Parasite Implicated in Severe Periodontal Disease

As if there weren’t enough to worry about these days. Now we have to be on the lookout for a small parasitic amoeba capable of annihilating our gums. According to recent findings by researchers from Charite–Universitatsmedizin Berlin, Entamoeba gingivalis, a unicellular parasite, which is commonly found in our oral cavities, plays a significant role in severe tissue inflammation and destruction—the hallmarks of periodontal disease.¹ And all it takes is an infected droplet transmitted person-to-person or from something like an eating utensil.

Periodontitis often starts as gingivitis. It traditionally has been thought to stem from poor oral hygiene, which allows bacteria to proliferate. Under this scenario, bacteria buildup leads to plaque formation, which may be rampant, hardening into calculus that extends under the gumline, inflaming, infecting and damaging soft tissues. Periodontal disease can not only lead to tooth loss through destruction of bone and supportive tissues but can also systemically impact overall health due to inflammatory response.

Aside from lax oral care habits, several other factors can make development of periodontal problems more likely. These include genetics; illnesses, such as diabetes; smoking; medication use; and hormonal changes. And now there’s one more.

Bad Bug

To get an idea of the potential virulence of this amoeba, consider that it is similar to Entamoeba histolytica, which impacts the colon causing amebiasis, one of the most lethal parasitic diseases on the planet. Similarly, E. gingivalis colonizes the oral cavity, invades the oral mucosa, and essentially starts eating its way through gingival tissue. This elicits an immune response resulting in inflammation, not unlike the gastrointestinal bug.

Led by Arne Schäfer, BSc, MS, PhD, PD, head of the Periodontology Research Unit at Charité’s Institute of Dental and Craniofacial Sciences, the international team of researchers compared the frequency of E. gingivalis in 158 patients, some with periodontitis and some without, via polymerase chain reaction and microscopy. They found the parasite in 77% of those with inflammation and 22% of those in the healthy control group. An increased presence of the parasite was evident in patients with severe and recurrent periodontitis.

Path of Destruction

E. gingivalis, which tends to inhabit periodontal pockets, has long been identified as an opportunistic amoeba and nonpathogenic. However, that thinking could change. The study showed that disruption of the epithelial barrier paves the way to invasion by a host of pathogens, including E. gingivalis, into the gingival tissue. Once they’ve gained entry, the parasites destroy tissue, killing host cells. Cell cultures revealed that cellular growth rate slows upon infection with E. gingivalis to the point that the cells die.

Periodontitis has shown to be tenacious and difficult to eradicate in patients over the long term. Researchers speculate that the prolific colonization and significant virulence of this parasite may be to blame because traditional treatments haven’t considered E. gingivalis. In fact, Entamoeba species are known to be resistant to treatment agents such as antibiotics, antimicrobial peptides, and neutrophils. Therefore, if researchers can figure out how to eliminate the parasite, long-term success in treating periodontal disease may become possible.

A clinical trial to assess to what extent treatment improvements hinge on the elimination of the parasite is reportedly being conducted.

Reference

1. Bao X, Wiehe R, Dommisch H, Schaefer AS. Entamoeba gingivalis causes oral inflammation and tissue destruction. J Dent Res. 2020;99:561–567.