Role of the gut microbiota in the development of various neurological diseases

INTRODUCTION

In recent years, the scientific evidence supporting a relationship between the microbiota and various diseases has increased significantly; this trend has also been observed for neurological diseases. This has given rise to the concept of the gut-brain axis and the idea of a relationship between the gut microbiota and several neurological diseases whose aetiopathogenesis is yet to be clearly defined.

DEVELOPMENT

We review the role of the gut microbiota in the gut-brain axis and analyse those neurological diseases in which alterations in the gut microbiota have been described as a result of human studies: specifically, Parkinson's disease, Alzheimer disease, amyotrophic lateral sclerosis, neuromyelitis optica, and multiple sclerosis.

CONCLUSIONS

The body of evidence linking the gut microbiota to various neurological diseases has grown considerably. Several interesting studies show a relationship between the gut microbiota and Parkinson's disease, Alzheimer disease, neuromyelitis optica, and multiple sclerosis, whereas other controversial studies implicate it in amyotrophic lateral sclerosis. Many of these studies place considerable emphasis on modulation of inflammation, particularly by bacteria capable of producing short-chain fatty acids. Despite these encouraging results, many questions remain, and there is a need to demonstrate causality, determine the role of fungi or viruses, and research possible treatment through diet, probiotics, or faecal microbiota transplantation.

Role of the gut microbiota in the development of various neurological diseases

INTRODUCTION

In recent years, the scientific evidence supporting a relationship between the microbiota and various diseases has increased significantly; this trend has also been observed for neurological diseases. This has given rise to the concept of the gut-brain axis and the idea of a relationship between the gut microbiota and several neurological diseases whose aetiopathogenesis is yet to be clearly defined.

DEVELOPMENT

We review the role of the gut microbiota in the gut-brain axis and analyse those neurological diseases in which alterations in the gut microbiota have been described as a result of human studies: specifically, Parkinson's disease, Alzheimer disease, amyotrophic lateral sclerosis, neuromyelitis optica, and multiple sclerosis.

CONCLUSIONS

The body of evidence linking the gut microbiota to various neurological diseases has grown considerably. Several interesting studies show a relationship between the gut microbiota and Parkinson's disease, Alzheimer disease, neuromyelitis optica, and multiple sclerosis, whereas other controversial studies implicate it in amyotrophic lateral sclerosis. Many of these studies place considerable emphasis on modulation of inflammation, particularly by bacteria capable of producing short-chain fatty acids. Despite these encouraging results, many questions remain, and there is a need to demonstrate causality, determine the role of fungi or viruses, and research possible treatment through diet, probiotics, or faecal microbiota transplantation.

The influence of interferon β-1b on gut microbiota composition in patients with multiple sclerosis

INTRODUCTION

The association between gut microbiota and animal models of multiple sclerosis has been well established; however, studies in humans are scarce.

METHODS

We performed a descriptive, cross-sectional study comparing the relative composition of gut microbiota in 30 patients with multiple sclerosis (15 treated with interferon β-1b, 15 not receiving this treatment) and 14 healthy controls using next generation sequencing.

RESULTS

Patients with multiple sclerosis and controls showed differences in the proportion of Euryarchaeota, Firmicutes, Proteobacteria, Actinobacteria, and Lentisphaerae phyla and in 17 bacterial species. More specifically, we found significant differences in the proportion of Firmicutes, Actinobacteria, and Lentisphaerae and 6 bacteria species between controls and untreated patients; however, these differences disappeared when compared with treated patients. Untreated patients showed a significant reduction in the proportion of Prevotella copri compared to controls, while the bacteria was significantly more abundant in patients treated with interferon β-1b than in untreated patients, with levels resembling those observed in the healthy control group.

CONCLUSION

We observed differences in gut microbiota composition between patients with multiple sclerosis and controls, and between patients treated and not treated with interferon β-1b. In most cases, no differences were observed between treated patients and healthy controls, particularly for P. copri levels. This suggests that the clinical improvements observed in patients with multiple sclerosis receiving interferon β-1b may result from the effect of the drug on gut microbiota. Longitudinal and functional studies are necessary to establish a causal relationship.

