Aldose reductase inhibitors are a class of drugs being studied as a way to prevent eye and nerve damage in people with diabetes.
Their target, aldose reductase, is an enzyme that is normally present in many other parts of the body, and catalyzes one of the steps in the sorbitol (polyol) pathway that is responsible for fructose formation from glucose.
Aldose reductase activity increases as the glucose concentration rises in diabetes in those tissues that are not insulin sensitive, which include the lenses, peripheral nerves, and glomerulus.
Sorbitol does not diffuse through cell membranes easily and therefore accumulates, causing osmotic damage which leads to retinopathy and neuropathy.
[7] This class of drugs is also under investigation as a possible root pathology modulating treatment for asthma and COPD since it has been shown that they inhibit goblet cell metaplasia in the respiratory epithelium, thereby reducing the copious mucous secretion associated with these.