High Levels of Soluble Lectin-Like Oxidized Low-Density Lipoprotein Receptor-1 in Acute Stroke: An Age- and Sex-Matched Cross-Sectional Study

LOX-1 in Cardiovascular Disease: A Comprehensive Molecular and Clinical Review

LOX-1, ORL-1, or lectin-like oxidized low-density lipoprotein receptor 1 is a transmembrane glycoprotein that binds and internalizes ox-LDL in foam cells. LOX-1 is the main receptor for oxidized low-density lipoproteins (ox-LDL). The LDL comes from food intake and circulates through the bloodstream. LOX-1 belongs to scavenger receptors (SR), which are associated with various cardiovascular diseases. The most important and severe of these is the formation of atherosclerotic plaques in the intimal layer of the endothelium. These plaques can evolve into complicated thrombi with the participation of fibroblasts, activated platelets, apoptotic muscle cells, and macrophages transformed into foam cells. This process causes changes in vascular endothelial homeostasis, leading to partial or total obstruction in the lumen of blood vessels. This obstruction can result in oxygen deprivation to the heart. Recently, LOX-1 has been involved in other pathologies, such as obesity and diabetes mellitus. However, the development of atherosclerosis has been the most relevant due to its relationship with cerebrovascular accidents and heart attacks. In this review, we will summarize findings related to the physiologic and pathophysiological processes of LOX-1 to support the detection, diagnosis, and prevention of those diseases.

Serum Soluble Lectin-like Oxidized Low-Density Lipoprotein Receptor-1 (sLOX-1) Is Associated with Atherosclerosis Severity in Coronary Artery Disease

Risk-factor-based scoring systems for atherosclerotic coronary artery disease (CAD) remain concerningly inaccurate at the level of the individual and would benefit from the addition of biomarkers that correlate with atherosclerosis burden directly. We hypothesized that serum soluble lectin-like oxidized low-density lipoprotein receptor-1 (sLOX-1) would be independently associated with CAD and investigated this in the BioHEART study using 968 participants with CT coronary angiograms, which were scored for disease burden in the form of coronary artery calcium scores (CACS), Gensini scores, and a semi-quantitative soft-plaque score (SPS). Serum sLOX-1 was assessed by ELISA and was incorporated into regression models for disease severity and incidence. We demonstrate that sLOX-1 is associated with an improvement in the prediction of CAD severity when scored by Gensini or SPS, but not CACS. sLOX-1 also significantly improved the prediction of the incidence of obstructive CAD, defined as stenosis in any vessel >75%. The predictive value of sLOX-1 was significantly greater in the subgroup of patients who did not have any of the standard modifiable cardiovascular risk factors (SMuRFs). sLOX-1 is associated with CAD severity and is the first biomarker shown to have utility for risk prediction in the SMuRFless population.

Effects of Tofogliflozin and Anagliptin Alone or in Combination on Glucose Metabolism and Atherosclerosis-Related Markers in Patients with Type 2 Diabetes Mellitus

Purpose

In people with type 2 diabetes mellitus (T2DM), both glucose metabolism abnormalities and atherosclerosis risk are significant concerns. This study aims to investigate the effects of the sodium-glucose cotransporter 2 inhibitor tofogliflozin (TOFO) and the dipeptidyl peptidase-4 inhibitor anagliptin (ANA) on markers of glucose metabolism and atherosclerosis when administered individually or in combination.

Methods

Fifty T2DM patients were divided into two groups (receiving either TOFO or ANA monotherapy) and observed for 12 weeks (observation points: 0 and 12 weeks). The TOFO and ANA groups were then further treated with ANA and TOFO, respectively, and the patients were observed for an additional 36 weeks (observation points: 24 and 48 weeks). Therapeutic effects and various biomarkers were compared between the two groups at the observation points.

Results

Combination therapy led to significant improvements in HbA1c levels and atherosclerosis markers. Additionally, the TOFO pretreatment group exhibited significant reductions in sLOX-1 and IL-6 levels.

Conclusion

The increase in sLOX-1 and IL-6 levels, which indicates the response of scavenger receptors to oxidized low-density lipoproteins in people with T2DM, is mitigated following TOFO and ANA combination therapy. TOFO alone or in combination with ANA may be beneficial for preventing atherosclerosis development in people with T2DM, in addition to its effect on improving HbA1c levels.

Postmortem pericardial fluid sLOX-1 levels and LOX-1 immunostaining in forensic specimens: Relation to cause of death

Lectin-like oxidized LDL receptor-1 (LOX-1) is the endothelial receptor for oxidized LDL. This receptor's extracellular domain is released into the blood as soluble LOX-1 (sLOX-1) and has been linked to ischemic heart disease (IHD), cerebrovascular diseases (CVDs), obesity, and diabetes. We recently reported that sLOX-1 fluid levels in postmortem pericardial fluid were comparable to clinical values in live patients and that significant increases in sLOX-1 were observed in patients with IHD. However, postmortem serum and urine sLOX-1 levels were higher than serum levels in living patients. Here, we conducted LOX-1 immunostaining in forensic specimens (aorta and heart) and evaluated pericardial fluid sLOX-1 in 221 medicolegal autopsy cases (67 IHD, 11 CVD, 17 inflammatory diseases, and 126 control cases) with a postmortem interval < 72 h to assess the diagnostic efficiency of postmortem pericardial fluid sLOX-1. Furthermore, we evaluated the relationships between pericardial fluid sLOX-1 and body mass index (BMI), blood HbA1c, serum C-reactive protein (CRP), high-density lipoprotein cholesterol (HDL-C), and low-density-lipoprotein cholesterol (LDL-C). LOX-1 immunostaining positivity was found in the aortic intima. Pericardial fluid sLOX-1 levels were considerably higher in patients with IHD and CVD. However, there were no significant differences in patients with inflammatory diseases and controls. No associations between pericardial fluid sLOX-1 and BMI, HbA1c, CRP, HDL-C, or LDL-C were found. These results indicate sLOX-1 utility in the postmortem diagnosis of IHD and CVD.

Lectin-Like Oxidized Low-Density Lipoprotein Receptor 1 Inhibition in Type 2 Diabetes: Phase 1 Results

Background Blockade of the lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is a potentially attractive mechanism for lowering inflammatory and lipid risk in patients with atherosclerosis. This study aims to assess the safety, tolerability, and target engagement of MEDI6570, a high-affinity monoclonal blocking antibody to LOX-1. Methods and Results This phase 1, first-in-human, placebo-controlled study (NCT03654313) randomized 88 patients with type 2 diabetes to receive single ascending doses (10, 30, 90, 250, or 500 mg) or multiple ascending doses (90, 150, or 250 mg once monthly for 3 months) of MEDI6570 or placebo. Primary end point was safety; secondary and exploratory end points included pharmacokinetics, immunogenicity, free soluble LOX-1 levels, and change in coronary plaque volume. Mean age was 57.6/58.1 years in the single ascending doses/multiple ascending doses groups, 31.3%/62.5% were female, and mean type 2 diabetes duration was 9.7/8.7 years. Incidence of adverse events was similar among cohorts. MEDI6570 exhibited nonlinear pharmacokinetics, with terminal half-life increasing from 4.6 days (30 mg) to 11.2 days (500 mg), consistent with target-mediated drug disposition. Dose-dependent reductions in mean soluble LOX-1 levels from baseline were observed (>66% at 4 weeks and 71.61-82.96% at 10 weeks in the single ascending doses and multiple ascending doses groups, respectively). After 3 doses, MEDI6570 was associated with nonsignificant regression of noncalcified plaque volume versus placebo (-13.45 mm3 versus -8.25 mm3). Conclusions MEDI6570 was well tolerated and demonstrated dose-dependent soluble LOX-1 suppression and a pharmacokinetic profile consistent with once-monthly dosing. Registration URL: https://clinicaltrials.gov/; Unique identifier: NCT03654313.

