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Key word being "prevent", not prolonged, used in any context. Mice, but it's a step.
07:05 PM CST on Monday, January 14, 2008
By SUE GOETINCK AMBROSE and SHERRY JACOBSON / The Dallas Morning News
After 25 years of confounding researchers around the globe, scientists in Dallas have shown that HIV transmission can be stopped with medications.
Also Online
Link: Entire UT Southwestern study
The scientific first, although performed only in lab mice, bodes well for a future where people at high risk for HIV infection would have a convenient way to protect themselves from the virus.
Even though the experiment – which involves two commonly prescribed drugs for AIDS – could represent a breakthrough in AIDS prevention, experts who have long advocated safe-sex practices are worried that people will seek these drugs without waiting for scientific proof from human studies.
"This has the potential to undermine years of safe-sex reinforcement and risk reduction," said Bret Camp, associate executive director for the Resource Center of Dallas, which operates several AIDS programs.
One of the drugs, tenofovir, is reportedly being sold at gay dance clubs on both coasts as a protection against HIV. Mr. Camp said he didn't know if the drug is also being used that way in Dallas, but said it was likely.
"I'm sure it's happening everywhere, maybe to a lesser extent here than in other places," he said. But as word of this and other similar studies gets out, "there's a huge potential for abuse."
J. Victor Garcia, the UT Southwestern Medical Center microbiologist who led the study, said he does not want the study to be misinterpreted.
"This is a mouse experiment," he said. "It cannot, under any circumstances, be extrapolated to humans directly."
In fact, government-funded studies to see if a similar approach will protect people from HIV infection are still incomplete. Results are expected as early as 2009. About 40,000 Americans become infected with HIV every year; more than a million are living with AIDS.
If the medications prove effective in stopping HIV infection, "they would be much more easily deployed" than other prevention methods, said Dr. Warner Greene, director of the Gladstone Institute of Virology and Immunology at the University of California, San Francisco.
Someday, people at high risk of HIV infection could be encouraged by doctors to take a daily pill, the way they are now urged to use a condom, he said.
Other researchers said Dr. Garcia's new study, released Monday in the open-access journal PLoS Medicine, was a significant step in the worldwide effort to combat the spread of the virus.
Previous successes have stopped transmission only of related viruses, not HIV itself.
"Here for the first time we're really looking at the virus that grows in humans," said Jim Turpin, a microbiologist with the division of AIDS at the National Institute of Allergy and Infectious Diseases in Bethesda, Md. "That is very significant for us."
The experiment involved injecting five mice for seven days with two drugs that are commonly used to treat AIDS patients, tenofovir and emtricitabine. On the third day, the mice were inoculated vaginally with HIV, to mimic how most women and girls become infected.
"Women have no way of protecting themselves from STDs (sexually transmitted diseases) and HIV," said Dr. Garcia, a professor of internal medicine. A preventive medication "would empower them to at least have a fighting chance."
After three months, none of the mice showed any signs of the virus. However, seven out of eight mice that did not receive the medicine became infected after HIV inoculation.
"He gets a remarkable finding," said microbiologist Thomas Folks of the Southwest Foundation for Biomedical Research in San Antonio. "I think the fact that you can pre-expose these animals to the drugs and not get any transmission is what we're looking for in trying to blunt the epidemic.
"I don't think we can eradicate it this way, but I think we can reduce a lot of the transmission with this type of approach."
HIV normally is spread from an infected person via unprotected sexual contact, usually anal or vaginal, as well as from contaminated needles often shared by IV drug abusers. It can also pass from mother to child during childbirth.
Easy-to-use preventive measures are sorely needed to slow the spread of HIV. In recent years, the Bush administration has pushed for the so-called ABC approach – abstinence from sexual activity, being faithful to a single partner and correct and consistent condom use.
"In the prevention world, condoms work but aren't used," said Dr. Warner of the Gladstone Institute. "There's only a 15 to 20 percent compliance rate with condoms. Women targeted by the virus in many parts of the world can't dictate whether their partners use a condom."
