H₂S mediates increased interleukin (IL)-1β and IL-18 production in leukocytes from patients with periodontitis

Abstract

Background: The mechanisms involved in the interplay between the bacteria and the host cells in periodontitis are not fully understood. Aim: To investigate the effect of the bacterial metabolite H 2 S on the pro-inflammatory cytokines interleukin (IL)-1β and IL-18 from periodontitis patients and healthy controls, and to evaluate the composition of the subgingival microbiota with its capacity to produce H 2 S. Methods: Subgingival bacterial samples from patients with periodontitis (N=32) and healthy controls (N=32) were investigated for H 2 S production and bacterial composition. Peripheral blood mononuclear cells (PBMCs) were cultured in the presence/absence of 1mM H 2 S for 24h and cytokine concentrations were measured. Results: Subgingival plaque from periodontitis patients had more H 2 S producing bacteria and produced more H 2 S, than healthy controls. PBMCs exposed to H 2 S secreted significantly more IL-1ß and IL-18 (p<0.0001) than untreated control PBMCs from both groups. PBMCs from the periodontitis patients secreted higher levels of the cytokines, both spontaneously (IL-1ß p=0.0001; IL-18 p=0.09) and after exposure to H 2 S (IL-1ß p=0.03; IL-18 p=0.04), which is a new finding not previously reported. Conclusions: H 2 S, from the subgingival microbiota, can contribute to a host inflammatory response through secretion of the pro-inflammatory cytokines IL-1β and IL-18. Since this response differs between individuals, it may also reflect the susceptibility of the host to develop periodontitis.

The secretion of cytokines by peripheral blood mononuclear cells of patients with periodontitis and healthy controls when exposed to H2S

“…In addition, a difference in secretion of the majority of the examined cytokines by resting (in the absence of H 2 S) PBMCs of periodontitis patients compared to healthy controls was seen, where higher levels were detected from cells from patients with periodontitis. These results are in line with the results of IL-1β and IL-18 secretion previously investigated in the same cohort [ 18 ]. In that study, the capacity of the subgingival microbiota to produce H 2 S was also examined and was shown to be positively correlated to bleeding on probing scores of the patients.…”

“…A higher basal secretion from PBMCs of patients with periodontitis compared to healthy controls was in the present study seen for IFN-γ, IL-6, IL-12p70, IL-17, and MCP-1, showing some similarities with the results reported from measurements in gingival crevicular fluid in the aforementioned systematic review and meta-analysis that compared periodontitis patients and healthy controls [21]. Also, a statistically significantly higher secretion by resting PBMCs of the present cohort was seen for IL-1β in patients with periodontitis while there was no difference between periodontitis patients and healthy controls regarding the acute-phase protein CRP, as previously reported [18]. A lack of difference regarding the CRP levels has also been reported by other studies, while the more sensitive serum amyloid A has been shown to be detected in higher levels in periodontitis patients compared to healthy controls [26,27].…”

“…This study was approved by the Regional Ethical Review Board (Dnr 871–15) in Gothenburg, Sweden. Detailed information and clinical data of the examined subjects have previously been published [ 18 ]. Briefly, the patients diagnosed with periodontitis were examined and recruited at a specialist clinic, Department of Periodontology, Södra Älvsborgs Hospital, Borås, Sweden.…”

“…Snuff users were equally represented in both groups. Medical diseases such as high blood pressure and diabetes were reported in both groups but were more common in the periodontitis group [ 18 ].…”

“…Peripheral blood mononuclear cells (PBMCs) were isolated by centrifugation over Ficoll-Paque™ Plus density gradients (GE Healthcare Bio-Sciences AB, Uppsala, Sweden) and exposed to a hydrogen sulfide generator as previously described [ 7 , 18 ]. In brief, after a washing step in PBS, the cells were resuspended in Dulbecco’s Modified Eagle Medium + GlutaMAXTM (Gibco, Life Technologies, Paisley, UK) supplemented with 5% human serum (Sigma–Aldrich Sweden AB, Stockholm, Sweden) and penicillin–streptomycin (Invitrogen, Lidingö, Sweden).…”