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Report- Xenotransplantation


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#1 caliban

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Posted 19 August 2002 - 10:14 PM


What do you think about the attached report? (.PDF) from Health Canada?

I would be interested to hear your opinion about it and about xenotransplantation in general.

[Ok I admit I am also trying out the 'attach' feature with this ;) ]

Attached Files



#2 Bruce Klein

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Posted 22 August 2002 - 05:17 AM

Seems to me that growing organs from human stem cells would be better and maybe easier than xenotransplantation.

With human cloning there's no risk of rejection or cross-specis transmission of undetected animal infectious agents.

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#3 Lazarus Long

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Posted 23 August 2002 - 05:01 AM

The thing is BJ cloning a new heart for example to my specific genotype using stem cells might have me dead before the organ was big enough to carry the load of actually doing the work. I would need a clone that is kept cryogenically waiting for me so that I can yank it out of the tank and strip it for parts whenever I need them.
( I feel a plot coming on...) B)

What they are talking about are genetically "Modified" livestock that have "Human" genes inserted into their full genetic makeup so that function is mimicked reasonably well, they can be mass produced, and the factors that promote rejection for the human host can be suppressed in the donor species. Blood types can be inserted as another example.

This is not an unviable method. It bypasses the religious fanatics and brings the time and cost way down to accomplish the goal. These hearts, and lungs, and kidneys, etc could save a lot of lives while we go on debating the morality of Stem Cells from human sources.

But it does open Pandora's Box on the issue of uplifting other species. :o

On the upside there is little or no waste as the people who are not Vegans can eat the donor once they have harvested and frozen the rest of the useful organs. Talk about lending new meaning to the phrase:
"You are what you eat"... ;)

#4 Bruce Klein

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Posted 23 August 2002 - 05:18 AM

Laz,
I'm referring to cloning human cells from stem cells in order to make regenerative stem cells to inject into the hart, brain, or whatever.

Commonly refereed to as 'Therapeutic' cloning... which generates genetically compatible tissues (cells, and in theory, organs) for transplantation purposes.

I'm against growing individuals for spare parts or 'Reproductive' cloning, the creation of a genetically identical human being.


Tissue cloning could provide answers to degenerative diseases such as Parkinson's disease and conditions like leukemia, heart muscle damage and serious burns. It could make strong immunosuppressant drugs redundant. It could repair or replace whole organs, assist fertility treatment and avoid life-threatening 'mitochondrial' diseases

more cloning information

There's also the option of using adult stems cells to bypass using the embryonic stem cells.

The approach to embryonic stem (ES) cell therapy with the least ethical questions is utilization of stem cells already present in the adult body. Although seemingly each month researchers herald the discovery of new pluripotent stem cells, eventually we will reach a limit and alternate techniques will be required to continue ES therapy. Thankfully, recent advances in ES cloning may allow us to skip several ethical and technical obstacles. As reported in the August 2000 issue of Current Biology, mouse ES cells were isolated from cloned somatic adult nuclei (Munsie et al.). Put in rough therapeutic terms, this advance suggest we could eventually clone a person’s DNA in a new oocyte, perform any desired genetic manipulations, and grow replacement ES cells for in vivo re-implantation. This bypasses the ethical issues of using another fetus’ ES cells (or even growing a ‘late born twin’ for its bodyparts) and the immunology issues of cell rejection since the replacement ES cells will have patient’s exact DNA.  Link



#5 Lazarus Long

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Posted 23 August 2002 - 05:27 AM

I realize that, I am just feeling a little Holden Caufieldish after the "Catcher in the Rye" stint.

The point I am making about growing them wholesale from stem cells however is valid, it will take too long for an organ to get large enough for you to actually use in time, unless a brainless clone were in fact prepared beforehand. It would be the easiest method to grow the individual organs precisely because the body would function like a life support for the varous parts. Growing a full sized organ from Stem Cells implies you have met ALL the needs of that organ during its months to years of development.

BTW I'm not advocating doing this. I am just pointing out the "reason" some may want ot do it. Stem Cells are great if you have the TIME and have ANTICIPATED which organs to grow, well in advance of the emergancy need. Or are you just routinely replacing them? ;)

Anyway this is the reason that I emphasize that most of us will be cyborgs. The likelyhood is that we can use a modified stem cells to interface or cloak Artificial Organs that may work better than original once the R& D has time to learn from the first generations of implants. Plus the polymers research is fusing with Nano to create synthetics that may not offer the rejection/infection problem.

