Controlled Epicardial Angiogenic Factor Stimulation for Improved Cardiac Regeneration upon Infarction via a Novel Biologic Patch

Introduction: Epicardial cells (EPDC) have the potential to fully regenerate infarcted myocardium for example by angiogenic factor secretion. However, that distinctive mechanism is only present in post-natal mice or lower vertebrates. Mammals such as humans cannot regenerate the heart upon infarction in that way event though the mechanism because the mechanism too attenuated. Seeking for alternative treatments to whole organ transplantation in end-stage cardiac failure we designed a novel epicardial patch composed of cell-free amniotic membrane (DeAM) scaffold coated with human cardiac extracellular matrix hydrogel (gECM) and colonized with activated EPDC. Then we characterized their hypoxia-sensitive cardio-protective properties.

Material & Methods: Intact human LV myocardium was received from non-ischemic heart failure patients undergoing transplantation and decellularized, pulverized and processed towards hydrogel by pepsin digestion. Mass spectrometry identified important ECM protein preservation. DeAM was dry-coated with gECM (DeAM + E) and characterized by electron microscopy and mechanical behavior. EPDCs, isolated from heart auricles, were forced to undergo EMT by TGF-β stimulation and cell compatibility with DeAM + E (Adhesion, Necrosis, Proliferation) was examined. Their proangiogenic secretion profile and cardioprotective effects were determined by antibody array, scratch assay, and HL-1 coculture in ischemia.

Results: The gECM forms additional solid biological nano scaffold onto DeAM + E and mechanical stability of DeAM + E allows epicardially suturing. Colonized EPDCs showed higher adhesion capacity on DeAM + E, LDH-release was significantly decreased on both DeAM and DeAM + E, whereas BrdU-incorporation was increased only on DeAM + E. EPDC-conditioned medium exhibited clear angiogenetic cytokine secretion. Scratch assay exerts fastened wound closure within 24 hours. HL-1 cells showed an increased viability in ischemic environments as demonstrated by LDH-release, Resazurin-conversion, and BrdU incorporation.

Conclusions: Hydrogel processing does not cause a critical loss in ECM protein composition and improves cardiac cell culturing. Highly sensitive to hypoxic stimuli EPDC represent a striking effector cell line to design an epicardial patch. In conclusion, using hcECM coated amniotic membrane combined with EPDC, we succeeded to design a novel patient specific regenerative epicardial patch hybrid system.