Cardiovascular System Disorders: Heart Disease
This 63-year-old man’s history revealed that his father that died from a myocardial infarction (MI) which is the result of immediate occlusion of the blood flow to the coronary vessels. The most common causes of death from an MI are decreased cardiac output, fibrillation of the heart, rupture of the heart and pooling of the blood from pulmonary edema which resulted from the increased pressure within the heart. Symptoms presented by the patient are an indication to the healthcare staff and hopefully to the patient that lifestyle changes are needed. This patient is fortunate that he has sought medical attention and has been taken to the cath lab to reveal that he has a coronary artery blockage. If this patient did not seek medical attention, myocardial cell death would continue to occur with the possibility of sudden cardiac death. Cardiovascular disease (CVD) still accounts for more than one-third of all human mortality and remains the leading cause of death worldwide (Chiong, et al., 2011). Some deaths occur suddenly such as with myocardial infarction (MI) and other deaths will occur over a period of time as a result of heart failure.
Cell death can either be acute or progressive as with cardiac disease such as HF, MI and ischemic/reperfusion. Cell death is an important component in the pathogenesis of cardiac disease, new cells requires programmed elimination of older, damaged or less functional tissue, an unexpected loss of cells accelerates growth of similar cells, in a healing process that is essential for functional homeostasis (Tian, Cui, Yang, Zhou, & Hu, 2015). There are three mechanisms of cell death, necrosis, apoptosis and autophagy occurring in the cardiac cells.
How it works
Apoptosis is a regulated process by the body that is associated with cardiac myocyte loss. Even though apoptosis is a normal process due to the proliferation of new cells, the myocyte loss places increased stress on the remaining myocytes (Hammer & McPhee, 2019). This can lead to hypertrophy and continued apoptosis. Apoptosis is mediated by two pathways, intrinsic and extrinsic. The extrinsic pathway can be triggered by the death ligand or death receptors (DRs) which starts the death-inducing signaling complex (DISC), tumor necrosis factor which is expressed by cardiac myocytes and have been associated with cardiac pathology (Chiong, et al., 2011). The extrinsic pathway can also activate the intrinsic apoptotic pathway which is involved with the mitochondria and endoplasmic reticulum (ER) of the cardiac myocytes. The mitochondria and are strategically distributed to allow for efficient ATP supply to the high-energy demand of the heart.
However, because the mitochondria also contribute to cell death in response to multiple stressors (Chiong, et al., 2011). The release of Bcl-2 family proteins are the main regulators of the intrinsic pathway with the primary event of the permeabilization of the outer mitochondrial membrane (OMM) resulting in the release of apoptogens (Konstantinidis, Whelan, & Kitsis, 2012). Apart from biochemical processes occurring in the dying cell, execution ultimately involves the orderly removal of cell debris. Thus, cell death is an essential part of tissue renewal (Tian, Cui, Yang, Zhou, & Hu, 2015). In this case study, the essential treatment is to decrease the stressors on this man’s body to maintain homeostasis within his cardiac system to prevent further damage on the cellular and muscular level of his heart.
- Chiong, M., Wang, V., Pedrozo, D., Cao, J., Troncoso, R., & Ibacache, M. (2011, December 22). Cardiomyocyte death: mechanisms and translational implications. Retrieved from www,ncbi.nlm.gov: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3252742/
- Hall, J. E. (2016). Guyton and Hall Textbook of Medical Physiology, Thirteenth Edition. Philadelphia: Elsevier.
- Hammer, G. D., & McPhee, S. J. (2019). Pathophysiology of Disease: An Introduction to Clinical Medicine. New York: McGraw-Hill Education.
- Konstantinidis, K., Whelan, R., & Kitsis, R. (2012, May 17). Mechanisms of Cell Death in Heart Disease. Retrieved from www.ahajournal.org: https://www.ahajournals.org/doi/full/10.1161/ATVBAHA.111.224915
- Tian, X., Cui, M., Yang, S., Zhou, Y., & Hu, D. (2015, May 1). Cell death, dysglycemia and myocardial infarction. Retrieved from www.ncbi.nlm.gov: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3917009/