#6 caliban

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Posted 23 August 2002 - 09:44 PM

Woah, you two! [ph34r] [ph34r] Lemme remind you - the topic "stemcells" is right below!

To move this back on track: growing organs for transplantation from pigs is certainly a real possibility (happens every day) - growing organs from stem cells is still at least ten years into the future!

Ideally, at your 18th birthday you would be given "your" own genengenieerd pig: matched to your tissue type, reared in completely germ-free conditions, ready for the day you need a lung... or a pancreas... or a kidney... or a heart... or a brain...

The technology is already pretty advanced. (after all homotransplantation is done every day) The major drawback is as the report point out and as BJ mentioned, that governments are afraid about the transfer of pig-retroviruses to the human race.

Noow... I would still be interested to hear your opinions on that!

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#7 Bruce Klein

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Posted 24 August 2002 - 12:42 PM

Cal, I'm all for it... although I lack expertises in the specifics.

Heh, why did you strike out brain? Change your mind about that?

#8 Lazarus Long

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Posted 24 August 2002 - 05:36 PM

Basically the argument for for xenotransplantation is that it is easier, cheaper, and as Caliban points out already feasible. What needs to be understood is that basically we are in violent agreement.

We all agree that Stem Cell research is vital and should proceed in all the areas that BJ mentioned and others too, especially repair to nervous tissue and the brain. Anytime a seed organ can be constructed and begun outside the body but completed as an implant I think Stem Cells will be preferable. An example of this will be kidneys and lungs. As long as one is still functioning the second would have time to develop internally and come online to handle its share of metabolic function.

I also agree with Caliban however that xenotransplantation is important and it is present technology that needs enhancement. It also has far less of the associated socio-political memetic baggage. The animals can be genetically designed to fit a range of universal donation characteristics so as to avoid even having to have your "Personal Porky Pig" fitted with your specific genotype. Also livestock grows to maturity faster than humans.

It is also arguable that different species may provide different advantages, a Heart from a pig but maybe kidney from a sheep and so on. This is an area which still lacks basic research but it wouldn't be too difficult to fill in the gaps in a relatively short time.

I was making some snid jokes about eating the donor because I am a waste, not want not, kind of guy. But in all seriousness unless someone is planning on keeping their "Personal Organ Donor" on life support after removing its heart (for example) the rest of the potential organs (liver, lungs, pancreas, etc) would all be wasted. Not all organs in any one species will be usefull either. And the consumable flesh would now have to be treated as biohazardous waste, so what to do with the donor afterwards is an issue to think about.

Nevertheless, the rejection/infection problem is still pretty serious but there is more genetic tailoring going on for the donor species and better understanding of how to suppress rejection and prevent infection in the recipient everyday. Also Stem Cells may yet play into the ability to harvest them from other species the way we now do hormones.

Also it may be possible to alter the genetic signature of a donated organ from a different species by being able to prepare it and get it to match the key elements of the recipient's genetic makeeup. This last approach is years in the future but well within the realm of theoretical possibility.

Xenotransplantation has the advantage of making a vast quantity of donor organs available at significantly lower cost so that the procedures could then be more widely available to more people. It would also further our understanding of the process of transplantation and even if it is only buying its candidates a little time it is time that can be fruitful if at a later date a better option becomes available.

#9 Lazarus Long

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Posted 22 October 2002 - 03:56 PM

Monday, 21 October, 2002, 21:23 GMT 22:23 UK
Technique offers transplant hope

Posted Image
Pigs are the closest creatures genetically to humans

Changes in sperm engineering have allowed scientists to dramatically reduce the chances of transplanted pig organs being rejected by human patients.
A new technique suggests the success rate could be improved from 4% to 88%, according to the journal Proceedings of the National Academy of Sciences.

Until now researchers have relied on injecting a human gene into fertilised pig eggs to create animals whose organs can be harvested for use by humans.

But too often the animals fail to pick up the human gene and the organs have only been successful in 4% of cases.

But a team led by Marialuisa Lavitrano, at the University of Milano-Bicocca in Italy, have found that by modifying the DNA in pig sperm, rather than in the eggs, they can dramatically reduce the chances of organs being rejected.

