C-reactive protein (CRP) in high altitude Bolivian peri-urban adolescents varies by adiposity, current illness, height, socioeconomic status, sex, and menarcheal status: The potential benefits and costs of adipose reserves in arduous environments.

OBJECTIVES: In non-industrialized and low-income populations, adipose stores can serve as a valuable buffer against harsh conditions such as seasonal food scarcity. However, these reserves may incur costs due to adipocytes' production of pro-inflammatory cytokines; inflammation is associated with increased risk for cardiometabolic diseases later in life. Life history theory posits that, especially in populations with high juvenile mortality, higher adiposity may nonetheless be advantageous if its benefits in early life outweigh its later costs. Relatively little is known about adolescents' C-reactive protein concentration (CRP; an inflammation biomarker) in such environments. We investigated CRP and its associations with several hypothesized predictors in adolescents in an economically diverse peri-urban Andean community. METHODS: We measured CRP in dried blood spots and collected data on anthropometrics, illnesses, socioeconomic status (SES), and menarcheal status in 59 female and 40 male adolescents ("Alteños", 11.0-14.9 years old) with normal vital signs in El Alto, Bolivia (~4150 m amsl). We used Cole's LMS method to standardize all anthropometrics for sex and age, and principal components analysis to construct a "fat-factor" variable loading on these standardized z-scores. We used multiple linear regression to assess the influence of fat-factor and other likely predictors on CRP rank. RESULTS: Compared to a national Bolivian growth reference, Alteños were, on average, shorter and leaner; only 6% were classified as overweight and none were obese. Pre-menarche females were on average leaner than post-menarche females. The best-fitting model explained 24% of the variance in CRP rank. Significant predictors were fat-factor, SES, current illness for males and pre-menarche females, and z-height for females. CONCLUSIONS: Our results are consistent with a tradeoff between investments in growth versus immune functioning, as might be expected in an environment with limited resources and high pathogen exposure (e.g., soil-transmitted helminths, poor sanitation). Thinner Alteños appear to maintain a minimum CRP concentration independent of fat-factor, while fatter (or less-thin) Alteños' CRP rises with fat-factor. Female Alteños appear to be trading off investment in immune response for investment in growth and maturation. Alteños' high rate of stunting and absence of obesity suggests chronic, presumably multifactorial, stress. Adipose stores likely buffer against some of these stressors and, in an environment such as this-in which many lack sufficient nutritious foods, potable water, adequate sewage, and health care-may confer a net lifetime benefit.

