The relationship between social status and atherosclerosis in male and female monkeys as revealed by meta-analysis

Acquisition of cocaine reinforcement using fixed-ratio and concurrent choice schedules in socially housed female and male monkeys

RATIONALE

Previous studies in socially housed monkeys examining acquisition of cocaine self-administration under fixed-ratio (FR) schedules of reinforcement found that subordinate males and dominant females were more vulnerable than their counterparts.

OBJECTIVES

The present studies extended these findings in two ways: (1) to replicate the earlier study, in which female monkeys were studied after a relatively short period of social housing (~ 3 months) using cocaine-naïve female monkeys (n = 9; 4 dominant and 5 subordinate) living in well-established social groups (~ 18 months); and (2) in male monkeys (n = 3/social rank), we studied cocaine acquisition under a concurrent schedule, with an alternative, non-drug reinforcer available.

RESULTS

In contrast to earlier findings, subordinate female monkeys acquired cocaine reinforcement (i.e., > saline reinforcement) at significantly lower cocaine doses compared with dominant monkeys. In the socially housed males, no dominant monkey acquired a cocaine preference (i.e., > 80% cocaine choice) over food, while two of three subordinate monkeys acquired cocaine reinforcement. In monkeys that did not acquire, the conditions were changed to an FR schedule with only cocaine available and after acquisition, returned to the concurrent schedule. In all monkeys, high doses of cocaine were chosen over food reinforcement.

CONCLUSIONS

The behavioral data in females suggests that duration of social enrichment and stress can differentially impact vulnerability to cocaine reinforcement. The findings in socially housed male monkeys, using concurrent food vs. cocaine choice schedules of reinforcement, confirmed earlier social-rank differences using an FR schedule and showed that vulnerability could be modified by exposure to cocaine.

Association between soft drink consumption and carotid atherosclerosis in a large-scale adult population: The TCLSIH cohort study

BACKGROUND AND AIMS

Carotid atherosclerosis indicates an increased risk for cardiac-cerebral vascular disease. Given the pattern of consumption in China, sugar-sweetened beverage is the main type of soft drink consumed. As soft drinks contain a high amount of fructose, they may be a risk factor of carotid atherosclerosis. A prospective cohort study was conducted to investigate the association between soft drink consumption and the incidence of carotid atherosclerosis in a Chinese adult population.

METHODS AND RESULTS

A total of 3828 participants (men: 2007 and women: 1821) were included. Carotid atherosclerosis was measured by using ultrasonography and was defined by increased carotid intima-media thickness and/or carotid plaques. Soft drink consumption was assessed using a validated food frequency questionnaire. Cox proportional hazards regression analysis was used to assess the association of soft drink consumption categories with the incidence of carotid atherosclerosis. During a mean follow-up of 3.20 years, 1009 individuals of the 3828 eligible participants developed carotid atherosclerosis. After adjusting for potential confounding factors, we compared the higher levels to the lowest level of soft drink consumption in women, and we estimated the multivariable hazard ratios and 95% confidence intervals of incident carotid atherosclerosis to be 1.09 (0.80, 1.50), and 1.56 (1.14, 2.13) (P for trend <0.05). However, there was no significant association between soft drink consumption and the incidence of carotid atherosclerosis in men or total population.

CONCLUSION

The result indicated that soft drink consumption was associated with a higher incidence of carotid atherosclerosis in women.

TRIAL REGISTERED

UMIN Clinical Trials Registry.

TRIAL REGISTRATION NUMBER

UMIN000027174. TRIAL REGISTRATION WEBSITE: https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000031137.

Differential effects of western versus mediterranean diets and psychosocial stress on ovarian function in female monkeys (Macaca fascicularis)

Ovarian dysfunction increases risk for chronic diseases of aging including cardiovascular disease, depression, cognitive impairment, as well as bone and muscle loss which promote frailty. Psychosocial stress can disrupt ovarian function, and recent observations suggest that consumption of a Western Diet may also. Determination of causal relationships among diet, psychosocial stress, and ovarian physiology is difficult in humans. Long-tailed (a.k.a. cynomolgus) macaques (Macaca fascicularis) are an excellent translational model for the study of diet and psychosocial effects on ovarian physiology and aging-related processes. They have 28-day menstrual cycles with hormonal fluctuations like those of women, and similar physiologic responses to alterations and/or cessation of cyclicity. We examined ovarian function in 38 middle-aged socially housed females fed either a Western or Mediterranean diet for 31 months (≈ a 9-year period for humans). During the last year, we examined cycle length and peak progesterone per cycle using blood sampling (3/week) and vaginal swabbing for menses (6/week). Repeated measures analysis revealed a circannual pattern consistent with increased menstrual cycle disturbance during the late Summer and early Fall (F(11,348)= 4.05 p < 0.001). In addition, both Western diet (F(1,34)= 3.99; p = 0.05) and the stress of low social status (F(1,34)= 3.99; p = 0.04) reduced mean progesterone levels. Thus, on average, subordinates in the Western group had the lowest average progesterone levels (10.02 ng/pl). Compared to Western diets, Mediterranean diets exhibited protective effects via menstrual cycle regularity. For dominant monkeys, consuming Mediterranean diets resulted in significantly greater likelihood of having regular menstrual cycles. Mediterranean diets also protected individuals from shorter than normal menstrual cycles. The relationships between diet and menstrual regularity were partially mediated by both adrenal reactivity and social isolation. This study demonstrates the additive negative effects of poor diet and psychosocial stress on ovarian physiology in mid-life and lays the groundwork for future investigations to uncover their impact on metabolic signatures of accelerated aging. The results also suggest that - compared to Western-style diets - a Mediterranean diet may exert a protective influence against ovarian dysfunction and its pathologic sequelae.

Delay discounting as a behavioral phenotype associated with social rank in female and male cynomolgus monkeys: Correlation with kappa opioid receptor availability

Cocaine use disorder (CUD) is a significant problem worldwide, with no FDA-approved treatments. Epidemiological data indicate that only about 17 % of people that use cocaine will meet DSM criteria for CUD. Thus, the identification of biomarkers predictive of eventual cocaine use may be of great value. Two potentially useful predictors of CUD are social hierarchies in nonhuman primates and delay discounting. Both social rank and preference for a smaller, immediate reinforcer relative to a larger, delayed reinforcer have been predictive of CUD. Therefore, we wanted to determine if there was also a relationship between these two predictors of CUD. In the present study, monkeys cocaine-naive responded under a concurrent schedule of 1- vs. 3-food pellets and delivery of the 3-pellet option was delayed. The primary dependent variable was the indifference point (IP), which is the delay that results in 50 % choice for both options. In the initial determination of IP, there were no differences based on sex or social rank of the monkeys. When the delays were redetermined after ~25 baseline sessions (range 5-128 sessions), dominant females and subordinate males showed the largest increases in IP scores from the first determination to the second. Because 13 of these monkeys had prior PET scans of the kappa opioid receptor (KOR), we examined the relationship between KOR availability and IP values and found that the change in IP scores from the first to the second determination significantly negatively predicted average KOR availability in most brain regions. Future studies will examine acquisition to cocaine self-administration in these same monkeys, to determine if IP values are predictive of vulnerability to cocaine reinforcement.

