High Lipopolysaccharide Levels Research Articles

Long-Term Exposure to Polystyrene Microspheres and High-Fat Diet-Induced Obesity in Mice: Evaluating a Role for Microbiota Dysbiosis.

Microplastics (MPs) have become a global environmental problem, emerging as contaminants with potentially alarming consequences. However, long-term exposure to polystyrene microspheres (PS-MS) and its effects on diet-induced obesity are not yet fully understood. We aimed to investigate the effect of PS-MS exposure on high-fat diet (HFD)-induced obesity and underlying mechanisms. In the present study, C57BL/6J mice were fed a normal diet (ND) or a HFD in the absence or presence of PS-MS via oral administration for 8 wk. Antibiotic depletion of the microbiota and fecal microbiota transplantation (FMT) were performed to assess the influence of PS-MS on intestinal microbial ecology. We performed 16S rRNA sequencing to dissect microbial discrepancies and investigated the dysbiosis-associated intestinal integrity and inflammation in serum. Compared with HFD mice, mice fed the HFD with PS-MS exhibited higher body weight, liver weight, metabolic dysfunction-associated steatotic liver disease (MASLD) activity scores, and mass of white adipose tissue, as well as higher blood glucose and serum lipid concentrations. Furthermore, 16S rRNA sequencing of the fecal microbiota revealed that mice fed the HFD with PS-MS had greater -diversity and greater relative abundances of Lachnospiraceae, Oscillospiraceae, Bacteroidaceae, Akkermansiaceae, Marinifilaceae, Deferribacteres, and Desulfovibrio, but lower relative abundances of Atopobiaceae, Bifidobacterium, and Parabacteroides. Mice fed the HFD with PS-MS exhibited lower expression of MUC2 mucin and higher levels of lipopolysaccharide and inflammatory cytokines [tumor necrosis factor- (TNF-), interleukin-6 (IL-6), IL-1, and IL-17A] in serum. Correlation analyses revealed that differences in the microbial flora of mice exposed to PS-MS were associated with obesity. Interestingly, microbiota-depleted mice did not show the same PS-MS-associated differences in Muc2 and Tjp1 expression in the distal colon, expression of inflammatory cytokines in serum, or obesity outcomes between HFD and HFD + PS-MS. Importantly, transplantation of feces from HFD + PS-MS mice to microbiota-depleted HFD-fed mice resulted in a lower expression of mucus proteins, higher expression of inflammatory cytokines, and obesity outcomes, similar to the findings in HFD + PS-MS mice. Our findings provide a new gut microbiota-driven mechanism for PS-MS-induced obesity in HFD-fed mice, suggesting the need to reevaluate the adverse health effects of MPs commonly found in daily life, particularly in susceptible populations. https://doi.org/10.1289/EHP13913.

Effect of the bacterial lipopolysaccharide (LPS) on vitamin B1 (thiamin) uptake along the intestinal tract: inhibition mediated via reduction in level of expression of thiamin transporter-1 & -2 proteins at the cell membrane

Background: LPS is a potent bacterial virulence factor and is a source of considerable clinical morbidity and mortality. This endotoxin is a predominant component of the outer membrane of Gram-negative bacteria. The gut is exposed to high levels of LPS in conditions like Inflammatory Bowel Diseases, necrotizing enterocolitis, sepsis, and following infection with enteric pathogens. Studies have shown that exposure of gut epithelial/other cells to LPS exerts profound and differential effects on membrane transport processes. Nothing, however, is known about the effect of LPS on uptake of free thiamin in the small intestine (where absorption of dietary thiamin occurs), and the large intestine (where absorption of the microbiota-generated thiamin occurs). Aim: To examine the effect of LPS on the small and large intestinal uptake of free thiamin and to determine the mechanism(s) involved. Methods: We used in vitro (human duodenum-derived HuTu 80 cells and colon-derived non-transformed NCM460 cells), ex vivo (human differentiated polarized enteroid and colonoid monolayers), and in vivo (mouse) models in our studies. Uptake studies were performed using 3H-thiamin as substrate. Results: Treating intestinal HuTu 80 and colonic NCM460 epithelial cells with LPS led to a significant inhibition in carrier-mediated 3H-thiamin uptake. Similar results were obtained when human differentiated enteroid and colonoid monolayers ex vivo, and mouse in vivo were treated with LPS. No changes in total cellular levels of thiamin transporter-1 & -2 (THTR-1 and THTR-2, respectively) proteins and mRNAs were observed upon LPS treatments; however, a significant decrease in the fraction of the THTR-1 & THTR-2 proteins that are expressed at the cell membrane were observed. These findings suggest that the LPS inhibitory effect on thiamin uptake in the small and large intestine is likely mediated via a decrease in the fraction of the thiamin transporters that are expressed at the cell membrane. Conclusion: This study shows that bacterial LPS inhibits thiamin uptake along the intestinal tract, and that this inhibition is likely mediated via reduction in level of the THTR-1 & THTR-2 proteins at the cell membrane. Supported by NIH grants DK-56061 and AA-018071, and VA grants 101BX001142 & IK6BX006189. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Abstract 2441: Higher levels of LPS in blood plasma as potential novel biomarker for cancer risk in Puerto Rican people living with HIV

