The effects of age and cytomegalovirus on markers of inflammation and lymphocyte populations in captive baboons

Female baboon adrenal zona fasciculata and zona reticularis regulatory and functional proteins decrease across the life course

Debate exists on life-course adrenocortical zonal function trajectories. Rapid, phasic blood steroid concentration changes, such as circadian rhythms and acute stress responses, complicate quantification. To avoid pitfalls and account for life-stage changes in adrenocortical activity indices, we quantified zonae fasciculata (ZF) and reticularis (ZR) across the life-course, by immunohistochemistry of key regulatory and functional proteins. In 28 female baboon adrenals (7.5-22.1 years), we quantified 12 key proteins involved in cell metabolism, division, proliferation, steroidogenesis (including steroid acute regulatory protein, StAR), oxidative stress, and glucocorticoid and mitochondrial function. Life-course abundance of ten ZF proteins decreased with age. Cell cycle inhibitor and oxidative stress markers increased. Seven of the 12 proteins changed in the same direction for ZR and ZF. Importantly, ZF StAR decreased, while ZR StAR was unchanged. Findings indicate ZF function decreased, and less markedly ZR function, with age. Causes and aging consequences of these changes remain to be determined.

Epidemiological characteristics and spatio-temporal aggregation of severe fever with thrombocytopenia syndrome in Jinan City, China, 2018-2022

BACKGROUND

Severe fever with thrombocytopenia syndrome (SFTS) has become a significant public health issue in Jinan City. However, the analysis of epidemiological characteristics and spatio-temporal clustering of SFTS in Jinan has not been studied yet.

METHODS

SFTS data from 2018-2022 in Jinan City were obtained from the China Information System for Disease Control and Prevention. Global spatial autocorrelation and local spatial autocorrelation analyses were performed using ArcGIS 10.2 software, and spatiotemporal hotspot area detection was carried out using SatScan 9.6 software.

RESULTS

Between 2018 and 2022, 680 SFTS cases were reported in Jinan City, resulting in 53 deaths and an average case fatality rate of 7.8%. 99.0% of cases occurred between April and October, 91.9% individuals were over 50 years old, and 87.79% were primarily farmers. A positive spatial correlation of SFTS in Jinan was observed (Moran's I value between 0.135-0.197, P<0.001), indicating spatial aggregation, primarily in Licheng, Zhangqiu, Laiwu, and Gangcheng districts in southeastern Jinan. Spatiotemporal scanning detected one class I and two class II aggregation areas, with the class I aggregation area (RR = 5.66, LLR = 192.547, P<0.001) locating in southeastern Jinan City, comprising 31 towns/streets, and an aggregation time from 13 May 2020 to 13 October 2022.

CONCLUSION

Spatial and temporal aggregation of SFTS is evident in Jinan. Based on the spatial and temporal distribution and epidemiological characteristics, prevention and control measures such as public education, monitoring, and training should target key populations in high-incidence epidemic areas.

Developmental Programming-Aging Interactions Have Sex-Specific and Developmental Stage of Exposure Outcomes on Life Course Circulating Corticosterone and Dehydroepiandrosterone (DHEA) Concentrations in Rats Exposed to Maternal Protein-Restricted Diets

The steroids corticosterone and dehydroepiandrosterone (DHEA) perform multiple life course functions. Rodent life-course circulating corticosterone and DHEA trajectories are unknown. We studied life course basal corticosterone and DHEA in offspring of rats fed protein-restricted (10% protein, R) or control (20% protein, C), pregnancy diet first letter, and/or lactation second letter, producing four offspring groups-CC, RR, CR, and RC. We hypothesize that 1. maternal diet programs are sexually dimorphic, offspring life course steroid concentrations, and 2. an aging-related steroid will fall. Both changes differ with the plastic developmental period offspring experienced R, fetal life or postnatally, pre-weaning. Corticosterone was measured by radioimmunoassay and DHEA by ELISA. Steroid trajectories were evaluated by quadratic analysis. Female corticosterone was higher than male in all groups. Male and female corticosterone were highest in RR, peaked at 450 days, and fell thereafter. DHEA declined with aging in all-male groups. DHEA: corticosterone fell in three male groups but increased in all-female groups with age. In conclusion, life course and sexually dimorphic steroid developmental programming-aging interactions may explain differences in steroid studies at different life stages and between colonies experiencing different early-life programming. These data support our hypotheses of sex and programming influences and aging-related fall in rat life course serum steroids. Life course studies should address developmental programming-aging interactions.

