MEDICINE A new multipronged strategy rejuvenates scarred heart muscle and damaged vascular tissue following severe heart attacks, healing damage usually considered irreversible and requiring a heart transplant. Heart attacks occur when the heart’s blood supply is suddenly cut off, leading to permanent and irreversible damage to heart tissue, called a myocardial infarction. Heart transplants are sometimes the only treatment option available for people with severe myocardial infarction and advanced heart failure. But heart transplants are very risky, costly and subject to limited, suitable donors. Stem cell-based therapies have recently emerged as a promising therapeutic alternative. “Since both cardiac muscles and blood vessels are severely damaged following myocardial infarction, therapeutic strate-
gies should focus on the comprehensive repair of both at the same time. But so far strategies have only focused on one or the other,” says stem cell biologist Kiwon Ban at City University of Hong Kong. Ban collaborated with researchers in South Korea to develop a therapeutic approach using two major types of stem cells: human bone-marrow-derived mesenchymal stem cells (hMSCs) and cardiac muscle cells, or ‘cardiomyocytes’, derived from human induced pluripotent stem cells (hiPSC-CMs). hMSCs secrete proteins that promote blood vessel regeneration. hiPSC-CMs express cardiac-specific genes, structural proteins, ion channels and, more importantly, can spontaneously contract. hiPSC-CMs were injected directly into the heart wall of rats with myocardial infarction, while a patch loaded with
hMSCs was placed on top of the infarct area like a bandage. The approach led to significant improvement in cardiac function and enhanced blood vessel formation. The hMSC patch provided a micro-environment that enhanced vascular regeneration and also improved the retention of hiPSC-CMs, ultimately augmenting heart function and restoring the injured heart muscle. “We believe this novel dual approach can potentially provide translational and clinical benefits to the field of cardiac regeneration,” says Ban. “Based on the same principle, the protocol may also be utilized for repairing other organs with historically low regeneration potential, including the brain and pancreas.” The team is now working on follow-up studies in larger animal models.
DUAL STEM CELL THERAPY FOR REPAIRING FAILED HEARTS A new approach uses two types of stem cells to repair both heart muscle and blood vessels damaged during severe heart attacks.
Assistant Professor Kiwon Ban | E-mail: email@example.com Department of Biomedical Sciences City University of Hong Kong
Credit: Dr Ban Kiwon
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Immunostaining shows cardiac muscle cells derived from induced pluripotent stem cells in green; Troponin T, a protein found in heart muscle cells, in red; and cell nuclei in blue.