Biomedical subjects

Shahar Cohen

Publications and source records attributed to Shahar Cohen.

3 recordsLinked to original sources

PubMed2006

Tissue engineering using human embryonic stem cells.

The possibility of using stem cells for tissue engineering has greatly encouraged scientists to design new platforms in the field of regenerative and reconstructive medicine. Stem cells have the ability to rejuvenate and repair damaged tissues and can be derived from both embryonic and adult sources. Among cell types suggested as a cell source for tissue engineering (TE), human embryonic stem cells (hESCs) are one of the most promising candidates. Isolated from the inner cell mass of preimplantation stage blastocysts, they possess the ability to differentiate into practically all adult cell types. In addition, their unlimited self-renewal capacity enables the generation of sufficient amount of cells for cell-based TE applications. Yet, several important challenges are to be addressed, such as the isolation of the desired cell type and gaining control over its differentiation and proliferation. Ultimately, combing scaffolding and bioactive stimuli, newly designed bioengineered constructs, could be assembled and applied to various clinical applications. Here we define the culture conditions for the derivation of connective tissue lineage progenitors, design strategies, and highlight the special considerations when using hESCs for TE applications.

Cell Culture Techniques↗

PubMed2006

Antibiotics reduce the growth rate and differentiation of embryonic stem cell cultures.

Embryonic stem cells (ESCs) are being investigated increasingly for their potential as a cell source for tissue engineering. Antibiotics are regularly used in ESC culture media to control contamination, although they can be cytotoxic and interfere with protein synthesis. Our aim was to examine the effects of the frequently used antibiotics gentamicin and combined penicillin and streptomycin on ESC culture using differentiation of murine ESC into type II pneumocytes as a model. Antibiotics reduced the expression of the specific marker for type II pneumocytes, SPC mRNA, by up to 60%. We also identified an adverse effect on the growth rate of differentiating embryoid bodies, causing a significant ( p < 0.05) reduction of up to 40%, and an increase in population doubling time of up to 48%. No contamination was seen in any of the cultures. Our findings suggest that the routine use of antibiotics in ESC culture should be avoided as it may reduce the efficiency of the culture system.

Animals↗

PubMed2006

Derivation of distal airway epithelium from human embryonic stem cells.

The pluripotency of embryonic stem cells (ESC) is offering new opportunities in tissue engineering and cell therapy. We have shown previously that alveolar epithelial cells, specifically type II pneumocytes, can be derived from murine ESC and hypothesized that a similar protocol could be used successfully on human ESC. Undifferentiated human ESC were induced to form embryoid bodies that were transferred into adherent culture conditions and grown in a medium designed for the maintenance of mature small airway epithelium. On inverted microscopy, the generated cells showed the cobblestone-like morphology of epithelium. The presence of surfactant protein C, a specific marker of type II pneumocytes, and its corresponding RNA were demonstrated by immunostaining and reverse transcription polymerase chain reaction, respectively. Electron microscopy revealed frequent cells with the typical ultrastructure of type II pneumocytes. This study provides evidence for in vitro induction of the differentiation from human ESC of alveolar type II cells, which have the potential for therapeutic use or construction of an in vitro model of human lung.

Animals↗