Prevalence of Gastrointestinal Symptoms, Severity of Dysphagia, and Their Correlation with Severity of Amyotrophic Lateral Sclerosis in a Mexican Cohort

Contribution of CNS and extra-CNS infections to neurodegeneration: a narrative review

Central nervous system infections have been suggested as a possible cause for neurodegenerative diseases, particularly sporadic cases. They trigger neuroinflammation which is considered integrally involved in neurodegenerative processes. In this review, we will look at data linking a variety of viral, bacterial, fungal, and protozoan infections to Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, multiple sclerosis and unspecified dementia. This narrative review aims to bring together a broad range of data currently supporting the involvement of central nervous system infections in the development of neurodegenerative diseases. The idea that no single pathogen or pathogen group is responsible for neurodegenerative diseases will be discussed. Instead, we suggest that a wide range of susceptibility factors may make individuals differentially vulnerable to different infectious pathogens and subsequent pathologies.

Radiologically Inserted Gastrostomy Tube Placement Guided by the Assessment and Primary Palliative Care Provided by an Amyotrophic Lateral Sclerosis Multidisciplinary Clinic: A Single-Arm Retrospective Clinical Study

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease with a median survival of about 3 years. An ALS multidisciplinary team can provide primary palliative care and improve outcomes and quality of life for patients. Feeding tube insertion may be considered for patients with significant weight loss, or respiratory insufficiency. While radiologically inserted gastrostomy (RIG) tube placement may be an option, further studies are required to determine its best timing and appropriateness. This study's objectives were to evaluate the feasibility and outcomes of RIG tube placement in ALS patients over a 90-day follow-up period through the assessment and primary palliative care provided by the multidisciplinary team. This retrospective study reviewed the placement of 16 or 18 French RIG-tube without intubation or endoscopy for 36 ALS patients at a single center between April 2019 and December 2021. Measures included ALS Functional Rating Scale-Revised (ALSFRS-R) scores to determine the ALS stage. Demographic, clinical, procedural, and follow-up data were reviewed. Results showed that the RIG tube placement had a low rate of minor adverse events (11%) and no major procedure-related adverse events. The mean ALSFRS-R score at the time of procedure in subjects who died within 90 days was lower than of those alive beyond 90 days (P = .04). This study found that RIG-tube placement is a safe and effective way to manage dysphagia in ALS patients and highlights the importance of educating members of the multidisciplinary clinic in palliative care principles to determine the appropriateness of RIG tube placement.

Therapeutics for neurodegenerative diseases by targeting the gut microbiome: from bench to bedside

The aetiologies and origins of neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS) and Huntington's disease (HD), are complex and multifaceted. A growing body of evidence suggests that the gut microbiome plays crucial roles in the development and progression of neurodegenerative diseases. Clinicians have come to realize that therapeutics targeting the gut microbiome have the potential to halt the progression of neurodegenerative diseases. This narrative review examines the alterations in the gut microbiome in AD, PD, ALS and HD, highlighting the close relationship between the gut microbiome and the brain in neurodegenerative diseases. Processes that mediate the gut microbiome-brain communication in neurodegenerative diseases, including the immunological, vagus nerve and circulatory pathways, are evaluated. Furthermore, we summarize potential therapeutics for neurodegenerative diseases that modify the gut microbiome and its metabolites, including diets, probiotics and prebiotics, microbial metabolites, antibacterials and faecal microbiome transplantation. Finally, current challenges and future directions are discussed.

