Researchers develop novel cytokine indices that reflect severity of periodontal inflammation

Periodontal disease has previously been linked to certain systemic conditions, including diabetes and Alzheimer’s disease, and cytokines play a crucial role in the pathophysiology of periodontal disease.

Since it is difficult to measure cytokines in the fluid found deep in periodontal pockets, the researchers measured a range of both pro- and anti-inflammatory cytokines found in the saliva of 67 adults aged 45 and older who had some degree of periodontal disease. They then constructed two composite indexes of salivary cytokines and determined whether the severity of periodontal inflammation was correlated with these scores. To assess inflammation, they employed the periodontal inflamed surface area (PISA) measure, which is calculated from the depth of periodontal pockets and bleeding upon probing.

“Periodontal inflammation is not just apparent upon examination, but is reflected in the patient’s saliva,” said senior author Dr Angela R. Kamer, associate professor in the Ashman Department of Periodontology and Implant Dentistry at the New York University College of Dentistry.

“Salivary cytokines are a window into the molecular make-up of the oral environment,” said lead author Dr Vera W.L. Tang, clinical assistant professor in the same department.

The researchers found that PISA scores were significantly associated with the new cytokine scores regardless of factors such as age, sex, smoking and body mass index. Additionally, they reported that a higher cytokine score reflected greater periodontal inflammation in a patient. “This demonstrates that a single score encompassing several salivary cytokines correlates with the severity of periodontal inflammation,” said co-author Prof. Leena Palomo, chair of the department.

According to the authors, more research is needed to validate the cytokine scores in patients with various health conditions and different levels of periodontal disease or health, including healthy gingivae and early-stage periodontal disease. Should the cytokine scores be validated in larger and more diverse patient populations, it could improve the understanding of periodontal disease progression and recurrence and the potential connection to other systemic conditions.

“With treatment for gum disease, such as scaling and planing, we know that the PISA score goes down. It would be interesting to see if the cytokine score also drops—or, if it persists, look into what that means,” Dr Kamer added. “Is it picking up an underlying cause, like ongoing inflammation from systemic disease? Or if someone has a hyper-inflammatory response, which we’d know from a high cytokine score, can it predict if periodontitis will recur or progress in the future? We hope to look into these questions in future research.”

The study, titled “Periodontal Inflamed Surface Area (PISA) associates with composites of salivary cytokines”, was published online on 15 February 2023 in PLOS ONE.