[ad_1]
They are the scavengers of the abyss and death.
Hakehills are slimy city dwellers who live on carcbades of Dead Sea creatures and thrive in deep waters where oxygen is hard to find. In fact, their hearts can continue to beat for 36 hours without oxygen, making the hagfish a champion among the anoxic tolerant fish.
In contrast, a human heart is permanently damaged after only a few minutes without oxygen.
Research conducted by the University of Guelph has revealed clues as to how hagfish make their hearts beat, even after running out of oxygen. By unveiling the mysteries of the hagfish heart, this work could provide new insights into how to protect the human heart when oxygen delivery is impaired, for example during a heart attack.
"We want to understand how these fish hearts can work so long without oxygen, as this could lead to innovative strategies for preserving human heart tissue during a myocardial infarction or a heart transplant," said Professor Todd Gillis, who led this study alongside a recent MSc. Lauren Gatrell graduate.
Gillis is a professor in the Department of Integrative Biology and a founding member of the UG's Center for Cardiovascular Investigations.
Gatrell and Gillis sought to understand what fed hagfish hearts when they lacked oxygen.
"We wanted to know what metabolic fuels were used and how they were using them, since the heart of most vertebrates lacks cellular energy when oxygen is eliminated. That 's what causes them. tissue damage. "
Posted in Journal of Comparative Physiology, the study tested two potential sources of fuel: glucose and glycerol.
Earlier, Gillis had discovered that at the beginning of an anoxic exposure, hagfish hearts used glycogen as energy, a form of glucose stored in the muscles. But these glycogen stores are not enough to maintain the heart rate during continued exposure to anoxia, and it was unclear what fuel was taking over once the glycogen was depleted.
Gatrell exposed isolated myxin hearts at 12 hours of anoxia or normoxia, during which time she fed hearts in saline containing glucose, glycerol or any fuel source, while measuring cardiac contraction.
During these experiments, the hearts continued to pump, even without oxygen.
"If you treated a mammalian heart in the same way, it would stop beating quickly and be permanently damaged, and you would have to continue to stimulate it with a slight electric shock just to make it beat." But the hagfish's heart continues to Generating enough electrical power to keep working, "said Gillis." They're kind of like zombie hearts, they'll literally keep beating – it's pretty amazing to see. "
Experiments revealed that providing glycerol to hearts during anoxia markedly increased heart contraction, even more so when hearts were fed with glucose, which is usually the fuel that muscles prefer.
"We are always trying to understand what it means," said Gillis. "These results raise many other exciting questions – is there any benefit to using glycerol – is it an ancestral anomaly or the outcome of evolution if glycerol stimulates them?"
Gillis suspects glycerol to be delivered to the liver by the liver.
"We think it flows through the fish in their blood," he said. "We found very high levels of glycerol in the liver, where it would be produced and then transported to the tissues."
He was fascinated by the fact that hagfish hearts react so strongly to glycerol and admitted to finding it a little strange.
"But almost everything about hagfish is weird – it's just another weird thing that they can do – now we need to know how and why they do it."
[ad_2]
Source link
