Mechanical properties and structure of carotid arteries in mice lacking desmin

Objective: Our aim was to determine in desmin homozygous mutant mice the vi scoelastic properties, the mechanical strength and the structure of the car otid artery. Methods: To assess the viscoelastic properties of large arteri es, we have performed an in vivo analysis of the diameter-. and distensibil ity-pressure curves of the common carotid artery (CCA) in homozygous (Des - /-), heterozygous (Des +/-) and wild-type (Des +/+) mice. To evaluate the m echanical strength, we have measured the in vitro intraluminal pressure pro ducing the rupture of the carotid artery wall. The structure analysis of th e arterial wall was based on histology and electronic microscopy. Results: A lower distensibility and an increase of arterial wall viscosity were obse rved in Des -/- compared with Des +/+. Arterial thickness of Des -/- was si milar to those of Des +/+. without changes in elastin and collagen contents . Electron microscopy revealed that the perimeter of cellular fingerlike-pr ojections was smaller in Des -/-, indicating that the cells have lost part of their connections to the extracellular matrix. The rupture pressure was significantly lower in Des -/- (1500+/-200 mmHg) compared with Des +/+ (210 0+/-80 mmHg) indicating a lower mechanical strength of the vascular wall. N o significant difference was found between Des +/- and Des +/+. Conclusion: The desmin is essential to maintain proper viscoelastic properties, struct ure and mechanical strength of the vascular wall. (C) 2001 Elsevier Science B.V. All rights reserved.