Immunosenescence and inflammaging in the aged horse

The equine population in the United States and worldwide now includes a higher percentage of geriatric horses than ever previously recorded, and as methods to treat and manage elderly equids are developed and refined, this aging population will likely continue to expand. A better understanding of how horses age and the effect of age on immunity and disease susceptibility is needed to enable targeted preventative healthcare strategies for aged horses. This review article outlines the current state of knowledge regarding the effect of aging on immunity, vaccine responsiveness, and disease risk in the horse, highlighting similarities and differences to what is observed in aged humans. Horses show similar but milder age-related alterations in immune function to those reported in people. Decreases in lymphocyte proliferation and antibody production and diminished response to vaccination have all been documented in elderly horses, however, increased risk of infectious disease is not commonly reported. Aged horses also show evidence of a proinflammatory state (inflammaging) yet appear less susceptible to the chronic diseases of people for which inflammation is a risk factor. Information is currently lacking as to why the horse does not experience the same risk of age-related disease (e.g., cancer, heart disease, neurodegeneration) as people, although a lack of negative lifestyle habits, differences in diet, exercise, genetics and physiology may all contribute to improved health outcomes in the older horse.

Are the Healthy Vulnerable? Cytomegalovirus Seropositivity in Healthy Adults Is Associated With Accelerated Epigenetic Age and Immune Dysregulation

BACKGROUND

Evaluating age as a risk factor for susceptibility to infectious diseases, particularly coronavirus disease 2019 (COVID-19), is critical. Cytomegalovirus (CMV) serologic prevalence increases with age and associates with inflammatory-mediated diseases in the elderly. However, little is known regarding the subclinical impact of CMV and risk it poses to healthy older adults. Prior to the COVID-19 pandemic we conducted a study to determine the association of CMV to biologic age and immune dysregulation.

METHODS

Community-dwelling, healthy adults older than 60 years were evaluated using DNA methylation assays to define epigenetic age (EpiAge) and T-cell immunophenotyping to assess immune dysregulation.

RESULTS

All subjects were healthy and asymptomatic. Those CMV seropositive had more lymphocytes, CD8 T cells, CD28- T cells, decreased CD4:CD8 cell ratios, and had higher average EpiAge (65.34 years) than those CMV seronegative (59.53 years). Decreased percent CD4 (P = .003) and numbers of CD4 T cells (P = .0199) correlated with increased EpiAge.

CONCLUSIONS

Our novel findings distinguish altered immunity in the elderly based on CMV status. Chronic CMV infection in healthy, older adults is associated with indicators of immune dysregulation, both of which correlate to differences in EpiAge.

Rodent studies of developmental programming and ageing mechanisms: Special issue: In utero and early life programming of ageing and disease

