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.

[Neuropsychiatric symptomatology in post-COVID syndrome. Intervention proposal and referral from primary care]. / Sintomatología neuropsiquiátrica en el síndrome post-COVID. Propuesta de manejo y derivación desde atención primaria.

SARS-CoV-2 infection is a multiorgan disease with a wide spectrum of clinical manifestations, including neurological and psychiatric, which are expressed in all stages of the disease and often has long-term symptoms, called post-COVID syndrome. Among the neuropsychiatric symptoms derived from this syndrome, in this article we focus on headache, cognitive impairment, taste and smell alterations, depression, anxiety and sleep disorders. Intervention algorithms for these symptoms in primary care establishing criteria for referral to specialized care are proposed.

[Mild encephalitis/encephalopathy syndrome with reversible splenial lesion associated with intraventricular bleeding secondary to cavernoma. Findings from the magnetic resonance brain scan]. / Síndrome de encefalitis/encefalopatía leve con lesión del esplenio reversible asociado a sangrado intraventricular secundario a cavernoma. Hallazgos en la resonancia magnética cerebral.

TITLE: Síndrome de encefalitis/encefalopatía leve con lesión del esplenio reversible asociado a sangrado intraventricular secundario a cavernoma. Hallazgos en la resonancia magnética cerebral.

The influence of interferon ß-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 ß-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 ß-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 ß-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 ß-1b may result from the effect of the drug on gut microbiota. Longitudinal and functional studies are necessary to establish a causal relationship.

Role of the gut microbiota in the development of various neurological diseases. / Papel de la microbiota intestinal en el desarrollo de diferentes enfermedades neurológicas.

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 intestinal microbiota in the development of multiple sclerosis. / Papel de la microbiota intestinal en el desarrollo de la esclerosis múltiple.

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.