ACTA1 and cerebral cavernous malformation: In contrast, the staining of mesenchymal cell markers FSP-1 and α-SMA were both weak in control cells treated with CCM (Fig. 4); in cells treated with albumin + CCM, the staining of both FSP-1 and α-SMA was much stronger than that in control cells; in cells treated with albumin + SCM, however, the staining of both α-SMA and FSP-1 was similar to the levels in control cells.