Brain transplant

Not to be confused with Head transplant.

A human brain in a jar.

A brain transplant or whole-body transplant is a procedure in which the brain of one organism is transplanted into the body of another organism. It is a procedure distinct from head transplantation, which involves transferring the entire head to a new body, as opposed to the brain only. Theoretically, a person with complete organ failure could be given a new and functional body while keeping their own personality, memories, and consciousness through such a procedure. Neurosurgeon Robert J. White has grafted the head of a monkey onto the headless body of another monkey. EEG readings showed the brain was later functioning normally. Initially, it was thought to prove that the brain was an immunologically privileged organ, as the host's immune system did not attack it at first,[1] but immunorejection caused the monkey to die after nine days.[2]

Existing challenges

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Cross section view of nerve tissue.

One of the most significant barriers to the procedure is the inability of nerve tissue to heal properly; scarred nerve tissue does not transmit signals well, which is why spinal cord injuries devastate muscle function and sensation.

Alternatively, a brain–computer interface can be used connecting the subject to their own body. A study[3] using a monkey as a subject shows that it is possible to directly use commands from the brain, bypass the spinal cord and enable hand function. An advantage is that this interface can be adjusted after the surgical interventions are done where nerves can not be reconnected without surgery.

Also, for the procedure to be practical, the age of the donated body must be close to that of the recipient brain: an adult brain cannot fit into a skull that has not reached its full growth, which occurs at age 9–12 years.

When organs are transplanted, aggressive transplant rejection by the host's immune system can occur. Because immune cells of the CNS contribute to the maintenance of neurogenesis and spatial learning abilities in adulthood, the brain has been hypothesized to be an immunologically privileged (unrejectable) organ.[4][5][6] However, immunorejection of a functional transplanted brain has been reported in monkeys.[7]

Partial brain transplant

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In 1982, Dr. Dorothy T. Krieger, chief of endocrinology at Mount Sinai Medical Center in New York City, achieved success with a partial brain transplant in mice.[8]

In 1998, a team of surgeons from the University of Pittsburgh Medical Center attempted to transplant a group of brain cells to Alma Cerasini, who had suffered a severe stroke that caused the loss of mobility in her right limbs as well as had limited speech. The team hoped that the cells would correct the listed damage. She died later on.[9]

See also

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References

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  1. ^ Adams, Cecil (20 December 2013). "What Would Happen in a Brain Transplant?". Washington City Paper.
  2. ^ McCrone, John. "head transplants". Archived from the original on 28 February 2015. Retrieved 20 January 2015.
  3. ^ Ethier, C.; Oby, E. R.; Bauman, M. J.; Miller, L. E. (April 2012). "Restoration of grasp following paralysis through brain-controlled stimulation of muscles" (PDF). Nature. 485 (7398): 368–371. Bibcode:2012Natur.485..368E. doi:10.1038/nature10987. ISSN 0028-0836. PMC 3358575. PMID 22522928. Archived from the original (PDF) on 21 July 2013.
  4. ^ Ziv, Yaniv; Ron, Noga; Butovsky, Oleg; et al. (2006). "Immune cells contribute to the maintenance of neurogenesis and spatial learning abilities in adulthood". Nature Neuroscience. 9 (2): 268–275. doi:10.1038/nn1629. ISSN 1097-6256. PMID 16415867. S2CID 205430936.
  5. ^ Jacobson, Lou (August 1997). "A Mind is a Terrible Thing to Waste". Lingua Franca.
  6. ^ Mike Darwin: But What Will The Neighbors Think? A Discourse On The History And Rationale Of Neurosuspension. Cryonics, October 1988.
  7. ^ McCrone, John (December 2003). "Monkey Business". Lancet Neurology. 2 (12): 772. doi:10.1016/S1474-4422(03)00596-9. PMID 14636785. S2CID 5254407. Archived from the original on February 28, 2015. Retrieved January 20, 2015. (As reproduced at author's personal webpage)
  8. ^ "Transplant Success Reported With Part of a Mouse's Brain". The New York Times. Associated Press. 18 June 1982. Retrieved 20 July 2010.
  9. ^ Vedantam, Shankar (2 July 1998). "Artificial Brain Cells Implanted In-Patient The Procedure Is The First of Its Kind. Doctors Hope Eventually To Treat Brain Disorders This Way". The Philadelphia Inquirer. Archived from the original on 18 April 2016. Retrieved 29 May 2013.
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