OBJETIVOS: En poblaciones no industrializadas y de bajos ingresos, las reservas adiposas pueden servir como un valioso amortiguador frente a condiciones duras como la escasez estacional de alimentos. Sin embargo, estas reservas pueden tener un coste debido a la producción de citoquinas proinflamatorias por parte de los adipocitos; la inflamación se asocia a un mayor riesgo de enfermedades cardiometabólicas en etapas posteriores de la vida. La teoría de la historia vital postula que, especialmente en poblaciones con una elevada mortalidad juvenil, una mayor adiposidad puede ser ventajosa si sus beneficios en los primeros años de vida compensan sus costes posteriores. Se sabe relativamente poco sobre la concentración de proteína C reactiva (PCR; un biomarcador de inflamación) de los adolescentes. Investigamos la PCR y sus asociaciones con varios predictores hipotéticos en adolescentes de una comunidad andina periurbana económicamente diversa. MÉTODOS: Se midió la PCR en muestras de sangre seca y se recogieron datos sobre antropometría, enfermedades, nivel socioeconómico (NSE) y menarquia en 59 mujeres y 40 varones adolescentes («alteños¼, 11,0­14,9 años de edad) con signos vitales normales en El Alto, Bolivia (~4150m amsl). Usamos el método LMS de Cole para estandarizar todos los parámetros antropométricos para sexo y edad, y análisis de componentes principales para construir una variable «factor de grasa¼ cargada en estos puntajes z­estandarizados. Se utilizó la regresión lineal múltiple para evaluar la influencia del factor grasa y otros posibles predictores en el rango de la PCR. RESULTADOS: En comparación con una referencia nacional boliviana de crecimiento, los alteños eran, en promedio, más bajos y más delgados; sólo el 6% estaban clasificados con sobrepeso y ninguno era obeso. Las chicas premenárquicos eran, en promedio, más delgados que las chicas postmenárquicos. El modelo de regresión que mejor se ajustaba explicaba el 24% de la varianza en el rango de PCR. Observamos una nueva asociación entre la adiposidad y la PCR. Cuando el factor adiposidad es >0, el rango de la PCR aumenta linealmente con el factor adiposidad. Cuando el factor adiposidad es <0, la PCR no varía con el factor adiposidad. Estos patrones sugieren que los Alteños más delgados mantienen una concentración mínima de PCR independiente del factor adiposidad, mientras que la PCR de los Alteños más gordos (menos delgados) aumenta con el factor adiposidad. Además, existe una mayor variación en el rango de la PCR en los adolescentes más delgados que en los más gordos. El autoinforme de una enfermedad actual en niños y niñas premenárquicas se asoció con una PCR significativamente más alta. La ausencia de una asociación significativa entre la enfermedad actual y la PCR en las chicas postmenárquicas puede reflejar confusión por cambios en la PCR durante el ciclo menstrual. Manteniendo constantes todos los demás factores predictivos, la PCR aumentó con el incremento del nivel socioeconómico. En las niñas, el aumento de la estatura se asoció a una disminución de la PCR, lo que sugiere que las niñas favorecen la inversión en crecimiento y maduración frente a la inversión en respuestas inmunitarias inflamatorias a corto plazo. En los chicos, no se observó una relación significativa entre la estatura y la PCR. La baja estatura y la delgadez de estos adolescentes sugieren que pueden estar invirtiendo en defensas humorales a más largo plazo (por ejemplo, anticuerpos contra helmintos), pero esta hipótesis requiere más estudios. CONCLUSIONES: La alta tasa de retraso en el crecimiento y la ausencia de obesidad de los alteños sugieren un estrés crónico, presumiblemente multifactorial. Muchas familias carecen de alimentos nutritivos suficientes, agua potable, alcantarillado adecuado y atención sanitaria. Es probable que las reservas adiposas amortigüen algunos de estos factores de estrés y confieran un beneficio neto a lo largo de la vida (la reducción de la mortalidad juvenil puede compensar cualquier aumento del riesgo de enfermedades cardiometabólicas en etapas posteriores de la vida). Sin embargo, estas compensaciones tienen un coste para los individuos y las sociedades. Reducir los riesgos de patógenos y mejorar la capacidad de los habitantes del altiplano para acceder sistemáticamente a agua limpia y a alimentos sanos suficientes y asequibles probablemente reportaría beneficios para la salud a lo largo de toda la vida.

Well-being in healthy Icelandic women varies with extreme seasonality in ambient light.

Seasonal variation in photoperiod may affect psychosocial and physical well-being in healthy persons. We tested this hypothesis in healthy pre-menopausal women, without a history of mood disorders, living year-round in Reykjavik, Iceland (64.1°N). Participants reported daily self-assessments of well-being throughout a complete ovulatory menstrual cycle in summer and/or winter (70% participated in both seasons). Scores for mood, cognitive acuity, social support, physical health and a composite of these four indicators were each significantly higher in summer than in winter (linear mixed effects models: p < .001 for each model); tiredness did not differ by season. The effect of season was not significantly changed by inclusion of body mass index and/or age as covariates. Some prior studies have been hampered by sparse time sampling, inattention to covariates and/or relying on recalled data. This is to our knowledge the first investigation to test the study hypothesis with daily real-time data spanning complete ovulatory menstrual cycles in each of two seasons. This dense sampling has revealed modest seasonal variation in well-being in healthy women. Daylength (sunlight exposure) is likely a major, but not necessarily sole, factor in these seasonal differences in well-being; temperature is likely less important given Iceland's relatively moderate (for its high latitude) seasonal temperature swings.

Socioeconomic impacts on Andean adolescents' growth: Variation between households, between communities and over time.

