title: Thyroid hormone: relevance to xenotransplantation.
abstract: It has been well documented that the level of serum/plasma free triiodothyronine (fT3) falls rapidly following brain death or during certain surgical procedures, for example, heart surgery carried out on cardiopulmonary bypass. The level in patients following cardiopulmonary bypass usually recovers within 2 days.
  
  
  
  We have measured serum fT3 in healthy naïve baboons (n = 31), healthy naïve monkeys (n = 5), and after pig-to-baboon heterotopic heart xenotransplantation (xenoTx) (Group 1, n = 9), orthotopic liver xenoTx (Group 2, n = 10), artery patch xenoTx (Group 3, n = 9), and in monkey-to-monkey heterotopic heart alloTx (Group 4, n = 5).
  
  
  
  The mean level of fT3 in healthy naïve baboons was 3.1 ± 0.9 pg/ml and in healthy naïve monkeys was 2.6 ± 0.3 pg/ml. Following pig heart, liver, and artery patch xenoTx and monkey heart alloTx, there was an immediate rapid fall in fT3 level. Recovery of fT3 was more rapid in Groups 3 and 4 than in Groups 1 and 2. In Group 1, within 4 days fT3 had recovered, but only to the lower limit of normal range, where it remained throughout follow-up (for up to 42 days). In Group 2, no recovery was seen during the 7 days of follow-up. In immunosuppressed baboons with pig patch grafts that received IL-6R blockade (n = 2), the fT3 tended to rise higher than in those that received no IL-6R blockade (n = 6).
  
  
  
  Following operative procedures, there is a dramatic fall in serum fT3 levels. The persistent low level of fT3 after pig heart and liver xenoTx may be associated with a continuing inflammatory state. We suggest that consideration should be given to the replacement of T3 therapy to maintain normal fT3 levels, particularly in nonhuman primates undergoing orthotopic pig heart or liver xenoTx.
authors.affiliation: Thomas E Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Hayato
authors.initials: H
authors.lastname: Iwase
authors.affiliation: Thomas E Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Burcin
authors.initials: B
authors.lastname: Ekser
authors.affiliation: Thomas E Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Hara
authors.affiliation: Thomas E Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Mohamed B
authors.initials: MB
authors.lastname: Ezzelarab
authors.affiliation: Thomas E Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Cassandra
authors.initials: C
authors.lastname: Long
authors.affiliation: Thomas E Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Angus W
authors.initials: AW
authors.lastname: Thomson
authors.affiliation: Revivicor, Blacksburg, VA, USA.
authors.forename: David
authors.initials: D
authors.lastname: Ayares
authors.affiliation: Thomas E Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: David K C
authors.initials: DK
authors.lastname: Cooper
mesh_terms: D000818:Animals; D001158:Arteries / Q000378:metabolism / Q000637:transplantation; D016027:Heart Transplantation; D064593:Heterografts / Q000378:metabolism*; D016031:Liver Transplantation; D010215:Papio; D013552:Swine; D013963:Thyroid Hormones / Q000378:metabolism*; D014183:Transplantation, Heterologous / Q000379:methods; D014284:Triiodothyronine / Q000097:blood
chemical_list: D013963:Thyroid Hormones; D014284:Triiodothyronine
keywords: euthyroid sick syndrome; genetically engineered pigs; inflammation; nonhuman primates; thyroid hormone; xenotransplantation