Helicobacter pylori infection as a protective factor against multiple sclerosis risk in females

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

Numerous studies have proposed that Helicobacter pylori infection may possess a protective effect in terms of future risk of multiple sclerosis (MS), however is poorly evidenced. We performed a systematic review and meta-analysis to obtain the pooled results regarding the prevalence of H. pylori infection in persons with multiple sclerosis (pwMS) and healthy controls. A comprehensive database search was performed in PubMed, Embase, and medRxiv for all relevant literature published from the inception of the databases until the August 1, 2022. The retrieved articles were first screened by title and abstract, followed by full-text screening based on the pre-established eligibility criteria. The risk of bias was assessed using the ROBINS-I tool. Data on the seroprevalence of H. pylori in pwMS and healthy controls was extracted, and a meta-analysis was performed in Review Manager Version 5.4.1. Sub-group analysis was performed in accordance with the geographical distribution (Eastern and Western countries) and the method of detection of H. pylori infection enzyme-linked-immunoassay (ELISA), Immunofluorescence, Immunochromatography). Furthermore, sensitivity analyses and publication bias were determined. The preliminary database search retrieved a total of 822 studies. Seventeen case-control studies with a total of 2721 pwMS and 2245 controls were included as a final sample size for the meta-analysis. The overall risk of bias was moderate. Overall, the rate of H. pylori infection in pwMS was not significantly different than in healthy controls (OR: 0.79 (95% CI = 0.58-1.08); I2 = 79%, p = 0.14). Subgroup analysis revealed that the rate of H. pylori infection among PwMS was not significant in both Eastern and Western countries (OR: 0.75 (95% CI = 0.52-1.08); I2 = 81%, p = 0.12). In contrast, data revealed that the prevalence of H. pylori infection in pwMS was significantly lower than that of control based on studies utilizing ELISA assays detection (OR: 0.71 (95% CI = 0.50-1.00); I2 = 81%, p = 0.05), while no significant difference was seen on studies using other assays than ELISA (OR: 1.19 (95% CI = 0.81-1.77); I2 = 0%, p = 0.38). Our findings of statistically indifferent prevalence of H. pylori infection as compared between pwMS and healthy controls suggested the absence of protective effect for risk of MS following H. pylori infection.

The Interplay between Helicobacter pylori and Gut Microbiota in Non-Gastrointestinal Disorders: A Special Focus on Atherosclerosis

The discovery of Helicobacter pylori (H. pylori) in the early 1980s by Nobel Prize winners in medicine Robin Warren and Barry Marshall led to a revolution in physiopathology and consequently in the treatment of peptic ulcer disease. Subsequently, H. pylori has also been linked to non-gastrointestinal diseases, such as autoimmune thrombocytopenia, acne rosacea, and Raynaud's syndrome. In addition, several studies have shown an association with cardiovascular disease and atherosclerosis. Our narrative review aims to investigate the connection between H. pylori infection, gut microbiota, and extra-gastric diseases, with a particular emphasis on atherosclerosis. We conducted an extensive search on PubMed, Google Scholar, and Scopus, using the keywords "H. pylori", "dysbiosis", "microbiota", "atherosclerosis", "cardiovascular disease" in the last ten years. Atherosclerosis is a complex condition in which the arteries thicken or harden due to plaque deposits in the inner lining of an artery and is associated with several cardiovascular diseases. Recent research has highlighted the role of the microbiota in the pathogenesis of this group of diseases. H. pylori is able to both directly influence the onset of atherosclerosis and negatively modulate the microbiota. H. pylori is an important factor in promoting atherosclerosis. Progress is being made in understanding the underlying mechanisms, which could open the way to interesting new therapeutic perspectives.

