Liraglutide treatment attenuates dysfunction-related changes in the cardiac and cerebral microvasculature in streptozotocin-induced diabetic rats

Type of funding sources: Foundation. Main funding source(s): Novo Nordisk

Diabetes mellitus (DM) induces cardiac and cerebral microvascular dysfunction via increased glycation, oxidative stress and endothelial activation. Liraglutide, a glucagon-like peptide-1 receptor analogue, inhibited the reactive oxygen species producing enzyme NOX2 and adhesion molecules in isolated endothelial cells. Here we have studied how Liraglutide affects advanced glycation, NOX expression and inflammatory status of the cardiac and cerebral microvasculature in vivo in diabetic rats.

DM was induced in Sprague Dawley rats (n=15) via intraperitoneal streptozotocin (STZ) injection (60 mg/kg body weight). 10 control rats remained non-diabetic. From day 9 post-STZ injection, Liraglutide (200 µg/kg bodyweight; n=7) or vehicle (n=8) was injected subcutaneously daily until termination on day 29. The advanced glycation end-product N-ε-(carboxymethyl)lysine (CML), NOX2, NOX4, ICAM-1 and VCAM-1 were subsequently analysed using immunohistochemistry and quantified to compare Liraglutide treatment to placebo.

DM increased CML, NOX2, ICAM-1 and VCAM-1 in the intramyocardial vasculature, although not significant for NOX2. NOX4 was not significantly increased in the ventricles and absent in the atria. In the cerebral vasculature, CML, NOX2 and NOX4 were significantly increased, but not ICAM-1 and VCAM-1. Liraglutide significantly reduced the DM-associated CML accumulation and expression of NOX2, ICAM-1 and VCAM-1 in the intramyocardial, and CML, NOX2 and NOX4 in the cerebral vasculature. Liraglutide had these effects without changing blood glucose levels or body weight.

Our study implies that Liraglutide protects the cardiac and cerebral microvasculature against diabetes-induced dysfunction, independent of a blood glucose lowering effect in a type 1 diabetes rat model.