The interactive effects of psychosocial stress and diet composition on health in primates

Impact of adolescent high-fat diet and psychosocial stress on neuroendocrine stress responses and binge eating behavior in adult male Lewis rats

Childhood obesity is a multifactorial disease affecting >160 million adolescents worldwide. Adolescent exposure to obesogenic environments, characterized by access to high-fat diets and stress, precipitates maladaptive eating habits in adulthood such as binge eating. Evidence suggests a strong association between Western-like high-saturated fat (WD) food consumption and dysregulated hormone fluctuations. However, few studies have explored the long-term impact of adolescent WD and psychosocial stress on brain and behavior. This longitudinal study aimed to investigate the impact of adolescent exposure to an obesogenic diet on stress resiliency and increased susceptibility for binge-like eating behaviors. Adolescent male Lewis rats were given WD (41% fat; n = 40) or control diet (CD, 16% fat; n = 38) for 4 weeks before undergoing a stress protocol of predator exposure and social instability (CDE, WDE, CDU, WDU; n = 16/group). Subjects were provided intermittent WD access (24 h/week) to evaluate binge-like eating behavior in adulthood. Fecal corticosterone and testosterone were measured at four timepoints throughout adolescence and adulthood. WD rats exhibited increased body weight (p = 0.0217) and elevated testosterone in mid-adolescence (p = 0.0312) and blunted stress-induced corticosterone response in mid-late adolescence (CDE:WDE, p = 0.028). Adolescent hormone levels were negatively correlated with binging and explained the variability between adult rats expressing hyperphagic and hypophagic behaviors. These results demonstrate that exposure to WD in adolescence disrupts hormone fluctuations and stress responsivity, with effects persisting into adulthood. This underscores the importance of addressing obesogenic environments early to mitigate their lasting impact on hormone regulation and stress responsiveness.

Mediterranean vs. Western diet effects on the primate cerebral cortical pre-synaptic proteome: Relationships with the transcriptome and multi-system phenotypes

INTRODUCTION

Diet quality mediates aging-related risks of cognitive decline, neurodegeneration, and Alzheimer's disease (AD) through poorly defined mechanisms.

METHODS

The effects of diet on the presynaptic proteome of the temporal cortex were assessed in 36 female cynomolgus macaques randomized to Mediterranean or Western diets for 31 months. Associations between the presynaptic proteome, determined by synaptometry by time-of-flight (SynTOF) mass spectrometry, adjacent cortex transcriptome, and multi-system phenotypes were assessed using a machine learning approach.

RESULTS

Six presynaptic proteins (DAT, Aβ42, calreticulin, LC3B, K48-Ubiquitin, SLC6A8) were elevated in the presynaptic proteome in Mediterranean diet consumers (p < 0.05). Transcriptomic data and multi-system phenotypes significantly predicted SynTOF markers. Selected SynTOF markers were correlated with changes in white matter volumes, hepatosteatosis, and behavioral and physiological measures of psychosocial stress.

DISCUSSION

These observations demonstrate that diet composition drives cortical presynaptic protein composition, that transcriptional profiles strongly predict the presynaptic proteomic profile, and that presynaptic proteins were closely associated with peripheral metabolism, stress responsivity, neuroanatomy, and socio-emotional behavior.

HIGHLIGHTS

Mediterranean and Western diets differentially altered the cortical presynaptic proteome, which is strongly associated with neurodegeneration and cognitive decline. Presynaptic proteomic markers were predicted by transcriptomic profiles in the adjacent cortex, and by multi-system anatomical, physiologic, and behavioral phenotypes. The data demonstrate that brain phenotypes and brain-body interactions are influenced by common dietary patterns, suggesting that improving diet quality may be an effective means to maintain brain health.

