A preliminary therapeutic study of the effects of molecular hydrogen on intestinal dysbiosis and small intestinal injury in high-fat diet-loaded senescence-accelerated mice

OBJECTIVES

Aging and excessive fat intake may additively induce dysbiosis of the gut microbiota and intestinal inflammatory damage. Here, we analyzed microbiota dysbiosis and intestinal injury in high-fat diet-loaded senescence-accelerated mice (SAMP8). Additionally, we examined whether treatment with molecular hydrogen could improve the intestinal environment.

METHODS

SAMP8 and SAMR1 (control) mice were first fed a normal diet (ND) or high-fat diet (HFD) for 10 wk (n = 10 each group). Subsequently, HFD was supplemented with a placebo jelly or hydrogen-rich jelly (HRJ) for 4 wk. After treatment, isolated small intestinal tissues were used for hematoxylin and eosin staining, immunofluorescence staining, and thiobarbituric acid reactive substances (TBARS) assay. Furthermore, we analyzed alterations in the microbiota composition in cecal feces using 16S rRNA gene analysis for microbiota profiling. Statistical analyses were performed using unpaired Student's t tests or one-way analysis of variance and Tukey's post hoc test for multiple comparisons.

RESULT

HFD feeding reduced the expression of caudal-related homeobox transcription factor 2 (CDX2) and 5-bromo-2'-deoxyuridine (BrdU) and enhanced malondialdehyde (MDA) levels in the small intestine of SAMP8. HRJ treatment improved the reduction in CDX2 and BrdU and enhanced MDA levels. We performed a sequence analysis of the gut microbiota at the genus level and identified 283 different bacterial genera from the 30 samples analyzed in the study. Among them, Parvibacter positively correlated with both HFD intake and aging, whereas 10 bacteria, including Anaerofustis, Anaerosporobacter, Butyricicoccus, and Ruminococcus were negatively correlated with both HFD and aging. HRJ treatment increased Lactinobactor and decreased Akkermansia, Gracilibacter, and Marvinbryantia abundance.

CONCLUSION

Our findings suggest that treatment with molecular hydrogen may affect microbiota profiling and suppress intestinal injury in HFD-loaded SAMP8.

Microbial analysis reveals the potential colonization of pathogens in the intestine of crayfish (Procambarus clarkii) in traditional aquaculture environments

The microbiota of the intestine produces a wide array of biologically active molecules and together act as a composite endocrine organ. Due to our limited understanding of bacterial communities in aquaculture ecosystems, it is necessary to evaluate the interactions between environmental and intestinal microbiota and the potential consequences of disease. This study taken the traditional P. clarkii culture in the Sichuan Basin as an example, and analyzed the relationships between the microbiota of the environment and host through microbial analysis and microbiological diagnosis. Our results showed that the bacterial abundance in sediment was greater than in water, followed by the intestine, and some of bacteria from the environment successfully selected to colonize the intestine. The bacterial composition in the intestines of diseased and healthy crayfish was significantly different. The bacteria that colonized and proliferated in the intestine had very low abundances in sediment and water. Two potential pathogens, Aeromonas veronii, and Citrobacter freundii, and two potential probiotics, Lactococcus garvieae and Exiguobacterium undae, were identified. Using multiple, real, and traditional P. clarkii aquaculture sites in the Sichuan Basin, this study revealed that the microbial communities of the environment and animal host did indeed interact. Furthermore, these results indicated that P. clarkii in a healthy status are capable of regulating which bacteria colonize their intestines.

Implementation of microbiota analysis in clinical trials for cystic fibrosis lung infection: Experience from the OligoG phase 2b clinical trials

Culture-independent microbiota analysis is widely used in research and being increasingly used in translational studies. However, methods for standardisation and application of these analyses in clinical trials are limited. Here we report the microbiota analysis that accompanied two phase 2b clinical trials of the novel, non-antibiotic therapy OligoG CF-5/20 for cystic fibrosis (CF) lung infection. Standardised protocols (DNA extraction, PCR, qPCR and 16S rRNA gene sequencing analysis) were developed for application to the Pseudomonas aeruginosa (NCT02157922) and Burkholderia cepacia complex (NCT02453789) clinical trials involving 45 and 13 adult trial participants, respectively. Microbiota analysis identified that paired sputum samples from an individual participant, taken within 2 h of each other, had reproducible bacterial diversity profiles. Although culture microbiology had identified patients as either colonised by P. aeruginosa or B. cepacia complex species at recruitment, microbiota analysis revealed patient lung infection communities were not always dominated by these key CF pathogens. Microbiota profiles were patient-specific and remained stable over the course of both clinical trials (6 sampling points over the course of 140 days). Within the Burkholderia trial, participants were infected with B. cenocepacia (n = 4), B. multivorans (n = 6), or an undetermined species (n = 3). Colonisation with either B. cenocepacia or B. multivorans influenced the overall bacterial community structure in sputum. Overall, we have shown that sputum microbiota in adults with CF is stable over a 2 h time-frame, suggesting collection of a single sample on a collection day is sufficient to capture the microbiota diversity. Despite the uniform pathogen culture-positivity status at recruitment, trial participants were highly heterogeneous in their lung microbiota. Understanding the microbiota profiles of individuals with CF ahead of future clinical trials would be beneficial in the context of patient stratification and trial design.

