title: Hyaluronan protection of corneal endothelial cells against extracellular histones after phacoemulsification.
abstract: OBJECTIVE
  To determine the effect of histones on corneal endothelial cells generated during cataract surgery.
  
  
  METHODS
  Kagoshima University Hospital, Kagoshima, Japan.
  
  
  METHODS
  Experimental study.
  
  
  METHODS
  Standard phacoemulsification was performed on enucleated pig eyes. Histones in the anterior segment of the eye were determined by immunohistochemistry. Cultured human corneal endothelial cells were exposed to histones for 18 hours, and cell viability was determined by 2-(2-methoxy-4-nitrophenyl)-3-(4-nitro-phenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt assay. The concentration of interleukin-6 (IL-6) in the culture medium of human corneal endothelial cells was measured using enzyme-linked immunosorbent assay. The effects of signal inhibitors U0126, SB203580, and SP600125 were evaluated. The protective effect of hyaluronan against histones was evaluated in human corneal endothelial cells with and without hyaluronan.
  
  
  RESULTS
  Cellular debris containing histones was observed in the anterior chamber of pig eyes after phacoemulsification. Exposure of human corneal endothelial cells to 50 μg/mL of histones or more led to cytotoxic effects. The IL-6 concentration was significantly increased dose dependently after exposure of human corneal endothelial cells to histones (P<.01). The histone-induced IL-6 production was significantly decreased by extracellular signal-regulated kinases 1/2 and p-38 mitogen-activated protein kinase inhibitors (P<.01). Co-incubation of hyaluronan and histones caused formation of histone aggregates, decreased the cytotoxic effects of the histones, and blocked the increase in IL-6 (P<.01).
  
  
  CONCLUSIONS
  Histones were released extracellularly during phacoemulsification and exposure of human corneal endothelial cells to histones increased the IL-6 secretion. The intraoperative use of hyaluronan may decrease the cytotoxic effects of histones released during cataract surgery.
  
  
  BACKGROUND
  No author has a financial or proprietary interest in any material or method mentioned.
authors.affiliation: From the Department of Ophthalmology (Kawano, Sakamoto), the Department of Laboratory and Vascular Medicine (Hashiguchi), and the Department of Systems Biology in Thromboregulation (Ito, Maruyama), Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, and Miyata Eye Hospitals (Miyata), Miyakonojyo, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kawano
authors.affiliation: From the Department of Ophthalmology (Kawano, Sakamoto), the Department of Laboratory and Vascular Medicine (Hashiguchi), and the Department of Systems Biology in Thromboregulation (Ito, Maruyama), Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, and Miyata Eye Hospitals (Miyata), Miyakonojyo, Japan. Electronic address: tsakamot@m3.kufm.kagoshima-u.ac.jp.
authors.forename: Taiji
authors.initials: T
authors.lastname: Sakamoto
authors.affiliation: From the Department of Ophthalmology (Kawano, Sakamoto), the Department of Laboratory and Vascular Medicine (Hashiguchi), and the Department of Systems Biology in Thromboregulation (Ito, Maruyama), Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, and Miyata Eye Hospitals (Miyata), Miyakonojyo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Ito
authors.affiliation: From the Department of Ophthalmology (Kawano, Sakamoto), the Department of Laboratory and Vascular Medicine (Hashiguchi), and the Department of Systems Biology in Thromboregulation (Ito, Maruyama), Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, and Miyata Eye Hospitals (Miyata), Miyakonojyo, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Miyata
authors.affiliation: From the Department of Ophthalmology (Kawano, Sakamoto), the Department of Laboratory and Vascular Medicine (Hashiguchi), and the Department of Systems Biology in Thromboregulation (Ito, Maruyama), Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, and Miyata Eye Hospitals (Miyata), Miyakonojyo, Japan.
authors.forename: Teruto
authors.initials: T
authors.lastname: Hashiguchi
authors.affiliation: From the Department of Ophthalmology (Kawano, Sakamoto), the Department of Laboratory and Vascular Medicine (Hashiguchi), and the Department of Systems Biology in Thromboregulation (Ito, Maruyama), Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, and Miyata Eye Hospitals (Miyata), Miyakonojyo, Japan.
authors.forename: Ikuro
authors.initials: I
authors.lastname: Maruyama
mesh_terms: D000818:Animals; D000867:Anterior Chamber / Q000378:metabolism; D002470:Cell Survival; D002478:Cells, Cultured; D019610:Cytoprotection / Q000187:drug effects; D004728:Endothelium, Corneal / Q000187:drug effects* / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D019084:Fluorescent Antibody Technique, Indirect; D006657:Histones / Q000378:metabolism / Q000633:toxicity*; D006801:Humans; D006820:Hyaluronic Acid / Q000494:pharmacology*; D015850:Interleukin-6 / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors; D018918:Phacoemulsification; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013552:Swine; D055675:Viscosupplements / Q000494:pharmacology*; D062826:Zonula Occludens-1 Protein / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors
chemical_list: D004791:Enzyme Inhibitors; D006657:Histones; C508600:IL6 protein, human; D015850:Interleukin-6; C569042:TJP1 protein, human; D055675:Viscosupplements; D062826:Zonula Occludens-1 Protein; D006820:Hyaluronic Acid; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D000254:Sodium-Potassium-Exchanging ATPase