Association between increased and decreased gut microbiota abundance and Parkinson's disease: A systematic review and subgroup meta-analysis

OBJECTIVE

The objective of the study was to systematically investigate the association between gut microbiota (GM) abundance and Parkinson's disease (PD).

METHODS

PubMed, Medline, Cochrane Library and other literature datebase platforms were searched for eligible studies in the English-language from conception to March 1, 2024. Studies evaluating the association between GM and PD were included. The results of the included studies were analyzed using a random effects model with calculation of the mean difference (MD) with the 95 % confidence interval to quantify the incidence of differences in abundance of various bacterial families in PD patients. Continuous models were used to analyze the extracted data.

RESULTS

A total of 14 studies with 1045 PD cases and 821 healthy controls were included for data extraction and meta-analysis. All the included studies exhibited reasonable quality. The included studies reported the data on the ratios of 10 families of GM. Of these 10 microbiota families, Bifidobacteriaceae, Ruminococcaceae, Rikenellaceae, Lactobacillaceae, Verrucomicrobiaceae and Christensenellaceae were found to have increased ratios according to the pooled ratios, while Prevotellaceae, Lachnospiraceae, Erysipelotrichaceae and Faecalibacterium were decreased in PD cases.

CONCLUSION

Patients in the PD cohort exhibited distinctive microbiota compositions compared to healthy individuals, with unique differential patterns in gut microbiome abundance at the phylum, family, and genus levels that may be associated wtih PD pathogenesis.

Domestic hot-water boilers harbour active thermophilic bacterial communities distinctly different from those in the cold-water supply

Running cold and hot water in buildings is a widely established commodity. However, interests regarding hygiene and microbiological aspects had so far been focussed on cold water. Little attention has been given to the microbiology of domestic hot-water installations (DHWIs), except for aspects of pathogenic Legionella. World-wide, regulations consider hot (or warm) water as 'heated drinking water' that must comply (cold) drinking water (DW) standards. However, the few reports that exist indicate presence and growth of microbial flora in DHWIs, even when supplied with water with disinfectant residual. Using flow cytometric (FCM) total cell counting (TCC), FCM-fingerprinting, and 16S rRNA-gene-based metagenomic analysis, the characteristics and composition of bacterial communities in cold drinking water (DW) and hot water from associated boilers (operating at 50 - 60 °C) was studied in 14 selected inhouse DW installations located in Switzerland and Austria. A sampling strategy was applied that ensured access to the bulk water phase of both, supplied cold DW and produced hot boiler water. Generally, 1.3- to 8-fold enhanced TCCs were recorded in hot water compared to those in the supplied cold DW. FCM-fingerprints of cold and corresponding hot water from individual buildings indicated different composition of cold- and hot-water microbial floras. Also, hot waters from each of the boilers sampled had its own individual FCM-fingerprint. 16S rRNA-gene-based metagenomic analysis confirmed the marked differences in composition of microbiomes. E.g., in three neighbouring houses supplied from the same public network pipe each hot-water boiler contained its own thermophilic bacterial flora. Generally, bacterial diversity in cold DW was broad, that in hot water was restricted, with mostly thermophilic strains from the families Hydrogenophilaceae, Nitrosomonadaceae and Thermaceae dominating. Batch growth assays, consisting of cold DW heated up to 50 - 60 °C and inoculated with hot water, resulted in immediate cell growth with doubling times between 5 and 10 h. When cold DW was used as an inoculum no significant growth was observed. Even boilers supplied with UVC-treated cold DW contained an actively growing microbial flora, suggesting such hot-water systems as autonomously operating, thermophilic bioreactors. The generation of assimilable organic carbon from dissolved organic carbon due to heating appears to be the driver for growth of thermophilic microbial communities. Our report suggests that a man-made microbial ecosystem, very close to us all and of potential hygienic importance, may have been overlooked so far. Despite consumers having been exposed to microbial hot-water flora for a long time, with no major pathogens so far been associated specifically with hot-water usage (except for Legionella), the role of harmless thermophiles and their interaction with potential human pathogens able to grow at elevated temperatures in DHWIs remains to be investigated.

