La Microangiopathy Diabetique

Summary

Diabetic microangiopathy is morphologically defined as a thickening of the basement membrane of the capillaries. Its clinical manifestations are essentially the retinopathy (the four evolutionary stages of which are described) and the glomerular nephropathy, extending from the diffuse type to the classical nodular one.

Various etiopathogenic hypotheses have been proposed, the most important of which are:

1) The diabetic erythrocytes deliver less easily oxygen to the tissues; this is due to a deficiency in organic phosphate compounds (mainly diphosphoglycerate) regulating the hemoglobin dissociation curve, and to an abnormal accumulation of the dysfunctional glycosylated hemoglobin Ale.

2) The diabetic endothelial cell may suffer from an excessive sorbitol accumulation and from inositol (which is a growth factor) deficiency.

3) Basement membrane of diabetics is chemically and functionally altered, paritcularly in its glycoprotein component.

Prolonged hyperglycemia in itself can explain these three alterations. Consequently, the major aim of the treatment of diabetes is to prevent the development of the microangiopathy by ensuring continuously an optimal blood glucose control.