Male circumcision has also been shown to be more than 50 percent effective in protecting men from infection via heterosexual intercourse. But, Dr. Warner noted, "It's hard to get adult males all over the world circumcised. It's not going to be the magic bullet to prevention."
And despite numerous attempts, there are no vaccines or suppositories that would kill virus the way a spermicide kills sperm. In fact, late in 2007, researchers halted a trial of what was considered the most promising HIV vaccine when they could find no protective effect.
In the laboratory, scientists also have struggled to find better ways to study the virus. Studying HIV infection in lab animals has been difficult because the virus does not naturally infect mice or rats. Monkeys are also immune, although they are susceptible to SIV, a related virus.
An important step toward the current UT Southwestern study was Dr. Garcia's 2006 development of a mouse that had been made susceptible to HIV via transplantation of a "humanized" immune system, the natural target of the AIDS virus.
That feat set the stage for the current work and will allow researchers to test different combinations of drugs and doses in lab animals as they search for a way to blunt the AIDS epidemic. An estimated 33 million people are infected worldwide.
There are more than two dozen drugs that can treat HIV infections. The two used in the UT Southwestern study are often packaged as a single medication, Truvada. Both were chosen because they are effective and convenient – each is taken by mouth once a day, and they have fewer side effects than other HIV treatments.
The two drugs are part of several studies in people, funded by the U.S. government, that are testing both safety and effectiveness in preventing HIV infection among intravenous drug abusers, young men and women who are sexually active and men who have sex with men. Test sites include San Francisco, Atlanta, Botswana, Thailand, Peru and Ecuador.
Those studies are considered the "gold standard," said Dr. Lynn Paxton, the epidemiologist at the Centers for Disease Control and Prevention in Atlanta, who coordinates the human prevention studies.
New and better animal models, such as Dr. Garcia's, are very useful but "we won't know how good any of these models is until we get the results from the human trials," she said.
"Monkeys aren't little humans and neither are mice," Dr. Paxton noted. "The proof of the pudding will be in the [human] trials."
THE DRUGS
Food and Drug Administration approves tenofovir, or Viread, in 2001 as a treatment for HIV infection. More than 150,000 infected people around the world use the drug to stop the replication of the virus. The drug's side effects include acute kidney failure.
Emtricitabine, or Emtriva, was approved in 2003 as a treatment for HIV infection in adults only. It reduces the amount of virus in the body and boosts the immune system. The most common side effects are diarrhea, headache, nausea and rash.
Truvada is a combination of tenofovir and emtricitabine approved in 2004 as a single-dose medication for HIV infection. It attacks the virus in the body and is being studied in mice and humans as a possible HIV-preventive treatment.
THE STUDY
UT Southwestern Medical Center and the National Institutes of Health funded the tenofovir-emtricitabine mouse study. Other UT Southwestern researchers who participated in the research were Paul Denton, Zhifeng Sun, Florence Othieno, Bangdong Wei, Anja Wege, Daniel Powell, Deborah Payne and Ashley Haase.
SOURCES: The Centers for Disease Control and Prevention and UT Southwestern Medical Center
THE RAVAGES OF HIV/AIDS
•33 million – number of people living with HIV/AIDS worldwide.
•1,039,000 to 1,185,000: – number of people in the U.S. living with HIV/AIDS in 2003.*
•40,000 – number HIV/AIDS cases diagnosed annually in the U.S.
•1,162 – number of new AIDS cases in Dallas County in 2006.
•20 – number of AIDS-related deaths in Dallas County in 2006.
•80 – percentage of U.S. female cases resulting from heterosexual contact.
•67 – percentage of U.S. male cases resulting from homosexual contact.
•49 – percentage of 2005 U.S. cases diagnosed in blacks, the ethnic group with the most AIDS cases.
•3-to-1 – ratio of male to female cases diagnosed each year in the U.S.
•1-to-1 – ratio of male to female cases diagnosed each year worldwide.
*Latest figures from the Centers for Disease Control and Prevention.
