Instead of infiltrating breaks in the skin, HIV appears to attack normal, healthy genital tissue in women, U.S. researchers said on Tuesday in a study that offers new insight into how the AIDS virus spreads.They said researchers had assumed the human immunodeficiency virus, or HIV, sought out breaks in the skin, such as a herpes sore, in order to gain access to immune system cells deeper in the tissue.
This is a really important discovery as we move forward in the fight against HIV and AIDS infection. Part of me wants to scream, "Why didn't we know this earlier!?" But I realize that it isn't due to a lack of committment on the part of HIV researchers to study women, but more likely, a misconception on the part of funders about who is really affected by HIV and AIDS, i.e. EVERYONE.
Just in case you haven't seen the facts, women of color are disproportionately infected with HIV and AIDS:
- Black women and Latinas account for 79 percent of all reported HIV infections among 13- to 19-year-old women and 75 percent of HIV infections among 20- to 24-year-old women in the United States although, together, they represent only about 26 percent of U.S. women these ages.
- HIV/AIDS is the leading cause of death for black women (including African American women) aged 25-34 years.
- High-risk heterosexual contact is the source of 80% of newly diagnosed women with HIV infections.
Appalling, right? I got my big wake up call working with Marvelyn Brown on her memoir, The Naked Truth (now in its second printing!). Marvelyn was infected with HIV at 19-years-old through unprotected sex with who she thought was her "prince charming." Her entire life was turned upside down by forgoing the condom that one night.
Wrap it up ladies! Now that we know that HIV can infiltrate healthy tissue, it has become even more critical to negotiate condom use and always carry your own protection.
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Wait, does this mean that women without any STDs are actually more vulnerable to HIV than those with one?
Anyway, everyone should always use protection. And I know a lot of gay women who don't use any either. Even if we're not talking HIV, there's still a lot of reasons to protect yourself. Unfortunately, dental dams are often hard to come by. I wish they got passed out as much as condoms did.
'Part of me wants to scream, "Why didn't we know this earlier!?" But I realize that it isn't due to a lack of committment on the part of HIV researchers to study women, but more likely, a misconception on the part of funders about who is really affected by HIV and AIDS, i.e. EVERYONE.'
Or because immunology is harder than you think.
As a molecular biologist, I've worked closely with many people who are working on HIV and other immune system viruses. I think there's a dogma in the field that viruses that infect the immune system must come in direct contact with immune cells. This idea isn't wholly without merit; the vast majority of viruses must come in direct contact with the tissue type they infect, in order to infect an organism. This is why skin and mucous membranes work as infection barriers. So investigating normal epithelium as a method of entry into the bloodstream, something that was thought to be highly improbable, does require a bit of outside-the-box thinking and a way to convey it to funding agencies without sounding like a loony.
Now it's unclear if, from this study, the viral particles were able to invade past the basement membrane of the epithelium and of blood vessels, and enter the bloodstream. It's easier to move past epithelial cells than basement membranes, and two must be crossed for bloodstream entry. I'll have to look up the article. If this is what has been shown, then that's a big discovery. If not, if it's just epithelial invasion, that's been shown before (although for other, more easily-obtainable cell types), so it's more that their method of detection is new and sexy which made the research more famous.
Danyell -- I think it means that it doesn't matter whether you have any lesions (due to STDs or otherwise) or not; it's not that healthy women are *more* susceptible, they're *just as* susceptible as anyone.
it has become even more critical to negotiate condom use
"Negotiate"? How about demand.
As someone whose mother has AIDS, that is something I actually learned very early.
Ok, I'm ignorant here. How is HIV transmitted in men? Does it enter through normal tissue? What kind of tissue?
This part is a little confusing:
"Normal skin is vulnerable," Thomas Hope of Northwestern University's Feinberg School of Medicine said in a telephone interview.
...
They studied newly removed vaginal tissue taken from hysterectomy surgeries, and introduced the virus which carried fluorescent, light-activated tracers.
They watched under a microscope as the virus penetrated the outer lining of the female genital tract, called the squamous epithelium.
The vagina doesn't have any skin. Did Dr. Hope misspeak or was the study solely on the squamous epithelium?
@Daniel: This study wasn't even immunology. It was about penetration of a barrier, not about the immune response provoked. It's a fair question to ask why it took so long to test a hypothesis, especially the most fundamental hypothesis in infection in women.
@Danyell: My info may be dated, but condoms are superior to dental dams because test data exist on their effectivity as a barrier (maybe dental dam data exist now). Cut the closed end off the condom and then cut it open lengthwise, and voila, one square of latex. obvs, be very careful not to induce additional cuts or tears.
@the_becca: I can demand, maybe you can demand, but a lot of women can only negotiate. Some women aren't in a position to do even that.
Whoops, I ended italics a sentence too early.
Epithelium and skin are often used interchangably. While it's not exactly accurate to call mucous membranes skin (i.e. vaginal epithelium, oral epithelium, etc etc), I suspect he was trying to "dumb it down" to lay terms.
This is immunology. The "vaginal skin" where HIV infects is actually part of the urogenital mucosa. HIV gains entrance to healthy or undamaged parts of the mucosa by way of dendritic cells and microfold cells which specialize in importing pathogens from the mucosal surface to the body, right to pockets where lymphocytes and other immune cells are waiting to be primed. DCs and M cells are considered part of the immune system.
I learned this just last quarter in an immunology course. HIV infecting people through a healthy system like this has been known for quite sometime. The research about it was published ten years ago.
