In this issue

Xeno-free isolation and expansion of mesenchymal stem cells from the umbilical cord

Simões et al., Biotechnol. J. 2013, 8, 448–458.

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Mesenchymal stem cells (MSC) have great potential in the areas of cellular therapy and tissue engineering. The ability to obtain clinically meaningful numbers of human MSC while avoiding poorly defined reagents, such as fetal bovine serum, for isolation and ex-vivo expansion of MSCs remains a major challenge. In this issue, Simoes et al. (Technical University of Lisbon) report isolation of human MSC from the umbilical cord (UC) matrix using serum-/xeno-free culture media with 100% success rate. Compared to MSC from adult sources, UC-derived cells showed similar immunophenotype and multilineage differentiation ability, while displaying a higher expansion potential. The UC, which is routinely discarded upon birth, is thus an attractive source of early stage MSC with increased proliferative capacity

Stem cell migration – is stiffer better?

Vincent et al., Biotechnol. J. 2013, 8, 472–484.

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Mesenchymal stem cells (MSC) are involved in tissue repair at sites of injury. One of the homing factors that guide MSCs to these sites is the rigidity of the environment. Fibrotic lesions are naturally stiffer than healthy tissue, which creates a stiffness gradient that cells can sense. In this issue, Vincent et al. (University of California, USA) utilize polyacrylamide hydrogels with varying stiffness gradient strengths to demonstrate that the migration speed of human MSC up a stiffness gradient correlates with gradient strength rather than gradient range. Directed migration was drastically reduced when cells were treated with pharmacological agents that affect the cytoskeleton, suggesting coordination between the cytoskeleton and cell-generated forces. Understanding the cytoskeletal-based mechanisms behind biased cell migration is of clinical importance in the context of fibrotic diseases

Screening inorganic coatings for stem cell control

Choi and Murphy, Biotechnol. J. 2013, 8, 496–501.

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Mineral coatings are important components of many medical implants, as they can be designed to improve biocompatibility, to control local drug delivery, or even to stimulate new tissue formation by stem cells. Coating characteristics ranging from nanometer-scale morphology to dissolution rate can influence stem cell behavior in complex and unpredictable ways. In this issue, Choi and Murphy (University of Wisconsin, USA) use an enhanced high-throughput approach to efficiently screen for stem cell interactions with a library of mineral coatings. They demonstrate that mineral coating properties can significantly influence human stem cell expansion and differentiation. Their results suggest also that coating morphology on the micro- and nano-scale regulates stem cell growth and differentiation, and is likely to be a critical variable in the design of medical devices and bone tissue engineering scaffolds