Abstract Background: People living with HIV (PWH) have a significantly higher risk of developing cancers than people without HIV (PWOH), even with suppressive antiretroviral therapy. Puerto Rico (PR) is considered a high-risk group disproportionately affected by HIV and a priority group for cancer prevention strategies. Dysbiosis of the human microbiota can contribute to persistent inflammation by upregulating TGF-β (microbial-induced oncogenesis biomarker), which can promote the translocation of microbial products into the bloodstream, increasing cancer risk at local and distant sites. However, the relationship between TGF-β, and microbial products such as lipopolysaccharide (LPS) and short-chain fatty acids (SCFA) in relation to HIV infection is poorly understood, therefore we aimed to quantify the levels of LPS and SCFA in the blood plasma of PWH vs. PWOH and investigated their relationship with cancer risk measured by TGF-β. Methods: Blood samples, sociodemographic, and clinical data from 80 adults (50 PWH and 30 PWOH) were collected. PWH were virally suppressed (<50 copies/mL) with a median CD4 count of 699.8 cells/µL. We measured TGF-β, LPS, and soluble CD14 (sCD14. marker of innate immune activation and microbial translocation) using immunoassays. SCFA (acetate, butyrate, and propionate) were measured using gas chromatography followed by mass spectrometry. Differences in the median levels of TGF-β, LPS, and SCFAs were evaluated using a Mann-Whitney test. We assessed the effects of LPS, SCFAs, and HIV infections in relationship with levels of TGF-β using multivariate fixed-effects regression analysis in R-statistical software. Results: PWH had significantly higher levels of TGF-β (4397 pg/mL vs. 1121 pg/mL, p=0.017), higher levels of LPS (38.97 pg/mL vs. 19.26 pg/mL, p<0.001), higher levels of sCD14 (1326 pg/mL vs. 1137 pg/mL, p=0.007), and significantly lower levels of butyrate (84.5 ng/mL vs. 62.0 ng/mL, p<0.001). Higher levels of TGF-b were associated with higher levels of LPS (rho=0.38, p=0.017) and higher levels of sCD14 (rho=0.27, p=0.016) these relationships remain significant after adjusting for HIV status (p<0.001). Conclusion: Our findings suggest that microbial products in blood plasma can contribute to higher cancer risk in Puerto Rican PWH and may represent potential novel biomarkers for cancer prevention. Citation Format: Jurelis Torres Reyes, Tanner L. Shull, Gabriel Borges-Velez, Veronica S. Sanchez Gonzalez, Jeannette L. Salgado Montilla, Josue Perez Santiago. Higher levels of LPS in blood plasma as potential novel biomarker for cancer risk in Puerto Rican people living with HIV [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2441.

Mesenteric adipose tissue B lymphocytes promote intestinal injury in severe acute pancreatitis by mediating enteric pyroptosis