Behavioural and physiological plasticity in social hierarchies

Individuals occupying dominant and subordinate positions in social hierarchies exhibit divergent behaviours, physiology and neural functioning. Dominant animals express higher levels of dominance behaviours such as aggression, territorial defence and mate-guarding. Dominants also signal their status via auditory, visual or chemical cues. Moreover, dominant animals typically increase reproductive behaviours and show enhanced spatial and social cognition as well as elevated arousal. These biobehavioural changes increase energetic demands that are met via shifting both energy intake and metabolism and are supported by coordinated changes in physiological systems including the hypothalamic-pituitary-adrenal and hypothalamic-pituitary-gonadal axes as well as altered gene expression and sensitivity of neural circuits that regulate these behaviours. Conversely, subordinate animals inhibit dominance and often reproductive behaviours and exhibit physiological changes adapted to socially stressful contexts. Phenotypic changes in both dominant and subordinate individuals may be beneficial in the short-term but lead to long-term challenges to health. Further, rapid changes in social ranks occur as dominant animals socially ascend or descend and are associated with dynamic modulations in the brain and periphery. In this paper, we provide a broad overview of how behavioural and phenotypic changes associated with social dominance and subordination are expressed in neural and physiological plasticity. This article is part of the theme issue 'The centennial of the pecking order: current state and future prospects for the study of dominance hierarchies'.

Agonism and grooming behaviour explain social status effects on physiology and gene regulation in rhesus macaques

Variation in social status predicts molecular, physiological and life-history outcomes across a broad range of species, including our own. Experimental studies indicate that some of these relationships persist even when the physical environment is held constant. Here, we draw on datasets from one such study-experimental manipulation of dominance rank in captive female rhesus macaques-to investigate how social status shapes the lived experience of these animals to alter gene regulation, glucocorticoid physiology and mitochondrial DNA phenotypes. We focus specifically on dominance rank-associated dimensions of the social environment, including both competitive and affiliative interactions. Our results show that simple summaries of rank-associated behavioural interactions are often better predictors of molecular and physiological outcomes than dominance rank itself. However, while measures of immune function are best explained by agonism rates, glucocorticoid-related phenotypes tend to be more closely linked to affiliative behaviour. We conclude that dominance rank serves as a useful summary for investigating social environmental effects on downstream outcomes. Nevertheless, the behavioural interactions that define an individual's daily experiences reveal the proximate drivers of social status-related differences and are especially relevant for understanding why individuals who share the same social status sometimes appear physiologically distinct. This article is part of the theme issue 'The centennial of the pecking order: current state and future prospects for the study of dominance hierarchies'.

Investigation of Relationship between Occupational Stress and Cardiovascular Risk Factors among Nurses

Background:

One of the major causes of various work-related health problems among nurses is occupational stress. Hence, the main purpose of the present research was to find association between occupational stress of nurses and risk factors of cardiovascular disease.

Methods:

In this cross-sectional study, the Osipow job stress questionnaire was employed to assess the occupational stress among the 250 nurses in Emam Khomeini hospital of Tehran in 2018. Based on stress score for participants, subjects divided into two groups: Scoring of group one was 60–179 (mild and average stress) and group two between 180 and 300 (average to acute and acute stress). Systolic and diastolic blood pressures were recorded for subjects after 10hrs fasting. Then the blood samples were collected to measure cholesterol, triglyceride and glucose levels. For determining the association between education level, job experience and study groups, the Chi-square test and for comparing job stress between two groups of study the Mann–Whitney U test was used.

Results:

Subjects with job stress in group one was 70(28%) and group two was 180(72%). The association between level of education and two study groups was not significant (P=0.129) while between job experience and two study groups was significant (P=0.004). Mean of Blood glucose levels for group I (98.0± 37.5), was higher than group II (82.5±12.0) and statistically significant (P=0.001). No significant difference was found between two groups of study for other parameters.

Conclusion:

High level of work-related stress among subjects affected the values related to blood glucose level, but no significant relationship was found between other risk factors of cardiovascular diseases and occupational stress among nurses.

Short-term effect of stock volatility and cardiovascular mortality: a systematic review and meta-analysis

Background

Cardiovascular disease (CVD) and stroke are leading causes of death. It has several risk factors, including stress and pressure. Stock volatility can cause acute stress for stockholders so that it can cause CVD events. Recently, the spread of new coronaviruses worldwide has affected economic development greatly, leading to more severe stock market fluctuations, so we systematically quantify the short-term effect of stock volatility and CVD events.

Methods

Time-series analysis on the effect of stock volatility and cardiovascular events were concluded. We conducted a systematic literature search for studies published in PubMed, Embase, and Cochrane Data up to the date February 9, 2020. We assessed publication bias using Egger’s test. Overall analysis and sensitivity analysis were conducted separately.

Results

Four studies were finally included. Every 100-point increase in the stock market will bring about 1.01% increases in cardiovascular mortality [95% confidence intervals (CI), −0.18% to 2.21%]. The meta-analysis showed no statistical significance for cardiovascular mortality. Every 100-point increase in the stock market brought 1.01% increases in the cardiovascular mortality [95% CI, −0.18% to 2.21%]. In terms of stroke events, the estimated effect was 2.999% (95% CI, 0.325% to 5.673%). Different lag patterns also have effects on cardiovascular mortality. Every 100-point increase brought about 4.026% (95% CI, 1.516% to 6.536%) and 4.424% (95% CI, 1.145% to 7.703%) for lag 01 and 04 separately.

Conclusions

Though our study has a number of limitations due to the limited studies included, it suggested that stock volatility had a lagging effect on CVD mortality, which may last for several days. Also, it might increase the incidence of stroke.

Psychological stress, cardiac symptoms, and cardiovascular risk in women with suspected ischaemia but no obstructive coronary disease

This paper evaluated cross-sectional relationships between psychological stress and coronary artery disease (CAD) risk among women with suspected ischaemia and no obstructive coronary artery disease (INOCA). Between 1996 and 2000, 551 women with INOCA were enrolled in the Women's Ischemia Syndrome Evaluation (WISE) cohort from four U.S. institutions. Between 2009 and 2012, 376 women with INOCA were recruited from two U.S. institutions for an independent cohort study titled WISE-Coronary Vascular Dysfunction (WISE-CVD). Participants underwent coronary angiography and testing for CAD symptoms and risk factors at baseline. Psychological stress was assessed in the form of home/work stress in WISE and home/work stress and financial stress in WISE-CVD. Results showed that home/work stress predicted greater depression, functional impairment, CAD symptoms, and lower self-rated health in WISE but was inconsistent as a predictor in WISE-CVD. In contrast, >60% of WISE-CVD women reported moderate or severe financial stress. Financial stress levels predicted more CAD risk factors and cardiac symptoms, poorer self-rated health, and greater depression and functional impairment. Among women with INOCA, psychological stress was associated with CAD symptoms and CAD risk factors. The prevalence and predictive value of psychological stress in this population supports the inclusion of stress measures in future CAD research.

