Therapeutic potential of human iPS cell-derived cardiac tissue in an ischemic model with unloaded condition mimicking left ventricular assist device

OBJECTIVE

This study aimed to explore the therapeutic potential of hiPSC-derived cardiac tissues (HiCTs) in the emerging approach of "Bridge to recovery (BTR)" for severe heart failure with ventricular assist devices (VADs). We utilized a rat model of heterotopic heart transplantation (HTx) to mimic VAD support and heart unloading.

METHODS

HiCTs were created by inserting gelatin hydrogel microspheres between cell sheets made from hiPSC-derived cardiovascular cells. Male athymic nude rats underwent myocardial infarction (MI) and were divided into the following groups: MI (loaded, untreated control), MI+HTx (unloaded, untreated control), MI+HTx+HiCT (unloaded, treated), and MI+HiCT (loaded, treated). HiCTs were placed on the epicardium of the heart in treated groups. We evaluated HiCT engraftment, fibrosis, neovascularization using histological analysis.

RESULTS

After four weeks, HiCTs successfully engrafted in five out of six rats in the MI+HTx+HiCT group (83.3%). The engrafted HiCT area was greater under unloaded conditions (MI+HTx+HiCT) than loaded conditions (MI+HiCT) (P<0.05). MI+HTx+HiCT had a significantly smaller infarct area compared to MI and MI+HTx. The MI+HTx+MiCT group exhibited higher vascular density in the border zone than MI and MI+HTx. HiCT treatment suppressed cardiomyocyte atrophy due to LV unloading (P=0.001). The protein level of MuRF1, an atrophy-related ubiquitin ligase, was lower in the MI+HTx+HiCT group than MI+HTx (P=0.036). However, HiCT treatment did not significantly improve LV systolic function in unloaded hearts.

CONCLUSIONS

Transplanting HiCTs into ischemic hearts under unloaded conditions promoted engraftment, neovascularization, attenuated infarct remodeling, and suppressed myocyte atrophy. These results suggest that HiCT treatment could contribute to future advancements in BTR. (250 words).

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Successful surgical treatment of intravascular ultrasonography catheter entrapment

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