Biology 103
2001 Third Web Report
On Serendip

An infectious disease, HIV must enter the blood stream of a person for transmission. It enters through bodily fluid, such as blood, semen, vaginal fluid, and breast milk. The disease infects cells in the body, especially CD4 cells, a type of white blood cells. Also known as T-cells, CD4 cells are crucial in maintaining the human immune system in protection from infectious diseases (5). By destroying the white blood cells, HIV causes a sever breakdown of the body's immune system, leaving the body vulnerable, fragile and unable to protect against any disease they are exposed to. When the immune system becomes severely damaged AIDS is diagnosed by the contraction of specific diseases such as tuberculosis and toxoplasmosis (5). Once diagnosed with AIDS, the virus never leaves the body, leaving the immune system to deteriorate until it is unable to fight off the diseases anymore, letting them take over the body.

Major research and pharmaceutical companies continue to place precedence on the search for a vaccine or cure; it is estimated that it will take another ten to fifteen years to find a cure or vaccine for HIV/AIDS. Methods for HIV prevention need to be a priority in medical research; prevention is the first step to slowing an epidemic, and an interest in vaginal microbicides, a new form of female prevention, could result in having them on the market in a third of the time it would take to discover a vaccine (1). Trust lacks in the support for the new form of prevention, the simplicity of vaginal microbicides, called by some "kitchen table science", puts reason for doubt in major researchers (1).

Prevention is usually focused around sexual activities, because HIV transmission is more likely to occur during sex. The lining of the vaginal canal, mouth, anus and tip of the penis are fragile and easily broken parts of the body, a prime region for exchange of bodily fluid and infection of HIV. Currently, the primary form of HIV prevention during sexual activity is the condom. Men are the general targets for HIV prevention, especially gay men in the U.S. Men. Fewer complexities than the female, and an external organism, researchers opt for prevention through male genitalia. In the new microbicide research, the products created respond to the growing need for female heterosexual transmission prevention by being applicable for both genders, with special attention to the female needs.

Microbicides are a broad range of products that prevent viral infections, especially Sexually transmitted diseases. In this case thy are used as HIV pathogen infection prevention when applied in the vagina or rectum. Different Microbicides perform different actions; "They can block infection by creating a barrier between the pathogen and the vagina. They can kill or otherwise immobilize pathogens. Or they can prevent a virus from replicating once it has infected the cells that like the vaginal wall (6)." Many microbicides under development combine these different actions, taking the form of gels, creams, suppositories, films, sponges or a vaginal ring (1).

A microbicide that fights against one STD may not necessarily work against another. STDs are caused by different pathogens, while microbicides work against a single pathogen. In order to fight all or many STDs a microbicide must be invented to stop multiple pathogens. To create such a product challenges would arise in making something that is highly effective in preventing infection but does not pose possible irritation or toxicities (6).

Microbicides are currently not yet available to the public market. The complicated process of preliminary phases of research testing, though necessary to secure the safety and accuracy of the products, can take up to three or four years. Testing the efficacy of microbicides, the three phases of clinical trials present many obstacles a product must pass before FDA approval to send them to the public markets. Before the clinical trials are conducted, preclinical laboratory tests are preformed "to demonstrate the compound's general safety and potential effectiveness (6)." The microbicide product must be tested for safe reactions in exposure to other contraceptives, such as the condom. Once the product has passed the preclinical laboratory test it moves into phase one of clinical trials. This study tests a small controlled sample of twenty to eighty human volunteers on the comfort of the product; observations are made on the body's reaction to product in terms of irritation. Dosage, absorption, distribution and the lasting time in the body are among the issues examined. The second and third phases observe the same issues of safety, effectiveness and comfort as in phase one, though each testing larger volunteer samples. Health professionals monitor the third phase, which tests a few thousand participants, to confirm reactions, safety and efficacy of the product and to report all possible harmful reactions.

Currently, many products are being perused through the pipeline, the stages of research development. The number of possible products is endless. Some of the microbicide products under development are effective, and many fail. An vaginal ideal microbicide would be effective and safe for preventing multiple sexually transmitted diseases, as well as non-toxic, tasteless, odorless, colorless, inexpensive and available internationally. In the stages of development, along with safety and efficacy, bodily irritation and toxicity of vaginal microbicides are a fundamental concern. The issue of comfort is essential when developing products that work in sensitive and delicate areas. If a product is uncomfortable a person will refrain from usage. Many issues come into play when developing vaginal microbicides, as reflected in the wide range of products under development.

Antibiotic peptides kill off pathogens before infection of the body occurs, if applied in concentrated quantities to the site at which the HIV infection would occur. They are protein molecules that fight off infectious bacteria, and exist all over the surface of the body (6).