Bacterial communities along parrot digestive and respiratory tracts: the effects of sample type, species and time

Digestive and respiratory tracts are inhabited by rich bacterial communities that can vary between their different segments. In comparison with other bird taxa with developed caeca, parrots that lack caeca have relatively lower variability in intestinal morphology. Here, based on 16S rRNA metabarcoding, we describe variation in microbiota across different parts of parrot digestive and respiratory tracts both at interspecies and intraspecies levels. In domesticated budgerigar (Melopsittacus undulatus), we describe the bacterial variation across eight selected sections of respiratory and digestive tracts, and three non-destructively collected sample types (faeces, and cloacal and oral swabs). Our results show important microbiota divergence between the upper and lower digestive tract, but similarities between respiratory tract and crop, and also between different intestinal segments. Faecal samples appear to provide a better proxy for intestinal microbiota composition than the cloacal swabs. Oral swabs had a similar bacterial composition as the crop and trachea. For a subset of tissues, we confirmed the same pattern also in six different parrot species. Finally, using the faeces and oral swabs in budgerigars, we revealed high oral, but low faecal microbiota stability during a 3-week period mimicking pre-experiment acclimation. Our findings provide a basis essential for microbiota-related experimental planning and result generalisation in non-poultry birds.

Sediment microbial community characteristics in sea cucumber restocking area

Variations of microbial species and functional composition in coastal sediment are usually taken as the results of the provision of supplementary nutrients affected by human activities. However, responses of microbiome stability to restocking biological resources remain less understood in coastal benthic systems without nutrient supplements. Here, combined with metagenomics and microbiome co-occurrence networks, the composition, function, and community stability of microbes were evaluated in a coastal area where sea cucumbers (Apostichopus japonicus) restocked after six months. Also, the physicochemical characteristics of sediments and bottom water were analyzed. We found the total organic carbon, total nitrogen, and total phosphorus of sediment did not change significantly in the restocking area after six months, whereas the concentration of dissolved inorganic nitrogen in bottom water increased significantly. Moreover, the relative abundance of Nitrospina at the class level was increased significantly in the restocking area. Also, enzymes related to nitrate reduction and nitrous oxide reductase were increased in the restocking area. Of note, stock enhancement of sea cucumbers altered associations between bacteria rather than their composition. The elimination of negative associations and reduction of the potential keystone taxa in the restocking area indicated destabilized bacterial communities. Our work may contribute to elucidating the response of microbial stability to stock enhancement. This finding also suggests that microbial community stability can be considered as an indicator of ecological risk under the influence of stock enhancement.

Difference in microbiome compositions of healthy peri-implant sulcus and peri-implantitis sulcus from the same patient

Objective

The objective of this study is to compare the microbiome of healthy peri-implant sulcus (C) and peri-implantitis sulcus (U) from the same patient and analyze the difference in the microbiome composition.

Materials and methods

DNA samples of subgingival biofilms from 10 C (control group) and 10 U (uncontrolled group) sites were sent to Microbiome Center in Korea Research Institute of Biomedical Science and analyzed using 16s rRNA gene amplification and sequencing (MiSeq, Illumina) and human oral microbiome database (HOMD).

Results

At the phylum level, Firmicutes and Proteobacteria were more abundant in group C, while Firmicutes and Bacteroidetes were dominant in group U. At the genus level, the core peri-implant microbiome was Streptococcus in group C. On the other hand, the core peri-implant microbiome was Porphyromonas, especially P. gingivalis in group U.

Conclusion

In this study, the microbiome composition of peri-implantitis sulcus was different from that of healthy peri-implant sulcus from the same patient. The peri-implantitis microbiome was pathogen-enriched and was similar to the microbiome associated with periodontitis.

