Annual report 2009/10 - Human Fertilisation and Embryology Authority

Section 2
Work carried out during 2009
on issues identified previously
11
Somatic cells
Research into in vitro derived gametes has also
looked at using somatic cells, but there is less
research in this area compared to the use of
pluripotent stem cells. One study has shown that
fusing an ES cell with a somatic cell can reprogram
the genome into one that allows differentiation into
primordial germ cells in vitro 69 . These cells can then
undergo further differentiation into germ-like cells and
could provide personalised stem cells applicable to
regenerative medicine and fertility treatment.
In reviewing the technique of somatic cell haploidisation
(transformation of a diploid into a haploid cell) Nagy et
al (2008) 70 concluded that there were difficulties in
ensuring accurate chromosome segregation and
preventing epigenetic defects (defects that affect how
genes are expressed) in imprinted genes (genes which
are expressed differently according to which parent they
were inherited from) of the somatic cell nucleus. These
need to be overcome before the technique provides a
valid method for deriving gametes in vitro.
The HFEA’s view and outcomes
In September 2009 SCAAC considered a review of
advances in this field and concluded that no
published research had convincingly shown that hES
cells could be differentiated in vitro into mature
human sperm. The Committee thought it would take
between 5 to 10 years for gametes to be derived
entirely in vitro and that one of the main barriers was
incorrect imprinting. It was suggested that
transplanting gamete precursor cells to their normal
environment for the later stages of gamete maturation
could help, eg, putting sperm precursor cells into a
Sertoli cell (cells in the testes) environment or egg
precursors into a follicle cell environment.
The HFEA’s Horizon Scanning Panel expressed a
similar view in June 2009. They felt that there needed
to be more animal models, investigations into the
meiotic process and long term studies of offspring
resulting from in vitro derived gametes before the
technique could be considered successful or
potentially used in treatment.
The HFEA Executive and Licence Committees will
refer to relevant information and advice if they receive
licence applications from centres wishing to create
embryos using in vitro gametes, for research 71 .
Human Fertilisation & Embryology Authority
Scientific Horizon Scanning at the HFEA