History and Development of HRT Flashcards
Discovery of spermatozoa: Anton Van Leeuwenoek
Father of microbiology, first microbiologist.
First to observe and describe single-celled organism
(animalcules)…microorganisms, muscle fibres, bacteria, capillaries and
spermatozoa.
Drew the first sketches of sperm
John Hunter (Artificial Insemination)
Appointed as surgeon at St George’s in 1768.
He advised a patient with severe hypospadias to collect the semen which
escaped during coitus in a warmed syringe and inject the sample into the
vagina. A successful pregnancy resulted.
Define Hypospadias
Hypospadias opening
of the urethra
develops abnormally,
usually on the
underside of the penis.
Abnormal closure of
the urethral fold over
the genital groove.
Walter Heape (embryo transfer)
Walter Heape Cambridge University 1891
Transferred 4 cell embryos from the uterine tubes of Angora rabbits and placed them into the tubes of a recently mated Belgian hare.
2 Angora rabbits (and 4 Belgians) in the resulting litter.
General anaesthetic and the embryos transferred on the point of forceps…they were not transferred to any kind of media.
First to take pre-implantation embryos and transfer them to a gestational carrier without affecting their development.
Oestrogens & Sex Steroids: Edward Doisy
Edward Doisy Harvard Medical School 1929
Extracts from sow ovaries (female pig) injected into ovarectomized mice (removed ovary), resulted in the production of cornified cells in the vagina – is a bioassay. Later isolated estradiol from pig follicular fluid.
When mice are about to ovulate, they enter into the oestrus cycle. They enter oestrus as they have a lot of estrogen, produced from the developing follicle. You can tell when a mouse has entered oestrus and it is ready to mate as there will be cornified cells around the vagina.
Doisy took the sow extract and injected into mice that had ovaries removed, he found that they stared to go into oestrus. So something in the sow extract resulted in the cornified cells in the mice.
Oestrogens & Sex Steroids ( Adolf Butenandt)
Adolf Butenandt University of Göttingen 1929
Isolated estrogen from hundreds of gallons of human pregnancy urine.
Pituitary & Gonadotrophins: Samuel Crowe
Samuel Crowe 1910
Partial pituitary ablation resulted in gonadal atrophy in dogs (no development of gonad/ testes) and persistence of infantilism in puppies.
If done to puppies they do not mature
Pituitary & Gonadotrophins: Bernard Aschner
Bernard Aschner 1912
Postulated that pituitary function determined by higher centres in the brain (hypothalamus) after observing gonadal atrophy in patients with brain injury.
Sectioned pituitary stalk which resulted in gonadal atrophy and hypothesised that brain/pituitary extracts might affect the gonads.
Identification of FSH & LH: Bernhard Zondek
Bernhard Zondek Berlin 1930
Proposed the idea that the pituitary secretes two hormones – Prolan A stimulated follicular growth (FSH) and prolan B stimulated ovulation and formation of the corpus luteum (LH).
He isolated these gonadotrophins from post menopausal blood and urine.
As after menopause there is no estrogen so with no estrogen, there is no negative feedback on the pituitary so the pituitary produces FSH and LH.
Also isolated hCG from pregnancy urine and injected into mice leading to follicular maturation and ovulation – potential pregnancy test.
Why does removal of hypothalamus/ pituitary result in tiny testes?
No FSH
FSH controls the development of Sertoli Cells
Friedman test- Bioassay of pregnancy
Maurice Friedman & Maxwell Lapham Pennsylvania 1931
Inject the tested woman’s urine into a female rabbit, then examined the rabbit’s ovaries a few days later… presence of corpus luteum indicated pregnancy.
Hormone responsible is hCG which binds to LH receptors causing luteinisation.
Drawback that the rabbit had to be operated on to examine ovaries.
Later development used the African clawed frog, which responds to hCG by laying eggs and so removing the need for surgery.
Human in- vitro fertilisation
John Rock & Miriam Menkin Harvard 1944
Culmination of 6 years of experiments changing conditions.
Oocytes obtained from patients around 10th day of the menstrual cycle by laparotomy.
Oocytes washed in Locke’s solution and incubated for 27 hours in serum obtained from the egg donor; exposure to a sperm suspension also washed in Locke’s solution for 1 hour. This resulted in an embryo
Transferred to a serum from a post-menopausal patient and observed over the following days where they divided into 2-4 cell embryos.
There was no attempt to transfer the embryos to a recipient.
BUT, use to create babies did not happen straight after
Fertility treatment 1950’s- 1970’s
1st use of hyperstimulation was in mice used crude extracts of Post menopausal serum (PMS) as it contains lots of LH and FSH, 1950’s
Hypogonadotrophic women treated with crude pituitary extracts & hCG (Gemzel, 1967).
