BACKGROUND AND OBJECTIVE Periodontal disease is a chronic inflammatory disease caused by bacterial infection that can lead to tooth loss. Gingival crevicular fluid can be collected easily and noninvasively. We previously discovered the presence of apolipoprotein B (apoB), the main constituent of low-density lipoprotein, and oxidized low-density lipoprotein (oxLDL) in the gingival crevicular fluid of healthy subjects. In this study, we investigated whether periodontal conditions affect the levels of apoB and oxLDL in gingival crevicular fluid. MATERIAL AND METHODS The study population comprised 11 patients with chronic periodontitis. A pair of gingival crevicular fluid samples was collected from each patient at a healthy site and at a site with periodontitis (baseline samples). Thereafter, gingival crevicular fluid samples were collected from the same patients again at 4 and 8 wk after scaling and root planing (SRP). The levels of apoB, oxLDL, protein and cytokines in gingival crevicular fluid, in addition to gingival crevicular fluid volume, were measured. RESULTS At baseline, the levels of apoB and oxLDL in gingival crevicular fluid were higher at the sites with periodontitis than at the healthy sites. The levels of apoB and oxLDL at periodontal sites decreased after SRP. The level of oxLDL in gingival crevicular fluid correlated well with the probing pocket depth. The oxLDL : apoB ratio in gingival crevicular fluid was significantly higher than that in plasma. CONCLUSIONS The levels of apoB and oxLDL in gingival crevicular fluid change according to the periodontal tissue conditions.

Ovarian cancer is the fifth most common cancer among women and approximately 200,000 women are diagnosed as ovarian cancer every year in the world (Parkin et al., 2005). Platinum-containing chemotherapeutic agents such as cisplatin (cisdiamminedichloroplatinum II) and carboplatin have been most frequently used for the treatment of ovarian cancer. These platinum compounds specifically react with guanine residues in DNA to form interstrand and intrastrand cross-links in DNA, known as DNAadducts. This interferes with mitosis of cancer cells and causes cell death. However, ovarian cancer cells can become resistant to cisplatin and the majority of patients develop cisplatinresistant disease (Giaccone 2000; Hennessy et al., 2009; Kartalou & Essigmann 2001), and as a result, most ovarian cancers relapse. Paclitaxel (taxol) and two analogues of camptothecin, irinotecan and topotecan, are the drugs most commonly administered to platinum-resistant ovarian cancer patients. Paclitaxel (taxol) binds to -tubulin and stabilizes microtubule structure, which causes a G2/M block in the cancer cell cycle. Irinotecan, also known as CPT-11 (7-ethyl-10-[4-(1-piperidino)-1-piperidino]-carbonyloxy camptothecin) and topotecan (10-hydroxy-9-dimethylaminomethyl-(S)-camptothecin) inhibit topoisomerase I by resealing DNA breaks, which results in the inhibition of cancer cell growth (Bookman et al., 1998; Swisher et al., 1997). However, the survival rate for relapsed patients is low; Thus, there is an urgent need for more effective chemotherapeutic approaches for ovarian cancer treatment. We have previously reported that some ovarian cancer cell lines are remarkably sensitive to vitamin K2 (Shibayama-Imazu et al, 2003, 2006, 2008). In this review, strategies for developing chemotherapeutic agents for ovarian cancer are described and vitamin K2 is proposed as a promising chemotherapeutic agent for ovarian cancer.

BACKGROUND AND OBJECTIVE:Oxidative modification of low-density lipoprotein (LDL) occurs in various diseased tissues and sites of local inflammation. For example, an increased plasma oxidized low-density lipoprotein (OxLDL) level is a well-known risk marker for cardiovascular diseases. Gingival crevicular fluid, the exudate from gingival tissues into the sulci, can be easily collected in a non-invasive manner. However, the possible presence of OxLDL in gingival crevicular fluid has not been studied. In this study, we established a procedure to measure OxLDL in human gingival crevicular fluid.MATERIAL AND METHODS:Human gingival crevicular fluid was sampled with paper points or paper strips. The gingival crevicular fluid samples from healthy gingival sulci (pocket depth < 4 mm, n = 14) were subjected to western blot and/or sandwich ELISA. The amounts of OxLDL and LDL were measured by sandwich ELISA using an anti-oxidized phosphatidylcholine monoclonal antibody and two anti-apolipoprotein B antibodies. Venous blood samples were analyzed biochemically.RESULTS:We tested two methods of gingival crevicular fluid collection, namely paper points and paper strips. Gingival crevicular fluid could be collected very safely with paper points and they showed good recovery of LDL and OxLDL throughout the analysis. Apolipoprotein B, the major protein component in LDL, was detected in gingival crevicular fluid by western blot, and OxLDL was found to be present in gingival crevicular fluid by ELISA. The OxLDL/LDL ratio in gingival crevicular fluid was 17.0 times higher than that in plasma.CONCLUSION:This is the first report to show the presence of apolipoprotein B and apolipoprotein B- oxidized phosphatidylcholine complex, which correspond to LDL and OxLDL, respectively, in gingival crevicular fluid.