The interplay between Epstein-Barr virus DNA and gut microbiota in the development of arthritis in a mouse model

Epstein-Barr virus (EBV) DNA may influence the development of autoimmune diseases by increasing the production of proinflammatory cytokines. Such cytokines have been associated with inducing the dysbiosis of colonic microbiota, which, in turn, is a risk factor for autoimmune diseases such as rheumatoid arthritis (RA). Therefore, we investigated the role that EBV DNA may play in modulating the intestinal microbiota and consequent exacerbation of arthritis in a mouse model. Mice were treated with collagen (arthritis-inducing agent), EBV DNA and collagen, EBV DNA, or water. Fecal samples were collected from arthritic and control mice, and 16S rRNA sequencing was performed to determine the effect of EBV DNA on the composition of colonic microbiota. EBV DNA causes a change in the alpha diversity of the microbiota resulting in an increased Chao1 microbial richness and decreased Shannon diversity index in the RA mouse model. In addition, the abundance of particular genera/genus clusters was significantly altered among the various groups, with the EBV DNA-exacerbated arthritic group having the highest number of altered genera/genus cluster abundances. This group also had the highest number of cells co-expressing IL-17A, FOXP3, and IFNγ in the colons. Antimicrobial-cleared mice transplanted with fecal samples from EBV DNA-exacerbated arthritic mice showed a higher incidence and enhanced severity of RA compared to those transplanted with fecal samples from water or collagen-treated mice. IMPORTANCE Epstein-Barr virus (EBV) DNA alters the composition and diversity of the gut microbiota in a rheumatoid arthritis (RA) mouse model. These induced changes are associated with enhanced severity of symptoms. This better understanding of the various factors involved in the development of RA will possibly help in creating individualized treatments for RA patients including target mediators triggered by viral DNA. Given that a large swathe of the population harbors EBV, a significant proportion of subjects with arthritis may benefit from possible approaches that target EBV or mediators triggered by this virus.

Helicobacter pylori infection may influence prevalence and disease course in myelin oligodendrocyte glycoprotein antibody associated disorder (MOGAD) similar to MS but not AQP4-IgG associated NMOSD

Background

Helicobacter pylori (Hp) persists after colonizing the gut in childhood, and potentially regulates host immune system through this process. Earlier studies have shown that Hp infection in childhood, may protect against MS in later life. Such an association was not seen with AQP4-IgG positive NMOSD, while the association with MOGAD is unclear.

Objective

To evaluate frequency of Hp IgG among patients with MOGAD, MS, NMOSD and matched controls and its effect on disease course. To ascertain whether childhood socio economic factors were linked to prevalence of Hp infection.

Methods

In all, 99 patients diagnosed to have MOGAD, 99 AQP4 IgG+ NMOSD, 254MS and 243 matched controls were included. Patient demographics, diagnosis, age at disease onset, duration and the last recorded expanded disability status scale (EDSS) were obtained from our records. Socioeconomic and educational status was queried using a previously validated questionnaire. Serum HpIgG was detected using ELISA kits (Vircell, Spain).

Result

Frequency of Hp IgG was significantly lower among MOGAD (28.3% vs 44%, p-0.007) and MS (21.2% vs 44%, p-0.0001) but not AQP4-IgG+ NMOSD patients (42.4% vs 44%, p-0.78) when compared to controls. Frequency of Hp IgG in MOGAD & MS patients combined (MOGAD-MS) was significantly lower than those with NMOSD (23.2% vs 42.4%, p- 0.0001). Seropositive patients with MOGAD- MS were older (p-0.001. OR -1.04, 95% CI- 1.01- 1.06) and had longer disease duration (p- 0.04, OR- 1.04, 95% CI- 1.002- 1.08) at time of testing. Educational status was lower among parents/caregivers of this study cohort (p- 0.001, OR -2.34, 95% CI- 1.48-3.69) who were Hp IgG+.

Conclusions

In developing countries Hp infection may be a significant environmental factor related to autoimmune demyelinating CNS disease. Our preliminary data suggests that Hp may exert a differential influence - a largely protective role for MS-MOGAD but not NMOSD and may influence disease onset and course. This differential response maybe related to immuno-pathological similarities between MOGAD and MS in contrast to NMOSD. Our study further underscores the role of Hp as a surrogate marker for poor gut hygiene in childhood and its association with later onset of autoimmune diseases.