Compelling evidence exists indicating that developmental programming influences ageing. Programming alters life-course phenotype in multiple organs, predisposing to diseases such as diabetes, obesity and cardiovascular disease that shorten lifespan. This review describes studies in rodents, the most commonly studied species, addressing interactions of programming challenges with ageing. We first consider ageing and programming of insulin function that has been clearly shown to decrease with age. It is important to evaluate ageing in pancreatic islets isolated from other systems. Studies discussed show premature pancreatic islet ageing resulting from both maternal under- and overnutrition. New ways to determine programming of adipose tissue and effects on fat storage are explored. Oxidative stress is a major factor that regulates ageing in tissues. Oxidative stress is discussed in relation to reproductive and cardiovascular ageing. Premature ageing is associated with both low and high glucocorticoid function. Both over and undernutrition have offspring sex-specific programming effects on life-course glucocorticoid concentrations. Evidence is provided that maternal age at conception affects offspring endocrine and metabolism ageing. Finally, the importance of matching foetal nutrition and energy availability with composition and energy content in the post-weaning diet is demonstrated. This mismatch can lead to a greatly shortened lifespan. General principles are discussed throughout. For example, sexual dimorphism of age-related outcomes can be marked. Accelerated ageing occurs early in life. Improving knowledge on programming ageing interactions will improve health span as well as lifespan. Finally, there are considerable similarities in outcomes programmed by maternal undernutrition and overnutrition.

Effects of Chronic Viral Infection on Lymphocyte Populations in Middle-aged Baboons (Papio anubis)

Aging of the immune system is characterized by the loss of naïve T-cells, increased inflammation, and immune function impairment. Chronic infection with cytomegalovirus is thought to play a role in age-related changes in immunity. Therefore, to assess the effect of pathogens such as cytomegalovirus on the immune system, we determined lymphocyte populations and inflammatory markers over a 3-y period in captive, middle-age baboons, with various exposure to pathogens and shedding pressure. Groups included SPF (i.e., pathogen-negative; n = 14); large-group, conventionally housed (CONV LG; pathogen- positive; n = 14), and small-group, conventionally housed (CONV SM; pathogen-positive; n = 7). All baboon groups showed a decrease in CD45RA+ CD28+ (i.e., naive) cells over time during middle age, but the rate of decline appeared faster in CONV LG baboons than in the other groups. In addition, the reduction in CD45RA+ CD28+ cells in the CONV LG baboons coincided with higher IgG levels against baboon cytomegalovirus, increased serum cortisol concentration, and a greater inflammatory phenotype. The results of this project support a role for cytomegalovirus infection in immune system alterations in middle-aged baboons.

The nonhuman primate hypothalamo-pituitary-adrenal axis is an orchestrator of programming-aging interactions: role of nutrition

Developmental programming alters life-course multi-organ function and significantly affects life-course health. Recently, interest has developed in how programming may influence the rate of aging. This review describes interactions of nutrition and programming-aging interactions in hypothalamo-pituitary-adrenal (HPA) development and function from fetal development to old age. A full picture of these interactions requires data on levels of HPA activity relating to the hypothalamic, adrenal cortical, circulating blood, and peripheral cortisol metabolism. Data are provided from studies on our baboon, nonhuman primate model both across the normal life course and in offspring of maternal baboons who were moderately undernourished by a global 30% diet reduction during pregnancy and lactation. Sex differences in offspring outcomes in response to similar challenges are described. The data clearly show programming of increased HPA axis activity by moderate maternal undernutrition. Increased postnatal circulating cortisol concentrations are related to accelerated aging of the brain and cardiovascular systems. Future studies should address peripheral cortisol production and the influence of aging advantage in females. These data support the view that the HPA is an orchestrator of interactions of programming-aging mechanisms.

Mini-review: Aging of the neuroendocrine system: Insights from nonhuman primate models

The neuroendocrine system (NES) plays a crucial role in synchronizing the physiology and behavior of the whole organism in response to environmental constraints. The NES consists of a hypothalamic-pituitary-target organ axis that acts in coordination to regulate growth, reproduction, stress and basal metabolism. The growth (or somatotropic), hypothalamic-pituitary-gonadal (HPG), hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-thyroid (HPT) axes are therefore finely tuned by the hypothalamus through the successive release of hypothalamic and pituitary hormones to control the downstream physiological functions. These functions rely on a complex set of mechanisms requiring tight synchronization between peripheral organs and the hypothalamic-pituitary complex, whose functionality can be altered during aging. Here, we review the results of research on the effects of aging on the NES of nonhuman primate (NHP) species in wild and captive conditions. A focus on the age-related dysregulation of the master circadian pacemaker, which, in turn, alters the synchronization of the NES with the organism environment, is proposed. Finally, practical and ethical considerations of using NHP models to test the effects of nutrition-based or hormonal treatments to combat the deterioration of the NES are discussed.