Background/Objectives: We evaluated potential socioeconomic contributors to variation in Andean adolescents' growth between households within a peri-urban community undergoing rapid demographic and economic change, between different community types (rural, peri-urban, urban) and over time. Because growth monitoring is widely used for assessing community needs and progress, we compared the prevalences of stunting, underweight, and overweight estimated by three different growth references. Methods: Anthropometrics of 101 El Alto, Bolivia, adolescents (Alteños), 11.0-14.9 years old in 2003, were compared between households (economic status assessed by parental occupations); to one urban and two rural samples collected in 1983/1998/1977, respectively; and to the WHO growth reference, a representative sample of Bolivian children (MESA), and a region-wide sample of high-altitude Peruvian children (Puno). Results: Female Alteños' growth was positively associated with household and maternal income indices. Alteños' height averaged ∼0.8SD/∼0.6SD/∼2SDs greater than adolescents' height in urban and rural communities measured in 1983/1998/1977, respectively. Overweight prevalence was comparable to the WHO, and lower than MESA and Puno, references. Stunting was 8.5/2.5/0.5 times WHO/MESA/Puno samples, respectively. Conclusions/Implications: Both peri-urban conditions and temporal trends contributed to gains in Alteños' growth. Rural out-migration can alleviate migrants' poverty, partly because of more diverse economic options in urbanized communities, especially for women. Nonetheless, Alteños averaged below WHO and MESA height and weight medians. Evolved biological adaptations to environmental challenges, and the consequent variability in growth trajectories, favor using multiple growth references. Growth monitoring should be informed by community- and household-level studies to detect and understand local factors causing or alleviating health disparities.

Using an on-site laboratory for fecal steroid analysis in wild white-faced capuchins.

Hormone laboratories located "on-site" where field studies are being conducted have a number of advantages. On-site laboratories allow hormone analyses to proceed in near-real-time, minimize logistics of sample permits/shipping, contribute to in-country capacity-building, and (our focus here) facilitate cross-site collaboration through shared methods and a shared laboratory. Here we provide proof-of-concept that an on-site hormone laboratory (the Taboga Field Laboratory, located in the Taboga Forest Reserve, Costa Rica) can successfully run endocrine analyses in a remote location. Using fecal samples from wild white-faced capuchins (Cebus imitator) from three Costa Rican forests, we validate the extraction and analysis of four steroid hormones (glucocorticoids, testosterone, estradiol, progesterone) across six assays (DetectX® and ISWE, all from Arbor Assays). Additionally, as the first collaboration across three long-term, wild capuchin field sites (Lomas Barbudal, Santa Rosa, Taboga) involving local Costa Rican collaborators, this laboratory can serve as a future hub for collaborative exchange.

Screening for Phytoestrogens using a Cell-based Estrogen Receptor ß Reporter Assay.

Plants are a source of food for many animals, and they can produce thousands of chemicals. Some of these compounds affect physiological processes in the vertebrates that consume them, such as endocrine function. Phytoestrogens, the most well studied endocrine-active phytochemicals, directly interact with the hypothalamo-pituitary gonadal axis of the vertebrate endocrine system. Here we present the novel use of a cell-based assay to screen plant extracts for the presence of compounds that have estrogenic biological activity. This assay uses mammalian cells engineered to highly express estrogen receptor beta (ERß) and that have been transfected with a luciferase gene. Exposure to compounds with estrogenic activity results in the cells producing light. This assay is a reliable and simple way to test for biological estrogenic activity. It has several improvements over transient transfection assays, most notably, ease of use, the stability of the cells, and the sensitivity of the assay.

Vaginal Glycogen, Not Estradiol, Is Associated With Vaginal Bacterial Community Composition in Black Adolescent Women.

PURPOSE: The purpose of this study was to characterize the composition of vaginal bacterial communities in a cohort of black adolescent women and to determine how the species composition of these communities correlates with levels of estradiol, glycogen, and stress. METHODS: Twenty-one black adolescent women were sampled longitudinally. The composition of their vaginal communities was determined by analyzing the sequences of the V1-V3 regions of 16S rRNA genes, and they were grouped based on patterns in species abundances. The relationships between estradiol, glycogen, psychosocial stress, and the composition of these communities were assessed. RESULTS: Vaginal communities could be distinguished and classified into three groups that differed in the abundances of Lactobacillus. Eighty-one percent of study participants had communities dominated by species of Lactobacillus. Glycogen levels were higher in communities dominated by one or multiple species of Lactobacillus compared with those having low proportions of Lactobacillus. Estradiol and psychosocial stress measurements did not differ among the three groups, whereas estradiol and glycogen exhibited a weak positive relationship that was not statistically significant. CONCLUSIONS: The findings of this pilot study suggest that glycogen levels are associated with vaginal community composition in young black women; however, estradiol and psychosocial stress are not. In addition, the results suggest there is no simple relationship between levels of estradiol and the production of vaginal glycogen.

