New Delhi: A team of researchers from Delhi University has found a way to stop lab-made haemoglobin from releasing toxic chemical heme (haem). This finding is a significant step in making haemoglobin protein in the lab that will not be toxic and hence can be used as blood substitute, according to the researchers.
The research findings have been published in the Journal of Biological Chemistry.
An oxygen-carrying blood substitute, sometimes called artificial haemoglobin, is an artificially made red blood cell substitute whose main function is to carry oxygen, as does natural haemoglobin.
The lab-developed haemoglobin is believed to be a safe and portable blood substitute with multiple advantages like lower cost of production, long shelf life, blood group neutrality (can be used irrespective of blood groups), no associated risk of transmission of diseases and ease of storage.
Suman Kundu, associate professor, department of biochemistry, University of Delhi South Campus, who led the research team, told India Medical Times, “Blood is transfused from one human to another for medical therapy in conditions like trauma, surgery, battlefield wounds, accidents, blood diseases, etc. We cannot survive without blood in the long term. However, under such medical emergencies and for life-saving temporary resuscitation and recovery, one can use a substance other than blood, which can carry oxygen, since human (donated) blood is in acute shortage.”
He said, “India alone may have 2-3 million units of blood shortage than the demand. So, for medical emergencies one can use a substitute of blood to overcome the blood shortage. These alternatives are often called ‘blood substitutes’ or ‘artificial blood substitutes’ and are in no way ‘blood’. For example, instead of blood one can use a protein present in blood called ‘haemoglobin’. This protein is red in colour and is present in very high amount in blood causing it to be red in colour. Haemoglobin protein can be used as a blood substitute instead of blood under medical emergencies since this protein can transport oxygen, which is required for human survival. The protein haemoglobin can be made in the laboratory itself by molecular biology and genetic engineering methods. Now one can ask, why haemoglobin is not being used globally then as a blood substitute. This is because it has been tried and found that when haemoglobin protein is injected into human body other problems (side effects) arise — like high blood pressure, poisoning of cells, etc. Scientists in USA have worked on haemoglobin protein and have found solution to solve these problems like high blood pressure. However, one major problem still remains. It is the fact that haemoglobin, when used in human body, releases a chemical named ‘heme’ which is very toxic to the body.”
Kundu further said, “This is where our lab has been working and found a successful way to stop haemoglobin from releasing this toxic chemical (heme or haem). We have shown that this laboratory made haemoglobin can be modified or engineered in such a way that it becomes very stable and do not breakdown to produce the toxic chemical. This finding is a significant step in making haemoglobin protein in the lab that will not be toxic and hence can be used as blood substitute.”
“These were proof-of-concept experiments and now we are working together with a laboratory in USA to make the final product (haemoglobin protein) that might be used commercially. The product will need about two years to be made and patented. Then it will be tested in model animal systems and then go for human clinical trial,” he added.
Commenting on the recent media reports about the “discovery of artificial blood”, Kundu said, “The artificial blood story is being misunderstood and is getting to be more of a ‘story’ than reality. No ‘blood’ — real or artificial — has been discovered. What we really wanted to do is to raise some awareness of an alternative to ‘blood’.”
Besides Suman Kundu, the research team included PhD students Sheetal Uppal, Shikha Salhotra and Nitika Mukhi from the department of biochemistry, University of Delhi South Campus. They were helped by Rajiv Bhat, professor, School of Biotechnology, Jawaharlal Nehru University (JNU), New Delhi and his student Fatima Zaidi and by Somdatta Ghosh Dey, principal investigator, Indian Association for the Cultivation of Science (IACS), Kolkata and her student Manas Seal. They have been working on this particular problem (how to prevent artificial haemoglobin from releasing toxic chemical heme) for the last 3-4 years, according to Kundu.
by Vidhi Rathee