The problems of transplanting animal organs

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The problems of transplanting animal organs into
humans
Jenny Kukielski
Jeong Ryul Lee, M.D. Pediatric Cardiac
Surgery Seoul National University Hospital
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The end of the night shift Organ transplantation
today and tomorrow

• The future
• Donor center
• Regular working hour
• 200 procedures a day
• daily-base available
• The present
• Telephone at 2 AM
• A car-accident donor
• 1-2 hour-drive for harvest
• Get back to hospital at 7 AM
• Heart transplantation
• Continue regular cases

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Animal attraction (1) Supply and demand in the
world of organ transplantation

• The heart patient
• 14 year old previously healthy boy
• Virus induced cardiomyopathy
• ICU care for 3 weeks
• Boys heart failure getting worse
• Listed in heart transplantation
• Transfer to LVAD available center
• Risk during transportation
• The harsh statistics
• 63000 waiting for organ in USA
• Listing for organ every 18 minutes
• Average waiting over 1 year

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Animal attraction(2) Supply and demand in the
world of organ transplantation

• Closing the donor-recipient gap
• Raising the possibilities of organ donation
• Presumed consent donation unless objection
• Draw attention from public with newsworthy
  people
• Donor rate 10-30/ million
• Donor rate of hospital death 4
• Living donors
• Increasing unrelated living donor
• Organ brokers the ethical dilemma
• Arrange dealing organs from poverty-stricken man
• Rewarded gifting

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Animal attraction(3) Supply and demand in the
world of organ transplantation

• The real extent of the problem
• Legal and cultural barrier
• The borderline candidates
• Limited potential of artificial organs

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From Icarus to the first transplant(1) Mans
first attempts to bridge the species gap

• Daedalus and Icarus in mythology feather into
  arm
• 1921 Paris, Sexual rejuvenation by xenografting
  (baboon)
• Reemtsma Tongue into cheek
• 1628 Italy, Blood transfusion from sheeps to
  humans
• 1682 Russia, Dog skull into human skull
• 1880 Chicago, Dr.Lees Lamb, Pedicled skin
  graft
• 1800s The fashion for frogs, Skin graft
• 1907 Alexis Carrel, Vessel anastomosis

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From Icarus to the first transplant(2) Mans
first attempts to bridge the species gap

• Transplantation of kidney
• 1902, Emerich Ullman, Vienna Pig kidney to
  human arm vessel
• 1905, Princeteau, French Rabbit kidney slices
  to child kidney
• 1906, Matheu Jaboulay, Frenchpig and goat
  kidney to human arm
• 1910, Ernest Unger monkey kidney to human
  /stillbirth human kidney to baboon
• 1963, Keith Reemtsma, Louisiana,13 chimpanzee
  kidney into human
• 1964, Tom Starzl, Colorado, 6 baboon kidney into
  human(17-60d)

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From Icarus to the first transplant(3) Mans
first attempts to bridge the species gap

• Transplantation of animal heart
• 1964, James Hardy, U Mississippi chimpanzee
  heart to human , size mismatch
• 1968, Denton Cooley, Donald Ross, Texas and
  London sheep and pig heart to human
• 1977, Christian Barnard, Cape Town chimpanzee
  and baboon heart as auxiliaries
• 1984, Leonard Bailey, Loma Linda Baby Fae (20d)
• 1992, Poland, Pig heart to human(24h)
• 1996, India (0d)

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From Icarus to the first transplant(4) Mans
first attempts to bridge the species gap

• Transplantation of animal livers
• 1992, Tom Starzl Pittsburgh, baboon liver to
  human(70d with vigorous immunosuppression)
• Extracorporeal liver perfusion, USA, South Africa

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All animals are equal, but some are more equal
than others The choice of donor

• Candidate number 1 The great apes
• The closeness of phylogenetic relationships
  (98)
• Time-consuming and expensive source of organs
• Poor public consensus
• Their scarcity problem

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All animals are equal, but some are more equal
than others The choice of donor

• Candidate number 2 The baboon
• Non-human primate
• Sufficient number
• Closed breeding possible
• Possible virus transmission
• Size mismatch (40kg adult)
• One offspring
• Sexual maturation by 3-5 years
• 9 years for adult sized growth
• Consistency in different environment (thick
  bile)
• Risk of infection AIDS, SV,
• Poor public compliance

