Alexander C, Rietschel ET. Invited review: bacterial lipopolysaccharides and innate immunity. J Endotoxin Res. 2001;7(3):167–202. https://doi.org/10.1177/09680519010070030101.

Article  CAS  PubMed  Google Scholar 

Brown GC. The endotoxin hypothesis of neurodegeneration. J Neuroinflammation. 2019;16(1):1–10. https://doi.org/10.1186/s12974-019-1564-7.

Article  CAS  Google Scholar 

Di Lorenzo F, De Castro C, Silipo A, Molinaro A. Lipopolysaccharide structures of Gram-negative populations in the gut microbiota and effects on host interactions. FEMS Microbiol Rev. 2019;43(3):257–72. https://doi.org/10.1093/femsre/fuz002.

Article  CAS  PubMed  Google Scholar 

Nichols FC, Bajrami B, Clark RB, Housley W, Yao X. Free lipid A isolated from Porphyromonas gingivalis lipopolysaccharide is contaminated with phosphorylated dihydroceramide lipids: recovery in diseased dental samples. Infect Immun. 2012;80(2):860–74. https://doi.org/10.1128/IAI.06180-11.

Article  CAS  PubMed  PubMed Central  Google Scholar 

Whitfield C, Trent MS. Biosynthesis and export of bacterial lipopolysaccharides. Annu Rev Biochem. 2014;83:99–128. https://doi.org/10.1146/annurev-biochem-060713-035600.

Article  CAS  PubMed  Google Scholar 

Raetz CR, Whitfield C. Lipopolysaccharide endotoxins. Annu Rev Biochem. 2002;71(1):635–700. https://doi.org/10.1146/annurev.biochem.71.110601.135414.

Article  CAS  PubMed  Google Scholar 

Park BS, Lee J-O. Recognition of lipopolysaccharide pattern by TLR4 complexes. Exp Mol Med. 2013;45(12):e66. https://doi.org/10.1038/emm.2013.97.

Article  CAS  PubMed  PubMed Central  Google Scholar 

Park BS, Song DH, Kim HM, Choi B-S, Lee H, Lee J-O. The structural basis of lipopolysaccharide recognition by the TLR4–MD-2 complex. Nature. 2009;458(7242):1191–5. https://doi.org/10.1038/nature07830.

Article  CAS  PubMed  Google Scholar 

Maldonado RF, Sá-Correia I, Valvano MA. Lipopolysaccharide modification in Gram-negative bacteria during chronic infection. FEMS Microbiol Rev. 2016;40(4):480–93. https://doi.org/10.1093/femsre/fuw007.

Article  CAS  PubMed  PubMed Central  Google Scholar 

Needham BD, Trent MS. Fortifying the barrier: the impact of lipid A remodelling on bacterial pathogenesis. Nat Rev Microbiol. 2013;11(7):467–81. https://doi.org/10.1038/nrmicro3047.

Article  CAS  PubMed  PubMed Central  Google Scholar 

Steimle A, Autenrieth IB, Frick J-S. Structure and function: lipid A modifications in commensals and pathogens. Int J Med Microbiol. 2016;306(5):290–301. https://doi.org/10.1016/j.ijmm.2016.03.001.

Article  CAS  PubMed  Google Scholar 

Raetz CR, Reynolds CM, Trent MS, Bishop RE. Lipid A modification systems in Gram-negative bacteria. Annu Rev Biochem. 2007;76:295–329. https://doi.org/10.1146/annurev.biochem.76.010307.145803.

Article  CAS  PubMed  PubMed Central  Google Scholar 

Ahmad A, Samarani S, Kumar V. Lipopolysaccharide-acylating capacity of the gut microbiota and its potential impact on the immunopathogenesis of HIV infection. AIDS. 2019;33(4):753–5. https://doi.org/10.1097/QAD.0000000000002088.

Article  PubMed  Google Scholar 

Brix S, Eriksen C, Larsen JM, Bisgaard H. Metagenomic heterogeneity explains dual immune effects of endotoxins. J Allergy Clin Immunol. 2015;135(1):277–80. https://doi.org/10.1016/j.jaci.2014.09.036.

Article  CAS  PubMed  Google Scholar 

Ding P-H, Wang C-Y, Darveau RP, Jin L. Porphyromonas gingivalis LPS stimulates the expression of LPS-binding protein in human oral keratinocytes in vitro. Innate Immun. 2013;19(1):66–75. https://doi.org/10.1177/1753425912450348.

Article  CAS  PubMed  Google Scholar 

Vatanen T, Kostic AD, d’Hennezel E, Siljander H, Franzosa EA, Yassour M, et al. Variation in microbiome LPS immunogenicity contributes to autoimmunity in humans. Cell. 2016;165(4):842–53. https://doi.org/10.1016/j.cell.2016.04.007.

Article  CAS  PubMed  PubMed Central  Google Scholar 

Zielen S, Trischler J, Schubert R. Lipopolysaccharide challenge: immunological effects and safety in humans. Expert Rev Clin Immunol. 2015;11(3):409–18. https://doi.org/10.1586/1744666X.2015.1012158.

Article  CAS  PubMed  Google Scholar 

Freire M, Nelson K, Edlund A. The oral host-microbial interactome: an ecological chronometer of health? Trends Microbiol. 2021;29(6):551–61. https://doi.org/10.1016/j.tim.2020.11.004.

