Authors
Kostelnik, C. J., Piekarska, M. L., Sreedhar, S., Lin, C.-Y., Shah, A., Gaweda, B., Goodyke, A. J., Xu, Y., Balachandran, K., Parast, L., Bersi, M. R., Timek, T. A., Rausch, M. K.
Abstract
Background: Moderate to severe tricuspid regurgitation (TR) affects approximately 1.6 million Americans, yet more than 90% of patients with significant TR remain untreated. Women exhibit higher TR prevalence and more rapid disease progression than men, but the valve-intrinsic mechanisms underlying these sex disparities remain unclear. We hypothesized that sex and circulating testosterone influence tricuspid leaflet remodeling during right-sided pressure overload. Methods: Female, castrated male (C-Male), and non-castrated male (NC-Male) adult Dorset sheep (n = 45) underwent pulmonary artery banding (PAB) and were followed for 13 {+/-} 1.5 weeks. Tricuspid leaflets were evaluated using morphometry, 3D profilometry, biaxial mechanical testing, histology, and bulk RNA sequencing. Sex-stratified differential gene expression was performed, and pathway enrichment of key biological processes were compared between sexes. Results: PAB produced a uniform hemodynamic stimulus and equivalent moderate-to-severe TR across sex groups. Despite similar TR burden, leaflet remodeling diverged substantially by sex and castration status. C-Males developed the broadest remodeling phenotype, characterized by diffuse multi-leaflet growth, thickening, increased nuclei count, and low-strain stiffening. Females demonstrated more restricted leaflet and region-specific structural and cellular changes, along with circumferential low-strain stiffening. NC-Males exhibited preferential septal remodeling characterized by growth, thickening, increased nuclei count, and radial high-strain stiffening. Transcriptomic analysis revealed that females upregulated a focused matricellular remodeling program enriched for extracellular space organization (67 DEGs; FDR=0.025), whereas C-Males activated coordinated extracellular matrix and apoptosis-regulatory programs (388 DEGs; FDR=0.009). In contrast, NC-Males exhibited broad transcriptional response (406 DEGs) without significant pathway enrichment. Conclusions: Tricuspid leaflet maladaptation during pressure overload is sex-dependent and testosterone-sensitive, involving distinct structural, mechanical, and transcriptional remodeling programs. These findings identify sex and testosterone status as previously under-recognized modulators of tricuspid valve remodeling and may help explain clinical sex disparities in TR progression.
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bioRxiv
The authors list and abstract were imported from bioRxiv on 07 Aug 2026.
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