Endothelial Adhesion Molecules in Diabetes - Adhesion Molecules - page 185

ADHESION MOLECULES AND RISK OF TYPE 2
DIABETES

Pinkney et al. (1997) i rst put forth the hypothesis that endothelial dysfunction
is a common antecedent of the insulin resistance/metabolic syndrome and
is intrinsically related to many of its key clinical features. Several biological
mechanisms have subsequently been proposed to explain the complex and
reciprocal relationships between endothelial dysfunction and insulin resistance
(shown in Fig. 1) . Briel y, endothelial dysfunction could directly promote the
development and progression of insulin resistance. Alternatively, impaired insulin
action may also directly exacerbate endothelial dysfunction. Several studies in
non-diabetic individuals have suggested that mildly impaired fasting glucose
levels (though within the normoglycemic range) accelerate the impairment of
endothelial function via adverse ef ects on oxidative stress, formation of advanced
glycation end products, and elevated levels of free fatty acids (Pinkney et al. 1997,
Kim et al. 2006).

Systemic inflammation

↑ Dyslipidemia

Non-diabetic
hyperglycemia

↑ Blood pressure

↓ Fibrinolysis

Endothelial dysfunction

↑ Coagulation

Oxidative stress

↑ Platelet aggregation

Insulin resistance b -cell dysfunction

Type 2 Diabetes and Atherosclerotic CVD

Fig. 1 Diagram of the 'common soil' hypothesis for reciprocal relationships between endothelial
dysfunction and insulin resistance and other metabolic disorders for the pathogenesis of type 2
diabetes and atherosclerotic cardiovascular disease.

A number of cross-sectional studies in non-diabetic individuals have shown a
strong positive relationship between levels of E-selectin, ICAM-1, and VCAM-1
and insulin resistance and/or glucose intolerance (Pinkney et al. 1997, Schram and
Stehouwer 2005). However, the cross-sectional evidence does not prove causality.
Endothelial dysfunction characterizes all phases of insulin resistance and its
related metabolic abnormalities, lending support to the 'common soil' hypothesis
that endothelial dysfunction, as rel ected by elevated levels of soluble endothelial
adhesion molecules, may be one of the common antecedents for the pathogenesis