Infertility treatments such as in-vitro fertilization make use of the same process
but do it in a laboratory so that implantation can be controlled
in the case of someone being infertile.
In this case, hormonal treatments trigger multiple eggs to develop
and they are harvested laparoscopically.
The egg donor who may or may not be the same person
who will carry the pregnancy to term
then will have the eggs removed, put into a dish
and they will be fertilized with donor spermatozoa at that point.
These newly fertilized eggs will then be kept alive
and several will be followed until about the 8 cell stage,
at which point they can be implanted or frozen.
In the case of male infertility,
sperm if they are viable in the testes can be gathered from there
or from a little further down into the epididymis and so forth
and then injected directly into the reproductive tract
or used in the process of in-vitro fertilization.
Now in terms of problems that can go wrong in this process,
the big one to know is ectopic pregnancy.
Generally, an oocyte that fails to enter the oviduct will not be fertilized
and will simply degenerate out in the peritoneal lining
and this really doesn't create too many problems.
However, if an oocyte is fertilized but fails to implant in the uterus,
it can cause several problems.
Most commonly, you can have a tubal pregnancy
where an implantation occurs within the oviduct.
This commonly occurs in the ampulla, roughly where fertilization usually takes place.
Thereafter, the isthmus of the oviduct near the uterus
is a common site as is the fimbria, out on the end of the oviduct.
If the egg actually migrates into the peritoneum and is fertilized,
the most common site for that ectopic pregnancy to develop
is between the rectum and the uterus,
otherwise known as the rectouterine pouch of Douglas.
So those ectopic pregnancies are a medical emergency
because they will grow to a certain point
and induce vessel formation in the tissues where they implant,
but those tissues are not the uterus
and they are not capable of sustaining the developing fetus
to the point where it can be viable and will likely cause hemorrhage
as the fetus becomes nonviable and dies.
In this case, surgical abortion is the most common treatment
to get rid off of this life threatening condition.
The promise of stem cell therapy and therapeutics is very, very real
and what we want to know about stem cell treatments is that these stem cells
can produce multiple organs and tissues that can be of use
in dealing with degenerative diseases or other disease states.
The early zygote and morula produce cells
that can become anything or associated with the fetus,
be it the developing embryo or its support tissues such as the placenta.
These cells are called totipotent, meaning they can become anything.
Cells of the, little bit further on in development,
of the inner cell mass of the morula
or the embryoblast of the blastocyst are called pluripotent;
meaning they can become any tissue in the embryonic and fetal body,
but they cannot necessarily differentiate into cells of the placenta
or other extra embryonic tissues.
These pluripotent cells can be cultured in such a way that they receive molecular signals
that allow them to move and become tissues or organs of the body
that can then be transplanted.
The major problem with transplantation now is that we have the risk of immune rejection
should there not be a good match between the donor and the recipient.
What I like to call the holy grail of the stem cell research
is how we can culture pluripotent cells
of our own body to then differentiate into any group of cells
or become totipotent
and differentiate into any organ or any tissue that can then be used as an autotransplant.
There have been some successes on this front
and even though we've not necessarily got totipotent cells
available from the differentiated cells in the human body,
some cells have actually been made multipotent;
meaning they can't turn into any tissue in the human body
but they can differentiate into one of several tissues cultured,
harvested and then transplanted.
Thank you very much for your attention.