04/18/23 1Herhaling titel van presentatie

HUMAN EMBRYONIC STEM CELLS AND ITS POSSIBLE APPLICATIONS

IN GENETICS

Professor ANDRE VAN STEIRTEGHEMKoninklijke Academie voor Geneeskunde van België

Emeritus Professor Vrije Universiteit Brussel

Honorary Consultant Centre for Reproductive Medicine, Universitair Ziekenhuis Brussel

Editor-in-Chief Human Reproduction

FEAM 2007

Outline lecture

• Introduction• Legal and ethical framework• Derivation and differentiation of hESC lines• hESC lines from genetically abnormal

embryos• European registry of hESC lines • Conclusions• Acknowledgments

Introduction

• Definition of human Embryonic Stem Cells (hESC)• Derived from preimplantation embryo• Proliferate without differentiation for a long

period• Have potential of stable differentiation

towards three embryonic layers and all types of cells of an embryo and an adult individual

Derivation of a hES line

Opinion poll after first publication

ESC for therapy IVF for infertility

USA 68% 81%

UK 62% 62%

Australia 72% 86%

Great “hope” for stem cell therapy

Outline lecture

• Introduction• Legal and ethical framework• Derivation and differentiation of hESC lines• hESC lines from genetically abnormal

embryos• European registry of hESC lines • Conclusions• Acknowledgments

Legal and ethical issues

• Great variety of legal framework regarding hESC• Liberal law: UK, Belgium• Restrictive law: Germany, Italy• Intermediate law: France, The Netherlands

• Particular situation in the USA• Approval of ethical committee is always

required (local or national)

hES CELLS IN BELGIUM

• Belgian law on the protection of human

embryo in-vitro allows research on IVF-ICSI-

PGD research embryos

• If necessary embryos can be made for

research

• Stem cell research and therapeutic cloning is

allowed

Regulations in European Member States Regarding Human Embryonic Stem Cell Research (July 2003)

Policy EU Member States

No specific legislation regarding human embryo research Luxembourg, Portugal

Allowing for the creation of human embryos for stem cell procurement by law

Belgium, United Kingdom

Prohibition of the procurement of embryonic stem cells from human embryos

Austria, Spain, France, Ireland, Italy

Prohibition of the procurement of embryonic stem cells from human embryos but allowing by law for the importation of human embryonic stem cell lines

Germany

Allowing for the procurement of human embryonic stem cells from supernumerary embryos by law

Belgium, Denmark, Finland, Greece, Netherlands, Sweden, United Kingdom

Prohibition of the creation of human embryos for research purposes and for the procurement of stem cells by law or by ratification of the Convention of the Council of Europe on Human Rights and Biomedicine signed in Oviedo on April 4, 1997

Austria, Denmark, Germany, Spain, Finland, France, Greece, Ireland, Netherlands, Portugal

Outline lecture

• Introduction• Legal and ethical framework• Derivation and differentiation of hESC

lines• hESC lines from genetically abnormal

embryos• European registry of hESC lines • Conclusions• Acknowledgments

Where do human embryonic stem cells come from?

• ICM of expanded blastocysts

• Put in culture on mouse embryonic

fibroblasts

• Culture medium contains fetal calf

serum/serum replacement and BFGF

Derivation of hESC

5-day old plated ICM

Culture of hESC

ES cell colonies, > 30 passages

Propagation by cutting

Propagation of hESC cells

Totipotency of hESC: teratoma in vivo

Teratoma VUB01 Chondroid tissue

Primitive bronchial epithelium Primitive nerve fibers

Totipotency of hESC: embryoid bodies in vitro

• Clumps of hESC in suspension

• No MEF, no BFGF• Spontaneously differentiate

to all three germ layers• Classic method used for

differentiation in the mouse•Plate the cells•Look for the interesting

cells

Directed differentiation: in vivo situation

Blastocyst

ICM

Trophoblast

Epiblast

Hypoblast

Embryonicepiblast

Amnionicectoderm

Embryonicectoderm

Primitivestreak

Embryonicendoderm

Embryonicmesoderm

Outline lecture

• Introduction• Legal and ethical framework• Derivation and differentiation of hESC lines• hESC lines from genetically abnormal

embryos• European registry of hESC lines • Conclusions• Acknowledgments

• PGD introduced in 1990 can be carried out for an increasing number of monogenic and chromosomal disorders for couples with a high risk of an affected child

• Affected embryos will not be transferred and may be used to derive human embryonic stem cell lines if there are no legal restrictions

• Belgium law (May 2003) on the protection of human embryo in vitro allows embryo research and derivation of hESC lines

• Different hES cell lines have different gene

expression characteristics comparative

studies are required before considering

clinical use

• Derivation of most cell lines using MEF

only for in vitro research

• Feeder-free conditions reported

(Klimanskaya et al. Lancet 365: 1636, 2005)

• Sofar at Vrije Universiteit Brussel 14 well

established hESC lines

• Four from genetically normal embryos

• Ten from genetically abnormal PGD embryos:

myotonic dystrophy, carrier cystic fibrosis,

Huntington disease, Marfan syndrome, fascio-

scapulo-humeral disease, spinocerebellar ataxia,

Fragile-X syndrome (2 lines), adult polykystic

kidney disease and bare lymphocyte syndrome

• Genetically normal and affected hES cell lines can be compared

• DM1, CF and HD common genetic diseases without treatment

• Model for human diseases: hES cell lines can be unlimited source of specific cell types involved in pathology of the disease eg CNS neurons in HD

• Study of mechanisms of dynamic mutations caused by unstable triplet repeats using hES cell lines from DM1 and HD

• CF line with F508 and 5T pathogenesis of CBAVD

• Each of the genetic diseases are very rare (< 5 births per 10,000) maximum of 200 000 affected patients per disease in European Union

• However, there are about 7000 different genetic diseases the number of affected patients is high (estimate in Europe of 25-30 million)

• Pharmacotherapy for genetic diseases is almost non-existing; validation of new compounds is currently almost impossible

• Search for biomarkers associated with the expression of mutated genes

• Functional genomic studies can be

carried out to search for the molecular

mechanisms of the genetic diseases

• Using chemical data bases it may be

possible to discover molecules with

therapeutic potential

Outline lecture

• Introduction• Legal and ethical framework• Derivation and differentiation of hESC lines• hESC lines from genetically abnormal

embryos• European registry of hESC lines • Conclusions• Acknowledgments

• European Commission announced creation of a European registry for human embryonic stem cell research

• To promote coordination of stem cell research in Europe

• Detailed information on all embryonic stem cell lines available in Europe

• Registry available to public via internet: characteristics, contact data, interesting developments (clinical trials and hESC lines from Eu-funded projects

• Advisory Board, Steering Committee and independent Ethics Advisory Board

• Stem cell research funded by Sixth and Seventh Framework Programme

Outline lecture

• Introduction• Legal and ethical framework• Derivation and differentiation of hESC lines• hESC lines from genetically abnormal

embryos• European registry of hESC lines • Conclusions• Acknowledgments

Outline lecture

• Introduction• Legal and ethical framework• Derivation and differentiation of hESC lines• hESC lines from genetically abnormal

embryos• European registry of hESC lines • Conclusions• Acknowledgments

Collaborators

Prof. Dr. I. LiebaersProf. Dr. K. SermonProf. Dr. J. VanderelstProf. Dr. P. DevroeyDr. M. De RyckeDr. H. Van de Velde

Stem cell team: Claudia SpitsIleana MateizelNele De TemmermanUrielle UllmannMieke GeensRogier SchellensLindsay Van Haute