Stem Cells

For many decades, scientists working in the field of generative medicine sought ways of finding a ready and plentiful supply of human stem cells in the hope that these could be used to treat a range of degenerative diseases. Last week, the Cambridge scientist, Sir John Gurdon, and Professor Shinya Yamanaka of Japan were jointly awarded the Nobel Prize for Medicine for bringing this dream a step nearer. Forty years before Dolly the sheep, Sir John cloned a frog by a similar cloning technique, and Professor Yamanaka conducted experiments in 2005 that showed that it was possible to re-programme a skin cell to turn it into a stem cell.

What are stem cells? All (or almost all) of the tens of million of cells in the human body are similar in structure, having a nucleus with the same DNA containing the same information that gives you your inherited characteristics and gives me mine. However, blood cells do not do the same job as nerve cells, which do not do the same job as muscle cells, and so on.

All the cells in the body are descendants of the original cell, the zygote or single-cell human embryo, but over time the cells have specialised to perform different functions in the body.

In contrast, a stem cell is a cell that remains flexible in what it can do. It can both reproduce itself and give rise to different kinds of specialist cells. For some time, scientists have hoped that stem cells might be useful in medicine, helping to replace or repair damaged tissue.

Stem cells are found in bone marrow, the cornea and the blood in a baby’s umbilical cord, and these have been extracted for use in a variety of treatments. However, the most controversial and ethically problematic source of stem cells is the human embryo. In 1998, a line of stem cells was created by destroying a human embryo, and since that time many hundreds of embryos have been destroyed in attempts to create more stem-cell lines. For anyone who accepts (or even suspects) that a human life begins at fertilisation, it is clearly unethical to kill an embryonic human being simply to “harvest” his or her cells.

The controversy over destroying human embryos for their stem cells is the background to Yamanaka’s work in Japan and the US. He was able to take ordinary adult cells (not adult stem cells, but ordinary skin cells) and turn them into cells which behave very like embryonic stem cells. This is the biological equivalent of turning base metal into gold.

From a humble skin cell, by switching on certain genes, Yamanaka was able to create a stem cell. This cell seems to have the advantages of embryonic stem cells (for example, being able to multiply easily) together with some of the ethical and practical advantages of adult stem cells (being taken from an adult). His experiment was both elegant science and ethical science.

In a New York Times interview, Yamanaka recounted an experience that changed his career - a glimpse down the microscope, at a friend’s fertility clinic, of one of the embryos stored there. He commented: “When I saw the embryo, I suddenly realised there was such a small difference between it and my daughters. I thought, we can’t keep destroying embryos for our research. There must be another way.” Although he did not oppose all embryo research, Yamanaka was motivated, at least in part, by a desire to find “another way”, and not just by political pressures, such as the restriction on funding embryo research imposed by President George W. Bush.

In the United Kingdom, there has never been any restriction on funding destructive embryo experimentation. Indeed, as each new and unethical form of experimentation has been suggested, the Government has rushed to permit it, including the creation of part-human part-non-human embryos, hybrids and also chimeras, made from the nucleus of a human being and the cytoplasm of a cow or a rabbit. Nothing came of these bizarre experiments, despite the exaggerated claims made about them at the time.

In contrast, Yamanaka’s experiment has been the basis of a whole new area of research, not with adult stem cells or embryonic stem cells, but with what are called iPS cells or “induced pluripotent stem cells”. These are stem cells created from ordinary adult cells, such as skin cells. This research is increasingly attracting funding both in this country and abroad. It is exciting science.

Are there, nevertheless, some ethical problems with iPS cells? Should we be cautious before welcoming this Nobel Prize? As with any technology, especially one that is potentially very powerful, the issue of iPS cells does raise ethical issues. Already they have been used to clone mice and create artificial sperm and eggs for use in mouse IVF. As human cloning, and other forms of in vitro manufacture of human lives, contradicts the dignity of procreation, it would clearly be wrong to use iPS cells for such purposes.

Another more immediate ethical problem with iPS research is that many scientists who are working with iPS cells are, at the same time, working with embryonic cells. There can be an inertia among scientists, and professional and personal attachments to older ways of doing things, even if they are unethical.

So a strongly ethical young scientist who wishes to work on iPS cells might find themselves in difficulties because of being asked to cooperate with embryonic stem-cell research. It is also true that stem-cell research is still a very young area of science, and we should not exaggerate the prospect of immediate treatments.

Adult stem cells are already used successfully in both established and experimental treatments, but the revolution in treatment for which many are hoping is still some way off.

It is the job of a bioethicist to make qualifications and to point out potential difficulties, but none of these should obscure the fundamentally positive contribution of Yamanaka’s work. This Nobel Prize recognises a great scientific breakthrough, but it is equally an achievement of great ethical significance. It offers a new and promising approach to stem-cell research which need not involve the destruction of human embryos.