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.

Epidemiology of Helicobacter pylori in Australia: a scoping review

Background

Helicobacter pylori (H. pylori), a bacterium implicated in the development of peptic ulcer and gastric cancer, is estimated to infect around half the world's population. Its prevalence in Australia is unclear. This scoping review aimed to evaluate all Australian literature providing estimates of the prevalence of H. pylori.

Methods

Australian studies examining H. pylori prevalence from 1982 onwards were eligible for inclusion. Medline, Embase and Scopus databases, and grey literature sources, were searched. Two independent reviewers undertook a two-stage screening process. Data were extracted by two independent reviewers using a pre-specified template.

Results

Of 444 identified studies, 75 were included in the review. H. pylori prevalence in Australian population-based studies (n = 8) ranged from 38.0% in 1991 to 15.1% in 2002; however, estimated prevalence across all non-clinical population studies in diverse sub-groups (n = 29) has varied dramatically. Decreased prevalence has been more marked in populations with gastrointestinal symptoms and conditions compared to non-clinical populations. Data on H. pyloriprevalence in vulnerable populations are lacking.

Conclusions

This is the first scoping review of Australian studies reporting H. pylori prevalence. A wide range of study designs, population groups, geographic regions, and diagnostic methods was included, involving data collected over a 50-year period (1969 to 2018). The summary of H. pylori prevalence estimates over time in this review points to a decrease in prevalence in Australia, particularly among populations with gastrointestinal symptoms and illnesses; however, it is unknown whether there is inequity in prevalence trends across vulnerable sub-groups of the Australian population. Future research and interventions supporting the health and wellbeing of vulnerable populations is required to ensure equitable health gains are made for all.

Helicobacter pylori antibodies and multiple sclerosis: a single-center study and a short review of the literature

Background

Multiple sclerosis is an immune-mediated disease which has been associated to a great variety of mechanisms that could influence its pathogenesis. Numerous reports in the medical literature suggest that Helicobacter pylori may be a mediator of the disease. However, it is unknown if there is any clear association between MS and HP.

Results

We studied 144 persons with multiple sclerosis prospectively enrolled in our hematopoietic stem cell transplantation program. In 144 persons, 14% patients were positive for IgG-HP whereas 86% were negative, 8.3% pwMS were IgM-HP positive while 91.6% pwMS were negative, 18% patients were positive and 82% negative for IgA-HP. Significantly lower concentrations of anti-HP IgG were found in RRMS in comparison with SPMS (− 28.5, 95% CI 4.3–52.7). While concentrations of anti-HP IgA were significantly lower in SPMS in comparison with RRMS (0.54, 95% CI 0.1–0.9). In a multivariate analysis, positivity rate of anti-HP IgG was found to be higher in SPMS patients (OR 4.7, 95% CI 1.1–19.6).

Conclusions

There was a negative correlation between the presence of anti-HP antibodies and MS. Further larger studies with specific laboratory testing methods are needed to discard or confirm the potential role of anti-HP antibodies as protective for MS.

Crosstalk of Microorganisms and Immune Responses in Autoimmune Neuroinflammation: A Focus on Regulatory T Cells

Regulatory T cells (Tregs) are the major determinant of peripheral immune tolerance. Many Treg subsets have been described, however thymus-derived and peripherally induced Tregs remain the most important subpopulations. In multiple sclerosis, a prototypical autoimmune disorder of the central nervous system, Treg dysfunction is a pathogenic hallmark. In contrast, induction of Treg proliferation and enhancement of their function are central immune evasion mechanisms of infectious pathogens. In accordance, Treg expansion is compartmentalized to tissues with high viral replication and prolonged in chronic infections. In friend retrovirus infection, Treg expansion is mainly based on excessive interleukin-2 production by infected effector T cells. Moreover, pathogens seem also to enhance Treg functions as shown in human immunodeficiency virus infection, where Tregs express higher levels of effector molecules such as cytotoxic T-lymphocyte-associated protein 4, CD39 and cAMP and show increased suppressive capacity. Thus, insights into the molecular mechanisms by which intracellular pathogens alter Treg functions might aid to find new therapeutic approaches to target central nervous system autoimmunity. In this review, we summarize the current knowledge of the role of pathogens for Treg function in the context of autoimmune neuroinflammation. We discuss the mechanistic implications for future therapies and provide an outlook for new research directions.

