Source: Diabetologia  |  Posted 9 years ago

Nitric oxide has an altered metabolic fate in patients with type 1 diabetes mellitus, which could affect microvascular regulation and tissue perfusion.

Glycosylation appears to affect the nitric oxide binding affinity of haemoglobin and plasma proteins, leading to reduced nitric oxide availability and altered nitric oxide metabolism in type 1 diabetics.

Changes include preferential metabolism of nitric oxide to nitrosyl haemoglobin and nitrosothiols, according to investigators.

The investigators, from Wales Heart Research Institute at the University of Wales College of Medicine in Heath Park, Cardiff, England, studied nitric oxide binding to haemoglobin and nitrate, nitrite, nitrosyl haemoglobin and plasma nitrosothiols in 23 patients with uncomplicated type 1 diabetes mellitus and 17 non-diabetic controls.

Results showed increased nitric oxide-haemoglobin binding when glycosylated haemoglobin level was greater than 8.5 percent compared with 5.9 per cent.

Diabetic patients had higher basal nitrosyl haemoglobin compared with controls. Basal plasma nitrosothiol, nitrate and nitrite levels were similar between patients and controls.

When nitric oxide was added to blood samples []ex vivo[], it was preferentially metabolized to nitrosyl haemoglobin and plasma nitrosothiols in diabetic patients. These changes were positively correlated with levels of glycosylated haemoglobin.

Such alterations in nitric oxide metabolism could be involved in diabetic macrovascular and microvascular disease, according to the investigators.