by Wesley W. Wilson, MD
NOTE: If you have any questions for "Ask the Doctor," please send
them to the VOICE editorial office. The only questions Dr. Wilson will be able
to answer are the ones used in this column.
Wesley W. Wilson, MD has retired as an Internal Medicine practitioner at the Western Montana Clinic in Missoula, Montana. Dr. Wilson was diagnosed with type 1 diabetes in 1956, during his second year of medical school. He remains interested and involved in diabetes education for patients and professionals.
Q: My diabetes educator has been telling us about glycosylation. He says much of the damage I've done over years of overweight and high blood sugars is reversible, if I get my blood glucose down to normal and keep it there. How would that work? How can diabetic complications be reversible?
A: I'm sorry to have to discuss what seem to be misconceptions about glycosylation and diabetic complications. It is true that attachment of glucose to protein (glycosylation) seems to have a key role in the development of many of the complications seen in too many persons with diabetes.
Measurement of the glycosylation of hemoglobin, the red molecule in red blood cells that carries oxygen, is useful since it allows estimation of average blood sugar levels over several months. The higher the sugar level, the more attaches to hemoglobin, so a "normal" hemoglobin A1C (the test used to measure glycosylated hemoglobin) is between 4.5 and 6 percent. The red blood cell lives for about 110 days, so, with these test results, we can estimate sugar levels in the preceding two or three months. We'd like to be able to achieve a "normal" (equivalent to a non-diabetic) glycosylated hemoglobin level in all persons with diabetes, but the risk of hypoglycemia is sometimes too great. We try to achieve an A1C of 7, since in many studies, including the landmark Diabetes Control and Complications Trial (DCCT), a 7 percent level greatly decreased the number of persons with diabetes who developed complications, as compared with the 9 percent (A1C results) average found in less aggressively treated groups. No measurement of reversibility was undertaken in these studies.
It is true that in persons with diabetic complications, reduction of sugar level (and therefore also hemoglobin A1C) reduced the progression of complications. There are a few reports that improvement in sugar control improved nerve function, and very early eye changes may show some improvement. Perhaps that is what your diabetes educator is alluding to? The problem is, however, that over time, complications can cause scarring or blood vessel changes, and such tissue destruction does not reverse.
Advanced Glycosylation Endproducts (AGEs) are formed from glycosylated proteins, and do not change as rapidly as other proteins. These materials seem to be important in the persistence of many diabetic complications.
You should not surrender to diabetes, even if you have complications, since
you can slow or stop the progression of these problems by controlling blood
sugar as carefully as possible and leading a healthy life.