Mice lacking PF4 have an attenuated VSMC inflammatory phenotype switch. (A) Representative image and (B) quantification of vessel wall area. Ligated carotid arteries were isolated 21 days after ligation, and the vessel wall area was measured at multiple levels of 200 µm apart and expressed as a ratio compared with internal control nonligated right carotid (n = 5 ± SD; *P < .01 vs WT). (C-D) PF4^−/− mice have less of a decline in VSMC differentiation markers in vivo. Carotids were isolated multiple days after ligation, and mRNA expression was quantified by qRT-PCR. (C) Cnn1 expression and (D) acta2 (n = 5 ± SD; *P < .01 vs WT).