Effect of daily co-exposure to inulin and chlorpyrifos on selected microbiota endpoints in the SHIME® model

International audienc

Gene expression (mRNA) of markers of intestinal maturation in the ileum and colon of control rats (CPF0, open bars) or CPF-exposed pups ((CPF1, 1 mg/kg/day, grey bars) at weaning (D21) and as young adults (D60), expressed as 2^−DCt.

<p>Values are quoted as the mean ± SEM. D21: CPF0 n = 28, CPF1 n = 24; D60: CPF0 n = 21, CPF1 n = 13. * p<0.05. (A) ZO-1; (B) occludin; (C) claudin1; (D) claudin4.</p

Changes in composition and function of human intestinal microbiota exposed to chlorpyrifos in oil as assessed by the SHIME (R) model

The presence of pesticide residues in food is a public health problem. Exposure to these substances in daily life could have serious effects on the intestine-the first organ to come into contact with food contaminants. The present study investigated the impact of a low dose (1 mg/day in oil) of the pesticide chlorpyrifos (CPF) on the community structure, diversity and metabolic response of the human gut microbiota using the SHIME (R) model (six reactors, representing the different parts of the gastrointestinal tract). The last three reactors (representing the colon) were inoculated with a mixture of feces from human adults. Three time points were studied: immediately before the first dose of CPF, and then after 15 and 30 days of CPF-oil administration. By using conventional bacterial culture and molecular biology methods, we showed that CPF in oil can affect the gut microbiota. It had the greatest effects on counts of culturable bacteria (with an increase in Enterobacteria, Bacteroides spp. and clostridia counts, and a decrease in bifidobacterial counts) and fermentative activity, which were colon-segment-dependent. Our results suggest that: (i) CPF in oil treatment affects the gut microbiota (although there was some discordance between the culture-dependent and culture-independent analyses); (ii) the changes are "SHIME (R)-compartment" specific; and (iii) the changes are associated with minor alterations in the production of short-chain fatty acids and lactate

The time course of the appearance of FITC-dextran in blood (µg/µL) in control rats (CPF0, grey line) or CPF-exposed pups (CPF1, 1 mg/kg/day, black line) at weaning (D21) and as young adults (D60).

<p>Values are quoted as the mean ± SEM. D21: CPF0 n = 12, CPF1 n = 17; D60: CPF0 n = 14, CPF1 n = 13. * p<0.05.</p

Percentage of rats contaminated by bacterial translocation (mean ± SEM) to the spleen at weaning (D21) and as young adults (D60).

<p>Control groups (CPF0, open bars) and CPF-exposed groups (CPF1: 1 mg/kg/day, grey bars). i, p<0.10; * p<0.05; ** p<0.01; *** p<0.001. D21: CPF0 n = 10, CPF1 n = 10; D60: CPF0 n = 10, CPF1 n = 10.</p

Body mass (g) (A) and body length (cm) (B) of control rats (CPF0, open bars) or CPF-exposed pups (CPF1, 1 mg/kg/day, grey bars) at birth (D0), at weaning (D21) and as young adults (D60).

<p>Values are quoted as the mean ± SEM. D0: n = 41, CPF1 n = 37; D21: CPF0 n = 28, CPF1 n = 24; D60: CPF0 n = 21, CPF1 n = 13. ** p<0.01.</p

Immunofluorescent staining of ZO1 in the ileum and colon of CPF-exposed (1 mg/kg/day, CPF1) rats and control (CPF0) rats at weaning (D21) and as young adults (D60). Magnification: x 630.

<p>D21: CPF0 n = 5, CPF1 n = 5; D60: CPF0 n = 5, CPF1 n = 5. ZO-1 detection at D21 and D60 in CPF0rats (panels A and C, respectively) and in CPF1rats (panels, B and D respectively).</p

Freeze-dried fecal samples are biologically active after long-lasting storage and suited to fecal microbiota transplantation in a preclinical murine model ofClostridioides difficileinfection

International audienceFecal microbiota transplantation is now recommended for treating recurrent forms ofClostridioides difficileinfection. Recent studies have reported protocols using capsules of either frozen or freeze-dried stool allowing oral administration in in- and out-patient settings. However, a central question remains the viability, engraftment, and efficacy of the microbiome over time during storage life. This study shows that both the freeze-drying and freezing procedures for fecal samples allowed preserving viability, short-chain fatty acids concentration, and anti-Clostridioides difficileproperties of microbiota without significant alteration after storage for 12 months. Fecal transplantation with freeze-dried microbiota allowed engraftment of microbiota leading to clearance ofClostridioides difficileinfection in a preclinical murine model with a survival rate of 70%versus53-60% in mice treated with frozen inocula, and 20% in the untreated group. Moreover, the freeze-dried powder can be used to fill oral hard capsules using a very low amount (0.5%) of glidant excipient, allowing oral formulation. Altogether, this study showed that freeze-dried inocula can be used for the treatment ofClostridioides difficileinfection with long-lasting stability of the fecal microbiota. This formulation facilitates biobanking and allows the use of hard capsules, an essential step to simplify patient access to treatment

Inulin Supplementation Lowered the Metabolic Defects of Prolonged Exposure to Chlorpyrifos from Gestation to Young Adult Stage in Offspring Rats

<div><p>Increasing evidence indicates that chlorpyrifos (CPF), an organophosphorus insecticide, is involved in metabolic disorders. We assess the hypothesis whether supplementation with prebiotics from gestation to adulthood, through a modulation of microbiota composition and fermentative activity, alleviates CPF induced metabolic disorders of 60 days old offspring. 5 groups of Wistar rats, from gestation until weaning, received two doses of CPF pesticide: 1 mg/kg/day (CPF1) or 3.5 mg/kg/day (CPF3.5) with free access to inulin (10g/L in drinking water). Then male pups received the same treatment as dams. Metabolic profile, leptin sensitivity, insulin receptor (IR) expression in liver, gut microbiota composition and short chain fatty acid composition (SCFAs) in the colon, were analyzed at postnatal day 60 in the offspring (PND 60). CPF3.5 increased offspring’s birth body weight (BW) but decreased BW at PND60. Inulin supplementation restored the BW at PND 60 to control levels. Hyperinsulinemia and decrease in insulin receptor β in liver were seen in CPF1 exposed rats. In contrast, hyperglycemia and decrease in insulin level were found in CPF3.5 rats. Inulin restored the levels of some metabolic parameters in CPF groups to ranges comparable with the controls. The total bacterial population, short chain fatty acid (SCFA) production and butyrate levels were enhanced in CPF groups receiving inulin. Our data indicate that developmental exposure to CPF interferes with metabolism with dose related effects evident at adulthood. By modulating microbiota population and fermentative activity, inulin corrected adult metabolic disorders of rats exposed to CPF during development. Prebiotics supply may be thus considered as a novel nutritional strategy to counteract insulin resistance and diabetes induced by a continuous pesticide exposure.</p></div