Novel concepts in the genesis of hypertension: role of LOX-1

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.

The Effects of Statin Therapy on Oxidized LDL and Its Antibodies: A Systematic Review and Meta-Analysis

Background

Elevated serum low-density lipoproteins (LDL), the substrate for the formation of atherogenic oxidized LDLs (oxLDL), are a causal factor for atherosclerotic cardiovascular disease (ASCVD). Statins are well known to decrease LDL particle concentration and reduce ASCVD morbidity and mortality.

Objective

To perform a meta-analysis of the effects of statins (i.e., type, dose, and duration of treatment) on serum levels of oxLDL and on immunoglobulin M (IgM) and immunoglobulin G (IgG) antibody levels against oxLDL.

Methods

PubMed, Scopus, Embase, and Web of Science were searched up to February 5th, 2021, for randomized controlled trials (RCT) evaluating the effect of statins on oxLDL and anti-oxLDL antibody levels. Meta-analysis was performed using Comprehensive Meta-Analysis (CMA) V2 software. To evaluate the influence of each study on the overall effect size, a sensitivity analysis was performed using the leave-one-out method. Evaluation of the funnel plot, Begg's rank correlation, and Egger's weighted regression tests was used to assess the presence of publication bias in the meta-analysis.

Results

A total of 28 RCTs including 4019 subjects were finally included in the meta-analysis. The results indicated a significant decrease in circulating concentrations of oxLDL after treatment with statins (SMD: -2.150, 95% CI: -2.640, -1.697, p < 0.001). Subgroup analysis found no significant effect of the intensity of statin treatment or statin lipophilicity on the reduction of circulating concentrations of oxLDL. An additional meta-analysis of 3 trials showed that statins did not change the serum levels of IgM and IgG antibodies to oxLDL.

Conclusion

Statin therapy decreases serum oxLDL concentrations but does not affect circulating levels of anti-oxLDL antibodies.

Original contribution: sleeve gastrectomy reduces soluble lectin-like oxidized low-density lipoprotein receptor-1 (sLOX-1) levels in patients with morbid obesity

BACKGROUND

Early diagnosis of subclinical cardiovascular disease (CVD) in patients with morbid obesity is important. We investigated the effects of sleeve gastrectomy (SG) on serum soluble lectin-like oxidized low-density lipoprotein receptor-1 (sLOX-1), oxidized LDL (oxLDL), and other metabolic and inflammatory parameters associated with atherosclerosis in patients with morbid obesity.

METHODS

Body mass index (BMI) measurements and assays of metabolic and inflammatory markers were taken in patients in an SG surgery group and a healthy control group and compared at baseline and 12 months after SG. Correlations with changes in these parameters and variations in sLOX-1 were analyzed.

RESULTS

Metabolic and inflammatory marker values in the surgery (n = 20) and control (n = 20) groups were significantly different at baseline (p < 0.001). The majority of surgery group biomarker levels significantly decreased with mean BMI loss (- 11.8 ± 9.0, p < 0.001) at 12 months, trending toward control group values. Baseline albumin level as well as percentage reductions in oxLDL and the cholesterol retention fraction (CRF) were found to be significantly correlated with percentage reduction in sLOX-1 at 12 months following SG.

CONCLUSION

Metabolic and inflammatory biomarkers elevated at baseline significantly decreased after SG weight loss. Weight loss induced by SG may limit endothelial damage by reducing levels of oxLDL and LOX-1 as assessed by sLOX-1. These findings suggest that sLOX-1 may function as a marker of atherosclerotic disease states in patients with morbid obesity and that metabolic/bariatric surgery can play a meaningful role in CVD prevention.