Helicobacter pylori Infection and Extragastric Diseases-A Focus on the Central Nervous System

Helicobacter pylori (H. pylori) is most known to cause a wide spectrum of gastrointestinal impairments; however, an increasing number of studies indicates that H. pylori infection might be involved in numerous extragastric diseases such as neurological, dermatological, hematologic, ocular, cardiovascular, metabolic, hepatobiliary, or even allergic diseases. In this review, we focused on the nervous system and aimed to summarize the findings regarding H. pylori infection and its involvement in the induction/progression of neurological disorders. Neurological impairments induced by H. pylori infection are primarily due to impairments in the gut-brain axis (GBA) and to an altered gut microbiota facilitated by H. pylori colonization. Currently, regarding a potential relationship between Helicobacter infection and neurological disorders, most of the studies are mainly focused on H. pylori.

Correlation of Dietary Intake and Helicobacter pylori Infection with Multiple Sclerosis, a Case-Control Study in Rafsanjan, Iran, 2017-18

Background: Multiple sclerosis (MS) is an autoimmune disease affecting the central nervous system. Some environmental factors, such as Helicobacter pylori infection (HPI), are likely to be considered a protective factor in MS. Dietary intake may provide exposure to or have protective effects for MS. The present study aimed to determine the relationship between serum anti-H. pylori IgG antibody (HPIA) level and dietary intake in patients with MS referred to the MS Clinic in Rafsanjan city, Iran.

Methods: The present case-control study was conducted on 97 patients with MS and 95 controls. The two groups had no significant difference in age and gender (p > 0.05). HPIA was checked, and the food frequency questionnaire was completed in both groups to measure nutritional intake. All data were analyzed by the SPSS 20 software using independent t-test, Chi-Square, Mann–Whitney U test, and correlation.

Results: The median serum HPIA level was significantly lower in MS cases than in controls. Furthermore, the median consumption of glutamic acid, arginine, serine, aspartic acid, alanine, proline, and caffeine was significantly lower in MS cases than in controls. A significant positive correlation was found between the levels of linoleic acid, lactose, Ca, molybdenum, galactose, leucine, and valine, and the level of HPIA in controls.

Conclusion: Our study results demonstrated that some dietary nutrients had correlations with MS and HPI. Therefore, professionals from multiple disciplines must find which foods contain these dietary nutrients in future studies.

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.

Infections, Vaccines and Autoimmunity: A Multiple Sclerosis Perspective

Background: Multiple sclerosis (MS) is a chronic neuroinflammatory and neurodegenerative disease that is associated with multiple environmental factors. Among suspected susceptibility events, studies have questioned the potential role of overt viral and bacterial infections, including the Epstein Bar virus (EBV) and human endogenous retroviruses (HERV). Furthermore, the fast development of immunomodulatory therapies further questions the efficacy of the standard immunization policies in MS patients. Topics reviewed: This narrative review will discuss the potential interplay between viral and bacterial infections and their treatment on MS susceptibility and disease progression. In addition, the review specifically discusses the interactions between MS pathophysiology and vaccination for hepatitis B, influenza, human papillomavirus, diphtheria, pertussis, and tetanus (DTP), and Bacillus Calmette-Guerin (BCG). Data regarding potential interaction between MS disease modifying treatment (DMT) and vaccine effectiveness is also reviewed. Moreover, HERV-targeted therapies such as GNbAC1 (temelimab), EBV-based vaccines for treatment of MS, and the current state regarding the development of T-cell and DNA vaccination are discussed. Lastly, a reviewing commentary on the recent 2019 American Academy of Neurology (AAN) practice recommendations regarding immunization and vaccine-preventable infections in the settings of MS is provided. Conclusion: There is currently no sufficient evidence to support associations between standard vaccination policies and increased risk of MS. MS patients treated with immunomodulatory therapies may have a lower benefit from viral and bacterial vaccination. Despite their historical underperformance, new efforts in creating MS-based vaccines are currently ongoing. MS vaccination programs follow the set back and slow recovery which is widely seen in other fields of medicine.

