Could something as simple as oral care affect viral reservoirs?
Research performed at Case Western found increased levels of HIV in the saliva and blood of people who had severe periodontitis (inflammation of the gums around the teeth). They discovered byproducts of bacteria, called metabolic small chain fatty acid (SCFA), that are associated with periodontitis, which can work together to awaken dormant HIV and cause it to reactivate, leading to an increase in residual HIV.
This research is described in the article “Short chain fatty acids potently induce latent HIV-1 in T-cells by activating P-TEFb and multiple histone modifications,” published in January 2015 in the journal Virology.
The Case Western research reaffirmed earlier research conducted at the University of Kentucky that also demonstrated a strong correlation between oral bacteria and latent HIV activation in T cells. Both studies suggest a link between oral healthcare and increased HIV replication and support the importance of treating and preventing oral bacterial infections.
Additionally, oral bacteria were linked by the Case Western researchers to increased rates of Kaposi’s sarcoma-associated herpesvirus (KSHV), which is known to be associated with HIV.
The mouth is a breeding ground for bacteria. In total, approximately 700 strains of bacteria have been found to inhabit the oral cavity. Particular strains vary from person to person and depend on many factors including environment, health and the food a person eats.
Bacteria is not necessarily a bad thing. Most of the bacteria in the mouth are beneficial organisms that live in harmony with each other, maintaining a healthy microbiota (bacterial colony). It’s when “bad” strains of bacteria overtake the “good” that oral manifestations such as periodontitis, gingivitis, and infections can occur.
Periodontitis is often more severe, and can occur with an enhanced frequency, in HIV-positive individuals. It is initiated by bacterial strains that include Porphyromonas gingivalis. A higher level of these bacteria have been found in HIV-positive versus HIV-negative individuals.
Studies show that individuals living with HIV also have higher levels of a bacteria strain called Streptococcus mutans (S. mutans). S. mutans contributes to the formation of caries (the scientific term for cavities and tooth decay). Caries increase the severity of periodontitis.
A strong link has also been shown between the inflammation caused by periodontitis and oral bacterial infections and the development of cardiovascular disease. Bacteria can leak into the bloodstream and trigger inflammation. Inflammation leads to atherosclerosis (hardening of the arteries), which can cause a heart attack or stroke.
As our knowledge of the importance of microbiota in diseases such as HIV grows, additional research on the potential use of probiotics has begun to show the benefits of certain probiotics in restoring healthy microbiota. The utilization of probiotic mouthwash to restore and maintain a healthy microbiota balance in the oral cavity is growing in popularity. One such oral probiotic mouthwash, called BreathActiv, has been suggested specifically for HIV patients due to its inclusion of S. rattus JH145, which reduces S. mutans.
The importance of oral health care is often overlooked by both HIV patients and their physicians. The Case Western research suggests that more attention should be paid to maintaining a healthy balance of oral bacteria.
People living with HIV should discuss an oral health plan with their clinician as part of their holistic treatment of HIV. This may include regular visits to their dentists, early treatment of periodontitis, mouth infections and other oral manifestations common to HIV-positive patients, and the institution of prevention efforts that include daily brushing, flossing, and other methods to decrease harmful bacteria.
Further research into the extent oral bacteria have on inflammation and latent HIV activation and methods of stabilizing the oral microbiota is warranted.
By Jeannie Wraight