title: Green tea extract protects endothelial progenitor cells from oxidative insult through reduction of intracellular reactive oxygen species activity.
abstract: OBJECTIVE
  Many studies have reported that tea consumption decreases cardiovascular risk, but the mechanisms remain unclear. Green tea is known to have potent antioxidant and free radical scavenging activities. This study aimed to investigate whether green tea extract (GTE) can protect endothelial progenitors cells (EPCs) against oxidative stress through antioxidant mechanisms.
  
  
  METHODS
  Mononuclear cells (MNCs) were isolated from peripheral blood by density gradient centrifugation with Ficoll. The cells were then plated on fibronectin-coated culture dishes. After 7 days of culture, EPCs were characterized as adherent cells double positive for DiI-ac-LDL uptake and lectin binding. EPCs were further identified by assessing the expression of CD34/45, CD133, and KDR. EPCs were then treated with hydrogen peroxide (H2O2) at doses of 50, 100, 200 µM and incubated with or without GTE (25 µg/ml). The intracellular reactive oxygen species (ROS) levels were detected by flow cytometry using a 2',7'-dichlorofluorescein diacetate (DCF-DA) fluorescent probe.
  
  
  RESULTS
  GTE ameliorated the cell viability of EPCs induced by H2O2 at doses of 50, 100, 200 µM for about 25.47, 22.52, and 11.96% higher than controls, respectively. GTE also decreased the intracellular ROS levels of EPCs induced by H2O2 at doses of 50, 100, 200 µM for about 84.24, 92.27, and 93.72% compared to controls, respectively.
  
  
  CONCLUSIONS
  GTE improves cell viability by reducing the intracellular ROS accumulation in H2O2-induced EPCs.
authors.affiliation: Medical Research Center, Faculty of Medicine, Maranatha Christian University, Jl. Prof. Drg. Suria Sumantri 65, Bandung 40164, West Java, Indonesia.
authors.forename: Wahyu
authors.initials: W
authors.lastname: Widowati
authors.affiliation: Biomolecular and Biomedical Research Center, Aretha Medika Utama, Jl. Babakan Jeruk 2 no 9, Bandung, 40163, West Java, Indonesia.
authors.forename: Rahma Micho
authors.initials: RM
authors.lastname: Widyanto
authors.affiliation: Medical Research Center, Faculty of Medicine, Maranatha Christian University, Jl. Prof. Drg. Suria Sumantri 65, Bandung 40164, West Java, Indonesia.
authors.forename: Winsa
authors.initials: W
authors.lastname: Husin
authors.affiliation: Medical Research Center, Faculty of Medicine, Maranatha Christian University, Jl. Prof. Drg. Suria Sumantri 65, Bandung 40164, West Java, Indonesia.
authors.forename: Hana
authors.initials: H
authors.lastname: Ratnawati
authors.affiliation: Faculty of Pharmacy, Pancasila University, Jl Jagakarsa, Jakarta, Indonesia.
authors.forename: Dian Ratih
authors.initials: DR
authors.lastname: Laksmitawati
authors.affiliation: Department of Medical Chemistry and Biochemistry, Faculty of Medicine, Lambung Mangkurat University, Banjarmasin, South Kalimantan, Indonesia.
authors.forename: Bambang
authors.initials: B
authors.lastname: Setiawan
authors.affiliation: Department of Pharmacology, Faculty of Medicine, Brawijaya University, Jl. Veteran, Malang, 65145, East Java, Indonesia.
authors.forename: Dian
authors.initials: D
authors.lastname: Nugrahenny
authors.affiliation: Stem Cell and Cancer Institute, JL. A. Yani no.2 Pulo Mas, Jakarta, 13210, Indonesia.
authors.forename: Indra
authors.initials: I
authors.lastname: Bachtiar
keywords: Antioxidant; Endothelial progenitor cells; Green tea; Oxidative stress; Reactive oxygen species