Partitioning of Rumen-Protected n-3 and n-6 Fatty Acids is Organ-Specific in Growing Angus Heifers.

Dietary polyunsaturated fatty acids (PUFA), especially n-3 and n-6 fatty acids (FA), play an important role in the regulation of FA metabolism in all mammals. However, FA metabolism differs between different organs, suggesting a distinct partitioning of highly relevant FA. For the present study in cattle, a novel technology was applied to overcome rumen biohydrogenation of dietary unsaturated FA. Angus heifers were fed a straw-based diet supplemented for 8 weeks with 450 g/day of rumen-protected oil, either from fish (FO) or sunflower (SO). The FA composition in blood and five important organs, namely heart, kidney, liver, lung, and spleen, was examined. In blood, proportions of polyunsaturated FA were increased by supplementing FO compared to SO. The largest increase of eicosapentaenoic acid (EPA) proportion was found with FO instead of SO in the kidney, the lowest in the lung. Docosahexaenoic acid (DHA) was increased more in the liver than in kidney, lung, and spleen. The heart incorporated seven times more EPA than DHA, which is more than all other organs and described here for the first time in ruminants. In addition, the heart had the highest proportions of α-linolenic acid (18:3n-3) and linoleic acid (18:2n-6) of all organs. The proportions of polyunsaturated FA in the lung and spleen were exceptionally low compared to heart, liver, and kidney. In conclusion, it was shown that the response to FO in the distribution of dietary n-3 FA was organ-specific while proportions of n-6 FA were quite inert with respect to the type of oil supplemented.

The Expression of Lipoprotein Receptors Is Increased in the Infarcted Area After Myocardial Infarction Induced in Rats With Cardiac Dysfunction.

Left ventricular (LV) remodeling after myocardial infarction constitutes the structural basis for ventricular dysfunction and heart failure. The characterization underlying the expression of lipoprotein receptors in cardiac dysfunction is scarcely explored. The aim of this study was to analyze the status of lipoprotein receptors on the infarcted and noninfarcted areas of LV and to verify whether nanoparticles that mimic the lipid structure of low-density lipoprotein (LDL) and have the ability to bind to LDL receptors (LDE) are taken up more avidly by the noninfarcted LV. 13 male Wistar rats with left coronary artery ligation (myocardial infarction [MI]) and 12 animals with SHAM operation (SHAM) were used in this study. 6 weeks after the procedure, the quantification of low-density lipoprotein receptor (LDLR), LDL receptor-related protein 1 (LRP1), scavenger receptor-class B type I (SR-BI) lipoprotein receptors, and PCNA proliferation marker, and tissue uptake of radioactively labeled LDE were performed. Immunohistochemistry and Western blot analysis showed that LDLR, LRP1, SR-BI, and PCNA, expression in infarcted area of MI was remarkably higher than SHAM and noninfarcted subendocardial (SEN) and interstitial (INT) areas. In addition, in SEN noninfarcted area of MI, the presence of LDLR was about threefold higher than in SHAM SEN and INT noninfarcted areas. The LDE uptake of noninfarcted LV of MI group was about 30% greater than that of SHAM group. In conclusion, these findings regarding the status of lipoprotein receptors after MI induction could help to establish mechanisms on myocardial repairing. In conclusion, infarcted rats with LV dysfunction showed increased expression of lipoprotein receptors mainly in the infarcted area.

Berberine Inhibits Oxygen Consumption Rate Independent of Alteration in Cardiolipin Levels in H9c2 Cells.

Small clinical studies have shown that oral treatment with the plant alkaloid berberine (BBR) reduces blood glucose levels similar to that of metformin and have promoted its use as a novel anti-diabetic therapy. However, in vitro studies have shown that high concentrations of BBR potently inhibit cell proliferation through inhibition of mitochondrial function. Cardiolipin (Ptd2Gro) is a key phospholipid required for regulating mitochondrial bioenergetic function. We examined if BBR inhibited oxygen consumption rate in H9c2 cardiac myocytes through alteration in Ptd2Gro metabolism. Treatment of H9c2 cells with BBR resulted in a rapid (within minutes) concentration-dependent decrease in the oxygen consumption rate (OCR) as determined using a Seahorse XF24 analyzer. Concentrations of BBR as low as 1 µM were effective in inhibiting OCR. In addition, all concentrations of BBR inhibited the fatty acid-mediated increase in OCR that was observed in untreated cells. Treatment of H9c2 cells with up to 25 µM BBR for 24 h markedly reduced [3H]thymidine incorporation into cells but did not alter the pool size of Ptd2Gro. In contrast, 12.5 µM BBR increased [1-14C]palmitate incorporation into Ptd2Gro and 12.5 µM and 25 µM BBR reduced [1-14C]oleate incorporation into Ptd2Gro. Protein kinase C delta (PKCδ) activation through its increased membrane association is known to alter Ptd2Gro distribution within mitochondria. BBR treatment resulted in a decrease in membrane-associated PKCδ and attenuated the palmitate-mediated increase in PKCδ membrane-association. Thus, BBR treatment of H9c2 cardiac myocytes inhibits cellular OCR independent of alteration in Ptd2Gro levels.