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Agrawal G, Borody TJ, Aitken JM. Mapping Crohn's Disease Pathogenesis with Mycobacterium paratuberculosis: A Hijacking by a Stealth Pathogen. Dig Dis Sci 2024; 69:2289-2303. [PMID: 38896362 DOI: 10.1007/s10620-024-08508-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 05/21/2024] [Indexed: 06/21/2024]
Abstract
Mycobacterium avium ssp. paratuberculosis (MAP) has been implicated in the development of Crohn's disease (CD) for over a century. Similarities have been noted between the (histo)pathological presentation of MAP in ruminants, termed Johne's disease (JD), and appearances in humans with CD. Analyses of disease presentation and pathology suggest a multi-step process occurs that consists of MAP infection, dysbiosis of the gut microbiome, and dietary influences. Each step has a role in the disease development and requires a better understanding to implementing combination therapies, such as antibiotics, vaccination, faecal microbiota transplants (FMT) and dietary plans. To optimise responses, each must be tailored directly to the activity of MAP, otherwise therapies are open to interpretation without microbiological evidence that the organism is present and has been influenced. Microscopy and histopathology enables studies of the mycobacterium in situ and how the associated disease processes manifest in the patient e.g., granulomas, fissuring, etc. The challenge for researchers has been to prove the relationship between MAP and CD with available laboratory tests and methodologies, such as polymerase chain reaction (PCR), MAP-associated DNA sequences and bacteriological culture investigations. These have, so far, been inconclusive in revealing the relationship of MAP in patients with CD. Improved and accurate methods of detection will add to evidence for an infectious aetiology of CD. Specifically, if the bacterial pathogen can be isolated, identified and cultivated, then causal relationships to disease can be confirmed, especially if it is present in human gut tissue. This review discusses how MAP may cause the inflammation seen in CD by relating its known pathogenesis in cattle, and from examples of other mycobacterial infections in humans, and how this would impact upon the difficulties with diagnostic tests for the organism.
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Affiliation(s)
- Gaurav Agrawal
- Division of Diabetes & Nutritional Sciences, King's College London, Franklin-Wilkins Building, London, SE1 9NH, UK.
- , Sydney, Australia.
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Ottardi M, Lechner I, Wang J, Schmitt S, Schneeberger M, Schmid RM, Stephan R, Meylan M. Seroprevalence of Mycobacterium avium subsp. paratuberculosis in Swiss dairy herds and risk factors for a positive herd status and within-herd prevalence. Front Vet Sci 2024; 11:1409694. [PMID: 39005723 PMCID: PMC11242548 DOI: 10.3389/fvets.2024.1409694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2024] [Accepted: 06/18/2024] [Indexed: 07/16/2024] Open
Abstract
Introduction Bovine paratuberculosis (PTB) is a chronic enteric disease caused by Mycobacterium avium subsp. paratuberculosis (MAP). Control of PTB is important given its negative economic consequences and the potential zoonotic role of MAP in Crohn's disease in humans. Methods To determine the seroprevalence of MAP in Swiss dairy herds and to identify risk factors associated with seropositive herd status and high within-herd seroprevalence, 10,063 serum samples collected from cattle over 12 months of age in 171 Swiss dairy farms were analyzed using a commercial ELISA test. Eight herds were excluded due to non-interpretable ELISA results. Risk factors associated with seropositive herd status and high within-herd seroprevalence were investigated with regression models using results from a questionnaire on management practices possibly associated with the introduction or spread of MAP in the remaining 163 herds. Univariable logistic regression was performed, carrying forward for multivariable regression analysis when p < 0.2. Results The calculated between-herd true seroprevalence was 3.6% (95% CI, 0.96-8.4%). Due to the low within-herd seroprevalence, it was not possible to calculate the true seroprevalence at animal level; the apparent within-herd seroprevalence ranged from 2.3 to 5.5% with a median of 3.6% in nine positive farms. Herd size (p = 0.037) and the common grazing of lactating cows with cows from other herds (p = 0.014) were associated with seropositive herd status, while heifers sharing alpine pasture with dairy cattle from other herds were associated with a decreased probability of the herd to test seropositive (p = 0.042). Reliable identification of significant risk factors associated with MAP spread and high seroprevalence of PTB within seropositive herds was not possible due to low observed seroprevalence within herds and low sensitivity of the ELISA test. Discussion These results highlight the limitation of serology for MAP diagnosis in small herds with low infection prevalence.
