title: Full Mimicking of Coronary Hemodynamics for Ex-Vivo Stimulation of Human Saphenous Veins.
abstract: After coronary artery bypass grafting, structural modifications of the saphenous vein wall lead to lumen narrowing in response to the altered hemodynamic conditions. Here we present the design of a novel ex vivo culture system conceived for mimicking central coronary artery hemodynamics, and we report the results of biomechanical stimulation experiments using human saphenous vein samples. The novel pulsatile system used an aortic-like pressure for forcing a time-dependent coronary-like resistance to obtain the corresponding coronary-like flow rate. The obtained pulsatile pressures and flow rates (diastolic/systolic: 80/120 mmHg and 200/100 mL/min, respectively) showed a reliable mimicking of the complex coronary hemodynamic environment. Saphenous vein segments from patients undergoing coronary artery bypass grafting (n = 12) were subjected to stimulation in our bioreactor with coronary pulsatile pressure/flow patterns or with venous-like perfusion. After 7-day stimulation, SVs were fixed and stained for morphometric evaluation and immunofluorescence. Results were compared with untreated segments of the same veins. Morphometric and immunofluorescence analysis revealed that 7 days of pulsatile stimulation: (i) did not affect integrity of the vessel wall and lumen perimeter, (ii) significantly decreased both intima and media thickness, (iii) led to partial endothelial denudation, and (iv) induced apoptosis in the vessel wall. These data are consistent with the early vessel remodeling events involved in venous bypass adaptation to arterial flow/pressure patterns. The pulsatile system proved to be a suitable device to identify ex vivo mechanical cues leading to graft adaptation.
authors.affiliation: Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, P.zza Leonardo da Vinci 32, 20133, Milan, Italy. marco.piola@polimi.it.
authors.forename: Marco
authors.identifier: 0000-0002-4501-2385
authors.initials: M
authors.lastname: Piola
authors.affiliation: Unità di Ingegneria Tissutale, Centro Cardiologico Monzino-IRCCS, Via Parea 4, 20138, Milan, Italy.
authors.forename: Matthijs
authors.initials: M
authors.lastname: Ruiter
authors.affiliation: Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, P.zza Leonardo da Vinci 32, 20133, Milan, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Vismara
authors.affiliation: Unità di Ingegneria Tissutale, Centro Cardiologico Monzino-IRCCS, Via Parea 4, 20138, Milan, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Mastrullo
authors.affiliation: Dipartimento di Scienze Cliniche e di Comunità, Università di Milano, Via Parea 4, 20138, Milan, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Agrifoglio
authors.affiliation: Divisione di Cardiochirurgia, Centro Cardiologico Monzino-IRCCS, Via Parea 4, 20138, Milan, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Zanobini
authors.affiliation: Unità di Ingegneria Tissutale, Centro Cardiologico Monzino-IRCCS, Via Parea 4, 20138, Milan, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Pesce
authors.affiliation: Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, P.zza Leonardo da Vinci 32, 20133, Milan, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Soncini
authors.affiliation: Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, P.zza Leonardo da Vinci 32, 20133, Milan, Italy.
authors.forename: Gianfranco Beniamino
authors.initials: GB
authors.lastname: Fiore
mesh_terms: D001026:Coronary Artery Bypass; D003326:Coronary Circulation; D006801:Humans; D008955:Models, Cardiovascular; D011673:Pulsatile Flow; D012501:Saphenous Vein / Q000503:physiopathology*
keywords: Coronary flow rate; Ex vivo platform; Pulsatile pressure; Saphenous vein graft disease; Wall remodeling