Pitavastatin attenuates the PDGF-induced LR11/uPA receptor-mediated migration of smooth muscle cells

A heparin-rosuvastatin-loaded P(LLA-CL) nanofiber-covered stent inhibits inflammatory smooth-muscle cell viability to reduce in-stent stenosis and thrombosis

Background

An endovascular covered-stent has unique advantages in treating complex intracranial aneurysms; however, in-stent stenosis and late thrombosis have become the main factors affecting the efficacy of covered-stent treatment. Smooth-muscle-cell phenotypic modulation plays an important role in late in-stent stenosis and thrombosis. Here, we determined the efficacy of using covered stents loaded with drugs to inhibit smooth-muscle-cell phenotypic modulation and potentially lower the incidence of long-term complications.

Methods

Nanofiber-covered stents were prepared using coaxial electrospinning, with the core solution prepared with 15% heparin and 20 µM rosuvastatin solution (400: 100 µL), and the shell solution prepared with 120 mg/mL hexafluoroisopropanol. We established a rabbit carotid-artery aneurysm model, which was treated with covered stents. Angiography and histology were performed to evaluate the therapeutic efficacy and incidence rate of in-stent stenosis and thrombosis. Phenotype, function, and inflammatory factors of smooth-muscle cells were studied to explore the mechanism of rosuvastatin action in smooth-muscle cells.

Result

Heparin–rosuvastatin-loaded nanofiber scaffold mats inhibited the proliferation of synthetic smooth-muscle cells, and the nanofiber-covered stent effectively treated aneurysms in the absence of notable in-stent stenosis. Additionally, in vitro experiments showed that rosuvastatin inhibited the smooth-muscle-cell phenotypic modulation of platelet-derived growth factor-BB induction and decreased synthetic smooth-muscle-cell viability, as well as secretion of inflammatory cytokines.

Conclusion

Rosuvastatin inhibited the abnormal proliferation of synthetic smooth-muscle cells, and heparin–rosuvastatin-loaded covered stents reduced the incidence of stenosis and late thrombosis, thereby improving the healing rates of stents used for aneurysm treatment.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-00867-8.

Soluble SORLA Enhances Neurite Outgrowth and Regeneration through Activation of the EGF Receptor/ERK Signaling Axis

SORLA is a transmembrane trafficking protein associated with Alzheimer's disease risk. Although SORLA is abundantly expressed in neurons, physiological roles for SORLA remain unclear. Here, we show that cultured transgenic neurons overexpressing SORLA feature longer neurites, and accelerated neurite regeneration with wounding. Enhanced release of a soluble form of SORLA (sSORLA) is observed in transgenic mouse neurons overexpressing human SORLA, while purified sSORLA promotes neurite extension and regeneration. Phosphoproteomic analyses demonstrate enrichment of phosphoproteins related to the epidermal growth factor (EGFR)/ERK pathway in SORLA transgenic mouse hippocampus from both genders. sSORLA coprecipitates with EGFR in vitro, and sSORLA treatment increases EGFR Y1173 phosphorylation, which is involved in ERK activation in cultured neurons. Furthermore, sSORLA triggers ERK activation, whereas pharmacological EGFR or ERK inhibition reverses sSORLA-dependent enhancement of neurite outgrowth. In search for downstream ERK effectors activated by sSORLA, we identified upregulation of Fos expression in hippocampus from male mice overexpressing SORLA by RNAseq analysis. We also found that Fos is upregulated and translocates to the nucleus in an ERK-dependent manner in neurons treated with sSORLA. Together, these results demonstrate that sSORLA is an EGFR-interacting protein that activates EGFR/ERK/Fos signaling to enhance neurite outgrowth and regeneration.SIGNIFICANCE STATEMENT SORLA is a transmembrane trafficking protein previously known to reduce the levels of amyloid-β, which is critical in the pathogenesis of Alzheimer's disease. In addition, SORLA mutations are a risk factor for Alzheimer's disease. Interestingly, the SORLA ectodomain is cleaved into a soluble form, sSORLA, which has been shown to regulate cytoskeletal signaling pathways and cell motility in cells outside the nervous system. We show here that sSORLA binds and activates the EGF receptor to induce downstream signaling through the ERK serine/threonine kinase and the Fos transcription factor, thereby enhancing neurite outgrowth. These findings reveal a novel role for sSORLA in promoting neurite regeneration through the EGF receptor/ERK/Fos pathway, thereby demonstrating a potential neuroprotective mechanism involving SORLA.

