Simvastatin reduces leucocyte- and platelet-endothelial cell interaction in murine antigen-induced arthritis in vivo

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.

Impact of lipid modulation on the intestinal microcirculation in experimental sepsis

It has been observed, that patients who were treated medically for dyslipoproteinemia had a potentially lower risk of complications during infection and sepsis, regarding both morbidity and mortality. Aim of this study in experimental sepsis was to elucidate the impact of lipid metabolism modulation by simvastatin, HDL, or bezafibrate, respectively, on the intestinal microcirculation which plays a crucial role in the development of multiple organ failure in sepsis. Experimental sepsis was induced in Lewis rats by intravenous lipopolysaccharide (LPS) administration. Animals were treated with simvastatin, HDL or bezafibrate. By means of intestinal intravital microscopy (IVM), the inflammatory response in the microcirculation was studied by leukocyte adherence assessment (LA) and functional capillary density (FCD) measurements. In addition, plasma levels of pro-inflammatory cytokines were determined. Bezafibrate treatment led to a reduction in leukocyte adherence, improved functional capillary density (FCD), and a reduction in interleukin-1α (IL-1α), tumour necrosis factor α (TNF-α) and granulocyte macrophage colony stimulating factors (GM-CSF) plasma levels in experimental sepsis. Contrary to this, the administration of HDL increased leukocyte adherence as well as the number of rolling leukocytes. Only IL-1α plasma levels were decreased by HDL. No significant changes were observed following simvastatin treatment. In summary, only bezafibrate showed anti-inflammatory effects in endotoxemia. This effect cannot be explained by the HDL-enhancing effect of the bezafibrate, since the direct administration of HDL showed opposite effects. Bezafibrate induced reduction of inflammation in sepsis should be investigated in further studies.

Attenuation of TNF-induced neutrophil adhesion by simvastatin is associated with the inhibition of Rho-GTPase activity, p50 activity and morphological changes

Neutrophil adhesion to the vasculature in response to potent inflammatory stimuli, such as TNF-α (TNF), can contribute to atheroprogression amongst other pathophysiological mechanisms. Previous studies have shown that simvastatin, a statin with known pleiotropic anti-inflammatory properties, can partially abrogate the effects of TNF-induced neutrophil adhesion, in association with the modulation of β₂-integrin expression. We aimed to further characterize the effects of this statin on neutrophil and leukocyte adhesive mechanisms in vitro and in vivo. A microfluidic assay confirmed the ability of simvastatin to inhibit TNF-induced human neutrophil adhesion to fibronectin ligand under conditions of shear stress, while intravital imaging microscopy demonstrated an abrogation of leukocyte recruitment by simvastatin in the microvasculature of mice that had received a TNF stimulus. This inhibition of neutrophil adhesion was accompanied by the inhibition of TNF-induced RhoA activity in human neutrophils, and alterations in cell morphology and β₂-integrin activity. Additionally, TNF augmented the activity of the p50 NFκB subunit in human neutrophils and TNF-induced neutrophil adhesion and β₂-integrin activity could be abolished using pharmacological inhibitors of NFκB translocation, BAY11-7082 and SC514. Accordingly, the TNF-induced elevation of neutrophil p50 activity was abolished by simvastatin. In conclusion, our data provide further evidence of the ability of simvastatin to inhibit neutrophil adhesive interactions in response to inflammatory stimuli, both in vivo and in vitro. Simvastatin appears to inhibit neutrophil adhesion by interfering in TNF-induced cytoskeletal rearrangements, in association with the inhibition of Rho A activity, NFκB translocation and, consequently, β₂-integrin activity.

Prevention of cardiovascular disease in rheumatoid arthritis

The increased risk of cardiovascular disease (CVD) in rheumatoid arthritis (RA) has been recognized for many years. However, although the characteristics of CVD and its burden resemble those in diabetes, the focus on cardiovascular (CV) prevention in RA has lagged behind, both in the clinical and research settings. Similar to diabetes, the clinical picture of CVD in RA may be atypical, even asymptomatic. Therefore, a proactive screening for subclinical CVD in RA is warranted. Because of the lack of clinical trials, the ideal CVD prevention (CVP) in RA has not yet been defined. In this article, we focus on challenges and controversies in the CVP in RA (such as thresholds for statin therapy), and propose recommendations based on the current evidence. Due to the significant contribution of non-traditional, RA-related CV risk factors, the CV risk calculators developed for the general population underestimate the true risk in RA. Thus, there is an enormous need to develop adequate CV risk stratification tools and to identify the optimal CVP strategies in RA. While awaiting results from randomized controlled trials in RA, clinicians are largely dependent on the use of common sense, and extrapolation of data from studies on other patient populations. The CVP in RA should be based on an individualized evaluation of a broad spectrum of risk factors, and include: 1) reduction of inflammation, preferably with drugs decreasing CV risk, 2) management of factors associated with increased CV risk (e.g., smoking, hypertension, hyperglycemia, dyslipidemia, kidney disease, depression, periodontitis, hypothyroidism, vitamin D deficiency and sleep apnea), and promotion of healthy life style (smoking cessation, healthy diet, adjusted physical activity, stress management, weight control), 3) aspirin and influenza and pneumococcus vaccines according to current guidelines, and 4) limiting use of drugs that increase CV risk. Rheumatologists should take responsibility for the education of health care providers and RA patients regarding CVP in RA. It is immensely important to incorporate CV outcomes in testing of anti-rheumatic drugs.