Soluble lectin-like oxidized low-density Lipoproteinreceptor-1 and recurrent stroke: A nested case-control study

MAIN PROBLEM

The prognostic value of soluble lectin-like oxidized low-density lipoproteinreceptor-1 (sLOX-1) for stroke was unclearly. This study aimed to investigate the association between sLOX-1 and recurrent stroke in patients with acute ischemic stroke (AIS) or transient ischemic attack (TIA).

METHODS

Data were obtained from the Third China National Stroke Registry. Eligible cases consisted of 400 patients who developed recurrent stroke within 1-year follow-up, 800 controls were selected using age- and sex-matched with a 1:2 case-control ratio. Conditional logistic regressions were used to evaluate the association between sLOX-1 and recurrent stroke.

RESULTS

Among 1200 patients included in this study, the median (interquartile range) of sLOX-1 was 247.12 (132.81-413.58) ng/L. After adjustment for conventional confounding factors, the odds ratio with 95% confidence interval in the highest tertile versus the lowest tertile was 2.23 (1.61-3.08) for recurrent stroke, 2.31 (1.64-3.24) for ischemic stroke, 2.30 (1.66-3.19) for combined vascular events within 1-year follow-up. Furthermore, the addition of sLOX-1 to a conventional risk model had an incremental effect on predictive value for recurrent stroke (C-statistics 0.76, p < 0.0001; integrated discrimination improvement 13.38%, p < 0.0001; net reclassification improvement 55.39%, p < 0.0001). Similar results were observed when the timepoint was set up as 3 months. Subgroup analysis showed the association between higher sLOX-1 and recurrent stroke was more pronounced in patients with a history of stroke (p for interaction = 0.0062).

CONCLUSIONS

sLOX-1 was positively associated with the risk of recurrent stroke, which may be a candidate biomarker to improve risk stratification of recurrent stroke.

Serum levels of sLOX-1 and Lp-PLA2 can predict the prognosis of acute cerebral infarction with a high specificity

Soluble lectin-like oxidized low-density lipoprotein receptor-1 (sLOX-1) and lipoprotein-associated phospholipase A2 (Lp-PLA2) plays an important role in acute cerebral infarction (ACI), whereas its clinical value in predicting the prognosis is unclear. Thus, this study aimed to explore this issue. A total of 127 ACI patients were included in this prospective observational study. The concentrations of sLOX-1 and Lp-PLA2 in serum were measured and their relationship with a poor prognosis 90 days after the onset of ACI was analyzed. We found that patients with poor prognosis had higher mean serum levels of sLOX-1 and Lp-PLA2. The level of sLOX-1 and Lp-PLA2 could predict the functional outcome of ACI. At the optimal cut off value of sLOX-1 level (1257.92 ng/ml), the sensitivity and specificity for the poor functional outcome were 0.69 and 0.753, respectively, and the area under ROC curve (AUC) was 0.727. Similarly, the optimal value for Lp-PLA2 level was 160.9 ng/ml, at which the sensitivity and specificity were 0.643 and 0.835, respectively; and the AUC was 0.758. When the two biomarkers were used in combination, the AUC was 0.855, and the sensitivity and specificity were 0.643 and 0.976, respectively, indicating a significant improvement of the diagnostic specificity. The level of sLOX-1 or Lp-PLA2 could thus serve as useful biomarkers to predict the functional outcome of ACI. Combined use of both indicators is better than the use of either single indicator, and provides the highest specificity in predicting poor prognosis.

Soluble Lectin-Like Oxidized Low-Density Lipoprotein Receptor-1 Level is Related to Clinical Prognosis In Patients with Acute Atherosclerosis-related Ischemic Stroke

To investigate the associations between soluble Lectin-like Oxidized Low-density lipoprotein receptor-1 (sLOX-1) and clinical prognosis, especially infarct volume in patients with acute atherosclerosis-related ischemic stroke. We recruited acute ischemic stroke patients within 3 days after onset. Patients were stratified into 3 groups by sLOX-1 level. Initial stroke severity was assessed using the National Institutes of Health Stroke Scale scores, and infarct volume was measured using DWI by ITK-SNAP software. The clinical prognosis was evaluated by DWI volume, clinical response at discharge, and functional outcome at 90 days. Spearman rank correlation analysis was used to examine associations between circulating sLOX-1 levels and infarct volumes. Logistic regression was used to explore the relationship between sLOX-1 levels and clinical prognosis. A total of 207 patients were included in our study. The median DWI volume in the lowest sLOX-1 tertile was 1.98 cm³, smaller than 4.26 cm³ in the highest sLOX-1 group. The Spearman rank correlation coefficient between sLOX-1 levels and DWI volume was 0.47 (P < .01). Compared with the highest sLOX-1 tertiles, patients in the lowest sLOX-1 tertile had a higher risk of favorable functional outcome at 90 days (OR = 3.47, 95% CI, 1.21-9.96) after adjusting traditional risk factors. However, there was no difference between sLOX-1 level and clinical response at discharge. For patients with acute atherosclerosis-related ischemic stroke, circulating sLOX-1 level is correlated with DWI volume in the acute phase and favorable functional outcome at 90 days, but not with the clinical response at discharge.

Non-stenotic Carotid Plaques in Embolic Stroke of Unknown Source

Embolic stroke of unknown source (ESUS) represents one in five ischemic strokes. Ipsilateral non-stenotic carotid plaques are identified in 40% of all ESUS. In this narrative review, we summarize the evidence supporting the potential causal relationship between ESUS and non-stenotic carotid plaques; discuss the remaining challenges in establishing the causal link between non-stenotic plaques and ESUS and describe biomarkers of potential interest for future research. In support of the causal relationship between ESUS and non-stenotic carotid plaques, studies have shown that plaques with high-risk features are five times more prevalent in the ipsilateral vs. the contralateral carotid and there is a lower incidence of atrial fibrillation during follow-up in patients with ipsilateral non-stenotic carotid plaques. However, non-stenotic carotid plaques with or without high-risk features often coexist with other potential etiologies of stroke, notably atrial fibrillation (8.5%), intracranial atherosclerosis (8.4%), patent foramen ovale (5-9%), and atrial cardiopathy (2.4%). Such puzzling clinical associations make it challenging to confirm the causal link between non-stenotic plaques and ESUS. There are several ongoing studies exploring whether select protein and RNA biomarkers of plaque progression or vulnerability could facilitate the reclassification of some ESUS as large vessel strokes or help to optimize secondary prevention strategies.

sLOX-1: A Molecule for Evaluating the Prognosis of Recurrent Ischemic Stroke

Several clinical parameters and biomarkers have been proposed as prognostic markers for stroke. However, it has not been clarified whether the risk factors affecting the prognosis of patients with recurrent and first-ever stroke are similar. In this study, we aimed to explore the relationship between soluble lectin-like oxidized low-density lipoprotein receptor 1 (sLOX-1) levels and the prediction of the functional outcome in patients with recurrent and first-ever stroke. A total of 266 patients with recurrent and first-ever stroke, who underwent follow-up for 3 months, were included in this study. Plasma samples were collected within 24 h after onset. The results showed that biomarkers for the prognosis of patients with recurrent stroke were different from that of those with first-ever stroke. sLOX-1 levels were correlated with modified Rankin Scale scores of patients with recurrent stroke alone (r = 0.3232, p = 0.001). sLOX-1 levels were also associated with an increased risk of unfavorable outcomes in patients with recurrent stroke with an adjusted odds ratio of 1.489 (95% confidence interval, 1.204–1.842, p < 0.0001). Combining the risk factors showed greater accuracy for prognosis, yielding a sensitivity of 93.2% and a specificity of 75%, with an area under the curve of 0.916, evaluated by the receiver operating characteristic curve. These findings suggest that the diagnosis and prognosis are different between patients with recurrent stroke and those with first-ever stroke, and sLOX-1 level is an independent prognostic marker in patients with recurrent stroke.

