an-vitro-model-parallel-plate-perfusion-system-to-study-bacterial

An <em>In Vitro</em> Model of a Parallel-Plate Perfusion System to Study Bacterial Adherence to Graft Tissues

Various valved conduits and stent-mounted valves are used for right ventricular outflow tract (RVOT) valve replacement in patients with congenital heart ...

RWTH Aachen University

Cardiovascular diseases represent the most common cause of morbidity and mortality worldwide. In this review, we explore the potential of bioengineered vascular constructs as living models for in vitro cardiovascular research to advance the current knowledge of pathophysiological processes and support the development of clinical therapies. Bioengineered vascular constructs capable of recapitulating the cellular and mechanical environment of native vessels represent a valuable platform to study cellular interactions and signaling cascades, test drugs and medical devices under (patho)physiological conditions, with the additional potential benefit of reducing the number of animals required for preclinical testing.

Bioengineered vascular constructs as living models for in vitro cardiovascular research.

Currently, there is no optimal treatment available for end stage tumour patients with airway stenosis. The PulmoStent concept aims on overcoming current hurdles in airway stenting by combining a nitinol stent with a nutrient-permeable membrane, which prevents tumour ingrowth. Respiratory epithelial cells can be seeded onto the cover to restore mucociliary clearance. In this study, a novel hand-braided dog bone stent was developed, covered with a polycarbonate urethane nonwoven and mechanically tested. Design and manufacturing of stent and cover were improved in an iterative process according to predefined requirements for permeability and mechanical properties and finally tested in a proof of concept animal study in sheep for up to 24 weeks. In each animal two stents were implanted, one of which was cell-seeded by endoscopic spraying in situ. We demonstrated the suitability of this membrane for our concept by glucose transport testing and in vitro culture of respiratory epithelial cells. In the animal study, no migration occurred in any of the twelve stents. There was only mild granulation tissue formation and tissue reaction; no severe mucus plugging was observed. Thus, the PulmoStent concept might be a step forward for palliative treatment of airway stenosis with a biohybrid stent device.

PulmoStent: In Vitro to In Vivo Evaluation of a Tissue Engineered Endobronchial Stent.

Endovascular treatment using bare metal stents or drug eluting stents is routinely performed to restore the blood flow in the coronary and peripheral arteries; however, intimal hyperplasia and late stent thrombosis are still major issues leading to stent failure and often to the need for re-intervention. Covered stents have emerged as an alternative approach to avoid intimal hyperplasia. They are characterized by the presence of a membrane that spans the struts of the stent and acts as a physical barrier to block the ingrowth of the neointimal tissue into the lumen. Currently used membrane-materials include mainly synthetic polymers. Their main limitation is their lack of hemocompatibility, which can induce thrombosis and ultimately reocclusion, thus impairing the long-term performance of these devices. To overcome this issue, the use of biologically-derived materials has been proposed with the aim of enhancing the biocompatibility and the capability of this type of stents to support endothelialization. The aim of this review is to give a comprehensive overview of the applications of bio-based covered stents as well as the different strategies followed for their development from the perspective of the material selection, fabrication approaches and validation of the different concepts in animal and clinical trials.

Article	Year
Bioengineered vascular constructs as living models for in vitro cardiovascular research. Drug discovery today\| PubMed ID: 27126777	2016
PulmoStent: In Vitro to In Vivo Evaluation of a Tissue Engineered Endobronchial Stent. Annals of biomedical engineering\| PubMed ID: 27679445	2017
Bio-based covered stents: the potential of biologically-derived membranes. Tissue engineering. Part B, Reviews\| PubMed ID: 30311858	2018

Stefan Jockenhoevel

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