The occasional conflicts of scientists and ethicists, and the adoption of unethical practices in the name of science, should not be allowed to obscure the fundamentally ethical character of the scientific endeavour and the positive contribution that religion has had in sustaining the search for knowledge through the centuries. This Nobel Prize shows science as it can be, science at its best: both beautiful and ethical.

Professor David Albert Jones is director of the Anscombe Bioethics Centre in Oxford.

The value of adult (somatic) stem cell therapy has been established for many years. The most widespread application is bone-marrow transplantation, which makes use of immunological and blood stem cells to replenish white blood cells, red blood cells, platelets, and immunologically active cells in the transplant recipient. Other therapies include procedures that transfer stem cells from one part of a patient's body to an injured area of the same patient in order to assist healing. Table 2 below lists some of the many therapies that have been devised and are still being studied that make use of bone marrow stem cells.

Stem cell therapy became controversial when some scientists claimed that cells extracted from human blastocysts created through in vitro fertilization would provide even more useful treatments. During this controversy the opposition of the Catholic Church to the use in research of human embryos was portrayed as a dangerous impediment to medical progress. As time has passed, an ever-increasing number of adult stem-cell therapies have proven valuable: to date no cures or effective treatments using embryonic stem cells exist. As Dr. Jones has noted above, Professor Yamanaka's technique has significantly advanced the potential of adult stem cells, by making it possible to reprogram adult cells - not necessarily stem cells - into cells with the same potential as stem cells.

"Adult Stem Cells for Tissue Repair" The New England Journal of Medicine.
Volume 349:570-582, August 7, 2003,Number 6

Contrast between: 1. Professor Yamanaka's Method
of Induced Pluripotent Stem Cells; and
2. Embryonic Stem-Cell Research

The Catholic Church unequivocally supports somatic stem cell research, that is, research that does not result in the destruction of human embryos. As Pope Benedict XVI has summarized:

[...] somatic stem-cell research also deserves approval and encouragement when it felicitously combines scientific knowledge, the most advanced technology in the biological field and ethics that postulate respect for the human being at every stage of his or her existence. The prospects opened by this new chapter in research are fascinating in themselves, for they give a glimpse of the possible cure of degenerative tissue diseases that subsequently threaten those affected with disability and death. How is it possible not to feel the duty to praise all those who apply themselves to this research and all who support the organization and cover its expenses?

Address of His Holiness Benedict XVI to the Participants in the Symposium on the Theme: "Stem Cells: What Future for Therapy?"organized by the Pontifical Academy for Life. Saturday, 16 September 2006

Embryonic stem cell research that creates, dissects, and destroys human embryos is specifically condemned in (CDF) Dignitas Personae 30.

