Use of platelet lysate prompts pluripotent stem cells towards differentiation. (A) Optical microscopy of pluripotent stem cells (PSC) cultured during 4 days in either standard growth condition (control) or platelet lysate-supplemented medium (PL). Cells gain cytoplasm and differentiation zones are observed. (B) mRNA levels of OCT-4 and NANOG in PSC cultured during 4 days in control (CM) or PL, assessed by quantitative PCR. A rapid decline in pluripotent transcription factors is seen (*P <0.05). (C) Fluorescence microscopy of 4′,6-diamidino-2-phenylindole (DAPI), OCT-4 and NANOG in PSC cultured as mentioned above. A faint stain for OCT-4 is observed, whereas no expression of NANOG is found.