Transplantationand its use in gene technology

by Christopher Schlemm and Ilja Klebanov

Structure

1. Introduction

2. General information

3. Methods of transplantation:3.1 Autografting

3.2 Allografting

3.3 Xenografting

4. Problems of transplantation

5. Gene technology as a solution5.1 Organ breeding5.2 Suppression of

rejection5.3 Ideas for the future

6. Conclusion

General information

May take place between: different parts of the same organism (autografting) different organisms of the same species (allografting) different species

(xenografting)

Definition: to transfer a graft (an organ or tissue) from one part or individual to another

Immune system rejection

Often a transplanted organ is not identified by the immune system as the tissue of the organism

It can be attacked and destroyed.

Against this effect the patient has to swallow Immunesuppressiva which cause symptoms like suffering from AIDS.

In 15-20 minutes the organ dies, unable to withstand the immune system attack. Rejection

of a heart

General information:

Autografting

• The transfer of self tissue from one body site to another in the same individual

• Due to the genetic homology of the tissue, the immune system does not respond to it

• Use: synthetic implantation skin grafts bone marrow transplantation hair

Methods of Transplantation:

AllograftingMethods of Transplantation:

Definition: The transfer of organs or tissue from human to

human or from cadaver to human

• As there are more and more people every year waiting for donor organs and tissues, allografting transplantation has become quite common.

• Allografting transplantation has many applications.

Applications of allografting transplantationAllografting:

The importance of transplantation:Allografting:

Xenografting

Definition: Xenotransplantation – the transfer of tissue from one species to another

Usually refers to the implantation of animal tissue in humans provides a new source of organs for

humans many different types of tissue can be

transplanted:e.g. heart, kidney, liver or lung

Methods of Transplantation:

From which animals are we able to transplant organs

Xenotransplantation:

1. The Chimpanzee:Its DNA sequence differs from ours by only 2%

2. The Baboon:Its organs are too small for a large adult human

3. The Pig:Surprisingly similar too our anatomy and physiology

Problems of Transplantation• There are not enough organs

At least 150,000 patients in industrially developed countries badly need donor organs and tissues

Every 14 minutes another name is added to the national transplant waiting list.

About 16 people die because of the lack of available organs for transplant each day.

• Rejection:When the immune system of the host detects

foreign graft tissue, it launches an attack, resulting in tissue rejection

Gene technology as a solutionWhat is possible using gene technology refering to the problems?

Gene technology makes it possible to humanize the bred organs - the immune system identifies the organ as its own tissue.

Immune system rejection is prevented

Gene technology offers the possibility to breed the desired organs in animals.

Lack of organs is no longer a problem

Gene technology - transgenic animals

Organ breeding:•A transgenic animal carries a foreign gene that has been inserted into its genome.

•The transgenic animal shows the specific characteristics which are coded on the inserted gene

A gene which is responsible for the construction of a human organ makes the organism produce the organ additionally.

Gene technology as a solution:

The insert of a foreign gene into an animal

I. DNA microinjectionThe DNA is inserted into the cell with a small syringe

II. Retrovirus gene transferThe DNA is carried into a cell by a virus.The virus carries the desired DNA and infects the cell, which has the effect that the DNA is built into the cell‘s DNA.

Gene technology as a solution:

Suppression of immune system rejection

It is possible to humanize the bred organs by making certain genetic modifications.Then the organs are accepted by the immune system.

The immune system has the task to protect the organism against every foreign cell.

The immune system distinguishes between cells of the body and foreign cells.

The genes which are responsible for the own tissue not being rejected can be injected into an animal embryo the organs of which are then similar to the ones of the human.

Not rejectedpancreas

Gene technology as a solution:

Ideas for the futureOrgan breeding by using stem cells:

•Stem cells are able to become any cell which is found in the human. Under specific conditions stem cells could become cells of a kidney, a brain and so on.

•Thus by using one stem cell from an embryo a whole new organ could be created.

Embryo Stem cell Cell differentiation

Gene technology as a solution:

Conclusion

• During the era of gene technology transplantation has improved very much

• In future donors won‘t be needed any longer• Scientists will be able to breed organs and to adapt

them to the organism of the patient• Most of the ethnical problems will be eliminated