Biomonitoring of Mycotoxins in Plasma of Patients with Alzheimer's and Parkinson's Disease

Exposure to environmental contaminants might play an important role in neurodegenerative disease pathogenesis, such as Parkinson´s disease (PD) and Alzheimer´s disease (AD). For the first time in Spain, the plasmatic levels of 19 mycotoxins from patients diagnosed with a neurodegenerative disease (44 PD and 24 AD) and from their healthy companions (25) from La Rioja region were analyzed. The studied mycotoxins were aflatoxins B1, B2, G1, G2 and M1, T-2 and HT-2, ochratoxins A (OTA) and B (OTB), zearalenone, sterigmatocystin (STER), nivalenol, deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, deepoxy-deoxynivalenol, neosolaniol, diacetoxyscirpenol and fusarenon-X. Samples were analyzed by LC-MS/MS before and after treatment with β-glucuronidase/arylsulfatase in order to detect potential metabolites. Only OTA, OTB and STER were detected in the samples. OTA was present before (77% of the samples) and after (89%) the enzymatic treatment, while OTB was only detectable before (13%). Statistically significant differences in OTA between healthy companions and patients were observed but the observed differences might seem more related to gender (OTA levels higher in men, p-value = 0.0014) than the disease itself. STER appeared only after enzymatic treatment (88%). Statistical analysis on STER, showed distributions always different between healthy controls and patients (patients’ group > controls, p-value < 0.0001). Surprisingly, STER levels weakly correlated positively with age in women (rho = 0.3384), while OTA correlation showed a decrease of levels with age especially in the men with PD (rho = −0.4643).

[Efficacy and safety of fingolimod in routine clinical practice in patients with relapsing-remitting multiple sclerosis in Spain: an intermediate analysis of the MS NEXT study]

INTRODUCTION

Fingolimod is a disease modifying therapies, which has showed clinical efficacy and an acceptable safety profile in clinical trials with relapsing-remitting multiple sclerosis (RRMS) patients.

AIM

To assess fingolimod effectiveness and safety in patients with RRMS in clinical practice.

PATIENTS AND METHODS

We present an interim analysis (July 2015) of MS NEXT, an observational, retrospective and multicenter study. 442 patients were included (mean age: 41 ± 9 years; median baseline EDSS: 3.0; 70% female; 284 previously treated with first-line disease modifying therapies, 139 with natalizumab and 19 without a previous treatment; mean fingolimod treatment duration: 25 ± 9 months) treated with fingolimod from November 2011 and with at least 12 months follow-up. 56 neurology-unit Spanish hospitals enrolled patients. Basal clinical and demographic data were recorded. Relapses, EDSS scores and radiological activity were recorded at baseline and annually. Adverse events were also recorded during the follow-up period.

RESULTS

After two years of follow-up: annual relapse rates decreased by 76%, the proportion of relapse-free patients was 67%, of disability progression-free patients confirmed at 3 months was 91%, of relapse and disability progression-free patients was 63%, of radiological activity-free patients was 50%, and the proportion of relapse, disability progression and radiological activity-free patients was 35%. Only 3.9% of patients discontinued fingolimod permanently during the first year of treatment.

CONCLUSIONS

In this interim analysis, most of patients treated with fingolimod in clinical practice had a controlled clinical disease activity, stable disability progression and high persistency.

The influence of interferon β-1b on gut microbiota composition in patients with multiple sclerosis

INTRODUCTION

The association between gut microbiota and animal models of multiple sclerosis has been well established; however, studies in humans are scarce.

METHODS

We performed a descriptive, cross-sectional study comparing the relative composition of gut microbiota in 30 patients with multiple sclerosis (15 treated with interferon β-1b, 15 not receiving this treatment) and 14 healthy controls using next generation sequencing.

RESULTS

Patients with multiple sclerosis and controls showed differences in the proportion of Euryarchaeota, Firmicutes, Proteobacteria, Actinobacteria, and Lentisphaerae phyla and in 17 bacterial species. More specifically, we found significant differences in the proportion of Firmicutes, Actinobacteria, and Lentisphaerae and 6 bacteria species between controls and untreated patients; however, these differences disappeared when compared with treated patients. Untreated patients showed a significant reduction in the proportion of Prevotella copri compared to controls, while the bacteria was significantly more abundant in patients treated with interferon β-1b than in untreated patients, with levels resembling those observed in the healthy control group.

