Agnès Mogenet

Effects of orally administered Lactobacillus casei DN-114 001 on the composition or activities of the dominant faecal microbiota in healthy humans

The composition and activities of the faecal microbiota in twelve healthy subjects analysed in a single open study were monitored before (1-week baseline step), during (10 d supplementation step) and after (10 d follow-up step) the ingestion of a fermented milk containing Lactobacillus casei DN-114 001. Fluorescent in situ hybridisation with group-specific DNA probes, real-time PCR using L. paracasei group-specific primers and temporal temperature gradient gel electrophoresis (TTGE) using group-specific primers were carried out, together with bacterial enzyme activity and metabolite analyses to monitor the structure and activities of the faecal microbiota. L. casei DNA was detected in the faeces of all of the subjects by TTGE after 10 d supplementation. Its quantification by real-time PCR showed a 1000-fold increase during the test step compared with initial levels. No major modification in either the dominant members of the faecal microbiota or their activities was observed during the trial. In conclusion, the short-term consumption of a milk product containing L. casei DN-114 001 was accompanied by a high, transient increase in the quantity of this strain in the faeces of all of the subjects without markedly affecting biochemical or bacteriological factors.

Survival of Lactobacillus casei in the human digestive tract after consumption of fermented milk.

ABSTRACT A human trial was carried out to assess the ileal and fecal survival of Lactobacillus casei DN-114 001 ingested in fermented milk. Survival rates were up to 51.2% in the ileum and 28.4% in the feces. The probiotic bacterium has the capacity to survive during its transit through the human gut.

Effect of Hydrochlorothiazide on Urinary Calcium Excretion in Dent Disease: An Uncontrolled Trial

BACKGROUND Thiazide doses equivalent to 1 to 2 mg/kg/d of hydrochlorothiazide (HCTZ) have been proposed to correct hypercalciuria and prevent kidney failure in patients with Dent disease. However, they can cause adverse metabolic effects in the long term. In treating hypertension in children, lower thiazide doses have been shown to be as effective and well tolerated. STUDY DESIGN Uncontrolled trial, with forced-titration sequential open-label study design. SETTING & PARTICIPANTS 7 boys with genetically confirmed Dent disease and mild phenotype (neither overt sodium wasting nor kidney failure). INTERVENTION After a 1-month run-in period, patients sequentially received amiloride (5 mg/d) alone (1 month) and then for 3 periods of 2 months in association with increasing doses of HCTZ (<0.2, 0.2 to 0.4, and 0.4 to 0.8 mg/kg/d). OUTCOMES Urinary calcium excretion and extracellular volume indicators. MEASUREMENTS At the end of each period, 2 daily 24-hour urinary collections were performed on the days preceding admission. Blood and spot urine samples also were collected. RESULTS A greater HCTZ dose increased renin, aldosterone, and plasma protein concentrations. Amiloride alone had no effect on calcium excretion. The greatest HCTZ doses decreased spot urinary calcium excretion by 42% compared with baseline (median, 0.3; minimum, maximum, 0.2, 0.8 versus median, 0.8; minimum, maximum, 0.4, 1.1, respectively; P = 0.03). However, patients developed adverse reactions, including muscle cramps (n = 2), biological (n = 7) or symptomatic hypovolemia (n = 1), hypokalemia (n = 4), and hyponatremia (n = 1), which all corrected after treatment withdrawal. LIMITATION Small sample size and absence of a control group. CONCLUSION HCTZ doses greater than 0.4 mg/kg/d decreased calcium excretion, but were associated with significant adverse events. Thiazide diuretic therapy should be considered with caution in children with Dent disease.

