Affiliations: [a] “S Maugeri Foundation” IRCCS, Medical Center of Lumezzane, Via Mazzini, Lumezzane (BS), Italy. e-mail: evpasini@libero.it
| [b] Medical Molecular Biology Unit, Institute of Child Health, University College London, London, UK | [c] VA Ann Arbor Health Care System, Division of Cardiology, University of Michigan, Ann Arbor, MI, USA | [d] Division of Human Anatomy, Department of Biomedical Sciences and Biotechnology, University of Brescia, Brescia, Italy | [e] Metabolic Service and Nutritional Pathophysiology, S. Maugeri Foundation, IRCCS, Scientific Institute of Montescano, Pavia, Italy | [f] Center for Heart and Vessel Preclinical Studies, St. John Hospital and Medical Center, Wayne State University School of Medicine, Detroit, MI, USA
Abstract: Clinical data suggest that people who use green tea have a lower cardiovascular risk. However, the exact mechanisms of these cardioprotective effects are unknown. We know that STAT1 plays a critical role in promoting apoptotic cell death and STAT3 may antagonise STAT1 and protect cardiac myocytes from ischaemia/reperfusion (I/R) injury. More recently it has been shown that specific molecules such as epigallocatechin-3-gallate (EGCG), which is present in green tea extract (GTE), have antioxidant properties. Considering that: (i) oxygen free radicals (OFR) are produced during myocardial I/R insult and (ii) OFR are responsible for reperfusion cardiac damage, we therefore investigated whether chronic administration per os of GTE reduced I/R damage in the Langendorff perfused isolated rat heart. In addition we evaluated myocardial content of STAT1 and STAT3 and degree of apoptosis. In Sprague–Dawley isolated hearts, GTE reduced the ischaemic mechanical insult, prolonged STAT3 activation/phosphorylation and reduced STAT1 activation with consequent less cell apoptosis. These results show that chronic treatment with GTE protects the heart from I/R injury. Activation of prosurvival STAT3 over the pro-apoptotic STAT1 could be one of the molecular mechanisms involved in green tea-mediated cardiopretection.
Keywords: Green tea, Heart, Ischaemia, Reperfusion, Apoptosis
