According to the World Health Organization (WHO), around 17.9 million people die each year due to heart disease making it the top cause for death. This makes investigating the factors and causes of heart disease a prime focus of research given that many non-injury deaths in adults in industrialized countries are due to cardiac issues.
The treatment of cardiac arrest can be considered successful given that the treatment regime involves chest compressions, defibrillation, and administering epinephrine. The lack of more options to address this serious condition requires further studies. This becomes even more important given that the disease claims so many lives and has huge impacts on economic and social levels.
One way to look at filling the gaps is to use animal models and cells. While the use of rodents has revealed molecular patterns and functions, differences in the ionic current generation between rodents and humans make the application of data generated questionable. This brings in the use of swine or pig heart models.
Though there are differences between human and swine hearts, both use nonesterified fatty acids as the major source of energy. The occurrence of congenital heart anomalies in pigs has allowed them to be used to study septal defects and other such diseases. Similarities in anatomy especially the arrangement of blood vessels in the heart regions allow for pig hearts to serve as a more reliable system to study myocardial ischemia.
Apart from these points, 2014-published research in the Journal of the American Association for Laboratory Animal Science also reported the use of swine to study atherosclerosis given the similarity in the levels of low-density lipoproteins and high-density lipoproteins. Thus, the hemodynamic values and the circulation make the use of swine hearts suitable in cardiovascular research given the morbidity of the disease.
The maintenance of many vascular functions is done by Endothelial Cells; several studies using human umbilical vein endothelial cells (HUVECs) have allowed understanding their role in health and disease. Culturing mouse heart endothelial cells involves the use of antibodies for isolating the cells given the presence of other cells such as fibroblasts. The isolation of pig heart endothelial cells becomes challenging as enzymes cannot be used given the large size of swine hearts.
A team led by Hätinen reported the fast isolation of endothelial cells for research in the BMC Molecular and Cell Biology in 2019. The protocol can allow the isolation of endothelial cells in 1-2 hours using PBS and collagenase perfusion followed by pooling and plating to yield 2 × 105 to 3 × 105 endothelial cells from each heart. Immunostaining and fluorescence assisted cell sorting (FACS) for CD 31 confirmed that the cells were endothelial cells. These cells have the potential to be used for cell biology as well as genomics and transcriptomics to add value to cardiac biology.
Given the death and burden of cardiac disease in today’s world, the use of swine heart cells offers a suitable in vitro model to study the mechanisms of various heart diseases.
Lelovas, P. P., Kostomitsopoulos, N. G., & Xanthos, T. T. (2014). A comparative anatomic and physiologic overview of the porcine heart. Journal of the American Association for Laboratory Animal Science: JAALAS, 53(5), 432–438.
Hätinen, O.A., Lähteenvuo, J.E., Korpela, H.J. et al. (2019). Isolation of fresh endothelial cells from porcine heart for cardiovascular studies: a new fast protocol suitable for genomic, transcriptomic and cell biology studies. BMC Molecular and Cell Biology 20; 32.