Anti-Thrombotic Effects of Statins in Acute Coronary Syndromes: At the Intersection of Thrombosis, Inflammation, and Platelet-Leukocyte Interactions

Statins-Beyond Their Use in Hypercholesterolemia: Focus on the Pediatric Population

Statins are a class of medications primarily used in adults to lower cholesterol levels and reduce the risk of cardiovascular events. However, the use of statins in children is generally limited and carefully considered despite the well-documented anti-inflammatory, anti-angiogenic, and pro-apoptotic effects, as well as their effect on cell signaling pathways. These multifaceted effects, known as pleiotropic effects, encompass enhancements in endothelial function, a significant reduction in oxidative stress, the stabilization of atherosclerotic plaques, immunomodulation, the inhibition of vascular smooth muscle proliferation, an influence on bone metabolism, anti-inflammatory properties, antithrombotic effects, and a diminished risk of dementia. In children, recent research revealed promising perspectives on the use of statins in various conditions including neurological, cardiovascular, and oncologic diseases, as well as special situations, such as transplanted children. The long-term safety and efficacy of statins in children are still subjects of ongoing research, and healthcare providers carefully assess the individual risk factors and benefits before prescribing these medications to pediatric patients. The use of statins in children is generally less common than in adults, and it requires close monitoring and supervision by healthcare professionals. Further research is needed to fully assess the pleiotropic effects of statins in the pediatric population.

Atorvastatin-mediated inhibition of prenylation of Rab27b and Rap1a in platelets attenuates their prothrombotic capacity and modulates clot structure

Statins inhibit the mevalonate pathway by impairing protein prenylation via depletion of lipid geranylgeranyl diphosphate (GGPP). Rab27b and Rap1a are small GTPase proteins involved in dense granule secretion, platelet activation, and regulation. We analyzed the impact of statins on prenylation of Rab27b and Rap1a in platelets and the downstream effects on fibrin clot properties. Whole blood thromboelastography revealed that atorvastatin (ATV) delayed clot formation time (P < .005) and attenuated clot firmness (P < .005). ATV pre-treatment inhibited platelet aggregation and clot retraction. Binding of fibrinogen and P-selectin exposure on stimulated platelets was significantly lower following pre-treatment with ATV (P < .05). Confocal microscopy revealed that ATV significantly altered the structure of platelet-rich plasma clots, consistent with the reduced fibrinogen binding. ATV enhanced lysis of Chandler model thrombi 1.4-fold versus control (P < .05). Western blotting revealed that ATV induced a dose-dependent accumulation of unprenylated Rab27b and Rap1a in the platelet membrane. ATV dose-dependently inhibited ADP release from activated platelets. Exogenous GGPP rescued the prenylation of Rab27b and Rap1a, and partially restored the ADP release defect, suggesting these changes arise from reduced prenylation of Rab27b. These data demonstrate that statins attenuate platelet aggregation, degranulation, and binding of fibrinogen thereby having a significant impact on clot contraction and structure.

Drug-Drug Interaction between Antiplatelet Therapy and Lipid-Lowering Agents (Statins and PCSK9 Inhibitors)

Lipid-lowering agents and antiplatelet drugs are guideline-recommended standard treatment for secondary prevention of acute thrombotic events in patients with increased cardiovascular risk. Aspirin is the most frequently used antiplatelet drug, either alone or in combination with other antiplatelet agents (P2Y₁₂ inhibitors), while statins are first-line treatment of hypercholesterolemia. The well-established mode of action of aspirin is inhibition of platelet-dependent thromboxane formation. In addition, aspirin also improves endothelial oxygen defense via enhanced NO formation and inhibits thrombin formation. Low-dose aspirin exerts in addition anti-inflammatory effects, mainly via inhibition of platelet-initiated activation of white cells.Statins inhibit platelet function via reduction of circulating low-density lipoprotein-cholesterol (LDL-C) levels and a more direct inhibition of platelet function. This comprises inhibition of thromboxane formation via inhibition of platelet phospholipase A₂ and inhibition of (ox)LDL-C-mediated increases in platelet reactivity via the (ox)LDL-C receptor (CD36). Furthermore, statins upregulate endothelial NO-synthase and improve endothelial oxygen defense by inhibition of NADPH-oxidase. PCSK9 antibodies target a serine protease (PCSK9), which promotes the degradation of the LDL-C receptor impacting on LDL-C plasma levels and (ox)LDL-C-receptor-mediated signaling in platelets similar to but more potent than statins.These functionally synergistic actions are the basis for numerous interactions between antiplatelet and these lipid-lowering drugs, which may, in summary, reduce the incidence of atherothrombotic vascular events.

