Stem Cells & Reproductive Technologies Extended Response

Question 1

Explain In-vitro fertilisation (IVF) and identify in which situations it would be useful.

Answer 1

• IN VITRO FERTILISATION (IVF) is used where a couple are unable to produce viable ova or sperm, or both.
• IVF uses a mans sperm to fertilise a woman’s ovum outside the body (in vitro = in a laboratory vessel).
• After fertilisation the dividing cells are transferred to the mother’s uterus.

Question 2

Explain Gamete intrafallopian transfer (GIFT) and identify in which situations it would be useful.

Answer 2

• A variation of IVF where eggs and sperm are mixed together immediately after eggs have been collected.
• The mixture is then injected into the women’s fallopian tubes which allows egg and sperm to mix naturally in the hope of fertilisation.
• A fertilised egg will then travel down the uterine tube and implant as usual.
• Situations it would be useful:
• Couples with unexplained infertility
  -IVF without success
  -Both spouses have religious or ethical factors and cannot accept IVF
• Only at least one side of the fallopian tube is healthy
• Husband’s sperm quantity and quality.

Question 3

Explain Zygote intrafallopian transfer and identify in which situations it would be useful?

Answer 3

• Another variation where eggs are fertilised in a dish in a lab and then transferred to the women’s fallopian tubes at the one-cell or zygote stage of development (the day after fertilisation).
• Requires 2 operations 24hrs apart, one to collect eggs and one to place zygote in fallopian tube

Question 4

Explain Intracytoplasmic sperm injection (ICSI) and identify in which situations it would be useful?

Answer 4

• If a mans sperm count is very low or there is low mobility of sperm then ICSI may be used.
• A single sperm is injected into a single egg and the resulting embryo is transplanted into the
  women’s uterus.

Question 5

Explain artificial insemination by donor (AID) and identify in which situations it would be useful?

Answer 5

• When a man is sterile and unable to produce sperm, a couple may choose to have semen donated by a donor.
• The characteristics of males are matched.
• Around the time ovulation is expected the donors sperm is injected into the upper vagina for 3 or 4 successive days
• 70-80% of couples achieve success.
• Possible transmission of diseases

Question 6

What are stem cells?

Answer 6

Stem cells are undifferentiated cells that can become multiple cell types as well as undergoing repeated mitotic divisions (self-renewal)

Question 7

What is a stem cell line?

Answer 7

A stem cell line is a group of identical stem cells that can be grown and nurtured in a lab dish. Stem cell lines are valuable resources for research, as they allow scientists to study and investigate the properties and behaviors of stem cells in a controlled environment.

Question 8

Differences between embryonic stem cells and adult stem cells

Answer 8

Embryonic stem cells are derived from early-stage embryos and are pluripotent, allowing them to differentiate into any cell type. Adult stem cells, on the other hand, are found in various tissues and are multipotent, with a more limited differentiation capacity.

Question 9

Three types of stem cells and differences (in terms of potency)

Answer 9

• Multipotent – most limited, sometimes called adult stem cells can give rise to different cell types within a cell lineage e.g. blood stem cells can give rise to platelets, RBCs, or WBCs but not a bone cell
• Pluripotent – can be come all cell lineages, but not the cells that form the outer layer of the blastocyst
• Totipotent – can become ANY cell, only applies to cells present after first few rounds of division after fertilisation

Question 10

What is cell replacement therapy?

Answer 10

Cell therapy refers to placing new, healthy cells into the body to replace diseased or damaged ones.

The idea behind cell replacement therapy is to restore the normal structure and function of damaged tissues or organs by introducing new, functional cells.

The therapy involves the use of stem cells or specialized cells that have been grown or generated in the laboratory. These cells are carefully selected based on their ability to differentiate into the specific cell types needed for the replacement.

Question 11

What is tissue engineering?

Answer 11

Tissue engineering is an interdisciplinary field that combines principles from engineering, biology, and medicine to create artificial tissues and organs for transplantation or research purposes. The goal of tissue engineering is to develop functional and viable substitutes that can repair or replace damaged or diseased tissues in the human body.

Tissue enginerring has been found useful for the following:
- For treating burn injuries and chronic wounds.
- For repairing bone defects or fractures.
- For treating cartilage damage in joints.

