Research Article

Disturbed Matrix Metalloproteinase Pathway in Both Age-Related Macular Degeneration and Alzheimer’s Disease

Figure 2

Components of the MMP Pathway in brain tissue. The MMP content of brain homogenates is shown in Gel A and the resulting profiles following centrifugation to obtain the supernatant fraction in Gel B. Altogether, 4 control and 4 AD brain samples were examined. HMW2 and pro-MMP9 were the predominant MMP species present in the homogenates with lower levels of HMW1. Pro-MMP2 was below the detection limit. Centrifugation to remove insoluble and membranous material resulting in the supernatant fraction showed a marked reduction in the level of HMW2 signifying that this species exists largely in the bound fraction. Supernatant fractions also demonstrated the presence of pro-MMP2. The molecular weights of MMP species present in brain were similar to those encountered in Bruch’s membrane of the eye. Densitometry was undertaken to calculate the percentage of bound MMP species using (1) in the manuscript. The gels demonstrate the presence of the MMP Pathway in brain tissue.