DbCM can occur in both Type 1 and Type 2 diabetics, despite glucose control. When there is too much glucose in the body, it is broken down by the polyol pathway. The polyol pathway is a specific chemical reaction that converts glucose into other substances. The first enzyme in this pathway is Aldose Reductase, which converts glucose to a substance called sorbitol and (eventually) fructose, another type of sugar.

Sorbitol and fructose can damage the heart in many ways. One example is something called oxidative stress. As the name suggests, oxidative stress causes a lot of stress to the heart because of an increase in molecules, called free radicals, that are harmful to important structures in cells. When these structures are harmed, the cells in the heart cannot do their job properly. Aldose Reductase activation also detracts glucose from the energy efficient hexokinase/glycolytic pathway, resulting in less energy production for cardiomyocytes.

Sorbitol and fructose will eventually cause cell death if they are not controlled. The damage that occurs includes heart fibrosis, or “hardening” of the heart. When this happens, the heart becomes less effective at pumping blood to the rest of the body.

If DbCM is not treated, it can become worse, progressing to overt heart failure and potentially death. A specific treatment for DbCM is needed.