Links between stress and sickness

A Michigan State University researcher is providing new insight into how certain types of stress interact with immune cells and can regulate how these cells respond to allergens, ultimately causing physical symptoms and disease. A stress receptor, known as corticotropin-releasing factor, or CRF1, can send signals to certain immune cells, called mast cells, and control how they defend the body.

Mast cells become highly activated in response to stressful situations the body may be experiencing. When this happens, CRF1 tells these cells to release chemical substances that can lead to inflammatory and allergic diseases such as irritable bowel syndrome, asthma, life-threatening food allergies and autoimmune disorders such as lupus.

One chemical substance, histamine, is known to help the body get rid of invading allergens such as pollen, dust mites or the protein of a particular food like a peanut or shellfish. The histamine causes an allergic reaction and in a normal response, helps the body clear the allergen from its system.
If a patient has a severe allergy or is under a lot of stress, then this same response can be amplified, resulting in more severe symptoms ranging from trouble breathing, anaphylactic shock or death.

Researchers compared the histamine responses of mice to two types of stress conditions - psychological and allergic - where the immune system becomes overworked. One group of mice was considered "normal" with CRF1 receptors on their mast cells and the other group had cells that lacked CRF1. While the 'normal' mice exposed to stress exhibited high histamine levels and disease, the mice without CRF1 had low histamine levels, less disease and were protected against both types of stress. This shows that CRF1 is critically involved in some diseases initiated by these stressors.

The CRF1-deficient mice exposed to allergic stress had a 54 percent reduction in disease, while those mice who experienced psychological stress had a 63 percent decrease. The results could change the way everyday disorders such as asthma and the debilitating gastrointestinal symptoms of irritable bowel syndrome are treated.
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Links between microbiomes and autoimmune disorders

Bacteria in human body have all kinds of positive effects on our health, the bacteria in the gut have many beneficial functions. They help in digestion, prevent infection by pathogens and strengthen immune system to fight diseases.

A new function of a protein in the gut microbiome reveals potential impacts for those who suffer from inflammatory bowel disease IBD. A protein expressed by gut bacteria called Bacteroides works to prevent IBD by rapidly recruiting white blood cells to kill a cell of the immune system that is responsible for orchestrating IBD.

However, there is a flipside to the protein's call for help. In some people, the white blood cells overreact to the presence of the IBD bacteria. This is what causes problems like IBD, it's not the bacteria itself, but the immune system's severe reaction triggered by the protein.

These same overstimulated white blood cells are also the cells that cause other autoimmune disorders like diabetes, this discovery demonstrates the effect the gut microbiome has on the immune system and unearths a novel mechanism through which changes in the gut microbiome can increase the risk of autoimmune disorders.
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Anorexia could be genetic

Anorexia is an eating disorder that makes  people to lose more weight than is considered healthy for their age and height.

People with this disorder are afraid of gaining weight, even when they are underweight. They may diet, exercise or use different methods to lose weight.

The study included genome-wide analysis of DNA from 3,495 individuals with anorexia nervosa and 10,982 unaffected individuals.

If particular genetic variations are significantly more frequent in people with a disorder compared to unaffected people, the variations are said to be related with the disorder.

Associated genetic variations can serve as powerful pointers to regions of the human genome where disorder-causing problems reside, according to the National Human Genome Research Institute.

Genome-wide significant locus for anorexia nervosa on chromosome 12, in a region previously shown to be associated with type 1 diabetes and autoimmune disorders.

Anorexia nervosa was significantly genetically correlated with neuroticism and schizophrenia. There is strong
genetic correlations with various metabolic features including body composition (BMI) and insulin-glucose metabolism.