BackgroundVisceral adipose tissue (VAT) has been linked to the severe acute pancreatitis (SAP) prognosis, although the underlying mechanism remains unclear. It has been reported that pyroptosis worsens SAP. The present study aimed to verify whether mesenteric adipose tissue (MAT, a component of VAT) can cause secondary intestinal injury through the pyroptotic pathway. MethodsThirty-six male Sprague Dawley (SD) rats were divided into six different groups. Twelve rats were randomly divided into the SAP and control groups. We monitored the changes of MAT and B lymphocytes infiltration in MAT of SAP rats. Twelve SAP rats were injected with MAT B lymphocytes or phosphate buffer solution (PBS). The remaining twelve SAP rats were first injected with MAT B lymphocytes, and then with MCC950 (NLRP3 inhibitor) or PBS. We collected blood and tissue samples from pancreas, gut and MAT for analysis. ResultsCompared to the control rats, the SAP group showed inflammation in MAT, including higher expression of tumor necrosis factor (TNF-α) and interleukin-6 (IL-6), lower expression of IL-10, and histological changes. Flow cytometry analysis revealed B lymphocytes infiltration in MAT but not T lymphocytes and macrophages. The SAP rats also exhibited intestinal injury, characterized by lower expression of zonula occludens-1 (ZO-1) and occludin, higher levels of lipopolysaccharide and diamine oxidase, and pathological changes. The expression of NLRP3 and n-GSDMD, which are responsible for pyroptosis, was increased in the intestine of SAP rats. The injection of MAT B lymphocytes into SAP rats exacerbated the inflammation in MAT. The upregulation of pyroptosis reduced tight junction in the intestine, which contributed to the SAP progression, including higher inflammatory indicators and worse histological changes. The administration of MCC950 to SAP + MAT B rats downregulated pyroptosis, which subsequently improved the intestinal barrier and ameliorated inflammatory response of SAP. ConclusionsIn SAP, MAT B lymphocytes aggravated local inflammation, and promoted the injury to the intestine through the enteric pyroptotic pathway.

Low-grade endotoxemia, oxidative stress and thrombotic events in patients with primary antiphospholipid syndrome

Abstract Introduction The persistence of antiphospholipid antibodies (aPL) is associated with a procoagulant state that could precipitate thrombotic events in the presence of a second pro-inflammatory stimulus, realizing thus the antiphosholipid syndrome (APS). Circulating lipopolysaccharide (LPS) is associated with systemic inflammation, enhanced oxidative stress and cardiovascular events in different clinical conditions, however, its presence and significance has not been evaluated in APS. Purpose To investigate the relationship between LPS, oxidative stress markers and risk of thrombotic events in the prospective multicenter ATHERO-APS study. Methods Baseline serum levels comparison of LPS, soluble NADPH oxidase 2-derived peptide (sNOX-dp), H2O2 production, hydrogen peroxide breakdown activity (HBA), and nitric oxide (NO) bioavailability in 97 primary APS (PAPS), 20 aPL carriers and 20 healthy controls (CTRL) matched for age, sex and BMI. In patients with high LPS levels, Cox-regression analysis was performed to assess the risk for a composite outcome of cardiovascular death, venous (VTE) and arterial thromboembolism (ATE). Results In the whole population (median age 51 (IQR: 45-61) years, 72% female), LPS levels were inversely correlated with HBA (Rs: -0.231, p=0.009) and NO (rS: -0.286, p=0.001) and directly correlated with sNOX-dp (rS:0.423, p<0.001) and H202 (rS: 0.211, p=0.017) (Table 1). Patients with PAPS showed a significant increased levels of LPS, sNOX-dp and H2O2 and a significant lower level of NO and HBA compared to aPL carriers and healthy CTRL. No correlation was found between LPS levels and anti-cardiolipin (aCL) IgG/IgM, anti-beta-2-Glycoprotein-I (aβ2GPI) IgG/IgM and lupus anticoagulant (LAC). After a median follow-up of 4.7 (4.1-5.6) years, 11 composite outcomes were reported: 1 cardiovascular death (stroke related), 3 ischemic strokes, 2 myocardial infarctions, 3 peripheral ATE and 2 VTE. Patients with basal LPS levels above the median value (>20.1 pg/ml) showed a higher annual incidence of composite outcome compared to those with LPS levels below the median value (4.0% vs 0.7%, p=0.013). On Cox-regression analysis, PAPS patients with LPS above the median value showed a 5-fold increased risk of composite outcome compared to patients with LPS below the median value, after adjustment for age, sex, aCL IgG, aβ2GPI IgG and LAC (Figure 1). Conclusion These preliminary data suggest that in PAPS, LPS is associated with a higher risk for a composite outcome of cardiovascular death, ATE and VTE. Further studies are needed to know which pharmacological approach may counteract the prothrombotic effect of LPS.

