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

ABSTRACT

Background: Hydrogen sulfide(H₂S) is a bacterial metabolite produced as a result of bacterial growth in subgingival pockets, suggested to partake in the pathogenesis of periodontitis. H₂S has previously been shown to induce the secretion of the pro-inflammatory cytokines IL-1β and IL-18 via the NLRP3 inflammasome in monocytes.

Objective: To investigate the non-NLRP3 inflammasome-dependent immunological response of human peripheral blood mononuclear cells (PBMCs) of periodontitis patients and healthy controls exposed to H₂S in vitro.

Methods: PBMCs of periodontitis patients(N = 31) and healthy controls(N = 32) were exposed to 1 mM sodium hydrosulfide (NaHS) at 37°C for 24 h and the secretion of cytokines was compared to resting cells. TNF-α, IFN-γ, IL-6, IL-8, IL-12p40, IL-12p70, IL-17, MCP-1, and IL-1Ra secretions were measured with Bio-Plex Pro™ Human Cytokine Assay.

Results: H₂S triggered the secretion of the pro-inflammatory IFN-γ, IL-6, IL-17, TNF-α, IL-12p40, and IL-12p70, while the reverse was seen for IL-1Ra. In addition, a higher basal secretion of IFN-γ, IL-6, IL-12p70, IL-17 and MCP-1 was seen from PBMCs of periodontitis patients compared to healthy controls.

Conclusion: The bacterial metabolite H₂S triggers the secretion of pro-inflammatory cytokines from PBMCs and may thus have a prominent role in the host-bacteria interplay in periodontitis.

KEYWORDS:

• H₂S
• periodontitis
• PBMCs
• TNF-α
• IFN-γ
• IL-6
• IL-8
• IL-12p40
• IL-12p70
• IL-17
• MCP-1
• IL-1Ra

Acknowledgments

Special thanks to Anna-Karin Östberg for help with the Bio-Plex Pro™ Human Cytokine Assay.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was supported by grants from TUA (TUAGBG-538271), Swedish Dental Society (STS) and Gothenburg Dental Society (GTS).