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Nathan Goodyear

Gut Endotoxin Leading to a Decline IN Gonadal function (GELDING) - a novel theory for t... - 0 views

  • GELDING theory (Gut Endotoxin Leading to a Decline IN Gonadal function)
  • trans-mucosal passage of bacterial lipopolysaccharide (LPS) from the gut lumen into the circulation is a key inflammatory trigger underlying male hypogonadism
  • Obesity and a high fat/high calorie diet are both reported to result in changes to gut bacteria and intestinal wall permeability, leading to the passage of bacterial endotoxin (lipopolysaccharide- LPS) from within the gut lumen into the circulation (metabolic endotoxaemia), where it initiates systemic inflammation.
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  • Endotoxin is known to reduce testosterone production by the testis, both by direct inhibition of Leydig cell steroidogenic pathways and indirectly by reducing pituitary LH drive, thereby also leading to a decline in sperm production.
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    Ever heard of the GELDING theory?  This involves the link between LPS endotoxin from the gut and low Testosterone in obese men.
Nathan Goodyear

Candida Albicans, Endotoxin, and the Intestinal Epithelial B... : Shock - 0 views

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    good discussion on the interaction and impact of Candida albicans endotoxins and the gut lining.
Nathan Goodyear

An Endotoxin-like Fraction extracted from the Cells of Candida albicans - 0 views

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    Just an abstract of a letter, however, many of the effects associated with Candida is through endotoxins.
Nathan Goodyear

The ISME Journal - An opportunistic pathogen isolated from the gut of an obese human ca... - 0 views

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    LPS endotoxin found to increase obesity rates in mice.  The bacteria balance in the gut and the toxins they produce can contribute to the incidence of obesity.
Nathan Goodyear

Loss-of-Function Mutation in Toll-Like Receptor 4 Prevents Diet-Induced Obesity and Ins... - 0 views

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    HFD and LPS endotoxin induce inflammation through TLR-4 to increase insulin resistance and obesity.
Nathan Goodyear

The Candida albicans INT1 gene facilitates cecal colonization in endotoxin-treated mice. - 0 views

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    Antibiotics lead to Candida intestinal colonization which results in increased risk of systemic candidiasis.
Nathan Goodyear

Oral spore-based probiotic supplementation was associated with reduced incidence of pos... - 0 views

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    Study finds spore probiotic for 30 days reduced LPS endotoxin by 42%, while the placebo group found a 36% increase.  As a result, and to no surprise, there was a significant drop in IL-beta.  Also, in the spore probiotic group, there was a 24% reduction in triglycerides.
Nathan Goodyear

Gut barrier function and systemic endotoxemia after laparotomy or laparoscopic resectio... - 0 views

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    Surgery increases systemic endotoxin levels via increase in intestinal permeability.
Nathan Goodyear

Metabolic endotoxemia: a molecular link between obesity and cardiovascular risk - 0 views

