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Metabolomic analysis of human vitreous humor differentiates ocular inflammatory disease.

Young SP, Nessim M, Falciani F, Trevino V, Banerjee SP, Scott RA, Murray PI, Wallace GR - Mol. Vis. (2009)

Bottom Line: A genetic algorithm coupled with multivariate classification identified a small number of spectral components that showed clear discrimination between LIU and CU samples with sensitivity and specificity >90%.Assignment of specific resonances indicated that some metabolites involved in the arginase pathway were significantly more abundant in LIU than CU.Collectively the data demonstrates the efficacy of metabolomic analysis to distinguish between ocular inflammatory diseases.

View Article: PubMed Central - PubMed

Affiliation: Department of Rheumatology, University of Birmingham, Birmingham, UK.

ABSTRACT

Purpose: Vitreoretinal disorders lack specific biomarkers that define either disease type or response to treatment. We have used NMR-based metabolomic analysis of human vitreous humor to assess the applicability of this approach to the study of ocular disease.

Methods: Vitreous samples from patients with a range of vitreoretinal disorders were subjected to high-resolution (1)H-nuclear magnetic resonance spectroscopy (NMR). Good quality spectra were derived from the vitreous samples, and the profiles were analyzed by three different methods.

Results: Principal component analysis (PCA) showed a wide dispersal of the different clinical conditions. Partial least squares discriminant analysis (PLS-DA) was used to define differences between lens-induced uveitis (LIU) and chronic uveitis (CU) and could distinguish between these conditions with a sensitivity of 78% and specificity of 85%. A genetic algorithm coupled with multivariate classification identified a small number of spectral components that showed clear discrimination between LIU and CU samples with sensitivity and specificity >90%. Assignment of specific resonances indicated that some metabolites involved in the arginase pathway were significantly more abundant in LIU than CU.

Conclusion: The discrimination we observed based on PCA, PLS-DA, and multivariate variable selection analysis of the NMR spectra suggests that a complex mix of metabolites are present in vitreous fluid of different uveitic conditions as a result of the disease process. Collectively the data demonstrates the efficacy of metabolomic analysis to distinguish between ocular inflammatory diseases.

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Related in: MedlinePlus

A typical 1D 1H NMR spectrum of vitreous eye fluid from a uveitis patient. A: The original spectrum labeled to show the regions in which some typical biofluid components are known to give rise to resonances. The spectrum has been scaled to highlight the detail; the inset is the unscaled whole spectrum. B: A data reduced spectrum in which the region between 4.5 and 5 ppm has been deleted so that any contribution from residual water signal is eliminated. This spectrum has been “binned” into 0.005 Hz regions.
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f1: A typical 1D 1H NMR spectrum of vitreous eye fluid from a uveitis patient. A: The original spectrum labeled to show the regions in which some typical biofluid components are known to give rise to resonances. The spectrum has been scaled to highlight the detail; the inset is the unscaled whole spectrum. B: A data reduced spectrum in which the region between 4.5 and 5 ppm has been deleted so that any contribution from residual water signal is eliminated. This spectrum has been “binned” into 0.005 Hz regions.

Mentions: NMR spectroscopy is a relatively insensitive method usually requiring samples to contain concentrations of target molecules in the high micromolar range. Our first concern was whether useful NMR spectra could be derived from the small vitreous humor samples available using a highly sensitive NMR instrument equipped with a cyroprobe that is able to minimize electronic noise in the system and thus maximize its sensitivity to the small NMR signals from dilute samples. Even with the small volumes available it was possible to acquire well-resolved spectra (Figure 1A). Acquisition time for each spectrum was relatively short, of the order of 10 min, making it possible to process a set of samples in a reasonable time. Although we used an NMR pulse sequence aimed at minimizing the detrimental effects of proteins present in the samples, which tend to produce amorphous humps within the spectra, this seemed to be less of a problem with the vitreous samples than with serum. The concentration of proteins in vitreous is considerably less than that in serum and this made a contribution to the quality of the spectra derived from these small volumes.


