Immune responses against Helicobacter pylori-specific antigens differentiate relapsing remitting from secondary progressive multiple sclerosis

Helicobacter pylori infection and Parkinson's Disease: etiology, pathogenesis and levodopa bioavailability

Parkinson's disease (PD), a neurodegenerative disorder with an unknown etiology, is primarily characterized by the degeneration of dopamine (DA) neurons. The prevalence of PD has experienced a significant surge in recent years. The unidentified etiology poses limitations to the development of effective therapeutic interventions for this condition. Helicobacter pylori (H. pylori) infection has affected approximately half of the global population. Mounting evidences suggest that H. pylori infection plays an important role in PD through various mechanisms. The autotoxin produced by H. pylori induces pro-inflammatory cytokines release, thereby facilitating the occurrence of central inflammation that leads to neuronal damage. Simultaneously, H. pylori disrupts the equilibrium of gastrointestinal microbiota with an overgrowth of bacteria in the small intestinal known as small intestinal bacterial overgrowth (SIBO). This dysbiosis of the gut flora influences the central nervous system (CNS) through microbiome-gut-brain axis. Moreover, SIBO hampers levodopa absorption and affects its therapeutic efficacy in the treatment of PD. Also, H. pylori promotes the production of defensins to regulate the permeability of the blood-brain barrier, facilitating the entry of harmful factors into the CNS. In addition, H. pylori has been found to induce gastroparesis, resulting in a prolonged transit time for levodopa to reach the small intestine. H. pylori may exploit levodopa to facilitate its own growth and proliferation, or it can inflict damage to the gastrointestinal mucosa, leading to gastrointestinal ulcers and impeding levodopa absorption. Here, this review focused on the role of H. pylori infection in PD from etiology, pathogenesis to levodopa bioavailability.

Helicobacter pylori infection and risk of multiple sclerosis: An updated meta-analysis

BACKGROUND

There is considerable controversy around the question as to whether Helicobacter pylori (H. pylori) infection has a protective or causative role in the development of multiple sclerosis (MS). This study evaluated published information to assess the association between H. pylori infection and MS.

METHODS

We conducted a comprehensive systematic review of relevant observational studies in international databases. A random-effects model was used to calculate pooled odds ratio (OR) and 95% confidence interval (CI). I² statistic was used to assess the between-study heterogeneity. Subgroup and meta-regression analyses were applied to identify the source of heterogeneity.

RESULTS

In total, 22 studies (25 datasets) were eligible for the meta-analysis: 17 datasets had prevalence data and eight datasets had data on the mean titer of anti-H. pylori IgG. The pooled prevalence of H. pylori was 44.1% (908/2606) in the MS patients and 46.1% (1016/2200) in the controls, indicating a non-significant protective effect of H. pylori on MS (OR, 0.82; 95%CI, 0.58-1.17). In the subgroup analysis, studies that used ELISA yielded a significant protective association (OR, 0.59; 95%CI, 0.46-0.77), while a positive non-significant association (OR, 1.33; 95%CI, 0.83-2.15) was found from studies that used other serological methods; interestingly, a significant positive association (OR, 6.64; 95%CI, 2.40-13.76) was found from studies that used histological methods to detect H. pylori infection.

CONCLUSIONS

Our findings do not support the hypothesis that H. pylori infection represents a protective factor against the development of MS; however, the results varied depending on the diagnostic method(s). Particularly, a significant positive association was identified when studies introduced results based on histological examination, suggesting that active H. pylori infection might be a risk factor for development of MS. Thus, further studies are needed utilizing accurate diagnostic methods to elucidate the association between active H. pylori infection and MS.

Helicobacter pylori and unignorable extragastric diseases: Mechanism and implications

Considered as the most popular pathogen worldwide, Helicobacter pylori is intensively associated with diverse gastric diseases, including gastric ulcers, chronic progressive gastritis, and gastric cancer. Aside from its pathogenic effect on gastric diseases, growing evidences reveal that H. pylori may be related to numerous extragastric diseases. In this article, we reviewed recent studies and systematically elucidated that H. pylori may interfere with many biological processes outside the stomach and influence the occurrence of various extragastric diseases. Many epidemiological studies have indicated that H. pylori plays a pathogenic role in COVID-19, atherosclerosis, hyperemesis gravidarum and several other extragastric diseases, while the effect of H. pylori is currently under investigation in gastroesophageal reflux disease, asthma, and inflammatory bowel disease. Moreover, we also summarized the possible pathogenic mechanisms of H. pylori that may be related to chronic systemic inflammation and molecular mimicker. Taken together, this review provides a new perspective on the role of H. pylori in extragastric diseases and explores the possible mechanisms, which may help guide clinical treatment.