Adherence to the Mediterranean Diet in Spanish University Students: Association with Lifestyle Habits, Mental and Emotional Well-Being

Background: The Mediterranean Diet is recognized as one of the healthiest dietary patterns; however, in recent years, a decline in adherence has been observed in Mediterranean countries. University students represent a particularly vulnerable population, as starting university introduces new influences and responsibilities that directly impact their lifestyle and health. Objective: Analyze adherence to the Mediterranean Diet among university students and its association with other lifestyle habits and mental and physical health indicators. Methods: A cross-sectional study was conducted with a sample of 1268 students (23.65 ± 7.84 years) from a university in northern Spain between November 2020 and March 2021. An online questionnaire was administered to assess Mediterranean Diet adherence along with variables such as perceived stress, self-esteem, life satisfaction, suicidal behavior, emotional and behavioral problems, emotional intelligence, physical activity, sedentary behavior, alcohol consumption, and compulsive internet use. Results: 29.26% of students had high adherence to the Mediterranean Diet. Regression analysis indicated that high adherence was associated with higher levels of emotional intelligence, as well as lower levels of suicidal ideation, emotional problems, and compulsive internet use. Conclusions: The associations found between Mediterranean Diet and other indicators and lifestyle habits highlight the need for interdisciplinary promotion strategies within the university ecosystem.

Concussion and the Autonomic, Immune, and Endocrine Systems: An Introduction to the Field and a Treatment Framework for Persisting Symptoms

A significant proportion of patients who sustain a concussion/mild traumatic brain injury endorse persisting, lingering symptoms. The symptoms associated with concussion are nonspecific, and many other medical conditions present with similar symptoms. Medical conditions that overlap symptomatically with concussion include anxiety, depression, insomnia, chronic pain, chronic fatigue, fibromyalgia, and cervical strain injuries. One of the factors that may account for these similarities is that these conditions all present with disturbances in the optimal functioning of the autonomic nervous system and its intricate interactions with the endocrine system and immune system-the three primary regulatory systems in the body. When clinicians are working with patients presenting with persisting symptoms after concussion, evidence-based treatment options drawn from the literature are limited. We present a framework for the assessment and treatment of persisting symptoms following concussion based on the available evidence (treatment trials), neuroanatomical principles (research into the physiology of concussion), and clinical judgment. We review the research supporting the premise that behavioral interventions designed to stabilize and optimize regulatory systems in the body following injury have the potential to reduce symptoms and improve functioning in patients. Foundational concussion rehabilitation strategies in the areas of sleep stabilization, fatigue management, physical exercise, nutrition, relaxation protocols, and behavioral activation are outlined along with practical strategies for implementing intervention modules with patients.

Impact of adolescent high-fat diet and psychosocial stress on neuroendocrine stress responses and binge eating behavior in adult male Lewis rats

Childhood obesity is a multifactorial disease affecting more than 160 million adolescents worldwide. Adolescent exposure to obesogenic environments, characterized by access to high-fat diets and stress, precipitates maladaptive eating habits in adulthood such as binge eating. Evidence suggests a strong association between Western-like high-saturated-fat (WD) food consumption and dysregulated hormone fluctuations. However, few studies have explored the long-term impact of adolescent WD and psychosocial stress on brain and behavior. This longitudinal study aimed to investigate the impact of adolescent exposure to an obesogenic diet on stress resiliency and increased susceptibility for binge-like eating behaviors. Adolescent male Lewis rats were given WD (41% fat; n=40) or control diet (CD, 16% fat; n=38) for 4 weeks before undergoing a stress paradigm of predator exposure and social instability (CDE, WDE, CDU, WDU; n=16/group). Subjects were provided intermittent WD access (24 h/week) to evaluate binge eating-like behavior in adulthood. Fecal corticosterone and testosterone were measured at four timepoints throughout adolescence and adulthood. WD rats exhibited increased body weight (p = 0.0217) and elevated testosterone in mid-adolescence (p=0.0312) and blunted stress-induced corticosterone response in mid-late adolescence (CDE:WDE, p=0.028). Adolescent hormone levels were negatively correlated with bingeing and explained the variability between adult rats expressing hyperphagic and hypophagic behaviors. These results demonstrate that exposure to WD in adolescence disrupts hormone fluctuations and stress responsivity, with effects persisting into adulthood. This underscores the importance of addressing obesogenic environments early to mitigate their lasting impact on hormone regulation and stress responsiveness.

