Lifestyle of Lactobacillus plantarum in the mouse caecum.

Lactobacillus plantarum is a common inhabitant of mammalian gastrointestinal tracts. Strains of L. plantarum are also marketed as probiotics intended to confer beneficial health effects upon delivery to the human gut. To understand how L. plantarum adapts to its gut habitat, we used whole genome transcriptional profiling to characterize the transcriptome of strain WCFS1 during colonization of the caeca of adult germ-free C57Bl/6 J mice fed a standard low-fat rodent chow diet rich in complex plant polysaccharides or a prototypic Western diet high in simple sugars and fat. Lactobacillus plantarum colonized the digestive tracts of these animals to high levels, although L. plantarum was found in 10-fold higher amounts in the caeca of mice fed the standard chow. Metabolic reconstructions based on the transcriptional data sets revealed that genes involved in carbohydrate transport and metabolism form the principal functional group that is upregulated in vivo compared with exponential phase cells grown in three different culture media, and that a Western diet provides a more nutritionally restricted, growth limiting milieu for the microbe in the distal gut. A set of bacterial genes encoding cell surface-related functions were differentially regulated in both groups of mice. This set included downregulated genes required for the d-alanylation of lipoteichoic acids, extracellular structures of L. plantarum that mediate interactions with the host immune system. These results, obtained in a reductionist gnotobiotic mouse model of the gut ecosystem, provide insights about the niches (professions) of this lactic acid bacterium, and a context for systematically testing features that affect epithelial and immune cell responses to this organism in the digestive tract.

DNA microarray analysis for human congenital heart disease.

Right ventricular hypertrophy and failure are prominent features in cyanotic congenital heart disease, tetralogy of Fallot (TF). Patients with TF require primary cardiac surgery at a very young age. To gain insight into the underlying molecular mechanisms of right ventricular hypertrophy and to identify gene(s) involved in TF, differential gene expression profile was assessed using expression-based microarray technology on right ventricular biopsies from young TF patients who underwent primary correction. By using quantitative immuno histochemistry, expression of vascular endothelial growth factor (VEGF), flk-1, and extracellular matrix (ECM) proteins (collagens and fibronectin) as well as vessel counts and myocyte cell size was evaluated in TF patients in relation to age-matched controls. Among 236 genes showing altered expression pattern in TF patients, VEGF (1.8-fold) and ECM markers were clearly upregulated (fibronectin, 2.4-fold; collagen Ialpha, 7.5-fold; and collagen III, 4.4-fold); flk-1 and most matrix metalloproteinases (MMPs) remained unchanged, except the levels of MMP-13 and -17 declined. Tissue inhibitors of metalloproteinases showed a downregulated pattern. Staining of VEGF in cardiomyocytes and of ECM proteins (fibronectin, collagen I and III) in interstitial as well as in perivascular area was increased (p < 0.01) in TF patients. Morphometric analysis revealed enhanced vascular density (p < 0.05) with unchanged wall thickness and enlarged myocyte cross-sectional areas (p < 0.01) with linear correlation (p < 0.01) with the age in TF-1 patients. We conclude that the upregulation of genes encoding VEGF and ECM proteins are the key events contributing to right ventricular hypertrophy and stunted angiogenesis in patients with TF.

DNA microarray and quantitative analysis reveal enhanced myocardial VEGF expression with stunted angiogenesis in human tetralogy of Fallot.