The Pathway From Social Status to Physical Health: Taking a Closer Look at Stress as a Mediator

Stress is often invoked as a potential contributor to disparities in physical health as a function of social status. Although there is good reason to believe that stress exposure and stress responses may be an important pathway linking lower social status to poor health, direct evidence is lacking. We summarize the evidence for this pathway and limitations of that evidence, focusing particularly on how stress is conceptualized and measured. We argue that in addition to more direct tests of mediation, the measurement of the mediator—stress—could also be improved. We also propose that measuring theory-specific stress exposures may be more fruitful than assessing general stress exposures (e.g., life events, global perceived stress) by increasing theoretical clarity and predictive utility of stress in this context.

Current understanding of hypothalamic amenorrhoea

Hypothalamic amenorrhoea (HA) accounts for approximately 30% of cases of secondary amenorrhoea in women of reproductive age. It is caused by deficient secretion of hypothalamic gonadotrophin-releasing hormone, which in turn leads to failure of pituitary gonadotrophin and gonadal steroid release. Functional HA (FHA) is defined as HA occurring in the absence of a structural lesion and is predominantly caused by significant weight loss, intense exercise or stress. Treatment of FHA is crucial in avoiding the long-term health consequences on fertility and bone health, in addition to reducing psychological morbidity. This article summarises our understanding of the mechanisms underlying FHA, the evidence base for its clinical management and emerging therapies.

Social history and exposure to pathogen signals modulate social status effects on gene regulation in rhesus macaques

Social experience is an important predictor of disease susceptibility and survival in humans and other social mammals. Chronic social stress is thought to generate a proinflammatory state characterized by elevated antibacterial defenses and reduced investment in antiviral defense. Here we manipulated long-term social status in female rhesus macaques to show that social subordination alters the gene expression response to ex vivo bacterial and viral challenge. As predicted by current models, bacterial lipopolysaccharide polarizes the immune response such that low status corresponds to higher expression of genes in NF-κB-dependent proinflammatory pathways and lower expression of genes involved in the antiviral response and type I IFN signaling. Counter to predictions, however, low status drives more exaggerated expression of both NF-κB- and IFN-associated genes after cells are exposed to the viral mimic Gardiquimod. Status-driven gene expression patterns are linked not only to social status at the time of sampling, but also to social history (i.e., past social status), especially in unstimulated cells. However, for a subset of genes, we observed interaction effects in which females who fell in rank were more strongly affected by current social status than those who climbed the social hierarchy. Taken together, our results indicate that the effects of social status on immune cell gene expression depend on pathogen exposure, pathogen type, and social history-in support of social experience-mediated biological embedding in adulthood, even in the conventionally memory-less innate immune system.

Both diet and Helicobacter pylori infection contribute to atherosclerosis in pre- and postmenopausal cynomolgus monkeys

A number of viruses and bacterial species have been implicated as contributors to atherosclerosis, potentially providing novel pathways for prevention. Epidemiological studies examining the association between Helicobacter pylori and cardiovascular disease have yielded variable results and no studies have been conducted in nonhuman primates. In this investigation, we examined the relationship between H. pylori infection and atherosclerosis development in socially housed, pre- and postmenopausal cynomolgus macaques consuming human-like diets. Ninety-four premenopausal cynomolgus monkeys (Macaca fascicularis) were fed for 36 months an atherogenic diet deriving its protein from either casein lactalbumin(CL) or high isoflavone soy (SOY). Animals were then ovariectomized and fed either the same or the alternate diet for an additional 36 months. Iliac artery biopsies were obtained at the time of ovariectomy and iliac and coronary artery sections were examined at the end of the study. Evidence of H. pylori infection was found in 64% of the monkeys and 46% of animals had live H. pylori within coronary atheromas as determined by mRNA-specific in situ hybridization. There was a significant linear relationship between the densities of gastric and atheroma organisms. Helicobactor pylori infection correlated with increased intimal plaque area and thickness at both the premenopausal and postmenopausal time points and regardless of diet (p< 0.01), although animals consuming the SOY diet throughout had the least amount of atherosclerosis. Additionally, plasma lipid profiles, intimal collagen accumulation, ICAM-1, and plaque macrophage densities were adversely affected by H. pylori infection among animals consuming the CL diet, while the SOY diet had the opposite effect. Plaque measurements were more highly associated with the densities of cagA-positive H. pylori within coronary atheromas than with the densities of gastric organisms, whereas plasma lipid changes were associated with H. pylori infection, but not cagA status. This study provides strong evidence that live H. pylori infects atheromas, exacerbates atherosclerotic plaque development, and alters plasma lipid profiles independently of diet or hormonal status. Finally, socially subordinate animals relative to their dominant counterparts had a greater prevalence of H. pylori, suggesting a stress effect. The results indicate that early H. pylori eradication could prevent or delay development of cardiovascular disease.

An update on clonality: what smooth muscle cell type makes up the atherosclerotic plaque?

Almost 50 years ago, Earl Benditt and his son John described the clonality of the atherosclerotic plaque. This led Benditt to propose that the atherosclerotic lesion was a smooth muscle neoplasm, similar to the leiomyomata seen in the uterus of most women. Although the observation of clonality has been confirmed many times, interest in the idea that atherosclerosis might be a form of neoplasia waned because of the clinical success of treatments for hyperlipemia and because animal models have made great progress in understanding how lipid accumulates in the plaque and may lead to plaque rupture. Four advances have made it important to reconsider Benditt's observations. First, we now know that clonality is a property of normal tissue development. Second, this is even true in the vessel wall, where we now know that formation of clonal patches in that wall is part of the development of smooth muscle cells that make up the tunica media of arteries. Third, we know that the intima, the "soil" for development of the human atherosclerotic lesion, develops before the fatty lesions appear. Fourth, while the cells comprising this intima have been called "smooth muscle cells", we do not have a clear definition of cell type nor do we know if the initial accumulation is clonal. As a result, Benditt's hypothesis needs to be revisited in terms of changes in how we define smooth muscle cells and the quite distinct developmental origins of the cells that comprise the muscular coats of all arterial walls. Finally, since clonality of the lesions is real, the obvious questions are do these human tumors precede the development of atherosclerosis, how do the clones develop, what cell type gives rise to the clones, and in what ways do the clones provide the soil for development and natural history of atherosclerosis?