Inhibition of the transient receptor potential vanilloid 3 channel attenuates carbon tetrachloride-induced hepatic fibrosis

Transient receptor potential vanilloid 3 (TRPV3) is a member of the TRP superfamily. Previous studies have demonstrated that TRPV3 is associated with myocardial fibrosis. However, the role of TRPV3 in hepatic fibrosis and its underlying mechanisms are still unclear. This study aimed to elucidate the underlying effects of TRPV3 on hepatic fibrosis at multiple biological levels. First, immunohistochemical staining was performed to examine TRPV3 expression in human hepatic cirrhosis tissues. Then, we established a CCl₄-induced hepatic fibrosis mouse model. The TRPV3 selective agonist drofenine and its inhibitor, forsythoside B, were intraperitoneally injected to investigate the relationship between TRPV3 and liver fibrosis progression. Finally, in vitro studies were performed using hepatic stellate cells (HSCs) to discover the potential molecular biological mechanisms. Immunohistochemistry revealed TRPV3 overexpression in liver cirrhosis. In the liver fibrosis groups, TRPV3 inhibitor treatment significantly reduced liver fibrosis, while TRPV3 agonist exacerbated its progression. In HSCs, knocking down TRPV3 with siRNA impaired DNA synthesis and cell proliferation and increased cell apoptosis. Furthermore, we found that knockdown of TRPV3 could reduce the lectin like oxidized lowdensity lipoprotein receptor-1 (LOX-1) protein levels. Our research suggests that lower expression or functional levels of TRPV3 can ameliorate the inflammatory response and fibrotic tissue proliferation.

Lipoxygenase Inhibitors as Cancer Chemopreventives: Discovery, Recent Developments and Future Perspectives

BACKGROUND

Leukotrienes (LTs) constitute a bioactive group of Polyunsaturated Fatty Acid (PUFA) metabolites molded by the enzymatic activity of lipoxygenase (LO) and have a pivotal role in inflammation and allergy. Evidence is accumulating both by in vitro cell culture experiments and animal tumor model studies in support of the direct involvement of aberrant metabolism of arachidonic acid (ACD) in the development of several types of human cancers such as lung, prostate, pancreatic and colorectal malignancies. Several independent experimental data suggest a correlation between tumoral cells viability and LO gene expression, especially, 5-lipoxygenase (5-LO). Overexpressed 5-LO cells live longer, proliferate faster, invade more effectively through extracellular matrix destruction and activate the anti-apoptotic signaling mechanisms more intensively compared to the normal counterparts. Thus, some groups of lipoxygenase inhibitors may be effective as promising chemopreventive agents.

METHODS

A structured search of bibliographic databases for peer-reviewed research literature regarding the role of LO in the pathogenesis of cancer was performed. The characteristics of screened papers were summarized and the latest advances focused on the discovery of new LO inhibitors as anticancer agents were discussed.

RESULTS

More than 180 papers were included and summarized in this review; the majority was about the newly designed and synthesized 5-LO inhibitors as anti-inflammatory and anticancer agents. The enzyme's structure, 5-LO pathway, 5-LO inhibitors structure-activity relationships as well as the correlation between these drugs and a number of most prevalent human cancers were described. In most cases, it has been emphasized that dual cyclooxygenase-2/5-lipoxygenase (COX-2/5-LO) or dual 5-lipoxygenase/microsomal prostaglandin E synthase-1 (5-LO/mPGES-1) inhibitors possess considerable inhibitory activities against their target enzymes as well as potent antiproliferative effects. Several papers disclosing 5-lipoxygenase activating protein (FLAP) antagonists as a new group of 5-LO activity regulators are also subject to this review. Also, the potential of 12-lipoxygenase (12- LO) and 15-lipoxygenase (15-LO) inhibitors as chemopreventive agents was outlined to expand the scope of new anticancer agents discovery. Some peptides and peptidomimetics with anti-LT activities were described as well. In addition, the cytotoxic effects of lipoxygenase inhibitors and their adverse effects were discussed and some novel series of natural-product-derived inhibitors of LO was also discussed in this review.

CONCLUSION

This review gives insights into the novel lipoxygenase inhibitors with anticancer activity as well as the different molecular pharmacological strategies to inhibit the enzyme effectively. The findings confirm that certain groups of LO inhibitors could act as promising chemopreventive agents.

