A Universal Strategy to Promote Secretion of G+/G- Bacterial Extracellular Vesicles and Its Application in Host Innate Immune Responses.

Both Gram-positive and Gram-negative bacteria release nanosized extracellular vesicles called membrane vesicles (MVs, 20-400 nm), which have great potential in various biomedical applications due to their abilities to deliver effector molecules and induce therapeutic responses. To fully utilize bacterial MVs for therapeutic purposes, regulated and enhanced production of MVs would be highly advantageous. In this study, we developed a universal method to enhance MV yields in both G+/G- bacteria through an autonomous controlled peptidoglycan hydrolase (PGase) expression system. A significant increase (9.37-fold) of MV concentration was observed in engineered E. coli Nissle 1917 compared to the wild-type. With the help of this autonomous system, for the first time we experimentally confirmed horizontal gene transfer and nutrient acquisition in a cocultured bacterial consortium. Furthermore, the engineered probiotic E. coli strains with high yield of MVs showed higher activation of the innate immune responses in human embryonic kidney 293T (HEK293T) and human colorectal carcinoma cells (HCT116), thereby demonstrating the great potential of engineering probiotics in immunology and further living therapeutics in humans.

Histamine production by the gut microbiota induces visceral hyperalgesia through histamine 4 receptor signaling in mice.

The gut microbiota has been implicated in chronic pain disorders, including irritable bowel syndrome (IBS), yet specific pathophysiological mechanisms remain unclear. We showed that decreasing intake of fermentable carbohydrates improved abdominal pain in patients with IBS, and this was accompanied by changes in the gut microbiota and decreased urinary histamine concentrations. Here, we used germ-free mice colonized with fecal microbiota from patients with IBS to investigate the role of gut bacteria and the neuroactive mediator histamine in visceral hypersensitivity. Germ-free mice colonized with the fecal microbiota of patients with IBS who had high but not low urinary histamine developed visceral hyperalgesia and mast cell activation. When these mice were fed a diet with reduced fermentable carbohydrates, the animals showed a decrease in visceral hypersensitivity and mast cell accumulation in the colon. We observed that the fecal microbiota from patients with IBS with high but not low urinary histamine produced large amounts of histamine in vitro. We identified Klebsiella aerogenes, carrying a histidine decarboxylase gene variant, as a major producer of this histamine. This bacterial strain was highly abundant in the fecal microbiota of three independent cohorts of patients with IBS compared with healthy individuals. Pharmacological blockade of the histamine 4 receptor in vivo inhibited visceral hypersensitivity and decreased mast cell accumulation in the colon of germ-free mice colonized with the high histamine-producing IBS fecal microbiota. These results suggest that therapeutic strategies directed against bacterial histamine could help treat visceral hyperalgesia in a subset of patients with IBS with chronic abdominal pain.

Gut bacteria interact directly with colonic mast cells in a humanized mouse model of IBS.

Both mast cells and microbiota play important roles in the pathogenesis of Irritable Bowel Syndrome (IBS), however the precise mechanisms are unknown. Using microbiota-humanized IBS mouse model, we show that colonic mast cells and mast cells co-localized with neurons were higher in mice colonized with IBS microbiota compared with those with healthy control (HC) microbiota. In situ hybridization showed presence of IBS, but not control microbiota, in the lamina propria and RNAscope demonstrated frequent co-localization of IBS bacteria and mast cells. TLR4 and H4 receptor expression was higher in mice with IBS microbiota, and in peritoneal-derived and bone marrow-derived mast cells (BMMCs) stimulated with IBS bacterial supernatant, which also increased BMMCs degranulation, chemotaxis, adherence and histamine release. While both TLR4 and H4 receptor inhibitors prevented BMMCs degranulation, only the latter attenuated their chemotaxis. We provide novel insights into the mechanisms, which contribute to gut dysfunction and visceral hypersensitivity in IBS.

Pregnancy-Associated Pelvic Floor Health Knowledge and Reduction of Symptoms: The PREPARED Randomized Controlled Trial.

OBJECTIVES: Pregnancy and childbirth can lead to pelvic floor disorders, yet this topic is not routine in antenatal education. We aimed to determine the impact of a pregnancy workshop on women's postpartum pelvic floor health knowledge, performance of pelvic floor muscle exercises (PFME), symptoms, condition-specific quality of life, mode of delivery, and satisfaction. METHODS: This was a RCT. Pregnant primiparous women in a tertiary care centre received a pelvic floor health workshop intervention versus routine prenatal care. Thirty-six participants/group were needed to detect a significant knowledge difference (power = 0.80, α = 0.05). Participants completed questionnaires at recruitment and six weeks postpartum. Main outcome measures were: difference between groups in knowledge scores; PFME-specific knowledge and practice; pelvic symptoms and condition-specific quality of life; and mode of and satisfaction with delivery. RESULTS: Fifty women were recruited per group; 40 attended the workshop. Women were Caucasian (72%), college educated (96%), mean age 33.2. Mean demographics did not differ. Postpartum data were available for 37 women per group. The intervention group scored higher on a pelvic floor knowledge questionnaire (mean score 31.2/39 vs. 29.3/39, P = 0.02, 95% CI 0.3, 3.6). 58.3% of intervention participants reported daily performance of PFME compared with 22.9% of controls (P = 0.002) and rated higher confidence in correct performance (P = 0.004). The intervention group reported fewer bowel symptoms (P = 0.046). There were no differences in urinary or prolapse symptoms, mode of delivery, complications, or satisfaction. CONCLUSION: A pelvic floor health workshop improves postpartum knowledge, performance of PFME, and bowel-specific quality of life.

Pelvic Floor Health Education: Can a Workshop Enhance Patient Counseling During Pregnancy?

OBJECTIVES: Pelvic floor disorders commonly affect women's quality of life. Their etiology is multifactorial, yet pregnancy and vaginal delivery (VD) are major inciting risk factors. Our objectives were to assess pelvic floor health information given by maternity providers to their pregnant patients, to create a pelvic floor health information workshop, and to determine its impact on women's preferences for mode of delivery. METHODS: This descriptive study recruited primiparous women with a singleton gestation at St Paul's Hospital in Vancouver, Canada. Participants received a 2-hour workshop describing pelvic floor disorders and pregnancy, modes of delivery, as well as strategies for maintaining pelvic floor health and preventing disease. Women completed questionnaires assessing baseline knowledge and level of comfort with different modes of delivery before and after the workshop. RESULTS: Forty participants completed the workshop. Seventy percent had an obstetrician, 20% had a midwife, and 10% had a family physician. Five percent of the participants reported receiving information regarding pelvic organ prolapse as well as urinary and fecal incontinence. The workshop did not influence women's preferred mode of delivery, including VD (P = 1.00), forceps-assisted VD (P = 0.48), vacuum-assisted VD (P = 0.68), postlabor cesarean delivery (P = 0.32), and elective cesarean delivery (P = 0.86). CONCLUSIONS: Current antenatal care is lacking in the area of pelvic floor health education. Patient counseling can be enhanced via a standard workshop. Concerns about negatively influencing women's preferences for mode of delivery are unwarranted, as the pelvic floor health workshop, given during pregnancy, did not significantly change participants' preferences.