Gut-Modulating Agents and Amyotrophic Lateral Sclerosis: Current Evidence and Future Perspectives

Amyotrophic Lateral Sclerosis (ALS) is a highly fatal neurodegenerative disorder characterized by the progressive wasting and paralysis of voluntary muscle. Despite extensive research, the etiology of ALS remains elusive, and effective treatment options are limited. However, recent evidence implicates gut dysbiosis and gut-brain axis (GBA) dysfunction in ALS pathogenesis. Alterations to the composition and diversity of microbial communities within the gut flora have been consistently observed in ALS patients. These changes are often correlated with disease progression and patient outcome, suggesting that GBA modulation may have therapeutic potential. Indeed, targeting the gut microbiota has been shown to be neuroprotective in several animal models, alleviating motor symptoms and mitigating disease progression. However, the translation of these findings to human patients is challenging due to the complexity of ALS pathology and the varying diversity of gut microbiota. This review comprehensively summarizes the current literature on ALS-related gut dysbiosis, focusing on the implications of GBA dysfunction. It delineates three main mechanisms by which dysbiosis contributes to ALS pathology: compromised intestinal barrier integrity, metabolic dysfunction, and immune dysregulation. It also examines preclinical evidence on the therapeutic potential of gut-microbiota-modulating agents (categorized as prebiotics, probiotics, and postbiotics) in ALS.

Gut Symptoms, Gut Dysbiosis and Gut-Derived Toxins in ALS

Many pathogenetic mechanisms have been proposed for amyotrophic lateral sclerosis (ALS). Recently, there have been emerging suggestions of a possible role for the gut microbiota. Gut microbiota have a range of functions and could influence ALS by several mechanisms. Here, we review the possible role of gut-derived neurotoxins/excitotoxins. We review the evidence of gut symptoms and gut dysbiosis in ALS. We then examine a possible role for gut-derived toxins by reviewing the evidence that these molecules are toxic to the central nervous system, evidence of their association with ALS, the existence of biochemical pathways by which these molecules could be produced by the gut microbiota and existence of mechanisms of transport from the gut to the blood and brain. We then present evidence that there are increased levels of these toxins in the blood of some ALS patients. We review the effects of therapies that attempt to alter the gut microbiota or ameliorate the biochemical effects of gut toxins. It is possible that gut dysbiosis contributes to elevated levels of toxins and that these could potentially contribute to ALS pathogenesis, but more work is required.

Autonomic dysfunction is associated with disease progression and survival in amyotrophic lateral sclerosis: a prospective longitudinal cohort study

BACKGROUND

Among non-motor symptoms, autonomic disturbances have been described in amyotrophic lateral sclerosis (ALS) and reported as mild to moderate in up to 75% of patients. However, no study has systematically investigated autonomic symptoms as prognostic factors.

OBJECTIVES

The main aim of this longitudinal study was to examine the association of autonomic dysfunction with disease progression and survival in ALS.

METHODS

We enrolled newly diagnosed ALS patients and a healthy control group (HC). Time from disease onset to disease milestone (King's stage 4) and death were calculated to assess disease progression and survival. Autonomic symptoms were assessed by a dedicated questionnaire. Longitudinal evaluation of parasympathetic cardiovascular activity was performed by the heart rate variability (HRV). Multivariable Cox proportional hazards regression models on the risk of the disease milestone and death were used. A mixed-effect linear regression model was used to compare autonomic dysfunction with a HC group as well as its impairment over time.

RESULTS

A total of 102 patients and 41 HC were studied. ALS patients, compared with HC, complained of more autonomic symptoms, especially in bulbar onset patients. Autonomic symptoms occurred in 69 (68%) patients at diagnosis and progressed over time (post-6: p = 0.015 and post-12: p < 0.001). A higher autonomic symptom burden was an independent marker of faster development of King's stage 4 (HR 1.05; 95% CI 1.00-1.11; p = 0.022); whereas, urinary complaints were independent factors of a shorter survival (HR 3.12; 95% CI 1.22-7.97; p = 0.018). Moreover, HRV in ALS patients was lower than in HC (p = 0.018) and further decreased over time (p = 0.003), implying a parasympathetic hypofunction that progressed over time.

CONCLUSION

Autonomic symptoms occur in most of the ALS patients at diagnosis and progress over time, implying that autonomic dysfunction represents an intrinsic non-motor feature of the disease. A higher autonomic burden is a poor prognostic factor, associated with a more rapid development of disease milestones and shorter survival.

