Role of Lipopolysaccharide, Derived from Various Bacterial Species, in Pulpitis—A Systematic Review

Abstract

Lipopolysaccharide (LPS) is widely used for induction of inflammation in various human tissues, including dental pulp. The purpose of this study was to summarize current medical literature focusing on (1) cell types used by researchers to simulate dental pulp inflammation, (2) LPS variants utilized in experimental settings and how these choices affect the findings. Our study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). We searched for studies reporting outcomes of lipopolysaccharide application on dental pulp cells in vitro using electronic databases: MEDLINE, Web of Science and Scopus. Having gathered data from 115 papers, we aimed to present all known effects LPS has on different cell types present in dental pulp. We focused on specific receptors and particles that are involved in molecular pathways. Our review provides an essential foundation for further research using in vitro models of pulpitis.

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“…We then indirectly verified our findings in LPS-stimulated macrophages in vitro to examine the suppression effects of EGCG on the LPS-like responses in COVID-19. Finally, our study is slightly different from the abovementioned literature (61)(62)(63)(64)(65)(66)(67) in terms of molecular signaling pathways. Based on the results of the bioinformatics analysis, we focused on the most credible MAPK (ERK1/2-JNK-P38) signaling pathway.…”

Tea Ingredients Have Anti-coronavirus Disease 2019 (COVID-19) Targets Based on Bioinformatics Analyses and Pharmacological Effects on LPS-Stimulated Macrophages

“…We then indirectly verified our findings in LPS-stimulated macrophages in vitro to examine the suppression effects of EGCG on the LPS-like responses in COVID-19. Finally, our study is slightly different from the abovementioned literature ( 61 – 67 ) in terms of molecular signaling pathways. Based on the results of the bioinformatics analysis, we focused on the most credible MAPK (ERK1/2-JNK-P38) signaling pathway.…”

“…Furthermore, EGCG-modified collagen membranes have been shown to downregulate the expression of inflammatory factors and promote M2 (CD163 and CD206) macrophages ( 66 ). EGCG also stimulates LC3-II production and autophagosome formation and inhibits LPS-induced upregulation and extracellular release of HMGB1 ( 67 ). Our results are consistent with those described above; however, the origins of the abovementioned research and our study are different.…”

Different expression patterns of inflammatory cytokines induced by lipopolysaccharides from Escherichia coli or Porphyromonas gingivalis in human dental pulp stem cells

“…As LPSs of different bacteria have been used in these studies, it is imperative to understand the discrepancy of the inflammation-inducing property between E. coli and P. gingivalis LPSs when interpretting and comparing these results. According to a most recently published systematic review [ 35 ], despite 105 in vitro studies using LPS in induction of pulp cell inflammation have been reported so far, only 2 experiments adopted both E. coli and P. gingivalis LPSs in stimulating heterogenous dental pulp cells [ 36 , 37 ]. Moreover, scarce evidence exists comparing the inflammatory effects of E. coli and P. gingivalis LPS on DPSCs.…”