Thyroid hormone: relevance to xenotransplantation

Area of Science:

• Endocrinology
• Transplantation Immunology
• Surgical Research

Background:

• Serum/plasma free triiodothyronine (fT3) levels decrease after brain death and certain surgeries like cardiopulmonary bypass.
• fT3 levels typically normalize within two days post-cardiopulmonary bypass.

Purpose of the Study:

• To measure serum fT3 levels in nonhuman primates undergoing xenotransplantation and allogeneic transplantation.
• To investigate the impact of different xenotransplantation procedures on fT3 levels and recovery patterns.

Main Methods:

• Serum fT3 was measured in healthy baboons and monkeys.
• fT3 levels were monitored after pig-to-baboon heterotopic heart xenotransplantation (xenoTx), orthotopic liver xenoTx, artery patch xenoTx, and monkey-to-monkey heterotopic heart alloTx.

Main Results:

• All transplantation groups showed an immediate, rapid decline in fT3 levels.
• fT3 recovery was faster in artery patch xenoTx and heart alloTx groups compared to heart and liver xenoTx groups.
• fT3 levels remained low up to 42 days post-heterotopic heart xenoTx and showed no recovery within 7 days post-orthotopic liver xenoTx.

Conclusions:

• Operative procedures cause a significant drop in serum fT3.
• Persistent low fT3 after pig heart and liver xenoTx may be linked to inflammation.
• T3 therapy replacement should be considered to maintain normal fT3 levels in nonhuman primates undergoing specific xenotransplantations.