Putrescine has been found useful to treat atherosclerosis

Putrescine could be very useful to combat one of the most common conditions affecting the cardiovascular system, namely atherosclerosis. Putrescine is that compound whose unmistakable smell is one of the most “bad” present in nature. We are talking about the smell emanating from rotting meat.

According to a new study conducted by researchers at the Irving Medical Center at Columbia University, it is possible to use this substance for the benefit of humans. The researchers assumed that the removal of dead cells, a process that is called “efferocytosis” and which is one of the main functions of the body, is usually compromised when the condition of atherosclerosis exists. This compromise then leads to the accumulation of plaques and aggravation of the condition itself.

By analyzing human macrophages and dying cells in the laboratory, researchers discovered the role of putrescine. While macrophages extract arginine and additional amino acids from the dead cells they assimilate, they also convert arginine into putrescine. Arginine then activates the Rac1 protein that signals macrophages to “eat” dead cells.

Researchers then carried out experiments on mice with atherosclerosis and found that the more severe mice had low stocks of putrescine because they lacked the key enzyme (arginase 1) to produce putrescine itself. By making rodents drink water with putrescine, the macrophages resumed working and the accumulation of plaques decreased.

These results open up new avenues for the possible use of putrescine even in human atherosclerotic patients or in other conditions with cranial inflammation, including Alzheimer’s disease. The study is available on Cell Metabolism.

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The Pacific Northwest Temperature ranged widely between 800,000 and 750,000 years ago

Surface water temperature in the Northwest Pacific Ocean fluctuated widely between 800,000 and 750,000 years ago according to a new study conducted by a team of researchers from the National Institute of Polar Research (NIPR) and Ibaraki University. The researchers analyzed the oxygen isotopes of some fossils of foraminiferous, amoeboid marine microorganisms found on the island of Honshu, Japan.

According to the researchers, these changes were due to the discharge in this marine area of massive amounts of water derived from ice melting in the North Atlantic. This study could also be useful to understand climate change in the same area in the future.

According to the researchers, in fact, in order to assess the anthropogenic effects on ongoing climate change, it is necessary to make comparisons with the climates and environmental conditions that have occurred in the past, changes that naturally had no anthropogenic causes.

The study, published in the Earth and Planetary Science Letters, describes the methods researchers used to collect and then analyze fossils of four species of foraminifera taken from the MIS layer19. This sediment layer refers to a hot interglacial period of 790,000 to 760,000 years ago.

Based on previous studies that had shown that low oxygen isotope values of foraminiferous fossils correspond to higher water temperatures, the researchers came to the conclusion that there must be, in addition to the glacial-interglacial cycle that repeats on time scales of tens of thousands of years, other cycles related to water temperature.

Specifically, this temperature would oscillate in an extreme way, of about 7°, every few thousand years. In addition, analyses seem to show that these changes have occurred due to the outflow of water from icebergs in the North Atlantic.

“Surprisingly, the changes in the North Atlantic have caused dramatic fluctuations in water temperature in the remote Pacific Northwest,” says Yuki Haneda, NIPR scientist and one of the authors of the study. “We believe that the fossils collected from the outcrop are a tracer that integrates the data reported from deep water sediments. The composite section of Chiba is the global boundary stratification section and point (GSSP) of the lower-middle Pleistocene boundary and offers a remarkable understanding of global environmental changes during that period. We want to improve our understanding of climate change during MIS19 to predict future climate change more accurately.”

Magnetic microrobots in the body to regenerate knee cartilage

Microrobots that, once grafted into the body, can regenerate the cartilage of the knee, at least in rabbits: this is the result achieved by some researchers from various Chinese institutes and one Korean who published their study in Science Advances.

One of the most common disorders of older people is cartilage degeneration, especially in the hips and knees. The most common treatment to date is to replace the knee or hip joint with artificial devices. This is quite a serious problem considering also that the populations in the world are getting older and older and therefore problems like these, related to cartilage, are more and more widespread.

Previous research, however, had already shown that mesenchymal stem cells, those present in bone marrow and fat, can be transformed into cartilage cells in the laboratory and can also be used to repair damaged cartilage. However, the challenge has been to graft these special cells into the body and keep them in the right position to attach them to the surrounding tissue and trigger cartilage regrowth.

It seems that Chinese and Korean researchers have succeeded in just that: they created tiny hollow spheres with holes made from a polymer called PLGA or poly(lactic-co-glycolic acid). These small spheres were then sprinkled with a mixture of ferumoxytol (iron oxide) and chitosan (a sugar). The same balls were then filled with mesenchymal stem cells previously grown in the laboratory.

Finally, the same balls were inserted into the knees of various rabbits with damaged cartilage. Magnets from outside the body were used to hold them in place. After three weeks the researchers noticed that the cartilage of the rabbits’ knees showed signs of rejuvenation and at the same time the balls were emptying.

Now the researchers want to test animals with knees more similar to those of humans to see if such a technique can be used on people.

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