What Do Medical Research Studies Tell About Dybiosis In Celiac Disease and/or Gluten Sensitivity?

RESEARCH STUDY SUMMARIES

“Lower bifidobacteria counts in adult patients with celiac disease on a gluten-free diet.” This study investigated the concentration of fecal bifidobacteria (normal gut bacteria) and pH (acid/alkaline level) of patients with celiac disease on gluten-free diet and control subjects in order to identify if the imbalance on fecal microbiota still remain during the treatment of celiac disease and identify the necessity of dietary supplementation with pre- or probiotics. Results suggest that with lower levels of bifidobacteria, celiac patients have an imbalance in the intestinal microbiota, regardless of pH, even while on a gluten-free diet. This fact could favor the pathological process of the disorder.

Feces of 42 healthy subjects and 14 celiac patients were analyzed. The bifidobacteria count in feces was done in selective medium BIM-25. Microscopic analysis of the colonies was performed by Gram stain. The identification of the genus Bifidobacterium was performed by determination of fructose-6-phosphate phosphoketolase. Fecal pH was measured using a pH meter.

The concentration of bifidobacteria per gram of feces was significantly higher in healthy subjects (controls) (2.5 ± 1.5 x107 CFU/g) when compared to celiac patients (1.5 ± 0.63 x108 CFU/g). The fecal pH was not different between celiac patients (7.19 ± 0.521) and controls (7.18 ± 0.522).35

“Duodenal-mucosal bacteria associated with celiac disease in children.” This study aimed to characterize the composition and diversity of the cultivable duodenal mucosa-associated bacteria of celiac disease patients and control children. Duodenal biopsy specimens from patients with active disease on a gluten-containing diet (n = 32), patients with nonactive disease after adherence to a gluten-free diet (n = 17), and controls (n = 8) were homogenized and plated on plate count agar, Wilkins-Chalgren agar, brain heart agar, or yeast, Casitone, and fatty acid agar. The isolates were identified by partial 16S rRNA gene sequencing. Renyi diversity profiles showed the highest diversity values for active celiac disease patients, followed by nonactive celiac disease patients and control individuals.

Members of the phylum Proteobacteria were more abundant in patients with activeceliac disease than in the other child groups, while those of the phylum Firmicutes were less abundant. Members of the familiesEnterobacteriaceae and Staphylococcaceae, particularly the species Klebsiella oxytoca, Staphylococcus epidermidis, and Staphylococcus pasteuri, were more abundant in patients with active disease than in controls. In contrast, members of the family Streptococcaceae were less abundant in patients with active celiac disease than in controls. Furthermore, isolates of the Streptococcus anginosus and Streptococcus mutans groups were more abundant in controls than in both celiac disease patient groups, regardless of inflammation.36

“Intestinal Bacteroides species associated with coeliac disease.” This study seeking to characterize the predominant species of bacterial populations associated with duodenal biopsies of pediatric patients with active and treated coeliac disease found that Bacteroides, Bifidobacterium and lactic acid bacteria populations in the duodenum of Spanish children with typical coeliac disease (active and treated) and controls differ in diversity and species composition.20 biopsy specimens from patients with active coeliac disease, 12 from patients with treated coeliac disease, and eight from age-matched controls were evaluated for comparative purposes. Bacteroides, Bifidobacterium and lactic acid bacteria (LAB) populations were analysed by PCR-denaturing gradient gel electrophoresis using group-specific primers.

RESULTS: Bacteroides diversity was higher in biopsy specimens from controls than in those from patients with active and treated coeliac disease. Bacteroides distasonis, Bacteroides fragilis/Bacteroides thetaiotaomicron, Bacteroides uniformis and Bacteroides ovatus were more abundant in controls than in patients with coeliac disease (p<0.05). Bacteroides vulgatus was more frequently detected in controls than in patients with treatedcoeliac disease (p<0.01). Bacteroides dorei was more common in patients with active coeliac disease than in those with treated coeliac disease and control children (p<0.01). Bifidobacterium diversity was higher in patients with coeliac disease than in controls. Bifidobacterium adolescentis and Bifidobacterium animalis subsp lactis were more prevalent in patients with active celiac disease than in patients with treated coeliac disease and control children.