Estrogen deficiency induces bone loss through the gut microbiota

Postmenopausal osteoporosis is a common bone metabolic disease, and gut microbiota (GM) imbalance plays an important role in the development of metabolic bone disease. Here, we show that ovariectomized mice had high levels of lipopolysaccharide in serum and gut microbiota dysbiosis through increases in luminal Firmicutes:Bacteroidetes ratio. We depleted the GM through antibiotic treatment and observed improvements in bone mass, bone microstructure, and bone strength in ovariectomized mice. Conversely, transplantation of GM adapted to ovariectomy induced bone loss. However, GM depletion reversed ovariectomy-induced gene expression in the tibia and increased periosteal bone formation. Furthermore, bioinformatics analysis revealed that the G-protein-coupled bile acid receptor (TGR5) and systemic inflammatory factors play key roles in bone metabolism. Silencing TGR5 expression through small interfering RNA (siRNA) in the local tibia and knockout of TGR5 attenuated the effects of GM depletion in ovariectomized mice, confirming these findings. Thus, this study highlights the critical role of the GM in inducing bone loss in ovariectomized mice and suggests that targeting TGR5 within the GM may have therapeutic potential for postmenopausal osteoporosis.

Phytosphingosine alleviates Staphylococcus aureus-induced mastitis by inhibiting inflammatory responses and improving the blood-milk barrier in mice

Mastitis is one of the common diseases in dairy cows which threatens the health of cows and impacts on economic benefits seriously. Recent studies have been showed that Subacute Ruminal Acidosis (SARA) increased the susceptibility of cow mastitis. SARA leads the disturbance of the rumen microbiota, and the rumen bacterial disordered community is an important endogenous factor of cow mastitis. That is to say, cows which suffer from SARA have a disordered rumen microbiota, a prolonged decline in ruminal PH and a high level of lipopolysaccharide (LPS) in the rumen, blood. Therefore, ruminal metabolism is closely related to the rumen microbiota. However, the specific mechanism of SARA and mastitis still not clear. We found an intestinal metabolite according to the metabonomics, which is correlated to inflammation. Phytophingosine (PS), a product from rumen fluid and milk of the cows which suffer from SARA and mastitis. It has the effect of killing bacteria and anti-inflammatory. Emerging evidences indicate that PS can alleviate inflammatory diseases. However, how PS affects mastitis is largely unknown. In this study, we explored the concrete role of PS on Staphylococcus aureus (S. aureus) -induced mastitis in mice. We found that PS obviously decreased the level of the proinflammatory cytokines. Meanwhile, PS also significantly relieved the mammary gland inflammation caused by S. aureus and restored the function of the blood-milk barrier. Here, we showed that PS increased the expression of the classic Tight-junctions (TJs) proteins including ZO-1, Occludin and Claudin-3. Moreover, PS improves S. aureus-induced mastitis by inhibiting the activation of the NF-κB and NLRP3 signaling pathways. These data indicated that PS relieved S. aureus-induced mastitis effectively. This also provides a reference for exploring the correlation between the intestinal metabolism and inflammation.

Microbial lipopolysaccharide-induced inflammation contributes to cognitive impairment and white matter lesion progression in diet-induced obese mice with chronic cerebral hypoperfusion.

White matter lesions (WMLs) are involved in the pathological processes leading to cognitive decline and dementia. We examined the mechanisms underlying the exacerbation of ischemia-induced cognitive impairment and WMLs by diet-induced obesity, including lipopolysaccharide (LPS)-triggered neuroinflammation via toll-like receptor (TLR) 4. Wild-type (WT) and TLR4-knockout (KO) C57BL/6 mice were fed a high-fat diet (HFD) or low-fat diet (LFD), and subjected to bilateral carotid artery stenosis (BCAS). Diet groups were compared for changes in gut microbiota, intestinal permeability, systemic inflammation, neuroinflammation, WML severity, and cognitive dysfunction. In WT mice, HFD induced obesity and increased cognitive impairment and WML severity compared with LFD-fed mice following BCAS. HFD caused gut dysbiosis and increased intestinal permeability, and plasma LPS and pro-inflammatory cytokine concentrations. Furthermore, HFD-fed mice had higher LPS levels and higher neuroinflammatory status, including increased TLR4 expression, in WMLs. In TLR4-KO mice, HFD also caused obesity and gut dysbiosis but did not increase cognitive impairment or WML severity after BCAS. No difference was found between HFD- and LFD-fed KO mice for LPS levels or inflammatory status in either plasma or WMLs. Inflammation triggered by LPS-TLR4 signaling may mediate obesity-associated exacerbation of cognitive impairment and WMLs from brain ischemia.

