Posts tagged HIV/AIDS
HIV Cells in Semen Infect Through RNA Transmission
9 years ago
In early 2010, scientists at the University of California San Diego’s Center for AIDS Research (CFAR) discovered that seminal HIV infection among men who have sex with men is transmitted through the HIV cell’s RNA, and not the DNA as was previously thought. Later that year it was determined that this is also the case for women who are infected through sex with men – that is, through HIV cells in semen transmitting their RNA structure to the newly infected individual. Understanding this connection is critical, because, “If we want to stop the HIV epidemic, then we must know the mechanisms by which HIV uses human sex to spread,” according to the principal researcher, Davey Smith, MD, MAS. Smith is an associate professor of medicine at the University of California’s San Diego’s Division of Infectious Diseases, and is director of the CFAR’s Viral Pathogenesis Core.
The scientists made this initial discovery of the virus’s transmission by studying male partners in which one man had recently infected the other man. They compared the genetic characteristics of the HIV cells in both partners, knowing that the virus mutates at an extraordinary rate. They learned that there was more of a shared commonality between the viruses found in the seminal plasma – the semen and fluids surrounding them – than the viruses that were located in the seminal cells. HIV’s DNA is commonly found in the host’s cells, where RNA is mostly stored in the host’s plasma. With this asymmetrical commonality between the virus found in the plasma versus the virus inside the host’s cells, the scientists were able to locate the culprit of the initial transmission, which is the virus’s RNA; with this asymmetrical commonality found in every partnership of the men they studied, they determined that it is not a mix of HIV RNA and DNA infecting an individual, but that the RNA, alone, was the transmitter.
Now knowing this source of HIV transmission, scientists and researchers have been able to develop several weapons against HIV infection over the past five years. The HIV cells in semen are now understood more, and with this understanding researchers have been able to determine and develop several things. One discovery is that if a person has no detectable amount of HIV in their bloodstream, as they have been recently infected or because they are taking a successful regimen of antiretroviral medications, there can still be a contagious amount of HIV cells in their semen – and though the possibility of infection is low at that point, it is still possible. Researchers have also been able to develop vaginal gels and ointments – called vaginal microbicides – which are able to attack the HIV cell’s RNA before transmission can take place by infected semen, along with further developing antiretroviral medications which target the virus’s RNA and make it impotent towards further transmission. Though this discovery has not led to a cure within the past five years, it has certainly brought us closer to that possible cure, and has helped prevent further transmission of HIV for thousands.
How HIV Affects the Brain
9 years ago
HIV infection is known to cause several side effects as it invades the body. Because of advances in medicine, along with our overall understanding of what HIV is and how the virus works inside the human body, we have been able to prolong the side effects that was so disastrously prevalent in the 1980s and 1990s: death due to a completely compromised immune system. As we are now able to keep the virus essentially ineffective, even though we are still not able to eradicate it from the body, infected individuals are now able to live much longer than before, and many die of other natural causes before they develop AIDS from their HIV infection. With people now living longer than they were able to before, researchers have noticed slow-showing side effects that an elongated HIV infection can cause. One of the more feared, as well as least understood, side effects of HIV is its negative effects on a person’s mental abilities. To learn how HIV affects the brain, researchers out of Washington University in St. Louis have looked at one of the two leading theories on the subject.
