Establishing a Swine Model of Post-myocardial Infarction Heart Failure for Stem Cell Treatment

Summary

We sought to establish a swine model of heart failure induced by left circumflex artery blockage and rapid pacing to test the effect and safety of intramyocardial administration of stem cells for cell-based therapies.

Abstract

Although advances have been achieved in the treatment of heart failure (HF) following myocardial infarction (MI), HF following MI remains one of the major causes of mortality and morbidity around the world. Cell-based therapies for cardiac repair and improvement of left ventricular function after MI have attracted considerable attention. Accordingly, the safety and efficacy of these cell transplantations should be tested in a preclinical large animal model of HF prior to clinical use. Pigs are widely used for cardiovascular disease research due to their similarity to humans in terms of heart size and coronary anatomy. Therefore, we sought to present an effective protocol for the establishment of a porcine chronic HF model using closed-chest coronary balloon occlusion of the left circumflex artery (LCX), followed by rapid ventricular pacing induced with pacemaker implantation. Eight weeks later, the stem cells were administered by intramyocardial injection in the peri-infarct area. Then the infarct size, cell survival, and left ventricular function (including echocardiography, hemodynamic parameters, and electrophysiology) were evaluated. This study helps establish a stable preclinical large animal HF model for stem cell treatment.

Introduction

Cardiovascular diseases, coronary artery disease (CAD) in particular, remain the major cause of morbidity and mortality in Hong Kong and worldwide¹. In Hong Kong, a 26% increase from 2012 to 2017 of the number of CAD patients treated under the Hospital Authority was projected². Among all CADs, acute myocardial infarction (MI) is a leading cause of death and subsequent complications, such as heart failure (HF). These contribute to significant medical, social, and financial burdens. In patients with MI, thrombolytic therapy or primary percutaneous coronary intervention (PCI) is an effective therapy in preserving life, but ....

Protocol

All animal experiments were performed in accordance with the Guide for the Care and Use of Laboratory Animals published by the US National Institutes of Health and regulations of the University of Hong Kong, and the protocol was approved by the Committee on the Use of Live Animals in Teaching and Research (CULTAR) at the University of Hong Kong.

NOTE: Female farm pigs weighing 35-40 kg (9-12 months old) were used for this study. The flowchart of this experiment is shown in Figure 1.

1. Surgical procedures

1. Anesthesia and preparation of the animal
   1. Fast the anima....

Results

Mortality
A total of 24 pigs were used in this study. Three of them died during MI induction because of sustained VT. One animal died in the open-heart surgery for cell injection because of wound bleeding. Two animals died because of severe infection. Two animals were excluded because of slight EF reduction (LVEF reduction > 40% of baseline). As a result, 16 animals completed the whole study protocol.

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Discussion

Standard animal models are of paramount importance to understand the pathophysiology and mechanisms of diseases and test novel therapeutics. Our protocol establishes a porcine model of HF induced by left circumflex artery blockage and rapid pacing. Eight weeks after the induction of MI, the animals developed significant impairment of LVEF, LVEDD, LVESD, +dP/dt, and ESPVR. This protocol also tests the administration method of stem cell therapy for heart regeneration by intramyocardial injection. The infarct size, and card.......

Materials

Name	Company	Catalog Number	Comments
Amiodarone	Mylan	-	-
Anaesthetic machines and respirator	Drager	Fabius plus XL	-
Angiocath	Becton Dickinson	381147	-
Anti-human nuclear antigen	abcam	ab19118	-
Axio Plus image capturing system	Zeiss	Axioskop 2 PLUS	Axioskop 2 plus
AxioVision Rel. 4.5 software	Zeiss	-	-
Baytril	Bayer	-	enrofloxacin
Betadine	Mundipharma	-	-
CardioLab Electrophysiology Recording Systems	GE Healthcare	G220f	-
Culture media	MesenCult	05420	-
Cyclosporine	Novartis	-	-
Defibrillator	GE Healthcare	CardioServ	-
Dorminal	TEVA	-	-
Echocardiographic system	GE Vingmed	Vivid i	-
EchoPac software	GE Vingmed	-	-
Electrophysiological catheter	Cordis Corp	-	-
Embozene Microsphere	Boston Scientific	17020-S1	700 μm
Endotracheal tube	Vet Care	VCPET70PCW	Size 7
Ethanol	VWR chemicals	20821.33	-
Formalin	Sigma	HT501320	10%
IVC balloon Dilatation Catheter	Boston Scientific	3917112041	Mustang
JR4 guiding catheter	Cordis Corp	67208200	6F
Lidocaine	Quala	-	-
Mersilk	Ethicon	W584	2-0
Metoprolol succinate	Wockhardt	-	-
Microtome	Leica	RM2125RT	-
Mobile C arm fluoroscopy equipment	GE Healthcare	OEC 9900 Elite	-
Pacemaker	St Jude Medical	PM1272	Assurity MRI pacemaker
Pacemaker generator	St Jude Medical	Merlln model 3330	-
Pressure-volume catheter	CD Leycom	CA-71103-PL	7F
Pressure–volume signal processor	CD Leycom	SIGMA-M	-
Programmable Stimulator	Medtronic Inc	5328	-
PTCA Dilatation balloon Catheter	Boston Scientific	H7493919120250	MAVERICK over the wire
Ramipril	TEVA	-	-
Sheath introducer	Cordis Corp	504608X	8F, 9F, 12F
Steroid	Versus Arthritis	-	-
Temgesic	Nindivior	-	buprenorphine
Venous indwelling needle	TERUMO	SR+OX2225C	22G
Vicryl	Ethicon	VCP320H	2-0
Xylazine	Alfasan International B.V.	-	-
Zoletil	Virbac New Zealand Limited	-	tiletamine+zolezepam