~~ BERTSCHINGER--~~------------------------------~~\

praklinischen Entwicklungsphase Trans-plantationsversuche von einer Tierart aufeine andere befriedigende Ergebnisse ge-zeigt haben. Bei diesen Versuchen konnen- neben der Belastung durch den chirurgi-schen Eingriff der Transplantation - alsFolge der Reaktionen auf das fremde Ge-we be massive Gesundheitsstorungen ent-stehen, sodass die Empfangertiere sterbenoder eingeschlafert werden miissen. Diesgilt zumindest, bis die Technik zu grosse-rer Reife gebracht worden ist.

Bei konsequenter Durchsetzung einesabsoluten Respektes fur alles Leben wiirdesich die Nutzung von Tieren als Organs pen-der verbieten. Allerdings mtisste dann derUmgang mit Tieren in unserer Kultur inje-der Beziehung neu tiberdacht werden, nichtnur in Bezug auf die Nutzung in Tierversu-chen und fur die Xenotransplantation.

Eingriffe in das Wohl und das Leben vonTieren diirfen - urn die Wiirde der Tierezu wahren - nicht ohne iiberzeugendeGriinde vorgenommen werden. 1m heuti-gen Augenblick kann die zukiinftige Be-deutung der Xenotransplantation nochnicht abgeschatzt werden. Noch sind dieRisiken der Ubertragung menschenpatho-gener Erreger nicht abschliessend beurteil-bar, und manche technischen Bereichemiissen weiter entwickelt werden. Es lasstsich daher auch nicht mit Sicherheit sa-gen, ob das angestrebte Ziel erreicht wer-den kann und die Tierversuche somit ih-ren Zweck erfiillen. Dieser Schwachpunkttrifft jedoch fur jede Art der Forschung zu.

Bei der Xenotransplantation tierischerOrgane stehen sich die Interessen vonMensch und Tier diametral gegeniiber undmiissen in jedem einzelnen Fall sorgfaltig

. gegeneinander abgewogen werden. In derPhase der Entwicklung dieses Verfahrensist eine generelle Beurteilung der Zulas-sigkeit des Einsatzes von Tieren nichtmoglich. Die folgenden Hauptaspektemiissen im Sinne einer Gtiterabwagungbesonders gewiirdigt werden:~ der im besten Fall mogliche Nutzen (Le-bensqualitat, Uberlebensdauer) fur denOrganernpfanger~ die versuchsbedingte Belastung derEmpfangertiere in der praklinischen Pha-se~ die Einfuhrung einer Vielzahl mensch-licher Gene ins Erbgut der Tiere und mog-liche Folgen fur deren Wohlbefinden~ die Lebensbedingungen der Spender-tiere unter dem fur die Transplantation ge-forderten Gesundheitsstatus~ der Tod vieler Tiere an sich.

Contribution to the ethical appraisal ofxenotransplantation with respect to protectionof the dignity of the animalsHans U. BertschingerEthical Comittee for Experiments in Animals of the Swiss Academy of Medical Sciences and the Swiss Academy of Natural Sci-ences

The spectacular advances that havebeen made in the field of human organtransplantation have improved not onlythe life expectancy, but also the qualityof life for a large number of patients.However, the increasing demand fordonor organs can no longer be met.Xenotransplantation is one of manypossibilities for closing the gap betweenthe growing demand for organs and thelimited supply from donors. Xenotrans-plantation is understood to mean theremoval of live organs, tissues or cellsfrom animals and their transplantationin human patients. From the animal-eth-ics point of view, appraisal of the trans-plantation of whole organs is of primeimportance. The fundamental question,whether the implantation of animal or-

gans in humans is acceptable, has to beanswered by society as a whole. TheSwiss Academy of Medical Scienceshas undertaken the task of drawing upguidelines on xenotransplantation forthe physicians and surgeons involved inthis field. The aim of this present state-ment is to address a further aspect,namely the ethical appraisal ofxenotransplantation with respect to pro-tection of the dignity of the animals.

The use of animals for the benefit andthe good of humans has been practisedfor time immemorial, and since the be-ginning of philosophical and religioustradition it has again and again been putinto question. In Europe, the use of an-imals for biomedical research in partic-ular is accepted by the majority of the

1 Ethical Principles and Guidelines for Scientific Experiments on Animals (latest version 1995).2 Statement to the term "dignity of the animal" (1997).(These publications can both be ordered at: Sekretariat SANW, Barenplatz 2, CH-3011 Bern.)

