We examined the development of international adoptees from infancy to young adulthood, and factors influencing developmental outcomes in middle childhood, adolescence and young adulthood. The... Show moreWe examined the development of international adoptees from infancy to young adulthood, and factors influencing developmental outcomes in middle childhood, adolescence and young adulthood. The results for cognitive development (Chapter 2) showed that early malnutrition influenced cognitive and health-related outcomes, but its consequences did not extend to socioeconomic success later in life. The human brain seems capable of adapting to changing environmental influences, but earlier placement in a positive family environment should be preferred (see also Chapter 1). The adoptees in the Leiden Longitudinal Adoption Study were exposed to few adversities due to their early adoptive placement, and the combination with the nurturing environment of a permanent adoptive family resulted in positive cognitive and socio-emotional outcomes (Chapters 2 and 3). Our results for longitudinal (sensitivity) and concurrent relations (reactivity to infant crying) with attachment representations in young adulthood (Chapters 3 and 4) clearly point to this role of the family environment in predicting social-emotional outcomes. High parenting quality is important, also in families where children do not share a common genetic basis with their parents. In sum, adoption can be seen as a positive intervention and the (adoptive) family environment matters for children growing up from infants to young adults. Show less
Claessens, S.E.F.; Daskalakis, N.P.; Oitzl, M.S.; Kloet, E.R. de 2012
Synthetic glucocorticoids such as dexamethasone (DEX) are used to prevent or treat respiratory disorders in prematurely born infants. Besides the short-term benefit on lung development, numerous... Show moreSynthetic glucocorticoids such as dexamethasone (DEX) are used to prevent or treat respiratory disorders in prematurely born infants. Besides the short-term benefit on lung development, numerous human and animal studies have reported adverse neurodevelopmental side effects. In contrast, maternal care is known to exert a positive influence on neurodevelopmental outcome in rodents. The aim of the current study was therefore to investigate whether neonatal handling (days 1-21), known to induce maternal care, might serve as an intervention strategy modulating the adverse effects of DEX treatment (days 1-3). For this purpose we have measured the outcome of these early-life manipulations on development as well as adult endocrine and behavioral phenotype of male rats. Maternal care was observed during the first week of life and indeed enhanced in response to handling. Eye opening was accelerated and body weight reduced in DEX-treated animals. In adulthood, we report that handling ameliorated impaired spatial learning observed in DEX treated non-handled animals in the T-maze. Additionally, handling reduced susceptibility to the impact of DEX treatment in the water maze. Although DEX treatment and handling both resulted in enhanced negative feedback of the stress-induced corticosterone response and both reduced startle reactivity, the acquisition of fear was only reduced by handling, without effect of DEX. Interestingly, handling had a beneficial effect on pre-pulse inhibition, which was diminished after DEX treatment. In conclusion, these findings indicate that handling of the neonate enhances maternal care and attenuates specific DEX-induced alterations in the adult behavioral phenotype. (C) 2012 Elsevier Inc. All rights reserved. Show less
Synthetic glucocorticoids such as dexamethasone are frequently used to enhance pulmonary development in preterm ventilator-dependent infants. In contrast to the short-term benefit on survival and... Show moreSynthetic glucocorticoids such as dexamethasone are frequently used to enhance pulmonary development in preterm ventilator-dependent infants. In contrast to the short-term benefit on survival and lung maturation, early glucocorticoid exposure has been shown to adversely affect neurodevelopmental processes. Both human and animal studies have reported acute and long-lasting impairments, including shortening of the lifespan in rodents. Therefore, the objective of the studies described in this thesis was to investigate, using an animal model: 1) the short- and long-term consequences of neonatal dexamethasone treatment and 2) the possibility to prevent these effects using pharmacological and behavioural intervention strategies. We reported that systemic dexamethasone treatment acutely affects brain development by suppressing cell proliferation and glial activity. These acute effects on the brain can be partially prevented by central glucocorticoid receptor antagonist pre-treatment, which might serve as a protective strategy against the adverse effects of dexamethasone treatment on the developing brain. Although neonatal dexamethasone exposure clearly affects the developmental trajectory, we did not observe the frequently described detrimental long-lasting consequences of this treatment. We showed that daily handling of the neonate, which was an inevitable component of our experimental design and leads to enhanced levels of maternal care towards the offspring, may compensate for some of the adverse effects of dexamethasone treatment. We conclude that the impact of neonatal glucocorticoid exposure highly depends on interactions with other components of the early environment and is therefore susceptible to pharmacological and behavioural intervention strategies. Show less
