Lecture Notes on Oocytes and Assisted Reproduction

Traditional View on Oocytes:

• Dogma: Females are born with all the oocytes they will ever have.
• Belief: Mitotic proliferation of oocytes is restricted to fetal life.
• Post-birth: No mitosis of orgonia (stem cells, gamete precursors).

Challenging the Dogma:

• New Research: Published nearly 10 years ago in Nature Medicine.
• Findings: Suggested presence of ogonial stem cells in adult ovaries.

Research Methods and Findings:

• Sample Collection: Biopsies from healthy young women.
• Isolation of Cells: Using DDX4 specific antibody.
  • DDX4: Dead Box Polypeptide 4, an RNA helicase specific to germ cells.
  • Results: Isolated mitotically active germ cells.
• Fluorescent Labelling: Labeled cells with GFP.
• Reintroduction to Biopsies: Cells introduced back into human ovary biopsies.
  • Observation: GFP positive cells formed aggregates resembling follicles.
• Mouse Model Experiment:
  • Use of Skid Mice: To prevent immune reaction.
  • Findings: GFP positive follicles indicate human origin.
  • Interpretation: Mitosis of germ cells possible in adult ovaries.

Implications for Assisted Reproduction:

• Potential: New areas for assisted reproduction technologies.
• Current Limitations: Translation of mouse model work to humans is pending.

Recent Advances with Stem Cells:

• Mouse Model Research:
  • Approach: Use of pluripotent stem cells (embryonic/induced).
  • Differentiation: Into primordial germ cell-like cells.
  • In Vitro Ovary Reconstitution: Mixing with somatic cells from mouse ovaries.
  • Development: Follicles developed, matured, and fertilized.
  • Outcome: Live births with healthy offspring.

Potential Human Application:

• Current Practice: Assisted reproduction extracts mature oocytes.
• Future Possibilities:
  • Pre-stage Development: Ability to create viable oocytes from stem cells.
  • Challenges: Technical and ethical challenges in translating to humans.
  • Benefits: Bypass issues in assisted reproduction, like oocyte quality and quantity.

Conclusion:

• Future Prospects: Research could open new avenues for infertility treatment.
• Ongoing Challenges: Need to address technical, ethical issues.