Current HIV Research - Volume 10, Issue 1, 2012

Most human immunodeficiency virus (HIV) infections are acquired during sexual contact, across the genital or rectal mucosal epithelium. At present, HIV preventive strategies such as behavioral and structural interventions (e.g., counseling and condom use) or pre-exposure prophylaxis (e.g., topical microbicides or the oral administration of antiretroviral drugs) seem to be the only effective and most indicated methods a Read More

Since the beginning of the AIDS pandemic, and following the discovery of the human immunodeficiency virus (HIV) as the etiological agent of the disease, it was clear that the virus gains access to the human host predominantly through the mucosal tissue after sexual exposure. As a consequence, the female genital tract (vaginal and cervical), as well as the rectal, penile, and oral mucosae have been extensively studi Read More

Despite the identification of HIV-1 as the etiological agent responsible for AIDS nearly 30 years ago, a sterilizing vaccine capable of preventing transmission of the virus remains elusive. In response to struggles on the vaccine development front, significant effort has been devoted to preventing the transmission of HIV with alternative products, technologies, and strategies. One of the early alternative HIV prevention st Read More

Preventing the transmission of human immunodeficiency virus (HIV) is the main goal of numerous studies trying to develop an effective vaccine and microbicide agents. Here we review the use of antiretroviral drugs to inhibit viral entry as potential HIV microbicides. After the failure of nonoxynol-9 microbicide strategies shifted towards the use of compounds creating a physical barrier to virus attachment (e.g., surfacta Read More

The CAPRISA 004 study in South Africa has accelerated the development of vaginal and rectal microbicides containing antiretrovirals that target specific enzymes in the reproduction cycle of HIV, especially reverse transcriptase inhibitors (RTI). In this review we discuss the potential relevance of HIV-1 RTIs as microbicides, focusing in the nucleotide RTI tenofovir and six classes of nonnucleoside RTIs (including dapivirine, UC781, Read More

Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections including HIV-1. Despite more than two decades of HIV-1 research, there is still no efficacious HIV-1 vaccine, and the scientific community appears sceptical about the short or long-term feasibility of developing a vaccine that has t Read More

The new generation of microbicide candidates is based on the use of antiretroviral (ARV) drugs. The first compounds tested were selected among ARV classes that block the early stages of viral replication cycle, either entry/fusion or reverse transcription. Recently, an additional class of ARVs acting on a later step of viral replication has entered the microbicide pipeline, the protease inhibitors (PIs). This class of ARVs has shown Read More

Tenofovir, a highly prescribed drug for the treatment of HIV/AIDS infections, has recently also shown its effectiveness as a potential topical microbicide drug in the prevention of HIV transmission. Here, we discuss the combination of tenofovir with various other antiretrovirals (ARV) highlighting the large class of carbohydrate-binding agents (CBAs) targeting the glycans on the viral envelope gp120 for their anti-HIV ac Read More

Despite advances in the treatment of HIV infection, heterosexual transmission of HIV remains high, and vaccines to prevent HIV acquisition have been unfruitful. Vaginal microbicides, on the other hand, have demonstrated considerable potential for HIV prevention, and a variety of compounds have been screened for their activity and safety as anti-HIV microbicides. Among these are the naturally occurring host defense peptide Read More

Here, we review the armamentarium on in vitro/ex vivo models of HIV sexual transmission and discuss how these models can be applied to study candidate microbicides.

There have been encouraging recent successes in the development of safe and effective topical microbicides to prevent vaginal or rectal HIV-1 transmission, based on the use of anti-retroviral drugs. However, much work remains to be accomplished before a microbicide becomes a standard element of prevention science strategies. Animal models should continue to play an important role in pre-clinical testing, with Read More

The development of pre-exposure prophylactics or microbicide products for the reduction or elimination of the sexual transmission of HIV has numerous challenges or barriers to success. Historically traditional dosage forms such as gels have been developed in the field but more recently controlled release dosage forms such as vaginal rings and novel dosage forms such as polymeric thin films have been studied. Studies h Read More

Throughout the world, and especially in countries comprising the developing world, women are now bearing the brunt of the HIV pandemic, with over 50% living with HIV infection primarily contracted through sexual transmission in monogamous relationships. Thus, effective chemical or physical means of preventing HIV transmission are urgently needed and in the absence of an approved and effective vaccine, microbici Read More

Women account for half of new infections with HIV annually. Heterosexual transmission is the most common route of infection in resource limited settings (RLS). An effective microbicide would help decrease transmission of HIV and potentially enable women to have more control in sexual relationships. Research into microbicides is done predominantly in RLS. In addition, there will be different issues and challenges to consid Read More

As ‘proof of concept’ has now been well validated for topical microbicides, the progress has, appropriately, refined the questions of who, how, when and at what risk and cost. These are welcome challenges requiring intensified, cross-disciplinary responses. This is especially true in the areas of adherence and pharmacokinetic/pharmacodynamics (PK/PD) sampling and modeling to optimize preventive trials measuring “efficacy”, Read More