Following the permanent implantation of a coronary stent, optimal arterial wall healing is characterised by re-endothelialisation, the regrowth of a functional Endothelial Cell (EC) monolayer over the exposed stent surface. However incomplete re-endothelialisation, increases the risk of stent thrombosis which can cause vessel narrowing to reoccur. Previous research has suggested that the stent itself could be used as an electrode and when combined with non-invasive impedance spectroscopy techniques monitor post stenting healing. This could then inform clinicians on cell regrowth without the need for invasive imaging techniques. This study investigated the feasibility of the concept using 3 in vitro models representing potential cellular regrowth scenarios: re-endothelialisation (ECs), smooth muscle cell (SMCs) proliferation and co-culture (ECs and SMCs). -- Primary porcine ECs and SMCs were seeded onto platinum black electrodes and a bespoke impedance spectroscopy system used to carry out automated measurements for time periods of up to 10 days. Endothelium function was assessed through the measurement of the impedance response of confluent EC monolayers to the addition of either a gap junction enhancer, dipyridamole, or an inhibitor (heptanol or carbenoxolone). -- The results show that confluent, stent surface comparable populations of SMCs, ECs and co-culture of both cell types gives rise to distinct impedance signatures, most evident in the reactance component of impedance. This provides a potential method of non-invasively characterising the two cell types. Gap junction inhibition of EC monolayers dose dependently reduced total impedance. Conversely dipyridamole’s enhancing effect on gap junction formation caused an increase in total impedance. These novel findings show the importance of intercellular gap junction communication in the maintenance of the endothelial barrier function. Overall, the results demonstrate the potential of impedance spectroscopy in characterising vascular healing and endothelium function and could, in the future, provide clinically useful information in the development of new stents.
| Date of Award | 28 Sept 2017 |
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| Original language | English |
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| Awarding Institution | - University Of Strathclyde
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| Sponsors | EPSRC (Engineering and Physical Sciences Research Council) |
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