Entire Adult Lifespan Research Articles

Canadian adult reference data for body composition, trabecular bone score and advanced hip analysis using DXA

DXA-derived reference data for visceral adipose tissue (VAT) and advanced hip analysis (AHA) parameters spanning the entire adult lifespan are limited. The purpose of this study was to develop age-, site- and sex-specific reference data for dual X-ray absorptiometry (DXA) -derived body composition, trabecular bone score (TBS) and advanced hip analysis (AHA) parameters across the adult lifespan. Adults (N = 908; female: 561 and male: 347) from Calgary and the surrounding area over the age of 20 years participated in this study. Participants received DXA scans of their hip (total hip [TH] and femoral neck [FN]), lumbar spine [LS], forearm [33 % site] and total body (iDXA, GE Lunar, GE Healthcare). Areal bone mineral density (aBMD, g/cm2) was captured at all sites, and body composition variables, including lean mass, fat mass and percent fat, were analyzed from the total body scan. VAT mass was assessed from total body DXA scans. Advanced hip analysis (AHA) was performed on hip scans and trabecular bone score (TBS) on the LS scans to assess bone quality. Site- and sex-specific centile curves and tables were generated using the Generalized Additive Models for Location, Scale, and Shape (GAMLSS) method. Clinicians and researchers can use these Canadian reference data as a tool to assess body composition, TBS and AHA parameters across the adult lifespan.

Marking Helicoverpa zea (Lepidoptera: Noctuidae) with fluorophores for use in mark-release-recapture research

Abstract Knowledge of insect dispersal and long-distance migratory flight capacity and patterns represent key factors needed for risk assessment of invasive pest species, insecticide resistance management, and more effective pest control. Having operative tools to both mark and track insect pest movement is therefore critical to achieving such goals. Here, we describe a new procedure for marking Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), one of the most economically important crop pests in the United States. Adult H. zea moths were effectively marked using the liquid fluorophore cartax green, a persistent UV-fluorescent pigment, both directly by topical application and indirectly by briefly submerging pupae in the marking solution prior to adult emergence. Regardless of the application method, the cartax mark was retained on the moths throughout their entire adult lifespan. No mortality differences were observed between cartax green-marked and water-marked (control) moths. Additionally, using rotary flight mills, we found no significant differences in several flight parameters, including total number of flights, flight speeds, flight distances, or flight durations between unmarked and cartax-marked moths. Under laboratory conditions, we did observe the lateral transfer of different colored fluorophores between moths, indicating that undesirable marking could potentially occur. Moreover, we found that not all fluorophores were equally retained on H. zea moths, with cartax green remaining intact on moths longer than did a corresponding magenta fluorophore. The results show that cartax green fluorophore could be a practical marker for H. zea and other holometabolous species targeted for large-scale mark-release-recapture research.

Perceived expectations for active aging: the role of motivational and personality factors

Objectives Perceived expectations for active aging (PEAA) reflect subjective exposure to social expectations about staying active and fit in old age, for example, by maintaining health and social engagement. We investigated whether motivational and personality factors were related to PEAA in the domains of physical health, mental health, and social engagement. Method We used a nationally representative sample of German adults (SOEP-IS) covering the entire adult life span (N = 2,007, age range 16–94 years) to test our pre-registered hypotheses. Results Multiple regression analyses indicated that motivation (i.e. life goals and health-related worries) was consistently associated with PEAA in the matching domains and mediated the effects of openness to experience on PEAA. No other personality trait was associated with PEAA. Conclusion Our findings suggest that individuals preferentially notice the expectations for active aging whose content relates to their personal concerns and goals.

Can personality disorder be accurately assessed in older age? A differential item functioning analysis of ICD-11 inventories.

