Research of smooth muscle cells response to fluid flow shear stress by hyaluronic acid micro-pattern on a titanium surface

The morphology of vascular smooth muscle cells (SMCs) in the normal physiological state depends on cytoskeletal distribution and topology beneath, and presents vertical to the direction of blood flow shear stress (FFSS) although SMCs physiologically are not directly exposed to the shear conditions of blood flow. However, this condition is relevant for arteriosclerotic plaques and the sites of a vascular stent, and little of this condition in vitro has been studied and reported till now. It is unclear what will happen to SMC morphology, phenotype and function when the direction of the blood flow changed. In this paper, the distribution of SMCs in a specific area on Ti surface was regulated by micro-strips of hyaluronic acid (HA). Cell morphology depended on the distribution of the cytoskeleton extending along the micrographic direction. Simulated vascular FFSS was perpendicular or parallel to the direction of the cytoskeleton distribution. Based on investigating the morphology, apoptotic number, phenotypes and functional factors of SMCs, it was obtained that SMCs of vertical groups showed more apoptosis, expressed more contractile types and secreted less TGF-β1 factor compared with SMCs of parallel groups, the number of ECs cultured by medium from SMCs of parallel groups was larger than vertical groups. This study could help to understand the effect of direction change of FFSS on patterned SMC morphology, phenotype and function. A controllable FFSS and topology system for SMCs mimicking human blood vessels was built in vitro, and was used to investigate the effect of FFSS with different directions on the patterned SMCs which were the major component of the vascular middle membrane, but also the culprit of atherosclerosis, due to distinct cell phenotypes. [Display omitted] •Vertical FFSS contributed to more apoptotic SMCs compared with parallel FFSS on the TiOH/HAP.•Vertical FFSS led to larger orientation angles of SMCs, while parallel FFSS led to larger L/B index.•SMCs of vertical groups express more contractile types compared with SMCs of parallel groups•SMCs of parallel groups secreted more TGF-β1 factor compared with SMCs of vertical groups.•The number of ECs cultured by medium from SMCs of parallel groups was larger than vertical groups.