Instead of destroying the pathogens, Buffer Gel maintains the acidic level of the vagina. Interaction with the basic level of semen (which is alkaline) during sexual intercourse brings the normal pH of the vagina (around 4.2) to a basic level. HIV cannot survive in the normal in the normal environment of the vagina because it is too acidic. The change from acidic to basic during intercourse creates a prime environment for HIV transmission. The Buffer Gel will maintain the acidic level in the vagina during intercourse to prevent the HIV pathogens from passing into the vaginal and cervical epithelium (1). Similar to the Buffer Gel, the Carraguard creates a barrier to prevent HIV from entering the vaginal epithelium. A tasteless gel that coats the vagina, Carraguard is inexpensively made from carrageen, a seaweed extract. Current research shows that Carraguard is non-contraceptive. Another gel is known as the "Invisible condom"; serving as a barrier against viruses and bacteria, it is non-toxic and polymer-based. Pro-2000 Gel works in a similar format as the "invisible condom" by disrupting the binding of the virus to the cells. The gel contains a synthetic polymer that disrupts the binding to the cells, by binding to the HIV virus itself. This gel is thought to work for other STDs as well (1).

Spermicides such as nonoxynal-9, octoxinal-9 and menfegol, have been shown to contain anti-viral and antibacterial mechanisms and they are currently being evaluated as microbicides to see if the will prevent infection of HIV (3). It has been found that they kill the HIV virus in a test tube, further investigations must be conducted on its human efficacy. Research has shown that Nonoxynal-9 does not prevent HIV and might even slightly increase a woman's risk of being infected, as presented at the International AIDS conference (1). Advantage S, a spermicidal containing 52 mg. of Nonoxynol-9 (N-9), has been found to create small lesions and disruptions in the epithelium, the vaginal cell wall. Studies continue to finalize the effectiveness or ineffectiveness of the biodetergant N-9 (1).

Beyond N-9, which was developed as a contraceptive, not a microbicide, other detergents and surfactants are being tested as potential microbicides. A detergent compound works by disrupting cell membranes and viral envelopes of viruses. Products used in spermicides (such as octoxynol-9), shampoos and toothpastes (sodium dodecyl sulfate), and contact lens solution (benzalkonium) are being explored, with the advantage that they have had previous exposure to the human body and are known to generally not cause irritation (1).

Other forms of microbicides employ all-natural products, such as plants, blue-green algae and seaweed. The natural products usually come in the form of a gel and are inexpensive and gentle on the body (6). Also product that were previously used as potential AIDS therapies, for example anti-retroviral drugs, are possible candidates for vaginal microbicides. Some microbicides perform contraceptive actions and defense against STDs along with basic HIV prevention.

The more products that come down the developmental pipeline, the greater the chance one will prove effective and contain the desirable qualities of the ideal vaginal microbicide to prevent the infection of HIV. Further research must be conducted in vaginal and rectal ecology, safety and immunity, to expand microbicide development (1). Politically, socially and biologically, vaginal microbicide are in demand by women to prevent HIV transmission. Biological factors make women more vulnerable to HIV infection. Women have more genital mucosal surface exposed during intercourse allowing a greater amount of HIV pathogens to be introduced by sperm to the vaginal regions. Women are also more vulnerable to sexually transmitted infections than men (2). In social context, women are not to discuss sexuality or sexual issues; "many women cannot request, let along inisit on using a condom or and form of protection." If women refuse sex or insist on using a condom, the situation in many societies will result in violence or social outcast. Ideally, physical and material independence and public education will make a difference in prevention HIV transmission. "Women are at a disadvantage, both in terms of greater biological and social susceptibility, and lover degree of control over methods of prevention." (4)Thus, a form of easy, unnoticeable and economically affordable protection is necessary in preventing infection in women (2; the development of microbicides is the best hope.

Attraction to vaginal microbicides continues to rise. One in four sexually active women express an interest in using vaginal microbicides (6). As the HIV epidemic spreads, women need a form of prevention compatible for the biology of their body and to support social circumstances. While awaiting the cure for HIV, microbicides are the temporary answer to prevention for women. Further fundraising, government and research support is needed before the spread of the epidemic comes to a halt.

WWW Sources

2) Bulletin of Experimental Treatments for AIDS. , Women and HIV/AIDS

3)Center for Disease Control and Prevention, CDC National Center for HIV, STD and TB prevention; Divisions of HIV/AIDS Preventions.

4)Center for Disease Control and Prevention, 1999 National HIV Conference. Abstract 294

5) HIV INSITE website.

6) The Alan Guttmacher Institute publication on microbicides.

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