  • Weight gain has been associated with a higher gut permeability
  • a high-fat diet promotes LPS absorption
  • higher concentrations of fatty acids impair intestinal barrier integrity
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  • The starting point for innate immunity activation is the recognition of conserved structures of bacteria, viruses, and fungal components through pattern-recognition receptors
  • TLRs are PRRs that recognize microbe-associated molecular patterns
  • TLRs are transmembrane proteins containing extracellular domains rich in leucine repeat sequences and a cytosolic domain homologous to the IL1 receptor intracellular domain
  • The major proinflammatory mediators produced by the TLR4 activation in response to endotoxin (LPS) are TNFα, IL1β and IL6, which are also elevated in obese and insulin-resistant patients
  • Obesity, high-fat diet, diabetes, and NAFLD are associated with higher gut permeability leading to metabolic endotoxemia.
  • Probiotics, prebiotics, and antibiotic treatment can reduce LPS absorption
  • LPS promotes hepatic insulin resistance, hypertriglyceridemia, hepatic triglyceride accumulation, and secretion of pro-inflammatory cytokines promoting the progression of fatty liver disease.
  • In the endothelium, LPS induces the expression of pro-inflammatory, chemotactic, and adhesion molecules, which promotes atherosclerosis development and progression.
  • In the adipose tissue, LPS induces adipogenesis, insulin resistance, macrophage infiltration, oxidative stress, and release of pro-inflammatory cytokines and chemokines.
  • the gut microbiota has been recently proposed to be an environmental factor involved in the control of body weight and energy homeostasis by modulating plasma LPS levels
  • dietary fats alone might not be sufficient to cause overweight and obesity, suggesting that a bacterially related factor might be responsible for high-fat diet-induced obesity.
  • This was accompanied in high-fat-fed mice by a change in gut microbiota composition, with reduction in Bifidobacterium and Eubacterium spp.
  • n humans, it was also shown that meals with high-fat and high-carbohydrate content (fast-food style western diet) were able to decrease bifidobacteria levels and increase intestinal permeability and LPS concentrations
  • it was demonstrated that, more than the fat amount, its composition was a critical modulator of ME (Laugerette et al. 2012). Very recently, Mani et al. (2013) demonstrated that LPS concentration was increased by a meal rich in saturated fatty acids (SFA), while decreased after a meal rich in n-3 polyunsaturated fatty acids (n-3 PUFA).
  • this effect seems to be due to the fact that some SFA (e.g., lauric and mystiric acids) are part of the lipid-A component of LPS and also to n-3 PUFA's role on reducing LPS potency when substituting SFA in lipid-A
  • these experimental results suggest a pivotal role of CD14-mediated TLR4 activation in the development of LPS-mediated nutritional changes.
  • This suggests a link between gut microbiota, western diet, and obesity and indicates that gut microbiota manipulation can beneficially affect the host's weight and adiposity.
  • endotoxemia was independently associated with energy intake but not fat intake in a multivariate analysis
  • in vitro that endotoxemia activates pro-inflammatory cytokine/chemokine production via NFκB and MAPK signaling in preadipocytes and decreased peroxisome proliferator-activated receptor γ activity and insulin responsiveness in adipocytes.
  • T2DM patients have mean values of LPS that are 76% higher than healthy controls
  • LPS-induced release of glucagon, GH and cortisol, which inhibit glucose uptake, both peripheral and hepatic
  • LPSs also seem to induce ROS-mediated apoptosis in pancreatic cells
  • Recent evidence has been linking ME with dyslipidemia, increased intrahepatic triglycerides, development, and progression of alcoholic and nonalcoholic fatty liver disease
  • The hepatocytes, rather than hepatic macrophages, are the cells responsible for its clearance, being ultimately excreted in bile
  • All the subclasses of plasma lipoproteins can bind and neutralize the toxic effects of LPS, both in vitro (Eichbaum et al. 1991) and in vivo (Harris et al. 1990), and this phenomenon seems to be dependent on the number of phospholipids in the lipoprotein surface (Levels et al. 2001). LDL seems to be involved in LPS clearance, but this antiatherogenic effect is outweighed by its proatherogenic features
  • LPS produces hypertriglyceridemia by several mechanisms, depending on LPS concentration. In animal models, low-dose LPS increases hepatic lipoprotein (such as VLDL) synthesis, whereas high-dose LPS decreases lipoprotein catabolism
  • When a dose of LPS similar to that observed in ME was infused in humans, a 2.5-fold increase in endothelial lipase was observed, with consequent reduction in total and HDL. This mechanism may explain low HDL levels in ‘ME’ and other inflammatory conditions such as obesity and metabolic syndrome
  • It is known that the high-fat diet and the ‘ME’ increase intrahepatic triglyceride accumulation, thus synergistically contributing to the development and progression of alcoholic and NAFLD, from the initial stages characterized by intrahepatic triglyceride accumulation up to chronic inflammation (nonalcoholic steatohepatitis), fibrosis, and cirrhosis
  • On the other hand, LPS activates Kupffer cells leading to an increased production of ROS and pro-inflammatory cytokines like TNFα
  • high-fat diet mice presented with ME, which positively and significantly correlated with plasminogen activator inhibitor (PAI-1), IL1, TNFα, STAMP2, NADPHox, MCP-1, and F4/80 (a specific marker of mature macrophages) mRNAs
  • prebiotic administration reduces intestinal permeability to LPS in obese mice and is associated with decreased systemic inflammation when compared with controls
  • Cani et al. also found that high-fat diet mice presented with not only ME but also higher levels of inflammatory markers, oxidative stress, and macrophage infiltration markers
  • This suggests that important links between gut microbiota, ME, inflammation, and oxidative stress are implicated in a high-fat diet situation
  • high-fat feeding is associated with adipose tissue macrophage infiltration (F4/80-positive cells) and increased levels of chemokine MCP-1, suggesting a strong link between ME, proinflammatory status, oxidative stress, and, lately, increased CV risk
  • LPS has been shown to promote atherosclerosis
  • markers of systemic inflammation such as circulating bacterial endotoxin were elevated in patients with chronic infections and were strong predictors of increased atherosclerotic risk
  • As a TLR4 ligand, LPS has been suggested to induce atherosclerosis development and progression, via a TLR4-mediated inflammatory state.
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    Very nice updated review on Metabolic endotoxemia
Nathan Goodyear