Of 93 piglets produced from the treated sperm, 57% had the human gene in their organs.

When two unsuccessful fertilisations were excluded from the total of eight carried out, the success rate rose as high as 88%.

Furthermore the gene, called hDAF, was functional in multiple organs, including the heart, lung and kidney.

Laboratory tests showed that pig cells with the human protein produced by the gene were resistant to attack by the human immune system.

Ms Lavitrano's team had previously demonstrated the technique, sperm-mediated gene transfer (SMGT), on mice.

'High efficiency'

They wrote: "The pig is the most likely donor animal for xenotransplantation of organs, but may well require multiple transgenes to be a satisfactory donor for humans.

"Given the high efficiency of transgenesis, SMGT could greatly facilitate the production of such pigs."

The scientists made use of sperm's ability naturally to pick up DNA from the environment.

Fresh pig sperm was incubated in a medium that contained the human DNA.

The sperm naturally incorporated the human gene, which was then passed on to offspring after fertilisation.

The researchers added: "The possibility of generating transgenic pigs efficiently and reproducibly will, hopefully, not only be an advantage for creating multitransgene pig donor animals, but also enable strategies to fulfil many of the promises originally expected from the introduction of transgenic livestock."

#10 caliban

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Posted 25 October 2002 - 06:40 PM

Since we are back on topic... howabout a

[>] XENOTRANSPLANTATION TUTORIAL

to bring everyone back up to speed?

lol

#11 Lazarus Long

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Posted 26 October 2002 - 04:26 PM

Nice site Caliban! A little basic but that is good, better then talking over the heads of most people. But they should be careful about subtle miss information too. Here is a historical fallacy from the text.

Experiments involving xenotransplantation have been carried out since 1905 to present day with little success but new discoveries about the immune system of both humans and pigs will aid further research and the technique may reach clinical trials in the near future.


Actually the history of Xenotransplantation is much older and can be dated for modern science to the early blood transfusion experiments of the late 18th century. Some of the first attempts involved animal blood, and by the way were successful, but in the often frustrating way of early science weren't repeatable because the reasons "why things happen" were still a mystery.

#12 caliban

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Posted 27 October 2002 - 06:27 PM

Oh yes, that is a students website, very basic and not state of the art at all.
(Always curious if you have something nicer somewhere... Bob?)

the history of Xenotransplantation is much older

That is very possible. I know that the history of homotransplantiation certainly is.

Some of the first attempts involved animal blood, and by the way were successful,

That I find very hard to believe.

#13 Lazarus Long

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Posted 27 October 2002 - 10:07 PM

I am getting the link to Blundell's work later but his patients who survived didn't for long. He is givien most credit for today's beginning. [!]

Jean-Baptiste Denis and Richard Lower''s separate work is little known or documented due to its very early character but also because much of the work was destroyed in the still prevalent heresy fears after the initial work was announced. Remember the also knew little to nothing about sepsis. All subsequent attempts to use animal blood failed and were the result of extreme emergency, so your suspicions on this are valid. [hmm]

Please understand that the fervor of the opposition we are encountering today has a LONG historical fondation and this battle for legitimacy is yet barely engaged. I was referring to Blundell's work and was "speaking off the cuff" when I said the "late 18th century. Obviously, as the time line I am now presenting affirms, I confused what I had heard from a lecture some years ago and the origin is in fact almost two centuries earlier and the work was from a different independent pair of scientists.

I tried to edit this post four times and my computer creashed on it, after I got my machine up and running again I almost forgot how I had misprinted the original. But I finally remembered so I came back to correct it. [wacko]

There is another lesson to us in this not oftened told tale of the beginnings of Modern Medicine, and that is the Social Lesson. Medicine in hte West is fighting a lng war with fanatical fundamentalism that has consistently held back progress. This struggle is counter productive and a new approach is needed to accelerate our common cause.

Perhaps we should make Spin Doctoring a branch of Medicine ;)

The rest as they say is history. [ph34r]

HISTORY OF BLOOD TRANSFUSION

[http://members.redif...ank/History.htm

http://www.blood.co....es/e20hist.html


1628 English physician William Harvey discovers the circulation of blood. Shortly afterward, the earliest known blood transfusion is attempted.