51. The way humanity treats the environment influences the way it treats itself, and vice versa. This invites contemporary society to a serious review of its life-style, which, in many parts of the world, is prone to hedonism and consumerism, regardless of their harmful consequences¹²². What is needed is an effective shift in mentality which can lead to the adoption of new life-styles “in which the quest for truth, beauty, goodness and communion with others for the sake of common growth are the factors which determine consumer choices, savings and investments”¹²³.	51. Rationes quibus homo naturam tractat in rationes influunt quibus se ipsum tractat ac vicissim. Hoc societatem hodiernam monet ut serio animo suum vivendi genus mutet, quod multis in mundi partibus ad hedonismum et consumismum inclinatur, dum indifferens manet erga damna ex iis derivantia [122]. Necessaria est certa mentis mutatio quae nos inducat ut novas vitae rationes sumamus, « in quibus conquisitio veri pulchri boni et communio cum ceteris hominibus propter communem progressionem electiones efficiant consumptionum, compendiorum, pecuniae collocationum » [123].
¹²² cf. John Paul II, Message for the 1990 World Day of Peace, 13: loc. cit., 154-155. ¹²³ John Paul II, Encyclical Letter Centesimus Annus, 36: loc. cit., 838-840.
Every violation of solidarity and civic friendship harms the environment, just as environmental deterioration in turn upsets relations in society. Nature, especially in our time, is so integrated into the dynamics of society and culture that by now it hardly constitutes an independent variable. Desertification and the decline in productivity in some agricultural areas are also the result of impoverishment and underdevelopment among their inhabitants. When incentives are offered for their economic and cultural development, nature itself is protected. Moreover, how many natural resources are squandered by wars! Peace in and among peoples would also provide greater protection for nature. The hoarding of resources, especially water, can generate serious conflicts among the peoples involved. Peaceful agreement about the use of resources can protect nature and, at the same time, the well-being of the societies concerned.	Omnis laesio solidarietatis et amicitiae civium damna in naturam inferunt, quemadmodum naturae corruptio vicissim in sociales relationes displicentiam inducit. Natura, praesertim nostra aetate, sic implicatur socialibus et culturalibus inceptis ut fere non constituat quandam variabilitatem independentem. Vastitas procedens et productionis pauperies quarundam regionum agricolarum ab indigentibus procurantur gentibus inibi incolentibus earumque exigua progressione. Si progressio oeconomica culturalisque harum gentium stimulatur, natura etiam protegitur. Insuper, quot subsidia naturalia bellis vastantur! Pax populorum et inter populos sinit quoque ut maior naturae tutela foveatur. Coëmptio opum, praesertim aquae, apud gentes his rebus implicatas graves contentiones gignere potest. Pacifica consensio de subsidiorum usu naturam servare simulque prosperitatem societatibus quarum interest afferre potest.
*The Church has a responsibility towards creation* and she must assert this responsibility in the public sphere. In so doing, she must defend not only earth, water and air as gifts of creation that belong to everyone. She must above all protect mankind from self-destruction. There is need for what might be called a human ecology, correctly understood. The deterioration of nature is in fact closely connected to the culture that shapes human coexistence: when “human ecology”¹²⁴ is respected within society, environmental ecology also benefits. Just as human virtues are interrelated, such that the weakening of one places others at risk, so the ecological system is based on respect for a plan that affects both the health of society and its good relationship with nature.	Ecclesia erga creationem conscientae officio tenetur, quod etiam publice ostendere debet. Sic agendo, defendere debet non solum terram, aquam et aërem tamquam dona creationis ad omnes pertinentia; verum etiam ante omnia hominem servare debet contra ipsius exstinctionem. Necessarium est ut quaedam sit species oecologiae hominis, recto modo intellecta. Naturae corruptio cum cultura arte coniungitur quae humanum convictum fingit: cum « oecologia humana » [124] intra societatem colitur, etiam naturae oecologia beneficiis afficitur. Quemadmodum humanae virtutes sese mutuo communicant, ut alterius debilitas vulnus inferat etiam in alios, ita oecologicus ordo servato consilio regitur quod tum ad sanum convictum, tum ad consentaneam cum natura necessitudinem attinet.
¹²⁴ Ibid., 38: loc. cit., 840-841; Benedict XVI, Message for the 2007 World Day of Peace, 8: loc. cit., 779.
In order to protect nature, it is not enough to intervene with economic incentives or deterrents; not even an apposite education is sufficient. These are important steps, but the decisive issue is the overall moral tenor of society. If there is a lack of respect for the right to life and to a natural death, if human conception, gestation and birth are made artificial, if human embryos are sacrificed to research, the conscience of society ends up losing the concept of human ecology and, along with it, that of environmental ecology. It is contradictory to insist that future generations respect the natural environment when our educational systems and laws do not help them to respect themselves. The book of nature is one and indivisible: it takes in not only the environment but also life, sexuality, marriage, the family, social relations: in a word, integral human development. Our duties towards the environment are linked to our duties towards the human person, considered in himself and in relation to others. It would be wrong to uphold one set of duties while trampling on the other. Herein lies a grave contradiction in our mentality and practice today: one which demeans the person, disrupts the environment and damages society.	Ad tuendam naturam non sufficit ut quaedam aut nulla oeconomica subsidia praebeantur, ne congrua quidem instructio sufficit. Instrumenta sunt haec magni ponderis, sed praecipua quaestio inest in universa moralis societatis firmitudine. Si vitae mortisque naturalis ius non observatur, si artificiosa efficitur conceptio, gestatio et nativitas hominis, si humani embryones vestigationi immolantur, accidit ut communis conscientia oecologiae humanae ac simul etiam oecologiae naturae sensum amittat. Contradictorium est a novis generationibus naturae observantiam postulare, cum institutio legesque suum ipsarum cultum non adiuvant. Liber naturae unus est et indivisibilis, tam ex parte naturae quam ex parte vitae, sexualitatis, matrimonii, familiae, relationum socialium, denique humanae integraeque progressionis. Officia nostra erga rerum naturam cum nostris muneribus nectuntur quae personam respiciunt, quae per se ipsa consideratur et cum aliis relata. Non licet alia exigere et alia conculcare. Haec gravis est antinomia mentis hodiernique moris quae personam deprimit, naturam turbat ac damna societati affert.