Omega-3 Fatty Acids and Inflammatory Processes - 0 views

  • marine n-3 PUFAs have also been shown to alter the production of inflammatory proteins including chemokines, cytokines, growth factors and matrix proteases
  • Two transcription factors that are likely to play a role in inflammation are nuclear factor κ B (NFκB) and PPAR-γ
  • NFκB is the principal transcription factor involved in upregulation of inflammatory cytokine, adhesion molecule and cyclooxygenase-2 genes
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  • PPAR-γ, is believed to act in an anti-inflammatory manner
  • PPAR-γ directly regulates inflammatory gene expression, it also interferes with the activation of NFκB creating an intriguing interaction between these two transcription factors
  • Both NFκB and PPAR-γ may be regulated by n-3 PUFAs.
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    great review of the anti-inflammatory effects of omega 3 DHA and EPA.  EPA inhibits COX and 5-LOX and their downstream prostaglandin and leukotrienes.  EPA/DHA inhibited endotoxin-stimulated IL-6, IL-8,TNF-alpha, and NFkappaB.
Nathan Goodyear

Minireview: Inflammation and Obesity Pathogenesis: The Hypothalamus Heats Up - 0 views

  • Leptin, secreted by adipocytes in proportion to body fat mass
  • The saturated fatty acid palmitate (16:0) induces NF-κB signaling through a TLR4-dependent mechanism
  • 18:0 (stearic) and longer saturated fatty acids as well as linolenic acid (18:3) increased proinflammatory cytokines, ER stress markers, and TLR4 activation
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  • (SOCS)-3. A member of a protein family originally characterized as negative feedback regulators of inflammation (13, 37), SOCS3 inhibits insulin and leptin signaling
  • IKKβ signaling in discrete neuronal subsets appears to be required for both hypothalamic inflammation and excess weight gain to occur during HF feeding
  • the paradoxical observation that hyperphagia and weight gain occur when hypothalamic inflammation is induced by HF feeding, yet when it occurs in response to systemic or local inflammatory processes (e.g. administration of endotoxin), anorexia and weight loss are the rule
  • , serves as a circulating signal of energy stores in part by providing feedback inhibition of hypothalamic orexigenic pathways [e.g. neurons that express neuropeptide Y and agouti-related peptide (AgRP)]
  • and stimulating anorexigenic neurons
  • signals from Toll-like receptors (TLRs), evolutionarily conserved pattern recognition molecules critical for detecting pathogens, amplified through signaling intermediates such as MyD88 activate the inhibitor of κB-kinase-β (IKKβ)/nuclear factor-κB (NF-κB), c-Jun N-terminal kinase (Jnk) and other intracellular inflammatory signals in response to stimulation by circulating saturated fatty acids
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    great read on the current understanding of how obesity and resultant inflammation disrupts hypothalamic function.
Nathan Goodyear