Inflammatory Markers in Cardiovascular Disease; Lessons Learned and Future Perspectives

BACKGROUND

Cardiovascular disease (CVD) still remains the leading cause of morbidity and mortality worldwide. It is now established that inflammation plays a crucial role in atherosclerosis and atherothrombosis, and thus, it is closely linked to cardiovascular disease.

OBJECTIVE

The aim of the present review is to summarize and critically appraise the most relevant evidence regarding the potential use of inflammatory markers in the field of CVD.

METHODS

We conducted a comprehensive research of the relevant literature, searching MEDLINE from its inception until November 2018, primarily for meta-analyses, randomized controlled trials and observational studies.

RESULTS

Established markers of inflammation, mainly C-reactive protein, have yielded significant results both for primary and secondary prevention of CVD. Newer markers, such as lipoprotein-associated phospholipase A2, lectin-like oxidized low-density lipoprotein receptor-1, cytokines, myeloperoxidase, cell adhesion molecules, matrix metalloproteinases, and the CD40/CD40 ligand system, have been largely evaluated in human studies, enrolling both individuals from the general population and patients with established CVD. Some markers have yielded conflicting results; however, others are now recognized not only as promising biomarkers of CVD, but also as potential therapeutic targets, establishing the role of anti-inflammatory and pleiotropic drugs in CVD.

CONCLUSION

There is significant evidence regarding the role of consolidated and novel inflammatory markers in the field of diagnosis and prognosis of CVD. However, multimarker model assessment, validation of cut-off values and cost-effectiveness analyses are required in order for those markers to be integrated into daily clinical practice.

Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1): a crucial driver of atherosclerotic cardiovascular disease

Cardiovascular diseases (CVDs), specifically lipid-driven atherosclerotic CVDs, remain the number one cause of death worldwide. The lectin-like oxidized low-density lipoprotein (LDL) receptor-1 (LOX-1), a scavenger receptor that promotes endothelial dysfunction by inducing pro-atherogenic signalling and plaque formation via the endothelial uptake of oxidized LDL (oxLDL) and electronegative LDL, contributes to the initiation, progression, and destabilization of atheromatous plaques, eventually leading to the development of myocardial infarction and certain forms of stroke. In addition to its expression in endothelial cells, LOX-1 is expressed in macrophages, cardiomyocytes, fibroblasts, dendritic cells, lymphocytes, and neutrophils, further implicating this receptor in multiple aspects of atherosclerotic plaque formation. LOX-1 holds promise as a novel diagnostic and therapeutic target for certain CVDs; therefore, understanding the molecular structure and function of LOX-1 is of critical importance. In this review, we highlight the latest scientific findings related to LOX-1, its ligands, and their roles in the broad spectrum of CVDs. We describe recent findings from basic research, delineate their translational value, and discuss the potential of LOX-1 as a novel target for the prevention, diagnosis, and treatment of related CVDs.

Diagnostic and prognostic blood biomarkers in vascular dementia: From the viewpoint of ischemic stroke

Reliable quantitative blood biomarkers are important in vascular dementia (VaD) because early diagnosis and therapeutic intervention are effective in preventing progression of dementia. Although many blood biomarkers for acute ischemic stroke (AIS) or VaD have been reported, there are few reliable blood biomarkers. VaD and AIS have similar pathological conditions that are associated with small vessel disease (SVD) such as oxidative stress, inflammation, endothelial dysfunction, and neuronal injury. Therefore, it may be possible to find superior blood biomarkers of VaD among AIS blood biomarkers. Owing to recent developments, noncoding RNAs such as microRNA and long noncoding RNA, which can be analyzed using a single drop of blood, are also particularly reliable VaD markers because they stably reflect brain tissue damage. A multimarker combining several blood biomarkers or artificial intelligence technology may also be beneficial to compensate for insufficiencies of a single blood biomarker. This review describes the blood biomarkers of VaD and how they are related to blood biomarkers of AIS.

Role of LOX-1 (Lectin-Like Oxidized Low-Density Lipoprotein Receptor 1) as a Cardiovascular Risk Predictor: Mechanistic Insight and Potential Clinical Use

Atherosclerosis, the underlying cause of cardiovascular disease (CVD), is a worldwide cause of morbidity and mortality. Reducing ApoB-containing lipoproteins-chiefly, LDL (low-density lipoprotein)-has been the main strategy for reducing CVD risk. Although supported by large randomized clinical trials, the persistence of residual cardiovascular risk after effective LDL reduction has sparked an intense search for other novel CVD biomarkers and therapeutic targets. Recently, Lox-1 (lectin-type oxidized LDL receptor 1), an innate immune scavenger receptor, has emerged as a promising target for early diagnosis and cardiovascular risk prediction and is also being considered as a treatment target. Lox-1 was first described as a 50 kDa transmembrane protein in endothelial cells responsible for oxLDL (oxidized LDL) recognition, triggering downstream pathways that intensify atherosclerosis via endothelial dysfunction, oxLDL uptake, and apoptosis. Lox-1 is also expressed in platelets, where it enhances platelet activation, adhesion to endothelial cells, and ADP-mediated aggregation, thereby favoring thrombus formation. Lox-1 was also identified in cardiomyocytes, where it was implicated in the development of cardiac fibrosis and myocyte apoptosis, the main determinants of cardiac recovery following an ischemic insult. Together, these findings have revealed that Lox-1 is implicated in all the main steps of atherosclerosis and has encouraged the development of immunoassays for measurement of sLox-1 (serum levels of soluble Lox-1) to be used as a potential CVD biomarker. Finally, the recent development of synthetic Lox-1 inhibitors and neutralizing antibodies with promising results in animal models has made Lox-1 a target for drug development. In this review, we discuss the main findings regarding the role of Lox-1 in the development, diagnosis, and therapeutic strategies for CVD prevention and treatment.

Search for Reliable Circulating Biomarkers to Predict Carotid Plaque Vulnerability

Atherosclerosis is responsible for 20% of ischemic strokes, and the plaques from the internal carotid artery the most frequently involved. Lipoproteins play a key role in carotid atherosclerosis since lipid accumulation contributes to plaque progression and chronic inflammation, both factors leading to plaque vulnerability. Carotid revascularization to prevent future vascular events is reasonable in some patients with high-grade carotid stenosis. However, the degree of stenosis alone is not sufficient to decide upon the best clinical management in some situations. In this context, it is essential to further characterize plaque vulnerability, according to specific characteristics (lipid-rich core, fibrous cap thinning, intraplaque hemorrhage). Although these features can be partly detected by imaging techniques, identifying carotid plaque vulnerability is still challenging. Therefore, the study of circulating biomarkers could provide adjunctive criteria to predict the risk of atherothrombotic stroke. In this regard, several molecules have been found altered, but reliable biomarkers have not been clearly established yet. The current review discusses the concept of vulnerable carotid plaque, and collects existing information about putative circulating biomarkers, being particularly focused on lipid-related and inflammatory molecules.

