Figure 2
From: WISP-1 drives bone formation at the expense of fat formation in human perivascular stem cells
WISP-1 expression in human PSC after FACS isolation and upon orthopaedic transplantation. (A) Fluorescence activated cell sorting (FACS) of human lipoaspirate was performed per established protocols to isolate perivascular stem/stromal cells (PSC). After isolation of CD31−CD45− non-endothelial/non-hematopoietic cells (not shown), PSC were further defined as adventitial progenitor cells (APC, CD34+CD146−) or microvascular pericytes (CD146+CD34−). (B) Quantitative RT-PCR for WISP1 transcripts, examined in passage one PSC or unpurified ASC (adipose-derived stromal cells) from the same patient sample. Performed in technical triplicate. (C–F) H&E appearance of rat spine fusion segments. (C,E) H&E appearance of PSC-treated spinal fusion segments with new bone formation, incorporation of demineralized bone matrix (DBM), and conspicuous bone-lining osteoblasts (arrowheads). (D,F) H&E appearance of control-treated spinal fusion segments, with little new bone formation, DBM particles without connections to each other and embedded in fibrous stroma, and inactive bone lining cells (arrowheads). (G–J) WISP-1 indirect immunohistochemical staining of PSC treated spine fusion segments. WISP-1 immunoreactivity appears brown, while nuclear Hematoxylin counterstain appears blue. (G,I) Strong WISP-1 immunoreactivity in bone lining cells among PSC treated samples. (H,J) Weak to intermediate WISP-1 immunoreactivity in inflammatory cells and stromal fibroblasts among control treated samples. *P < 0.05. Scale bars (parts C,D,G,H) 25 µm; Scale bar (parts E,F,I,J) 100 µm.
