Stress hormone helps control the circadian rhythm of brain cells
November 8, 2019
Science Daily/University of Copenhagen The Faculty of Health and Medical Sciences
Researchers have shown how the brain's circadian rhythm in rats is, among other things, controlled by the stress hormone corticosterone -- in humans called cortisol. This has been shown by means of a completely new method in the form of implanted micropumps.
As day turns into night, and night turns into day, the vast majority of living organisms follow a fixed circadian rhythm that controls everything from sleep needs to body temperature.
This internal clock is found in everything from bacteria to humans and is controlled by some very distinct hereditary genes, known as clock genes.
In the brain, clock genes are particularly active in the so-called suprachiasmatic nucleus. It sits just above the point where the optic nerves cross and sends signals to the brain about the surrounding light level. From here, the suprachiasmatic nucleus regulates the rhythm of a number of other areas of the body, including the cerebellum and the cerebral cortex.
However, these three areas of the brain are not directly linked by neurons, and this made researchers at the University of Copenhagen curious. Using test rats, they have now demonstrated that the circadian rhythm is controlled by means of signalling agents in the blood, such as the stress hormone corticosterone.
'In humans, the hormone is known as cortisol, and although the sleep rhythm in rats is the opposite of ours, we basically have the same hormonal system', says Associate Professor Martin Fredensborg Rath of the Department of Neuroscience.
He explains that recent years have seen an increasing, scientific focus on research on clock genes, one reason being that previous research on clock genes have found a correlation between depression and irregularities in the body's circadian rhythms.
New Method with Medical Micropumps
In the study with the stress hormone corticosterone, the researchers removed the suprachiasmatic nucleus in a number of rats. As expected, this removed the circadian rhythm of the animals.
Among other things, the body temperature and activity level of the rats went from circadian oscillations to a more constant state. The same was true of the otherwise rhythmic hormone production.
However, the circadian rhythm of the cerebellum was restored when the rats were subsequently implanted with a special programmable micropump, normally used to dose medication in specific quantities.
In this case, however, the researchers used the pump to emit carefully metered doses of corticosterone at different times of the day and night, similar to the animals' natural rhythm.
'Nobody has used these pumps for anything like this before. So technically, we were onto something completely new', says Martin Fredensborg Rath.
For that reason, the researchers spent the best part of a year carrying out a large number of control tests to ensure that the new method was valid.
Interaction Between Neurons and Hormones
As mentioned, the new method paid off. With the artificial corticosterone supplement, researchers were again able to read a rhythmic activity of clock genes in the cerebellum of the rats, even though their suprachiasmatic nucleus had been removed.
'This is hugely interesting from a scientific point of view, because it means that we have two systems -- the nervous system and the hormonal system -- that communicate perfectly and influence one another. All in the course of a reasonably tight 24-hour programme', says Martin Fredensborg Rath.
With the test results and the new method in the toolbox, the researchers' next step is to study other rhythmic hormones in a similar manner, including hormones from the thyroid gland.
https://www.sciencedaily.com/releases/2019/11/191108102850.htm
Stress can impair memory, reduce brain size in middle age
October 25, 2018
Science Daily/University of Texas Health Science Center at San Antonio
Stress may be causing impaired memory and brain shrinkage in middle-age adults, even before symptoms of Alzheimer's or other dementia begin, according to a new study.
Adults in their 40s and 50s with higher levels of cortisol -- a hormone linked to stress -- performed worse on memory and other cognitive tasks than peers of the same age with average cortisol levels, research found. Higher cortisol in the blood also was associated with smaller brain volumes, according to the study, published Oct. 24 in Neurology, the medical journal of the American Academy of Neurology.
"In our quest to understand cognitive aging, one of the factors attracting significant interest and concern is the increasing stress of modern life," said study senior author Sudha Seshadri, M.D., professor of neurology at UT Health San Antonio and founding director of the university's Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases. "One of the things we know in animals is that stress can lead to cognitive decline. In this study, higher morning cortisol levels in a large sample of people were associated with worse brain structure and cognition."
The cognitive data are from 2,231 participants in the Framingham Heart Study, for which Dr. Seshadri is a senior investigator; 2,018 participants also underwent magnetic resonance imaging (MRI) to measure brain volume. The team included Framingham collaborators at Harvard Medical School; the National Heart, Lung, and Blood Institute; Boston University School of Medicine; the University of California, Davis, at Sacramento; and UT Health San Antonio.
Blood serum cortisol, which varies in level throughout the day, was measured in early morning (between 7:30 and 9 a.m.) in each fasting participant. The study featured a relatively young sample of male and female participants (mean age 48.5).
"Cortisol affects many different functions, so it is important to fully investigate how high levels of the hormone may affect the brain," said study lead author Justin B. Echouffo-Tcheugui, M.D., Ph.D., of Harvard Medical School. "While other studies have examined cortisol and memory, we believe our large, community-based study is the first to explore, in middle-aged people, fasting blood cortisol levels and brain volume, as well as memory and thinking skills."