Timing of Maternal Immunization Affects Immunological and Behavioral Outcomes of Adult Offspring in Siberian Hamsters (Phodopus sungorus).

Maternal influences are an important contributing factor to offspring survival, development, and behavior. Common environmental pathogens can induce maternal immune responses and affect subsequent development of offspring. There are likely sensitive periods during pregnancy when animals are particularly vulnerable to environmental disruption. Here we characterize the effects of maternal immunization across pregnancy and postpartum on offspring physiology and behavior in Siberian hamsters (Phodopus sungorus). Hamsters were injected with the antigen keyhole limpet hemocyanin (KLH) (1) prior to pairing with a male (premating), (2) at separation (postmating), (3) at midpregnancy, or (4) after birth (lactation). Maternal food intake, body mass, and immunity were monitored throughout gestation, and litters were measured weekly for growth until adulthood when social behavior, hormone concentrations, and immune responses were determined. We found that immunizations altered maternal immunity throughout pregnancy and lactation. The effects of maternal treatment differed between male and female offspring. Aggressive behavior was enhanced in offspring of both sexes born to mothers treated postmating and thus early in pregnancy relative to other stages. In contrast, maternal treatment and maternal stage differentially affected innate immunity in males and females. Offspring cortisol, however, was unaffected by maternal treatment. Collectively, these data demonstrate that maternal immunization affects offspring physiology and behavior in a time-dependent and sex-specific manner. More broadly, these findings contribute to our understanding of the effects of maternal immune activation, whether it be from environmental exposure or immunization, on immunological and behavioral responses of offspring.

Maternal immune activation affects litter success, size and neuroendocrine responses related to behavior in adult offspring.

It is increasingly evident that influences other than genetics can contribute to offspring phenotype. In particular, maternal influences are an important contributing factor to offspring survival, development, physiology and behavior. Common environmental pathogens such as viral or bacterial microorganisms can induce maternal immune responses, which have the potential to alter the prenatal environment via multiple independent pathways. The effects of maternal immune activation on endocrine responses and behavior are less well studied and provide the basis for the current study. Our approach in the current study was two-pronged: 1) quantify sickness responses during pregnancy in adult female hamsters experiencing varying severity of immune responsiveness (i.e., differing doses of lipopolysaccharide [LPS]), and 2) assess the effects of maternal immune activation on offspring development, immunocompetence, hormone profiles, and social behavior during adulthood. Pregnancy success decreased with increasing doses of LPS, and litter size was reduced in LPS dams that managed to successfully reproduce. Unexpectedly, pregnant females treated with LPS showed a hypothermic response in addition to the more typical anorexic and body mass changes associated with sickness. Significant endocrine changes related to behavior were observed in the offspring of LPS-treated dams; these effects were apparent in adulthood. Specifically, offspring from LPS treated dams showed significantly greater cortisol responses to stressful resident-intruder encounters compared with offspring from control dams. Post-behavior cortisol was elevated in male LPS offspring relative to the offspring of control dams, and was positively correlated with the frequency of bites during agonistic interactions, and cortisol levels in both sexes were related to defensive behaviors, suggesting that changes in hypothalamo-pituitary-adrenal axis responsiveness may play a regulatory role in the observed behavioral differences. Overall, the results of this study provide evidence that maternal immune activation can exert marked effects on offspring physiology and behavior.

Stress-evoked increases in serotonin in the auditory midbrain do not directly result from elevations in serum corticosterone.

Neurochemicals such as serotonin convey information about behavioral context to sensory processing. In the auditory system, serotonin modulates the responses of neurons in the inferior colliculus (IC) to acoustic stimuli, including communication vocalizations. Levels of extracellular serotonin in the IC can change rapidly in response to stressful situations such as social challenge and limited movement. Since activation of the hypothalamo-pituitary-adrenal (HPA) axis can influence serotonin in other brain regions, we examined the relationship between serum corticosterone and serotonin release in the IC. We used voltammetry to measure extracellular serotonin in the IC of male CBA/J mice during restriction of movement, a low-intensity restraint stress. Enzyme immunoassay (EIA) was used to measure the concentration of corticosterone circulating in the blood serum as an indicator of the activation of the HPA axis. Changes in serotonin and corticosterone were also compared with behavioral performance. Restriction stress caused increases in serotonin in the IC and circulating corticosterone, and changes in behavior. Changes in serotonin and corticosterone were not correlated with each other across individuals. Individual behavioral performance was correlated with elevations in corticosterone, but not in serotonin. We further explored the relationship between physiological pathways by directly manipulating serum corticosterone. Injections of corticosterone elevated circulating levels beyond normal physiological ranges, but had no effect on serotonin in the IC. These findings suggest that, within the auditory system, serotonin is released during stressful events, but this is a correlate of behavioral arousal, rather than a direct response to elevations in serum corticosterone.