Article  CAS  PubMed  Google Scholar 

Pussinen PJ, Kopra E, Pietiäinen M, Lehto M, Zaric S, Paju S, et al. Periodontitis and cardiometabolic disorders: The role of lipopolysaccharide and endotoxemia. Periodontol. 2000;2022(89):19–40. https://doi.org/10.1111/prd.12433.

Article  Google Scholar 

Marcano R, Rojo M, Cordoba-Diaz D, Garrosa M. Pathological and therapeutic approach to endotoxin-secreting bacteria involved in periodontal disease. Toxins. 2021;13(8):533. https://doi.org/10.3390/toxins13080533.

Article  CAS  PubMed  PubMed Central  Google Scholar 

Horseman MA, Surani S, Bowman JD. Endotoxin, toll-like receptor-4, and atherosclerotic heart disease. Curr Cardiol Rev. 2017;13(2):86–93. https://doi.org/10.2174/1573403X12666160901145313.

Article  PubMed  PubMed Central  Google Scholar 

Thorne PS, Mendy A, Metwali N, Salo P, Co C, Jaramillo R, et al. Endotoxin exposure: predictors and prevalence of associated asthma outcomes in the United States. Am J Respir Crit Care Med. 2015;192(11):1287–97. https://doi.org/10.1164/rccm.201502-0251OC.

Article  CAS  PubMed  PubMed Central  Google Scholar 

Thorsen J, Rasmussen MA, Waage J, Mortensen M, Brejnrod A, Bønnelykke K, et al. Infant airway microbiota and topical immune perturbations in the origins of childhood asthma. Nat Commun. 2019;10:5001. https://doi.org/10.1038/s41467-019-12989-7.

Article  CAS  PubMed  PubMed Central  Google Scholar 

Doreswamy V, Peden D. Modulation of asthma by endotoxin. Clin Exp Allergy. 2011;41(1):9–19. https://doi.org/10.1111/j.1365-2222.2010.03628.x.

Article  CAS  PubMed  Google Scholar 

Louis R, Satia I, Ojanguren I, Schleich F, Bonini M, Tonia T, et al. European Respiratory Society guidelines for the diagnosis of asthma in adults. Eur Respir J. 2022;60:2101585. https://doi.org/10.1183/13993003.01585-2021.

Article  Google Scholar 

Global Initiative for Asthma. Global strategy for asthma management and prevention. 2022. www.ginasthma.org. Accessed 10 Dec 2022.

Lundberg JO, Govoni M. Inorganic nitrate is a possible source for systemic generation of nitric oxide. Free Radic Biol Med. 2004;37(3):395–400. https://doi.org/10.1016/j.freeradbiomed.2004.04.027.

Article  CAS  PubMed  Google Scholar 

Malinovschi A, Janson C, Holm L, Nordvall L, Alving K. Basal and induced NO formation in the pharyngo-oral tract influences estimates of alveolar NO levels. J Appl Physiol. 2009;106(2):513–9. https://doi.org/10.1152/japplphysiol.91148.2008.

Article  CAS  PubMed  Google Scholar 

Smit LA, Heederik D, Doekes G, Wouters IM. Exhaled nitric oxide in endotoxin-exposed adults: effect modification by smoking and atopy. Occup Environ Med. 2009;66(4):251–5. https://doi.org/10.1136/oem.2008.042465.

Article  CAS  PubMed  Google Scholar 

Fonseca SG, Romão PR, Figueiredo F, Morais RH, Lima HC, Ferreira SH, et al. TNF-α mediates the induction of nitric oxide synthase in macrophages but not in neutrophils in experimental cutaneous leishmaniasis. Eur J Immunol. 2003;33(8):2297–306. https://doi.org/10.1002/eji.200320335.

Article  CAS  PubMed  Google Scholar 

Chen Q, Lin S, Song C. An adaptive and robust test for microbial community analysis. Front Genet. 2022;13:846258. https://doi.org/10.3389/fgene.2022.846258.

Article  PubMed  PubMed Central  Google Scholar 

Svanes C, Johannessen A, Bertelsen RJ, Dharmage S, Benediktsdottir B, Bråbäck L, et al. Cohort profile: the multigeneration Respiratory Health in Northern Europe, Spain and Australia (RHINESSA) cohort. BMJ Open. 2022;12(6):e059434.

Article  PubMed  PubMed Central  Google Scholar 

ATS/ERS recommendations for standardized procedures for the online and offline measurement of exhaled lower respiratory nitric oxide and nasal nitric oxide, 2005. Am J Respir Crit Care Med. 2005;171(8):912–30. https://doi.org/10.1164/rccm.200406-710ST.

Horváth I, Barnes PJ, Loukides S, Sterk PJ, Högman M, Olin A-C, et al. A European Respiratory Society technical standard: exhaled biomarkers in lung disease. Eur Respir J. 2017;49(4):1600965. https://doi.org/10.1183/13993003.00965-2016.

Article  CAS  PubMed  Google Scholar 

Dweik RA, Boggs PB, Erzurum SC, Irvin CG, Leigh MW, Lundberg JO, et al. An official ATS clinical practice guideline: interpretation of exhaled nitric oxide levels (FeNO) for clinical applications. Am J Respir Crit Care Med. 2011;184(5):602–15. https://doi.org/10.1164/rccm.9120-11ST.

Article  CAS  PubMed  PubMed Central  Google Scholar 

Edwards U, Rogall T, Blöcker H, Emde M, Böttger EC. Isolation and direct complete nucleotide determination of entire genes. Characterization of a gene coding for 16S ribosomal RNA. Nucleic Acids Res. 1989;17(19):7843–53. https://doi.org/10.1093/nar/17.19.7843.