Non-invasive measurement of steady-state vitreous lactate concentration.
The cellular events leading to the proliferation of new preretinal blood vessels into the vitreous are unknown. It has been hypothesized that a metabolic trigger, such as increased lactate concentration, induces ambient growth factors to initiate this neovascularization. However, this hypothesis has not been tested in vivo because non-invasive methods for measuring vitreous lactate concentration have not been available. In this study, we identified lactate as the dominant resonance in normal rabbit vitreous using a water-suppressed, localized proton NMR method; negligible spectral contamination from lipid, alanine and threonine was demonstrated. The steady-state vitreous lactate concentration in vivo was 11.3 +/- 4 mM (mean +/- SD, n = 7 eyes) which was not statistically different (p = 0.498) to the enzymatically determined lactate content in vitreous from a parallel group of animals [12.1 +/- 0.6 mM (n = 6 eyes)]. Non-invasive measurement of steady-state vitreous lactate concentration using localized proton NMR represents the necessary first step in understanding the role of lactate in neovascularization.
Berkowitz
B A
BA
Department of Radiology, University of Texas Southwestern Medical Center, Dallas 75235-8592.
Bansal
N
N
Wilson
C A
CA
D000818:Animals; D001834:Body Water / Q000378:metabolism; D005260:Female; D007773:Lactates / Q000378:metabolism*; D019344:Lactic Acid; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D011817:Rabbits; D012680:Sensitivity and Specificity; D014822:Vitreous Body / Q000378:metabolism*
D007773:Lactates; D019344:Lactic Acid