Guayerbas
- Department of Animal Physiology, Faculty of Biology, Complutense University, Jose Antonio Novais s/n, Madrid, Spain
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33
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Abstract
This review will highlight recent advances in the study of the immuno-endocrinology of the testis, in particular how macrophage-derived inflammatory mediators affect Leydig cell functions. Both the beneficial and deleterious outcomes resulting from macrophage-Leydig cell interactions are discussed. A brief overview of testicular physiology is provided that discusses the functional and anatomical compartmentalization of the testis into the gamete and endocrine compartments where spermatogenesis and testosterone biosynthesis take place, respectively. The process of steroidogenesis including the activities of the steroidogenic enzymes and the role of steroidogenic acute regulatory protein (StAR) are described. The close physical association between Leydig cells and interstitial testicular macrophages suggests that these cells are functionally related. Under normal physiological and non-inflammatory conditions macrophages play an important role in Leydig cell development. If macrophages are absent from the testicular interstitium, Leydig cells fail to develop normally, which suggest that macrophages provide essential growth and differentiation factors for Leydig cells. In contrast, when macrophages are activated and elaborate inflammatory mediators, Leydig cell steroidogenesis is inhibited. Activated macrophages produce pro-inflammatory cytokines such as interleukin-1 (IL-1) and tumor necrosis factor (TNF) that are profoundly inhibitory to Leydig cells and appear to act as transcriptional repressors of steroidogenic enzyme gene expression. Macrophages also produce reactive oxygen species (ROS) such as hydrogen peroxide, which also inhibits Leydig cell functions. ROS appear to act acutely by perturbing Leydig cell mitochondria resulting in the inhibition of StAR protein expression. One important consequence of this immune modulation of Leydig cell function may be manifest behaviorally by switching the affected animal from 'testosterone' behavior, to 'sickness' behavior. Increased interest in immune-endocrine control of reproductive function over the past decade has stimulated research into the molecular and biochemical immunopathophysiology of the reproductive system. As investigations unravel mechanisms underlying reproductive dysfunction caused by inflammation and infection, an understanding of the role that immune-endocrine interactions play in the normal physiology of the reproductive system has emerged.
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Affiliation(s)
- Dale Buchanan Hales
- Department of Physiology and Biophysics (M/C901), University of Illinois at Chicago, Chicago, IL 60612-7342, USA.
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34
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Guayerbas N, Catalán M, Víctor VM, Miquel J, De la Fuente M. Relation of behaviour and macrophage function to life span in a murine model of premature immunosenescence. Behav Brain Res 2002; 134:41-8. [PMID: 12191790 DOI: 10.1016/s0166-4328(01)00449-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
According to our previous work, mice of the same strain and age show striking inter-individual differences in behaviour when exposed to a T-maze test. Further, the animals exploring the maze slowly (slow mice) or staying at the starting point (freezing behaviour), which show high levels of emotionality/anxiety in other standard behavioural tests, have a less competent immune system (earlier immunosenescence) than those which explore it quickly (fast mice). The present longitudinal study on OF-1 Swiss female mice confirms and extends the above findings. Thus, the animals showing a lower performance in the T-test (slow mice) which is accompanied by a poor neuromuscular coordination in a tightrope test, have a shorter life span than the good performers (fast mice). Moreover, the slow mice have a less competent immune system as regards the following functions of peritoneal macrophages: adherence to substrate, chemotaxis, ingestion of particles and superoxide anion production. This suggests that, at the same chronological age and as regards their immune competence, the slow mice are biologically older than the fast mice. This agrees with current ideas on the close functional relationship between the nervous and the immune system in the physiological adaptation to stress, and supports the concept that an optimum level of performance of these two systems is needed to attain a long life span.
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Affiliation(s)
- Noelia Guayerbas
- Department of Animal Physiology, Faculty of Biological Sciences, Complutense University, Madrid E-28040, Spain
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35
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Guayerbas N, Puerto M, Víctor VM, Miquel J, De la Fuente M. Leukocyte function and life span in a murine model of premature immunosenescence. Exp Gerontol 2002; 37:249-56. [PMID: 11772510 DOI: 10.1016/s0531-5565(01)00190-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Aging associates with a decline of physiological functions, including the function of the nervous and the immune system. These aged-related changes occur in various degrees in different members of a mouse outbred population. Accordingly, we have proposed a model of premature immunosenescence in mice, based on the demonstration of premature decline in the behavioral response in a simple T-maze and in several immune functions in Swiss outbred mice. Those mice with a worst (slow) performance in this test (linked to a higher emotional response to stress) show a shorter life span and a decreased immune function when compared to fast mice. In order to provide biomarkers of "biological aging" related to health and survival, the present longitudinal study includes the analysis of several immunological parameters such as, proliferative response to mitogen Con A, NK activity and cytokine (TNFalpha, IL-1beta and IL-2) release by peritoneal leukocytes from female Swiss mice. Slow mice showed a lower proliferative response to Con A, IL-2 and IL-1beta release, an impaired NK activity and an increased TNFalpha production as compared to fast mice. Moreover, the age-associated decline of these functions is more strikingly slow than in fast mice. In summary, we propose the above immunological parameters, that change with aging at a different rate in members of a same population, as useful biomarkers to asses the rate of biological aging in mice.
