Transplantation

Transplantation and its use in gene technology by Christopher Schlemm and Ilja Klebanov

Introduction General information Methods of transplantation: 3.1 Autografting 3.2 Allografting 3.3 Xenografting Problems of transplantation Gene technology as a solution 5.1 Organ breeding 5.2 Suppression of rejection 5.3 Ideas for the future Conclusion Structure

General information Definition: to transfer a graft (an organ or tissue) from one part or individual to another • May take place between: • different parts of the same organism (autografting) • different organisms of the same species (allografting) • different species (xenografting)

General information: 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

Methods of Transplantation: 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: Allografting • 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.

Allografting: Applications of allografting transplantation

Allografting: The importance of transplantation:

Methods of Transplantation: 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

Xenotransplantation: From which animals are we able to transplant organs 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 solution What is possible using gene technology refering to the problems? • Gene technology offers the possibility to breed the desired organs in animals. Lack of organs is no longer a problem • 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 as a solution: 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 microinjection The DNA is inserted into the cell with a small syringe II. Retrovirus gene transfer The 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 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 rejected pancreas It is possible to humanize the bred organs by making certain genetic modifications. Then the organs are accepted by the immune system.

Gene technology as a solution: Ideas for the future • Organ 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

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

Transplantation