Synthesis and secretion of apo B containing lipoproteins by primary cultures of hepatocytes isolated from rats fed atherogenic diet

Ábrahám, Rita; Kumar, N. Suresh; Kumar, Gyanendra; Sudhakaran, P. R.; Kurup, Parameswara Achutha

doi:10.1016/0021-9150(93)90069-7

Cited by 5 publications

(6 citation statements)

References 25 publications

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“…Triglyceride levels were found to be greatly reduced in HFD + Se fed group in comparison to HFD fed group. These findings suggest the hypercholesterolemic state as reported earlier [40-42]. The selenium potential against hypercholesterolemia is supported by some other research groups as well [41,43].…”

Section: Discussionsupporting

confidence: 88%

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Studies on HDL associated enzymes under experimental hypercholesterolemia: possible modulation on selenium supplementation

Kaur

Bansal

2009

Lipids Health Dis

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BackgroundAtherosclerosis is a chronic disorder of the arterial wall that starts by formation of fatty streaks and gradually evolves into atherosclerotic plaques. High-density lipoproteins (HDL) blood levels are inversely correlated with atherosclerosis. This beneficial effect of HDL has been partly attributed to its antioxidant properties mediated by paraoxonase1 (PON1) or platelet-activating factor acetylhydrolase (PAF-AH). The present study was aimed to study HDL associated enzymes i.e. PON1 and PAF-AH under experimental hypercholesterolemia and their possible modulation on selenium (Se; an antioxidant) supplementation. Male Sprague Dawley rats were divided into three groups and fed on the control diet, high fat diet (HFD) and HFD + Se respectively for the period of 4 months.ResultsCholesterol, triglycerides, HDL and LDL levels were significantly increased by HFD feeding. Selenium supplementation lowered the triglyceride level, whereas the other lipid values remained unchanged. Serum selenium levels were reduced by 31% and ROS levels in the liver were 2-fold increased by HFD. Se supplementation, however, diminished the HFD-induced ROS levels by 29%. Furthermore, Se also improved the HFD-mediated reduction of serum PON1 enzyme activity by 34% and PON1 protein levels by 21%. However, no significant effect of Se was detected on the reduced PAF-AH proteins levels in HFD fed rats. mRNA expression of PON1 and PAF-AH in the liver was not affected in the Se treated groups.ConclusionSe supplementation appears to be protective in hypercholesterolemia by restoring the antioxidant properties of the HDL associated enzyme i.e. PON1 whereas biological system aims towards maintaining the same PAF-AH levels even on selenium supplementation indicating its probable role in both anti and pro-atherogenic activities. Therefore, Se supplementation might be a valuable approach to limit the adverse effects of hypercholesterolemia and may need further investigations.

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Section: Discussionsupporting

confidence: 88%

“…control diet, HFD was prepared in the laboratory itself according to the composition given by Abraham et al [59] Table 3.…”

Section: Methodsmentioning

confidence: 99%

Studies on HDL associated enzymes under experimental hypercholesterolemia: possible modulation on selenium supplementation

Kaur

Bansal

2009

Lipids Health Dis

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“…These findings suggest the hypercholesterolemic state as reported earlier [39][40][41]. Total cholesterol/HDL ratio is considered to be most predictive for atherosclerosis [23,42]. Greater is the ratio, greater the risk for a clinical event [43].…”

Section: Resultsmentioning

confidence: 59%

“…Compelling evidences too indicate the importance of the type of fats than the total amount of the fats with respect to the risk of the cardiovascular diseases [23]. Defects in the cholesterol metabolism are one of the major causes of cardiovascular disorders [24] and large increase in plasma cholesterol leads to premature atherosclerosis [4].…”

Section: Resultsmentioning

confidence: 99%

Studies on Scavenger Receptors under Experimental Hypercholesterolemia: Modulation on Selenium Supplementation

