Current cell culture techniques may not replicate aspects of the embryonic microenvironment, making it difficult to scale-up and generate large numbers of differentiated cells from pluripotent stem cells (PSCs). To overcome this obstacle, Drs. Peter Zandstra and Molly Shoichet have developed a new method that uses a modified version of agarose to immobilize vascular endothelial growth factor A (VEGFA), thereby directing PSCs to develop into blood progenitor cells.

In results published in Biomaterials on August 2, 2010, the researchers reported that coumarin-sulphide was the best substrate for immobilizing VEGFA, a signalling growth factor that regulates angiogenesis by promoting proliferation, migration and the sprouting of endothelial cells. Temporal control of VEGFA has been shown to be an important determinant of hematopoietic stem cell fate. Subsequent analyses showed that cells grown on the immobilized-VEGFA agarose substrate were 8- and 75- times more efficient in upregulating mesodermal markers (T+VEGFR2+) than cells grown in control media containing soluble VEGF. Importantly, use of the immobilized VEGFA substrate led to the generation of blood progenitor cells by day 7 in serum free media.

Cells grown in three-dimensional hydrogels mimic physiological conditions better than cells grown on regular layered substrates, and immobilizing specific growth factors may result in increased local protein concentration and improved PSC differentiation. Development of this hydrogel system provides a framework to mimic the native stem cell niche, influence PSC differentiation and improve our understanding of mechanisms that are involved in stem cell regulation. Furthermore, it provides an important technique for robust and effective differentiation of PSCs towards target cell types.

The use of vascular endothelial growth factor functionalized agarose to guide pluripotent stem cell aggregates toward blood progenitor cells. Rahman N, Purpura KA, Wylie RG, Zandstra PW, Shoichet MS. Biomaterials. 2010 August 2. [Abstract]

The American Association for Thoracic Surgery (AATS) has chosen Dr. Richard Weisel to receive their Scientific Achievement Award for his “visionary work and commitment to scientific education”. This prestigious award was established to recognize individuals who have made extraordinary scientific contributions in the field of thoracic surgery.

Congratulations to Dr. Weisel!

The McEwen Centre’s Second Annual “Celebrate Science” Day will be held on September 23, 2010. The theme of this year’s event is The Stem Cell Healthcare Revolution and You, and will focus on how innovative research in stem cell medicine is impacting Canadians today, and into the future.

Special events will include a public symposium in the afternoon, featuring talks from several McEwen Centre scientists as well as Canadians who have experienced real benefits from stem cell research. Science Fair exhibits illustrating the important advancements in stem cell research taking place at the McEwen Centre will also be on display. The day’s events will conclude with a reception and fundraising dinner, featuring special guest Canadian singer/songwriter Jann Arden.