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Assessing susceptibility to age-related macular degeneration with proteomic and genomic biomarkers.

Gu J, Pauer GJ, Yue X, Narendra U, Sturgill GM, Bena J, Gu X, Peachey NS, Salomon RG, Hagstrom SA, Crabb JW, Clinical Genomic and Proteomic AMD Study Gro - Mol. Cell Proteomics (2009)

Bottom Line: Mean CEP adduct and autoantibody levels were found to be elevated in AMD plasma by approximately 60 and approximately 30%, respectively.The results compellingly demonstrate higher mean CEP marker levels in AMD plasma over a broad age range.We conclude that CEP plasma biomarkers, particularly in combination with genomic markers, offer a potential early warning system for assessing susceptibility to this blinding, multifactorial disease.

View Article: PubMed Central - PubMed

Affiliation: Cole Eye Institute, Lerner Research Inst., Cleveland Clinic Foundation, 9500 Euclid Ave., Cleveland, OH 44195, USA.

ABSTRACT
Age-related macular degeneration (AMD) is a progressive disease and major cause of severe visual loss. Toward the discovery of tools for early identification of AMD susceptibility, we evaluated the combined predictive capability of proteomic and genomic AMD biomarkers. We quantified plasma carboxyethylpyrrole (CEP) oxidative protein modifications and CEP autoantibodies by ELISA in 916 AMD and 488 control donors. CEP adducts are uniquely generated from oxidation of docosahexaenoate-containing lipids that are abundant in the retina. Mean CEP adduct and autoantibody levels were found to be elevated in AMD plasma by approximately 60 and approximately 30%, respectively. The odds ratio for both CEP markers elevated was 3-fold greater or more in AMD than in control patients. Genotyping was performed for AMD risk polymorphisms associated with age-related maculopathy susceptibility 2 (ARMS2), high temperature requirement factor A1 (HTRA1), complement factor H, and complement C3, and the risk of AMD was predicted based on genotype alone or in combination with the CEP markers. The AMD risk predicted for those exhibiting elevated CEP markers and risk genotypes was 2-3-fold greater than the risk based on genotype alone. AMD donors carrying the ARMS2 and HTRA1 risk alleles were the most likely to exhibit elevated CEP markers. The results compellingly demonstrate higher mean CEP marker levels in AMD plasma over a broad age range. Receiver operating characteristic curves suggest that CEP markers alone can discriminate between AMD and control plasma donors with approximately 76% accuracy and in combination with genomic markers provide up to approximately 80% discrimination accuracy. Plasma CEP marker levels were altered slightly by several demographic and health factors that warrant further study. We conclude that CEP plasma biomarkers, particularly in combination with genomic markers, offer a potential early warning system for assessing susceptibility to this blinding, multifactorial disease.

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CEP adducts and autoantibodies are elevated in AMD plasma. CEP adduct concentrations (A) and autoantibody titers (B) quantified by ELISA from control (n = 488) and AMD (n = 916) plasma donors are shown with median (▵) results ± first and third quartiles (Q1, Q3) and mean (○) results ± S.D. indicated. p values (two-sided t test) were determined from log-transformed concentrations. These data are presented in Table I by category of AMD progression. Correlation between CEP adduct levels and autoantibody titers is shown for the control (C) and AMD (D) cohorts with horizontal and vertical dashed lines indicating median control values. Significantly more donors with both CEP markers elevated are apparent in AMD patients than in the controls (upper right quadrants in C and D).
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f1: CEP adducts and autoantibodies are elevated in AMD plasma. CEP adduct concentrations (A) and autoantibody titers (B) quantified by ELISA from control (n = 488) and AMD (n = 916) plasma donors are shown with median (▵) results ± first and third quartiles (Q1, Q3) and mean (○) results ± S.D. indicated. p values (two-sided t test) were determined from log-transformed concentrations. These data are presented in Table I by category of AMD progression. Correlation between CEP adduct levels and autoantibody titers is shown for the control (C) and AMD (D) cohorts with horizontal and vertical dashed lines indicating median control values. Significantly more donors with both CEP markers elevated are apparent in AMD patients than in the controls (upper right quadrants in C and D).

Mentions: Plasma samples from a total of 488 control subjects and 916 AMD subjects, including 177 with early stage dry AMD, 130 with midstage dry AMD, and 609 with advanced stage AMD, were analyzed by ELISA. The results (Fig. 1, A and B, and Table I) demonstrate higher mean levels of CEP adducts (∼1.6×) and autoantibody titers (∼1.3×) in AMD patients relative to control plasma. Comparison of log-transformed values confirmed the results and yielded p values <0.0001. Data from duplicate adduct and triplicate autoantibody measurements exhibited average intra-assay variability of ∼4% for adducts and ∼8% for autoantibodies. Interassay, day-to-day variability, as measured by IC50, averaged ∼25%. Western analysis of AMD and control plasma (n = 10 each) demonstrated that CEP adducts are associated with proteins and also supported higher levels of the adducts in AMD plasma (Fig. 2). Plasma from all categories of AMD progression, including early stage AMD, exhibited elevated mean levels of CEP adducts and autoantibodies with no significant difference between disease categories (Table I).