Amelioration of autophagy and inflammatory signaling pathways via α-lipoic acid, burdock and bee pollen versus lipopolysaccharide-induced insulin resistance in murine model

Lipopolysaccharide (LPS) has previously been implicated in insulin resistance by generating an innate immune response and activating inflammatory cascades. Many studies have discovered a relationship between high levels of serum LPS and the advancement of diabetic microvascular problems, indicating that LPS may play a role in the control of critical signaling pathways connected to insulin resistance. The current study focused on signaling pathways linked to insulin resistance and explored probable mechanisms of LPS-induced insulin resistance in a murine model. It next looked at the effects of burdock, bee pollen, and -lipoic acid on LPS-induced inflammation and autoimmune defects in rats. LPS intoxication was induced via ip injection for one week in a dose of 10 mg/kg followed by α-lipoic acid, Burdock and bee pollen in an oral treatment for one month. Following that, biochemical and molecular studies were performed. The RNA expression of the regulating genes STAT5A and PTEN was measured. In addition, ATF-4 and CHOP as autophagy biomarkers were also subjected to mRNA quantification. The results demonstrated a considerable improvement in the -lipoic acid, Burdock, and bee pollen treated groups via modifying oxidative stress indicators as well as molecular ones. Furthermore, glucose concentration in serum and α-amylase were also improved upon treatment with the superiority of α-lipoic acid for modulating all estimated parameters. In conclusion: the results declared in the current study suggested that α-lipoic acid could regulate insulin resistance signaling pathways induced by LPS intoxication.

Endotoxin tolerance and low activation of TLR-4/NF-κB axis in monocytes of COVID-19 patients.

Higher endotoxin in the circulation may indicate a compromised state of host immune response against coinfections in severe COVID-19 patients. We evaluated the inflammatory response of monocytes from COVID-19 patients after lipopolysaccharide (LPS) challenge. Whole blood samples of healthy controls, patients with mild COVID-19, and patients with severe COVID-19 were incubated with LPS for 2h. Severe COVID-19 patients presented higher LPS and sCD14 levels in the plasma than healthy controls and mild COVID-19 patients. In non-stimulated in vitro condition, severe COVID-19 patients presented higher inflammatory cytokines and PGE-2 levels and CD14 + HLA-DRlow monocytes frequency than controls. Moreover, severe COVID-19 patients presented higher NF-κB p65 phosphorylation in CD14 + HLA-DRlow, as well as higher expression of TLR-4 and NF-κB p65 phosphorylation in CD14 + HLA-DRhigh compared to controls. The stimulation of LPS in whole blood of severe COVID-19 patients leads to lower cytokine production but higher PGE-2 levels compared to controls. Endotoxin challenge with both concentrations reduced the frequency of CD14 + HLA-DRlow in severe COVID-19 patients, but the increases in TLR-4 expression and NF-κB p65 phosphorylation were more pronounced in both CD14 + monocytes of healthy controls and mild COVID-19 patients compared to severe COVID-19 group. We conclude that acute SARS-CoV-2 infection is associated with diminished endotoxin response in monocytes. KEY MESSAGES: Severe COVID-19 patients had higher levels of LPS and systemic IL-6 and TNF-α. Severe COVID-19 patients presented higher CD14+HLA-DRlow monocytes. Increased TLR-4/NF-κB axis was identified in monocytes of severe COVID-19. Blunted production of cytokines after whole blood LPS stimulation in severe COVID-19. Lower TLR-4/NF-κB activation in monocytes after LPS stimulation in severe COVID-19.

Crosstalk between imbalanced gut microbiota caused by antibiotic exposure and rotavirus replication in the intestine

ObjectiveRotavirus (RV), one of non-enveloped double-strained RNA viruses, can cause infantile diarrheal illness. It is widely accepted that RV is transmitted mainly via feces-oral route. However, infected asymptomatic adults are becoming the source of infection. It is necessary to explore the underlying mechanism of RV replication in adult's intestine. MethodsAfter recruiting healthy volunteers and RV asymptomatic carriers, we firstly investigated the association of animal-derived food intake with antibiotic level in urine samples. Secondly, we compared the difference in the structure of gut microbiota, and identified the taxa that most likely explained the difference. Finally, we investigated the impact of lipopolysaccharide (LPS), produced by gram-negative bacteria, on RV replication in vivo and in vitro. ResultsWe found that 10% of participants were RV asymptomatic carriers in our study. High intake of animal-derived food was positively correlated to antibiotic level in urine samples. The disrupted gut microbiota in RV carriers was characterized by high abundance of antibiotic resistant gram-negative bacteria and high level of LPS. The disrupted gut microbiota caused by penicillin treatment was benefit to RV replication in vivo. LPS enhanced RV thermal stability in vitro. ConclusionsOur findings suggest that the imbalanced gut microbiota caused by antibiotic exposure plays an important role in RV replication, and brings risk to health complications.