SOURCES: CDC, Dallas County Health and Human Services, UNAIDS/World Health Organization
By SUE GOETINCK AMBROSE and SHERRY JACOBSON / The Dallas Morning News
After 25 years of confounding researchers around the globe, scientists in Dallas have shown that HIV transmission can be stopped with medications.
Also Online
Link: Entire UT Southwestern study
The scientific first, although performed only in lab mice, bodes well for a future where people at high risk for HIV infection would have a convenient way to protect themselves from the virus.
Even though the experiment – which involves two commonly prescribed drugs for AIDS – could represent a breakthrough in AIDS prevention, experts who have long advocated safe-sex practices are worried that people will seek these drugs without waiting for scientific proof from human studies.
"This has the potential to undermine years of safe-sex reinforcement and risk reduction," said Bret Camp, associate executive director for the Resource Center of Dallas, which operates several AIDS programs.
One of the drugs, tenofovir, is reportedly being sold at gay dance clubs on both coasts as a protection against HIV. Mr. Camp said he didn't know if the drug is also being used that way in Dallas, but said it was likely.
"I'm sure it's happening everywhere, maybe to a lesser extent here than in other places," he said. But as word of this and other similar studies gets out, "there's a huge potential for abuse."
J. Victor Garcia, the UT Southwestern Medical Center microbiologist who led the study, said he does not want the study to be misinterpreted.
"This is a mouse experiment," he said. "It cannot, under any circumstances, be extrapolated to humans directly."
In fact, government-funded studies to see if a similar approach will protect people from HIV infection are still incomplete. Results are expected as early as 2009. About 40,000 Americans become infected with HIV every year; more than a million are living with AIDS.
If the medications prove effective in stopping HIV infection, "they would be much more easily deployed" than other prevention methods, said Dr. Warner Greene, director of the Gladstone Institute of Virology and Immunology at the University of California, San Francisco.
Someday, people at high risk of HIV infection could be encouraged by doctors to take a daily pill, the way they are now urged to use a condom, he said.
Other researchers said Dr. Garcia's new study, released Monday in the open-access journal PLoS Medicine, was a significant step in the worldwide effort to combat the spread of the virus.
Previous successes have stopped transmission only of related viruses, not HIV itself.
"Here for the first time we're really looking at the virus that grows in humans," said Jim Turpin, a microbiologist with the division of AIDS at the National Institute of Allergy and Infectious Diseases in Bethesda, Md. "That is very significant for us."
The experiment involved injecting five mice for seven days with two drugs that are commonly used to treat AIDS patients, tenofovir and emtricitabine. On the third day, the mice were inoculated vaginally with HIV, to mimic how most women and girls become infected.
"Women have no way of protecting themselves from STDs (sexually transmitted diseases) and HIV," said Dr. Garcia, a professor of internal medicine. A preventive medication "would empower them to at least have a fighting chance."
After three months, none of the mice showed any signs of the virus. However, seven out of eight mice that did not receive the medicine became infected after HIV inoculation.
"He gets a remarkable finding," said microbiologist Thomas Folks of the Southwest Foundation for Biomedical Research in San Antonio. "I think the fact that you can pre-expose these animals to the drugs and not get any transmission is what we're looking for in trying to blunt the epidemic.
"I don't think we can eradicate it this way, but I think we can reduce a lot of the transmission with this type of approach."
HIV normally is spread from an infected person via unprotected sexual contact, usually anal or vaginal, as well as from contaminated needles often shared by IV drug abusers. It can also pass from mother to child during childbirth.
Easy-to-use preventive measures are sorely needed to slow the spread of HIV. In recent years, the Bush administration has pushed for the so-called ABC approach – abstinence from sexual activity, being faithful to a single partner and correct and consistent condom use.
"In the prevention world, condoms work but aren't used," said Dr. Warner of the Gladstone Institute. "There's only a 15 to 20 percent compliance rate with condoms. Women targeted by the virus in many parts of the world can't dictate whether their partners use a condom."
