Blood carries oxygen and nutrients to the organs and cells of the body in mammals. But if the blood flow stops, these cells die quickly and infect the organs.
By slowing the death of organs and tissues removed from the body, time is gained for organ transplants. However, it can be difficult to protect all organ systems minutes after the heart stops pumping.
Current methods include a so-called extracorporeal membrane oxygenation (ECMO) system, which pumps blood through a machine that removes carbon dioxide while adding oxygen. While this serves the purpose of balancing the gases, every minute of delay allows damage to occur.
To solve the problem, a new system was presented to restore certain organ, cellular and molecular functions in dead pigs and preserve their tissue even if the treatment starts only one hour after the cardiac arrest.
The researchers adapted an existing technology called BrainEx, which has been shown to perform certain functions in the brains of isolated pigs hours after death.
Its new system, called OrganEx, also focuses on whole-body use in large mammals. OrganEx consists of: a device and a liquid.
The device is connected to the circulatory system. It creates a pulse-like heartbeat and oxygenates the fluid, similar to ECMO.
The device also includes several sensors for important circulatory characteristics such as metabolism, hemoglobin, pressure and flow.
An artificial fluid mixed with animal blood is pumped throughout the dead animal’s body in a 1:1 ratio. This fluid, unlike blood, is not made up of cells, but is designed to protect cells from damage and carry oxygen and medicines throughout the body.
The system was tested in pigs one hour after cardiac arrest, as well as in control groups where organ function was tested immediately after blood flow stopped and one hour and seven hours later. Tissue maintained at body temperature continues to process fuel and produce waste at a controlled rate.
One hundred pigs overall, including those used in system development, were used prior to published trials.
Researchers have discovered that OrganEx can maintain tissue integrity, reduce cell death, and stimulate certain molecular and cellular processes in vital organs such as the heart, brain, liver and kidneys.
OrganEx outperformed ECMO in all areas. Organs treated with the new system were less affected by bleeding or tissue inflammation, and the researchers observed gene expression patterns specific to repair processes within certain organs and types of tissue. cells.
The team also studied the structure of brain cells that often suffer from ischemia-related damage.
Brain cell counts decreased in all treatment groups, except for OrganEx and cells in the prefrontal cortex, where there was less damage in some parts of the brain, with cells returning to similar levels in the group without heat which is ischemia.
The main test for the success of the experiment is the restoration of organ function.
Brain function is measured using a continuous electroencephalogram. The scientists were determined to distinguish between the brain function they discovered and the electrical activity that could indicate a certain level of “life” (the main definition of death in clinical settings is brain death ).
While brain death persisted in the OrganEx group, cadavers showed some movement of the head and neck after injection of a contrast agent (used to help show more detail on imaging) into the carotid artery of the neck, which carries blood to the brain and head. This movement did not occur in live anesthetized animals or in the ECMO group.
“A conscious assessment is needed to explain why head and neck movements occurred after contrast injection only in the OrganEx group,” the researchers wrote.
They say that this shows that the output of the motor function is preserved, at least in the “cervical spinal cord or nerves”.
In the heart, some spontaneous activity was detected by ECG, and contractions of some left ventricular cells were detected in the OrganEx group, which was not detected in the ECMO group.
Other organs, such as the liver and kidneys, also showed some significant signs of improvement.
While this system is still a long way from being tested in humans, researchers believe OrganEx has tremendous potential for human organ transplantation. They hope this will improve the time it takes to preserve a transplantable organ; this could, for example, allow organs to be transported further afield to recipients in need.
“The results highlight the previously underestimated ability of the mammalian body to partially recover after blood flow is cut off, which may increase availability for organ transplants,” the researchers wrote.
However, the team said more work is needed “to fully understand the potential of OrganEx to aid in cellular recovery after death or cessation of circulation.”
The research was published in the journal Nature.
Source: Science Alert
Source: Arabic RT
