Genome-Wide Changes May Result from Excessive Stress

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Category: Build Your Immunities

Created on Tuesday, 06 October 2020 13:15

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The word “stress” is often used in daily discourse to reflect the pattern of our busy lives. For some, stress comes and goes, but when stress becomes chronic—usually from unresolved uncertainty— serious bodily damage can manifest.¹ During a stressful event, neuroendocrine, cardiovascular, and emotional responses become activated¹ and can disturb the body’s normal physiological equilibrium.² Over the past decade, studies have shown that chronic stress can also induce genome- wide epigenetic changes and the distribution of molecules in the brain,^3,4 the central organ of stress and adaptation to stress.⁵ What’s more, maternal genetic changes that result from high cortisol exposure may even be passed down to future generations.

A 2017 study of patients with Cushing’s Syndrome (CS) in remission found genome-wide changes in DNA methylation.⁷ Patients exposed to high amounts of cortisol, as is characteristic of CS, had less DNA methylation compared to healthy individuals, and these changes were associated with persistent neuropsychological consequences like fatigue, depression, and anxiety. The findings suggest that long- standing hypercortisolism reduces global DNA methylation, specifically in genes that are known to attenuate the sensitivity of the glucocorticoid receptor, and therefore may induce hyperactivity of the HPA axis.⁷

Early Life Stress

Early life adverse events and poor maternal care have been linked to changes in GC receptor (NR3C1) DNA methylation.⁷ Gene-environment interactions are key to how the brain develops, and adverse and stressful childhood experiences (ACE) have a powerful effect on lifelong trajectories of health and disease.³ In fact, stressors that occur early in development have greater and more enduring effects  than stressors that occur in adulthood.³

A 2014 review points to a substantial body of evidence connecting early life stress to later life neurodegenerative, cognitive, cardiometabolic, and psychiatric diseases.⁶ For the fetus, these effects are mediated through alterations in both the maternal and fetal hypothalamic-pituitary-adrenal (HPA) axis leading to in-utero exposure to excess glucocorticoids. After birth, impairment of interactions between mother and infant (like maternal separation or deprivation) was shown to disrupt the neuroendocrine regulations, such as the upregulation of hippocampal glucocorticoid receptor and hypothalamic corticotropin releasing factor, along with increasing corticosterone and adrenocorticotropic hormone levels. These disruptions may cause behavioral problems in adulthood, such as impaired memory and learning, anxiety, and depressive-like behaviors.⁶

The epigenetic effects of stress can also be seen within the womb. Research from 2008 suggests that maternal stress levels may affect the gestational development of a fetus in the third trimester.⁶ In the study, a maternally depressed/anxious mood resulted in the increased methylation of a CpG?rich region in the promoter and exon1F of the GR gene (NR3C1) in the cord blood of newborns, and these  effects on methylation of the NR3C1 gene have been shown to be persistent beyond infancy, suggesting a functional consequence of this epigenetic variation on HPA stress reactivity.⁶

A 2018 population-based study provides empirical support for a relationship between maternal anxiety over time and risk of childhood developmental delays.⁸ The authors of this study suggest that identifying and supporting mothers experiencing high anxiety symptoms in the perinatal period may mitigate the risk of these delays in children.⁸

In addition to epigenetic effects, chronic stress challenges overall health. People living in a volatile and insecure environment have altered brain architecture and a high risk of depression, cognitive impairment, myocardial infarction, and stroke.¹ Chronic stress can also exacerbate pro-inflammatory diseases and increase susceptibility to infections and cancer.⁹

Treatment Options

Patients suffering from chronic stress should be encouraged to improve their sleep quality and   quantity, improve social support, promote a positive outlook on life, maintain a healthy diet, avoid smoking, and undertake regular moderate physical activity.⁵ Clinicians can utilize tools such as Diet, Nutrition, and Lifestyle to identify areas where patients might modify their behavior to achieve positive outcomes. By examining lifestyle choices related to diet and exercise, Functional Medicine practitioners are able to assess the body’s complex physiological processes and help patients make meaningful, lasting lifestyle changes that can decrease chronic disease risk.

Mindfulness-based interventions have also been shown to help alleviate chronic stress–related symptoms.^10,11 Recent empirical research points to several components through which mindfulness meditation exerts its effects: (a) attention regulation, (b) body awareness, (c) emotion regulation, and (d)  change in perspective on the self.¹¹ Functional and structural neuroimaging studies suggest that mindfulness practice is associated with neuroplastic changes in the anterior cingulate cortex, insula, temporoparietal junction, frontolimbic network, and default mode network structures.¹¹

But can meditation effect change at the cellular level? Recent investigations using functional genomics have helped researchers understand the molecular pathways involved in mind-body therapies.¹² A   2014 review supports the correlation of transcriptomic, and thus epigenetic, changes with mind-body therapies like meditation, yoga, tai chi, qigong, biofeedback, progressive muscle relaxation, guided imagery, hypnosis, and deep breathing exercises.¹² A 2017 study found that yoga and meditation-based lifestyle interventions significantly reduced the rate of cellular aging in a healthy population.¹³

Similar genome-regulating effects have been found for Kirtan Kriya meditation¹⁴ and for a mindfulness- based stress reduction program.¹⁵ These data show that psychological interventions can reverse stress- induced genome-wide transcriptional responses, which may in turn have implications for human health.¹⁶ A 2012 study investigated whether tai chi practice resulted in positive epigenetic changes at the molecular level, and found that in the tai chi cohort, all six marks demonstrate significant slowing (by 5-70%) of the age-related methylation losses or gains observed in the controls, suggesting that tai chi practice may be associated with measurable beneficial epigenetic changes.¹⁷

“We are now exposed to chronic stress and chronic sources of inflammation. This is how the Functional Medicine paradigm can help clinicians: not by trying to stop inflammation and stop stress as the drivers of chronic disease, per se, but to help the patient change the way they’re living and change their environment away from an inflammatory environment,” says IFM Executive Director of Medical Education Robert Luby, MD. “Evidence is emerging that positive experiences create a positive milieu in the patient, which promotes health and wellness, including and especially the health of the immune system.”

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References

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