Hyperlipidemia-induced cholesterol crystal production by endothelial cells promotes atherogenesis.

Endothelial cells (EC) play a key role in atherosclerosis. Although EC are in constant contact with low density lipoproteins (LDL), how EC process LDL and whether this influences atherogenesis, is unclear. Here we show that EC take up and metabolize LDL, and when overburdened with intracellular cholesterol, generate cholesterol crystals (CC). The CC are deposited on the basolateral side, and compromise endothelial function. When hyperlipidemic mice are given a high fat diet, CC appear in aortic sinus within 1 week. Treatment with cAMP-enhancing agents, forskolin/rolipram (F/R), mitigates effects of CC on endothelial function by not only improving barrier function, but also inhibiting CC formation both in vitro and in vivo. A proof of principle study using F/R incorporated into liposomes, designed to target inflamed endothelium, shows reduced atherosclerosis and CC formation in ApoE -/- mice. Our findings highlight an important mechanism by which EC contribute to atherogenesis under hyperlipidemic conditions.

Characteristics of novel di-α-fluoroacrylate derivatives with polyfluoroalkyl aromatic backbone as a binder resin of direct filling materials.

To realize good mechanical properties and water resistance of a dental resin, novel di-α-fluoroacrylates with polyfluoroalkyl aromatic backbone were studied. The monomers were 2,2-bis(4-α-fluoroacryloxy phenyl)propane, 2,2-bis(4-α-fluoroacryloxy phenyl) hexafluoropropane, and 1,3-bis(2-α-fluoroacryloxy-2-hexafluoropropyl)benzene. The copolymers of the monomers and methyl methacrylate (MMA) were excellent in hardness, Izod impact strength, abrasion resistance, and water resistance, and showed similar values of compressive, diametral tensile, tensile, and bending strength compared with copolymers prepared from the corresponding dimethacrylate derivatives and MMA.

Synthesis of dimethacryloxy ethyl-1,1,6,6-tetrahydro-perfluorohexamethylene-1,6-dicarbamate as dental base monomers and the mechanical properties of the copolymers of the monomer and methyl methacrylate.

To recognize good mechanical properties and water-resistance of a dental resin, dimethacryloxyethyl-1,1,6,6-tetrahydro-perfluoro-hexamethylene-1,6-dicarbamate (FDMHD) was newly synthesized. FDMHD initially was a white powder with m.p. 98.5-99.5°C. The copolymers of FDMHD and methyl methacrylate (MMA), FDMHD/MMA copolymers, were prepared to estimate the basic properties for dental resin materials. The compressive strength of FDMHD/MMA copolymers was almost the same compared with those of the copolymers of Bis-GMA or dimethacryloxyethyl-hexamethylene-1,6-carbamate (DMHD) and MMA. The bending, tensile, diametral tensile, impact strength and toughness of FDMHD/MMA copolymers containing 10.4 mol% FDMHD were higher than those of Bis-GMA/MMA copolymer, and the water sorption of FDMHD/MMA copolymers was lower than those of DMHD/MMA copolymers.

Application of liposomes incorporating doxorubicin with sialyl Lewis X to prevent stenosis after rat carotid artery injury.

Restenosis remains a serious complication that can occur after angioplasty. This study investigated the efficiency of an active targeting chemotherapy using liposomes, including doxorubicin, whose surface was decorated with sialyl Lewis X (SLX) (Dox-Lipo-SLX) to prevent stenosis after angioplasty. Its delivery was controlled via the affinity between SLX and E-selectin proteins, which are expressed on vessel walls with injury. In vitro experiments confirmed the accumulation of doxorubicin as a consequence of Dox-Lipo-SLX adhering to E-selectin-positive cells. Significant doxorubicin accumulation was observed on injured vessel walls in rats treated with Dox-Lipo-SLX. In contrast, there was little accumulation using free doxorubicin or a liposome containing doxorubicin (Dox-Lipo), but without SLX. Rats were assigned to one of four groups: Dox-Lipo-SLX, Dox-Lipo, free doxorubicin, or no treatment. Dox-Lipo-SLX, Dox-Lipo, and free doxorubicin, including a dose of 0.08mg/kg doxorubicin, were intravenously administered three times in each group after angioplasty. The residual lumen area of rats in the group treated with Dox-Lipo-SLX was significantly larger than those in all other groups. These results demonstrate that an active targeting drug delivery system utilizing Dox-Lipo-SLX effectively prevents stenosis after angioplasty.

New matrix polymers for photo-activated resin composites using di-alpha-fluoroacrylic acid derivatives.

