Main   Terms   People   Interviews   Resources   Events

Xenotransplantation and its Associated Safety and Ethical Issues

Mary E. White-Scharf. Vice President of Research, Biotransplant, Inc.

Glossary: endogenous

Xenotransplantation, Safety and Ethical Issues

  • Xenotransplantation: Transplantation of tissue from one species to another
  • Allotransplantation: Transplantation of tissue from one individual to another within a given species

Types of Xenotransplantation

  • Cell Transplants
    Fetal neural
  • Ex vivo Organ Assist
  • Solid Organ Transplants

Non-human Primates as Donors

Breeding Issues

  • Long gestation period
  • Single births
  • Lack of controlled environment

Ethical Issues

  • Non-human primates are genetically more closely related to humans

Potential Health Risks

Regulatory Update

  • FDA Issued Guidelines for Comments in April 1999: Guidance for Industry – Public Health Issues Posed by the Use of Non-human Primate Xenografts in Humans”

    Non-human primate donors for xenotransplantation cannot be proposed for clinical use until scientific research and evaluation can identify risks associated with such transplant protocols.

Pigs as Organ Donors

Breeding Issues

  • Short gestation period
  • Born in litters
  • Barrier facilities established

Ethical Issues

  • Over 93 million pigs per year in the US are slaughtered for food

Potential Health Risks

  • Exogenous viruses: eliminated by raising in barrier facilities
  • Endogenous retroviruses: no pathogens identified

Advantage of Inbred Miniature Swine

  • MHC Inbred and Recombinant Lines are Available
  • Twenty-five Years of Breeding and Medical History
  • Physiology Similar to that of Humans
  • Transplantation Technology Available Including Species Specific Cytokines and Antibody Reagents
  • Model Consistent with Clinical Findings

Scientific Issues Associated with Xenotransplantation

Two Major Hurdles

  • Humans have naturally occurring antibodies which react with carbohydrates on the surface of pig cells
  • The human immune response to xenogeneic tissue is very strong and difficult to manage

Major Scientific Approaches to Achieving Xenotransplantation

  • Develop Specific Immune Tolerance
  • Genetically Engineer Pigs

Ethical Issues Associated with Xenotransplantation

Potential Health Risks

  • Risks to the Patient
  • Risks to Society

Risks to the Patient

  • Allotransplants
    HIV, Hepatitis, CMV
  • Xenotransplants
    PERVs, unknown viruses

Risks to Society

  • Potential for Recombination Among Pig and Human Retroviruses to Form Pathogenic, Infectious Strains
  • Potential for Emergence of Unknown Zoonosis

What Can Be Done to Manage Risks?

  • Identify and Characterize PERVs
  • Develop Assays to Monitor Infection
  • Acquire and Test Samples
    From individuals with long-term exposure to pigs or pig products, such as pig farmers
    From burn patients who had pig skin transplants
  • Perform Carefully Controlled and Well Monitored Clinical Studies in a Limited Number of Individuals

Email link | Feedback | Contributed by: Boston University. Video adapted from the Issues for the Millennium Workshop

Topic Sets Available

AAAS Report on Stem-Cells

AstroTheology: Religious Reflections on Extraterrestrial Life Forms

Agency: Human, Robotic and Divine
Becoming Human: Brain, Mind, Emergence
Big Bang Cosmology and Theology (GHC)
Cosmic Questions Interviews

Cosmos and Creator
Creativity, Spirituality and Computing Technologies
CTNS Content Home
Darwin: A Friend to Religion?
Demystifying Information Technology
Divine Action (GHC)
Dreams and Dreaming: Neuroscientific and Religious Visions'
E. Coli at the No Free Lunchroom
Engaging Extra-Terrestrial Intelligence: An Adventure in Astro-Ethics
Evangelical Atheism: a response to Richard Dawkins
Ecology and Christian Theology
Evolution: What Should We Teach Our Children in Our Schools?
Evolution and Providence
Evolution and Creation Survey
Evolution and Theology (GHC)
Evolution, Creation, and Semiotics

The Expelled Controversy
Faith and Reason: An Introduction
Faith in the Future: Religion, Aging, and Healthcare in the 21st Century

Francisco Ayala on Evolution

From Christian Passions to Scientific Emotions
Genetic Engineering and Food

Genetics and Ethics
Genetic Technologies - the Radical Revision of Human Existence and the Natural World

Genomics, Nanotechnology and Robotics
Getting Mind out of Meat
God and Creation: Jewish, Christian, and Muslim Perspectives on Big Bang Cosmology
God, Humanity and the Cosmos: A Textbook in Science and Religion
God the Spirit - and Natural Science
Historical Examples of the Science and Religion Debate (GHC)
History of Creationism
Intelligent Design Coming Clean

Issues for the Millennium: Cloning and Genetic Technologies
Jean Vanier of L'Arche
Nano-Technology and Nano-ethics
Natural Science and Christian Theology - A Select Bibliography
Neuroscience and the Soul
Outlines of the Science and Religion Debate (GHC)

Perspectives on Evolution

Physics and Theology
Quantum Mechanics and Theology (GHC)
Questions that Shape Our Future
Reductionism (GHC)
Reintroducing Teleology Into Science
Science and Suffering

Scientific Perspectives on Divine Action (CTNS/Vatican Series)

Space Exploration and Positive Stewardship

Stem-Cell Debate: Ethical Questions
Stem-Cell Ethics: A Theological Brief

Stem-Cell Questions
Theistic Evolution: A Christian Alternative to Atheism, Creationism, and Intelligent Design...
Theology and Science: Current Issues and Future Directions
Unscientific America: How science illiteracy threatens our future
Will ET End Religion?

Current Stats: topics: >2600, links: >300,000, video: 200 hours.