Enzymatic Spirulina Extract Enhances the Vasodilation in Aorta and Mesenteric Arteries of Aged Rats

Aging, one of the main factors associated with cardiovascular diseases, induces vascular modifications through nitric oxide (NO) release and oxidative stress. Based on the antioxidant properties of the non-enzymatic spirulina extract (non-Enz-Spir-E) and that degrading enzymes enhances the extract bioactivity, the aim of this study was to analyze the in vitro effect of an Alcalase-assisted Enz-Spir-E on the vasodilator function of conduit and resistance arteries (which differently contribute to blood pressure regulation) in aging. Therefore, thoracic aorta (TA) and mesenteric arteries (MA) from male Sprague-Dawley rats (20-22 months-old) were divided into two groups: non-incubated vessels and vessels exposed to Enz-Spir-E (0.1% w/v) for 3 h. The vasodilation to acetylcholine (ACh), sodium nitroprusside (SNP, a NO donor), carbon-monoxide-releasing molecule (CORM), and cromakalim (a potassium channel opener), as well as NO and superoxide anion production, were studied. Enz-Spir-E increased the ACh-, SNP-, and CORM-induced responses in both types of arteries, while the cromalakim-induced relaxation was increased only in MA. Enz-Spir-E increased NO release (TA: 5.69-fold; MA: 1.79-fold), while it reduced superoxide anion formation (TA: 0.52-fold; MA: 0.66-fold). These results indicate that Enz-Spir-E improves aging-associated vasodilation through increasing NO release/bioavailability in both types of arteries and hyperpolarizing mechanisms only in MA.