Tokyo: Like the rest of the world, Japan has seen an alarming rise in the disease chronic sinusitis (CRS) over the past decade.
A type of inflammation called RS can cause nasal congestion, discharge, difficulty breathing through the nose, facial pain, and even loss of smell. It lasts for at least 12 weeks.
Unfortunately, treatment of CRS can be challenging because of the diverse ways in which it manifests. CRS can be divided into eosinophilic (ECRS) and non-eosinophilic (non-ECRS). Eosinophils, a subset of white blood cells that release pro-inflammatory substances, are more prevalent in nasal and sinus tissue in ECRS.
The increase in the prevalence of CRS is largely driven by environmental factors, which in turn are influenced by lifestyle changes. Among various environmental factors, microorganisms present in the nasal cavities and passages are known to significantly affect our health.
However, it is unclear whether nasal microbiome Contribute to the development of ECRS.
To address this knowledge gap, a Japanese research team led by Assistant Professor Masanori Kidoguchi, School of Medical Sciences, University of Fukui, Japan, recently conducted a study of chronic sinusitis in the Japanese population, focusing on the nasal microbiota.
Their paper was also co-authored by Professor Shigeharu Fujieda from the University of Fukui and Professor Emiko Noguchi from the University of Tsukuba, and was published in the Journal of Allergy and Clinical Immunology on September 25, 2023.
“We conducted this study because the pathological functions of bacteria and their metabolites in the development of ECRS remain unknown,” said Dr. Kidoguchi.
First, the researchers collected nasal swabs from 143 subjects, 65 with ECRS, 45 with non-ECRS, and 33 healthy control subjects. They then compared the microbiome diversity between the CRS and control groups in these samples and found significant differences, suggesting that the nasal microbiome is indeed related to (or affected by) the disease.
More importantly, there were significant differences in microbiome composition between the ECRS and non-ECRS groups. Using chemical and genetic tests, the team found that ECRS patients had lower amounts of the bacterium Fusobacterium nucleatum.
Furthermore, metagenomic analysis showed that lipopolysaccharide (LPS) synthesis was higher in non-ECRS patients than in ECRS patients.
Based on these results, Dr. Kidoguchi speculated: “F nucleatum is known to cause inflammation by producing LPS. Some studies have shown that LPS has different structures and functions depending on the bacterial species. Therefore, we hypothesized that LPS derived from F nucleatum might and the pathogenesis of ECRS and non-ECRS.”
To test this hypothesis, the team investigated whether LPS isolated from F. nucleatum had an effect on the expression of specific cytokines in human bronchial epithelial cell cultures.
Their experiments showed that LPS derived specifically from F. nucleatum inhibited the expression of ALOX15, an enzyme that plays a key role in the development of nasal polyps and eosinophil-related inflammation.
Taken together, the results of this study suggest that disruption of the nasal microbiota may play a key role in ECRS. This finding could be used to develop more effective strategies to deal with this troublesome situation.
Dr. Kidoguchi commented: “The microbiome may strongly influence treatment resistance in chronic sinusitis and may also have an impact on other allergic diseases. Future research will hopefully lead to the development of probiotics and lifestyle changes to prevent refractory Chronic sinusitis.”
A type of inflammation called RS can cause nasal congestion, discharge, difficulty breathing through the nose, facial pain, and even loss of smell. It lasts for at least 12 weeks.
Unfortunately, treatment of CRS can be challenging because of the diverse ways in which it manifests. CRS can be divided into eosinophilic (ECRS) and non-eosinophilic (non-ECRS). Eosinophils, a subset of white blood cells that release pro-inflammatory substances, are more prevalent in nasal and sinus tissue in ECRS.
The increase in the prevalence of CRS is largely driven by environmental factors, which in turn are influenced by lifestyle changes. Among various environmental factors, microorganisms present in the nasal cavities and passages are known to significantly affect our health.
However, it is unclear whether nasal microbiome Contribute to the development of ECRS.
To address this knowledge gap, a Japanese research team led by Assistant Professor Masanori Kidoguchi, School of Medical Sciences, University of Fukui, Japan, recently conducted a study of chronic sinusitis in the Japanese population, focusing on the nasal microbiota.
Their paper was also co-authored by Professor Shigeharu Fujieda from the University of Fukui and Professor Emiko Noguchi from the University of Tsukuba, and was published in the Journal of Allergy and Clinical Immunology on September 25, 2023.
“We conducted this study because the pathological functions of bacteria and their metabolites in the development of ECRS remain unknown,” said Dr. Kidoguchi.
First, the researchers collected nasal swabs from 143 subjects, 65 with ECRS, 45 with non-ECRS, and 33 healthy control subjects. They then compared the microbiome diversity between the CRS and control groups in these samples and found significant differences, suggesting that the nasal microbiome is indeed related to (or affected by) the disease.
More importantly, there were significant differences in microbiome composition between the ECRS and non-ECRS groups. Using chemical and genetic tests, the team found that ECRS patients had lower amounts of the bacterium Fusobacterium nucleatum.
Furthermore, metagenomic analysis showed that lipopolysaccharide (LPS) synthesis was higher in non-ECRS patients than in ECRS patients.
Based on these results, Dr. Kidoguchi speculated: “F nucleatum is known to cause inflammation by producing LPS. Some studies have shown that LPS has different structures and functions depending on the bacterial species. Therefore, we hypothesized that LPS derived from F nucleatum might and the pathogenesis of ECRS and non-ECRS.”
To test this hypothesis, the team investigated whether LPS isolated from F. nucleatum had an effect on the expression of specific cytokines in human bronchial epithelial cell cultures.
Their experiments showed that LPS derived specifically from F. nucleatum inhibited the expression of ALOX15, an enzyme that plays a key role in the development of nasal polyps and eosinophil-related inflammation.
Taken together, the results of this study suggest that disruption of the nasal microbiota may play a key role in ECRS. This finding could be used to develop more effective strategies to deal with this troublesome situation.
Dr. Kidoguchi commented: “The microbiome may strongly influence treatment resistance in chronic sinusitis and may also have an impact on other allergic diseases. Future research will hopefully lead to the development of probiotics and lifestyle changes to prevent refractory Chronic sinusitis.”