A Novel Technique for Murine Ex Vivo Heart Perfusion and Cervical Transplantation
Presented During: Welcome Reception and Poster Competition | Sponsored by: TransMedics
University of Colorado, Anschutz Medical Center, Aurora, CO
Denver, CO
United States - Contact Me
Jack Zakrzewki is a third year resident at the University of Colorado Department of Surgery. He graduated from the University of Illinois Chicago College of Medicine. He has an interest in general cardiac surgery, aortic root disease, and cardiac and lung transplant.
Friday, September 20, 2024: 5:00 PM - 6:30 PM
Omni King Edward Hotel
Description
Objective: As the use of ex vivo heart perfusion (EVHP) continues to expand clinically, there are limited studies assessing the impact of perfusate composition and strategies. This limitation is partly due to the lack of clinically relevant, easily reproducible, and cost-effective models to examine the impact of EVHP on post-transplantation outcomes. Here, we present a novel murine EVHP and transplantation model that allows for rapid prototyping and testing of EVHP strategies.
Methods: 10-12 week-old (20-30 grams) wild type mice underwent heart procurement. Hearts were then attached to a temperature- and pressure-controlled ex vivo perfusion system constructed from commercially available laboratory equipment. Hearts were perfused with acellular, unoxygenated Krebs-Henseleit (KH) buffer at 4⁰C for 90 minutes. Control hearts were maintained on ice under cold static preservation (CSP) conditions. After the preservation period, the donor grafts were transplanted onto the cervical vessels of a recipient mouse using a modified vascular cuff technique: the donor aorta was attached to the recipient carotid artery, and the donor pulmonary artery was attached to the recipient external jugular vein. Hearts were then allowed to re-perfuse for 120 minutes prior to echocardiographic assessment of function. As the left ventricle is unloaded in this model, fractional shortening and fractional area change were used to assess function.
Results: Overall graft survival at 120 minutes after cervical heart transplantation was similar between EVHP (n=18) and CSP (n=15) groups (72% vs. 67%, p=0.6 via Log-rank testing) (figure). Echocardiography demonstrated EVHP hearts had significantly improved graft function compared to CSP hearts: Short axis fractional shortening change 24.8% vs. 14.1%, p=0.005; short axis fractional area change 26.0% vs. 17.9%, p=0.03.
Conclusions: Our novel murine EVHP and heart transplantation model provides similar animal and graft post-transplantation survival compared to standard graft cold static preservation. Graft assessment with echocardiography demonstrated superior function of EVHP treated hearts compared to CSP controls. This model provides a new way to rapidly prototype various EVHP strategies, perfusate formulations, and techniques in a reproducible and cost-effective murine model. This approach can serve as a proof-of-concept testing platform before advancing to larger animal models. Cervical transplantation facilitates dynamic graft assessment via echocardiography in short-term survival models. Additionally, the success rate of the modified cervical cuff anastomosis technique allows for the consistent study of mechanisms of post-transplant graft failure, minimizing the potential technical limitations of the abdominal micro-vascular anastomosis, and potentially broadening the scope of research and facilitating skill acquisition.
Authors
Jack Zakrzewski (1), Li Lu (2), John Iguidbashian (2), Ludmila Khailova (2), Jesse Davidson (3), James Jaggers (3), Matthew Stone (3)
Institutions
(1) University of Colorado, Anschutz Medical Center, Aurora, CO, Denver, CO, (2) University of Colorado, Aurora, CO, (3) Children's Hospital Colorado, Aurora, CO
Methods: 10-12 week-old (20-30 grams) wild type mice underwent heart procurement. Hearts were then attached to a temperature- and pressure-controlled ex vivo perfusion system constructed from commercially available laboratory equipment. Hearts were perfused with acellular, unoxygenated Krebs-Henseleit (KH) buffer at 4⁰C for 90 minutes. Control hearts were maintained on ice under cold static preservation (CSP) conditions. After the preservation period, the donor grafts were transplanted onto the cervical vessels of a recipient mouse using a modified vascular cuff technique: the donor aorta was attached to the recipient carotid artery, and the donor pulmonary artery was attached to the recipient external jugular vein. Hearts were then allowed to re-perfuse for 120 minutes prior to echocardiographic assessment of function. As the left ventricle is unloaded in this model, fractional shortening and fractional area change were used to assess function.
Results: Overall graft survival at 120 minutes after cervical heart transplantation was similar between EVHP (n=18) and CSP (n=15) groups (72% vs. 67%, p=0.6 via Log-rank testing) (figure). Echocardiography demonstrated EVHP hearts had significantly improved graft function compared to CSP hearts: Short axis fractional shortening change 24.8% vs. 14.1%, p=0.005; short axis fractional area change 26.0% vs. 17.9%, p=0.03.
Conclusions: Our novel murine EVHP and heart transplantation model provides similar animal and graft post-transplantation survival compared to standard graft cold static preservation. Graft assessment with echocardiography demonstrated superior function of EVHP treated hearts compared to CSP controls. This model provides a new way to rapidly prototype various EVHP strategies, perfusate formulations, and techniques in a reproducible and cost-effective murine model. This approach can serve as a proof-of-concept testing platform before advancing to larger animal models. Cervical transplantation facilitates dynamic graft assessment via echocardiography in short-term survival models. Additionally, the success rate of the modified cervical cuff anastomosis technique allows for the consistent study of mechanisms of post-transplant graft failure, minimizing the potential technical limitations of the abdominal micro-vascular anastomosis, and potentially broadening the scope of research and facilitating skill acquisition.
Authors
Jack Zakrzewski (1), Li Lu (2), John Iguidbashian (2), Ludmila Khailova (2), Jesse Davidson (3), James Jaggers (3), Matthew Stone (3)
Institutions
(1) University of Colorado, Anschutz Medical Center, Aurora, CO, Denver, CO, (2) University of Colorado, Aurora, CO, (3) Children's Hospital Colorado, Aurora, CO