Alzheimer's peptide and serine proteinase inhibitors in glaucoma and exfoliation syndrome

The occurrence of inflammation with accompanying amyloid formation in pseudoexfoliation syndrome (PEX) resembles other inflammation-associated amyloidoses such as Alzheimer's disease (AD). To test whether the same proteins can be identified in PEX as in AD, we qualitatively analysed for Alzheimer's peptide (Abeta(1-42)) and the proteinase inhibitors alpha(1)-antichymotrypsin (ACT) and alpha(1)-antitrypsin (AAT) in the aqueous humor of patients with and without PEX material. Ninety aqueous humor samples were collected from patients in the age group between 46 and 95 during cataract surgery. Protein profiles in samples were analysed by electrophoresis followed by Western blotting. Blots were developed using specific antibodies against Abeta(1-42), AAT and ACT and peroxidase-conjugated IgG as a second antibody. At least one of the analysed proteins was found in 68.8% of 90 cases studied. Abeta(1-42) peptide was found in 22.2% of all cases, among them in seven cases with PEX (total n = 16) and in four with glaucoma (total n = 10). ACT and AAT were detected in 17.8 and 28.9% of all cases, respectively. In addition, female patients had significantly higher frequencies of detected ACT and AAT, compared to males. Abeta(1-42), ACT and AAT were also found in 17.6, 14.7 and 23.5% of the control (non-XF and non-glaucoma) samples (n = 68). Alzheimer's peptide is present in the aqueous humor of patients with PEX and glaucoma suggesting that these diseases may share common features in the biochemistry and etiologies with AD. The presence of Abeta and inflammation-associated proteins in aqueous from cataract cases without detectable PEX raises the possibility that these proteins may reflect early amyloid-related changes in the eye.