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All animals are equal, but some are more equal
than others The choice of donor

• Candidate number 3 The pig(1)
• Less public controversy
• Sufficient number
• Reproductive maturity within 6 months
• Sows mating capable every 3 weeks
• Pregnancy less than 4 months (3m3w3d)
• Easy and cheap to maintain
• Rapid growth (1year to adult size)
• Miniature pigs (Pigmees) well matching in size
• Similar anatomy and physiology to human
• Both pigs and humans omnivorous
• Extensively studied animal

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All animals are equal, but some are more equal
than others The choice of donor

• Candidate number 3 The pig(2)
• Potential for genetic engineering
• Less worrisome zoonosis
• Pig disease and defects ( 0.004 cancer )
• Tissue typing in pig ( Class IIClass I)
• Weak blood group antigen expression
• To be in the center of the study ( humanized/
  disease free)

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Zero tolerance The rejection of animal organs

• The power of nature
• The most powerful immunological reaction
• Safety tools to defend against microorganisms
• A reflex reaction to foreign threat
• The human bodys oldest and strongest natural
  survival mechanism

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Zero tolerance The rejection of animal organs

• Transplantation between closely related animals
  
• Antibody- or AntibodyCell mediated
• Large dose immunosuppression months
• Inevitable risk of infection, drug related
  complication
• Inevitable chronic rejection

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Zero tolerance The rejection of animal organs

• Transplantation between distantly related
  animals
• The first barrier Hyperacute rejection
• Antibody already circulating in large numbers
• The nature of anti pig antibodies
• Surgeons and scientist from Oklahoma(Eugen Koren
  from Croatia, 1991) Alberta(Heather Good)
• Galactose
• Uri Galili, Biological detective Only human,
  great ape, old world monkey capable of Ab
  production
• The remaining barriers peeling an onion
• NK, macrophage
• Cellular rejection

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The Spoonful of Sugar Prevention of rejection

• Overcoming the first hurdle
• Preventing hyperacute rejection(1)
• Perfusion of recipient serum into first pig
  organ
• Refining the technique Plasma exchange with
  immunosuppressionsplenectomy
• Being more specific depleting anti-Gal
  antibodies
• Accommodating the transplanted organs after
  2-3wk of depletion of Abs
• The pioneering work Guy Alexandre (Belgian)
• Replace serum with saline or innocuous solution
• Splenectomy immunosuppression
• ABO incompatible kidney transplantation

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The Spoonful of Sugar Prevention of rejection

• Overcoming the first barrier
• Preventing hyperacute rejection(2)
• Egidio Romanos new concepts
• Antibody inhibition by injectable sugar
• To remove anti-A antibody for A type blood
• The scientist as a guinea pig
• Therapy at 1 million a day 90/mg of sugar
  (Chembiomed Ltd.)
• Gal-filled cartridge less expensive
• Anti-idiotype antibody antibodies against
  antibodies
• Mouse anti- anti-pig antibodies
• Depletion or inhibition of complement
• CVF rapid complement consumption
• Soluble complement factor 1 (Fred Sanfilippo
  from Johns Hopkins)

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The Spoonful of Sugar Prevention of rejection

• Overcoming the second barrier
• Preventing Delayed antibody-mediated rejection
• Antibody-mediated without complement
• Fritz Bach from Beth-Israel, Jeff Platt from
  Duke
• The right immunosuppressive combinations
  maintenance of low anti-pig antibodies

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The Spoonful of Sugar Prevention of rejection

• Overcoming the third barrier
• Preventing acute cellular rejection
• Antirejection drugs
• Azathioprine, British, Sir Roy Calne (1960s)
  killing dividing T-cell
• Corticosteroid suppress T-cell
• ATG/ALS Rabbit antihuman-T-cell antibodies, Sir
  Michael Woodruff(British), Anthony Monaco and
  Paul Russell(Harvard surgeon)
• Cyclosporine (late 1970s) inhibition of T-cell
  function
• Jean Borel, Swiss immunologist, Sandoz, now
  Norvatis)
• Sir Roy Calne, David White, British experiment
• OKT3 Killing T-cell
• Ben Cosimi, MGH
• Mouse anti-T-cell antibodies
• Tacrolimus, Tom Starzl competing cyclosporine
• Mycophenolate mofetil replace azathioprine

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The Spoonful of Sugar Prevention of rejection