Inflammation and insulin resistance 10.1016/j.febslet.2007.11.057 : FEBS Letters | Scie... - 0 views

  • A subsequent study by Yuan et al. showed that Tnf treatment of 3T3L1 adipocytes induces insulin resistance and that this could be prevented by pretreatment of cells with aspirin
  • Activation of the Tnf receptor results in stimulation of NFκB signaling via Ikkb
  • Insulin is a pleiotropic hormone
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  • the percentage of macrophages in a given adipose tissue depot is positively correlated with adiposity and adipocyte size
  • Il-10 is an anti-inflammatory cytokine produced by macrophages and lymphocytes
  • Il-10 exerts its anti-inflammatory activity by inhibiting Tnf-induced NFκB activation by reducing IKK activity [38]
  • adipose tissue macrophages are responsible for nearly all adipose tissue Tnf expression and a significant portion of Nos2 and Il6 expression
  • One theory holds that the expansion of adipose tissue leads to adipocyte hypertrophy and hyperplasia and that large adipocytes outstrip the local oxygen supply leading to cell autonomous hypoxia with activation of cellular stress pathways
  • The use of the anti-inflammatory compounds, salicylate and its derivative aspirin, for treating symptoms of T2DM dates back over 100 years
  • elevated levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin (IL-8) have all been reported in various diabetic and insulin resistant states
  • overnutrition and obesity are often accompanied by elevations in tissue and circulating FFA concentrations, and saturated FFAs can directly activate pro-inflammatory responses
  • Adipokines such as resistin, leptin and adiponectin, which are secreted by adipocytes, can also affect inflammation and insulin sensitivity
  • In skeletal muscle insulin promotes glucose uptake by stimulating translocation of the GLUT4 glucose transporter
  • macrophages are also capable of undergoing a phenotypic switch from an M1 state, which was defined as the “classically activated” pro-inflammatory macrophage, to the M2 state or the “alternatively activated” non-inflammatory cell
  • saturated fatty acids are the most potent inducers of this inflammatory response
  • Several inducers of insulin resistance, including FFAs, pro-inflammatory cytokines and oxidative stress, activate the expression of Nos2, the gene that encodes iNOS (reviewed in [33]
  • Adipose tissue insulin signaling results in decreased hormone sensitive lipase activity and this anti-lipolytic effect inhibits free fatty acid (FFA) efflux out of adipocytes.
  • In the liver, insulin inhibits the expression of key gluconeogenic enzymes and, therefore, insulin resistance in liver leads to elevated hepatic glucose production
  • elevated JNK activity in liver, adipose tissue and skeletal muscle of obese insulin resistant mice, and knockout of Jnk1 (Jnk1−/−) leads to amelioration of insulin resistance in high fat diet
  • Adipose tissue from obese mice contains proportionately more M1 macrophages, whereas, lean adipose tissue contains more M2 macrophages, and increased M1 content positively correlates with inflammation, macrophage infiltration and insulin resistance
  • C-reactive protein (CRP)
  • these studies highlight the possibility that increased iNOS activity plays a direct role in the pathogenesis of insulin resistance
  • the important role of Ikkb in the development of obesity and inflammation-induced insulin resistance.
  • It is probable that local concentrations of inflammatory mediators, such as FFAs, Tnf or other cytokines/adipokines contribute to this polarity switch
  • Tnf and other cytokines/chemokines are symptomatic of inflammation, and while they propagate and/or maintain the inflammatory state, they are not the initial cause(s) of inflammation
  • Tlr4, in particular, is stimulated by lipopolysaccharide (LPS), an endotoxin released by gram-negative bacteria
  • Tlr4 belongs to the family of Toll-like receptors that function as pattern recognition receptors that guard against microorganismal infections as part of the innate immune system.
  • Tlr4 stimulation results in the activation of both Ikkb/NFκB and JNK/AP-1 signaling, culminating in the expression and secretion of pro-inflammatory cytokines/chemokines, including, Il1b, IL-6, Tnf, Mcp1, etc. (reviewed in [57
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    Great review of all the known components in the inflammation, insulin resistance link
Nathan Goodyear