74. A particularly crucial battleground in today’s cultural struggle between the supremacy of technology and human moral responsibility is the field of bioethics, where the very possibility of integral human development is radically called into question. In this most delicate and critical area, the fundamental question asserts itself forcefully: is man the product of his own labours or does he depend on God? Scientific discoveries in this field and the possibilities of technological intervention seem so advanced as to force a choice between two types of reasoning: reason open to transcendence or reason closed within immanence. We are presented with a clear either/ or. Yet the rationality of a self-centred use of technology proves to be irrational because it implies a decisive rejection of meaning and value. It is no coincidence that closing the door to transcendence brings one up short against a difficulty: how could being emerge from nothing, how could intelligence be born from chance?¹⁵³	74. Super primario decretorioque argumento culturalis inter absolutam technicam et hominis moralem responsalitatem certaminis hodiernis temporibus praecipuum occupat locum bioethica, in qua facultas ipsa humanae integraeque progressionis assequendae in discrimine prorsus versatur. De re agitur subtilissima decretoriaque, ex qua dramatica vi praecipua quaestio oritur: utrum homo a se ipse producatur an a Deo pendeat. Scientifica hac in provincia inventa facultatesque technice agendi tam aucta videntur, ut inter duas rationalitates selectio sit facienda: scilicet rationis transcendentiae patentis aut rationis in immanentiam conclusae. Coram sumus illo aut aut decretorio. Technicae actionis rationalitas, quae in se vertitur, irrationalis tamen deprehenditur, quia significationis bonique repudiationem secum fert. Non sine causa transcendentia denegata cum difficultate confligit cogitandi quo pacto ex nihilo « ens » ortum sit atque fortuito exstiterit intellectus [153].
¹⁵³ Cf. Benedict XVI, Address to the Participants in the Fourth National Congress of the Church in Italy, Verona, 19 October 2006; Id., Homily at Mass, Islinger Feld, Regensburg, 12 September 2006.]
Faced with these dramatic questions, reason and faith can come to each other’s assistance. Only together will they save man. Entranced by an exclusive reliance on technology, reason without faith is doomed to flounder in an illusion of its own omnipotence. Faith without reason risks being cut off from everyday life¹⁵⁴.	Hisce coram dramaticis quaestionibus ratio fidesque sibi mutuum adiumentum suppeditant. Una simul tantum hominem servabunt. Technica arte agenda pellecta, sine fide ratio in falsam suae omnipotentiae speciem est casura. Fides sine ratione periculum adit ne a certa personarum vita abstrahatur [154].
¹⁵⁴ Cf. Cong.Doct.Faith, Instruction on certain bioethical questions Dignitas Personae AAS 100 (2008), 858-887.
75. Paul VI had already recognized and drawn attention to the global dimension of the social question¹⁵⁵	75. Paulus VI mundanum iam socialis quaestionis prospectum indicavit [155].
¹⁵⁵ Cf. Encyclical Letter Populorum Progressio, 3: loc. cit., 258.
Following his lead, we need to affirm today that the social question has become a radically anthropological question, in the sense that it concerns not just how life is conceived but also how it is manipulated, as bio-technology places it increasingly under man’s control. In vitro fertilization, embryo research, the possibility of manufacturing clones and human hybrids: all this is now emerging and being promoted in today’s highly disillusioned culture, which believes it has mastered every mystery, because the origin of life is now within our grasp. Here we see the clearest expression of technology’s supremacy. In this type of culture, the conscience is simply invited to take note of technological possibilities. Yet we must not underestimate the disturbing scenarios that threaten our future, or the powerful new instruments that the “culture of death” has at its disposal. To the tragic and widespread scourge of abortion we may well have to add in the future — indeed it is already surreptiously present — the systematic eugenic programming of births. At the other end of the spectrum, a pro-euthanasia mindset is making inroads as an equally damaging assertion of control over life that under certain circumstances is deemed no longer worth living. Underlying these scenarios are cultural viewpoints that deny human dignity. These practices in turn foster a materialistic and mechanistic understanding of human life. Who could measure the negative effects of this kind of mentality for development? How can we be surprised by the indifference shown towards situations of human degradation, when such indifference extends even to our attitude towards what is and is not human? What is astonishing is the arbitrary and selective determination of what to put forward today as worthy of respect. Insignificant matters are considered shocking, yet unprecedented injustices seem to be widely tolerated. While the poor of the world continue knocking on the doors of the rich, the world of affluence runs the risk of no longer hearing those knocks, on account of a conscience that can no longer distinguish what is human. God reveals man to himself; reason and faith work hand in hand to demonstrate to us what is good, provided we want to see it; the natural law, in which creative Reason shines forth, reveals our greatness, but also our wretchedness insofar as we fail to recognize the call to moral truth.	Dum eandem quam ipse tenemus semitam, autumare hodie oportet socialem quaestionem funditus factam esse anthropologicam quaestionem, eo quod ipsam afficit rationem non modo intellegendi, verum etiam vitam tractandi, quae magis ac magis in hominis manibus per biotechnologica artificia ponitur. Fecundatio in vitro, embryonum vestigatio, clonandi, ut aiunt, facultas atque humana hybridatio in hodierna cultura, omni elatione destituta, oriuntur et promoventur, quae putat se cuncta mysteria detegisse, quandoquidem vitae radix iam attingitur. Technicae artis absolutismus suam hic summam manifestationem reperit. In hoc culturae genere ad solam technicam facultatem obtinendam conscientia vocatur. Imminui tamen non possunt rerum prospectus, qui hominis futurum aevum acriter afficient necnon nova efficacia instrumenta, quae « mortis culturae » praesto sunt. Abortus latae, funestae quidem internecioni addi proximos in annos potest, quod iam furtim in ipso germine adest, praestituta eugenetica natorum temperatio. Ex adverso capit incrementum mens euthanasica, quae est non minus iniusta quam vitae dominandae ostentatio, quae ad certas quasdam condiciones actu digna non consideratur. Propter has opinationes quaedam reperiuntur culturae, quae hominis dignitatem denegant. Hae autem res humanae vitae materialia mechanicisticaque iudicia augent. Quis negativos effectus huiusmodi de progressu mentis metiri poterit? Quomodo de humanarum condicionum abiectarum neglegentia mirari possumus, si indifferens animus vel mores nostros designat, quod ad humanum atque inhumanum attinet? Admirationem movet inconsulta selectio illarum rerum quae hodierna aetate quae observentur dignae proponuntur. Statim minoribus rebus qui offenduntur, iidem incredibiles iniquitates multi tolerare videntur. Dum autem orbis terrarum pauperes ad ianuam adhuc pultant divitum, periculum est ne locuples mundus animadvertat pultatam ianuam, conscientia iam humanum non percipiente. Hominem Deus homini detegit; ratio fidesque sociatam operam conferunt ei bonum demonstrantes, dummodo illud ipse videre velit; naturalis lex, in qua creatrix Ratio splendet, hominis magnitudinem ostendit, verum etiam eius miseriam, cum ipse moralem dignitatem vocantem neglegit.