Utility of Nonhuman Primates in Substance Use Disorders Research

Substance use disorders (i.e., drug addiction) constitute a global and insidious public health issue. Preclinical biomedical research has been invaluable in elucidating the environmental, biological, and pharmacological determinants of drug abuse and in the process of developing innovative pharmacological and behavioral treatment strategies. For more than 70 years, nonhuman primates have been utilized as research subjects in biomedical research related to drug addiction. There are already several excellent published reviews highlighting species differences in both pharmacodynamics and pharmacokinetics between rodents and nonhuman primates in preclinical substance abuse research. Therefore, the aim of this review is to highlight three advantages of nonhuman primates as preclinical substance abuse research subjects. First, nonhuman primates offer technical advantages in experimental design compared to other laboratory animals that afford unique opportunities to promote preclinical-to-clinical translational research. Second, these technical advantages, coupled with the relatively long lifespan of nonhuman primates, allows for pairing longitudinal drug self-administration studies and noninvasive imaging technologies to elucidate the biological consequences of chronic drug exposure. Lastly, nonhuman primates offer advantages in the patterns of intravenous drug self-administration that have potential theoretical implications for both the neurobiological mechanisms of substance use disorder etiology and in the drug development process of pharmacotherapies for substance use disorders. We conclude with potential future research directions in which nonhuman primates would provide unique and valuable insights into the abuse of and addiction to novel psychoactive substances.

Premenopausal Reproductive Health Modulates Future Cardiovascular Risk - Comparative Evidence from Monkeys and Women

Coronary heart disease (CHD) remains the major cause of mortality among postmenopausal women living in industrialized countries. Several lines of evidence suggest that ovarian hormones (especially estrogen) protect the coronary arteries of premenopausal women. However, it is also known that women commonly experience disruptions in cyclic hormonal function during their reproductive years. In this perspective, we hypothesize that if regular, cyclic ovarian function affords protection against CHD, ovulatory abnormalities in young women may conversely promote the development of atherosclerosis (the pathobiological process underlying CHD) in the years prior to menopause and thus substantially increase the risk of subsequent heart disease. This hypothesis is supported by evidence from premenopausal nonhuman primates showing that relatively common, subclinical ovarian disruptions - as may be induced by psychosocial stress - are associated with the initiation and acceleration of coronary artery atherosclerosis. If extending to women, these findings would suggest that ovarian dysfunction is an early biomarker for CHD risk and, further, that primary prevention of CHD should begin during the premenopausal phase of life.

Functional Hypothalamic Amenorrhea: An Endocrine Society Clinical Practice Guideline

COSPONSORING ASSOCIATIONS

The American Society for Reproductive Medicine, the European Society of Endocrinology, and the Pediatric Endocrine Society. This guideline was funded by the Endocrine Society.

OBJECTIVE

To formulate clinical practice guidelines for the diagnosis and treatment of functional hypothalamic amenorrhea (FHA).

PARTICIPANTS

The participants include an Endocrine Society-appointed task force of eight experts, a methodologist, and a medical writer.

EVIDENCE

This evidence-based guideline was developed using the Grading of Recommendations, Assessment, Development, and Evaluation approach to describe the strength of recommendations and the quality of evidence. The task force commissioned two systematic reviews and used the best available evidence from other published systematic reviews and individual studies.

CONSENSUS PROCESS

One group meeting, several conference calls, and e-mail communications enabled consensus. Endocrine Society committees and members and cosponsoring organizations reviewed and commented on preliminary drafts of this guideline.

CONCLUSIONS

FHA is a form of chronic anovulation, not due to identifiable organic causes, but often associated with stress, weight loss, excessive exercise, or a combination thereof. Investigations should include assessment of systemic and endocrinologic etiologies, as FHA is a diagnosis of exclusion. A multidisciplinary treatment approach is necessary, including medical, dietary, and mental health support. Medical complications include, among others, bone loss and infertility, and appropriate therapies are under debate and investigation.

Dietary Factors and Cognitive Function in Poor Urban Settings

A significant body of evidence suggests that poor dietary intake is associated with reduced cognitive function. However, few studies have examined this relation in poor urban settings. Our brief review suggests that (a) higher overall diet quality may play a particularly important role in cognitive function among the poorest; and (b) greater vitamin E intake is related to better cognitive performance, at least in part, via fewer depressive symptoms. The broader recent literature strongly suggests the beneficial role of diet for learning and memory, and potentially synergistic influences on other cognitive domains. However, adherence to healthful diet among urban poor may be limited by factors such as cost and access. Here, we propose several potential moderators and mediators of diet-cognition relations among urban poor. Future studies should focus on the complex interplay among factors that influence the role of diet in cognitive function among poor, urban-dwelling persons.

The influence of facility and home pen design on the welfare of the laboratory-housed dog

We have an ethical and scientific obligation to Refine all aspects of the life of the laboratory-housed dog. Across industry there are many differences amongst facilities, home pen design and husbandry, as well as differences in features of the dogs such as strain, sex and scientific protocols. Understanding how these influence welfare, and hence scientific output is therefore critical. A significant proportion of dogs' lives are spent in the home pen and as such, the design can have a considerable impact on welfare. Although best practice guidelines exist, there is a paucity of empirical evidence to support the recommended Refinements and uptake varies across industry. In this study, we examine the effect of modern and traditional home pen design, overall facility design, husbandry, history of regulated procedures, strain and sex on welfare-indicating behaviours and mechanical pressure threshold. Six groups of dogs from two facilities (total n=46) were observed in the home pen and tested for mechanical pressure threshold. Dogs which were housed in a purpose-built modern facility or in a modern design home pen showed the fewest behavioural indicators of negative welfare (such as alert or pacing behaviours) and more indicators of positive welfare (such as resting) compared to those in a traditional home pen design or traditional facility. Welfare indicating behaviours did not vary consistently with strain, but male dogs showed more negative welfare indicating behaviours and had greater variation in these behaviours than females. Our findings showed more positive welfare indicating behaviours in dogs with higher mechanical pressure thresholds. We conclude that factors relating to the design of home pens and implementation of Refinements at the facility level have a significant positive impact on the welfare of laboratory-housed dogs, with a potential concomitant impact on scientific endpoints.

The Signature of Maternal Social Rank in Placenta Deoxyribonucleic Acid Methylation Profiles in Rhesus Monkeys

The effects of social status on human health can be modeled in captive cohorts of nonhuman primates. This study shows that maternal social rank is associated with broad changes in DNA methylation in placentae of rhesus monkeys (N = 10). Differentially methylated genes between social ranks are enriched in signaling pathways playing major roles in placenta physiology. Moreover, the authors found significant overlaps with genes whose expression was previously associated with social rank in adult rhesus monkeys (Tung et al., 2012) and whose methylation was associated with perinatal stress in newborn humans and rhesus monkeys (Nieratschker et al., 2014). These results are consistent with the hypothesis that system-wide epigenetic changes in multiple tissues are involved in long-term adaptations to the social environment.