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Affiliation(s)
- N Guayerbas
- Department of Animal Physiology, Faculty of Biological Sciences, Complutense University, 28040 Madrid, Spain
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KIZAKI T, SUZUKI K, OOKAWARA T, IZAWA T, SAITOH D, OH-ISHI S, SUZUKI K, HAGA S, OHNO H. Stress- and Aging-Associated Modulation of Macrophage Functions. Environ Health Prev Med 2002. [DOI: 10.1265/ehpm.2001.218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Sapolsky RM, Romero LM, Munck AU. How do glucocorticoids influence stress responses? Integrating permissive, suppressive, stimulatory, and preparative actions. Endocr Rev 2000; 21:55-89. [PMID: 10696570 DOI: 10.1210/edrv.21.1.0389] [Citation(s) in RCA: 1590] [Impact Index Per Article: 66.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The secretion of glucocorticoids (GCs) is a classic endocrine response to stress. Despite that, it remains controversial as to what purpose GCs serve at such times. One view, stretching back to the time of Hans Selye, posits that GCs help mediate the ongoing or pending stress response, either via basal levels of GCs permitting other facets of the stress response to emerge efficaciously, and/or by stress levels of GCs actively stimulating the stress response. In contrast, a revisionist viewpoint posits that GCs suppress the stress response, preventing it from being pathologically overactivated. In this review, we consider recent findings regarding GC action and, based on them, generate criteria for determining whether a particular GC action permits, stimulates, or suppresses an ongoing stress-response or, as an additional category, is preparative for a subsequent stressor. We apply these GC actions to the realms of cardiovascular function, fluid volume and hemorrhage, immunity and inflammation, metabolism, neurobiology, and reproductive physiology. We find that GC actions fall into markedly different categories, depending on the physiological endpoint in question, with evidence for mediating effects in some cases, and suppressive or preparative in others. We then attempt to assimilate these heterogeneous GC actions into a physiological whole.
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Affiliation(s)
- R M Sapolsky
- Department of Biological Sciences, Stanford University, California 94305, USA
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Carruth LL, Jones RE, Norris DO. Cell density and intracellular translocation of glucocorticoid receptor-immunoreactive neurons in the kokanee salmon (Oncorhynchus nerka kennerlyi) brain, with an emphasis on the olfactory system. Gen Comp Endocrinol 2000; 117:66-76. [PMID: 10620424 DOI: 10.1006/gcen.1999.7391] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study tested the hypothesis that neurons in olfactory regions of the kokanee salmon brain contain glucocorticoid receptors. Distribution and neuronal number of glucocorticoid receptor-like immunoreactive (GRir) neurons were identified in the kokanee salmon brain using immunohistochemistry with an antibody to GR (polyclonal rabbit anti-human, dilution 1:1500; and monoclonal mouse, dilution 5 micrograms/ml). Distribution of GRir neurons similar to the mammalian pattern was observed in the brains of sexually immature (n = 8; 4 female and 4 male) as well as spawning (n = 8; 4 female and 4 male) salmon. Olfactory-related areas containing GRir positive neuronal bodies included the internal cell layer of the olfactory bulb, ventral-lateral and lateral parts of the dorsal telencephalon (homologue of the mammalian hippocampus), ventral area of the telencephalon (homologue of the mammalian amygdala), glomerulosus complex of the thalamus, the preoptic area, and inferior lobe of the hypothalamus. The pattern of GRir neuronal distribution in sexually immature and spawning fish was similar. However, spawning fish brains, compared to sexually immature brains, exhibited a significantly greater GRir neuronal number in several olfactory regions in paired immunohistochemical runs. There also were differences in intraneuronal location of GRir in olfactory regions, with staining being predominantly cytoplasmic in sexually immature fish but nuclear in spawning fish. These results are consistent with a role for cortisol in olfactory-mediated homing in kokanee salmon. Although GRir were identified in many nonolfactory regions, the focus of this study is on GRir present in brain regions involved in olfaction.
