Latest research on diabetic complications

[stauffenberg]

For years the basic theory of type 1 diabetes has been that the disease is caused by a genetic defect in the regulatory mechanism of the immune system, so that in response to some stress the immune system attacks the body's own pancreatic beta cells, depriving the patient of insulin production.  But Professor Denise Faustman of Harvard Medical School has recently discovered evidence suggesting that the fault is not with the immune system, but with the organs of the body which it attacks being deformed in subtle ways, so that the immune system recognizes them as foreign tissues and attacks them.  On this theory, if the beta cells in the diabetic are genetically programmed to develop subtle alterations in their tissue characteristics over time, eventually they come to look so foreign to the immune system that even though it is normal and healthy, it still attacks these tissues.

But Faustman has discovered that in mice genetically prone to diabetes, the ears as well as the beta cells of the pancreas are malformed, inducing an autoimmune attack on both of these sructures.  This raises the interesting possibility that the complications of diabetes could be due not to high blood sugar but to the fact that the various parts of the body which fail eventually in the diabetic -- the kidneys, the nerves, the small blood vessels, the retinas, and the arteries -- are all malformed from the start and simply decline in function more rapidly than in a normal body, either because of their structural faults or because they also attract subtle immune attacks continuing over the years.  This would explain the peak onset of new cases of kidney failure in diabetics 17.5 years after onset of diabetes, independently of blood sugar levels.

[jbeany]

In other words, my genes really suck!

Interesting research, stauffenburg. 

I thought they had decided that the onset of type 1 was generally caused by a virus.  Wonder how that ties in with this?

[stauffenberg]

The genes provide the sensitivity to the virus, which awakens the immune system, which then goes off hunting for tissue that does not look right, destroying it in the assumption that it must be foreign.  Research shows that of genetically identical twins, in only 50% of the cases do both twins have type 1 diabetes if one of them has it.  This means that it cannot all be due to genetics, since otherwise the match would be 100%, so one twin must stumble into some trigger for the genetic time-bomb which the other twin manages to avoid.  There are many culprits now thought to be the trigger, including viruses, bug spray, early nutrition with cow's milk, etc., but it is difficult to imagine why one twin of an identical twin pair would encounter something early in life that the other twin did not.

[jbeany]

Huh.  Bad genes and exposed to bad viruses.  Golly, why haven't I won the lotto yet, with those kinds of odds in my favor?