The two leading theories on how HIV affects the brain are: 1) the early immune system’s responses to the infection which triggers a series of effects that slowly impair memory and mental function; 2) how the disease and co-infections commonly seen with HIV affect the brain independently of the HIV infection. The research team decided to focus on the co-infection theory, as they saw ways to judge whether these infections were indeed affecting the brain instead of HIV itself. Through statistical elimination, they determined the only co-infection which is common enough to affect so many HIV-infected individuals is hepatitis C. So, they looked at the effects of hepatitis C and the possibilities it has in affecting a brain when it is co-infected along with HIV. Knowing that this virus predominately attacks the liver led researcher David Clifford, MD, to rule out this theory, because he believes hepatitis C does not affect the brain in any directly negative manner. The study included almost 1,600 HIV infected individuals who roughly 400 were co-infected with hepatitis C. These patients were given two exams – one written and one physical – to determine any differences they may have in their cognitive and mental abilities. The exams looked at how the patients expressed themselves, made decisions, learned and retained new information, and controlled their body. The results were that there was no distinction between those co-infected with hepatitis C and those who were only infected with HIV. This lack of distinction was made even more impressive, according to Clifford, because those who were co-infected with hepatitis C were almost all older, had less of an education, and generally had lower reading and math scores than the others. They now feel the leading theory – that the immune system’s initial reactions of inflammation of the bowels and brain – is the correct one, and are working to prove this.
Are You More Immune to HIV Than You Thought?
9 years ago
by ADMIN
in HIV Management
For the past several decades, doctors and scientists could not understand why some people quickly get sick – and can die – when infected with HIV, while others seem to naturally resist the virus for several years with less damage done to their immune systems. Researchers at the University of Minnesota’s College of Biological Sciences and Medical School looked at the virus’s rapid-mutation ability, along with how it attacks the human immune system to replicate, and hypothesized that this distinct difference in how the virus differently affects infected individuals is somehow caused by the genetics of the infected host. In trying to understand why some are more immune to HIV than others, these researchers discovered a new crack in the HIV cell’s armor which helps explain this phenomenon.
HIV attacks the immune system in order to replicate within the infected host’s cells. It seeks out the immune system cells called T lymphocytes (T cells), and uses the cell’s molecular machinery to replicate within them, killing the cells when it is done with each cell. This infection eventually depletes the system of necessary T cells, leaving the infected host helpless to other invading viruses and bacteria. The T cells do have a defense against this, as they have an anti-virus protein in their arsenal – called APOBEC3 – which has the ability to block the HIV cell’s replication process. If they are successful, they can effectively stop the virus from replicating and eventually clear it from the system as the virus cells die off. Unfortunately, HIV has developed a counter-attack to this protein, a protein of their own – called Vif – which attach themselves to the APOBEC3 cells and trick the T cells into destroying their own protein, leaving them defenseless to the virus’s replication and destructive abilities. To learn why some seem to be able to naturally fend off the virus – at least for a lot longer than others – researchers looked closer at these proteins. They found strong clues as to why some immune systems work better against the virus than others.
Some people have a greater ability to create a version of the APOBEC3 protein, which is known as APOBEC3H. This particular form of the protein is boosted whenever someone is infected with HIV, which made the researchers believe this plays an important role in the immune system’s defense against HIV. What they found was a confirmation of this assumption, as people with a more stable accumulation of the APOBEC3H protein seem to be more naturally immune to HIV than those with a more unstable accumulation of this protein. Whenever the infecting HIV cells had a weaker version of their Vif protein (as constant mutations cause the virus to be varied in its strengths and weaknesses), the infected individual with a stable APOBEC3H protein in their T cells had a better time limiting the HIV cells from replicating. This was not the case if the infecting virus cells were equipped with a stronger Vif protein. This discovery helps scientists and doctors with a new path towards attacking HIV, with a possible road to a cure. The more we can suppress the virus’s Vif protein, the more our natural immune system has a chance to combat against the infection. Coupled with a strong antiretroviral regimen, this could help stop the virus from replicating, and possibly killing it outright.
