Early life stress is associated with anxiety, increased stress responsivity and preference for "comfort foods" in adult female rats.

Chronic stress increases anxiety and encourages intake of palatable foods as "comfort foods". This effect seems to be mediated by altered function of the hypothalamic-pituitary-adrenal axis. In the current study, litters of Wistar rats were subjected to limited access to nesting material (Early-Life Stress group - ELS) or standard care (Control group) from postnatal day 2 to 9. In adult life, anxiety was assessed using the novelty-suppressed feeding test (NSFT), and acute stress responsivity by measurement of plasma corticosterone and ACTH levels. Preference for palatable foods was monitored by a computerized system (BioDAQ, Research Diets(®)) in rats receiving only regular chow or given the choice of regular and palatable diet for 30 days. ELS-augmented adulthood anxiety in the NSFT (increased latency to eat in a new environment; decreased chow intake upon return to the home cage) and increased corticosterone (but not ACTH) secretion in response to stress. Despite being lighter and consuming less rat chow, ELS animals ate more palatable foods during chronic exposure compared with controls. During preference testing, controls receiving long-term access to palatable diet exhibited reduced preference for the diet relative to controls exposed to regular chow only, whereas ELS rats demonstrated no such reduction in preference after prolonged palatable diet exposure. The increased preference for palatable foods showed by ELS animals may result from a habit of using this type of food to ameliorate anxiety.

Association between Na⁺,K⁺-ATPase activity and the vulnerability/resilience to mood disorders induced by early life experience.

There is increasing evidence that early life events can influence neurodevelopment and later susceptibility to disease. Chronic variable stress (CVS) has been used as a model of depression. The objective of this study was to evaluate the interaction between early experience and vulnerability to chronic variable stress in adulthood, analyzing emotional, metabolic and neurochemical aspects related to depression. Pups were (1) handled (10 min/day) or (2) left undisturbed from day 1 to 10 after birth. When the animals reached adulthood, the groups were subdivided and the rats were submitted or not to CVS, which consisted of daily exposure to different stressors for 40 days, followed by a period of behavioral tasks, biochemical (plasma corticosterone and insulin sensitivity) and neurochemical (Na⁺,K⁺-ATPase activity in hippocampus, amygdala and parietal cortex) measurements. Neonatally-handled rats demonstrated shorter immobility times in the forced swimming test, independently of the stress condition. There was no difference concerning basal corticosterone or insulin sensitivity between the groups. Na⁺,K⁺-ATPase activity was decreased in hippocampus and increased in the amygdala of neonatally-handled rats. CVS decreased the enzyme activity in the three structures, mainly in the non-handled group. These findings suggest that early handling increases the ability to cope with chronic variable stress in adulthood, with animals showing less susceptibility to neurochemical features associated with depression, confirming the relevance of the precocious environment to vulnerability to psychiatric conditions in adulthood.

Variations in the neonatal environment modulate adult behavioral and brain responses to palatable food withdrawal in adult female rats.

BACKGROUND/OBJECTIVES: Early handling alters adult behavioral responses to palatable food and to its withdrawal following a period of chronic exposure. However, the central mechanisms involved in this phenomenon are not known. Since neonatal handling has persistent effects on stress and anxiety responses, we hypothesized that its involvement in the aforementioned association may be associated with differential neuroadaptations in the amygdala during withdrawal periods. METHODS: Litters were randomized into two groups: handled (H, removed from their dam for 10min per day from the first to the tenth postnatal day and placed in an incubator at 32°C) and non-handled (NH). Experiment 1: on PNDs 80-100, females were assigned to receive palatable food+rat chow for 15 or 30 days, and these two groups were compared in terms of palatable food preference, body weight and abdominal fat deposition. In Experiment 2, H and NH rats were exposed to a chronic diet of palatable food+rat chow for 15 days, followed by (a) no withdrawal, (b) 24h withdrawal from palatable food (receiving only rat chow) or (c) 7-day withdrawal from palatable food (receiving only rat chow). Body weight, 10-min rebound palatable food intake, abdominal fat deposition, serum corticosterone as well as TH and pCREB levels in the amygdala were then compared between groups. RESULTS: Experiment 1-chronic exposure to palatable food induces comparable metabolic effects after 15 and 30 days. Experiment 2-neonatal handling is associated with a peculiar response to palatable food withdrawal following chronic exposure for 15 days. Rats exposed to early handling ingested less of this food after a 24h withdrawal period, and displayed increased amygdala TH and pCREB levels. CONCLUSIONS: Variations in the neonatal environment affect both behavioral responses and amygdala neuroadaptation to acute withdrawal from a palatable diet. These findings contribute to the comprehension of the mechanisms that link early life events and altered feeding behavior and related morbidities such as obesity in adulthood.

