Sepiapterin Improves Vascular Reactivity and Insulin-Stimulated Glucose in Wistar Rats

Area of Science:

• Cardiovascular Physiology
• Mitochondrial Biology
• Pharmacology

Background:

• Sedentary behavior induces endothelial dysfunction, increasing cardiovascular disease risk.
• Endothelial nitric oxide synthase (eNOS) dysfunction and altered mitochondrial function are key features.
• Sepiapterin, a precursor to the eNOS cofactor tetrahydrobiopterin (BH4), may offer a therapeutic strategy.

Purpose of the Study:

• To investigate if sepiapterin supplementation improves endothelium-dependent vasodilation and insulin sensitivity in sedentary rats.
• To determine the effects of sepiapterin on eNOS function and mitochondrial respiration in the vasculature.

Main Methods:

• Sedentary male Wistar rats were supplemented with sepiapterin in their diet for 5 weeks.
• Insulin and glucose tolerance tests were performed at baseline and endpoint.
• Aortic vasoreactivity and mitochondrial respiration were assessed.

Main Results:

• Sepiapterin treatment significantly improved insulin tolerance.
• ACh-induced vasodilation in aortic tissues was significantly enhanced in sepiapterin-treated rats.
• Sepiapterin increased state 3 and state 4 mitochondrial respiration but lowered the respiratory control ratio.

Conclusions:

• Sepiapterin supplementation effectively improves vascular relaxation and insulin sensitivity in sedentary animals.
• The benefits are linked to the modulation of nitric oxide synthase (NOS) function and mitochondrial activity.
• Targeting NOS pathways with sepiapterin presents a promising approach for mitigating sedentary behavior-induced vascular impairments.