Update to the Treatment of Parkinson's Disease Based on the Gut-Brain Axis Mechanism

Gastrointestinal (GI) symptoms represented by constipation were significant non-motor symptoms of Parkinson’s disease (PD) and were considered early manifestations and aggravating factors of the disease. This paper reviewed the research progress of the mechanism of the gut-brain axis (GBA) in PD and discussed the roles of α-synuclein, gut microbiota, immune inflammation, neuroendocrine, mitochondrial autophagy, and environmental toxins in the mechanism of the GBA in PD. Treatment of PD based on the GBA theory has also been discussed, including (1) dietary therapy, such as probiotics, vitamin therapy, Mediterranean diet, and low-calorie diet, (2) exercise therapy, (3) drug therapy, including antibiotics; GI peptides; GI motility agents, and (4) fecal flora transplantation can improve the flora. (5) Vagotomy and appendectomy were associated but not recommended.

The trimebutine effect on Helicobacter pylori-related gastrointestinal tract and brain disorders: A hypothesis

The localization of bacterial components and/or metabolites in the central nervous system may elicit neuroinflammation and/or neurodegeneration. Helicobacter pylori (a non-commensal symbiotic gastrointestinal pathogen) infection and its related metabolic syndrome have been implicated in the pathogenesis of gastrointestinal tract and central nervous system disorders, thus medications affecting the nervous system - gastrointestinal tract may shape the potential of Helicobacter pylori infection to trigger these pathologies. Helicobacter pylori associated metabolic syndrome, by impairing gut motility and promoting bacterial overgrowth and translocation, might lead to brain pathologies. Trimebutine maleate is a prokinetic drug that hastens gastric emptying, by inducing the release of gastrointestinal agents such as motilin and gastrin. Likewise, it appears to protect against inflammatory signal pathways, involved in inflammatory disorders including brain pathologies. Trimebutine maleate also acts as an antimicrobial agent and exerts opioid agonist effect. This study aimed to investigate a hypothesis regarding the recent advances in exploring the potential role of gastrointestinal tract microbiota dysbiosis-related metabolic syndrome and Helicobacter pylori in the pathogenesis of gastrointestinal tract and brain diseases. We hereby proposed a possible neuroprotective role for trimebutine maleate by altering the dynamics of the gut-brain axis interaction, thus suggesting an additional effect of trimebutine maleate on Helicobacter pylori eradication regimens against these pathologies.

Helicobacter pylori infection: Beyond gastric manifestations

Helicobacter pylori (H. pylori) is a bacterium that infects more than a half of world’s population. Although it is mainly related to the development of gastroduodenal diseases, several studies have shown that such infection may also influence the development and severity of various extragastric diseases. According to the current evidence, whereas this bacterium is a risk factor for some of these manifestations, it might play a protective role in other pathological conditions. In that context, when considered the gastrointestinal tract, H. pylori positivity have been related to Inflammatory Bowel Disease, Gastroesophageal Reflux Disease, Non-Alcoholic Fatty Liver Disease, Hepatic Carcinoma, Cholelithiasis, and Cholecystitis. Moreover, lower serum levels of iron and vitamin B12 have been found in patients with H. pylori infection, leading to the emergence of anemias in a portion of them. With regards to neurological manifestations, a growing number of studies have associated that bacterium with multiple sclerosis, Alzheimer’s disease, Parkinson’s disease, and Guillain-Barré syndrome. Interestingly, the risk of developing cardiovascular disorders, such as atherosclerosis, is also influenced by the infection. Besides that, the H. pylori-associated inflammation may also lead to increased insulin resistance, leading to a higher risk of diabetes mellitus among infected individuals. Finally, the occurrence of dermatological and ophthalmic disorders have also been related to that microorganism. In this sense, this minireview aims to gather the main studies associating H. pylori infection with extragastric conditions, and also to explore the main mechanisms that may explain the role of H. pylori in those diseases.