Low-grade endotoxemia and NOX2 in patients with coronary microvascular angina.

Endothelial dysfunction and oxidative stress were hypothesized to be involved in the pathogenesis of coronary microvascular angina (MVA). NADPH oxidase-2 (NOX2) activation could provoke increased oxidative stress and endothelial dysfunction, but data on MVA have not been provided yet. This study aimed to evaluate the interaction among NOX2 activation, serum lipopolysaccharide (LPS) levels, as well as oxidative stress production as potential causes of endothelial dysfunction in MVA patients. In this study, we wanted to compare serum levels of soluble NOX2-dp (sNOX2-dp), H2O2 production, hydrogen peroxide breakdown activity (HBA), nitric oxide (NO) bioavailability, endothelin 1 (ET-1), serum zonulin (as intestinal permeability assay), and LPS in 80 consecutive subjects, including 40 MVA patients and 40 controls (CT), matched for age and sex. Compared with CT, MVA patients had significantly higher values of sNOX2-dp, H2O2, ET-1, LPS, and zonulin. Conversely HBA and NO bioavailability were significantly lower in MVA patients. Simple linear regression analysis showed that sNOX2 was associated with serum LPS, serum zonulin, H2O2, and ET-1. Furthermore, an inverse correlation between sNOX2, HBA, and nitric oxide bioavailability was observed. Multiple linear regression analysis showed that LPS and zonulin emerged as the only independent predictive variables associated with sNOX2. This study provides the first report attesting that patients with MVA have high LPS levels, NOX2 activation, and an imbalance between pro-oxidant and antioxidant systems, in favor of the oxidizing molecules that could be potentially implicated in the endothelial dysfunction and vasoconstriction of this disease.

ASSOCIATION OF PLASMA MICROBIAL COMPOSITION WITH A LEAKY GUT IN OBESITY-RELATED OA

Purpose: Higher levels of lipopolysaccharide (LPS) have been found in plasma and synovial fluid from individuals with knee OA, and microbial DNA has been detected in OA cartilage (PMID: 27216281). This suggests increased intestinal permeability (or a

Phenotypic and Functional Responses of Human Decidua Basalis Mesenchymal Stem/Stromal Cells to Lipopolysaccharide of Gram-Negative Bacteria.

IntroductionHuman decidua basalis mesenchymal stem cells (DBMSCs) are potential therapeutics for the medication to cure inflammatory diseases, like atherosclerosis. The current study investigates the capacity of DBMSCs to stay alive and function in a harmful inflammatory environment induced by high levels of lipopolysaccharide (LPS).MethodsDBMSCs were exposed to different levels of LPS, and their viability and functional responses (proliferation, adhesion, and migration) were examined. Furthermore, DBMSCs’ expression of 84 genes associated with their functional activities in the presence of LPS was investigated.ResultsResults indicated that LPS had no significant effect on DBMSCs’ adhesion, migration, and proliferation (24 h and 72 h) (p > 0.05). However, DBMSCs’ proliferation was significantly reduced at 10 µg/mL of LPS at 48 h (p < 0.05). In addition, inflammatory cytokines and receptors related to adhesion, proliferation, migration, and differentiation were significantly overexpressed when DBMSCs were treated with 10 µg/mL of LPS (p < 0.05).ConclusionThese results indicated that DBMSCs maintained their functional activities (proliferation, adhesion, and migration) in the presence of LPS as there was no variation between the treated DBMSCs and the control group. This study will lay the foundation for future preclinical and clinical studies to confirm the appropriateness of DBMSCs as a potential medication to cure inflammatory diseases, like atherosclerosis.

The Role of β-Carotene in Colonic Inflammation and Intestinal Barrier Integrity.

Background: Carotenoids are naturally occurring pigments accounting for the brilliant colors of fruits and vegetables. They may display antioxidant and anti-inflammatory properties in humans besides being precursors to vitamin A. There is a gap of knowledge in examining their role within colonic epithelial cells. We proposed to address this research gap by examining the effects of a major dietary carotenoid, β-carotene, in the in vitro epithelial cell model.Methods: We examined the function of β-carotene in the lipopolysaccharide (LPS)/toll-like receptor 4 (TLR4) signaling pathway. We conducted western blotting assays to evaluate expressions of TLR4 and its co-receptor, CD14. We also examined NF-κB p65 subunit protein levels in the model system. Furthermore, we studied the impact of β-carotene on the tight junction proteins, claudin-1, and occludin. We further carried out immunocytochemistry experiments to detect and visualize claudin-1 expression.Results: β-Carotene reduced LPS-induced intestinal inflammation in colonic epithelial cells. β-Carotene also promoted the levels of tight junction proteins, which might lead to enhanced barrier function.Conclusions: β-Carotene could play a role in modulating the LPS-induced TLR4 signaling pathway and in enhancing tight junction proteins. The findings will shed light on the role of β-carotene in colonic inflammation and also potentially in metabolic disorders since higher levels of LPS might induce features of metabolic diseases.