The contested categorical personality disorder (PD) criteria are not well suited to inform PD diagnoses in older adults. Yet, the classification of PDs is undergoing a critical transition phase with a paradigm shift to a dimensional approach for diagnosing PDs. No special attention was given to the expression of PDs in older age when the dimensional ICD-11 model was developed. Given that PDs are highly prevalent in older adults, there is an urgent need to examine if ICD-11 related instruments are able to adequately assess for PDs in older adults. The age-neutrality of ICD-11 measures was examined in a sample of 208 Dutch community-dwelling adults (N=208, M age=54.96, SD=21.65), matched on sex into 104 younger (age range 18-64) and 104 older (age range 65-93) adults. An instrument is considered not to be age-neutral if a collective large level of differential item functioning (DIF) exists in a group of items of an instrument (i.e., 25% or more with DIF). We therefore set out to detect possible DIF in the following ICD-11 self-report measures: the Standardized Assessment of Severity of Personality Disorder (SASPD), the Personality Inventory for ICD-11 (PiCD), and the Borderline Pattern Scale (BPS). DIF analyses using a non-parametric odds ratio approach demonstrated that SASPD, PiCD, and BPS were age-neutral with less than 25% of items showing DIF. Yet, impact of DIF at scale level, examined by way of differential test functioning (DTF), indicated a DTF effect on the SASPD total score. These results of age-neutrality of the PiCD and BPS are promising for measuring ICD-11 traits and the borderline pattern. Yet, the age-neutral measurement of PD severity requires further research. With a rapidly aging population, its accurate assessment across the entire adult life span, including older age, is a prerequisite for an adequate detection of PDs.

Ignorance is not a blessing: Aging exists! The Role of Religion, Spirituality, and Belief in the Comprehension and Acceptance of Aging

Aging is an inevitable part of life. It brings forth a plethora of changes, both physical and emotional, that can pose several challenges for individuals. In this article, we will delve into the issues associated with aging, explore their impact on daily life, and provide insights on how to navigate through them gracefully. We all know that Aging is nothing more than a natural stage of life. "Aging takes place in a cell, an organ, or the total organism with the passage of time. It is a process that goes on over the entire adult life span of any living thing." [1] Still, while speaking of it, it is mainly surrounded by positive narratives and pleasant thoughts - all of which were created not to highlight the quality and value of old age but to give all those who have not yet reached it a sugarcoated image. Things are entirely different for those approaching or already deep into this [final] stage of life. "Old age [is] heavy clothes" is one of the folk Romanian sayings accom-panying this stage – emphasizing the unwieldiness of this stage. The concept of positive Aging is constantly gaining attention in the literature as an approach to health and well-being that incorporates a range of factors in the lives of older adults. But, religion, through theological explanation, has a different approach to aging and approaching death. Let us see what the depths of religious thinking about aging and theological grounds embodied in religious faiths and practices, making specific behaviors conform to these beliefs. The possibility of controlling aging effects is so biased, as if you were trying to build a dam in the middle of the floods. That is why the conclusion of the study is not limited to the management of the effects of aging or to the recognition of the problems it faces and stipulates a method of approaching aging in advance as pre-vention.

Thinking twice: examining gender differences in repetitive negative thinking across the adult lifespan.

A wealth of literature shows that women report greater levels of repetitive negative thinking, particularly rumination, than men in adolescence and adulthood. However, little research has examined how these gender differences develop or change across the entire adult lifespan. The present study addresses these oversights using a nationwide longitudinal probability sample of adults over 12 annual assessment points (N = 64,901; Mage = 42.50, range 18-81; 62.9% women) and a single-item measure of global repetitive negative thinking. Critically, we use multigroup cohort-sequential latent growth modeling to determine whether changes in this construct over time are due to (a) normative aging, (b) generational differences associated with the historical period one was born and raised in, or (c) a combination of these processes. Our results reveal that rumination peaks in young adulthood for both women and men but declines steadily thereafter, reaching its lowest levels at the end of the adult lifespan. That said, some gender and cohort differences emerged, with young women-particularly young cohorts-reporting higher levels of rumination than their male counterparts and older birth cohorts. Our study suggests that gender differences in rumination may be most prevalent among young birth cohorts, though future research is needed to elucidate the mechanisms underlying these processes.

Post-educator relaxation in the U-shaped curve: Evidence from a panel study of Tyneside (ing)

AbstractAge-grading—a cornerstone of sociolinguistic theorizing—is hypothesized to follow a U-shaped pattern. Vernacular forms peak in adolescence, abate in middle age, and increase again in retirement, forming a vernacular tail. A complete understanding of age-grading has been hampered by a lack of empirical evidence across the entire adult trajectory and a relatively narrow understanding of speakers’ motivations to change. This paper presents data from a dynamic panel dataset of Tyneside English speakers, covering successive cohorts over the entire adult lifespan. An analysis of (ing) reveals that the U-shaped curve is occupationally niched; only professional educators demonstrate clear retrenchment followed by a tail. Drawing on educational policy research, we argue this effect is largely driven by institutional (and heavily policed) expectations of UK educational policies. We are the first to demonstrate the occupationally niched nature of the U-shaped curve and provide quantitative evidence of the effect of educational policy on linguistic production.

