Platelet aggregates in VWF/ADAMTS13-deficient mice expressing mVWF/R1306Q or mVWF/V1316M. Blood smears prepared at day 7 after injection in VWF/ADAMTS13 double-deficient mice. (A) Quantitative analysis of platelet aggregates. Per mouse, 50 microscopic fields were analyzed (n = 6 for each mutant). Two types of platelet aggregates could be distinguished: < 10 platelets/aggregate or > 50 platelets/aggregates. No intermediate-sized platelet aggregates (10-50 platelets/aggregate) were observed. Data represent mean ± SE. Both mutants display a significant increase in the number of very large aggregates compared with their expression in VWF-deficient mice (P < .01). (B-C) Representative blood smear samples of mVWF/R1306Q (B) and mVWF/V1316M (C). Microscopy was performed with the use of a Axioimager-A1 microscope (Carl Zeiss) with a Plan-Apochromat 100×/1.4 oil-immersion objective (Carl Zeiss). Images were acquired with an Axiocam HRc camera (Carl Zeiss) and the Axiovision 4.5 software (Carl Zeiss).