Translating the effects of statins: from redox regulation to suppression of vascular wall inflammation

Vascular oxidative stress is a key feature of atherogenesis, and targeting vascular redox signalling is a rational therapeutic goal in vascular disease pathogenesis. 3-hydroxy-3-methyl-glutaryl-CoA reductase inhibitors or statins are potent lipid-lowering drugs that improve cardiovascular outcomes. It is now widely accepted that cardiovascular disease prevention by statins is dependent not only on their lipid lowering effects, but also on their beneficial effects on vascular redox signalling. Cell culture and animal models have provided important findings on the effects of statins on vascular redox and nitric oxide bioavailability. Recent evidence from studies on human vessels has further enhanced our understanding of the "pleiotropic" effects of statins on vascular wall. Reversal of endothelial dysfunction in human vessels by statins is dependent on the mevalonate pathway and Rac1 inhibition. These critical steps are responsible for reducing NADPH-oxidase activity and improving tetrahydrobiopterin bioavailability and nitric oxide synthase (NOS) coupling in human vessels. However, mevalonate pathway inhibition has been also held responsible for some of the side effects observed after statin treatment. In this review we summarise the existing knowledge on the effects of statins on vascular biology by discussing key findings from basic science as well as recent evidence from translational studies in humans. Finally, we discuss emerging aspects of statin pleiotropy, such as their effects on adipose tissue biology and adipokine synthesis that may light additional mechanistic links between statin treatment and improvement of clinical outcome in primary and secondary prevention.

Soluble LR11 is a novel biomarker for vascular lesions late after Kawasaki disease

OBJECTIVE

Coronary artery lesions (CALs) and a risk for early onset of atherosclerosis are major concerns following Kawasaki disease (KD). Intimal smooth muscle cells (SMCs) have an important role in vascular lesions in KD. It is known that soluble LR11 (sLR11) is a novel biomarker for vascular lesions and LR11 is markedly expressed in intimal SMCs in atherosclerotic lesions. In this study, we hypothesized that sLR11 reflects the presence of vascular lesions late after KD.

METHODS

Twenty-three age-matched controls (group 1) and 59 patients with a history of KD were enrolled; 36 with KD had normal coronary arteries or regressed aneurysms (group 2), and 23 had CALs (group 3).

RESULTS

Serum sLR11 levels in group 3 (median, interquartile range (IQR): 11.1 ng/mL, 9.3-13.9 ng/mL) were significantly higher than those in groups 1 (8.4 ng/mL, 7.1-10.2 ng/mL, p < 0.001) and 2 (9.0 ng/mL, 7.7-10.1 ng/mL, p < 0.01). Levels of sLR11 were positively correlated with levels of high-sensitivity C-reactive protein (r = 0.480, p < 0.01) and lipoprotein (a) (r = 0.486, p < 0.01).

CONCLUSION

These findings suggest that sLR11 reflects the development of vascular lesions in patients with serious CALs.

Prognostic impact of circulating soluble LR11 on long-term clinical outcomes in patients with coronary artery disease

BACKGROUND

LR11, a member of LDL receptor family, is a novel marker of the proliferation of intimal smooth muscle cells (SMCs). LR11 is released in soluble form (sLR11) by proteolytic shedding and has biological activity toward SMC migration. We previously showed that circulating sLR11 positively correlates with carotid intima-medial thickness (IMT) independently of classical atherosclerotic risk factors and that it significantly associates with the severity of CAD. However, the association between sLR11 and long-term clinical outcomes remain uncertain.

METHODS AND RESULTS

This study included 438 consecutive patients (mean age, 65.8 ± 9.6 y; male, 82.4%) who underwent coronary intervention between March 2003 and December 2004 at our institution. The patients were assigned to quartiles according to pre-procedural sLR11 values. The primary endpoints were composite cardiovascular disease (CVD) endpoints including cardiovascular death, non-fatal acute coronary syndrome and non-fatal stroke. During median follow-up of 2876 days, composite CVD endpoints occurred 97 (22.1%) patients including 41 (9.4%) with cardiovascular disease (CVD)-related death, 36 (8.2%) non-fatal ACS and 20 (4.6%) non-fatal strokes. The hazard ratio (HR) for composite CVD endpoints significantly and dose-dependently increased with sLR11 levels (p for trend = 0.0077). A higher logarithm-transformed sLR11 value was associated with a greater risk of composite CVD endpoints, and the increased number of adverse long-term clinical outcomes persisted even after adjustment for other independent variables (HR 1.87 95%CI 1.02-3.31, p = 0.0435).

