Tuesday, July 30, 2013

Soybean compound may prevent HIV spread

A compound found in soybeans can be used in new treatments to inhibit the deadly HIV infection, scientists claim. Researchers from George Mason University in the US found that genistein, derived from soybeans and other plants, may become an effective HIV treatment without the drug resistance issues faced by current therapies.

Genistein is a "tyrosine kinase inhibitor" that works by blocking the communication from a cell's surface sensors to its interior.

Found on a cell's surface, these sensors tell the cell about its environment and also communicate with other cells. HIV uses some of these surface sensors to trick the cell to send signals inside. These signals change cell structure so that the virus can get inside and spread infection.

But genistein blocks the signal and stops HIV from finding a way inside the cell. It takes a different approach than the standard antiretroviral drug used to inhibit HIV.

"Instead of directly acting on the virus, genistein interferes with the cellular processes that are necessary for the virus to infect cells," said Yuntao Wu, a professor with the George Mason-based National Center for Biodefense and Infectious Diseases and the Department of Molecular and Microbiology.

"Thus, it makes the virus more difficult to become resistant to the drug. Our study is currently in its early stage. If clinically proven effective, genistein may be used as a complement treatment for HIV infection," Wu said.
Researchers caution that this doesn't mean people should start eating large amounts of soy products.
"Although genistein is rich in several plants such as soybeans, it is still uncertain whether the amount of genistein we consume from eating soy is sufficient to inhibit HIV," Wu said.

Wu sees possibilities in this plant-based approach, which may address drug toxicity issues as well. Because genistein is plant-derived, it may be able to sidestep drug toxicity, a common byproduct of the daily and lifelong pharmaceutical regimen faced by patients with HIV to keep the disease at bay,
Wu said.

Typically, patients take a combination of multiple drugs to inhibit the virus. The frequency can lead to drug toxicity. Plus, HIV mutates and becomes drug-resistant. Wu and his team are working at finding out how much genistein is needed to inhibit HIV. It's possible that plants may not have high enough levels, so drugs would need to be developed, Wu said.

Urine may help regrow lost teeth

Stem cells obtained from urine could one day allow humans to regrow lost teeth, scientists claim. Chinese scientists used stem cells from urine to create tiny 'tooth buds' that when transplanted into mice grew into tooth-like structures.

Stem cells - cells which can grow into any type of tissue - are popular among researchers looking for ways to grow new teeth to replace those lost with age and poor dental hygiene.

The group at the Guangzhou Institutes of Biomedicine and Health used urine as the starting point, 'BBC News' reported. Cells which are normally passed from the body, such as those from the lining of the body's waterworks, are harvested in the laboratory. These collected cells are then coaxed into
becoming stem cells.
In the study, a mix of these cells and other material from a mouse was implanted into the animals. The researchers said that after three weeks the bundle of cells started to resemble a tooth: "The tooth-like structure contained dental pulp, dentin, enamel space and enamel organ."

However, the "teeth" were not as hard as natural teeth.  The research is not immediately going to lead to new options for the dentist, but researchers said it could lead to further studies towards "the final dream of total regeneration of human teeth for clinical therapy".

However, experts caution the goal faces many challenges. Professor Chris Mason, a stem cell scientist at University College London, said urine was a poor starting point. "It is probably one of the worst sources, there are very few cells in the first place and the efficiency of turning them into stem cells is very low. You just wouldn't do it in this way," he said.

He also warned that the risk of contamination, such as through bacteria, was much higher than with other sources of cells. The study was published in Cell Regeneration Journal.