Human menopausal gonadotrophins to treat amenorrhoeic women (Lunenfeld, 1969).
Anovulatory PCOS patients treated using clomiphene (Kistner, 1972). Blocks estrogen receptors.
Disadvantages of fertility treatment
(MULTIPLE PROBLEMS, ALSO NO ULTRASOUND MONITORING):
Multiple pregnancies
Ovarian Hyperstimulation syndrome (OHSS)
Miscarriage.
Purity of preparations. – danger of transmitting viruses.
CJD…other infectious agents.
Virtually no monitoring.
Ovarian Hyperstimulation syndrome (OHSS)
When a woman ovulates, there is continuous high estrogen from the developing follicle. This triggers the negative feedback to switch to positive, this causes the LH surge from the pituitary.
This LH spike acts on the ovary causing two main things to happen:
Causes resumption of meiosis 1
Triggers a series of inflammatory and tissue remodelling reactions that causes the release of the egg. One of the cytokines is vascular endothelial growth factor (VEGF), this causes increased vascular permeability this results in oedema and also more cytokines and cells to the site of inflammation.
But if you have given the woman a lot of FSH she could have 20 follicles ovulate. Then VEFG levels rise so high that they cause systemic vascular permeability. In the lungs this causes pulmonary oedema.
SO if you give FSH, you must monitor the number of follicles using ultrasound.
Laparotomy
surgical incision (cut) into the abdominal cavity
Laparoscopy
Patrick Steptoe - Graduated from St George’s in 1939.
Studied obstetrics and, in 1951 learned the technique of laparoscopy from one of its pioneers Raoul Palmer and promoted its usefulness.
One of the first people to use a laparoscope – can operate using just a couple of small holes.
Robert Edwards- Fertilisation
Began to study human fertilisation around 1960. Optimised culture media.
Discovered when to collect eggs after hCG trigger using ‘ovulations’ from pieces of ovary and oocyte maturation in vitro, 1965.
In-vitro matured fertilised eggs did not develop, problems with timing egg maturity and sperm capacitation, 1968.
Achieved fertilisation of a human egg in the laboratory 1969.
Next problem was obtaining follicular oocytes from selected patients. To solve this clinical problem, an inspired collaboration was initiated with Patrick Steptoe.
Steptoe & Edwards
Began working together
Measured urinary oestrogen in a gonadotrophin stimulated cycle.
Timed collection by laparoscopy IVF and replacement of embryos …..failure 1971.
Decided to give luteal support using Primulot which turned out to be an abortive agent. This wasted 3 years.
Switched to using a natural cycle and achieved 1st pregnancy but it was ectopic, 1977.
But was first successful in 1978 – Louise Brown
Clomiphene
Oestrogen receptor blocker
First line of treatment for PCOS
Progress in IVF technology
Purer urinary FSH/LH preparations, recombinant gonadotrophins
GnRH agonists/antagonists
Better ultrasound monitoring
Micromanipulation for ICSI, MESA, TESA etc
Cryopreservation of oocytes (vitrification)
Reduction in OHSS less stimulation & GnRH agonist/Kisspeptin triggers
Sequential media for blastocyst culture
Single embryo transfer
Pre-implantation diagnosis or screening
Ovarian tissue cryopreservation
Mitochondrial donation (3 parent family)
In vitro maturation of oocytes
OHSS
Too much FSH
VEGF causes systemic vascular permeability, may lead to pulmonary oedema
Preimplantation genetic testing (PGT)
Taking a cell from the embryo – embryo biopsy. Will then test these cells
PGT information used to decide which embryo to transfer to the mother.
PGT-A aneuploidy
PGT-SR chromosomal structural rearrangements
Screening of embryos for aneuploidy or chromosomal translocations. Often used for advanced maternal age risk of aneuploidy, know translocations or repeated implantation failure.
Eg increased risk of downsyndrome
PGT-M monogenic/single gene defects
Screening of embryos for known genetic mutations where the parents are carriers.
Screening of embryos includes fluorescence in situ-hybridisation (FISH), array-based comparative genomic hybridisation (aCGH), next-generation sequencing (NGS) and single nucleotide polymorphism (SNP) array. Also, whole genome amplification (WGA) based versions of techniques for PGT-M.
BUT you can only use it to test for genetic diseases
Background of origin of mitochondria
All mitochondria comes from the mother, there are some genetic diseases of the mitochondrial genes, so it will be passed onto a mothers children.
You can get a donor to donate their mitochondria
So offspring will have mothers and fathers nuclear DNA, but a different mitochondrial DNA.
