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Western diet enhances hepatic inflammation in mice exposed to cecal ligation and puncture.

Rivera CA, Gaskin L, Singer G, Houghton J, Allman M - BMC Physiol. (2010)

Bottom Line: Therefore, we hypothesized that the combined effects of sepsis and feeding WD on TRL-4 signaling would exacerbate hepatic inflammation.To demonstrate the direct effect of saturated fatty acid on hepatocytes, C3A human hepatocytes were cultured in medium containing 100 μM palmitic acid (PA).In addition, PA stimulated the static adhesion of U937 monocytes to C3A cells, a phenomenon blocked by inclusion of an anti-TLR-4/MD2 antibody in the culture medium.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA, USA. crive1@lsuhsc.edu

ABSTRACT

Background: Obese patients display an exaggerated morbidity during sepsis. Since consumption of a western-style diet (WD) is a major factor for obesity in the United States, the purpose of the present study was to examine the influence of chronic WD consumption on hepatic inflammation in mice made septic via cecal ligation and puncture (CLP). Feeding mice diets high in fat has been shown to enhance evidence of TLR signaling and this pathway also mediates the hepatic response to invading bacteria. Therefore, we hypothesized that the combined effects of sepsis and feeding WD on TRL-4 signaling would exacerbate hepatic inflammation. Male C57BL/6 mice were fed purified control diet (CD) or WD that was enriched in butter fat (34.4% of calories) for 3 weeks prior to CLP. Intravital microscopy was used to evaluate leukocyte adhesion in the hepatic microcirculation. To demonstrate the direct effect of saturated fatty acid on hepatocytes, C3A human hepatocytes were cultured in medium containing 100 μM palmitic acid (PA). Quantitative real-time PCR was used to assess mRNA expression of tumor necrosis factor-alpha (TNF-α, monocyte chemotactic protein-1 (MCP-1), intercellular adhesion molecule-1 (ICAM-1), toll-like receptor-4 (TLR-4) and interleukin-8 (IL-8).

Results: Feeding WD increased firm adhesion of leukocytes in the sinusoids and terminal hepatic venules by 8-fold six hours after CLP; the increase in platelet adhesion was similar to the response observed with leukocytes. Adhesion was accompanied by enhanced expression of TNF-α, MCP-1 and ICAM-1. Messenger RNA expression of TLR-4 was also exacerbated in the WD+CLP group. Exposure of C3A cells to PA up-regulated IL-8 and TLR-4 expression. In addition, PA stimulated the static adhesion of U937 monocytes to C3A cells, a phenomenon blocked by inclusion of an anti-TLR-4/MD2 antibody in the culture medium.

Conclusions: These findings indicate a link between obesity-enhanced susceptibility to sepsis and consumption of a western-style diet.

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Related in: MedlinePlus

Static adhesion of monocytes to palmitic acid -treated C3A hepatocytes. C3A cells were treated with PA (100 mM) or PA + anti-TLR-4 blocking antibody (2 μg/ml). After 24h U937 monocytes were allowed to settle on the C3A monolayer and the number of firmly adherent cells was determined following inversion of the co-cultures. Data are presented as mean SEM of 4 experiments. *p < 0.05 compared to vehicle control cultures; #p < 0.05 compared to palmitate alone.
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Figure 6: Static adhesion of monocytes to palmitic acid -treated C3A hepatocytes. C3A cells were treated with PA (100 mM) or PA + anti-TLR-4 blocking antibody (2 μg/ml). After 24h U937 monocytes were allowed to settle on the C3A monolayer and the number of firmly adherent cells was determined following inversion of the co-cultures. Data are presented as mean SEM of 4 experiments. *p < 0.05 compared to vehicle control cultures; #p < 0.05 compared to palmitate alone.

Mentions: To investigate the potential importance of TLR-4 in the pro-inflammatory condition resulting from PA, a static adhesion assay was performed in which one experimental series included C3A cells pretreated with an anti-TLR-4/MD2 blocking antibody. Following stimulation of C3A cells with PA, U937 cells were allowed to settle on the C3A monolayer and the number of firmly adherent cells was determined following inversion of the co-cultures. A minimal number of U937 cells were observed to adhere to mock-stimulated C3A cells (Figure 6). Consistent with in vivo video microscopy results, PA potentiated adhesion by approximately 60% above control values. This response was largely blocked by addition of the TLR-4/MD2 blocking antibody.