Autoantibodies against specific nuclear antigens are present in psoriatic disease and are diminished by secukinumab

Anti-nuclear antibodies (ANA) are frequently detected in patients with psoriasis (Ps) and psoriatic arthritis (PsA), but their target autoantigens remain unknown. We assessed antibody (ab) reactivity against 23 known nuclear antigens in patients with Ps and PsA and assess the effects of secukinumab (anti-IL17A) treatment on ANA levels. A total of 201 patients, 101 with Ps and 100 with PsA, and 50 ANA-negative healthy controls (HCs) were tested for ANAs by a line immunoassay testing reactivity to 23 nuclear antigens. Ab reactivity to at least 1 antigen was found in 20.4% psoriatic disease patients (25.7% Ps and 15% PsA) compared to 8% HCs (p = ns), the most frequent being against dense fine speckled 70 (DFS70) (6.5%). In Ps and PsA patients with secukinumab-induced remission, anti-DFS70 and other antigen-specific autoantibodies were diminished over time. No decline was noted for IgG abs against antigens from pathogens such as cytomegalovirus, Epstein-Barr virus and Helicobacter pylori. Autoantibody decrease was associated with significant reduction of plasmablasts, follicular B and follicular T cells. In conclusion, one third of antigen-specific ANA patients with psoriatic disease recognize DFS70. Secukinumab decreases nuclear antigen autoreactivity, plasmablasts, follicular B and follicular T cells, highlighting a new mechanism of its action.

Antigen-specific humoral responses against Helicobacter pylori in patients with systemic sclerosis

Helicobacter pylori (Hp) is a likely trigger of systemic sclerosis (SSc), but systemic antigen-specific antibody (Ab) responses in a well-defined cohort of SSc patients have not been thoroughly assessed. Line immunoassay and immunoblotting testing Abs against 15 Hp antigens were performed in 91 SSc patients and 59 demographically matched healthy controls (HCs). Results were validated in an independent cohort of 35 SSc patients. Anti-Hp positivity was detected in 67% SSc patients vs 76.3% HCs. Among anti-Hp (+) individuals, anti-p67-FSH was less frequent in SSc than HCs (p = 0.016), whereas reactivity to the remaining 14 Hp antigens did not differ between patients and HCs. Anti-p67 Abs were less frequent in diffuse cutaneous SSc (dcSSc) compared with HCs (p = 0.018). Anti-p57 and anti-p33 Ab levels were lower in SSc vs HCs (p = 0.007 and p = 0.035, respectively). Anti-p57 and anti-p33 Ab levels were lower in limited cutaneous SSc (lcSSc) (p = 0.010) and dcSSc (p = 0.024), respectively, compared with HCs. Anti-p50 and anti-p17 Ab titers tended to be higher in dcSSc than in lcSSc. Sera from the independent SSc cohort showed comparable results. Anti-VacA Abs were more frequent in pulmonary arterial hypertension (p = 0.042), and anti-p30 Abs were more frequent in calcinosis (p = 0.007), whereas anti-VacA Ab levels were higher in lung fibrosis (p = 0.02). In conclusion, anti-Hp Abs are neither more frequent nor elevated in SSc compared with healthy population, the only exception being the higher frequency and levels of anti-VacA Abs in pulmonary hypertension and lung fibrosis, respectively. These results suggest that Hp is unlikely to be involved in the development of SSc.

Association of helicobacter pylori with multiple sclerosis: Protective or risk factor?

Background: Multiple sclerosis (MS) is a common autoimmune inflammatory disease in the central nervous system (CNS) without exact pathology. Environmental factors such as infections have a causal or protective role in MS. Helicobacter pylori (HP) is one of the infections in digestive diseases and previous studies reported controversial findings of this infection role in MS. So, we conducted this study to assess the frequency of HP infection in patients with MS in comparison to the healthy population. Methods: This cross-sectional study was undertaken between 2015 and 2019. 191 participants including 58 patients with clinically isolated syndrome (CIS), 57 patients with relapsing-remitting MS (RRMS), 39 patients with secondary progressive MS (SPMS), and 39 age- and sex-matched healthy controls (HCs) were tested for the presence of HP immunoglobulin G (IgG) and IgM antibodies (Abs) in their serum sample. Results: The frequency of HP IgG seropositivity in patients with SPMS was significantly higher than patients with CIS [Odds ratio (OR): 6.333, 95% confidence interval (CI): 2.522-15.906, P < 0.001], patients with RRMS (OR: 4.583, 95% CI: 1.842-11.407, P = 0.001), and HCs (OR: 8.485, 95% CI: 3.058-23.540, P < 0.001). We did not find a significant difference among other study groups regarding IgG seropositivity. No significant difference among groups regarding HP IgM seropositivity was evident. On univariate model, Expanded Disability Status Scale (EDSS) score (OR: 1.038, 95% CI: 1.038-1.460, P = 0.017) and SPMS (OR: 4.583, 95% CI: 1.842-11.407, P = 0.001) were predictor for HP IgG seropositivity. On multivariate model, only SPMS had higher risk for HP IgG seropositivity compared to RRMS (OR: 5.554, 95% CI: 1.327-23.253, P = 0.019). We did not find a significant association between clinical and demographic variables with HP IgM seropositivity. Conclusion: Based on our findings, progressive MS and HP infection may have association. Further longitudinal studies with large sample size are needed to determine the role of HP infection in MS.

