Different sleep patterns during the COVID-19 pandemic: association with mood, exercise and light exposure.

The aim was to evaluate the sleep-wake cycle pattern, mood, perceived stress and some behaviors, such as physical exercise and exposure to natural light of college students during the COVID-19 pandemic. This is a cross-sectional study conducted between June and August 2020 using an electronic form provided by Google. The sample consisted of undergraduate students aged between 18 and 30 years old and residents of the northeast region of Brazil. The students generally had sleepiness and poor sleep quality, high levels of anxiety, mild to moderate depressive symptoms and moderate perceived stress. Some of these aspects were worse in women. The college students showed three sleep patterns: one group had good sleep quality without excessive daytime sleepiness; another group had poor sleep quality, but no excessive daytime sleepiness; and a third group had high daytime sleepiness, and less expressive sleep quality impairment. Greater exposure to sunlight and practicing physical exercise predominated in individuals with better sleep quality, suggesting that they are protective factors. In addition, excessive daytime sleepiness and poor sleep quality were separately associated with higher anxiety, depression and stress perception levels, proving to be important aspects for care in order to favor mental health during the pandemic. In conclusion, it is suggested that the COVID-19 pandemic affected the sleep of college students in a heterogeneous way. The differentiated sleep patterns are associated with exposure to natural light and exercising.

Perinatal and post-weaning exposure to an obesogenic diet promotes greater expression of nuclear factor-κB and tumor necrosis factor-α in white adipose tissue and hypothalamus of adult rats.

Aim: To analyze the effects of exposure to a high-fat diet during the perinatal period and after weaning on white adipose tissue accumulation and gene expression of TNF- α and NF- κB.Method: Wistar female rats were fed with high-fat (H) or control (C) diet during pregnancy and lactation. The offspring were allocated into four groups: Control Control (CC), offspring of mothers GC, fed a control diet after weaning; Control High-fat (CH), offspring of mothers GC, fed a hight-fat diet after weaning; High-fat Control (HC), offspring of mothers GH, fed with control diet after weaning; and High-fat High-fat (HH), offspring of mothers GH, fed a H diet after weaning.Results: HH and HC groups showed increased body weight compared to CC group and increases in caloric intake, larger amount of white adipose tissue and adipocyte size compared to CC and CH groups. The HH and CH groups showed higher NF-kB expression in white adipose tissue compared to the CC and HC groups, and the HH group also showed higher TNF- α expression. In the hypothalamus, the HH and HC groups exhibited higher TNF- α expression compared to the CC and CH groups.Conclusion: Perinatal and post-weaning exposure to the high-fat diet increases the amount of white adipose tissue, adipocyte size, and expression of the inflammatory genes TNF-α and NF-kB.

Early life stress induced by maternal separation during lactation alters the eating behavior and serotonin system in middle-aged rat female offspring.

Stressful events occurring during early life have been related to behavioral and neurochemical disturbances. Maternal separation during the first two weeks of life is a traumatic event that strongly affects the feeding behavior and serotonergic system of the progeny in adulthood. As this system modulates the feeding behavior, the present study aimed at investigating the effects of maternal separation-induced stress on both the feeding behavior and serotonergic system of the middle-aged female rats by manipulating this system using fluoxetine, a selective serotonin transporter inhibitor. Lactating Wistar rats were separated from their litters from postnatal day 2 (PND 2) to PND 14 for 3 h in the dark phase of the circadian cycle. The maternally separated (MS) and control (C) groups were distinguished from each other based on the incidence or absence of maternal separation (early life stress). All the analyses were done on the female offspring from one-year of age. Maternal separation anticipated the satiety point in these females. This anticipation was linked to lower food intake, meal duration and meal size. These results mirrored the effects of fluoxetine in the control animals. Furthermore, maternal separation was associated with 5ht1b serotonin receptor hyperexpression in the hypothalamus. These findings demonstrate that maternal separation has long-lasting effects on the eating behavior and serotonergic system and that this system could be responsible for mediating these behavioral outcomes.

Low omega-6/omega-3 ratio in a maternal protein-deficient diet promotes histone-3 changes in progeny neural cells and favors leukemia inhibitory factor genetranscription.

Omega-3 (n-3) fatty acids modulate epigenetic changes critical to genesis and differentiation of neural cells. Conversely, maternal protein-malnutrition can negatively modify these changes. This study investigated whether a low n-6/n-3 ratio in a maternal diet could favor histone-3 (H3) modifications, gene transcription and differentiation in the offspring neural cells even under protein-deficiency. Female rats fed a control (Ct), or 3 types of multideficient diets differing in protein levels or linoleic/alpha-linolenic fatty acid ratios (RBD, RBD-C, RBD-SO) from 30 days prior to mating and during pregnancy. Cerebral cortex tissue and cortical cultures of progeny embryonic neurons and postnatal astrocytes were analyzed. H3K9 acetylation and H3K27 or H3K4 di-methylation levels were assessed by flow cytometry and/or immunocytochemistry. In astrocyte cultures and cortical tissue, the GFAP protein levels were assessed. Glial derived neurotrophic factor (GDNF) and leukemia inhibitory factor (LIF) gene expression were evaluated in the cortical tissue. GFAP levels were similar in astrocytes of Ct, RBD and RBD-C, but 65% lower in RBD-SO group. Higher levels of H3K9Ac were found in the neurons and H3K4Me2 in the astrocytes of the RBD group. No intergroup difference in the cortical GDNF mRNA expression or the H3K27Me2 levels in astrocytes was detected. LIF mRNA levels were higher in the RDB (P=.002) or RBD-C (P=.004) groups than in the control. The findings indicate the importance of dietary n-3 availability for the brain, even under a protein-deficient condition, inducing Histone modifications and increasing LIF gene transcription, involved in neural cell differentiation and reactivity.

