The role of the gut microbiota in multiple sclerosis: A scientometric analysis reveals key research trends

By Tarun Sai LomteReviewed by Benedette Cuffari, M.Sc.Aug 21 2024

A recent study published in Frontiers in Immunology examines the relationship between gut microbiota (GM) and multiple sclerosis (MS).

Study: Relationship between gut microbiota and multiple sclerosis: a scientometric visual analysis from 2010 to 2023. Image Credit: Kateryna Kon / Shutterstock.com

The gut-brain-axis and MS

MS is a chronic inflammatory disease of the central nervous system (CNS) and is among the most common causes of neurologic disability in people between 18 and 40 years of age. The etiology of MS is multifactorial and heterogeneous, as it is influenced by both environmental and genetic factors.

The human GM encodes over three million genes and produces thousands of metabolites that facilitate bidirectional communication between the CNS and gastrointestinal system. Several studies have correlated GM imbalance to MS pathogenesis.

Bibliometric analyses are widely used to examine development trends, research hotspots, discipline knowledge structure, and academic influence in specific research areas using statistical and mathematic methods. Despite thousands of studies published on the relationship between GM and MS, there remains a lack of bibliometric analyses.

About the study

In the present study, researchers performed a scientometric analysis of research on the relationship between GM and MS. Relevant studies published between 2010 and 2023 were searched in the Web of Science Core Collection.

Data obtained from the search procedure were visually analyzed using multiple tools. Cooperative networks involving authors, keywords, journals, countries, and institutions were generated.

Prominent surges in publications and cited journals were identified, and trend topics were analyzed.

Study findings

Overall, 1,019 publications were identified, with a stable growth rate in the annual publication volume reported between 2010 and 2013. In 2018, a significant increase in publications was observed, with the annual volume exceeding 100 articles for the first time.

Growing interest in the relationship between GM and MS was observed as publications peaked between 2021 and 2023. The reviewed studies were conducted in 70 countries and regions, with Canada and the United States collaborating the most, followed by the U.S. and Germany.

The U.S., Italy, Germany, China, and Canada accounted for 72% of all publications. Overall, 1,581 distinct institutions contributed to these publications, with the University of California and Harvard Medical School as the top two contributing universities.

A total of 5,185 authors contributed to the reviewed publications, two of whom had the highest publications and were less collaborative with others. The author with the most publications also had the highest number of citations.

The reviewed articles were published in a total of 359 journals. The top five journals included Multiple Sclerosis Journal, Frontiers in Immunology, International Journal of Molecular Sciences, Nutrients, and Multiple Sclerosis and Related Disorders. The top three publications were cited over 500 times, with 796 citations identified for a single article.

Keyword co-occurrence networks were created, and each keyword had a minimum frequency of five. The keyword network was stratified into five clusters comprising 52, 30, 30, 24, and 30 keywords, respectively.

The first cluster involved keywords related to the role of diet in autoimmune diseases and the impact of probiotics and microbiome on autoimmunity. The second cluster centered on the relationship between GM and systemic immune-mediated diseases.

The third cluster included keywords on the associations and mechanisms between GM and neurologic diseases. The fourth cluster included microglia, ketogenic diet, neurodegeneration, dysbiosis, neuroinflammation, and immunity. The final cluster involved keywords on mental health, especially depression.

Experimental autoimmune encephalomyelitis (EAE) was the most frequently used mouse model for MS. GM was also associated with neurodegenerative diseases, such as Alzheimer’s disease and Parkinson’s disease.

The most prominent keywords before 2018 were autoimmune disease, immunity, estrogen, inflammatory bowel disease, and T helper 17 (Th17) cells, which reflects that research was focused on the role of GM in the immune mechanisms of MS. Between 2019 and 2020, the most common keywords were EAE, MS, microbiome, and inflammation, thus suggesting research focus on the role of GM in clinical studies and animal models.

After 2021, high-frequency keywords included the gut-brain axis, probiotics, dysbiosis, aging, and neurodegenerative disease. This observation indicates a research transition, with an emphasis on understanding the impact of GM in aging and neurodegenerative diseases.

Conclusions

The emergence of tools such as metagenomic shotgun sequencing and 16s ribosomal ribonucleic acid (rRNA) gene pyrosequencing has significantly contributed to the growing number of research studies investigating the relationship between GM and MS. Future studies are needed to examine the role of gut dysbiosis in MS pathogenesis and investigate the underlying interaction mechanisms between GM and MS.