Travis J. Block

Background: Umbilical cord blood (UCB) not only contains hematopoietic stem cells (HSCs), but also non-hematopoietic stem cells (NHSCs) that are able to differentiate into a number of distinct cell types. Based on studies published to date, the frequency of NHSCs in UCB is believed to be very low. However, the isolation of these cells is primarily based on their adhesion to tissue culture plastic surfaces.Methods and results: In the current study, we demonstrate that this approach overlooks some of the extremely immature NHSCs because they lack the ability to adhere to plastic. Using a native extracellular matrix (ECM), produced by bone marrow (BM) stromal cells, the majority of the UCB-NHSCs attached within 4 h. The colony-forming unit fibroblast frequency of these cells was 1.5 × 10⁴/10⁸mononuclear cells, which is at least 4000-fold greater than previously reported for UCB-NHSCs. The phenotype of these cells was fibroblast-like and different from those obtained by plastic adhesion; they formed embryonic body-like clusters that were OCT4-positive and expressed other human embryonic stem cell-related markers. Importantly, when implanted subcutaneously for 8 weeks into immunocompromised mice, these ECM-adherent and expanded NHSCs generated three germ layer-derived human tissues including muscle, fat, blood vessel, bone, gland, and nerve. Moreover, injection of these cells into muscle damaged by cryoinjury significantly accelerated muscle regeneration.Conclusions: These results indicate that UCB may be a virtually unlimited source of NHSCs when combined with isolation and expansion on ECM. NHSCs may be a practical alternative to embryonic stem cells for a number of therapeutic applications.

Science outreach improves science literacy among the public and communication skills of scientists. However, despite the array of well-documented benefits, robust outreach efforts are often absent from communities which stand to benefit the most from these initiatives. Here, we introduce “Science Fiesta,” a graduate student-led outreach initiative which utilizes cultural traditions of South Texas as a vehicle to establish self-sustaining interactions between scientists and their local community. Event assessment surveys indicated that attendees found the event both fun and educational. At the same time, graduate students who organized the event and participated in outreach reported that they strengthened a variety of professional skills important for their future careers. More importantly, the event had a substantial positive impact on enthusiasm for science outreach. Both public attendees and graduate students reported that they were likely to participate in future science outreach events, even though a majority of both groups had not been previously involved in outreach efforts. Science Fiesta is a model for a highly effective graduate student-led outreach initiative that is capable of 1) improving public scientific literacy, 2) reinforcing graduate education and career development and 3) creating a culture of science engagement within local communities.

Science outreach improves science literacy among the public and communication skills of scientists. However, despite the array of well-documented benefits, robust outreach efforts are often absent from communities which stand to benefit the most from these initiatives. Here, we introduce “Science Fiesta,” a graduate student-led outreach initiative which utilizes cultural traditions of South Texas as a vehicle to establish self-sustaining interactions between scientists and their local community. Event assessment surveys indicated that attendees found the event both fun and educational. At the same time, graduate students who organized the event and participated in outreach reported that they strengthened a variety of professional skills important for their future careers. More importantly, the event had a substantial positive impact on enthusiasm for science outreach. Both public attendees and graduate students reported that they were likely to participate in future science outreach events, even though a majority of both groups had not been previously involved in outreach efforts. Science Fiesta is a model for a highly effective graduate student-led outreach initiative that is capable of 1) improving public scientific literacy, 2) reinforcing graduate education and career development and 3) creating a culture of science engagement within local communities.

Introduction: Bone marrow-derived mesenchymal stem cells (BM-MSCs) for clinical use should not be grown in media containing fetal bovine serum (FBS), because of serum-related concerns over biosafety and batch-to-batch variability. Previously, we described the preparation and use of a cell-free native extracellular matrix (ECM) made by bone marrow cells (BM-ECM) which preserves stem cell properties and enhances proliferation. Here, we compare colony-forming ability and differentiation of MSCs cultured on BM-ECM with a commercially available matrix (CELLstart™) and tissue culture plastic (TCP) under serum-free conditions. Methods: Primary MSCs from freshly isolated bone marrow-derived mononuclear cells or passaged MSCs (P1) were grown in serum-containing (SCM) or serum-free (SFM) media on BM-ECM, CELLstart™, or TCP substrates. Proliferation, cell composition (phenotype), colony-forming unit replication, and bone morphogenetic protein-2 (BMP-2) responsiveness were compared among cells maintained on the three substrates. Results: Proliferation of primary BM-MSCs was significantly higher in SCM than SFM, irrespectively of culture substrate, suggesting that the expansion of these cells requires SCM. In contrast, passaged cells cultured on BM-ECM or CELLstart™ in SFM proliferated to nearly the same extent as cells in SCM. However, morphologically, those on BM-ECM were smaller and more aligned, slender, and long. Cells grown for 7 days on BM-ECM in SFM were 20–40 % more positive for MSC surface markers than cells cultured on CELLstart™. Cells cultured on TCP contained the smallest number of cells positive for MSC markers. MSC colony-forming ability in SFM, as measured by CFU-fibroblasts, was increased 10-, 9-, and 2-fold when P1 cells were cultured on BM-ECM, CELLstart™, and TCP, respectively. Significantly, CFU-adipocyte and -osteoblast replication of cells grown on BM-ECM was dramatically increased over those on CELLstart™ (2X) and TCP (4-7X). BM-MSCs, cultured in SFM and treated with BMP-2, retained their differentiation capacity better on BM-ECM than on either of the other two substrates. Conclusions: Our findings indicate that BM-ECM provides a unique microenvironment that supports the colony-forming ability of MSCs in SFM and preserves their stem cell properties. The establishment of a robust culture system, combining native tissue-specific ECM and SFM, provides an avenue for preparing significant numbers of potent MSCs for cell-based therapies in patients.