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Li S, Zhao W, Xia L, Kong L, Yang L. How Long Will It Take to Launch an Effective Helicobacter pylori Vaccine for Humans? Infect Drug Resist 2023; 16:3787-3805. [PMID: 37342435 PMCID: PMC10278649 DOI: 10.2147/idr.s412361] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 06/02/2023] [Indexed: 06/22/2023] Open
Abstract
Helicobacter pylori infection often occurs in early childhood, and can last a lifetime if not treated with medication. H. pylori infection can also cause a variety of stomach diseases, which can only be treated with a combination of antibiotics. Combinations of antibiotics can cure H. pylori infection, but it is easy to relapse and develop drug resistance. Therefore, a vaccine is a promising strategy for prevention and therapy for the infection of H. pylori. After decades of research and development, there has been no appearance of any H. pylori vaccine reaching the market, unfortunately. This review summarizes the aspects of candidate antigens, immunoadjuvants, and delivery systems in the long journey of H. pylori vaccine research, and also introduces some clinical trials that have displayed encouraging or depressing results. Possible reasons for the inability of an H. pylori vaccine to be available over the counter are cautiously discussed and some propositions for the future of H. pylori vaccines are outlined.
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Affiliation(s)
- Songhui Li
- Jiangsu Key Laboratory of Bioactive Natural Product Research and State Key Laboratory of Natural Medicines, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, 210009People’s Republic of China
| | - Wenfeng Zhao
- Department of Biochemistry, School of Life Science and Technology, China Pharmaceutical University, Nanjing, 210009People’s Republic of China
| | - Lei Xia
- Bloomage Biotechnology Corporation Limited, Jinan, People’s Republic of China
| | - Lingyi Kong
- Jiangsu Key Laboratory of Bioactive Natural Product Research and State Key Laboratory of Natural Medicines, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, 210009People’s Republic of China
| | - Lei Yang
- Jiangsu Key Laboratory of Bioactive Natural Product Research and State Key Laboratory of Natural Medicines, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, 210009People’s Republic of China
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Coltart I, Tranah TH, Shawcross DL. Inflammation and hepatic encephalopathy. Arch Biochem Biophys 2013; 536:189-96. [PMID: 23583306 DOI: 10.1016/j.abb.2013.03.016] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 03/13/2013] [Accepted: 03/19/2013] [Indexed: 12/12/2022]
Abstract
Hepatic encephalopathy (HE) is a neuropsychiatric syndrome associated with both acute and chronic liver dysfunction, spanning a spectrum that ranges from mild neuropsychological disturbances to coma. The central role of ammonia in the pathogenesis of HE remains incontrovertible however, there is a robust evidence base indicating the important role of inflammation in exacerbating the neurological effects of HE. Inflammation can arise directly within the brain itself as a result of deranged nitrogen and energy homeostasis, with resultant neuronal, astrocyte and microglial dysfunction. Inflammation may also originate in the peripheral circulation and exert effects on the brain indirectly, via the release of pro-inflammatory mediators which directly signal to the brain via the vagus nerve. This review summarises the data that demonstrate the synergistic relationship of inflammation and ammonia that culminates in the manifestation of HE. Sterile inflammation arising from the inflamed or necrotic liver, circulating endotoxin arising from the gut (bacterial translocation) inducing immune dysfunction, and superimposed sepsis will be comprehensively discussed. Finally, this review will provide an overview of the existing and novel treatments on the horizon which can target the inflammatory response, and how they might translate into clinical practise as therapies in the prophylaxis and treatment of HE.
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Affiliation(s)
- Iona Coltart
- Institute of Liver Studies, King's College London School of Medicine at King's College Hospital, King's College Hospital, Denmark Hill, London SE5 9RS, United Kingdom
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Navarathna DHMLP, Lionakis MS, Lizak MJ, Munasinghe J, Nickerson KW, Roberts DD. Urea amidolyase (DUR1,2) contributes to virulence and kidney pathogenesis of Candida albicans. PLoS One 2012; 7:e48475. [PMID: 23144764 PMCID: PMC3483220 DOI: 10.1371/journal.pone.0048475] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 09/26/2012] [Indexed: 12/24/2022] Open
Abstract
The intracellular enzyme urea amidolyase (Dur1,2p) enables C. albicans to utilize urea as a sole nitrogen source. Because deletion of the DUR1,2 gene reduces survival of C. albicans co-cultured with a murine macrophage cell line, we investigated the role of Dur1,2p in pathogenesis using a mouse model of disseminated candidiasis. A dur1,2Δ/dur1,2Δ strain was significantly less virulent than the wild-type strain, showing significantly higher survival rate, better renal function, and decreased and less sustained fungal colonization in kidney and brain. Complementation of the mutant restored virulence. DUR1,2 deletion resulted in a milder host inflammatory reaction. Immunohistochemistry, flow cytometry, and magnetic resonance imaging showed decreased phagocytic infiltration into infected kidneys. Systemic cytokine levels of wild-type mice infected with the dur1,2 mutant showed a more balanced systemic pro-inflammatory cytokine response. Host gene expression and protein analysis in infected kidneys revealed parallel changes in the local immune response. Significant differences were observed in the kidney IL-1 inflammatory pathway, IL-15 signaling, MAP kinase signaling, and the alternative complement pathway. We conclude that Dur1,2p is important for kidney colonization during disseminated candidiasis and contributes to an unbalanced host inflammatory response and subsequent renal failure. Therefore, this Candida-specific enzyme may represent a useful drug target to protect the host from kidney damage associated with disseminated candidiasis.