76. One aspect of the contemporary technological mindset is the tendency to consider the problems and emotions of the interior life from a purely psychological point of view, even to the point of neurological reductionism. In this way man’s interiority is emptied of its meaning and gradually our awareness of the human soul’s ontological depths, as probed by the saints, is lost. The question of development is closely bound up with our understanding of the human soul, insofar as we often reduce the self to the psyche and confuse the soul’s health with emotional well-being. These over-simplifications stem from a profound failure to understand the spiritual life, and they obscure the fact that the development of individuals and peoples depends partly on the resolution of problems of a spiritual nature. Development must include not just material growth but also spiritual growth, since the human person is a “unity of body and soul”¹⁵⁶,	76. In horum temporum technicisticis mentibus inclinatio illa reperitur quaestiones interiorisque vitae motus per psychologicam rationem considerandi, usque ad neurologicam quandam deminutionem. Intima sic hominis pars exinanitur atque ontologicae animae humanae soliditatis conscientia, una cum altitudinibus, quas Sancti animadverterunt, gradatim amittitur. Provectus etiam quaestio cum nostra de hominis anima opinatione arte nectitur, eo quod nostrum « ego » ad psychen crebro reducitur et animae salus cum emotionis bono miscetur. Quae remissiones in haud intellecta spiritali vita penitus consistunt atque efficiunt ne agnoscatur hominis populorumque progressum e contrario solutis ex quaestionibus pendere spiritalis naturae. Profectus, praeter materialem, spiritalem progressionem complecti debet, quia homo est « corpore et anima unus » [156],
¹⁵⁶ Second Vatican Ecumenical Council, Pastoral Constitution on the Church in the Modern World Gaudium et Spes, 14.
born of God’s creative love and destined for eternal life. The human being develops when he grows in the spirit, when his soul comes to know itself and the truths that God has implanted deep within, when he enters into dialogue with himself and his Creator. When he is far away from God, man is unsettled and ill at ease. Social and psychological alienation and the many neuroses that afflict affluent societies are attributable in part to spiritual factors. A prosperous society, highly developed in material terms but weighing heavily on the soul, is not of itself conducive to authentic development. The new forms of slavery to drugs and the lack of hope into which so many people fall can be explained not only in sociological and psychological terms but also in essentially spiritual terms. The emptiness in which the soul feels abandoned, despite the availability of countless therapies for body and psyche, leads to suffering. There cannot be holistic development and universal common good unless people’s spiritual and moral welfare is taken into account, considered in their totality as body and soul.	ex Dei creatoris amore ortus, ad vitam aeternam destinatur. Homo adulescit cum crescit in spiritu, cum eius anima se ipsa novit veritatesque quas Deus in germine in ea posuit, cum dialogum secum ipse et cum Creatore instituit. Procul a Deo inquietus est homo infirmusque. Socialis psychologicaque alienatio et tot nervorum angores quibus locuples societas afficitur, ad causas etiam referunt spiritalis indolis. Abundantia rerum munita societas, materialiter prospera, sed animam gravans, veram progressionem ex se non petit. Nova medicamentorum stupefactivorum servitutis genera animorumque abiectiones in quae tot personae incidunt non modo sociologice psychologiceque, sed potissimum spiritaliter, explicari possunt. Vacuitas in qua anima deseritur, licet complures corporis animique praesto sint curationes, dolorem gignit. Plena progressio ac bonum universale commune, dempto spiritali moralique personarum bono, non dantur, quae in earum integritate animae corporisque considerantur.
77. The supremacy of technology tends to prevent people from recognizing anything that cannot be explained in terms of matter alone. Yet everyone experiences the many immaterial and spiritual dimensions of life. Knowing is not simply a material act, since the object that is known always conceals something beyond the empirical datum. All our knowledge, even the most simple, is always a minor miracle, since it can never be fully explained by the material instruments that we apply to it. In every truth there is something more than we would have expected, in the love that we receive there is always an element that surprises us. We should never cease to marvel at these things. In all knowledge and in every act of love the human soul experiences something “over and above”, which seems very much like a gift that we receive, or a height to which we are raised. The development of individuals and peoples is likewise located on a height, if we consider the spiritual dimension that must be present if such development is to be authentic. It requires new eyes and a new heart, capable of rising above a materialistic vision of human events, capable of glimpsing in development the “beyond” that technology cannot give. By following this path, it is possible to pursue the integral human development that takes its direction from the driving force of charity in truth.	77. Artis technicae absolutismus efficit ut percipiendi adimatur facultas id quod materia una non explicatur. Attamen homines cuncti tot species immateriales spiritalesque suae vitae experiuntur. Cognoscere non est tantum materiale quiddam, quandoquidem id quod cognoscitur semper aliquid abscondit, quod empirica elementa praetergreditur. Cognitio omnis, etiam planissima, parvum usque est prodigium, quoniam materialibus instrumentis, quae adhibemus, penitus numquam explicatur. In omni veritate plus adest quam quod suspicari possumus; recepto in amore semper inest aliquid quod nos obstupefacit. Numquam haec propter prodigia mirari desinere debemus. In omni cognitione amorisque actu hominis anima « plus » experitur, quod recepto dono, cuidam altitudini ad quam elevamur, multum assimilatur. Hominis populorumque etiam progressio in simili altitudine locatur, si spiritalem rationem consideramus, quae necessario hunc profectum designare debet, ut ipse verus sit. Novos oculos corque novum postulat, ut materialistica opinatio superetur humanorum eventuum atque in progressu illud « ultra » conspiciatur, quod technica ars suppeditare non potest. Hac ratione integra progressio illa humana obtineri potest, quae caritatis in veritate vi propulsuque suam dirigentem reperit regulam.