Both food restriction and high-fat diet during gestation induce low birth weight and altered physical activity in adult rat offspring: the "Similarities in the Inequalities" model.

We have previously described a theoretical model in humans, called "Similarities in the Inequalities", in which extremely unequal social backgrounds coexist in a complex scenario promoting similar health outcomes in adulthood. Based on the potential applicability of and to further explore the "similarities in the inequalities" phenomenon, this study used a rat model to investigate the effect of different nutritional backgrounds during gestation on the willingness of offspring to engage in physical activity in adulthood. Sprague-Dawley rats were time mated and randomly allocated to one of three dietary groups: Control (Adlib), receiving standard laboratory chow ad libitum; 50% food restricted (FR), receiving 50% of the ad libitum-fed dam's habitual intake; or high-fat diet (HF), receiving a diet containing 23% fat. The diets were provided from day 10 of pregnancy until weaning. Within 24 hours of birth, pups were cross-fostered to other dams, forming the following groups: Adlib_Adlib, FR_Adlib, and HF_Adlib. Maternal chow consumption and weight gain, and offspring birth weight, growth, physical activity (one week of free exercise in running wheels), abdominal adiposity and biochemical data were evaluated. Western blot was performed to assess D2 receptors in the dorsal striatum. The "similarities in the inequalities" effect was observed on birth weight (both FR and HF groups were smaller than the Adlib group at birth) and physical activity (both FR_Adlib and HF_Adlib groups were different from the Adlib_Adlib group, with less active males and more active females). Our findings contribute to the view that health inequalities in fetal life may program the health outcomes manifested in offspring adult life (such as altered physical activity and metabolic parameters), probably through different biological mechanisms.

Considerações sobre aprendizagem baseada em problemas na educação em saúde / Considerations about problem-based learning in the process of health education

A aprendizagem baseada em problemas (Problem-Based Learning – PBL) tem sido reconhecida mundialmente como uma abordagem capaz de promover a aquisição de conhecimentos pelos alunos ao mesmo tempo em que os ajuda a desenvolver habilidades e atitudes profissionais desejáveis. Diferentemente dos métodos convencionais de ensino, que utilizam problemas de aplicação após a apresentação da teoria, o PBL utiliza um problema para iniciar, enfocar e motivar a aprendizagem de novos conceitos. Nessa abordagem, o aluno utiliza diferentes processos mentais, como capacidade de levantar hipóteses, comparar, analisar, interpretar e avaliar, desenvolvendo a habilidade de assumir responsabilidade por sua formação. A metodologia PBL tem se mostrado um instrumento valioso na formação do profissional de saúde, com vantagens sobre o método de ensino tradicional. No entanto, para a sua implantação, há necessidade de um considerável esforço institucional. São necessárias adaptações, tais como mudanças na forma de avaliação, mudanças na forma de ver o papel do docente no processo ensino/aprendizagem, investimentos em infraestrutura, adaptações do ambiente, melhoria das bibliotecas, entre outros. O processo de mudança da educação traz inúmeros desafios como, por exemplo, romper com modelos de ensino tradicional e formar profissionais de saúde com competências que lhes permitam recuperar a dimensão essencial do cuidado: a relação entre humanos.

Problem-Based Learning (PBL) has been recognized worldwide as an approach that promotes the acquisition of knowledge by students at the same time that it helps them develop desirable skills and professional attitudes. Unlike the conventional teaching methods, which use problem-solving after the theory has been presented, PBL uses a problem to start, focus and motivate the learning of new concepts. According to this approach, students use different mental processes, such as ability to suggest hypotheses, compare, analyze, interpret, and evaluate, to develop the ability to take responsibility for their education. PBL methodology has been a valuable tool in the education of health professionals, with advantages over the traditional teaching method. However, in order to implement such methodology, considerable institutional effort is necessary. Adjustments must be made, including changes in the methods of evaluation, changes in mind-set on the role of teachers in the teaching/learning process, investments in infrastructure, adaptations of the environment, improvement of libraries, among others. The process of change in education brings many challenges, such as breaking with traditional models of education and training health professionals so that they acquire skills to recover the essential dimension of care: the relationship between people.