An artificial blood substitute from Transylvania

November 6, 2013 by John Hewitt report
An artificial blood substitute from Transylvania
Blood Substitutes. Credit: topnews

(Medical Xpress)—Researchers in Cluj-Napoca, Romania, have recently made some significant advances in developing artificial blood substitutes. Their formulation is based not on synthetic hemoglobins, but rather on hemerythrin protein extracted from marine worms. Led by Professor Radu Silanghi-Dumitrescu, from Babes-Bolyai University, the team has been testing their blood substitute in both mice and in cultured cells. Their initial results suggest that many of the adverse effects normally associated with either perfluorocarbon (PFC) or hemoglobin-based oxygen carrier (HBOC) substitutes can be eliminated, or at least minimized by using hemerythrin.

Human blood only has a shelf life of a few weeks. It also needs to be matched to the recipient's blood type, and while the risks of disease transmission can be minimized by testing, dangers still present if the donor has been recently infected. These facts of life have lead to huge efforts to build a better blood substitute, but so far results have not been encouraging.

What makes such a success, is a phenomenon known as cooperative binding. In a nutshell, as more oxygen binds to hemoglobin in the lungs, it becomes even easier for additional oxygen to bind. Similar affects also seem to occur in the opposite direction, for the unloading of oxygen, in tissues. Most hemerythrins are only about one-quarter as efficient as hemogobin, mainly because cooperative binding is not as common with them.

The problem with HBOCs is that one way or another, the hemoglobin they contain ends up escaping and causing serious damage to organs like the kidneys. HBOCs are usually only around 0.1 um in diameter, compared to 7um for (RBCs). While their small size allows them to penetrate and oxygenate the nooks and crannies of the body much better than RBCs, that same feature also leads to undesireable extravasation into tissue. The typical stop gap is to try to make the hemoglobin in HBOCs sturdier by cross-linking, polymerizing, or otherwise conjugating them to various polymers.

Researchers have found when these modified hemoglobins do get into tissues, they bind nitric oxide, which appears to have the result that the patient's blood pressure rises precipitously. HBOCs also cause cramping and abdominal pains which are likely the result of oxidative/nitrosative free-radical generation. The new tipple from Transylvania, which instead uses the hemerythrin, has much lower free-radical stress related reactivity than hemoglobin. The researchers looked at these effects both in human leukocytes and human umbilical cells. When compared with standard glutaraldehyde-polymerized bovine hemoglobin, their new substitute resulted in much healthier cultures.

The goal is not to develop a permanent replacement solution, but rather something that could be used to bridge a critical situation for the few hours or days it takes for the body's natural mercenaries to take over. Hemerythrin itself, despite its name, is not actually a heme molecule in the strict sense. It is virtually colorless when deoxygenated, but when bound with oxygen it turns a violet-pink. It is interesting to speculate if these new blood substitutes, or something similar to them, might one day afford new opportunity to image live brains in formerly unimagined detail.

Aside from scattering of light by lipids, heme in blood is also a major problem for optical imaging of the brain. Temporary use of substitutes may eventually permit new techniques similar to the Clarity methods to be used in live brains. Hemerythrin has many other unique properties which still need to be explored. Among its positive features, for example, are a much reduced affinity for carbon monoxide. While there will no doubt be many obstacles yet to be overcome before something like this could be put into widespread use, the results to date are very encouraging.

Explore further: Scientists use light to uncover the cause of sickle cell disease

More information: www.ias.ac.in/jbiosci/jun2011/215.pdf

Related Stories

Scientists use light to uncover the cause of sickle cell disease

November 5, 2013
In sickle cell disease, hemoglobin—the oxygen-carrying component of blood—forms fibers that stiffen red blood cells and cause life-threatening symptoms. Using light-scattering techniques to study the detailed thermodynamics ...

Discovery of nitric oxide delivery mechanism may point to new avenue for treating high blood pressure

November 14, 2012
(Medical Xpress)—Researchers at the University of Virginia School of Medicine have shed new light on blood pressure regulation with the discovery of an unexpected mechanism by which hemoglobin controls the delivery of nitric ...

Nitric oxide could make blood transfusions safer

June 25, 2013
(Medical Xpress)—Blood transfusions are supposed to save lives. Doctors give transfusions to severely ill or injured people with the expectation that their conditions will improve. In fact, transfusions do not always help ...

Recommended for you

Team finds link between backup immune defense, mutation seen in Crohn's disease

July 27, 2017
Genes that regulate a cellular recycling system called autophagy are commonly mutated in Crohn's disease patients, though the link between biological housekeeping and inflammatory bowel disease remained a mystery. Now, researchers ...

Study finds harmful protein on acid triggers a life-threatening disease

July 27, 2017
Using an array of modern biochemical and structural biology techniques, researchers from Boston University School of Medicine (BUSM) have begun to unravel the mystery of how acidity influences a small protein called serum ...

CRISPR sheds light on rare pediatric bone marrow failure syndrome

July 27, 2017
Using the gene editing technology CRISPR, scientists have shed light on a rare, sometimes fatal syndrome that causes children to gradually lose the ability to manufacture vital blood cells.

Post-stroke patients reach terra firma with new exosuit technology

July 26, 2017
Upright walking on two legs is a defining trait in humans, enabling them to move very efficiently throughout their environment. This can all change in the blink of an eye when a stroke occurs. In about 80% of patients post-stroke, ...

Molecular hitchhiker on human protein signals tumors to self-destruct

July 24, 2017
Powerful molecules can hitch rides on a plentiful human protein and signal tumors to self-destruct, a team of Vanderbilt University engineers found.

Researchers develop new method to generate human antibodies

July 24, 2017
An international team of scientists has developed a method to rapidly produce specific human antibodies in the laboratory. The technique, which will be described in a paper to be published July 24 in The Journal of Experimental ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

RoMiSo
not rated yet Nov 07, 2013
Christmas gift from Transilvania to the Transilvanian King Dracula of the Vampires :-)

Congratulations to the reasearch team in Cluj!

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.