Western diet enhances hepatic inflammation in mice exposed to cecal ligation and puncture.

Rivera CA, Gaskin L, Singer G, Houghton J, Allman M - BMC Physiol. (2010)

Static adhesion of monocytes to palmitic acid -treated C3A hepatocytes. C3A cells were treated with PA (100 mM) or PA + anti-TLR-4 blocking antibody (2 μg/ml). After 24h U937 monocytes were allowed to settle on the C3A monolayer and the number of firmly adherent cells was determined following inversion of the co-cultures. Data are presented as mean SEM of 4 experiments. *p < 0.05 compared to vehicle control cultures; #p < 0.05 compared to palmitate alone.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2984476&req=5

Figure 6: Static adhesion of monocytes to palmitic acid -treated C3A hepatocytes. C3A cells were treated with PA (100 mM) or PA + anti-TLR-4 blocking antibody (2 μg/ml). After 24h U937 monocytes were allowed to settle on the C3A monolayer and the number of firmly adherent cells was determined following inversion of the co-cultures. Data are presented as mean SEM of 4 experiments. *p < 0.05 compared to vehicle control cultures; #p < 0.05 compared to palmitate alone.
Mentions: To investigate the potential importance of TLR-4 in the pro-inflammatory condition resulting from PA, a static adhesion assay was performed in which one experimental series included C3A cells pretreated with an anti-TLR-4/MD2 blocking antibody. Following stimulation of C3A cells with PA, U937 cells were allowed to settle on the C3A monolayer and the number of firmly adherent cells was determined following inversion of the co-cultures. A minimal number of U937 cells were observed to adhere to mock-stimulated C3A cells (Figure 6). Consistent with in vivo video microscopy results, PA potentiated adhesion by approximately 60% above control values. This response was largely blocked by addition of the TLR-4/MD2 blocking antibody.

Bottom Line: Therefore, we hypothesized that the combined effects of sepsis and feeding WD on TRL-4 signaling would exacerbate hepatic inflammation.To demonstrate the direct effect of saturated fatty acid on hepatocytes, C3A human hepatocytes were cultured in medium containing 100 μM palmitic acid (PA).In addition, PA stimulated the static adhesion of U937 monocytes to C3A cells, a phenomenon blocked by inclusion of an anti-TLR-4/MD2 antibody in the culture medium.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA, USA. crive1@lsuhsc.edu

ABSTRACT

Background: Obese patients display an exaggerated morbidity during sepsis. Since consumption of a western-style diet (WD) is a major factor for obesity in the United States, the purpose of the present study was to examine the influence of chronic WD consumption on hepatic inflammation in mice made septic via cecal ligation and puncture (CLP). Feeding mice diets high in fat has been shown to enhance evidence of TLR signaling and this pathway also mediates the hepatic response to invading bacteria. Therefore, we hypothesized that the combined effects of sepsis and feeding WD on TRL-4 signaling would exacerbate hepatic inflammation. Male C57BL/6 mice were fed purified control diet (CD) or WD that was enriched in butter fat (34.4% of calories) for 3 weeks prior to CLP. Intravital microscopy was used to evaluate leukocyte adhesion in the hepatic microcirculation. To demonstrate the direct effect of saturated fatty acid on hepatocytes, C3A human hepatocytes were cultured in medium containing 100 μM palmitic acid (PA). Quantitative real-time PCR was used to assess mRNA expression of tumor necrosis factor-alpha (TNF-α, monocyte chemotactic protein-1 (MCP-1), intercellular adhesion molecule-1 (ICAM-1), toll-like receptor-4 (TLR-4) and interleukin-8 (IL-8).

Results: Feeding WD increased firm adhesion of leukocytes in the sinusoids and terminal hepatic venules by 8-fold six hours after CLP; the increase in platelet adhesion was similar to the response observed with leukocytes. Adhesion was accompanied by enhanced expression of TNF-α, MCP-1 and ICAM-1. Messenger RNA expression of TLR-4 was also exacerbated in the WD+CLP group. Exposure of C3A cells to PA up-regulated IL-8 and TLR-4 expression. In addition, PA stimulated the static adhesion of U937 monocytes to C3A cells, a phenomenon blocked by inclusion of an anti-TLR-4/MD2 antibody in the culture medium.

Conclusions: These findings indicate a link between obesity-enhanced susceptibility to sepsis and consumption of a western-style diet.

Show MeSH
Related in: MedlinePlus