Clin Res Cardiol (2025). DOI 10.1007/s00392-025-02737-x
1Universitätsmedizin Göttingen Institut für Pharmakologie und Toxikologie Göttingen, Deutschland; 2Universitätsmedizin Göttingen Herzzentrum, Klinik für Kardiologie und Pneumologie Göttingen, Deutschland
Background:
With a limited potential to recover from injury, following a myocardial infarction the heart is subjected to ischemia, reperfusion, fibrosis, ventricular remodeling, all of which lead to adverse post-infarction remodeling that impairs normal heart function. We hypothesized that pre-conditioning using simulated fasting approaches together with temporary and localized DLK1 expression by CRISPR/Cas9 gene activation may confer cardioprotection in engineered human myocardium (EHM).
With a limited potential to recover from injury, following a myocardial infarction the heart is subjected to ischemia, reperfusion, fibrosis, ventricular remodeling, all of which lead to adverse post-infarction remodeling that impairs normal heart function. We hypothesized that pre-conditioning using simulated fasting approaches together with temporary and localized DLK1 expression by CRISPR/Cas9 gene activation may confer cardioprotection in engineered human myocardium (EHM).
Methods and Results:
We utilized the EHM model together with a reoxygenation injury model. EHM were subjected to 1% oxygen conditions for 48 hrs, followed by 24 hrs of reoxygenation at 21% oxygen. We screened a panel of drugs for their potential to activate AMPK as a method of promoting cellular fasting responses. Drug effect and their effective concentration ranges were established using an AMPK biosensor. Prior to injury EHM were pre-conditioned using fasting media or drugs aimed at regulating activity of AMPK to simulate fasting. Live tracking of EHM function was achieved through a 48-well imaging platform utilizing flexible poles and measuring pole deflection over time. Upregulation of DLK1 preserved EHM function during hypoxia (-18% ± 14% [n=10]), with simulated fasting achieving similar results (-21% ± 8% [n=10]). In a DLK1-KO EHM model the protective effect is lost during hypoxia (-75% ± 25% [n=10]). However, with simulated fasting pre-conditioning long-term recovery potential is increased in both DLK1a (ctrl: 14% ± 69% [n=6], treatment: 224% ± 261% [n=7]), and DLK1-KO models (ctrl: 77% ± 51% [n=5], treatment: 67% ± 48% [n=5]).
Conclusion:
The EHM model is susceptible to reoxygenation injury with potential for metabolic drug screening applications. Cellular fasting and localized upregulation of DLK1 may provide a combinatorial effect to protect from hypoxia-reoxygenation injury.