Atorvastatin Attenuates Radiotherapy-Induced Intestinal Damage through Activation of Autophagy and Antioxidant Effects

Abdominal or pelvic radiotherapy (RT) often results in small intestinal injury, such as apoptosis of epithelial cells and shortening of the villi. Atorvastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, has many biological effects including cholesterol reduction, protection from cell damage, and autophagy activation. To reduce the extent of radiotherapy- (RT-) induced enteritis, we investigated the protective effects of atorvastatin against RT-induced damage of the intestinal tract. In this study, C57BL/6 mice were randomly distributed into the following groups (n = 8 per group): (1) control group: mice were fed water only, (2) atorvastatin group (Ator): mice were administered atorvastatin, (3) irradiation group (IR): mice received abdominal RT, (4) Ator+IR group: mice received abdominal RT following atorvastatin administration, and (5) Ator+IR+3-MA group: abdominal RT following atorvastatin and 3-methyladenine (an autophagy inhibitor) administration. Based on the assessment of modified Chiu's injury score and villus/crypt ratio, we found that atorvastatin administration significantly reduced intestinal mucosal damage induced by RT. Atorvastatin treatment reduced apoptosis (cleaved caspase-3 and cleaved poly (ADP-ribose) polymerase), DNA damage (γH2AX and 53BP1), oxidative stress (OS, 4-hydroxynonenal), inflammatory molecules (phospho-NF-κB p65 and TGF-β), fibrosis (collagen I and collagen III), barrier leakage (claudin-2 and fluorescein isothiocyanate-dextran), disintegrity (fatty acid-binding protein 2), and dysfunction (lipopolysaccharide) caused by RT in small intestinal tissue. In addition, atorvastatin upregulated the expression of autophagy-active molecules (LC3B), antioxidants (heme oxygenase 1 and thioredoxin 1), and tight junction proteins (occludin and zonula occludens 1). However, the biological functions of atorvastatin in decreasing RT-induced enteritis were reversed after the administration of 3-MA; the function of antioxidant molecules and activity of thioredoxin reductase were independent of autophagy activation. Our results indicate that atorvastatin can effectively relieve RT-induced enteritis through autophagy activation and associated biological functions, including maintaining integrity and function and decreasing apoptosis, DNA damage, inflammation, OS, and fibrosis. It also acts via its antioxidative capabilities.

Predictive Value of Inflammation Biomarkers in Patients with Portal Vein Thrombosis

BACKGROUND AND AIMS

To investigate the usefulness of inflammation biomarkers to serve as a predictors of portal vein thrombosis (PVT) postoperatively (post) in patients with portal hypertension after splenectomy and periesophagogastric devascularization.

METHODS

A total of 177 liver cirrhosis patients were recruited from January 2013 to December 2017. They were divided into a PVT group (n=71) and a non-PVT group (n=106), according to ultrasound examination findings at 7-day post. Inflammation biomarkers involving platelet-to-lymphocyte ratio (PLR), neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), red blood cell distribution width-to-platelet ratio(RPR), mean platelet volume-to-platelet ratio (MPR) preoperatively (pre) and at 1, 3, 7-days post were recorded.

RESULTS

The univariate logistic regression analysis indicated that PLR (pre) (odds ratio (OR)=3.963, 95% confidence interval (CI)=2.070-7.587, p<0.000), MLR (pre) (OR=2.760, 95% CI=1.386-5.497, p=0.004), PLR (post-day 7) (OR=3.345, 95% CI=1.767-6.332, p=0.000) were significantly associated with the presence of PVT. The multivariate logistic regression analysis results indicated that PLR (pre) (OR=3.037, 95% CI=1.463-6.305, p=0.003), MLR (pre) (OR=2.188, 95% CI=1.003-4.772, p=0.049), PLR(post-day 7) (OR=2.166, 95% CI=1.053-4.454, p=0.036) were independent factors for predicting PVT.

CONCLUSIONS

The PLR (pre), MLR (pre), and PLR (post-day 7) are predictors of portal vein thrombosis post in patients with portal hypertension after splenectomy and periesophagogastric devascularization.

Effect of Statins on Platelet Activation and Function: From Molecular Pathways to Clinical Effects

Purpose

Statins are a class of drugs widely used in clinical practice for their lipid-lowering and pleiotropic effects. In recent years, a correlation between statins and platelet function has been unveiled in the literature that might introduce new therapeutic indications for this class of drugs. This review is aimed at summarizing the mechanisms underlying statin-platelet interaction in the cardiologic scenario and building the basis for future in-depth studies.

Methods

We conducted a literature search through PubMed, Embase, EBSCO, Cochrane Database of Systematic Reviews, and Web of Science from their inception to June 2020.

Results

Many pathways could explain the interaction between statins and platelets, but the specific effect depends on the specific compound. Some could be mediated by enzymes that allow the entry of drugs into the cell (OATP2B1) and others by enzymes that mediate their activation (PLA2, MAPK, TAX2, PPARs, AKT, and COX-1), recruitment and adhesion (LOX-1, CD36, and CD40L), or apoptosis (BCL2). Statins also appear to have a synergistic effect with aspirin and low molecular weight heparins. Surprisingly, they seem to have an antagonistic effect with clopidogrel.