CONCLUSIONS

Elevated sLR11 levels were significantly associated with higher long-term adverse cardiac events in patients with CAD. Further extensive studies are expected to elucidate the mechanistic role of sLR11 and its clinical value as a prognostic marker in the development of atherosclerosis.

Statins meditate anti-atherosclerotic action in smooth muscle cells by peroxisome proliferator-activated receptor-γ activation

The peroxisome proliferator-activated receptor-γ (PPARγ) is an important regulator of lipid and glucose metabolism, and its activation is reported to suppress the progression of atherosclerosis. We have reported that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) activate PPARγ in macrophages. However, it is not yet known whether statins activate PPARγ in other vascular cells. In the present study, we investigated whether statins activate PPARγ in smooth muscle cells (SMCs) and endothelial cells (ECs) and thus mediate anti-atherosclerotic effects. Human aortic SMCs (HASMCs) and human umbilical vein ECs (HUVECs) were used in this study. Fluvastatin and pitavastatin activated PPARγ in HASMCs, but not in HUVECs. Statins induced cyclooxygenase-2 (COX-2) expression in HASMCs, but not in HUVECs. Moreover, treatment with COX-2-siRNA abrogated statin-mediated PPARγ activation in HASMCs. Statins suppressed migration and proliferation of HASMCs, and inhibited lipopolysaccharide-induced expression of monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-α (TNF-α) in HASMCs. These effects of statins were abrogated by treatment with PPARγ-siRNA. Treatment with statins suppressed atherosclerotic lesion formation in Apoe(-/-) mice. In addition, transcriptional activity of PPARγ and CD36 expression were increased, and the expression of MCP-1 and TNF-α was decreased, in the aorta of statin-treated Apoe(-/-) mice. In conclusion, statins mediate anti-atherogenic effects through PPARγ activation in SMCs. These effects of statins on SMCs may be beneficial for the prevention of atherosclerosis.

Circulating soluble LR11, a novel marker of smooth muscle cell proliferation, is enhanced after coronary stenting in response to vascular injury

OBJECTIVE

Restenosis after vascular intervention remains a major clinical problem. Circulating LR11 has been shown a novel marker of intimal smooth muscle cell (SMC) proliferation in human and animal studies. The present study was performed to clarify the clinical significance of circulating LR11 in patients with stable angina pectoris after coronary stenting.

METHODS AND RESULTS

We firstly investigated the circulating sLR11 levels for 28 days after arterial injury in mice, and then assessed time-dependent change in circulating sLR11 level after coronary stenting in a clinical study. Mouse sLR11 levels rapidly increased to 4.0-fold of the control value without cuff placement at postoperative day (POD) 14, and the levels gradually declined to 3.1-fold of the control value until POD 28 in mice. The circulating soluble LR11 levels were measured (before and at 14, 60 and 240 days after coronary stenting in a clinical study of 102 consecutive patients with stable angina pectoris who were treated with percutaneous coronary intervention. Circulating sLR11 levels were significantly increased on days 14 and 60 after the procedure and positively associated with the angiographic late loss index.

CONCLUSIONS

Our study suggested that circulating sLR11 levels may be a potential marker for angiographic late loss in patients after coronary stenting. Further mechanistic studies are expected to know the clinical significance of sLR11 as a novel marker for intimal SMC.

Innate and adaptive inflammation as a therapeutic target in vascular disease: the emerging role of statins

Atherosclerosis, the main pathophysiological condition leading to cardiovascular disease (CVD), is now considered to be a chronic inflammatory condition. Statins are the most widely used and promising agents in treating CVD and are renowned for their pleiotropic lipid-lowering independent effects. Statins exert their anti-inflammatory effects on the vascular wall through a variety of molecular pathways of the innate and adaptive immune systems, their impact on the circulating levels of pro-inflammatory cytokines, and their effect on adhesion molecules. By inhibiting the mevalonate pathway and isoprenoid formation, statins account for the increase of nitric oxide bioavailability and the improvement of vascular and myocardial redox state by multiple different mechanisms (directly or indirectly through low-density lipoprotein [LDL] lowering). A large number of randomized control trials have shown that statins help in the primary and secondary prevention of cardiovascular events, not only via their lipid-lowering effect, but also due to their anti-inflammatory potential as well. In this paper, we examine the molecular pathways in which statins are implicated and exert their anti-inflammatory effects, and we focus specifically on their impact on innate and adaptive immunity systems. Finally, we review the most important clinical data for the role of statins in primary and secondary prevention of cardiovascular events.