The most influential articles in Helicobacter pylori research: A bibliometric analysis

OBJECTIVE

The number of articles that researchers must be familiar with is increasing, along with the importance of selective searching and summarization. This study aimed to assess and characterize the most influential articles in Helicobacter pylori research.

METHODS

We performed a search of the top-100 cited articles using the Web of Science Core Collection (WoSCC) and Google Scholar from their inception to 2018. The top-100 Altmetric Attention Score (AAS) articles based on online media mentions were also searched using the term H pylori. Each article was evaluated for the following characteristics: citation number, title, journal, publication year, and authorship.

RESULTS

The citation number for the top-100 WoSCC articles ranged from 44 to 367. Gut published the largest number of articles (11%). In the top-100 Google Scholar articles, Lancet had the largest number of articles (13%); however, among the top-1000 cited articles published after 2012, Helicobacter published the largest number (46%). The largest number of top-100 AAS articles was published by PLOS Pathogens (6%). PubMed Central articles' citations in WoSCC or Google Scholar showed significant correlation with those from each metric; however, AAS showed no correlation. The proportion of basic research was 36%-37% in top-cited articles; but, 52% in the top-100 AAS articles. No time trend in the number of publications or citations of basic/clinical research in the top-100 bibliometrics was found. "Meta-analysis/systematic review," "gastric cancer," "eradication," and "association" were the most influential title words.

CONCLUSION

This study presents a detailed list of top-100 articles, journals, authors, and topic title words.

Why monkeys do not get multiple sclerosis (spontaneously): An evolutionary approach

The goal of this review is to apply an evolutionary lens to understanding the origins of multiple sclerosis (MS), integrating three broad observations. First, only humans are known to develop MS spontaneously. Second, humans have evolved large brains, with characteristically large amounts of metabolically costly myelin. This myelin is generated over long periods of neurologic development—and peak MS onset coincides with the end of myelination. Third, over the past century there has been a disproportionate increase in the rate of MS in young women of childbearing age, paralleling increasing westernization and urbanization, indicating sexually specific susceptibility in response to changing exposures. From these three observations about MS, a life history approach leads us to hypothesize that MS arises in humans from disruption of the normal homeostatic mechanisms of myelin production and maintenance, during our uniquely long myelination period. This review will highlight under-explored areas of homeostasis in brain development, that are likely to shed new light on the origins of MS and to raise further questions about the interactions between our ancestral genes and modern environments.

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

To assess whether Helicobacter pylori (Hp) antibody (ab) reactivity against individual Hp antigens is pathogenetically relevant to multiple sclerosis (MS), we systematically investigated prevalence and clinical significance of abs against 14 immunodominant and subdominant Hp antigens by ELISA and immunoblotting in 139 consecutive MS patients with relapsing-remitting (RRMS, n = 102) or secondary progressive (SPMS, n = 37). Sera from 39 patients with Parkinson’s disease (PD), 21 with Alzheimer’s disease (ALZ) and 68 healthy controls (HCs), were also tested. Anti-flagellin (18.3%) and anti-p41 (25.0%) abs in MS were less frequent than in HCs (39.4%, 48.5%, respectively). Abs against 5 of the 14 antigens were less frequent in RRMS than HCs, including p41, p54-flagellin, p29-UreA, p67-FSH, and p120-CagA. Anti-VacA abs were more frequent in SPMS than in HCs (42.1 vs 12.1%, p = 0.019). Anti-p54, anti-p29-UreA and anti-p26 correlated with extended disability status scale (EDSS) (p = 0.017, p = 0.005, p = 0.002, respectively). Anti-p26 and anti-p17 correlated with the number of relapses (p = 0.037 and p = 0.047, respectively). This is the first comprehensive analysis of ab reactivities against most Hp antigens in MS patients. Ab responses differ between MS and HCs and between RRMS and SPMS, being more prevalent in SPMS than RRMS, thus suggesting an association between anti-Hp and the former type of MS.