Pre-weaning maternal separation increases eating later in life in male and female offspring, but increases brainstem dopamine receptor 1a and 2a only in males.

Maternal separation stress (MS) is a model of early life stress performed by the separation between dam and pups in the first days of life. This model has been associated with eating behavior and dopaminergic system abnormal phenotypes. This study aims to investigate whether maternal separation in the light or dark phase of the circadian cycle promotes phenotypic adjustments in the eating behavior and the dopamine system in both males and females. Lactating Wistar rats were separated from their litters from postnatal day 1 (PND 1) to PND 14 for 6 h in the light or dark phase of the circadian cycle. The groups of female control (FC), male control (MC), female rat separated in the dark (FSD), male rat separated in the dark (MSD), female rat separated in the light (FSL), and male rat separated in the light (MSL) were composed. The assessment of food intake was performed at the age of 120-150 days and the analysis of brainstem drd1a and drd2a dopamine receptors expression at 180 days of life. Maternal separation promoted higher palatable diet intake independent on sex and circadian cycle. On the other hand, drd1a and drd2a dopamine receptors expression were higher only in males separated in the dark phase of the circadian cycle. These findings demonstrate that maternal separation effects on feeding behavior do not depend on sex and circadian cycle, but the effects on dopamine receptors expression depend on sex and circadian cycle.

Daytime increase in caloric intake without change in total 24-h caloric intake can increase adiposity but not total bodyweight in rats with inverted feeding pattern.

The goal of this study was to evaluate the effect of the food availability period on body weight, self-selection of macronutrients, adiposity, lipoprotein, and serum glucose profiles without changing energy intake. Young male rats were divided into 2 groups according to the availability of food during the light and dark phases of the cycle, forming 2 groups: control group (CG) and group with inverted feeding pattern (IFPG). Before inversion of food availability on the 80th day, circadian food intake was measured every 4 h over 24 h during 3 days. The glycemic curve, an oral test for glucose tolerance, and self-selection of macronutrients were evaluated. Blood samples were collected for analysis of fasting glucose, triglycerides, and total cholesterol fractions. The IFPG showed an increase in fasting glucose in the dark phase of the cycle, changes in the glycemic curve, and oral glucose tolerance test. It also showed increased abdominal and liver fat and distinct choice of macronutrients compared with the CG. A change in the availability of food according to the phase of the circadian cycle produces changes in glucose and feeding circadian rhythm culminating in increased abdominal and hepatic fat. These effects can increase the risk of metabolic disorders and installation of chronic diseases.

Neonatal serotonin reuptake inhibition reduces hypercaloric diet effects on fat mass and hypothalamic gene expression in adult rats.

BACKGROUND: Serotonin (5-HT) is involved in nervous system ontogenesis, and is important for neurotransmission and behavior modulation after the developmental stage. Alterations in 5-HT levels during the early period of life may signal to feeding behavior and hypothalamic genic expression changes in adulthood. OBJECTIVES: Investigate the effects of hypercaloric diet in adult rats submitted to neonatal serotonin reuptake inhibition on food intake, fat pad mass, plasmatic triglycerides/cholesterol and gene expression of hypothalamic peptides (POMC, NPY) and serotonin receptors (5-HT1B, 5-HT2C). METHODS: In each litter, 8 pups were divided into two groups: control (C) and fluoxetine (F). From the 1(st) to the 21(st) postnatal day, C pups received sterile saline while F pups received fluoxetine (10mg/kg). From 180 to 215 days, a group of rats from C and F groups were fed hypercaloric diet (CH and FH, 421.4Kcal/100 g) while the rest of animals from C and F groups fed chow diet (CC and FC). RESULTS: The use of hypercaloric diet was associated with lower accumulation of white adipose tissue in adult rats subjected to neonatal serotonin reuptake inhibition. Adult rats of group FC showed decreased 5-HT2C and neuropeptide Y mRNA expression compared with control chow diet group (CC). After chronic use of a hypercaloric diet, the expression of 5-HT2C was higher in the FH group than the FC group and neuropeptide Y expression decreased in FH related to FC. CONCLUSIONS: These findings suggest that neonatal serotonin reuptake inhibition is associated with better adaptation to hypercaloric diet in adult rats.