Modulation of hypothalamic AMPK and hypothalamic neuropeptides in the control of eating behavior: A systematic review.

Eating behavior is regulated by central and peripheral signals, which interact to modulate the response to nutrient intake. Central control is mediated by the hypothalamus through neuropeptides that activate the orexigenic and anorexigenic pathways. Energy homeostasis depends on the efficiency of these regulatory mechanisms. This neuroendocrine regulation of hunger and appetite can be modulated by nutritional sensors such as adenosine monophosphate-activated protein kinase (AMPK). Thus, this systematic review discusses the literature on correlations between AMPK and hypothalamic neuropeptides regarding control of eating behavior. Lilacs, PubMed/Medline, ScienceDirect, and Web of Science were searched for articles published from 2009 to 2021 containing combinations of the following descriptors: "eating behavior," "hypothalamus," "neuropeptide," and "AMPK." Of the 1330 articles found initially, 27 were selected after application of the inclusion and exclusion criteria. Of the selected articles, 15 reported decreased AMPK activity, due to interventions using angiotensin II infusion, fructose, glucose, cholecystokinin, leptin, or lipopolysaccharide (LPS) injection; dietary control through a low-protein diet or a high-fat diet (60 % fat); induction of hyperthyroidism; or injection of AMPK inhibitors. Seven studies showed a decrease in neuropeptide Y (NPY) through CV4 AICAR administration; fructose, glucose, leptin, or angiotensin II injections; or infusion of LPS from Escherichia coli and liver kinase B1 (LKB1) overexpression. Eleven studies reported a decrease in food consumption due to a decrease in AMPK activity and/or hypothalamic neuropeptides such as NPY. The results indicate that there is a relationship between AMPK and the control of eating behavior: a decrease in AMPK activity due to a dietary or non-dietary stimulus is associated with a consequent decrease in food intake. Furthermore, AMPK activity can be modulated by glucose, thyroid hormones, estradiol, leptin, and ghrelin.

Predictors of stress in college students during the COVID-19 pandemic.

Background: College students experience high stress levels during emergency remote classes in the COVID-19 pandemic. However, it is not clear whether this is due to the summation effect of both stressors (classes and pandemic). Therefore, the aim of this study was to investigate predictors of stress in college students before and during remote classes five months after the beginning of the COVID-19 pandemic. Methods: The study was conducted before (BRC, July-August 2020) and during remote classes (DRC, October-November 2020). The sample consisted of 177 individuals (80 in BRC, 97 in DRC). Students were asked to self-collect saliva for cortisol analysis at each moment of the study, and to fill out a form to characterize the individual and assess the chronotype (Morningness-Eveningness Questionnaire), sleep quality (Pittsburgh Sleep Quality Index) and the stress (Perceived Stress Scale-10). Results: There was no difference between the evaluated periods for cortisol, perceived stress or sleep quality. Predictors for cortisol levels were gender, academic semester, chronotype, sleep quality and sadness due to pandemic (p<0.001). Limitations: Short interval between BRC and DRC assessments of perceived stress and salivary cortisol. Conclusions: Age, sex, income, academic semester, chronotype, and the impact of the pandemic on mood are predictors of stress among college students. In addition, emergency remote classes and sleep quality contribute to less stress.