The term cloning describes a number of different processes that can be used to produce genetically identical copies of a biological entity. The copied material, which has the same genetic makeup as the original, is referred to as a clone. Researchers have cloned a wide range of biological materials, including genes, cells, tissues and even entire organisms, such as a sheep.

Do clones ever occur naturally?

Yes. In nature, some plants and single-celled organisms, such as bacteria, produce genetically identical offspring through a process called asexual reproduction. In asexual reproduction, a new individual is generated from a copy of a single cell from the parent organism.

Natural clones, also known as identical twins, occur in humans and other mammals. These twins are produced when a fertilized egg splits, creating two or more embryos that carry almost identical DNA. Identical twins have nearly the same genetic makeup as each other, but they are genetically different from either parent.

What are the types of artificial cloning?

There are three different types of artificial cloning: gene cloning, reproductive cloning and therapeutic cloning.

Gene cloning produces copies of genes or segments of DNA. Reproductive cloning produces copies of whole animals. Therapeutic cloning produces embryonic stem cells for experiments aimed at creating tissues to replace injured or diseased tissues.

Gene cloning, also known as DNA cloning, is a very different process from reproductive and therapeutic cloning. Reproductive and therapeutic cloning share many of the same techniques, but are done for different purposes.

What sort of cloning research is going on at NHGRI?

Gene cloning is the most common type of cloning done by researchers at NHGRI. NHGRI researchers have not cloned any mammals and NHGRI does not clone humans.

How are genes cloned?

Researchers routinely use cloning techniques to make copies of genes that they wish to study. The procedure consists of inserting a gene from one organism, often referred to as “foreign DNA,” into the genetic material of a carrier called a vector. Examples of vectors include bacteria, yeast cells, viruses or plasmids, which are small DNA circles carried by bacteria. After the gene is inserted, the vector is placed in laboratory conditions that prompt it to multiply, resulting in the gene being copied many times over.

How are animals cloned?

In reproductive cloning, researchers remove a mature somatic cell, such as a skin cell, from an animal that they wish to copy. They then transfer the DNA of the donor animal's somatic cell into an egg cell, or oocyte, that has had its own DNA-containing nucleus removed.

Researchers can add the DNA from the somatic cell to the empty egg in two different ways. In the first method, they remove the DNA-containing nucleus of the somatic cell with a needle and inject it into the empty egg. In the second approach, they use an electrical current to fuse the entire somatic cell with the empty egg.

In both processes, the egg is allowed to develop into an early-stage embryo in the test-tube and then is implanted into the womb of an adult female animal.

Ultimately, the adult female gives birth to an animal that has the same genetic make up as the animal that donated the somatic cell. This young animal is referred to as a clone. Reproductive cloning may require the use of a surrogate mother to allow development of the cloned embryo, as was the case for the most famous cloned organism, Dolly the sheep.

What animals have been cloned?

Over the last 50 years, scientists have conducted cloning experiments in a wide range of animals using a variety of techniques. In 1979, researchers produced the first genetically identical mice by splitting mouse embryos in the test tube and then implanting the resulting embryos into the wombs of adult female mice. Shortly after that, researchers produced the first genetically identical cows, sheep and chickens by transferring the nucleus of a cell taken from an early embryo into an egg that had been emptied of its nucleus.

