E-selectin is a major adhesion molecule expressed by endothelial cells (ECs), which are exposed to shear stress and neighboring smooth muscle cells (SMCs). We investigated the mechanisms underlying the modulation of EC E-selectin expression by SMCs and shear stress. SMC coculture induced rapid and sustained increases in expression of E-selectin and phosphorylation of interleukin-1 (IL-1) receptor-associated kinase and glycopro-tein-130, as well as the downstream mitogen-activated protein kinases (MAPKs) and Akt. By using specific in-hibitors, dominant-negative mutants, and small interfering RNA, we demonstrated that activations of c-Jun-NH 2-terminal kinase (JNK) and p38 of the MAPK pathways are critical for the cocul-ture-induced E-selectin expression. Gel shifting and chromatin immunoprecipita-tion assays showed that SMC coculture increased the nuclear factor-B (NF-B)-promoter binding activity in ECs; inhibition of NF-B activation by p65-anti-sense, lactacystin, and N-acetyl-cysteine blocked the coculture-induced E-selectin promoter activity. Protein arrays and blocking assays using neutralizing anti-bodies demonstrated that IL-1 and IL-6 produced by EC/SMC cocultures are major contributors to the coculture induction of EC signaling and E-selectin expression. Preshearing of ECs at 12 dynes/cm 2 inhibited the coculture-induced EC signaling and E-selectin expression. Our findings have elucidated the molecular mechanisms underlying the SMC induction of EC E-selectin expression and the shear stress protection against this SMC induction. (Blood. 2007; Introduction During the development of atherosclerotic lesions, vascular smooth muscle cells (SMCs) change from their physiologic contractile phenotype to the pathophysiologic synthetic phenotype and migrate into the intima, where they release proinflam-matory cytokines and interact with vascular endothelial cells (ECs) to regulate their gene expression and function, including the modulation of leukocyte recruitment. 1-3 ECs are constantly subjected to blood flow-induced shear stress, which can modulate leukocyte-EC interaction and the subsequent leukocyte extravasation into inflamed tissue, mainly by modulating EC surface expression of adhesion molecules. 3,4 E-selectin is a major EC adhesion molecule that regulates binding and extravasation of leukocytes from the bloodstream to sites of inflammation. The effects of cytokines and shear stress on EC E-selectin expression have been extensively studied. The E-selectin gene is rapidly expressed by ECs in response to proinflammatory cytokines, and it is more responsive to disturbed and oscillatory flows 5,6 than to laminar shear stress. 7 Most studies on effects of shear stress on EC gene expression have been performed on EC monolayers, which may not reflect the in vivo environment of ECs, which exist in close proximity to SMCs. By using our newly developed EC/SMC coculture flow system 8 in which ECs and SMCs are grown on opposite sides of a porous membrane, we demonstrated that coculture with SMCs induced E-selectin expr...

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Water-soluble chitooligosaccharides have been reported to have specific biological activities. In this study, the chitosan samples with different degree of acetylation were used separately to prepare chitooligosaccharide (COS) and highly deacetylated chitooligosaccharide (HDCOS) through the nitrous acid depolymerization. Rather than using the conventional fractionation schemes commonly employed, such as dialysis and ultrafiltration which require a large amount of deionized water as well as a fair long dwell time, an unique fractionation scheme is explored to recover and desalt these nitrous-acid depolymerized chitosan with different molecular weights. This fractionation scheme is based on the differential solubility variation of depolymerized products within the aqueous solutions that contain various ratios of methanol. It was noted that chitosan with different molecular weight can be successfully recovered and fractionated with methanol added sequentially up to a volume of four times of original depolmerized product. In addition, chemical characterization of the fractionated water-soluble COS and HDCOS by 1H NMR spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) indicated that the chitosan depolymerization reaction is greatly influenced by the degree of acetylation of the parental chitosan reactant. Moreover, the modified whole blood clotting time assay and the platelet coagulation test suggested that the 1:2 fractionated water-soluble COS and HDCOS obtained are much less procoagulant than their parental chitosan compound and can be of use in biomedical applications in which blood coagulation is not desired.

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Cyanoacrylates have known for their ability to polymerize rapidly in the presence of traces of weakly basic moieties such as water. The tissue adhesive, Histoacryl(R) (N-butyl 2-cyanoacrylate), has been reported to control bleeding through endoscopic sclerotherapy. But the commercially available Histoacryl(R) is expensive, and it has the problem like other cyanoacrylates that the glue tends to flow/run away from the point of application, which is inherent to the low viscosity, making precise application difficult. In this study, ethyl cyanoacrylate (ECA), the main constituent of "super glue," was employed instead of Histoacryl(R) due to its lower cost. The aim of the research is to modify the compositions of ECA regimen and evaluate its feasibility for sclerosant application through both in vitro flow circuit model and in vivo animal tests. It was noted that the difference in the relative hardening rate between the in vitro Hepes-Tyrodes buffer flowing model and the in vivo rat model for the ECA and Histoacryl(R) was related to the existence of the blood protein, such as albumin, in the physiological milieu. It was also noticed that the ECA setting rate was greatly increased either in Hepes-Tyrodes buffer or in blood (to a comparable rate as Histoacryl(R) in vivo) by adding a few doses of caffeine, which acts as a polymerization initiator. This would lead to far better injection precision during sclerotherapy. Furthermore, in vivo histological examination for the occluded lumen of the rat's inferior vena cava and a clinical piglet portal vein occlusion experiment have suggested this new sclerosant regimen, caffeine/ECA, is of great promise in endoscopic sclerotherapy.