Animal Models Relevant for Geroscience: Current Trends and Future Perspectives in Biomarkers, and Measures of Biological Aging

For centuries, aging was considered inevitable and immutable. Geroscience provides the conceptual framework to shift this focus toward a new view that regards aging as an active biological process, and the biological age of an individual as a modifiable entity. Significant steps forward have been made toward the identification of biomarkers for and measures of biological age, yet knowledge gaps in geroscience are still numerous. Animal models of aging are the focus of this perspective, which discusses how experimental design can be optimized to inform and refine the development of translationally relevant measures and biomarkers of biological age. We provide recommendations to the field, including: the design of longitudinal studies in which subjects are deeply phenotyped via repeated multilevel behavioral/social/molecular assays; the need to consider sociobehavioral variables relevant for the species studied; and finally, the importance of assessing age of onset, severity of pathologies, and age-at-death. We highlight approaches to integrate biomarkers and measures of functional impairment using machine learning approaches designed to estimate biological age as well as to predict future health declines and mortality. We expect that advances in animal models of aging will be crucial for the future of translational geroscience but also for the next chapter of medicine.

Mediterranean diet protects against a neuroinflammatory cortical transcriptome: Associations with brain volumetrics, peripheral inflammation, social isolation, and anxiety in nonhuman primates (Macaca fascicularis)

Mediterranean diets may be neuroprotective and prevent cognitive decline relative to Western diets; however, the underlying biology is poorly understood. We assessed the effects of Western versus Mediterranean-like diets on RNAseq-generated transcriptional profiles in lateral temporal cortex and their relationships with longitudinal changes in neuroanatomy, circulating monocyte gene expression, and observations of social isolation and anxiety in 38 socially-housed, middle-aged female cynomolgus macaques (Macaca fascicularis). Diet resulted in differential expression of seven transcripts (FDR < 0.05). Cyclin dependent kinase 14 (CDK14), a proinflammatory regulator, was lower in the Mediterranean group. The remaining six transcripts [i.e., "lunatic fringe" (LFNG), mannose receptor C type 2 (MRC2), solute carrier family 3 member 2 (SLCA32), butyrophilin subfamily 2 member A1 (BTN2A1), katanin regulatory subunit B1 (KATNB1), and transmembrane protein 268 (TMEM268)] were higher in cortex of the Mediterranean group and generally associated with anti-inflammatory/neuroprotective pathways. KATNB1 encodes a subcomponent of katanin, important in maintaining microtubule homeostasis. BTN2A1 is involved in immunomodulation of γδ T-cells which have anti-neuroinflammatory and neuroprotective effects. CDK14, LFNG, MRC2, and SLCA32 are associated with inflammatory pathways. The latter four differentially expressed cortex transcripts were associated with peripheral monocyte transcript levels, neuroanatomical changes determined by MRI, and with social isolation and anxiety. These results provide important insights into the potential mechanistic processes linking diet, peripheral and central inflammation, and behavior. Collectively, our results provide evidence that, relative to Western diets, Mediterranean diets confer protection against peripheral and central inflammation which is reflected in preserved brain structure and socioemotional behavior. Ultimately, such protective effects may confer resilience to the development of neuropathology and associated disease.

The fortunes and misfortunes of social life across the life course: A new era of research from field, laboratory and comparative studies

Social gradients in health and aging have been reported in studies across many human populations, and - as the papers included in this special collection highlight - also occur across species. This paper serves as a general introduction to the special collection of Neuroscience and Biobehavioral Reviews entitled "Social dimensions of health and aging: population studies, preclinical research, and comparative research using animal models". Authors of the fourteen reviews are primarily members of a National Institute of Aging-supported High Priority Research Network on "Animal Models for the Social Dimensions of Health and Aging". The collection is introduced by a foreword, commentaries, and opinion pieces by leading experts in related fields. The fourteen reviews are divided into four sections: Section 1: Biodemography and life course studies; Section 2: Social behavior and healthy aging in nonhuman primates; Section 3: Social factors, stress, and hallmarks of aging; Section 4: Neuroscience and social behavior.