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Affiliation(s)
- Dhammika H. M. L. P. Navarathna
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Michail S. Lionakis
- Fungal Pathogenesis Unit, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Martin J. Lizak
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Jeeva Munasinghe
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Kenneth W. Nickerson
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, United States of America
| | - David D. Roberts
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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Shawcross DL, Shabbir SS, Taylor NJ, Hughes RD. Ammonia and the neutrophil in the pathogenesis of hepatic encephalopathy in cirrhosis. Hepatology 2010; 51:1062-9. [PMID: 19890967 DOI: 10.1002/hep.23367] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Hepatic encephalopathy (HE) constitutes a neuropsychiatric syndrome which remains a major clinical problem in patients with cirrhosis. In the severest form of HE, cirrhotic patients may develop varying degrees of confusion and coma. Ammonia has been regarded as the key precipitating factor in HE, and astrocytes have been the most commonly affected cells neuropathologically. Although the evidence base supporting a pivotal role of ammonia is robust, in everyday clinical practice a consistent correlation between the concentration of ammonia in the blood and the manifest symptoms of HE is not observed. More recently the synergistic role of inflammation and infection in modulating the cerebral effects of ammonia has been shown to be important. Furthermore, it has been recognized that infection impairs brain function both in the presence and absence of liver disease. Thus it could be postulated that in the presence of ammonia, the brain is sensitized to a systemic inflammatory stimulus and is able to elicit an inflammatory response involving both proinflammatory and neurotransmitter pathways. Ammonia is not only directly toxic to astrocytes but induces neutrophil dysfunction with the release of reactive oxygen species, which contribute to oxidative stress and systemic inflammation. This may further exacerbate the cerebral effects of ammonia and potentially reduce the capacity of the neutrophil to fight microbial attack, thus inducing a vicious circle. This evidence supports the neutrophil in addition to ammonia as being culpable in the pathogenesis of HE, making the neutrophil a target for future anti-inflammatory therapeutic strategies in addition to ammonia lowering therapies.
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Affiliation(s)
- Debbie L Shawcross
- Institute of Liver Studies, King's College London School of Medicine at King's College Hospital, 3rd Floor Cheyne Wing, King's College Hospital, Denmark Hill, London SE5 9RS, UK.
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Shawcross DL, Wright GAK, Stadlbauer V, Hodges SJ, Davies NA, Wheeler-Jones C, Pitsillides AA, Jalan R. Ammonia impairs neutrophil phagocytic function in liver disease. Hepatology 2008; 48:1202-12. [PMID: 18697192 DOI: 10.1002/hep.22474] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
UNLABELLED Hyperammonemia is a feature of liver failure, which is associated with increased risk of infection. The aims of the present study were to determine in vitro, in rats fed an ammoniagenic diet and in patients with cirrhosis, whether induction of hyperammonemia results in neutrophil dysfunction. As hyperammonemia produces cell swelling, we explored the role of the osmoregulating, p38 mitogen-activated protein kinase (p38(MAPK)) pathway in mediating this neutrophil dysfunction. Neutrophils were isolated from blood of healthy volunteers and incubated with either 75 microM ammonia or phosphate-buffered saline. Both groups were studied under hyponatremic conditions and/or with the addition of p38(MAPK) modulators. Neutrophil phagocytosis was measured in naive rats and rats fed an ammoniagenic diet and in patients with stable cirrhosis given placebo (n = 8) or an amino acid solution inducing hyperammonemia (n = 8). Cell volume and phagocytosis was analyzed by fluorescent-activated cell sorting using fluorescein isothiocyanate-labeled E. coli. p38(MAPK) phosphorylation was measured by western blotting. In healthy neutrophils incubated with ammonia and in rats fed an ammoniagenic diet, neutrophils showed evidence of swelling, impaired phagocytosis, and increased spontaneous oxidative burst compared to controls. Phagocytosis was significantly impaired in patients with induced hyperammonemia compared to placebo. The effects of hyperammonemia and hyponatremia were synergistic. The p38(MAPK) intracellular signaling pathways were activated in healthy neutrophils exposed to ammonia in association with increased burst activity. Neutrophil phagocytic dysfunction was abrogated by the addition of a p38(MAPK) agonist. CONCLUSION Ammonia produces neutrophil swelling and impairs neutrophil phagocytosis. The p38(MAPK) intracellular signaling pathway has been shown to be important in mediating the ammonia-induced neutrophil dysfunction.