It was not until 1996, however, that researchers succeeded in cloning the first mammal from a mature (somatic) cell taken from an adult animal. After 276 attempts, Scottish researchers finally produced Dolly, the lamb from the udder cell of a 6-year-old sheep. Two years later, researchers in Japan cloned eight calves from a single cow, but only four survived.

Besides cattle and sheep, other mammals that have been cloned from somatic cells include: cat, deer, dog, horse, mule, ox, rabbit and rat. In addition, a rhesus monkey has been cloned by embryo splitting.

Have humans been cloned?

Despite several highly publicized claims, human cloning still appears to be fiction. There currently is no solid scientific evidence that anyone has cloned human embryos.

In 1998, scientists in South Korea claimed to have successfully cloned a human embryo, but said the experiment was interrupted very early when the clone was just a group of four cells. In 2002, Clonaid, part of a religious group that believes humans were created by extraterrestrials, held a news conference to announce the birth of what it claimed to be the first cloned human, a girl named Eve. However, despite repeated requests by the research community and the news media, Clonaid never provided any evidence to confirm the existence of this clone or the other 12 human clones it purportedly created.

In 2004, a group led by Woo-Suk Hwang of Seoul National University in South Korea published a paper in the journal Science in which it claimed to have created a cloned human embryo in a test tube. However, an independent scientific committee later found no proof to support the claim and, in January 2006, Science announced that Hwang's paper had been retracted.

From a technical perspective, cloning humans and other primates is more difficult than in other mammals. One reason is that two proteins essential to cell division, known as spindle proteins, are located very close to the chromosomes in primate eggs. Consequently, removal of the egg's nucleus to make room for the donor nucleus also removes the spindle proteins, interfering with cell division. In other mammals, such as cats, rabbits and mice, the two spindle proteins are spread throughout the egg. So, removal of the egg's nucleus does not result in loss of spindle proteins. In addition, some dyes and the ultraviolet light used to remove the egg's nucleus can damage the primate cell and prevent it from growing.

Do cloned animals always look identical?

No. Clones do not always look identical. Although clones share the same genetic material, the environment also plays a big role in how an organism turns out.

For example, the first cat to be cloned, named Cc, is a female calico cat that looks very different from her mother. The explanation for the difference is that the color and pattern of the coats of cats cannot be attributed exclusively to genes. A biological phenomenon involving inactivation of the X chromosome (See sex chromosome) in every cell of the female cat (which has two X chromosomes) determines which coat color genes are switched off and which are switched on. The distribution of X inactivation, which seems to occur randomly, determines the appearance of the cat's coat.

What are the potential applications of cloned animals?

Reproductive cloning may enable researchers to make copies of animals with the potential benefits for the fields of medicine and agriculture.

For instance, the same Scottish researchers who cloned Dolly have cloned other sheep that have been genetically modified to produce milk that contains a human protein essential for blood clotting. The hope is that someday this protein can be purified from the milk and given to humans whose blood does not clot properly. Another possible use of cloned animals is for testing new drugs and treatment strategies. The great advantage of using cloned animals for drug testing is that they are all genetically identical, which means their responses to the drugs should be uniform rather than variable as seen in animals with different genetic make-ups.

After consulting with many independent scientists and experts in cloning, the U.S. Food and Drug Administration (FDA) decided in January 2008 that meat and milk from cloned animals, such as cattle, pigs and goats, are as safe as those from non-cloned animals. The FDA action means that researchers are now free to using cloning methods to make copies of animals with desirable agricultural traits, such as high milk production or lean meat. However, because cloning is still very expensive, it will likely take many years until food products from cloned animals actually appear in supermarkets.

Another application is to create clones to build populations of endangered, or possibly even extinct, species of animals. In 2001, researchers produced the first clone of an endangered species: a type of Asian ox known as a guar. Sadly, the baby guar, which had developed inside a surrogate cow mother, died just a few days after its birth. In 2003, another endangered type of ox, called the Banteg, was successfully cloned. Soon after, three African wildcats were cloned using frozen embryos as a source of DNA. Although some experts think cloning can save many species that would otherwise disappear, others argue that cloning produces a population of genetically identical individuals that lack the genetic variability necessary for species survival.

Some people also have expressed interest in having their deceased pets cloned in the hope of getting a similar animal to replace the dead one. But as shown by Cc the cloned cat, a clone may not turn out exactly like the original pet whose DNA was used to make the clone.

What are the potential drawbacks of cloning animals?

Reproductive cloning is a very inefficient technique and most cloned animal embryos cannot develop into healthy individuals. For instance, Dolly was the only clone to be born live out of a total of 277 cloned embryos. This very low efficiency, combined with safety concerns, presents a serious obstacle to the application of reproductive cloning.

