Gut Instinct

AIDS Healthcare Foundation Trains a Research Lens on Probiotics
by Chael Needle

“Probiotics” has become a new buzz word in the dairy aisle—at least two brands of yogurt are touting their presence. Though nowadays the “live and active cultures” associated with probiotics are often removed through pasteurization, they have always been in foods like yogurt, fermented milk and soy-based drinks. Now that they have crossed over into mainstream marketing from the world of complementary and alternative medicine, probiotics look as if they will increase in popularity in the U.S., as they have been doing since the early nineties.

Though difficult to define, probiotics are generally understood to be live microorganisms, usually bacteria, with potentially healthful benefits like some of the organisms that make up the microflora already found in the gut. Large-scale research is lacking in regards to the potentially beneficial effects of probiotics, though scientific evidence is increasingly being evaluated for their use in certain areas, like the treatment of diarrhea and infections produced by antibiotic-resistant bacteria. Some scientific studies have investigated the use of probiotics in HIV-positive patients as well as disruptions of the gut ecosystem in this same population.

AIDS Healthcare Foundation is currently investigating whether or not a probiotic strain, a Bacillus coagulans called GBI-30, might confer, in capsule form, a targeted benefit to those living with HIV/AIDS. If a benefit is found, a probiotic as a HAART adjuvant could be useful to those on antiretrovirals or those who are waiting for access.

While GBI-30, a patented strain whose name brand is Ganeden BC-30, is already used by Ganeden Biotech in its lines of digestive and immune-boosting supplements and in the food and beverage products of other companies, this three-month, double-blind, placebo-controlled clinical trial will seek to demonstrate its safety and efficacy in twenty-four HIV-positive individuals, all of whom have successfully suppressed their virus to an undetectable level with antiretrovirals but have been unable to improve their CD4 counts for months. The trial is partly funded by Ganeden.

“We are learning more and more about the interaction between our gut and our immune system,” says Dr. Homayoon Khanlou, MD, chief of medicine at AHF and the lead investigator of this pilot study, in reference to the general interest in probiotics.

“It is such complex machinery that keeps bacteria inside the intestines and, in a majority of the cases, very tightly controlled. Occasionally it gets out of control and that’s why people get illnesses. There is more and more evidence that most likely some fragments of bacteria occasionally escape—they make their way to our systemic circulation, our bloodstream—and, of course, being a foreign object, the body will try to attack it and neutralize it. That leads to inflammation.

“If you could imagine that this could happen every day or every instant, it could lead to chronic inflammation, which is a basis of cardiovascular disease. So, if you could reduce these fragments of bacteria [escaping] either by having a better immune system or by having better microflora, then hypothetically you could reduce inflammation and have an impact on cardiovascular disease.”

In this case, infection with HIV is often characterized by chronic inflammation brought on by the leakage of Gram-negative bacteria from the intestines into the bloodstream. This results in CD4 vulnerability—the disease-fighting cells are more susceptible to infection and destruction by HIV. Probiotics may reduce this leakage and therefore its harmful inflammatory response and CD4 destruction.

The challenge in the age of successful antiretrovirals, when many are living longer, says Dr. Khanlou, is the possibility of an active and ongoing chronic inflammation triggered by many factors, including HIV, and which leads to “early accelerated aging,” as manifested in cardiovascular disease, for example.

“Some patients, despite successful viral suppression and maintaining an undetectable virus for a long time, are not able to restore their immune system effectively. They will respond [to antiretrovirals], and their CD4 counts will rebound, but they will never reach higher levels [of immunity strength] that many others do.…Of course, it is quite early to predict that a simple probiotic would have any impact on this.” Dr. Khanlou points to some past studies that have shown that use of probiotics have reduced inflammation in HIV-positive patients. By looking at CD4-cell and immune inflammation markers, the aim is to accumulate more evidence that a probiotic, as an adjuvant, could show clinical improvement, by possibly reducing inflammation, reducing cardiovascular event, and potentially improving CD4 count, notes Dr. Khanlou.

“Ideally, there will be some indication that this is a good approach.…People take their antiretrovirals, they take their vitamins, they exercise, they try to eat as healthfully as possible, let’s find out what else they can do to improve their lives instead of being in a state of chronic inflammation for their rest of their lives.”

Chael Needle wrote about immunotherapies in the September issue.

October 2010

Photo © Greg Gorman