Antibodies to oxidized low-density lipoprotein in patients following coronary artery revascularization

Relationship between oxidized LDL antibodies and different stages of esophageal carcinoma

BACKGROUND

The aim of the study was to evaluate the association of antibodies against oxidized low-density lipoproteins (oxLDL-Ab) with esophageal carcinogenic progression.

METHODS

All 40- to 69-year-old residents from Feicheng were screened for esophageal lesions by endoscopic staining with 1.2% iodine solution combined with pathological evaluations. In this study there were 33 controls with normal esophageal squamous epithelium cells, 37 patients with basal cell hyperplasia, 47 with esophageal squamous cell dysplasia, and 43 with esophageal squamous cell carcinoma (ESCC). OxLDL-Ab was determined by ELISA. Total cholesterol (TC), high-density lipoproteins (HDL), triglycerides, serum albumin and blood pressure were co-estimated. Analysis of covariance (ANCOVA) was used when comparing oxLDL-Ab among the four groups to control the influence of covariates. Cumulative logistic model was applied to study the influencing factors for the multistage development of esophageal carcinoma.

RESULTS

The level of oxLDL-Ab decreased gradually along with the different stages of esophageal carcinogenic progression, with the ESCC group being the lowest after controlling for possible covariates. Cumulative logistic model showed that oxLDL-Ab had a negative correlation with the development of esophageal carcinoma. LDL, HDL, and TC were also decreased in patients with ESCC.

CONCLUSIONS

Antibodies against oxLDL were decreased in patients with esophageal carcinoma. Although the unambiguous role of oxLDL-Ab needs further studies to elucidate, the results may give us some insight in the research of etiological factors for esophagael cancer in the future.

The human IgM antibody SAM-6 induces tumor-specific apoptosis with oxidized low-density lipoprotein

Lipids are essential for normal and malignant cells during growth and differentiation. The turnover is strictly regulated because an uncontrolled uptake and accumulation is cytotoxic and can lead to lipoapoptosis: lipoptosis. The human monoclonal antibody SAM-6 binds to a cell surface receptor on malignant cells and to oxidized low-density lipoprotein (LDL). SAM-6 induces an excess of intracellular lipids, by overfeeding malignant cells with oxidized LDL, via a receptor-mediated endocytosis. The treated cells overaccumulate depots of cholesteryl esters and triglycerides. This lipid overaccumulation is tumor specific; nonmalignant cells neither bind the antibody nor harvest lipids after incubation. Because for both forms of apoptosis, the death domain dependent ("extrinsic") and independent ("intrinsic"), the activation of proteases is crucial, we also investigated this pathway in more detail. It was found that shortly after internalization of antibody/oxidized LDL/receptor complex and formation of lipid depots, cytochrome c is released by mitochondria. Followed by this, initiator caspase-8 and caspase-9 and effector caspase-3 and caspase-6 are activated. The mechanism of mitochondrial trigger (e.g., by free fatty acids) is under investigation. However, the present data indicate that the SAM-6 antibody induces an intrinsic-like form of apoptosis by overfeeding malignant cells with lipoproteins.