Organ Donation, Transplants, and Stem Cell Therapies

Posted on Jan 11, 2025 in Biology

Who Can Be a Donor?

A donor is typically a person in a state of brain death, where brain function has ceased, but the heartbeat is artificially maintained to keep organs viable for transplantation. In some cases, a living person can be a donor, particularly for tissues or renewable organs.

Spanish Legislation Regarding Organ Donation:

  • Establishment of brain death by medical professionals.
  • Respect for the deceased’s wishes regarding organ donation.
  • Diagnosis of death must be made by physicians.
  • Donation is altruistic.
  • Guarantee of donor anonymity.
  • Application of medical criteria for organ distribution.

Transplant Types

  • Autograft: Donor and recipient are the same individual, eliminating rejection.
  • Isotransplant: Donor and recipient are identical twins, also eliminating rejection.
  • Xenotransplantation: Donor and recipient are of different species, carrying a risk of rejection.
  • Allogeneic: Donor and recipient are of the same species but not genetically identical, with a risk of rejection.

Bone marrow, found inside bones, produces all types of blood cells. Transplantation can treat serious diseases.

The spinal cord consists of nerve tissue within the spine.

Embryonic Development

Embryo implantation in the endometrium has low efficiency due to the high cost of pregnancy. Evolution has developed mechanisms to ensure only the best survive.

The nervous system begins to form. The embryo continues to grow and develop.

Organs begin to function. By two months, the embryonic period transitions to the fetal period, characterized by the growth of these structures.

Assisted Reproduction

  • Artificial Insemination: Sperm is inserted into the female reproductive tract.
  • In Vitro Fertilization and Embryo Transfer (IVF-ET): Fertilization of an egg with sperm in a laboratory.

IVF-ET Steps:

  1. Obtaining eggs
  2. Fertilization
  3. Embryo transfer

Types of Stem Cells

  • Totipotent: Cells capable of generating a complete individual. Blastocysts are totipotent.
  • Pluripotent: Cells that can generate all cell types but retain the ability to differentiate into any cell type.
  • Multipotent: Adult cells that retain the ability to differentiate into some, but not all, cell types.

Regenerative Medicine

Embryonic stem cells from early embryos are most promising due to their pluripotency.

Adult stem cells are present in all human tissues but in varying amounts.

Induced pluripotent cells are under investigation and offer hope. Specialized adult cells are treated to dedifferentiate and transform back into pluripotent embryonic stem cells.

Nuclear Transfer

  1. A differentiated cell is obtained from the individual to be cloned.
  2. An egg is extracted from a female donor.
  3. The egg nucleus is removed.
  4. The differentiated cell nucleus is transferred to the enucleated egg.
  5. The cell is grown in the laboratory.
  6. It is transferred to the uterus at the morula stage.
  7. After gestation, a new individual is born, a clone of the nucleus donor.