BACKGROUND AND OBJECTIVE:Recent epidemiological studies have shown a correlation between periodontitis and hyperlipidemia. We have found high levels of oxidized low-density lipoprotein (OxLDL) in the gingival crevicular fluid of dental patients. In the present study, we tried to examine the possible role of OxLDL in periodontal inflammation in vitro.MATERIAL AND METHODS:Cells of the human gingival epithelial cell line Ca9-22 were cultured in media containing OxLDL, and the amounts of interleukin-8 (IL-8) and prostaglandin E(2) (PGE(2)) produced were measured using ELISAs.RESULTS:Production of IL-8 by Ca9-22 cells was significantly increased when the cells were treated with OxLDL, but not with native LDL or acetylated LDL. Production of PGE(2) by Ca9-22 cells was enhanced by co-incubation with OxLDL and interleukin-1 beta (IL-1 beta). Scavenger receptor inhibitors, fucoidan and dextran sulfate, inhibited the OxLDL-induced IL-8 and PGE(2) production in the presence of IL-1 beta. The p(38) MAPK inhibitors SB203580 and SB202190 and the ERK inhibitor PD98059 inhibited the OxLDL-induced IL-8 production. Among oxidized lipids and chemically modified LDL, 7-ketocholesterol enhanced IL-8 production.CONCLUSION:This is the first report to show that OxLDL enhances IL-8 production in epithelial cells.

Oxidized low-density lipoprotein (OxLDL) has been shown to exist in human circulating plasma. Several groups including ours have developed methods for immunologically measuring OxLDL, which have been applied to several clinical, both cross-sectional and prospective, studies. These data clearly show that OxLDL levels correlate well with the severity of cardiovascular diseases. In particular, recent observations suggest that plasma OxLDL levels could be a useful marker for predicting future cardiovascular events; however, substantial differences exist among the different methods of OxLDL measurement. To evaluate the clinical data on circulating OxLDL, a proper understanding of the similarity, differences, and limitation of the methods is needed. This paper summarizes the characteristics of the methods used and recent clinical findings.

Several interpretations have been made regarding the specificity of antiphospholipid antibodies and antibodies against oxidized low-density lipoprotein (oxLDL), but these are still controversial. In the present study, we delineated specificity of these two types of antibodies and analyzed their regulatory effect on oxLDL and/or β 2-glycoprotein I (β2GPI) binding to macrophages. Scavenger receptor-mediated binding of oxLDL (or its β2GPI complexes) to macrophages was observed and the binding was partly prevented by β 2GPI. The IgG monoclonal anti-β2GPI antibody (WB-CAL-1), which was derived from NZW × BXSB F1 mouse (a model of antiphospholipid syndrome), significantly increased the oxLDL/β2GPI binding to macrophages. In contrast, IgM anti-oxLDL natural antibody, EO6 (derived from apoe -/- mouse), prevented the binding. Different antigenic specificity of these antibodies to oxLDL and its β2GPI complexes was also confirmed in TLC—ligand blot and ELISA. Thus, IgG anti-β2 GPI autoantibodies contribute to lipid metabolism (housekeeping of oxLDL by macrophages) whereas IgM natural anti-oxLDL antibodies may protect against atherogenesis. In addition, in vitro data suggest that relatively high dose of intravenous immunoglobulin preparations (mainly contain IgG anti-oxLDL antibodies) might also prevent atherogenesis by inhibiting the oxLDL binding to macrophages. Lupus (2007) 16, 929—938.