LOX-1 (Lectin-Like Oxidized Low-Density Lipoprotein Receptor-1) Deletion Has Protective Effects on Stroke in the Genetic Background of Stroke-Prone Spontaneously Hypertensive Rat

Background and Purpose- oxLDL (oxidized low-density lipoprotein) has been known for its potential to induce endothelial dysfunction and used as a major serological marker of oxidative stress. Recently, LOX-1 (lectin-like oxidized low-density lipoprotein receptor-1), a lectin-like receptor for oxLDL, has attracted attention in studies of neuronal apoptosis and stroke. We aim to investigate the impact of LOX-1-deficiency on spontaneous hypertension-related brain damage in the present study. Methods- We generated a LOX-1 deficient strain on the genetic background of stroke-prone spontaneously hypertensive rat (SHRSP), an animal model of severe hypertension and spontaneous stroke. In this new disease model with stroke-proneness, we monitored the occurrence of brain abnormalities with and without salt loading by multiple procedures including T₂ weighted magnetic resonance imaging and also explored circulatory miRNAs as diagnostic biomarkers for cerebral ischemic injury by microarray analysis. Results- Both T₂ weighted magnetic resonance imaging abnormalities and physiological parameter changes could be detected at significantly delayed timing in LOX-1 knockout rats compared with wild-type SHRSP, in either case of normal rat chow and salt loading (P<0.005 in all instances; n=11-20 for SHRSP and n=13-23 for LOX-1 knockout rats). There were no significant differences in the form of magnetic resonance imaging findings between the strains. A number of miRNAs expressed in the normal rat plasma, including rno-miR-150-5p and rno-miR-320-3p, showed significant changes after spontaneous brain damage in SHRSP, whereas the corresponding changes were modest or almost unnoticeable in LOX-1 knockout rats. There appeared to be the lessening of correlation of postischemic miRNA alterations between the injured brain tissue and plasma in LOX-1 knockout rats. Conclusions- Our data show that deficiency of LOX-1 has a protective effect on spontaneous brain damage in a newly generated LOX-1-deficient strain of SHRSP. Further, our analysis of miRNAs as biomarkers for ischemic brain damage supports a potential involvement of LOX-1 in blood brain barrier disruption after cerebral ischemia. Visual Overview- An online visual overview is available for this article.

Elevated serum pentraxin 3 levels might predict the diagnosis of branch atheromatous disease at a very early stage

BACKGROUND AND PURPOSE

Branch atheromatous disease (BAD) is one of the stroke subtypes caused by occlusion at the origin of a deep penetrating artery of the brain and is associated with a microatheroma or a junctional plaque. Patients with BAD often develop progressive worsening of neurologic deficits, although these patients often present minor stroke with clinical characteristics of lacunar syndrome at the onset. Pentraxin 3 (PTX3) is known to be a key molecule involved in the pathogenesis of atherosclerosis. Although a high level of serum PTX3 is observed in patients with acute coronary syndrome, there are no reports on PTX3 levels in patients with BAD. This study aimed to investigate whether serum PTX3 levels can distinguish BAD from other stroke subtypes.

METHODS

We investigated 93 patients with ischaemic stroke. Serum PTX3 levels on admission were measured using enzyme-linked immunosorbent assay in patients with BAD and those with other stroke subtypes (each n ≥ 20).

RESULTS

The median PTX3 levels in patients with BAD (4840 pg/mL) were higher than those with other subtypes of stroke (3397 pg/mL in lacunar stroke, 1298 pg/mL in large-artery atherosclerosis, 1470 pg/mL in cardioaortic embolism and 1006 pg/mL in control) (all P < 0.01).

CONCLUSION

Our results suggest that elevated serum PTX3 levels might predict the diagnosis of BAD at a very early stage.

High Levels of Soluble Lectinlike Oxidized Low-Density Lipoprotein Receptor-1 Are Associated With Carotid Plaque Inflammation and Increased Risk of Ischemic Stroke

Background When the lectinlike oxidized low-density lipoprotein (ox LDL) receptor-1 ( LOX -1), a scavenger receptor for ox LDL , binds ox LDL , processes leading to endothelial dysfunction and inflammation are promoted. We aimed to study release mechanisms of LOX -1 and how circulating levels of soluble LOX -1 ( sLOX -1) relate to plaque inflammation and future risk for ischemic stroke. Methods and Results Endothelial cells and leukocytes were used to study release of sLOX -1. Plasma levels of sLOX -1 were determined in 4703 participants in the Malmö Diet and Cancer cohort. Incidence of ischemic stroke was monitored. For 202 patients undergoing carotid endarterectomy, levels of sLOX -1 were analyzed in plasma and plaque homogenates and related to plaque inflammation factors. Endothelial cells released sLOX -1 when exposed to ox LDL . A total of 257 subjects experienced stroke during a mean follow-up of 16.5 years. Subjects in the highest tertile of sLOX -1 had a stroke hazard ratio of 1.75 (95% CI, 1.28-2.39) compared with those in the lowest tertile after adjusting for age and sex. The patients undergoing carotid endarterectomy had a significant association between plasma sLOX -1 and the plaque content of sLOX -1 ( r=0.209, P=0.004). Plaques with high levels of sLOX -1 had more ox LDL , proinflammatory cytokines, and matrix metalloproteinases. Conclusions Our findings demonstrate that ox LDL induces the release of sLOX -1 from endothelial cells and that circulating levels of sLOX -1 correlate with carotid plaque inflammation and risk for ischemic stroke. These observations provide clinical support to experimental studies implicating LOX -1 in atherosclerosis and its possible role as target for cardiovascular intervention.

Serum soluble lectin-like oxidized low-density lipoprotein receptor-1 as a biomarker of delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage

OBJECTIVE

Delayed cerebral ischemia (DCI) greatly contributes to the high morbidity and mortality of aneurysmal subarachnoid hemorrhage (aSAH) patients. Expression of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) was substantially raised in the basilar arterial wall of SAH rabbits. We attempted to ascertain the relationship between serum soluble LOX-1 (sLOX-1) levels and the occurrence of DCI after aSAH.

MATERIALS AND METHODS

We enrolled 125 aSAH patients and 125 healthy controls. Serum sLOX-1 levels were quantified using commercial enzyme-linked immunosorbent assay kit. The relationship between sLOX-1 levels and DCI was analyzed utilizing the multivariate logistic regression analysis.

RESULTS

Serum sLOX-1 levels were significantly higher in stroke patients than in controls (median: 1,450.2 vs. 445.7 pg/ml, p < .001). Serum sLOX-1 levels were highly correlated with World Federation of Neurological Surgeons (WFNS) scores, Hunt-Hess scores, and modified Fisher scores (r = .574, .625, and .569, respectively). Forty-two patients (33.6%) experienced DCI. Serum sLOX-1 > 1,450.2 pg/ml, WFNS scores and modified Fisher scores were the independent predictors of DCI. Under receiver operating characteristic curve, serum sLOX-1 levels exhibited a significant discriminatory capability (area under curve 0.825, 95% confidence interval 0.747-0.887). The predictive power of serum sLOX-1 levels was similar to those of WFNS scores and modified Fisher grade (both p > .05). Moreover, serum sLOX-1 levels significantly improved their predictive capability (both p < .05).

