The Role of Hypertriglyceridemia in the Development of Atherosclerosis and Endothelial Dysfunction

A hereditary postprandial hypertriglyceridemic rabbit (PHT rabbit) is a new dyslipidemic model showing remarkably high plasma triglycerides with only limited elevation of plasma total cholesterol. In PHT rabbits, plasma triglyceride was markedly elevated postprandially compared with healthy Japanese white (JW) rabbits. In physiological experiments, the ring preparation of the thoracic aorta was suspended in an organ bath filled with modified Krebs-Henseleit solution, and the developed tension was recorded. Endothelial function was evaluated by acetylcholine-induced vasorelaxation in each preparation with intact endothelium. The acetylcholine-induced endothelium-dependent relaxation was diminished in PHT compared with JW rabbits, suggesting endothelial dysfunction in PHT rabbits. Histological examination was carried out in adipose tissue, liver and aorta. They were fixed in formaldehyde and embedded in paraffin. The tissues were sliced (4 μm) and stained using hematoxylin-eosin solution. In the adipose tissue, the visceral fat accumulated, and the size of adipose cells was enlarged in PHT rabbits. The liver of the PHT rabbit was fatty and degenerated. In aorta, increased intimal thickness was observed, suggesting the progression of atherosclerosis in the PHT rabbit. This study suggests the important role of postprandial hypertriglyceridemia in atherosclerosis. By using PHT rabbits, the effects of hypertriglyceridemia on health and diseases could be evaluated precisely

Population structure of Escherichia coli O26 : H11 with recent and repeated stx2 acquisition in multiple lineages2017

A key virulence factor of enterohaemorrhagic Escherichia coli (EHEC) is the bacteriophage-encoded Shiga toxin (Stx). Stxs are classified into two types, Stx1 and Stx2, and Stx2-producing strains are thought to cause more severe infections than strains producing only Stx1. Although O26:H11 is the second most prevalent EHEC following O157:H7, the majority of O26:H11 strains produce Stx1 alone. However, Stx2-producing O26 strains have increasingly been detected worldwide. Through a large-scale genome analysis, we present a global phylogenetic overview and evolutionary timescale for E. coli O26 : H11. The origin of O26 has been estimated to be 415 years ago. Sequence type 21C1 (ST21C1), one of the two sublineages of ST21, the most predominant O26:H11 lineage worldwide, emerged 213years ago from one of the three ST29 sublineages (ST29C2). The other ST21 lineage (ST21C2) emerged 95 years ago from ST21C1. Increases in population size occurred in the late 20th century for all of the O26 lineages, but most remarkably for ST21C2. Analysis of the distribution of stx2-positive strains revealed the recent and repeated acquisition of the stx2 gene in multiple lineages of O26, both in ST21 and ST29. Other major EHEC virulence genes, such as type III secretion system effector genes and plasmid-encoded virulence genes, were well conserved in ST21 compared to ST29. In addition, more antimicrobial-resistance genes have accumulated in the ST21C1 lineage. Although current attention is focused on several highly virulent ST29 clones that have acquired the stx2 gene, there is also a considerable risk that the ST21 lineage could yield highly virulent clones