Question 12

Explain the process of differentiation

Answer 12

Differentiation is the process by which cells become specialised. When cells undergo division by mitosis, different genes become activated. This causes the cells to differentiate into specialised cells that can perform particular functions - for example stomach cells that secret enzymes, or muscle cells that can contract

Question 13

What is therapeutic stem cell cloning

Answer 13

Therapeutic stem cell cloning is a laboratory technique used to create embryonic stem cells that are genetically identical to a patient. The goal of this technique is to generate patient-specific stem cells, which can then be used for various therapeutic purposes, such as regenerative medicine and disease treatment.
Steps are:
1. Donor cell collection
2. Nuclear Transfer: The nucleus of the donor cell, which contains the patient’s genetic material (DNA), is transferred into an unfertilized egg cell that has had its nucleus removed.
3. Cell Fusion: The egg cell with the patient’s DNA and the donor nucleus are fused together
4. Embryonic Stem Cell Extraction: Pluripotent stem cells extracted, embryo itself not used
5. Stem Cell Culture: The extracted embryonic stem cells are then cultured and encouraged to multiply in the laboratory.
6. Differentiation: The laboratory-cultured stem cells are then induced to differentiate into the specific cell type needed for the therapeutic treatment.

Question 14

Ways in which stem cells are utilised in therapies today:

Answer 14

• Bone Marrow Transplant
• Treatment of Autoimmune Diseases
• Corneal Repair
• Burn Treatment
• Treatment of Genetic Disorders

Question 15

Ways in which stem cells might be used in future therapies:

Answer 15

Organ Regeneration and Replacement

Treating Neurological Diseases and Injuries

Diabetes Treatment

Treat Musculoskeletal Disorders

Vision Restoration

Treat More Autoimmune Diseases

Cancer Treatment

Drug Testing and Disease Modeling

Gene Editing Therapies

Question 16

What is cord blood and why is it a valuable resource?

Answer 16

Cord blood is the blood collected from the umbilical cord and placenta after a baby is born. Here are some reasons why cord blood is considered valuable:

Rich Source of Stem Cells: Cord blood is a rich source of hematopoietic stem cells (HSCs) These HSCs have the ability to differentiate into various types of blood cells, such as red blood cells, white blood cells, and platelets. HSCs are crucial for the regeneration of the blood and immune systems and are used in the treatment of various blood-related disorders, including leukemia, lymphoma, and anemia.

Non-Invasive and Painless to Collect

Higher Recipient Match Likelihood

Low Risk of Transmissible Infections

Versatility in Research: Cord blood stem cells are valuable for scientific research, including studies on stem cell biology, regenerative medicine, and the development of potential new therapies.

Future Potential: As research in stem cell biology and regenerative medicine progresses, cord blood may become even more valuable, with the potential for new and advanced treatments for various diseases and conditions.

Question 17

What is regenerative medicine

Answer 17

Regenerative medicine is an interdisciplinary field that aims to restore or replace damaged, diseased, or injured tissues and organs in the body. The goal of regenerative medicine is to promote the body’s natural healing processes or to use advanced therapeutic techniques to stimulate tissue repair, regeneration, and functional restoration.
Examples of regenerative medicine include:
- Stem cell therapies
Stem cell therapies involve the transplantation or manipulation of stem cells to promote tissue repair and regeneration.
- Tissue engineering
- Gene therapies

Question 18

What are some of the ethical concerns associated with stem cell research and use?

Answer 18

Some of the key ethical concerns associated with stem cell research and use are:

• Embryonic Stem Cell (ESC) Research: One of the most significant ethical controversies in stem cell research is the use of embryonic stem cells, which are derived from early-stage embryos. The process of obtaining ESCs typically involves the destruction of the embryo, leading to debates over the moral status of the embryo and the right to life.

Embryonic stem cell research poses a moral dilemma. It forces us to choose between two moral principles:

No consent

The duty to prevent or alleviate suffering
The duty to respect the value of human life
In the case of embryonic stem cell research, it is impossible to respect both moral principles.To obtain embryonic stem cells, the early embryo has to be destroyed. This means destroying a potential human life. But embryonic stem cell research could lead to the discovery of new medical treatments that would alleviate the suffering of many people. So which moral principle should have the upper hand in this situation?