Helicobacter pylori and gut microbiota in multiple sclerosis versus Alzheimer's disease: 10 pitfalls of microbiome studies

Alteration of microbiota has been associated with intestinal, inflammatory, and neurological diseases. Abundance of "good bacteria" such as Bifidobacterium, or their products have been generally believed to be beneficial for any diseases, while "bad bacteria" such as pathogenic Helicobacter pylori are assumed to be always detrimental for hosts. However, this is not the case when we compare and contrast the association of the gut microbiota with two neurological diseases, multiple sclerosis (MS) and Alzheimer's disease (AD). Following H. pylori infection, pro-inflammatory T helper (Th)1 and Th17 immune response are initially induced to eradicate bacteria. However, H. pylori evades the host immune response by inducing Th2 cells and regulatory T cells (Tregs) that produce anti-inflammatory interleukin (IL)-10. Suppression of anti-bacterial Th1/Th17 cells by Tregs may enhance gastric H. pylori propagation, followed by a cascade reaction involving vitamin B₁₂ and folic acid malabsorption, plasma homocysteine elevation, and reactive oxygen species induction. This can damage the blood-brain barrier (BBB), leading to accumulation of amyloid-β in the brain, a hallmark of AD. On the other hand, this suppression of pro-inflammatory Th1/Th17 responses to H. pylori has protective effects on the hosts, since it prevents uncontrolled gastritis as well as suppresses the induction of encephalitogenic Th1/Th17 cells, which can mediate neuroinflammation in MS. The above scenario may explain why chronic H. pylori infection is positively associated with AD, while it is negatively associated with MS. Lastly, we list "10 pitfalls of microbiota studies", which will be useful for evaluating and designing clinical and experimental microbiota studies.

Papel de las enfermedades infecciosas en el desarrollo de la esclerosis múltiple: evidencia científica

Introducción

La esclerosis múltiple (EM) es el trastorno inflamatorio más común del sistema nervioso central (SNC) y la causa principal de discapacidad neurológica en adultos jóvenes. Los factores ambientales e infecciosos han sido fuertemente asociados al incremento de la ocurrencia de la enfermedad, hasta más del doble, en los últimos 10 años. En este artículo de revisión se describen los principales hallazgos reportados sobre la relación entre ciertas infecciones virales y bacterianas con la aparición y progresión de la EM.

Métodos

Se realizó un plan metodológico de búsqueda de artículos científicos relacionados con infección y EM, mediante la búsqueda de artículos científicos, principalmente publicados en inglés, en las plataformas virtuales de Pubmed, Medline y Cochrane. Para la búsqueda se utilizaron como palabras claves (términos MeSH): «virus, bacteria, autoimmune disease of the nervous system, multiple sclerosis». Se eligieron artículos publicados en revistas indexadas durante los últimos 15 años.

Resultados

Estudios epidemiológicos sugieren que la EM tiene un componente etiológico infeccioso que origina un proceso inflamatorio que puede contribuir a la iniciación o exacerbación de la enfermedad. Particularmente, la infección viral y los eventos de desmielinización en el SNC puede deberse a la penetración de un virus como el virus Epstein-Barr (EBV), a través del torrente sanguíneo, específicamente hacia el SNC. Por otro lado, las infecciones bacterianas crónicas pueden causar procesos de desmielinización en el SNC que agravan la enfermedad de EM.