Kaur

Bansal

2010

Biol Trace Elem Res

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Scavenger receptors (SR) are the cell surface proteins that can bind and internalize modified lipoproteins. Because ox-LDL seems to play a key role in foam cell formation during atherogenesis, SR may be critical for pathogenesis of atherosclerosis. The present study was aimed to study the effect of selenium (Se) supplementation on SR, i.e., SRB1 and CD36 under experimental hypercholesterolemia. Male Sprague Dawley rats were divided into three groups and fed on the control diet, high cholesterol diet (HCD), and HCD + Se, respectively, for a period of 4 months. Selenium and reactive oxygen species (ROS) levels were estimated in serum and liver respectively. mRNA expression using RT-PCR and protein expression using ELISA were analyzed for SRB1 and CD36 receptors. Selenium levels decreased whereas ROS levels increased under experimental hypercholesterolemic state. Selenium supplementation (1 ppm), however, diminished the HCD-induced ROS levels. Furthermore, the protein expression of SRB1 was significantly reduced in HCD group in comparison to the control group. On the other hand, HCD-induced increase in CD36 mRNA and protein expression decreased significantly on Se supplementation. In conclusion, CD36 receptors seem to play a pro-atherogenic role under hypercholesterolemic state. Selenium supplementation, in addition, might prove to be a therapeutically valuable approach in near future to limit the adverse effect of hypercholesterolemia.

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“…In addition to the requirements of lipid components, the synthesis of VLDL is dependent on the supply of apoB in the liver (31). Accordingly under the conditions when hepatic VLDL secretion is stimulated, the amount of newly synthesized apoB is increased and so is the amount secreted by the liver (32). Conversely, decreased hepatic secretion of VLDL is accompanied by a reduction of apoB secretion (31).…”

Section: Discussionmentioning

confidence: 99%

Stearic acid modifies very low density lipoprotein lipid composition and particle size differently from shorter‐chain saturated fatty acids in cultured rat hepatocytes

Pai

Yeh

1997

Lipids

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Stearic acid as compared to myristate, palmitate, or oleate is poorly incorporated into triacylglycerol, a major lipid component of very low density lipoprotein (VLDL). The present study investigated the effects of these fatty acids on VLDL metabolism in cultured rat hepatocytes. All fatty acids stimulated [2-3H] glycerol incorporation into VLDL lipids and secretion of [3H]-labeled VLDL by hepatocytes. However, the rate of [3H]-labeled VLDL secretion in the presence of nonlabeled stearate (12.8 +/- 0.7 pmol/mg protein/4 h) was 46, 59, and 22% of that observed for those treated with myristate, palmitate, and oleate, respectively. [1-14C]Stearate as a substrate was also less effective than other labeled fatty acids to be incorporated into VLDL lipids. Of total VLDL lipids synthesized from [1-14C] stearate, triacylglycerol accounted for 78% as compared to 88-97% of that derived from palmitate, myristate, and oleate. The amounts of apoB100 and apoB48 were the same in hepatocytes treated with or without exogenous fatty acids. Similarly, the rate of apoB synthesis from [35S] methionine was not affected by exogenous fatty acids. The treatment of cells with various saturated fatty acids increased the particle size of VLDL to different extents. The largest particles of VLDL, with a mean diameter of 79.3 +/- 11.9 nm, were seen in the cells treated with stearate, followed by those treated with palmitate and myristate (45.5 +/- 9.8 and 38.6 +/- 6.8 nm, diameter, respectively). Clearly, hepatocytes treated with stearate secrete less VLDL and produce larger VLDL particles than those treated with shorter-chain saturated fatty acids.

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Synthesis and secretion of apo B containing lipoproteins by primary cultures of hepatocytes isolated from rats fed atherogenic diet

Cited by 5 publications

References 25 publications

Studies on HDL associated enzymes under experimental hypercholesterolemia: possible modulation on selenium supplementation

Studies on HDL associated enzymes under experimental hypercholesterolemia: possible modulation on selenium supplementation

Studies on Scavenger Receptors under Experimental Hypercholesterolemia: Modulation on Selenium Supplementation

Stearic acid modifies very low density lipoprotein lipid composition and particle size differently from shorter‐chain saturated fatty acids in cultured rat hepatocytes

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