Metabolic and Vascular Effect of the Mediterranean Diet

Several studies indicated how dietary patterns that were obtained from nutritional cluster analysis can predict disease risk or mortality. Low-grade chronic inflammation represents a background pathogenetic mechanism linking metabolic risk factors to increased risk of chronic degenerative diseases. A Mediterranean diet (MeDi) style has been reported as associated with a lower degree of inflammation biomarkers and with a protective role on cardiovascular and cerebrovascular events. There is heterogeneity in defining the MedDiet, and it can, owing to its complexity, be considered as an exposome with thousands of nutrients and phytochemicals. Recently, it has been reported a novel positive association between baseline plasma ceramide concentrations and cardiovascular events and how adherence to a Mediterranean Diet-style may influence the potential negative relationship between elevated plasma ceramide concentrations and cardiovascular diseases (CVD). Several randomized controlled trials (RCTs) showed the positive effects of the MeDi diet style on several cardiovascular risk factors, such as body mass index, waist circumference, blood lipids, blood pressure, inflammatory markers and adhesion molecules, and diabetes and how these advantages of the MeDi are maintained in comparison of a low-fat diet. Some studies reported a positive effect of adherence to a Mediterranean Diet and heart failure incidence, whereas some recent studies, such as the PREDIMED study, showed that the incidence of major cardiovascular events was lower among those assigned to MeDi supplemented with extra-virgin olive oil or nuts than among those assigned to a reduced-fat diet. New studies are needed to better understand the molecular mechanisms, whereby the MedDiet may exercise its effects. Here, we present recent advances in understanding the molecular basis of MedDiet effects, mainly focusing on cardiovascular diseases, but also discussing other related diseases. We review MedDiet composition and assessment as well as the latest advances in the genomic, epigenomic (DNA methylation, histone modifications, microRNAs, and other emerging regulators), transcriptomic (selected genes and whole transcriptome), and metabolomic and metagenomic aspects of the MedDiet effects (as a whole and for its most typical food components). We also present a review of the clinical effects of this dietary style underlying the biochemical and molecular effects of the Mediterranean diet. Our purpose is to review the main features of the Mediterranean diet in particular its benefits on human health, underling the anti-inflammatory, anti-oxidant and anti-atherosclerotic effects to which new knowledge about epigenetic and gut-microbiota relationship is recently added.

Hypertensive disorders during pregnancy and 3 years after delivery in women with gestational hyperglycemia

AIMS

Women with gestational hyperglycemia commonly experience hypertensive disorders during pregnancy. More information is needed about how hypertension develops in these patients over time. We investigated the prevalence of hypertension during and 3 years after pregnancy in Caucasian women with gestational hyperglycemia. We also investigated metabolic syndrome presence, glucose tolerance status, insulin sensitivity and insulin secretion levels in the follow-up period.

METHODS

In a prospective longitudinal study with a 3-year follow-up, we assessed hypertension status and clinical-related characteristics of 103 consecutive women with gestational hyperglycemia sub-grouped according to their hypertensive status during and after pregnancy.

RESULTS

Overall, 29 (28.1%) women had hypertension during pregnancy (24 gestational hypertension; 4 chronic hypertension; 1 preeclampsia). At follow-up 16 (15.5%) women were diagnosed as having hypertension (11 with hypertension in pregnancy; 5 with a normotensive pregnancy). Women with hypertension after pregnancy had higher BMI, metabolic syndrome rate and worse insulin resistance indexes than normotensive women. Weight increase at follow-up (OR 1.17, 95% CI 1.00-1.35) and hypertension in pregnancy (OR 6.72, 95% CI 1.17-38.64) were associated with hypertension after pregnancy.

CONCLUSIONS

Women with gestational hyperglycemia should undergo regular monitoring during and after pregnancy to detect metabolic and clinical impairments and to prevent cardiovascular harm.

Osteopontin deficiency reduces kidney damage from hypercholesterolemia in Apolipoprotein E-deficient mice

Hypercholesterolemia is a well-established risk factor for kidney injury, which can lead to chronic kidney disease (CKD). Osteopontin (OPN) has been implicated in the pathology of several renal conditions. This study was to evaluate the effects of OPN on hypercholesterolemia induced renal dysfunction. Eight-week-old male mice were divided into 4 groups: apolipoprotein E knockout (ApoE^−/−) and ApoE/OPN knockout (ApoE^−/−/OPN^−/−) mice fed a normal diet (ND) or high cholesterol diet (HD). After 4 weeks, Periodic acid-Schiff (PAS) and oil red O staining revealed excessive lipid deposition in the glomeruli of ApoE^−/−HD mice, however, significantly suppressed in ApoE^−/−/OPN^−/−HD mice. Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) expression was lower in the glomeruli of ApoE^−/−/OPN^−/−HD mice than ApoE^−/−HD mice. In vitro study, primary mesangial cells were incubated with recombinant mouse OPN (rmOPN). RmOPN induced LOX-1 mRNA and protein expression in primary mesangial cells. Pre-treatment with an ERK inhibitor suppressed the LOX-1 gene expression induced by rmOPN. These results indicate that OPN contributes to kidney damage in hypercholesterolemia and suggest that inhibition of OPN may provide a potential therapeutic target for the prevention of hypercholesterolemia.