Longitudinal changes in gray matter correspond to changes in cognition across the lifespan: implications for theories of cognition

The present study examines the association between gray matter volume and cognition. Studies that have examined this issue have focused primarily on older adults, whereas the present study examines the issue across the entire adult lifespan. A total of 463 adults, ages 20–88 at first assessment, were followed longitudinally across three assessments over 8–10years. Significant individual differences in a general cognition measure comprised of measures of speed of processing, working memory, and episodic memory were observed, as well as in measures of cortical and subcortical gray matter. Parallel process latent growth curve modeling showed a reliable relationship between decreases in cortical matter and cognitive decline across the entire adult lifespan, which persisted after controlling for age effects. Implications of these findings in relation to progression toward dementia, risk assessment, cognitive intervention, and environmental factors are discussed, as well as implications for theories of cognitive aging.

Emotional recognition across the adult lifespan: Effects of age, sex, cognitive empathy, alexithymia traits, and amygdala subnuclei volumes.

The ability to recognize others' emotions is vital to everyday life. The goal of this study was to assess which emotions show age-related decline in recognition accuracy of facial emotional expressions across the entire adult lifespan and how this process is related to cognitive empathy (Theory of Mind [ToM]), alexithymia traits, and amygdala subnuclei volumes in a large cohort of healthy individuals. We recruited 140 healthy participants 18-85 years old. Facial affect processing was assessed with the Penn Emotion Recognition task (ER40) that contains images of the five basic emotions: Neutral, Happy, Sad, Angry, and Fearful. Structural magnetic resonance imaging (MRI) datasets were acquired on a 4.7T MRI system. Structural equation modeling was used to test the relationship between studied variables. We found that while both sexes demonstrated age-related reduction in recognition of happy emotions and preserved recognition of sadness, male participants showed age-related reduction in recognition of fear, while in female participants, age-related decline was linked to recognition of neutral and angry facial expressions. In both sexes, accurate recognition of sadness negatively correlated with alexithymia traits. On the other hand, better ToM capabilities in male participants were associated with improvement in recognition of positive and neutral emotions. Finally, none of the observed age-related reductions in emotional recognition were related to amygdala and its subnuclei volumes. In contrast, both global volume of amygdala and its cortical and centromedial subnuclei had significant direct effects on recognition of sad images.

Differential effects of age and sex on medial temporal lobe networks revealed by longitudinal analyses across the adult lifespan

AbstractBackgroundThe medial temporal lobe (MTL) is extensively connected to the rest of the brain through two specific networks which are particularly affected in Alzheimer’s disease (AD): the anterior‐temporal (AT) and posterior‐medial (PM) systems. As the specific and respective effects of age and sex on the functional integrity of these networks are still largely unknown, we sought to fill this gap using longitudinal data spanning the entire adult life.MethodLongitudinal data from 215 cognitively unimpaired adults (aged 19‐85, including 113 females, followed‐up up to 47 months, 419 scans) were analysed. Seed‐based analyses were applied to resting‐state functional magnetic resonance imaging to generate connectivity maps (seeds: the perirhinal cortex for AT and the parahippocampal cortex for PM). The AT and PM networks were defined by comparing baseline maps from adults younger than 40 using a paired permutation t‐test with threshold‐free cluster enhancement (TFCE) and familywise error (FWE) correction (p<.05) (Figure 1). These masks were then used to extract the mean functional connectivity (FC) for each participant. The interaction effects between network, age and sex were investigated using linear mixed models.ResultThere was a significant interaction between age and networks (p<.001), with a decrease of FC with age in PM and an increase in AT (Figure 2). Sex differences were also observed within these two systems (p<.001), with males exhibiting higher FC than females in AT but lower FC in PM (Figure 3). Age‐related trajectories were not modulated by sex differences (p>.05) and were best described by a linear relationship according to model comparison testing different polynomials.ConclusionBy encompassing the entire adult lifespan and assessing longitudinal changes, our study provides strong support that the two MTL networks display differential alterations in the context of aging, as well as sex differences. Since MTL connectivity has been described as particularly affected in the early stages of AD, and age and sex are risk factors, these findings may be helpful to enhance the clinical utility of such biomarkers for the early detection of AD‐related changes.