ALTEX 17, 1/00

population, but rejected by a minority.Both its proponents and its opponentsput forward sincere, convincing argu-ments. In the knowledge that on the onehand, Man cannot do without scientificexperiments in animals, while on theother the ethical principle of respect forlife calls on him to protect animals, theSwiss Academy of Medical Sciences(SAMS) and the Swiss Academy ofNatural Sciences (SANS) published eth-ical principles and guidelines (EPG) forscientific experiments in animals for thefirst time in 1983. These were revisedand extended in 19951. They provideaids to decision making in this contro-versial area. Further, the Ethical Com-mittee for Experiments in Animals ofthe SAMS and the SANS gave its opin-ion concerning the term "dignity of theanimal'". Even with different basic at-titudes, we all have the moral obliga-

23

_B_ER_T_S_CH_I_N_G_ER ~§~----cC

~c

tion to recognise the dignity of animals,to take proper account of the most im-portant interests of both humans andanimals and to come to decisions onlyafter giving responsible and careful con-sideration to all the circumstances.The use of animals as organ donors

for humans (the animals from which theorgans are taken are called "donor ani-mals", "source animals" or also "xeno-genic animals") opens up a new field inthe use of animals and must thereforebe considered very thoroughly. Unfa-vourable consequences for the animalscan occur mainly in three areas:Introduction of heterogeneous genes:

In order to improve the tissular toler-ance and thus to reduce the rejectionreactions, human genes have to be in-troduced into the genome of the donoranimals. Therefore the questions thatarise with every transgenic animal haveto be asked: Do the transferred gene orgenes cause changes in appearance, thebehaviour or other characteristics of theanimal? Does it cause the animal painand suffering? In comparison with thecreation of transgenic animals for re-search purposes by the means used upuntil now, the amount of the foreigngenetic material introduced for thexenotransplantation can playa role.Housing conditions: Animals intend-

ed to be used as organ donors must beabsolutely free not only from pathogen-ic germs but also from potentially path-ogenic germs of all kinds. The breed-ing, care and housing of the animals aretherefore possible only under strict con-ditions of isolation. This requires aclosed, isolated unit where the feed andother materials are passed in through anisolation chamber, only after they havebeen sterilised. The animal keepers alsohave to pass through an isolation cham-ber. These conditions are already re-quired today in breeding and housingunits for experimental animals wherebreeding animals and laboratory ani-mals have to be kept free from patho-genic germs. Under these restrictiveconditions, however, the animals aredeprived of all contact with a naturalenvironment, which can cause themstress. The specific design of the cagesor other forms of housing for the par-ticular animal species and the provisionof various suitable diversions are in-

24

tended to increase the quality of theirenvironment and to make social contactpossible for the animals.Preclinical development phase: In

this phase, major ethical problems canarise as far as the animals are con-cerned, especially with the xenotrans-plantation of organs. Before the trans-plantation of an animal organ in humanscan be justified according to medical-ethical criteria, test transplantations ofthe organ from one animal species toanother must have shown satisfactoryresults. In these tests, besides the effectson the animal due to the surgical inter-vention necessary for the transplanta-tion, massive adverse effects on thehealth of the recipient animals as a re-sult of the reaction to the foreign tissuecan occur, so that they die or have to beput to sleep. This will be the case at leastuntil the technology has been improvedand perfected.Consistent observance of absolute

respect for all life would make the useof animals as organ donors impossible.However, this would also mean that inour society the handling and use of an-imals, in every respect, and not only inregard to their use in animal experi-ments and for xenotransplantation,would have to be considered anew.

In order to respect their dignity as liv-ing creatures, any intervention into thewell-being and the life of animals mustnot be undertaken without convincingjustification. At the present time it isstill not possible to estimate the futureimportance of xenotransplantation. Therisks of the transmission of germs path-ogenic for humans cannot be assessedconclusively, and many fields of tech-nology have to be developed further. Itcan therefore not be said with certaintywhether the objective that is beingaimed for can be achieved and whetherthese animal experiments can thus ful-fil their purpose. However, this uncer-tainty is a weakness that applies in anytype of research.With the xenotransplantation of ani-

mal organs, the interests of Man andanimals are diametrically opposed andhave to be carefully weighed againsteach other in each individual case. Inthe development phase of this procedureit is not possible to make a general ap-praisal of the admissibility of the use

of animals. Special recognition must begiven to the following principal aspects,in the sense of a weighing-up of thebenefits and the disadvantages:~ the possible benefits (quality of life,life expectancy) for the organ recipient,in the best case;~ the suffering imposed on the recipi-ent animal due to the experiment, in thepreclinical phase;~ the introduction of a large number ofhuman genes into the genome of theanimals and the possible consequencesfor their well-being;~ the living conditions of the donoranimals that are necessary to ensuretheir state of health as required for thetransplantation;~ the death of many animals, in itself.

KorrespondenzadresseProf. H. U. Bertschinger, PrasidentOberhittnauerstr. 26CH-8330 PfaffikonTel. und Fax: +41 9402248

ALTEX 17,1100