Date of Submission
Anna Kloc, Ph.D.
Myocarditis, Human Heart Tissue, Cytokine Expression Levels, Cardiac Disease Process, DNA and RNA, Virus
Myocarditis, Heart Diseases, Cytokines, DNA, RNA, Viruses
Myocarditis, Heart--Diseases, DNA, RNA, Viruses
The heart is a major organ whose function is to transport nutrients and waste throughout the body. This organ can become infected by pathogens, such as viruses, bacteria, or parasites. Infection of the middle heart layer, or myocardium, is often caused by a viral agent. This disease has three stages: viral infiltration, adaptive immune system activation, and finally either viral clearance or cardiac cell remodeling. During this process the immune system will begin to secrete cytokines, which are signaling molecules that alert other members of the immune pathways, and also participate in cardiac remodeling. Evaluating the correlation between the cytokine expression levels with the viruses present in cardiomyopathy-positive heart tissue samples can lead to a better understanding of cardiac disease process, and aid in the development of new diagnostic tools.
In order to accomplish this study nucleic acid (DNA and RNA) from heart tissues obtained from cardiomyopathy-positive samples, as well as donor samples, was isolated. The DNA was then used in a PCR reaction with viral primers corresponding to DNA viruses. Next, RNA was used to synthesize cDNA. With cDNA made two types of analyses took place: a PCR with primers specific to RNA viruses was performed to identify viral genomes, and a qPCR assay was done to evaluate the expression levels of cytokines.
The most common viruses identified in the study were HRSV, Herpesviruses 5/7, and Hepatitis-C virus. The virus that was least prevalent was Coxsackievirus-B3. The analysis of cytokine expression profiles and genes involved in cardiac remodeling revealed that samples BIF28 and 48CAF had the highest expression levels of immune system, and cardiac, markers. The two markers with increased expression levels were Tnnt2 and TGF-β. When the cytokine expression levels were compared for each of the three heart layers (endocardium, epicardium, and myocardium) it was seen the epicardium had the highest expression levels, suggesting highest levels of inflammation. In sum, the generated data revealed a correlation between viral infection and the degree of heart inflammation. Interestingly, based on samples analyzed in this study, I showed that distinct layers of the heart can have various inflammatory profiles, suggesting different levels of cardiac damage. Follow up studies will help delineate the association of viral infection of cardiac muscle and inflammation, which may help develop better diagnostic tools.
Galeotos, Gabriel, "Assessment of Virus-Induced Myocarditis in Human Heart Tissue Samples" (2021). Honors Theses. 44.