ABSTRACT
Diabetes mellitus and impaired glucose tolerance are linked to increased cardiovascular
morbidity and mortality. Vascular disease is directly associated with plasma glucose
levels, and reduction of these levels forestalls to a certain extent the vascular
complications of diabetes, such as myocardial infarction, nephropathies, and retinopathies.
In addition to hyperglycemia, there are other risk factors that play a prominent role,
such as hypertension, hyperlipidemia, and genetic factors. Endothelial dysfunction
is one of the major factors in the development of cardiovascular disease. The vascular
endothelium regulates the blood flow by tightly controlling the coagulation system,
cell-cell interaction, and vascular tone. These functions are disturbed in diabetic
patients. In diabetics, endothelin-1 levels are increased, leading to vasoconstriction.
Endothelin levels are directly related to plasma glucose levels. In addition, the
endothelial cell-NO axis is disturbed. NO release and function are impaired. This
seems to be dependent upon hyperglycemia and genetic factors. Impaired NO function
also results in vasoconstriction. Furthermore, enhanced vascular permeability is seen
in diabetics. This appears to be related to impaired endothelial cell relaxation and
reactive oxygen species as well as advanced glycosylated end products (AGEs). The
complex changes seen in diabetes and even prediabetes are therefore related to numerous
derailments related to endothelial dysfunction, and no single therapeutic approach
is likely to solve the problem of vascular complications.
KEYWORD
Diabetes - endothelium - hyperglycemia - vascular permeability - cardiovascular disease
