title: Biochemical analysis of the living human vitreous.
abstract: BACKGROUND
  To date, our understanding of the biochemical composition of the living human vitreous relies on extrapolations from animal or human post-mortem studies.
  
  
  METHODS
  This was a cross-sectional study of vitreous samples from 27 individuals scheduled for retinal surgery within a tertiary hospital. From each vitreous sample, the concentrations of sodium, potassium, chloride, calcium, magnesium, glucose, lactate, β- hydroxybutyrate, copper, zinc, selenium, iron, ferritin and transferrin and osmolality were measured. Perioperative serum samples were also obtained for comparison.
  
  
  RESULTS
  The following vitreous mean ± standard deviation (95% confidence interval of the mean) was observed for each analyte: sodium, 146.7 ± 3.3 (145.4-148.0) mmol/L; potassium, 5.73 ± 0.86 (5.39-6.08) mmol/L; chloride, 121.6 ± 2.6 (120.6-122.7) mmol/L; calcium, 1.128 ± 0.518 (0.923-1.333) mmol/L; magnesium, 0.900 ± 0.158 (0.838-0.962) mmol/L; glucose, 2.97 ± 0.98 (2.58-3.36) mmol/L; lactate, 3.97 ± 1.09 (3.54-4.40) mmol/L; osmolality, 289.5 ± 6.9 (286.6-292.5) mOsm/kg; BOHB, 0.0937 ± 0.0472 (0.0750-0.1124) mmol/L; copper, 0.519 ± 0.269 (0.412-0.625) µmol/L; zinc, 1.95 ± 1.09 (1.52-2.38) µmol/L; selenium, 0.1035 ± 0.0276 (0.0923-0.1146) µmol/L; iron, 3.11 ± 1.40 (2.56-3.66) µmol/L; ferritin, 19.5 ± 10.3 (15.5-23.6) µg/L; transferrin, 0.0878 ± 0.0526 (0.0670-0.1086) g/L. Vitreous biochemistry was not significantly different between male and female participants. Vitreous biochemistry was significantly different between non-diabetic and diabetic participants. Vitreous biochemistry was significantly different from the vitreous substitute BSS Plus (Alcon, USA). The vitreous extracted from living humans was markedly different from the commonly reported reference values obtained from animal studies.
  
  
  CONCLUSIONS
  The current data provide hitherto unavailable information about the biochemical composition of the living human vitreous.
authors.affiliation: University of Adelaide, Adelaide, South Australia, Australia. jkokavec@gmail.com.
authors.forename: Jan
authors.initials: J
authors.lastname: Kokavec
authors.affiliation: University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: San H
authors.initials: SH
authors.lastname: Min
authors.affiliation: University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: Mei H
authors.initials: MH
authors.lastname: Tan
authors.affiliation: University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: Jagjit S
authors.initials: JS
authors.lastname: Gilhotra
authors.affiliation: University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: Henry S
authors.initials: HS
authors.lastname: Newland
authors.affiliation: University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: Shane R
authors.initials: SR
authors.lastname: Durkin
authors.affiliation: University of Sydney, Sydney, New South Wales, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Grigg
authors.affiliation: University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Casson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000838:Anions / Q000378:metabolism*; D002412:Cations / Q000032:analysis*; D003430:Cross-Sectional Studies; D003922:Diabetes Mellitus, Type 1 / Q000150:complications*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications*; D019773:Epiretinal Membrane / Q000601:surgery; D005136:Eye Proteins / Q000032:analysis*; D005260:Female; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D009994:Osmolar Concentration; D012167:Retinal Perforations / Q000601:surgery; D014131:Trace Elements / Q000032:analysis*; D014821:Vitrectomy; D014822:Vitreous Body / Q000737:chemistry*
chemical_list: D000838:Anions; D002412:Cations; D005136:Eye Proteins; D014131:Trace Elements
keywords: ante-mortem; concentration; human; reference; vitreous