Behavioral, emotional and neurobiological determinants of coronary heart disease risk in women

Women have more of the stress-related behavioral profile that has been linked to cardiovascular disease than men. For example, women double the rates of stress-related mental disorders such as depression and posttraumatic stress disorder (PTSD) than men, and have higher rates of exposure to adversity early in life. This profile may increase women's long-term risk of cardiometabolic conditions linked to stress, especially coronary heart disease (CHD). In addition to having a higher prevalence of psychosocial stressors, women may be more vulnerable to the adverse effects of these stressors on CHD, perhaps through altered neurobiological physiology. Emerging data suggest that young women are disproportionally susceptible to the adverse effects of stress on the risk of cardiovascular disease, both in terms of initiating the disease as well as worsening the prognosis in women who have already exhibited symptoms of the disease. Women's potential vulnerability to psychosocial stress could also help explain their higher propensity toward abnormal coronary vasomotion and microvascular disease compared with men.

Emotional triggering of cardiac dysfunction: the present and future

Mental stress and emotional arousal can act as triggers of acute myocardial infarction and other adverse cardiovascular outcomes. Experimental research examining mechanisms of the adverse interplay between mind and heart has led to the discovery of mental stress-induced cardiac dysfunction or myocardial ischemia (MSIMI). Evidence about the prevalence, clinical significance, and mechanistic bases of MSIMI outlines a wide range of central and peripheral bio-pathologic processes that are associated with emotions and behaviors. MSIMI is recognized as an integrated and intermediate biomarker underpinning the negative mind-heart interplay. Particularly, MSIMI research paves the way toward investigations aiming more specifically at recognizing the susceptibilities of individuals who are prone to respond adversely to the psycho-social-environmental stress. This article reviews recent literature on MSIMI research following the comprehensive review of Strike and Steptoe Eur Heart J 24:690-703, 2003. Further, this article outlines the main steps in the identification of the specific bio-pathologic manifestations of the cardiovascular system to emotional stress. Finally, a speculative description is provided of future directions in better searching for areas that may be critical targets in resolving adverse mind-heart interplays.

The effect of subjective social status on depressive thinking: An experimental examination

Subjective social status (SSS) predicts health outcomes above and beyond objective measures of social status. Both objective and subjective measures of social status are strongly related with depression. Cognitive mechanisms such as depressive cognitions, rumination, and a negative cognitive style are seen as both concomitant and antecedent to depression. This experiment examined the causal role of SSS in developing depressive thinking. Participants were randomly assigned to a low and a high status group and followed a manipulation procedure targeting their SSS. Depressive thinking was subsequently assessed by depressive cognitions, stress-reactive state rumination and negative cognitive style. Low status participants exhibited higher levels of depressive cognitions and rumination compared to their high status counterparts, but both groups did not differ regarding their cognitive style. Findings support the causal nature of the relationship between SSS and depressive thinking. Several mechanisms of how low SSS may lead to depression are discussed.

The Mortality Rate of Myocardial Infraction Patients With and Without Opium Dependen

Background:

Myocardial infarction (MI) is a heart condition caused by the suspension of blood circulation in a part of the myocardium. There are different risk factors contributing to a heart attack. Some believe that endorphins and endogenous opioids play an important role in causing MIs.

Objectives:

This study intended to determine the relationship between opium dependency and mortality rate among patients with MI.

Patients and Methods:

This retrospective study investigated patients who had MI for the first time and were hospitalized in the coronary care unit (CCU) of Khatamolanbia hospital in Zahedan, Iran, from 2007 to 2010. These patients were either opium dependent or not. Four hundred patients were selected. The patients’ possibilities of death and re-hospitalization after the first MI were confirmed over the phone. Data was analyzed through t-test and chi-squared test.

Results:

Of all the patients, 19.5% were opium-dependent. The mortality rate in the non-opium-dependent group was 5.9%, while in the dependent group this rate was 11.5% (P = 0.072). The number of re-hospitalizations due to heart problems was higher in the opium-dependent patients (P < 0.001).

Conclusions:

There was no meaningful relationship between the mortality rate of patients with MI who were either opium-dependent or non-opium-dependent. The number of re-hospitalizations due to heart problems was meaningfully higher in the opium-dependent patients; hence, educating people and training them on the destructive effects of opium, specifically in patients with heart conditions is highly recommended.

Computing a Synthetic Chronic Psychosocial Stress Measurement in Multiple Datasets and its Application in the Replication of G × E Interactions of the EBF1 Gene

Chronic psychosocial stress adversely affects health and is associated with the development of disease [Williams, 2008]. Systematic epidemiological and genetic studies are needed to uncover genetic variants that interact with stress to modify metabolic responses across the life cycle that are the proximal contributors to the development of cardiovascular disease and precipitation of acute clinical events. Among the central challenges in the field are to perform and replicate gene-by-environment (G × E) studies. The challenge of measurement of individual experience of psychosocial stress is magnified in this context. Although many research datasets exist that contain genotyping and disease-related data, measures of psychosocial stress are often either absent or vary substantially across studies. In this paper, we provide an algorithm to create a synthetic measure of chronic psychosocial stress across multiple datasets, applying a consistent criterion that uses proxy indicators of stress components. We validated the computed scores of chronic psychosocial stress by observing moderately strong and significant correlations with the self-rated chronic psychosocial stress in the Multi-Ethnic Study of Atherosclerosis Cohort (Rho = 0.23, P < 0.0001) and with the measures of depressive symptoms in five datasets (Rho = 0.15-0.42, Ps = 0.005 to <0.0001) and by comparing the distributions of the self-rated and computed measures. Finally, we demonstrate the utility of this computed chronic psychosocial stress variable by providing three additional replications of our previous finding of gene-by-stress interaction with central obesity traits [Singh et al., 2015].

Social inequalities in health in nonhuman primates

Overall health has been linked to socioeconomic status, with the gap between social strata increasing each year. Studying the impact of social position on health and biological functioning in nonhuman primates has allowed researchers to model the human condition while avoiding ethical complexities or other difficulties characteristic of human studies. Using female cynomolgus macaques (Macaca fascicularis), our lab has examined the link between social status and stress for 30 years. Female nonhuman primates are especially sensitive to social stressors which can deleteriously affect reproductive health, leading to harmful consequences to their overall health. Subordinates have lower progesterone concentrations during the luteal phase of menstrual cycle, which is indicative of absence or impairment of ovulation. Subordinate animals receive more aggression, less affiliative attention, and are more likely to exhibit depressive behaviors. They also express higher stress-related biomarkers such as increased heart rates and lower mean cortisol. While no differences in body weight between dominant and subordinate animals are observed, subordinates have lower bone density and more visceral fat than their dominant counterparts. The latter increases risk for developing inflammatory diseases. Differences are also observed in neurological and autonomic function. A growing body of data suggests that diet composition may amplify or diminish physiological stress responses which have deleterious effects on health. More experimental investigation of the health effects of diet pattern is needed to further elucidate these differences in an ongoing search to find realistic and long-term solutions to the declining health of individuals living across the ever widening socioeconomic spectrum.

