**9. Conclusion**

Viscoelastic properties of the skin can be measured by various methods and are dependent on the connective tissue architecture formed by ECM molecules. In order to measure the actual viscoelasticity of the skin, we have developed a novel device that can monitor the external forces on the skin in real time. The device can be used for treatment and prevention of pressure ulcers that are affected by viscoelasticity and external force. Among the ECM molecules, versican—a chondroitin sulfate proteoglycan—is an important ECM molecule for viscoelasticity because it constitutes the fibrillin-versican-hyaluronan network. In human pathogenic conditions such as solar elastosis, loss of viscoelastic properties of the dermis is found to occur because of the loss of hyaluronan-binding versican. Marfan syndrome—a genetic connective tissue disease—is also characterized by loss of viscoelasticity in elastic tissues, such as those in the aorta. Finally, aging-associated loss of viscoelasticity and stiffness of connective tissue are proposed to be the common pathogenesis of Tarumi disease.
