New in vivo priming strategy to train stem cells can enhance cardiac repair effectiveness

March 27, 2020

Human stem cells have been regarded as one of the promising cell sources for cardiac regeneration therapy. But their clinical use is hampered due to the poor performance after transplantation into failing hearts. Recently a stem cell biologist from City University of Hong Kong (CityU), together with his collaborators, has developed a novel strategy, called in vivo priming, to "train" the stem cells to stay strong after implantation to the damaged heart via the 3D-printed bandage-like patch. The positive results of the study show that an in vivo priming strategy can be an effective means to enhance cardiac repair.

Dr Ban Kiwon, Assistant Professor of CityU's Department of Biomedical Sciences, collaborated with cardiologist and experts in 3D printing from South Korea in achieving this breakthrough. Their findings were published in the latest issue of the scientific journal Science Advances, titled "In vivo priming of human mesenchymal stem cells with hepatocyte growth factor-engineered mesenchymal stem cells promotes therapeutic potential for cardiac repair".

Harsh environment in failing hearts hinders stem cell survival

One of the proposed approaches to treat myocardial infarction, commonly known as heart attack, with regeneration therapy is to inject the human stem cells directly into the failing hearts. In particular, human mesenchymal stem cells (hMSCs) have been considered as a competitive agent for clinical uses for their proven safety and significant paracrine effects supporting new blood vessel formation and inhibiting cell death. However, "the clinical trial results are disappointing as the micro-environment of a failing heart is very harsh for the injected hMSCs to stay alive," said Dr Ban.

Therefore researchers have been exploring ways to increase the survival rate of hMSCs in failing hearts. "Priming, or called preconditioning, is a common strategy to empower the cells. The cells are educated through certain stimulations, and when they are relocated to tough environments, they are much stronger against bad condition and they will know how to react because of their previous experiences," explained Dr Ban.

Conventionally, priming is performed in vitro (outside a living organism) before the cells are transplanted into the heart. "But the effects of priming done in this way usually last for two or three days only. To extend the duration of the priming effect, I have come up with an idea of 'in vivo priming', which means the hMSCs are primed directly on the failing hearts," said Dr Ban.

Novel strategy: in vivo priming of hMSCs

To prove the concept, the research team loaded two types of MSCs into a tailor-made 3D-printed patch, namely the human bone marrow-derived MSCs, and the genetically engineered MSCs which have human hepatocyte growth factor protein. Hepatocyte growth factor (HGF) is involved in multiple biological activities, such as cell survival, blood vessel formation, anti-fibrotic activities, and important in adult organ regeneration and wound healing.

The patch, like a bandage, was then implanted on the top of the infarct area of the myocardial-infarction-induced heart of rats. "The genetically engineered MSCs can continuously secret human HGF protein to prime the hMSCs within the patch and make them 'stronger'," said Dr Ban.

Instead of directly injecting the genetically engineered cells into the heart, he added that encapsulating the cells in the patch for putting on the surface of the heart can help prevent mutation or other undesirable outcomes. And the patch is fabricated by 3D-printing of pig heart-derived extracellular matrix hydrogel, simulating the cardiac tissue-specific micro-environment.

It was found that the primed hMSCs had a higher survival rate compared with unprimed ones in the patches attached to the failing hearts. Those empowered hMSCs released greater amounts of paracrine factors beneficial for repairing damaged cardiac muscle tissues and regenerating vasculatures.

"We found that the primed cells can survive even after 8 weeks in the patch after implantation to the heart. Also, there is a significant improvement in cardiac function as well as vessel regeneration comparing to the unprimed cells," said Dr Ban.

Great improvement of the priming effect

"Our team is the very first to achieve priming in hearts in vivo. But more importantly, by showing that in vivo priming of hMSCs can enhance the therapeutic potential for cardiac repair, we hope our study can bring significant implications for related stem cell therapy in future," concluded Dr Ban. It took the team over two years to achieve these remarkable results. The team will explore the possibility of conducting the experiments on bigger animals and even clinical trials, as well as modifying the structure of the patch.
-end-
Dr Ban, Dr Jang Jinah from Pohang University of Science and Technology, as well as Professor Park Hun-Jun from The Catholic University of Korea are the leading authors of the paper. Mr Lee Sunghun, a PhD student from Department of Biomedical Sciences at CityU also participated in this research.

The study was supported by CityU, Hong Kong Research Grants Council, National Research Foundation of Korea, Ministry of Education as well as the Ministry of Science and ICT in South Korea.

City University of Hong Kong

Related Stem Cells Articles from Brightsurf:

SUTD researchers create heart cells from stem cells using 3D printing
SUTD researchers 3D printed a micro-scaled physical device to demonstrate a new level of control in the directed differentiation of stem cells, enhancing the production of cardiomyocytes.

More selective elimination of leukemia stem cells and blood stem cells
Hematopoietic stem cells from a healthy donor can help patients suffering from acute leukemia.

Computer simulations visualize how DNA is recognized to convert cells into stem cells
Researchers of the Hubrecht Institute (KNAW - The Netherlands) and the Max Planck Institute in Münster (Germany) have revealed how an essential protein helps to activate genomic DNA during the conversion of regular adult human cells into stem cells.

First events in stem cells becoming specialized cells needed for organ development
Cell biologists at the University of Toronto shed light on the very first step stem cells go through to turn into the specialized cells that make up organs.

Surprising research result: All immature cells can develop into stem cells
New sensational study conducted at the University of Copenhagen disproves traditional knowledge of stem cell development.

The development of brain stem cells into new nerve cells and why this can lead to cancer
Stem cells are true Jacks-of-all-trades of our bodies, as they can turn into the many different cell types of all organs.

Healthy blood stem cells have as many DNA mutations as leukemic cells
Researchers from the Princess Máxima Center for Pediatric Oncology have shown that the number of mutations in healthy and leukemic blood stem cells does not differ.

New method grows brain cells from stem cells quickly and efficiently
Researchers at Lund University in Sweden have developed a faster method to generate functional brain cells, called astrocytes, from embryonic stem cells.

NUS researchers confine mature cells to turn them into stem cells
Recent research led by Professor G.V. Shivashankar of the Mechanobiology Institute at the National University of Singapore and the FIRC Institute of Molecular Oncology in Italy, has revealed that mature cells can be reprogrammed into re-deployable stem cells without direct genetic modification -- by confining them to a defined geometric space for an extended period of time.

Researchers develop a new method for turning skin cells into pluripotent stem cells
Researchers at the University of Helsinki, Finland, and Karolinska Institutet, Sweden, have for the first time succeeded in converting human skin cells into pluripotent stem cells by activating the cell's own genes.

Read More: Stem Cells News and Stem Cells Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.