CONCLUSIONS

Serum soluble LOX-1, in positive association with hemorrhagic severity, appears to have the potential to become a promising predictor of DCI after aSAH.

Detection of a High Ratio of Soluble to Membrane-Bound LOX-1 in Aspirated Coronary Thrombi From Patients With ST-Segment-Elevation Myocardial Infarction

Background

The circulating level of soluble lectin‐like oxidized low‐density lipoprotein receptor‐1 (sLOX‐1) is a valuable biomarker of acute myocardial infarction (AMI). The most electronegative low‐density lipoprotein, L5, signals through LOX‐1 to trigger atherogenesis. We examined the characteristics of LOX‐1 and the role of L5 in aspirated coronary thrombi of AMI patients.

Methods and Results

Intracoronary thrombi were aspirated by performing interventional thrombosuction in patients with ST‐segment–elevation myocardial infarction (STEMI; n=32) or non–ST‐segment–elevation myocardial infarction (n=12). LOX‐1 level and the ratio of sLOX‐1 to membrane‐bound LOX‐1 were higher in thrombi of STEMI patients than in those of non–ST‐segment–elevation myocardial infarction patients. In all aspirated thrombi, LOX‐1 colocalized with apoB100. When we explored the role of L5 in AMI, deconvolution microscopy showed that particles of L5 but not L1 (the least electronegative low‐density lipoprotein) quickly formed aggregates prone to retention in thrombi. Treating human monocytic THP‐1 cells with L5 or L1 showed that L5 induced cellular adhesion and promoted the differentiation of monocytes into macrophages in a dose‐dependent manner. In a second cohort of AMI patients, the L5 percentage and plasma concentration of sLOX‐1 were higher in STEMI patients (n=33) than in non–ST‐segment–elevation myocardial infarction patients (n=25), and sLOX‐1 level positively correlated with L5 level in AMI patients.

Conclusions

The level of LOX‐1 and the ratio of sLOX‐1 to membrane‐bound LOX‐1 in aspirated thrombi, as well as the circulating level of sLOX‐1 were higher in STEMI patients than in non–ST‐segment–elevation myocardial infarction patients. L5 may play a role in releasing a high level of sLOX‐1 into the circulation of STEMI patients.

Baseline Serum sLOX-1 Concentrations Are Associated with 2-Year Major Adverse Cardiovascular and Cerebrovascular Events in Patients after Percutaneous Coronary Intervention

Background

Soluble lectin-like oxidized low-density lipoprotein receptor-1 (sLOX-1) may be a potential biomarker of coronary artery disease (CAD) and stroke.

Objective

We aimed to investigate the association and prognostic value of elevated sLOX-1 concentrations with regard to long-term major adverse cardiovascular and cerebrovascular events (MACCEs) in patients with CAD undergoing primary percutaneous coronary intervention (PCI).

Methods

A total of 1011 patients were enrolled. Serum sLOX-1 concentrations were detected by the enzyme-linked immunosorbent assay (ELISA). Patients were followed for 2 years. Multivariate Cox regression and Kaplan-Meier survival curve were explored to assess the association between sLOX-1 and MACCEs. A receiver operating characteristic (ROC) curve was used to evaluate the diagnostic efficacy of sLOX-1.

Results

Two-year MACCEs were associated with serum sLOX-1 concentrations (HR 1.278, 95% CI 1.019-1.604, P = 0.034), left main disease (HR 2.938, 95% CI 1.246-6.925, P = 0.014), small-caliber stents used (HR 2.207, 95% CI 1.189-4.095, P = 0.012), and total stent length (HR 1.057, 95% CI 1.005-1.112, P = 0.030). Serum sLOX-1 concentration ≥ 1.10 ng/ml had maximum sensitivity and specificity in predicting the occurrence of 2-year MACCEs (P < 0.001). Patients with higher serum sLOX-1 concentrations showed a significantly higher incidence of MACCEs in the Kaplan-Meier curve (P < 0.001). The combination of any of the risk factors identified in multiple Cox regression was associated with a stepwise increase in MACCE rate (P < 0.001).

Conclusions

High baseline serum sLOX-1 concentration predicts 2-year MACCEs and shows an additional prognostic value to conventional risk factors in patients after primary PCI. sLOX-1 determination might play a complementary role in the risk stratification of patients with CAD treated with PCI.

Serum soluble lectin-like oxidized low-density lipoprotein receptor-1 concentrations and prognosis of aneurysmal subarachnoid hemorrhage

BACKGROUND

Oxidized low-density lipoprotein (ox-LDL) and its receptor, lectin-like ox-LDL receptor-1 (LOX-1) are involved in the pathogenesis of atherosclerosis. Expression of LOX-1 was substantially raised in the basilar arterial wall of subarachnoid hemorrhage (SAH) rabbits. We ascertained the relationship between serum soluble LOX-1 concentrations and functional outcome after human aneurysmal SAH.

METHODS

We enrolled 94 aneurysmal SAH patients and 94 healthy controls. Serum soluble TOX-1 concentrations were quantified using commercial enzyme-linked immunosorbent assay kit. A poor outcome was defined as Glasgow outcome scale score of 1-3.

RESULTS

Median values of serum soluble LOX-1 in stroke patients were significantly higher than those in controls (1.5 vs. 0.4 ng/ml, P < 0.001). Thirty patients (31.9%) had a poor outcome at 6 months after stroke. Serum soluble LOX-1 was a strong predictor of poor outcome (OR 5.20, 95% CI 1.25-22.04). Serum soluble LOX-1 concentrations exhibited a significant discriminatory capability (area under curve 0.811, 95% confidence interval 0.717-0.884). The predictive powers of World Federation of Neurological Surgeons grade, Hunt-Hess grade, modified Fisher grade, and serum soluble LOX-1 concentrations were comparable (all P > 0.05).

CONCLUSIONS

Serum soluble LOX-1 appears to have the potential to become a promising prognostic predictor after human aneurysmal SAH.

Soluble Lectin-like Oxidized Low-Density Lipoprotein Receptor 1 Predicts the Changes of Rheumatoid Factor Titers in Rheumatoid Arthritis

OBJECTIVE

The aim of this longitudinal study was to examine the clinical significance of soluble lectin-like oxidized low-density lipoprotein receptor 1 (sLOX-1) in patients with rheumatoid arthritis.

METHODS

We gathered demographic and clinical data for a large rheumatoid arthritis cohort at 3 time points. Blood samples were collected at each time point; the number of samples was 282 cases in 2012, 431 cases in 2013, and 500 cases in 2014. Plasma sLOX-1 was measured by enzyme-linked immunosorbent assay. Correlations between sLOX-1 and clinical data were analyzed. Predictive factors associated with changes in sLOX-1 and rheumatoid factor (RF) were analyzed by multivariate linear regression.