Impact of Cytomegalovirus Disease on New-Onset Type 2 Diabetes Mellitus: Population-Based Matched Case-Control Cohort Study

BACKGROUND

A latent cytomegalovirus (CMV) cause chronic inflammation through undesirable inflation of cell-mediated immune response. CMV immunoglobulin G has been associated with cardiovascular disease and type 1 diabetes mellitus. We evaluated impact of CMV diseases on new-onset type 2 diabetes mellitus (T2DM).

METHODS

From the Korean Health Insurance Review and Assessment Service claim database of entire population with 50 million, we retrieved 576 adult case group with CMV diseases diagnosed with International Statistical Classification of Diseases and Related-Health Problems 10th Revision (ICD-10) B25 code between 2010 and 2014 after exclusion of patients with T2DM to 2006. The 2,880 control patients without T2DM from 2006 to cohort entry point were selected between 2010 and 2014 by age, sex matching with case group. The subjects without new-onset T2DM were followed until 2015. T2DM, hypertension (HTN), dyslipidemia (DYS), and end-stage renal disease (ESRD) were coded as ICD-10.

RESULTS

The frequency of new-onset T2DM in case group was significantly higher than that in control (5.6% vs. 2.2%, P<0.001). The group with T2DM (n=95) had higher incidence of CMV diseases than the group without T2DM (n=3,361) (33.7% vs. 16.2%, P<0.001). In multivariate regression model adjusted by age, sex, lower income, HTN, and DYS, the incidence rate (IR) of T2DM in case group was significantly higher than that in the control group (IR per 1,000, 19.0 vs. 7.3; odds ratio, 2.1; 95% confidence interval, 1.3 to 3.2). The co-existence of HTN, DYS, and ESRD with CMV diseases did not influence the IR of T2DM.

CONCLUSION

CMV diseases increase the patients' risk of developing T2DM.

Characterization of Baboon Cytomegalovirus Infection in Healthy Adult Baboons (Papio anubis)

Cytomegalovirus (CMV) is a common chronic herpesvirus found in humans and numerous other mammalian species. In people, chronic viruses like CMV can alter overall health and immunity and pose a serious risk for those with an inadequate immune system. In addition, CMV plays an important role in animal health, and could affect the health of vulnerable populations, like endangered species. Previous studies found a high rate of CMV seropositivity among adult baboons (Papio anubis), and results from our laboratory revealed that baboon CMV (BaCMV) seropositivity was correlated with altered immune cell populations. In the current study, we further characterized BaCMV infection in normal, adult baboons. Analysis of blood samples from baboons (age, 6 to 26 y) revealed a low overall prevalence of detectable of BaCMV DNA, with a higher detection rate in aged baboons (older than 15 y). Furthermore, data suggest that individual baboons maintain similar rates of recurrence and levels of BaCMV shedding in saliva over time. Finally, we evaluated multiple commercially available assays for antihuman CMV IgG and IgM for use with baboon sera. Results of this study will improve our understanding of BaCMV and may be directly relevant to other closely related species.

