Experimental colonization with Blastocystis ST4 is associated with protective immune responses and modulation of gut microbiome in a DSS-induced colitis mouse model.

BACKGROUND: Blastocystis is a common gut protistan parasite in humans and animals worldwide, but its interrelationship with the host gut microbiota and mucosal immune responses remains poorly understood. Different murine models of Blastocystis colonization were used to examine the effect of a common Blastocystis subtype (ST4) on host gut microbial community and adaptive immune system. RESULTS: Blastocystis ST4-colonized normal healthy mice and Rag1-/- mice asymptomatically and was able to alter the microbial community composition, mainly leading to increases in the proportion of Clostridia vadinBB60 group and Lachnospiraceae NK4A136 group, respectively. Blastocystis ST4 colonization promoted T helper 2 (Th2) response defined by interleukin (IL)-5 and IL-13 cytokine production, and T regulatory (Treg) induction from colonic lamina propria in normal healthy mice. Additionally, we observed that Blastocystis ST4 colonization can maintain the stability of bacterial community composition and induce Th2 and Treg immune responses to promote faster recovery from experimentally induced colitis. Furthermore, fecal microbiota transplantation of Blastocystis ST4-altered gut microbiome to colitis mice reduced the severity of colitis, which was associated with increased production of short-chain fat acids (SCFAs) and anti-inflammatory cytokine IL-10. CONCLUSIONS: The data confirm our hypothesis that Blastocystis ST4 is a beneficial commensal, and the beneficial effects of Blastocystis ST4 colonization is mediated through modulating of the host gut bacterial composition, SCFAs production, and Th2 and Treg responses in different murine colonization models.

Health literacy and self-care among patients with chronic kidney disease in a primary care setting.

INTRODUCTION: The study objective was to determine the levels of self-care and health literacy (HL) and their associations among patients with chronic kidney disease (CKD). METHODS: This was a cross-sectional, questionnaire-based study conducted in a public primary care setting in Singapore. A total of 289 participants aged 21-80 years with hypertension were recruited. Self-care profiles were measured using the Hypertension Self-Care Profile (HTN-SCP; range 0-240, domain range 0-80). Health literacy was measured using the Short-Form Health Literacy Scale (HLS-SF12; range 0-50, limited literacy ≤33). RESULTS: The mean self-care score was 182.7 (standard deviation [SD] 23.2). The median HL score was 34.7 (interquartile range [IQR] 31.9-40.3), and 31.1% of participants had limited HL. Self-care was not associated with age, CKD status, household income and education, but was associated with gender and HL score. In the final regression model, lower HL scores (adjusted ß = 1.03, 95% confidence interval [CI] 0.7 to 1.36, P < 0.001) and male gender (adjusted ß = -5.29, 95% CI -10.56 to -0.03, P = 0.049) were associated with lower self-care scores. The HL scores were associated with self-care domains of self-efficacy (HL: ß = 0.30, 95% CI 0.17 to 0.42, P < 0.001), motivation (HL: ß = 0.40, 95% CI 0.26 to 0.53, P < 0.001) and behaviour (HL: ß = 0.38, 95% CI 0.26 to 0.50, P < 0.001). CONCLUSION: Thirty-one percent of the participants had limited HL. Self-care was not associated with age, race, CKD status, household income or education. Male gender and limited HL were associated with lower self-care. Self-care was associated with self-efficacy, motivation and behaviour. Future research could focus on more targeted approaches to improve self-care and HL among patients with CKD.

The synthesis of extracellular vesicles by the protistan parasite Blastocystis.

Blastocystis is a genus of single-celled protist belonging to the stramenopile group. Prior studies have shown that isolates of Blastocystis subtype 7 (ST7) induced higher levels of intestinal epithelial cell damage and gut microbiota dysbiosis in comparison to other subtypes in in vivo and in vitro settings. Prior research has shown a link between gut dysbiosis and exposure to extracellular vesicles (EVs) produced by pathogenic microorganisms. This study demonstrates a protocol for the isolation of EVs from Blastocystis ST7 via ultracentrifugation. Nanoparticle tracking analysis and transmission electron microscopy were used to assess EV size and morphology. The protein content of isolated EVs was assessed by mass spectrophotometry and the presence of EV markers were evaluated by Western blotting. Finally, the EVs were cocultured with prominent human gut microbiome species to observe their effect on prokaryote growth. Our data shows that Blastocystis ST7 secretes EVs that are similar in morphology to previously characterized EVs from other organisms and that these EVs contain a limited yet unique protein cargo with functions in host-parasite intercellular communication and cell viability. This cargo may be involved in mediating the effects of Blastocystis on its surrounding environment.

Characterisation of novel functionality within the Blastocystis tryptophanase gene.

In recent years, the human gut microbiome has been recognised to play a pivotal role in the health of the host. Intestinal homeostasis relies on this intricate and complex relationship between the gut microbiota and the human host. While much effort and attention has been placed on the characterization of the organisms that inhabit the gut microbiome, the complex molecular cross-talk between the microbiota could also exert an effect on gastrointestinal conditions. Blastocystis is a single-cell eukaryotic parasite of emerging interest, as its beneficial or pathogenic role in the microbiota has been a subject of contention even to-date. In this study, we assessed the function of the Blastocystis tryptophanase gene (BhTnaA), which was acquired by horizontal gene transfer and likely to be of bacterial origin within Blastocystis. Bioinformatic analysis and phylogenetic reconstruction revealed distinct divergence of BhTnaA versus known bacterial homologs. Despite sharing high homology with the E. coli tryptophanase gene, we show that Blastocystis does not readily convert tryptophan into indole. Instead, BhTnaA preferentially catalyzes the conversion of indole to tryptophan. We also show a direct link between E. coli and Blastocystis tryptophan metabolism: In the presence of E. coli, Blastocystis ST7 is less able to metabolise indole to tryptophan. This study examines the potential for functional variation in horizontally-acquired genes relative to their canonical counterparts, and identifies Blastocystis as a possible producer of tryptophan within the gut.