Researchers found the thickener, carrageenan, prevented human papilloma viruses (HPV) from attaching to cells in laboratory tests. Certain strains of HPV can cause cervical cancer and genital warts.
If more studies confirm these results, researchers say carrageenan-based products may be developed and used to prevent HPV infection at low cost.
The FDA has recently approved a cervical cancer vaccine that targets HPV for the prevention of cervical cancer in women at risk. But researchers say it doesn't protect against every strain of HPV and costs about $360, which could be too expensive for use in developing countries.
In the study, published in PLoS Pathogens, researchers found that carrageenan, which is derived from red algae, fit the bill. Researchers say it was an ideal candidate for testing because the thickener is already commonly used in sexual lubricants and other topically applied products.
Normally HPV attacks cells by attaching to proteins on the cell surface and then chemically getting access to the cells. But researchers found carrageenan prevented infection by stopping the virus from attaching to the cells.
"We were floored by how much better it worked than anything else we have tested. It's effective at 100-fold lower concentration than the next best inhibitor we've found," says researcher John Schiller, senior investigator at the National Cancer Institute, in a news release.
"Our results do not prove that carrageenans will work as a practical HPV topical microbicide," cautions Schiller. "The potent inhibition of infection of cells in dishes, coupled with the fact that carrageenan-based products are already in use for genital application, are promising, but we will need to do a well-controlled clinical trial before use of any of these products as an HPV inhibitor could be recommended."
Sources: Buck, C. PLoS Pathogens, July 13, 2006 online edition. News release, Public Library of Science.
By Jennifer Warner
Reviewed by Louise Chang, M.D.
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