Objective: Using human cartilage samples and cultured chondrocytes, to assess the possible involvement of oxidized low-density lipoprotein (ox-LDL) and lectin-like ox-LDL receptor-1 (LOX-1) in pathogenesis and progression of osteoarthritis (OA).Methods: Thirty-two cartilage samples were obtained from 16 patients with knee OA, and 12 Control samples from six with femoral neck fracture. LOX-1 mRNA expressions in 12 OA and six Control samples were analyzed by reverse transcription-polymerase chain reaction (RTPCR). Immunohistochemistry for ox-LDL and LOX-1 was performed in all samples. The histological CA grade was assessed with the modified Mankin score. The relative percentage of the ox-LDL and LOX-1 immunopositive chondrocytes was calculated in all samples. The effects of ox-LDL on cell viability in cultured human chondrocytes were 5 investigated by the 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay and on proteoglycan synthesis by monitoring [S-35] sulfate incorporation.Results: There was a statistically significant difference between mean LOX-1/GAPDH (LOX-1/human glyceralclehyde-3-phosphate dehydrogenase) ratio of OA samples and that of Control samples (40.6% +/- 10.3 and 11.9% +/- 2.8, respectively, P < 0.0001). The mean percentage of ox-LDL-positive cells was 23.0 +/- 15.7% in OA and 4.3 +/- 3.7% in Control cells (P = 0.0002). The mean percentage of LOX-1-positive cells was 51.7 +/- 29.5% in OA and 10.0 +/- 8.1% in Control cells (P < 0.0001). Both the ox-LDL immunoreactivity and the LOX-1 immunoreactivity were significantly correlated with the modified Mankin scores (R-2 = 0.67 and 0.48, respectively; P < 0.0001 for each). ox-LDL significantly reduced the human chondrocyte viability and proteoglycan synthesis, and pretreatment with anti-human LOX-1 monoclonal antibody reversed these effects.Conclusion: The ox-LDL/LOX-1 system may be involved in human OA. (C) 2006 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Oxidized low-density lipoprotein (OxLDL) is thought to be involved in the early development of atherosclerosis through foam cell formation. It has been more than 20 years since the importance of OxLDL in atherogenesis was pointed out. During the last decade a couple of groups including ours have successfully detected OxLDL present in human circulating blood, and showed close relationship between the OxLDL levels and cardiovascular diseases. However, the actual nature of OxLDL found in vivo remained obscure until recently. In this article, a basis of the so-called “OxLDL hypothesis” on atherosclerosis will be summarized briefly, and the important issues to be solved in the near future are also discussed.

It has been suggested that oxidative stress plays a pathogenic role in idiopathic interstitial pneumonias. Macrophage- or neutrophil-derived oxidants seem to be important sources of oxidative stress in this group of inflammatory disorders. Recent experimental studies have revealed that oxidative injury during inflammation or apoptosis can change phosphatidylcholine of cell membrane into its oxidized form, which serves as a ligand for macrophage scavenger receptor CD36. Recently, we developed a monoclonal antibody against oxidized phosphatidylcholine. Using this novel antibody, we performed an immunohistochemical investigation to clarify the localization of oxidized phosphatidylcholine in lung tissues of idiopathic interstitial pneumonias and a relationship between oxidized phosphatidylcholine localization and CD36 expression. Lung specimens obtained from patients with desquamative (n = 8) or usual interstitial pneumonia (n = 15) were studied. Thirteen normal lung tissues were also examined as controls. Antibodies against oxidized phosphatidylcholine, CD36, epithelial cells, macrophages, and neutrophils were used as primary antibodies. The positive cell number was counted by computer-aided morphometry. While there were no oxidized phosphatidylcholine-positive cells in normal lungs, lungs of desquamative or usual interstitial pneumonia contained large numbers of oxidized phosphatidylcholine-positive cells in the alveolar spaces. Double-staining analysis revealed that most oxidized phosphatidylcholine-positive cells were macrophages. The oxidized phosphatidylcholine-positive cells were increased in association with the increase in the densities of macrophages (Rs = 0.87, p < 0.0001) and neutrophils (Rs = 0.89, p < 0.0001). Accumulated macrophages also showed distinct CD36 expression. These findings suggest that oxidative stress and the related product, oxidized phosphatidylcholine, play an important role in the pathophysiology of idiopathic interstitial pneumonias.

We investigated the association among plasma levels of oxidatively modified low-density lipoprotein (Ox-LDL), high-density lipoprotein-cholesterol (HDL-C), and the prevalence of coronary artery disease (CAD) in a case-control study. Cases (n = 183, male [M]/female [F]:138/45, age: 64.9 ± 10.6 years) were defined as patients with angiographically proven coronary atherosclerosis (≥50% stenosis) and controls were subjects with normal coronary arteries (n = 74, M/F:36/38, age: 57.6 ± 14.4 years). Plasma Ox-LDL levels were measured by a sensitive detection method using the monoclonal antibody DLH3. In women, both Ox-LDL and lipid variables were similar between cases and controls. In men, cases had significantly lower (P < .05) levels of HDL-C (39.1 ± 10.3 v 42.8 ± 10.9 mg/dL) and apolipoprotein (apo) A-I than controls, while the difference in Ox-LDL between cases and controls was not significant (1.05 ± 0.79 and 0.83 ± 0.65 ng/10 μg LDL protein, respectively). However, HDL-C levels interacted with the association between Ox-LDL levels and CAD in males: increased Ox-LDL levels were significantly associated with CAD after controlling for age when HDL-C levels were high, but were not associated with CAD when HDL-C levels were low, as assessed by a multiple logistic regression analysis. In addition, the combination of HDL-C and Ox-LDL levels was a better indicator for CAD in males than HDL-C levels alone (−2 log likelihood, 24.1 v 19.4) after controlling for age and conventional risk factors of CAD, while Ox-LDL levels were not significantly associated with CAD. HDL-C levels interact with the association between plasma Ox-LDL levels and CAD in men, and increased Ox-LDL levels are an indicator of CAD in male subjects with high HDL-C levels.