A novel matrix resin for photo-activated resin composites was developed using alpha-fluoroacrylic acid derivatives. To render resin composites with improved mechanical properties, silica fillers were also used. It was found that the newly developed fluorine-substituted monomer was polymerized quite easily not only by free radical chemical initiators, but also by photoirradiation using free radical photoinitiator system. In particular, the photopolymerization rate of the novel monomer was more than two times faster than that of corresponding methacrylate-based monomer. Composite based on the newly developed matrix resin had higher micro-Vickers hardness and compressive strength values than the methacrylate-based composite, and that it contained only trace residual monomers compared with the methacrylate-based material. The high polymerization conversion of the fluorine-substituted monomer could be attributed to the polar effect or the small steric hindrance of fluorine at the alpha-position.

High-efficacy site-directed drug delivery system using sialyl-Lewis X conjugated liposome.

The aim of this study was to evaluate the new developed sialyl-Lewis X conjugated liposome (sLe XL) as a site-directed delivery system to activated endothelial cells in vivo using a murine experimental autoimmune uveoretinitis (EAU) model. Four types of nanoparticles were prepared using this liposome: fluorescein isothiocyanate (FITC) labeled sLe XL (F-sLe XL) and its vehicle (F-L), sLe XL containing dexamethasone (d-sLe XL) and liposome without sLe X containing dexamethasone (d-L). First, after a bolus injection of F-sLe XL or F-L into EAU mice, sequential tissue accumulation of FITC was examined by confocal laser scanning microscopy. Second, anti-E-selectin antibody, as a blocking antibody, was given intravenously to EAU mice prior to the injection of F-sLe XL in order to investigate the effect of the antibody on inhibition of the accumulation of F-sLe XL. Third, concentration of dexamethasone in several organs after the injection of d-sLe XL (total dexamethasone 2 microg) or free dexamethasone solution (1mg) was measured by radioimmunoassay. Accumulation of FITC was only observed in F-sLe XL treated EAU mice. F-sLe XL accumulated on the activated endothelial cells within 5 min; accumulation then was inhibited using anti-E-selectin antibody. The FITC color was dispersed sequentially to the entire retina. d-sLe XL showed selective targeting to the inflamed eye, where an approximately two-fold higher dexamethasone concentration was achieved compared with 1mg free dexamethasone. sLe XL can be a highly efficacious site-directed system in vivo. Using sLe XL as a vehicle for drug delivery, substantial pharmacologic effects with minimum side effects in inflammatory diseases should be achieved.

Accumulation of liposome with Sialyl Lewis X to inflammation and tumor region: application to in vivo bio-imaging.

We prepared the liposome binding Sialyl Lewis X (SLX) on the surface in order to specifically and efficiently deliver substances (fluorescent materials, chemical substances, proteins, genes, etc.) to inflammation or tumor regions. The liposome with SLX (SLX-Lipo-Cy5.5), in which fluorescent substance Cy5.5 was included, was administered intravenously to arthritis or Ehrlich Ascites Tumor (EAT) bearing mouse, and the accumulation of liposome was observed using two types of in vivo fluorescent imaging equipment. The result was that the accumulation of SLX-Lipo-Cy5.5 to inflammation or tumor regions was significantly higher than the control liposome without sugar chain (Lipo-Cy5.5) at 24 and 48 h after administration. In addition, it was confirmed that this accumulation showed a shift of liposome from blood vessels to the surrounding tissues. Thus, it was proven that this liposome is useful not only as an in vivo bio-imaging reagent but also as a drug delivery system (DDS).

Eye-concentrated distribution of dexamethasone carried by sugar-chain modified liposome in experimental autoimmune uveoretinitis mice.

Corticosteroid is generally accepted as a standard therapeutic agent for active inflammatory (and) autoimmune eye diseases. In an attempt to develop a system to deliver corticosteroid most efficiently to the target eye, a sialyl-Lewis X (sLe(x))-conjugated liposome was adopted as a candidate for a carrier of dexamethasone (Dexa) and tissue distribution of intravenous Dexa with the modified liposome as well as Dexa alone as control was studied in normal and experimental autoimmune uveoretinitis (EAU) mice. Intravenous Dexa (1 mg) was widely distributed in all the tissues (eye, brain, heart, lung, liver, kidney, spleen and intestine) examined in similar manner in both mice and Dexa concentration was lowest in the eye except the brain. The tissue concentrations of Dexa in EAU group were all significantly lower than those in the corresponding tissues in normal group. Intravenous Dexa (2 microg) in the modified liposome was almost concentrated to the eye in EAU mice, reaching 13.84 ng/mg tissue in contrast to 2.34 ng/mg tissue in Dexa (1 mg) alone administered EAU mice. In normal mice, Dexa was undetectable in any tissues examined and thus the effect of the modified liposome was not observed. The result supported the potentiality of sLe(x)-conjugated liposome for target-delivering of corticosteroid to inflamed eye.