Assessing susceptibility to age-related macular degeneration with proteomic and genomic biomarkers.

Gu J, Pauer GJ, Yue X, Narendra U, Sturgill GM, Bena J, Gu X, Peachey NS, Salomon RG, Hagstrom SA, Crabb JW, Clinical Genomic and Proteomic AMD Study Gro - Mol. Cell Proteomics (2009)

CEP adducts and autoantibodies are elevated in AMD plasma. CEP adduct concentrations (A) and autoantibody titers (B) quantified by ELISA from control (n = 488) and AMD (n = 916) plasma donors are shown with median (▵) results ± first and third quartiles (Q1, Q3) and mean (○) results ± S.D. indicated. p values (two-sided t test) were determined from log-transformed concentrations. These data are presented in Table I by category of AMD progression. Correlation between CEP adduct levels and autoantibody titers is shown for the control (C) and AMD (D) cohorts with horizontal and vertical dashed lines indicating median control values. Significantly more donors with both CEP markers elevated are apparent in AMD patients than in the controls (upper right quadrants in C and D).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2690477&req=5

f1: CEP adducts and autoantibodies are elevated in AMD plasma. CEP adduct concentrations (A) and autoantibody titers (B) quantified by ELISA from control (n = 488) and AMD (n = 916) plasma donors are shown with median (▵) results ± first and third quartiles (Q1, Q3) and mean (○) results ± S.D. indicated. p values (two-sided t test) were determined from log-transformed concentrations. These data are presented in Table I by category of AMD progression. Correlation between CEP adduct levels and autoantibody titers is shown for the control (C) and AMD (D) cohorts with horizontal and vertical dashed lines indicating median control values. Significantly more donors with both CEP markers elevated are apparent in AMD patients than in the controls (upper right quadrants in C and D).
Mentions: Plasma samples from a total of 488 control subjects and 916 AMD subjects, including 177 with early stage dry AMD, 130 with midstage dry AMD, and 609 with advanced stage AMD, were analyzed by ELISA. The results (Fig. 1, A and B, and Table I) demonstrate higher mean levels of CEP adducts (∼1.6×) and autoantibody titers (∼1.3×) in AMD patients relative to control plasma. Comparison of log-transformed values confirmed the results and yielded p values <0.0001. Data from duplicate adduct and triplicate autoantibody measurements exhibited average intra-assay variability of ∼4% for adducts and ∼8% for autoantibodies. Interassay, day-to-day variability, as measured by IC50, averaged ∼25%. Western analysis of AMD and control plasma (n = 10 each) demonstrated that CEP adducts are associated with proteins and also supported higher levels of the adducts in AMD plasma (Fig. 2). Plasma from all categories of AMD progression, including early stage AMD, exhibited elevated mean levels of CEP adducts and autoantibodies with no significant difference between disease categories (Table I).

Bottom Line: Mean CEP adduct and autoantibody levels were found to be elevated in AMD plasma by approximately 60 and approximately 30%, respectively.The results compellingly demonstrate higher mean CEP marker levels in AMD plasma over a broad age range.We conclude that CEP plasma biomarkers, particularly in combination with genomic markers, offer a potential early warning system for assessing susceptibility to this blinding, multifactorial disease.

View Article: PubMed Central - PubMed

Affiliation: Cole Eye Institute, Lerner Research Inst., Cleveland Clinic Foundation, 9500 Euclid Ave., Cleveland, OH 44195, USA.

ABSTRACT
Age-related macular degeneration (AMD) is a progressive disease and major cause of severe visual loss. Toward the discovery of tools for early identification of AMD susceptibility, we evaluated the combined predictive capability of proteomic and genomic AMD biomarkers. We quantified plasma carboxyethylpyrrole (CEP) oxidative protein modifications and CEP autoantibodies by ELISA in 916 AMD and 488 control donors. CEP adducts are uniquely generated from oxidation of docosahexaenoate-containing lipids that are abundant in the retina. Mean CEP adduct and autoantibody levels were found to be elevated in AMD plasma by approximately 60 and approximately 30%, respectively. The odds ratio for both CEP markers elevated was 3-fold greater or more in AMD than in control patients. Genotyping was performed for AMD risk polymorphisms associated with age-related maculopathy susceptibility 2 (ARMS2), high temperature requirement factor A1 (HTRA1), complement factor H, and complement C3, and the risk of AMD was predicted based on genotype alone or in combination with the CEP markers. The AMD risk predicted for those exhibiting elevated CEP markers and risk genotypes was 2-3-fold greater than the risk based on genotype alone. AMD donors carrying the ARMS2 and HTRA1 risk alleles were the most likely to exhibit elevated CEP markers. The results compellingly demonstrate higher mean CEP marker levels in AMD plasma over a broad age range. Receiver operating characteristic curves suggest that CEP markers alone can discriminate between AMD and control plasma donors with approximately 76% accuracy and in combination with genomic markers provide up to approximately 80% discrimination accuracy. Plasma CEP marker levels were altered slightly by several demographic and health factors that warrant further study. We conclude that CEP plasma biomarkers, particularly in combination with genomic markers, offer a potential early warning system for assessing susceptibility to this blinding, multifactorial disease.

Show MeSH
Related in: MedlinePlus