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Affiliation(s)
- L L Carruth
- Department of Environmental, Population and Organismic Biology, University of Colorado, Boulder 80309, USA
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Abstract
Inflammatory disease has been established to affect male reproductive function and fertility. Relevant inflammatory diseases include general and chronic infectious diseases as well as localized acute or chronic infections of the male genitourinary tract. Male accessory gland infections account for almost 15% of all cases of male infertility seen in infertility clinics while fertility usually is not a clinical objective among patients with acute systemic infections such as Gram-negative sepsis. Infections of the male accessory glands frequently are associated with increased counts of white blood cells in semen and elevated levels of proinflammatory cytokines in semen and the testis. There is a mounting body of evidence that demonstrates the importance of cytokines and chemokines in the regulation of testicular and glandular function during pathophysiological states as well as under normal physiological conditions when cytokines act as growth and differentiation factors. The purpose of this review is to examine the role of cytokines in the regulation of steroidogenesis and spermatogenesis in the testis under physiological and pathophysiological conditions and considers clinical investigations that help to improve the evaluation and treatment of male infertility.
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Affiliation(s)
- D B Hales
- Department of Physiology and Biophysics, University of Illinois at Chicago, 60612-7342, USA.
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De la Fuente M, Miñano M, Manuel Victor V, Del Rio M, Ferrández MD, Díez A, Miquel J. Relation between exploratory activity and immune function in aged mice: a preliminary study. Mech Ageing Dev 1998; 102:263-77. [PMID: 9720657 DOI: 10.1016/s0047-6374(98)00015-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Previous studies show that fast exploration of a T-shaped maze by mature mice may predict an above average longevity. Since the nervous and the immune systems work in a coordinated fashion, and it seems that these two homeostatic systems both influence organismic aging and suffer a senescent decline, we have performed a comparative study of the above behavioral parameter and different functions of three representative immune cells: lymphocytes, macrophages and natural killer (NK) cells obtained from old (76 +/- 1 weeks of age) female OF1-Swiss mice. At 70 weeks of age the mice were divided into a 'fast' and a 'slow' group, containing 100 and 0%, respectively, of animals able to explore the 50 cm-long first arm of the maze in 20 s or less. At 76 +/- 1 weeks of age the animals were sacrificed, the peritoneal cell suspensions were obtained and the immune organs (axillary nodes, spleen and thymus) were isolated. The following leukocyte functions were studied in peritoneal macrophages: adherence to substrate, mobility (spontaneous and chemotaxis), ingestion of particles and superoxide anion production whereas mobility, lymphoproliferative response to the mitogen Con A and NK activity were studied in the immune-organ leukocyte suspensions. The results show that the aged fast mice have better immune functions than the aged slow mice.
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Affiliation(s)
- M De la Fuente
- Department of Animal Physiology, Faculty of Biological Sciences, Complutense University, Madrid, Spain.
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Kizaki T, Ookawara T, Oh-Ishi S, Itoh Y, Iwabuchi K, Onoé K, Day NK, Good RA, Ohno H. An increase in basal glucocorticoid concentration with age induces suppressor macrophages with high-density Fc gamma RII/III. Immunology 1998; 93:409-14. [PMID: 9640253 PMCID: PMC1364091 DOI: 10.1046/j.1365-2567.1998.00433.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ageing is usually accompanied by a decline in immune and neuroendocrine functions. To elucidate the mechanisms underlying age-related immunosuppression, the functions and surface phenotypes of peritoneal cells in the monocyte/macrophage lineage from old mice were investigated. The role of glucocorticoids (GC) in the immunomodulation was also examined. Proliferative responses of spleen cells from control mice stimulated with concanavalin A (Con A) were significantly suppressed by adding peritoneal exudate cells from old mice. Flow cytometry analysis revealed that the proportion of MAC-1+ cells with a high density of type II or type III receptor for the Fc portion of IgG (Fc gamma RII/IIIbright cells) was increased markedly in the periotoneal exudate cells from old mice. The prominent suppressor activity for Con A responses of control spleen cells was found in the Fc gamma RII/IIIbright cells, whereas MAC-1+ cells with a low density of Fc gamma RII/III (Fc gamma RII/IIIdull cells) did not suppress the Con A responses. On the other hand, both the basal corticosterone concentrations in serum and the mRNA expression for GC receptor in peritoneal exudate cells increased significantly in old mice. Furthermore, the proportion of Fc gamma RII/IIIbright cells in peritoneal exudate cells from old mice was normalized on administration of the GC antagonist RU 38,486 (mifepristone). These results suggest that the increase in basal corticosterone concentrations in old mice induces the generation of Fc gamma RII/IIIbright suppressor cells, possibly leading to the immune-suppressive state.