Heroin Withdrawal Quickens the Spread of HIV, Researchers Say
9 years ago
by ADMIN
in HIV Management
With the hypothesis that heroin use contributes to a faster spread of the HIV cells in an infected person’s body, researchers out of Yale University conducted a study to look at the link between opiate use and HIV. They teamed up with scientists from Boston University and in Russia, studying participants’ CD4 count to determine their results. These results were quite different than they imagined, as the participants who claimed heavy heroin abuse had higher levels of CD4 than those who claimed only intermittent usage. With this information, the team has concluded that heroin withdrawal quickens the spread of HIV in an infected person’s body, as opposed to a steady use of the narcotic. CD4, which refers to a cluster of differentiation 4, is a specific form of protein that is typically found on immune system cells such as T helper cells and macrophages. This combination of the protein and immune cell, commonly known as white blood cells, are necessary for a healthy immune system to work properly, or at all. Because of this, the amount of CD4 protein found in a person’s body is a good indicator of how well their immune system is working, as lower amounts of these CD4 cells means a weaker or compromised immune system. Fewer CD4 cells in an HIV infected person’s body means the virus has destroyed more of the T helper cells where this glycoprotein is found.
Using this method of determining how much HIV has spread throughout an infected person’s body, the international research team looked at seventy seven participants, all from Russia, all heavy alcohol consumers, and none whom were then on antiretroviral medication. Those who self-reported no usage of heroin had a standard depletion rate of CD4 cells. This came as no surprise to the teams. What was surprising was the fact that those who reported heavy opiate usage had a slower rate of CD4 depletion than those who only occasionally used the drug. This ruled out the notion that heroin speeds up the spread of HIV cells in an infected person’s body, and opened new questions to the teams. Their conclusion is that it isn’t heroin use that speeds up the replication process of HIV – as previously believed – but that heroin withdrawal is the factor that quickens the spread of HIV. Though they cannot yet determine why this is, they do know that heroin withdrawal is one of the worst known to mankind, and like alcohol and benzodiazepines it is one of the only three categories of withdrawals which can actually kill a person. Jennifer Elelman, the lead author of the study and assistant professor at Yale School of Medicine, said, “We expected that HIV-positive patients who abused heroin on an ongoing basis would have the greatest decreases in their CD4 count,” adding that the international research team is now looking at the withdrawal process in relation to the spread of HIV. Not to leave all of their previous assumptions behind as they look at this process, Dr. Edelman continued, “We will also evaluate the effects of heroin and other opioids on other aspects of immune function.”
Life After AIDS
Life After AIDS: A Realistic Timetable
Up until 2001 and the advent of antiretroviral (ART) medications, HIV and AIDS was considered an epidemic, with death almost a certainty. Or, at least this was the case for those who were not wealthy or heavily covered by health insurance. AZT, the first popular antiretroviral drug, was extremely expensive. It was also only available in limited quantities, as manufacturers strained to produce enough of the drug for the needs of the worldwide population. This has all changed. Because of new research, a greater awareness of HIV, and insight into what the virus is and how it works, many scientists and doctors are reasonably hopeful in a future life after AIDS. In fact, some are even creating realistic timetables as to when this could be realized.
There is still no known cure for HIV infection. It is this virus – when left untreated – that causes acquired immune deficiency syndrome (AIDS). There are several drugs available today, however, which can either deactivate HIV cells or kill them outright. Through a regimen of these drugs, a person can survive with HIV for many years, even decades, without ever developing AIDS.
Moreover, this new phase of research into anti-HIV medications has resulted in an outpouring of education and understanding about the virus and disease. Certainly, the stigmas that were once attached to AIDS in the 1980’s have lessened. Because of the new treatments and changing attitudes, many have come forward to be tested who, in the past, might have assumed they would die and didn’t come forward for treatment to avoid the ‘shame’ of being HIV positive. Thanks to this domino effect of research and awareness the number of deaths from AIDS, although still unacceptably high, has been drastically reduced to 3 million per year. It has also led to fewer new infections from HIV, which numbers around 3.5 million per year.
In impoverished countries, those without adequate access to drug therapies, medical facilities, and proper HIV education, the number of deaths to AIDS along with new cases of HIV is still on the rise. This is the biggest hurdle to achieving the lofty goal of a life after AIDS. Even so, with the dramatic results in the past 13 years in countries like the United States, many are hopeful that by the later end of the 21st century, it is possible there will be no new infections. This will only happen when drugs have advanced to the point that they can completely sterilize the virus and when said drugs are accessible to everyone in the world.
