title: Proteomic analysis of vitreous biopsy techniques.
abstract: OBJECTIVE
  To compare vitreous biopsy methods using analysis platforms used in proteomics biomarker discovery.
  
  
  METHODS
  Vitreous biopsies from 10 eyes were collected sequentially using a 23-gauge needle and a 23-gauge vitreous cutter instrument. Paired specimens were evaluated by UV absorbance spectroscopy, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and liquid chromatography tandem mass spectrometry (LC-MS/MS).
  
  
  RESULTS
  The total protein concentration obtained with a needle and vitrectomy instrument biopsy averaged 1.10 mg/mL (standard error of the mean = 0.35) and 1.13 mg/mL (standard error of the mean = 0.25), respectively. In eight eyes with low or medium viscidity, there was a very high correlation (R = 0.934) between the biopsy methods. When data from 2 eyes with high viscidity vitreous were included, the correlation was reduced (R = 0.704). The molecular weight protein sodium dodecyl sulfate-polyacrylamide gel electrophoresis profiles of paired needle and vitreous cutter samples were similar, except for a minority of pairs with single band intensity variance. Using LC-MS/MS, equivalent peptides were identified with similar frequencies (R ≥ 0.90) in paired samples.
  
  
  CONCLUSIONS
  Proteins and peptides collected from vitreous needle biopsies are nearly equivalent to those obtained from a vitreous cutter instrument. This study suggests both techniques may be used for most proteomic and biomarker discovery studies of vitreoretinal diseases, although a minority of proteins and peptides may differ in concentration.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA, USA.
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Skeie
authors.forename: Eric N
authors.initials: EN
authors.lastname: Brown
authors.forename: Harryl D
authors.initials: HD
authors.lastname: Martinez
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Russell
authors.forename: Emily S
authors.initials: ES
authors.lastname: Birkholz
authors.forename: James C
authors.initials: JC
authors.lastname: Folk
authors.forename: H Culver
authors.initials: HC
authors.lastname: Boldt
authors.forename: Karen M
authors.initials: KM
authors.lastname: Gehrs
authors.forename: Edwin M
authors.initials: EM
authors.lastname: Stone
authors.forename: Michael E
authors.initials: ME
authors.lastname: Wright
authors.forename: Vinit B
authors.initials: VB
authors.lastname: Mahajan
mesh_terms: D000293:Adolescent; D000368:Aged; D015415:Biomarkers / Q000032:analysis*; D001706:Biopsy / Q000295:instrumentation / Q000379:methods*; D002853:Chromatography, Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D005128:Eye Diseases / Q000175:diagnosis; D005136:Eye Proteins / Q000032:analysis*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D040901:Proteomics; D013056:Spectrophotometry, Ultraviolet; D053719:Tandem Mass Spectrometry; D014821:Vitrectomy / Q000295:instrumentation; D014822:Vitreous Body / Q000737:chemistry*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D005136:Eye Proteins