Figure 3.

Effects of APP expression, age, and plaque load on CAA. (A) Quantification of CAA grade indicates that homozygous mice (+/+) have significantly more vascular amyloid than hemizygous mice (+/−) within the same age-range. No vascular amyloid is observed in wild-type (wt) mice. Error bars indicate SEM. (B) CAA development is age-dependent, as shown for the hemizygous mice with ages ranging from 14–21 months. (C) Because the development of parenchymal amyloid (plaques) is also age-dependent, we used partial correlation to examine the relationship between amyloid plaque load and CAA grade with age held constant. Individual CAA grade and plaque load values were adjusted by a linear formula inverse to their respective age regression lines (age held constant at the mean of 18.3 months). The resulting graph (C) and partial correlation statistics (r = 0.21) failed to indicate a significant relationship between plaques and CAA.