Posts tagged antiviral medicine

A 3D render of the HIV virus within the immune system.

The Sneaky Nature of the HIV Virus

A 3D render of the HIV virus within the immune system.

The HIV virus goes to great length to stay alive.

There is no doubt that HIV is a deadly virus. Since it was discovered, this pandemic has infected 78 million people and 35 million have died due to an AIDS-related illness. The worst part is that scientists have yet to find an absolute cure to the disease. Why is it that the HIV virus is so hard to eradicate? What is it about the disease that makes treatment difficult?

Many experts note the infection’s ability to hide within the body. HIV is notorious for eluding even the most powerful combinations of medicine. The sneaky nature of the disease allows it to wait until the right moment, when the body’s defenses are down, to attack the immune system. Even today, scientists are still trying to figure out and understand exactly how the virus works in order to combat its effects on the body.

How the HIV Virus Moves Within the Body

Once the body is infected with HIV, the virus begins to attack the immune system. It’s number one target are the CD4 cells in the body. These cells help the immune system fight off infection and diseases. Little by little, HIV lowers the CD4 count until the body can no longer protect itself.

The best defense against HIV is antiretroviral therapy (ART). This is a combination of several medications that work together to suppress HIV levels in the body. In order for this treatment to work, it has to be taken daily. When taken properly, the treatment has proven effective in reducing traces of the virus to nearly undetectable levels and preventing the progression of the disease to aids.

What Studies Have Found

ART is no cure. Traces of the virus remain within the body despite the use of these strong medications. The virus likes to hide in immune cells when at low levels. By remaining dormant in these “Sanctuary Sites,” it can wait in places unreachable by drugs. Once it has found the right moment, it will quickly reproduce when an HIV positive individual stops taking ART therapy.

In a recent joint study by the Monash Biomedicine Discovery Institute and the Systems Immunity Research Institute at Cardiff University, the two institutions discovered that mutations within HIV help it appear dormant and virtually undetectable by the immune system. These mutations change the way that key immune molecules called Major Histocompatibility Complex (MHC), display the virus.

“This work uncovers a novel mechanism for HIV immune escape, which will be important to incorporate into future vaccine development and may have broader implications for immune recognition of MHC molecules,” he said.

What You Can Do

While scientists work hard to find a way to detect and eradicate the HIV virus completely, you have to do your part to curb the spread of the virus. Protect by getting tested. Knowing is an important step. If you are HIV-negative, protect yourself by practicing safe sex and taking pre-exposure prophylaxis (PrEP). For those infected by the disease, remember to take ART daily to prevent the virus from progressing.

A bottle of the HIV drug known as abacavir.

Computer Analyzes Adverse HIV Drug Effects

A bottle of the HIV drug known as abacavir.

Scientists use technology to simulate an HIV drug and the cells.

Drugs are often a double-edged sword. While their purpose is to cure or alleviate symptoms caused, many of them come with complications. This is often the case with drugs for severe conditions such as HIV drugs.

Furthermore, HIV is one of the most troublesome diseases in the world. Medications help fight off the virus but they can also have adverse effects on the body. One of the most common drugs for HIV is abacavir. The side effects of this drug are rare but a certain portion (5 to 8 percent) of patients do experience an intense allergic reaction to it.

Abacavir is known to cause hypersensitivity syndrome. This is a life threating reaction which can cause fever, rash, nausea, vomiting, diarrhea, and abdominal pain. If patients have a particular human leukocyte antigen (HLA), these symptoms usually appear within the first two to six weeks of taking the HIV drug.

The HLA protein is a substance that induces an immune response. These proteins are located on the surface of a cell and often communicate with T-cells. If an entity other than a co-binding peptide binds to an HLA protein and changes it, the protein will deem it foreign. This signals the T-cells, and cause an immune response. Often, the abacavir drug appears as an unknown entity when it tries to bind to the cells.

Researchers Take a Closer Look at HIV Drug

A test was performed at North Carolina State University. Researchers used a computer model to get a closer look at the abacavir drug reaction on a molecular level. They wanted to see the drug’s interaction with the HLA proteins.

“There are 15,000 variants of HLA, and everyone carries some of these variants,” says Denis Fourches, assistant professor of chemistry at NC State. “HLA-B*57:01 is one of the first variants studied in the context of a drug-induced immune reaction. We know that it binds with abacavir, but little was understood about exactly what was happening structurally at the molecular level, especially in terms of the relationship with the co-binding peptide. This is a very complex system.”

The computer was able to create 3D models of the HLA protein, abacavir, and the co-binding peptides. Researchers simulated the docking process with and without co-binding peptides. They also ran simulations of the process with 13 other HIV drugs that have similar effects.

“The models allowed us to identify key atomic interactions that cause abacavir and other drugs to bind to the HLA variant protein and ultimately trigger the immune response,” Fourches says. “When you can forecast and understand the elements of the drug that enable the binding to occur, you may be able to create new active compounds that do not have that problem.”

