Study shows muscle tissue grown from stem cells can repair heart damage

May, 2012 — A Japanese research team has developed a promising new treatment for heart failure by growing sheets of new heart muscle tissue from stem cells. When implanted in damaged rat hearts, the bioengineered tissue improved heart function.

Differentiation Efficiency of Induced Pluripotent Stem Cells Depends on the Number of Reprogramming Factors

From Stem Cells
By Stuart P. Atkinson

Multiple studies in the last few years have attempted the production of induced pluripotent stem cells (iPSCs) with a reduced set of reprogramming factors (from OCT4, SOX2, KLF4, MYC or OCT4, SOX2, LIN28 and NANOG) in order that the process becomes streamlined in the hope that this may reduce potential mutation load in the resultant cells. This has been accomplished by many groups, resulting in iPSC formation at a lower efficiency, but the effect of a reduction in reprogramming factors on the subsequent differentiation capacity has not been fully explored. A report in the March edition of Stem Cells, from the laboratory of Alexander Storch now addresses this point, and finds that a reduction of reprogramming factors not only reduces reprogramming efficiency but negatively affects differentiation (Löhle et al).

Elevated Coding Mutation Rate During the Reprogramming of Human Somatic Cells into Induced Pluripotent Stem Cells

From Stem Cells
By Stuart P. Atkinson

Recent studies in the field of induced pluripotent stem cells (iPSCs) through karyotypic (Taapken et al) and meta-analysis of gene expression data (Mayshar et al) have revealed aneuploidy, and also copy number analysis has detected large-scale sub-chromosomal aberrations (Laurent­­ et al and Martins-Taylor et al) that arise upon prolonged passaging. Further, it is known that mutations not present in the parental cell of reprogramming arise during the reprogramming process (Gore et al and Hussein et al), but the proportion of mutations in iPSCs acquired due to the reprogramming process is unknown.

In Vivo Generation of Neural Tumors from Neoplastic Pluripotent Stem Cells Models Early Human Pediatric Brain Tumor Formation

From Stem Cells
By Stuart P. Atkinson

Several recent studies (Ben-Porath et al, Somervaille et al and Wong et al) have identified ESC-like gene expression patterns in a variety of malignant tumors suggesting a molecular relationship between aggressive cancers and pluripotency. However, the molecular determinants of such a link have yet to be uncovered. Now using normal human embryonic stem cells (hESCs) and transformed hESCs (t-hESCs), which have acquired features of neoplastic progression, including enhanced self-renewal, proliferation and tumor-initiating cell capacity, and aberrant neural lineage specification (Werbowetski-Ogilvie TE et al. 2009), researchers from the group of Mickie Bhatia at the McMaster University, Hamilton, Ontario, have shown that derived neural progenitors from the transformed cells possess brain tumor-initiating cell capacity, thereby providing a model system to investigate initiation and progression of primitive human neural cancers, such as medulloblastoma that are difficult to assess using somatic sources (Werbowetski-Ogilvie et al 2012).

Stem Cell-Seeded Cardiopatch Could Deliver Results for Damaged Hearts

Durham, NC (March 2012) – A new type of stem cell-seeded patch has shown promising results in promoting healing after a heart attack, according to a study released today in the journal STEM CELLS Translational Medicine.

Stem Cell Scientists Boost Cell Survival in Adipose Tissue Transplantations

Durham, NC (March 2012) – A new study by a team of researchers at Tor Vergata University of Rome reveals a way to improve the long-term results in patients receiving fat grafts to correct soft tissue defects. Their work was released today in STEM CELLS Translational Medicine.

Control of Ground-state Pluripotency by Allelic Regulation of Nanog

From Nature
By Stuart P. Atkinson

The attainment of pluripotency during development has been linked to genome-wide epigenetic changes, such as DNA methylation and histone modifications, and also to the expression of key genes, such as Oct4 and Nanog (Chambers et al, Mitsui et al, Nichols et al and Reik). However, details on how such epigenetic changes affect key pluripotency-associated gene expression in pre-and post-implantation embryo’s and also in embryonic stem cells (ESCs) are relatively scarce. Now, in a report published in Nature, Miyanari and Torres-Padilla from the IGBMC, Universitaire de Strasbourg, France, Nanog has been shown to undergo a switch from mono-allelic expression in early pre-implantation embryos to bi-allelic expression during the transition towards ground-state pluripotency in the naive epiblast of the late blastocyst, controlled in part by histone modifications.

Attenuation of extrinsic signaling reveals the importance of matrix remodeling on maintenance of ESC self-renewal

From PNAS
By Stuart P. Atkinson

The mammalian embryo requires properly controlled extrinsic signalling for normal development. Autocrine and paracrine signals are also important in blastocyst-derived embryonic stem cell (ESC) self-renewal (Bendall et al), growth (Mittal and Voldman) and differentiation (Kunath et al and Peerani et al). Understanding the range of cell-secreted factors that mediate autocrine and paracrine signalling which are important for self-renewal would enhance our comprehension of early embryonic fate choices and for exploiting the therapeutic potential of these cells, but only a few factors, which are saturated in culture by exogenous addition, are actually known. To this end Przybylaa and Voldman from the Hospital for Sick Children, University of Toronto, have studied mouse ESC (mESC) growth using a microfluidic perfusion system, in which cell-secreted diffusible molecules can be removed by flow, establishing culture conditions in which signaling pathways are not obscured by cell-secreted signals.