• Overcoming the fourth barrier
• Preventing Chronic rejection
• At present no effective tx for chronic rejection
• Second transplantation

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The Humanized Pig Manipulating the genes of the
donor

• Genetic engineering Giving the pig human
  genes(1)
• Present technique
• Extremely inefficient
• 10 out of 100 embryos-1-2 transgenic
• Possible weak expression
• Present technique
• Superovulation
• Mating within 24 h
• Random needling of genes
• 25 embryos in 1 sow
• 1 fetus live birth
• sometimes with no expression
• Breeding

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The Humanized Pig Manipulating the genes of the
donor

• Genetic engineering Giving the pig human
  genes(1)
• Gal negative pigs
• Gal Knocking out Knocking out the sugar
• Oklahoma, Melbourne, Austin
• not available in pig
• GT KO in pig
• GAL KO in mice (Tony dApice from Melbourne
  Australia)
• Human serum still destroy the mouse organ
• Anti-non-Gal Ab
• Competing with Gal
• A gene for fucosyl transferase
• A gene for a-Galactosidase

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The Humanized Pig Manipulating the genes of the
donor

• Genetic engineering Giving the pig human
  genes(2)
• Protection against human complement
• hDAF
• MCP
• CD59

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The Humanized Pig Manipulating the genes of the
donor

• Cloning, the new technology
• Keith Campbell, Scottish biotechnology company,
  PPL Therapeutics
• Nuclear transfer technique into egg fetal or
  embryo fibroblast
• Single generation multiple off-springs

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The Immunological Holy Grail Tolerance

• The limitations of present day 50 failure at
  10y
• The concept of tolerance
• Accept foreign without any long-term drug
  therapy
• Donor specific
• Not affecting host immune system
• No drug-related cancer development
• Free of acute or chronic rejection

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The Immunological Holy Grail Tolerance

• In search of tolerance (1)
• South African experience
• Johannes Myburgh, surgeon
• Total lymphoid irradiation(thymusLN) on
  recipient baboon? Kidney transplantation from
  donor baboon
• Clinically not relevant
• The NIH-Harvard experience
• David Sachs successful induction of tolerance
  in rodents
• Ben Cosimi Bone marrow irradiation T-cell
  cytotoxic drugsthymus irradiation insufficient
• Plus BM transplantation from the same donor
  chimeric immune system (mixed chimerism)? kidney
  transplantation from the same donor
• Controllable infection

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The Immunological Holy Grail Tolerance

• In search of tolerance (2)
• Can we learn to tolerate pigs?
• B-cell toleranceabsent antibody production
• Anti-pig antibodies from B-cell/Plasma cell Ab
  depletion required, irradiation resistant,
• Gal-KO
• Molecular incompatibility
• Pig BM cell not proliferate well in baboon
  stroma
• Pig specific growth factor required

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The Immunological Holy Grail Tolerance

• Spontaneous unresponsiveness
• No rejection after cessation of
  immunosuppressive drugs
• Molecular chimerism (new concept)
• Pig genes for major antigen cloned, GT gene
• BM cell from recipient baboon aspirated
• Retroviral vector mediated pig gene transfection
  into baboon cell
• These cell back into baboon BM after whole body
  irradiation
• Pig kidney transplantation into baboon
• Induction of chimerism before birth
• All developing human fetus injected with pig
  cells
• For future pig organ transplantation

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The discordant concert Will the transplanted
organ work?

• Living out of ones elements
• Physiological biochemical difference
• Specific pig organs
• Electrolytes
• The effect of evolution
• Cholesterol
• Clot or bleed
• Growth hormone
• Aging of tissues
• Erythropoietin and red blood cells
• A new science Xenoincompatibility

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The Hottest zone The fear of an AIDS-like epidemic

• The ever present fear
• Transplanting microbes
• The risk of cross-species infection
• Making the donor pig safe
• Monitoring for infectious organism
• Mad pig disease
• PERV
• Human factor
• Non-compliant patient

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Guinea pig The selection of the first patient

• Laboratory to hospital
• Are we ready for a clinical transplantation?
• A need to be identified
• An appropriate group of patient to be identified
• A sufficient experimental advances
• An ethical appropriateness
• Who are the most likely guinea pig?
• Those who have nothing to lose
• Back-up therapy available group
• Is the technology ready ?
• When will it happen?