title: Palmitate-induced apoptosis of microvascular endothelial cells and pericytes.
abstract: BACKGROUND
  Recent observations in the EURODIAB Complications Study demonstrated that markers of insulin resistance are strong risk factors for retinopathy incidence in patients with diabetes. However, the molecular mechanism underlying this remains to be elucidated. In this study, we investigated the influence of palmitate, a major saturated free fatty acid in plasma, on the apoptotic cell death of cultured microvascular endothelial cells (EC) and retinal pericytes.
  
  
  METHODS
  The intracellular formation of reactive oxygen species (ROS) was detected using the fluorescent probe CM-H(2)DCFDA. DNA synthesis was determined by measuring [(3) H]-thymidine incorporation into cells. DNA fragmentations of EC were quantitatively analyzed in an enzyme-linked immunosorbent assay, and DNA laddering was evaluated on agarose gel electrophoresis.
  
  
  RESULTS
  Palmitate increased ROS generation in microvascular EC. Furthermore, palmitate significantly inhibited DNA synthesis and induced apoptotic cell death in EC, which were completely prevented by an antioxidant, N-acetylcysteine. Palmitate up-regulated pericyte mRNA levels of a receptor for advanced glycation end products (AGE), and thereby potentiated the apoptotic effects of AGE on pericytes.
  
  
  CONCLUSIONS
  The results suggest that palmitate could induce apoptotic cell death in microvascular EC and pericytes through the overgeneration of intracellular ROS, and thus be involved in the development of diabetic retinopathy.
authors.affiliation: Division of Endocrinology and Metabolism, Department of Medicine, Kurume University School of Medicine, Kurume, Japan. shoichi@med.kurume-u.ac.jp
authors.forename: Sho-Ichi
authors.initials: S
authors.lastname: Yamagishi
authors.forename: Tamami
authors.initials: T
authors.lastname: Okamoto
authors.forename: Shinjiro
authors.initials: S
authors.lastname: Amano
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Inagaki
authors.forename: Kohachiro
authors.initials: K
authors.lastname: Koga
authors.forename: Mari
authors.initials: M
authors.lastname: Koga
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Choei
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Sasaki
authors.forename: Seiji
authors.initials: S
authors.lastname: Kikuchi
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Takeuchi
authors.forename: Zenji
authors.initials: Z
authors.lastname: Makita
mesh_terms: D017209:Apoptosis; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D005456:Fluorescent Dyes / Q000378:metabolism; D005786:Gene Expression Regulation; D017127:Glycation End Products, Advanced / Q000378:metabolism; D006801:Humans; D010168:Palmitates / Q000494:pharmacology*; D020286:Pericytes / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic / Q000235:genetics / Q000378:metabolism; D012160:Retina / Q000166:cytology; D013936:Thymidine / Q000378:metabolism
chemical_list: D005456:Fluorescent Dyes; D017127:Glycation End Products, Advanced; D010168:Palmitates; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic; D013936:Thymidine