A higher LAB diversity was found in patients with treated celiac disease and controls than in patients with active celiac disease. Weissella spp and Lactobacillus fermentum were more frequently detected in patients with treated celiac disease than in controls and patients with active celiac disease.37

Imbalances in faecal and duodenal bifidobacterium species composition in active and non-active coeliac disease.” This study investigating the possible relationships between the gut bifidobacteria composition and coeliac disease (CD) in children found reductions in total Bifidobacterium and B. longum populations were associated with both active and non-active CD when compared to controls.

A total of 48 faecal samples (30 and 18 samples from active and no active CD patients, respectively) and 33 duodenal biopsy specimens of CD patients (25 and 8 samples from active and non-active CD patients, respectively) were analysed. Samples (30 faecal samples and 8 biopsies) from a control age-matched group of children were also included for comparative purposes. Gut Bifidobacterium genus and species were analyzed by real-time PCR.

Results: Active and non-active CD patients showed lower numbers of total Bifidobacterium and B. longum species in faeces and duodenal biopsies than controls, and these differences were particularly remarkable between active CD patients and controls. B. catenulatum prevalence was higher in biopsies of controls than in those of active and non-active CD patients, whereas B. dentium prevalence was higher in faeces of non-active CD patients than in controls. Correlations between levels of Bifidobacteriumand B. longum species in faecal and biopsy samples were detected in both CD patients and controls.38

“Bacterial antigens alone can influence intestinal barrier integrity, but live bacteria are required for initiation of intestinal inflammation and injury.” This study in mice investigating whether live fecal bacteria were necessary for the initiation of an inflammatory responseor whether sterile fecal material w ould provoke a similar response found that while both dead and live bacteria provoke inflammation, only live fecal bacteria initiated mucosal inflammation and injury and a systemic immune response. Fecal bacterial antigens in the presence of live bacteria and sterile fecal bacterial antigens have different effects on the initiation and perpetuation of intestinal inflammation.

Three preparations of fecal material were prepared: (1) a slurry of live fecal bacteria, (2) a sterile lysate of bacterial antigens, and (3) a sterile filtrate of fecal water. Each preparation was introduced via gastric gavage into the intestines of axenic interleukin-10 gene-deficient mice genetically predisposed to develop inflammatory bowel disease. Intestinal barrier integrity and degrees of mucosal and systemic inflammations were determined for each preparation group.

Intestinal barrier integrity, as determined by mannitol transmural flux, was altered by both live fecal bacterial and sterile lysates of bacterial antigens, although it was not altered by sterile filtrates of fecal water.39

“Human milk is a source of lactic acid bacteria for the infant gut.” This study investigating whether human breast milk contains potentially probiotic lactic acid bacteria, and therefore, whether it can be considered a synbiotic food found that Breast-feeding can be a significant source of lactic acid bacteria to the infant gut. Lactic acid bacteria present in milk may have an endogenous origin and may not be the result of contamination from the surrounding breast skin.

Lactic acid bacteria were isolated from milk, mammary areola, and breast skin of eight healthy mothers and oral swabs and feces of their respective breast-fed infants. Some isolates (178 from each mother and newborn pair) were randomly selected and submitted to randomly amplified polymorphic DNA (RAPD) polymerase chain reaction analysis, and those that displayed identical RAPD patterns were identified by 16S rDNA sequencing.

RESULTS: Within each mother and newborn pair, some rod-shaped lactic acid bacteria isolated from mammary areola, breast milk, and infant oral swabs and feces displayed identical RAPD profiles. All of them, independently from the mother and child pair, were identified as Lactobacillus gasseri. Similarly, among coccoid lactic acid bacteria from these different sources, some shared an identical RAPD pattern and were identified as Enterococcus faecium. In contrast, none of the lactic acid bacteria isolated from breast skin shared RAPD profiles with lactic acid bacteria of the other sources.40