The efficacy of the photodynamic therapy (PDT) against Acanthamoeba keratitis

• Project/Area Number: 25861635
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Ophthalmology
• Research Institution: Ehime University
• Principal Investigator: OKA Naoko 愛媛大学, 医学部附属病院, 医員 (20403818)
• Project Period (FY): 2013-04-01 – 2015-03-31
• Project Status: Completed (Fiscal Year 2014)
• Budget Amount: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000); Fiscal Year 2014: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000); Fiscal Year 2013: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
• Keywords: アカントアメーバ / 光線力学療法 / PDT / メチレンブルー / 角膜感染症 / 真菌 / 光感受性物質

Outline of Final Research Achievements

We sought to elucidate the efficacy of the photodynamic therapy (PDT) against Acanthamoeba keratitis using methylene blue (MB) which is a photosensitizer. In vitro, Antiacanthamoeba activity was evaluated by checking the respiratory activity of the amoeba. MB-PDT suppressed the respiratory activity of trophozoites in an MB-concentration-dependent manner. Also anti-amoebic effect of MB-PDT was observed to be light dose dependent. Besides, we examined the toxicity of PDT treatment in vivo using C57BL/6 mouse corneas with epithelial defects, and found that MB-PDT did not cause any appreciable damage to the cornea. Thus, we conclude that PDT treatment would produce minimal toxicity in vivo. Although our results show that MB-PDT is efficacious in vitro, these results may not correlate with in vivo efficacy; therefore, further animal studies are under way to test the in vivo efficacy of this treatment for Acanthamoeba.

Research Products

• [Journal Article] Pseudomonas aeruginosa MucD protease mediate keratitis by inhibition of neutrophil recruitment and bacterial survival. (2014)
  • Author(s): Mochizuki, Y., Suzuki, T., Oka, N., Zhang, Y., Hayashi, Y., Hayashi, N., Gotoh, N., and Ohashi, Y.
  • Journal Title: Invest. Ophthalmol. Vis. Sci. Volume: 55 Issue: 1 Pages: 240-246
  • DOI: 10.1167/iovs.13-13151
  • Peer Reviewed / Open Access
• [Journal Article] Genotypic analysis of Pseudomonas aeruginosa isolated from ocular infection (2014)
  • Author(s): Yamaguchi S, Suzuki T, Kobayashi T, Oka N, Ishikawa E, Shinomiya H, Ohashi Y
  • Journal Title: J Infect Chemother Volume: 20 Issue: 7 Pages: 407-11
  • DOI: 10.1016/j.jiac.2014.02.007
  • Peer Reviewed
• [Presentation] Virulence factors in Pseudomonas aeruginosa isolates associated with keratitis (2015)
  • Author(s): Naoko Oka, Takashi Suzuki, Naoki Hayashi, Naomasa Gotoh, Yuichi Ohashi
  • Organizer: Asia Association for Research in Vision and Ophthalmology Annual Meeting (ARVO)
  • Place of Presentation: パシフィコ横浜
  • Year and Date: 2015-02-17
• [Presentation] 緑膿菌角膜炎における臨床所見と分離株の鞭毛運動能の関連について (2014)
  • Author(s): 岡奈央子、鈴木崇、林直樹、後藤直正、大橋裕一
  • Organizer: 第51回日本眼感染症学会
  • Place of Presentation: 東京国際フォーラム
  • Year and Date: 2014-07-04
• [Presentation] Distribution of glycoprotein B and UL144 genotypes in immunocompetent patients with cytomegalovirus endotheliitis and iridocyclitis (2014)
  • Author(s): Naoko Oka, Takashi Suzuki, Tomoyuki Inoue, Takeshi Kobayashi, Kozaburo Hayashi, Yuichi Ohashi
  • Organizer: Association for Research in Vision and Ophthalmology Annual Meeting (ARVO)
  • Place of Presentation: Orlando, USA
  • Year and Date: 2014-05-06