Bacterial Endotoxin Activity in Human Serum Is Associated With Dyslipidemia, Insulin Re... - 0 views

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    LPS linked to dsylipidemia, insulin resistance, obesity, and chronic inflammation.
Nathan Goodyear

Mortality of Candida albicans-infected mice is ... [J Infect Dis. 1995] - PubMed - NCBI - 0 views

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    LPS from gram negative E. coli worsens negative effects of Candida albicans on mice cells.
Nathan Goodyear

Diet-Induced Dysbiosis of the Intestinal Microbiota and the Effects on Immunity and Dis... - 0 views

  • The gut microbiota participates in the body’s metabolism by affecting energy balance, glucose metabolism, and low-grade inflammation associated with obesity and related metabolic disorders
  • Firmicutes and Bacteroidetes represent the two largest phyla in the human and mouse microbiota and a shift in the ratio of these phyla has been associated with many disease conditions, including obesity
  • In obese humans, there is decreased abundance of Bacteroidetes compared to lean individuals
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  • weight loss in obese individuals results in an increase in the abundance of Bacteroidetes
  • there is conflicting evidence on the composition of the obese microbiota phenotype with regards to Bacteroidetes and Firmicutes ratios
  • Bifidobacteria spp. from the phyla Actinobacteria, has been shown to be depleted in both obese mice and human subjects
  • While it is not yet clear which specific microbes are inducing or preventing obesity, evidence suggests that the microbiota is a factor.
  • targeted manipulation of the microbiota results in divergent metabolic outcomes depending on the composition of the diet
  • The microbiota has been linked to insulin resistance or type 2 diabetes (T2D) via metabolic syndrome and indeed the microbiota of individuals with T2D is also characterized by an increased Bacteroidetes/Firmicutes ratio, as well as an increase in Bacillus and Lactobacillus spp
  • It was also observed that the ratio of Bacteriodes-Prevotella to C. coccoides-E. rectale positively correlated with glucose levels but did not correlate with body mass index [80]. This suggests that the microbiota may influence T2D in conjunction with or independently of obesity
  • In humans, high-fat Western-style diets fed to individuals over one month can induce a 71% increase in plasma levels of endotoxins, suggesting that endotoxemia may develop in individuals with GI barrier dyfunction connected to dysbiosis
  • LPS increases macrophage infiltration essential for systemic inflammation preceding insulin resistance, LPS alone does not impair glucose metabolism
  • early treatment of dysbiosis may slow down or prevent the epidemic of metabolic diseases and hence the corresponding lethal cardiovascular consequences
  • increased Firmicutes and decreased Bacteroidetes, which is the microbial profile found in lean phenotypes, along with an increase in Bifidobacteria spp. and Lactobacillus spp
  • mouse and rat models of T1D have been shown to have microbiota marked by decreased diversity and decreased Lactobacillus spp., as well as a decrease in the Firmicutes/Bacteroidetes ratio
  • microbial antigens through the innate immune system are involved in T1D progression
  • The microbiota appears to be essential in maintaining the Th17/Treg cell balance in intestinal tissues, mesenteric and pancreatic lymph nodes, and in developing insulitis, although progression to overt diabetes has not been shown to be controlled by the microbiota
  • There is evidence that dietary and microbial antigens independently influence T1D
  • Lactobacillus johnsonii N6.2 protects BB-rats from T1D by mediating intestinal barrier function and inflammation [101,102] and a combination probiotic VSL#3 has been shown to attenuate insulitis and diabetes in NOD mice
  • breast fed infants have higher levels of Bifidobacteria spp. while formula fed infants have higher levels of Bacteroides spp., as well as increased Clostridium coccoides and Lactobacillus spp
  • the composition of the gut microbiota strongly correlates with diet
  • In mice fed a diet high in fat, there are many key gut population changes, such as the absence of gut barrier-protecting Bifidobacteria spp
  • diet has a dominating role in shaping gut microbiota and changing key populations may transform healthy gut microbiota into a disease-inducing entity
  • “Western” diet, which is high in sugar and fat, causes dysbiosis which affects both host GI tract metabolism and immune homeostasis
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    Nice discussion of how diet, induces gut bacterial change, that leads to metabolic endotoxemia and disease.
Nathan Goodyear