RESULTS

Plasma sLOX-1 level was significantly correlated with RF titer and other clinical parameters. The longitudinal analyses showed that changes in sLOX-1 were significantly correlated with changes in RF titers and with those at baseline. Multivariate linear regression analysis revealed that changes in RF and baseline RF were predictive factors for changes in sLOX-1. Conversely, the changes in RF were significantly correlated with the changes in sLOX-1 in all years. A stepwise regression analysis showed that the change in sLOX-1 was a predictive factor for the change in RF.

CONCLUSIONS

The change in sLOX-1 has predictive value for assessing the change in RF, indicating the usefulness of sLOX-1 in clinical practice.

Emerging Biomarkers of Oxidative Stress in Acute and Stable Coronary Artery Disease: Levels and Determinants

Background: Oxidative stress is crucial in the pathogenesis of atherosclerosis and acute myocardial infarction (AMI). Under the generic terms “oxidative stress” (OS), many biomarkers belonging to different pathways have been proposed. Aim: To compare the levels of recently proposed OS-related parameters in acute coronary syndromes (ACS) and stable coronary artery disease (CAD), to evaluate their effectiveness as additive risk or illness indicators of stable and acute ischemic events, and their response over time during the course of AMI. Methods: 76 ACS, 77 CAD patients, and 63 controls were enrolled in the study. Different OS-related biomarkers, including reactive oxygen metabolites (ROM), the total antioxidant capacity (OXY), nitrite/nitrate (final nitric oxide products, NO_x), and Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), were evaluated. Moreover, time response during AMI course (admission, and 6, 12, 18, 24, 36, and 48 hours after, T0-T6, respectively) and correlation with traditional cardiovascular (CV) risk factors (age, gender, hypertension, diabetes mellitus, dyslipidemia, smoking habit) were also assessed. Results: Over time, ROM progressively increased while OXY and NO_x decreased. Kinetics of LOX-1 during AMI shows that this biomarker boosts early during the acute event (T1 and T2) and then progressively decreases, being significantly lower from T0 to T6. Different OS-related biomarkers were differentially associated with CV risk factors and CAD or ACS presence. Conclusion: Differences in OS-related biomarkers (between groups, according to the response over time during AMI, and to the presence of CV risk factors) confirmed OS involvement in the transition from healthy status to stable CAD and ACS, although evidencing the heterogeneous nature of redox processes. In future, a multi-marker panel including different biomarkers and pathways of oxidative stress could be evaluated as an additive tool to be used in the CV prevention, diagnosis, patient stratification, and treatment.

Evaluation of hs-CRP and sLOX-1 Levels in Moderate-to-High Risk Acute Coronary Syndromes

OBJECTIVE

Risk stratification and prompt treatment are essential for the management of acute coronary syndromes (ACS) and prediction of future prognosis. Subclinical vascular inflammation and novel biomarkers play an important role in the clinical evaluation of ACS patients.

METHODS

We enrolled patients who were admitted to emergency service with unstable angina or non- ST segment elevated ACS (NSTE-ACS) in the study population. Coronary artery disease (CAD) complexity was determined via evaluation of angiographical views and peripheral venous blood samples were collected to measure highly sensitive C-reactive protein (hs-CRP) and soluble form of Lectin-like OxLDL receptor-1 (sLOX-1) levels.

RESULTS

A total of 40 patients were enrolled in the study population, mean age was 65.1±13.8 years and male gender percentage was 52.5%. Twenty-nine of patients had NSTE-ACS and 11 patients had unstable angina presentation. The modified Gensini scores were higher for patients with elevated hs- CRP and sLOX-1 levels.

CONCLUSION

Vascular inflammation displays the onset of ACS and it is related to more complex CAD in these patients. An increase in sLOX-1 expression is closely related to anatomical complexity of CAD in ACS.

LOX-1 and atherosclerotic-related diseases

Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), a scavenger receptor of oxidized low-density lipoprotein (ox-LDL) found in various cells, plays a crucial role in the formation and progression of atherosclerotic plaques. Animal studies have suggested that LOX-1 mediates the balance between internalization and degeneration of endothelial cells, thereby contributing to various steps in the atherosclerotic process, from initiation to plaque rupture. Under pathological conditions, the extracellular domain of membrane bound LOX-1 can be largely proteolytically cleaved into a soluble form (sLOX-1), which is proportional and linked to the LOX-1 expression level. Circulating levels of sLOX-1 are regarded as a risk biomarker for plaque rupture and acute coronary syndrome (ACS). Recently, studies have shown that sLOX-1 is also elevated in patients with acute stroke and can be a predictive biomarker for acute stroke. With the discovery of the vital role of LOX-1 in atherosclerosis, there is growing focus on the influence of LOX-1 in atherosclerotic-related diseases, including coronary arterial disease(CAD), stroke, and other cardiovascular events. Genetic polymorphisms of LOX-1 have been investigated and have been found to modulate the risk of these diseases. Most polymorphisms have been found to be risk factors, except for the splicing isoform LOXIN. This review concludes with a discussion of the potential future applications of LOX-1 for atherosclerotic-related diseases.

Prognostic Significance of Plasma CLEC-2 (C-Type Lectin-Like Receptor 2) in Patients With Acute Ischemic Stroke

Background and Purpose- CLEC-2 (C-type lectin-like receptor 2) is a C-type lectin receptor highly expressed on platelets with the prominent involvement in platelet activation, which was increased in coronary heart disease. Given the role of platelet activation in ischemic stroke and the connections between coronary heart disease and ischemic stroke, CLEC-2 might be a candidate marker of ischemic stroke. Here, we aimed to examine the prognostic significance of CLEC-2 in patients with acute ischemic stroke (AIS). Methods- Three hundred fifty-two patients with AIS within 7 days and 112 healthy controls were prospectively studied. Plasma CLEC-2 (pCLEC-2) and some conventional risk factors of stroke were examined. Stroke progression was defined as any new neurological symptoms/signs or any neurological worsening within 7 days after stroke onset, and poor prognosis was defined as modified Rankin Scale scores >2 at 90 days. The association between pCLEC-2 and stroke progression/prognosis was evaluated using regression models. Results- Patients with AIS had a significantly higher level of pCLEC-2 than that of healthy controls (P<0.05). Patients with AIS with progressive stroke or poor prognosis had a much higher level of pCLEC-2 compared with those with stable stroke or good prognosis (all P<0.05). Increasing pCLEC-2 was significantly associated with an increased risk of stroke progression (odds ratio, 1.97; 95% CI, 1.11-3.50; P=0.021) and poor prognosis (odds ratio, 1.70; 95% CI, 1.17-2.48; P=0.006). Patients with the highest pCLEC-2 level were 7- to 8-fold more likely to have stroke progression compared with the lowest quartile (odds ratio, 7.69; 95% CI, 1.43-41.41). Patients with the highest pCLEC-2 level were also more likely to have poor prognosis at 90 days (odds ratio, 5.58; 95% CI, 1.76-17.68). The optimal cutoff points of pCLEC-2 for predicting stroke progression and poor prognosis were 235.48 and 207.08 pg/mL, respectively. Conclusions- Increased pCLEC-2 was associated with stroke progression and poor prognosis at 90 days significantly, which indicates the prognostic role of pCLEC-2 in AIS. However, it needs to be confirmed in large-scale studies.

Lectin-Like Oxidized Low-Density Lipoprotein Receptor-1 Levels as a Biomarker of Acute Intracerebral Hemorrhage

BACKGROUND

Correct diagnosis of cerebral stroke type, hemorrhagic or ischemic, is essential in the early stage to establish the optimum treatment. The diagnosis is mainly determined based on imaging studies. Other more available diagnostic methods are desirable, such as blood sample examination. Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is very important in vascular dysfunction induced by oxidized low-density lipoprotein, including cell apoptosis. The present study evaluated LOX-1 as a biomarker for cerebral stroke.

