Mutations in thyroid hormone receptor α1 (TRα1) cause Resistance to Thyroid Hormone α (RTHα), a disorder characterized by hypothyroidism in TRα1-expressing tissues including the heart. Surprisingly, we report that treatment of RTHα patients with thyroxine to overcome tissue hormone resistance does not elevate their heart rate. Cardiac telemetry in male, TRα1 mutant, mice indicates that such persistent bradycardia is caused by an intrinsic cardiac defect and not due to altered autonomic control. Transcriptomic analyses show preserved, thyroid hormone (T3)-dependent upregulation of pacemaker channels (Hcn2, Hcn4), but irreversibly reduced expression of several ion channel genes controlling heart rate. Exposure of TRα1 mutant male mice to higher maternal T3 concentrations in utero, restores altered expression and DNA methylation of ion channels, including Ryr2. Our findings indicate that target genes other than Hcn2 and Hcn4 mediate T3-induced tachycardia and suggest that treatment of RTHα patients with thyroxine in high dosage without concomitant tachycardia, is possible.

Direct Link: https://doi.org/10.1038/s41467-023-38960-1

Journal: Nature Communications. 2023 Jun 7;14(1):3312

Keywords: Heart Rate, resistance to Thyroid Hormone α, tachycardia, thyroid, thyroxine,

Applications: Heart Rate,

CamNtech Reference: AH23013

Back to Search Results

UK & International customers

CamNtech Ltd.
Manor Farm
Fenstanton
Cambridgeshire
PE28 9JD, UK

US customers

CamNtech Inc.
630 Boerne Stage Airfield,
Boerne,
Texas 78006,
USA

Copyright

© 2022 CamNtech Ltd and CamNtech Inc

Company information

Registered in England No. 2221302
VAT No: GB486 3019 34


Privacy Policy