von Willebrand factor and its propeptide in children with diabetes. Relation between endothelial dysfunction and microalbuminuria.

It has been shown that patients with insulin-dependent diabetes mellitus have elevated von Willebrand factor (vWF) plasma concentrations. Plasma fibrinogen, vWF, and its propeptide concentrations have been evaluated in 102 children with insulin-dependent diabetes mellitus to determine whether an increase of vWF and its propeptide levels precedes and may predict the development of persistent microalbuminuria. The patients have been divided into two groups according to the presence or absence of microalbuminuria at the end of follow-up. They have been followed up for at least 8 y. Control group consisted of 80 age- and sex-matched healthy volunteers. At the beginning of the study there was no significant difference in fibrinogen, vWF, and its propeptide levels between patients and control subjects. During the follow-up, a significant increase of plasma vWF and its propeptide has been observed in the group of patients who later developed microalbuminuria but not in those who remained normoalbuminuric. This increase started 3 y and become statistically significant (p < 0.01) 2 y before the onset of microalbuminuria, persisting until the end of the study. During the entire follow-up plasma values of fibrinogen persisted in the normal range. In conclusion, an increase in plasma concentration of vWF and its propeptide precedes microalbuminuria and, therefore, can be useful to identify children with insulin-dependent diabetes mellitus at risk to develop incipient nephropathy later in life.