Why primate models matter

Research involving nonhuman primates (NHPs) has played a vital role in many of the medical and scientific advances of the past century. NHPs are used because of their similarity to humans in physiology, neuroanatomy, reproduction, development, cognition, and social complexity-yet it is these very similarities that make the use of NHPs in biomedical research a considered decision. As primate researchers, we feel an obligation and responsibility to present the facts concerning why primates are used in various areas of biomedical research. Recent decisions in the United States, including the phasing out of chimpanzees in research by the National Institutes of Health and the pending closure of the New England Primate Research Center, illustrate to us the critical importance of conveying why continued research with primates is needed. Here, we review key areas in biomedicine where primate models have been, and continue to be, essential for advancing fundamental knowledge in biomedical and biological research.

Stress and the reproductive axis

There exists a reciprocal relationship between the hypothalamic-pituitary-adrenal (HPA) and the hypothalamic-pituitary-gonadal (HPG) axes, wherein the activation of one affects the function of the other and vice versa. For example, both testosterone and oestrogen modulate the response of the HPA axis, whereas activation of the stress axis, especially activation that is repeating or chronic, has an inhibitory effect upon oestrogen and testosterone secretion. Alterations in maternal care can produce significant effects on both HPG and HPA physiology, as well as behaviour in the offspring at adulthood. For example, changes in reproductive behaviour induced by altered maternal care may alter the expression of sex hormone receptors such as oestrogen receptor (ER)α that govern sexual behaviour, and may be particularly important in determining the sexual strategies utilised by females. Stress in adulthood continues to mediate HPG activity in females through activation of a sympathetic neural pathway originating in the hypothalamus and releasing norepinephrine into the ovary, which produces a noncyclic anovulatory ovary that develops cysts. In the opposite direction, sex differences and sex steroid hormones regulate the HPA axis. For example, although serotonin (5-HT) has a stimulatory effect on the HPA axis in humans and rodents that is mediated by the 5-HT1A receptor, only male rodents respond to 5-HT1A antagonism to show increased corticosterone responses to stress. Furthermore, oestrogen appears to decrease 5-HT1A receptor function at presynaptic sites, yet increases 5-HT1A receptor expression at postsynaptic sites. These mechanisms could explain the heightened stress HPA axis responses in females compared to males. Studies on female rhesus macaques show that chronic stress in socially subordinate female monkeys produces a distinct behavioural phenotype that is largely unaffected by oestrogen, a hyporesponsive HPA axis that is hypersensitive to the modulating effects of oestrogen, and changes in 5-HT1A receptor binding in the hippocampus and hypothalamus of social subordinate female monkeys that are restored or inverted by oestrogen replacement. This review summarises all of these studies, emphasising the profound effect that the interaction of the reproductive and stress axes may have on human reproductive health and emotional wellbeing.

Oestradiol differentially influences feeding behaviour depending on diet composition in female rhesus monkeys

In females, cyclical changes in the ovarian hormone oestradiol are known to modulate feeding behaviour. However, what is less clear is how these behavioural effects of oestradiol are modified by the macronutrient content of a diet. In the present study, we report data showing that oestradiol treatment results in both significantly smaller meals and a reduced total calorie intake in ovariectomised, socially-housed female rhesus macaques when only chow diet is available. Conversely, during a choice dietary condition where both palatable and chow options are available, oestradiol treatment had no observable, attenuating effect on calorie intake. During this choice dietary phase, all animals consumed more of the palatable diet than chow diet; however, oestradiol treatment appeared to further increase preference for the palatable diet. Finally, oestradiol treatment increased snacking behaviour (i.e. the consumption of calories outside of empirically defined meals), regardless of diet condition. These findings illustrate how oestradiol differentially influences feeding behaviour depending on the dietary environment and provides a framework in which we can begin to examine the mechanisms underlying these observed changes.

Oxytocin administration attenuates atherosclerosis and inflammation in Watanabe Heritable Hyperlipidemic rabbits

Oxytocin (OT) is a neurohypophyseal peptide traditionally associated with female reproductive functioning, and more recently with prosocial behavior. OT and its receptor are also expressed in the heart and vascular tissue and play a role in cardiovascular homeostasis. In vitro, it has been demonstrated that OT decreases NADPH-dependent superoxide production and pro-inflammatory cytokine release from vascular endothelial cells and macrophages, suggesting that OT may attenuate pathophysiological processes involved with atherosclerotic lesion formation. The present study sought to determine the effect of chronic exogenous OT administration on inflammation and atherosclerosis in an animal model of dyslipidemia and atherosclerosis, the Watanabe Heritable Hyperlipidemic (WHHL) rabbit. Twenty-two, 3-month-old WHHLs were surgically implanted with osmotic mini-pumps containing OT (n=11) or vehicle (n=11), and then were individually housed for the entire study. Blood and 24-h urine samples were taken at baseline and after 8 (midpoint) and 16 (endpoint) weeks of treatment. At endpoint, the aortas and visceral fat samples were dissected and stored for analyses. There were no group differences in body weight, serum lipids, plasma/urinary measures of oxidative stress, plasma cortisol or urinary catecholamines over the 16-week treatment. OT-treated animals exhibited significantly lower plasma C-reactive protein levels at midpoint and endpoint and developed significantly less atherosclerosis in the thoracic aorta relative to vehicle control animals at endpoint (p<0.05). Cytokine gene expression from visceral adipose tissue samples suggested that there was a decrease in adipose tissue inflammation in the OT-treated group compared to the vehicle control group, however these differences were not statistically significant. These results suggest that chronic peripheral OT administration can inhibit inflammation and atherosclerotic lesion development.

Stress and cardiovascular disease: an update on current knowledge

Considerable progress has been made during the past decade in research on cardiovascular effects of stress. Early-life stressors, such as childhood abuse and early socioeconomic adversity, are linked to increased cardiovascular morbidity in adulthood. Our updated meta-analyses of prospective studies published until 2011 show a 1.5-fold (95% confidence interval 1.2-1.9) increased risk of coronary heart disease among adults experiencing social isolation and a 1.3-fold (1.2-1.5) excess risk for workplace stress; adverse metabolic changes are one of the underlying plausible mechanisms. Stress, anger, and depressed mood can act as acute triggers of major cardiac events; the pooled relative risk of acute coronary syndrome onset being preceded by stress is 2.5 (1.8-3.5) in case-crossover studies. Stress is also implicated in the prognosis of cardiovascular disease and in the development of stress (takotsubo) cardiomyopathy. A major challenge over the next decade is to incorporate stress processes into the mainstream of cardiovascular pathophysiological research and understanding.

