Clin Res Cardiol (2022). https://doi.org/10.1007/s00392-022-02002-5

Reduced hypertrophic growth of plasma-treated cardiomyocytes in vitro predicts poor outcome in patients with cardiac transthyretin amyloidosis

S. Hein1, J. Furkel2, M. Knoll3, F. aus dem Siepen1, U. Hegenbart4, S. Schönland4, H. A. Katus1, A. V. Kristen5, N. Frey1, M. Konstandin1

1Klinik für Innere Med. III, Kardiologie, Angiologie u. Pneumologie, Universitätsklinikum Heidelberg, Heidelberg; 2Universitätsklinikum Heidelberg, Heidelberg; 3Abteilung für Radioonkologie und Strahlentherapie, Universitätsklinikum Heidelberg, Heidelberg; 4Medizinische Klinik V, Universitätsklinikum Heidelberg, Heidelberg; 5Kardiovaskuläres Zentrum Darmstadt, Darmstadt;

AIM: In ATTR amyloidosis misfolded protein is deposited in the myocardium. However, direct functional effects of the misfolded or mutant transthyretin on cardiomyocytes hypertrophic growth as well as its impact on clinical outcome are not yet fully understood. METHODS: Human plasma samples were collected from patients presenting in our tertial referral center for amyloidosis and stored at -80° degrees until experiments were performed. Human plasma was added to NRCM cell culture with and without additional phenylephrine (PE) stimulation. After 48 hours of incubation, cells were fixed and immunohistochemically stained for Desmin and nuclear DNA. Using fully automated high throughput microscopy immunofluorescence pictures were acquired from the cellular body and nuclei. Using Cell Profiler software and CMORE, a custom written R package, cell size analysis was conducted automatically. RESULTS: In vitro cardiomyocyte growth response was evaluated in 105 individuals. 89 suffered from mutant or wildtype transthyretin amyloidosis. 16 were healthy controls. To integrate untreated and PE-stimulated condition in one metric the "Hypertrophic Index (HI)" was defined as increase in cell size upon PE stimulation normalized to cell size under the unstimulated condition. Its prognostic value was assessed for multiple endpoints (HTX: death/heart transplantation; DMP: cardiac decompensation; MACE: combined) using Cox proportional hazard models. Cells treated with plasma from healthy controls and hereditary transthyretin amyloidosis with polyneuropathy showed an increase in HI, whereas stimulation after treatment with hereditary cardiac amyloidosis or wild-type transthyretin patient plasma showed a significantly attenuated response. In univariate analyses HI was associated with HTX (hazard ratio (HR) high vs low: 0.12 [0.02-0.58], p = 0.004), DMP: (HR 0.26 [0.11-0.62], p = 0.003) and MACE (HR 0.24 [0.11-0.55], p < 0.001). Its prognostic value was independent of established risk factors, cardiac TroponinT or N-terminal prohormone brain natriuretic peptide (NTproBNP) in the multivariate analysis. Conclusion: Reduced HI is an independent risk predictor of poor outcome in ATTR patients. Underlying mechanisms need to be addressed in further studies.

https://dgk.org/kongress_programme/jt2022/aP812.html