Associations of Tissue and Soluble LOX-1 with Human Abdominal Aortic Aneurysm

Background Indication for prophylactic surgical abdominal aortic aneurysm (AAA) repair depends on the maximal aortic diameter. The lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is the major receptor for uptake of oxidized low-density lipoprotein cholesterol and is implicated in atherosclerosis. A soluble form of LOX-1 (sLOX-1) has been discussed as a novel biomarker in coronary artery disease and stroke. Herein, we assessed the regulation of aortic LOX-1 as well as the diagnostic and risk stratification potential of sLOX-1 in patients with AAA. Methods and Results Serum sLOX-1 was assessed in a case-control study in AAA (n=104) and peripheral artery disease (n=104). sLOX-1 was not statistically different between AAA and peripheral artery disease but was higher in AAA (β=1.28, P=0.04) after adjusting for age, atherosclerosis, type 2 diabetes, prescription of statins, β-blockers, ACE inhibitors, and therapeutic anticoagulation. sLOX-1 was not associated with the aortic diameter, AAA volume, or the thickness of the intraluminal thrombus. Aortic LOX-1 mRNA expression tended to be higher in AAA when compared with disease, and expression was positively associated with cleaved caspase-3, smooth muscle actin, collagen, and macrophage content. Conclusions In AAA, sLOX-1 was differently affected by age, cardiometabolic diseases, and corresponding medical therapies. Comparison with nonatherosclerotic disease would be beneficial to further elucidate the diagnostic potential of sLOX-1, although it was not useful for risk stratification. Aneurysmal LOX-1 mRNA expression was increased and positively associated with smooth muscle cells and collagen content, suggesting that LOX-1 is eventually not deleterious in human AAA and could counteract AAA rupture.

Circulatory soluble LOX-1 is a novel predictor for coronary artery disease patients

BACKGROUND

This study investigated the biomarker effect of soluble lectin-like oxidised low-density lipoprotein (sLOX-1) levels for the evaluation of stable and unstable coronary heart disease, correlating it with aging.

METHODS

This case-control study was conducted at the Cardiology Department of Xiangya Hospital between June 2015 and September 2018. Stable coronary artery disease (CAD) patients were confirmed by an invasive coronary angiogram, and American College of Cardiology as well as European Cardiology Society clinical protocols were used for the diagnosis of unstable CAD subjects. Plasma sLOX-1 levels were determined from 226 stable CAD patients, 138 unstable CAD subjects and 75 healthy participants by enzyme-linked immunosorbent assay.

RESULTS

Plasma sLOX-1 expressions were significantly elevated in stable CAD patients (4.5-fold) and unstable CAD patients (5.8-fold) above that of volunteer healthy participants. Moreover, between the stable and unstable patient groups, sLOX-1 concentrations were also statistically significantly different (p < 0.001). Levels of plasma sLOX-1 in the healthy female (30-60 years), and stable and unstable CAD female subjects (61-84 years) were markedly elevated compared with healthy male (30-60 years), as well as stable and unstable CAD male patients (61-84 years) (p < 0.001). Besides, in the female unstable CAD (61-84 years) subjects, circulatory sLOX-1 expressions were much higher than in the younger female unstable CAD (30-60 years) patients (p < 0.001). The stable CAD patients were clearly differentiated from healthy subjects with a high sensitivity of the area under the curve (AUC = 0.895). Unstable CAD patients and healthy subjects were also markedly different with a high sensitivity, as shown by AUC (0.902). Stable and unstable CAD subjects were differentiated with an AUC of 0.867.

CONCLUSIONS

Elevated plasma sLOX-1 levels could be regarded as a novel biomarker for detecting CAD patients and there was a significant association with gender and aging.