Cortisol Awakening Response in Preschoolers and Depression Risk: Relations with Maternal History of Depression and Child Temperament

Increasing research suggests that elevations in the cortisol awakening response (CAR), the natural increase of cortisol 30 to 40 minutes after waking, may serve as a vulnerability marker for depression. However, existing studies have focused on adolescence and adulthood; very little is known about the CAR in early childhood and the factors that are associated with it. The current study aimed to examine the validity of the CAR as a potential early-emerging vulnerability marker for depression in a sample of preschool-age children. We examined associations between the CAR and two well-established risk factors for depression: maternal psychopathology and early child temperament (high negative emotionality (NE) and/or low positive emotionality (PE)). The sample consisted of 146 preschool-age children, of whom 71 (49.3%) had a biological mother with a history of depression and 65 (45.5%) had a biological mother with a history of anxiety. To assess the CAR, salivary cortisol samples were collected from the child upon waking, 30 and 45 minutes post-waking on two weekdays. Children’s CAR was examined as the total volume of cortisol secreted (AUCg) and the total increase in cortisol (AUCi) across waking. Evening cortisol was collected 30 minutes before bedtime. Child temperament was assessed using observational laboratory measures. Maternal depression and anxiety were assessed with clinical interviews. Associations with children’s CAR, as indicated by AUCg or AUCi, appeared to be specific to maternal current psychopathology and symptoms of anhedonia. Additionally, we observed significant interactions for both maternal lifetime and current depression and anxiety, in combination with child NE and PE, on elevated evening cortisol levels and flattened diurnal cortisol rhythms, indicating altered patterns of basal cortisol activity in offspring. Our study contributes to the limited but growing knowledge on the development of the CAR in preschool age children and as a marker of early risk. Findings suggest that there is a complex interplay between familial risk, affective vulnerability, and their joint effects on neuroendocrine dysfunction in young children, and highlight the need for future research to examine which aspects of the early diurnal rhythm predict the emergence of later depressive illness.

Genetic manipulation of Anopheles stephensi immunity to increase plasmodium falciparum salivary gland sporozoite infection levels

Human malaria is responsible for over 700,000 deaths a year. To stay abreast of the threat posed by the parasite, a constant stream of new drugs and vector control methods are required. This study focuses on a vaccine that has the potential to protect against parasite infection, but has been hindered by developmental challenges. In malaria prevention, live, attenuated, aseptic, Plasmodium falciparum sporozoites (PfSPZ) can be administered as a highly protective vaccine. PfSPZ are produced using adult female Anopheles stephensi mosquitoes as bioreactors. Production volume and cost of a PfSPZ vaccine for malaria are expected to be directly correlated with Plasmodium falciparum infection intensity in the salivary glands. The sporogonic development of Plasmodium falciparum in A. stephensi to fully infected salivary gland stage sporozoites is dictated by the activities of several known components of the mosquito’s innate immune system. Here I report on the use of genetic technologies that have been rarely, if ever, used in Anopheles stephensi Sda500 to increase the yield of sporozoites per mosquito and enhance vaccine production. By combining the Gal4/UAS bipartite system with in vivo expression of shRNA gene silencing, activity of the IMD signaling pathway downstream effector LRIM1, an antagonist to Plasmodium development, was reduced in the midgut, fat body, and salivary glands of A. stephensi. In infection studies using P. berghei and P. falciparum these transgenic mosquitoes consistently produced significantly more salivary gland stage sporozoites than wildtype controls, with increases in P. falciparum ranging from 2.5 to 10 fold. Using Plasmodium infection assays and qRT-PCR, two novel findings were identified. First, it was shown that 14 days post Plasmodium infection, transcript abundance of the IMD immune effector genes LRIM1, TEP1 and APL1c are elevated, in the salivary glands of A. stephensi, suggesting the salivary glands may play a role in post midgut defense against the parasite. Second, a non-pathogenic IMD signaling pathway response was observed which could suggest an alternative pathway for IMD activation. The information gained from these studies has significantly increased our knowledge of Plasmodium defense in A. stephensi and moreover could significantly improve vaccine production.

Cortisol Reactivity and Observed Parenting among Mothers of Children with and without ADHD

Parenting is a robust predictor of developmental outcomes among children with ADHD. Early parenting predicts the persistence and course of ADHD and comorbid problems above and beyond risk associated with shared genetic effects. Yet, on average, mothers of children with ADHD are less positive and more negative in their parent-child interactions compared to mothers of non-disordered children. Little is known about psychobiological markers which may be associated with individual variations in maternal parenting in families of children with ADHD. Neurobiological models of parenting suggest that maternal cortisol levels following a stressor may be positively associated with hostile and intrusive parenting; however, to date no studies have examined maternal cortisol reactivity and parenting in school-age, or clinical samples of, children. Mothers’ regulation of physiological stress responses may be particularly important for families of children with ADHD, as parenting a child with chronically challenging behaviors represents a persistent environmental stressor. The current study sought to extend the existing literature by providing an empirical examination of the relationship between maternal cortisol reactivity following two laboratory stressors and parenting among mothers of children with and without ADHD. It was hypothesized that child ADHD group would moderate the relationship between cortisol reactivity and self-reported and observed parenting. Greater total cortisol output and greater increase in cortisol during the TSST were associated with decreased positive parenting and increased negative and directive parenting, with the exception of parental involvement, which was associated with increased cortisol output during the TSST. Conversely, cortisol output during the PCI was associated with increased positive parenting, increased parental involvement, and decreased negative parenting. In contrast to the TSST, a greater decrease in cortisol during the PCI indicated more positive parenting and parental involvement. These associations were specific to mothers of children with ADHD, with the exception of maternal directiveness, which was specific to comparison mothers. Findings add to our understanding of physiological processes associated with maternal parenting and contribute to an integrative biological, psychological, and cognitive process model of parenting in families of children with ADHD.

BLAZE: Bettering the lives of animals in zoo environments

Gemstone Team BLAZE