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Affiliation(s)
- Debbie L Shawcross
- Liver Failure Group, The University College London (UCL) Institute of Hepatology, Division of Medicine, University College London, London, UK
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Lee OJ, Lee EJ, Kim HJ. Correlations among gastric juice pH and ammonia, Helicobacter pylori infection and gastric mucosal histology. Korean J Intern Med 2004; 19:205-12. [PMID: 15683108 PMCID: PMC4531573 DOI: 10.3904/kjim.2004.19.4.205] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND To assess the relationships among gastric pH and ammonia level, H. pylori infection, and gastric mucosal histology, we determined the gastric juice pH and ammonia concentration in H. pylori gastritis. METHODS The pH levels and ammonia concentrations were determined in gastric juice collected from 143 patients with dyspepsia during an endoscopy and compared according to a H. pylori infection. We also looked for correlations between two chemical parameters, between each of these parameters and H. pylori density, and histology. RESULTS Gastric pH levels and ammonia concentrations were higher in 94 infected patients than in the uninfected (3.16 vs. 1.55, p = 0.0001; 5.58 +/- 2.69 vs. 2.00 +/- 1.49 mol/L, p = 0.0001). Among 28 patients who received eradication therapy, 19 (67.9%) were successful, and their gastric pH levels and ammonia concentrations were significantly lower than those in the eradication failure group (1.60 vs. 2.33, p = 0.007; 1.77 +/- 1.28 vs. 4.02 +/- 1.20 micromoL/L, p = 0.0001). Gastric pH was significantly associated with intragastric ammonia concentration (p = 0.025) and gastritis activity (p = 0.018). Gastric pH and the ammonia level were significantly correlated with each other (rs = 0.495, p < 0.01), and with H. pylori density (rs = 0.467; rs = 0.735, p < 0.01), gastritis severity (rs = 0.343; rs = 0.478, p < 0.01), and gastritis activity (rs=0.418; rs = 0.579, p < 0.01). CONCLUSION Gastric juice pH and ammonia concentration reflect well the status of a H. pylori infection, and significantly correlate with each other and with H. pylori density, gastritis severity and activity. These findings suggest that intragastric ammonia produced by H. pylori may have a partial role in an increased gastric juice pH, and has a pathogenic role in H. pylori gastritis.
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Affiliation(s)
- Ok-Jae Lee
- Department of Internal Medicine, Institute of Health Science, College of Medicine, Gyeong-Sang National University, Jinju, Korea.
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Hofman V, Ricci V, Mograbi B, Brest P, Luciano F, Boquet P, Rossi B, Auberger P, Hofman P. Helicobacter pylori lipopolysaccharide hinders polymorphonuclear leucocyte apoptosis. J Transl Med 2001; 81:375-84. [PMID: 11310830 DOI: 10.1038/labinvest.3780245] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
A prominent histologic feature of Helicobacter pylori infection is a dense infiltration of polymorphonuclear leukocytes (PMNL) in gastric mucosa. H. pylori lipopolysaccharide (LPS) has been recognized as a primary virulence factor evoking acute mucosal inflammatory reaction. Previous works have shown that H. pylori LPS immunologic activities are lower than those of enterobacterial LPS. However, the effect of H. pylori LPS on spontaneous PMNL apoptosis, and mechanisms by which this H. pylori LPS may promote PMNL survival remain to be established. In this study, we investigated, by both morphologic and biochemical approaches, the action of H. pylori LPS on PMNL apoptosis in vitro, using broth culture filtrates (BCF) of H. pylori strains with different genotypes. We found that BCF from H. pylori caused a significant delay in spontaneous PMNL apoptosis and this delay was independent of the VacA, cag pathogenicity island and urease status. We demonstrated that LPS in BCF is responsible for this effect because it was abrogated by the LPS antagonist B287 (a synthetic analog of Rhodobactersphaeroides lipid A). Moreover, BCF from H. pylori induced P42/44MAP kinase activation in PMNL. Similar results were obtained with BCF of an Escherichia coli strain. Taken together these data suggest that longer survival of PMNL induced by H. pylori LPS may increase gastric epithelium injury in H. pylori-associated diseases.