Memory loss and brain shrinkage were found in the study's middle-age participants before the onset of any symptoms, Dr. Echouffo-Tcheugui noted. He said it is important for physicians to counsel people with higher cortisol levels on ways to reduce stress, such as getting enough sleep and engaging in moderate exercise.
"The faster pace of life today probably means more stress, and when we are stressed, cortisol levels increase because that is our fight-or-flight response," Dr. Seshadri said. "When we are afraid, when we are threatened in any way, our cortisol levels go up. This study adds to the prevailing wisdom that it's never too early to be mindful of reducing stress."
Findings were adjusted for factors including age, sex, smoking and body mass index. The team asked whether having APOE4, a genetic risk factor for cardiovascular disease and Alzheimer's disease, might be associated with higher cortisol level. This did not prove to be the case.
https://www.sciencedaily.com/releases/2018/10/181025084043.htm
Pregnant women with PTSD have higher levels of stress hormone cortisol
December 5, 2017
Science Daily/University of Michigan
A woman's emotional and physical health during pregnancy impacts a developing fetus, research shows. However, less is known about the effect of past stressors and posttraumatic stress disorder on an expectant woman.
To that end, researchers at the University of Michigan measured the stress hormone cortisol in pregnant women from early pregnancy to when their baby was 6 weeks old. They found that those with a dissociative type of PTSD that's often related to childhood abuse or trauma had levels up to 10 times higher than their peers.
These toxic levels of cortisol may contribute to health problems in the next generation, said Julia Seng, professor of nursing and lead author on the study.
"We know from research on the developmental origins of health and disease that the baby's first environment in its mother's body has implications for health across the lifespan," Seng said. "Higher exposure to cortisol may signal the fetus to adapt in ways that help survival, but don't help health and longevity. This finding is very useful because it helps us know which women are most likely to exhibit the highest level of stress and stress hormones during pregnancy and postpartum."
Cortisol is sometimes called the stress hormone because it's released in stressful situations as part of the flight-or-fight response. Cortisol levels that stay high are linked to serious health problems such as heart disease and high blood pressure, and can fuel weight gain, depression and anxiety plus a host of other problems. The effect of elevated cortisol on a developing fetus isn't well understood, but high cortisol and stress also contribute to preterm birth
In the study, 395 women expecting their first child were divided into four groups: those without trauma, those with a trauma but no PTSD, those with classic PTSD and those with dissociative PTSD.
Researchers measured salivary cortisol at different times during the day. Then 111 of those women gave saliva specimens until postpartum. The difference in cortisol was greatest in early pregnancy, when levels were eight times higher in the afternoon and 10 times higher at bedtime for the dissociative group than for other women.
About 8 percent of pregnant women in the study had PTSD, a disorder that results when symptoms of anxiety and fear persist well after exposure to stressful events. About 14 percent of that group had the more complex dissociative PTSD, which was associated with higher cortisol.
"It's been a mystery in our field why cortisol is sometimes high with PTSD and sometimes not," Seng said. "This finding that in pregnancy it's only the dissociative subgroup that has high cortisol gives us more to go on for future research."
Seng was surprised at how high the cortisol was in the dissociative group. She also said researchers expected women with classic PTSD to experience elevated cortisol as well, and the fact that they didn't is good news.
"We can do something for the 1-to-2 out of 100 pregnant women who have this dissociative PTSD," Seng said. "We can work with them to make pregnancy, maternity care, labor, breastfeeding and early parenting less likely to trigger stress reactions. And we can connect them to mental health services when they are ready to treat their PTSD."
Seng and collaborator Mickey Sperlich have developed a PTSD-specific education program for pregnant woman with a childhood trauma called the Survivor Moms' Companion, which has been piloted in Michigan and is currently being piloted in England.
https://www.sciencedaily.com/releases/2017/12/171205130121.htm
Want to help your partner stress less? Listen from the heart
February 6, 2018
Science Daily/Wake Forest University
When we feel supported, we feel less stress. But sometimes we think we are being supportive of a romantic partner and we're not. Who hasn't experienced the self-satisfaction of feeling like we're 'helping' only to find we've only made the situation worse.
Wake Forest communication professor Jennifer Priem studies dating relationships and explores the connection between supportive conversations and physiological signs of stress reduction.
Using saliva samples, Priem can measure changes in stress by determining when cortisol levels rise and when they fall as a result of support conversations between dating partners. Cortisol is a stress hormone that, when over active can cause heart disease as well as other health problems such as headaches, sleep problems, and concentration impairment.
A supportive partner has the power to reduce the levels of cortisol by taking specific actions that help calm tension and reduce stress. Supportive communication can alleviate distress and improve a partner's emotional state.
