Blood Protein from Rice

Yet another use identified for this little resource! In addition to a delicious side dish and keeping pens from going bad, scientists have been able to use rice to make albumin, a protein found in human blood.

^{Rice grains. Image Credit: kidcyber}

The demand for albumin is about 500 tons per year worldwide, and China has faced worrying shortages in the past such as in 2007 when the shortage led to price spikes and a brief rise in the number of fraudulent albumin medicines on the market. Currently, albumin is extracted from human blood donations which need thorough testing to prevent contamination and disease such as hepatitis and HIV.

The Science

Albumin is a generic term used for a type of protein which is water soluble. The protein can be found in many places in the natural world including egg whites and human blood plasma. In the human body, albumin is the most abundant protein in human blood plasma and is used to transport essential fatty acids from fat to muscle tissue. It also helps to regulate osmosis and the transport of hormones, drugs, and other substances through the blood. In medicine, is it used for treating burns, traumatic shock and liver disease.

^{Albumin Molecule. Image Credit: biowiki.edu-wiki.org}

The Discovery

The study was completed by scientists at Wuhan University in China and colleagues from the National Research Council of Canada and the Center for Functional Genomic at the University at Albany in New York. The study was published in the scientific journal of the Proceedings of the National Academy of Sciences on October 31, 2011.

The scientists genetically engineered rice seeds to produce high levels of human serum albumin (HSA) by inserting human genes into Asian rice using bacteria. This turned the plants into biological "factories" that can produce proteins that are identical to those found in humans and worked out a way to purify the protein from the seeds. Over successive generations, the amount of HSA produced in the rice increased until it was 10% of the soluble protein produced in the rice. They were able to collect 2.75 grams of the protein per kilogram (2.2 pounds) of rice. When extracted from rice seeds, the protein is "physically and chemically equivalent to blood-derived human serum albumin (HSA)," said the research in the US-published Proceedings of the National Academy of Sciences.

The derivative was tested in rats with liver cirrhosis, a common condition for which the human equivalent is often used. Scientists found that it produced similar outcomes to treatment with HSA and no adverse reactions. "Our results suggest that a rice seed bioreactor produces cost-effective recombinant HSA that is safe and can help to satisfy an increasing worldwide demand for human serum albumin," said the study.

^{Albumin. Image Credit:mims.com}

What's Next?

The "grown" HSA could be massed produced for use in hospitals, reducing the need to purify it from blood donations. The large-scale planting of genetically modified rice fields could produce enough seed for mass production of the protein, but it also raises environmental and food supply contamination concerns, since rice is a major world food staple.

However, the study authors noted that rice is a largely self-pollinating crop, pointing to previous studies that showed "a very low frequency (0.04-0.80%) of pollen-mediated gene flow between genetically modified (GM) rice and adjacent non-GM plants."

Dr Daichang Yang, the scientist who led the research at Wuhan University in central China, said: "The use of a rice seed bioreactor could provide an economical and safe approach for the production of non-animal derived compounds."

More research is needed to evaluate the safety of the rice-derived protein in animals and humans before it can be considered for the market.

Resources

What is Albumin?

Physorg.com

The Telegraph