Egg maturation issues

Question 1

Disorder of oocyte maturation

Answer 1

Incidence of this syndrome currently unknown.
Number of case studies have demonstrated patients with repeated oocyte maturation failure
- primary infertility
- Repetitive production of mostly immature oocytes
- Inability for IVM to stimulate maturation
- Fertilisation failure despite ICSI

Question 2

Process of oocyte maturation

Answer 2

Highly complex
Needs to acquire meiotic competence
mRNA and proteins are acquired during growth to complete meiosis
Meiosis achieved by key regulation of protein production, phosphorylation and degrasadation
GV arrrest = possible failure in maturation promoting factor (MPF)
M1 arrest = often associated with chromosomal abberations such as anaphase promoting complex deficiency

Question 3

Features of GV, M1, M2 oocyte

Answer 3

Germinal vesicle (GV) - characterized by an intracytoplasmic nucleus (germinal vessel)
M1 (meiosis 1) - no GV and no PB
M2 (meosis 2) - polar body present

Question 4

Increased degeneration/fragile eggs

Answer 4

Vienna consensus = <10% oocyte degeneration “lyse”
Can happen immediately after injection or the next day
Limited information on the cause of degradation.
Linked to inherent quality of oocytes but also stimulation regime.

Question 5

Interventions for fragile eggs

Answer 5

Thin walled injection pipette - minimise amount of cytoplasmic aspiration, minimse amount of PVP injected (the solution used to slow sperm for easy ICSI manipulation)

Laser-mediated ICSI
- micro-hole lasered in the zona prior to injection
- potential benefit seen
- issues around finding the hole
- concern around monozygotic twinning

PIEZO ICSI

Question 6

Piezo ICSI

Answer 6

Blunt end micropipette
Operation fluid loaded into pipette
piezoelectric actuator is used to move the capillary in a rapid fashion by producing utlra-fast submicron motion which propels the capillary forward
Actuator is made of material that when a voltage is applied to chagnes shap and extrudes a force which moves the capillary in a forward micro-jack hammer like motion.
Found to decrease degeneration and increas fertilisation rates

Question 7

Poor embryo/blastocyst development

Answer 7

Can be caused by cytoplasmic deficiencies and mt dysfunction - much remains unknown
Treatment interventions are more novel
- specific culture media (+ anti-oxidants) - to try and mitigate oxidative stress
- biphasic O2 exposure
- fragmentation removal
- spindle transfer

Question 8

Summary:
Oocytes struggling to mautre
Failed/low fert
Increased lysis and fragile eggs
Poor blast formation/high aneuploidy rates

Answer 8

Oocytes struggling to mature: Altered stim regime, donor eggs
Failed/low fert: “aggressive ICSI”, AOA, Vitrolife (antioxidant containing medium Gx series), PIEZO-ICSI
Increased lysis and fragile eggs - modified injection needles, laser assisted ICSI, PIEZO-ICSI
Poor blast formation/high aneuploidy rates - antioxidant containing media (Vitrolife),