Microbiome composition indicate dysbiosis and lower richness in tumor breast tissues compared to healthy adjacent paired tissue, within the same women

Background

Breast cancer (BC) is the most common malignancy in women, in whom it reaches 20% of the total neoplasia incidence. Most BCs are considered sporadic and a number of factors, including familiarity, age, hormonal cycles and diet, have been reported to be BC risk factors. Also the gut microbiota plays a role in breast cancer development. In fact, its imbalance has been associated to various human diseases including cancer although a consequential cause-effect phenomenon has never been proven.

Methods

The aim of this work was to characterize the breast tissue microbiome in 34 women affected by BC using an NGS-based method, and analyzing the tumoral and the adjacent non-tumoral tissue of each patient.

Results

The healthy and tumor tissues differed in bacterial composition and richness: the number of Amplicon Sequence Variants (ASVs) was higher in healthy tissues than in tumor tissues (p = 0.001). Moreover, our analyses, able to investigate from phylum down to species taxa for each sample, revealed major differences in the two richest phyla, namely, Proteobacteria and Actinobacteria. Notably, the levels of Actinobacteria and Proteobacteria were, respectively, higher and lower in healthy with respect to tumor tissues.

Conclusions

Our study provides information about the breast tissue microbial composition, as compared with very closely adjacent healthy tissue (paired samples within the same woman); the differences found are such to have possible diagnostic and therapeutic implications; further studies are necessary to clarify if the differences found in the breast tissue microbiome are simply an association or a concausative pathogenetic effect in BC. A comparison of different results on similar studies seems not to assess a universal microbiome signature, but single ones depending on the environmental cohorts’ locations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-09074-y.

Clinical observation and preliminary study of mechanism of daphnetin in improving therapeutic effects for colitis

BACKGROUND

Daphnein is the first new drug in China. In addition to the treatment of cardiovascular diseases and coronary heart disease, daphnein also has anti-inflammatory, anti-apoptosis, analgesia, and immunity-enhancing activities. Some studies have reported that daphnetin may inhibit the activities of cyclooxygenase and 5-ester oxidase and produce anti-inflammatory and anti-allergic reactions by inhibiting the synthesis of prostaglandin and leukotriene.

AIM

To explore the efficacy of daphnetin in the treatment of colitis, and observe its effect on the composition of microbiota and the balance of regulatory T cells (Treg)/helper Th17 cells (Th17).

METHODS

One hundred and eight patients with ulcerative colitis (UC) admitted to our hospital from June 2017 to November 2019 were selected and randomly divided into either a control group or an observation group, with 54 cases in each group. Both groups were given conventional Western medicine treatment, and the observation group was additionally given daphnetin. The total effective rate, Baron endoscopic score, Geboes mucosal histology score, modified Mayo activity index, intestinal flora distribution, Treg/Th17 balance changes [CD4⁺CD25⁺Foxp3⁺ Treg, interleukin-10 (IL-10), transforming growth factor β (TGF-β), CD3⁺CD4⁺IL-17A⁺ Th17, interleukin-17 (IL-17), and interleukin-21 (IL-21)], the simplified Chinese version of the Inflammatory Bowel Disease Quality of Life Scale (IBDQ) score, and adverse reactions of the two groups were compared.

RESULTS

The total effective rate of the observation group was 90.74%, which was higher than that of the control group (70.37%; P < 0.05). Baron endoscopy score, Geboes mucosal histology score, and modified Mayo activity index of the observation group after treatment were significantly lower than those of the control group (P < 0.05). The numbers of E. coli, Bacteroides, and Enterococcus in the observation group were significantly lower and those of Lactobacillus and Bifidobacterium were significantly higher in the observation group than in the control group (P < 0.05). CD4⁺CD25⁺Foxp3⁺ Treg, IL-10, and TGF-β were significantly higher and CD3⁺CD4⁺IL-17A⁺ Th17, IL-17, and IL-21 were significantly lower in the observation group than in the control group (P < 0.05). The scores of emotional ability, intestinal symptoms, social ability, and systemic symptoms on the IBDQ scale were significantly higher in the observation group than in the control group (P < 0.05).

