Eicosapentaenoic and docosahexaenoic acids in cultured rat ventricular myocytes and hypoxia-induced alterations of phospholipase?A activity

Abstract

Hypoxia was reported to induce a decrease in phosphatidylcholine-hydrolyzing phospholipase activity (PC-PLA) in cultured rat cardiomyocytes. This work was intended to compare the influence of the presence of either eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) in the phospholipids on the PC-PLA activity in normoxic and hypoxic conditions. The enrichment of the medium with EPA or DHA resulted in cell phospholipids containing about 2% or 22% DHA, respectively. These cells were then submitted for 3.5 h to either normoxia or hypoxia and the PC-PLA activities were assayed using [1-14C] dioleoyl-PC (pH 8.4 for PC-PLA2 and 4.9 for PC-PLA1). The results show that both enzymic activities are significantly higher in DHA-rich cardiomyocytes. Hypoxia induced a significant decrease in PC-PLA2 (about 25%) which was not statistically different between the two groups of cells. The hypoxia-induced decrease in PC-PLA1 was not found significant. In conclusion, the nature of the long chain n-3 polyunsaturated fatty acids in the phospholipids appears to contribute to the regulation of PC-PLA activity but not to influence its decrease during hypoxia.

Membrane docosahexaenoic acid vs. eicosapentaenoic acid and the beating function of the cardiomyocyte and its regulation through the adrenergic receptors

“…The cells were grown in a standard culture medium [Ham's FI0 (Seromed Biochrom, Berlin, Germany) medium supplemented with 10% fetal calf serum and 10% human serum] in a humidified atmosphere at 37~ containing 5% CO 2. After 24 h, the cells were incubated for four days in the same medium supplemented as serum albumin-bound fatty acids with either 20:5n-3 (EPA) or 22:6n-3 (DHA), which led to two populations (EPA and DHA cells) from the same cell pool (23).…”

Effects of omega-3 polyunsaturated fatty acids on cardiac myocyte protection

“…However, the change of fatty acid composition of cardiomyocytes membrane can also affect the behavior of receptors as well as of transporters and enzymes inserted in the lipid layer. It was shown that cardiomyocytes membrane fluidity was increased following addition of DHA, EPA and ALA (15) and that the type of the long chain omega-3 PUFAs in the phospholipids played a role in the regulation of phosphatidylcholine-hydrolyzing phospholipase activity (31). Activation of the PKA pathway by EPA administration on rat ventricular myocytes was also proved.…”