Background The gut-brain axis and the intestinal microbiota are emerging as key players in health and disease. Shifts in intestinal microbiota composition affect a variety of systems; however, evidence of their direct impact on cognitive functions is still lacking. We tested whether faecal microbiota transplant (FMT) from aged donor mice into young adult recipients altered the hippocampus, an area of the central nervous system (CNS) known to be affected by the ageing process and related functions. Results Young adult mice were transplanted with the microbiota from either aged or age-matched donor mice. Following transplantation, characterization of the microbiotas and metabolomics profiles along with a battery of cognitive and behavioural tests were performed. Label-free quantitative proteomics was employed to monitor protein expression in the hippocampus of the recipients. We report that FMT from aged donors led to impaired spatial learning and memory in young adult recipients, whereas anxiety, explorative behaviour and locomotor activity remained unaffected. This was paralleled by altered expression of proteins involved in synaptic plasticity and neurotransmission in the hippocampus. Also, a strong reduction of bacteria associated with short-chain fatty acids (SCFAs) production (Lachnospiraceae, Faecalibaculum, and Ruminococcaceae) and disorders of the CNS (Prevotellaceae and Ruminococcaceae) was observed. Finally, the detrimental effect of FMT from aged donors on the CNS was confirmed by the observation that microglia cells of the hippocampus fimbria, acquired an ageing-like phenotype; on the contrary, gut permeability and levels of systemic and local (hippocampus) cytokines were not affected. Conclusion These results demonstrate that age-associated shifts of the microbiota have an impact on protein expression and key functions of the CNS. Furthermore, these results highlight the paramount importance of the gut-brain axis in ageing and provide a strong rationale to devise therapies aiming to restore a young-like microbiota to improve cognitive functions and the declining quality of life in the elderly.

Background. The gut-brain axis and the intestinal microbiota are emerging as key players in health and disease. Shifts in intestinal microbiota composition affect a variety of systems, however, evidence of their direct impact on cognitive functions is still lacking. We tested whether faecal microbiota transplant (FMT) from aged donor mice into young adult recipients affected the hippocampus, an area of the central nervous system (CNS) known to be affected by the ageing process, and related functions. Methods and Findings.Young adult mice were transplanted with the microbiota from either aged or age-matched donor mice. Following transplantation, characterization of the microbiotas and metabolomics profiles along with a battery of cognitive and behavioural tests were performed. Label-free quantitative proteomics was employed to monitor protein expression in the hippocampus of the recipients. Gut permeability, levels of circulating cytokines and expression of markers of microglia cells were also assessed. FMT from aged donors led to impaired spatial learning and memory in young adult recipients, whereas anxiety, explorative behaviour and locomotor activity remained unaffected. This was paralleled by altered expression of proteins involved in synaptic plasticity and neurotransmission in the hippocampus. Also, a strong reduction of bacteria associated with short-chain fatty acids (SCFAs) production (Lachnospiraceae, Faecalibaculum, and Ruminococcaceae) and disorders of the CNS (Prevotellaceae and Ruminococcaceae) was observed. Finally, microglia cells of the hippocampus fimbria, acquired an ageing-like phenotype, while gut permeability and levels of circulating cytokines remained unaffected. Conclusions.These results demonstrate a direct effect of the age-associated shifts of the microbiota on protein expression and key functions of the central nervous system. Furthermore, these results additionally highlight the paramount importance of the gut-brain axis in ageing and provide a strong rationale to devise therapies aiming to restore a younglike microbiota to improve cognitive functions in the elderly.

Background: Breast cancer is the second most prevalent cancer worldwide with around 1.7 million new cases diagnosed every year. Whilst prognosis is generally favourable in early stages, this worsens significantly in advanced disease. Therefore, it is pertinent to focus on mitigating factors that may slow growth or progression. Recently, the gut microbiome has been implicated in a wide-range of roles in tumour biology. Through modulation of immunity, the gut microbiota can improve the efficacy of several immunotherapies. However, despite the prevalence of breast cancer, there is still a lack of microbiota studies in this field, including exploring the influence of external microbiome-modulating factors such as antibiotics. We describe herein how disruption of the gut microbiota via antibiotics may be detrimental to patient outcomes through acceleration of tumour growth. Results:Supplementing animals with a cocktail of antibiotics leads to gut microbiota alterations and is accompanied by significant acceleration of tumour growth. Surprisingly, and distinct from previous microbiome-tumour studies, the mechanism driving these effects do not appear to be due to gross immunological changes. Analysis of intratumoural immune cell populations and cytokine production are not affected by antibiotic administration. Through global tumour transcriptomics, we have uncovered dysregulated gene expression networks relating to protein and lipid metabolism that are correlated with accelerated tumour growth.Fecal metabolomics revealed a reduction of the microbial-derived short-chain fatty acid butyrate that may contribute to accelerated tumour growth. Finally, through use of a routinely administered antibiotic in breast cancer patients, Cephalexin, we have shown that tumour growth is also significantly affected. Metataxanomic sequencing and analysis highlighted significant antibiotic-associated reductions in the butyrate producing genera Odoribacter and Anaeotruncus, and increased abundance of Bacteroides. Conclusions:Our data indicate that perturbation of the microbiota by antibiotics may have negative impacts on breast cancer patient outcomes. This is of importance as antibiotics are regularly prescribed to breast cancer patients undergoing mastectomy or breast reconstruction. We have also shown that the metabolic impact of disruption to the microbiome should be considered alongside the potent immunological effects. We believe our work lays the foundation for improving the use of antibiotics in patients, and with further investigation could potentially inform clinical practice.

