Duchenne muscular dystrophy (DMD) is an X-linked genetic disease causing progressive muscle weakness. There is no cure for DMD, with affected boys typically dying due to respiratory or cardiac failure. Golden retriever muscular dystrophy (GRMD) is a genetically homologous model that has been used increasingly to study pathogenesis and potential treatments for DMD. GRMD dogs develop cardiomyopathy similar to DMD, but the disease progression has not been well defined. In this study, we evaluated echocardiography and cardiac MRI in 24 adult GRMD dogs at different ages. Left heart systolic function, wall thickness, and myocardial strain were assessed with echocardiography. Features evaluated with cardiac MRI included LV function, chamber size, myocardial mass, and late gadolinium enhancement (LGE). Separately, ten GRMD dogs were evaluated with circumferential strain twice in a 12-month period. Taken together, our results showed gradual decline of systolic function in GRMD dogs. The decrease of ejection fraction (EF) in echocardiography correlated well with age and identified 31 months as the approximate age at which EF falls below 55%. Circumferential strain appeared to be more sensitive than EF in early disease detection and declined with disease progression. Evidence of LV chamber dilatation provided proof of dilated cardiomyopathy. The LGE imaging showed LV lateral wall lesions and earlier involvement of the anterior septum in GRMD dogs. In conclusion, this study showed the natural history of GRMD cardiomyopathy largely parallels that of DMD. In addition, circumferential strain and EF were good biomarkers of disease progression.
PhD Candidate / Graduate Assistant Research
Texas A&M University
Lee-Jae "Jack" Guo is a PhD Candidate in Texas A&M University, studying cardiomyopathy of golden retriever muscular dystrophy (GRMD) model with Dr. Joe Kornegay. Dr. Guo is a veterinarian from Taiwan, and working on cardiovascular translational research in Texas A&M University. Dr. Guo’s research focuses include animal model of human cardiovascular diseases, mechanical circulatory support, and cardiovascular imaging. Dr. Guo is currently working on the natural history and imaging biomarkers for GRMD cardiomyopathy, to better establish the GRMD model for therapeutic testing.
Friday, June 15
1:45 PM – 2:00 PM
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