Effects of various monomers and micro-structure of polyhydroxyalkanoates on the behavior of endothelial progenitor cells and endothelial cells for vascular tissue engineering

Cardiovascular diseases are a leading cause of mortality in the world today. Vascular tissue engineering is an important and attractive research issue for the repair and regeneration of blood vessels. Two bio-based polymers, poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), which both belong to the polyhydroxyalkanoate (PHA) family, were used in this study. The aim of this study is to assess the potential application of PHB and PHBV to serve as a scaffold that is seeded with human umbilical vein endothelial cells (HUVECs) or endothelial progenitor cells (EPCs) for vascular tissue engineering. PHA films with various surface characteristics were prepared by solution-casting (surface roughness) and electrospinning (mesh-like structure). First, the mechanical and physical properties of various types of PHA films were analyzed. Then, the PHAs films were examined for cytotoxicity, biocompatibility and proliferation ability using cell lines (3 T3 and L929) and primary cells (HUVECs and EPCs). The cell morphology cultured on the PHA films was observed by fluorescence microscope and scanning electron microscopy. In addition, cultured EPCs on various types of PHA films were analyzed for whether the cells maintained the abilities of Ac-LDL uptake and UEA-1 lectin binding and exhibited specific gene expressions, including VEGFR-2, vWF, CD31, CD34 and CD133. Importantly, the cell retention rate and anticoagulation ability of HUVECs or EPCs cultured on the various types of PHA films were also evaluated at the indicated time points. Our results showed that PHA films that were prepared using electrospinning methods (Ele-PHB and Ele-PHBV) had good mechanical and physical properties. HUVECs and EPCs can attach and grow on Ele-PHB and Ele-PHBV films without showing cytotoxicity. After a one-week culture, expanded HUVECs or EPCs maintained the correct cell morphologies and exhibited correct cell functions, such as high cell attachment rate and anti-coagulation ability. Taken together, Ele-PHB and Ele-PHBV films were ideal bio-based polymers to combine with HUVECs or EPCs for vascular tissue engineering.