I think the fact that we didn't know about it sooner has less to do with science and more to do with media and misinformation surrounding the disease. All the more reason for comprehensive sex ed.
I learned in microbiology that scientists know surprisingly little about how HIV actually enters the body and gets to the cells it will infect.
I learned years ago in an STD education training course that HIV could go through mucous membranes, which I was also taught we found in the vagina. So this being news is confusing to me. I need to go do some research.
I have a question that I'm hoping someone in the field of science or medicine can help me with. Clearly it's critical for researchers understand disease transmission and this may have a real impact on the direction research takes, but how does this change our understanding of HIV transmission from a practical standpoint?
Although the article mentions herpes lesions as a possible entry for the virus, I had always heard that the primary pathway was through tiny vaginal tears which are unrelated to STDs. Because small breaks in tissue are basically inevitable during penetration (particularly with the friction involved in sex), it seems safe to assume that anyone woman engaging in vaginal intercourse is going to have them. If all women having vaginal sex have small vaginal tears than how has our understanding of risk changed with the idea that intact tissue is equally vulnerable? It seems the risk group would be identical. The article makes it sound as if we went from believing there had to be festering open wounds to an understanding that everyone is at risk, but I'd thought that women were always vulnerable due to tears in the tissue that occurred during regular sex. This find is obviously important from a scientific standpoint, but I'm just curious about if/how it changes things from a practical standpoint for an average person. I think there is a good chance I had some misconceptions about the old theory of HIV transmission. Hopefully someone can help shed some light on this for me. Thanks.
I too am ignorant on the physiology issues here but...
is this saying that women are more vulnerable to contract HIV than men through sexual contact? Are only women able to contract this through healthy skin and the concept that it is transmit through cuts/sores still applies to men?
I am telling you with HPV (which many of my friends are now struggling with) and all of these gendered diseases and biologically discriminating conditions -- if there is a god I sure wouldn't worship it :k
OK, I'm not a professional-- I'm an undergraduate studying biochemistry, but, I think I can shed some light on HIV infection.
HIV has multiple routes of transmission. It can enter through cuts and blood or sores, but it can also enter through the mucosa which includes airways, stomach, urogenital tract and the rectum.
The mucosa is unique because it serves as a permeable (as oppose to the skin) barrier between us and the outside world. It has specialized immunity. Certain cells in the mucosa "sample" the outside environment for pathogens, importing them from the surface of the mucosa to the inside of the body where other immune cells are waiting for them. Our bodies do this so they can mount a rapid and specific response to pathogens.
HIV exploits this natural immune mechanism. It's imported and then it infects the very immune cells (dendritic and t-cells) which are laying in wait for pathogens.
I can't say for sure why women are more vulnerable, but it's probably due to the increased mucosa surface area that's exposed for women during sex along with the general flow of things. Probably the same reason women are more prone to UTIs.
Regarding female vulnerability: When semen is deposited into the vagina, it stays there until removed (manually or through natural vaginal self-cleaning). When a penis is exposed to vaginal fluid, it is only exposed to it for the duration of the sex, after which the fluid dries out or is cleaned off (many infectious agents can't survive on dry surfaces). That makes perfect sense to me.
Also, the penis is not nearly as porous or secretory/absorbent as the vagina, which suggests to me that there is less of a potential for infectious agent permeation. Then again, the mechanism of entry into the bloodstream/body cavity may not be at all based upon the porous nature of the vag, and this might all just be garbage babbling.
Interesting. This might explain why circumcision reduces the risk of HIV infection by 60%.
Don't mean to sound like a brick-head, but I'm confused. If HIV seeks out healthy tissue in a country that contains an African American population of only 12%, then how is it that black women are contracting HIV at a higher rate than ALL other groups of women in this country? Shouldn't more white women or Hispanic or Asian women be contracting HIV based on their sheer numbers?
This new information only serves to support my theory that HIV may have been created and not something that mutated from other viruses over the years. Because to put it simply, we black people have no special affinity for contracting HIV. Me thinks there is devious manipulation behind the scenes.
Created to specifically attack blacks? If that were the case we would've seen a high rate of infection among blacks from the very beginning of the AIDS epidemic instead of just recently.
In general I think its because of reduced education about the risk of HIV contraction in the black community; the 25% rate of incarceration among young black men (wherein they contract HIV & then spread it once free); the perception within the black community that HIV is a white, gay men's problem; and a reduced use of condoms in the black community (which is also reflected in high rates of out-of-wedlock births).
Sly, if you consider the blacks from Africa (since scientists claimed that was where HIV originated) then we DID see a high rate of infection among blacks from the very beginning. How that infection among black Africans exploded into the infections among African-Americans makes no sense to me as well.
However, I don't buy the high rate of out-of-wedlock births of African Americans as evidence, because if we compare that with the rate of abortions among the rest of the female population, we would see a great number of non-African American women NOT using condoms but STILL not being infected with HIV. Introduce the idea of interracial dating and sex and you begin to see that even with high incarceration rates, HIV should inevitably spread into other communities far and beyond the African American community.
And if HIV is transmitted through healthy tissue as this article states, then there is no way that 12% of the population should constitute the majority of HIV infections.
I still believe that HIV is a disease created in a laboratory. Maybe to infect blacks or simply maybe to infect fringe populations. But this latest article only helps to support my theory.
Well, it is also possible that blacks are more susceptible to HIV infection for another reason:
"According to the results of a recent AIDS-oriented study performed by an international team of researchers, black individuals present a gene variant which, while ensuring a higher level of protection against some types of malaria, increases the body’s vulnerability to HIV infection by 40 percent."