arkOn October 2, 2013, Joris van Ark, defended his thesis titled:

Role of circulating vascular progenitor cells in the development of macrovascular disease in diabetes.

Promotores were Prof. dr. J.L. Hillebrand and Prof. dr. B.H.R. Wolffenbuttel.

Joris  studied the role of vascular progenitor cells in diabetes. Cardiovascular diseases are the number one cause of death in industrialised countries. Macrovascular disease (MVD) contributes to this to a considerable extent. Type 2 diabetes is associated with a 2- to 4-fold increase in rates of MVD. The underlying causes of the accelerated progression of MVD in diabetes are incompletely understood. Therefore, new insights into the mechanisms behind the development of MVD are essential to develop effective therapies for the prevention and treatment of MVD in patients with diabetes. Circulating vascular progenitor cells (VPCs) contribute to the health and maintenance of blood vessels. Different types of VPCs are described which have different effects on the development of MVD. Endothelial progenitor cells (EPCs) and circulating angiogenic cells (CACs) inhibit the progression of MVD. On the other hand, smooth muscle progenitor cells (SMPCs) are able to stimulate the progression of MVD. In this thesis we investigated the role of circulating VPCs in the development of MVD in patients with type 2 diabetes. We demonstrate that the number of protective EPCs and CACs is decreased in the blood of diabetic patients. In contrast, the number of damaging SMPCs is slightly increased in these patients. Therefore, the balance between protective and damaging VPCs is disturbed in favour of the latter. This may contribute to the accelerated development of MVD in patients with diabetes. This makes VPCs a potential therapeutic target to inhibit the progression and prevent the complications of MVD in patients with type 2 diabetes.