title: Heterotopic abdominal heart transplantation in rats for functional studies of ventricular unloading.
abstract: BACKGROUND
  Chronic changes in mechanical load regulate long-term cardiac function. Chronic overload of the ventricle results in myocardial failure. Clinical use of ventricular assist devices shows that chronic reduction in load has a number of different consequences on the myocardium, including beneficial reverse remodeling as well as undesired remodeling (e.g., myocardial atrophy and fibrosis, both of which could have negative functional implications). The complex response to mechanical unloading necessitates reproducible animal models of mechanical unloading for use in the laboratory. This article aims to describe the operative technique of two animal models of mechanical unloading in detail, to enable the reproducible use of these animal models.
  
  
  METHODS
  In 1964, Abbott et al first described the heterotopic abdominal heart transplantation technique as a means to study the biology of transplanted cardiac grafts. This involves an aorto-aortic anastomosis and a pulmonary artery to inferior vena cava anastomosis. In this model, the left ventricle is virtually completely volume unloaded, receiving only thebesian venous return, and substantially but not entirely pressure unloaded. In this report we describe two refined techniques for mechanical unloading of healthy or failing hearts based on experience with over 500 operations.
  
  
  RESULTS
  We describe an operative technique, including cardioprotective strategies, that provides a model of mechanical unloading with no immunological rejection and allows measurements of parameters of myocardial structure and function for many months. We describe a refined technique that achieves a lesser degree of left ventricular volume unloading, involving transplantation of both heart and lungs via a single aorto-aortic anastomosis.
  
  
  CONCLUSIONS
  This article is the first to describe these two techniques in sufficient detail to enable novices to attempt and understand these operations and the differences between them. The technique we describe provides an effective and reproducible model of complete and partial mechanical unloading.
authors.affiliation: Laboratory of Cell Electrophysiology, Harefield Heart Science Centre, Imperial College London, London UB9 6JH, United Kingdom. michael.ibrahim08@imperial.ac.uk
authors.forename: Michael
authors.initials: M
authors.lastname: Ibrahim
authors.forename: Manoraj
authors.initials: M
authors.lastname: Navaratnarajah
authors.forename: Punam
authors.initials: P
authors.lastname: Kukadia
authors.forename: Christopher
authors.initials: C
authors.lastname: Rao
authors.forename: Urszula
authors.initials: U
authors.lastname: Siedlecka
authors.forename: James E
authors.initials: JE
authors.lastname: Cartledge
authors.forename: Gopal K
authors.initials: GK
authors.lastname: Soppa
authors.forename: Carin
authors.initials: C
authors.lastname: Van Doorn
authors.forename: Magdi H
authors.initials: MH
authors.lastname: Yacoub
authors.forename: Cesare M
authors.initials: CM
authors.lastname: Terracciano
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004452:Echocardiography; D006333:Heart Failure / Q000503:physiopathology*; D016027:Heart Transplantation / Q000379:methods*; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000503:physiopathology; D006353:Heart-Assist Devices; D008297:Male; D051381:Rats; D011917:Rats, Inbred Lew; D016042:Transplantation, Heterotopic / Q000379:methods*; D018754:Ventricular Dysfunction / Q000503:physiopathology*; D020257:Ventricular Remodeling