The Stem Cell Network (SCN), established in 2001 as part of Canada's Networks of Centres of Excellence program, supports leading-edge projects that translate research discoveries into new and better treatments for millions of patients in Canada and around the world. Drew Lyall, executive director of the SCN, discusses the organization's mission and accomplishments.

This study investigated whether long-term repopulating hematopoietic stem cells (HSCs) can, in principle, be generated from embryonic stem cells without stroma cells or serum. It was shown that long-term multilineage engraftment could be accomplished in immunocompetent mice when HSCs were generated in serum-free medium without stroma cell support and when hypoxic conditions were used. These findings may ease the development of definitive, adult-type HSCs from pluripotent stem cells, entirely in vitro.

The expression of defined phenotypic profiles reported as cancer stem cell (CSC)-specific in human primary colorectal cancer (CRC) was analyzed in established CRC cell lines, and their correlation with CSC properties was evaluated. It was found that the expression of CD133 or the coexpression of CD166/CD44 or CD24/CD44 did not appear to reliably identify CSC populations in established CRC cell lines. These findings question the suitability of cell lines for the screening of CSC-specific therapies and underline the urgency of developing novel platforms for anticancer drug discovery.

This study used combined methods designed to expand the stem, progenitor, and precursor compartments to optimize the yield of cultured red blood cells. It was found that exposing CD34⁺ cells to a short pulse of cytokines favorable for erythroid differentiation prior to stem cell expansion followed by progenitor expansion produced the highest yield of erythroid cells. These new protocols obtained yields of red blood cells that were larger by an order of magnitude than those observed previously, and cells expressed a globin profile similar to that expected for the developmental age of the CD34⁺ cells.

This study examined the effects and signaling pathways associated with the actions of 1α,25-dihydroxyvitamin D₃ (VD₃) on dermal papilla cells (DPCs). Results suggest that VD₃ may promote functional differentiation of DPCs and be useful in preserving the hair follicle-inductive capacity of cultured DPCs for hair regeneration therapies.

Chronic obstructive pulmonary disease (COPD) is characterized by a progressive and not fully reversible airflow limitation caused by chronic small airway disease and lung parenchymal destruction. Clinically available drugs improve airflow obstruction and respiratory symptoms but cannot cure the disease. Recently, a method for the direct isolation of individual cell types from human lung has been developed, and fingerprints of each cell type in COPD lungs can be analyzed. Research using this technique combined with the recently discovered lung endogenous stem-progenitor populations will give a better understanding about the fate of COPD lung cells and provide a future for cell-based therapy to treat this intractable disease.

The precise spatial and temporal presentation of growth factors is critical for cartilage development, during which tightly controlled patterns of signals direct cell behavior and differentiation. This study elucidates the effects of varied conditions of transforming growth factor-β1-loaded microsphere incorporation on human mesenchymal stem cell chondrogenesis, demonstrating that both spatiotemporal growth factor presentation and donor variability influence chondrogenic differentiation within microsphere-incorporated cellular constructs.