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Affiliation(s)
- T Kizaki
- Department of Hygiene, National Defense Medical College, Saitama, Japan
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Veenema HC, Spruijt BM, Gispen WH, van Hooff JA. Aging, dominance history, and social behavior in Java-monkeys (Macaca fascicularis). Neurobiol Aging 1997; 18:509-15. [PMID: 9390777 DOI: 10.1016/s0197-4580(97)00107-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The aim of this study was to investigate the influence of the dominance history of socially housed Java-monkeys on the aging process. In monkeys, social subordinance is generally associated with elevated levels of cortisol, which, in turn, have been suggested to influence cognitive decline. As cognitive skills are necessary for successful social life, we investigated the effect of old age in relation to the dominance history of the animals on their social behavior by comparing old females with their younger daughters. Old age, especially in combination with a history of low rank, led to a withdrawal from social interactions with unfamiliar animals and to a decrease in amounts of aggression received. Still, however, old animals showed an increase in behaviors associated with arousal. A reduced ability to deal with complex social interactions, caused by a decline in information processing abilities, is suggested as an explanation for these results.
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Affiliation(s)
- H C Veenema
- Ethology and Socio-ecology, Department of Comparative Physiology, Utrecht University, The Netherlands
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Barry TP, Riebe JD, Parrish JJ, Malison JA. Effects of 17alpha,20beta-dihydroxy-4-pregnen-3-one on cortisol production by rainbow trout interrenal tissue in vitro. Gen Comp Endocrinol 1997; 107:172-81. [PMID: 9245525 DOI: 10.1006/gcen.1997.6910] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Physiological levels of 17alpha,20beta-dihydroxy-4-pregnen-3-one (17, 20-P) stimulated time- and dose-dependent increases in cortisol production by rainbow trout (Oncorhynchus mykiss) interrenal tissue cultured in vitro. Significant stimulation occurred in response to 100, 300, and 1000 ng/ml of 17,20-P. Lower doses were ineffective. Elevated cortisol levels were observed 1 hr after addition of 300 ng/ml 17,20-P. No additive or synergistic interaction was evident between human adrenocorticotropin fragment 1-24 (ACTH1-24) and 17, 20-P in stimulating cortisol secretion, although 300 ng/ml 17,20-P could further enhance cortisol production above levels already stimulated by 300 ng/ml ACTH. 17alpha, 20alpha-dihydroxy-4-pregnen-3-one also stimulated cortisol secretion, but was only half as effective as 17,20-P. Estradiol-17beta, testosterone, and 11-ketotestosterone had no effect on cortisol secretion. Inhibitors of mRNA and protein synthesis had no effect on 17,20-P-stimulated cortisol production. Radiotracer studies demonstrated that the bioconversion of 17,20-P to cortisol could fully account for the cortisol produced by the interrenal in response to 17,20-P and demonstrated that rainbow trout interrenal cells contain an active 20beta-hydroxysteroid dehydrogenase. These data suggest that 17,20-P may be a regulator of cortisol production during the periovulatory period in salmonid fishes.
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Affiliation(s)
- T P Barry
- Department of Food Science, University of Wisconsin Aquaculture Program, 123 Babcock Hall, Madison, Wisconsin, 53706, USA
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Abstract
Information on the role of glucocorticoids in the aging of vertebrate species is reviewed. There is strong evidence that elevated plasma glucocorticoid levels have a causal role in the rapid deterioration following reproduction in semelparous vertebrate species. If this deterioration is an example of rapid senescence, then it is clear that glucocorticoids can promote aging processes in vertebrate species. However, the evidence that glucocorticoids promote aging in the gradual senescence characteristic of most vertebrate species is not robust. Indeed, there is reason to believe that periods of moderately elevated plasma glucocorticoid levels may retard aging processes in rats, mice, and humans.
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Affiliation(s)
- E J Masoro
- Aging Research and Education Center, University of Texas Health Science Center, San Antonio, USA
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Nelson JF. The Potential Role of Selected Endocrine Systems in Aging Processes. Compr Physiol 1995. [DOI: 10.1002/cphy.cp110115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Leakey JE, Chen S, Manjgaladze M, Turturro A, Duffy PH, Pipkin JL, Hart RW. Role of glucocorticoids and "caloric stress" in modulating the effects of caloric restriction in rodents. Ann N Y Acad Sci 1994; 719:171-94. [PMID: 8010592 DOI: 10.1111/j.1749-6632.1994.tb56828.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- J E Leakey
- Division of Biometry and Risk Assessment, National Center for Toxicological Research, Jefferson, Arkansas 72079
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