Inter-relations between osteoarthritis and metabolic syndrome: A common link?

Osteoarthritis (OA) is a degenerative disorder of the joint, principally occurring during aging, and characterized by a focal degradation of cartilage. It is the most prevalent rheumatic disease in industrialized countries and represents the second cause of disability in France. However, the etiology of OA remains unclear. There is only one cell type found in cartilage, chondrocyte, which is responsible for its repair and the synthesis of the elements of the extra-cellular matrix. A dysfunction of these cells results in an imbalance between repair and degradation in cartilage, leading to its destruction. Recently, a link between OA and metabolic syndrome (MetS) has been suggested, introducing a notion of metabolic OA, and a new vision of the disease. MetS is characterized by a cluster of factors (insulin resistance, hypertension, dyslipidemia, visceral obesity), although there is still no clear definition of it. During the 20th century, MetS dramatically increased with changes in population lifestyle, becoming a major health issue in industrialized countries. MetS concerns 10-30% of the worldwide population, but is prevalent in 59% of OA patients. Patients with both OA and MetS have more severe symptoms, occurring sooner than in the general population. Indeed, OA is generally a disease concerning the population over 65 years old, but with an associated MetS the target population is around 50 years old. In this review, we will focus on common factors in OA and MetS, such as hypertension, obesity, dyslipidemia, mitochondrial dysfunction and hyperglycemia, linking one disease to the other.

Effect of olive oil phenolic compounds on the expression of blood pressure-related genes in healthy individuals

PURPOSE

To investigate whether the ingestion of olive oil having different phenolic contents influences the expression of blood pressure-related genes, involved in the renin-angiotensin-aldosterone system, in healthy humans.

METHODS

A randomized, double-blind, crossover human trial with 18 healthy subjects, who ingested 25 mL/day of olive oils (1) high (366 mg/kg, HPC) and (2) low (2.7 mg/kg, LPC) in phenolic compounds for 3 weeks, preceded by 2-week washout periods. Determination of selected blood pressure-related gene expression in peripheral blood mononuclear cells (PBMNC) by qPCR, blood pressure and systemic biomarkers.

RESULTS

HPC decreased systolic blood pressure compared to pre-intervention values and to LPC, and maintained diastolic blood pressure values compared to LPC. HPC decreased ACE and NR1H2 gene expressions compared with pre-intervention values, and IL8RA gene expression compared with LPC.

CONCLUSIONS

The introduction to the diet of an extra-virgin olive oil rich in phenolic compounds modulates the expression of some of the genes related to the renin-angiotensin-aldosterone system. These changes could underlie the decrease in systolic blood pressure observed.

Q192R Paraoxonase (PON)1 Polymorphism, Insulin Sensitivity, and Endothelial Function in Essential Hypertensive Men

AIMS

Essential hypertension is characterized by increased reactive oxygen species (ROS) generation harmful for insulin sensitivity and nitric oxide (NO)-mediated vasomotor function, a noxious effect that paraoxonase (PON)1, an antioxidant circulating high-density lipoprotein (HDL)-bound esterase, may counteract. The PON1 gene contains several polymorphisms including a glutamine (Q) to arginine (R) transition at position 192 encoding circulating allozymes with higher antioxidant activity that might influence both parameters.

METHODS

Q192R was determined by polymerase chain reaction in 72 never-treated, glucose-tolerant, uncomplicated essential hypertensive men. Insulin sensitivity was assessed by homeostasis model assessment (HOMA) and endothelial function by forearm vasodilation (strain-gage venous plethysmography) to intra-arterial acetylcholine (ACH) with sodium nitroprusside (NIP) as a NO-independent control. Additional evaluation variables included 24-hour blood pressure (BP), lipids, BMI, smoking status, and metabolic syndrome (MetS) by Adult Treatment Panel (ATP)-III criteria. R192 was considered as the rare allele, and its associations analyzed by dominant models (Q/Q vs. Q/R + R/R).