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Affiliation(s)
- Martina Ottardi
- Clinic for Ruminants, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | | | | | - Sarah Schmitt
- Institute for Food Safety and Hygiene, Section of Veterinary Bacteriology, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland
| | - Marianne Schneeberger
- Institute for Food Safety and Hygiene, Section of Veterinary Bacteriology, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland
| | | | - Roger Stephan
- Institute for Food Safety and Hygiene, Section of Veterinary Bacteriology, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland
| | - Mireille Meylan
- Clinic for Ruminants, Vetsuisse Faculty, University of Bern, Bern, Switzerland
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Duda HC, von Toerne C, Korbonits L, Didier A, Scholz AM, Märtlbauer E, Hauck SM, Deeg CA. Cathepsin S Is More Abundant in Serum of Mycobacterium avium subsp. paratuberculosis-Infected Dairy Cows. Metabolites 2024; 14:215. [PMID: 38668343 PMCID: PMC11051907 DOI: 10.3390/metabo14040215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2024] [Revised: 04/05/2024] [Accepted: 04/09/2024] [Indexed: 04/28/2024] Open
Abstract
Mycobacterium avium subsp. paratuberculosis (MAP) is the causative agent of bovine paratuberculosis, a chronic granulomatous enteritis leading to economic losses and posing a risk to human health due to its zoonotic potential. The pathogen cannot reliably be detected by standard methods, and immunological procedures during the infection are not well understood. Therefore, the aim of our study was to explore host-pathogen interactions in MAP-infected dairy cows and to improve diagnostic tests. Serum proteomics analysis using quantitative label-free LC-MS/MS revealed 60 differentially abundant proteins in MAP-infected dairy cows compared to healthy controls from the same infected herd and 90 differentially abundant proteins in comparison to another control group from an uninfected herd. Pathway enrichment analysis provided new insights into the immune response to MAP and susceptibility to the infection. Furthermore, we found a higher abundance of Cathepsin S (CTSS) in the serum of MAP-infected dairy cows, which is involved in multiple enriched pathways associated with the immune system. Confirmed with Western blotting, we identified CTSS as a potential biomarker for bovine paratuberculosis. This study enabled a better understanding of procedures in the host-pathogen response to MAP and improved detection of paratuberculosis-diseased cattle.
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Affiliation(s)
- Heidi C. Duda
- Chair of Physiology, Department of Veterinary Sciences, Ludwig Maximilian University of Munich, D-82152 Martinsried, Germany
| | - Christine von Toerne
- Metabolomics and Proteomics Core, Helmholtz Center Munich, German Research Center for Environmental Health, D-85763 Neuherberg, Germany (S.M.H.)
| | - Lucia Korbonits
- Chair of Physiology, Department of Veterinary Sciences, Ludwig Maximilian University of Munich, D-82152 Martinsried, Germany
| | - Andrea Didier
- Chair of Hygiene and Technology of Milk, Department of Veterinary Sciences, Ludwig Maximilian University of Munich, D-85764 Oberschleißheim, Germany; (A.D.)
| | - Armin M. Scholz
- Livestock Center of the Faculty of Veterinary Medicine, Ludwig Maximilian University of Munich, D-85764 Oberschleißheim, Germany;
| | - Erwin Märtlbauer
- Chair of Hygiene and Technology of Milk, Department of Veterinary Sciences, Ludwig Maximilian University of Munich, D-85764 Oberschleißheim, Germany; (A.D.)
| | - Stefanie M. Hauck
- Metabolomics and Proteomics Core, Helmholtz Center Munich, German Research Center for Environmental Health, D-85763 Neuherberg, Germany (S.M.H.)
