Effects of Chitosan Source on the Modulation of Vascular Tone

Uncontrolled bleeding is a preventable cause of death in trauma injuries and surgery; therefore, controlling severe bleeding is crucial. Chitosan is a material used to develop haemostatic products owing to its haemostatic properties and non-toxicity. Described chitosan haemostatic mechanisms involve electrostatic interactions with negatively charged red blood cell membranes, promoting red blood cell agglutination and platelet activation and aggregation. However, chitosan modulation of vascular tone remains underexplored. In this work, the vascular response of two low-molecular-weight chitosan samples (crustacean and squid pen) is evaluated. UV-Vis, FTIR, GPC, and MALDI-TOF were used to characterise the chitosan samples. Vascular responses were assessed in isolated rat aortic rings mounted in an organ bath. Chitosan alone did not induce vasoconstriction. However, both chitosan samples increased vascular responsiveness by potentiating Phenylephrine (PE)-induced contraction and reducing acetylcholine-mediated vasorelaxation. The chitosan monomers also enhanced PE-induced contraction, with glucosamine producing a stronger effect than N-acetylglucosamine. These findings identify a vasoactive effect of chitosan on vascular responsiveness. This property may be relevant to haemostatic performance and supports further development of chitosan-based haemostatic formulations, while the underlying mechanisms require direct investigation in future studies.