Metabolomic analysis of human vitreous humor differentiates ocular inflammatory disease.

Young SP, Nessim M, Falciani F, Trevino V, Banerjee SP, Scott RA, Murray PI, Wallace GR - Mol. Vis. (2009)

A typical 1D 1H NMR spectrum of vitreous eye fluid from a uveitis patient. A: The original spectrum labeled to show the regions in which some typical biofluid components are known to give rise to resonances. The spectrum has been scaled to highlight the detail; the inset is the unscaled whole spectrum. B: A data reduced spectrum in which the region between 4.5 and 5 ppm has been deleted so that any contribution from residual water signal is eliminated. This spectrum has been “binned” into 0.005 Hz regions.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2697460&req=5

f1: A typical 1D 1H NMR spectrum of vitreous eye fluid from a uveitis patient. A: The original spectrum labeled to show the regions in which some typical biofluid components are known to give rise to resonances. The spectrum has been scaled to highlight the detail; the inset is the unscaled whole spectrum. B: A data reduced spectrum in which the region between 4.5 and 5 ppm has been deleted so that any contribution from residual water signal is eliminated. This spectrum has been “binned” into 0.005 Hz regions.
Mentions: NMR spectroscopy is a relatively insensitive method usually requiring samples to contain concentrations of target molecules in the high micromolar range. Our first concern was whether useful NMR spectra could be derived from the small vitreous humor samples available using a highly sensitive NMR instrument equipped with a cyroprobe that is able to minimize electronic noise in the system and thus maximize its sensitivity to the small NMR signals from dilute samples. Even with the small volumes available it was possible to acquire well-resolved spectra (Figure 1A). Acquisition time for each spectrum was relatively short, of the order of 10 min, making it possible to process a set of samples in a reasonable time. Although we used an NMR pulse sequence aimed at minimizing the detrimental effects of proteins present in the samples, which tend to produce amorphous humps within the spectra, this seemed to be less of a problem with the vitreous samples than with serum. The concentration of proteins in vitreous is considerably less than that in serum and this made a contribution to the quality of the spectra derived from these small volumes.

Bottom Line: A genetic algorithm coupled with multivariate classification identified a small number of spectral components that showed clear discrimination between LIU and CU samples with sensitivity and specificity >90%.Assignment of specific resonances indicated that some metabolites involved in the arginase pathway were significantly more abundant in LIU than CU.Collectively the data demonstrates the efficacy of metabolomic analysis to distinguish between ocular inflammatory diseases.

View Article: PubMed Central - PubMed

Affiliation: Department of Rheumatology, University of Birmingham, Birmingham, UK.

ABSTRACT

Purpose: Vitreoretinal disorders lack specific biomarkers that define either disease type or response to treatment. We have used NMR-based metabolomic analysis of human vitreous humor to assess the applicability of this approach to the study of ocular disease.

Methods: Vitreous samples from patients with a range of vitreoretinal disorders were subjected to high-resolution (1)H-nuclear magnetic resonance spectroscopy (NMR). Good quality spectra were derived from the vitreous samples, and the profiles were analyzed by three different methods.

Results: Principal component analysis (PCA) showed a wide dispersal of the different clinical conditions. Partial least squares discriminant analysis (PLS-DA) was used to define differences between lens-induced uveitis (LIU) and chronic uveitis (CU) and could distinguish between these conditions with a sensitivity of 78% and specificity of 85%. A genetic algorithm coupled with multivariate classification identified a small number of spectral components that showed clear discrimination between LIU and CU samples with sensitivity and specificity >90%. Assignment of specific resonances indicated that some metabolites involved in the arginase pathway were significantly more abundant in LIU than CU.

Conclusion: The discrimination we observed based on PCA, PLS-DA, and multivariate variable selection analysis of the NMR spectra suggests that a complex mix of metabolites are present in vitreous fluid of different uveitic conditions as a result of the disease process. Collectively the data demonstrates the efficacy of metabolomic analysis to distinguish between ocular inflammatory diseases.

Show MeSH
Related in: MedlinePlus