DKK1 and Alzheimer disease: In contrast, in the hippocampus of 3xTg-AD female mice, Dkk-1 levels were significantly greater in middle-aged compared with young animals (F1, 39 = 25.80, p < 0.0001) and with transgenic versus WT animals (F2, 39 = 17.81 p < 0.001) (Fig. 1A).