RESULTS

Genotype frequencies were consistent with the Hardy–Weinberg equilibrium. HOMA was lower and insulin resistance (the upper fourth of HOMA values distribution) less prevalent in Q/R + R/R carriers in whom ACH-mediated vasodilatation was greater and endothelial dysfunction (the bottom fourth of ACH^AUC values distribution) less frequent than in Q/Q homozygotes. Q192R polymorphism and MetS were unrelated parameters despite their common association with insulin resistance. 24-hour BP, BMI, lipids, and smoking habits were homogeneously distributed across genotypes.

CONCLUSIONS

Q192R polymorphism associates differentially with insulin sensitivity and endothelial function in essential hypertensive men.

Lectin-like oxidized low-density lipoprotein receptor 1 pathways

BACKGROUND

The role of lectin-like oxidized low-density lipoprotein receptor (LOX)-1 has been implicated in the pathogenesis of different diseases, including atherosclerosis, hypertension, obesity, diabetes mellitus and metabolic syndrome. To date, several studies aimed at partially investigating the mechanistic role of LOX-1 in these various pathologies. Still, so far, the precise signal transduction pathways involving LOX-1 have not yet been elucidated.

MATERIALS AND METHODS

The most recent data published by the authors as well as others concerning different pathways involving LOX-1 are collected to formulate the presented updated review.

RESULTS

One of the most prominent pathways highlighted in the present review is the relationship of LOX-1 to NADPH oxidase that acts as a major source of harmful free radicals causing oxidative stress in blood vessels. Other pathways involve lipid and glucose metabolism-mediated signal transduction.

DISCUSSION

The modulatory role of LOX-1 on nitric oxide and renin/angiotensin systems as well as on fibrosis, apoptosis and inflammatory pathways is discussed.

CONCLUSION

The current review revisits LOX-1 and its related pathways, implicating LOX-1 as a target for ameliorating various pathological conditions.

Activation of renin-angiotensin system is involved in dyslipidemia-mediated renal injuries in apolipoprotein E knockout mice and HK-2 cells

Background

Dyslipidemia and activation of renin-angiotensin system (RAS) contribute to the progression of chronic kidney disease (CKD). This study investigated possible synergistic effects of intrarenal RAS activation with hyperlipidemia in renal injuries.

Methods

Apolipoprotein knockout mice were fed with normal chow diet (control) or high fat diet (HF group) for eight weeks. Human proximal tubular epithelial cell line (HK-2) was treated without (control) or with cholesterol (30 μg/ml) plus 25-hydroxycholesterol (1 μg/ml) (lipid group) for 24 hours. The plasma lipid profile and RAS components were determined by clinical biochemistry assay and radiommunoassay, respectively. Collagen deposition in kidneys was evaluated by Masson-staining. The gene and protein expressions of molecules involved in RAS components and biomarkers of epithelial mesenchymal transition (EMT) were examined by real-time PCR, immunochemical staining, and Western blot.

Results

The mice fed with high-fat diet showed significant hyperlipidemia with collagen deposition in renal tubular interstitium compared to controls. The plasma levels of renin, angiotensin I, and angiotensin II were no difference in two groups. However, the kidneys of HF group showed up-regulated RAS components, which were positively associated with increased plasma levels of triglyceride, total cholesterol, and LDL. These effects were further confirmed by in vitro studies. Lipid loading induced HK-2 cells underwent EMT, which was closely associated with the increased expressions of intracellular RAS components.

Conclusions

Local RAS activation was involved in hyperlipidemia-mediated renal injuries, suggesting that there are synergistic effects resulting from RAS activation with hyperlipidemia that accelerates the progression of CKD.