CONCLUSION

We observed differences in gut microbiota composition between patients with multiple sclerosis and controls, and between patients treated and not treated with interferon β-1b. In most cases, no differences were observed between treated patients and healthy controls, particularly for P. copri levels. This suggests that the clinical improvements observed in patients with multiple sclerosis receiving interferon β-1b may result from the effect of the drug on gut microbiota. Longitudinal and functional studies are necessary to establish a causal relationship.

[Fingolimod: effectiveness and safety in routine clinical practice. An observational, retrospective, multi-centre study in Navarra, Gipuzkoa and La Rioja]

AIM

To evaluate the effectiveness and safety of fingolimod in clinical practice in Navarra, Gipuzkoa and La Rioja regions.

PATIENTS AND METHODS

We conducted a retrospective multi-centre study with recurrent multiple sclerosis patients treated with fingolimod, following the product data sheet. The following data were evaluated: annualised relapse rate (ARR), percentage of patients free from relapses, disability using the Expanded Disability Status Scale (EDSS) and the percentage of patients without gadolinium-enhancing lesions.

RESULTS

A total of 113 patients were treated with fingolimod: 6% were naive, and 58% and 35% were patients previously treated with an immunomodulator and natalizumab, respectively. Fingolimod lowered the ARR after the first (67%; 1 to 0.3; p < 0.0001) and second (89%; 1 to 0.1; p < 0.0001) years of treatment, and thus the number of patients free from relapses during the treatment increased. The baseline EDSS was 3 and after treatment with fingolimod was 2.5 in both years. The percentage of patients without gadolinium-enhancing lesions after the first year of treatment was 77%. Similar results were observed in naive patients and in those previously treated with an immunomodulator. In patients previously treated with natalizumab no changes were observed following the treatment.

CONCLUSIONS

The use of fingolimod in clinical practice showed an effectiveness similar to that observed in clinical trials. There were no changes in the ARR after changing from natalizumab, and only one patient presented a 'relapse' after withdrawal of natalizumab. Fingolimod acts like a safe drug, with scarce side effects and a low percentage of drop-outs.

[Intraparenchymal hematomas: specific features in children]

INTRODUCTION

Intraparenchymatous haemorrhages are rare in infancy, but their effects may be very harmful. The aetiology, clinical characteristics and prognosis regarding life and function are different from those in adults.

OBJECTIVE

We decided to analyze the characteristics of this pathology in children and compare them with those in adults.

MATERIAL AND METHODS

We reviewed the clinical histories of the patients under 13 years of age presenting with a spontaneous intraparenchymatous haemorrhage during a 10 year period.

RESULTS

The study group was made up of 10 patients, 5 boys and 5 girls, aged between 23 days and 11 years. In 7 patients the aetiology was a burst arteriovenous malformation; in one a serious liver disorder due to alpha-l-antitrypsin deficiency; bleeding from an undiagnosed tumour caused another case and no aetiology was found in a further case. Two patients died, 6 patients had residual neurological defects and in the other two there were no sequelae.

CONCLUSIONS

Intraparenchymatous haematomas in children have a high mortality (20%) and many sequelae. The figures are comparable with those for elderly persons aged over 70 and much greater than in the case of young adults. The commonest aetiology is an arteriovenous malformation, followed at a considerable distance by coagulopathies and tumours.

[Respiratory dyskinesia induced by veralipride]

We describe the case of a patient whose menopause syndrome was treated with veralipride. After four months of this treatment she started to have bucco-lingual movements and marked dyspnea which caused difficult, irregular breathing and severe thoracic discomfort. After the drug was stopped there was progressive improvement and disappearance of the symptoms described. When the patient was taking a neuroleptic drug (veralipride) she developed bucco-lingual dyskinesia, considered to be the commonest late dyskinesia, together with marked respiratory dyskinesia. The latter is a type of dyskinesia seldom described, probably because it is only detected when it is severe enough to cause functional effects. It may pass unnoticed when the disorder is only slight or moderate. In the literature there are few references to disorders of movement induced by this drug, especially when compared with other benzamides which are frequently involved. However, in its mode of action there is a beneficial antigonadotropin activity together with an antidopaminergic effect which explains why they may cause such a reaction.