The stemness of hepatocytes is maintained by high levels of lipopolysaccharide via YAP1 activation

BackgroundThe liver possesses a powerful regeneration ability, which is correlated with the stemness of hepatocytes in the portal vein (PV). However, the mechanism underlying the maintenance of hepatocyte stemness has not been elucidated. Here, we hypothesized that high levels of lipopolysaccharide from the portal vein might maintain the stemness of hepatocytes in the PV area.MethodsFirst, we examined the location of hepatic stem cells and the concentration of lipopolysaccharide (LPS) in the portal vein and inferior vena cava. Then, we assessed the effect of LPS on stemness maintenance in mice by using antibiotics to eliminate LPS and knocking out the LPS receptor, TLR4. In vitro, the effect of LPS on the stemness of hepatocytes was investigated by colony and sphere formation assays and assessment of pluripotent and stem cell marker expression. Furthermore, we studied the mechanism by which LPS regulates the stemness of hepatocytes. Finally, we ligated the portal vein branch to further verify the effect of LPS.ResultsWe found that a high level of LPS from the portal vein was correlated with the location of hepatic stem cells in the PV area, and elimination of LPS by antibiotics inhibited the expression of the stemness marker. LPS promoted colony and sphere formation and induced the upregulation of pluripotent and stem cell markers in AML12 cells. Furthermore, in the reprogramming medium, LPS facilitated the dedifferentiation of mature hepatocytes into hepatic progenitor-like cells, which exhibited a bipotent differentiation capacity in vivo and in vitro. Mechanistically, LPS bound TLR4 to regulate stemness of hepatocytes via the activation of YAP1 signaling, and blockade of YAP1 abolished the LPS-induced cell stemness and upregulation of pluripotent markers.ConclusionsOur study implies a correlation between LPS/TLR4/YAP1 signaling and cell stemness, and LPS was shown to be involved in stemness maintenance of hepatocytes in the PV area. LPS might be used to induce the dedifferentiation of mature hepatocytes into progenitor-like cells for repair of liver injury.

Bacterial lipopolysaccharide is associated with stroke

We aimed to determine if plasma levels of bacterial lipopolysaccharide (LPS) and lipoteichoic acid (LTA) are associated with different causes of stroke and correlate with C-reactive protein (CRP), LPS-binding protein (LBP), and the NIH stroke scale (NIHSS). Ischemic stroke (cardioembolic (CE), large artery atherosclerosis (LAA), small vessel occlusion (SVO)), intracerebral hemorrhage (ICH), transient ischemic attack (TIA) and control subjects were compared (n = 205). Plasma LPS, LTA, CRP, and LBP levels were quantified by ELISA. LPS and CRP levels were elevated in ischemic strokes (CE, LAA, SVO) and ICH compared to controls. LBP levels were elevated in ischemic strokes (CE, LAA) and ICH. LTA levels were increased in SVO stroke compared to TIA but not controls. LPS levels correlated with CRP and LBP levels in stroke and TIA. LPS, LBP and CRP levels positively correlated with the NIHSS and WBC count but negatively correlated with total cholesterol. Plasma LPS and LBP associate with major causes of ischemic stroke and with ICH, whereas LPS/LBP do not associate with TIAs. LTA only associated with SVO stroke. LPS positively correlated with CRP, LBP, and WBC but negatively correlated with cholesterol. Higher LPS levels were associated with worse stroke outcomes.

