Similar fungal gut microbiota found in MG patients, healthy adults: Study

MYBIOM analysis reveals no prominent imbalances in fungal species in the gut

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by Andrea Lobo |

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An illustration of the digestive system.

Composition of the fungal species present in the gut — known as the fungal gut microbiota — does not differ significantly between people with myasthenia gravis (MG) and those with other neurological disorders or healthy people.

That’s according to an analysis of the fungal gut microbiota of participants in the MYBIOM study in Germany, which aimed to determine whether the gut microbiome — the group of microbes living in the gut — is altered in MG patients compared with those with non-inflammatory or inflammatory neurological disorders.

Researchers noted that additional studies are needed to further explore the relationship between the gut microbiome and MG, as well as between fungi and autoimmunity.

The study, “Fungal Gut Microbiome in Myasthenia Gravis: A Sub-Analysis of the MYBIOM Study,” was published in the Journal of Fungi.

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Past research implicates bacterial gut microbiota as predisposing factor for MG

MG is an autoimmune-mediated disorder caused by the production of self-reactive antibodies that target different proteins involved in nerve-muscle communication, ultimately leading to muscle weakness and fatigue.

The gut microbiome comprises the vast community of bacteria, fungi, and viruses that colonize the gastrointestinal tract. These microorganisms are known to play a key role in maintaining a balanced gut function, protecting against disease-causing organisms, and influencing the body’s immune system.

Past research, including previous data from the MYBIOM study, implicated bacterial gut microbiota as a predisposing factor for MG and as a contributor to disease severity. However, data on fungal gut microbiota profiles of MG patients, and whether it differs from that of people with other neurological disorders or healthy individuals, is still lacking.

Therefore, researchers conducted a sub-analysis of the MYBIOM study to determine whether the fungal gut microbiota profile is different in MG patients compared with people with non-inflammatory neurological disorders (NINDs) or chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), an inflammatory neurological disorder. For comparison, the researchers also assessed fungal gut microbiota composition in healthy volunteers with no neurological disorders.

The study was conducted at the University Hospital of Essen in Germany from July 2017 to March 2018. Over that period of time, 77 stool samples were collected and analyzed.

After excluding the samples in which fungi were not detected, the researchers selected 51 for further analysis, including 27 from people with MG, four from patients with CIDP, 11 from those with NINDs, and nine from healthy volunteers.

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Analysis finds 4 mold species, 5 yeast species in gut microbiota of 51 people

Stool sample analyses revealed fungal gut microbiota composition comprised several species of yeasts and molds. Overall, four mold species (Penicillium aurantiogriseum, Mycosphaerella tassiana, Cladosporium ramonetellum, and Alternaria betae-kenyensi) and five yeast species (C. albicans, C. sake, C. dubliniensis, Pichia deserticola, and Kregervanrija delftensis) were identified.

While mold is a type of fungus that grows in filaments made up of several cells that form a single organism, yeast is a type of fungus that grows as a single cell.

Although one of the MG patients had an abnormal abundance of C. albicans, no other prominent imbalances in the fungal gut microbiome of MG patients were found.

Moreover, there were no significant differences between MG patients and those with other diseases or healthy volunteers.

“However, due to the small groups, further investigations are required to assess associations of the [fungal microbiome] with MG and interactions between fungi and autoimmunity, including analysis of fungal functional profiles and immune responses,” the researchers wrote.