Junji Kimura

Inverse relationship between circulating oxidized low density lipoprotein (oxLDL) and anti-oxLDL antibody levels in healthy subjects

Oxidized low density lipoprotein (oxLDL) has been implicated in the pathogenesis of atherosclerosis. Recent studies have shown that immunization of animals with oxLDL results in suppression of atherogenesis. Antibody against oxLDL (oxLDL Ab) is detectable in human sera, although its biological significance is not well established. We examined the relationship between oxLDL Ab titer and circulating oxLDL level in 130 healthy Japanese subjects. OxLDL was measured as apolipoprotein (apo) B-containing lipoproteins carrying oxidized phosphatidylcholines by a sensitive ELISA. IgG class oxLDL Ab titer was measured by ELISA. Plasma oxLDL concentration was very low and it corresponded on average to one to two out of 1000 apoB-containing lipoproteins in plasma. Plasma oxLDL correlated positively with LDL cholesterol and inversely with oxLDL Ab titer. These associations remained significant and independent in multiple regression analysis including age, gender, smoking, and high-density lipoprotein cholesterol. These data indicate that healthy subjects have a very low concentration of oxLDL in the circulation, and that oxLDL Ab titer is in an inverse relationship with plasma oxLDL concentration in this population. Although these results suggest that oxLDL Ab may play a role in maintaining the low level of plasma oxLDL, its role in atherogenesis awaits further studies.

Preferential binding of polyethylene glycol-coated liposomes containing a novel cationic lipid, TRX-20, to human subendthelial cells via chondroitin sulfate

AbstractPurpose. To design novel cationic liposomes, polyethylene glycol (PEG)-coated cationic liposomes containing a newly synthesized cationic lipid, 3,5-dipentadecyloxybenzamidine hydrochloride (TRX-20) were formulated and their cellular binding and uptake investigated in vitro in the following cells: human subendothelial cells (aortic smooth muscle cells and mesangial cells) and human endothelial cells. Methods. Three different PEG-coated cationic liposomes were prepared by the extrusion method, and their mean particle size and zeta potential were determined. Rhodamine-labeled PEG-coated cationic liposomes were incubated with smooth muscle cells, mesangial cells, and endothelial cells at 37°C for 24 h. The amounts of cellular binding and uptake of liposomes were estimated by measuring the cell-associated fluorescence intensity of rhodamine. To investigate the binding property of the liposomes, the changes of the binding to the cells pretreated by various kinds of glycosaminoglycan lyases were examined. Fluorescence microscopy is used to seek localization of liposomes in the cells. Results. The cellular binding and uptake of PEG-coated cationic liposomes to smooth muscle cells was depended strongly on the chemical species of cationic lipids in these liposomes. Smooth muscle cells bound higher amount of PEG-coated TRX-20 liposomes than other cationic liposomes containing N-(1-(2,3-dioleoyloxy) propyl)-N, N, N-trimethylammonium salts or N-(α-(trimethylammonio)acetyl)-D-glutamate chloride. Despite of the higher affinity of PEG-coated TRX-20 liposomes for subendothelial cells, their binding to endothelial cells was very small. The binding to subendothelial cells was inhibited when cells were pretreated by certain kinds of chondroitinase, but not by heparitinase. These results suggest that PEG-coated TRX-20 liposomes have strong and selective binding property to subendothelial cells by interacting with certain kinds of chondroitin sulfate proteoglycans (not with heparan sulfate proteoglycans) on the cell surface and in the extracellular matrix of the cells. This binding feature was different from that reported for other cationic liposomes. Conclusions. PEG-coated TRX-20 liposomes can strongly and selectively bind to subendothelial cells via certain kinds of chondroitin sulfate proteoglycans and would have an advantage to use as a specific drug delivery system.

Vascular responses to a biodegradable polymer (polylactic acid) based Biolimus A9-eluting stent in porcine models

AIMS The time-dependent changes in endothelial and healing properties of coronary arteries implanted with a biodegradable polymer-based biolimus A9-eluting stent (BioPol-BES) have not been investigated. We evaluated the short-term and the long-term in vivo response of BioPol-BES, as compared to a permanent polymer-based sirolimus-eluting stent (PermPol-SES), and a bare metal stent (BMS). METHODS AND RESULTS Overlapping stents were placed in 33 swine (n=11 for BES, SES, and BMS, respectively) for two and four weeks and single stents in 30 miniature pigs (n=18 for BES, n=9 for SES, n=3 for BMS) for three, nine and 15-month evaluations. The vessel patency, arterial healing and endothelialisation were assessed by angiography, histopathology and scanning electron microscopy. At four weeks, the endothelialisation at overlapping stent regions was greater with BioPol-BES (87.8±3.7%) and BMSs (98.0±0.4%) than with PermPol-SES (66.4±3.2%). The inflammation score in vessels implanted with single BioPol-BES increased slightly from three to 15 months (0.00±0.00 to 0.28±0.14), while this increase was more pronounced with PermPol-SES (0.11±0.07 to 1.56±0.68). Compared to BMS moderate lymphocyte infiltration was seen with BioPol-BES, and marked granulomatous formation with PermPol-SES. CONCLUSIONS The level of endothelial coverage in BioPol-BES was comparable to BMS at four weeks, with no significant increase of inflammatory reaction up to 15 months.

Prednisolone phosphate-containing TRX-20 liposomes inhibit cytokine and chemokine production in human fibroblast-like synovial cells: a novel approach to rheumatoid arthritis therapy.

To evaluate the potential of using prednisolone phosphate (PSLP)‐containing 3,5‐dipentadecyloxybenzamidine hydrochloride (TRX‐20) liposomes to treat rheumatoid arthritis (RA), we examined their ability to bind human fibroblast‐like synovial (HFLS) cells and their effects in these cells. To test for binding, Lissamine rhodamine B‐1, 2‐dihexadecanoyl‐sn‐glycero‐3‐phosphoethanolamine (rhodamine)‐labelled PSLP‐containing TRX‐20 liposomes were added to HFLS cells, and the fluorescence intensity of the rhodamine bound to the cells was evaluated. Rhodamine‐labelled PSLP‐containing liposomes without TRX‐20 were used as a negative control. To evaluate the uptake of liposomes by the HFLS cells, we used TRX‐20 liposomes containing 8‐hydroxypyrene‐1,3,6‐trisulfonic acid (HPTS) and p‐xylene‐bis‐pyridinium bromide (DPX), and observed the cells by fluorescence microscopy. The effects of the PSLP in TRX‐20 liposomes on HFLS cells were assessed by the inhibition of the production of two inflammatory cytokines (interleukin 6 and granulocyte macrophage colony‐stimulating factor) and one inflammatory chemokine (interleukin 8). The interaction of the PSLP‐containing TRX‐20 liposomes with HFLS cells was approximately 40 times greater than that of PSLP‐containing liposomes without TRX‐20. PSLP‐containing TRX‐20 liposomes bound to HFLS cells primarily via chondroitin sulfate. TRX‐20 liposomes taken up by the cell were localized to acidic compartments. Furthermore, the PSLP‐containing TRX‐20 liposomes inhibited the production of the inflammatory cytokines and the chemokine more effectively than did the PSLP‐containing liposomes without TRX‐20. These results indicate that PSLP‐containing TRX‐20 liposomes show promise as a novel drug delivery system that could enhance the clinical use of glucocorticoids for treating RA.