Thursday, November 14, 2013

The secret stuff that protects us from stress


Chronic stress affects large areas of the brain, especially the hippocampus, frontal lobe and other parts of the brain.  It affects the connectivity between neuronal hubs of the brain, and thus informational exchange between distal areas. Furthermore, it exerts a negative effect on non-emotional learning mechanisms, which are responsible with exploring and learning novel and complex aspects, different to the ones already known. New studies found that chronic stress accelerates aging by shortening some components of the chromosomes from our DNA. Can we protect ourselves from these deleterious effects?

Imaging studies conducted on Afghanistan veterans, before and after their deployment, revealed that prolonged stress reduces the activity and integrity of the mesencephalon (a structure at the base of the brain, in proximity of the spinal cord) and this alteration affects sustained attention. These changes seem to reverse to normal 1.5 years later after stress cessation. Conversely, combat stress induces persistent reduction of the connectivity between the mesencephalon and frontal cortex. Therefore, stress-induced alterations are only partially reversible. Also, stress-generated enhancement of stress hormones affects working memory process in the medial prefrontal cortex. This data clarifies why subjects with post-traumatic stress like Veterans of the Vietnam war fail to recall personal memories, and why this failure is more accentuated after exposure to traumatic scenes. We might even say that what we call chronic depression is a degenerative disease that affects the brain’s capacity to adapt to novel environments.

The stress response is generally transient, because its effects (immunosuppression, inhibition of growth and enhanced catabolism) yield long-lasting damage. Nonetheless, when stress becomes chronic, it is accompanied by digestive and cardiovascular problems. Furthermore, it affects DNA. This consequence may prompt genesis of tumors, neuropsychiatric disorders and accelerated aging. People suffering from depression may be aging faster than other people, according to a new study. Hence in a Netherlands Study of Depression and Anxiety involving about 1,900 people ranged from 18 to 65 year old who had major depressive disorders at some point during their lives, along with 500 people who had not had depression, scientists found that patients with major depressive disorder (MDD) have an increased onset risk of aging-related somatic diseases such as heart disease, diabetes, obesity and cancer. This suggests mechanisms of accelerated biological aging among the depressed, which can be indicated by a shorter length of telomeres. Telomeres are "caps" at the end of chromosomes that protect the DNA during cell division. Normally, telomeres shorten slightly each time cells divide, and their length is thought to be an index of a cell's aging.

The researchers found telomeres were shorter in people who had experienced depression compared with people in the control group. The length of telomeres is measured in terms of their number of DNA building blocks, called base pairs (bp). In the study, the telomeres in healthy people were about 5,540 bp long on average, whereas people with depression had telomeres about 5,460 bp long. In line with previous studies, the researchers found that with each year of age, telomeres shortened by 14 bp, on average. This suggests cellular aging in people with depression is accelerated by several years. Furthermore, the severity of a person's depression as well as a longer duration of symptoms were linked with shorter telomere length those with the most severe and chronic MDD showed the shortest telomeres, and those with remitted MDD had shorter telomere than controls) and the results held after controlling for weight, smoking, drinking and several other factors that may contribute to aging. The authors said that it is possible that telomere shortening is a consequence of impairment in the body's stress system.

These findings might help explain the variety of health complaints often experienced by people with major depression.  Other studies have shown that people with depression are at increased risk for diseases that tend to come with aging — for example, dementia, cancer and type 2 diabetes — even when health and lifestyle factors are taken into account. This has raised the question whether depression accelerates aging. An important question remains whether this aging process can be reversed. It is possible that lifestyle changes could lengthen telomeres. A healthy lifestyle, such as enough physical exercise, not smoking and a healthy diet, might be of even greater importance in depressed individuals than it is in the non-depressed. But can we be more specific? Yes. A few years ago scientists discover a protein which seems to have the property to offer us protection against stress. It is called Delta Fos B. Studies made on animals shown that a higher concentration of this protein in the brain regions associated with pleasure and motivation plays a critical role in not developing post-traumatic stress, even when the animals were exposed to stressful stimuli. You will say: “Ok, but if I don’t have a high concentration of Delta Fos B, what should I do? Can I take it by spoon?” No you can. But you can do something else. Exposure to an enriched environment stimulates the secretion of this protein. What is “enriched environment”? Is a combination of new places, were you can play or work with new tools or objects, interact with new people and make physical exercise. Not one day, but several months.

If you don’t want to get depressed, lose your memory, attention, and age fast you should learn how to explore, in the same way you have done when you were a child. So, try to be a child with the mind of an adult if you want to keep your mind.