"The fastest stress recovery comes from explicit messages," says Priem. "When a partner is stressed they are unable to focus on interpreting messages well. Clarity and eye contact help."
Other features of supportive communication that have been shown to reduce stress include:
· Acknowledging the person is under stress and experiencing a problem. We are generally most willing to give high quality comforting when we can interpret the stress at the same level as the person needing support. Even if, and maybe especially when, you don't think the other person should be stressed, he or she still needs support. "If your partner is feeling stressed, telling him or her 'don't worry about it' or trying to distract the person from the stress by changing the subject is generally not going to help," Priem says.
· Using verbal and nonverbal forms of communication, such as listening and asking questions, making eye contact, nodding and touching, can cause cortisol levels go down, and there is often a reappraisal of the problem by the person who is upset.
· Listening and understanding is support validation and turns off strong emotional responses by legitimizing feelings. We often feel the need to say the right thing or fix the problem, but most often when people are stressed they want emotional support, which mainly consists of listening intently and asking questions. Unless someone specifically asks for advice, do not offer it. Once you validate their feelings, people may ask for advice, but they have to be ready to hear it.
· Adjusting your approach as needed. It's possible that as a support provider you may think you are providing good support. But good support isn't good unless the person receiving the support perceives it as helpful.
"Cookie cutter support messages don't really work," says Priem. "Stress creates a frame through which messages are interpreted. Support that is clear and explicit in validating feelings and showing interest and concern is most likely to lower cortisol levels and increase feelings of wellbeing and safety. If you aren't seeing improvement in your partner's anxiety, you may need to change your approach."
The benefit both partners will receive from engaging in effective support goes beyond the immediate stress recovery after the conversation. The result of prolonged exposure to stress hormones, such as cortisol, is wear and tear on the body. Because the rate of physiological recovery after exposure to everyday stressors and hassles results in more or less cortisol exposure over the course of a lifetime, supportive communication that accelerates cortisol recovery, even slightly, may have longer health benefits. Thus, individuals who are able to facilitate faster stress recovery for their partner create immediate and long term relational and health benefits, strengthening the relationship and the individual.
https://www.sciencedaily.com/releases/2018/02/180206115534.htm
Hair cortisol levels predict which mothers are more likely to suffer postpartum depression
November 13, 2017
Science Daily/University of Granada
Researchers from the University of Granada (UGR), who belong to the Brain, Mind and Behavior Research Center (CIMCYC, from its abbreviation in Spanish) and the Faculty of Psychology, have proven that cortisol levels (a steroid hormone secreted as a response to stress) present in the hair of pregnant women during the first or third trimesters of pregnancy may indicate which of them are more likely to suffer postpartum depression.
Their work, published in the PLoS ONE journal, showed that hair cortisol levels in women who developed postpartum depression were higher throughout pregnancy than those seen in women who hadn't developed it, being that difference statistically more significant during the first and third trimesters.
The UGR researchers carried out their study doing a follow-up on 44 pregnant women throughout the whole gestation period and after giving birth. Each trimester the mothers underwent a series of tests that evaluated their stress and psychopathological symptoms while simultaneously taking hair samples from which the researchers extracted the cortisol corresponding to the last three months.
The following days after labor the researchers evaluated the mothers' emotional state in order to assess who among them had developed postpartum depression.
Quarterly psychopathological symptoms
Additionally, the results of the study showed that the participants which developed postpartum depression showed higher levels of somatization during the first trimester. During the second trimester they showed higher levels of somatization, obsession-compulsion, depression and anxiety, and during the third trimester they showed higher levels of somatization and pregnancy-specific stress. Therefore, all those symptoms along with higher levels of cortisol would be indicators of a future postpartum depression.
As María Isabel Peralta Ramírez, lead researcher of the project says, the consequences of those results are very important in the prevention of postpartum depression, "since they show that there are various altered psychological and hormonal variables throughout the whole gestation period in comparison to those women who will not suffer postpartum depression. Detecting those differences is the key to anticipate the psychological state of the mother as well as the consequences for the baby that said state could mean."
This study belongs to the GESTASTRESS research project, in the research excellence framework of the Spanish Ministry of Economy and Competitiveness. Its primary goal has been to assess the effects of psychological stress on the mother throughout the whole gestation period as well as on birth variables, and on the baby's stress and neurodevelopment.
https://www.sciencedaily.com/releases/2017/11/171113111040.htm
Stress reduction and mindful eating curb weight gain among overweight women
December 7, 2011
Science Daily/University of California - San Francisco
Mastering simple mindful eating and stress-reduction techniques helped prevent weight gain even without dieting in overweight women.
In a study by UCSF researchers published online in the Journal of Obesity, mastering simple mindful eating and stress-reduction techniques helped prevent weight gain even without dieting.
