Diabetes-induced vascular dysfunction involves arginase I.

Area of Science:

• Cardiovascular Biology
• Metabolic Disease Research
• Vascular Physiology

Background:

• Arginase contributes to vascular dysfunction by depleting l-arginine and promoting fibrosis.
• Increased arginase expression and activity are linked to endothelial cell dysfunction.
• The distinct roles of arginase isoforms I and II in diabetes-induced vascular damage require further investigation.

Purpose of the Study:

• To investigate the specific roles of arginase I and arginase II in diabetes-associated vascular dysfunction.
• To determine the impact of arginase isoform deficiency on endothelial cell function, vascular fibrosis, and stiffness in a diabetic mouse model.

Main Methods:

• Utilized streptozotocin-induced diabetic mice, including wild-type, arginase II knockout, and combined partial arginase I/II knockout models.
• Assessed endothelial cell-dependent vasorelaxation in aortic rings.
• Quantified arterial fibrosis and stiffness, alongside arginase activity and expression levels.

Main Results:

• Diabetic wild-type and arginase II knockout mice showed significantly reduced vasorelaxation and increased coronary fibrosis and carotid stiffness compared to controls.
• Mice with partial deletion of arginase I (AI(+/-)AII(-/-)) exhibited preserved endothelial cell-dependent vasodilation and reduced vascular fibrosis and stiffness.
• Aortic arginase activity and arginase I expression were elevated in diabetic wild-type and arginase II knockout mice but not in the partial arginase I knockout group.

Conclusions:

• Arginase I plays a critical role in mediating diabetes-induced vascular endothelial cell dysfunction, fibrosis, and stiffness.
• Partial deficiency of arginase I significantly ameliorates diabetes-related vascular complications.
• Targeting arginase I presents a potential therapeutic strategy for managing vascular dysfunction in diabetes.