With information from UNAM:
Obesity not only has to do with eating behavior or sedentary lifestyle, factors such as lack of synchronicity in our daily activities and the cycles of light and dark in the environment also contribute. Thus, sleep deprivation, night work or 24 by 24 hours are stressors that contribute to this condition.
Labor or social requirements (social jet lag) That cause us to sleep later or wake up earlier than our biological clock requires have negative health consequences.
Based on this premise, Lucía Mendoza Viveros, postdoctoral researcher at the Institute for Biomedical Research (IIBm) of UNAM, studies biological rhythms in mammals. “We take care to see how the body regulates the processes that vary throughout the day; one of them is metabolism ”.
Psychologist and Master in Biochemical Sciences from UNAM, and PhD in Cell and Systems Biology from the University of Toronto, she analyzes the relationship between biological clocks and metabolism, and how pathologies occur when they are not synchronized.
Winner of the L'Oreal-UNESCO- Conacyt-AMC 2019 Scholarship for Women in Science, for her project "Hypothalamic clocks in the central control of metabolism", the young scientist evaluates some parameters of this last process and of the physiology of obesity induced by diet.
Although this research is carried out in animals (mice), it is highly relevant, especially due to the prevalence of obesity among the Mexican population. It is a pathological condition that entails many health problems and detriment to people's quality of life, he said.
This project, started last year, is the result of collaboration between the working groups of Lorena Aguilar Arnal, from the IIBm, and Ricardo Orozco Solís, from the National Institute of Genomic Medicine.
Biological clock
“In people, acute sleep deprivation has been shown to affect glucose tolerance and insulin response; that is, the metabolism responds inadequately. When this situation is sustained, during years of night work or sleeplessness, the consequences can be more serious ”, affirmed Mendoza Viveros.
The member of the National System of Researchers explained that biological clocks are intrinsic to organisms; they are found in our cells and at the systemic level.
Meanwhile, the hypothalamus is a part of the brain made up of different nuclei dedicated to controlling the release of hormones, eating behavior, energy expenditure, food metabolism and other related processes. It also participates in reproductive behavior, emotional responses and fluid balance (osmoregulation), among other aspects.
In mammals, the "master clock" or main nucleus is the suprachiasmatic, the center of regulation of circadian rhythms. Its "job" is to know the time, when it is day and when it is night, to inform the rest of the brain that, by releasing hormones or nerve signals, it will let the rest of the organs know.
Other nuclei of the hypothalamus are related to metabolism: the ventromedial nucleus, for example, has to do with the control of glucose in the body, eating behavior and satiety.
Some of the experiments carried out by the 32-year-old girl have consisted of carrying out a chronotherapeutic intervention in wild mice - which have been induced to obesity with a high-fat diet - consisting of withdrawing food from them during the day, because they are nocturnal animals. With this action that encourages energy metabolism to focus on the hours of darkness, the animals are prevented from gaining weight and a favorable response to glucose is generated.
Although analysis remains to be done, so far the scientific team has discovered that animals fed a diet high in fat, and consequently obese, register a pronounced decrease in the activity of genes that are rhythmically expressed.
“We still don't really know what it means, but we can deduce that the fact that fewer transcripts are expressed in a rhythmic way indicates a problem in metabolism; in brown adipose tissue, which is dedicated to expending energy in the form of heat, it could mean that the processes do not happen properly and that increases the weight, because energy is saved ”.
In the group of animals fed a high-fat diet, but which are only allowed to eat at night, when their metabolism is better prepared to receive food and be more efficient, it was found that gene expression patterns are they seem more like the normal condition, not pathological.
"This is one of the results that excites us the most, because with further analysis we will see in a functional way the expression of some genes, how this translates into tissue function and how it impacts the health of the animal, its weight, response to glucose and insulin ”, added the chronobiologist.
The also winner of the "Graduate Research Award" (annual award to a graduate student to recognize excellence in research) from the University of Toronto Mississauga, said she was proud to receive the Scholarship for Women in Science and "to be recognized for my work ; it is motivating to continue every day ”.
With the funding, it will carry out additional experiments to learn more about the physiology of the nuclei of the hypothalamus, for example, how signals are triggered in the neurons of animals subject to nutritional challenges, such as diets high in fat or with a temporary food restriction. at different times of the day.
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