Conclusion

There are many pathways potentially responsible for the interactions between statins and platelets. Their effect appears to be closely related, and each single effect can be barely measured. Also, the same compound might have complex downstream signaling with potentially opposite effects, i.e., beneficial or deleterious. The multiple clinical implications that can be derived as a result of this interaction, however, represent an excellent reason to develop future in-depth studies.

The protective effect of statins against pressure ulcers in stroke patients: A propensity-score matched study based on a real-world database

BACKGROUND AND AIMS

Limited information is available regarding the association between statins and pressure ulcers. The purpose of this study is to evaluate the beneficial effects of statins on pressure ulcers in stroke patients.

METHODS

Using the claims data of Taiwan's National Health Insurance, we conducted a retrospective cohort study and identified new-onset stroke patients in 2000-2004. The propensity-score matching procedure was used to select eligible stroke patients with (n = 49,919) and without (n = 49,919) the use of statins. These two groups were followed until the end of 2009 to track the occurrence of pressure ulcers. Multivariate Cox proportional hazard models were conducted to calculate adjusted hazard rations (HRs) and 95% confidence intervals (CIs) of pressure ulcer associated with the use of statins.

RESULTS

Stroke patients who used statins had a reduced risk of pressure ulcers during the follow-up period (HR 0.74, 95% CI 0.71-0.78). The association between statin use and a reduced risk of poststroke pressure ulcers was significant in men (HR 0.73, 95% CI 0.68-0.78), women (HR 0.75, 95% CI 0.71-0.80), and people aged more than 50 years. Use of lovastatin, pravastatin, rosuvastatin, atrovastatin, fluvastatin, and simvastatin was associated with reduced poststroke pressure ulcers. There was a dose-dependent decrease in the frequency of pressure ulcers with increasing quantities of statins used, from 1 prescription to ≥3 prescriptions.

CONCLUSION

We raised the possibility that use of statins was associated with reduced risk of pressure ulcers in stroke patients. However, the potential beneficial effect associated with statins requires further validation using randomized clinical trials.

Analysis of Genetic Variation in CD40 and CD40L: Relationship with mRNA Relative Expression and Soluble Proteins in Acute Coronary Syndrome

Acute coronary syndrome (ACS) can be triggered by the presence of inflammatory factors which promote the activation of immune cells by costimulatory molecules such as CD40 and its ligand CD40L. Environmental and genetic factors are involved in the etiology of the ACS. The aim of this study was to explore the gene and protein expression associated with CD40 and CD40L genetic variants in ACS patients from the western Mexican population. A total of 620 individuals from western Mexico were recruited: 320 ACS patients and 300 individuals without a history of ischemic cardiopathy were evaluated. The genotype was determined using TaqMan SNP genotyping assays. CD40 and CD40L expressions at the mRNA level were quantified using TaqMan Gene Expression Assays. Soluble protein isoforms were measured by enzyme-linked immunosorbent assay. We did not find evidence of association between CD40 (rs1883832, rs4810485, and rs11086998) and CD40L (rs3092952 and rs3092920) genetic variants and susceptibility to ACS, although rs1883832 and rs4810485 were significantly associated with high sCD40 plasma levels. Plasma levels of sCD40L can be affected by gender and the clinical spectrum of acute coronary syndrome. Our results do not suggest a functional role of CD40 and CD40L genetic variants in ACS. However, they could reflect the inflammatory process and platelet activation in ACS patients, even when they are under pharmacological therapy. Due to the important roles of the CD40-CD40L system in the pathogenesis of ACS, longitudinal studies are required to determine if soluble levels of CD40 and CD40L could be clinically useful markers of a recurrent cardiovascular event after an ACS.

Platelet Hyperreactivity in Diabetes: Focus on GPVI Signaling-Are Useful Drugs Already Available?

Adults with diabetes are 2-4 times more likely to suffer from heart disease or ischemic stroke than adults without diabetes, yet standard antiplatelet therapy, which is the cornerstone for primary and secondary prevention of cardiovascular disease, fails in many patients with diabetes. Three independent but often interrelated variables that contribute to platelet hyperreactivity-high blood glucose, oxidative stress, and elevated vascular shear forces-coexist in patients with diabetes, creating a perilous concurrence of risk factors for cardiovascular events. Recent research has focused attention on the platelet-specific collagen receptor glycoprotein VI (GPVI) as a potential antithrombotic target. Signaling events downstream of GPVI are influenced by hyperglycemia, oxidative stress, and shear stress. Importantly, drugs targeting these GPVI signaling pathways are already in existence. The potential to repurpose existing drugs is a high-gain strategy for yielding new antiplatelet agents and could have particular benefit in individuals with diabetes.