Statins as anti-inflammatory agents in atherogenesis: molecular mechanisms and lessons from the recent clinical trials

Ample evidence exists in support of the potent anti-inflammatory properties of statins. In cell studies and animal models statins exert beneficial cardiovascular effects. By inhibiting intracellular isoprenoids formation, statins suppress vascular and myocardial inflammation, favorably modulate vascular and myocardial redox state and improve nitric oxide bioavailability. Randomized clinical trials have demonstrated that further to their lipid lowering effects, statins are useful in the primary and secondary prevention of coronary heart disease (CHD) due to their anti-inflammatory potential. The landmark JUPITER trial suggested that in subjects without CHD, suppression of low-grade inflammation by statins improves clinical outcome. However, recent trials have failed to document any clinical benefit with statins in high risk groups, such in heart failure or chronic kidney disease patients. In this review, we aim to summarize the existing evidence on statins as an anti-inflammatory agent in atherogenesis. We describe the molecular mechanisms responsible for the anti-inflammatory effects of statins, as well as clinical data on the non lipid-lowering, anti-inflammatory effects of statins on cardiovascular outcomes. Lastly, the controversy of the recent large randomized clinical trials and the issue of statin withdrawal are also discussed.

Sortilins: new players in lipoprotein metabolism

PURPOSE OF REVIEW

Sortilins are sorting receptors that direct proteins through secretory and endocytic pathways of the cell. Previously, these receptors have been shown to play important roles in regulating protein transport in neurons and to control neuronal viability and death in many diseases of the nervous system. Recent data, including genome-wide association studies, now suggest equally important functions for sortilins in control of systemic lipoprotein metabolism and risk of cardiovascular disease. This review discusses the evidence implicating two members of this gene family, sortilin and SORLA, in cardiovascular processes.

RECENT FINDINGS

SORLA is a multifunctional receptor expressed in macrophages and vascular smooth muscle cells. It may act proatherogenic by promoting intimal SMC migration and by regulating apolipoprotein A-V dependent activation of lipoprotein lipase to modulate systemic triglyceride levels. Sortilin, encoded by the cardiovascular risk locus 1p13.3, is a novel regulator of hepatic lipoprotein production. It interacts with apolipoprotein B-100 to control release of very low-density lipoproteins, thereby affecting plasma cholesterol concentrations.

SUMMARY

Recent data shed light on the importance of sorting receptors in control of cellular and systemic lipoprotein metabolism and how altered trafficking pathways may represent a major risk factor for dyslipidemia and atherosclerosis in the human population.

Pitavastatin for the treatment of primary hyperlipidemia and mixed dyslipidemia

Pitavastatin is a new, synthetic member of the statin class of lipid-lowering drugs. Compared with other available statins, it has a unique cyclopropyl group on its base structure that is believed to increase 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibition by a factor of five and to significantly increase the transcription and activity of LDL receptors. Pitavastatin is primarily metabolized via glucuronidation and is not a substrate for the cytochrome P450 3A4 enzyme, thus avoiding the potential for cytochrome P450-mediated drug-drug interactions. Clinical trials have shown that pitavastatin is comparable to atorvastatin and simvastatin in improving lipid measures, and more potent than pravastatin. Pitavastatin is effective in reducing triglycerides and increasing HDL-cholesterol, so it will be particularly beneficial in treating patients with mixed dyslipidemia. Its safety and adverse event profile is similar to that of other available statins, and it has an established history of use in Asia indicating tolerability and safety for treatment lasting up to 7 years.

Development of an Immunoassay for the Quantification of Soluble LR11, a Circulating Marker of Atherosclerosis

Background: Vascular smooth muscle cells (SMCs) migrate from the arterial media to the intima in the progression of atherosclerosis, and dysfunction of SMCs leads to enhanced atherogenesis. A soluble form of the LDL receptor relative with 11 ligand-binding repeats (sLR11) is produced by the intimal SMCs, and the circulating concentrations of sLR11 likely reflect the pathophysiological condition of intimal SMCs. Furthermore, polymorphism of the LR11 gene has been found to be related to the onset of Alzheimer disease. This study describes the development of a sandwich immunoassay for quantifying sLR11 in human serum and cerebrospinal fluid.