The research team at NC state hopes that his in-depth look at binding process will provide them a better understanding of how the immune system reacts to drugs. With this knowledge, they can predict the side effects of medications. In the future, they can also build better drugs. Hopefully, they will avoid life-threatening situations.

Low Risk of Birth Defects

Low Risk of Birth Defects: HIV and Antiretroviral Medication

With new compounds and therapies expanding what can be done for individuals living with HIV, more and more infected women are looking towards pregnancy and childbirth. The combination of pregnancy and the latest antiviral medications is always a cause of concern, as we often don’t have enough data to make a definitive decision on whether a certain medicine should be given to an individual while pregnant. We also need to know when it is most likely for a mother to infect her infant, and which medicines are best at keeping the rate of infection low. Certainly, many antiretroviral drugs developed in the fight against HIV have been thought to increase the potential of birth defects in the unborn children. A new study, however, shows the opposite. Indeed, it confirms a low risk of birth defects by antiretroviral medications used during pregnancy.

This study – the Pediatric HIV/AIDS Cohort Study (PHACS) Surveillance Monitoring of ART Toxicities (SMARTT) study – released its findings on 10 November 2014. Atazanavir was the only antiretroviral drug that was shown to increase the otherwise low risk of birth defects among HIV-positive women. This medication showed a 2-fold increase in the risk of birth defects, particularly musculoskeletal and skin anomalies. However, another study confirmed that at least three varied regimens of anti-HIV medications—that did not include atazanavir—was safe for women who are expecting. In fact, all other antiretroviral, anti-HIV medications tested in these studies showed no increase in the risk of birth defects. This is great news for HIV infected women who still want to become mothers. With the risks of infecting their child minimal, and the side effects almost non-existent, the hopes of researchers are high that we will find ways to altogether eliminate the transfer of HIV between mother and child.

Alternative HIV Regimens

Alternative HIV Regimens: For Those Unable to Use Efavirenz

The most commonly prescribed HIV therapies includes efavirenz, which is one of the key ingredients in stopping the spread of HIV cells through the body and keeping the immune system functioning and optimal. Efavirenz is never prescribed alone, however in combination with other anti-HIV drugs it has proven to have the greatest overall results in keeping the HIV viral load down and the immune response minimal. Unfortunately, the side effects can prevent some people from taking efavirenz. The adverse effects can include insomnia, nightmares, confusion, memory loss, headaches and depression. Along with these psychiatric disorders, efavirenz has also been known to cause birth defects in children whose mothers used the drug. Because of these consequences, it is highly recommended that anybody who suffers from certain psychiatric conditions, or any woman who believes they are pregnant, or are trying to pregnant, should not take efavirenz. Luckily, for patients who are HIV positive and unable to take efavirenz, there are alternative HIV regimens found to be effective in keeping the virus under control and unable to attack the immune system.

Researchers at the AIDS Clinic Trials Group (ACTG), have conducted a Phase III, randomized study of regimens which do not use efavirenz. They studied three different therapies given to over 1,800 HIV positive adults. The results were uniformly positive. The in-depth study closely followed the participants for 96 weeks. At the end of the study, it was ascertained that all three regimens were effective in keeping the viral loads down and keeping the immune systems healthy. There were variations in how easily patients were able to withstand any negative effects of the drugs while still gaining all of the positive effects. One regimen was clearly superior in this category – the raltegravir-based therapy – but all three were reasonable for lifelong medical regimens. These alternative HIV regimens that are effective in patients not eligible for efavirenz has provided another outlet of hope for first line defense against HIV infection.

HIV Infected Stimulant Users

HIV Infected Stimulant Users: Treatment Benefits

Some studies in the mid 90’s pointed to evidence that stimulants – such as cocaine or methamphetamine – were causing the antiretroviral therapy to be less effective against HIV. For example, HIV infected stimulant users were developing AIDS more frequently than non-using infected. The most recent studies, however, have shown that this evidence was misleading, and that antiretroviral medication does indeed have the same effects on stimulant users and non-users. The evidence was not taking into account the difficulty many stimulant users, especially those who abused these kinds of drugs, have had to obtain their needed medication. Much of this stemmed from a belief that users of these kinds of drugs would also abuse the antiretroviral medication, or would not take the medication properly.

The new data, collected between 1996 and 2012, shows that stimulant users frequently take their medication at the proper intervals, even when they are unable to lessen or stop their respective stimulant substance. This proved that not only do these infected take their medication as directed, the effects of the medication are nearly identical to non-using infected patients. The concern that still lingers concerning HIV infected stimulant users, however, is the spread of the disease due to their drug-related activities. The latest study, out of the Multicenter AIDS Cohort Study (an ongoing study of HIV infected men who have sex with men), has concluded that the biggest focus researchers should now have when dealing with HIV infected stimulant users is education and prevention. One thing the study noticed is that stimulant users are more likely to be open and forthright with their physician—if that doctor is a specialist in HIV and infectious diseases (as opposed to a general physician or one who specializes in drug use and abuse). Even when the patients are not ready to go to a group or doctor for help with their drug habits, they are ready to work with an HIV specialist to ensure their life with HIV is as healthy as possible.

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