Conclusiones

Este estudio contribuye a aportar evidencia científica donde se demuestra la multicausalidad implicada en la ocurrencia de la EM. Aún falta desarrollar más estudios epidemiológicos que demuestren y comprueben la relación y la implicación de agentes virales y bacterianos en el origen, el desarrollo y la severidad de la enfermedad.

Innate immune regulation of autoimmunity in multiple sclerosis: Focus on the role of Toll-like receptor 2

Innate immunity relies on a set of germline-encoded receptors including Toll-like receptors (TLRs) that enable the host to discriminate between self and non-self. Multiple sclerosis (MS) is an autoimmune inflammatory demyelinating disease of the central nervous system (CNS). Infections are thought to play an important role in disease susceptibility. The role of innate immunity in MS has been recently appreciated. TLR2, a member of the TLR family, forms heterodimers with either TLR1 or TLR6 and detects a wide range of microbial as well as self-derived molecular structures. It may thus be important both in fighting infection and in activating autoimmunity. In this review, we discuss innate regulation of autoimmunity in MS with a focus on the role of TLR2 signaling.

Anti-hsp60 antibody responses based on Helicobacter pylori in patients with multiple sclerosis: (ir)Relevance to disease pathogenesis

In view of published data suggesting that Helicobacter pylori (Hp) is a trigger of multiple sclerosis (MS), we assessed anti-heat shock protein 60 (hsp60)Hp antibody reactivity in 129 MS patients and 48 demograpically-matched healthy controls (HCs). Anti-Hp antibodies by ELISA were more elevated in MS than HCs but did not differ between different MS phenotypes. All anti-Hp-positive MS sera, irrespectively of their clinical phenotype, were anti-anti-hsp60 positive. Anti-hsp60 Hp seropositivity correlated with age at disease onset. In conclusion, anti-hsp60 Hp antibodies are present in all anti-Hp positive MS patients, and their relevance to disease pathogenesis is questionable.

Influence of Helicobacter pylori infection on extra-gastric diseases

The discovery of Helicobacter pylori (H. pylori) colonization of the stomach and its pathogenic effects is a crucial landmark in modern gastroenterology. There have been many studies reporting that the natural history of many disorders of the upper gastrointestinal tract, such as chronic gastritis, peptic ulcer disease, gastric cancer and MALT lymphoma are linked with the presence of this bacterium. Moreover, H. pylori is often involved in the pathogenic processes of a variety of extra-gastric diseases, especially those characterized by persistent and low grade systemic inflammation. The proposed mechanisms ranging from the induction of a low grade inflammatory state to the occurrence of molecular mimicry mechanisms. This paper will review the results of the most important studies on the association of H. pylori infection with extra-gastric diseases, such as autoimmune, neoplastic, cardiovascular and other related disorders, as well as possible mechanisms implicated in the pathogenesis of these extra-gastric diseases.

Meta-analysis of association between Helicobacter pylori infection and multiple sclerosis

Despite recent research focus on the association between Helicobacter pylori (H. pylori) infection and multiple sclerosis (MS) there is no consensus about the findings. To obtain a more comprehensive estimate of the association we conducted a meta-analysis to determine the prevalence of H. pylori infection in MS patients and healthy controls. Pubmed and EMBASE were searched to identify eligible studies. Nine studies were selected for inclusion, involving 2806 cases (1553 patients with MS and 1253 controls). Overall, the prevalence of H. pylori infection in MS patients was lower than that in control groups (24.66% vs. 31.84%, OR=0.69, 95% CI: 0.57-0.83, P<0.0001). Subgroup analysis revealed that the levels of H.pylori infection among MS patients were lower than for control subjects in Western countries (11.90% vs. 16.08%, OR=0.63, 95% CI: 0.43-0.91, P=0.01), but were not statistically significant in Eastern countries (39.39% vs. 43.82%, OR=0.79, 95% CI: 0.55-1.14, P=0.20). Our data show that H. pylori infection and MS is negatively correlated, especially in Western countries. Whether H. pylori infection is a protective factor against MS risk should thus be addressed in large-scale and prospective studies.