Methods: We used synthetic peptides or DNA immunization to produce monoclonal antibodies (MAbs) A2-2–3, M3, and R14 against different epitopes of LR11.

Results: sLR11 was immunologically identified as a 250-kDa protein in human serum and cerebrospinal fluid by SDS-PAGE separation, and was purified from serum by use of a receptor-associated protein and MAb M3. An immunoassay for quantification of sLR11 with a working range of 0.25–4.0 μg/L was developed using the combination of MAbs M3 and R14. Treatment of serum with 5.25% n-nonanoyl-N-methyl-d-glucamine reduced the matrix effects of serum on the absorbance detection in the ELISA system. The linear dynamic range of the ELISA spanned the variation of circulating sLR11 concentrations in individuals with atherosclerosis.

Conclusions: A sandwich ELISA was established for quantifying sLR11 in serum and cerebrospinal fluid. This technique provides a novel means for assessing the pathophysiology of atherosclerosis, and possibly neurodegenerative diseases.

Ang II-stimulated migration of vascular smooth muscle cells is dependent on LR11 in mice

Medial-to-intimal migration of SMCs is critical to atherosclerotic plaque formation and remodeling of injured arteries. Considerable amounts of the shed soluble form of the LDL receptor relative LR11 (sLR11) produced by intimal SMCs enhance SMC migration in vitro via upregulation of urokinase-type plasminogen activator receptor (uPAR) expression. Here, we show that circulating sLR11 is a novel marker of carotid intima-media thickness (IMT) and that targeted disruption of the LR11 gene greatly reduces intimal thickening of arteries through attenuation of Ang II-induced migration of SMCs. Serum concentrations of sLR11 were positively correlated with IMT in dyslipidemic subjects, and multivariable regression analysis suggested sLR11 levels as an index of IMT, independent of classical atherosclerosis risk factors. In Lr11-/- mice, femoral artery intimal thickness after cuff placement was decreased, and Ang II-stimulated migration and attachment of SMCs from these mice were largely abolished. In isolated murine SMCs, sLR11 caused membrane ruffle formation via activation of focal adhesion kinase/ERK/Rac1 accompanied by complex formation between uPAR and integrin alphavbeta3, a process accelerated by Ang II. Overproduction of sLR11 decreased the sensitivity of Ang II-induced activation pathways to inhibition by an Ang II type 1 receptor blocker in mice. Thus, we demonstrate a requirement for sLR11 in Ang II-induced SMC migration and propose what we believe is a novel role for sLR11 as a biomarker of carotid IMT.

Pitavastatin improves serum resistin levels in patients with hypercholesterolemia

AIM

Resistin in serum is associated with high risk in patients with atherosclerosis. This clinical study aimed to investigate whether pitavastatin can regulate the serum level of resistin, together with levels of other inflammatory cytokines and adipocytokines.

METHODS

Forty two outpatients (mean age 65.2 +/- 12.6 yr, M/F: 21/21) with hypercholesterolemia were administered 2 mg of pitavastatin and serum levels of resistin, together with serum levels of adiponectin, leptin, TNF-alpha and hsCRP, were measured before, and 12 weeks after enrollment.

RESULTS

There was no significant gender-related difference in initial serum resistin levels. Pitavastatin significantly decreased LDL-cholesterol after 12 weeks. Initial levels of resistin showed a significant correlation with those of hsCRP (r=0.38, p=0.013), but not TNF-alpha or HOMA-R. Serum resistin, but not adiponectin and leptin, levels were significantly decreased, dropping from 17.1 +/- 9.9 ng/ dL to 15.2+/-10.0 (p=0.001) after 12 weeks of administration. The patient group with a baseline hsCRP > or = 0.1 at enrollment (n=17) had decreased levels of both resistin and hsCRP (p=0.011 and p=0.022, respectively).

CONCLUSION

This study showed the pleiotropic effect of pitavastatin on the serum resistin concentration, suggesting that it may assist in the prevention of atherosclerosis.

