Role of gut microbiota in pathogenesis of selected chronic diseases

The human digestive system is colonized by a huge number of microorganisms, that are referred to collectively as the gut microbiota. The composition of intestinal microorganisms are shaped from an early life and undergoes constant changes depending on the influence of external factors, such as: type of delivery, feeding the young child, diet in subsequent years of life, pharmaceuticals use, stress, lifestyle or infections and previous inflammation within the digestive tract. Despite transient changes in microbiota composition, the intestinal ecosystem is constantly striving to maintain homeostasis, both qualitative and quantitative, which is fundamental to human health and human development. Microbes present in the intestines are responsible for sealing the intestinal barrier, mucin production, stimulation of the angiogenesis process, supporting digestive processes by fermentation and decomposition of undigested food residues, vitamin production or protection from pathogenic microorganisms. As shown by numerous studies carried out in recent years, intestinal dysbiosis plays a fundamental role in the development of many chronic diseases such as inflammatory bowel disease, diabetes, obesity, celiac disease, connective tissue diseases and others. Insightful understanding of the interactions between microorganisms and the host organisms can provide new information about pathogenesis of diseases as well as new ways to prevent and treat intestinal or systemic disorders. The aim of this work is to review the latest reports on the role of the gastrointestinal microbiome in selected chronic diseases

The dynamics of vaginal and rectal Lactobacillus spp. flora in subsequent trimesters of pregnancy in healthy Polish women, assessed using the Sanger sequencing method

Background Lactobacilli play an important role in maintaining vaginal health and protection against bacterial infections in the genital tract. The aim of this study is to show the dynamics of changes of the vaginal and rectal Lactobacillus flora during pregnancy by using the Sanger sequencing method. Method The study included 31 healthy pregnant women without clinical signs of genitourinary infections. The material was taken in the three trimesters of pregnancy by vaginal and rectal swabs and grown on the MRS agar quantitatively to estimate the number of Lactobacillus spp. [CFU/ml]. Afterwards, 3 to 8 morphologically different lactobacilli colonies were taken for identification. Bacterial species identification was performed by 16 s rDNA sequence fragment analyses using the Sanger method. Results Among the patients tested, the most common species colonizing the vagina in the first trimester were: L. crispatus 29%, L. gasseri 19.4% and L. rhamnosus 16.1%, in the second trimester: L. crispatus 51.6%, L. gasseri 25.8%, L. rhamnosus 19.4% and L. amylovorus 16.1%, and in the third trimester the most common Lactobacillus species were: L. crispatus 25.8%, L. gasseri 25.8% and L. johnsonii 19.4%. In rectal species, the number decreased in the second and third trimesters in comparison to the first trimester (p = 0.003). An analysis of rectal dynamics showed that in the first trimester, the most common species were: L. johnsonii 19.4%, and L. plantarum 9.7%, in the second trimester: L. crispatus 9.7% and L. mucosae 6.5%, and in the third trimester: L. casei 9.7% and L. rhamnosus 9.7%. Individual dynamics of the Lactobacillus species composition showed variability, characterized by continuous, intermittent, or periodic colonization. The patients examined were mostly colonized by three Lactobacillus species in vagina (32.3%), whereas for the rectum, one Lactobacillus species during the whole pregnancy duration was common (32.3%). Conclusion This study showed that in the examined group of healthy, pregnant Polish women, the vaginal Lactobacillus flora, both qualitative and quantitative, was stable during the three subsequent trimesters. In contrast, the number of rectal Lactobacillus species dramatically decreased after the first trimester

The effect of linagliptin treatment on gut microbiota in patients with HNF1A-MODY or type 2 diabetes : a preliminary cohort study