Social and emotional predictors of the tempo of puberty in female rhesus monkeys

A cascade of neuroendocrine events regulates the initiation and progression of female puberty. However, the factors that determine the timing of these events across individuals are still uncertain. While the consequences of puberty on subsequent emotional development and adult behavior have received significant attention, what is less understood are the social and environmental factors that actually alter the initiation and progression of puberty. In order to more fully understand what factors influence pubertal timing in females, the present study quantified social and emotional behavior; stress physiology; and growth and activity measures in juvenile female rhesus monkeys to determine what best predicts eventual puberty. Based on previous reports, we hypothesized that increased agonistic behavior resulting from subordinate status in their natal group, in combination with slowed growth, reduced prosocial behavior, and increased emotional reactivity would predict delayed puberty. The analyses were restricted to behavioral and physiological measures obtained prior to the onset of puberty, defined as menarche. Together, our findings indicate that higher rates of aggression but lower rates of submission received from group mates; slower weight gain; and greater emotional reactivity, evidenced by higher anxiety, distress and appeasing behaviors, and lower cortisol responsivity in response to a potentially threatening situation, predicts delayed puberty. Together the combination of these variables accounted for 58% of the variance in the age of menarche, 71% in age at first ovulation, and 45% in the duration of adolescent sterility. While early puberty may be more advantageous for the individual from a fertility standpoint, it presents significant health risks, including increased risk for a number of estrogen dependent cancers and as well as the emergence of mood disorders during adulthood. On the other hand, it is possible that increased emotional reactivity associated with delayed puberty could persist, increasing the risk for emotional dysregulation to socially challenging situations. The data argue for prospective studies that will determine how emotional reactivity shown to be important for pubertal timing is affected by early social experience and temperament, and how these stress-related variables contribute to body weight accumulation, affecting the neuroendocrine regulation of puberty.

Social subordination produces distinct stress-related phenotypes in female rhesus monkeys

Social subordination in female macaques is imposed by harassment and the threat of aggression and produces reduced control over one's social and physical environment and a dysregulation of the limbic-hypothalamic-pituitary-adrenal axis resembling that observed in people suffering from psychopathologies. These effects support the contention that this particular animal model is an ethologically relevant paradigm in which to investigate the etiology of stress-induced psychological illness related to women. Here, we sought to expand this model by performing a discriminate analysis (DA) on 33 variables within three domains; behavioral, metabolic/anthropomorphic, and neuroendocrine, collected from socially housed female rhesus monkeys in order to assess whether exposure to social subordination produces a distinct phenotype. A receiver operating characteristic (ROC) curve was also calculated to determine each domain's classification accuracy. DA found significant markers within each domain that differentiated dominant and subordinate females. Subordinate females received more aggression, showed more submissive behavior, and received less of affiliation from others than did dominant females. Metabolic differences included increased leptin, and reduced adiponectin in dominant compared to subordinate females. Dominant females exhibited increased sensitivity to hormonal stimulation with higher serum LH in response to estradiol, cortisol in response to ACTH, and increased glucocorticoid negative feedback. Serum oxytocin, CSF DOPAC and serum PACAP were all significantly higher in dominant females. ROC curve analysis accurately predicted social status in all three domains. Results suggest that socially house rhesus monkeys represent a cogent animal model in which to study the physiology and behavioral consequences of chronic psychosocial stress in humans.

Daily psychological demands are associated with 6-year progression of carotid artery atherosclerosis: the Pittsburgh Healthy Heart Project

OBJECTIVE

We examine associations between the perception of ongoing psychological demands by ecological momentary assessment (EMA) and 6-year changes in carotid artery atherosclerosis by ultrasonography.

METHODS

A total of 270 initially healthy participants collected ambulatory blood pressure (ABP) and recorded their daily experiences, using electronic diaries, during two 3-day periods. Mean intima-media thickness (IMT) and plaque were assessed in the carotid arteries using B-mode ultrasound at baseline and again during a 6-year follow-up (mean follow-up duration = 73 months).

RESULTS

Among those who had no exposure to antihypertensive medications during the course of follow-up (n = 192), daily psychological demands were associated with greater progression of IMT as well as plaque, after adjusting for demographic and risk factor covariates. Associations between demands and plaque change were partially accounted for by ABP differences among those reporting high demands. Among those who were employed at baseline (n = 117), 6-year IMT changes were more strongly associated with ratings of daily demands than with traditional measures of occupational stress.

CONCLUSIONS

These data support the role of psychological demands as a correlate of subclinical atherosclerotic progression, they point to ABP as a potential mechanism facilitating these effects, and they highlight the utility of EMA measures for capturing daily psychological demands with potential effects on health.

The monkey puzzle: a systematic review of studies of stress, social hierarchies, and heart disease in monkeys

BACKGROUND

It is often suggested that psychosocial factors, such as stress, or one's social position, may play an important role in producing social gradients in human disease. Evidence in favour of this model of health inequalities has relied, in part, on studies of the health effects of the natural social hierarchies found among non-human primates. This study aimed to assess the strength of this evidence.

METHODOLOGY/PRINCIPAL FINDINGS

A systematic review was carried out to identify all studies of psychosocial factors and coronary artery disease (CAD) in non-human primates. We searched databases (MEDLINE, PsycInfo, EMBASE, and Primatelit from inception to November 2010) to identify experimental and observational studies of the impact of social reorganisation, social instability, and disruption of dominance hierarchies on primate CAD outcomes. We also handsearched bibliographies and examined the citations to those studies in public health articles. Fourteen studies were found which presented evidence on CAD and social status and/or psychosocial stress. These suggested that the association between social status and disease may be sex-specific: in female monkeys dominant status may be protective, with subordinate females having a greater extent of atherosclerosis. In male monkeys the reverse may be the case.

CONCLUSIONS/SIGNIFICANCE

Overall, non-human primate studies present only limited evidence for an association between social status and CAD, Despite this, there is selective citation of individual non-human primate studies in reviews and commentaries relating to human disease aetiology. Such generalisation of data from monkey studies to human societies does not appear warranted.

Behavioral and neurobiological characteristics of social stress versus depression in nonhuman primates

The focus of the review is on the behavioral and physiological manifestations of stress versus depression. The purpose of the review is to evaluate the conceptual approach of using stress models as surrogates for depression. Social stress and depression have many characteristics in common and promote each other. Both have adverse effects on social relationships and the quality of life, and increase risk of other diseases. However, they are not the same constructs. In human and nonhuman primates, the behavior and neurobiology of stressed individuals differ from that of depressed individuals. Some similarities in stress physiology in socially stressed and depressed individuals have been used to support the use of stressed animals as models of depression, and much has been learned from stress models of depression. However, the studies reviewed here also suggest that the depressed state also has different characteristics than the stressed state, and studying the differences may be important to furthering our understanding of each of these constructs as well as their mutual relationship.