AbstractThe gut microbiota plays a crucial role in regulating and maintaining the epithelial barrier, particularly during early life. Notably, patients with chronic intestinal inflammation have a dysregulated process of renewal and replenishment of the intestinal epithelial cell (IEC) barrier, which is linked to disturbances in the gut microbiota. To date, there are no studies focussed on understanding the impact of inflammatory cell shedding events during the early life developmental window, and which host and microbial factors mediate these responses. Here we sought to determine pathological cell shedding outcomes throughout the postnatal developmental period (day 14, 21, 29 and week 8). Surprisingly neonatal mice (day 14 and 21) were highly refractory to induction of cell shedding after intraperitoneal administration of LPS, with day 29 mice showing strong pathological responses, more similar to those observed in adult mice. These differential responses were not linked to defects in the cellular mechanisms and pathways known to regulate cell shedding responses, although we did observe that neonatal mice had elevated anti-inflammatory (IL-10) responses. Notably, when we profiled microbiota and metabolites from these mice, we observed significant alterations. Neonatal mice had high relative abundances of Streptococcus, Escherichia and Enterococcus and increased primary bile acids. In contrast, older mice were dominated by Candidatus Arthromitus, Alistipes and Lachnoclostridium, and had increased concentrations of SCFAs and methyamines. Faecal microbiota transplant (FMT) and antibiotic studies confirmed the importance of early life gut microbiota in cell shedding responses. In these studies, neonates treated with antibiotics restored LPS-induced small intestinal cell shedding, whereas adult FMT alone had no effect. Our findings further support the importance of the early life window for microbiota-epithelial interactions in the presence of inflammatory stimuli and highlight areas for further investigation to probe underlying mechanisms to drive therapeutic development within the context of chronic inflammatory intestinal diseases.

Chronic kidney disease is linked to impaired cognitive function and increased neurovascular disease risk even after correction for classical risk factors. The mechanism(s) underlying these links are unclear but may involve interactions of uraemic toxins with the blood-brain barrier (BBB). Here, we studied how the major uraemic toxinp-cresol sulfate (pCS) could affect BBB integrity. Exposure of human hCMEC/D3 endothelial cells to pCS dose-dependently increased paracellular permeability and disrupted intercellular tight junctions, a permeabilising effect mirrored in mice. Whole brain RNAseq analysis identified pCS-mediated suppression of neuronal activity, transcription and mitochondrial respiration pathways.In vitrostudies identified pCS binding to the epidermal growth factor receptor (EGFR), leadingviaannexin A1 and STAT3 signalling to mobilisation of matrix metalloproteinase (MMP)-2/9. Confirming this pathwayin vivo, the BBB damaging effects of pCS were prevented by pre-treatment with the EGFR antagonist erlotinib or the MMP2/9 inhibitor SB-3CT. Finally, hCMEC/D3 cells exposed to haemodialysis patient serum, but not to that of healthy donors, showed an erlotinib-sensitive increase in paracellular permeability that closely correlated in size to the total serum pCS content. Overall, we define a pathway linking the uraemic toxin pCS with BBB damage suggesting that targeting the EGFR may be useful in mitigating against cerebrovascular damage in chronic kidney disease.Translational StatementPatients with chronic kidney disease (CKD) have increased risk of cognitive impairment and stroke, pathologies associated cerebromicrovascular disease, but it is not clear why. Here, we show that the uraemic toxin p-cresol sulfate impairs BBB functionin vitroandin vivothrough EGFR-dependent MMP mobilisation. Importantly, serum from haemodialysis patients can also impair permeability of anin vitroBBB model, an effect prevented by EGFR inhibition, and proportional in magnitude to serum pCS content. Our data suggest that existing EGFR inhibitory drugs might have utility in preventing cerebral small vessel disease in CKD patients.

No abstract

Bronchial provocation tests using aerosols in laboratory animals are difficult to standardize and quantify, because the amount of drug actually reaching the airways is unknown. To improve the quantification of aerosolized inhaled stimuli, we designed an apparatus that allows, in anesthetized intubated ventilated animals, control of temperature and hygrometry of inspired air, computerized measurement of pulmonary resistance, and fully automated delivery of a known amount of aerosolized drug directly into the trachea. Calibration of the aerosol delivery involved direct measurement of liquid delivered at the tip of the tracheal cannula. Despite all our efforts at standardization and full automation of all steps, reproducibility of aerosol delivery was poor, with stroke-by-stroke differences of 26 or 42%, according to whether an air-jet or an ultrasonic nebulizer was used. Histamine dose-response curves performed in 15 guinea pigs with this device confirmed marked differences among animals and also disclosed large intraindividual changes in bronchial responsiveness.

Treatment of anxiety and depression predominantly centres around pharmacological interventions, which have faced criticism for their associated side effects, lack of efficacy and low tolerability. Saffron, which is reportedly well...