Local elasticity imaging of vascular tissues using a tactile mapping system

This study aimed to map the elasticity of a natural artery at the micron level by using a tactile mapping system (TMS) that was recently developed for characterization of the stiffness of tissue slices. The sample used was a circumferential section (thickness, approximately 1 mm) of a small-caliber porcine artery (diameter, approximately 3 mm). Elasticity was measured with a probe of diameter 1 μm and a spatial resolution of 2 μm at a rate of 0.3 s per point, without significant sample invasion. Topographical measurements were also performed simultaneously. Wavy regions of high elasticity, layered in the circumferential direction, were measured at the tunica media, which was identified as an elastin-rich region. The Young’s modulus of the elastin-rich region in the media was 50.8 ± 13.8 kPa, and that of the elastin-rich region of the lamina elastica interna was 69.0 ± 12.8 kPa. Both these values were higher than the Young’s modulus of the other regions in the media, including smooth muscle cells and collagen fibrils (17.0 ± 9.0 kPa). TMS is simple and inexpensive to perform and allows observation of the distribution of the surface elastic modulus at the extracellular matrix level in vascular tissue. TMS is expected to be a powerful tool in evaluation of the maturation and degree of reconstruction in the development of tissue-engineered or artificial tissues and organs.