Hydrogel will help in the treatment of heart attack
A sticky, protein-enriched hydrogel developed by Johns Hopkins University researchers promotes the preservation of transplanted stem cells in rat heart tissue and the restoration of its metabolism, which improves cardiac function after a simulated myocardial infarction.
According to the head of the study, Associate Professor M.Roselle Abraham, the experiments were based on the fact that, despite the huge potential demonstrated by stem cells in restoring organs after damage, their introduction into the tissue of the damaged heart does not bring the expected result due to the fact that only a few of them remain at the injection site. The reason for this lies in the contractions of the heart muscle, pushing the injected cells into the lungs along with the blood flow before they have time to integrate into the heart wall.
In addition, when cells are moved from the culture vial to the solution for injection into the body, their metabolism slows down. This leads to the death of cells within a few hours, that is, before they have the opportunity to attach to the tissue.
The researchers tried to increase the number of cells lingering in the heart muscle by administering large doses (several million cells), but an hour after administration, only 10-20% of the injected population remained in the tissues. And within 24 hours after administration, due to a difficult metabolism, most of these cells also died.
In search of solutions to these numerous problems, researchers have developed a hydrogel that includes serum, a protein–rich component of blood containing everything necessary for cell survival, and hyaluronic acid, a substance contained in the heart tissue and part of the extracellular matrix surrounding cells and supporting their viability. This composition performs the function of an artificial niche of stem cells: it encapsulates them, providing nutrition and rapid recovery of metabolism.
Experiments in Petri dishes showed that both adult and embryonic stem cells encapsulated in the new material not only survived at a level close to 100%, but also demonstrated active vital activity and even began to proliferate. They also, compared with the control culture of cells not encapsulated in gel, produced significantly more growth factors involved in the restoration of cardiac tissue.
When a combination of gel + stem cells was injected into the heart of living rats, the preservation of cells in the tissue after an hour was approximately 73%, whereas this indicator for cells injected in solution reached only 12%. Over the next 7 days, the number of cells injected into the heart in standard solution continued to decrease, while the population of gel-encapsulated cells increased.
Moreover, in a rat model of myocardial infarction, four weeks after the introduction of cells encapsulated in hydrogel, an increase in the efficiency of the pumping function of the left ventricle of the heart was recorded by 15%, compared with 8% for control group animals that were injected with a solution containing cells. Even the introduction of a cell-free hydrogel significantly improved the functioning of the heart and increased the number of blood vessels in the area of myocardial infarction.
The authors hope that over time the approach they have developed will find application in the cellular therapy of myocardial infarction in humans.
Article by Angel T. Chana et al. Hyaluronic acid-serum hydrogels rapidly restore metabolism of encapsulated stem cells and promote engraftment is published in Biomaterials.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on Johns Hopkins University: Sticky Gel Helps Stem Cells Heal Rat Hearts.
Portal "Eternal youth" http://vechnayamolodost.ru
28.09.2015