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Auto-Immune Diseases: Type I Diabetes    
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Diabetes Type I: possible causes

Diabetes Type I is not a new disease.  There are records of Type I Diabetes existing in ancient Egypt.  Today, there are several explanations being considered, including viruses, drugs, and chemicals.  But there is significant evidence that Type I Diabetes usually results from a combination of both pre-disposed genetics and environmental factors.

Environmental Factors

Viruses
There is considerable evidence that viruses induce Type I Diabetes, as well as some other autoimmune disorders.  Our immune system works by recognizing the shape of the proteins on the surface of cells and other particles.  When viruses infect cells in the body, they cause the cells to produce abnormal proteins. Our immune system learns to recognize these abnormal proteins and uses them to target the infected cells and repress the infection. Scientists think that in the case of diabetes, a particular virus enters the body that causes cells to create abnormal proteins that are similar to the proteins of the insulin-making cells.  So as the immune system starts to respond, the immune cells also mistakenly recognize the healthy pancreas cells, and start to attack them.

This concept is called molecular mimicry, because healthy cells “mimic” the surface proteins of viruses, causing T cells to attack.  Some of these viruses are relatively common:  coxsackie and rota viruses which commonly cause intestinal infections in infants and children, and others like the viruses that cause rubella and mumps.

Chemicals and Drugs
Another theory is that some preservatives found in certain foods cause Type I Diabetes. Nitrosamines, a nitrite preservative that can be found in some meat and cheese products, as well as fish, fish byproducts, and pesticides are known carcinogens in both humans and animals, and they are currently being linked to Type I Diabetes. 

Cow’s milk has also been associated with Type I Diabetes onset. 

Researchers in Finland carried out studies that positively linked babies with Type I Diabetic parents and cow’s milk.  They suggest that the immune system can attack the Insulin hormone found in cow’s milk, and can then turn mistakenly to attack human pancreatic insulin-making cells. Although there is not yet enough research to make substantial claims connecting cow’s milk and Type I Diabetes, this study does highlight the connection between genetic predisposition and environmental factors.

The drug Streptozotocin, derived from a soil bacteria, is a proven cause of Type I Diabetes.  It directly destroys Islet cells, and so today is only used to treat pancreatic cancers. First introduced in antibiotic form in the 1950’s, it was not known as a cause of Diabetes until the 1960’s.  Animal studies indicate that drugs containing alloxan destroys Islet cells in the pancreas, and is used to induce Type I Diabetes in laboratory rodents.  Thiazide diuretics are also linked to Type I Diabetes.

Genetics
Just because someone’s parent has Type I Diabetes does not mean he or she is guaranteed to inherit the disease, but chances are much higher than children of non-Diabetic parents.  Why is this?  Researchers have a few ideas.  Scientists have located the gene sequence that codes for the surface proteins on the insuling-making cells that T cells mistakenly read as signs of infected cells.

Current Research:
Read more about gene mutations that can lead to Diabetes Type I here.

Another cause could be mutations of genes that dictate certain cells in the immune system.  One specific gene controls the reactivity of certain molecules of the immune system, the cytokines.  The mutated gene increases the reactivity of the cytokines, and so causes the destruction of the Islet cells.  Scientists believe that gene mutations linked to Type I Diabetes are also responsible for the onset of additional autoimmune diseases, like lupus and arthritis.



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