Organ and Tissue Donation: Medical and Ethical Considerations

Posted on Dec 7, 2024 in Biology

Organ and Tissue Transplantation

Transplanting involves the replacement of a diseased organ or tissue that endangers a person’s life. This is done so that the receptors, on the other hand, can function properly. A donor is usually a person who is encephalic-dead or brain-dead (their brain stops working, but their heartbeats are kept artificially). A donor can also be a living person.

Spanish Legislation on Organ Donation

  1. Definition of brain death as a scientific, legal, and ethical concept of the individual.
  2. Respect for the will of the deceased as to whether or not to donate.
  3. Death diagnosis is made by a team of doctors independent of the transplant team.
  4. Altruistic character and non-commercialization.
  5. Guarantee of donor anonymity.
  6. Application of medical criteria for distribution.

Types of Transplants

  • Autotransplantation or autograft: The donor and recipient are the same. No rejection occurs.
  • Isotransplant: The donor and recipient are identical twins. No rejection occurs.
  • Xenotransplantation: The donor and recipient are of different species. There is a risk of rejection.
  • Allogeneic transplantation: The donor and recipient are individuals of the same species but are not genetically identical. There is a risk of rejection.

Challenges in Transplantation

  1. Immune rejection: Donor and recipient must be compatible. Immunosuppressants are used to prevent organ rejection.
  2. Shortage of available organs.
  3. Technical impossibility of obtaining certain organs and tissues.

Spinal Cord: Nerve tissue lining the vertebral column. It cannot be replaced.

Organs and Tissues That Can Be Donated

Lungs, heart, kidney, liver, pancreas, skin, cornea, bone, heart valves, blood vessels, pancreatic cells, and bone marrow (the substance inside the bones that produces all blood cells; its transplant allows the cure of serious diseases), umbilical cord blood.

Human Development and Assisted Reproduction

Fertilization: The union of an egg and sperm, which occurs within the fallopian tube. This forms the zygote.

Development: The first part of development ends at birth and is called embryonic development. Postnatal development begins at birth.

Early Stages of Embryonic Development

  1. The sperm is inserted into an egg in a fallopian tube, forming a zygote.
  2. The zygote continues to move down the tube on its way to the uterus and begins to divide.
  3. The cells continue to divide to form an embryo of 32 cells (morula).
  4. A cavity forms inside the morula, which takes the form of a hollow ball (early blastocyst).
  5. A group of cells condenses inside the blastocyst and forms a compact mass (late blastocyst).
  6. The embryo nests on the wall of the uterus, covered with a layer called the endometrium.

Key Points of Development

  1. Implantation of the embryo in the endometrium.
  2. Initiation of the nervous system by 14 days.
  3. Organs begin to function at about 2 months (fetus).

Assisted reproduction: Techniques to overcome the impossibility or difficulty of people to have children.

  1. Artificial insemination: Sperm are artificially introduced into the female genital tract.
  2. In vitro fertilization and embryo transfer (IVF-ET): Fertilization of the egg with a sperm outside the woman’s body in a laboratory.

Stages of IVF-ET

  1. Obtaining eggs: Hormone treatment stimulates the production of eggs in the woman’s ovaries.
  2. Fertilization: Eggs are fertilized by previously obtained sperm in a laboratory test tube.
  3. Embryo transfer: The embryo is transferred into the woman’s uterus.

Stem Cells and Regenerative Medicine

Stem cells: Undifferentiated cells capable of multiplying for long periods, giving rise to more undifferentiated cells, and differentiating into specialized cells.

Types of Stem Cells

  1. Totipotent (zygote and blastomeres): Can give rise to a complete individual.
  2. Pluripotent: Cannot give rise to a complete individual but can give rise to all cell types.
  3. Multipotent: Have the capacity to originate not all, but some, cell types.
  4. Oligopotent: Can only give rise to one or a few cell types.

Regenerative medicine: A biomedical field that produces tissues or functional organs to replace those affected. The following stem cells can be used:

  1. Embryonic: From early embryos.
  2. Adult (tissue): Found in all human tissues.
  3. Induced pluripotent stem cells (iPSCs): Specialized adult cells are treated to differentiate and transform back into pluripotent embryonic stem cells.

Cloning and Bioethics

Cloning: The process by which an exact copy or clone is obtained from the genetic standpoint of any living entity.

Nuclear Transfer

A technique used to clone animals.

Stages of Nuclear Transfer

  1. A differentiated cell is obtained from the individual to be cloned.
  2. An egg is obtained from a female.
  3. The nucleus of the egg is extracted.
  4. The nucleus of the differentiated cell is transferred to the egg.
  5. The egg is cultivated to allow the embryo to begin to develop.
  6. When the embryo is in the morula stage, it is transferred to the uterus of a surrogate mother.
  7. After the gestation period, a new individual is born.

Bioethics: The branch of ethics that attempts to provide guiding principles for human behavior in the biomedical field.