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Browsing by Subject "gut permeability"

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  • Toll-Like Receptor 4 activation in vitro using blood samples from a randomized clinical trial with healthy Finnish men replacing red and processed meat with legume-based foods 
    Cantini, Elisabetta (2024)
    Background. Chronic diseases are characterised by an increase of lipopolysaccharide (LPS) in the systemic circulation, a marker of gut permeability and inflammation. The intake of red and processed meat (RPM) is associated with the development of chronic diseases. In Finland, men consume about 760 g/week of RPM, which is higher than the intake recommended by the EAT-Lancet’s planetary diet (maximum 196 g/week). Studies that investigate the effects of combining plant- and animal-based protein intake on gut health and immunity are limited. The aim of this thesis is to answer whether the partial replacement of RPM intake with legume-based products would prevent the translocation of LPS from the gut to the systemic circulation of healthy Finnish men. Methods. Altogether 102 participants were recruited in Finland for the Bean man study. They were stratified and randomly divided into two dietary groups for six-weeks intervention trial: the RPM group (Meat) and the RPM and bean group (Bean). The serum was collected and used to investigate the Toll-Like Receptor 4 (TLR4) activation by LPS in Human Embryonic Kidney Cells 293 carrying TLR4, by using the QUANTI-Blue™ colorimetric assay. Statistical analysis included t-test, ANCOVA and Pearson’s correlation analysis with the p value set at 0,05. Results. There were no differences in TLR4 activation between the intervention groups (p=0,59). Red meat and processed meat intakes were weakly correlated with TLR4 activation (p= 0,08 and p= 0,013 respectively), Body Mass Index and age were not correlated with TLR4 activation (p= 0.87 and p=0.81, respectively). Conclusions. Partially replacing RPM with legume-based products did not show a significant decrease in TLR4 activation in vitro among the bean group.
  • Zebrafish as a model for endotoxin induced inflammation, gut permeability and kidney injury 
    Valle, Jenni (2018)
    Gut inflammation and permeability is speculated to play a major role in the pathophysiology of several human diseases. Signs of a low-grade gut inflammation in patients with type 1 diabetes (T1D) have been found. Focus of this study was to understand the role of gut inflammation and increased gut permeability in the development of diabetic complications, especially nephropathy. Approximately, one-third of Finnish patients with T1D develop kidney disease during their lifetime. Inflammatory mechanisms may have an essential role in the pathophysiology of the disease. Lipopolysaccharide, LPS, is found in the outer membrane of gram-negative bacteria. LPS activates innate immune system and triggers the activation of inflammatory cytokines, neutrophils and macrophages as well as many pathophysiological processes in vivo, for instance fever and endotoxic shock. Aim of this study was to establish a zebrafish gut inflammation model using fluorophore conjugated endotoxin, LPS. We hypothesized that delivery of LPS in addition to EDTA in the gut of zebrafish triggers inflammation and increased gut permeability which may lead to leakage of LPS to blood stream and potentially kidney injury. This novel zebrafish inflammation model could possibly be used for studying the pathophysiological mechanisms of gut inflammation and possible kidney injury as well as for screening new anti-inflammatory drugs. In addition, this animal model can be used for studying intestinal alkaline phosphatase (IAP) in reducing gut permeability and LPS-mediated kidney damage. IAP is an enzyme produced in small-intestinal epithelium. IAP can detoxify several bacterial endotoxins including LPS and thus protect against the induction of intestinal inflammation. LPS and EDTA were delivered in the gut of 6 days old zebrafish larvae using microgavage injection. Fluorescence microscopy imaging of live zebrafish enabled following the same individual at different timepoints after injections. Paraffin sectioning of the small larvae was promising for investigating the morphology and permeability of the gut as well as possible immunostaining for detection of IAP. L-phenylalanine was used for inhibition of IAP enzyme. Using the novel method of microinjection to gut on zebrafish larvae the timing and amount of delivered materials to gut can be controlled well. The anatomy and function of the gut in zebrafish is very similar to small intestine of mammals and the highly developed vertebrate immune system makes zebrafish an interesting model organism for studying gut inflammation and permeability. In addition, inflammatory processes can be visualized in live, intact transparent zebrafish larvae. However, the technique has a lot of challenges including small size of the fish and possible tissue damage of the fish while performing injection. More experiments need to be carried out to establish the model for drug screening. Also, along with microscopy images, a more precise way for quantification the gut permeability is needed. Based on the images it’s not yet possible to conclude whether LPS increased gut permeability or if IAP inhibition with L-phenylalanine worked in zebrafish larvae. Using adult zebrafish in the future will give more information about the chronic gut inflammation and development of possible kidney injury.

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