Cellule souche (médecine)

Les cellules souches sont des cellules indifférenciées capables de s’autorenouveler et de se différencier en cellules spécialisées. Leur potentiel de différenciation dépend de leur capacité (cellules souches unipotentes, multipotentes ou pluripotentes) et de leur origine (cellules souches fœtales, embryonnaires ou adultes). Les cellules souches ont été décrites dans les années 60 notamment par les chercheurs James Till et Ernest McCulloch. Leur utilisation en clinique dans le cadre de la greffe de moelle osseuse a débuté avant même leur identification formelle dès les années 50. Les cellules souches possèdent un potentiel très prometteur pour de nombreuses autres applications cliniques. En particulier, les cellules souches pluripotentes pourraient être utilisées en thérapie cellulaire dans l'objectif de régénérer des tissus mais aussi en pharmacologie afin d'identifier de nouveaux médicaments. Elles font l'objet de recherches cliniques et fondamentales très actives. Cependant, l'uti

Isolation and characterisation of a porcine cardiac adherent cell population from heart biopsies

Christelle Hasselmann

Cardiac diseases represent the major cause of mortality in the Western world. The discovery of the promising human Cardiac Adherent Proliferating (CAP) cells for a potential cardiac cell therapy by the Tissue Engineering group induced the need of a reliable animal model. The aim of the project is to identify a porcine cardiac cell population having similar characteristics as human CAP cells. Here a protocol for isolating cells from porcine heart biopsies have been established, as well as the in vitro expansion method. Additionally, the characterization of those expanded porcine cardiac cells was accomplished by growth kinetics study, FACS analysis, multilineage potential and myogenic induction assays. In this study we identified a not yet described porcine cardiac adherent cell population directly isolated from biopsies within the inner right ventricle. With almost

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expanded cells after 30 days in culture, porcine cardiac cells present a high rate of proliferation in vitro. Porcine cardiac cells maintain a swirl-like pattern until 5-6 days in culture, and become fibroblast-like with a parallel organization when confluent. FACS analysis indicated that porcine cells are mainly CD90+ in opposite to human CAP cells. Both species show a similar CD45- and CD44+ profile. The multilineage assay showed no histological differentiation into fat, bone and cartilage on porcine cardiac cells like on human CAP cells. However gene expression analysis on porcine cardiac cells indicated that aP2 was upregulated in population undergoing an adipogenic induction, as well as osteopontine expression in osteogenic induction population. Porcine cardiac cell myogenic induction potential was tested on C2C12 myogenic mouse cells. The mouse cells differentiated in muscle in vitro thanks to the influence of those cardiac cells. Both cell populations have similar characteristics and the main distinction is the different CD90 expression profile. Those results encourage to realise additional studies, to confirm that those isolated cells could be a reliable model of human CAP cells.

2009

Innovative strategy of corneal epithelium regeneration using fabricated soft contact lens containing cavities for stem cells transplantation

Julien Graber

Transplantation of donor cornea is widely performed with a high success rate to treat patients with impaired corneal transparency. However the limited number of donors has led scientists to search for new technologies and treatments, including stem cell therapies. We have developed a device that permits the transplantation of stem cells onto the cornea in order to regenerate a functional epithelium. It is shaped as a contact lens and it possesses cavities in its internal portion that are filled with a cell suspension. The device is used as a carrier to transfer the cells onto the cornea. To test and validate our approach we created an ex vivo system to perform long-term organotypic culture on the cornea of enucleated pig eyes. We seeded corneal epithelial cells onto pig stromas. We demonstrate that 30'000 donor cells can regenerate an entire epithelium in organotypic culture conditions. By using our culture system no living animals were required during the conception and evaluation of the device. We performed preliminary in vivo trials on rabbits, which showed promising results. We aim to create a user-friendly and low cost ocular surface reconstruction procedure that will be an alternative to current treatments. The advantages of our strategy are that it will not require cell culture or tissue preparation, as is the case for usual tissue-based grafts. Hopefully this technique could extend to clinical studies and could one day be used as an ocular surface reconstruction procedure.

EPFL2014

Isolation and characterisation of a porcine cardiac adherent cell population from heart biopsies

Christelle Hasselmann

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2009

Microfluidic engineering of stem cell microenvironment

Isolation and characterisation of a porcine cardiac adherent cell population from heart biopsies

Innovative strategy of corneal epithelium regeneration using fabricated soft contact lens containing cavities for stem cells transplantation

Microfluidic engineering of stem cell microenvironment

Isolation and characterisation of a porcine cardiac adherent cell population from heart biopsies

Innovative strategy of corneal epithelium regeneration using fabricated soft contact lens containing cavities for stem cells transplantation