Immune-mediated genesis of multiple sclerosis

Multiple sclerosis (MS) is widely acknowledged to be an autoimmune disease affecting the neuronal myelin structure of the CNS. Autoantigens recognized as the target of this autoimmune process are: myelin basal protein, anti-proteolipid protein, antimyelin-associated glycoprotein and antimyelin-based oligodendrocytic basic protein. Ample evidence supports the idea of a dysregulation of immunological tolerance towards self-antigens of neuronal myelin structure triggered by one or more viral or bacterial microbial agents in predisposed HLA gene subjects. Genetic predisposition to MS has been highlighted by numerous studies associating the disease to specific HLA haplotypes. Moreover, a wide range of evidence supports the fact that MS may be consequence of one or more viral or bacterial infections such as measles virus, EBV, HHV6, HZV, Chlamydia pneumoniae, Helicobacter Pylori, and other microbial agents. Microbiota elements also seems to have a role on the determinism of the disease as a pathogenic or protective factor. The autoimmune pathogenetic process could arise when a molecular mimicry between a foreign microbial antigen and an auto-antigen occurs in an HLA gene subject competent for that particular antigen. The antigen-presenting cells in this case would induce the activation of a specific Th clone causing a cross-reaction between a foreign antigen and an autoantigen resulting in an autoimmune response.

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A multifactorial ethiopathogenetic model based on immunomediation is a reliable hypothesis for multiple sclerosis.

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Evidence found in the scientific literature makes it possible to reconstruct this etiopathogenetic hypothesis for MS.

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HLA gene predisposition, correlation with infections, molecular mimicry and other immunological data are reported.

Brain atrophy in multiple sclerosis: mechanisms, clinical relevance and treatment options

Multiple sclerosis (MS) is an immune-mediated disease of the central nervous system characterized by focal or diffuse inflammation, demyelination, axonal loss and neurodegeneration. Brain atrophy can be seen in the earliest stages of MS, progresses faster compared to healthy adults, and is a reliable predictor of future physical and cognitive disability. In addition, it is widely accepted to be a valid, sensitive and reproducible measure of neurodegeneration in MS. Reducing the rate of brain atrophy has only recently been incorporated as a critical endpoint into the clinical trials of new or emerging disease modifying drugs (DMDs) in MS. With the advent of easily accessible neuroimaging softwares along with the accumulating evidence, clinicians may be able to use brain atrophy measures in their everyday clinical practice to monitor disease course and response to DMDs. In this review, we will describe the different mechanisms contributing to brain atrophy, their clinical relevance on disease presentation and course and the effect of current or emergent DMDs on brain atrophy and neuroprotection.

Altered Gut Microbiome and Intestinal Pathology in Parkinson's Disease

Parkinson's disease (PD) is a common neurodegenerative disorder arising from an interplay between genetic and environmental risk factors. Studies have suggested that the pathological hallmarks of intraneuronal α-synuclein aggregations may start from the olfactory bulb and the enteric nervous system of the gut and later propagate to the brain via the olfactory tract and the vagus nerve. This hypothesis correlates well with clinical symptoms, such as constipation, that may develop up to 20 years before the onset of PD motor symptoms. Recent interest in the gut-brain axis has led to vigorous research into the gastrointestinal pathology and gut microbiota changes in patients with PD. In this review, we provide current clinical and pathological evidence of gut involvement in PD by summarizing the changes in gut microbiota composition and gut inflammation associated with its pathogenesis.

