Browsing by Author "Liu, Chun"

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    Anti-Ferroptotic Treatment Deteriorates Myocardial Infarction by Inhibiting Angiogenesis and Altering Immune Response
    (MDPI, 2024-06-26) Stairley, Rebecca A.; Trouten, Allison M.; Li, Shuang; Roddy, Patrick L.; DeLeon-Pennell, Kristine Y.; Lee, Kyu-Ho; Sucov, Henry M.; Liu, Chun; Tao, Ge; Pediatrics, School of Medicine
    Mammalian cardiomyocytes have limited regenerative ability. Cardiac disease, such as congenital heart disease and myocardial infarction, causes an initial loss of cardiomyocytes through regulated cell death (RCD). Understanding the mechanisms that govern RCD in the injured myocardium is crucial for developing therapeutics to promote heart regeneration. We previously reported that ferroptosis, a non-apoptotic and iron-dependent form of RCD, is the main contributor to cardiomyocyte death in the injured heart. To investigate the mechanisms underlying the preference for ferroptosis in cardiomyocytes, we examined the effects of anti-ferroptotic reagents in infarcted mouse hearts. The results revealed that the anti-ferroptotic reagent did not improve neonatal heart regeneration, and further compromised the cardiac function of juvenile hearts. On the other hand, ferroptotic cardiomyocytes played a supportive role during wound healing by releasing pro-angiogenic factors. The inhibition of ferroptosis in the regenerating mouse heart altered the immune and angiogenic responses. Our study provides insights into the preference for ferroptosis over other types of RCD in stressed cardiomyocytes, and guidance for designing anti-cell-death therapies for treating heart disease.
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    Method for Detection and Quantification of Non-Invasive Skin Sympathetic Nerve Activity
    (IEEE, 2018) Liu, Chun; Wong, Johnson; Doytchinova, Anisiia; Chen, Peng-Sheng; Lin, Shien-Fong; Medicine, School of Medicine
    Sympathetic nerve activity is an important trigger of cardiac arrhythmia. Our laboratory recently developed a new method for non-invasive recording of the skin sympathetic nerve activity (SKNA) using conventional electrocardiography (ECG) patch electrodes. Recent studies showed that SKNA can adequately estimate sympathetic tone in humans. In order to improve the analysis of SKNA, we developed automatic standard assessment system based on the concept of microneurography and applied to non-invasive SKNA recording via 4 steps of signal processing. Every parameters in procedures can be manually selected by users in order to meet requirements. After using these signal processing, the results obtained by this system show improved nerve burst morphology and trend. Intuitive nerve discharge pattern and occurrence frequency can be automatically generated. Verification of the method with the cold water pressor test data further established the reliability and usefulness of the system. This new method offered a convenient tool to evaluate SKNA for comprehensive and detailed application in neurocardiology. The analysis system may facilitate the study between SKNA and cardiac arrhythmia, thus advance the field of neurocardiology research.