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Affiliation(s)
- V Hofman
- Laboratoire d'Anatomie-Pathologique, Faculté de Médecine, Nice, France
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Kearney DJ, Ritchie K, Peacock JS. Gastric-juice ammonia assay for diagnosis of Helicobacter pylori infection and the relationship of ammonia concentration to gastritis severity. Am J Gastroenterol 2000; 95:3399-403. [PMID: 11151868 DOI: 10.1111/j.1572-0241.2000.03351.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVES To determine the test characteristics of gastric-juice ammonia concentration as measured by an ion-selective electrode and a rapid ammonia detection device for the diagnosis of Helicobacter pylori infection and to assess the relationship between gastric-juice ammonia concentration and the severity of gastritis. METHODS Patients undergoing upper endoscopy had collection of gastric juice that was tested for ammonia using an ion-selective electrode and a rapid ammonia assay device that uses a pH-indicating membrane. A receiver operating characteristic curve was calculated for ammonia concentration. Severity of gastritis was graded using the Sydney classification (1) and correlated to gastric-juice ammonia concentration. Patients also underwent H. pylori testing by IgG serology, rapid urease testing, and histological special stain. Ammonia testing results were compared with a reference standard of two of three positive tests and with a second reference standard of a positive serology. RESULTS 73 patients underwent endoscopy and collection of gastric juice. The receiver operating characteristic curve indicated an optimal cutoff value of 5 mM, yielding a sensitivity of 67%, specificity of 93%, positive predictive value of 67%, and negative predictive value of 93% (compared with the combined reference standard). The rapid NH3-testing device yielded a sensitivity of 83%, specificity 63%, positive predictive value 31%, and negative predictive value 95%. The severity of neutrophilic (p = 0.001) and mononuclear cell (p = 0.003) infiltration were significantly correlated with gastric-juice ammonia concentration. CONCLUSIONS Measurement of gastric-juice ammonia concentration by ion-selective electrode or rapid detection device is a relatively insensitive and nonspecific means of H. pylori diagnosis. Gastritis severity increases with gastric-juice ammonia concentration.
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Affiliation(s)
- D J Kearney
- Department of Medicine, Seattle Veterans Administration Medical Center, Washington 98108, USA
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Kuwahara H, Miyamoto Y, Akaike T, Kubota T, Sawa T, Okamoto S, Maeda H. Helicobacter pylori urease suppresses bactericidal activity of peroxynitrite via carbon dioxide production. Infect Immun 2000; 68:4378-83. [PMID: 10899833 PMCID: PMC98327 DOI: 10.1128/iai.68.8.4378-4383.2000] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Helicobacter pylori can produce a persistent infection in the human stomach, where chronic and active inflammation, including the infiltration of phagocytes such as neutrophils and monocytes, is induced. H. pylori may have a defense system against the antimicrobial actions of phagocytes. We studied the defense mechanism of H. pylori against host-derived peroxynitrite (ONOO(-)), a bactericidal metabolite of nitric oxide, focusing on the role of H. pylori urease, which produces CO(2) and NH(3) from urea and is known to be an essential factor for colonization. The viability of H. pylori decreased in a time-dependent manner with continuous exposure to 1 microM ONOO(-), i.e., 0.2% of the initial bacteria remained after a 5-min treatment without urea. The bactericidal action of ONOO(-) against H. pylori was significantly attenuated by the addition of 10 mM urea, the substrate for urease, whereas ONOO(-)-induced killing of a urease-deficient mutant of H. pylori or Campylobacter jejuni, another microaerophilic bacterium lacking urease, was not affected by the addition of urea. Such a protective effect of urea was potentiated by supplementation with exogenous urease, and it was almost completely nullified by 10 microM flurofamide, a specific inhibitor of urease. The bactericidal action of ONOO(-) was also suppressed by the addition of 20 mM NaHCO(3) but not by the addition of 20 mM NH(3). In addition, the nitration of L-tyrosine of H. pylori after treatment with ONOO(-) was significantly reduced by the addition of urea or NaHCO(3), as assessed by high-performance liquid chromatography with electrochemical detection. These results suggest that H. pylori-associated urease functions to produce a potent ONOO(-) scavenger, CO(2)/HCO(3)(-), that defends the bacteria from ONOO(-) cytotoxicity. The protective effect of urease may thus facilitate sustained bacterial colonization in the infected gastric mucosa.
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Affiliation(s)
- H Kuwahara
- Department of Microbiology, Kumamoto University School of Medicine, 2-2-1 Honjo, Kumamoto 860-0811, Japan
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