Publications by authors named "Magdy Girgis"

Circadian rhythms play a crucial role in the regulation of various physiological processes, including cardiovascular function and metabolism. Exercise provokes numerous beneficial adaptations in heart, including physiological hypertrophy, and serves to shift circadian rhythms. This study investigated the impact of time-restricted exercise training on exercise-induced adaptations in the heart and locomotor activity rhythms.

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Many anticancer therapies cause serious cardiovascular complications that degrade quality of life and cause early mortality in treated patients. Specifically, doxorubicin is known as an effective anticancer agent that causes cardiomyopathy in treated patients. There has been growing interest in defining the role of endothelial cells in cardiac damage by doxorubicin.

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Although vitamin D3 (VitD3) prevents angiogenesis in cancer, VitD3 deficiency is associated with greater incidence of cardiovascular events in patients. We examined the influence of VitD3 on the angiogenic potential of mesenchymal stem cells (MSCs). VitD3 treatment increased the expression of proangiogenic molecules in MSCs, which exhibited an endothelial cell-like phenotype and promoted vascularization and .

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Human umbilical cord blood (hUCB) contains diverse populations of stem/progenitor cells. Whether hUCB-derived nonhematopoietic cells would induce cardiac repair remains unknown. To examine whether intramyocardial transplantation of hUCB-derived CD45Lin nonhematopoietic cellular fraction after a reperfused myocardial infarction in nonimmunosuppressed rats would improve cardiac function and ameliorate ventricular remodeling.

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Rationale: Extracellular vesicles (EVs) are tiny membrane-enclosed droplets released by cells through membrane budding or exocytosis. The myocardial reparative abilities of EVs derived from induced pluripotent stem cells (iPSCs) have not been directly compared with the source iPSCs.

Objective: To examine whether iPSC-derived EVs can influence the biological functions of cardiac cells in vitro and to compare the safety and efficacy of iPSC-derived EVs (iPSC-EVs) and iPSCs for cardiac repair in vivo.

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Signal transducers and activators of transcription 3 (STAT3) is known to participate in various cardiovascular signal transduction pathways, including those responsible for cardiac hypertrophy and cytoprotection. However, the role of STAT3 signaling in cardiomyocyte autophagy remains unclear. We tested the hypothesis that Angiotensin II (Ang II)-induced cardiomyocyte hypertrophy is effected, at least in part, through STAT3-mediated inhibition of cellular autophagy.

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Rationale: The role of interleukin (IL)-6 in the pathogenesis of cardiac myocyte hypertrophy remains controversial.

Objective: To conclusively determine whether IL-6 signaling is essential for the development of pressure overload-induced left ventricular (LV) hypertrophy and to elucidate the underlying molecular pathways.

Methods And Results: Wild-type and IL-6 knockout (IL-6(-/-)) mice underwent sham surgery or transverse aortic constriction (TAC) to induce pressure overload.

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Fibroblast growth factor 23 (FGF23) is a hormone released primarily by osteocytes that regulates phosphate and vitamin D metabolism. Recent observational studies in humans suggest that circulating FGF23 is independently associated with cardiac hypertrophy and increased mortality, but it is unknown whether FGF23 can directly alter cardiac function. We found that FGF23 significantly increased cardiomyocyte cell size in vitro, the expression of gene markers of cardiac hypertrophy, and total protein content of cardiac muscle.

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