Reactive oxygen and nitrogen species in pathogenesis of vascular complications of diabetes

Abstract

Macrovascular and microvascular diseases are currently the principal causes of morbidity and mortality in subjects with diabetes. Disorders of the physiological signaling functions of reactive oxygen species (superoxide and hydrogen peroxide) and reactive nitrogen species (nitric oxide and peroxynitrite) are important features of diabetes. In the absence of an appropriate compensation by the endogenous antioxidant defense network, increased oxidative stress leads to the activation of stress-sensitive intracellular signaling pathways and the formation of gene products that cause cellular damage and contribute to the vascular complications of diabetes. It has recently been suggested that diabetic subjects with vascular complications may have a defective cellular antioxidant response against the oxidative stress generated by hyperglycemia. This raises the concept that antioxidant therapy may be of great benefit to these subjects. Although our understanding of how hyperglycemia-induced oxidative stress ultimately leads to tissue damage has advanced considerably in recent years, effective therapeutic strategies to prevent or delay the development of this damage remain limited. Thus, further investigation of therapeutic interventions to prevent or delay the progression of diabetic vascular complications is needed.

Keywords: Diabetic vascular complications; Reactive nitrogen species; Reactive oxygen species.

Fig. 1

Induction of reactive oxygen species (ROS)/reactive nitrogen species (RNS) formation by hyperglycemia in diabetes. The major enzymes responsible for ROS generation in the vasculature include NAD(P)H oxidase, xanthine oxidase, and uncoupled nitric oxide synthase (NOS). The absence of an appropriate compensation by the endogenous antioxidant defense network and increased oxidative stress leads to the activation of stress-sensitive intracellular signaling pathways and the formation of gene products that cause cellular damage and contribute to the late complications of diabetes. AGE, advanced glycation end-products; PKC, protein kinase C; SOD, superoxide dismutase; GSH, reduced glutathione; GSSG, oxidized glutathione.