Differential effects of age and sex on medial temporal lobe networks revealed by longitudinal analyses across the adult lifespan

AbstractBackgroundThe medial temporal lobe (MTL) is extensively connected to the rest of the brain through two specific networks which are particularly affected in Alzheimer’s disease (AD): the anterior‐temporal (AT) and posterior‐medial (PM) systems. As the specific and respective effects of age and sex on the functional integrity of these networks are still largely unknown, we sought to fill this gap using longitudinal data spanning the entire adult life.MethodLongitudinal data from 215 cognitively unimpaired adults (aged 19‐85, including 113 females, followed‐up up to 47 months, 419 scans) were analysed. Seed‐based analyses were applied to resting‐state functional magnetic resonance imaging to generate connectivity maps (seeds: the perirhinal cortex for AT and the parahippocampal cortex for PM). The AT and PM networks were defined by comparing baseline maps from adults younger than 40 using a paired permutation t‐test with threshold‐free cluster enhancement (TFCE) and familywise error (FWE) correction (p<.05) (Figure 1). These masks were then used to extract the mean functional connectivity (FC) for each participant. The interaction effects between network, age and sex were investigated using linear mixed models.ResultThere was a significant interaction between age and networks (p<.001), with a decrease of FC with age in PM and an increase in AT (Figure 2). Sex differences were also observed within these two systems (p<.001), with males exhibiting higher FC than females in AT but lower FC in PM (Figure 3). Age‐related trajectories were not modulated by sex differences (p>.05) and were best described by a linear relationship according to model comparison testing different polynomials.ConclusionBy encompassing the entire adult lifespan and assessing longitudinal changes, our study provides strong support that the two MTL networks display differential alterations in the context of aging, as well as sex differences. Since MTL connectivity has been described as particularly affected in the early stages of AD, and age and sex are risk factors, these findings may be helpful to enhance the clinical utility of such biomarkers for the early detection of AD‐related changes.

A unified model for reconstruction and [formula omitted] mapping of accelerated 7T data using the quantitative recurrent inference machine

Quantitative MRI (qMRI) acquired at the ultra-high field of 7 Tesla has been used in visualizing and analyzing subcortical structures. qMRI relies on the acquisition of multiple images with different scan settings, leading to extended scanning times. Data redundancy and prior information from the relaxometry model can be exploited by deep learning to accelerate the imaging process. We propose the quantitative Recurrent Inference Machine (qRIM), with a unified forward model for joint reconstruction and R2*-mapping from sparse data, embedded in a Recurrent Inference Machine (RIM), an iterative inverse problem-solving network. To study the dependency of the proposed extension of the unified forward model to network architecture, we implemented and compared a quantitative End-to-End Variational Network (qE2EVN). Experiments were performed with high-resolution multi-echo gradient echo data of the brain at 7T of a cohort study covering the entire adult life span. The error in reconstructed R2* from undersampled data relative to reference data significantly decreased for the unified model compared to sequential image reconstruction and parameter fitting using the RIM. With increasing acceleration factor, an increasing reduction in the reconstruction error was observed, pointing to a larger benefit for sparser data. Qualitatively, this was following an observed reduction of image blurriness in R2*-maps. In contrast, when using the U-Net as network architecture, a negative bias in R2* in selected regions of interest was observed. Compressed Sensing rendered accurate, but less precise estimates of R2*. The qE2EVN showed slightly inferior reconstruction quality compared to the qRIM but better quality than the U-Net and Compressed Sensing. Subcortical maturation over age measured by a linearly increasing interquartile range of R2* in the striatum was preserved up to an acceleration factor of 9. With the integrated prior of the unified forward model, the proposed qRIM can exploit the redundancy among repeated measurements and shared information between tasks, facilitating relaxometry in accelerated MRI.

Embryonic Origins of the Hematopoietic System: Hierarchies and Heterogeneity.

The hierarchical framework of the adult blood system as we know it from current medical and hematology textbooks, displays a linear branching network of dividing and differentiated cells essential for the growth and maintenance of the healthy organism. This view of the hierarchy has evolved over the last 75 years. An amazing increase in cellular complexity has been realized; however, innovative single-cell technologies continue to uncover essential cell types and functions in animal models and the human blood system. The most potent cell of the hematopoietic hierarchy is the hematopoietic stem cell. Stem cells for adult tissues are the long-lived self-renewing cellular component, which ensure that differentiated tissue-specific cells are maintained and replaced through the entire adult lifespan. Although much blood research is focused on hematopoietic tissue homeostasis, replacement and regeneration during adult life, embryological studies have widened and enriched our understanding of additional developmental hierarchies and interacting cells of this life-sustaining tissue. Here, we review the current state of knowledge of the hierarchical organization and the vast heterogeneity of the hematopoietic system from embryonic to adult stages.