Social defeat differentially affects immune responses in Siberian hamsters (Phodopus sungorus).

Social defeat is a complex, multi-faceted behavioral interaction capable of eliciting a wide range of physiological and behavioral responses. The behavioral components responsible for eliciting these changes, however, remain unspecified. The goal of the present study was to examine the effects of chronic social defeat on serum cortisol concentration as well as innate and acquired immune responses in adult male Siberian hamsters (Phodopus sungorus). Specifically, we experimentally manipulated the nature of the social interaction among conspecific animals (i.e., no social interaction, exposure to the sight or smell of a conspecific, or full social defeat) in order to determine the important components contributing to potential stress-induced changes in immunity. We found that immunoglobulin G (IgG) levels were decreased in defeated animals relative to both control animals and those exposed only to the olfactory cues of conspecifics. In contrast, serum bactericidal activity was increased in the defeated animals relative to controls. Prolonged social defeat did not elevate serum cortisol levels as compared with control animals. The results of this study suggest that social defeat alters immune responses and that specific behavioral components (i.e., defeat) contribute to this response. Importantly, these findings also demonstrate that social defeat exerts opposite effects on innate and acquired measures of immunity. Collectively, these results contribute to our understanding of complex social behaviors and their differential effects on endocrine and immune responses in vertebrates.

Exogenous insulin enhances humoural immune responses in short-day, but not long-day, Siberian hamsters (Phodopus sungorus).

Many animals experience marked seasonal fluctuations in environmental conditions. In response, animals display adaptive alterations in physiology and behaviour, including seasonal changes in immune function. During winter, animals must reallocate finite energy stores from relatively costly, less exigent systems (e.g. reproduction and immunity) to systems critical for immediate survival (e.g. thermoregulation). Seasonal changes in immunity are probably mediated by neuroendocrine factors signalling current energetic state. One potential hormonal candidate is insulin, a metabolic hormone released in response to elevated blood glucose levels. The aim of the present study was to explore the potential role of insulin in signalling energy status to the immune system in a seasonally breeding animal, the Siberian hamster (Phodopus sungorus). Specifically, exogenous insulin was administered to male hamsters housed in either long 'summer-like' or short 'winter-like' days. Animals were then challenged with an innocuous antigen and immune responses were measured. Insulin treatment significantly enhanced humoural immune responses in short, but not long days. In addition, insulin treatment increased food intake and decreased blood glucose levels across photoperiodic treatments. Collectively, these data support the hypothesis that insulin acts as an endocrine signal integrating seasonal energetic changes and immune responses in seasonally breeding rodents.

Leptin increases maternal investment.

The primary goal of virtually all organisms is to produce genetic offspring, thereby passing on their genes to future generations. Offspring production, however, is limited by available resources within an environment. Moreover, distributing sufficient energy among competing physiological systems is challenging and can result in trade-offs between self-maintenance and offspring investment when resources are limited. In the current study, we tested the hypothesis that the adipose hormone leptin is involved in mediating energetic trade-offs between competing physiological systems. Specifically, we tested the effects of elevated maternal leptin on investment into offspring production versus self maintenance (immune function), in the Siberian hamster (Phodopus sungorus). The current study provides the first evidence that leptin serves as a signal to mothers of available energy resulting in epigenetic effects. Therefore, elevated leptin allows females to retain more embryos to parturition, and rear more offspring to weaning via reduced maternal infanticide. Innate immune response was suppressed seemingly as a result of these enlarged litters, suggesting that the observed fitness increase is not without costs to the mother. Collectively, these findings suggest that leptin plays a critical role in allowing mothers to determine how much energy to invest in the production and care of young versus self-maintenance.