1657 Sir Christopher Wren takes time out from designing cathedrals to inject some fluids into the circulation of animals, using equipment developed by William Harvey.
1665 The first recorded successful blood transfusion occurs in England: Physician Richard Lower keeps dogs alive by transfusion of blood from other dogs.

1666 In the same year that London burns, Richard Lower performs the first successful transfusion, albeit on an animal.

1667 Jean-Baptiste Denis in France and Richard Lower in England separately report successful transfusions from lambs to humans. Within ten years, transfusing the blood of animals to humans becomes prohibited by law, delaying transfusion advances for about 150 years.

1667 Samuel Pepys scribbles in his notes that experiments have been taking place at the Royal Society, transfusing blood from one dog to another.

1795 In Philadelphia an American physician, Philip Syng Physick, claims to perform the first human blood transfusion, although he does not publish this information.

1818 While poets like Keats, Shelley and Byron are all wandering around being romantic, Dr James Blundell is being altogether more practical and conducts transfusions in cases of haemorrhages after childbirth.

1818 James Blundell, a British obstetrician, performs the first successful transfusion of human blood to a patient for the treatment of postpartum hemorrhage. Using the patient's husband as a donor, he extracts approximately four ounces of blood from the husband's arm and, using a syringe, successfully transfuses the wife. Between 1825 and 1830, he performs 10 transfusions, five of which prove beneficial to his patients, and publishes these results. He also devises various instruments for performing transfusions and proposed rational indications.

1840 At St. George's School in London, Samuel Armstrong Lane, aided by consultant Dr. Blundell, performs the first successful whole blood transfusion to treat hemophilia.

1867 English surgeon Joseph Lister uses antiseptics to control infection during transfusions.

1873-1880 US physicians transfused milk (from cows, goats and humans)

1884 Saline infusion replaces milk as a “blood substitute” due to the increased frequency of adverse reactions to milk.

1900 Dr Karl Landsteiner, a leading doctor in Vienna, discovers that blood comes in 4 main groups - A, B, AB and O - and suddenly everybody realises why they've been going wrong for the last 272 years. The fourth, AB, is added by his colleagues A. Decastello and A. Sturli in 1902. Landsteiner receives the Nobel Prize for Medicine for this discovery in 1930.

1907 Hektoen suggests that the safety of transfusion might be improved by crossmatching blood between donors and patients to exclude incompatible mixtures. Reuben Ottenberg performs the first blood transfusion using blood typing and crossmatching in New York. Ottenberg also observed the mendelian inheritance of blood groups and recognized the “universal” utility of group O donors.

1908 French surgeon Alexis Carrel devises a way to prevent clotting by sewing the vein of the recipient directly to the artery of the donor. This vein-to-vein or direct method, known as anastomosis, is practiced by a number of physicians, among them J.B. Murphy in Chicago and George Crile in Cleveland. The procedure, however, proves unfeasible for blood transfusions, but paves the way for successful organ transplantation, for which Carrel receives the Nobel Prize in 1912.

1908 Moreschi describes the antiglobulin reaction.

1912 Roger Lee, a visiting physician at the Massachusetts General Hospital, along with Paul Dudley White, develops the Lee-White clotting time. Adding another important discovery to the growing body of knowledge of transfusion medicine, Lee demonstrates that it is safe to give group O blood to patients of any blood group, and that blood from all groups can be given to group AB patients. The terms "universal donor" and "universal recipient" are coined.

1914 Long-term anticoagulants, among them sodium citrate, are developed, allowing longer preservation of blood.

1915 At Mt. Sinai Hospital in New York, Richard Lewisohn uses sodium citrate as an anticoagulant to transform the transfusion procedure from direct to indirect. In addition, R. Weil demonstrates the feasibility of refrigerated storage of such anticoagulated blood. Although this is a great advance in transfusion medicine, it takes 10 years for sodium citrate use to be accepted.

1916 Francis Rous and J.R. Turner introduce a citrate-glucose solution that permits storage of blood for several days after collection. Allowing for blood to be stored in containers for later transfusion aids the transition from the vein-to-vein method to direct transfusion. This discovery also allows for the establishment of the first blood depot by the British during World War I. Oswald Robertson is credited as the creator of the blood depots.

