Tissue engineering of blood vessels: characterization of smooth‐muscle cells for culturing on collagen‐and‐elastin‐based scaffolds

Abstract

Tissue engineering offers the opportunity to develop vascular scaffolds that mimic the morphology of natural arteries. We have developed a porous three-dimensional scaffold consisting of fibres of collagen and elastin interspersed together. Scaffolds were obtained by freeze-drying a suspension of insoluble type I collagen and insoluble elastin. In order to improve the stability of the obtained matrices, they were cross-linked by two different methods. A water-soluble carbodi-imide, alone or in combination with a diamine, was used for this purpose: zero- or non-zero-length cross-links were obtained. The occurrence of cross-linking was verified by monitoring the thermal behaviour and the free-amino-group contents of the scaffolds before and after cross-linking. Smooth-muscle cells (SMCs) were cultured for different periods of time and their ability to grow and proliferate was investigated. SMCs were isolated from human umbilical and saphenous veins, and the purity of the cultures obtained was verified by staining with a specific monoclonal antibody (mAb). Cultured cells were also identified by mAbs against muscle actin and vimentin. After 14 days, a confluent layer of SMCs was obtained on non-cross-linked scaffolds. As for the cross-linked samples, no differences in cell attachment and proliferation were observed between scaffolds cross-linked using the two different methods. Cells cultured on the scaffolds were identified with an anti-(alpha-smooth-muscle actin) mAb. The orientation of SMCs resembled that of the fibres of collagen and elastin. In this way, it may be possible to develop tubular porous scaffolds resembling the morphological characteristics of native blood vessels.

Elastin as a biomaterial for tissue engineering

“…Another method to prepare tubular scaffolds is by pouring a diluted acetic acid suspension of purifi ed type I collagen fi brils and elastin fi bres in a tubular mould, freezing at -18°C and lyophilising. In static culture as well as under pulsatile fl ow, smooth muscle cells were able to adhere to and proliferate in these porous 3D collagenelastin tubes for up to 14 days while maintaining their contractile phenotype as evidenced from smooth muscle actin staining [207][208][209]. Tubes may also be prepared by winding of a sheet, as was performed with recombinant tropoelastin [124].…”

Structural hierarchy of biomimetic materials for tissue engineered vascular and orthopedic grafts

“…Elastin has been introduced in collagen/elastin based tissue engineered vascular grafts [20] either in gel-derived fibrous products [21] or electrospun micro-and nano-fibrous scaffolds [22,23]. Apart from the purpose of mimicking the artery composition, elastin has been reported to improve the mechanical properties of collagen/elastin scaffolds which would have been too weak to be implanted as vascular grafts if they were based only on collagen [24].…”

Electrospinning jets and nanofibrous structures

“…As collagen and elastin are two of the most predominant proteins in the native vessel, they are often used together as tissue engineering scaffolds for vascular scaffolds, with or without synthetic polymers. 39,52,57,93,175,176 Elastin has also been blended with PLA for urologic tissue engineering. 177 Recently, silk fibroin ͑SF͒ has gained immense popularity in the field of tissue engineering.…”