Investigation of non-motor symptoms in patients with amyotrophic lateral sclerosis

[Objective] Few studies have comprehensively investigated the non-motor symptoms of amyotrophic lateral sclerosis (ALS). We aimed to investigate this aspect of ALS. [Methods] We held a nationwide webinar, titled "ALS Café," and distributed self-report questionnaires to ALS patients. In addition to the frequency of non-motor symptoms such as fatigue, pain, sleep disorders, defecation disorders, sialorrhea, and sexual problems, we evaluated the quality of life (QoL), ALS Functional Rating Scale-Revised (ALSFRS-R), and Patient Health Questionnaire-9 (PHQ-9). [Results] The average age of the 33 respondents (19 male, 14 female) was 60.8 ± 11.2; 96.7% of respondents had some non-motor symptoms. The median ALSFRS-R was 32.0, and seven (21.2%) of the respondents had a PHQ-9 score of 10 or higher. Fatigue was the most common non-motor symptom (81.8%), followed by pain (60.6%), defecation disorders (57.6%), sleep disorders (48.5%), sialorrhea (48.5%), and sexual problems (24.2%). Fatigue was more frequent in females (P = 0.03). Among the non-motor symptoms, pain was the most common factor affecting QoL, followed by fatigue. More than 90% of ALS patients answered that they had never consulted a physician/counselor about sexual problems. Patients with pain had higher PHQ-9 scores than those without (P = 0.01). There was no correlation between the ALSFRS-R score and QoL and PHQ-9. [Conclusions] Most patients with amyotrophic lateral sclerosis had non-motor symptoms, and fatigue and pain were the most common. We showed that many non-motor symptoms affected QoL without correlating with ALSFRS-R score. Attention should be paid to those even if the motor symptoms of ALS are mild.

Autonome Diagnostik bei der Amyotrophen Lateralsklerose

Bei der Amyotrophen Lateralsklerose (ALS) handelt sich um eine neurodegenerative Multisystemerkrankung. Diese äußert sich neben den motorischen Defiziten mit nicht-motorischen Symptomen. Hierzu zählen auch autonome Störungen, die von veränderter Schweißsekretion über Tachykardie bis zu gastrointestinalen Symptomen reichen. Autonome Störungen können mit verschiedenen Methoden, wie Selbsterhebungsfragebögen, Messung der Herzfrequenzvariabilität, QTc-Intervallmessung, Erhebung der sudomotorischen Funktion und Sonographie des Nervus vagus erfasst werden, die in diesem Artikel dargestellt werden. Die bislang bei der ALS eingesetzten Methoden der autonomen Diagnostik ergeben zum Teil deutlich divergierende Ergebnisse über die Aktivität des Sympathikus im Krankheitsverlauf. Relevante autonome Störungen scheinen zumeist erst im fortgeschrittenen Krankheitsstadium aufzutreten, wobei multizentrische Studien mit longitudinalem Ansatz ausstehen.

The intestinal barrier in disorders of the central nervous system

The intestinal barrier, which primarily consists of a mucus layer, an epithelial barrier, and a gut vascular barrier, has a crucial role in health and disease by facilitating nutrient absorption and preventing the entry of pathogens. The intestinal barrier is in close contact with gut microbiota on its luminal side and with enteric neurons and glial cells on its tissue side. Mounting evidence now suggests that the intestinal barrier is compromised not only in digestive disorders, but also in disorders of the central nervous system (CNS), such as Parkinson's disease, autism spectrum disorder, depression, multiple sclerosis, and Alzheimer's disease. After providing an overview of the structure and functions of the intestinal barrier, we review existing preclinical and clinical studies supporting the notion that intestinal barrier dysfunction is present in neurological, neurodevelopmental, and psychiatric disorders. On the basis of this evidence, we discuss the mechanisms that possibly link gut barrier dysfunction and CNS disorders and the potential impact that evaluating enteric barriers in brain disorders could have on clinical practice, in terms of novel diagnostic and therapeutic strategies, in the near future.