Role of intestinal microbiota in the development of multiple sclerosis

INTRODUCTION

Multiple sclerosis (MS) is a demyelinating disease that affects young adults; in that age group, it represents the second leading cause of disability in our setting. Its precise aetiology has not been elucidated, but it is widely accepted to occur in genetically predisposed patients who are exposed to certain environmental factors. The discovery of the regulatory role played by intestinal microbiota in various autoimmune diseases has opened a new line of research in this field, which is discussed in this review.

DEVELOPMENT

We reviewed published studies on the role of the microbiota in the development of both MS and its animal model, experimental autoimmune encephalomyelitis (EAE). In mice, it has been shown that intestinal microorganisms regulate the polarisation of T helper cells from Th1-Th17 up to Th2, the function of regulatory T cells, and the activity of B cells; they participate in the pathogenesis of EAE and contribute to its prevention and treatment. In contrast, evidence in humans is still scarce and mainly based on case-control studies that point to the presence of differences in certain bacterial communities.

CONCLUSIONS

Multiple evidence points to the role of microbiota in EAE. Extrapolation of these results to MS is still in the early stages of research, and studies are needed to define which bacterial populations are associated with MS, the role they play in pathogenesis, and the therapeutic possibilities this knowledge offers us.

Extragastric Diseases and Helicobacter pylori

The extragastric manifestations of Helicobacter pylori infection still remain a very strong topic throughout the H. pylori world. Indeed, H. pylori may interfere with many biological processes, both inside and outside of the stomach, possibly influencing or determining the occurrence of many diseases outside of the stomach. While its role in idiopathic thrombocytopenic purpura and sideropenic anemia has already been recognized, emerging evidence suggests that H. pylori may increase the risk of acute coronary syndrome, contribute to insulin resistance and be associated with neurodegenerative, respiratory, and other miscellaneous disorders previously associated with other conditions. Different pathogenic mechanisms have been hypothesized, including the induction of a low-grade inflammatory state and the occurrence of molecular mimicry mechanisms. This review summarizes the results of the most relevant studies published on this topic in the last year.

Autonomic Dysregulation in Multiple Sclerosis

Multiple sclerosis (MS) is a chronic, progressive central neurological disease characterized by inflammation and demyelination. In patients with MS, dysregulation of the autonomic nervous system may present with various clinical symptoms including sweating abnormalities, urinary dysfunction, orthostatic dysregulation, gastrointestinal symptoms, and sexual dysfunction. These autonomic disturbances reduce the quality of life of affected patients and constitute a clinical challenge to the physician due to variability of clinical presentation and inconsistent data on diagnosis and treatment. Early diagnosis and initiation of individualized interdisciplinary and multimodal strategies is beneficial in the management of autonomic dysfunction in MS. This review summarizes the current literature on the most prevalent aspects of autonomic dysfunction in MS and provides reference to underlying pathophysiological mechanisms as well as means of diagnosis and treatment.

The gut microbiome in multiple sclerosis

OPINION STATEMENT

The gut microbiome is made up of a wide range of (chiefly) bacterial species that colonize the small and large intestine. The human gut microbiome contains a subset of thousands of bacterial species, with up to 10(14) total bacteria. Studies examining this bacterial content have shown wide variations in which species are present between individuals. The gut microbiome has been shown to have profound effects on the development and maintenance of immune system in both animal models and in humans. A growing body of evidence has implicated the human gut microbiome in a range of disorders, including obesity, inflammatory bowel diseases, and cardiovascular disease. Animal studies present compelling evidence that the gut microbiome plays a significant role in the progression of demyelinating disease, and that modulation of the microbiome can lead to either exacerbation or amelioration of symptoms. Differences in diet, vitamin D insufficiency, smoking, and alcohol use have all been implicated as risk factors in MS, and all have the ability to affect the composition of the gut microbiota. Preliminary clinical trials aimed at modulating the gut microbiota in MS patients are underway and may prove to be a promising and lower-risk treatment option in the future.