Researchers have observed some adverse health effects in sheep and other mammals that have been cloned. These include an increase in birth size and a variety of defects in vital organs, such as the liver, brain and heart. Other consequences include premature aging and problems with the immune system. Another potential problem centers on the relative age of the cloned cell's chromosomes. As cells go through their normal rounds of division, the tips of the chromosomes, called telomeres, shrink. Over time, the telomeres become so short that the cell can no longer divide and, consequently, the cell dies. This is part of the natural aging process that seems to happen in all cell types. As a consequence, clones created from a cell taken from an adult might have chromosomes that are already shorter than normal, which may condemn the clones' cells to a shorter life span. Indeed, Dolly, who was cloned from the cell of a 6-year-old sheep, had chromosomes that were shorter than those of other sheep her age. Dolly died when she was six years old, about half the average sheep's 12-year lifespan.

What is therapeutic cloning?

Therapeutic cloning involves creating a cloned embryo for the sole purpose of producing embryonic stem cells with the same DNA as the donor cell. These stem cells can be used in experiments aimed at understanding disease and developing new treatments for disease. To date, there is no evidence that human embryos have been produced for therapeutic cloning.

The richest source of embryonic stem cells is tissue formed during the first five days after the egg has started to divide. At this stage of development, called the blastocyst, the embryo consists of a cluster of about 100 cells that can become any cell type. Stem cells are harvested from cloned embryos at this stage of development, resulting in destruction of the embryo while it is still in the test tube.

What are the potential applications of therapeutic cloning?

Researchers hope to use embryonic stem cells, which have the unique ability to generate virtually all types of cells in an organism, to grow healthy tissues in the laboratory that can be used replace injured or diseased tissues. In addition, it may be possible to learn more about the molecular causes of disease by studying embryonic stem cell lines from cloned embryos derived from the cells of animals or humans with different diseases. Finally, differentiated tissues derived from ES cells are excellent tools to test new therapeutic drugs.

What are the potential drawbacks of therapeutic cloning?

Many researchers think it is worthwhile to explore the use of embryonic stem cells as a path for treating human diseases. However, some experts are concerned about the striking similarities between stem cells and cancer cells. Both cell types have the ability to proliferate indefinitely and some studies show that after 60 cycles of cell division, stem cells can accumulate mutations that could lead to cancer. Therefore, the relationship between stem cells and cancer cells needs to be more clearly understood if stem cells are to be used to treat human disease.

What are some of the ethical issues related to cloning?

Gene cloning is a carefully regulated technique that is largely accepted today and used routinely in many labs worldwide. However, both reproductive and therapeutic cloning raise important ethical issues, especially as related to the potential use of these techniques in humans.

Reproductive cloning would present the potential of creating a human that is genetically identical to another person who has previously existed or who still exists. This may conflict with long-standing religious and societal values about human dignity, possibly infringing upon principles of individual freedom, identity and autonomy. However, some argue that reproductive cloning could help sterile couples fulfill their dream of parenthood. Others see human cloning as a way to avoid passing on a deleterious gene that runs in the family without having to undergo embryo screening or embryo selection.

Therapeutic cloning, while offering the potential for treating humans suffering from disease or injury, would require the destruction of human embryos in the test tube. Consequently, opponents argue that using this technique to collect embryonic stem cells is wrong, regardless of whether such cells are used to benefit sick or injured people.

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Cell Type	Tissue-Specific Location	Cells or Tissues Produced
Hematopoietic	Bone marrow, peripheral blood	Bone marrow and blood lymphohematopoetic cells
Mesenchymal stem cell	Bone marrow, peripheral blood	Bone, cartilage, tendon, adipose tissue, muscle, marrow stroma, neural cells
Neural stem cells	Ependymal cells, astrocytes (subventricular zone) of the CNS	Neurons, astrocytes, oligodendrocytes
Hepatic stem cells	In or near the terminal bile ductules (canals of Hering)	Oval cells that subsequently generate hepatocytes and ductular cells
Pancreatic Stem cells	Intra-islet Nestin positive cells, oval cells, duct cells	Beta cells
Skeletal muscle Stem cells	Muscle fibers	Skeletal muscle fibers
Stem cells of the skin (keratinocytes)	Basal layer of the epidermis, bulge zone of the hair follicles	Epidermis, hair follicles
Epithelial stem cells of the lung	Tracheal basal and mucus-secreting cells, bronciolar Clara cells, alveolar Type II pneumocyte	Mucous and ciliated cells, type I and II pneumocytes
Stem cells of the intestinal epithelium	Epithelial cells located around the base of each crypt	Paneth’s cells, brush-border enterocytes, mucus secreting goblet cells, enteroendocrine cells



_1. DAVID ALBERT JONES on STEM CELLS and the CATHOLIC CHURCH David Albert Jones



_3. THE CATHOLIC MAGISTERIUM on: Support of Stem Cell Research: Opposition to Destruction of Embryos Moloch offered infant sacrifice



_4. A BROADER PERSPECTIVE: CARITAS in VERITATE Pope Benedict XVI



_2. THE BIOLOGY of STEM CELLS Prof. Shinya Yamanaka

THE ETHICAL CELL: RESEARCH BREAKTHROUGH