Wstęp: W wielu dotychczas przeprowadzonych badaniach oceniano związek między cukrzycą a mikroflorą jelitową. Obserwowano zmianę mikroflory jelitowej pod wpływem inhibitorów dipeptydylopeptydazy-4 w modelach zwierzęcych. Celem niniejszego badania była ocena wpływu linagliptyny na florę bakteryjną okrężnicy u ludzi. Materiał i metody: W prospektywnym badaniu kohortowym wzięło udział 24 pacjentów: 5 chorych na cukrzycę monogenową, związaną z mutacją HNF1A, i 19 chorych na cukrzycę typu 2. Próbki kału pobrano przed i 4 tygodnie po intensyfikacji aktualnego leczenia za pomocą linagliptyny lub pochodnej sulfonylomocznika. Z próbek kału wyizolowano rRNA, a następnie wykonano sekwencjonowanie 16S nowej generacji. Wyniki: U 9 pacjentów do leczenia dołączono linagliptynę, a u 15 pacjentów dołączono sulfonylomocznik lub zwiększono jego dawkę. Po leczeniu linagliptyną nie zaobserwowano zmian na poziomach taksonomicznych L2–L7 na podstawie analizy składu mikrobiomów (ANCOM). To samo odnosiło się do różnorodności alfa [wskaźnik różnorodności Shannona, p = 0,59; wskaźnik równomierności Pielou, p = 0,68; obserwowane operacyjne jednostki taksonomiczne (OTU), p = 0,77] i różnorodności beta (nieważony wskaźnik UniFrac, p = 0,99; ważony wskaźnik UniFrac, p = 0,93; wskaźnik Braya–Curtisa, p = 0,98; wskaźnik Jaccarda, p = 0,99). Również po intensyfikacji leczenia pochodną sulfonylomocznika nie zaobserwowano zmian na poziomach taksonomicznych L2–L7 w ANCOM ani zmian w różnorodności alfa (wskaźnik różnorodności Shannona, p = 0,19; wskaźnik równomierności Pielou, p = 0,21; obserwowane OTU, p = 0,42) i różnorodności beta (nieważony wskaźnik UniFrac, p = 0,99; ważony wskaźnik UniFrac, p = 0,99; wskaźnik Braya–Curtisa, p = 1; wskaźnik Jaccarda, p = 0,99). Wnioski: Po 4 tygodniach od dołączenia linagliptyny do aktualnego leczenia cukrzycy nie zaobserwowano zmian w mikroflorze okrężnicy. Konieczne są dalsze badania w celu ustalenia, czy linagliptyna wpływa na mikroflorę okrężnicy u ludzi.Introduction. Many studies have evaluated the relationship between diabetes and microbiota. In animal models, the dipeptidyl peptidase-4 inhibitors altered the gut microbiota. We investigated whether linagliptin alters the gastrointestinal flora in humans. Materials and methods. This prospective cohort study enrolled 24 patients: 5 patients with maturity onset diabetes of the young associated with HNF1A mutation and 19 patients with type 2 diabetes mellitus. Stool samples were collected at baseline and 4 weeks after treatment intensification with either linagliptin or a sulphonylurea alongside current treatment. Faecal 16S rRNA was analysed by next-generation sequencing. Results. Nine patients initiated linagliptin whereas 15 patients initiated or increased the dose of a sulphonylurea. After linagliptin treatment, we did not observe changes in taxa in L2–L7 based on analysis of composition of microbiomes (ANCOM). The same held true for pairwise alpha diversity (Shannon diversity, p = 0.59; Pielou’s measure of evenness, p = 0.68; and observed operational taxonomic units [OTUs], p = 0.77) and beta diversity distances (unweighted UniFrac, p = 0.99; weighted UniFrac, p = 0.93; Bray-Curtis, p = 0.98; and Jaccard, p = 0.99). Similarly, after sulphonylurea intensification, we did not observe changes in taxa in L2–L7 in ANCOM, nor were there changes in alpha diversity (Shannon diversity, p = 0.19; Pielou’s measure of evenness, p = 0.21; and observed OTUs, p = 0.42) or beta diversity distances (unweighted UniFrac, p = 0.99; weighted UniFrac, p = 0.99; Bray-Curtis, p = 1; and Jaccard, p = 0.99). Conclusion. We did not observe changes in colonic microbiota 4 weeks after addition of linagliptin to current diabetes treatment. Further studies are required to determine whether linagliptin influences the colonic microbiota in human

The application of genetics methods to differentiation of three Lactobacillus species of human origin

In recent decades, the interest in probiotics as diet supplements or drugs has increased. In order to determine a specific bacterial isolate to be probiotic, it is necessary to describe precisely its probiotic characteristics and taxonomic properties, including the strain level. Most of the well-known genotyping methods were designed for the commonly-found pathogenic bacteria. The objective of this study is to undertake an attempt at standardization of FISH, RAPD and PFGE methods to genotype and identify the bacteria belonging to Lactobacillus fermentum, L. gasseri and L. plantarum species. The FISH probes have been designed and tested for Lactobacillus fermentum, L. gasseri and L. plantarum species and an endeavor has been made at standardization of RAPD and PFGE methods for these bacterial species. Moreover, the MLST method was applied to differentiate Lactobacillus plantarum strains. L. plantarum isolated from humans could not be genetically diversified with the use of RAPD, PFGE or MLST methods; only the strains originating from plants have displayed diversification among themselves and have been different from the strains of human origin

Quantitative evaluation of fungi of the genus Candida in the feces of adult patients with type 1 and 2 diabetes : a pilot study

BACKGROUND: Gastrointestinal tract microbiota, particularly bacterial microflora, seem to have a different qualitative and quantitative composition in both type 1 (T1DM) and type 2 diabetes (T2DM) mellitus cases as compared to non-diabetic individuals. So far, there are no data from diabetes research concerning the prevalence of fungi, particularly the most common genus, i.e. Candida, which are important components of human colon microflora. We aimed to examine whether there are quantitative changes of Candida fungi in the feces of patients with T1DM and T2DM as compared to healthy controls. FINDINGS: Overall, we included 44 diabetic patients (27 patients with T1DM and 17 with T2DM) as well as 17 healthy, non-diabetic controls. Feces and blood samples were collected from all study individuals. DNA was isolated from fecal samples and quantitative real time PCR (qPCR) was applied in order to determine the number of fungal cells. Statistical association with selected clinical and biochemical features was examined. There was a difference in the amount of Candida in the feces among the three examined groups (p = 0.007). Candida spp. populations in T1DM and T2DM subjects were larger as compared to controls (p = 0.017 and p = 0.037, respectively). However, no difference was found between T1DM and T2DM. No association was identified between the quantity of fungi and examined patients’ characteristics, except for negative correlation with blood lipid parameters in T2DM group. CONCLUSIONS: Candida fungi appear to be more prevalent in the feces of patients with T1DM and T2DM. Their amount seems to be associated with serum lipids in T2DM patients. This initial finding requires further confirmation