Rosuvastatin regulates vascular smooth muscle cell phenotypic modulation in vascular remodeling: Role for the urokinase receptor

The urokinase (uPA)/urokinase receptor (uPAR) multifunctional system is an important mediator of migration and proliferation of vascular smooth muscle cells (VSMC). However, whether uPA/uPAR-directed mechanisms are involved in the beneficial effects of 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors on vascular remodeling remains unexplored. In this study, we have investigated the effect of the hydrophilic statin rosuvastatin on neointimal remodeling, and the role of uPAR. Using an ex vivo organ and in vitro cell culture models we demonstrate that rosuvastatin decreases injury-induced neointima formation and proliferation of medial VSMC in porcine coronary arteries, as well as migration and proliferation of human coronary VSMC. Studies on the underlying mechanisms show that rosuvastatin impairs VSMC transition from their physiological contractile to the pathophysiological synthetic phenotype. These effects are mediated, at least in part, via uPAR, as confirmed by means of rosuvastatin-directed uPAR expression and uPAR silencing in both models. Our findings provide evidence that rosuvastatin modulates VSMC phenotypic changes and subsequently their proliferation and migration, and indicate the important role for uPAR in these processes. This mechanism contributes to the beneficial non-lipid lowering effect of rosuvastatin on negative vascular remodeling.

A Secreted Soluble Form of LR11, Specifically Expressed in Intimal Smooth Muscle Cells, Accelerates Formation of Lipid-Laden Macrophages

OBJECTIVE

Macrophages play a key role in lipid-rich unstable plaque formation and interact with intimal smooth muscle cells (SMCs) in early and progressive stages of atherosclerosis. LR11 (also called sorLA), a member of low-density lipoprotein receptor family, is highly and specifically expressed in intimal SMCs, and causes urokinase-type plasminogen activator receptor-mediated degradation of extracellular matrices. Here we investigated whether the secreted soluble form of LR11 (solLR11) enhances adhesion, migration, and lipid accumulation in macrophages using animal models and cultured systems.

METHODS AND RESULTS

Immunohistochemistry showed solLR11 expression in thickened intima of balloon-denuded rat artery. Macrophage infiltration into the cuff-injured artery was markedly reduced in LR11-deficient mice. In vitro functional assays using THP-1-derived macrophages showed that solLR11 (1 microg/mL) significantly increased acetylated low-density lipoprotein uptake by THP-1 cells and cell surface levels of scavenger receptor SR-A 1.7- and 2.8-fold, respectively. SolLR11 dose-dependently increased the migration activity of THP-1 macrophages and adhesion to extracellular matrices 2.0- and 2.1-fold, respectively, at 1 microg/mL. These effects of solLR11 were almost completely inhibited by a neutralizing anti-urokinase-type plasminogen activator receptor antibody.

CONCLUSION

SolLR11, secreted from intimal SMCs, regulates adhesion, migration, and lipid accumulation in macrophages through activation of urokinase-type plasminogen activator receptor. The formation of lipid-laden macrophages in atherosclerotic plaques possibly is regulated by SolLR11 of intimal SMCs.

Prevention of stroke and dementia by statin therapy: Experimental and clinical evidence of their pleiotropic effects

Stroke and dementia are major causes of disability in most countries. Epidemiological studies have demonstrated that statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) are likely to reduce the risk for developing these formidable disorders. The favorable outcomes in statin users may be attributable to not only cholesterol-dependent actions, but also various cholesterol-independent actions called "pleiotropic effects." Several clinical trials have suggested that statins decrease the incidence of stroke, especially ischemic stroke. Statins improve endothelial function, inhibit platelet activation, reduce blood coagulability, and suppress inflammatory reactions, all of which may contribute to the beneficial effects of the therapy. Statins also reduce the risk of vasospasm caused by subarachnoid hemorrhage (SAH). In addition, statins might inhibit the development and progression of Alzheimer's disease (AD), the dominant type of dementia in most industrialized countries, upstream of the amyloid cascade. In vitro studies have shown that statins modulate the metabolism of the beta-amyloid precursor protein (APP) and reduce the extracellular level of its proteolytic product, amyloid-beta (Abeta). The aggregated Abeta is cytotoxic, leading to formation of neurofibrillary tangles and neuronal loss in the brain. Inflammatory processes are active in AD and may contribute significantly to AD pathology. We review the experimental background regarding the pleiotropic effects of statins and summarize clinical trials that examined the preventative effects of statin therapy on stroke and dementia. We include current trials in which statin therapy is initiated within 24 hr of onset of acute ischemic stroke.