For the first time, researchers from Germany have shown that a unicellular parasite commonly found in the mouth plays a role in both severe tissue inflammation and tissue destruction.
The team from Charité – Universitätsmedizin Berlin—and whose findings are published in the Journal of Dental Research—found that most patients with severe and recurrent periodontitis (gum disease) showed an increased presence of the amoeba Entamoeba gingivalis inside their oral cavities. Once the parasite has invaded the gingival tissue, it feeds on its cells and causes tissue destruction.
Scientists have long been aware of the virulence potential of this genus of amoebae. The gastrointestinal parasite E. histolytica, for instance, causes a disease known as amebiasis, one of the most common causes of death from parasitic diseases worldwide.
“We have shown that an amoeba like E. gingivalis, which colonises the oral cavity, will invade the oral mucosa and destroy gingival tissue,” lead researcher Professor Dr Arne Schäfer said.
“This enables increased numbers of bacteria to invade the host tissue, which further exacerbates inflammation and tissue destruction.”
During their analysis of inflamed periodontal pockets, the researchers detected evidence of the amoeba in approximately 80 per cent of patients with periodontitis, but in only 15 per cent of healthy subjects.
Their observations revealed that, after invading the gums, the parasites move within the tissue, feeding on and killing host cells. Cell culture experiments showed that infection with E. gingivalis slows the rate at which cells grow, eventually leading to cell death.
The researchers concluded that the amoeba’s role in inflammation shows distinct parallels to the pathogenesis of amebiasis.
“E. gingivalis actively contributes to cell destruction inside the gingival tissue and stimulates the same host immune response mechanisms as E. histolytica during its invasion of the intestinal mucosa,” Prof. Schäfer said.
“This parasite, which is transmitted by simple droplet infection, is one potential cause of severe oral inflammation.”