The COVID-19 messenger RNA (mRNA) vaccines[2] use lipid nanoparticles (tiny fat droplets) to deliver mRNA to the body’s cells. This mRNA tells cells to produce a dummy spike protein on their surface in order to imitate the protein on the virus that causes COVID-19. After that, the body creates an immune response by producing antibodies that may be employed if the individual becomes infected with the virus. The current research study employed a similar strategy for mRNA delivery. However, rather than eliciting an immune response, the researchers’ ultimate goal is to instruct the heart’s cells to repair themselves after a heart attack. This preliminary study was conducted to determine whether mRNA could be successfully delivered to the heart muscle in lipid nanoparticles. The researchers injected different formulations into the left ventricular wall of mouse hearts during open chest surgery under general anesthesia. Twenty-four hours after administration, the mice were sacrificed and the location of mRNA translation was examined. The researchers found that mRNA successfully reached the heart cells 24 hours after injection. However, despite injection into the heart, the highest levels of mRNA translation were found in cells of the liver and spleen. Study author Dr. Clara Labonia of the University Medical Center Utrecht, the Netherlands said: “High expression was expected in the liver, since it metabolizes the lipid nanoparticles. Nonetheless, it was encouraging to see that there was mRNA translation in the heart tissue which means that lipid nanoparticles could work as delivery systems for mRNA therapy.” She concluded: “The next step of this research is to test more formulations and choose the one which most efficiently targets the heart tissue. We will then assess whether delivery of mRNA to mice with ischaemic hearts (resembling a heart attack) has any therapeutic effect.” References and notes Funding: Funding was provided by the Dutch Heart Foundation (Dr. E. Dekker Senior Scientist grant, no. 2019T049).