1914-1918 Two major advances take place out of need to relieve the pressure caused by trying to save lives during the Great War. The first is the discovery that blood could be prevented from clotting once it's removed from the body by mixing it with sodium citrate. And like most things, they also discover that blood can last a bit longer if it's put in a fridge.

1921 The British Red Cross members all decide to give blood at Kings College Hospital, London, and so the first voluntary blood service is born.

1932 The first blood bank is established in a Leningrad hospital.

1936 The Americans open the world's first blood bank at Cook County Hospital, Chicago.

1937 Bernard Fantus, director of therapeutics at the Cook County Hospital in Chicago, establishes the first hospital blood bank. In creating a hospital laboratory that can preserve and store donor blood, Fantus originates the term "blood bank." Within a few years, hospital and community blood banks begin to be established across the United States. Some of the earliest are in San Francisco, New York, Miami and Cincinnati.

1939 After the outbreak of war, things really kick off with four large civilian centres being set up near London and at an Army centre near Bristol.

1939/40 The Rh blood group system is discovered by Karl Landsteiner, Alex Wiener, Philip Levine and R.E. Stetson and is soon recognized as the cause of the majority of transfusion reactions. Identification of the Rh factor takes its place next to ABO as one of the most important breakthroughs in the field of blood banking. Britain open their first blood bank in Ipswich. While the war rages, obviously there is a greater need for blood so the emergency medical services and the Army set up eight regional transfusion centres. And thousands of civilians do their bit for the country by donating, saving the lives of many servicemen and civilians.

Edwin Cohn, a professor of biological chemistry at Harvard Medical School, develops cold ethanol fractionation, the process of breaking down plasma into components and products. Albumin, a protein with powerful osmotic properties, plus gamma globulin and fibrinogen are isolated and become available for clinical use. The efficacy of albumin in transfusion is demonstrated by John Elliott.

1943 The introduction by J.F. Loutit and Patrick L. Mollison of acid citrate dextrose (ACD) solution, which reduces the volume of anticoagulant, permits transfusions of greater volumes of blood and permits longer term storage.

1945 Coombs, Mourant and Race describe the use of antihuman globulin (later known as the “Coombs Test”) to identify “incomplete” antibodies.

1946 The National Blood Service is launched (under the the name Blood Transfusion Service).

1950 Audrey Smith reports the use of glycerol cryoprotectant for freezing red blood cells.

1950 In one of the single most influential technical developments in blood banking, Carl Walter and W.P. Murphy, Jr., introduce the plastic bag for blood collection. Replacing breakable glass bottles with durable plastic bags allows for the evolution of a collection system capable of safe and easy preparation of multiple blood components from a single unit of whole blood. Development of the refrigerated centrifuge in 1953 further expedites blood component therapy.

1948 The National Health Service is set up in England and North Wales (yes, the National Blood Service came first). But right from the start, a strong partnership is established between the two.

Mid-1950s In response to the heightened demand created by open heart surgery and advances in trauma care patients, blood use enters its most explosive growth period.

1959 Max Perutz of Cambridge University deciphers the molecular structure of hemoglobin, the molecule that transports oxygen and gives red blood cells their color.

1960 A. Solomon and J.L. Fahey report the first therapeutic plasmapheresis procedure.

1961 The role of platelet concentrates in reducing mortality from hemorrhage in cancer patients is recognized.

1975 While everyone is busy wearing flares and having bad hair, the National Blood Service quietly gets on with replacing glass bottles with plastic blood bags, and therefore allowing a much wider use of blood components.

1986 HIV testing is introduced.

1991 And just as importantly, testing for hepatitis C is introduced.

#14 Lazarus Long

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Posted 29 October 2002 - 01:00 PM

I have chosen to end this time-line short of today's advances for a reason. I think we are in a watershed period of Histology and of Hematology. We are about to apply methods and awareness predicated upon whole new areas of knowledge and technology such as Genetics and Nanotechnology to this quintessential aspect of life's substance. Blood is the fluid that much of what modern medicine is about to accomplish will be both barrier to, and medium for success.

Also I decided to not edit my previous incorrect post for a reason. It is sometimes better to honestly admit a mistake then to blithely try to erase it. I would rather learn from my mistakes and go forward then to fall prey to the idea that it is ever better in science (or in society for that matter) to believe a cover up is better.