SUBJECTS AND METHODS

Patients with newly diagnosed stroke were prospectively enrolled between February and July 2014. LOX-1 serum values were measured twice, within 24 hours and 2 months after the onset.

RESULTS

A total of 16 patients were enrolled; 7 patients with intracerebral hemorrhage (ICH) and 9 patients with cerebral infarction. Median LOX-1 values of patients with ICH and infarction in the acute phase were 1825.8 and 593.9 pg/mL, respectively, significantly higher in patients with ICH than in patients with infarction (P < .0001).

CONCLUSION

LOX-1 serum level has potential as a biomarker of ICH.

Osteoarthritis, cerebrovascular dysfunction and the common denominator of inflammation: a narrative review

OBJECTIVE

Population-based cohort studies suggest an association between osteoarthritis (OA) and cerebrovascular disease, yet the mechanisms underlying vascular comorbidities in OA remain unclear. The purpose of this narrative review is to discuss the literature examining inflammation in OA with a focus on physiological mechanisms, and whether overlapping mechanisms exist in cerebrovascular dysfunction.

METHOD

A literature search was conducted in PubMed using combinations of search terms: osteoarthritis, cerebrovascular (disease/dysfunction/risk), cardiovascular (disease/dysfunction/risk), aging/ageing, inflammation, inflammatory mediators, cytokine, c-reactive protein, interleukin, advanced glycation end-products, metabolic syndrome, reactive oxidative species, cognitive impairment, (vascular-related) dementia, small cerebral vessel disease, endothelial function, blood-brain barrier, gender/sex, hypertension, peripheral vascular health, and physical activity. Reference lists of identified articles were also researched manually.

RESULTS

Overlapping inflammatory factors that may contribute to onset and progression of both OA and cerebrovascular dysfunction are presented. We describe oxidative mechanisms involving pro-inflammatory cytokines and oxidative species, advanced glycation end-products, sex hormones, microvascular dysfunction and osteoprotegerin, and their specific roles in potentially contributing to OA and cerebrovascular dysfunction.

CONCLUSION

Synthesis of the current literature suggests future investigations may benefit from directly testing cerebrovascular hemodynamics and cognitive function in individuals with or at risk of OA to elucidate common physiological mechanisms.

Increased Levels of Lectin-Like Oxidized Low-Density Lipoprotein Receptor-1 in Ischemic Stroke and Transient Ischemic Attack

Background

Soluble lectin‐like oxidized low‐density lipoprotein receptor‐1 (sLOX‐1) has been shown to be increased in patients with acute ischemic stroke. Here, we evaluated plasma sLOX‐1 levels and vascular carotid plaque LOX‐1 (ie, OLR1) gene expression in patients with ischemic stroke and transient ischemic attack (TIA) with particular focus on their relation to time since symptom onset.

Methods and Results

Plasma sLOX‐1 (n=232) and carotid plaque OLR1 gene expression (n=146) were evaluated in patients who were referred to evaluation for carotid endarterectomy, as well as in healthy control plasma (n=81). Patients were categorized according to presence of acute ischemic stroke or transient ischemic attack (n=35) ≤7 days, >7 days ≤3 months (n=90), >3 months (n=40), or no reported symptoms before study inclusion (n=67). Our major findings were the following: (1) Patients with carotid atherosclerosis had increased plasma sLOX‐1 levels as compared with controls. (2) Plaque OLR1 mRNA levels were increased in carotid plaques (n=146) compared with nonatherosclerotic vessels (ie, common iliac arteries of organ donors, n=10). (3) There were no differences in sLOX plasma levels or OLR1 gene expression when analyzed according to the time since relevant cerebral ischemic symptoms. (4) Also patients with severe carotid atherosclerosis without any previous ischemic events had raised sLOX‐1 levels. (5) Immunostaining showed colocalization between LOX‐1 and macrophages within the carotid plaques. (6) Also patients with acute stroke (within 7 days) caused by atrial fibrillation (n=22) had comparable raised sLOX‐1 levels.

Conclusions

sLOX‐1 levels are elevated in patients with ischemic stroke and transient ischemic attack independent of cause and time since the ischemic event.

Role of sLOX-1 in intracranial artery stenosis and in predicting long-term prognosis of acute ischemic stroke

OBJECTIVE

The role of sLOX-1 in acute ischemic stroke still remains unclear. This study aims to demonstrate the value of sLOX-1 in evaluating degrees of intracranial artery stenosis and to predict prognosis in stroke.

METHODS

Two hundred and seventy-two patients were included in this study and basic data were collected within 72 hr on admission. We assessed the association between sLOX-1 levels and stroke conditions in one-year duration. After adjusting for potential confounders, regression analyses were performed.

RESULTS

We found that sLOX-1 levels were increased significantly in severe patients compared to the mild stroke group (p = .011). After adjusting confounders, sLOX-1 was associated with a poor functional outcome in patients with an adjusted OR of 2. 946 (95% CI, 1.788-4.856, p < .001). There was also positive correlation between sLOX-1 levels and the degrees of intracranial artery stenosis in the different groups (p = .029).

CONCLUSIONS

Our study demonstrated that sLOX-1 levels could be used to evaluate the severity of stroke and the degrees of intracranial artery stenosis. Furthermore, sLOX-1 could be exploited to predict the long-term functional outcome of stroke.

Contribution of lectin-like oxidized low-density lipoprotein receptor-1 and LOX-1 modulating compounds to vascular diseases

The lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is the major receptor for binding and uptake of oxidized low-density lipoprotein (oxLDL) in endothelial cells. LOX-1 is also expressed in macrophages, smooth muscle cells and platelets. Following internalization of oxLDL, LOX-1 initiates a vicious cycle from activation of pro-inflammatory signaling pathways, thus promoting an increased reactive oxygen species formation and secretion of pro-inflammatory cytokines. LOX-1 plays a pivotal role in the development of endothelial dysfunction, foam cell and advanced lesions formation as well as in myocardial ischemia. Furthermore, it is known that LOX-1 plays a pivotal role in mitochondrial DNA damage, vascular cell apoptosis, and autophagy. A large number of studies provide evidence of a LOX-1's role in endothelial dysfunction, hypertension, diabetes, and obesity. In addition, novel insights into LOX-1 ligands and the activated signaling pathways have been gained. Recent studies have shown an interaction of LOX-1 with microRNA's, thus providing novel tools to regulate LOX-1 function. Because LOX-1 is increased in atherosclerotic plaques and contributes to endothelial dysfunction, several compounds were tested in vivo and in vitro to modulate the LOX-1 expression in therapeutic approaches.