Frontiers | Microbiome-Derived Lipopolysaccharide Enriched in the Perinuclear Region of... - 0 views

  • lipopolysaccharides (LPS), either alone or in combination, have indicated that when compared, bacterial LPSs exhibit the strongest induction of pro-inflammatory signaling in human neuronal–glial cells in primary coculture of any single inducer, and different LPS extracts from different gastrointestinal (GI)-tract resident Gram-negative bacteria appeared to have different pro-inflammatory potential
  • powerful inducer of the NF-κB
  • In both neocortex and hippocampus, LPS has been detected to range from a ~7- to ~21-fold increase abundance in AD brain
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  • Major Gram-negative bacilli of the human GI-tract, such as the abundant B. fragilis and Escherichia coli (E. coli), are capable of discharging a remarkably complex assortment of pro-inflammatory neurotoxins
  • (i) bacterial amyloids (10, 21); (ii) endotoxins and exotoxins (5, 12); (iii) LPS (12, 18); and (iv) small non-coding RNAs (sncRNAs)
  • integral components of the outer leaflet of the outer membrane of Gram-negative bacteria, LPS
  • LPS, the major molecular component of the outer membrane of Gram-negative bacteria normally serves as a physical barrier providing the bacteria protection from its surroundings
  • LPS is also recognized by the immune system as a marker for the detection of bacterial pathogen invasion and responsible for the development of inflammatory response is perhaps the most potent stimulator and trigger of inflammation known
  • AD-affected brains have remarkably large loads of bacterial-derived toxins compared to controls. The transfer of noxious, pro-inflammatory molecules from the GI-tract microbiome to the CNS may be increasingly important during the course of aging when both the GI-tract and blood–brain barriers become significantly more permeable
  • first evidence of a perinuclear association of LPS with AD brain cell nuclei
  • LPS-mediated stimulation of chronic inflammation, beta-amyloid accumulation, and episodic memory decline in murine models of AD (39, 40) and a biophysical association of LPS with amyloid deposits and blood vessels in human AD patients
  • Strong adherence of LPS to the nuclear periphery has recently been shown to inhibit nuclear maturation and function that may impair or block export of mRNA signals from brain cell nuclei, a highly active organelle with extremely high rates of transcription, mRNA processing, and export into the cytoplasm
  • LPS may be further injurious to the nuclear membrane just as LPS contributes to cerebrovascular endothelial cell membrane injury
  • high intake of dietary fiber is a strong inhibitor of B. fragilis abundance and proliferation in the intact human GI-tract and as such is a potent inhibitor of the neurotoxic B. fragilis-derived amyloids, LPS, enterotoxins, and sncRNAs.
  • GI-tract microbiome-derived LPS may be an important initiator and/or significant contributor to inflammatory degeneration in the AD CNS
  • LPS has been recently localized to the same anatomical regions involved in AD-type neuropathology
  • a known pro-inflammatory transcription factor complex that triggers the expression of pathogenic pathways involved in neurodegenerative inflammation
  • pro-inflammatory amyloids, endo- and exotoxins, LPSs, and sncRNAs but also serve as potent sources of membrane-disrupting agents
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    LPS links gut to inflammation in Alzheimer's disease
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