Nutrient effects on working memory across the adult lifespan

ABSTRACT Objective To identify the nutrients that influence the performance of working memory, which is greatly affected as age progresses. Method A total of 1646 healthy adults between 21 and 80 years old participated in the study. The daily consumption of 64 nutrients was examined using a food frequency questionnaire that assessed food intake during the previous year. Working memory was measured in the verbal and spatial domains using a computerized task. We examined which nutrients influence working memory across the entire adult lifespan and whether the influence of any of these nutrients on working memory is moderated by individuals’ ages. Results Working memory, across the entire adult lifespan, benefits from the intake of cholesterol, alcohol, gamma- and delta-tocopherol, vitamin B6, and palmitoleic, oleic, alpha linoleic and linoleic acids. Moderator analyses revealed that fats, energy, lactose and sodium negatively influenced working memory in middle-aged and older adults, whereas vitamin D and vitamin C had positive effects on memory beyond 70 years of age. Conclusion Nutrients have the ability to positively or negatively affect working memory, which varies as a function of age.

Longitudinal cascades of Alzheimer disease biomarkers across the entire adult lifespan among cognitively normal adults

AbstractBackgroundThe temporal cascade of Alzheimer disease (AD) biomarkers among cognitively normal individuals, including cerebral spinal fluid (CSF) Aβ42, Aβ40, total tau (Tau) and phosphorylated tau (pTau), standardized uptake value ratio (SUVR) from the molecular imaging of cerebral fibrillar β‐amyloid with positron emission tomography (PET) using the [11C] benzothiazole tracer, Pittsburgh Compound‐B (PiB), magnetic resonance imaging (MRI)‐based hippocampal volume and cortical thickness, and cognition has been hypothesized, but not yet fully tested with longitudinal data.MethodLeveraging a large harmonized database of 2703 cognitively normal individuals 18 to 103 years of age from 8 longitudinal studies with a median follow up of 5∼6 years, we estimated the longitudinal trajectories of all major AD biomarkers as functions of baseline age, located the age window at which the longitudinal change accelerated by comparing it across adjacent age bins, and examined possible modifying effects of apolipoprotein E (APOE) genotypes.ResultParticipants 18 to 45 years of age at baseline exhibited ‘learning effects’ on both cognition and all but the MRI‐based biomarkers. The earliest acceleration of longitudinal change occurred for CSF Aβ42 and Aβ42/Aβ40 ratio at the baseline age of 45 to 50 years, followed by hippocampal volume at the baseline age of 55 to 60 years, further by CSF Tau, PET PiB mean cortical SUVR, cortical thickness, and cognition at the baseline age of 65 to 70 years. The accelerated longitudinal changes remained in the covariate‐adjusted analyses. APOE ε4 modified the observed ‘learning effects’ from 18 to 45 years. Further, there was preliminary evidence that APOE ε4 carriers may have experienced the first significant acceleration of the longitudinal change in almost all major AD markers within the baseline age window of 45 to 55 years, whereas among APOE ε4 non‐carriers, only PiB PET SUVRs and cortical thickness and the cognitive composite showed the earliest longitudinal acceleration of change at the same baseline age interval.ConclusionOur results characterize the temporal cascades of longitudinal changes for all major AD biomarkers across entire adult lifespan, and address the modifying effect of APOE ε4. These findings may better inform the design of prevention trials on AD.

“Put Away Childish Things”: Psychological entitlement has weaker negative associations with wellbeing for emerging adults

Across the lifespan, narcissism is highest amongst emerging adults (aged 18–25), but narcissism may also be more adaptive for emerging adults. We replicate and extend upon previous research by examining the relative adaptiveness of psychological entitlement (a facet of narcissism) across the entire adult lifespan. Using data from a national panel study in New Zealand (N = 47,487), we investigate whether negative associations between entitlement and life satisfaction, self-esteem, and perceived social support are weaker for both emerging adults and for older adults (aged 65+). Results supported this theory for emerging adults, but only weak evidence was found for a similar effect among older adults. These findings support the idea that narcissism may serve different developmental purposes across the lifespan.

Influence of Dietary Nutrient Intake on Episodic Memory Across the Adult Life Span.

