Transesophageal echocardiography in healthy young adult male baboons (Papio hamadryas anubis): Normal cardiac anatomy and function in subhuman primates compared to humans

Abstract

Implantable, viable tissue engineered cardiovascular constructs are rapidly approaching clinical translation. Species typically utilized as preclinical large animal models are food stock ungulates for which cross species biological and genomic differences with humans are great. Multiple authorities have recommended developing subhuman primate models for testing regenerative surgical strategies to mitigate xenotransplant inflammation. However, there is a lack of specific quantitative cardiac imaging comparisons between humans and the genomically similar baboons (Papio hamadryas anubis). This study was undertaken to translate to baboons transesophageal echocardiographic functional and dimensional criteria defined as necessary for defining cardiac anatomy and function in the perioperative setting. Seventeen young, healthy baboons (approximately 30 kg, similar to 5 year old children) were studied to determine whether the requisite 11 views and 52 measurement parameters could be reliably acquired by transesophageal echocardiography (TEE). The obtained measurements were compared to human adult normative literature values and to a large relational database of pediatric “normal heart” echo measurements. Comparisons to humans, when normalized to BSA, revealed a trend in baboons toward larger mitral and aortic valve effective orifice areas and much larger left ventricular muscle mass and wall thickness, but similar pulmonary and tricuspid valves. By modifying probe positioning relative to human techniques, all recommended TEE views except transgastric could be replicated. To supplement, two transthoracic apical views were discovered that in baboons could reliably replace the transgastric TEE view. Thus, all requisite echo views could be obtained for a complete cardiac evaluation in Papio hamadryas anubis to noninvasively quantify cardiac structural anatomy, physiology, and dimensions. Despite similarities between the species, there are subtle and important physiologic and anatomic differences when compared to human.

The trait specific timing of accelerated genomic change in the human lineage

“…3 ), hinting at continued evolution of these traits across timepoints. These observations mirror common observed morphological differences between humans and other great apes as our skeleton structures, brain size and organization, and heart morphology have all undergone significant changes 49–52 .…”

Cardiac xenotransplantation: from concept to clinic

“…are typically used as recipients for XTx experiments. 104 Bert et al 141 found high structural and quantitative similarities between the healthy baboon and human hearts in echocardiography studies; specific exceptions are an elevated left ventricular mass in baboons, low pulmonary vascular resistance, thickened walls of pulmonary artery and aorta, an oversized mitral valve orifice and a very large left coronary artery. As baboons are much smaller than humans (20 vs. 75 kg), juvenile swine must be used as organ donors for XTx experiments.…”

Performance of allogeneic bioengineered replacement pulmonary valves in rapidly growing young lambs

“…Measurements were obtained both at sedated baseline and at a maximum cardiac output achieved via dobutamine administration. 19,20 Two-dimensional images for dimensions (Figure E1) and Doppler-derived hemodynamic measurements were captured digitally (X7-2T probe; Philips, Amsterdam, The Netherlands). Pressure gradients were calculated by a modified Bernoulli equation.…”