History and Development of ART Flashcards
When were sperm discovered?
- Anton Van Leeuwenoek 1677 (first microbiologist)
- First to observe and describe single-celled organism (animalcules)…microorganisms, muscle fibres, bacteria, capillaries and spermatozoa.
What was Hunter’s role in artificial insemination?
- Responsible for the first case of intrauterine insemination (Artificial insemination)
- 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.
- Hypospadias = opening of the urethra develops abnormally, usually on the underside of the penis. May be subcoronal, midshaft, penoscrotal etc. Abnormal closure of the urethral fold over the genital groove.
What was the first advancement in embryo transfer?
- 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.
How was it found that oestrogen from the ovaries had a sexual effect on the menstrual cycle?
1) Edward Doisy Harvard Medical School 1929
- Extracts from sow ovaries injected into ovarectomized mice, resulted in the production of cornified cells in the vagina – a bioassay. - Later isolated estradiol from pig follicular fluid.
2) Adolf Butenandt University of Göttingen 1929
- Isolated estrogen from hundreds of gallons of human pregnancy urine.
What is the structure of oestrogen?
- Similar to cholesterol = three 6-sided rings and a 5-sided ring.
- Side chain has been clipped off, so there are only 18 carbon atoms.
- Oestrone has one hydroxyl group, oestradiol has two and oestriol has three.
- E2 is the one found mainly in the menstrual cycle.
How was the HPG axis discovered?
1) Samuel Crowe 1910
Partial pituitary ablation resulted in gonadal atrophy in dogs and persistence of infantilism in puppies.
2) 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.
How were LH and FSH identified?
1) 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).
2) He isolated these gonadotrophins from post menopausal blood and urine.
What was the first bioassay of pregnancy (pregnancy test)?
1) 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.
When was Human in-vitro fertilisation
first carried out?
1) 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.
- Transferred to a serum from a post-menopausal patient and observed over the following days where they divided into 2-4 cell embryos. No attempt to transfer the embryos to a recipient.
What fertility treatments were created before the 70s?
1) 1st use of hyperstimulation was in mice used crude extracts of PMS, 1950’s
2) Hypogonadotrophic women treated with crude pituitary extracts & hCG (Gemzel, 1967).
3) Human menopausal gonadotrophins to treat amenorrhoeic women
(Lunenfeld, 1969).
4) Anovulatory PCOS patients treated using clomiphene (Kistner, 1972).
- Problems including Multiple pregnancies,
Ovarian Hyperstimulation syndrome (OHSS) = high VEGF from increased ovulation causes systemic vascular permeability (especially in lungs), Miscarriage, Purity of preparations.
CJD…other infectious agents, Virtually no monitoring.
When did laparoscopy become more popular?
1) Patrick Steptoe - Laparoscopy
- 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.
- In 1967 he published a book on Laparoscopy in Gynaecology.
How was laparoscopy used to improve IVF?
1) 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.
2) Steptoe & Edwards
- 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.
How has IVF technology progressed?
- 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 (culture embryos longer now)
- Single embryo transfer
- Pre-implantation diagnosis or screening
- Ovarian tissue cryopreservation
- Mitochondrial donation (3 parent family)
- In vitro maturation of oocytes
What is preimplantation genetic testing (PGT)?
- 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.
- 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.
- PGT information used to decide which embryo to transfer to the mother in IVF
- Embryo biopsy; taking cell(s) from the embryo to test.
What is mitochondrial donation?
- Three-parent family (cures mitochondrial diseases)
- All mitochondria comes from maternal oocyte. Mitochondria has its own set of genes that are involved in metabolic processes. There are some genetic diseases of those genes. These will be passed on and some are very serious.
- Donors can be used to donate their mitochondria. The child will have their parents’ nuclear DNA, but a donor’s mitochondria.
- Two ways of carrying it out =
1) Meiotic spindle transfer (MST) = Meiotic spindle of donor oocyte removed during MII and replaced by patient spindle. The two oocytes used have completed meiosis I and ready to ovulate. This egg is then fertilised.
2) Pronuclear transfer (PNT) = less common. Pronuclei of fertilised patient egg transferred to fertilised donor egg which has had pronuclei removed.
