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.
Department of Radiology, University of Texas Southwestern Medical Center, Dallas 75235-8592.
B A
BA
Berkowitz
N
N
Bansal
C A
CA
Wilson
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