| | - Cornelia A. Deeg
- Chair of Physiology, Department of Veterinary Sciences, Ludwig Maximilian University of Munich, D-82152 Martinsried, Germany
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Aitken JM, Aitken JE, Agrawal G. Mycobacterium avium ssp. paratuberculosis and Crohn's Disease-Diagnostic Microbiological Investigations Can Inform New Therapeutic Approaches. Antibiotics (Basel) 2024; 13:158. [PMID: 38391544 PMCID: PMC10886072 DOI: 10.3390/antibiotics13020158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 01/24/2024] [Accepted: 02/03/2024] [Indexed: 02/24/2024] Open
Abstract
Mycobacterium avium ssp. paratuberculosis (MAP) is the cause of Johne's disease (JD), which is a chronic infectious gastrointestinal disease of ruminants and is often fatal. In humans, MAP has been associated with Crohn's disease (CD) for over a century, without conclusive evidence of pathogenicity. Numerous researchers have contributed to the subject, but there is still a need for evidence of the causation of CD by MAP. An infectious aetiology in CD that is attributable to MAP can only be proven by bacteriological investigations. There is an urgency in resolving this question due to the rising global incidence rates of CD. Recent papers have indicated the "therapeutic ceiling" may be close in the development of new biologics. Clinical trial outcomes have demonstrated mild or inconsistent improvements in therapeutic interventions over the last decades when compared with placebo. The necessity to revisit therapeutic options for CD is becoming more urgent and a renewed focus on causation is essential for progress in identifying new treatment options. This manuscript discusses newer interventions, such as vaccination, FMT, dietary remediation and gut microbiome regulation, that will become more relevant as existing therapeutic options expire. Revisiting the MAP theory as a potential infectious cause of CD, rather than the prevailing concept of an "aberrant immune response" will require expanding the current therapeutic programme to include potential new alternatives, and combinations of existing treatments. To advance research on MAP in humans, it is essential for microbiologists and medical scientists to microscopically detect CWDM and to biologically amplify the growth by directed culture.
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Affiliation(s)
- John M Aitken
- Otakaro Pathways Ltd., Innovation Park, Christchurch 7675, New Zealand
| | - Jack E Aitken
- Otakaro Pathways Ltd., Innovation Park, Christchurch 7675, New Zealand
| | - Gaurav Agrawal
- Division of Diabetes & Nutritional Sciences, Franklin-Wilkins Building, King's College London, London SE1 9NH, UK
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Alhendi A, Naser SA. The dual role of interleukin-6 in Crohn's disease pathophysiology. Front Immunol 2023; 14:1295230. [PMID: 38106420 PMCID: PMC10722226 DOI: 10.3389/fimmu.2023.1295230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 11/14/2023] [Indexed: 12/19/2023] Open
Abstract
Interleukin-6 (IL-6) is a key mediator cytokine of the immune response as well as a regulator of many physiological and pathological processes. In Crohn's disease (CD), cytokine imbalance rules the intestinal microenvironment and leads to chronic inflammation of the gut. Pro-inflammatory cytokines are generally upregulated in inflammatory bowel disease (IBD) including TNFα and IL-6. Consequently, drugs that target these cytokines have been long sought and approved. Despite the short-term success in treating CD patients with anti-TNFα, many patients stopped responding to treatment, which made IL-6 an alternative target to alleviate inflammation in these patients. IL-6 has long been approached as part of the therapeutic strategies to treat CD and other inflammatory disorders. Clinical trials of CD patients have targeted IL-6 signaling in different mechanisms: blocking IL-6, neutralizing IL-6 receptor (IL-6R), or trapping the soluble IL-6/IL-6R complex. These trials have faced challenges and side effects in patients with gastrointestinal perforations and ulcers, for example, all of which highlight the dual role of IL-6 during intestinal inflammation and the need for this cytokine for intestinal tissue integrity. IL-6 is involved in a complex of upstream regulators and downstream signaling cascades and maintaining a physiological level of IL-6 in the blood and in the intestine is key for achieving health and homeostasis. In this review, we describe IL-6 biology and signaling and its involvement in intestinal health and inflammation. We also discuss the current strategies for targeting IL-6 pathways in CD patients, as well as molecular regulators representing potential therapeutic targets for IL-6 attenuation.
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Affiliation(s)
- Ala' Alhendi
- Division of Molecular Microbiology, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, United States
| | - Saleh A Naser
- Division of Molecular Microbiology, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, United States
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