Daniel Brison September 2014
1. Could you please highlight on your thrust areas of research in embryology and stem
cells?
Our work is currently focussed in several main areas:
a) Understanding the impact of IVF technologies on embryonic development. This
includes studies on human embryos of embryo metabolism as a marker of embryonic
health and a non-invasive method of embryo selection in clinical IVF and single
embryo gene expression (transcriptomic) studies to assess the impact of IVF
technologies such as embryo freezing and extended culture. We are using an animal
(mouse) model of in vitro implantation to look specifically at embryonic stress. We
are also using the horse as a model for understanding oocyte maturation and early
embryonic development. Funded by EU FP7 programme, RCOG Wellbeing of
Women and BBSRC.
b) understanding the impact of IVF on long term child health. We are currently
conducting an analysis of factors which affect birthweight in IVF, as a predictor of
long term disease. We are also carrying out a large data linkage project looking at
perinatal outcomes and growth of children born from IVF in the UK. Funded by EU
FP7 and MRC.
c) Deriving embryonic stem cells at clinical grade and using differentiated cells for
treatment of disease. We have derived 17 ES cell lines in Manchester from poor
quality discarded embryos or failed to fertilise oocytes which have been chemically
activated. 6 of these lines are clinical grade, derived under Good Manufacturing
Practice conditions in cleanroom conditions. We are currently working towards
making chondrocytes at clinical grade for repair of cartilage injuries and
osteoarthritis. Funded by MRC.
2. There are many criteria for embryo selection and numerous new devices and systems are
getting into clinical IVF lab..what do you think would be the future of this area and robust
methods of embryo selection.
The only significant advance in the last few years has been the development of timelapse systems.
These allow for undisturbed embryo culture, which appears to increase viability, while still allowing
excellent monitoring of embryo development. Whether the very detailed information will also allow
improved selection is still not clear, but even without this, timelapse has a role to play. Non-invasive
methods of assessing embryo metabolism are still a top priority, probably combined with timelapse.
We are continuing our work on amino acid profiling as an indicator of embryo health.
3. Many low resource settings need to depend on classical embryo selection methods. Out
of all such as pronuclear scoring, cleavage timings, cleavage stage scoring which is more
accurate for prediction?
Cleavage timings are the single most important parameter. Our group and others have shown
clearly that embryos which develop more slowly OR more quickly than the average, are less
viable than those which develop at the average timing.
4. There are a plethora of culture media in the field? Do you really think these cock tails
can support all the requirements of the embryos and what would be the epigenetic
consequences?
Commercial media have rigorous manufacturing quality control, which is a major
improvement from the days when embryology labs made media in house. However there is
still no consensus on the optimal composition of culture medium for human embryo
development, or even which commercially available medium is the best in terms of
supporting embryo viability, live birth rates and long term child health. It is likely that
different media will be more suitable for different endpoints, i.e. the medium which give a
higher pregnancy rate might well result in altered birthweights compared to other media.
Epigenetic effects can arise from media which have different compositions of methyl donors
or components which feed into the 1 carbon cycle, which therefore might alter DNA
methylation or cause other epigenetic effects in the embryo. Media which contain growth
factors also have the potential to alter embryonic and fetal growth. And finally the nutrient
composition can also determine the activity of various signalling pathways in the embryo
which might result in epigenetic changes.
5. Oil overlay is the mode of culture nowadays.. what are the deleterious effects of culture
oils-mineral/paraffin..and whether prolonged CO2 incubator incubation is safe for oils?
Oils can release toxic compounds into medium if stored incorrectly and in particular at high
temperature, or even at 37C for a prolonged period of time. See the UK ACE consensus
paper Bolton et al 2014 in Human Fertility for a review of medium in general and oil toxicity
in particular.
6. Do you recommend change over of culture media every 24 hours or continuous culture
I think both will work but we do not fully understand the consequences of the different
systems. Continuous culture risks accumulation of metabolic byproducts such as ammonia,
and depletion of essential nutrients. On the other hand changing media every 24h dilutes out
endogenous growth factors which might be very beneficial to development and also of course
disturbs the environment of the embryo.
7. Is microdroplet culture or 4-well (0.5mL) large volume culture safe regarding the
embryo molecular health?
No one knows what is truly safe, for the reasons described above. I tend to favour microdrop
culture as the evidence is animals is strong that this is beneficial, and there is also some
evidence in humans. But until long term health studies have been performed on children born
from the different systems we will not know whether any volume of media, or any other
parameter of IVF, is truly safe.
8. As an embryologist what are basic lab parameters need to be controlled to get a
successful outcome?
Gamete quality - reducing damage to oocytes from temperature, PH and osmolarity changes)
an reducing the impact of DNA damage in sperm by careful preparation.
Temperature and pH (CO2 level) must be rigorously controlled, although we must also be
aware that neither of these have ever been optimised for human embryo development. Even
though we do not know what temperature or pH is optimal, we must still make sure that they
are consistent and controlled.
Oxygen level I think it is very important to culture routinely in 5% O2.
Air quality HEPA f iltered air is very important to keep out particles which have been
shown to be toxic in many other areas of cell biology. Charcoal filtering to remove VOCs
may also be beneficial.
9. There are not many educational programs for embryology training..maximum PG
courses in UK only..How an embryology society can do better for certification of
embryologists based on UK model.
This is essential in order for embryologists to become competent and respected as a
profession and for patients to receive safe treatment. ESHRE has established certifications
for embryologists, and Alpha is involved in this area. Ultimately either healthcare
providers/government have to be prepared to pay for embryology training, as in the UK
where we have the NHS-based Scientists Training Programme, or private patients have to
pay.
10. Your advice to young embryologists
Make sure that you become as well trained as possible and seize every opportunity to gain
external qualifications.
Do not neglect research, the field has only come as far as it has through painstaking research
in the past, and future generations will not thank your generation if you neglect to develop
your field scientifically.
Always remember that as an embryologist your patients are the embryos which you grow in
the lab and the babies and children that result from them.