Thorac Cardiovasc Surg 2024; 72(S 01): S1-S68
DOI: 10.1055/s-0044-1780584
Sunday, 18 February
This work was supported by the Werner Otto Foundation and the German Heart Foundation.

Pharmacological KLF-2 Upregulation Prevents Endocardial Fibroelastosis in an Animal Model of Congenital Heart Disease

Authors

  • G. Gierlinger

    1   Department of Cardiac Surgery, Boston Children's Hospital, Harvard Medical School, Boston, United States
    2   Division of Pediatric and Congenital Heart Surgery, Kepler University Hospital, Linz, Austria
    3   Johannes Kepler University, Medical Faculty, Linz, Austria

  • D. Diaz-Gil

    1   Department of Cardiac Surgery, Boston Children's Hospital, Harvard Medical School, Boston, United States
    4   Pediatric Cardiology, University Medical Center Hamburg-Eppendorf, Hamburg, Deutschland

  • N. Silva-Gomez

    1   Department of Cardiac Surgery, Boston Children's Hospital, Harvard Medical School, Boston, United States

  • L. Rech

    1   Department of Cardiac Surgery, Boston Children's Hospital, Harvard Medical School, Boston, United States
    5   Division of Cardiology, Medical University of Graz, University Heart Center Graz, Graz, Austria

  • S. Koutsogiannaki

    6   Department of Anesthesiology, Boston Children's Hospital, Harvard Medical School, Boston, United States

  • R. Kozlik-Feldmann

    4   Pediatric Cardiology, University Medical Center Hamburg-Eppendorf, Hamburg, Deutschland

  • C.M. Wolf

    7   Department of Congenital Heart Disease and Pediatric Cardiology, Technical University of Munich, Munich, Deutschland

  • R. Mair

    2   Division of Pediatric and Congenital Heart Surgery, Kepler University Hospital, Linz, Austria

  • S. Emani

    1   Department of Cardiac Surgery, Boston Children's Hospital, Harvard Medical School, Boston, United States

  • P.J. Del Nido

    1   Department of Cardiac Surgery, Boston Children's Hospital, Harvard Medical School, Boston, United States

  • I. Friehs

    1   Department of Cardiac Surgery, Boston Children's Hospital, Harvard Medical School, Boston, United States
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Background: Endocardial fibroelastosis (EFE) is a distinctive form of early left ventricular (LV) fibrosis frequently observed in congenital heart defects such as hypoplastic left heart syndrome (HLHS) and critical aortic stenosis. EFE is regulated through the TGF-β pathway via endothelial-to-mesenchymal transition (EndMT) in the endocardium. EndMT also plays a major role in atherosclerosis, and the pleiotropic effects of lipophilic statins are mediated via upregulation of the zing finger protein Krüppel-like factor 2 (KLF2), which protects the vascular endothelium through inhibition of the TGF-β pathway. The aim of this study was to inhibit EndMT of the endocardium through upregulation of KLF2 with the lipophilic statin atorvastatin.

Methods: Healthy endocardial endothelial cells were isolated from lambs, stimulated with recombinant TGF-β and exposed to flow stagnation with and without atorvastatin (0.5 µmol/L) treatment for 72 hours. Heterotopic neonatal rat heart transplantation was performed to simulate flow stagnation within the neonatal LV and thereby stimulate EndMT. Atorvastatin (3 mg/kg/day) was injected intraperitoneally (n = 7) for 14 days and untreated/vehicle treated rats served as a control (n = 8). Gene expressions of EndMT regulation (SMAD2, SNAI2) and KLF2 were analyzed by qRT-PCR, and immunohistochemical staining was performed to determine EndMT. EFE thickness was measured in histological Masson’s trichrome stained tissue from neonatal donor hearts.

Results: Atorvastatin-treated isolated endocardial endothelial cells showed reduced EndMT (downregulation of SMAD2, p < 0.05) and increased KLF2 expression compared to untreated controls (p < 0.001). In transplanted neonatal rat hearts, the mean LV EFE diameter was 201 μm ± 41 μm in the control group compared to 72 μm ±13 μm in the atorvastatin treated group (p < 0.001). EndMT was decreased (downregulation of SNAI2, p < 0.05), and KLF2 upregulated (p < 0.05) in atorvastatin treated neonatal rat heart tissue. Immunohistochemical staining of EndMT markers showed less myocardial infiltration of EFE in atorvastatin treated rat hearts.

Conclusion: The transition of healthy endocardial endothelial cells to EFE was prevented through upregulation of KLF-2 with atorvastatin in our in-vitro cell experiments as well as in the in-vivo neonatal rat heart transplantation model. This could potentially pave the way for an innovative treatment approach for patients experiencing LV restriction due to EFE.



Publication History

Article published online:
13 February 2024

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