Advanced Maternal Age Worsens Postpartum Vascular Function

The age at which women experience their first pregnancy has increased throughout the decades. Pregnancy has an important influence on maternal short- and long-term cardiovascular outcomes. Pregnancy at an advanced maternal age increases maternal risk of gestational diabetes, preeclampsia, placenta previa and caesarian delivery; complications which predict worsened cardiovascular health in later years. Aging also independently increases the risk of cardiovascular disease; therefore, combined risk in women of advanced maternal age may lead to detrimental cardiovascular outcomes later in life. We hypothesized that pregnancy at an advanced maternal age would lead to postpartum vascular dysfunction. We used a reproductively aged rat model to investigate vascular function in never pregnant (virgin), previously pregnant (postpartum) and previously mated but never delivered (nulliparous) rats at approximately 13.5 months of age (3 months postpartum or equivalent). Nulliparous rats, in which pregnancy was spontaneously lost, demonstrated significantly reduced aortic relaxation responses (methylcholine [MCh] Emax: 54.2 ± 12.6%) vs. virgin and postpartum rats (MCh Emax: 84.8 ± 3.5% and 84.7 ± 3.2% respectively); suggesting pregnancy loss causes a worsened vascular pathology. Oxidized LDL reduced relaxation to MCh in aorta from virgin and postpartum, but not nulliparous rats, with an increased contribution of the LOX-1 receptor in the postpartum group. Further, in mesenteric arteries from postpartum rats, endothelium-derived hyperpolarization (EDH)-mediated vasodilation was reduced and a constrictive prostaglandin effect was apparent. In conclusion, aged postpartum rats exhibited vascular dysfunction, while rats which had pregnancy loss demonstrated a distinct vascular pathology. These data demonstrate mechanisms which may lead to worsened outcomes at an advanced maternal age; including early pregnancy loss and later life cardiovascular dysfunction.

The role of the lectin-like oxLDL receptor (LOX-1) in traffic-generated air pollution exposure-mediated alteration of the brain microvasculature in Apolipoprotein (Apo) E knockout mice

Recent studies have shown a strong correlation between air pollution-exposure and detrimental outcomes in the central nervous system, including alterations in blood brain barrier (BBB) integrity, neuroinflammation, and neurodegeneration. However, the mechanisms mediating these pathologies have not yet been fully elucidated. We have previously reported that exposure to traffic-generated air pollution results in increased circulating oxidized low-density lipoprotein (oxLDL), associated with alterations in BBB integrity, in atherosclerotic Apolipoprotein E null (ApoE-/-) mice. Thus, we investigated the role of the lectin-like oxLDL receptor (LOX)-1 in mediating these deleterious effects in ApoE-/- mice exposed to a mixture of gasoline and diesel engine exhaust (MVE: 100 PM µg/m3) for 6 h/d, 7d/week, for 30 d by inhalation. Concurrent with exposures, a subset of mice were treated with neutralizing antibodies to LOX-1 (LOX-1 Ab) i.p., or IgG (control) i.p., every other day during exposures. Resulting brain microvascular integrity, tight junction (TJ) protein expression, matrix metalloproteinase (MMP)-9/-2 activity, ROS, and markers of cellular adhesion and monocyte/macrophage sequestration were assessed. MVE-exposure resulted in decreased BBB integrity and alterations in microvascular TJ protein expression, associated with increased LOX-1 expression, MMP-9/-2 activities, and lipid peroxidation, each of which was attenuated with LOX-1 Ab treatment. Furthermore, MVE-exposure induced cerebral microvascular ROS and adhesion molecules, expression of which was not normalized through LOX-1 Ab-treatment. Such findings suggest that alterations in brain microvascular structure and integrity observed with MVE-exposure may be mediated, at least in part, via LOX-1 signaling.

Soluble lectin-like oxidized low-density lipoprotein receptor-1 as a novel biomarker for large-artery atherosclerotic stroke

BACKGROUND

Serum soluble lectin-like oxidized low-density lipoprotein receptor-1 (sLOX-1) has been shown associated with the progression of atherosclerosis in endothelial cells. We sought to assess whether the baseline serum sLOX-1 levels are correlated with the presence and short-term functional outcome of large-artery atherosclerotic (LAA) stroke.

METHODS

The study recruited 241 subjects, including 148 consecutive patients with acute ischemic stroke with the subtype of LAA and 93 non-stroke controls. Clinical and laboratory data, including serum concentration of sLOX-1, were collected within 24 h of admission, and the severity of LAA stroke patients was evaluated by National Institutes of Health Stroke Scale score. And functional outcome was assessed by modified Rankin Scale three months after stroke. The association between sLOX-1 level and the functional outcome at three months was analyzed by multiple logistic regression models.

RESULTS

Serum levels of sLOX-1 in the LAA stroke patients were significantly higher as compared to normal controls (2.48 ± 0.93 ng/ml vs. 2.22 ± 0.79 ng/ml in the controls, t = 2.301, p = 0.022). The levels of serum sLOX-1 in patients with good outcome were significantly lower than those with poor outcome (2.39 ± 0.94 ng/ml vs. 2.77 ± 0.84 ng/ml, p = 0.032). After adjusting for potential confounders, sLOX-1 was still an independent predictor for the function outcome with an adjusted OR of 3.39 (95% CI, 1.61-7.11, p = 0.001).

CONCLUSIONS

The serum sLOX-1 level was higher in patients with LAA stroke, and it was an independent predictor of functional outcome in patients with LAA ischemic stroke.

Association of the LOX-1 rs1050283 Polymorphism with Risk for Atherosclerotic Cerebral Infarction and its Effect on sLOX-1 and LOX-1 Expression in a Chinese Population

AIMS

The interaction between lectin-like oxidized low density lipoprotein (LDL) receptor-1 (LOX-1) and oxidized LDL (ox-LDL) has been viewed as an important pathogenic factor for cardiovascular diseases. This study aimed to explore the association of a functional polymorphism rs1050283 in the 3'-untranslated region of the LOX-1 gene with atherosclerotic cerebral infarction (ACI) susceptibility, and we also investigated the effects of the rs1050283 polymorphism on LOX-1 expression and serum levels of sLOX-1 in patients with ACI.

METHODS

A case-controlled study was performed in 526 patients with ACI and 640 healthy controls. Genotyping was performed by DNA sequencing method. Real-time PCR and Western blotting were used to determine the level of LOX-1 expression. Serum levels of sLOX-1 were quantified using ELISA according to the manufacturer's instruction.

RESULTS

The results of the present study showed that the frequency of rs1050283 T allele was significantly higher in patients with ACI than in healthy controls. We also found that the rs1050283 polymorphism T allele was associated with increased LOX-1 expression at mRNA and protein levels in patients with ACI. Furthermore, we also observed that among patients with ACI, those with the rs1050283 T allele showed an increased serum level of sLOX-1.

CONCLUSION

Our research demonstrated that the rs1050283 T allele of LOX-1 is strongly associated with an increased risk for ACI in a Chinese population, which also affects levels of LOX-1 and sLOX-1.

Lectin-like oxidized low-density lipoprotein receptor (LOX-1) in sickle cell disease vasculopathy

Lectin-like oxidized low-density lipoprotein (LDL) receptor-1 (LOX-1) is an endothelial receptor for oxidized LDL. Increased expression of LOX-1 has been demonstrated in atherosclerotic lesions and diabetic vasculopathy. In this study, we investigate the expression of LOX-1 receptor in sickle cell disease (SCD) vasculopathy. Expression of LOX-1 in brain vascular endothelium is markedly increased and LOX-1 gene expression is upregulated in cultured human brain microvascular endothelial cells by incubation with SCD erythrocytes. Also, the level of circulating soluble LOX-1 concentration is elevated in the plasma of SCD patients. Increased LOX-1 expression in endothelial cells is potentially involved in the pathogenesis of SCD vasculopathy. Soluble LOX-1 concentration in SCD may provide a novel biomarker for risk stratification of sickle cell vascular complications.