Squeezing blood from a grain of rice

Through a feat of transgenic tweaking, scientists may have found a cheap solution to the shortage of donated blood: making blood protein from rice seeds.

In particular, the seeds could produce large quantities of a blood protein called human serum albumin (HSA) – something that’s widely used for drug and vaccine production and in treatments for severe burns, liver cirrhosis, and hemorrhagic shock.

HSA supplies, however, are limited by the amount of donated blood, which also carries a high risk of virus contamination.

Researchers worldwide have been working to create functional HSA either synthetically, with the help of yeast and bacteria, or in transgenic organisms such as cows and tobacco, Nature News reports. Part of the difficulty of producing these versions of HSA has been developing a system with a high yield, low cost, and low risk of immune reaction.

But seeds have evolved to be specialized for protein storage. You might say they are optimal bioreactors for HSA production. So, a team led by Daichang Yang from Wuhan University in China engineered rice seeds to produce lots of HSA.

1. They inserted the gene encoding HSA into rice plants, so that the gene was activated during seed production.
2. The resulting protein was stored in the rice grain along with nutrients normally used to help nurture an embryo.
3. In these crops, HSA makes up about 10% of the total dissolvable proteins of the seeds.
4. The team then came up with a way to purify the HSA, giving them about 2.75 grams of HSA per kilogram of rice.

The HSA extracted from rice was both physically and chemically equivalent to HSA derived from human blood. When they used the rice HSA to treat liver disease in rats, they found that it was as effective in relieving symptoms as blood-derived HSA.

Yang has submitted a clinical-trial application to the Food and Drug Administration and hopes to begin testing in humans within the next 2 years.

Unfortunately, as Gizmodo points out, the amount of rice necessary to manufacture a sufficient amount of the serum – worldwide consumption is 500 tons a year – would require the large-scale planting of genetically modified crops.

The study was published in the Proceedings of the National Academy of Sciences this week.

Via Nature News.

Image by papayatreelimited via Flickr

This post was originally published on Smartplanet.com