Male circumcision has also been shown to be more than 50 percent effective in protecting men from infection via heterosexual intercourse. But, Dr. Warner noted, "It's hard to get adult males all over the world circumcised. It's not going to be the magic bullet to prevention."
And despite numerous attempts, there are no vaccines or suppositories that would kill virus the way a spermicide kills sperm. In fact, late in 2007, researchers halted a trial of what was considered the most promising HIV vaccine when they could find no protective effect.
In the laboratory, scientists also have struggled to find better ways to study the virus. Studying HIV infection in lab animals has been difficult because the virus does not naturally infect mice or rats. Monkeys are also immune, although they are susceptible to SIV, a related virus.
An important step toward the current UT Southwestern study was Dr. Garcia's 2006 development of a mouse that had been made susceptible to HIV via transplantation of a "humanized" immune system, the natural target of the AIDS virus.
That feat set the stage for the current work and will allow researchers to test different combinations of drugs and doses in lab animals as they search for a way to blunt the AIDS epidemic. An estimated 33 million people are infected worldwide.
There are more than two dozen drugs that can treat HIV infections. The two used in the UT Southwestern study are often packaged as a single medication, Truvada. Both were chosen because they are effective and convenient – each is taken by mouth once a day, and they have fewer side effects than other HIV treatments.
The two drugs are part of several studies in people, funded by the U.S. government, that are testing both safety and effectiveness in preventing HIV infection among intravenous drug abusers, young men and women who are sexually active and men who have sex with men. Test sites include San Francisco, Atlanta, Botswana, Thailand, Peru and Ecuador.
Those studies are considered the "gold standard," said Dr. Lynn Paxton, the epidemiologist at the Centers for Disease Control and Prevention in Atlanta, who coordinates the human prevention studies.
New and better animal models, such as Dr. Garcia's, are very useful but "we won't know how good any of these models is until we get the results from the human trials," she said.
"Monkeys aren't little humans and neither are mice," Dr. Paxton noted. "The proof of the pudding will be in the [human] trials."
THE DRUGS
Food and Drug Administration approves tenofovir, or Viread, in 2001 as a treatment for HIV infection. More than 150,000 infected people around the world use the drug to stop the replication of the virus. The drug's side effects include acute kidney failure.
Emtricitabine, or Emtriva, was approved in 2003 as a treatment for HIV infection in adults only. It reduces the amount of virus in the body and boosts the immune system. The most common side effects are diarrhea, headache, nausea and rash.
Truvada is a combination of tenofovir and emtricitabine approved in 2004 as a single-dose medication for HIV infection. It attacks the virus in the body and is being studied in mice and humans as a possible HIV-preventive treatment.
THE STUDY
UT Southwestern Medical Center and the National Institutes of Health funded the tenofovir-emtricitabine mouse study. Other UT Southwestern researchers who participated in the research were Paul Denton, Zhifeng Sun, Florence Othieno, Bangdong Wei, Anja Wege, Daniel Powell, Deborah Payne and Ashley Haase.
SOURCES: The Centers for Disease Control and Prevention and UT Southwestern Medical Center
THE RAVAGES OF HIV/AIDS
•33 million – number of people living with HIV/AIDS worldwide.
•1,039,000 to 1,185,000: – number of people in the U.S. living with HIV/AIDS in 2003.*
•40,000 – number HIV/AIDS cases diagnosed annually in the U.S.
•1,162 – number of new AIDS cases in Dallas County in 2006.
•20 – number of AIDS-related deaths in Dallas County in 2006.
•80 – percentage of U.S. female cases resulting from heterosexual contact.
•67 – percentage of U.S. male cases resulting from homosexual contact.
•49 – percentage of 2005 U.S. cases diagnosed in blacks, the ethnic group with the most AIDS cases.
•3-to-1 – ratio of male to female cases diagnosed each year in the U.S.
•1-to-1 – ratio of male to female cases diagnosed each year worldwide.
*Latest figures from the Centers for Disease Control and Prevention.
SOURCES: CDC, Dallas County Health and Human Services, UNAIDS/World Health Organization
Mouse ****ers! 
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