Lipopolysaccharide Levels in Ex Vivo Lung Perfusion are Associated with Lung Function and Suitability for Transplantation

Purpose Ex vivo lung perfusion (EVLP) has emerged as an important platform to assess marginal donor lungs prior to transplantation. Derived from the outer membrane of gram-negative bacteria, lipopolysaccharide (LPS) can stimulate strong immune responses. Studies have shown that donor lungs infected with bacteria may have worse outcomes, suggesting bacteria-induced donor lung injury. However, no large-scale studies have looked at the relationship between LPS levels and donor lung performance on EVLP. Methods LPS levels were measured after one and four hours of perfusion in n=100 clinical EVLP cases. To assess the effects of LPS on lung inflammation, IL-6, 8, 10, and 1β, sTNF-R1, sTREM-1 and ET-1 levels were measured with an ELISA-based platform. Biochemical and physiological assessments were compared to LPS levels. Finally, LPS levels and recipient intensive care unit length of stay after transplantation were investigated. Results There was a significant increase from 0.14 [0.09-0.21] to 0.23 [0.13-0.38] EU/mL (p Conclusion This study demonstrates the trends and importance of circulating LPS levels during EVLP assessment of human donor lung injury. We show that high LPS levels and increasing levels over time were associated with poor donor lung performance in EVLP. These results support the need for therapeutic strategies to target LPS during EVLP, which may improve lung function and rescue more donor lungs for transplantation.

Abstract 15197: Lipopolysaccharide-Nuclear Factor-kappa B Pathway and Lipoprotein Apheresis Effects in Patients With Familial Hypercholesterolemia and Coronary Artery Disease

Introduction: Inflammation may play an important role in atherosclerosis in familial hypercholesterolemia (FH). Lipopolysaccharide (LPS)-nuclear factor-kappa B (NF-κB) pathway is a routine signal process activated in inflammatory status. Hypothesis: We assessed the hypothesis that LPS-NF-κB axis is markedly activated and lipoprotein apheresis has an inhibitory effect on this pathway in patients with FH and coronary artery disease (CAD). Methods: In this matched case-control study a genetically diagnosed FH cohort who presented stable CAD (n=63) was compared with 63 non-FH CAD and 63 non-FH non-CAD controls matched by sex and age. Plasma LPS levels and NF-κB activity were compared among the three groups. In addition, we studied in vitro LPS-induced interleukin-6 production by mononuclear cells from 16 FH cases without previous statin use and compared them with their respective matched control groups. Subsequently, these 16 FH patients underwent lipoprotein apheresis. Blood samples were taken immediately before and regularly after apheresis for measuring LPS and NF-κB. Results: FH plus CAD had higher LPS levels and NF-κB activity than CAD and non-CAD controls (all p &lt;0.01). LPS-induced interleukin-6 production by mononuclear cells of FH plus CAD was also much higher compared with CAD and non-CAD controls (both p &lt;0.01). Moreover, plasma LPS levels ( p &lt;0.001) and NF-κB activity ( p &lt;0.01) were dramatically reduced after apheresis in FH patients. Conclusions: In conclusion, genetically confirmed FH patients with CAD had a marked activation of LPS-NF-κB axis, while lipoprotein apheresis significantly attenuated this key inflammatory pathway, suggesting that inflammation may be an important therapeutic target for FH patients.

Bcl2 like protine-12 (Bcl2L12) facilitates experimental airway allergic inflammation by inducing autocrine eotaxin in eosinophils

BackgroundThe pathogenesis of airway allergic disorders (AAD) needs to be further investigated. Eosinophils (Eos) are the canonical effector cells in AAD attacks. Bcl2 like protein-12 (Bcl2L12) is an apoptosis inhibitor and an immune regulator. Eos have the defects of apoptosis. This study aims to investigate the role of Bcl2L12 in the AAD pathogenesis by regulating Eo activities. MethodsHuman nasal lavage fluids (NLF) and mouse bronchoalveolar lavage fluids (BALF) was collected. Eos in NLF and BALF were analyzed by flow cytometry. A murine AAD model was developed with ovalbumin as a specific antigen. ResultsWe found that Eos isolated from NLF or BALF of AAD subjects expressed high levels of Bcl2L12 and showed defects of apoptosis. The Bcl2L12 expression in Eos was positively correlated with the AAD response. High lipopolysaccharide levels were detected in the AAD airways, that promoted the Bcl2L12 expression in Eos. Bcl2L12 mediated the LPS-induced autocrine eotaxin 1 expression in Eos through activating the MAPK p38/STAT6/NF-κB signal pathway. Depletion of Bcl2L12 in Eos suppressed experimental AAD in mice. ConclusionsAAD Eos express high levels of Bcl2L12, the latter is associated with AAD response by regulating the autocrine eotaxin 1 in Eos. Depletion of Bcl2L12 in Eos attenuates experimental AAD, suggesting that to suppress the Bcl2L12 Eos has the translational potential in the treatment of AAD.