PhD Scientific Days 2022

Clinical Medicine V. (Poster discussion will take place in the Aula during the Coffee Break)

Relevance of Deiodinase Enzymes in Heart Transplant – Preliminary Study

Text of the abstract

Introduction: The hypothalamic-pituitary-thyroid (HPT) axis plays a huge role in regulation of metabolism throughout the neuroendocrine system. The low triiodothyronine (T3) syndrome appears in several critical conditions that require intensive care, such as heart transplant (HTx) which is the gold standard therapeutic intervention for patients with end-stage chronic heart failure. Low T3 syndrome is hallmarked by reduced serum thyroid hormone levels and altered deiodinase enzymes activities.
Aims: Current study aimed to investigate the connection between the HPT axis and adverse outcomes after HTx.
Method: This prospective, single center study was approved by the IRB (65/2017). Patients who underwent heart transplant at the Heart and Vascular Centre of Semmelweis University between 2012 and 2020 were enrolled in current research. Demographic and perioperative laboratory parameters, thyroid disorders and adverse outcomes were recorded in our database. Deiodinase 2 (DIO2) and deiodinase 3 (DIO3) enzymes expressions were measured with TaqMan qPCR and were normalized to hypoxanthine phosphoribosyl transferase (HPRT). 30 ng of cDNA was used in each qPCR reaction. Descriptive statistics, Spearman’s correlation and Mann-Whitney U test were applied for the statistical analysis.
Results: The final analysis was performed on 294 patients, of whom 77 were female (26.2%) and 217 were male (73.8%). The median age of donors was 54 years (IQR 25-75: 45-59), while the median follow-up was 1223 days (IQR 25-75: 399-1990). Prior to surgery, 53 patients (18.0%) had subclinical thyroid hormone levels, of whom 37 (12.6%) were on thyroid hormone replacement. Patients required postoperative mechanical circulation support (n: 50; 17.0%), underwent rejection (n: 47; 16.0%), and reoperation (n: 34; 11.6%) had significantly lower DIO2 and DIO3 activities (respectively p: 0.016; 0.001; 0.044). However, DIO2 expression was significantly higher in patients with postoperative acute kidney injury (n: 75; 25.5%) (p: 0.033).
Conclusion: Our results emphasize the importance of thyroid hormone function during the perioperative period of heart transplant as DIO2 and DIO3 enzymes expressions may predict the occurrence of some complications after heart transplant.
Funding: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.