Effects of imidacloprid on the oxidative stress, detoxification and gut microbiota of Chinese mitten crab, Eriocheir sinensis

Imidacloprid (IMI) is used in integrated aquaculture systems for pest control and the toxicity of IMI to non-target aquatic animals such as fish and microcrustaceans has been recognised. However, knowledge about the toxic effect of IMI on commercial crabs is still scarce. In the present study, effects of IMI on the acute toxicity, antioxidative status, detoxification systems and gut microbiota in Chinese mitten crab, Erocheir sinensis were investigated. In the present study, the 96-h LC₅₀ of IMI for E. sinensis was 24.97 mg/L. Under sublethal exposure, superoxide dismutase (SOD) activities increased under low concentration (LC, 5 μg/L) and median concentration (MC, 50 μg/L) exposure, but decreased in high concentration group (HC, 500 μg/L). Activities of catalyse (CAT) decreased in a dose-dependent manner. Detoxification-related enzymes aminopyrine N-demethylase (APND) and erythromycin N-demethylase (ERND) increased in all treatments whereas glutathione-S-transferase (GST) decreased dose-dependently. The relative mRNA expression of the cytochrome P4502 (cyp2) gene was induced significantly in LC and HC groups while no significant change was observed in cytochrome P4503 (cyp3) gene. The expression of gst was also significantly decreased in HC group. Up-regulation of heat shock protein hsp70 and 90 was observed in MC and HC groups whereas hsp60 up-regulated only in LC group. In addition, significant changes of composition of microbial communities at both phylum and genus levels were found in this test. In particular, beneficial bacteria were found to decrease and pathogens increased after exposure to IMI. These results indicate that high concentration of IMI could induce oxidative stress and suppress the detoxification system mainly by down-regulation of gst mRNA expression, inhibition of enzyme activities and dysbiosis of gut microbiota.

Comparison of Amsel criteria, Nugent score, culture and two CE-IVD marked quantitative real-time PCRs with microbiota analysis for the diagnosis of bacterial vaginosis

Bacterial vaginosis (BV) is a common gynaecological condition. Diagnosis of BV is typically based on Amsel criteria, Nugent score and/or bacterial culture. In this study, these conventional methods and two CE-IVD marked quantitative real-time (q)PCR assays were compared with microbiota analysis for the diagnosis of BV. Eighty women were evaluated for BV during two sequential hospital visits by Amsel criteria, Nugent score, culture, the AmpliSens® Florocenosis/Bacterial vaginosis-FRT PCR kit (InterLabService, Moscow, Russia), and the BD MAX™ Vaginal Panel (BD Diagnostics, MD, USA). Microbiota analysis based on amplicon sequencing of the 16S ribosomal RNA gene was used as reference test. The microbiota profile of 36/115 (31%) included cases was associated with BV. Based on microbiota analysis, the sensitivity of detecting BV was 38.9% for culture, 61.15% for Amsel criteria, 63.9% for Nugent score and the BD MAX assay, and 80.6% for the AmpliSens assay, while the specificity of all methods was ≥ 92.4%. Microbiota profiles of the cases with discrepant results between microbiota analysis and the diagnostic methods were variable. All five diagnostic methods missed BV positive cases with a relatively high abundance of the genus Alloscardovia, Bifidobacterium, or Dialister, which were categorised as unspecified dysbiosis by the AmpliSens assay. Compared to Amsel criteria, Nugent score, culture, and the BD MAX assay, the AmpliSens assay was most in agreement with microbiota analysis, indicating that currently, the AmpliSens assay may be the best diagnostic method available to diagnose BV in a routine clinical setting.

Understanding and overcoming the pitfalls and biases of next-generation sequencing (NGS) methods for use in the routine clinical microbiological diagnostic laboratory

Recent advancements in next-generation sequencing (NGS) have provided the foundation for modern studies into the composition of microbial communities. The use of these NGS methods allows for the detection and identification of (‘difficult-to-culture’) microorganisms using a culture-independent strategy. In the field of routine clinical diagnostics however, the application of NGS is currently limited to microbial strain typing for epidemiological purposes only, even though the implementation of NGS for microbial community analysis may yield clinically important information. This lack of NGS implementation is due to many different factors, including issues relating to NGS method standardization and result reproducibility. In this review article, the authors provide a general introduction to the most widely used NGS methods currently available (i.e., targeted amplicon sequencing and shotgun metagenomics) and the strengths and weaknesses of each method is discussed. The focus of the publication then shifts toward 16S rRNA gene NGS methods, which are currently the most cost-effective and widely used NGS methods for research purposes, and are therefore more likely to be successfully implemented into routine clinical diagnostics in the short term. In this respect, the experimental pitfalls and biases created at each step of the 16S rRNA gene NGS workflow are explained, as well as their potential solutions. Finally, a novel diagnostic microbiota profiling platform (‘MYcrobiota’) is introduced, which was developed by the authors by taking into consideration the pitfalls, biases, and solutions explained in this article. The development of the MYcrobiota, and future NGS methodologies, will help pave the way toward the successful implementation of NGS methodologies into routine clinical diagnostics.