Repeated Emotional Stress Triggers Process that Leads to Alzheimers Disease
A little bit of stress is a natural, normal body response that is actually in place for protection. However, chronic repeated stresses are detrimental to your health. Those people who are prone to stress have a greater risk of later developing Alzheimer’s disease and researchers with the University of California, San Diego School of Medicine may have pinpointed why this happens.
The Natural Stress Response Goes Haywire
The body is hard-wired to react to stress against threats from predators and other aggressors. Although such threats today are quite rare, we still face multiple demands which the body treats as bodily assaults. Through a combination of nerve and hormonal signals, the hypothalamus sets off an alarm which prompts the adrenal glands to release a surge of hormones, including adrenaline and cortisol.
Adrenaline increases the heart rate, elevates the blood pressure and boosts energy supplies. Cortisol increases glucose in the bloodstream, enhances the brain’s use of glucose and increases the availability of substances that repair tissues.
This system is normally self-regulating and returns hormones levels back to normal once the perceived threat is removed.
However, for those who are under constant stress, the stress-response system remains on – putting you at risk for numerous health problems such as heart disease and memory impairment.
Stress and Tau Protein Aggregation
Robert A. Rissman PhD, an assistant professor of neurosciences, found that repeated stress triggers the production and accumulation of tau protein aggregates inside the brain cells of mice. These are similar to neurofibrillary tangles, or NFTs, which are one of the physiological hallmarks of Alzheimer’s disease.
The effect was most notable in the hippocampus, the region of the brain linked to the formation, organization, and storage of memories.
“In the mouse models, we found that repeated episodes of emotional stress, which has been demonstrated to be comparable to what humans might experience in ordinary life, resulted in the phosphorylation and altered solubility of tau proteins in neurons,” Dr. Rissman said. “These events are critical in the development of NFT pathology in Alzheimer’s disease.”
Short-term (acute) stress – a single, passing episode - does not likely have lasting, debilitating changes. Dr. Rissman notes that “a little stress” may actually be good for us. “Acute stress may be useful for brain plasticity and helping to facilitate learning,” he said.
Stress Management Good for Everyone
If you have stress symptoms, taking steps to manage the stress can have a number of health benefits. Physical activity is a great stress reliever, including mind-body exercises such as tai-chi and yoga. Meditation and other relaxation techniques are also beneficial.
Also remember that spouses and caregivers of patients with Alzheimer’s need some stress relief too. Studies suggest that the stress of caring for an AD patient makes one more likely to develop Alzheimer’s themselves. Good social support is critical for everyone in these cases.
Robert A. Rissman, Michael A. Staup, Allyson Roe Lee, Nicholas J. Justice, Kenner C. Rice, Wylie Vale, and Paul E. Sawchenko. Corticotropin-releasing factor receptor-dependent effects of repeated stress on tau phosphorylation, solubility, and aggregation.Proceedings of the National Academy of Sciences, 2012 DOI: 10.1073/pnas.1203140109