FIG. 1.

MVs derived from Alde-Low EPCs can improve the angiogenic activity of Alde-High EPCs. (A) MVs derived from Alde-Low EPCs were isolated by FACS after centrifugation. (B) MVs derived from Alde-Low EPCs were stained with PKH-26 (red fluorescent) and transfected to cells. After 24 h, the cells were observed under fluorescence microscope. Scale bar: 200 μm. (C) The analysis of mRNA levels of the indicated genes in MVs and parental cells by an RT-PCR. c, Alde-Low EPCs; m, MVs derived from Alde-Low EPCs. (D) CXCR4, VEGF, SDF1, ColIV, and VCAM-1 mRNA expression were analyzed in Alde-High EPCs that were transfected with MVs (white bar) in comparison to Alde-High EPCs (black bar) under normoxic conditions. The expression level detected in Alde-High EPCs was normalized to a value of 1 as the standard for each factor. *P < 0.05, **P < 0.01. (E) Skin incisions were created on the dorsal skin of mice. PBS alone, Alde-Low EPCs, Alde-High EPCs, or Alde-High EPCs with MVs were injected to the mice. The effects of the EPCs in the recovery from ischemia were analyzed on day 7 after surgery. (F) The necrotic regions in the four different types of mice (n = 3 in each) were measured. Note that the area of necrosis in the mice that were injected with Alde-High EPCs with MVs was similar to that in mice that were injected with Alde-Low EPCs. *P < 0.05, **P < 0.01. EPCs, endothelial progenitor cells; FACS, fluorescence-activated cell sorting; mRNA, messenger RNA; MVs, microvesicles; PBS, phosphate-buffered saline; RT-PCR, reverse transcription-polymerase chain reaction; VEGF, vascular endothelial growth factor. Color images available online at www.liebertpub.com/scd