I am not a physician but I want the ideas I am trying to convey to have a weight greater then the credentials I bear. To do that I must be honor bound to truth above all else. It is the "message", not the messenger that is of ultimate importance.

#15 Lazarus Long

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Posted 23 December 2002 - 02:38 PM

If one lives long enough, the veracity of all prediction can be tested, and the accuracy of all prophecy measured. Or maybe it is also a consequence of socio-technological acceleration as a response to the demands of rational proposals but here is an announced breakthrough that can be republished in a half dozen areas of this forum, and one that heps establish a measure our predictive ability.

Human Kidneys Grown in Mice

Scientists Grow Human Kidneys in Mice
2 hours, 3 minutes ago
Monday, Dec 23, 2002

LONDON (Reuters) - Israeli scientists said on Monday they had successfully grown human kidneys in mice, in a breakthrough that might one day help save thousands of patients waiting for transplants.

Tens of thousands of patients worldwide, including 50,000 in the U.S. alone, need a new kidney. Many die before a suitable donor is found. The researchers, led by Dr. Yair Reisner of the Weizmann Institute of Science, said they had transplanted stem cells from human and pig fetuses into mice.

The kidneys grew into functional mouse-sized organs, filtering the blood and producing urine, they reported in Nature Medicine journal.

Stem cells are special "mother" cells that can develop into the organs and tissues of the body. The researchers used those rich in precursor kidney cells, those most likely to form kidney tissue.

But knowing when best to transplant was a challenge.

They said they had used stem cells at different stages of development and found that those which produced the healthiest kidneys came from human fetuses between seven and eight weeks old, and pig fetuses four weeks old.

Donating organs from one species to another, a field known as xenotransplantation, has long been held back because the human immune system often recognizes the animal organ as foreign and rejects it.

In this case there was no dangerous immune reaction, possibly because the transplanted cells had not yet developed their own identity badge.

Even if this problem is overcome, scientists will still want reassurance that there is no risk of unknown animal viruses being passed to humans.

Kidney specialists believe that although the latest research is encouraging, many more trials must be done before there is any prospect of applying it in human medicine.

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#16 Lazarus Long

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Posted 23 December 2002 - 02:44 PM

BBC Version

Monday, 23 December, 2002, 00:01 GMT
Human kidneys grown in mice

Posted Image The mice were injected with pig and human cells

Doctors have managed to make cells taken from human foetuses grow into fully-functional kidneys in a mouse.
The technique could offer a more practical way of helping patients who need organ transplants.

Thousands in the UK alone are on the waiting list for a new kidney.

Even if one is found, the patient will have to take anti-rejection drugs forever.

However, just a small number of specially-selected cells taken from the foetus and transplanted into a mouse were able to carry on developing and create an entire organ with all its different parts.

No human source

And while the age of the foetal cells required means it would be impossible to establish a supply from a human source, researchers achieved the same effect with pig embryo cells.

This might allow replacement organs to grow from pig tissue without some of the normal problems this might create, such as rejection of the new organ by the human immune system.

The advance, by doctors at the Weizmann Institute of Science in Israel, was reported in the latest edition of Nature Medicine.

The technique works because cells were taken from the aborted foetuses aged between seven and eight weeks, and from pig foetuses which are only four weeks old.

Early cell

At that time, the foetus is just preparing to develop its kidneys, and a type of cell called a "kidney precursor".

This is a stem cell, a master cell that has the ability to divide and become all the different types of cell required to form a fully-grown kidney.

Both porcine (pig) and human versions of these cells were taken and transplanted into mice.

Both types developed into perfect organs at an appropriate size for a mouse.

They produced urine and were supplied with blood by vessels from the host.

In addition, there was no dangerous immune response to the new organs - scientists believe because the cells were taken early in foetal development, cells which would normally trigger the immune system were not present.

The researchers involved said that a possible treatment might be developed within the next few years.

However, while there is growing support for the use of pig organs in transplantation, some experts still believe there is a tiny risk that previously unknown viruses could pass into humans and cause illness.

Professor Robin Weiss, from University College London, said the potential threat from "retroviruses" - which are actually coded into the genetic makeup of every pig cell, remained even if organs from adult pigs were not used.

He said: "It's exactly the same, no better or worse.

"Retroviruses are not a huge risk, but it presents a problem, and it's better to be wise before the event."




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