Nanosheets for blood cleansing
To protect against sepsis, an "artificial spleen" was created
Copper news based on Nature News: Artificial spleen cleans up bloodBioengineering specialists from Harvard University have developed a so–called "artificial spleen" - a high-tech extracorporeal device designed to quickly and effectively purify the blood from any pathogenic microorganisms and prevent the development of sepsis.
A description of the device (Joo H Kang et al., An extracorporeal blood-cleansing device for sepsis therapy) was published on September 14 in the journal Nature Medicine.
Sepsis (sometimes called blood poisoning) is a potentially life–threatening condition caused by an excessive immune response to the causative agent of infection, which entails a systemic inflammatory reaction, multi-organ dysfunction, septic shock and death. As a rule, since it takes too long to identify a specific pathogen that caused a septic reaction, broad-spectrum antibiotics are used as a therapy method, which reduces the effectiveness of treatment and leads to the development of antibiotic resistance of bacteria.
In search of a solution to this problem, a group led by cell biologist and bioengineer Donald Ingber took the spleen as a sample – an organ that acts, among other things, as a filter that cleanses the blood from various foreign agents. The extracorporeal device they created uses nano-sized magnetic beads coated with a modified version of mannose-binding lectin (MBL), a protein that plays a crucial role in the human innate immunity system. MBL recognizes and binds mannose monosaccharide molecules on the surface of more than 90 types of pathogenic microorganisms (bacteria, viruses, fungi) and their waste products. It is the endotoxins they release into the blood that trigger an excessive immune response leading to septic shock.
By analogy with the dialysis procedure, the patient's blood enters the "artificial spleen" – a device no larger than a deck of cards, where it passes through a layer of MBL-coated magnetic beads that "collect" almost all pathogens and endotoxins present in it. Then, with the help of a magnet, the blood is released from the beads and, in an already purified state, returns to the patient's body.
Artificial spleen and magnetic nanoparticles plastered with E. coli (blue) and S. aureus (yellow) bacteria.
Pictures from the press release of the Wyss Institute Blood-cleansing biospleen device developed for sepsis therapy – VM.
Testing of the device on rats infected with E.coli or Staphylococcus aureus bacteria demonstrated its high efficiency – within an hour, the "artificial spleen" removed more than 90 percent of bacteria and their waste products from the blood of animals. Five hours after infection, 89 percent of rats whose blood was filtered through the device survived, compared with only 14 percent of those who were deprived of such therapy. At the same time, filtration allowed to reduce the level of inflammatory reaction in the lungs and other organs, which protected the animals from sepsis.
The effectiveness of the "artificial spleen" was also tested on human blood – about five liters were "driven" through the device, which is the approximate volume of blood circulating in the body of an adult. The blood was infected with a mixture of bacteria, fungi and endotoxins and was pumped through the device at a rate of about a liter per hour. Within five hours, the "artificial spleen" almost completely cleared the blood of pathogens. Such a level of efficiency of the device, Ingber believes, is quite sufficient to control infection – what the "artificial spleen" will not remove, antibiotics and the immune system itself will "finish". Ingber also noted that the principle of operation of the device allows it to be used in the treatment of such serious viral diseases as, for example, HIV and Ebola, in which survival depends on a qualitative reduction in the level of viral load in the blood.
Currently, Ingber's group is testing an "artificial spleen" on pigs whose sepsis development mechanisms are similar to human ones. Experts expect the start of clinical trials of the device in the next two years.
Portal "Eternal youth" http://vechnayamolodost.ru16.09.2014