Tetralogy of Fallot (ToF) is a cyanotic congenital heart disease with prominent right ventricular hypertrophy (RVH) associated with impaired myocardial oxygen and nutrient supply. Consequently, the right ventricle may manifest in altered molecular phenotype with a number of adaptive and inherited gene profiles which are largely unknown. The aim of the present study was to investigate the myocardial differential gene expression profile and to assess myocardial vascularisation in patients with ToF. DNA microarray analysis on right ventricular biopsies from ToF-patients operated for primary corrective surgery (referred as ToF-1; n = 12, mean age 0.5 year) and age matched controls (n = 6) was validated by Northern hybridisation and RT-PCR. Employing immunohistochemistry and video image analysis expression of vascular endothelial growth factor (VEGF), vascular density (by α-SMA and CD31 staining) and myocyte cross sectional area (Gomori's reticuline staining) were assessed in ToF-1 and adult patients (referred as ToF-2, n = 12, mean age 30 years) who underwent surgery for pulmonary regurgitation and compared the data with respective age matched controls (n = 6/12). DNA microarray analysis revealed altered expression pattern for 236 genes including enhanced (1.5-2.2-fold) expression of angiogenic factors and their receptors including; VEGF, flt-1, flk-1 angiopoietin-2, FGF-2, FGF-R1, PDGF-A, whereas, flt-4, Tie, TGF-ß, TGF-ß3R showed decreased (1.6-3.4-fold) expression in ToF-patients. Northern blot analysis verified the expression patterns of VEGF and flk-1 in both ToF-1 and ToF-2 patients. VEGF staining in cardiomyocytes was increased in ToF-1 (1.5-fold, p < 0.05) as compared to ToF-2. Video image analysis revealed enhanced vascular density (p < 0.01) with enlarged myocyte cross sectional area (p < 0.01), but vascular wall thickness remained unchanged in ToF-1 patients as compared to age matched controls. Our data suggest that RVH is associated with profound changes in gene profile for a number of genes, where VEGF/VEGF-R system contributes to enhance, but stunted myocardial angiogenesis in patients with ToF.

Some phenolic compounds increase the nitric oxide level in endothelial cells in vitro.

The vasorelaxing properties of chocolate and wine might relate to the presence of phenolic compounds. One of the potential mechanisms involved is stimulation of endothelial nitric oxide (NO) production, as NO is a major regulator of vasodilatation. This study aimed to develop an in vitro assay using the hybrid human endothelial cell line EA.hy926 to rapidly screen phenolic compounds for their NO-stimulating potential. The assay was optimized, and a selection of 33 phenolics, namely, procyanidins, monomeric flavan-3-ols, flavonols, a flavone, a flavanone, a chalcone, a stilbene, and phenolic acids, was tested for their ability to enhance endothelial NO level. Resveratrol, a well-known enhancer of NO level, was included as a positive control. Of the 33 phenolics tested, only resveratrol (285% increase in NO level), quercetin (110% increase), epicatechingallate (ECg) (85% increase), and epigallocatechingallate (EGCg) (60% increase) were significant (P

Right ventricular collagen and fibronectin levels in patients with pulmonary atresia and ventricular septal defect.

Pulmonary atresia (PA) with ventricular septal defect (VSD) is an extreme form of tetralogy of Fallot with characteristic right ventricular hypertrophy. To reduce the right ventricular overload, these children have to undergo staged corrective surgery to restore physiological pulmonary perfusion. We studied the degree of fibrosis by analysing the myocardial expression pattern (at mRNA and protein level) of the extracellular matrix proteins, collagen and fibronectin in biopsies taken at corrective surgery from 14 patients affected by PA,VSD. Expression analysis by RT-PCR showed significantly higher levels for collagen III (p = 0.03), whereas collagen Ialpha (p = 0.31) and fibronectin (p = 0.47) mRNA levels remained unaltered in PA, VSD patients as compared to age matched controls. Video image analysis of immunohistochemical staining showed unchanged interstitial levels for total collagen (p = 0.17) as well as for fibronectin (p = 0.13) in the patients with PA, VSD. However, peri-vascular staining for collagen (p < 0.01) and fibronectin (p = 0.02) represented as the peri-vascular stained area corrected for the vessel lumen area showed significantly decreased levels in the PA, VSD group as compared to controls. Our results indicate that the patients with PA, VSD have inadequate extracellular matrix support for their coronary blood vessels and perhaps due to an altered biosynthesis of collagen and fibronectin network.