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Intestinal mucosal triacylglycerol accumulation secondary to decreased lipid secretion in obese and high fat fed mice.

Douglass JD, Malik N, Chon SH, Wells K, Zhou YX, Choi AS, Joseph LB, Storch J - Front Physiol (2012)

Bottom Line: Fewer changes were found in mucosal samples from the fasted state animals.Remarkably, oral fat tolerance tests showed a striking reduction in the plasma appearance of an oral fat load in the ob/ob and WT-HF mice compared to WT-LF.Moreover, even in the absence of frank obesity, HF feeding leads to a large decrease in the rate of intestinal lipid secretion.

View Article: PubMed Central - PubMed

Affiliation: Department of Nutritional Sciences, School of Environmental and Biological Sciences, Rutgers University New Brunswick, NJ, USA.

ABSTRACT
The ectopic deposition of fat in liver and muscle during obesity is well established, however surprisingly little is known about the intestine. We used the ob/ob mouse and C57BL6/J mice fed a high fat (HF) diet to examine the effects of obesity and the effects of HF feeding, respectively, on intestinal mucosal triacylglycerol (TG) accumulation. Male C57BL6/J (wild-type, WT) mice were fed low fat (LF; 10% kcal as fat) or HF (45%) diets, and ob/ob mice were fed the LF diet, for 3 weeks. In this time frame, the WT-HF mice did not become obese, enabling independent examination of effects of the HF diet and effects of obesity. Analysis of intestinal lipid extracts from fed and fasted animals demonstrated that the mucosa, like other tissues, accumulates excess lipid. In the fed state, mucosal triacylglycerol (TG) levels were threefold and fivefold higher in the WT-HF and ob/ob mice, respectively, relative to the WT-LF mice. In the fasted state, mucosa from ob/ob mice had threefold higher TG levels relative to WT-LF mucosa. q-PCR analysis of mucosal mRNA from fed state mice showed alterations in the expression of several genes related to both anabolic and catabolic lipid metabolism pathways in WT-HF and ob/ob mice relative to WT-LF controls. Fewer changes were found in mucosal samples from the fasted state animals. Remarkably, oral fat tolerance tests showed a striking reduction in the plasma appearance of an oral fat load in the ob/ob and WT-HF mice compared to WT-LF. Overall, the results demonstrate that the intestinal mucosa accumulates excess TG during obesity. Changes in the expression of lipid metabolic and transport genes, as well as reduced secretion of dietary lipid from the mucosal cells into the circulation, may contribute to the TG accumulation in intestinal mucosa during obesity. Moreover, even in the absence of frank obesity, HF feeding leads to a large decrease in the rate of intestinal lipid secretion.

No MeSH data available.


Related in: MedlinePlus

Lipid accumulation in fed state proximal intestinal mucosa. (A) LF-fed WT mice (B) HF fed WT mice (C) LF-fed ob/ob mice. 40× magnification, 10 μm section, ORO, and H&E stain, as described in Section “Materials and Methods.”
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Figure 3: Lipid accumulation in fed state proximal intestinal mucosa. (A) LF-fed WT mice (B) HF fed WT mice (C) LF-fed ob/ob mice. 40× magnification, 10 μm section, ORO, and H&E stain, as described in Section “Materials and Methods.”

Mentions: Neutral lipid accumulation in duodenal sections from the proximal small intestine of fed mice was visualized using ORO staining. In keeping with the biochemical analysis, pronounced staining was observed in ob/ob mucosa, and greater staining was found in WT–HF compared to WT–LF mucosa (Figures 3A–C). We noticed during sectioning and histological preparation that the ob/ob mucosal samples were more fragile than either of the WT samples, as seen by decreased mucosal integrity (Figure 3C).


Intestinal mucosal triacylglycerol accumulation secondary to decreased lipid secretion in obese and high fat fed mice.

Douglass JD, Malik N, Chon SH, Wells K, Zhou YX, Choi AS, Joseph LB, Storch J - Front Physiol (2012)

Lipid accumulation in fed state proximal intestinal mucosa. (A) LF-fed WT mice (B) HF fed WT mice (C) LF-fed ob/ob mice. 40× magnification, 10 μm section, ORO, and H&E stain, as described in Section “Materials and Methods.”
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3285813&req=5

Figure 3: Lipid accumulation in fed state proximal intestinal mucosa. (A) LF-fed WT mice (B) HF fed WT mice (C) LF-fed ob/ob mice. 40× magnification, 10 μm section, ORO, and H&E stain, as described in Section “Materials and Methods.”
Mentions: Neutral lipid accumulation in duodenal sections from the proximal small intestine of fed mice was visualized using ORO staining. In keeping with the biochemical analysis, pronounced staining was observed in ob/ob mucosa, and greater staining was found in WT–HF compared to WT–LF mucosa (Figures 3A–C). We noticed during sectioning and histological preparation that the ob/ob mucosal samples were more fragile than either of the WT samples, as seen by decreased mucosal integrity (Figure 3C).

Bottom Line: Fewer changes were found in mucosal samples from the fasted state animals.Remarkably, oral fat tolerance tests showed a striking reduction in the plasma appearance of an oral fat load in the ob/ob and WT-HF mice compared to WT-LF.Moreover, even in the absence of frank obesity, HF feeding leads to a large decrease in the rate of intestinal lipid secretion.

View Article: PubMed Central - PubMed

Affiliation: Department of Nutritional Sciences, School of Environmental and Biological Sciences, Rutgers University New Brunswick, NJ, USA.

ABSTRACT
The ectopic deposition of fat in liver and muscle during obesity is well established, however surprisingly little is known about the intestine. We used the ob/ob mouse and C57BL6/J mice fed a high fat (HF) diet to examine the effects of obesity and the effects of HF feeding, respectively, on intestinal mucosal triacylglycerol (TG) accumulation. Male C57BL6/J (wild-type, WT) mice were fed low fat (LF; 10% kcal as fat) or HF (45%) diets, and ob/ob mice were fed the LF diet, for 3 weeks. In this time frame, the WT-HF mice did not become obese, enabling independent examination of effects of the HF diet and effects of obesity. Analysis of intestinal lipid extracts from fed and fasted animals demonstrated that the mucosa, like other tissues, accumulates excess lipid. In the fed state, mucosal triacylglycerol (TG) levels were threefold and fivefold higher in the WT-HF and ob/ob mice, respectively, relative to the WT-LF mice. In the fasted state, mucosa from ob/ob mice had threefold higher TG levels relative to WT-LF mucosa. q-PCR analysis of mucosal mRNA from fed state mice showed alterations in the expression of several genes related to both anabolic and catabolic lipid metabolism pathways in WT-HF and ob/ob mice relative to WT-LF controls. Fewer changes were found in mucosal samples from the fasted state animals. Remarkably, oral fat tolerance tests showed a striking reduction in the plasma appearance of an oral fat load in the ob/ob and WT-HF mice compared to WT-LF. Overall, the results demonstrate that the intestinal mucosa accumulates excess TG during obesity. Changes in the expression of lipid metabolic and transport genes, as well as reduced secretion of dietary lipid from the mucosal cells into the circulation, may contribute to the TG accumulation in intestinal mucosa during obesity. Moreover, even in the absence of frank obesity, HF feeding leads to a large decrease in the rate of intestinal lipid secretion.

No MeSH data available.


Related in: MedlinePlus