title: Liposome-delivered ATP effectively protects the retina against ischemia-reperfusion injury.
abstract: OBJECTIVE
  We investigated the effect of ATP (ATP) encapsulated in liposomes (ATP-liposomes) on the level of inflammation and neuronal death in the retina induced by ischemia reperfusion (IR).
  
  
  METHODS
  Primary retinal ganglion cells treated with ATP-liposomes, empty liposomes, and phosphate buffer solution (PBS) were deprived of oxygen and glucose (OGD) for 6 h in vitro, in an anaerobic chamber. Plates were assessed for the proportion of necrotic versus apoptotic cells and for cell survival 12 h after OGD. For in vivo experiments, we induced retinal ischemia by unilateral elevation of intraocular pressure for 1 h by direct corneal canulation. Mice were injected with liposomes or PBS 24 h before IR, at the time of surgery, and every 24 h until sacrifice. Transmission electron microscopic analysis was used to identify necrotic and apoptotic cells in ischemic retinas. The changes in expression of pro-inflammatory genes 24 h post reperfusion were assessed by quantitative reverse transcription polymerase chain reaction (RT-PCR). Corresponding changes in protein abundances were analyzed by immunohistochemistry. Cell death was evaluated by direct counting of neurons in the ganglion cell layer (GCL) of flatmounted retinas 7 days post reperfusion.
  
  
  RESULTS
  Treatment with ATP-liposomes increases retinal ganglion cell (RGC) survival and decreases necrotic cell death following OGD. Injection of ATP-liposomes markedly decreased necrotic cell death in the GCL following retinal ischemia. The ATP-liposome treatment reduced the expression of pro-inflammatory genes, including that of interleukin 1β (Il1β), interleukin 6 (Il6), tumor necrosis factor (Thf), chemokine (C-C motif) ligand 2 (Ccl2), chemokine (C-C motif) ligand 5 (Ccl5), chemokine (C-X-C motif) ligand 10 (Cxcl10), intercellular adhesion molecule 1 (Icam1), and nitric oxide synthase 2 (Nos2), in the retina 24 h after IR and significantly reduced the GCL neuron death rate 7 days after reperfusion.
  
  
  CONCLUSIONS
  ATP-liposome treatment of IR-challenged neural tissues suppressed necrosis and correlated with a significantly reduced level of inflammation and retinal damage.
authors.affiliation: Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
authors.forename: Galina
authors.initials: G
authors.lastname: Dvoriantchikova
authors.forename: David J
authors.initials: DJ
authors.lastname: Barakat
authors.forename: Eleut
authors.initials: E
authors.lastname: Hernandez
authors.forename: Valery I
authors.initials: VI
authors.lastname: Shestopalov
authors.forename: Dmitry
authors.initials: D
authors.lastname: Ivanov
mesh_terms: D000255:Adenosine Triphosphate / Q000008:administration & dosage* / Q000494:pharmacology / Q000627:therapeutic use*; D000818:Animals; D001813:Blood-Retinal Barrier / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D016923:Cell Death / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D005947:Glucose / Q000172:deficiency; D007249:Inflammation / Q000150:complications / Q000188:drug therapy / Q000235:genetics / Q000473:pathology; D008081:Liposomes; D051379:Mice; D008810:Mice, Inbred C57BL; D010100:Oxygen; D015427:Reperfusion Injury / Q000150:complications / Q000188:drug therapy* / Q000517:prevention & control*; D012160:Retina / Q000187:drug effects / Q000473:pathology*; D012165:Retinal Ganglion Cells / Q000187:drug effects / Q000473:pathology / Q000648:ultrastructure; D055351:Retinal Neurons / Q000187:drug effects / Q000378:metabolism / Q000473:pathology
chemical_list: D008081:Liposomes; D000255:Adenosine Triphosphate; D005947:Glucose; D010100:Oxygen