The effects of repeated handling and corticosterone treatment on behavior in an amphibian (Ocoee salamander: Desmognathus ocoee)

Exposure to unpredictable challenges triggers a stress response that helps an animal cope by ensuring energy availability and increasing expression of anti-predator behaviors. At the same time, stress responses typically suppress activities non-essential to immediate survival, such as growth and reproduction. Glucocorticoid hormones are key mediators of the stress response. We measured the effects of repeated exposure to a handling stressor and repeated elevation of plasma levels of the glucocorticoid hormone, corticosterone (CORT) in a terrestrial salamander, Desmognathus ocoee. Subjects were handled daily or treated every day with a dermal patch containing CORT. Compared to control treatments, chronic handling and treatment with CORT both resulted in decreased body weight. Repeated handling, but not treatment with CORT, reduced feeding in females and activity in both males and females. Treatments had no effect on white blood cell differentials. Despite a nonsignificant trend for courtship to be delayed in handled animals, most salamanders in all treatment groups courted and mated. Courtship and mating may be relatively resistant to the effects of repeated handling and elevated plasma CORT because courtship and mating are energetically inexpensive in this species.

Impairment of ovarian function and associated health-related abnormalities are attributable to low social status in premenopausal monkeys and not mitigated by a high-isoflavone soy diet

BACKGROUND

Psychological stress may impair premenopausal ovarian function and contribute to risk for chronic disease. Soy isoflavones may also influence ovarian function and affect health. Here, we report the effects of a psychological stressor (subordinate social status) and dietary soy on reproductive function and related health indices in female monkeys. We hypothesized that reproductive compromise and adverse health outcomes would be induced in subordinate when compared with dominant monkeys and be mitigated by exposure to soy.

METHODS

Subjects were 95 adult cynomolgus monkeys (Macaca fascicularis) housed in social groups of five or six. Animals consumed a soy-free, animal protein-based diet during an 8-month Baseline phase and then, during a 32-month Treatment phase, consumed either the baseline diet or an identical diet that substituted high-isoflavone soy protein for animal protein.

RESULTS

Across more than 1200 menstrual cycles, subordinate monkeys consistently exhibited ovarian impairment [increased cycle length (P < 0.02) and variability (P < 0.02) and reduced levels of progesterone (P < 0.04) and estradiol (P < 0.04)]. Subordinate status was confirmed behaviorally and was associated with elevated cortisol (P < 0.04) and relative osteopenia (P < 0.05). Consumption of the soy diet had no significant effects.

CONCLUSIONS

(i) Psychological stress adversely affects ovarian function and related health indices in a well-accepted animal model of women's health; (ii) Similar effects may extend to women experiencing reproductive impairment of psychogenic origin; (iii) soy protein and isoflavones neither exacerbate nor mitigate the effects of an adverse psychosocial environment; and (iv) this study was limited by an inability to investigate the genetic and developmental determinants of social status.

The effect of diet and cardiovascular risk on ovarian aging in cynomolgus monkeys (Macaca fascicularis)

OBJECTIVE

The aim of this study was to determine the relationships among dietary protein source, cardiovascular risk, reproductive hormones, and ovarian aging.

METHODS

Adult female cynomolgus monkeys (Macaca fascicularis) were assigned randomly to one of two diets containing saturated fat and cholesterol, differing only by protein source: (1) casein-lactalbumin (n = 29) or (2) soy protein with isoflavones (n = 32). Cardiovascular risk markers and reproductive hormones were measured at baseline and after 32 months of treatment, at which time the ovaries were removed and serially sectioned and ovarian follicles were counted in every 100th section.

RESULTS

Casein-lactalbumin-fed monkeys had fewer primordial, primary, and secondary follicles (all P values < 0.05) than did their soy-fed counterparts. Antimüllerian hormone was significantly correlated with all follicle types (r values > or = 0.66, P < 0.001) for casein-fed monkeys and was significantly correlated with primary (rsoy = 0.47, P = 0.005) and secondary (rsoy = 0.45, P = 0.007) follicles in soy-fed monkeys. No significant associations were seen between any of the other reproductive hormones measured and follicle counts. Casein-lactalbumin-fed monkeys had a more atherogenic lipoprotein profile and increased atherosclerosis extent (P < 0.05), but despite these differences in cardiovascular risk between monkeys fed with casein-lactalbumin and monkeys fed with soy, none of the individual cardiovascular risk markers measured in this study explained the relationship between dietary protein source and follicle counts (linear regression, all P values > 0.05).

CONCLUSIONS

Diet influences the rate of follicular depletion in cynomolgus macaques; however, the mechanism for this effect remains undetermined.

Neurobiological pathways linking socioeconomic position and health

Across individuals, risk for poor health varies inversely with socioeconomic position (SEP). The pathways by which SEP affects health have been viewed from many epidemiological perspectives. Central to these perspectives is the notion that socioeconomic health disparities arise from an interplay between nested, recursive, and cumulative environmental, social, familial, psychological, behavioral, and physiological processes that unfold over the life span. Epidemiological perspectives on socioeconomic health disparities, however, have not yet formally integrated emerging findings from neuropharmacological, molecular genetic, and neuroimaging studies demonstrating that indicators of SEP relate to patterns of brain neurotransmission, brain morphology, and brain functionality implicated in the etiology of chronic medical conditions and psychological disorders. Here, we survey these emerging findings and consider how future neurobiological studies in this area can enhance our understanding of the pathways by which different dimensions of SEP become embodied by the brain to influence health throughout life.

Social stress, visceral obesity, and coronary artery atherosclerosis: product of a primate adaptation

Abdominal obesity is prevalent and often accompanied by an array of metabolic perturbations including elevated blood pressure, dyslipidemia, impaired glucose tolerance or insulin resistance, a prothrombotic state, and a proinflammatory state, together referred to as the metabolic syndrome. The metabolic syndrome greatly increases coronary heart disease (CHD) risk. Social stress also increases CHD although the mechanisms through which this occurs are not completely understood. Chronic stress may result in sustained glucocorticoid production, which is thought to promote visceral obesity. Thus, one hypothesis is that social stress may cause visceral fat deposition and the metabolic syndrome, which, in turn increases CHD. CHD is caused by coronary artery atherosclerosis (CAA) and its sequelae. Cynomolgus monkeys (Macaca fascicularis) are a well-established models of CAA. Social subordination may be stressful to cynomolgus monkeys and result in hypercortisolemia and exacerbated CAA in females. Herein is reviewed a body of literature which suggests that social stress increases visceral fat deposition in cynomolgus monkeys, that subordinate females are more likely than dominants to have visceral obesity, that females with visceral obesity have behavioral and physiological characteristics consistent with a stressed state, and that females with high ratios of visceral to subcutaneous abdominal fat develop more CAA. While these relationships have been most extensively studied in cynomolgus macaques, obesity-related metabolic disturbances are also observed in other primate species. Taken together, these observations support the view that the current obesity epidemic is the result of a primate adaptation involving the coevolution with encephalization of elaborate physiological systems to protect against starvation and defend stored body fat in order to feed a large and metabolically demanding brain. Social stress may be engaging these same physiological systems, increasing the visceral deposition of fat and its sequelae, which increase CHD risk.