Aging as a Risk Factor on the Immunoexpression of Pro-Inflammatory IL-1β, IL-6 and TNF-α Cytokines in Chronic Apical Periodontitis Lesions

SIMPLE SUMMARY: Apical periodontitis often manifests as a chronic and asymptomatic disease. The formation of chronic apical periodontitis lesion (CAPL) occurs due an imbalance between microorganisms in a root canal system and a host’s immune response. The pro-inflammatory characteristic of periapical granulomas has been established; increased IL-1β, IL-6 and TNF-α has been documented. In humans over 65 years of age, the immune system becomes more fragile, including a persistent inflammatory response, making them more susceptible to reactivation of latent viruses, bacterial and viral pathogens, autoimmune diseases, opportunistic infections and neoplasms. The question of this study is as follows: in aging adults, do chronic apical periodontitis lesions as biomarkers have a risk effect on the immunoexpression of pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) compared to adults? The results demonstrated that the pro-inflammatory cytokines IL-1β, IL-6 and TNFα showed higher expression in the CAPL of the elderly than in the adult control group, thus suggesting that aging could be considered a modifier of periradicular disease. However, although aging is not the main cause for the development of CAPL, it seems to be able to influence its evolution. However, further elaborate research studies/analyses to elucidate the reasons and consequences of inflammation in the elderly are recommended. ABSTRACT: Persistent inflammatory responses in the elderly may act as modifiers on the progression and repair of chronic apical periodontitis lesions (CAPLs). While the involvement of IL-1β, IL-6 and TNF-α in inflammatory responses and, particularly, in CAPL has been documented, their expression in elderly patients needs to be further characterized. Therefore, the purpose of this study was to evaluate and compare the expressions of pro-inflammatory cytokines in CAPL from elderly individuals with young/middle-aged individuals. Thirty CAPL (15 cysts and 15 granulomas) from elderly patients (>60 years) and 30 CAPL (15 cysts and 15 granuloma) from young/middle-aged individuals (20–56 years) were selected. Immunohistochemical reactions were performed against IL-1β, IL-6 and TNF-α. The slides were subdivided into five high-magnification fields and analyzed. The number of positive stains was evaluated for each antibody. There was no significant difference between the cytokines when the cysts and granuloma were compared in the two groups. In the young/middle-aged, only IL-1β showed a difference and was significantly higher in granulomas (p = 0.019). CAPL pro-inflammatory cytokine levels in the elderly were significantly higher than in young/middle-aged individuals (p < 0.05). The pro-inflammatory cytokines IL-1β, IL-6 and TNF-α were significantly higher in CAPL in the elderly compared with the young/middle-aged group. Further elaborate research studies/analyses to elucidate the reasons for and consequences of inflammation in the elderly are recommended.