Bacteria-Host Interactions in Multiple Sclerosis

Multiple sclerosis (MS) is caused by a complex interaction of genetic and environmental factors. Numerous causative factors have been identified that play a role in MS, including exposure to bacteria. Mycobacteria, Chlamydia pneumoniae, Helicobacter pylori, and other bacteria have been proposed as risk factors for MS with different mechanisms of action. Conversely, some pathogens may have a protective effect on its etiology. In terms of acquired immunity, molecular mimicry has been hypothesized as the mechanism by which bacterial structures such as DNA, the cell wall, and intracytoplasmic components can activate autoreactive T cells or produce autoantibodies in certain host genetic backgrounds of susceptible individuals. In innate immunity, Toll-like receptors play an essential role in combating invading bacteria, and their activation leads to the release of cytokines or chemokines that mediate effective adaptive immune responses. These receptors may also be involved in central nervous system autoimmunity, and their contribution depends on the infection site and on the pathogen. We have reviewed the current knowledge of the influence of bacteria on MS development, emphasizing the potential mechanisms of action by which bacteria affect MS initiation and/or progression.

H. pylori and Parkinson's disease: Meta-analyses including clinical severity

The exact etiology of Parkinson's disease (PD) remains unclear. Some evidence supports Helicobacter pylori infection as a trigger or driving event, but detection and eradication of H. pylori are not part of PD management. The aims of this case-control study and meta-analysis were to determine (i) the prevalence of H. pylori infection in PD patients, (ii) associations between H. pylori infection and clinical status, and (iii) differences in motor status in PD patients before and after H. pylori eradication. A literature search was performed using the PubMed database. The prevalence of H. pylori infection in PD, its association with the unified Parkinson's disease rating scale (UPDRS), and the association of H. pylori eradication therapy with the UPDRS-III score were determined by calculating the odds ratios (OR) and the standardized mean differences (SMD) with 95% confidence intervals (CI). Fixed- and random-effects models were applied. Ten studies were included in the first meta-analysis (5043 PD patients, 23,449 HCs); H. pylori infection prevalence was higher in PD patients than in HCs [OR (95% CI): 1.47 (1.27, 1.70), P_z<0.00001]. In seven studies reporting UPDRS scores (150 H. pylori infected, 228 non-infected PD patients), there was a significant association between H. pylori infection and mean UPDRS scores [SMD (95% CI): 0.33 (0.12, 0.54), P_z = 0.003]. Regarding H. pylori eradication, in five studies (90 PD patients), there was a significant reduction in UPDRS-III scores after treatment [SMD (95% CI): 6.83 (2.29, 11.38), P_z = 0.003]. In conclusion, the present meta-analysis revealed a higher prevalence of H. pylori infection in PD patients suggesting that H. pylori may contribute to PD pathophysiology. In addition, the significantly lower UPDRS scores in non-infected PD patients and in patients after H. pylori eradication therapy demonstrate that the infection may deteriorate the clinical severity of the disease.

Helicobacter pylori and extragastric diseases

Many studies have been performed in the last year concerning the potential role of Helicobacter pylori in different extragastric diseases, reinforcing the idea that specific microorganisms may cause diseases even far from the primary site of infection. While the role of H. pylori on idiopathic thrombocytopenic purpura, sideropenic anemia, and vitamin B12 deficiency has been well established, there is a growing interest in other conditions, such as cardiovascular, neurologic, dermatologic, obstetric, immunologic, and metabolic diseases. Concerning neurologic diseases, there is a great interest in cognitive impairment and neurodegeneration. The aim of this review was to summarize the results of the most relevant studies published over the last year on this fascinating topic.

CpG Island Methylation Patterns in Relapsing-Remitting Multiple Sclerosis

DNA methylation may predispose to multiple sclerosis (MS), as aberrant methylation in the promoter regions across the genome seems to underlie several processes of MS. We have currently determined the methylation status of eight genes in relapsing-remitting MS patients. Methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) was used to determine the status of 31 CpG islands, located across eight genes, in 33 healthy individuals and 66 MS patients (33 in relapse and 33 in remission). The methylation levels in the examined sites ranged from 0 to 31%. Methylation positivity for RUNX3 and CDKN2A differed significantly between MS patients and healthy controls. Maximum methylation in RUNX3, CDKN2A, SOCS1, and NEUROG1 genes was significantly different between patients and controls. Roc curves demonstrated that the appropriate cut-offs to distinguish patients from healthy controls were 2% for RUNX3 (OR 3.316, CI 1.207-9.107, p = 0.024) and 3% for CDKN2A (OR 3.077, CI 1.281-7.39, p = 0.018). No difference in methylation was observed between patients in relapse and patients in remission, in any of the genes examined. Methylation patterns of RUNX3 and CDKN2A may be able to distinguish between MS patients and healthy controls, but not between MS patients in relapse and in remission. Graphical Abstract Methylation patterns of RUNX3 and CDKN2A may be able to discriminate healthy individuals from MS patients.