Survival of Bifidobacterium animalis DN-173 010 in the Faecal Microbiota after Administration in Lyophilised Form or in Fermented Product – A Randomised Study in Healthy Adults

The survival of Bifidobacterium animalis strain DN-173 010 was assessed after its ingestion in a fermented product or in a lyophilised form. Twelve healthy subjects were included in a randomised, open study with 2 parallel groups. The composition and activities of the faecal microbiota were monitored before (10-day baseline step), during (1-week product administration step) and after (10-day follow-up step) the ingestion of 1 of the 2 products. A colony immunoblotting method, fluorescent in situ hybridisation with group-specific DNA probes, and temporal temperature gradient gel electrophoresis using group-specific primers were carried out to compare survival of B. animalis strain DN-173 010 after ingestion of the 2 products, together with analyses of enzyme activities and faecal metabolites. At the end of the supplementation step, the mean number of B. animalis DN-173 010 quantified by immunodetection in the faeces of 5 of 6 subjects in each treatment group was ≧108 colony-forming units/g faeces. These numbers corresponded to an average survival of 22% for the lyophilised form and 20% for the fermented product. At the same step, the PCR temporal temperature gradient gel electrophoresis profiles showed a double band corresponding to the B. animalis DN-173 010 pattern for 11 subjects. No major modification was observed during the trial in either the dominant members of the faecal microbiota assessed by fluorescent in situ hybridisation or their activities. In conclusion, we show that the lyophilised form of B. animalis DN-173 010 survives transit and could represent a more convenient form to administer for long-term clinical trials.

Lactobacillus rhamnosus R11 Consumed in a Food Supplement Survived Human Digestive Transit without Modifying Microbiota Equilibrium as Assessed by Real-Time Polymerase Chain Reaction

The aim of this study was to evaluate the survival of Lactobacillus rhamnosus R11 and Lactobacillus acidophilus R52 in the human digestive tract and their effects on the microbiota homeostasis. We designed an open human trial including 14 healthy volunteers. A 3-week exclusion period of fermented products was followed by a 12-day consumption period of 4 capsules daily containing 2 × 109L. rhamnosus R11 and 1 × 108L. acidophilus R52, and a 12-day wash-out period. The 2 strains and dominant bacterial groups of the microbiota were quantified by real-time polymerase chain reaction. At the end of the capsule consumption period, high levels of L. rhamnosus R11 were detected in faecal samples from all volunteers, reaching a mean value of 7.1 log10 colony-forming unit (CFU) equivalents/g of stool. L. acidophilus R52 was detected in the stools of only 1 volunteer, reaching a maximum level of 6.1 log10 CFU equivalents/g of stool. Dilution plating enumerations performed in parallel provided less consistent and generally lower levels. No significant effect of capsule consumption was observed on microbiota homeostasis for the dominant faecal populations. Mean values of 8.8, 9.2, 9.9 and 10.6 log10 CFU equivalents/g of stool were obtained for the Clostridium coccoides, Bifidobacterium sp., Bacteroides sp. and Clostridium leptum groups, respectively.

Polymorphisms of coding trinucleotide repeats of homeogenes in neurodevelopmental psychiatric disorders.

Objectives Autism (MIM♯209850) and schizophrenia (MIM♯181500) are both neurodevelopmental psychiatric disorders characterized by a highly genetic component. Homeogenes and forkhead genes encode transcription factors, which have been involved in brain development and cell differentiation. Thus, they are relevant candidate genes for psychiatric disorders. Genetic studies have reported an association between autism and DLX2, HOXA1, EN2, ARX, and FOXP2 genes whereas only three studies of EN2, OTX2, and FOXP2 were performed on schizophrenia. Interestingly, most of these candidate genes contain trinucleotide repeats coding for polyamino acid stretch in which instability can be the cause of neurodevelopmental disorders. Our goal was to identify variations of coding trinucleotide repeats in schizophrenia, autism, and idiopathic mental retardation. Methods We screened the coding trinucleotide repeats of OTX1, EN1, DLX2, HOXA1, and FOXP2 genes in populations suffering from schizophrenia (247 patients), autism (98 patients), and idiopathic mental retardation (56 patients), and compared them with control populations (112 super controls and 202 healthy controls). Results Novel deletions and insertions of coding trinucleotide repeats were found in the DLX2, HOXA1, and FOXP2 genes. Most of these variations were detected in controls and no difference in their distribution was observed between patient and control groups. Two different polymorphisms in FOXP2 were, however, found only in autistic patients and the functional consequences of these variations of repeats have to be characterized and correlated to particular clinical features. Conclusion This study did not identify specific disease risk variants of trinucleotide repeats in OTX1, EN1, DLX2, HOXA1, and FOXP2 candidate genes in neurodevelopmental psychiatric disorders.