title: Ultrastructure of internal limiting membrane removed during plasmin-assisted vitrectomy from eyes with diabetic macular edema.
abstract: OBJECTIVE
  To study the effect of autologous plasmin enzyme (APE) on the adhesion of the vitreous cortex to the internal limiting membrane (ILM) in eyes with diabetic macular edema.
  
  
  METHODS
  Nonrandomized, comparative, interventional case series.
  
  
  METHODS
  Ten eyes of 10 patients with diabetic macular edema without a posterior vitreous detachment (PVD), which were treated with APE as an adjunct to conventional pars plana vitrectomy, and 10 eyes of 9 patients without a PVD, which underwent pars plana vitrectomy without APE, were studied.
  
  
  METHODS
  In the APE group, 0.4 IU of APE was injected into the midvitreous cavity in 9 eyes, and 0.8 IU of APE in 1 eye. Thirty minutes after plasmin injection, the eyes underwent pars plana vitrectomy with ILM peeling. All eyes in the control group had conventional vitreous surgery with ILM peeling. The removed ILMs were investigated for the presence of vitreous and for ultrastructural differences by transmission and scanning electron microscopy.
  
  
  METHODS
  The status of the vitreous and induction of a PVD during surgery, and the presence of vitreous and ultrastructural differences of the removed ILM by transmission and scanning electron microscopy.
  
  
  RESULTS
  In APE-treated eyes, the degree of liquefaction of the vitreous was graded as high in 4 eyes. Spontaneous PVD occurred in 2 eyes, whereas core vitrectomy with a maximum vacuum of 100 mmHg induced a PVD in 2 additional eyes. In the control group, 8 eyes required suction with a maximum of 200 mmHg to induce the PVD. Scanning electron micrography of the removed ILM in the APE-treated eyes showed a smooth surface on the vitreous side in 8 eyes and only sparse collagen fibers in 2 eyes. Conversely, in the control group, dense vitreous fibers were found in 4 eyes, sparse collagen fibrils in 3 eyes, and a smooth retinal surface in 3 eyes.
  
  
  CONCLUSIONS
  These findings indicate that APE helps separate the vitreous hyaloid from the ILM surface and may be a useful adjunct to conventional vitreous surgery for diabetic macular edema.
authors.affiliation: Department of Ophthalmology, Nagoya University School of Medicine, Nagoya, Japan.
authors.forename: Tetsu
authors.initials: T
authors.lastname: Asami
authors.forename: Hiroko
authors.initials: H
authors.lastname: Terasaki
authors.forename: Shu
authors.initials: S
authors.lastname: Kachi
authors.forename: Makoto
authors.initials: M
authors.lastname: Nakamura
authors.forename: Keiko
authors.initials: K
authors.lastname: Yamamura
authors.forename: Toshitaka
authors.initials: T
authors.lastname: Nabeshima
authors.forename: Yozo
authors.initials: Y
authors.lastname: Miyake
mesh_terms: D000328:Adult; D000368:Aged; D001485:Basement Membrane / Q000601:surgery / Q000648:ultrastructure*; D003131:Combined Modality Therapy; D003930:Diabetic Retinopathy / Q000601:surgery*; D005260:Female; D005341:Fibrinolysin / Q000008:administration & dosage*; D005343:Fibrinolytic Agents / Q000008:administration & dosage*; D006801:Humans; D007267:Injections; D008269:Macular Edema / Q000601:surgery*; D008297:Male; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D014821:Vitrectomy / Q000379:methods*; D014822:Vitreous Body / Q000473:pathology
chemical_list: D005343:Fibrinolytic Agents; D005341:Fibrinolysin