Reviving Cells After a Heart Attack
Researchers have unraveled potential mechanisms behind the healing power of extracellular vesicles and demonstrated their capacity to not only revive cells after a heart attack but keep cells functioning while deprived of oxygen during a heart attack. The researchers demonstrated this functionality in human tissue using a heart-on-a-chip with embedded sensors that continuously tracked the contractions of the tissue.
- Extracellular Vesicles (EVs) are nanometer-sized messengers that travel between cells known as intercellular communication.
- EVs are a promising tool for the next generation of therapies for everything from autoimmune and neurodegenerative disease to cancer and tissue injury.
- EVs derived from stem cells have already been shown to help heart cells recover after a heart attack, but exactly how they help and whether the beneficial effect is specific to EVs derived from stem cells has remained a mystery.
Researchers from Harvard School of Engineering and Applied sciences have unraveled a potential mechanism that demonstrated the potential mechanism behind the healing power of EVs and demonstrated their capacity to not only revive cells after a heart attack but keep cells functioning while deprived of oxygen during a heart attack.
How was this discovered? Researchers used a heart-on-a-chip with embedded sensors that continuously tracked the contractions of the tissue.
The team tested the effect of Endothelial-derived EV’s (EEVs) on human heart tissue using the heart-on-a-chip model. Organ-on-chip platforms mimic the structure and function of native tissue and allow researchers to observe, in real-time, the effects of injuries and treatments in human tissue.
Reperfusion injury mechanism
The absence of oxygen and nutrients from blood during the ischemic period creates a condition in which the restoration of circulation results in inflammation and oxidative damage through the induction of oxidative stress rather than (or along with) restoration of normal function. The ischemic tissue produces more reactive oxygen species but less nitric oxide following reperfusion and the imbalance results in an inflammatory response.
Findings in the research study
- The researchers simulated a myocardial infarction and reoxygenation on chips that were infused with EEVs and those that were not.
- They found that in tissues treated with EEVs, the cardiomyocytes could better adapt to stress conditions and sustain a higher workload.
- The researchers induced injury by three hours of oxygen restrictions followed by 90 minutes of reoxygenation and then measured the fraction of dead cells and the contractile force of the tissue.
- The heart tissue treated with EEVs had half as many dead cells and had a contractile force four times higher than the untreated tissue after injury.
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