Neural progenitors of the postnatal and adult mouse forebrain retain the ability to self-replicate, form neurospheres, and undergo multipotent differentiation in vivo.

Somatic stem cells are reservoirs to replace lost cells or damaged tissue. Cells with neural stem cell (NSC) characteristics can be isolated from the postnatal mammalian brain into adulthood and expanded as neurospheres. We addressed the ability of these in vitro expanded putative NSCs to retain progenitor characteristics in vivo, in analogy to hematopoietic stem cells. When transplanted in utero, both postnatal and adult neural progenitors colonize host brains and contribute neurons and glia. In stark contrast to what has been reported when transplanted in postnatal hosts, epidermal growth factor-expanded cells also remain self-replicating and multipotent in vivo over many months and can be serially transplanted into multiple hosts. Surprisingly, embryonically transplanted NSCs remain in the neurogenic regions in adult hosts, where they express progenitor cell markers and continue to proliferate even after 6 months without tumor formation. These data indicate that spherogenic cells of the postnatal and adult mammalian brain retain their potential in vitro and in vivo throughout the life of the organism and beyond transplantation, which has important implications for cell replacement strategies.

SCNT-derived ESCs with mismatched mitochondria trigger an immune response in allogeneic hosts.

The generation of pluripotent stem cells by somatic cell nuclear transfer (SCNT) has recently been achieved in human cells and sparked new interest in this technology. The authors reporting this methodical breakthrough speculated that SCNT would allow the creation of patient-matched embryonic stem cells, even in patients with hereditary mitochondrial diseases. However, herein we show that mismatched mitochondria in nuclear-transfer-derived embryonic stem cells (NT-ESCs) possess alloantigenicity and are subject to immune rejection. In a murine transplantation setup, we demonstrate that allogeneic mitochondria in NT-ESCs, which are nucleus-identical to the recipient, may trigger an adaptive alloimmune response that impairs the survival of NT-ESC grafts. The immune response is adaptive, directed against mitochondrial content, and amenable for tolerance induction. Mitochondrial alloantigenicity should therefore be considered when developing therapeutic SCNT-based strategies.

How to build your own coronary anastomosis simulator from scratch.

OBJECTIVES: Gaining cardiac surgical competence is a complex, multifactorial process that may take years of experience and on-the-job training. It is critical to provide suitable educational opportunities to gain the necessary knowledge, judgment and skills. In response to the multitude of factors (e.g. European Working Time Directive) currently influencing cardiac surgical training, there have been concerted efforts to reform training practices. Simulation plays an increasingly important role in the educational process and serves to fill the most important gap in the current training model, i.e. operative exposure. Therefore, a contest has been written out for cardiac surgical trainees to construct their own coronary anastomosis simulator using everyday materials. METHODS: Cardiac surgical trainees were invited to construct their own coronary anastomosis simulator. An international jury of cardiac surgeons assessed the simulator and its presentation according to preset developmental criteria (low fidelity concept, innovative character, general presentation and description, general attractiveness to the scholar, ergonomical issues, perceived haptics, number of applicable components, transportability, ease of construction, repeatability and overall costs of the simulator). RESULTS: Six prototypes of simulators built by cardiac surgical trainees were generated. A general evaluation of each simulator prototype is provided according to the preset developmental criteria. CONCLUSIONS: All simulator prototypes have provided a considerable contribution to the field of surgical simulation. By designing simulator prototypes, the trainees have demonstrated their 'out of the box' thinking capability, which is of paramount importance for the development of future innovative surgical techniques and procedures. The Valladolid cardiac team coronary anastomosis simulator box was selected for the EACTS Ethicon Simulation Award 2011. This project will be mass produced and distributed to the participants of structured simulation sessions for coronary anastomoses.