Redox-inflammatory synergy in the metabolic syndrome

Metabolic syndrome (MetS) comprises interrelated disease states including obesity, insulin resistance and type 2 diabetes (T2DM), dyslipidemia, and hypertension. Essential to normal physiological function, and yet massively damaging in excess, oxidative stress and inflammation are pivotal common threads among the pathologies of MetS. Increasing evidence indicates that redox and inflammatory dysregulation parallels the syndrome's physiological, biochemical, and anthropometric features, leading many to consider the pro-oxidative, pro-inflammatory milieu an unofficial criterion in itself. Left unchecked, cross-promotion of oxidative stress and inflammation creates a feed-forward cycle that can initiate and advance disease progression. Such redox-inflammatory integration is evident in the pathogenesis of obesity, insulin resistance and T2DM, atherogenic dyslipidemia, and hypertension, and is thus hypothesized to be the "common soil" from which they develop. The present review highlights the synergistic contributions of redox-inflammatory processes to each of the components of the MetS.

Olive oil polyphenols decrease blood pressure and improve endothelial function in young women with mild hypertension

BACKGROUND

Olive oil polyphenols have been associated with several cardiovascular health benefits. This study aims to examine the influence of a polyphenol-rich olive oil on blood pressure (BP) and endothelial function in 24 young women with high-normal BP or stage 1 essential hypertension.

METHODS

We conducted a double-blind, randomized, crossover dietary-intervention study. After a run-in period of 4 months (baseline values), two diets were used, one with polyphenol-rich olive oil (∼30 mg/day), the other with polyphenol-free olive oil. Each dietary period lasted 2 months with a 4-week washout between diets. Systolic and diastolic BP, serum or plasma biomarkers of endothelial function, oxidative stress, and inflammation, and ischemia-induced hyperemia in the forearm were measured.

RESULTS

When compared to baseline values, only the polyphenol-rich olive oil diet led to a significant (P < 0.01) decrease of 7.91 mm Hg in systolic and 6.65 mm Hg of diastolic BP. A similar finding was found for serum asymmetric dimethylarginine (ADMA) (-0.09 ± 0.01 µmol/l, P < 0.01), oxidized low-density lipoprotein (ox-LDL) (-28.2 ± 28.5 µg/l, P < 0.01), and plasma C-reactive protein (CRP) (-1.9 ± 1.3 mg/l, P < 0.001). The polyphenol-rich olive oil diet also elicited an increase in plasma nitrites/nitrates (+4.7 ± 6.6 µmol/l, P < 0.001) and hyperemic area after ischemia (+345 ± 386 perfusion units (PU)/sec, P < 0.001).

CONCLUSIONS

We concluded that the consumption of a diet containing polyphenol-rich olive oil can decrease BP and improve endothelial function in young women with high-normal BP or stage 1 essential hypertension.

Simvastatin inhibits the additive activation of ERK1/2 and proliferation of rat vascular smooth muscle cells induced by combined mechanical stress and oxLDL through LOX-1 pathway

Vein grafts interposed into arteries are susceptible to the development of atherosclerosis due to rapid increases in blood pressure. This process is accelerated in patients with hyperlipidemia. The molecular mechanism underlying this process is unknown. In this study, quiescent rat vascular smooth muscle cells (VSMCs) were treated in vitro with mechanical stretch stress (10% elongation) with and without oxLDL (25 μg/ml) in the presence and absence of simvastatin (2.5 μmol/L). The results demonstrate that stretch stress and oxLDL can each induce activation of ERK1/2 and Ki-67 expression in VSMCs, but the peak levels of ERK activation and Ki-67 expression were observed in groups subjected to both stretch stress and oxLDL. Simvastatin was found to inhibit increased ERK activation and Ki-67 expression in VSMCs subjected to stretch stress with or without oxLDL. Mechanically, simvastatin was also found to inhibit increased expression of LOX-1 (a receptor of oxLDL) in VSMCs subjected to stretch stress with or without oxLDL. Knockdown of LOX-1 via small interfering RNAs (siRNA-LOX-1) resulted in obvious inhibition of ERK activation in VSMCs subjected to stretch stress with and without oxLDL. These results suggest that combined stretch stress and oxLDL can additively promote the activation of ERK1/2 leading to accelerated proliferation of VSMCs (e.g. increased Ki-67 expression) via LOX-1 signal pathway. This was found to be partially inhibited by simvastatin. These results may provide important data for the treatment and prevention of hypertension with or without hyperlipidemia.