Aneurysm miRNA Signature Differs,Depending on Disease Localization and Morphology

Limited comprehension of aneurysm pathology has led to inconclusive results from clinical trials. miRNAs are key regulators of post-translational gene modification and are useful tools in elucidating key features of aneurysm pathogenesis in distinct entities of abdominal and popliteal aneurysms. Here, surgically harvested specimens from 19 abdominal aortic aneurysm (AAA) and 8 popliteal artery aneurysm (PAA) patients were analyzed for miRNA expression and histologically classified regarding extracellular matrix (ECM) remodeling and inflammation. DIANA-based computational target prediction and pathway enrichment analysis verified our results, as well as previous ones. miRNA-362, -19b-1, -194, -769, -21 and -550 were significantly down-regulated in AAA samples depending on degree of inflammation. Similar or inverse regulation was found for miR-769, 19b-1 and miR-550, -21, whereas miR-194 and -362 were unaltered in PAA. In situ hybridization verified higher expression of miR-550 and -21 in PAA compared to AAA and computational analysis for target genes and pathway enrichment affirmed signal transduction, cell-cell-interaction and cell degradation pathways, in line with previous results. Despite the vague role of miRNAs for potential diagnostic and treatment purposes, the number of candidates from tissue signature studies is increasing. Tissue morphology influences subsequent research, yet comparison of distinct entities of aneurysm disease can unravel core pathways.     

A comparison of the lipid compositions of the lipoproteins of the intestinal and popliteal lymph and plasma of sheep

The lipids and lipoproteins of intestinal lymph in the sheep make a contribution to the corresponding fractions in plasma and thence affect lipid compositions in other tissues. As a first step towards assessing this contribution, the lipoproteins of intestinal lymph, peripheral (popliteal lymph) and plasma have been isolated for compositional studies. Popliteal lymph and the plasma were similar in the distributions of lipids among the major lipoprotein fractions with high-density lipoproteins accounting for just over half of the total lipid present. In intestinal lymph, 80 per cent of the total lipid was associated with the very low-density lipoprotein fraction. Whereas triacylglycerols comprised the principal lipid component of the very low-density lipoprotein and low-density lipoprotein fractions of the intestinal lymph and were present in the high-density lipoprotein fraction, they were present in essence only in the very low-density lipoprotein fraction of popliteal lymph and plasma, where high concentrations of cholesteryl esters and phospholipids were found in all the lipoprotein fractions. The fatty acid compositions of each lipid class were also determined. The most distinctive feature of the results was the distribution of the essential fatty acid, linoleic acid, among the lipid components. In all lipid classes in each of the body fluids, the concentration of this component was highest in the high-density lipoproteins and lowest in the very low-density lipoproteins. Higher concentrations tended to be present in the triacylglycerols and phosphatidylcholine fractions of intestinal lymph than of plasma and popliteal lymph, but the opposite was true of the cholesteryl esters. The results are discussed in terms of the sources of the linoleic acid in the lipids of intestinal lymph of ruminant animals.