Swine show high resemblance to humans in regard to their hemodynamic
parameters. However, direct interspecies and intraspecies comparisons should be made
prudently. The same pattern of increased innervation is also present in the Purkinje fiber
network. The Purkinje system of swine is characterized by fast electrical coupling.
Purkinje fibers are connected to the ventricular myocardium at Purkinje– ventricular
junctions. In humans, dogs, and rabbits, these junctions have been identified only
subendocardially, whereas they usually lie transmurally in sheep and pigs. At the
microscopic level, the swine conduction system appears to possess more connective than
elastic tissue, compared with that in humans (Maher, 2013).
The porcine heart responds similarly to the human heart after infraction and
presents arrhythmogenity with reperfusion, contrary to the canine heart with its multiple
preexisting collateral anastomoses. For human cases where the infraction has developed
gradually, allowing time for the formation of collateral circulation, dogs might serve as an
appropriate animal model. Swine could mimic such a situation after gradual occlusion of
a coronary artery by using balloon angioplasty and the administration of an atherogenic
diet. When compared with sheep, swine resemble humans more closely regarding the
healing characteristics of the myocardium, given that in ruminants, healing is
characterized by the formation of collagenous scars. Therefore, pig heart assembles much
similarities compared to another species with human heart and it has potential to be used
as basic research especially for tissue replacement for organ transplantation (Ng, 2011).
Decellularization and Recellularization to Construct a Whole-Heart
The most robust and effective decellularization protocols include a combination
of physical, chemical, and enzymatic approaches. Decellularized tissues and organs have
been successfully used in a variety of tissue engineering/regenerative medicine
applications, and the decellularization methods used vary as widely as the tissues and
organs of interest. The efficiency of cell removal from a tissue is dependent on the origin
of the tissue and the specific physical, chemical, and enzymatic methods that are used.
Each of these treatments affect the biochemical composition, tissue ultrastructure, and
mechanical behavior of the remaining extracellular matrix (ECM) scaffold, which in turn,
affect the host response to the material. Herein, the most commonly used
decellularization methods are described, and consideration give to the effects of these
methods upon the biologic scaffold material (Ott et al., 2008).
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