Detection of Alzheimer peptides and chemokines in the aqueous humor.
OBJECTIVE
Alzheimer disease (AD) and age-related ocular diseases are characterized by inflammation and accumulation of insoluble proteins. We aimed to investigate the detectability and clinical relevance of a panel of AD-related markers, such as Alzheimer peptides and chemokines, in the aqueous humor (AH) samples taken from patients with cataract only, or cataract and 1 other ocular disease.


METHODS
The AH samples were obtained during cataract surgery from patients with cataract only (n=162), cataract and glaucoma (n=21), cataract and exfoliation (PEX) (n=31), cataract and macular degeneration (n=36), and cataract and diabetic retinopathy (n=16). The AD peptides (Aß1-42, Aß1-40, Aß1-38) and chemokines (eotaxin, eotaxin 3, interleukin [IL]-8, inducible protein-10, monocyte chemotactic protein [MCP]-1, MCP-4, macrophage-derived chemokine, macrophage inflammatory protein-1ß, thymus and activation-regulated chemokine) were quantified by using multiplex immunoassays.


RESULTS
The levels of the AH peptides (Aß1-38, Aß1-40, Aß1-42) did not differ between disease groups. Independently of disease group, the Aß1-38 levels correlated with Aß1-40 and Aß1-42 (p<0.001, n=277). Notably, the ratio Aß1-42 to Aß1-38 differed between PEX and macular degeneration (mean 95% confidence interval [CI] = 8.12 [11.3-3.99] vs 2.23 [2.67-0.52], p=0.003). Among chemokines examined, only MCP-1 and IL-8 were detected in about 90% to 46% of all analyzed (n=266) samples. Higher levels of AH IL-8 were found in the glaucoma group than in cataract only (p=0.011). Independently of disease group, a correlation was observed between AH MCP-1 and IL-8 (rho=0.275, p<0.001, n=266) and between MCP-1 and Aß1-40 (rho=0.239, p<0.001, n=266).


CONCLUSIONS
Our findings highlight pathologic similarities between AD and eye diseases, and show the potential of modern technologies to detect AD biomarkers in age-related eye diseases.
Janciauskiene
Sabina
S
Department of Pulmonology, Hannover Medical School, Hannover, Germany. Janciauskiene.Sabina@mh-hannover.de
Westin
Karin
K
Grip
Olof
O
Krakau
Torsten
T
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000378:metabolism*; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D001082:Aqueous Humor / Q000378:metabolism*; D002386:Cataract / Q000378:metabolism; D002387:Cataract Extraction; D018925:Chemokines / Q000378:metabolism*; D017889:Exfoliation Syndrome / Q000378:metabolism; D005260:Female; D005901:Glaucoma / Q000378:metabolism; D006801:Humans; D007118:Immunoassay; D008268:Macular Degeneration / Q000378:metabolism; D008297:Male; D008875:Middle Aged
D016229:Amyloid beta-Peptides; D018925:Chemokines