Effect of the r-hu ADAMTS13 preparations on cerebral hemorrhage and tail bleeding time. (A) Representative unstained coronal brain sections of 1 mouse for each treatment show a lack of hemorrhage in r-hu ADAMTS13-treated mice (derived from HEK 293 and CHO cells). (B) Bleeding time measurements show highly increased bleeding in VWF^−/− mice compared with WT mice. All the VWF^−/− mice were cauterized at 900 seconds to stop bleeding. r-hu ADAMTS13-treated mice (5 hours) had a bleeding time comparable with WT mice (prepared in HEK cells) or prolonged bleeding time (prepared in CHO cells) but significantly shorter than the VWF^−/− mice. n = 8 each group.