Mechanical properties of the Papio anubis tympanic membrane: Change significantly from infancy to adulthood

Mechanical properties of the tympanic membrane (TM) are important for studying the transfer function of the auditory system. However, nearly all reported human data are limited to adults because of the unavailability of temporal bones from children. In this study, we used the baboon (Papio anubis), a genetically close human relative, as a model to address the occurrence of age-dependent changes of the human TM. Forty-five baboon TMs were characterized in five age groups: <1 year, 1 to <2 years, 2 to <3 years, 3 to <5, and >5 years of age, comparable to human ages ranging from newborn to adult. The elastic properties of the baboon TMs were characterized by a micro-fringe projection technique. Volume displacement of the TM under quasi-static pressure was first determined from its micro-fringe pattern. Subsequently, these displacement values were used in a finite element model to derive mechanical properties. The Young's modulus of the baboon TM exhibited a modest decrease from 29.1 MPa to 26.0 MPa over the age groups. The average Young's modulus was ∼1.4 times higher than that of the adult human TM. This is the first time that age-related TM mechanical properties of high primate are reported. These new findings may help to explore the potential value of the baboon as a new primate model for future age-related hearing research on the normal and diseased ear.

A decline in female baboon hypothalamo-pituitary-adrenal axis activity anticipates aging

Stressors that disrupt homeostasis advance aging. Glucocorticoids regulate multiple processes that determine the aging trajectory. Debate exists regarding life-course circulating glucocorticoid concentrations. Rodent and nonhuman primate studies indicate circulating glucocorticoids fall from early life. We measured fasting morning cortisol in 24 female baboons (6-21 years, human equivalent ~18-70). We also quantified hypothalamic paraventricular nuclear (PVN) arginine vasopressin (AVP), corticotropin-releasing hormone, steroid receptors, and pituitary proopiomelanocortin immunohistochemically in 14 of these females at 6-13 years. We identified significant age-related 1) linear fall in cortisol and PVN AVP from as early as 6 years; 2) increased PVN glucocorticoid and mineralocorticoid receptors; 3) increased PVN 11β-hydroxysteroid dehydrogenase 1 and 2, regulators of local cortisol production, and 4) decreased pituitary proopiomelanocortin. Our data identify increased age-related negative feedback and local PVN cortisol production as potential mechanisms decreasing PVN drive to hypothalamo-pituitary-adrenal axis activity that result in the age-related circulating cortisol fall. Further studies are needed to determine whether the cortisol fall 1) causes aging, 2) protects by slowing aging, or 3) is an epiphenomenon unrelated to aging processes. We conclude that aging processes are best studied by linear life-course analysis beginning early in life.

CMV immune evasion and manipulation of the immune system with aging

Human cytomegalovirus (HCMV) encodes numerous proteins and microRNAs that function to evade the immune response and allow the virus to replicate and disseminate in the face of a competent innate and acquired immune system. The establishment of a latent infection by CMV, which if completely quiescent at the level of viral gene expression would represent an ultimate in immune evasion strategies, is not sufficient for lifelong persistence and dissemination of the virus. CMV needs to reactivate and replicate in a lytic cycle of infection in order to disseminate further, which occurs in the face of a fully primed secondary immune response. Without reactivation, latency itself would be redundant for the virus. It is also becoming clear that latency is not a totally quiescent state, but is characterized by limited viral gene expression. Therefore, the virus also needs immune evasion strategies during latency. An effective immune response to CMV is required or viral replication will cause morbidity and ultimately mortality in the host. There is clearly a complex balance between virus immune evasion and host immune recognition over a lifetime. This poses the important question of whether long-term evasion or manipulation of the immune response driven by CMV is detrimental to health. In this meeting report, three groups used the murine model of CMV (MCMV) to examine if the contribution of the virus to immune senescence is set by the (i) initial viral inoculum, (ii) inflation of T cell responses, (iii) or the balance between functionally distinct effector CD4+ T cells. The work of other groups studying the CMV response in humans is discussed. Their work asks whether the ability to make immune responses to new antigens is compromised by (i) age and HCMV carriage, (ii) long-term exposure to HCMV giving rise to an overall immunosuppressive environment and increased levels of latent virus, or (iii) adapted virus mutants (used as potential vaccines) that have the capacity to elicit conventional and unconventional T cell responses.