The aim of the study was to identify nutrients that have the ability to impact brain functioning and, as a consequence, influence episodic memory. In particular, we examined recollection, the ability to recall details of previous experiences, which is the episodic memory process most affected as age advances. A sample of 1,550 healthy participants between 21 and 80 years old participated in the study. Nutritional intake was examined through a food frequency questionnaire and software developed to determine the daily consumption of 64 nutrients based on food intake during the last year. Recollection was measured through a computerized source memory paradigm. First, we identified which nutrients influence recollection across the entire adult life span. Then, moderator analyses were conducted by dividing the sample into young (21–40 years old), middle-aged (41–60 years old) and older (61–80 years old) adults to establish in which life stage nutrients influence episodic memory. Across the adult life span, recollection accuracy was shown to benefit from the intake of sodium, heme, vitamin E, niacin, vitamin B6, cholesterol, alcohol, fat, protein, and palmitic, stearic, palmitoleic, oleic, gadoleic, alpha-linoleic and linoleic acid. The effects of energy, maltose, lactose, calcium and several saturated fatty acids on recollection were modulated by age; in older adults, the consumption of these nutrients negatively influenced episodic memory performance, and in middle-aged adults, only lactose had negative effects. Several brain mechanisms that support episodic memory were influenced by specific nutrients, demonstrating the ability of food to enhance or deteriorate episodic memory.

The Development of Life Goals Across the Adult Life Span.

Life goals are important organizing units for individual agency in development. On a societal level, they align with age-normative developmental tasks; on the individual level, they guide people's attempts at shaping their own development. This study investigates the development of life goals across the adult life span with a focus on differences regarding gender, parental status, education, and region. Using longitudinal data from the German Socio-Economic Panel study (N = 52,052, age range: 18-84 years), we estimated the developmental trajectories of importance ratings for 9 life goals across the adult life span using multiple-group latent growth curve modeling. Having a happy relationship or marriage, having children, and being there for others are the life goals rated as most important across almost the entire adult life span. Having a happy relationship or marriage differed strongly by gender. Up to middle adulthood it was more important for women, but more important for men in late adulthood. Parental status amplified gender differences in the work and family domain. Low education was associated with a higher perceived importance of being there for others. The largest regional differences (East vs. West) were found for home ownership. Although the importance of some life goal trajectories reflects typical age-grading in developmental tasks, other life goals (e.g., having children) remain important even after goal attainment or after developmental deadlines have passed.

Is adolescence a time of heightened risk taking? An overview of types of risk-taking behaviors across age groups

Adolescence often is thought to be the age period of heightened risk taking (e.g., substance use, reckless driving, sexual risks, delinquency) by both researchers and the general public. In the present article we challenge this assumption by examining the prevalence of a wide variety of real-world risk-taking behaviors across different age groups. Focusing on North American data, we first explore types of risk-taking behaviors across different age groups, both within and across different domains of risk taking. Second, we consider historical trends in risk taking, given that prevalence and types of risk-taking behaviors can change over time. Overall, our review highlights that emerging adulthood (i.e., 19–29 years of age) is the age period when risk taking is most prevalent across multiple domains. Risk taking in many domains, however, is common across the entire adult lifespan, sometimes with the appearance of minimal differences among emerging adults and adults. Moreover, while the majority of risk-taking behaviors have declined over time, this pattern is not consistent for all behaviors and all age groups. Thus, our understanding of whether adolescence is a heightened period of risk taking requires answering the questions: “For what type of risk taking” and “How does that type of risk-taking behavior change or not change across age and historical time periods?”

Hypoxia Tolerance Declines with Age in the Absence of Methionine Sulfoxide Reductase (MSR) in Drosophila melanogaster.

Unlike the mammalian brain, Drosophila melanogaster can tolerate several hours of hypoxia without any tissue injury by entering a protective coma known as spreading depression. However, when oxygen is reintroduced, there is an increased production of reactive oxygen species (ROS) that causes oxidative damage. Methionine sulfoxide reductase (MSR) acts to restore functionality to oxidized methionine residues. In the present study, we have characterized in vivo effects of MSR deficiency on hypoxia tolerance throughout the lifespan of Drosophila. Flies subjected to sudden hypoxia that lacked MSR activity exhibited a longer recovery time and a reduced ability to survive hypoxic/re-oxygenation stress as they approached senescence. However, when hypoxia was induced slowly, MSR deficient flies recovered significantly quicker throughout their entire adult lifespan. In addition, the wildtype and MSR deficient flies had nearly 100% survival rates throughout their lifespan. Neuroprotective signaling mediated by decreased apoptotic pathway activation, as well as gene reprogramming and metabolic downregulation are possible reasons for why MSR deficient flies have faster recovery time and a higher survival rate upon slow induction of spreading depression. Our data are the first to suggest important roles of MSR and longevity pathways in hypoxia tolerance exhibited by Drosophila.