CONCLUSION

Daphnetin can promote the healing of the intestinal mucosa of UC patients by modulating the microbiome composition and Treg/Th17 balance and effectively improve the patient's condition and quality of life, which is safe and reliable.

Early-life intestinal microbiome in Trachemys scripta elegans analyzed using 16S rRNA sequencing

During the early-life period, the hatchlings of red-eared slider turtles (Trachemys scripta elegans) rely on their own post-hatching internal yolk for several days before beginning to feed. The gut microbiome is critical for the adaptation of organisms to new environments, but, to date, how the microbiome taxa are assembled during early life of the turtle is unknown. In this study, the intestinal microbiome of red-eared slider hatchlings (fed on commercial particle food) was systematically analyzed at four different growth stages (0 d, 10 d, 20 d, 30 d) by a high-throughput sequencing approach. Results showed that the dominant phyla were Firmicutes (58.23%) and Proteobacteria (41.42%) at 0-day, Firmicutes (92.94%) at 10-day, Firmicutes (67.08%) and Bacteroidetes (27.17%) at 20-day, and Firmicutes (56.46%), Bacteroidetes (22.55%) and Proteobacteria (20.66%) at 30-day post-hatching. Members of the Bacteroidaceae family were absent in 0-day and 10-day turtles, but dominated in 20-day and 30-day turtles. The abundance of Clostridium also showed the highest value in 10-day turtles. The richness of the intestinal microbiomes was lower at 0-day and 30-day than that at 10-day and 20-day, while the diversity was higher at 10-day and 30-day than that at 0-day and 20-day. The results endowed the turtles with an ability to enhance their tolerance to the environment.

Processing and Analyzing Human Microbiome Data

The human microbiome is associated with complex disorders such as diabetes, cancer, obesity and cardiovascular disorders. Recent technological developments have allowed researchers to fully quantify the composition of the microbiome using culture-independent approaches, resulting in a large amount of microbiome data, which provide invaluable opportunities to assess the important contributions of the microbiome to human health and disease. In this chapter, we discuss and evaluate multiple statistical approaches for processing, summarizing, and analyzing microbiome data. Specifically, we provide programming scripts for processing microbiome data using QIIME and calculating alpha and beta diversities, assessing the association between diversities and outcomes of interest using R programs, as well as interpretation of results. We illustrate the methods in the context of analyzing the foregut microbiome in esophageal adenocarcinoma.

A fast small-sample kernel independence test for microbiome community-level association analysis

To fully understand the role of microbiome in human health and diseases, researchers are increasingly interested in assessing the relationship between microbiome composition and host genomic data. The dimensionality of the data as well as complex relationships between microbiota and host genomics pose considerable challenges for analysis. In this article, we apply a kernel RV coefficient (KRV) test to evaluate the overall association between host gene expression and microbiome composition. The KRV statistic can capture nonlinear correlations and complex relationships among the individual data types and between gene expression and microbiome composition through measuring general dependency. Testing proceeds via a similar route as existing tests of the generalized RV coefficients and allows for rapid p-value calculation. Strategies to allow adjustment for confounding effects, which is crucial for avoiding misleading results, and to alleviate the problem of selecting the most favorable kernel are considered. Simulation studies show that KRV is useful in testing statistical independence with finite samples given the kernels are appropriately chosen, and can powerfully identify existing associations between microbiome composition and host genomic data while protecting type I error. We apply the KRV to a microbiome study examining the relationship between host transcriptome and microbiome composition within the context of inflammatory bowel disease and are able to derive new biological insights and provide formal inference on prior qualitative observations.