Women in the study who experienced the greatest reduction in stress tended to have the most loss of deep belly fat. To a greater degree than fat that lies just under the skin, this deep abdominal fat is associated with an elevated risk for developing heart disease or diabetes.
"You're training the mind to notice, but to not automatically react based on habitual patterns -- to not reach for a candy bar in response to feeling anger, for example," said UCSF researcher Jennifer Daubenmier, PhD, from the Osher Center for Integrative Medicine. "If you can first recognize what you are feeling before you act, you have a greater chance of making a wiser decision."
Daubenmier led the current study with UCSF psychologist Elissa Epel, PhD. The study, published online in October, is part of ongoing UCSF research into how stress and the stress hormone cortisol are linked to eating behavior, fat and health.
Recognizing Sensations of Hunger, Fullness and Taste Satisfaction
The women who participated were not on calorie-counting diets. Instead, 24 of the 47 chronically stressed, overweight and obese women were randomly assigned to mindfulness training and practice, and the other 23 served as a control group. Although no diets were prescribed, all participants attended one session about the basics of healthy eating and exercise.
The training included nine weekly sessions, each lasting 2 1/2 hours, during which the women learned stress reduction techniques and how to be more aware of their eating by recognizing bodily sensations -- including hunger, fullness and taste satisfaction. At week six they attended an intensive seven-hour, silent meditation retreat.
They were asked to set aside 30 minutes daily for meditation exercises and to practice mindful eating during meals. Researchers used a scientifically tested survey to gauge psychological stress before and after the four-month study, and recorded the women's fat and cortisol levels.
Among women in the treatment group, changes in body awareness, chronic stress, cortisol secretion and abdominal fat were clearly linked. Those who had greater improvements in listening to their bodies' cues, or greater reductions in stress or cortisol, experienced the greatest reductions in abdominal fat.
Among the subset of obese women in the study, those who received the mindfulness training had significant reductions in cortisol after awakening and also maintained their total body weight, compared to women in the waitlist group, who had stable cortisol levels and continued to gain weight.
In a separate, ongoing study with lower-income, pregnant women who are overweight, Epel,Daubenmier and colleagues are teaching similar mindful-eating techniques. Pregnancy is a time when heavy women tend to gain an excessive amount of weight and later find it very hard to lose it. Furthermore, excessive weight gain during pregnancy can harm the baby's health.
"We are intervening at a critical point, when the health of the next generation is being shaped,"Epel said. "We hope to improve the health of both the mothers and their babies."
http://www.sciencedaily.com/releases/2011/12/111207152418.htm
Women in mostly male workplaces exhibit psychological stress response
August 24, 2015
Science Daily/Indiana University
Today's workforce is highly sex-segregated -- for example, most elementary school teachers are women, while most chemistry professors are men. Researchers examine one important consequence of this occupational sex segregation: the stress exposure of women working in highly male-dominated occupations.
"We find that such women are more likely to experience exposure to high levels of interpersonal, workplace stressors," Manago said.
Previous research has shown that women working in male-dominated occupations face particular challenges. They encounter social isolation, performance pressures, sexual harassment, obstacles to mobility, moments of both high visibility and invisibility, co-workers' doubts about their competence, and low levels of workplace social support. Chronic exposure to these types of social stressors is known to cause vulnerability to disease and mortality through dysregulation of the human body's stress response.
Manago and Taylor measure whether women in occupations that were made up of 85 percent or more men, also known as "token" women, show such dysregulation by analyzing their daily cortisol patterns. Cortisol is a stress hormone that naturally fluctuates through the day, but people with high levels of interpersonal stress exposure have different patterns of fluctuation than people exposed to more average levels of stress.
"We find that women in male-dominated occupations have less healthy, or 'dysregulated,' patterns of cortisol throughout the day," Manago said. "We use nationally representative data, the MIDUS National Study of Daily Experiences, which allow us to assess women's cortisol profiles in workers across the United States.
"We also use statistical techniques to account for individuals' occupational and individual-level characteristics, allowing us to be more confident that the dysregulation of cortisol profiles we observe is due to the negative working conditions of token women, and not their own personal characteristics nor the characteristics of their occupations."
Previous work has shown that women in male-dominated occupations encounter difficult and negative workplace climates. And previous researchers have hypothesized that exposure to such difficult and negative workplace climates can expose these women to chronic stress. The IU research is the first to demonstrate that such negative workplace climates can be expressed in these women's bodies and can, in fact, dysregulate their stress response, potentially for years after the exposure to the stressful workplace climate.
"Our findings are especially important because dysregulated cortisol profiles are associated with negative health outcomes," Taylor said. "Thus, our project provides evidence that the negative workplace social climates encountered by women in male-dominated occupations may be linked to later negative health outcomes for these women."
http://www.sciencedaily.com/releases/2015/08/150824130459.htm