Combined incubation of cadmium, docosahexaenoic and eicosapentaenoic acid results in increased uptake of cadmium and elevated docosapentaenoic acid content in hepatocytes in vitro.

Pavla Linhartova,Sabine Sampels

doi:10.1186/s12944-015-0159-2

Pavla Linhartova, Sabine Sampels

Open Access

https://doi.org/10.1186/s12944-015-0159-2

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Abstract

BackgroundHuman hepatocellular cells Hep G2 were used to mimic and investigate the effect of the intake of cadmium (Cd2+) contaminated fish on cytotoxicity, fatty acid (FA) and phospholipid class composition.MethodsCells were incubated with a combination of Cd2+ and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) fish specific FA.ResultsWe measured a significant increased proportion of EPA and DHA in the treated cells compared to the control line confirming the uptake. While doses of 25 μM DHA showed to be toxic to the cells, repeated short term incubations (2 h) at lower doses resulted in an increased uptake of DHA. The resarzurin assay, evaluating cell viability, showed a significant decrease in cell viability between Cd2+ incubation time and, further, the pre-incubation with BSA-FA complex resulted in significantly increased cell viability. On the metabolic level, increased concentrations of EPA and DHA resulted in an increased proportion of docosapentaenoic acid (DPA) which indicated an increased metabolism. Also 24-h combined incubations of 5 μM Cd2+ and EPA and DHA showed a significant increase DPA in the total lipid fraction of the cells. In addition, incubation with 5 μM Cd2+ for 24 h also decreased the total cardiolipin (CL) fraction from the identified phospholipids.ConclusionsWe confirmed that the applied FA were taken up by the cells. A combination of EPA, DHA and Cd2+ influenced lysosomal integrity, cell viability and lipid metabolism in the cells. The most important finding is that DHA and EPA reduced the detrimental effect of Cd2+ on cell viability. The exact effects and kinetics behind our observations still need further evaluation.

Highlights

Human hepatocellular cells Hep G2 were used to mimic and investigate the effect of the intake of cadmium (Cd2+) contaminated fish on cytotoxicity, fatty acid (FA) and phospholipid class composition
In order to mimic the uptake of contaminated fish, we investigated the metabolic effects of cadmium (Cd2+) on the cell line Hep G2 in combination with the long chain n-3 polyunsaturated fatty acids (PUFA), eicosapentaenoic acid (EPA; 20:5 n-3) and docosahexaenoic acid (DHA; 22:6 n-3) which are typical for fish [19, 20]
The combination of 40 μM EPA+ 75 μM DHA resulted in a cell viability significantly below 50 % (18.9 % viable cells), while the combination of 10 μM EPA+ 20 μM DHA, was above the level IC70 (85.3 % vital cells) (Fig. 2), but was significantly lower compared to the control cells without added FA

Summary

Introduction

Human hepatocellular cells Hep G2 were used to mimic and investigate the effect of the intake of cadmium (Cd2+) contaminated fish on cytotoxicity, fatty acid (FA) and phospholipid class composition. The health benefits from eating fish, partly attributable to omega-3 polyunsaturated fatty acids (n-3 PUFA), are well documented both for prenatal development and. Based on ISIRI, the tolerable daily intake for Cd2+ is 1 μg/day kg of Linhartova and Sampels Lipids in Health and Disease (2015) 14:156 bw (body weight), [7]. Cd2+ compounds have toxic effects on the kidney and are assumed to be neurotoxic. These effects could be due to oxidative stress, and by different mechanisms that affect the cell membrane composition [11, 12]. Cd2+ acts as a catalyst during the formation of reactive oxygen species (ROS)

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