title: Endothelial differentiation of amniotic fluid-derived stem cells: synergism of biochemical and shear force stimuli.
abstract: Human amniotic fluid-derived stem (AFS) cells possess several advantages over embryonic and adult stem cells, as evidenced by expression of both types of stem cell markers and ability to differentiate into cells of all three germ layers. Herein, we examine endothelial differentiation of AFS cells in response to growth factors, shear force, and hypoxia. We isolated human AFS cells from amniotic fluid samples (1-4 cc/specimen) obtained from patients undergoing amniocentesis at 15-18 weeks of gestation (n = 10). Isolates maintained in nondifferentiating medium expressed the stem cell markers CD13, CD29, CD44, CD90, CD105, OCT-4, and SSEA-4 through passage 8. After 3 weeks of culture in endothelial growth media-2 (EGM-2), the stem cells exhibited an endothelial-like morphology, formed cord-like structures when plated on Matrigel, and uptook acetylated LDL/lectin. Additionally, mRNA and protein levels of CD31 and von Willebrand factor (vWF) significantly increased in response to culture in EGM-2, with further up-regulation when stimulated by physiological levels (12 dyne/cm(2)) of shear force. Culture in hypoxic conditions (5% O(2)) resulted in significant expression of vascular endothelial growth factor (VEGF) and placental growth factor (PGF) mRNA. This study suggests that AFS cells, isolated from minute amounts of amniotic fluid, acquire endothelial cell characteristics when stimulated by growth factors and shear force, and produce angiogenic factors (VEGF, PGF, and hepatocyte growth factor [HGF]) in response to hypoxia. Thus, amniotic fluid represents a rich source of mesenchymal stem cells potentially suitable for use in cardiovascular regenerative medicine.
authors.affiliation: Department of Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
authors.forename: Ping
authors.initials: P
authors.lastname: Zhang
authors.forename: Jason
authors.initials: J
authors.lastname: Baxter
authors.forename: Kateki
authors.initials: K
authors.lastname: Vinod
authors.forename: Thomas N
authors.initials: TN
authors.lastname: Tulenko
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Di Muzio
mesh_terms: D000649:Amniocentesis; D000653:Amniotic Fluid / Q000166:cytology* / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D002454:Cell Differentiation; D015687:Cell Hypoxia; D002469:Cell Separation; D002478:Cells, Cultured; D003470:Culture Media / Q000494:pharmacology; D042783:Endothelial Cells / Q000166:cytology* / Q000187:drug effects; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D017228:Hepatocyte Growth Factor / Q000235:genetics / Q000378:metabolism; D006801:Humans; D016130:Immunophenotyping; D010812:Physical Stimulation; D000072483:Placenta Growth Factor; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000235:genetics / Q000378:metabolism; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D013314:Stress, Mechanical; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism; D014841:von Willebrand Factor / Q000235:genetics / Q000378:metabolism
chemical_list: D015415:Biomarkers; D003470:Culture Media; C000608036:PGF protein, human; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D011257:Pregnancy Proteins; D042461:Vascular Endothelial Growth Factor A; D014841:von Willebrand Factor; D000072483:Placenta Growth Factor; D017228:Hepatocyte Growth Factor