Perspective: Promoting Healthy Aging through Nutrition: A Research Centers Collaborative Network Workshop Report

Within 20 y, the number of adults in the United States over the age of 65 y is expected to more than double and the number over age 85 y is expected to more than triple. The risk for most chronic diseases and disabilities increases with age, so this demographic shift carries significant implications for the individual, health care providers, and population health. Strategies that delay or prevent the onset of age-related diseases are becoming increasingly important. Although considerable progress has been made in understanding the contribution of nutrition to healthy aging, it has become increasingly apparent that much remains to be learned, especially because the aging process is highly variable. Most federal nutrition programs and nutrition research studies define all adults over age 65 y as "older" and do not account for physiological and metabolic changes that occur throughout older adulthood that influence nutritional needs. Moreover, the older adult population is becoming more racially and ethnically diverse, so cultural preferences and other social determinants of health need to be considered. The Research Centers Collaborative Network sponsored a 1.5-d multidisciplinary workshop that included sessions on dietary patterns in health and disease, timing and targeting interventions, and health disparities and the social context of diet and food choice. The agenda and presentations can be found at https://www.rccn-aging.org/nutrition-2023-rccn-workshop. Here we summarize the workshop's themes and discussions and highlight research gaps that if filled will considerably advance our understanding of the role of nutrition in healthy aging.

Higher adherence to a Mediterranean-type diet is associated with reduced psychosocial stress levels in baby boomers: a cross-sectional study

BACKGROUND/OBJECTIVES

This study investigated the relationship between adherence to the Mediterranean diet among Korean baby boomers and their levels of psychosocial stress.

SUBJECTS/METHODS

The study included 1,656 adults (889 men and 797 women) born between 1955 and 1963 who participated in the 2005-2006 survey of the community-based Korean Genome and Epidemiology Study (KoGES). The Mediterranean-type diet score (MTDS) was calculated from the semi-quantitative food frequency questionnaire (SQFFQ) data. The psychosocial stress levels were calculated using the psychosocial well-being index-short form (PWI-SF). Logistic regression analyses were performed to analyze the association between the MTDS (tertiles) and the prevalence of high psychosocial stress by gender.

RESULTS

The ranges of the MTDS tertile groups were T1 (20-33 points), T2 (34-37 points), and T3 (38-39 points) for men, T1 (20-33 points), T2 (34-37 points), and T3 (38-48 points) for women. In both men and women, the consumption of whole grains, potatoes, fruits, vegetables, legumes, and fish increased with higher MTDS, while the consumption of red meat and dairy products decreased (P for trend < 0.05). As MTDS score increased the intake of energy, fiber, vitamins, and minerals (P for trend < 0.05). Men in the highest MTDS tertile had a 41% lower odds ratio (OR) of high psychosocial stress compared with those in the lowest tertile (OR, 0.59; 95% confidence interval [CI], 0.38-0.91). Similarly, women in the highest tertile of the MTDS had a 39% lower OR of high psychosocial stress compared with those in the lowest tertile (OR, 0.61; 95% CI, 0.40-0.95).

CONCLUSION

Promoting adherence to the Mediterranean diet among baby boomers may have a positive impact on reducing their levels of psychosocial stress.

A central role for stressor appraisal in the social dimensions of health and aging in nonhuman primates

Being social is by no means the default in the animal kingdom; even most mammals meet only briefly to mate and otherwise lead happy solitary lives. Because conspecifics occupy the same ecological niche, seek the same ecological conditions and resources, they can be each other's strongest competitors when resources are scarce. Yet, sociality, i.e. associating, communicating, coordinating, cooperating, and competing in structured ways, has evolved independently many times across the tree of life. The consequences of competition and conflict are often not shared equally among members of a society, resulting in status-associated health prospects. In response, affiliative strategies have evolved to navigate such structured societies and to partially compensate for certain costs of sociality. The importance of such affiliative strategies may change with age and neurodegenerative disease. Their shared longevity, physiological and anatomical similarity, including in brain areas affected by aging, and particularly the homologies in how social status, affiliation, and cooperation structure their societies, make nonhuman primates the preferred models for the social dimensions of health and aging in humans.